JP2009145700A - Catadioptric projection optical system, exposure apparatus and device manufacturing method - Google Patents

Abstract

【Task】
Provided is a highly accurate catadioptric projection optical system with a simple configuration.
[Solution]
A catadioptric projection optical system including at least two deflecting reflecting members, the first deflecting reflecting member including a first reflecting film, and a second deflecting reflecting member including a second reflecting film. The relationship between the angle φ1 of the predetermined light ray having the largest angle difference from the principal ray among the light rays incident on the first deflection reflection member and the angle φ2 of the predetermined light ray incident on the second deflection reflection member is With respect to the angle ψ1 of the principal ray incident on the first deflecting reflection member and the angle ψ2 of the principal ray incident on the second deflection reflecting member,
−1.1 ≦ (| φ1 | − | ψ1 |) / (| φ2 | − | ψ2 |) ≦ −0.8
The phase difference characteristic f (θ) between the S-polarized light and the P-polarized light of the reflecting film with respect to the angle difference θ between the predetermined light ray incident on each deflecting reflecting member and the chief ray is
| F (θ) + f (−θ) | <3 °
Meet.
[Selection] Figure 2

Description

  The present invention relates to a projection optical system that projects and exposes a reticle pattern onto a wafer, and more particularly to a catadioptric projection optical system using a mirror. The present invention also relates to an exposure apparatus using a catadioptric projection optical system and a device manufacturing method using the exposure apparatus.

  In a photolithography process for manufacturing a semiconductor integrated circuit, a projection exposure apparatus that projects and exposes a pattern on a reticle onto a wafer coated with a photoresist via a projection optical system is used.

    As the integration (miniaturization) of semiconductor elements (circuit patterns) progresses, the demands on the specifications and performance of projection optical systems have become increasingly severe. In general, in order to obtain a high resolving power, it is effective to shorten the exposure light wavelength and increase the NA of the projection optical system.

    When the wavelength of exposure light is shortened and reaches the wavelength region such as ArF excimer laser (wavelength: about 193 nm) and F2 laser (wavelength: about 157 nm), the usable glass material is made of quartz and fluorescent materials due to the decrease in transmittance. Limited to stone (calcium fluoride). In an optical system composed entirely of lenses (refractive elements), it is difficult to correct chromatic aberration because the difference between the dispersion values of quartz and fluorite is not large. In particular, when the exposure wavelength is 157 nm, the only usable glass material is fluorite, which makes it more difficult to correct chromatic aberration. In addition, as the NA increases, the diameter of the glass material increases, which is a major factor in increasing the cost of the apparatus.

    Therefore, in order to avoid the above-mentioned problems of chromatic aberration and large diameter of the glass material, a catadioptric projection optical system including a mirror (reflection element) in the optical system is used. However, when a catadioptric system is used, a member for deflecting the light beam is required to achieve imaging without causing pupil shielding. As a configuration thereof, a system for separating an incident light beam and an emitted light beam by using a total reflection deflection mirror in addition to a system having a beam splitter has been proposed.

    Such a system is disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-119244 (Patent Document 1), Japanese Patent Application Laid-Open No. 2006-138940 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2001-221950 (Patent Document 3). Yes. However, in the above prior art, the mirror is used for the purpose of achieving high reflectivity, and is usually covered with a composite dielectric layer or a reflective film composed of a combination of a metal and a dielectric layer. In general, when reflected by a dielectric layer, it can be influenced by polarization depending on the incident angle of light.

    In such a catadioptric system, a contrast difference depending on the circuit pattern direction on the reticle occurs. These contrast differences with respect to this direction can be observed as line width differences.

    Therefore, in order to reduce the contrast difference depending on the direction, there is a method for compensating for the difference between the polarized light perpendicular to the incident surface (S-polarized light) and the polarized light parallel to the incident surface (P-polarized light) by the characteristics of the reflective film of the mirror. Proposed.

    For example, in Japanese translations of PCT publication No. 2005-537676 (Patent Document 4), the light incident angle characteristics of the reflectance of S-polarized light and P-polarized light are reversed by two deflecting reflecting members, so that S-polarized light and P-polarized light are obtained. It compensates for the difference in intensity. Thereby, the direction-dependent contrast difference resulting from the intensity difference between polarization | polarized-light can be reduced.

