WO2010044307A1 - Illumination optical system, aligner, and process for fabricating device - Google Patents

Abstract

An illumination distribution on a surface to be irradiated and a pupil intensity distribution at each point on the surface to be irradiated can be regulated, respectively, to desired distributions.  An illumination optical system, for illuminating the surfaces (M; W) to be irradiated based on the light from a light source (LS), comprises a spatial light modulator (3) having a plurality of optical elements arranged two-dimensionally and controlled individually, a focusing optical system (4) for forming based on the light passed through the spatial light modulator a predetermined light intensity distribution on a surface (5a) providing Fourier transform optically with respect to a surface where the plurality of optical elements are arranged, an optical integrator (5) having a plurality of unit wave front splitting surfaces arranged two-dimensionally on the surface providing Fourier transform, and a control section (CR) for regulating the pupil intensity distribution formed on the illumination pupil to a desired distribution based on the light from the spatial light modulator, and controlling the spatial light modulator in order to regulate the light intensity distribution formed on each of the plurality of unit wave front splitting surfaces, respectively, to a required distribution.

Description

Illumination optical system, exposure apparatus, and device manufacturing method

The present invention relates to an illumination optical system, an exposure apparatus, and a device manufacturing method. More specifically, the present invention relates to an illumination optical system suitable for an exposure apparatus for manufacturing devices such as a semiconductor element, an image sensor, a liquid crystal display element, and a thin film magnetic head in a lithography process.

In a typical exposure apparatus of this type, a secondary light source (generally an illumination pupil), which is a substantial surface light source composed of a number of light sources, passes through a fly-eye lens as an optical integrator. A predetermined light intensity distribution). Hereinafter, the light intensity distribution in the illumination pupil is referred to as “pupil intensity distribution”. The illumination pupil is a position where the illumination surface becomes the Fourier transform plane of the illumination pupil by the action of the optical system between the illumination pupil and the illumination surface (a mask or a wafer in the case of an exposure apparatus). Defined.

The light from the secondary light source is condensed by the condenser lens and then illuminates the mask on which a predetermined pattern is formed in a superimposed manner. The light transmitted through the mask forms an image on the wafer via the projection optical system, and the mask pattern is projected and exposed (transferred) onto the wafer. The pattern formed on the mask is highly integrated, and it is indispensable to obtain a uniform illuminance distribution on the wafer in order to accurately transfer this fine pattern onto the wafer.

In addition, for example, a technique for forming an annular or multipolar (bipolar, quadrupolar, etc.) pupil intensity distribution to improve the depth of focus and resolution of the projection optical system has been proposed (see Patent Document 1). ).

US Patent Publication No. 2006/0055834

In order to faithfully transfer the fine pattern of the mask onto the wafer, it is necessary not only to adjust the pupil intensity distribution to a desired shape but also to adjust the pupil intensity distribution for each point on the wafer almost uniformly. If there is a variation in the uniformity of the pupil intensity distribution at each point on the wafer, the line width of the pattern varies from position to position on the wafer, and the fine pattern of the mask has the desired line width over the entire exposure area. It cannot be transferred onto the wafer. Thus, in order to accurately transfer the fine pattern of the mask onto the wafer, the illuminance distribution on the wafer as the final irradiated surface and the pupil intensity distribution for each point on the wafer are adjusted to a desired distribution. is important.

The present invention has been made in view of the above-described problems, and provides an illumination optical system capable of adjusting the illuminance distribution on the irradiated surface and the pupil intensity distribution relating to each point on the irradiated surface to a desired distribution. With the goal. In addition, the present invention uses an illumination optical system capable of adjusting the illuminance distribution on the illuminated surface and the pupil intensity distribution for each point on the illuminated surface to a desired distribution, under appropriate illumination conditions. An object of the present invention is to provide an exposure apparatus capable of performing good exposure.

In order to solve the above problems, in the first embodiment of the present invention, in the illumination optical system that illuminates the illuminated surface based on the light from the light source
A spatial light modulator having a plurality of optical elements arranged two-dimensionally and individually controlled;
A condensing optical system that forms a predetermined light intensity distribution on an array surface of the plurality of optical elements of the spatial light modulator and a surface optically Fourier-transformed based on the light that has passed through the spatial light modulator; ,
An optical integrator having a plurality of unit wavefront division planes arranged two-dimensionally on the plane to be the Fourier transform;
The pupil intensity distribution formed on the illumination pupil based on the light from the spatial light modulator via the condensing optical system and the optical integrator is adjusted to a required distribution, and each of the plurality of unit wavefront division planes And a controller for controlling the spatial light modulator in order to adjust the light intensity distribution formed in each to a required distribution.

According to a second aspect of the present invention, there is provided an exposure apparatus comprising the illumination optical system according to the first aspect for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate.

In the third embodiment of the present invention, using the exposure apparatus of the second embodiment, an exposure step of exposing the predetermined pattern to the photosensitive substrate;
Developing the photosensitive substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

In the illumination optical system of the present invention, the control unit controls a plurality of optical elements of the spatial light modulator, and appropriately changes the light intensity distribution formed on each unit wavefront dividing surface of the optical integrator, thereby irradiating the irradiated surface. It is possible to adjust the illuminance distribution formed in (1) to a desired distribution (for example, uniform distribution) and to adjust the pupil intensity distribution for each point on the irradiated surface to a desired distribution (for example, uniform distribution).

That is, in the illumination optical system of the present invention, the illuminance distribution on the irradiated surface and the pupil intensity distribution regarding each point on the irradiated surface can be adjusted to a desired distribution. As a result, the exposure apparatus according to the present invention uses an illumination optical system capable of adjusting the illuminance distribution on the irradiated surface and the pupil intensity distribution for each point on the irradiated surface to a desired distribution, and has an appropriate illumination condition. Thus, good exposure can be performed, and as a result, a good device can be manufactured.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure explaining the effect | action of the spatial light modulator in a spatial light modulation unit. It is a fragmentary perspective view of the principal part of a spatial light modulator. It is a figure which shows typically the dipolar light intensity distribution formed in an illumination pupil. FIG. 5 is a diagram schematically showing a configuration of an incident surface of a micro fly's eye lens and a unit wavefront division surface on which light is incident in correspondence with the pupil intensity distribution of FIG. 4. It is a 1st figure explaining the effect | action of this embodiment. It is a figure which shows the pupil intensity distribution regarding each point P1, P2, P3 of FIG. It is a 2nd figure explaining the effect | action of this embodiment. It is a figure which shows the pupil intensity distribution regarding each point P1, P2, P3 of FIG. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of liquid crystal devices, such as a liquid crystal display element.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, the Z-axis is along the normal direction of the transfer surface (exposure surface) of the wafer W, which is a photosensitive substrate, and the Y-axis is in the direction parallel to the paper surface of FIG. In the W transfer surface, the X axis is set in a direction perpendicular to the paper surface of FIG.

