TWI645261B - Illumination optical system, lithography apparatus, and article manufacturing method - Google Patents

Abstract

An illumination optical system that illuminates the illuminated surface with light from the light source is provided. The illumination optical system includes an optical integrator disposed between the light source and the illuminated surface, and an optical filter having an adjustment unit for adjusting the intensity of the light incident on the optical integrator. An optical integrator is a rod-type optical integrator that reflects incident light on the inner surface. The illumination optical system changes the illuminance on the illumination surface by changing the position of the adjustment unit in a direction perpendicular to the optical axis of the illumination optical system.

Description

Illumination optical system, lithography apparatus, and article manufacturing method

[0001] The present invention relates to an illumination optical system, a lithography apparatus, and an article manufacturing method.

[0002] In an exposure apparatus for projecting a pattern formed on a mask onto a substrate on which a photosensitive material such as a resist layer is applied, it is required to improve illuminance uniformity on an illuminated surface such as a mask surface or a substrate surface. As a method of improving illuminance uniformity, an illumination optical system including a rod type optical integrator is known. The rod type optical integrator is used to superimpose the illumination light from the secondary light source formed by the number of times of the inner surface reflection in the rod body at the rod emitting end, thereby uniformizing the illuminance distribution on the rod emitting surface . [0003] However, in the illumination optical system including the rod-type optical integrator, there are various factors such as staining, eccentricity, and unevenness of the anti-reflection film of the optical system, and thus there is a result of illuminance distribution on the illuminated surface. Confirm the case of unevenness. To solve this problem, Patent Document 1 discloses a configuration in which a plurality of light amount adjustments are provided corresponding to a plurality of secondary light source images at a position that is optically conjugate with the emission surface of the rod-type optical integrator. unit. [0004] However, in the illumination optical system disclosed in Patent Document 1, when the angular distribution (hereinafter referred to as "effective light source distribution") of the illumination surface is determined, the illumination distribution correction amount on the illumination surface becomes fixed. Therefore, it is difficult to correct the illuminance unevenness (hereinafter referred to as "illuminance unevenness") which is unique to each machine body due to the film formation state of the antireflection film, the assembly accuracy, and the like. Further, in the case where the optical device is deteriorated by using the device for a long period of time and the illuminance unevenness changes over time, it is necessary to exchange the adjustment portion as appropriate. [Prior Art Document] [Patent Document] [0005] [Patent Document 1] Japanese Patent Laid-Open No. 2000-269114

[0006] According to an aspect of the present invention, an illumination optical system is provided that illuminates an illumination surface by light from a light source, and has an optical integrator disposed between the light source and the illumination surface, and is incident on a filter for an adjustment unit that adjusts an intensity of light of the optical integrator, wherein the optical integrator is a rod type optical integrator that reflects incident light on an inner surface, and the filter is included in the rod type optical integral a plurality of first regions in which the emission end faces of the device form images in the same direction, and a plurality of second regions in which the emission end faces have a mirror image relationship with respect to the image, and the adjustment portion is provided in at least the first region The region is changed by changing the position of the adjustment portion in a direction perpendicular to the optical axis of the illumination optical system to change the illuminance on the illumination surface.