In Japanese Patent Laid-Open No. 2006-220903 (Patent Document 5), the phase difference between S-polarized light and P-polarized light is corrected by configuring the deflecting and reflecting member with a metal film and a dielectric multilayer film. Thereby, the direction-dependent contrast difference resulting from the phase difference between polarization | polarized-lights can be reduced, and a desired optical image can be obtained.
JP 2006-119244 A JP 2006-138940 A JP 2001-221950 A JP 2005-537676 A JP 2006-220903 A

    However, JP 2005-537676 A (Patent Document 4) does not consider the phase difference between S-polarized light and P-polarized light. For this reason, a direction-dependent contrast difference resulting from this phase difference occurs, making it difficult to obtain a desired optical image.

    In Japanese Patent Laid-Open No. 2006-220903 (Patent Document 5), since the phase difference between S-polarized light and P-polarized light is corrected by a single mirror, the design difficulty of the reflective film is very high, and the phase difference is corrected. There is a limit to the degree of. In addition, a multilayer film having a number of layers of nine or more is used for the reflective film of Patent Document 5. When the number of layers of the multilayer film is large, it becomes necessary to reduce the tolerance of manufacturing error for each layer, and it becomes difficult to manufacture a deflecting reflecting member having desired optical characteristics.

  As described above, in any of the above conventional techniques, the phase difference between the S-polarized light and the P-polarized light cannot be reduced with a simple configuration.

  The present invention provides a projection optical system in which an optical system including at least two deflecting / reflecting members has a simple reflection film configuration and reduces the phase difference between S-polarized light and P-polarized light in transmitted light. In particular, the present invention provides a catadioptric projection optical system for realizing an optical image substantially free of a direction-dependent contrast difference for different directions of a pattern.

A catadioptric projection optical system according to one aspect of the present invention is a catadioptric projection optical system including at least two deflecting reflecting members, and includes a first deflecting reflecting member including a first reflecting film, A second deflecting / reflecting member provided with a reflecting film, and an angle φ1 of a predetermined ray having the largest angle difference with the principal ray among the rays incident on the first deflecting / reflecting member and the second The relationship between the angle φ2 of the predetermined ray incident on the deflecting reflection member is as follows: the angle ψ1 of the principal ray incident on the first deflection reflecting member and the angle of the principal ray incident on the second deflection reflecting member For ψ2,
−1.1 ≦ (| φ1 | − | ψ1 |) / (| φ2 | − | ψ2 |) ≦ −0.8
For the angle difference θ1 between the angle φ1 of the predetermined ray incident on the first deflecting reflection member and the angle ψ1 of the principal ray incident on the first deflecting reflection member. The phase difference characteristic f (θ1) between the S-polarized light and the P-polarized light in the first reflecting film of the deflecting reflecting member is
| F (θ1) + f (−θ1) | <3 °
For the angle difference θ2 between the angle φ2 of the predetermined ray incident on the second deflecting reflection member and the angle ψ2 of the principal ray incident on the second deflecting reflection member, The phase difference characteristic f (θ2) between the S-polarized light and the P-polarized light in the second reflecting film of the deflecting reflecting member is
| F (θ2) + f (−θ2) | <3 °
It is characterized by satisfying.

    Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, it is possible to provide a highly accurate catadioptric projection optical system in which the phase difference between S-polarized light and P-polarized light is reduced with a simple configuration.

    First, the overall configuration of a catadioptric projection optical system that is a premise of the present embodiment will be described with reference to the drawings.

    FIG. 1A shows a schematic diagram of a catadioptric projection optical system. A similar configuration is disclosed in, for example, Japanese Patent Laid-Open No. 2006-119244 (Patent Document 1).

    In FIG. 1A, 101 is a first object (original), 102 is a second object (substrate), and AX1 to AX3 are optical axes of the optical system. Also, as shown in FIG. 1B, the effective area that reaches the image of the first object 101 is an off-axis rectangular area that does not include the on-axis.