Referring to FIG. 1, in the exposure apparatus of this embodiment, exposure light (illumination light) is supplied from a light source LS. As the light source LS, for example, an ArF excimer laser light source that supplies light with a wavelength of 193 nm, a KrF excimer laser light source that supplies light with a wavelength of 248 nm, or the like can be used. Light emitted from the light source LS is incident on the spatial light modulation unit SU via the beam transmitter 1. The beam transmitter 1 guides the incident light beam from the light source LS to the spatial light modulation unit SU while converting it into a light beam having an appropriate size and shape, and changes the position of the light beam incident on the spatial light modulation unit SU. And a function of actively correcting the angular variation.

The spatial light modulation unit SU spatially transmits light incident on the spatial light modulation unit SU via the spatial light modulator 3 having a plurality of mirror elements that are two-dimensionally arranged and individually controlled, and the beam transmitting unit 1. The light guide member 2 guides the light to the light modulator 3 and guides the light passing through the spatial light modulator 3 to the subsequent relay optical system 4. The specific configuration and operation of the spatial light modulation unit SU will be described later. The light emitted from the spatial light modulation unit SU enters the micro fly's eye lens (or fly eye lens) 5 via the relay optical system 4.

In the relay optical system 4, the front focal position substantially coincides with the position of the array surface of the plurality of mirror elements of the spatial light modulator 3, and the rear focal position and the position of the incident surface 5 a of the micro fly's eye lens 5 are the same. It is set to almost match. Therefore, as will be described later, the light that has passed through the spatial light modulator 3 forms a desired light intensity distribution on the incident surface 5a of the micro fly's eye lens 5 in accordance with the postures of the plurality of mirror elements. The micro fly's eye lens 5 is, for example, an optical element composed of a large number of micro lenses having positive refractive power arranged vertically and horizontally and densely. The micro fly's eye lens 5 is formed by etching a parallel plane plate to form a micro lens group. Has been.

In a micro fly's eye lens, unlike a fly eye lens composed of lens elements isolated from each other, a large number of micro lenses (micro refractive surfaces) are integrally formed without being isolated from each other. However, the micro fly's eye lens is the same wavefront division type optical integrator as the fly's eye lens in that the lens elements are arranged vertically and horizontally. A rectangular minute refracting surface as a unit wavefront dividing surface in the micro fly's eye lens 5 is a rectangular shape similar to the shape of the illumination field to be formed on the mask M (and the shape of the exposure region to be formed on the wafer W). It is. For example, a cylindrical micro fly's eye lens can be used as the micro fly's eye lens 5. The configuration and action of the cylindrical micro fly's eye lens are disclosed in, for example, US Pat. No. 6,913,373.

The light beam incident on the micro fly's eye lens 5 is two-dimensionally divided by a number of microlenses, and the illumination pupil formed by the incident light beam has almost the same light intensity distribution on the rear focal plane or in the vicinity of the illumination pupil. A secondary light source (i.e. pupil intensity distribution) is formed. A light beam from a secondary light source formed on the rear focal plane of the micro fly's eye lens 5 or in the vicinity thereof enters an aperture stop 6 disposed in the vicinity thereof.

The aperture stop 6 has an opening (light transmission part) having a shape corresponding to a secondary light source formed on the rear focal plane of the micro fly's eye lens 5 or in the vicinity thereof. The aperture stop 6 is configured to be detachable with respect to the illumination optical path, and is configured to be switchable between a plurality of aperture stops having openings having different sizes and shapes. As an aperture stop switching method, for example, a well-known turret method or slide method can be used. The aperture stop 6 is disposed at a position that is optically conjugate with an entrance pupil plane of the projection optical system PL described later, and defines a range that contributes to the illumination of the secondary light source. The installation of the aperture stop 6 can be omitted.

The light from the secondary light source limited by the aperture stop 6 illuminates the mask blind 8 in a superimposed manner via the condenser optical system 7. Thus, a rectangular illumination field corresponding to the shape and focal length of the rectangular micro-refractive surface of the micro fly's eye lens 5 is formed on the mask blind 8 as an illumination field stop. The light beam that has passed through the rectangular opening (light transmitting portion) of the mask blind 8 receives the light condensing action of the imaging optical system 9 and then illuminates the mask M on which a predetermined pattern is formed in a superimposed manner. That is, the imaging optical system 9 forms an image of the rectangular opening of the mask blind 8 on the mask M.

The light beam transmitted through the mask M held on the mask stage MS forms an image of a mask pattern on the wafer (photosensitive substrate) W held on the wafer stage WS through the projection optical system PL. In this way, batch exposure or scan exposure is performed while the wafer stage WS is two-dimensionally driven and controlled in a plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL, and thus the wafer W is two-dimensionally driven and controlled. As a result, the pattern of the mask M is sequentially exposed in each exposure region of the wafer W.

In this embodiment, the secondary light source formed by the micro fly's eye lens 5 is used as a light source, and the mask M arranged on the irradiated surface of the illumination optical system is Koehler illuminated. For this reason, the position where the secondary light source is formed is optically conjugate with the position of the aperture stop AS of the projection optical system PL, and the formation surface of the secondary light source can be called the illumination pupil plane of the illumination optical system. Typically, the irradiated surface (the surface on which the mask M is disposed or the surface on which the wafer W is disposed when the illumination optical system including the projection optical system PL is considered) is optical with respect to the illumination pupil plane. A Fourier transform plane. The pupil intensity distribution is a light intensity distribution (luminance distribution) on the illumination pupil plane of the illumination optical system or a plane optically conjugate with the illumination pupil plane.

When the number of wavefront divisions by the micro fly's eye lens 5 is relatively large, the overall light intensity distribution formed on the incident surface of the micro fly's eye lens 5 and the overall light intensity distribution (pupil intensity distribution) of the entire secondary light source. ) And a high correlation. For this reason, the light intensity distribution on the incident surface of the micro fly's eye lens 5 and the surface optically conjugate with the incident surface can also be referred to as a pupil intensity distribution. In the configuration of FIG. 1, the spatial light modulation unit SU, the relay optical system 4, and the micro fly's eye lens 5 constitute a distribution forming optical system that forms a pupil intensity distribution on the illumination pupil behind the micro fly's eye lens 5. is doing.

Referring to FIG. 2, the light guide member 2 in the spatial light modulation unit SU has, for example, a triangular prism prism mirror shape extending in the X direction. The light from the light source LS that has passed through the beam transmitter 1 is reflected by the first reflecting surface 2 a of the light guide member 2 and then enters the spatial light modulator 3. The light modulated by the spatial light modulator 3 is reflected by the second reflecting surface 2 b of the light guide member 2 and guided to the relay optical system 4.