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and the following embodiments are merely illustrative of specific examples of the implementation of the present invention. Further, all of the combinations of the features described in the following embodiments are not necessarily required to solve the problems of the present invention. <First Embodiment> Fig. 1 is a schematic view showing the configuration of an exposure apparatus 100 according to the present embodiment. The exposure apparatus 100 is, for example, a user of a photolithography program in the process of manufacturing a semiconductor device, for exposing (transferring) an image formed on a pattern of a mask R (mask) onto a wafer W as a substrate. Type exposure device. In FIG. 1, the Z axis is taken along the normal direction of the wafer W, and the X axis and the Y axis are taken in directions perpendicular to each other in a plane parallel to the wafer W plane. The exposure apparatus 100 includes an illumination optical system 101, a mask stage 102, a projection optical system 103, a wafer stage 104, and a control unit 105. [0010] The illumination optical system 101 adjusts light (light beam) from the discharge lamp 1 of the light source, and illuminates the mask R as an illumination area. The discharge lamp 1 may be, for example, an ultrahigh pressure mercury lamp that supplies light such as i-rays (wavelength 365 nm). Further, not limited thereto, for example, a KrF excimer laser that supplies light of a wavelength of 248 nm, an ArF excimer laser that supplies light of a wavelength of 193 nm, and an F2 laser that supplies light of a wavelength of 157 nm may be used. Further, when the illumination optical system 101 and the projection optical system 103 are configured by a catadioptric system or a reflection system, a charged particle beam such as an X-ray or an electron beam can be used as the light source. [0011] The mask R is, for example, a master plate made of quartz glass, and is formed with a pattern (for example, a circuit pattern) to be transferred onto the wafer W. The mask stage 102 holds the mask R and is movable in the respective axial directions of X and Y. The projection optical system 103 projects the light passing through the mask R onto the wafer W at a predetermined magnification. The wafer W is a substrate made of, for example, a single crystal germanium coated with a resist layer (photosensitive material) on the surface. The wafer table 104 holds the wafer W through a wafer jig (not shown), and is movable in the respective axial directions of X, Y, and Z (sometimes including ωx, ωy, and ωz in individual rotation directions). The wafer table 104 is driven by the wafer table driving unit 114. The illumination optical system 101 sequentially includes the elliptical mirror 2, the first relay optical system 3, the optical integrator 4, and the second relay optical system 5 from the discharge lamp 1 to the mask R as an illumination region. The elliptical mirror 2 is a condensing mirror that condenses light (light beam) emitted from the discharge lamp 1 at the second focus position F2. The light-emitting portion in the tube portion of the discharge lamp 1 is disposed, for example, in the vicinity of the first focus F1 of the elliptical mirror 2. The first relay optical system 3 as the imaging optical system includes a lens front group 3a (first lens) formed of a single or a plurality of lenses, and a lens rear group 3b formed of a single or a plurality of lenses (second lens). The front group 3a of the lens causes the light from the light source to be parallel light. The lens rear group 3b condenses the light that has passed through the lens rear group 3a as parallel light to the incident end surface 4a of the optical integrator 4. The second focus position F2 and the incident end surface 4a of the optical integrator 4 are optically conjugated through the lens front group 3a and the lens rear group 3b. In the present embodiment, the illumination optical system 101 includes, in particular, the optical axis of the optical system of the first relay optical system 3, the optical integrator 4, and the second relay optical system 5 in the Z-axis direction. [0013] In the present embodiment, the optical integrator 4 is a rod-type optical integrator that reflects incident light on the inner surface and forms a plurality of secondary light source images according to the number of reflections. The shape of the optical integrator 4 is, for example, a quadrangular prism. That is, the shape of the incident end face and the exit end face parallel to the XY plane of the optical integrator 4 is a rectangle similar to the illuminated surface. Nevertheless, such a shape is merely illustrative and is not intended to impede the application of a member having the same function as the optical integrator 4. For example, the optical integrator 4 may be constituted by a hollow rod that forms a reflecting surface inside. Further, the cross-sectional shape of the incident end surface 4a and the output end surface 4b of the optical integrator 4 on the XY plane may be a polygon other than a square. [0014] Between the discharge lamp 1 and the optical integrator 4, the filter 6 is disposed perpendicular to the optical axis in the vicinity of the conjugate plane S1 which is conjugate with the mask R, that is, the wafer W. The filter 6 is configured to be movable two-dimensionally along the XY plane, and the movement is performed by, for example, the filter driving unit 7. The filter 6 is included in the first relay optical system 3, for example, as shown in Fig. 1, and is disposed between the lens front group 3a and the lens rear group 3b. The filter 6 has a plurality of adjustment sections that are set in accordance with the number of secondary light source images formed by the optical integrator 4, and are adjusted in intensity of light incident on the optical integrator 4. . The optical effect of the filter 6 will be described in detail later. [0015] The lens rear group 3b is disposed at a position where the focal length is separated from the position of the virtual image plane S2 of the secondary light source formed by the optical integrator 4, and is emitted from the filter 6 substantially parallel to the optical axis. , temporarily concentrated on this virtual image surface S2. [0016] The incident end surface 4a of the optical