    The catadioptric projection optical system in FIG. 1A includes a first imaging optical system Gr1, a second imaging optical system Gr2, and a third imaging optical system in the order in which light rays from the first object 101 side pass. An imaging optical system Gr3 is included. The first imaging optical system Gr1 includes a lens group L1, and forms a real image (intermediate image IMG1) of the first object 101. The second imaging optical system Gr2 has a concave mirror M1 and a reciprocating optical system L2 arranged in the vicinity of the pupil position, and forms a real image (intermediate image IMG2) of the intermediate image IMG1. At that time, the light beam from the second imaging optical system Gr2 is deflected by the first deflecting / reflecting member FM1 (planar mirror) disposed at an inclination of 45 degrees with respect to the optical axis AX1, thereby providing the third It leads to the imaging optical system Gr3. Further, the second deflecting / reflecting member FM2 (planar mirror) disposed at an inclination of 45 degrees with respect to the optical axis AX2 deflects the light beam from the intermediate image IMG2, thereby causing the first object 101 and the second object to be deflected. The object 102 can be arranged in parallel. In FIG. 1A, the optical axis AX1 and the optical axis AX3 are configured to be parallel. The optical axis AX2 is orthogonal to the optical axis AX1 and the optical axis AX3.

    A schematic diagram of another catadioptric projection optical system is shown in FIG. The basic configuration is the same as that of FIG. 1A, but differs from the configuration of FIG. 1A in that the third imaging optical system Gr3 has a lens group L4. The third imaging optical system Gr3 includes a lens group L4 and a lens group L3, and forms a real image of the intermediate image IMG2 on the second object 102. A configuration similar to that of FIG. 6 is disclosed in Japanese Patent Laid-Open No. 2006-138940 (Patent Document 2).

    A schematic diagram of another catadioptric projection optical system is shown in FIG. A configuration similar to FIG. 5 is disclosed in Japanese Patent Laid-Open No. 2001-221950 (Patent Document 3).

    In FIG. 5, 101 is a first object, 102 is a second object, and AX1 and AX2 are optical axes of the optical system.

    The catadioptric projection optical system of FIG. 5 includes a first imaging optical system Gr1 and a second imaging optical system Gr in the order in which light rays from the first object 101 side pass. The first imaging optical system Gr1 includes a lens group L1a, a reciprocating optical system L1b, and a concave mirror M1 disposed in the vicinity of the pupil position, and forms a real image (intermediate image IMG1) of the first object 101. At that time, the light beam from the lens group L1a is deflected by the first deflecting / reflecting member FM1 disposed to be inclined with respect to the optical axis AX1, thereby leading to the lens group L1b which is a reciprocating optical system. The second deflecting / reflecting member FM2 disposed to be inclined with respect to the optical axis AX2 deflects the light beam from the reciprocating optical system L1b, thereby causing the first object 101 and the second object 102 to be parallel. It is possible to arrange in.

    Next, a catadioptric projection optical system embodiment as an embodiment of the present invention will be described in detail with reference to the drawings and conditional expressions.

    FIG. 2 is a schematic diagram showing the relationship between the deflecting / reflecting member (planar mirror) and the incident angle of the light beam in the catadioptric projection optical system of the present embodiment. The catadioptric projection optical system of the present embodiment includes a first deflecting / reflecting member FM1 having a first reflecting film 400 and a second deflecting / reflecting member FM2 having a second reflecting film 400 '. FIG. 2 shows incident angles of light rays (incident light rays) incident on the first deflection reflection member FM1 and the second deflection reflection member FM2 in a cross section including the optical axis AX1, the optical axis AX2, and the optical axis AX3. ing.

    Here, an angle formed between a predetermined light ray having the largest angle difference from the principal ray among the light rays incident on the first deflecting reflection member FM1 and the normal line of the reflecting surface (broken line in FIG. 2) is φ1, An angle formed between the predetermined light beam incident on the deflecting reflecting member FM2 and the normal line of the reflecting surface is φ2. In addition, the angle formed between the principal ray incident on the first deflecting / reflecting member FM1 and the normal line of the reflecting surface is ψ1, and the angle formed between the principal ray incident on the second deflecting / reflecting member FM2 and the normal line of the reflecting surface is set. Let ψ2.

    In the catadioptric projection optical system of the present embodiment, the ratio of the angle difference | φ1 | − | ψ1 | between the angle φ1 and the angle ψ1 and the angle difference | φ2 | − | ψ2 | between the angles φ2 and ψ2 (| φ1 | − It is desirable that | ψ1 |) / (| φ2 | − | ψ2 |) satisfy the following formula (1).