As shown in FIGS. 2 and 3, the spatial light modulator 3 includes a main body 3a having a plurality of mirror elements SE arranged two-dimensionally, and a drive unit that individually controls and drives the postures of the plurality of mirror elements SE. 3b. For ease of explanation and illustration, FIGS. 2 and 3 show a configuration example in which the main body 3a of the spatial light modulator 3 includes 4 × 4 = 16 mirror elements SE. Much more mirror elements SE.

Referring to FIG. 2, among the light beams incident on the first reflecting surface 2 a of the light guide member 2 along the direction parallel to the optical axis AX, the light beam L1 is applied to the mirror element SEa of the plurality of mirror elements SE. The light beam L2 is incident on a mirror element SEb different from the mirror element SEa. Similarly, the light beam L3 is incident on a mirror element SEc different from the mirror elements SEa and SEb, and the light beam L4 is incident on a mirror element SEd different from the mirror elements SEa to SEc. The mirror elements SEa to SEd give spatial modulations set according to their positions to the lights L1 to L4.

In the spatial light modulator 3, a direction parallel to the optical axis AX in a reference state (hereinafter referred to as “reference state”) in which the reflection surfaces of all the mirror elements SE are set along one plane (XY plane). Are reflected by each mirror element SE of the spatial light modulator 3 and then reflected by the second reflecting surface 2b of the light guide member 2 in a direction substantially parallel to the optical axis AX. It is configured. The surface on which the plurality of mirror elements SE of the spatial light modulator 3 are arranged is positioned at or near the front focal position of the relay optical system 4.

Therefore, light reflected by the mirror elements SEa to SEd of the spatial light modulator 3 and given a predetermined angular distribution forms predetermined light intensity distributions SP1 to SP4 on the incident surface 5a of the micro fly's eye lens 5. That is, the relay optical system 4 determines the angle that the mirror elements SEa to SEd of the spatial light modulator 3 give to the emitted light on the incident surface 5a that is the far field region (Fraunhofer diffraction region) of the spatial light modulator 3. Convert to position.

Thus, the relay optical system 4 is based on the light that has passed through the spatial light modulator 3, and is a surface that is optically Fourier-transformed with the array surface of the plurality of mirror elements SE of the spatial light modulator 3, that is, a micro fly's eye lens. The condensing optical system which forms predetermined light intensity distribution in 5 entrance plane 5a is comprised. The light intensity distribution (pupil intensity distribution) of the secondary light source formed by the micro fly's eye lens 5 is a distribution corresponding to the light intensity distribution formed on the incident surface 5a by the spatial light modulator 3 and the relay optical system 4.

As shown in FIG. 3, the spatial light modulator 3 includes a large number of minute mirror elements SE arranged regularly and two-dimensionally along one plane with a planar reflecting surface as an upper surface. It is a movable multi-mirror. Each mirror element SE is movable, and the inclination of the reflection surface, that is, the inclination angle and the inclination direction of the reflection surface are independently controlled by the drive unit 3b that operates according to a command from the control unit CR. Each mirror element SE can be rotated continuously or discretely by a desired rotation angle with two directions parallel to the reflecting surface and two directions orthogonal to each other (for example, the X direction and the Y direction) as rotation axes. it can. That is, it is possible to two-dimensionally control the inclination of the reflection surface of each mirror element SE.

In addition, when the reflection surface of each mirror element SE is discretely rotated, the rotation angle is set in a plurality of states (for example,..., −2.5 degrees, −2.0 degrees,... 0 degrees, +0. It is better to perform switching control at 5 degrees... +2.5 degrees,. Although FIG. 3 shows a mirror element SE having a square outer shape, the outer shape of the mirror element SE is not limited to a square. However, from the viewpoint of light utilization efficiency, it is possible to provide a shape that can be arranged so as to reduce the gap between the mirror elements SE (a shape that can be closely packed). Further, from the viewpoint of light utilization efficiency, the interval between two adjacent mirror elements SE can be minimized.

In the present embodiment, as the spatial light modulator 3, for example, a spatial light modulator that continuously changes the directions of a plurality of mirror elements SE arranged two-dimensionally is used. As such a spatial light modulator, for example, Japanese Patent Laid-Open No. 10-503300 and corresponding European Patent Publication No. 779530, Japanese Patent Application Laid-Open No. 2004-78136, and corresponding US Pat. No. 6,900, The spatial light modulator disclosed in Japanese Patent No. 915, Japanese National Publication No. 2006-524349 and US Pat. No. 7,095,546 corresponding thereto, and Japanese Patent Application Laid-Open No. 2006-113437 can be used. Note that the directions of the plurality of mirror elements SE arranged two-dimensionally may be controlled so as to have a plurality of stages discretely.

Thus, in the spatial light modulator 3, the posture of the plurality of mirror elements SE is changed by the action of the drive unit 3b that operates according to the control signal from the control unit CR, and each mirror element SE is in a predetermined direction. Is set. The light reflected at a predetermined angle by each of the plurality of mirror elements SE of the spatial light modulator 3 forms a desired light intensity distribution on the incident surface 5 a of the micro fly's eye lens 5, and consequently, after the micro fly's eye lens 5. A pupil intensity distribution having a desired shape and size is formed on the illumination pupil at the side focal plane or in the vicinity thereof (position where the aperture stop 6 is disposed). Further, another illumination pupil position optically conjugate with the aperture stop 6, that is, the pupil position of the imaging optical system 9 and the pupil position of the projection optical system PL (position where the aperture stop AS is disposed) are also desired. A pupil intensity distribution is formed.

In the exposure apparatus, in order to transfer the pattern of the mask M onto the wafer W with high accuracy and faithfully, it is important to perform exposure under appropriate illumination conditions according to the pattern characteristics. In the present embodiment, as a means for variably forming a light intensity distribution in the illumination pupil, a spatial light modulator 3 in which the postures of the plurality of mirror elements SE are individually changed is provided. Accordingly, the action of the spatial light modulator 3 can freely and quickly change the pupil intensity distribution (and thus the illumination condition) formed on the illumination pupil.

However, if the illuminance distribution on the wafer W, which is the final irradiated surface, and the pupil intensity distribution for each point on the wafer W are not adjusted to a desired distribution (for example, a uniform distribution), a fine pattern of the mask M is formed. It cannot be accurately transferred onto the wafer W. Therefore, in the present embodiment, the illuminance distribution measuring unit 10 that measures the illuminance distribution on the image plane of the projection optical system PL, and the pupil intensity distribution on the pupil plane of the projection optical system PL based on the light that has passed through the projection optical system PL. A pupil intensity distribution measurement unit 11 that measures the intensity of light and a control unit that controls the postures of the plurality of optical elements SE of the spatial light modulator 3 based on the measurement result of the illuminance distribution measurement unit 10 and the measurement result of the pupil intensity distribution measurement unit 11 With CR.

