CN1868033A - Multilayer mirror, method for manufacturing the same, and exposure equipment - Google Patents

Abstract

A multilayer film reflection mirror intended to reduce the dependency of reflectance on an incident angle. A substrate (1) is made of a low-thermal-expansion glass polished until its surface (top surface in the FIG.) has a roughness of up to 0.2 nmRMS. An Ru/Si multilayer film (3) having the large half width of peak reflectance is formed on the surface of the substrate (1), and an Mo/Si multilayer film (5) having a high peak reflectance is formed on this Ru/Si multilayer film (3). Accordingly, a reflectance peak having a higher reflectance than the case with of Ru/Si only and a larger half width than the case with of Mo/Si multilayer film (5) only is obtained. Since Ru provides a larger EUV beam absorption than Mo, a higher reflectance than with the case of a structure in which the Ru/Si multilayer film (3) is formed on the Mo/Si multilayer film (5) is obtained. Since a multilayer film having a larger half width at a spectral reflectance has a smaller dependency of reflectance on an angle, the invention can keep a high imaging performance in a projection optical system.

Description

Multilayer film reflector, method for manufacturing multilayer film reflector, and exposure system

technical field

The present invention relates to multilayer mirrors and the like used in EUV lithography, and more particularly, to techniques for reducing the dependence of reflectance on the surface of the mirror on the incident angle.

Background technique

At present, as a method of manufacturing semiconductor integrated circuits, reduced projection exposure capable of achieving a high processing speed is widely used. In this reduced projection technique, as semiconductor integrated circuit devices become finer, a projection lithography technique using soft X-rays having a wavelength of about 11 to 14 nm instead of ultraviolet rays has been developed (see Non-Patent Document 1). Recently, this technique is also referred to as EUV (Extreme Ultraviolet, Soft X-ray) lithography. The EUV lithography technology is expected to be a technology having a resolution of 45 nm or less, which is impossible with conventional lithography technology (wavelength of about 190 nm or more).

At the same time, lenses that are transmissive optical elements can be used in current mainstream reduction projection optical systems that use visible light or ultraviolet rays. The optical system for reduced projection requiring high resolution consists of several lenses. In contrast, in the wavelength range of EUV rays (soft X-rays), there is no transparent material, and the refractive index of the material is very close to 1, so conventional optical elements using refraction cannot be used. Instead, glancing mirrors utilizing total reflection, multilayer mirrors capable of obtaining overall high reflectance by adjusting the phase of weakly reflected light at an interface to overlap several reflected rays, and the like are used.

In a projection optical system using a lens, it is possible to realize an optical system in which light rays advance in one direction along an optical axis, however, in a projection optical system configured with mirrors, light beams are returned multiple times. Therefore, it is necessary to prevent the returning beam from spatially interfering with the mirror substrate and to limit the numerical aperture (NA) in the optical system.

Presently, a projection optical system consisting of four to six mirrors is recommended. In order to obtain sufficient resolution, the numerical aperture of the projection optical system is preferably larger, therefore, an optical system composed of six mirrors capable of obtaining a large numerical aperture is considered desirable. As an example of a six-mirror optical system, Takahashi et al. proposed a structure (see Patent Document 1 and FIG. 21 later).

In order for the reduced projection optical system to exhibit sufficient performance in reduced projection exposure, the structure of the illumination optical system is also important. In order for the projection optical system to exhibit sufficient resolution, it is necessary to make the light irradiation intensity in the pupil uniform, and to irradiate with uniform intensity the exposure area on the mask where the circuit pattern to be transferred is formed. In addition, it is also important to shine as strong a light as possible in order to ensure throughput. As an example of such an illumination optical system, it is disclosed in Patent Document 2, for example.

In the multilayer mirrors constituting the EUV optical system, materials suitable for obtaining high reflectivity differ depending on the wavelength range of incident light. For example, in a wavelength range close to 13.5 nm, if a molybdenum (Mo) layer and a silicon (Si) layer are sequentially laminated using a molybdenum Mo/Si multilayer film, a reflectance of 67.5% can be obtained for normal incidence. In addition, in the wavelength range close to 11.3 nm, if a Mo/Be multilayer film in which a molybdenum (Mo) layer and a beryllium (Be) layer are sequentially laminated is used, a reflectance of 70.2% can be obtained for normal incidence (see non-patent literature 2). According to reports in Non-Patent Document 2, in the case of Mo/Si multilayer films, the half width at half width (FWHM) of the reflectance peak of the multilayer film is about 0.56 nm, and its period length has been adjusted so that for normal incidence at There is a peak at a wavelength of 13.5 nm.

At the same time, it is well known that the reflectivity of multilayer mirrors varies significantly with the incident angle and wavelength of light. Figure 19 illustrates the relationship between the reflectivity and the incident angle of a conventional multilayer mirror. In this figure, the horizontal axis represents the incident angle (degrees (°)) of light incident on the multilayer film mirror, and the vertical axis represents the reflectance (%) of EUV rays with a wavelength (λ) of 13.5 nm. As shown in the figure, in conventional multilayer mirrors, a high reflectance of 70% or more is obtained when the incident angle is about 0° to 5°, however, when it is above 10°, the reflectance is Decreased significantly.

Figure 20 illustrates the spectral reflectance performance of conventional multilayer mirrors. In the figure, the horizontal axis represents the wavelength (λ) of incident light, and the vertical axis represents the reflectance (%). Note that its angle of incidence is assumed to be 0° (perpendicular projection onto the reflective surface). As can be seen from the figure, in the traditional multilayer reflector, a high reflectance of 70% or more is obtained near the wavelength of 13.5nm (the central part of the figure), however, in other wavelength ranges, the reflectance drops significantly.

For such a problem, Kuhlmann et al. have proposed a reflective multilayer film having approximately uniform reflectance over a wide wavelength range by making the periodic structure (film thickness of each layer) of the reflective multilayer film non-uniform. Multilayer film (see Non-Patent Document 3). Non-Patent Document 3 discloses a multilayer film structure having a wide range for reflectance angular distribution or spectral reflectance by adjusting each layer of a 50-layer multilayer film by using a commercially available multilayer film optimization program. obtained from the film thickness.

For example, in the case where the periodic length of the multilayer film is constant, if the periodic length is optimized to maximize the reflectivity at normal incidence, the range that can maintain high reflectivity is when the incident angle is 0° to 5°, when When the incident angle is 10° or more, the reflectance drops significantly. In contrast, Non-Patent Document 3 discloses a multilayer film having a non-uniform film thickness structure whose reflectance is almost constant at about 45% in the incident angle range of 0° to 20°. Although the half-width (FWHM) of the spectral reflectance peak of a normal Mo/Si multilayer film is about 0.56 nm, Non-Patent Document 3 also discloses a structure whose reflectance in the wavelength range of 13 nm to 15 nm for normal incidence Almost steady at 30%.

The above-mentioned uniformity of reflectance over a wide wavelength range and uniformity over a wide range of incident angles are not properties that can be individually controlled. In a multilayer film that can obtain uniform reflectance over a wide wavelength range, there is a tendency that , the change in reflectivity becomes small even in a wide range of incident angles. A multilayer film that can obtain uniform reflectance in such a wide wavelength range can utilize EUV rays in a wide wavelength region, although its reflection peak is lower than that of a general multilayer film, so when the incident light has a wide wavelength range can expect to get a lot of lighting depending on its application.

In addition, Singh et al. have reported that by making the Γ value (the ratio of the periodic length of the multilayer film to the thickness of the Mo layer) of the Mo/Si multilayer film non-uniform in the depth direction, thereby increasing the reflectivity (see Non-Patent Literature 4). The EUV reflectance of the Mo/Si multilayer film reaches the maximum when the Γ value is 0.35 to 0.4, however, Non-Patent Document 4 discloses that when the Γ value of Mo/Si at the base side (deep layer side) part of the multilayer film is Closer to 0.5, it is possible to obtain a larger increase in reflectance than when it is set at a constant value of 0.4 for the entire multilayer film.

Meanwhile, as a reflective multilayer film structure capable of obtaining high reflectivity for EUV rays with a wavelength close to 13 nm, there is Ru/Si (Ru represents ruthenium) in addition to Mo/Si. If it is assumed that n is the refractive index and k is the extinction coefficient (the imaginary part of the complex refractive index), the optical constant (n, k) of silicon at a wavelength of 13.5nm is

n(Si)=0.9993, and

k(Si)=0.0018.

The optical constants (n, k) of molybdenum and ruthenium are respectively

n(Mo)=0.9211,

k(Mo)=0.0064,

n(Ru)=0.8872, and

k(Ru)=0.0175.

As with the multilayer film for EUV rays, when the multilayer film itself absorbs light, in order to obtain high reflectance, it is preferable that the difference in refractive index of the substances constituting the multilayer film is large and the absorption is small. It can be seen from the above optical constants that from the viewpoint of refractive index, Ru/Si multilayer film is suitable, while from the viewpoint of absorption, Mo/Si multilayer film is more suitable for obtaining high reflectivity. In the case of both multilayers, the effect of absorption is dominant, and the Mo/Si multilayer has a higher peak reflectivity.

The half-width of the reflectance peak of the multilayer film is caused by the refractive index difference. It is known that the full bandwidth of the reflectance peak of a dielectric multilayer film (a multilayer film in which two substances having different refractive indices are laminated in sequence) well known in the fields of infrared rays, visible light, and ultraviolet rays is expressed by the following formula (for example, See Non-Patent Document 5).

[mathematical formula 1]

$\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&Delta;g</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; sin</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Here, n _H is the refractive index of a high-refractive-index substance, and n _L is the refractive index of a low-refractive-index substance.

It can be seen from the above formula that the greater the refractive index difference between the two substances constituting the multilayer film, the more the band will increase. Therefore, the ratio of Ru/Si multilayer film to Mo/Si multilayer film can be obtained Wider half-width. In the case of non-absorbing layers, the peak reflectance of the dielectric multilayer film gradually reaches 100%, however, it does not reach 100% in the EUV region due to absorption.

Since the amount of absorption is wavelength dependent, if the change in reflectance is plotted against wavelength, the reflectance around the peak wavelength is asymmetrical. The peak reflectance of multilayer films in the EUV region increases with the number of layers formed, however, saturates at a certain layer log. The number of layer pairs at which saturation is reached is about 50 layer pairs for Mo/Si multilayers and about 30 layer pairs for Ru/Si. The reason for the saturation of the reflectance is that when the EUV rays pass through the coating, the reflection and absorption of each boundary surface make almost no light reach the deeper part and no longer contribute to the reflection of the entire coating. The absorption of Ru/Si multilayer film is larger than that of Mo/Si multilayer film, and its reflectivity at a single interface is also higher, therefore, the number of layers to reach saturation is smaller.

Patent Document 1: Japanese Unexamined Patent Application Publication Publication No. 2003-15040

Patent Document 2: Japanese Unexamined Patent Application Publication Publication No. 11-312638

Non-Patent Document 1: Daniel A. Tichenor and 21 others, "Recent results in the development of an integrated EUVL laboratory tool", Proceedings of SPIE, United States (USA), [SPIE, The International Society for Optical Engineering], May 1995, Vol. 2437, p. 293

Non-Patent Document 2: Claude Montcalm and 5 others, "Multilayer reflective coatings forextreme-ultraviolet lithography", SPIE Proceedings, USA, (SPIE, Optical Engineering International Society), June 1989, Vol. 3331, p. 42

Non-Patent Document 3: Thomas Kuhlmann and 3 others, "EUV multilayer mirrors with tailored spectral reflectivity", SPIE Proceedings, USA, (SPIE, International Society for Optical Engineering) , 2003, Vol. 4782, p. 196

Non-Patent Document 4: Mandeep Singh and another person, "Improved Theoretical Reflectivities of Extreme Ultraviolet Mirrors", SPIE Proceedings, USA, July 2000, Vol. 3997, No. 412 Page

Non-Patent Document 5: Written by H.A. Macleod, translated by Shigetaro Ogura and 3 others, "Optical Thin Film", Nikkan Kogyo Shimbun Co., Ltd., November 1989

Contents of the invention

The projection optical system actually used in EUV lithography consists of a multilayer mirror in which a Mo/Si multilayer is formed on a substrate.

Fig. 21 illustrates a projection optical system composed of 6 mirrors. The projection optical system is composed of six mirrors CM1 to CM6, and the light reflected by the mask M is projected onto the wafer W. The four mirrors CM1 to CM4 on the upstream side (the side close to the mask M) in the optical system constitute the first reflected image forming optical system G1 to form an intermediate image of the mask composition on the mask M, while the downstream The two mirrors CM5 and CM6 on the side (closer to the wafer W side) constitute the second reflected image forming optical system G2 for projecting the intermediate image patterned by the mask on the wafer W in reduced size.

Light rays reflected by the mask M are reflected by the reflective surface R1 of the first concave mirror CM1 and reflected by the reflective surface R2 of the second convex mirror CM2. The light reflected by the reflective surface R2 passes through the perforated diaphragm AS, and then is sequentially reflected by the reflective surface R3 of the third convex mirror CM3 and the reflective surface R4 of the fourth concave mirror CM4, forming an intermediate image of the mask pattern. Next, light rays from the intermediate image patterned by the mask formed via the first reflected image forming optical system G1 are reflected by the reflective surface R5 of the fifth convex mirror CM5 and the reflective surface R6 of the sixth concave mirror CM6, thus forming an image on the wafer W. A reduced image of the mask composition.

The periodic length distribution in the base plane of the Mo/Si multilayer film formed on the surface of the mirror directly affects the reflectivity distribution in the plane, and the in-plane distribution of the reflectivity acts as the in-plane illuminance variation on the formed image surface Variations in the amount of light in the or pupil plane affect image forming performance, so it is necessary to take them all into account to establish an optimal in-plane distribution. However, since it is difficult to form a film layer having a free film thickness distribution on a substrate, when an optical system is provided, an axisymmetric film thickness distribution around the optical axis of the optical system is generally optimized.

Even if the periodic length distribution is optimized as described above, the following problems remain. In the projection optical system shown in Fig. 21, the light rays reaching a certain point on the image forming surface do not come from only one direction reaching the image forming surface, but from a solid angle which can be converged into a point to some extent space. In other words, a ray that contributes to image formation at a point on the image forming surface has an area on each mirror substrate having a finite area, and mirrors corresponding to two points on the image forming surface that are not too apart The substrate is reflected in two regions that partly overlap each other. In other words, reflections at a single point on the mirror substrate will contribute to image formation in an area with some extent on the image forming surface, and rays reflected at the same point will reach different points on the image forming surface. At this time, light rays reaching different points on the image forming surface are incident on the same point on the reflective mirror at different angles, and therefore, the incident angle at a certain point on the reflective surface has a certain range.

In multilayer mirrors, the optimal period length for a fixed wavelength depends on the angle of incidence, so, strictly speaking, there is no optimal period length for all angles of incidence. If the range of incidence angles is not so large, its influence is not great. However, even if the in-plane distribution of the periodic length of the general Mo/Si multilayer film is optimized for the mirror substrate constituting the optical system (the periodic length is constant), for example, as shown in FIG. 21, so that the transmitted The wave surface deviation of the light becomes smaller and the light intensity in the pupil plane changes greatly. Here, under the constraints of the above-mentioned film forming method, when configuring the optical system, the distribution of the period length of the multilayer film is optimized within the range of axisymmetric distribution around the optical axis.

The light intensity variation in the pupil plane is optically equivalent to the effective NA becoming irregularly smaller, and therefore, the image forming performance drops significantly. This is a problem that occurs in normal Mo/Si multilayers because of the large dependence of reflectivity on incident angle. Therefore, there is a demand for a method of reducing the incidence angle dependence of the reflectivity that degrades the image forming performance, which can achieve high image forming performance.

In addition, in order to obtain high image forming performance in the projection optical system, it is necessary to make the illumination light intensity distribution on the mask and the light intensity distribution in the pupil plane in the illumination optical system uniform. This is because the light intensity distribution in the pupil plane in the illumination optical system is directly reflected on the intensity distribution on the image forming surface and the intensity distribution in the pupil plane in the projection optical system.

Furthermore, in multilayer mirrors in illumination optical systems proposed recently, the in-plane distribution of incident angles is large. Therefore, it is difficult to strictly match the optimal period length for all points on the reflective surface. This is because the amount of variation in the in-plane periodic length distribution needs to increase, and due to the slight shift when the periodic length distribution is controlled when the film is formed, or when the illumination optical system is calibrated, corresponding to the assumed The film thickness at the incident angle differs from the film thickness corresponding to the actual incident angle, resulting in a significant decrease in reflectance. In this case, there is a problem that the amount of light that can be used for illumination decreases, and the yield decreases. Therefore, there is a need for a technique for reducing the dependence of the reflectivity on the mirror surface on the angle of incidence.

An object of the present invention is to provide a technique for reducing the incidence angle dependence of reflectance on a multilayer film mirror or the like.

According to the first embodiment of the present invention, the multilayer mirror has a reflective multilayer film in which a high-refractive-index film layer and a low-refractive-index film layer for EUV rays are sequentially laminated, which has the following features. First, in the multilayer film (surface film layer group) on the light incident plane side, the low refractive index film layer is composed of a substance including molybdenum (Mo), and the high refractive index film layer is composed of a substance including silicon (Si) . Second, in the multilayer film (deep layer group) on the opposite side of the light incident plane of the surface layer group, the low-refractive-index layer is made of a substance including ruthenium (Ru), and the high-refractive-index layer is made of a substance including The material composition of silicon.

Here, the high-refractive-index film layer or the low-refractive-index film layer may be a single film layer or a composite film layer in which multiple film layers overlap. In addition, another film layer may be inserted between the high-refractive-index film layer and the low-refractive-index film layer.

According to the present invention, substrates comprising molybdenum also include, for example, rhodium (Rh), carbon (C), silicon (Si), and the like. In other words, the molybdenum-containing substrate may be molybdenum containing impurities Rh, C, and Si, or may be a compound of these and molybdenum (the same applies to the ruthenium-containing substance and the silicon-containing substance). In addition, substances including ruthenium also include, for example, rhodium (Rh), carbon (C), silicon (Si), and the like. In addition, substances including silicon also include, for example, carbon (C), carbon tetraboride (B ₄ C), boron (B), and the like.

According to the first embodiment described above, the Mo/Si multilayer film having a high reflectance peak is formed on the Ru/Si multilayer film having a large half width of the reflectance peak, so it is possible to obtain The reflectance is higher in the case of Mo/Si multilayer, and the reflectance peak has a wider half-width than in the case of only the Mo/Si multilayer film. In addition, Ru absorbs more EUV rays than Mo, and thus will obtain a higher reflectance than in a structure in which a Ru/Si multilayer film is formed on a Mo/Si multilayer film. A multilayer film having a wide half-width with respect to spectral reflectance has a small dependence of reflectance on incident angle, which enables the projection optical system according to the present invention to maintain high image forming performance.

According to the first embodiment, preferably, the number of pairs of high refractive index film layers and low refractive index film layers in the surface film layer group is 2 to 10. The lamination number of the Mo/Si multilayer film is 10 or less, and therefore, due to the influence from Ru/Si formed on the base side, the half width of the reflectance peak remains broad. In addition, since the outermost layer is a Mo/Si multilayer film having higher reflectance than the Ru/Si multilayer film, the peak reflectance increases. This makes it possible to obtain a multilayer film having a high reflectance and a wide half width that cannot be obtained with a single Mo/Si multilayer film or a single Ru/Si multilayer film.

Fig. 22(A) is a graph showing the incident wavelength dependence of the theoretical reflectance of a Mo/Si multilayer film and a Ru/Si multilayer film. In this figure, the horizontal axis represents the wavelength of incident light, and the vertical axis represents the theoretical reflectance (calculated value of reflectance). The solid line in the figure represents the theoretical reflectance of the Mo/Si multilayer film with 100 pairs of film layers, and the dotted line represents the theoretical reflectance of the Ru/Si multilayer film with 100 pairs of film layers. It can be seen from FIG. 22(A) that the half width of the Mo/Si multilayer film having a sufficiently large formation layer logarithm of 100 layers is 0.6 nm, and that of the Ru/Si multilayer film is 0.8 nm.

22(B) is a graph showing the half width and peak reflectance with respect to the formed film of the Mo/Si multilayer film in the multilayer film formed by forming the Mo/Si multilayer film on the Ru/Si multilayer film logarithmic change. In the figure, the horizontal axis represents the number of layer pairs of the Mo/Si multilayer film formed on the 100 pair Ru/Si multilayer film. The half-width with respect to the number of layer pairs of the Mo/Si multilayer film is indicated by white triangles (△), and the reflectance peak is indicated by black circles (•).

It can be seen from FIG. 22(B) that as the number of layer pairs of the Mo/Si multilayer film increases, the reflectance peak increases, however, when the number of layer pairs becomes 15 or more, the peak is almost saturated. On the other hand, as the number of layer pairs of the Mo/Si multilayer film decreases, the half width decreases. Thus, when the number of layer pairs of the Mo/Si multilayer film becomes 15, the half width decreases below 0.7 nm and approaches the value of the Mo/Si multilayer film (see FIG. 22(A)).

As mentioned above, in order to obtain the effect of increasing the reflectivity and minimize the effect of reducing the half-width, it is preferable that the number of formed film layer pairs of the Mo/Si multilayer film is two or more pairs, more preferably 5 to 10 pairs. The multilayer film mirror in the first embodiment is manufactured by the following method. In other words, it is only necessary for the method to have the steps of forming a deep layer group by alternately depositing a substance including ruthenium and a substance including silicon on the substrate, and alternately depositing a substance including molybdenum and a substance including silicon on the deep layer group To form the process of surface film layer group.

According to a second embodiment of the present invention, the multi-layer mirror has a reflective multi-layer film in which high-refractive-index film layers and low-refractive-index film layers for EUV rays are alternately laminated. This multilayer film mirror has the following features. First, it has a multilayer film group on the side of the light incident plane (surface film layer group), an additional layer on the side of the surface film layer group opposite the incident plane, and a multilayer film group on the side opposite the incident plane of the additional layer (deep layer group). Second, due to the presence of the additional layer, the phase of the reflected light changes, so that the reflectivity peak in the mirror decreases overall, while the reflectivity around the peak wavelength increases compared to the situation without the additional layer.

According to a third embodiment of the present invention, the multi-layer mirror has a reflective multi-layer film in which high-refractive-index film layers and low-refractive-index film layers for EUV rays are alternately laminated. This multilayer film mirror has the following features. First, it has a multilayer film group on the side of the light incident plane (surface film layer group), an additional layer on the side of the surface film layer group opposite the incident plane, and a multilayer film group on the side opposite the incident plane of the additional layer (deep layer group). Second, in the surface film layer group, the low-refractive index film layer is composed of a substance including ruthenium (Ru), and the high-refractive index film layer is composed of a substance including silicon (Si). Thirdly, in the deep layer group, the low-refractive index layer is composed of a substance including ruthenium (Ru), and the high-refractive index layer is composed of a substance including silicon (Si). Fourth, the thickness of the additional layer is about half the period length of the multilayer film, or about half the period length plus an integer multiple of the period length. Note that the low-refractive index film layer in the surface film layer group may be composed of a substance including molybdenum (Mo) instead of the above-mentioned substance including ruthenium (Ru). In addition, the low-refractive-index film layer in the deep film may also be composed of a substance including molybdenum (Mo) instead of ruthenium.

In the multilayer reflectors in the above-mentioned second and third embodiments, the number of unit periodic structures (layer pairs) of the preferred surface film layer group is 10 to 30, and the logarithm of the deep film layer group is the surface film layer group 5 to 50% of the logarithm.

In the multilayer film mirrors in the second and third embodiments, the additional layer is at the position of the tenth to thirtieth period from the top surface of the multilayer film, however, EUV rays will reach a position deeper than the additional layer . Therefore, reflected light from the multilayer group (deep layer group) on the side opposite to the plane of incidence (substrate side) of the additional layer contributes to the reflectance of the entire multilayer film.

The thickness of the additional layer is such that the phase of the reflected light rays from the periodic multilayer film above and below the additional layer (incident plane side and opposite incident plane side) changes in phase around the reflection peak, so the amplitude of the reflected light rays is attenuated. Therefore, the reflectance decreases at the front end of the reflectance peak due to the presence of the additional layer. The shape at the peak of the reflectance peak in a multilayer film whose logarithm is smaller than the logarithm of the film layer at which the reflectivity is saturated is sharp, however, as the reflectivity of the peak decreases, the peak top approaches flat (peak part will be able to withstand wider performance).

On the other hand, the situation is clearly different at the peak valley portion other than the peak. In a general periodic structure, when the wavelength deviates from the optimum wavelength (the wavelength at which the reflectance peak is obtained), the phase change of the reflected light from the interface near the surface is small, and therefore, the amplitude increases by overlapping each other, however, it is also possible The phase of the reflected light rays from the interface leaving the surface is changed to the opposite phase reducing the amplitude. At wavelengths corresponding to the peaks and valleys of reflectivity of Mo/Si or Ru/Si multilayers, the effect of reflected light from 10-30 pairs of interfaces behind the film will reduce the reflected light intensity. However, if additional layers are added, the phase of reflected rays from the boundary at deeper sites shifts by half a wavelength, and thus, the amplitude of the reflected rays increases.

As described above, by providing an additional layer between the surface layer group and the deep layer layer group, the front end of the reflectance peak is flattened, and at the tail of the reflectance (peak), the reflectance increases, and therefore, the peak of the reflectance The half-width increases. In the case of a Ru/Si multilayer film or a Mo/Si multilayer film, in the wavelength range of 12 to 15 nm, theoretically, a reflectance exceeding 60% can be obtained. By making these multilayer films adopt the multilayer film structure according to the present invention, it is possible to obtain a multilayer film having a wider half width of reflectance than Ru/Si and Mo/Si without additional layers.

Fig. 23 shows the shape of the reflectance peak when the thickness of the additional layer (silicon layer in this example) is varied relative to the period length of the Mo/Si multilayer film. In the figure, the horizontal axis represents the wavelength of incident light, and the vertical axis represents the reflectance. In the figure, the solid line (i) represents the wavelength performance of the reflectance when the thickness of the additional layer is set to be about the half-periodic length of the multilayer film (= about 3.5 nm), and the dashed line (ii) and the dot-dash line (iii) represent the case when the thickness of the additional layer (thickness of the additional layer = about 2.8 nm) is set to be thinner than about the half-periodic length (= about 3.5 nm) of the multilayer film, and the thickness (thickness of the additional layer = about 3.5 nm), respectively, and The thickness of the layer = about 4.2 nm) is set to be thicker than the case.

It can be seen from FIG. 23 that in the case of the dotted line (ii) and the dotted line (iii), the top is not very flat, but in the case of the solid line (i), the top of the reflectance peak is quite flat. It is clear that setting the thickness of the additional layer to about the half-periodic length of the multilayer film will effectively reduce the reflectance variation near the peak.

The half-periodic length of the multilayer film refers to half of the optical thickness (film thickness×refractive index) of one period in the periodic structure part in the multilayer film. The thickness of the additional layer is preferably this semi-optical thickness, however, it is not necessary strictly to be the above-mentioned semi-optical thickness, it is only necessary to be substantially this thickness. Therefore, it is preferred that the difference between the thickness of the additional layer and the semi-optical thickness is within 5/100 of the wavelength of the EUV radiation employed, more preferably within 3/100 of the wavelength of the employed EUV radiation.

The optical thickness of one cycle in a multilayer structure is about half the wavelength of the incident light, so, in other words, it is necessary to set the optical thickness of the additional layer to about 1/4 of the wavelength used. Note that as the angle (refraction angle) between the transmitted EUV ray and the interface normal increases, the optical path length in the unit periodic structure becomes longer than the film thickness (if the refraction angle is assumed to be θ, the optical path length = film thick/cosθ). Therefore, it is necessary to adjust the thickness of the additional layer according to the incident angle of EUV rays when used. When the wavelength used is e.g. 13.5 nm, the thickness of the additional layer is preferably within the range of half-period length ± 0.68 nm of the multilayer film, and preferably within 3.4 ± 0.68 nm when the incident angle ranges from 5° to 10° In the range.

In addition, the multilayer film structure according to the present invention is for infrared, visible and ultraviolet rays, and can also be considered similar to an etalon (Etalon), where a space of 1/4 the thickness of the wavelength used is added between reflective films. However, the multilayer film according to the present invention is quite different from the etalon in terms of structure, purpose of use, and characteristics described below. The calibrator is a Fabry-Perot type resonator used primarily as a narrow band filter.

Fig. 24 is a schematic structural diagram of a calibrator. The etalon 300 is a device utilizing multiple interference, and in its structure, two high-reflectivity mirrors 301 are configured such that a partition 302 with a certain thickness is sandwiched between them. Most of the light ray 303 (see left arrow) entering etalon 300 is reflected to the left side of the figure as reflected ray 305 . On the other hand, the two mirrors 301 and the spacer 302 function as a resonator, allowing only the light with a wavelength satisfying the resonance condition among the incident light 303 to pass as the transmitted light 304 .

This results in a sharp transmission peak. Since the etalon 300 passes only light having a wavelength satisfying the resonance condition as described above, the reflectance decreases only around this wavelength, while maintaining high reflectance at other wavelengths. Thus, the spectral reflectance performance of etalon 300 has sharp valleys. Note that the etalon 300 is used as a narrowband filter, and the reflectivity of the two reflective surfaces should be high and nearly equal.

In contrast, in the case of the multilayer film of the present invention, the reflectance of the multilayer film above and below the additional layer must not be equal, and the reflectance of the multilayer film on the substrate side must be low . If the reflectance of the multilayer film on the base side is equal to that of the multilayer film on the surface side, the decrease in reflectance due to interference occurs in a narrow wavelength region and presents a sharp valley near the top of the peak, therefore, No longer a broadband multilayer film.

As disclosed in Non-Patent Document 3, a multilayer film having a laminated structure of film layers with different period lengths can obtain considerably high reflectance in a wide wavelength band. In this case, however, it is difficult to evaluate the structure. Generally, as a method for evaluating the structure of a multilayer film, small-angle scattering of X-rays is used and the period thereof is evaluated from the measured peak angle.

Fig. 25 is a graph showing the expected diffraction peak shape when the X-ray diffraction intensity angular distribution is changed. Figure 25 (A) shows the diffraction peak shape of a multilayer film with a periodic structure, Figure 25 (B) shows the diffraction peak shape of a multilayer film with an inhomogeneous periodic structure, and Figure 25 (C) shows that an additional layer (in this example) is included is the diffraction peak shape of the multilayer film of silicon layer). In the figure, the horizontal axis represents the incident angle of the incident light, and the vertical axis represents the reflectance.

As shown in FIG. 25(A), in the case of a multilayer film having a periodic structure, the peak corresponding to the incident angle is sharp. On the other hand, in the case of the non-uniform periodic multilayer film reported as a broadband multilayer film (see Non-Patent Document 3) in which the period length is not uniform, as shown in Fig. 25(B), many Irregularly shaped peaks, and the evaluation of the periodic length of multilayer films is difficult.

In contrast, according to the present invention, only additional layers are added to the periodic structure of the multilayer film, as shown in Fig. 25(C), resulting in a sharp diffraction peak, which makes the evaluation of the period length of the multilayer film easy . Note that it is not possible to directly measure the thickness of the additional layer, however, it is possible to control the thickness of the additional layer according to the invention. Specifically, it is possible to control the thickness of the additional layer by adjusting the film formation time based on the film thickness formed from the substance used for the additional layer per unit time (film formation rate) in the film formation work, from the The evaluation of the period length of the periodic structure part and the time required for film formation yields the film formation rate.

Likewise, in the present invention, the number of layer pairs of the deep layer group is half or less than the number of layer pairs of the surface layer group. As mentioned above, when the multilayer film is closer to the substrate side than the additional layer, the reflectance near the reflectance peak decreases compared to when only the surface film layer group is present. Here, since the number of layer pairs of the deep film layer group is half or less than that of the surface film layer group, the decrease in reflectance is small, and the shape of the reflectance peak is flat or slightly concave at the front end. It is unlikely that the portion near the reflectance peak becomes a sharp and deep valley.

Fig. 26 is a graph showing the change in the shape of the reflectance peak of the Mo/Si multilayer film when the number of layer pairs of the deep layer group changes. In the figure, the horizontal axis represents the wavelength of incident light, and the vertical axis represents the reflectance. In the example of Figure 26, the additional layer is silicon. The solid line (i), dotted line (ii) and dotted line (iii) in the figure respectively indicate that when the surface film group has 20 pairs of film layers, and the deep film layer group has 4 pairs of film layers and 2 pairs of film layers respectively And the reflectivity when 12 pairs of film layers.

It can be seen from Fig. 26 that in the case of (ii) where the surface coating layer group is 20 pairs of film layers and the deep layer layer group is 2 pairs of film layers, the reflectance peak is not flat enough and has a sharp point. However, in the deep layer group In the case of (i) where the number of layer pairs increases to 4 pairs of film layers, the reflectivity peak is flat. In addition, in the case of (iii) where the number of layer pairs of the deep film layer group is increased to 12 pairs of film layers, a deep valley is formed on the top of the reflectance peak and a flat shape cannot be obtained. Therefore, it is preferred that the number of layer pairs of the deep layer group is at least half or less than the number of layer pairs of the surface layer group. As described above, according to the present invention, it is possible to obtain a reflectance peak having a wide half width and a flat peak.

Also, in the above-mentioned second and third forms of multilayer film mirrors, silicon (Si), boron (B) or substances containing them can be used to form additional layers. When the wavelength is 13.5nm, the extinction coefficient k of silicon (Si) and boron (B) is quite small, as

k(Si)=0.0018, and

k(B) = 0.0041.

The role of the additional layer is to change the phase of the reflected light in the deep layer group and the surface layer group by 1/2 wavelength. Therefore, it is preferable to make the absorption as possible by using these substances or substances containing these substances (such as B ₄ C). The ground is small and obtains high reflectivity.

According to a fourth embodiment of the present invention, the multilayer mirror has a reflective multilayer film in which high refractive index film layers and low refractive index film layers for EUV rays are alternately laminated. This multilayer film mirror has the following features. First, it has a multilayer film group on the side of the light incident plane (surface film layer group), an additional layer on the side of the surface film layer group opposite the incident plane, and a multilayer film group on the side opposite the incident plane of the additional layer (deep layer group). Second, in the multilayer film group (first surface film group) on the incident plane side of the surface film group, the low-refractive index film layer is composed of a substance including molybdenum (Mo), and the high-refractive index film layer is composed of Composition of substances including silicon (Si). Third, in the multilayer film group (second surface film layer group) on the additional layer side of the surface film layer group, the low-refractive index film layer is composed of a substance including ruthenium (Ru), and the high-refractive index film layer is composed of Composition of substances including silicon (Si). Fourthly, in the deep layer group, the low-refractive-index layer is composed of ruthenium (Ru), and the high-refractive-index layer is composed of silicon (Si).

According to the above-mentioned fourth embodiment, a multilayer film composed of molybdenum and silicon is formed on a multilayer film having a structure in which additional layer. Even Ru/Si multilayers with a periodic structure can have a wider half-width than Mo/Si multilayers, and even multilayers with additional layers can have wider half widths than Mo/Si multilayers. The wider half-width of the . By forming a Mo/Si film layer on it, the peak reflectivity can be increased and a wider half width can be obtained.

According to a fifth embodiment of the present invention, a multilayer film mirror has a reflective multilayer film in which a high-refractive-index film layer and a low-refractive-index film layer are maintained under the condition that the Bragg reflection condition maintains Alternate lamination on a substrate: Reflected rays from multiple interfaces of high-refractive-index layers and low-refractive-index layers are made in-phase for EUV rays. This multilayer film mirror has the following features. First, it includes an insertion layer having a thickness of half or more of the center wavelength of EUV rays. Second, the EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is broadened.

According to the above-mentioned fifth embodiment, a part of a pair of high-refractive-index film layers and low-refractive-index film layers (film layer pair) is composed of two substances, and another part may be composed of three or more substances.

In addition, in the fifth embodiment, the reflective multilayer film may include a plurality of film blocks in which the high refractive index film layer H and pairs of low refractive index film layers L1 and L2 of different structures are repeatedly laminated. For example, it may include L1/L2/L1/H film layer pairs repeatedly stacked film layer blocks and L1/H film layer pair stacked film layer blocks repeatedly, and the number of film layer layer stacking repetitions in each film layer block can be 1 -50. In this case, the film layers included in each film layer pair may have different thicknesses. Note that it is assumed that the film layer constituent substances of L1 and L2 are different from each other (this also applies below). In addition, in the fifth embodiment, it is also possible to independently change the thickness of each film layer while performing lamination, and set the reflectivity to 45% or above for light with a wavelength of 13.1 nm to 13.9 nm.

According to a sixth embodiment of the present invention, a multilayer film mirror has a reflective multilayer film in which a high-refractive-index film layer and a low-refractive-index film layer are maintained under the condition that the Bragg reflection condition maintains Alternate lamination on a substrate: Reflected rays from multiple interfaces of high-refractive-index layers and low-refractive-index layers are made in-phase for EUV rays. This multilayer film mirror has the following features. First, the reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 of different structures (layer pairs) are repeatedly laminated. Second, the film layer on the base side of the multilayer mirror is formed by repeated lamination of L2/H film layers, and the second film layer from the base is formed by repeated lamination of L2/L1/H film layers, The third film layer block from the base is formed by repeated stacking of the L1/H film layer pair, the fourth film layer block from the base is formed by repeated stacking of the L1/L2/L1/H film layer pair, and the fifth film block from the base The film layer block is formed by repeated lamination of L2/L1/H film layer pair, the sixth film layer block from the base is formed by repeated lamination of L1/H film layer pair, and the seventh film layer block from the base is formed by L1/L2/ The L1/H film layer pair is repeatedly stacked, and the eighth film layer block starting from the base is formed by repeated stacking of the L1/H film layer pair. Thirdly, the number of stacking repetitions of film layer pairs in each film layer block is 1-50. Fourth, the EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened.

Here, the EUV ray wavelength having a relatively high EUV ray reflectance means that the wavelength is within the range including the maximum reflectance and the flat part (almost constant reflectance) in the graph, and the horizontal axis in the graph represents wavelength, and the vertical axis represents the reflectance. For example, in the case of the solid line (i) in FIG. 26 above, the range is a wavelength of about 13.2-13.6 nm. Preferably, the wavelength range including the ideal wavelength (such as 13.5 nm) is within 0.5 nm, more preferably within 0.60 nm, where the reflectance is 50% or more, and the shape of the reflectance peak is flat (reflectance fluctuations within ± 5% ).

Here, the incident angle with a relatively high EUV ray reflectance means that the angle is within the range including the maximum reflectance and the flat part (almost constant reflectance) in the graph, and the horizontal axis in the graph represents the incident angle. angle, and the vertical axis represents the reflectivity. Note that in the sixth embodiment, it is preferable that the reflectance for glancing rays incident at an incident angle in the range of at least 18 degrees to 25 degrees is 50% or more. Ideal angles (such as 20 degrees) included within the range of angles of incidence of 0-25 degrees are preferably within 5 degrees of incidence, more preferably within 7 degrees of the range of incidence angles, wherein the reflectivity is 50% or more , and the shape of the reflectance peak is flat (the reflectance fluctuation is within ±5%).

According to a seventh embodiment of the present invention, the multilayer film mirror has a reflective multilayer film in which the high-refractive-index film layer and the low-refractive-index film layer are maintained under the condition that the Bragg reflection condition maintains Alternate lamination on a substrate: Reflected rays from multiple interfaces of high-refractive-index layers and low-refractive-index layers are made in-phase for EUV rays. This multilayer film mirror has the following features. First, the reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the pairs of low refractive index film layers L1 and L2 of different structures are repeatedly laminated. Second, the film layer on the base side of the multilayer mirror is formed by repeated lamination of L2/H film layers, and the second film layer from the base is formed by repeated lamination of L2/L1/H film layers, The third film layer starting from the base is formed by repeated stacking of the L1/H film layer pair, the fourth film layer starting from the base is formed by repeated stacking of the L2/L1/H film layer pair, and the fifth film layer starting from the base The block is formed by repeated stacking of L1/L2/L1/H film layer pairs, the sixth film layer block from the base is formed by repeated stacking of L1/H film layer pairs, and the seventh film layer block from the base is formed by L1/L2/ The L1/H film layer pair is repeatedly stacked, and the eighth film layer block starting from the base is formed by repeated stacking of the L1/H film layer pair. Thirdly, the number of stacking repetitions of film layer pairs in each film layer block is 1-50. Fourth, the EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened.

According to the seventh embodiment of the present invention, it is possible to make the reflectance uniform over the entire reflective surface by autonomously changing the total film thickness of the reflective multilayer film according to the incident angle of light at each site on the reflective surface. In addition, in the seventh embodiment, it is possible to set the value for the angle in the range of at least 0 to 20 degrees by changing the total film thickness of the reflective multilayer film while maintaining the film thickness ratio of each layer in the reflective multilayer film. The reflectance of glancing rays at the angle of incidence is 50% or greater.

According to an eighth embodiment of the present invention, a multilayer film mirror has a reflective multilayer film in which a high-refractive-index film layer and a low-refractive-index film layer are maintained under the condition that the Bragg reflection condition maintains Alternate lamination on a substrate: Reflected rays from multiple interfaces of high-refractive-index layers and low-refractive-index layers are made in-phase for EUV rays. This multilayer film mirror has the following features. First, the reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the pairs of low refractive index film layers L1 and L2 of different structures are repeatedly laminated. Second, the film block on the base side of the multilayer mirror is formed by repeated lamination of the L1/L2/L1/H film layer pair, and the second film block from the base is formed by the L2/L1/H film layer pair It is formed by repeated lamination. The third film block starting from the base is formed by repeated stacking of the L1/L2/L1/H film layer pair, and the fourth film block starting from the base is formed by repeated stacking of the L2/L1/H film layer pair. The fifth film block starting from the base is formed by repeated stacking of the L1/H film layer pair, the sixth film block starting from the base is formed by repeated stacking of the L1/L2/L1/H film layer pair, and the seventh film block starting from the base The film layer block is formed by repeated lamination of L2/L1/H film layer pair, the eighth film layer block from the base is formed by repeated lamination of L1/L2/L1/H film layer pair, and the ninth film layer block from the base is formed by The L1/H film layer pair is repeatedly stacked, the tenth film layer block from the base is formed by repeated stacking of the L1/L2/L1/H film layer pair, and the eleventh film layer block from the base is formed by L2/L1/H Layer pairs are repeatedly stacked, the twelfth film layer block from the base is formed by repeated layering of the L1/L2/L1/H film layer pair, and the thirteenth film layer block from the base is formed by the L1/H film layer pair Repeated layer formation. Thirdly, the number of stacking repetitions of film layer pairs in each film layer block is 1-50. Fourth, the EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. According to the eighth embodiment of the present invention, it is preferable that the reflectivity for glancing rays incident at an incident angle in the range of at least 0-20 degrees is 45% or above.

According to a ninth embodiment of the present invention, the multilayer film mirror has a reflective multilayer film in which the high refractive index film layer and the low refractive index film layer are maintained under the condition that the Bragg reflection condition is maintained Alternate lamination on a substrate: Reflected rays from multiple interfaces of high-refractive-index layers and low-refractive-index layers are made in-phase for EUV rays. This multilayer film mirror has the following features. First, the reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 of different structures (layer pairs) are repeatedly laminated. Second, the film layer on the base side of the multilayer mirror is formed by repeated lamination of L2/H film layers, and the second film layer from the base is formed by repeated lamination of L2/L1/H film layers, The third film layer starting from the base is formed by repeated stacking of the L2/H film layer pair, the fourth film layer starting from the base is formed by repeated stacking of the L1/H film layer pair, and the fifth film layer starting from the base is formed by L2/H film layer pair is repeatedly stacked, the sixth film layer block from the base is formed by repeated stacking of L2/L1/H film layer pair, and the seventh film layer block from the base is repeatedly stacked by L1/H film layer pair Formation, the eighth film layer block from the base is formed by repeated stacking of the L2/L1/H film layer pair, the ninth film layer block from the base is formed by repeated stacking of the L1/H film layer pair, and the tenth film layer block from the base is formed by repeated stacking The film layer block is formed by repeated lamination of L2/L1/H film layer pair, the eleventh film layer block from the base is formed by repeated lamination of L1/H film layer pair, and the twelfth film layer block from the base is formed by L2/ The L1/H film layer pair is repeatedly stacked, the thirteenth film layer block from the base is formed by the L1/L2/L1/H film layer pair, and the fourteenth film layer block from the base is formed by L1/H Membrane pairs are stacked repeatedly. Thirdly, the number of stacking repetitions of film layer pairs in each film layer block is 1-50. Fourth, the EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. According to this ninth embodiment, it is preferable that the reflectance for light having a wavelength of 13.1-13.9 nm is 45% or more.

According to a tenth embodiment of the present invention, the multilayer film mirror has a reflective multilayer film in which the high refractive index film layer and the low refractive index film layer are maintained under the condition that the Bragg reflection condition is maintained Alternate lamination on a substrate: Reflected rays from multiple interfaces of high-refractive-index layers and low-refractive-index layers are made in-phase for EUV rays. This multilayer film mirror has the following features. First, the reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 of different structures (layer pairs) are repeatedly laminated. Second, the film block on the base side of the multilayer mirror is formed by repeated stacking of H film layers, the second film block from the base is formed by repeated stacking of L2/H film pairs, and the The third film layer block is formed by repeated lamination of the L2/L1/H film layer pair. Thirdly, the number of stacking repetitions of film layer pairs in each film layer block is 1-50. Fourth, the EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened.

According to an eleventh embodiment of the present invention, the multilayer film mirror has a reflective multilayer film in which the high refractive index film layer and the low refractive index film layer are maintained under the condition that the Bragg reflection condition maintains The layers are stacked alternately on the substrate: the reflected light rays from multiple interfaces of the high-refractive index film layer and the low-refractive index film layer are made in-phase for EUV rays. This multilayer film mirror has the following features. First, at least one of the high-refractive index film layers has a thickness of half or more of the center wavelength of EUV rays. Second, the EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is broadened.

The exposure apparatus of the present invention is an exposure apparatus for forming a pattern by selectively irradiating a sensitive substrate with EUV rays, and arranging the above-mentioned multilayer film mirror in an optical system. According to the exposure apparatus of the present invention, the multilayer film having a wide wavelength band is formed at least at a part of the projection optical system and the illumination optical system, and therefore, it is possible to make the illumination on the image forming surface and the amount of light in the pupil uniform, and to maintain a high Image forming performance. In addition, it is possible to prevent a decrease in the amount of light caused by an alignment error of a mirror having a large period length in-plane distribution in the projection optical system.

With the multilayer film reflector of the present invention, a relatively high reflectivity and a reflectivity peak performance with a wide half-width can be obtained. Since a multilayer film having a wide spectral reflectance half-width has a small reflectance dependence on incident angle, according to the present invention, high image forming performance can be maintained in a projection optical system.

Since the exposure apparatus of the present invention uses such a multilayer film mirror, it is possible to make the illumination on the image forming surface and the amount of light in the pupil uniform and maintain high image forming performance.

Description of drawings

1 is a cross-sectional view showing a multilayer film mirror according to a first embodiment of the present invention;

Fig. 2 is a graph showing the relationship between the reflectivity calculation value and the wavelength of incident light of the multilayer film reflector according to the first embodiment of the present invention;

3 is a graph showing the relationship between the calculated reflectance value of the multilayer film mirror and the angle of incidence of incident light according to the first embodiment of the present invention;

4 is a cross-sectional view showing a multilayer film mirror according to a second embodiment of the present invention;

Fig. 5 is the graph that represents the calculated value of the reflectivity of the multilayer film reflector according to the second embodiment of the present invention, wherein (A) represents the dependence on the wavelength of the incident light, and (B) represents the dependence on the angle of incidence of the incident light dependency relationship;

6 is a cross-sectional view showing a multilayer film mirror according to a third embodiment of the present invention;

Fig. 7 is the graph that represents the calculated value of the reflectivity of the multilayer film reflector according to the third embodiment of the present invention, wherein (A) represents the dependence on the wavelength of the incident light, and (B) represents the dependence on the incident angle of the incident light dependency relationship;

8 is a cross-sectional view showing a multilayer film mirror according to a fourth embodiment of the present invention;

Fig. 9 is the graph that represents the reflectivity calculated value of the multilayer film reflector according to the fourth embodiment of the present invention, wherein (A) represents the dependence on the wavelength of the incident light, and (B) represents the dependence on the incident angle of the incident light dependency relationship;

Fig. 10 is a graph showing the dependence of the reflectivity of the multilayer mirror according to the fifth embodiment of the present invention on the angle of incidence;

Fig. 11 is a graph showing the dependence of the reflectivity of the multilayer film mirror on the incident angle according to the sixth embodiment of the present invention;

Fig. 12 is a graph showing the dependence of the reflectivity of the multilayer mirror according to the sixth embodiment of the present invention on the angle of incidence;

Fig. 13 is a graph showing the dependence of the reflectivity of the multilayer mirror according to the seventh embodiment of the present invention on the angle of incidence;

Fig. 14 is a graph showing the spectral reflectance performance of the multilayer film reflector according to the eighth embodiment of the present invention;

Fig. 15 is a graph showing the spectral reflectance performance of the multilayer film mirror according to the ninth embodiment of the present invention;

Fig. 16 is a graph showing the spectral reflectance performance of the multilayer film mirror according to the tenth embodiment of the present invention;

Fig. 17 is a graph showing the dependence of the reflectance of the multilayer mirror according to the seventh embodiment of the present invention on the angle of incidence;

18 is a schematic diagram showing an exposure apparatus according to an embodiment of the present invention;

Fig. 19 is a graph illustrating the dependence of the reflectivity of a conventional multilayer film mirror on the angle of incidence;

Figure 20 is a graph illustrating the spectral reflectance performance of a conventional multilayer film mirror;

Figure 21 shows a view of an optical system configured with six mirrors;

Fig. 22 (A) is the graph that represents the incident wavelength performance of the theoretical reflectivity of Mo/Si multilayer film and Ru/Si multilayer film, (B) is to represent half width and reflectivity peak for the Ru/Si multilayer film Mo/Si multilayer film is formed on the film so that the Mo/Si multilayer film in the multilayer film formed is a graph of the variation of the logarithm of the film layer;

Figure 23 shows the shape of the reflectance peak when the thickness of the additional layer (silicon layer) varies with the period length of the Mo/Si multilayer film;

Figure 24 is a schematic structural view of the calibrator;

Fig. 25 is a graph showing the expected diffraction peak shape when the angular distribution of X-ray diffraction intensity is changed, where (A) represents the case of a periodic structure multilayer film, (B) represents the case of an inhomogeneous periodic structure, and (C) Indicates the case of multilayer films including additional layers;

Fig. 26 is a graph showing changes in the reflectance peak shape of a Mo/Si multilayer film when the layer logarithm of the deep layer group changes.

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings.

Example 1

FIG. 1 is a cross-sectional view of a multilayer film mirror according to a first embodiment of the present invention. The substrate 1 is made of low thermal expansion glass polished to a surface roughness of 0.2 nm RMS or less. Twenty pairs of Ru/Si multilayer films 3 are formed on the surface of the substrate 1 , and five pairs of Mo/Si multilayer films 5 are formed on the Ru/Si multilayer films 3 . The period length of the Ru/Si multilayer film 3 (the thickness of the unit periodic structure (layer pair) of Ru/Si, represented by d ₁₁ in the figure) is 6.86nm, while the period length of the Mo/Si multilayer film 5 (The thickness of the Mo/Si layer pair, represented by d ₁₂ in the figure) was 6.9 nm. The Γ value of these multilayer films in each unit periodic structure is 0.4. Note that the Γ value is the ratio of the thickness of the Ru layer or Mo layer (d _Ru or d _Mo ) to the period length (d) of the multilayer film (Γ = d _Ru /d or Γ = d _Mo /d).

Here, a method of manufacturing a multilayer film in this example will be described. First, the surface of the substrate 1 made of low thermal expansion glass is polished until the roughness is 0.2 nm RMS or less. Next, 20 pairs of Ru/Si multilayer films 3 were formed on the surface of the substrate 1 by magnetron sputtering. Then, five pairs of Mo/Si multilayer films 5 were formed on the surface of the Ru/Si multilayer film 3 by magnetron sputtering.

2 and 3 are graphs showing calculated reflectance values of the multilayer film mirror according to the present embodiment. 2(A) and 2(B) show the relationship with the wavelength of incident light, and FIG. 3(A) and FIG. 3(B) show the relationship with the incident angle of incident light. The horizontal axis in FIG. 2 represents the wavelength of incident light. The horizontal axis in FIG. 3 represents the incident angle (hereinafter, the incident angle refers to the angle formed by the incident light and the normal line of the reflective surface). In both figures, the vertical axis represents the reflectivity of the multilayer film, and the solid line (i) represents the multilayer film (deep film layer side: 20 pairs of Ru/Si film layers, surface film layer side: 5 pairs of Mo/Si film layers layer) reflectivity. The dotted line (ii) in FIG. 2(A) and FIG. 3(A) and the dotted line (iii) in FIG. 2(B) and FIG. 3(B) are comparative examples. Comparative example (ii) shows the reflectance of 26 pairs of Ru/Si multilayer film, and comparative example (iii) shows the reflectance of 27 pairs of Mo/Si multilayer film.

As shown in FIG. 2(A), the peak reflectance of the multilayer film (i) in this embodiment is 69.7%, and the half width is 0.86 nm. In contrast, in Comparative Example (ii) (26 pairs of Ru/Si multilayer film), as in Example (i), the full width at half width is 0.86nm, however, the peak reflectance is as low as 67.4%, which is low. 2% or more. In addition, as shown in FIG. 2(B), in Comparative Example (iii) (27 pairs of Mo/Si multilayer film), the peak value is about 70.0%, which is basically the same as that of this Example (i), however, The half width is 0.72nm, which is narrower by 0.1nm or more. As described above, by forming a Mo/Si multilayer film on a Ru/Si multilayer film, a high peak reflectance and a wide half width can be obtained.

As shown in Figure 3(A), the multilayer film (i) in this example is similar to the comparative example (ii) in that the reflectance is maximum and almost constant in the range of incident angles from 0° to 10°, while the peak reflectance The ratio is higher than that in Comparative Example (ii). In addition, as shown in Fig. 3(B), the peak reflectance of the multilayer film (i) in this example is higher than that in the comparative example (iii), and the peak reflectance is higher than that in the range of the incident angle in which the constant The one in (iii) is wider. As described above, in the present embodiment, it is possible to obtain almost constant reflectance over a wide range of incident angles.

Note that the cycle length mentioned in this embodiment is just an example, and the cycle length can be adjusted according to the target wavelength to be used. In addition, in this embodiment, the multilayer film is formed by magnetron sputtering, however, the method for forming the film is not limited thereto, and the film can be formed by ion beam sputtering or vacuum deposition. In this embodiment, the Γ value of the multilayer film is set to 0.4, however, the Γ value is not limited thereto, and the Γ value on the substrate can be increased to eg about 0.5 if the periodic structure is controllable. In this case, high reflectance can be obtained (see the above-mentioned Non-Patent Document 4).

Example 2

Fig. 4 is a schematic cross-sectional view of a multilayer mirror according to a second embodiment of the present invention. The substrate 10 is made of low thermal expansion glass polished to a surface (top surface in the figure) roughness of 0.2 nm RMS or less. Four pairs of Mo/Si multilayer films (deep film layer group) 11 are formed on the surface of the substrate 10 . The period length of the Mo/Si multilayer film 11 (the thickness of the Mo/Si film layer pair) was 6.9 nm, and the Γ value was 0.5.

On the surface of the Mo/Si multilayer film 11 is formed an additional layer 12 (a silicon layer in this embodiment). The thickness of the additional layer 12 is adjusted so as to have an optical thickness of about 1/4 of the wavelength of the incident light. In this embodiment, the thickness of the additional layer 12 is about 3.5 nm. In addition, on the surface of the additional layer 12, 20 pairs of Mo/Si multilayer films (surface film layer groups) 13 having a period length of 6.9 nm and a Γ value of 0.4 were formed. In addition, the surface film layer group 13 and the deep film layer group 11 are further simplified in the figure.

FIG. 5 is a graph showing calculated reflectance values of the multilayer film mirror according to the present embodiment. FIG. 5(A) shows the relationship with the wavelength of the incident light, and FIG. 5(B) shows the relationship with the incident angle of the incident light. The horizontal axis in FIG. 5(A) represents the wavelength of incident light, and the horizontal axis in FIG. 5(B) represents the incident angle. The vertical axes in both graphs represent calculated values of reflectance. The solid line (w1) in the figure shows the reflectance of the multilayer film mirror in this example, and the dotted line (C) shows the comparative example. Comparative Example (C) shows the reflectance of 40 pairs of Mo/Si multilayer films.

As shown in FIG. 5(A), the half width of the reflectance peak (w1) of the multilayer film in this example is 0.9 nm or more. In addition, the shape of the reflectance peak ( w1 ) in this embodiment is flat at the top, and the reflectance is almost constant at about 52% in the wavelength range of 13.2-13.7 nm. When compared with Comparative Example (C), the peak value (w1) of the reflectance of the multilayer film in this example does not coincide with that of Comparative Example (C) of the simple periodic structure multilayer film, however, it is known that in a wide Consistent reflectivity over the wavelength range is very advantageous.

As shown in FIG. 5(B), the reflectance (w1) of the multilayer film in this example is almost constant over a wide range of incident angles from 0° to about 13°. In contrast, in Comparative Example (C), the incident angle range at which the reflectance is almost constant is 0° to about 7°. In the present example, the incident angle range where the reflectance is constant is significantly wider than that in the comparative example (C). Therefore, according to the present embodiment, the dependence of the reflectance on the angle of incidence is significantly reduced, and it is known that high reflectance can be obtained in a wide range of angles of incidence.

Supplementary conditions of Embodiment 2 will be described below. In this embodiment, the Γ value of the multilayer film varies between the top and bottom of the additional layer 12, however, the invention is not limited thereto, for example, the Γ value may be the same. In addition, in this embodiment, silicon is used as the material of the additional layer 12, however, the material of the additional layer is not limited to silicon. As the additional layer material, in addition to silicon, boron (B), Mo, and Ru whose absorption is small in the EUV region, or carbon tetraboride (B ₄ C), silicon carbide (SiC), etc. containing these substances are preferable. . Other substances can also be used if a slight decrease in reflectivity does not cause serious problems. However, even in the case of using any of these substances, it is necessary to make the optical thickness of the additional layer 12 approximately 1/4 of the wavelength of incident light (approximately half the period length of the multilayer film) or this thickness plus Integer multiples of the cycle length. The above supplementary situation also applies to Examples 3 and 4.

In this embodiment, the additional layer 12 is sandwiched to form 4 pairs of film layers on the base side and 20 pairs of film layers on the incident side, however, the number of film layer pairs is not limited thereto. According to the purpose of use, the logarithm of the film layer can be changed to obtain sufficient reflectivity or uniform reflectivity.

Example 3

Fig. 6 is a schematic cross-sectional view of a multilayer film mirror according to a third embodiment of the present invention. The substrate 20 is made of low thermal expansion glass polished to a surface (top surface in the figure) with a roughness of 0.2 nm RMS or less. Five pairs of Ru/Si multilayer films (deep film layer group) 21 are formed on the surface of the substrate 20 . The period length of the Ru/Si multilayer film 21 (the thickness of the Ru/Si film layer pair) is 6.9 nm, and the Γ value is 0.5.

On the surface of the Ru/Si multilayer film 21 is formed an additional layer 22 (a silicon layer in this embodiment). The thickness of the additional layer 22 is adjusted to have an optical thickness of about 1/4 of the wavelength of the incident light. In this embodiment, the thickness of the additional layer 22 is about 3.85 nm. In addition, on the surface of the additional layer 22, 20 pairs of Ru/Si multilayer films (surface film layer groups) 23 having a period length of 6.96 nm and a Γ value of 0.4 were formed.

FIG. 7 is a graph showing calculated reflectance values of the multilayer film mirror according to the present embodiment. FIG. 7(A) shows the relationship with the wavelength of the incident light, and FIG. 7(B) shows the relationship with the incident angle of the incident light. The horizontal axis in FIG. 7(A) represents the wavelength of incident light, and the horizontal axis in FIG. 7(B) represents the incident angle. The vertical axes in both graphs represent calculated values of reflectance. The solid line (w2) in the figure represents the reflectance of the multilayer film mirror in this example, and the dotted line (C) represents the comparative example. Comparative Example (C) shows the reflectance of 40 pairs of Mo/Si multilayer films.

As shown in FIG. 7(A), the half width of the reflectance peak (w2) of the multilayer film in this example is 1.0 nm or more. In addition, the shape of the reflectance peak (w2) in this embodiment is flat at the top, and the reflectance is almost constant at about 60% in the wavelength range of 13.2-13.7 nm. When compared with Comparative Example (C), the peak value (w2) of reflectance of the multilayer film in this example does not coincide with that of Comparative Example (C) of the simple periodic structure multilayer film, however, it is known that in a wide Consistent reflectivity over the wavelength range is very advantageous.

As shown in FIG. 7(B), the reflectance (w2) of the multilayer film in this example is almost constant over a wide range of incident angles from 0° to about 13°. In contrast, in Comparative Example (C), the incident angle range at which the reflectance is almost constant is 0° to about 7°. Therefore, in the present example, the incident angle range where the reflectance is constant is significantly wider than that in the comparative example (C). Thus, according to the present embodiment, the dependence of the reflectance on the angle of incidence is significantly reduced, and it is known that high reflectance can be obtained in a wide range of angles of incidence.

Note: In this embodiment, the additional layer 22 is sandwiched to form 5 pairs of film layers on the base side and 20 pairs of film layers on the incident side, however, the number of film layer pairs is not limited thereto. According to the purpose of use, the logarithm of the film layer can be changed to obtain sufficient reflectivity or uniform reflectivity.

Example 4

Fig. 8 is a schematic cross-sectional view of a multilayer film mirror according to a fourth embodiment of the present invention. The substrate 30 is made of low thermal expansion glass polished to a surface (top surface in the figure) with a roughness of 0.2 nm RMS or less. Five pairs of Ru/Si multilayer films (deep film layer group) 31 are formed on the surface of the substrate 30 . The period length (thickness of the Ru/Si film layer pair) of the Ru/Si multilayer film 31 is 6.96 nm, and the Γ value is 0.5.

On the surface of the Ru/Si multilayer film 31, an additional layer 32 (a silicon layer in this embodiment) is formed. The thickness of the additional layer 32 is adjusted to have an optical thickness of about 1/4 of the wavelength of the incident light. In this embodiment, the thickness of the additional layer 32 is about 3.75 nm. In addition, on the surface of the additional layer 32, 16 pairs of Ru/Si multilayer films (second surface film layer group) 33 having a period length of 6.96 nm and a Γ value of 0.4 are formed, and on the surface of the Ru/Si layer 33 Sixteen pairs of Mo/Si multilayer films (first surface film layer group) 34 having a period length of 6.9 nm and a Γ value of 0.4 were formed.

FIG. 9 is a graph showing calculated reflectance values of the multilayer film mirror according to the present embodiment. FIG. 9(A) shows the relationship with the wavelength of the incident light, and FIG. 9(B) shows the relationship with the incident angle of the incident light. The horizontal axis in FIG. 9(A) represents the wavelength of incident light, and the horizontal axis in FIG. 9(B) represents the incident angle. The vertical axes in both figures represent the calculated reflectance values, the solid line (w3) represents the reflectance of the multilayer mirror in this embodiment, and the dotted line (C) represents the comparative example. Comparative Example (C) shows the reflectance of 40 pairs of Mo/Si multilayer films.

As shown in FIG. 9(A), the half width of the reflectance peak (w3) of the multilayer film in this example is 1.0 nm or more. In addition, the shape of the reflectance peak (w3) in this embodiment is flat at the top, and the reflectance is almost constant at about 62% in the wavelength range of 13.2-13.7 nm. When compared with Comparative Example (C), the peak value (w3) of reflectance of the multilayer film in this example does not coincide with that of Comparative Example (C) of a simple periodic structure multilayer film, however, it is known that Consistent reflectivity over the wavelength range is very advantageous.

As shown in FIG. 9(B), the reflectance (w3) of the multilayer film in this example is almost constant over a wide range of incident angles from 0° to about 10°, and the reflectance is up to about 15° incident angle. There was no significant decrease either. In contrast, in Comparative Example (C), the reflectance is almost constant in the range of incident angles from 0° to about 7°, and the reflectance drops sharply around the incident angle of about 10°. Therefore, in the present example, the incident angle range where the reflectance is constant is significantly wider than that in the comparative example (C). Thus, in this embodiment, the dependence of the reflectance on the angle of incidence is significantly reduced, and it is known that high reflectance can be obtained in a wide range of angles of incidence.

Note: In this embodiment, the additional layer 32 is sandwiched, forming 5 pairs of film layers on the substrate side and 21 (=16+5) pairs of film layers on the incident side, however, the number of film layer pairs is not limited thereto . According to the purpose of use, the logarithm of the film layer can be changed to obtain sufficient reflectivity or uniform reflectivity.

Example 5

Next, a multilayer film mirror according to a fifth embodiment of the present invention will be described. In the multilayer film of this embodiment, the material structure and film thickness of each film layer are optimized by using the Needle method so that for EUV rays (extreme ultraviolet rays) with a wavelength of 13.5 nm and an incident angle of 15° to 25°, Rays) can obtain uniform high reflectivity.

The multilayer film in this embodiment is formed on a finely polished synthetic silica glass substrate, which includes a plurality of film blocks in which film layer pairs (unit periodic structures) of different structures are repeatedly stacked . Here, the film layer pair (unit periodic structure) is a low-refractive-index film layer made of a substance with a low refractive index for EUV and a high-refractive-index film layer made of a substance with a high refractive index for EUV. A film layer structure of a film. In this embodiment, molybdenum (Mo) and ruthenium (Ru) are used as the low-refractive index film layer, and silicon (Si) is used as the high-refractive index film layer.

In addition, in the following description, the structure of a multilayer film is represented by the structure of a pair of film layers in each film layer block (unit periodic structure) and the logarithm (number of repetitions) of laminated film layers, and each Membrane segments are represented by counts from the base (Membrane segment A).

The structure of the multilayer film in this embodiment is shown in Table 1. The total thickness of the multilayer film in this example is about 450 nm. In addition, preferably, the thickness of each layer of the multilayer film is not constant, and the film thickness is adjusted according to the position of each layer of film on the multilayer film, so as to obtain ideal reflectance.

Table 1 A unit periodic structure repeat number 1 Ru/Si 3 2 Ru/Mo/Si 4 3 Mo/Si 6 4 Mo/Ru/Mo/Si 1 5 Ru/Mo/Si 4 6 Mo/Si 20 7 Mo/Ru/Mo/Si 14 8 Mo/Si 4 9 Mo 1

In Table 2, Table 3 and Table 4 below, the thickness of each film in the multilayer film of this example is shown. In these Tables, each layer of the multilayer film is represented by counts from the base side, and a preferable film thickness range (nm) and a more preferable film thickness (nm) of each layer are shown. Note that due to the large number of film layers of the multilayer film, this table is represented as a plurality of separate tables.

Table 2 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 12 RuSi 6～26～2 44 34 RuSi 6～26～2 44 56 RuSi 6～26～2 44 789 RuMoSi 5～22～06～2 314 101112 RuMoSi 4～12～06～2 214 131415 RuMoSi 4～12～06～2 214 161718 RuMoSi 3～13～16～2 224 1920 MoSi 5～26～2 34 2122 MoSi 4～16～2 twenty four 2324 MoSi 2～06～2 14 2526 MoSi 5～26～2 34 2728 MoSi 5～26～2 44 2930 MoSi 5～26～2 44 31323334 MoRuMoSi 2～02～03～16～2 1124 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 353637 RuMoSi 3～12～06～2 224 383940 RuMoSi 3～13～16～2 224 414243 RuMoSi 2～03～16～2 224 444546 RuMoSi 2～04～16～2 124 4748 MoSi 5～26～2 34 4950 MoSi 5～27～2 34 5152 MoSi 4～17～2 35 5354 MoSi 3～125～8 217 5556 MoSi 3～17～2 25 5758 MoSi 4～17～2 34 5960 MoSi 5～26～2 34 6162 MoSi 5～26～2 34 6364 MoSi 5～26～2 34 6566 MoSi 5～26～2 34 6768 MoSi 5～26～2 34

table 3 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 6970 MoSi 5～26～2 34 7172 MoSi 5～26～2 34 7374 MoSi 5～27～2 34 7576 MoSi 5～27～2 35 7778 MoSi 4～18～3 35 7980 MoSi 3～135～12 223 8182 MoSi 4～17～2 35 8384 MoSi 5～26～2 34 8586 MoSi 5～26～2 34 87888990 MoRuMoSi 2～02～03～16～2 1124 91929394 MoRuMoSi 2～03～12～06～2 1214 95969798 MoRuMoSi 2～03～12～06～2 1214 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 99100101102 MoRuMoSi 2～03～12～06～2 1214 103104105106 MoRuMoSi 2～03～12～06～2 1214 107108109110 MoRuMoSi 2～03～12～06～2 1214 111112113114 MoRuMoSi 2～03～12～06～2 1214 115116117118 MoRuMoSi 2～03～12～06～2 1214 119120121122 MoRuMoSi 2～03～12～06～2 1214 123124125126 MoRuMoSi 2～03～12～06～2 1224

Table 4 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 127128129130 MoRuMoSi 2～02～02～06～2 1224 131132133134 MoRuMoSi 2～02～03～16～2 1124 135136137138 MoRuMoSi 2～02～03～16～2 1124 139140141142 MoRuMoSi 2～02～03～16～2 1124 143144 MoSi 5～26～2 34 145146 MoSi 5～26～2 34 147148 MoSi 5～27～2 34 149150 MoSi 5～27～2 34 151 Mo 4～1 3

According to the table, the silicon film layers of the 54th and 80th layers from the base side are thicker than the other film layers (in the following description, these are referred to as extremely thick silicon film layers). The thickness of the extremely thick silicon film layer is half or more of the center wavelength of the EUV ray, and as an insertion layer, the EUV ray with a relatively high reflectivity of the EUV ray can be adjusted by adjusting the phase difference of the EUV ray reflected from the interface of each film layer. The wavelength range or angle of incidence becomes wider.

FIG. 10 is a graph showing the dependence of the reflectivity of the multilayer film mirror on the incident angle according to the present embodiment. In the figure, the horizontal axis represents the incident angle (degrees (°)) of light entering the multilayer mirror, and the vertical axis represents the reflectance (%) for EUV rays with a wavelength (λ) of 13.5 nm. As can be seen from the figure, in the multilayer film of this embodiment, a high reflectance of 50% or more can be obtained for EUV rays in a wide incident range (incidence angle is at least 18° to 25°). In particular, in the A1 region in the figure (incidence angle ranges from θ1 (18.4°) to θ2 (24.8°)), the reflectivity is almost constant at around 60%, and the reflectivity has almost no dependence on the incident angle. Therefore, the obtain high resolution.

Example 6

Next, a sixth embodiment of the present invention will be described. In the multilayer film of the present embodiment, the material structure and the total film thickness of each film layer are optimized while maintaining the film thickness ratio of each film layer, so that the wavelength is 13.5nm and the incidence of 0 ° to 20 ° Angular incident EUV rays can achieve high reflectivity. Using the multilayer film in the embodiment, by controlling the total film thickness of each part of the optical element, for example, a high reflectance is uniformly obtained over the entire reflective surface at different incident angles of light rays to each part in the same reflective surface .

The multilayer film in this example was formed by forming a multilayer film having the structure shown in Table 5 below on a finely polished synthetic silica glass substrate. Note that the total film thickness of the multilayer film in this embodiment is about 420 nm to 430 nm. In addition, preferably, the thickness of each layer of the multilayer film is not constant, and can be adjusted by changing the thickness according to the position on the multilayer film, so as to obtain an ideal reflectance.

table 5 A unit periodic structure repeat number 1 Ru/Si 4 2 Ru/Mo/Si 6 3 Mo/Si 5 4 Ru/Mo/Si 5 5 Mo/Ru/Mo/Si 2 6 Mo/Si 9 7 Mo/Ru/Mo/Si 19 8 Mo/Si 3 9 Mo 1

In Table 6, Table 7 and Table 8 below, the thickness of each film in the multilayer film of this example is shown. Note that due to the high number of film layers of multilayer films, this table is presented as separate tables. According to these tables, the 28th and 69th silicon layers from the base side are extremely thick silicon film layers.

Table 6 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 12 RuSi 9～36～2 64 34 RuSi 6～26～2 44 56 RuSi 6～26～2 44 78 RuSi 6～26～2 44 91011 RuMoSi 5～22～06～2 314 121314 RuMoSi 4～12～06～2 314 151617 RuMoSi 4～12～06～2 314 181920 RuMoSi 4～12～06～2 314 212223 RuMoSi 3～12～06～2 214 242526 RuMoSi 2～03～16～2 124 2728 MoSi 5～222～7 315 2930 MoSi 5～26～2 34 3132 MoSi 5～26～2 34 3334 MoSi 5～26～2 34 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 3536 MoSi 5～26～2 34 373839 RuMoSi 2～03～16～2 124 404142 RuMoSi 2～03～16～2 224 434445 RuMoSi 2～03～16～2 124 464748 RuMoSi 2～03～16～2 124 495051 RuMoSi 2～03～16～2 124 52535455 MoRuMoSi 2～02～03～16～2 1124 56575859 MoRuMoSi 2～02～04～16～2 1124 6061 MoSi 5～27～2 34 6263 MoSi 4～17～2 35 6465 MoSi 4～17～2 35 6667 MoSi 3～18～3 25

Table 7 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 6869 MoSi 2～036～12 124 7071 MoSi 3～17～2 25 7273 MoSi 4～16～2 34 7475 MoSi 5～26～2 34 7677 MoSi 5～26～2 34 78798081 MoRuMoSi 2～02～03～16～2 1124 82838485 MoRuMoSi 2～03～12～06～2 1224 86878889 MoRuMoSi 2～03～12～06～2 1214 90919293 MoRuMoSi 2～03～12～06～2 1214 94959697 MoRuMoSi 2～03～12～06～2 1214 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 9899100101 MoRuMoSi 2～03～12～06～2 1214 102103104105 MoRuMoSi 2～03～12～06～2 1214 106107108109 MoRuMoSi 2～03～12～06～2 1214 110111112113 MoRuMoSi 2～03～12～06～2 1214 114115116117 MoRuMoSi 2～03～12～06～2 1214 118119120121 MoRuMoSi 2～03～12～06～2 1214 122123124125 MoRuMoSi 2～03～12～06～2 1214

Table 8 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 126127128129 MoRuMoSi 2～02～02～06～2 1224 130131132133 MoRuMoSi 2～02～02～06～2 1124 134135136137 MoRuMoSi 2～02～03～16～2 1124 138139140141 MoRuMoSi 2～02～03～16～2 1124 142143144145 MoRuMoSi 2～02～03～16～2 1124 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 146147148149 MoRuMoSi 2～02～03～16～2 1124 150151152153 MoRuMoSi 2～02～03～16～2 1124 154155 MoSi 5～26～2 34 156157 MoSi 5～26～2 34 158159 MoSi 4～17～1 34 160 Mo 4～1 3

11 and 12 are graphs showing the dependence of the reflectance on the incident angle of the multilayer film mirror according to the present embodiment. In the figure, the horizontal axis represents the incident angle (degrees (°)) at which light enters the multilayer film mirror, and the vertical axis represents the reflectance (%) for EUV rays having a wavelength (λ) of 13.5 nm. The reflectance shown in FIGS. 11 and 12 was obtained from multilayer films whose total film thickness was varied while maintaining the ratio of film thickness per layer of the multilayer film. The film thicknesses shown in each figure are when the total film thickness of the multilayer film in Fig. 11(A) is assumed to be 1.000 and range from 1.000 (Fig. 11(A)) to 0.9650 (Fig. 12(G)) The value when changing at intervals of 0.0025.

The area A2 between the two vertical dotted lines in each figure represents the range of incident angles in which the dependence of the reflectivity on the incident angle is small. It can be seen from Fig. 11 and Fig. 12 that as the total film thickness increases, the area A2 moves to a larger incident angle (moves to the right of the figure). For example, when the area A2 is located within the incident angle range of about 4°-9° in FIG. 12(G), in FIG. 11(A) the range is about 17°-20°. Therefore, according to the present embodiment, by changing the total film thickness of the multilayer film, a high reflectance of 50% or more can be obtained in a wide incident angle range of 0°-20°.

Example 7

Next, a seventh embodiment of the present invention will be described. In the multilayer film of this embodiment, the material structure and film thickness of each film layer are optimized so as to obtain high reflectivity for EUV rays with a wavelength of 13.5 nm and passing through the entire incident light range from 0° to 20°. The multilayer film in this example was formed by forming a multilayer film having the structure shown in Table 9 below on a finely polished synthetic silica glass substrate. Note that the total film thickness of the multilayer film in this example is about 280 nm. In addition, preferably, the thickness of each layer of the multilayer film is not constant, and is adjusted according to the position on the multilayer film to change the thickness, so as to obtain ideal reflectance.

Table 9 A unit periodic structure repeat number 1 Mo/Ru/Mo/Si 3 2 Ru/Mo/Si 2 3 Mo/Ru/Mo/Si 1 4 Ru/Mo/Si 5 5 Mo/Si 3 6 Mo/Ru/Mo/Si 4 7 Ru/Mo/Si 1 8 Mo/Ru/Mo/Si 1 9 Mo/Si 3 10 Mo/Ru/Mo/Si 2 11 Ru/Mo/Si 1 12 Mo/Ru/Mo/Si 10 13 Mo/Si 1 14 Mo 1

Fig. 13 is a graph showing the dependence of the reflectivity of the multilayer film mirror according to the present embodiment on the incident angle. In the figure, the horizontal axis represents the incident angle (degrees (°)) at which light enters the multilayer film mirror, and the vertical axis represents the reflectance (%) for EUV rays having a wavelength (λ) of 13.5 nm. It can be seen from the figure that according to the multilayer film mirror of this embodiment, a high reflectivity of 45% or above (in more detail, 54% or above) can be obtained in the entire incident angle range of 0°-20°.

Example 8

Next, an eighth embodiment of the present invention will be described. In the multilayer film of this embodiment, the material structure and film thickness of each film layer are optimized so as to obtain a high reflectivity for vertically incident EUV rays (extreme ultraviolet rays) with a wavelength of 13.1-13.9 nm. The multilayer film in this example was formed by forming a multilayer film having the structure shown in Table 10 below on a finely polished synthetic silica glass substrate. Note that the total film thickness of the multilayer film in this example is about 360 nm. In addition, preferably, the thickness of each layer of the multilayer film is not constant, and is adjusted according to the position on the multilayer film to change the thickness, so as to obtain ideal reflectance.

Table 10 A unit periodic structure repeat number 1 Ru/Si 1 2 Ru/Mo/Si 1 3 Ru/Si 1 4 Mo/Si 2 5 Ru/Si 1 6 Ru/Mo/Si 5 7 Mo/Si 3 8 Ru/Mo/Si 5 9 Mo/Si 5 10 Ru/Mo/Si 4 11 Mo/Si 4 12 Ru/Mo/Si 12 13 Mo/Ru/Mo/Si 2 14 Mo/Si 1 15 Mo 1

In Table 11 and Table 12 below, the thickness of each film in the multilayer film of this example is shown. Note that due to the high number of film layers of multilayer films, this table is presented as separate tables. According to these tables, the 28th, 51st, 73rd and 75th silicon layers counted from the base side are extremely thick silicon film layers.

Table 11 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 12 RuSi 6～25～2 43 345 RuMoSi 5～22～05～2 313 67 RuSi 5～26～2 44 89 MoSi 8～37～2 65 1011 MoSi 6～25～2 43 1213 RuSi 5～25～2 34 141516 RuMoSi 4～12～05～2 314 171819 RuMoSi 4～12～05～2 314 202122 RuMoSi 3～12～05～2 224 232425 RuMoSi 2～03～15～2 224 262728 RuMoSi 2～04～112～4 128 2930 MoSi 2～06～2 14 3132 MoSi 5～25～2 34 3334 MoSi 5～26～2 34 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 353637 RuMoSi 2～03～16～2 124 383940 RuMoSi 2～03～16～2 224 414243 RuMoSi 2～03～16～2 124 444546 RuMoSi 2～03～16～2 124 474849 RuMoSi 2～04～16～2 124 5051 MoSi 4～124～8 316 5253 MoSi 2～07～2 14 5455 MoSi 5～25～2 34 5657 MoRu 5～25～2 34 5859 MoSi 5～26～2 44 606162 RuMoSi 2～03～16～2 124 636465 RuMoSi 2～03～16～2 124 666768 RuMoSi 2～03～16～2 124

Table 12 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 697071 RuMoSi 2～04～16～2 124 7273 MoSi 4～118～6 312 7475 MoSi 2～015～5 110 7677 MoSi 4～16～2 34 7879 MoSi 5～26～2 34 808182 RuMoSi 2～03～16～2 124 838485 RuMoSi 3～12～06～2 214 868788 RuMoSi 3～12～06～2 214 899091 RuMoSi 3～12～06～2 214 929394 RuMoSi 3～12～06～2 214 959697 RuMoSi 3～12～06～2 214 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 9899100 RuMoSi 3～12～06～2 214 101102103 RuMoSi 3～12～06～2 214 104105106 RuMoSi 3～12～06～2 214 107108109 RuMoSi 3～12～06～2 214 110111112 RuMoSi 3～12～06～2 214 113114115 RuMoSi 3～12～06～2 214 116117118119 MoRuMoSi 2～02～02～06～2 1214 120121122123 MoRuMoSi 2～02～02～06～2 1114 124125 MoSi 4～16～2 34 126 Mo 4～1 3

FIG. 14 is a graph showing the spectral reflectance performance of the multilayer film mirror according to this embodiment. In the figure, the horizontal axis represents the wavelength (nm) of the incident light, and the vertical axis represents the reflectance (%). Note that it assumes that the angle of incidence of the ray is 0° (normal incidence on the reflective surface). As can be seen from the figure, according to the multilayer film mirror of this embodiment, a high reflectivity of 45% or more (in more detail, 50% or more) can be obtained over the above-mentioned wide wavelength range.

Example 9

Next, a ninth embodiment of the present invention will be described. In the multilayer film of this embodiment, the material structure and film thickness of each film layer are optimized so as to obtain as high a reflectivity as possible for EUV rays with a wavelength of 13.5 nm and vertical incidence. The multilayer film in this example was formed by forming a multilayer film having the structure shown in Table 13 below on a finely polished synthetic silica glass substrate. Note that the total film thickness of the multilayer film in this example is about 510 nm. In addition, preferably, the thickness of each layer of the multilayer film is not constant, and is adjusted according to the position on the multilayer film to change the thickness, so as to obtain ideal reflectance.

Table 13 A unit periodic structure repeat number 1 Si 1 2 Ru/Si 17 3 Ru/Mo/Si 56 4 Ru/Mo 1

FIG. 15 is a graph showing the spectral reflectance performance of the multilayer film mirror according to this embodiment. In the figure, the horizontal axis represents the wavelength (nm) of the incident light, and the vertical axis represents the reflectance (%). Note that it assumes an angle of incidence of 0° (normal incidence on a reflective surface). It can be seen from the figure that according to the multilayer film mirror of this embodiment, for EUV rays with a wavelength of 13.5nm, a high reflectance of 70% or more (such as about 76%) higher than that in FIG. 20 can be obtained.

Example 10

Next, a tenth embodiment of the present invention will be described. In the multilayer film of this embodiment, the material structure and film thickness of each film layer are optimized so as to obtain a high reflectivity for EUV rays (extreme ultraviolet rays) with a wavelength of 13.5-14.2 nm at normal incidence. The multilayer film in this example is a Mo/Si multilayer film in which molybdenum layers (low refractive index layer) and silicon layers (high refractive index layer) are alternately stacked on a finely polished synthetic silica glass substrate.

Note that the total film thickness of the multilayer film in this example is about 330 nm. In addition, preferably, the thickness of each layer of the multilayer film is not constant, and is adjusted according to the position on the multilayer film to change the thickness, so as to obtain ideal reflectance. In Table 14 and Table 15 below, the thickness of each layer of the multilayer film in this example is shown. Note that due to the high number of film layers of multilayer films, this table is presented as separate tables. According to these tables, the 46th silicon layer (the silicon layer almost in the middle of the multilayer film) is an extremely thick silicon film layer.

Table 14 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 12 MoSi 20～56～2 114 34 MoSi 6～26～2 44 56 MoSi 6～26～2 43 78 MoSi 9～38～3 65 910 MoSi 7～26～2 43 1112 MoSi 6～26～2 44 1314 MoSi 6～26～2 44 1516 MoSi 6～26～2 44 1718 MoSi 6～26～2 44 1920 MoSi 6～26～2 44 2122 MoSi 6～26～2 44 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 2324 MoSi 6～26～2 34 2526 MoSi 12～36～2 74 2728 MoSi 6～26～2 34 2930 MoSi 6～26～2 44 3132 MoSi 6～26～2 44 3334 MoSi 6～26～2 44 3536 MoSi 6～26～2 44 3738 MoSi 6～26～2 44 3940 MoSi 6～26～2 34 4142 MoSi 6～26～2 34 4344 MoSi 6～28～2 35

Table 15 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 4546 MoSi 2～014～6 17 4748 MoSi 6～26～2 34 4950 MoSi 6～26～2 34 5152 MoSi 6～26～2 44 5354 MoSi 6～26～2 44 5556 MoSi 6～26～2 44 5758 MoSi 6～26～2 44 5960 MoSi 6～26～2 44 6162 MoSi 6～26～2 44 6364 MoSi 6～26～2 44 6566 MoSi 6～26～2 44 unit periodic structure Preferred film thickness range (nm) More preferred film thickness (nm) 6768 MoSi 6～26～2 34 6970 MoSi 6～26～2 34 7172 MoSi 6～26～2 34 7374 MoSi 6～26～2 34 7576 MoSi 6～26～2 34 7778 MoSi 6～26～2 34 7980 MoSi 6～26～2 34 8182 MoSi 6～27～2 34 8384 MoSi 6～26～2 34 8586 MoSi 5～16～2 33

FIG. 16 is a graph showing the spectral reflectance performance of the multilayer film mirror according to this embodiment. Note that it forms a multilayer film using an ion beam sputtering method. In the figure, the horizontal axis represents the wavelength (nm) of the incident light, and the vertical axis represents the reflectance (%). The angle of incidence of the ray is assumed to be 0° (normal incidence on the reflective surface). The solid line in Fig. 16 represents the wavelength performance of reflectivity when using sputtering gas and argon (Ar) gas to form a film layer, and the dotted line represents the wavelength performance of reflectance when using krypton (Kr) gas as a sputtering gas to form a film layer .

As can be seen from FIG. 16, according to the multilayer film mirror in this embodiment, a high reflectance of 45% or more can be obtained in the above-mentioned wide wavelength range. In addition, when the Kr gas layer is formed as shown by the dotted line, the reflectance peak is larger and the half width of the spectral reflectance is wider than when the Ar gas layer is formed as shown by the solid line.

FIG. 17 is a graph showing the dependence of the reflectivity of the multilayer film mirror according to this embodiment on the incident angle. In the figure, the horizontal axis represents the incident angle (degrees (°)) at which light enters the multilayer film mirror, and the vertical axis represents the reflectance (%) for EUV rays having a wavelength (λ) of 13.5 nm. It can be seen from the figure that according to the multilayer film mirror of this embodiment, a high reflectivity of 45% or above (more preferably 50% or above) can be obtained in the entire wide incident angle range of 0°-20°.

Example 11

FIG. 18 is a schematic diagram of an exposure apparatus according to an embodiment of the present invention. As shown in the figure, EUV exposure 100 has an X-ray generating device (laser plasma X-ray source) 101 . This X-ray generator 101 has a spherical vacuum container 102, and the inside of the vacuum container 102 is evacuated by a vacuum pump. On the upper side inside the vacuum vessel 102 in the figure, a multilayer film parabolic mirror 104 is disposed, with its reflective surface 104a facing downward (+Z direction) in the figure.

A lens 106 is arranged on the right side of the vacuum vessel 102 in the figure, and a laser source not shown is arranged on the right side of the lens 106 . This laser source emits pulsed laser light 105 in the -Y direction. The pulsed laser light 105 converges on the focal point of the multilayer parabolic mirror through the lens 106 . A target material [xenon (Xe) or the like] is placed at the focal point, and when the target material 103 is irradiated with the condensed pulsed laser light 105, plasma 107 is generated. Plasma 107 emits soft X-rays (EUV rays) 108 in a wavelength range close to 13 nm.

An X-ray filter 109 that cuts visible light is provided at the lower portion of the vacuum container 102 . The EUV ray 108 is reflected in the +Z direction by the multilayer parabolic mirror 104 , and is introduced into the exposure chamber 110 through the X-ray filter 109 . At this point, the visible spectrum of EUV rays 108 is truncated.

Note that xenon gas is used as the target material in this embodiment, however, xenon clusters or xenon liquid droplets may also be used, and substances such as tin (Sn) may also be used. In addition, a laser plasma X-ray source is used as the X-ray generating device 101, however, a discharge plasma X-ray source may also be used. A discharge plasma X-ray source converts a target material into a plasma by a high pulse voltage discharge and causes X-rays to be emitted from the plasma.

In the figure, there is an exposure chamber 110 under the X-ray generator 101 . Inside the exposure chamber 110 is arranged an illumination optical system 113 . The illumination optical system 113 is composed of a condenser system reflector, a fly-eye optical system reflector, etc. (shown in a simplified shape in the figure), forms a circular EUV ray 108 incident from the X-ray generator 101, and to the left of the figure.

A mirror 115 is arranged on the left side of the illumination optical system 113 . The reflector 115 is a circular concave mirror, supported vertically (parallel to the Z axis) by a support member not shown in the figure, so that its reflective surface 115a faces to the right side of the figure (+Y direction). An optical path bending mirror 116 is arranged on the right-hand side of the reflecting mirror 115 in the figure. Above the optical path bending mirror 116 in the figure, a reflective mask 111 is arranged horizontally (parallel to the XY plane), so that the reflective surface 111a faces downward (+Z direction). The EUV rays emitted from the illumination optical system 113 are reflected and converged by the reflective mirror 115 , pass through the optical path bending mirror 116 , and reach the reflective surface 111 a of the reflective mask 111 .

The mirrors 115 and 116 are composed of a low thermal expansion glass substrate that is slightly thermally deformed and whose reflective surfaces are highly finely machined. Like the reflecting surface of the multilayer parabolic mirror, on the reflecting surface 115a of the reflecting mirror 115, high-refractive-index film layers and low-refractive-index film layers are alternately laminated to form a reflective multilayer film. Note that when using X-rays with a wavelength of 10-15 nm, substances such as molybdenum (Mo), ruthenium (Ru) and rhodium (Rh) in combination with substances such as silicon (Si), beryllium (Be) and carbon tetraboride ( B ₄ C) Combined reflective multilayer film.

Also, on the reflective surface 111a of the reflective mask 111, a reflective film layer composed of a multilayer film is formed. On the reflective film layer of the reflective mask 111 , a mask pattern is formed according to the pattern to be transferred onto the wafer 112 . The reflective mask 111 is attached to a mask holder 117 shown at the top of the figure. The mask holder 117 can move at least in the Y direction, and the EUV rays reflected by the optical path bending mirror 116 are sequentially scanned on the reflective mask 111 .

In the figure, a projection optical system 114 and a wafer (substrate coated with photosensitive resin) 112 are arranged in sequence from top to bottom under the reflective mask 111 . The projection optical system 114 is composed of a plurality of mirrors and the like. The wafer 112 is fixed on a wafer holder 118 movable in the XYZ directions so that its exposure surface 112a faces upward in the drawing (-Z direction). The EUV rays reflected by the reflective mask 111 are reduced by a predetermined reduction factor (such as 1/4) by the projection optical system, and an image is formed on the wafer 112 , and the pattern on the mask 111 is transmitted to the wafer 112 .

On the reflection mirror (excluding the skimming mirror using total reflection) used in the exposure apparatus 100 of this embodiment, a multilayer film having any one of the structures described in the above-mentioned first to tenth embodiments is formed . Note that the multilayer parabolic mirror 104, the reflection mirrors in the illumination optical system 113 and the projection optical system 114, etc. all have cooling mechanisms not shown in the figure to prevent the surface temperature from exceeding 100°C.

Since the incident ray of EUV rays striking the reflective surface of the multilayer parabolic mirror 104 varies considerably depending on its position on the plane, the length of the period in the plane also varies considerably. As mentioned above, the period length distribution of the multilayer parabolic mirror 104 and the substrate mounting position are slightly deviated, so the reflectivity changes due to the discrepancy between the expected incident angle and the actual incident angle when controlling the period length. According to the present embodiment, such a change in reflectance hardly occurs by using a multilayer film mirror having a wide half-width of the reflectance according to the above-described embodiments. In addition, by using a multilayer film having a wide reflectance range as the multilayer film mirrors constituting the illumination optical system 113 and the projection optical system 114, the image forming performance of the optical system can be kept high, and therefore, it is possible to make the image forming surface The amount of illumination on the lens and the amount of light in the pupil are consistent, and excellent resolution can be obtained.

In the present embodiment, the multilayered parabolic mirror 104 and the like are cooled, however, if the cooling is insufficient, it is also possible to use a film layer structure in which the reflectivity decreases little even if the temperature increases, as in the second to fourth embodiments. (Mo/SiC/Si, MoC/Si multilayer film, etc.), adding additional layers to the structure.

As described above, the present invention can be widely applied to the fields of multilayer film mirrors and exposure equipment.

Claims (26)

1. A multilayer mirror with reflective multilayer film, in the reflective multilayer film, the high refractive index film layer and the low refractive index film layer of EUV ray are stacked alternately, wherein: In the multilayer film (surface film layer group) on the light incident plane side, the low refractive index film layer is composed of a substance including molybdenum (Mo), and the high refractive index film layer is composed of a substance including silicon (Si); and In the multilayer film (deep film layer group) on the relative light incident plane side of the surface film layer group, the low refractive index film layer is made of a material comprising ruthenium (Ru), and the high refractive index film layer is made of a material comprising silicon ( Si) material composition. 2. The multilayer film reflector according to claim 1, wherein the logarithm of the high refractive index film layer and the low refractive index film layer in the surface film layer group is 2-10. 3. A method for manufacturing a multilayer film reflector, the multilayer film reflector has a reflective multilayer film, and in this reflective multilayer film, a high refractive index film layer and a low refractive index film layer to EUV rays are alternately laminated , the method includes the steps of: forming a deep film layer group by alternately depositing a substance comprising ruthenium and a substance comprising silicon on the substrate; and A surface film layer group is formed by alternately depositing a substance including molybdenum and a substance including silicon on the deep film layer group. 4. A multilayer reflective mirror with a reflective multilayer film, in the reflective multilayer film, a high refractive index film layer and a low refractive index film layer of EUV rays are alternately laminated, and the multilayer film reflector includes: Multilayer stack (surface stack) on the light incident plane side; an additional layer on the side of the surface film stack opposite the plane of incidence of light; and A multilayer film group (deep film layer group) on the side of the relative light incident plane of the additional layer, wherein: the reflectivity of the surface layer set is higher than the reflectivity of the deep layer set; and The reflected light rays are phase-shifted by the presence of said additional layer, such that the peak reflectivity of the entire mirror remains smaller and the reflectivity around the peak wavelength remains higher than in the absence of said additional layer . 5. A multilayer mirror with a reflective multilayer film, the high refractive index film layer and the low refractive index film layer of the EUV ray are alternately laminated in the reflective multilayer film, and the multilayer film mirror includes: Multilayer stack (surface stack) on the light incident plane side; an additional layer on the side of the surface film stack opposite the plane of incidence of light; and A multilayer film group (deep film layer group) on the side of the relative light incident plane of the additional layer, wherein: In the surface film layer group, the low refractive index film layer is composed of a substance including molybdenum (Mo), and the high refractive index film layer is composed of a substance including silicon (Si); In the deep film layer group, the low refractive index film layer is composed of a substance including molybdenum (Mo), and the high refractive index film layer is composed of a substance including silicon (Si); and The thickness of the additional layer is about half the period length of the multilayer film, or an integer multiple of the period length plus about half the period length. 6. A multilayer mirror with a reflective multilayer film, in the reflective multilayer film, the high refractive index film layer and the low refractive index film layer of the EUV ray are alternately laminated, and the multilayer film mirror includes: Multilayer stack (surface stack) on the light incident plane side; an additional layer on the side of the surface film stack opposite the plane of incidence of light; and A multilayer film group (deep film layer group) on the side of the relative light incident plane of the additional layer, wherein: In the surface film layer group, the low-refractive index film layer is composed of a substance including ruthenium (Ru), and the high-refractive index film layer is composed of a substance including silicon (Si); In the deep film layer group, the low refractive index film layer is composed of a substance including ruthenium (Ru), and the high refractive index film layer is composed of a substance including silicon (Si); and The thickness of the additional layer is about half the period length of the multilayer film, or an integer multiple of the period length plus about half the period length. 7. The multilayer film mirror according to any one of claims 4 to 6, wherein: The number of unit periodic structures (pairs) of the surface film layer group is 10-30; and The layer logarithm of the deep layer group is 5-50% of the layer logarithm of the surface layer group. 8. The multilayer film mirror according to any one of claims 4 to 7, wherein said additional layer is composed of one of silicon (Si), boron (B) and a substance comprising silicon and boron. 9. A multilayer mirror with a reflective multilayer film, the high refractive index film layer and the low refractive index film layer of the EUV ray are alternately stacked in the reflective multilayer film, and the multilayer film mirror includes: Multilayer stack (surface stack) on the light incident plane side; an additional layer on the side of the surface film stack opposite the plane of incidence of light; and A multilayer film group (deep film layer group) on the side of the relative light incident plane of the additional layer, wherein: In the multilayer film group (the first surface film layer group) on the incident plane side in the surface film group, the low-refractive index film layer is made of a substance including molybdenum (Mo), and the high-refractive index film layer is made of a material including silicon The material composition of (Si); In the multilayer film group (second surface film layer group) on the side of the additional layer in the surface film layer group, the low refractive index film layer is composed of a substance including ruthenium (Ru), and the high refractive index film layer is composed of Composition of matter including silicon (Si); and In the deep film layer group, the low refractive index film layer is composed of a substance including ruthenium (Ru), and the high refractive index film layer is composed of a substance including silicon (Si). 10. A multilayer mirror comprising a reflective multilayer film in which high refractive index film layers and low refractive index film layers alternate on a substrate under the condition that the Bragg reflection condition remains Lamination: Reflected rays from multiple interfaces of high and low index coatings are made in-phase for EUV rays, the multilayer mirror includes: Insertion layer with a thickness of half or more of the central wavelength of EUV rays, where The EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. 11. The multilayer reflective mirror according to claim 10, wherein a part of the layer pair of the high refractive index film layer and the low refractive index film layer is composed of two substances, and the other part is composed of three or more substances. 12. The multilayer film mirror according to claim 10 or 11, wherein: The reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 (film layers) are repeatedly stacked, the high refractive index film layer and the low refractive index film layer The refractive index film layers have different structures, and the low refractive index film layers L1 and L2 are formed of mutually different materials; The plurality of film layers includes L1/L2/L1/H film layer pairs repeatedly stacked film layer blocks and L1/H film layer pairs repeatedly stacked film layer blocks; and The number of stacking repetitions of film layer pairs in each film layer block is 1-50. 13. The multilayer film mirror according to claim 12, wherein the film layers included in each film layer pair have different thicknesses. 14. The multilayer film mirror according to any one of claims 10 to 13, wherein the thickness of each film layer is autonomously changed while being laminated so as to set the reflectivity for light having a wavelength of 13.1 nm to 13.9 nm 45% or more. 15. A multilayer mirror comprising a reflective multilayer film in which high refractive index film layers and low refractive index film layers alternate on a substrate under the condition that the Bragg reflection condition maintains Cascading: Reflected rays from multiple interfaces of high and low index coatings are made in-phase for EUV rays where: The reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 (film layers) are repeatedly stacked, the high refractive index film layer and the low refractive index film layer The refractive index film layers have different structures, and the low refractive index film layers L1 and L2 are formed of mutually different materials; The film layer block on the base side of the multilayer film mirror is formed by repeated lamination of L2/H film layer pairs; The second film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The third film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The fourth film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The fifth film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The sixth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The seventh film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The eighth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The number of film layer stacking repetitions in each film layer block is 1-50; and The EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. 16. The multilayer film mirror according to claim 15, wherein the reflectivity for glancing rays incident at an angle of incidence of at least 18 degrees to 25 degrees is 50% or more. 17. A multilayer mirror comprising a reflective multilayer film in which high refractive index film layers and low refractive index film layers alternate on a substrate under the condition that the Bragg reflection condition maintains Cascading: Reflected rays from multiple interfaces of high and low index coatings are made in-phase for EUV rays where: The reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 (film layers) are repeatedly stacked, the high refractive index film layer and the low refractive index film layer The refractive index film layers have different structures, and the low refractive index film layers L1 and L2 are formed of mutually different materials; The film layer block on the base side of the multilayer film mirror is formed by repeated lamination of L2/H film layer pairs; The second film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The third film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The fourth film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The fifth film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The sixth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The seventh film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The eighth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The number of film layer stacking repetitions in each film layer block is 1-50; and The EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. 18. The multilayer film reflector according to claim 17, wherein the entire reflective surface is set to have a uniform Reflectivity. 19. The multilayer film mirror according to claim 17 or 18, wherein by changing the total film thickness of the reflective multilayer film while maintaining the film thickness ratio of each layer in the reflective multilayer film will be for at least 0-20 The reflectance of glancing rays incident at an incident angle of 100 degrees is set to 50% or more. 20. A multilayer mirror comprising a reflective multilayer film in which high refractive index film layers and low refractive index film layers alternate on a substrate under the condition that the Bragg reflection condition maintains Cascading: Reflected rays from multiple interfaces of high and low index coatings are made in-phase for EUV rays where: The reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 (film layers) are repeatedly stacked, the high refractive index film layer and the low refractive index film layer The refractive index film layers have different structures, and the low refractive index film layers L1 and L2 are formed of mutually different materials; The film layer block on the base side of the multilayer film mirror is formed by repeated stacking of L1/L2/L1/H film layer pairs; The second film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The third film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The fourth film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The fifth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The sixth film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The seventh film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The eighth film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The ninth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The tenth film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The eleventh film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The twelfth film layer block starting from the base is formed by repeated lamination of L1/L2/L1/H film layer pairs; And the thirteenth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The number of film layer stacking repetitions in each film layer block is 1-50; and The EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. 21. The multilayer film mirror according to claim 20, wherein the reflectivity for glancing rays incident at an angle of incidence of at least 0-20 degrees is 45% or more. 22. A multilayer mirror comprising a reflective multilayer film in which layers of high refractive index and low refractive index layers alternate on a substrate under the condition that the Bragg reflection condition maintains Cascading: Reflected rays from multiple interfaces of high and low index coatings are made in-phase for EUV rays where: The reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 (film layers) are repeatedly stacked, the high refractive index film layer and the low refractive index film layer The refractive index film layers have different structures, and the low refractive index film layers L1 and L2 are formed of mutually different materials; The film layer block on the base side of the multilayer film mirror is formed by repeated lamination of L2/H film layer pairs; The second film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The third film layer block starting from the base is formed by repeated stacking of L2/H film layer pairs; The fourth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The fifth film layer block starting from the base is formed by repeated stacking of L2/H film layer pairs; The sixth film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The seventh film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The eighth film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The ninth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The tenth film layer block starting from the base is formed by repeated lamination of the L2/L1/H film layer pair; The eleventh film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The twelfth film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The thirteenth film layer block starting from the base is formed by repeated stacking of L1/L2/L1/H film layer pairs; The fourteenth film layer block starting from the base is formed by repeated stacking of L1/H film layer pairs; The number of film layer stacking repetitions in each film layer block is 1-50; and The EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. 23. The multilayer film reflector according to claim 22, wherein the reflectance for light having a wavelength of 13.1-13.9 nm is 45% or more. 24. A multilayer mirror comprising a reflective multilayer film in which layers of high and low index films alternate on a substrate under the condition that the Bragg reflection condition holds Cascading: Reflected rays from multiple interfaces of high and low index coatings are made in-phase for EUV rays where: The reflective multilayer film includes a plurality of film blocks, in which the high refractive index film layer H and the low refractive index film layers L1 and L2 (film layers) are repeatedly stacked, the high refractive index film layer and the low refractive index film layer The refractive index film layers have different structures, and the low refractive index film layers L1 and L2 are formed of mutually different materials; The film layer block on the base side of the multilayer film mirror is an H film layer; The second film layer block starting from the base is formed by repeated stacking of L2/H film layer pairs; The third film layer block starting from the base is formed by repeated stacking of L2/L1/H film layer pairs; The number of film layer stacking repetitions in each film layer block is 1-50; and The EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. 25. A multilayer mirror comprising a reflective multilayer film in which layers of high and low index films alternate on a substrate under the condition that the Bragg reflection condition remains Cascading: Reflected rays from multiple interfaces of high and low index coatings are made in-phase for EUV rays where: At least one of the high refractive index film layers has a thickness of half or more of the central wavelength of EUV rays; and The EUV ray wavelength range or incident angle range having a relatively high EUV ray reflectance is widened. 26. An exposure apparatus that forms a pattern by selectively irradiating a sensitive substrate with EUV rays, which includes the multilayer film mirror according to any one of claims 1 to 25 in an optical system.

Images