−1.1 ≦ (| φ1 | − | ψ1 |) / (| φ2 | − | ψ2 |) ≦ −0.8 (1)
Here, the difference between the angles of light rays (φ1, φ2) incident on each deflecting reflection member and the chief rays (ψ1, ψ2) is defined as an angle difference θ. At this time, the phase difference characteristic f (θ) between the S-polarized light and the P-polarized light in each of the first reflecting film and the second reflecting film covering the reflecting surface of each deflecting reflecting member satisfies the following formula (2). It is desirable.

| F (θ) + f (−θ) | <3 ° (2)
If the angle difference θ1 is set for the first deflecting / reflecting member FM1, the phase difference characteristic f (θ1) between the S-polarized light and the P-polarized light in the first deflecting / reflecting member FM1 is expressed by Expression (2 ′).

| F (θ1) + f (−θ1) | <3 ° (2 ′)
Similarly, regarding the second deflecting / reflecting member FM2, assuming that the angle difference is θ2, the phase difference characteristic f (θ2) between the S-polarized light and the P-polarized light in the second deflecting / reflecting member FM2 is expressed by Expression (2 ″). The

| F (θ2) + f (−θ2) | <3 ° (2 ″)
As described above, if the conditional expressions expressed by the formulas (1) and (2) are satisfied, each deflection deflection member can be obtained by combining the first deflection reflection member and the second deflection reflection member. The phase difference between the S-polarized light and the P-polarized light generated in the reflecting member can be compensated (reduced). Therefore, it is possible to realize a catadioptric projection optical system in which the phase difference between the S-polarized light and the P-polarized light in the transmitted light is reduced to such an extent that there is no substantial influence. Therefore, the direction-dependent contrast difference due to the polarization difference can be reduced, and a highly accurate optical image can be obtained.

    On the contrary, if the range of any one of the conditional expressions expressed by the mathematical expressions (1) and (2) is exceeded, it is difficult to reduce (compensate) the phase difference between the S-polarized light and the P-polarized light generated in each deflecting / reflecting member. become. For this reason, it becomes difficult to realize a projection optical system in which the phase difference between the S-polarized light and the P-polarized light in the transmitted light is not substantially adversely affected. As a result, a direction-dependent contrast difference caused by the phase difference (polarization difference) between the S-polarized light and the P-polarized light is generated, which makes it difficult to obtain a highly accurate optical image, which is not preferable.

    In addition, it is preferable that the angles φ1 and φ2 of the light beams incident on the first deflection reflection member FM1 and the second deflection reflection member FM2 satisfy the following formula (3).

85 ° ≦ | φ1 | + | φ2 | ≦ 95 ° (3)
More preferably, the angles [phi] 1 and [phi] 2 of the incident light rays are configured to satisfy the following formula (4).

88 ° ≦ | φ1 | + | φ2 | ≦ 92 ° (4)
If Expression (3) or Expression (4) is satisfied, the object plane and the image plane in the catadioptric projection optical system can be kept substantially parallel. Further, the phase difference between the S-polarized light and the P-polarized light can be prevented from being substantially adversely affected in all the light rays in the light beam. Therefore, the direction-dependent contrast difference due to the polarization difference can be reduced, and a highly accurate optical image can be obtained.

    Beyond the above range, it becomes difficult to avoid the adverse effects caused by the phase difference between the S-polarized light and the P-polarized light for all the light rays in the light beam. Then, a direction-dependent contrast difference caused by a phase difference (polarization difference) occurs, and it is difficult to obtain a highly accurate optical image, which is not preferable.

    Further, the angle φ1 of the light beam incident on the first deflecting / reflecting member FM1 and the angle φ2 of the light beam incident on the second deflecting / reflecting member FM2 are both in the range of 45 ° ± 5 ° (40 ° to 50 °). In this case, it is preferable that the phase difference characteristic f (θ) is zero. It is more preferable to configure the phase difference characteristic f (θ) to be 0 in a range of 45 ° ± 2 ° (43 ° to 47 °).