The illuminance distribution measurement unit 10 monitors the illuminance distribution on the image plane of the projection optical system PL according to a known configuration. The pupil intensity distribution measuring unit 11 includes a CCD imaging unit having an imaging surface disposed at a position optically conjugate with the pupil position of the projection optical system PL, for example, and an image plane (that is, an irradiated surface) of the projection optical system PL. The pupil intensity distribution (pupil intensity distribution formed on the pupil plane of the projection optical system PL by the light incident on each point) is monitored for each point above. For the detailed configuration and operation of the pupil intensity distribution measuring unit 11, reference can be made to, for example, US Patent Publication No. 2008/0030707.

In the following description, in order to facilitate understanding of the operational effects of the present embodiment, two elliptical shapes as shown in FIG. 4 are provided on the rear focal plane of the micro fly's eye lens 5 or in the vicinity of the illumination pupil. It is assumed that a dipole pupil intensity distribution (secondary light source) 20 composed of substantial surface light sources (hereinafter simply referred to as “surface light sources”) 20a and 20b is formed. In the following description, the term “illumination pupil” simply refers to the rear focal plane of the micro fly's eye lens 5 or the illumination pupil in the vicinity thereof.

Referring to FIG. 4, the dipole pupil intensity distribution 20 formed on the illumination pupil has a pair of surface light sources 20a and 20b spaced in the Z direction across the optical axis AX. As shown in FIG. 5, the light forming the dipole pupil intensity distribution 20 is hatched in the figure among a number of rectangular microlenses 5b arranged densely in the vertical and horizontal directions of the micro fly's eye lens 5. The light enters the applied plurality of microlenses 5ba. However, in FIG. 5, for the sake of clarity, the number of rectangular microlenses 5b constituting the micro fly's eye lens 5 is expressed considerably smaller than actual.

As described above, the micro fly's eye lens 5 includes a plurality of unit wavefront division planes (each of which is two-dimensionally arranged on a plane that is optically Fourier transformed with the arrangement plane of the plurality of mirror elements SE of the spatial light modulator 3. An optical integrator having an incident surface of the minute lens 5b is configured. The two-dimensionally arranged unit wavefront dividing surfaces of the micro fly's eye lens 5 are optically conjugate with the mask M (and thus the wafer W) that is the surface to be irradiated.

In addition, within the range in which the effect of the present embodiment is achieved, the plurality of unit wavefront division surfaces of the micro fly's eye lens 5 that are two-dimensionally arranged are optically connected to the arrangement surface of the plurality of mirror elements SE of the spatial light modulator 3. Alternatively, it may be arranged at a position defocused from the surface to be Fourier transformed. In addition, within a range where the effects of the present embodiment are achieved, the plurality of unit wavefront division surfaces of the micro fly's eye lens 5 that are two-dimensionally arranged are optically conjugate with the mask M (wafer W) that is the irradiated surface. You may arrange | position in the position defocused from the surface.

FIG. 6 is a diagram for explaining the operation of the present embodiment. In FIG. 6, in order to facilitate understanding of the explanation, among the many microlenses 5 b constituting the micro fly's eye lens 5, four microlenses into which light enters corresponding to the dipole pupil intensity distribution 20. 5ba and one microlens 5bb on which no light is incident are shown. In addition, the intensity distribution along the YZ plane of the light incident on the four microlenses 5ba is represented by a hatched area. Here, the intensity of incident light increases as the height of the hatching region in the Y direction increases.

In the present embodiment, the spatial light modulator 3 has much more mirror elements SE than the number of microlenses 5b constituting the micro fly's eye lens 5, and the postures thereof can be individually changed. Therefore, the light intensity distribution formed on the incident surface 5a of the micro fly's eye lens 5 is freely changed by the action of the spatial light modulator 3, and as a result, the incident surface (that is, each of the minute lenses 5b of the micro fly's eye lens 5). It is possible to freely change the intensity distribution of light incident on the unit wavefront dividing plane.

In the example shown in FIG. 6, the intensity distribution of light incident on the two microlenses 5ba in the + Z direction is the same, and the intensity distribution of light incident on the two microlenses 5ba in the −Z direction is the same. is there. The intensity distribution of light incident on the two microlenses 5ba on the + Z direction side and the intensity distribution of light incident on the two microlenses 5ba on the −Z direction side are symmetric with respect to the optical axis AX.

Specifically, in the intensity distribution of light incident on the two microlenses 5ba on the + Z direction side, the intensity is the largest at the end on the + Z direction side, the intensity is the smallest at the center position along the Z direction, and the intensity distribution on the + Z direction side is The intensity monotonously decreases from the end toward the center position, and the intensity monotonously increases from the center position toward the end on the −Z direction side. In this case, the intensity distribution of the light incident on the four microlenses 5ba is superimposed on the position of the mask blind 8 optically conjugate with the mask M (and thus the wafer W), which is the irradiated surface, so that the illumination intensity distribution is almost uniform. Is formed.

The light reaching the center point in the exposure area on the wafer W (the stationary exposure area in the case of scanning exposure), that is, the light reaching the center point P1 of the opening of the mask blind 8, as shown by the broken line in FIG. It is the light with the smallest intensity that passes through the center position of the four microlenses 5ba. Therefore, as shown in the center diagram of FIG. 7, in the dipole light intensity distribution formed in the illumination pupil by the light reaching the center point P1, that is, the pupil intensity distribution 21 related to the center point P1, the surface light source on the + Z direction side The light intensity of 21a is equal to the light intensity of the surface light source 21b on the -Z direction side, and the light intensity is relatively small.

Of the light reaching the one peripheral point along the Y direction from the center point in the exposure area on the wafer W, that is, the light reaching the peripheral point P2 on the + Z direction side of the opening of the mask blind 8, 2 on the + Z direction side The light from the two microlenses 5ba is light having a relatively high intensity passing through the end on the −Z direction side as indicated by the thin solid line in FIG. 6, and the light from the two microlenses 5ba on the −Z direction side is illustrated in FIG. As shown by the thick solid line in FIG. 6, the light has the highest intensity that passes through the end on the −Z direction side. Therefore, as shown in the left diagram of FIG. 7, in the dipole light intensity distribution formed on the illumination pupil by the light reaching the peripheral point P2, that is, in the pupil intensity distribution 22 related to the peripheral point P2, the surface light source on the + Z direction side The light intensity of 22a is relatively high, and the light intensity of the surface light source 22b on the −Z direction side is the highest.