integrator 4 is disposed in the vicinity of the virtual image plane S2. The illumination light collected by the lens rear group 3b is reflected and reflected on the inner surface of the optical integrator 4 several times. The illumination light emitted from the optical integrator 4 is emitted as a virtual image from a discrete secondary light source corresponding to the number of reflections. Therefore, the angle of the illumination light emitted from the optical integrator 4 corresponds to an emission angle of the illumination light from the virtual image of the secondary light source disposed on the virtual image plane S2. [0017] The emission end surface 4b of the optical integrator 4 is superimposed on a plurality of light source images arranged on the virtual image plane S2, and is irradiated in the same manner. The light emitted from the emission end surface 4b of the optical integrator 4 is transmitted through the second relay optical system 5, and then illuminates the mask R as an illumination surface. The second relay optical system 5 includes a lens front group 5a formed of a single or a plurality of lenses that make the light from the emission end surface 4b of the optical integrator 4 into parallel light. The lens front group 5a is configured to be movable in the optical axis direction (Z-axis direction) of the second relay optical system 5. The second relay optical system 5 further includes a lens rear group 5b formed by singular or plural lenses that condense light that is adjusted to be parallel light by the lens front group 5a on the illumination surface. The movement of the lens front group 5a is performed by the lens driving unit 51. The lens front group 5a is moved in the optical axis direction so that the distortion can be changed without substantially changing the focal length. By this action, the movement of the lens front group 5a is utilized so that the peripheral illumination can be improved. [0018] In the present embodiment, the emission end surface 4b of the optical integrator 4 is disposed at the front focus position of the lens front group 5a, and the emission end surface 4b of the optical integrator 4 is optically connected to the mask R as the illumination surface. Conjugation. Further, strictly speaking, in order to avoid foreign matter on the emission end surface 4b of the optical integrator 4, the position of the emission end surface 4b can be slightly shifted from the conjugate. Further, the light emitted from the mask R, that is, the image of the mask pattern is transferred onto the wafer W via the projection optical system 103. [0019] The illuminance distribution measuring unit 115 measures the illuminance distribution on the mask R as the illumination surface. The control unit 105 controls the discharge lamp 1, the filter drive unit 7, the lens drive unit 51, the wafer stage drive unit 114, and the illuminance distribution measurement unit 115. The control unit 105 may include a memory unit 105a that stores various materials required for control. [0020] Next, the optical effect of the filter 6 will be described. 2 is a view schematically showing the relationship between a plurality of adjustment portions provided on the filter and a plurality of secondary light sources formed by the optical integrator 4. Fig. 2 is a view showing the light path of the illumination light emitted from the optical filter 6 in parallel with the optical axis. The adjustment portion 60 provided on the optical axis of the optical filter 6 adjusts the intensity of the light beam from the secondary light source 40 that is not reflected on the inner surface of the optical integrator 4. Further, the pair of adjustment portions 61a and 61b adjacent to both outer sides of the adjustment unit 60 adjust the intensity of the light beam from the secondary light source images 41a and 41b that are reflected once on the inner surface of the optical integrator 4. Further, the pair of adjustment portions 62a and 62b adjacent to the outer sides of the adjustment portions 61a and 61b are the intensity of the light beam from the secondary light source images 42a and 42b which are reflected twice on the inner surface of the optical integrator 4. Make adjustments. According to this configuration, the transmittance of the individual light beams of the plurality of secondary light sources formed by the optical integrator 4 can be independently controlled. [0021] The adjustment portions 60, 61a, 61b, 62a, and 62b are disposed in the vicinity of the conjugate plane S1 conjugate with the emission end surface 4b of the optical integrator 4. Therefore, the shape of one adjustment portion corresponds to the illumination region on the mask R or the wafer W of FIG. 1, and the transmittance distribution of the adjustment portions 60, 61a, 61b, 62a, and 62b is reflected on the wafer W. The illuminance distribution of the illuminated area above. 3A is a view for explaining an imaging relationship between each adjustment portion of the optical filter 6 and the emission end surface 4b of the optical integrator 4. In the optical integrator 4, the light beams from the adjacent secondary light sources are inverted. Therefore, when the direction of the image formed by the emission end surface 4b of the optical integrator 4 becomes "F", the images of the adjacent adjustment portions are reversed and have a mirror image relationship with each other. 3B is a schematic view of the optical filter 6 disposed in the vicinity of the conjugate plane S1 as seen from the incident side. Here, a pattern filter (or a light-shielding member) is used as the adjustment unit. In the present embodiment, the plurality of pattern filters constituting the plurality of adjustment units are disposed at predetermined positions on the filter corresponding to the mirror image relationship of the plurality of secondary light source images of the optical integrator 4. The filter 6 includes a plurality of first regions A and B and a plurality of second regions belonging to regions other than the first region. Here, the plurality of first regions A and B are regions in which the imaging end faces 4b of the optical integrator 4 form images in the same direction. Further, the plurality of second regions are regions in which the image of the image having a mirror image relationship with respect to the image of the first region is formed on the emission end surface 4b of the optical integrator 4. In the present embodiment, the surface of the optical filter 6 corresponds to a plurality of secondary light source images of the optical integrator 4, and the rectangular pattern filters 6A and 6B are disposed in the plurality of first regions A and B, respectively. Further, the pattern filters 6A and 6B may be disposed in at least a part of the plurality of first regions A and B, not all of them. [0024] In the present embodiment, circular pattern filters having different sizes are disposed as the pattern filters 6A and 6B, so that each pattern filter portion has the same as shown in FIGS. 4(A) and (B). effect. The diameter, transmittance, arrangement, and the like of each of the pattern filters are made appropriate so that the image is finally approximated to the illuminated surface, as shown in Fig. 4(C) showing the sum of Figs. 4(A) and (B). The effect of increasing the illuminance of the peripheral portion of the illuminated surface by the ratio of the second power. [0025] In general, in the illumination optical system of the projection exposure apparatus, when the uniformity of the numerical aperture of the illuminated surface and the uniformity of the illuminance distribution are simultaneously established, due to the angular characteristics of the anti-reflection film for the lens There is a tendency for the surrounding illuminance to decrease. Therefore, the filter having the function of improving the illuminance of the periphery as in the present embodiment is effective for correcting the illuminance distribution. Further, the light beam incident on the optical integrator 4 is adjusted to have a symmetrical illuminance distribution with respect to the optical axis. Thereby, the effective light source distribution of the illuminated surface is symmetrical with respect to the chief ray, so that no image shift occurs for defocusing. Thereby, good exposure under telecentricity can be achieved. [0027] In the event that the illumination light incident on the optical integrator 4 has an asymmetric illuminance distribution with respect to the optical axis, the symmetry of the effective light source distribution is lost, and the image performance is affected by the deviation of the telecentricity. . On the other hand, according to the present embodiment, the arrangement of the pattern filters is optically axisymmetric, so that there is almost no deviation in telecentricity. In the present embodiment, two types of pattern filters 6A and 6B are used as the adjustment unit. However, for example, by changing the density of the fine dot pattern, it is possible to form a pattern of one type and an image height. The proportional illuminance distribution of the power. [0029] In the following, a correction method relating to illuminance unevenness as shown in FIG. 5A will be described. The illuminance unevenness of FIG. 5A can be decomposed into: illuminance unevenness as shown in FIG. 5B; the illuminance which is symmetrical in the optical axis symmetry as shown in FIG. 5C, and the illuminance which decreases as the periphery is decreased All. These are separated by calculating the image height illuminance and the tilt component from the illuminance distribution. [0030] First, a method of correcting the illuminance unevenness in the inclined shape of FIG. 5B will be described. As described above, the optical filter 6 of the present embodiment has an effect of increasing the illuminance of the peripheral portion in proportion to the substantially square of the image height. At this time, when the incident end surface 4a of the optical integrator 4 corresponds to the illuminated surface and the normalized XY coordinate system is adopted, the effect z of the illuminance distribution adjustment achieved by the filter 6 is recorded as z=a. (x ² +y ² ). Here, a is a constant. The pattern filters 6A and 6B of the optical filter 6 are disposed on at least a part of the plurality of first regions A and B which form images in the same direction in the emission end surface 4b of the optical integrator 4. The filter 6 is movable in a direction along a plurality of first regions A, B, and a plurality of second regions in a region other than the other, or may be moved in a direction along the XY plane. That is, the position of the filter 6 in the direction (X direction or Y direction) perpendicular to the optical axis (Z axis) of the illumination optical system can be changed. Here, even if the filter 6 is moved in the direction along the XY plane, the effects of the illuminance distribution change on the illuminated surface given by the pattern filters 6A, 6B are not eliminated from each other. Therefore, the effect z' of the illuminance distribution adjustment achieved by the filter 6 when the filter 6 is moved by the predetermined distance δ in the X direction and the Y direction is denoted by z'=a ((x+δ) ) ² + (y + δ) ² ). Here, a is a constant. That is, since the first term of x and y depending on δ occurs, a illuminating distribution of a slope can be generated. [0033] FIG. 6 is a flow chart showing the order of correction of the illuminance unevenness in a slanting manner. In S601, the control unit 105 calculates the illuminance unevenness on the illuminated surface (the illuminance unevenness measurement 1) based on the illuminance distribution data measured by the illuminance distribution measuring unit 115. When the maximum value of the illuminance value on the illuminated surface is Smax and the minimum value is Smin, the illuminance unevenness S is calculated by, for example, the following equation. S=(Smax−Smin)/(Smax+Smin) [0034] Thereafter, the control unit 105 moves the filter 6 in the X direction by a predetermined distance δ in S602, and measures the illuminance unevenness on the illuminated surface in S603 ( Illumination unevenness measurement 2). Next, the control unit 105 moves the filter 6 in the Y direction by a predetermined distance δ in S604, and measures the illuminance unevenness on the illuminated surface in S605 (the illuminance unevenness measurement 3). Thereafter, the control unit 105 calculates the amount of change in illuminance unevenness from the results of the illuminance unevenness measurement 1, 2, and 3 in S606, and stores it in the storage unit 105a. This amount of change corresponds to the slope of the above-described oblique illuminance distribution. [0035] Next, in S607, the control unit 105 calculates the moving direction and the moving amount of the filter 6 based on the amount of change calculated in S606. Further, the control unit 105 passes through the filter driving unit 7 to move the filter 6 by the calculated amount of movement in the calculated direction. After that, in S609, the control unit 105 measures the illuminance unevenness on the illuminated surface again (the illuminance unevenness measurement 4), and in S610, it is confirmed whether or not the illuminance unevenness falls within a predetermined allowable range. Here, if the illuminance unevenness falls within the allowable range, the process ends. On the other hand, if the illuminance unevenness does not fall within the allowable range, the process proceeds to S611, and the result of the illuminance unevenness measurement 4 is returned, and the process returns to S607, and the moving direction and the moving amount of the filter 6 are calculated. [0037] Next, a method of correcting the illuminance unevenness of the optical axis symmetry of FIG. 5C will be described with reference to the flowchart of FIG. 7. When the illuminance unevenness of the optical axis symmetry occurs, the peripheral illuminance correction amount is adjusted. As described above, the second relay optical system 5 has a configuration in which the lens front group 5a is moved in the optical axis direction so that the distortion is changed without substantially changing the focal length. Thereby, the movement of the lens front group 5a is utilized so that the peripheral illuminance can be improved. [0038] In S701, the control unit 105 obtains the amount of change in the illuminance of the outermost peripheral portion of the illuminated surface when the lens front group 5a is moved by the predetermined distance δ in the optical axis direction by the illuminance distribution measuring unit 115. The amount of change is stored in the memory unit 105a (illuminance unevenness measurement 1). In addition, this S701 can also be performed in advance through simulation or the like. In S702, the control unit 105 calculates the amount of movement in the optical axis direction of the lens front group 5a based on the amount of change. In S703, the control unit 105 transmits the calculated movement amount by moving the lens front group 5a in the optical axis direction through the lens driving unit 51. Then, in S704, the control unit 105 obtains the amount of change in the illuminance of the outermost peripheral portion of the illuminated surface when the lens front group 5a is moved by the predetermined distance δ in the optical axis direction (the illuminance unevenness measurement 2). At S705, it is confirmed whether the fluctuation amount falls within a predetermined allowable range. When the amount of variation falls within the allowable range, the process ends. On the other hand, if the fluctuation amount does not fall within the allowable range, the process proceeds to S706, and the result of the illuminance unevenness measurement 2 is returned, and the process returns to S703, and the amount of movement of the filter 6 is calculated. In this manner, the control unit 105 returns the amount of movement of the control filter 6 so that the illuminance unevenness calculated from the illuminance distribution measured by the illuminance distribution measuring unit 115 falls within the allowable range. [0040] By performing both the movement of the filter 6 in the control sequence according to FIG. 6 described above and the driving of the lens front group in the control sequence of FIG. 7, more precise correction can be performed. At this time, the control sequence of FIG. 6 and the control sequence of FIG. 7 under the transmission control unit 105 may be executed in series in time series, or may be performed in parallel. [0041] Further, the execution result of the control sequence of FIG. 6 and the control sequence of FIG. 7 can be memorized in the memory unit 105a. When the same lighting condition is performed again, the execution result is called from the memory unit 105a to drive each element to the optimum position. Thereby, the order of the illuminance unevenness and the illuminance unevenness of the concentric circles (the illuminance unevenness of the optical axis symmetry) can be quickly corrected in the order of FIG. 6 and FIG. 7 . Further, when the illumination optical system is used for a long period of time, it is conceivable that the transmittance of any one of the lenses in the apparatus is deteriorated, and unevenness in illuminance in which the rotation is asymmetric is generated. In such a case, it is also possible to perform the correction of the illuminance unevenness and the concentric illuminance unevenness (the optical axis symmetry illuminance unevenness) by performing the control sequence of FIGS. 6 and 7 again. Further, in the Japanese Patent Laid-Open Publication No. 2001-135564, a filter is disposed in the vicinity of an incident surface of an optical integrator in which a plurality of microlenses are arranged at a predetermined distance in two dimensions. The optical filter has a light amount adjusting unit that can adjust the amount of transmitted light in a plurality of regions corresponding to a plurality of minute lenses constituting the optical integrator. With such a configuration, the filter can be moved in the XY plane to control the illuminance unevenness. [0044] However, an optical integrator in which a plurality of minute lenses are arranged in two dimensions at a predetermined distance is generally expensive, so that the rod type optical integrator according to the present embodiment is relatively low in cost. In the configuration of the present embodiment using the rod type optical integrator, the arrangement of the respective adjustment units is determined by the imaging relationship as shown in FIG. 3A. Specifically, the plurality of adjustment units are arranged in the same direction so that the directions of the images formed in the respective adjustment portions of the emission end faces of the rod-type optical integrator are transmitted in the same direction by the light transmitted through the plurality of adjustment portions. On the light. According to this, illuminance unevenness control can be performed. <Second Embodiment> Next, an illumination optical system according to a second embodiment will be described. The schematic configuration of the device is as in Figure 1. Fig. 3C is a schematic view of the optical filter 6 according to the present embodiment as seen from the incident side. The surface of the filter 6 corresponds to a plurality of secondary light source images of the optical integrator 4, and the rectangular pattern filter 6C is disposed in a plurality of first regions C, and the rectangular pattern filter 6D is disposed in plural The second area D. Further, the pattern filters 6C and 6D may be arranged in a region of at least a part of the plurality of first regions C and the plurality of second regions D, not all of them. Here, the plurality of first regions C are regions in which images of the same direction are formed on the emission end faces 4b of the optical integrator 4. Further, the plurality of second regions D are regions in which the imaging end faces 4b of the optical integrator 4 form an image having a mirror image relationship with respect to the images of the plurality of first regions C. In the present embodiment, the pattern filter 6C has an effect of increasing the illuminance of the peripheral portion of the illuminated surface in proportion to the approximate second power of the image height as shown in FIG. 8A. Further, the pattern filter 6D has an opposite characteristic, that is, it has an effect of reducing the illuminance of the peripheral portion in proportion to the approximate second power of the image height as shown in FIG. 8B. By the combination of the pattern filters 6C and 6D, the effects of the change in the overall illuminance distribution are eliminated from each other. [0047] Hereinafter, a method of correcting the illuminance unevenness in the inclined shape as shown in FIG. 9A will be described. When the incident end surface 4a of the optical integrator 4 corresponds to the illuminated surface, and the normalized XY coordinate system is adopted, the effect z of the filter 6 is simply z=ax ² -ax when it is only one dimension in the X direction. ² =0, does not affect the illuminance distribution. Here, a is a constant. [0048] The effect z' when the filter 6 is moved by a predetermined distance δ in the X direction is changed in the direction of the pattern filters 6C and 6D δ, so that z'=a(x+δ) ² -a( X-δ) ² . That is, since the first term of x depending on δ is generated, an oblique illuminance distribution can be generated. In the present embodiment, also in the same manner as the flowchart of FIG. 6, the illuminance unevenness in the oblique shape can be corrected in a flat manner as shown in FIG. 9B. As described above, when the peripheral illuminance reduction of the secondary shape is small and the illuminance unevenness of the inclined shape is dominant, the configuration of the adjustment unit of the present embodiment is effective for correcting the illuminance distribution. <Third Embodiment> Next, an illumination optical system according to a third embodiment will be described. In the present embodiment, the effects of the pattern filters 6C and 6D in the second embodiment are different. The pattern filter 6C in the present embodiment has an effect of changing as if the illuminance distribution and the image height are approximately three powers as shown in FIG. 10A. Further, the pattern filter 6D has an opposite characteristic, that is, it has an effect of changing as in the approximate third power of the image height as shown in Fig. 10B. By the combination of the pattern filters 6C and 6D, the effects of the change in the overall illuminance distribution are eliminated from each other. [0051] As in the second embodiment, the effect z of the filter 6 indicates that z = ax ^{3 -} ax ³ = 0 when only the X direction is one dimension, and the illuminance distribution is not affected. Here, a is a constant. [0052] The effect z' when the filter 6 is moved by a predetermined distance δ in the X direction is changed in the direction of the pattern filters 6C and 6D δ, so that z'=a(x+δ) ³ -a( X-δ) ³ . In the present embodiment, since the second term of x depending on δ occurs, a concentric circular second illuminance distribution can be generated. In the present embodiment, it is also possible to perform the correction in the same manner as the flowchart of FIG. 6 so that the illuminance distribution of the secondary shape of FIG. 11A is flat as shown in FIG. 11B. In the case where the illuminance unevenness is not inclined, and the concentric circular illuminance unevenness is dominant, the configuration of the adjustment unit according to the present embodiment is effective for correcting the illuminance distribution. In addition, even if the illuminance distribution to be corrected is a high-order shape of three times or later, the illuminance unevenness correction can be performed by setting the transmittance distribution of the pattern filter as appropriate. According to each of the above embodiments, it is advantageous to provide an improvement in correction performance for illuminance unevenness. [Embodiment of the article manufacturing method] The article manufacturing method according to the embodiment of the present invention is, for example, an article suitable for manufacturing a micro device such as a semiconductor device or an element having a fine structure. The article manufacturing method according to the present embodiment includes a program for transferring a pattern of a main board on a substrate by the above-described photolithography apparatus (exposure apparatus, imprint apparatus, drawing apparatus, etc.), and processing a substrate on which the program is transferred. program. Further, such a manufacturing method includes other well-known procedures (oxidation, film formation, vapor deposition, doping, planarization, etching, resist peeling, dicing, bonding, encapsulation, etc.). The article manufacturing method of the present embodiment is advantageous for at least one of performance, quality, productivity, and production cost of the article compared to the conventional method. The present invention is not limited to the embodiments described above, and various modifications and changes can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are attached to disclose the scope of the invention.

[0057]

100‧‧‧Exposure device

101‧‧‧Lighting optical system

1‧‧‧discharge lamp

2‧‧‧Elliptical mirror

3‧‧‧1st relay optical system

3a‧‧‧Last lens group

3b‧‧‧Lens group

4‧‧‧Optical integrator

4a‧‧‧Injected end face

4b‧‧‧ shot end face

40‧‧‧Secondary light source

41a‧‧‧Secondary light source image

41b‧‧‧Secondary light source image

42a‧‧‧Secondary light source image

42b‧‧‧Secondary light source image

5‧‧‧2nd relay optical system

5a‧‧‧Last lens group

5b‧‧‧Lens group

51‧‧‧ lens drive unit

6‧‧‧ Filter

6A‧‧‧ pattern filter

6B‧‧‧ pattern filter

6C‧‧‧ pattern filter

6D‧‧‧ pattern filter

60‧‧‧Adjustment Department

61a‧‧‧Adjustment Department

61b‧‧‧Adjustment Department

62a‧‧‧Adjustment Department

62b‧‧‧Adjustment Department

7‧‧‧Filter drive unit

102‧‧‧mask table

103‧‧‧Projection optical system

104‧‧‧ Wafer

105‧‧‧Control Department

105a‧‧‧Memory Department

114‧‧‧ Wafer Drive Department

115‧‧‧Illuminance Distribution Measurement Department

F1‧‧‧1st focus

F2‧‧‧2nd focus position

R‧‧‧Photo Mask

S1‧‧‧conjugate surface

S2‧‧‧ virtual image

W‧‧‧ wafer

[FIG. 1] A diagram showing the configuration of an exposure apparatus. FIG. 2 is a schematic view showing the relationship between the adjustment unit and the secondary light source. FIG. FIG. 3A is a view showing an imaging relationship between an adjustment portion and an exit end surface of an optical integrator. FIG. FIG. 3B is a diagram showing an arrangement example of an adjustment portion on the optical filter. FIG. FIG. 3C is a diagram showing an arrangement example of an adjustment portion on the optical filter. FIG. Fig. 4 is a view for explaining the action of the filter. FIG. 5A is a diagram illustrating a method of correcting illuminance unevenness. FIG. FIG. 5B is a diagram for explaining a method of correcting illuminance unevenness. FIG. 5C is a diagram illustrating a method of correcting illuminance unevenness. Fig. 6 is a flow chart showing a procedure for correcting the inclination unevenness of illumination. [Fig. 7] A flow chart showing the order of correction of the illuminance unevenness of the optical axis symmetry. Fig. 8A is a view for explaining the action of the filter. Fig. 8B is a view for explaining the action of the filter. FIG. 9A is a diagram for explaining a method of correcting illuminance unevenness. FIG. 9B is a diagram for explaining a method of correcting illuminance unevenness. Fig. 10A is a view for explaining the action of the filter. Fig. 10B is a view for explaining the action of the filter. Fig. 11A is a view for explaining the action of the filter. Fig. 11B is a view for explaining the action of the filter.

Claims (10)

An illumination optical system that illuminates an illuminated surface by using light from a light source, comprising: an optical integrator disposed between the light source and the illuminated surface; and a filter having an optical integrator incident thereon The adjustment unit for adjusting the intensity of the light; wherein the optical integrator is a rod type optical integrator that reflects incident light on the inner surface, and the filter includes a plurality of first regions and a plurality of second regions, the plurality The first region forms an image in the same direction as the emission end surface of the rod-type optical integrator, and the plurality of second regions form an image having a mirror image relationship with respect to the image on the emission end surface, and the adjustment portion is not The second region is provided in the plurality of first regions, and the image formed on the emission end surface of the rod-type optical integrator by light transmitted from the adjustment portions provided in the plurality of first regions is transmitted through The light of the plurality of second regions is formed on the output end surface of the rod-type optical integrator, and the illumination surface is illuminated and transmitted. Adjusting the position of the portion in the direction perpendicular to the optical axis of the illumination optical system, the change is such that the illuminance of the illuminated surface. An illumination optical system that illuminates an illuminated surface by using light from a light source, comprising: an optical integrator disposed between the light source and the illuminated surface; and a filter having an optical integrator incident thereon The adjustment unit for adjusting the intensity of the light; wherein the optical integrator is a rod type optical integrator that reflects incident light on the inner surface, and the filter includes a plurality of first regions and a plurality of second regions, the plurality The first region forms an image in the same direction as the emission end surface of the rod-type optical integrator, and the plurality of second regions form an image having a mirror image relationship with respect to the image on the emission end surface, and the adjustment portion is disposed. a part of the plurality of first regions and a part of the plurality of second regions, the number of the adjustment portions provided in a part of the plurality of first regions, and the adjustment of a part of the plurality of second regions The number of the portions is the same, and is formed in the rod-type optical integrator by transmitting light from the adjustment portions provided in the plurality of first regions. An image of the end surface and an image formed on the emission end surface of the rod-type optical integrator by light from the adjustment unit provided in the plurality of second regions, and illuminating the illumination surface to pass through the first region The aforementioned illumination adjusted by the adjustment unit The characteristics of the illuminance distribution on the surface are different from the characteristics of the illuminance distribution on the illumination surface adjusted by the adjustment unit of the second region, and the adjustment is performed by changing the direction perpendicular to the optical axis of the illumination optical system. The position of the part changes the illuminance on the illuminated surface. An illumination optical system according to claim 1 or 2, further comprising: a first relay optical system disposed between the light source and the optical integrator, and a light guide from the light source In the optical integrator, the first relay optical system includes a first lens that causes light from the light source to be parallel light, and a light that is transmitted through the first lens to be parallel light to be incident on the optical integrator. In the second lens of the end surface, the filter is disposed between the first lens and the second lens. The illumination optical system according to claim 1 or 2, further comprising: a measurement unit that measures the illuminance distribution on the illumination surface; and the illuminance distribution measured by the measurement unit is changed to change the filter position. The illumination optical system according to claim 4, further comprising: a control unit that controls driving of the filter, wherein the control unit calculates the illuminance calculated from the illuminance distribution measured by the measurement unit. Feedback control that falls within the allowable range The driving of the aforementioned filter. The illumination optical system of claim 5, further comprising a second relay optical system disposed between the optical integrator and the illumination surface, and from the optical integrator The light guide of the emission end surface is directed to the illumination surface, and the second relay optical system is configured to include a third lens that causes the light from the emission end surface of the optical integrator to be parallel light, that is, includes a movable In the third lens in the optical axis direction of the second relay optical system, the control unit is configured to feedback control such that the illuminance unevenness calculated from the illuminance distribution measured by the measurement unit falls within an allowable range. Driving of the third lens described above. The illumination optical system according to claim 1 or 2, wherein the light from the first region in the first region is reflected on an inner surface of the rod-type optical integrator to be emitted from an end surface of the rod-type optical integrator The area where the image is formed. The illumination optical system according to claim 1 or 2, wherein, in the first region, light from the first region is not reflected on an inner surface of the rod-type optical integrator, and the rod-shaped optical integral is The exit end surface of the device forms an image region, and the adjustment portion is not provided. A lithographic apparatus for forming a pattern of a main board on a substrate, comprising: an illumination optical system according to claim 1 or 2 for illuminating the main board disposed on an illuminated surface; projecting a projection of the pattern onto the substrate Optical system. An article manufacturing method comprising: a program for forming a pattern on a substrate by using a lithography apparatus according to claim 9; a program for processing a substrate on which the pattern is formed by the program; wherein the article is obtained from the processed substrate .