  With such a configuration, it is possible to remove the substantial influence due to the phase difference between the S-polarized light and the P-polarized light in all the light rays in the light beam. As a result, it is possible to reduce the direction-dependent contrast difference caused by the phase difference (polarization difference) and obtain a highly accurate optical image. Beyond this range, a certain amount of phase difference between S-polarized light and P-polarized light occurs in all the light rays in the light beam. For this reason, a direction-dependent contrast difference caused by the polarization difference is generated, and it is difficult to obtain a highly accurate optical image, which is not preferable.

  Moreover, it is preferable that the 1st reflective film which covers the reflective surface of 1st deflection | deviation reflective member FM1 and the 2nd reflective film which covers the reflective surface of 2nd deflection | deviation reflective member FM2 are the same structures.

  If the first reflection film and the second reflection film have the same configuration with respect to the type and thickness of the multilayer film, a plurality of reflection films can be easily formed. That is, it is possible to realize a catadioptric projection optical system in which the influence of the phase difference between the S-polarized light and the P-polarized light in the transmitted light is small by using a reflective film with low design difficulty. Therefore, the direction-dependent contrast difference caused by the phase difference (polarization difference) can be reduced, and a highly accurate optical image can be obtained.

    Each of the first reflective film that covers the reflective surface of the first deflective reflective member FM1 and the second reflective film that covers the reflective surface of the second deflective reflective member FM2 is a multilayer film having eight or fewer layers. It is preferable that It is more preferable if the number of layers of each reflective film is six or less.

    According to the above configuration, the catadioptric projection optical system of this embodiment can be realized with a reflective film having a relatively large error tolerance for each layer. That is, it is possible to realize a catadioptric projection optical system in which the influence of the phase difference between the S-polarized light and the P-polarized light in the transmitted light is small by using a reflective film with low manufacturing difficulty. Therefore, the direction-dependent contrast difference due to the polarization difference can be reduced, and a highly accurate optical image can be obtained.

  Further, as the NA of the optical system increases, the range of the angle of light incident on the first deflecting / reflecting member FM1 and the second deflecting / reflecting member FM2 becomes wider. This makes it difficult to control the phase difference between S-polarized light and P-polarized light when designing the first reflective film and the second reflective film. Therefore, the catadioptric projection optical system of the present embodiment is particularly effective when it has a very high NA of 0.8 or more. Further, the catadioptric projection optical system of the present embodiment is suitable for an exposure apparatus that uses short-wavelength light, preferably light having a wavelength of 200 nm or less as exposure light.

    FIG. 3A shows the relationship between the angle difference θ between the light ray incident on the deflecting reflection member and the principal ray and the pupil coordinates in the catadioptric projection optical system of the present embodiment. Here, the angle difference θ is an angle difference between the light ray incident on the deflecting reflection member and the principal ray in a cross section including the optical axis and the normal line of the reflection surface. In FIG. 3A, the angle difference θ is shown for each of the catadioptric projection optical system 100, the catadioptric projection optical system 200, and the catadioptric projection optical system 300. For each catadioptric projection optical system, the angle difference (| φ1 | − | ψ1 |) between the light beam incident on the first deflecting / reflecting member FM1 and the light beam incident on the second deflecting / reflecting member FM2 The angle difference (| φ2 | − | ψ2 |) of chief rays is shown. As shown in FIG. 3A, the angle difference θ in the present embodiment is substantially symmetrical about the principal ray.

    FIG. 3B shows the ratio (| φ1 | − | ψ1 |) / (| φ2 | − | ψ2 |) of the angle difference θ between the first deflecting / reflecting member FM1 and the second deflecting / reflecting member FM2 and pupil coordinates. It shows the relationship. As shown in FIG. 3B, the ratio of the angle difference of the catadioptric projection optical system in the present embodiment satisfies the conditional expression of Expression (1).

    Table 1 shows an example of the reflection film 400 that covers the reflection surface of each deflection reflection member with respect to the angle difference θ between the light ray incident on each deflection reflection member and the principal ray. The reflection film 400 can be employed for each of the first reflection film in the first deflection reflection member FM1 and the second reflection film in the second deflection reflection member FM2.