Of the light that reaches the other peripheral point along the Y direction from the center point in the exposure area on the wafer W, that is, the light that reaches the peripheral point P3 on the −Z direction side of the opening of the mask blind 8, it is on the + Z direction side. The light from the two microlenses 5ba is the light having the highest intensity passing through the end on the + Z direction side as shown by the thick solid line in FIG. 6, and the light from the two microlenses 5ba on the −Z direction side is shown in FIG. As indicated by the thin solid line, the light has a relatively high intensity that passes through the end on the + Z direction side. Therefore, as shown in the diagram on the right side of FIG. 7, in the dipole light intensity distribution formed on the illumination pupil by the light reaching the peripheral point P3, that is, the pupil intensity distribution 23 related to the peripheral point P3, the surface light source on the + Z direction side The light intensity of 23a is the highest, and the light intensity of the surface light source 23b on the -Z direction side is relatively high.

As described above, in the example shown in FIGS. 6 and 7, the pupil intensity distribution related to the predetermined point P2 on the irradiated surface 8 is set as the first pupil intensity distribution, and the predetermined 1 on the irradiated surface 8 is used. Two or more types of light intensity distributions are formed on each of the plurality of unit wavefront division planes so that the pupil intensity distribution relating to another point (P1 or P3) different from the point P2 is the second pupil intensity distribution. The light intensity distribution.

In the example shown in FIG. 6 and FIG. 7 described above, in other words, a first setting step for setting a first target pupil intensity distribution that is a target of the pupil intensity distribution for a predetermined point P2 on the irradiated surface, A second setting step of setting a second target pupil intensity distribution that is a target of the pupil intensity distribution related to another point (P1 or P3) different from the predetermined one point P2 on the irradiation surface. Here, the pupil intensity distribution related to the predetermined one point P2 is set as the first target pupil intensity distribution, and the pupil intensity distribution related to another one point (P1 or P3) is set as the second target pupil intensity distribution. The pupil intensity distribution to be formed is adjusted, and the light intensity distribution formed on each of the plurality of unit wavefront division planes is adjusted.

At this time, a first division step of dividing the first target pupil intensity distribution according to the plurality of unit wavefront division planes, and light intensity at a position corresponding to the predetermined one point in the divided first target pupil intensity distribution A first light intensity calculation step for calculating the second target pupil intensity distribution, a second division step for dividing the second target pupil intensity distribution according to the plurality of unit wavefront division planes, and the different second target pupil intensity distribution in the divided second target pupil intensity distribution. A second light intensity calculation step for calculating the light intensity at a position corresponding to one point, a predetermined point P2 calculated in the first and second light intensity calculation steps, and another point (P1 or P3) And calculating a light intensity distribution to be formed on the plurality of unit wavefront division planes based on the light intensity at the position corresponding to.

Next, in the example shown in FIG. 8, light having the same distribution as the intensity distribution of the light incident on the two microlenses 5ba on the + Z direction side in FIG. 6 is incident on the microlens 5ba on the −Z direction side. 6, light having the same distribution as the intensity distribution of the light incident on the two minute lenses 5ba on the −Z direction side is incident on the minute lens 5ba on the + Z direction side. In the example shown in FIG. 8 as well, as in the example shown in FIG. 6, the mask blind 8 that is optically conjugate with the mask M (and thus the wafer W), which is the irradiated surface, is incident on the four microlenses 5ba. The light intensity distribution is superimposed to form a substantially uniform illuminance distribution.

Then, the light reaching the center point P1 of the opening of the mask blind 8 is the light having the smallest intensity that passes through the center position of the four microlenses 5ba, as indicated by the broken line in FIG. Therefore, as shown in the center diagram of FIG. 9, in the pupil intensity distribution 21 with respect to the center point P1, the light intensity of the surface light source 21a on the + Z direction side and the light intensity of the surface light source 21b on the −Z direction side are equal to each other. Its light intensity is relatively small.

Of the light reaching the peripheral point P2 of the opening of the mask blind 8, the light from the two microlenses 5ba on the + Z direction side has the highest intensity passing through the end on the −Z direction side as shown by the thick solid line in FIG. The light from the two microlenses 5ba on the −Z direction side is light having a relatively high intensity that passes through the end on the −Z direction side as shown by the thin solid line in FIG. Therefore, as shown in the left diagram of FIG. 9, in the pupil intensity distribution 22 related to the peripheral point P2, the light intensity of the surface light source 22a on the + Z direction side is the highest, and the light intensity of the surface light source 22b on the −Z direction side is compared. Big.

Of the light reaching the peripheral point P3 of the opening of the mask blind 8, the light from the two minute lenses 5ba on the + Z direction side has a relatively high intensity passing through the end on the + Z direction side as shown by the thin solid line in FIG. The light from the two minute lenses 5ba on the −Z direction side is the light having the highest intensity passing through the end on the + Z direction side as shown by the thick solid line in FIG. Therefore, as shown in the diagram on the right side of FIG. 9, in the pupil intensity distribution 23 related to the peripheral point P3, the light intensity of the surface light source 23a on the + Z direction side is relatively large, and the light intensity of the surface light source 23b on the −Z direction side is The biggest.

For example, referring to FIG. 6, in the optical ideal state, when the intensity distribution of light incident on the four microlenses 5ba is uniform and equal to each other, a uniform illuminance distribution is formed at the position of the mask blind 8. As a result, it is understood that a uniform illuminance distribution is formed even on the wafer W which is the final irradiated surface. Further, in the pupil intensity distributions 21, 22, and 23 regarding the points P1, P2, and P3 of the opening of the mask blind 8, the light intensities of the surface light sources 21a, 21b, 22a, 22b, 23a, and 23b may be equal to each other. Understood. That is, the pupil intensity distribution for each point in the opening of the mask blind 8 is uniform, and consequently the pupil intensity distribution for each point in the exposure area on the wafer W is also uniform.

However, in an actual optical system, even if the intensity distribution of light incident on the required minute lens 5ba is set to be uniform and equal to each other, the uniform illuminance distribution and the mask blind 8 at the position of the mask blind 8 for various reasons. It is not always possible to obtain a uniform pupil intensity distribution for each point in the aperture. Further, even if a uniform illuminance distribution and a uniform pupil intensity distribution can be obtained for each point at the position of the mask blind 8, the uniform illuminance distribution on the wafer W and each point in the exposure area on the wafer W can be obtained. A uniform pupil intensity distribution cannot always be obtained.

This means that in an actual optical system, in order to obtain a uniform illuminance distribution on the wafer W, for example, it is required to adjust the illuminance distribution at the position of the mask blind 8 to a required non-uniform distribution. ing. In order to obtain a uniform pupil intensity distribution for each point in the exposure area on the wafer W, for example, it is required to adjust the pupil intensity distribution for each point in the opening of the mask blind 8 to a required non-uniform distribution. Is meant to be.