In Table 1, the surface number represents the order of the surfaces from the substrate surface (first surface) to the uppermost layer (sixth surface) of the reflecting surface. Further, the material is the name of each reflective film layer, d is the surface spacing, that is, the film thickness (nm) of each layer, λ is the wavelength of the light source (nm), and N is the refractive index of each material at the wavelength of the light source. Represents. As shown in Table 1, the reflective film 400 is a six-layer multilayer film in which Al, Al ₂ O ₃ , LaF ₃ , AlF ₃ , LaF ₃ , and MgF ₂ are sequentially stacked. The reflection film 400 can be used for each of the first reflection film in the first deflection reflection member FM1 and the second reflection film in the second deflection reflection member FM2.

    FIG. 4 shows the phase difference characteristics f (θ) and f (θ) + f (−θ) of S-polarized light and P-polarized light when the reflective film 400 is used. As shown in FIG. 4, according to the reflective film 400 of this example, the value of | f (θ) + f (−θ) | is within a range smaller than 3, and the phase difference characteristic f (θ) is The conditional expression according to Expression (2) is satisfied.

    FIG. 7 shows the S-polarized light when the reflective film 400 is applied to each of the reflective surfaces FM1 and FM2 for the catadioptric projection optical system 100, the catadioptric projection optical system 200, and the catadioptric projection optical system 300, respectively. And the phase difference between the P-polarized light. The phase difference between the S-polarized light and the P-polarized light is satisfactorily suppressed with respect to the light rays of all pupil coordinates, though the film structure is simpler than the prior art.

    As described above, according to the present embodiment, in an optical system including at least two deflecting and reflecting members, the projection optical in which the phase difference between the S-polarized light and the P-polarized light in the transmitted light is not substantially adversely affected with a simple reflecting film configuration. A system can be provided. In particular, it is possible to provide a catadioptric projection optical system that realizes an optical image substantially free of a contrast difference depending on the pattern direction.

  Hereinafter, an exposure apparatus 201 to which the catadioptric projection optical system 100 of the present invention is applied will be described with reference to FIG. FIG. 8 is a schematic sectional view showing the structure of an exposure apparatus 201 as one aspect of the present invention.

  The exposure apparatus 201 is a circuit formed on a reticle (mask) 220 via a liquid WT supplied to at least a part between the final lens surface on the wafer 240 side of the catadioptric projection optical system 100 and the wafer 240. This is an immersion exposure apparatus that exposes a pattern onto a wafer 240. A step-and-scan method is used as the exposure method.

  As shown in FIG. 8, the exposure apparatus 201 includes an illumination apparatus 210, a reticle stage 230 on which the reticle 220 is placed, a catadioptric projection optical system 100, a wafer stage 250 on which the wafer 240 is placed, a liquid supply / discharge A mechanism 260 and a control unit (not shown) are included. A control unit (not shown) is connected to control the illumination device 210, reticle stage 230, wafer stage 250, and liquid supply / discharge mechanism 260.

  The illumination device 210 illuminates the reticle 220 on which a transfer circuit pattern is formed, and includes a light source unit 212 and an illumination optical system 214.

For the light source unit 212, for example, an ArF excimer laser having a wavelength of about 193 nm, a KrF excimer laser having a wavelength of about 248 nm, or the like can be used as the light source. However, the type of the light source is not limited to the excimer laser. For example, an F ₂ laser having a wavelength of about 157 nm may be used, and the number of the light sources is not limited.

  The illumination optical system 214 is an optical system that illuminates the reticle 220.

  The reticle 220 is an original, on which a circuit pattern to be transferred is formed, and is supported and driven by a reticle stage 230. Diffracted light emitted from the reticle 220 is projected onto the wafer 240 via the catadioptric projection optical system 100. The reticle 220 and the wafer 240 are arranged in an optically conjugate relationship. Since the exposure apparatus 201 is a step-and-scan method, the pattern of the reticle 220 is transferred onto the wafer 240 by scanning the reticle 220 and the wafer 240 at a reduction ratio.