Referring to FIGS. 6 to 9, in this embodiment, the spatial light modulator 3 is used to appropriately change the intensity distribution of light incident on the incident surface of each microlens 5b of the micro fly's eye lens 5 to thereby change the mask. It is understood that it is possible to independently adjust the pupil intensity distribution regarding the points P1, P2, and P3 in the opening of the mask blind 8 while maintaining the illuminance distribution formed at the position of the blind 8 substantially uniform. . Further, by appropriately changing the intensity distribution of light incident on the incident surface (each unit wavefront dividing surface) of each micro lens 5b, the illuminance distribution formed at the position of the mask blind 8 is adjusted to a desired distribution, It is easily estimated that the pupil intensity distribution for each point in the opening of the mask blind 8 can be adjusted to a desired distribution.

In other words, in the present embodiment, the controller CR individually controls the postures of the plurality of mirror elements SE of the spatial light modulator 3 to form the light formed on each of the plurality of unit wavefront dividing surfaces of the micro fly's eye lens 5. By appropriately changing the intensity distribution, the illuminance distribution formed in the exposure area on the wafer W (or the illumination area on the mask M) at a position optically conjugate with the position of the mask blind 8 is adjusted to a desired distribution. However, the pupil intensity distribution for each point in the exposure area on the wafer W (or the illumination area on the mask M) can be adjusted to a desired distribution. Thus, the control unit CR adjusts the pupil intensity distribution formed in the illumination pupil based on the light from the spatial light modulator 3 via the relay optical system 4 and the micro fly's eye lens 5 to a required distribution. The light intensity distribution formed on each of the plurality of unit wavefront division surfaces of the micro fly's eye lens 5 has a function of controlling the spatial light modulator 3 to adjust the light intensity distribution to a required distribution.

Specifically, in the present embodiment, the control unit CR controls the postures of the plurality of mirror elements SE of the spatial light modulator 3 based on the measurement result of the illuminance distribution measurement unit 10 and the measurement result of the pupil intensity distribution measurement unit 11. Thus, the illuminance distribution formed in the exposure area on the wafer W at the image plane position of the projection optical system PL is adjusted to a desired distribution (for example, uniform distribution), and each point in the exposure area on the wafer W is adjusted. The pupil intensity distribution formed by the light incident on the pupil position of the projection optical system PL can be adjusted to a desired distribution (for example, a uniform distribution).

As described above, in the illumination optical system (1 to 11) of the present embodiment, the illuminance distribution on the wafer W that is the final irradiated surface and the pupil intensity distribution regarding each point in the exposure area on the wafer W are desired. The distribution can be adjusted. Therefore, in the exposure apparatus (1 to 11, MS, PL, WS) of this embodiment, the illuminance distribution on the wafer W and the pupil intensity distribution for each point in the exposure area on the wafer W are adjusted to a desired distribution. By using the illumination optical system (1 to 11) capable of performing good exposure, it is possible to perform good exposure under appropriate illumination conditions according to the fine pattern of the mask M. As a result, the fine pattern of the mask M is applied to the entire exposure region. Then, it can be accurately transferred onto the wafer W with a desired line width.

In the above-described embodiment, the relay optical system 4 serving as a condensing optical system that functions as a Fourier transform lens is disposed in the optical path between the spatial light modulation unit SU and the micro fly's eye lens 5. However, the present invention is not limited to this, and an optical system including an afocal optical system, a conical axicon system, a variable magnification optical system, or the like can be arranged instead of the relay optical system 4. This type of optical system is disclosed in International Publication No. 2005 / 076045A1 and corresponding US Patent Application Publication No. 2006 / 0170901A.

In the above description, the function and effect of the present invention are described by taking, as an example, modified illumination in which a dipole pupil intensity distribution is formed on the illumination pupil, that is, dipole illumination. However, the present invention is not limited to dipole illumination. For example, zonal illumination in which an annular pupil intensity distribution is formed, multipolar illumination in which a multipolar pupil intensity distribution other than dipole illumination is formed, and the like. In contrast, it is apparent that the same effects can be obtained by applying the present invention.

In the above description, the function and effect of the present invention are described by taking the micro fly's eye lens 5 in which lens elements are two-dimensionally arranged vertically and horizontally as an example of a wavefront division type optical integrator. However, it is clear that the same effect can be obtained by applying the present invention to the cylindrical micro fly's eye lens disclosed in, for example, US Pat. No. 6,913,373.

When a cylindrical micro fly's eye lens is applied, a plurality of cylindrical refracting surfaces (first cylindrical lens group) in which the cylindrical micro fly's eye lens is arranged side by side in a first direction across the optical axis. And a plurality of cylindrical refracting surfaces (second cylindrical lens groups) arranged side by side in a second direction orthogonal to the first direction across the optical axis. A unit wavefront division plane is defined by the second cylindrical lens group.

In the above-described embodiment, the micro fly's eye lens 5 is used as the optical integrator, but instead, an internal reflection type optical integrator (typically a rod type integrator) may be used. In this case, the condensing lens is arranged on the rear side of the relay optical system 4 so that the front focal position thereof coincides with the rear focal position of the relay optical system 4, and at or near the rear focal position of the condensing lens. The rod-type integrator is arranged so that the incident end is positioned. At this time, the injection end of the rod type integrator is positioned at the mask blind 8. When using a rod-type integrator, a position optically conjugate with the position of the aperture stop AS of the projection optical system PL in the imaging optical system 9 downstream of the rod-type integrator can be called an illumination pupil plane. In addition, since a virtual image of the secondary light source of the illumination pupil plane is formed at the position of the entrance surface of the rod integrator, this position and a position optically conjugate with this position are also called the illumination pupil plane. Can do.

Here, a plane perpendicular to the optical axis passing through a position where the rear focal position of the relay optical system 4 coincides with the front focal position of the condenser lens is divided into a plurality of unit wavefronts when the micro fly's eye lens 5 is used. The surface corresponds to a surface arranged two-dimensionally. Therefore, even when a rod type integrator is used, the same effect as that of the above-described embodiment can be obtained by controlling the light intensity distribution in the plane passing through the rear focal position of the relay optical system 4 according to the above-described embodiment. Can do.

In the above description, as the spatial light modulator having a plurality of optical elements that are two-dimensionally arranged and individually controlled, the direction (angle: inclination) of the plurality of two-dimensionally arranged reflecting surfaces is set. An individually controllable spatial light modulator is used. However, the present invention is not limited to this. For example, a spatial light modulator that can individually control the height (position) of a plurality of two-dimensionally arranged reflecting surfaces can be used. As such a spatial light modulator, for example, Japanese Patent Laid-Open No. 6-281869 and US Pat. No. 5,312,513 corresponding thereto, and Japanese Patent Laid-Open No. 2004-520618 and US Pat. The spatial light modulator disclosed in FIG. 1d of Japanese Patent No. 6,885,493 can be used. In these spatial light modulators, by forming a two-dimensional height distribution, an action similar to that of the diffractive surface can be given to incident light. Note that the spatial light modulator having a plurality of two-dimensionally arranged reflection surfaces described above is disclosed in, for example, Japanese Patent Publication No. 2006-513442 and US Pat. No. 6,891,655 corresponding thereto, Modifications may be made in accordance with the disclosure of Japanese Patent Publication No. 2005-524112 and US Patent Publication No. 2005/0095749 corresponding thereto.

In the above description, a reflective spatial light modulator having a plurality of mirror elements is used. However, the present invention is not limited to this. For example, transmission disclosed in US Pat. No. 5,229,872 A type of spatial light modulator may be used.

In the above-described embodiment, a variable pattern forming apparatus that forms a predetermined pattern based on predetermined electronic data can be used instead of a mask. By using such a variable pattern forming apparatus, the influence on the synchronization accuracy can be minimized even if the pattern surface is placed vertically. As the variable pattern forming apparatus, for example, a DMD (digital micromirror device) including a plurality of reflecting elements driven based on predetermined electronic data can be used. An exposure apparatus using DMD is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-304135, pamphlet of International Patent Publication No. 2006/080285 and US Patent Publication No. 2007/0296936 corresponding thereto. In addition to a non-light-emitting reflective spatial light modulator such as DMD, a transmissive spatial light modulator may be used, or a self-luminous image display element may be used. Note that a variable pattern forming apparatus may be used even when the pattern surface is placed horizontally.

In the above-described embodiment, the pupil intensity distribution at each point on the irradiated surface is adjusted substantially uniformly. However, the pupil intensity distribution at each point on the irradiated surface is not uniform. You may adjust it. Further, the pupil intensity distribution at each point on the irradiated surface may be adjusted to different predetermined distributions. For example, an exposure apparatus such as a line width error caused by the non-uniformity of the pupil intensity distribution of the exposure apparatus itself, a coating / development processing apparatus (coater developer) or a heating / cooling processing apparatus used in combination with the exposure apparatus in the photolithography process In order to correct line width errors caused by devices other than those described above, the pupil intensity distribution at each point on the irradiated surface may be adjusted to different predetermined distributions.

As will be described later, in the photolithography process in the semiconductor device manufacturing process, a photoresist (photosensitive material) film is formed on the surface of an object to be processed such as a wafer, and then a circuit pattern is exposed to the film and further developed. By doing so, a resist pattern is formed. This photolithography process is continuously provided integrally with a coating / development processing apparatus (coater / developer) having a resist coating processing unit for applying a resist to a wafer and a development processing unit for developing an exposed wafer. The exposure apparatus.

Such a coating and developing treatment apparatus includes, for example, a heat treatment apparatus and a cooling treatment apparatus that perform heat treatment such as heat treatment and cooling treatment on the wafer after forming a resist film on the wafer or before and after the development treatment. Have. Here, when the resist film thickness is not uniform in the wafer surface or the temperature distribution in the wafer surface is not uniform by these heat treatments, the distribution of the line width uniformity in the shot region is the wafer W. Depending on the position of the upper shot area, different properties may be exhibited. Even in an etching apparatus that etches a film to be etched under the resist pattern using the resist pattern as a mask, if the temperature distribution in the wafer surface is not uniform, the line width uniformity in the shot region The distribution may exhibit different properties depending on the position of the shot area on the wafer W.

The variation in the distribution of the line width uniformity in the shot area due to the position of the shot area on the wafer caused by such a coating and developing apparatus or an etching apparatus is a somewhat stable error distribution that does not depend on the shot position in the wafer ( Systematic error distribution). Therefore, in the exposure apparatus according to the above-described embodiment, by adjusting the pupil intensity distribution at each point on the irradiated surface to a predetermined distribution different from each other, the variation in the distribution of the line width uniformity in the shot region is changed. It is possible to correct.

The exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

Next, a device manufacturing method using the exposure apparatus according to the above-described embodiment will be described. FIG. 10 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 10, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a substrate of the semiconductor device (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the projection exposure apparatus of the above-described embodiment, the pattern formed on the mask (reticle) M is transferred to each shot area on the wafer W (step S44: exposure process), and the wafer W after the transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred (step S46: development process).

Thereafter, using the resist pattern generated on the surface of the wafer W in step S46 as a mask, processing such as etching is performed on the surface of the wafer W (step S48: processing step). Here, the resist pattern is a photoresist layer in which unevenness having a shape corresponding to the pattern transferred by the projection exposure apparatus of the above-described embodiment is generated, and the recess penetrates the photoresist layer. It is. In step S48, the surface of the wafer W is processed through this resist pattern. The processing performed in step S48 includes, for example, at least one of etching of the surface of the wafer W or film formation of a metal film or the like. In step S44, the projection exposure apparatus of the above-described embodiment performs pattern transfer using the wafer W coated with the photoresist as the photosensitive substrate, that is, the plate P.

FIG. 11 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 11, in the manufacturing process of the liquid crystal device, a pattern formation process (step S50), a color filter formation process (step S52), a cell assembly process (step S54), and a module assembly process (step S56) are sequentially performed. In the pattern forming process of step S50, a predetermined pattern such as a circuit pattern and an electrode pattern is formed on the glass substrate coated with a photoresist as the plate P using the projection exposure apparatus of the above-described embodiment. The pattern forming step includes an exposure step of transferring the pattern to the photoresist layer using the projection exposure apparatus of the above-described embodiment, and development of the plate P on which the pattern is transferred, that is, development of the photoresist layer on the glass substrate. And a developing step for generating a photoresist layer having a shape corresponding to the pattern, and a processing step for processing the surface of the glass substrate through the developed photoresist layer.

In the color filter forming process in step S52, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning direction. In the cell assembly process in step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembling process in step S56, various components such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

In the above-described embodiment, ArF excimer laser light (wavelength: 193 nm) or KrF excimer laser light (wavelength: 248 nm) is used as the exposure light. However, the present invention is not limited to this, and other suitable laser light sources. For example, the present invention can also be applied to an F ₂ laser light source that supplies laser light having a wavelength of 157 nm.

In the above-described embodiment, a so-called immersion method is applied in which the optical path between the projection optical system and the photosensitive substrate is filled with a medium (typically liquid) having a refractive index larger than 1.1. You may do it. In this case, as a method for filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a method for locally filling the liquid as disclosed in International Publication No. WO 99/49504, A method of moving a stage holding a substrate to be exposed as disclosed in Japanese Patent Laid-Open No. 6-124873 in a liquid bath, or a stage having a predetermined depth on a stage as disclosed in Japanese Patent Laid-Open No. 10-303114. A technique of forming a liquid tank and holding the substrate in the liquid tank can be employed. In the above-described embodiment, a so-called polarization illumination method disclosed in US Publication Nos. 2006/0170901 and 2007/0146676 can be applied.

In the above-described embodiment, the present invention is applied to the illumination optical system that illuminates the mask (or wafer) in the exposure apparatus. However, the present invention is not limited to this, and an object other than the mask (or wafer) is used. The present invention can also be applied to a general illumination optical system that illuminates the irradiation surface.

DESCRIPTION OF SYMBOLS 1 Beam transmission part 2 Light guide member 3 Spatial light modulator 4 Relay optical system 5 Micro fly eye lens 7 Condenser optical system 8 Mask blind 9 Imaging optical system 10 Illuminance distribution measurement part 11 Pupil intensity distribution measurement part LS Light source SU Space Light modulation unit CR Control unit M Mask PL Projection optical system W Wafer

Claims (17)

In the illumination optical system that illuminates the illuminated surface based on the light from the light source,
A spatial light modulator having a plurality of optical elements arranged two-dimensionally and individually controlled;
A condensing optical system that forms a predetermined light intensity distribution on an array surface of the plurality of optical elements of the spatial light modulator and a surface optically Fourier-transformed based on the light that has passed through the spatial light modulator; ,
An optical integrator having a plurality of unit wavefront division planes arranged two-dimensionally on the plane to be the Fourier transform;
The pupil intensity distribution formed on the illumination pupil based on the light from the spatial light modulator via the condensing optical system and the optical integrator is adjusted to a required distribution, and each of the plurality of unit wavefront division planes An illumination optical system comprising: a control unit that controls the spatial light modulator in order to adjust the light intensity distribution formed in each to a required distribution. The illumination optical system according to claim 1, wherein each of the plurality of unit wavefront dividing surfaces is optically conjugate with the irradiated surface. An illuminance distribution measurement unit that measures the illuminance distribution on the irradiated surface;
A pupil intensity distribution measuring unit that measures a pupil intensity distribution for each point on the irradiated surface;
The control unit controls postures of the plurality of optical elements of the spatial light modulator based on a measurement result of the illuminance distribution measurement unit and a measurement result of the pupil intensity distribution measurement unit. The illumination optical system according to 1 or 2. 4. The spatial light modulator according to claim 1, further comprising: a plurality of mirror elements arranged two-dimensionally; and a drive unit that individually controls and drives the postures of the plurality of mirror elements. The illumination optical system according to claim 1. The illumination optical system according to claim 4, wherein the driving unit continuously or discretely changes the directions of the plurality of mirror elements. The projection pupil is used in combination with a projection optical system that forms a surface optically conjugate with the irradiated surface, and the illumination pupil is at a position optically conjugate with an aperture stop of the projection optical system. The illumination optical system according to any one of 1 to 5. A pupil intensity distribution related to a predetermined point on the irradiated surface is defined as a first pupil intensity distribution, and a pupil intensity distribution related to another point different from the predetermined one point on the irradiated surface is set to a second 7. The light intensity distribution formed on each of the plurality of unit wavefront division planes so as to be a pupil intensity distribution is two or more types of light intensity distributions. The illumination optical system described. A pupil intensity distribution measuring unit that measures a pupil intensity distribution for each point on the irradiated surface;
The control unit sets the pupil intensity distribution related to a predetermined point on the irradiated surface measured by the pupil intensity distribution measuring unit as the first pupil intensity distribution, and is measured by the pupil intensity distribution measuring unit. The posture of the plurality of optical elements of the spatial light modulator is controlled so that a pupil intensity distribution related to another point different from the predetermined one point on the irradiated surface is a second pupil intensity distribution. The illumination optical system according to claim 7. An exposure apparatus comprising the illumination optical system according to claim 1 for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate. The exposure apparatus according to claim 9, further comprising a projection optical system that forms an image of the predetermined pattern on the photosensitive substrate. The illuminance distribution measurement unit measures the illuminance distribution on the image plane of the projection optical system,
The exposure apparatus according to claim 10, wherein the pupil intensity distribution measurement unit measures a pupil intensity distribution on a pupil plane of the projection optical system based on light transmitted through the projection optical system. An exposure step of exposing the predetermined pattern to the photosensitive substrate using the exposure apparatus according to any one of claims 9 to 11,
Developing the photosensitive substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer. In a control method for controlling a spatial light modulator having a plurality of optical elements that are incorporated in an illumination optical system that illuminates an irradiated surface based on light from a light source and is two-dimensionally arranged and individually controlled,
A condensing optical system that forms a predetermined light intensity distribution on an optically Fourier transform surface of the spatial light modulator and an array surface of the optical elements, and a two-dimensional array on the Fourier transform surface A first adjustment step of adjusting a pupil intensity distribution formed in the illumination pupil based on the light from the spatial light modulator via the optical integrator having a plurality of unit wavefront splitting surfaces to a required distribution;
And a second adjustment step of adjusting a light intensity distribution formed on each of the plurality of unit wavefront dividing surfaces to a required distribution. The control method according to claim 13, wherein the first adjustment step and the second adjustment step are performed simultaneously. A first setting step of setting a first target pupil intensity distribution that is a target of the pupil intensity distribution for a predetermined point on the irradiated surface;
A second setting step of setting a second target pupil intensity distribution that is a target of the pupil intensity distribution related to another point different from the predetermined one point on the irradiated surface,
In the first and second adjustment steps, the pupil intensity distribution related to the predetermined one point is set as the first target pupil intensity distribution, and the pupil intensity distribution related to the another point is set as the second target pupil intensity distribution. In addition, the pupil intensity distribution formed on the illumination pupil is adjusted, and the light intensity distribution formed on each of the plurality of unit wavefront division planes is adjusted respectively. Control method. A first partitioning step of partitioning the first target pupil intensity distribution according to the plurality of unit wavefront division planes;
A first light intensity calculation step of calculating a light intensity at a position corresponding to the predetermined one point in the partitioned first target pupil intensity distribution;
A second partitioning step of partitioning the second target pupil intensity distribution according to the plurality of unit wavefront division planes;
A second light intensity calculating step for calculating the light intensity at a position corresponding to the other one point in the partitioned second target pupil intensity distribution;
The light intensity to be formed on the plurality of unit wavefront dividing surfaces based on the light intensity at the position corresponding to the predetermined one point and the other one point calculated in the first and second light intensity calculation steps The control method according to claim 15, further comprising a step of calculating each distribution. In the illumination optical system that illuminates the illuminated surface based on the light from the light source,
A spatial light modulator having a plurality of optical elements arranged two-dimensionally and individually controlled;
A condensing optical system that forms a predetermined light intensity distribution on an array surface of the plurality of optical elements of the spatial light modulator and a surface optically Fourier-transformed based on the light that has passed through the spatial light modulator; ,
An optical integrator having a plurality of unit wavefront division planes arranged two-dimensionally on the plane to be the Fourier transform;
An illumination optical system comprising: a control unit that controls the spatial light modulator according to the control method according to any one of claims 13 to 16.

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