  The reticle stage 230 supports the reticle 220 via a reticle chuck (not shown) and is connected to a moving mechanism (not shown). A moving mechanism (not shown) is configured by a linear motor or the like, and can move the reticle 220 by driving the reticle stage 230 in the X-axis direction, the Y-axis direction, the Z-axis direction, and the rotation direction of each axis. The exposure apparatus 201 scans the reticle 220 and the wafer 240 in a synchronized state by a control unit (not shown). Here, in the plane of reticle 220 or wafer 240, the scanning direction is the Y axis, the direction perpendicular thereto is the X axis, and the direction perpendicular to the surface of reticle 220 or wafer 240 is the Z axis.

  The catadioptric projection optical system 100 is a catadioptric projection optical system that projects a pattern on the reticle 220 in a reduced scale onto an image plane. The catadioptric projection optical system 100 can be applied in any form as described above, and a detailed description thereof is omitted here.

  In this embodiment, the wafer 240 is used as the substrate, but a liquid crystal substrate or a glass plate can also be used. The wafer 240 is coated with a photoresist as a photosensitive material.

  The wafer stage 250 supports the wafer 240 by a wafer chuck (not shown). Similar to reticle stage 230, wafer stage 250 uses a linear motor to move wafer 240 in the X-axis direction, Y-axis direction, Z-axis direction, and the rotation direction of each axis.

  The liquid supply / discharge mechanism 260 supplies the liquid WT between the catadioptric projection optical system 100 and the wafer 240 via the supply / discharge nozzle 262. Specifically, the liquid WT is supplied between the wafer 240 and the final lens surface closest to the wafer 240 of the catadioptric projection optical system 100, and the supplied liquid WT is recovered. In other words, the gap formed between the catadioptric projection optical system 100 and the surface of the wafer 240 is filled with the liquid WT supplied from the liquid supply / discharge mechanism 260. The liquid WT is pure water in this embodiment. However, it is not particularly limited to pure water, and has a high transmission characteristic and a high refractive index characteristic with respect to the wavelength of exposure light, and is applied to the catadioptric projection optical system 100 and the photoresist applied to the wafer 240. Liquids with high chemical stability can be used.

  A control unit (not shown) has a CPU and a memory, and controls the operation of the exposure apparatus 201. The control unit is electrically connected to illumination device 210, reticle stage 230 (that is, a moving mechanism (not shown) of reticle stage 230), wafer stage 250 (that is, a moving mechanism (not shown) of the wafer stage), and liquid supply / discharge mechanism 260. ing. The control unit also has a function of controlling the supply and recovery of the liquid WT or the switching of the stop and the supply / discharge amount of the liquid WT based on conditions such as the driving direction of the wafer stage 250 at the time of exposure.

  In the exposure, the light beam emitted from the light source unit 212 illuminates the reticle 220 by the illumination optical system 214. Light that passes through the reticle 220 and reflects the reticle pattern is imaged on the wafer 240 by the catadioptric projection optical system 100 via the liquid WT. The catadioptric projection optical system 100 used by the exposure apparatus 201 has excellent imaging performance, and can provide a device (semiconductor device, liquid crystal device, etc.) with high throughput and good economic efficiency.

  Next, an embodiment of a device manufacturing method using the exposure apparatus 201 will be described with reference to FIGS. FIG. 9 is a flowchart for explaining how to fabricate devices (eg, semiconductor devices and liquid crystal devices). Here, an example of manufacturing a semiconductor device will be described. In step 1 (circuit design), a device circuit is designed. In step 2 (reticle fabrication), a reticle on which the designed circuit pattern is formed is fabricated. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the reticle and wafer. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer created in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). Including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 10 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition or the like. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 201 to expose a reticle circuit pattern onto the wafer. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. According to this device manufacturing method, it is possible to manufacture a higher quality device than before. Thus, the device manufacturing method using the exposure apparatus 201 and the resultant device also constitute one aspect of the present invention.

    The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the matters described in the above embodiments, and can be appropriately changed within the scope of the technical idea of the present invention.

(A) It is a schematic diagram of a catadioptric projection optical system. (B) It is a figure which shows the positional relationship of the exposure effective area | region on an object surface, and an optical axis about a catadioptric projection optical system. It is the schematic which shows the relationship between the deflection | reflecting reflection member and the incident angle of a light ray in the catadioptric projection optical system of a present Example. (A) It is the figure which showed the relationship between the angle difference (theta) of the light ray which injects into the deflecting reflection member of a present Example, and a chief ray, and a pupil coordinate. (B) It is the figure which showed the relationship between the ratio of angle difference (theta) in the 1st deflection | deviation reflection member FM1 and the 2nd deflection | deviation reflection member FM2 of a present Example, and a pupil coordinate. It is the figure which showed the phase difference characteristic f ((theta)) and f ((theta)) + f (-(theta)) of S polarization when using the reflective film of a present Example. It is a schematic diagram of another catadioptric projection optical system. It is a schematic diagram of another catadioptric projection optical system. It is the schematic which shows the phase difference of S polarized light and P polarized light of transmitted light about the catadioptric projection optical system of a present Example. It is a schematic sectional drawing which shows the structure of the exposure apparatus as one side surface of this invention. It is a flowchart for demonstrating the device manufacturing method in the Example of this invention. It is a flowchart for demonstrating the wafer process in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Catadioptric projection optical system 101 ... 1st object surface 102 ... 2nd object surface 200 ... Exposure apparatus Gr1 ... 1st imaging optical system Gr2 ... 2nd imaging optical system Gr3 ... 3rd imaging optical system IMG1 ... first intermediate image IMG2 ... second intermediate image FM1 ... first deflection reflection member FM2 ... second deflection reflection member AX1, AX2, AX3 ... optical axis ER ... exposure effective region

Claims (8)

A catadioptric projection optical system comprising at least two deflecting reflecting members,
A first deflecting and reflecting member provided with a first reflecting film;
A second deflecting reflecting member provided with a second reflecting film,
The relationship between the angle φ1 of the predetermined light ray having the largest angle difference from the principal ray among the light rays incident on the first deflection reflection member and the angle φ2 of the predetermined light ray incident on the second deflection reflection member is , With respect to an angle ψ1 of the chief ray incident on the first deflecting / reflecting member and an angle ψ2 of the chief ray incident on the second deflecting / reflecting member,
−1.1 ≦ (| φ1 | − | ψ1 |) / (| φ2 | − | ψ2 |) ≦ −0.8
The filling,
The first deflecting / reflecting member with respect to an angle difference θ1 between an angle φ1 of the predetermined ray incident on the first deflecting / reflecting member and an angle ψ1 of the principal ray incident on the first deflecting / reflecting member. The phase difference characteristic f (θ1) between S-polarized light and P-polarized light in the first reflective film of
| F (θ1) + f (−θ1) | <3 °
The filling,
The second deflecting / reflecting member with respect to an angle difference θ2 between an angle φ2 of the predetermined ray incident on the second deflecting / reflecting member and an angle ψ2 of the principal ray incident on the second deflecting / reflecting member The phase difference characteristic f (θ2) between S-polarized light and P-polarized light in the second reflective film of
| F (θ2) + f (−θ2) | <3 °
A catadioptric projection optical system characterized by satisfying An angle φ1 of the predetermined light beam incident on the first deflection reflection member and an angle φ2 of the predetermined light beam incident on the second deflection reflection member are:
85 ° ≦ | φ1 | + | φ2 | ≦ 95 °
The catadioptric projection optical system according to claim 1, wherein:     When the angle φ1 of the predetermined light incident on the first deflecting / reflecting member and the angle φ2 of the predetermined light incident on the second deflecting / reflecting member are both 45 ° ± 5 °, the phase difference characteristic 2. The catadioptric projection optical system according to claim 1, wherein f (θ1) and f (θ2) are zero.   2. The catadioptric projection optical system according to claim 1, wherein the first reflective film and the second reflective film have the same configuration.   2. The catadioptric projection optical system according to claim 1, wherein each of the first reflective film and the second reflective film is a multilayer film having eight or less layers. Each of the first reflection film and the second reflection film is a six-layer multilayer film in which Al, Al ₂ O ₃ , LaF ₃ , AlF ₃ , LaF ₃ , and MgF ₂ are sequentially stacked. The catadioptric projection optical system according to claim 5. An illumination optical system that illuminates the pattern of the original with light from the light source;
An exposure apparatus comprising: the catadioptric projection optical system according to claim 1, wherein the pattern of the original plate is projected onto a substrate. Exposing the substrate using the exposure apparatus according to claim 7;
And developing the exposed substrate. A device manufacturing method comprising: