Optical filter unit, illumination unit, exposure device and exposure method

Abstract

The optical filter unit includes a plurality of optical filters disposed on an optical axis of an illumination optical system that illuminates a surface to be irradiated, the plurality of optical filters including a first optical filter having a first transmittance distribution and a second optical filter having a second transmittance distribution. The first transmittance distribution is formed in a first direction of an orthogonal coordinate system in a plane orthogonal to the optical axis of the illumination optical system, in accordance with a first function represented by an n-order equation having coordinates in the first direction as variables, where n is a natural number of 2 or more, and n is a natural number of 1 or more. The relative position of the first filter and the second filter can be changed at least in the first direction.

Description

Technical Field

[0001] This invention relates to a filter unit, an illumination unit, an exposure apparatus, and an exposure method. Background Technology

[0002] In recent years, liquid crystal display panels have been widely used as display components in personal computers, televisions, and other devices. Liquid crystal display panels are manufactured by forming circuit patterns of thin-film transistors on a plate (glass substrate) using a photolithography method. As the apparatus used for this photolithography process, an exposure apparatus is used to project the original pattern formed on a mask onto a photoresist layer on the plate via a projection optics system (for example, Patent Document 1).

[0003] The goal is to improve the uniformity of illumination from the exposed light.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-21712 Summary of the Invention

[0007] According to the first disclosure, the filter unit includes a plurality of filters disposed on the optical axis of an illumination optical system illuminating an illuminated surface, wherein the plurality of filters includes a first filter having a first transmittance distribution and a second filter having a second transmittance distribution, the first transmittance distribution being formed in a first direction of an orthogonal coordinate system in a plane orthogonal to the optical axis of the illumination optical system according to a first function expressed by an nth-degree equation (n is a natural number of 2 or more) with coordinates in the first direction as variables, and the relative position of the first filter and the second filter being changeable at least in the first direction.

[0008] According to the second disclosure, the illumination unit includes an optical integrator for incident light emitted from the light source and the aforementioned filter unit, wherein light emitted from the optical integrator is incident on the filter unit.

[0009] According to the third disclosure, the exposure apparatus includes: a plurality of the aforementioned illumination units; and

[0010] Multiple projection optical units, corresponding to the multiple illumination units, project a pattern image of a mask illuminated by the multiple illumination units onto a photosensitive substrate. The multiple projection optical units include a first projection optical unit and a second projection optical unit, and the exposure area of ​​the first projection optical unit partially overlaps with the exposure area of ​​the second projection optical unit.

[0011] According to the fourth disclosure, the exposure method is an exposure method using the above-described exposure apparatus, comprising: illuminating the mask using the illumination unit; and projecting the pattern image of the mask onto the photosensitive substrate using the projection optics unit.

[0012] According to the fifth disclosure, the filter unit includes a plurality of filters disposed on the optical axis of an optical system. The plurality of filters include a first filter having a first transmittance distribution and a second filter having a second transmittance distribution. The first transmittance distribution is non-uniform in a first direction of an orthogonal coordinate system in a plane orthogonal to the optical axis of the optical system, and the second transmittance distribution is non-uniform in the first direction. The relative positions of the first filter and the second filter are changeable at least in the first direction.

[0013] According to the sixth disclosure, the illumination unit includes an optical integrator for incident light emitted from the light source and the aforementioned filter unit for incident light emitted from the optical integrator.

[0014] According to the method disclosed in the 7th disclosure, the exposure apparatus includes a plurality of the above-mentioned illumination units and a plurality of projection optical units corresponding to the plurality of illumination units, the plurality of projection optical units including a first projection optical unit and a second projection optical unit, wherein the exposure area of ​​the first projection optical unit partially overlaps with the exposure area of ​​the second projection optical unit.

[0015] According to the method disclosed in the 8th disclosure, the exposure method uses the above-described exposure apparatus, and the exposure method includes: illuminating the mask using the plurality of illumination units; and projecting the pattern image of the mask onto the photosensitive substrate using the plurality of projection optical units.

[0016] According to the ninth disclosure, the filter unit includes a plurality of filters disposed on the optical axis of an optical system. The plurality of filters includes a first filter, a second filter, and a third filter. The first filter has a first transmittance distribution that is non-uniform in a first direction intersecting the optical axis in the region where illumination light is incident. The second filter has a second transmittance distribution that is non-uniform in the first direction and different from the first transmittance distribution in the region where illumination light is incident. The third filter has a second transmittance distribution that is non-uniform in the first direction and different from the first transmittance distribution in the region where illumination light is incident. A third transmittance distribution, which is non-uniform in direction and different from the first and second transmittance distributions, is present in the filter unit when the first, second, and third filters are respectively located at reference positions in the first direction. When the first filter is located outside the reference position in the first direction and the second and third filters are respectively located at the reference positions in the first direction, the filter unit has a second composite transmittance distribution. When the third filter and the second filter are located at the reference positions in the first direction, respectively, and the second filter is located outside the reference positions in the first direction, the filter unit has a third composite transmittance distribution. The transmittance of the first composite transmittance distribution is within a specified range. The transmittance of the second composite transmittance distribution increases monotonically from one side of the first direction to the other side, such that it is less than the lower limit of the specified range on one side of the first direction and greater than the upper limit of the specified range on the other side of the first direction; or, it decreases monotonically from one side of the first direction to the other side, such that it is greater than the upper limit of the specified range on one side of the first direction and less than the lower limit of the specified range on the other side of the first direction. The transmittance of the third composite transmittance distribution bulges toward the side with higher transmittance, such that it is less than the lower limit of the specified range on both sides of the first direction; or, it bulges toward the side with lower transmittance, such that it is greater than the upper limit of the specified range on both sides of the first direction.

[0017] According to the 10th disclosure, the illumination unit includes a compound eye lens disposed on the optical axis and the aforementioned filter unit into which the illumination light is incident via the compound eye lens.

[0018] According to the 11th disclosure, the exposure apparatus includes: a first illumination optical system, which is the aforementioned illumination optical system for illuminating a mask; a first projection optical system, which illuminates a substrate with light from the first illumination optical system passing through the mask; a second illumination optical system, which, unlike the first illumination optical system, illuminates the mask; and a second projection optical system, which, unlike the first projection optical system, illuminates the substrate with light from the second illumination optical system passing through the mask, wherein the storage device performs continuous exposure via the first projection optical system and the second projection optical system while moving the substrate along a scanning direction corresponding to the second direction.

[0019] According to the 12th disclosure, the exposure apparatus includes the aforementioned illumination optical system for illuminating a mask and a projection optical system for illuminating a substrate with light from the illumination optical system that has passed through the mask.

[0020] The exposure apparatus scans and exposes a first region of the substrate by means of the projection optical system while moving the substrate along a scanning direction corresponding to the second direction. Then, it scans and exposes a second region of the substrate by means of the projection optical system while moving the substrate along a direction parallel to the scanning direction. This second region of the substrate partially overlaps with the first region and is different from the first region.

[0021] It should be noted that the configuration of the embodiments described below can be appropriately modified, and at least some components can be replaced with other components. Furthermore, the configuration elements that are not particularly limited in their arrangement are not limited to the configuration disclosed in the embodiments, and can be configured in a position that can achieve their function. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the configuration of the exposure apparatus according to an embodiment.

[0024] Figure 2 It is a perspective view schematically showing the configuration of multiple projection optical units.

[0025] Figure 3 (A) is a diagram showing the exposure fields of the multiple projection optical units on the substrate. Figure 3 (B) illustrates scanning the substrate along the X-direction using a substrate stage and passing through... Figure 3 The diagram (A) shows the exposure area formed on the substrate during exposure.

[0026] Figure 4 This is a schematic diagram showing the configuration of the lighting unit according to the embodiment.

[0027] Figure 5 (A) is a schematic diagram showing the configuration of the filter unit. Figure 5 (B) is a schematic top view of the first movable filter, the second movable filter, and the fixed filter.

[0028] Figure 6 (A) is a graph showing the composite transmittance distribution obtained when the first movable filter, the second movable filter, and the fixed filter are respectively located at the reference positions. Figure 6 (B) is a graph showing the composite transmittance distribution obtained when the position of the first movable filter is deviated from the reference position in the Y-axis direction. Figure 6 (C) is a diagram showing the composite transmittance distribution obtained when the position of the second movable filter is deviated from the reference position in the Y-axis direction.

[0029] Figure 7 (A) is a diagram showing the composite transmittance distribution obtained when a fourth filter with a fourth transmittance distribution formed according to a quadratic equation in the Y-axis direction and a fifth filter with a fifth transmittance distribution complementary to the fourth transmittance distribution are located at a reference position. Figure 7 (B) is a graph showing the composite transmittance distribution obtained when the 5th filter is moved Δy (<0) in the Y-axis direction.

[0030] Figure 8 (A) is a graph illustrating the fourth transmittance distribution represented by a function with only fourth-order terms and the fourth transmittance distribution represented by a function with only fifth-order terms. Figure 8 (B) is a diagram illustrating the fourth transmittance distribution represented by a function obtained by combining functions with only 5th degree terms, functions with only 3rd degree terms, and functions with only first degree terms. Detailed Implementation

[0031] based on Figures 1 to 8 (B) describes an exposure apparatus 10 according to one embodiment.

[0032] (Composition of the exposure device)

[0033] Figure 1 This is a diagram that schematically illustrates the configuration of the exposure apparatus 10 according to the embodiment.

[0034] The exposure apparatus 10 is a scanning stepper (scanner) that transfers a pattern formed on the mask MSK onto the substrate P by driving the mask MSK and the glass substrate (hereinafter referred to as the "substrate") P in the same direction and at the same speed relative to the projection optical system PL. The substrate P is, for example, a rectangular glass substrate used in liquid crystal display devices (flat panel displays), with at least one side length or diagonal length of 500 mm or more.

[0035] Hereinafter, the direction in which the mask MSK and substrate P are driven during scanning exposure (scanning direction) will be set as the X-axis direction, the direction in the horizontal plane orthogonal to it will be set as the Y-axis direction, the direction orthogonal to the X-axis and Y-axis will be set as the Z-axis direction, and the rotation (tilt) directions around the X-axis, Y-axis and Z-axis will be set as θx, θy and θz directions respectively.

[0036] The exposure apparatus 10 includes an illumination system IOP, a mask stage MST for holding the mask MSK, a projection optics system PL, a main body 70 supporting these components, a substrate stage PST for holding the substrate P, and a control system for these components. The control system provides unified control over all components of the exposure apparatus 10.

[0037] The main body 70 includes a base (vibration damping platform) 71, columns 72A and 72B, an optical platform 73, a support body 74, and a sliding guide 75. The base (vibration damping platform) 71 is disposed on the floor F to dampen vibrations from the floor F and supports columns 72A and 72B. Columns 72A and 72B each have a frame shape, with column 72A disposed inside column 72B. The optical platform 73 has a flat plate shape and is fixed to the top of column 72A. The support body 74 is supported on the top of column 72B by means of the sliding guide 75. The sliding guide 75 includes a pneumatic ball lifter and a positioning mechanism to position the support body 74 (i.e., the mask stage MST described later) relative to the optical platform 73 at an appropriate position in the X-axis direction.

[0038] The illumination system IOP is positioned above the main body 70. The illumination system IOP illuminates the mask MSK with illumination light IL. The detailed configuration of the illumination system IOP will be described later.

[0039] The mask stage MST is supported on the support body 74. It has a patterned surface on which circuit patterns are formed. Figure 1 The mask MSK (lower surface) is fixed to the mask stage MST, for example, by vacuum adsorption (or electrostatic adsorption). The mask stage MST is driven by a drive system including a linear motor for a specified stroke along the scanning direction (X-axis direction), and is also slightly driven in the non-scanning directions (Y-axis direction and θz direction).

[0040] The position information (including rotation information in the θz direction) of the mask stage MST in the XY plane is measured by an interferometer system. The interferometer system illuminates a measuring beam onto a moving mirror (or a mirror-processed reflective surface (not shown)) located at the end of the mask stage MST, and receives the reflected light from the moving mirror, thereby measuring the position of the mask stage MST. This measurement result is supplied to a control device (not shown), which drives the mask stage MST according to the measurement result of the interferometer system and with the aid of a drive system.

[0041] The projection optical system PL is supported on the optical platform 73 below (on the -Z side) the mask stage MST. The projection optical system PL is configured similarly to, for example, the projection optical system disclosed in U.S. Patent No. 5,729,331, comprising, for example, multiple (e.g., 7) projection optical units 100a-100g (multi-lens projection optical units) arranged in a sawtooth pattern over the projection area of ​​the patterned image of the mask MSK. It should be noted that... Figure 1 In the figure, only four of the seven projection optical units 100a-100g are shown: 100a, 100c, 100e, and 100g.

[0042] Figure 2 This is a perspective view schematically illustrating the configuration of multiple projection optical units 100a-100g. Four projection optical units 100a, 100c, 100e, and 100g are arranged at predetermined intervals along the Y-axis. The remaining three projection optical units 100b, 100d, and 100f are separated from the four units 100a, 100c, 100e, and 100g towards the +X side and are also arranged at predetermined intervals along the Y-axis. The multiple projection optical units 100a-100g each form an upright image, for example, using a telecentric, equal-magnification system.

[0043] Figure 3 (A) is a diagram showing the exposure fields PIa-PIe of the seven projection optical units 100a-100g on substrate P. The exposure fields PIa, PIc, PIe, and PIg of the projection optical units 100a, 100c, 100e, and 100g arranged sequentially in the +Y direction are trapezoids with the shorter side on the +X side and the longer side on the -X side of the two parallel sides in the Y direction. On the other hand, the exposure fields PIb, PId, and PIf of the projection optical units 100b, 100d, and 100f arranged sequentially in the +Y direction are trapezoids with the shorter side on the -X side and the longer side on the +X side of the two parallel sides in the Y direction.

[0044] The exposure field of view Pia, located at the end in the -Y direction, is blocked by a field stop (not shown) in such a way that the end in the -Y direction is parallel to the X direction. Similarly, the exposure field of view Pig, located at the end in the +Y direction, is blocked by a field stop in such a way that the end in the +Y direction is parallel to the X direction.

[0045] Figure 3 (B) shows the substrate P being scanned along the X direction by the substrate stage PST and passed through... Figure 3 (A) shows a diagram of the exposure areas formed on substrate P during exposure of exposure fields PIa-PIg. Exposure areas (scan exposure fields) SIa-SIg are formed on substrate P by scanning exposure, each exposed by an exposure field PIa-PIg. Figure 3In (B), the exposure areas SIa, SIc, SIe, and SIg formed by projection optical units 100a, 100c, 100e, and 100g are represented by single-dotted lines, and the exposure areas SIb, SId, and Sif formed by projection optical units 100b, 100d, and 100f are represented by double-dotted lines.

[0046] The exposure fields PIa-PIg of these exposure regions SIa-SIg are extended in the X direction by scanning exposure in the X direction. The ends of each exposure region SIa-SIg in the Y direction (non-scanning direction) overlap with the ends of the adjacent exposure regions SIa-SIg in the non-scanning direction.

[0047] When the illumination area on the mask MSK is illuminated by illumination light IL from the illumination system IOP, the illumination light IL transmitted from the mask MSK is transmitted through the projection optics system PL to form a projected image (partially upright image) of the circuit pattern of the mask MSK in the illumination area (exposure area (conjugate with the illumination area)) on the substrate P disposed on the image plane side of the projection optics system PL. Here, a resist (sensor) is coated on the surface of the substrate P. The mask stage MST and the substrate stage PST are driven synchronously, that is, the mask MSK is driven in the scanning direction (X-axis direction) relative to the illumination area (illumination light IL), and the substrate P is driven in the same scanning direction relative to the exposure area (illumination light IL), thereby exposing the substrate P and transferring the pattern of the mask MSK onto the substrate P.

[0048] The substrate stage PST is positioned on a base (vibration damping stage) 71 below (on the -Z side) of the projection optical system PL. The substrate P is held on the substrate stage PST by means of a substrate support (not shown).

[0049] The position information (including rotation information (deflection (θz rotation in the θz direction), pitch (θx rotation in the θx direction), and roll (θy rotation in the θy direction))) of the substrate stage PST in the XY plane is measured by an interferometer system. The interferometer system projects a measuring beam from the optical platform 73 onto a moving mirror (or a mirror-processed reflective surface (not shown)) located at the end of the substrate stage PST, and receives the reflected light from the moving mirror, thereby measuring the position of the substrate stage PST. This measurement result is supplied to a control device (not shown), which drives the substrate stage PST according to the measurement result of the interferometer system.

[0050] In the exposure apparatus 10, alignment measurements (e.g., EGA) are performed before exposure, and the results are used to expose the substrate P in the following steps. First, the mask stage MST and the substrate stage PST are synchronously driven along the X-axis direction according to the instructions of the control device. This performs scanning exposure to the first irradiation area on the substrate P. Once the scanning exposure for the first irradiation area is complete, the control device moves the substrate stage PST to a position corresponding to the second irradiation area (stepping). Then, scanning exposure is performed for the second irradiation area. The control device similarly repeats the stepping between irradiation areas of the substrate P and the scanning exposure for irradiation areas, transferring the pattern of the mask MSK to all irradiation areas on the substrate P.

[0051] (Composition of the IOP of the lighting system)

[0052] Next, the configuration of the lighting system IOP in this embodiment will be explained. Figure 4 This is a diagram that roughly illustrates the configuration of an IOP (Integrated Operating System) for a lighting system. (Example) Figure 4 As shown, the lighting system IOP includes a light source unit 20 and multiple lighting optical systems (lighting units) 80a-80g corresponding to the multiple projection optical units 100a-100g of the projection optical system PL. Figure 2 It should be noted that, in Figure 4 The diagram illustrates illumination optical systems 80a and 80b, which are separately configured in the X direction among multiple illumination optical systems 80a-80g. It should be noted that, unless otherwise specified in the following description, illumination optical systems 80a-80g may sometimes be referred to as illumination optical system 80.

[0053] The light source unit 20 includes a light source 21 such as a mercury lamp, an elliptical mirror 22, a curved mirror 23, a relay lens 24, a curved mirror 25, a relay lens 26, and an optical fiber 27. Illumination light supplied from the light source 21 is delivered to the illumination optical system 80a-80g via a light-guiding optical system consisting of the elliptical mirror 22, curved mirror 23, relay lens 24, curved mirror 25, relay lens 26, and optical fiber 27. The optical fiber 27 branches the illumination light incident on one incident side 271 approximately equally, emitting it to seven emission sides 272a-272g (in...). Figure 4 (Only two are shown in the figure). It should be noted that, as the light source 21, a laser light source, a UV (Ultra Violet)-LED (Light Emitting Dioder) light source, etc. can also be used.

[0054] Since the illumination optical systems 80a-80g have the same configuration, the illumination optical system 80a will be described. The illumination optical system 80a includes an input lens 83, a compound eye lens FEL, a condenser lens 84, and a filter unit 85. It should be noted that optical integrators other than compound eye lenses (such as rod integrators) can also be used.

[0055] Illumination light emitted from the emission side 272a of optical fiber 27 is incident on the input lens 83 of illumination optical system 80a.

[0056] A compound eye lens (FEL) is constructed, for example, by arranging multiple lens elements with positive refractive power in a dense, longitudinal and transverse manner, with their optical axes parallel to the reference optical axis AXa. Each lens element constituting the compound eye lens FEL has a rectangular cross-section similar to the shape of the illumination field to be formed on the mask MSK (more specifically, the shape of the exposure area to be formed on the substrate P). It should be noted that, unless otherwise specified in the following description, the reference optical axis AXa and the reference optical axis AXb of the illumination optical system 80b are sometimes referred to as the optical axis AX.

[0057] Therefore, the light beam incident on the compound eye lens FEL is wavefront-splitting by a large number of lens elements, forming a light source image at or near the rear focal plane (emission surface) of each lens element. That is, a substantial surface light source, i.e., a secondary light source, is formed at or near the rear focal plane (emission surface) of the compound eye lens FEL, consisting of a large number of light source images. The light beam from the secondary light source formed at or near the rear focal plane (emission surface) of the compound eye lens FEL is focused by the condenser lens 84 and then overlaps to illuminate the filter unit 85.

[0058] In the exposure apparatus, it is desirable to improve the illuminance uniformity of the illumination light IL (exposure light) that illuminates the mask MSK. Furthermore, after scanning exposure of the first irradiated area on the substrate P ends, the substrate stage PST is moved (stepped) to a position corresponding to the second irradiated area (the first and second irradiated areas are arranged along the non-scanning direction). Then, in the case where scanning exposure of the second irradiated area is performed with a portion overlapping the first irradiated area (in the case of image compositing), by driving the light shield to overlap with the opening of the field stop (trapezoidal) included in the projection optical unit that exposes the overlapping portion of the first and second irradiated areas (the connecting portion in the image compositing), the size of the exposure field of view (trapezoidal) of the projection optical unit exposing the connecting portion in the image compositing can be changed, making the position of the connecting portion in the image compositing variable. At this time, it is preferable to suppress the non-uniformity of the illuminance distribution in the X-axis direction (scanning direction) in advance. It should be noted that the field stop can be positioned approximately conjugately with respect to the mask MSK and the substrate P.

[0059] Therefore, the exposure apparatus 10 of this embodiment includes a filter unit 85, which has the function of making the illuminance distribution of the illumination light IL that illuminates the mask MSK uniform. The illumination light IL with uniform illuminance distribution is used by the filter unit 85 to illuminate the mask MSK.

[0060] Next, the configuration of the filter unit 85 will be explained. Figure 5 (A) is a schematic diagram showing the configuration of the filter unit 85.

[0061] The filter unit 85 includes a first movable filter 85a (first filter), a second movable filter 85b (third filter), and a fixed filter 85c (second filter) arranged along the optical axis AX (corresponding to the Z-axis direction).

[0062] The first movable filter 85a, the second movable filter 85b, and the fixed filter 85c are each in the form of a parallel planar plate made of an optical material such as quartz or i-line glass, and their thickness is approximately fixed. A dense pattern of light-shielding dots composed of chromium, chromium oxide, etc., is formed on the optical surface of each of the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c.

[0063] The first movable filter 85a, the second movable filter 85b, and the fixed filter 85c each have a transmittance distribution with different transmittance corresponding to the incident position of light (more specifically, the position in the X-axis direction and the Y-axis direction).

[0064] Figure 5 (B) is a schematic top view of the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c. The first movable filter 85a, the second movable filter 85b, and the fixed filter 85c have a circular shape centered on, for example, the optical axis AX.

[0065] In this embodiment, the first movable filter 85a is configured to maintain an orientation in which its incident surface is orthogonal to the optical axis AX, and is movable along both the X-axis and Y-axis directions. The second movable filter 85b is configured to maintain an orientation in which its incident surface is orthogonal to the optical axis AX, and is movable along the Y-axis direction. It should be noted that the second movable filter 85b can also be configured to be movable in the X-axis direction.

[0066] Therefore, in this embodiment, the relative position of the first movable filter 85a and the fixed filter 85c can be changed in both the X-axis and Y-axis directions. Furthermore, the relative position of the second movable filter 85b and the fixed filter 85c can be changed in the Y-axis direction. It should be noted that the position where the centers of the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c are aligned with the optical axis AX is referred to as the reference position.

[0067] Next, the transmittance distribution of the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c will be explained.

[0068] like Figure 5 As shown in (B), when an XY coordinate system (orthogonal coordinate system) with the center of the circular first movable filter 85a (which is aligned with the optical axis AX) as the origin is defined, the first movable filter 85a has a first transmittance distribution T1 (x, y) represented by local coordinates (x, y).

[0069] More specifically, the first transmittance distribution T1(x, y) is formed in the Y-axis direction according to a function Ty1(y) represented by an nth-degree equation (n is a natural number greater than 2) with the y-coordinate as the variable.

[0070] Furthermore, the first transmittance distribution T1(x, y) in the X-axis direction is formed according to a function Tx1(x) represented by a k-th degree equation (k is a natural number greater than 2) with the x-coordinate as the variable.

[0071] The second movable filter 85b has a second transmittance distribution T2(x,y) represented by local coordinates (x,y). More specifically, the second transmittance distribution T2(x,y) is formed in the Y-axis direction according to a function Ty2(y) represented by an m-th degree equation (m is a natural number greater than 2) with the y-coordinate as the variable.

[0072] Furthermore, in this embodiment, the second transmittance distribution T2(x, y) has the same transmittance (e.g., 100%) in the X-axis direction. That is, the second transmittance distribution T2(x, y) is formed in the X-axis direction according to the function Tx2(x) = const (const is a constant).

[0073] The fixed filter 85c has a third transmittance distribution T3(x,y) that is complementary to the first transmittance distribution T1(x,y) and the second transmittance distribution T2(x,y). Here, complementary to the first transmittance distribution T1(x,y) and the second transmittance distribution T2(x,y) means that the product of the first transmittance distribution T1(x,y) and the third transmittance distribution T3(x,y) is approximately fixed (approximately flat), and the product of the second transmittance distribution T2(x,y) and the third transmittance distribution T3(x,y) is approximately fixed (approximately flat).

[0074] The third transmittance distribution T3(x, y) is formed along the Y-axis by a function Ty3(y) that is complementary to both functions Ty1(y) and Ty2(y). Here, complementarity with functions Ty1(y) and Ty2(y) means that the product of functions Ty1(y) and Ty3(y) is approximately constant (approximately flat), and the product of functions Ty2(y) and Ty3(y) is also approximately constant. Furthermore, the third transmittance distribution T3(x, y) is formed along the X-axis by a function Tx3(x) that is complementary to function Tx1(x). Here, complementarity with function Tx1(x) means that the product of functions Tx1(x) and Ty3(y) is approximately constant.

[0075] It should be noted that, in the following explanation, the function Ty1(y) is sometimes denoted as the first transmittance distribution Ty1(y) in the Y-axis direction, the function Ty2(y) is denoted as the second transmittance distribution Ty2(y) in the Y-axis direction, and the function Tx1(x) is denoted as the first transmittance distribution Tx1(x) in the X-axis direction. Additionally, the function Ty3(y) is sometimes denoted as the third transmittance distribution Ty3(y) in the Y-axis direction.

[0076] Light incident on filter unit 85 passes sequentially through a first movable filter 85a, a second movable filter 85b, and a fixed filter 85c. At this time, the illuminance distribution of the light incident on filter unit 85 corresponds to the composite transmittance distribution Ts obtained by combining the first transmittance distribution T1(x, y), the second transmittance distribution T2(x, y), and the third transmittance distribution T3(x, y). cmb (x, y) is used for correction. It should be noted that in the following explanation, the composite transmittance distribution along the Y-axis is expressed in terms of T. cmb (y) represents.

[0077] Here, the composite transmittance distribution is explained. It should be noted that, for ease of explanation and understanding, the following explanation focuses on the correction of the illuminance distribution along the Y-axis, while the correction for the illuminance distribution along the X-axis is the same.

[0078] Figure 6(A) is a diagram showing the composite transmittance distribution along the Y-axis obtained when the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c are respectively located at reference positions. Figure 6 (B) is a graph showing the composite transmittance distribution obtained when the position of the first movable filter 85a is deviated from the reference position in the Y-axis direction. Figure 6 (C) is a graph showing the composite transmittance distribution obtained when the position of the second movable filter 85b is deviated from the reference position in the Y-axis direction. It should be noted that... Figure 6 (A) to Figure 6 In (C), the function Ty1(y) representing the first transmittance distribution along the Y-axis is derived from Ty1(y) = αy 2 The quadratic equation expressed in terms of +β (α and β are arbitrary coefficients) represents the function Ty2(y) representing the second transmittance distribution along the Y-axis, which is derived from Ty2(y) = γy. 3 The cubic equation represented by +ωy + λ (γ, ω, and λ are arbitrary coefficients).

[0079] like Figure 6 As shown in (A), the third transmittance distribution Ty3(y) in the Y-axis direction is complementary to the first transmittance distribution Ty1(y) and the second transmittance distribution Ty2(y) in the Y-axis direction. Therefore, the composite transmittance distribution Ty in the Y-axis direction obtained when the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c are respectively located at the reference position is... cmb (y) is roughly fixed (roughly flat) in the Y-axis direction.

[0080] like Figure 6 As shown in (B), the composite transmittance distribution Ty in the Y-axis direction is obtained when the position of the first movable filter 85a is deviated from the reference position in the Y-axis direction. cmb (y) becomes a distribution represented by a linear equation of degree one lower than the first transmittance distribution Ty1(y) (degree 2). Therefore, when the illuminance distribution is skewed along the Y-axis, if the first transmittance distribution along the Y-axis is used, it is represented by Ty1(y) = αy 2 The first movable filter 85a, represented by +β, can correct the illuminance distribution that is tilted in the Y-axis direction. This correction is called tilt correction.

[0081] In addition, such as Figure 6 As shown in (C), the composite transmittance distribution Ty in the Y-axis direction is obtained when the position of the second movable filter 85b is deviated from the reference position in the Y-axis direction. cmb(y) becomes a distribution represented by a quadratic equation of degree one lower than the third degree (3rd degree) of the second transmittance distribution Ty2(y) in the Y-axis direction. Therefore, when the illuminance distribution is curved in the Y-axis direction, if the second transmittance distribution in the Y-axis direction is used, it is represented by Ty2(y) = γy. 3 The second movable filter 85b, represented by +ωy+λ, can correct for the illuminance distribution that is curved in the Y-axis direction. This correction is called curvature correction.

[0082] Here, the combined transmittance distribution Ty in the Y-axis direction is as follows: (The first movable filter 85a is deviated from the reference position in the Y-axis direction, and the second movable filter 85b is deviated from the reference position.) cmb The principle that the order of (y) is one order lower than that of the first transmittance distribution Ty1(y) and the second transmittance distribution Ty2(y) in the Y-axis direction is explained.

[0083] Figure 7 (A) is a diagram showing the composite transmittance distribution obtained when a fourth filter having a fourth transmittance distribution Ty4 formed according to a quadratic equation in the Y-axis direction and a fifth filter having a fifth transmittance distribution Ty5 complementary to the fourth transmittance distribution Ty4 are located at a reference position. Figure 7 (B) is a graph showing the composite transmittance distribution obtained when the 5th filter is moved Δy (<0) in the Y-axis direction.

[0084] Since the fourth transmittance distribution Ty4 and the fifth transmittance distribution Ty5 are complementary, they are represented as follows:

[0085]

Mathematical Formula 1

[0086] .

[0087] In this case, with the 4th and 5th filters located at the reference positions, the combined transmittance distribution is as follows:

[0088]

Mathematical Formula 2

[0089] ,

[0090] Because f(y) 2 <<T ave 2 Therefore, it became

[0091]

Mathematical Expression 3

[0092] ,

[0093] like Figure 7As shown in (A), the synthetic transmittance distribution is roughly fixed (roughly flat).

[0094] On the other hand, when the fifth filter is deviated from Δy, the fourth transmittance distribution Ty4 and the fifth transmittance distribution Ty5 are respectively expressed as follows:

[0095]

Mathematical Expression 4

[0096]

[0097]

Mathematical Expression 5

[0098] .

[0099] In this case, the combined transmittance distribution of the fourth and fifth transmittance distributions becomes

[0100]

Mathematical Expression 6

[0101] ,

[0102] It can be seen that it is expressed by a formula that is one order smaller than the fourth transmittance distribution.

[0103] Based on the above, when the fourth transmittance distribution is formed according to a function represented by an equation of degree j (j is a natural number of degree j or higher), a composite transmittance distribution represented by an equation of degree j-1 can be obtained by combining the fourth filter with a fifth filter having a fifth transmittance distribution that is complementary to the fourth transmittance distribution.

[0104] That is, if the target synthetic transmittance distribution is represented by a j-1 degree equation, then the fourth transmittance distribution of the fourth filter can be represented by a j-1 degree equation. However, the larger j is (the higher the degree of the function representing the fourth transmittance distribution), the larger the transmittance width (the difference between the minimum and maximum transmittance). Therefore, it is preferable that the fourth transmittance distribution in the Y-axis direction has terms of degree j-1 or lower. This point will be explained.

[0105] Figure 8 (A) is an example of a function f1(y) = ay with only 4th degree terms. 4 The fourth transmittance distribution, represented by (a is an arbitrary coefficient), and the function f2(y) = by, which has only 5th degree terms. 5的（ The graph representing the fourth transmittance distribution (where b is an arbitrary coefficient). For example... Figure 8 As shown in (A), by the function f2(y) = by 5 The transmittance width W2 of the fourth transmittance distribution is greater than that given by the function f1(y) = ay 4The transmittance width W1 represents the fourth transmittance distribution. As such, the higher the degree of the function representing the fourth transmittance distribution, the larger the transmittance width. If the transmittance width increases, the transmittance will be too low when the fourth filter deviates from the reference position, resulting in reduced illumination.

[0106] The inventors of this application have discovered that in the fourth transmittance distribution represented by a function of the j-th degree equation, the transmittance width can be reduced by including terms of degree j-1 or lower in the function. Figure 8 (B) shows the result of f2(y) = by 5 (where b is any coefficient), the function f3 has (y) = cy 3 (where c is any coefficient) and the function f4(y) = py (where p is any coefficient) combine to obtain the function f5(y) = f2(y) + f3(y) + f4(y) = by 5 +cy 3 The diagram showing the fourth transmittance distribution formed by +py.

[0107] like Figure 8 As shown in (B), it can be seen that the transmittance width W3 of the fourth transmittance distribution formed according to function f5(y) is smaller than the transmittance width W2 of the fourth transmittance distribution formed according to function f2(y). In this way, the transmittance width can be reduced by including terms of degree j-1 or lower in the function represented by the j-th degree equation representing the transmittance distribution.

[0108] Therefore, in this embodiment, the second transmittance distribution Ty2(y) in the Y-axis direction of the second movable filter 85b becomes a cubic equation (γy) containing a first-order term (ωy). 3 By constructing it in this way, it is possible to reduce the transmittance width and suppress the decrease in transmittance.

[0109] In both the case of using an existing filter unit and the case of using the filter unit 85 of this embodiment, the illuminance in the illumination area formed by multiple illumination units is measured, and the illuminance uniformity is investigated.

[0110] In an existing filter unit, multiple filters with dense patterns of light-blocking dots are prepared. Each filter has a transmittance distribution that varies depending on the incident position of the light (more specifically, the positions in the X-axis and Y-axis directions), forming a predetermined transmittance distribution corresponding to tilt correction and bending correction. In this filter unit, by selecting a filter corresponding to the desired illuminance distribution and rotating the filter, the non-uniformity (illuminance deviation) of the illuminance distribution in the Y-axis direction, obtained by averaging the cumulative illuminance in the X-axis direction (called scan averaging), is corrected.

[0111] Using the illuminance distribution of the entire illumination area comprising multiple illumination optical systems, the illuminance distribution along the Y-axis after scanning averaging, and the illuminance change rate of the illuminance distribution along the Y-axis as indicators, this study investigates the extent to which illuminance deviations can be corrected using existing methods and the method of this embodiment, based on multiple illuminance deviation data reflecting the manufacturing accuracy of the exposure apparatus.

[0112] The evaluation was conducted under conditions where a filter unit was equipped with existing methods for tilt correction and bending correction, respectively. The rotation angle was calculated and corrections were applied for the illuminance deviation of each data point, and the above-mentioned index values ​​were calculated.

[0113] In this embodiment, the movable filter is evaluated under the condition of tilt correction in the X-axis and Y-axis directions and bending correction in the Y-axis direction. The mobility in the X-axis and Y-axis directions is calculated and corrected for the illuminance deviation of each data, and the above-mentioned index value is calculated.

[0114] By comparing the average value of the survey data, in any of the above indicators, the method of this embodiment calculates that the illuminance deviation is suppressed to less than approximately 50% compared with the existing method.

[0115] In particular, existing methods, which aim to correct illuminance deviation after scanning averaging, offer limited correction for illuminance deviation across the entire illumination area. However, in the method of this embodiment, by appropriately calculating the mobility of the movable filter, the degree of freedom to correct illuminance deviation across the entire illumination area is ensured. Compared to existing methods, illuminance deviation can be suppressed to approximately 1 / 3 or less based on the average value of the data. Thus, the filter unit 85 of this embodiment exhibits a significant improvement in illuminance deviation compared to existing filter units.

[0116] As shown above, it has been confirmed that the uniformity of illumination is improved by using the filter unit 85 of this embodiment.

[0117] As detailed above, according to this embodiment, the filter unit 85 includes a plurality of filters disposed on the optical axis AX of the illumination optical system 80 illuminating the mask MSK. The plurality of filters includes a first movable filter 85a having a first transmittance distribution T1(x, y) and a fixed filter 85c having a third transmittance distribution T3(x, y). The first transmittance distribution T1(x, y) is formed in the Y-axis direction of the XY coordinate system in a plane orthogonal to the optical axis AX of the illumination optical system 80 according to a function Ty1(y) expressed by an nth-degree equation (n is a natural number of 2 or more) with coordinates in the Y-axis direction as variables. The third transmittance distribution T3(x, y) is at least complementary to the first transmittance distribution Ty1(y) in the Y-axis direction. The relative position of the first movable filter 85a and the fixed filter 85c can be changed at least in the Y-axis direction.

[0118] Therefore, if used Figure 7 (A) and Figure 7 As explained in (B), by moving the first movable filter 85a from the reference position, a composite transmittance distribution expressed by an n-1 degree equation can be generated, and the illuminance distribution of the illumination light IL can be corrected by the composite transmittance distribution expressed by the n-1 degree equation.

[0119] Furthermore, in this embodiment, the plurality of filters includes a second movable filter 85b having a second transmittance distribution T2(x, y). The second transmittance distribution is formed in the Y-axis direction according to a function Ty2(y) expressed by an m-th degree equation (m is a natural number greater than 2) with coordinates in the Y-axis direction as variables. The third transmittance distribution T3(x, y) of the fixed filter 85c is complementary to the first transmittance distribution Ty1(y) and the second transmittance distribution Ty2(y) in the Y-axis direction. The relative position of the fixed filter 85c and the second movable filter 85b can be changed in the Y-axis direction.

[0120] Therefore, by moving the second movable filter 85bΔy in the Y-axis direction, a composite transmittance distribution expressed by an m-1 degree equation can be generated. Thus, the illuminance distribution of the illumination light IL can be corrected using the composite transmittance distribution expressed by the m-1 degree equation.

[0121] Furthermore, in this embodiment, the function Ty2(y) has terms of degree m-1 or lower. Therefore, if using... Figure 8 (A) and Figure 8 As explained in (B), the transmittance width, which is the difference between the maximum and minimum transmittance of the second movable filter 85b, can be reduced. Therefore, the reduction in illuminance of the illumination light IL caused by the filter unit 85 can be suppressed.

[0122] Furthermore, in this embodiment, the degree of Ty2(y), representing the second transmittance distribution in the Y-axis direction, is greater than the degree of Ty1(y), representing the first transmittance distribution in the Y-axis direction, which is greater than the degree of Ty1(y). As a result, the first movable filter 85a and the second movable filter 85b can be assigned different correction functions (tilt correction, bending correction).

[0123] Furthermore, in this embodiment, the first transmittance distribution is formed in the X-axis direction according to a function Tx1(x) represented by a k-th degree equation (k is a natural number greater than 2) with the coordinates in the X-axis direction as variables, the third transmittance distribution T3(x, y) is complementary to the first transmittance distribution Tx1(x) in the X-axis direction, and the relative positions of the first movable filter 85a and the fixed filter 85c can be changed in the Y-axis direction and the X-axis direction.

[0124] Therefore, by moving the first movable filter 85a from the reference position in the X-axis direction, a composite transmittance distribution represented by a k-1 degree equation can be generated in the X-axis direction, and the illuminance distribution in the X-axis direction of the illumination light IL can be corrected by the composite transmittance distribution represented by the k-1 degree equation.

[0125] Furthermore, in this embodiment, the function Tx1(x) representing the first transmittance distribution along the X-axis direction contains terms of degree k-1 or lower. Therefore, if using... Figure 8 (A) and Figure 8 As explained in (B), the transmittance width, which is the difference between the maximum and minimum transmittance of the first movable filter 85a, can be reduced. Therefore, the reduction in illuminance of the illumination light IL caused by the filter unit 85 can be suppressed.

[0126] The correction of the illuminance distribution of the illumination light IL by the filter unit 85 is performed at predetermined times when the exposure apparatus 10 is set up, when the exposure apparatus 10 is maintained, and when the exposure apparatus 10 is in use. In this case, the illuminance distribution of the illumination light IL is measured, and based on the measurement result, the positions of the first movable filter 85a and the second movable filter 85b that can make the illuminance distribution of the illumination light IL uniform are calculated. The first movable filter 85a and the second movable filter 85b are then moved to the positions. The positions of the first movable filter 85a and the second movable filter 85b can be moved manually or by using an actuator such as a motor. Thus, optimal adjustments can be made for multiple illumination optical systems mounted on the exposure apparatus that have different σ values. In addition, for changes in illuminance deviation (non-uniformity of illuminance distribution) corresponding to the usage conditions of the exposure apparatus, the position of the movable filter can be calculated by measuring the illuminance distribution at predetermined times and optimal adjustments can be made. Furthermore, when the exposure area on the substrate P is deformed to correspond to the pattern shape of various masks, the illuminance deviation of the entire illumination area can be suppressed, thereby effectively suppressing the exposure deviation, including the connection area of ​​multiple lenses.

[0127] It should be noted that, in the above embodiments, the first movable filter 85a can have the function of correcting the illuminance distribution in the X-axis direction, and the second movable filter 85b can also have the function of correcting the illuminance distribution in the X-axis direction. Alternatively, a filter different from the first movable filter 85a and the second movable filter 85b can also have the function of correcting the illuminance distribution in the X-axis direction.

[0128] Furthermore, in the above embodiment, the fixed filter 85c has a third transmittance distribution that is complementary to the first transmittance distribution of the first movable filter 85a and the second transmittance distribution of the second movable filter 85b in the Y-axis direction, and complementary to the first transmittance distribution of the first movable filter 85a in the X-axis direction. However, filters having transmittance distributions complementary to the first transmittance distribution and filters having transmittance distributions complementary to the second transmittance distribution can also be configured separately. Alternatively, filters having transmittance distributions complementary to the first transmittance distribution in the Y-axis direction and filters having transmittance distributions complementary to the first transmittance distribution in the X-axis direction can also be configured separately. Additionally, the third transmittance distribution of the fixed filter 85c may not be complementary to the first transmittance distribution of the first movable filter 85a and the second transmittance distribution of the second movable filter 85b in the Y-axis direction, or it may not be complementary to the first transmittance distribution of the first movable filter 85a in the X-axis direction.

[0129] In addition, in the above embodiment, the transmittance distribution in the X-axis direction of the second movable filter 85b is fixed, but the transmittance distribution in the X-axis direction can also be formed according to a function represented by a j-th degree equation (j is a natural number of degree 2 or higher) with the coordinates in the X-axis direction as variables.

[0130] Furthermore, in the above embodiment, the filter unit 85, which constitutes the elements of the illumination optical system 80, is positioned as close as possible to the mask MSK, but this is not a limitation. The filter unit 85 can be positioned at an appropriate location in the optical path of the illumination optical system 80. Additionally, spatial light modulation elements such as digital micromirror devices (DMDs), which regularly arrange multiple micromirrors with minute displacements, can be used instead of the mask MSK and can be positioned appropriately.

[0131] In addition, in the above embodiment, the fixed filter 85c does not move (fixed) in the X-axis direction and the Y-axis direction, but the fixed filter 85c can also be moved in at least one of the X-axis direction and the Y-axis direction.

[0132] Furthermore, according to the above embodiment, the filter unit 85 includes a plurality of filters disposed on the optical axis AX of the illumination optical system 80. The plurality of filters includes a first movable filter 85a, a second movable filter 85b, and a fixed filter 85c. The first movable filter 85a has a first transmittance distribution that is non-uniform in the Y-axis direction intersecting the optical axis AX in the region where the illumination light IL is incident. The second movable filter 85b has a second transmittance distribution that is non-uniform in the Y-axis direction and different from the first transmittance distribution in the region where the illumination light IL is incident. The fixed filter 85c has a third transmittance distribution that is non-uniform in the Y-axis direction and different from both the first and second transmittance distributions in the region where the illumination light IL is incident. When the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c are respectively located at a reference position in the Y-axis direction, the filter unit 85 has a first composite transmittance distribution. When the first movable filter 85a is located outside the reference position in the Y-axis direction and the second movable filter 85b and the fixed filter 85c are respectively located at the reference position in the Y-axis direction, the filter unit 85 has a second composite transmittance distribution. When the first movable filter 85a and the fixed filter 85c are located at the reference position in the Y-axis direction and the second movable filter 85b is located outside the reference position in the Y-axis direction, the filter unit 85 has a third composite transmittance distribution. The transmittance of the first composite transmittance distribution is within a specified range. The transmittance of the second composite transmittance distribution increases monotonically from one side of the Y-axis direction to the other, such that it is less than the lower limit of the specified range on one side of the Y-axis direction and greater than the upper limit of the specified range on the other side of the Y-axis direction; or, it decreases monotonically from one side of the Y-axis direction to the other, such that it is greater than the upper limit of the specified range on one side of the Y-axis direction and less than the lower limit of the specified range on the other side of the Y-axis direction. The third composite transmittance distribution bulges towards the side with higher transmittance, such that its transmittance is less than the lower limit of the specified range on both sides of the Y-axis direction; or, it bulges towards the side with lower transmittance, such that its transmittance is greater than the upper limit of the specified range on both sides of the Y-axis direction.

[0133] Furthermore, in the above embodiment, the first movable filter 85a has a first transmittance distribution that is non-uniform in the Y-axis direction along the X-axis direction orthogonal to the Y-axis direction in the region where the illumination light IL is incident; the second movable filter 85b has a second transmittance distribution that is non-uniform in the Y-axis direction along the X-axis direction in the region where the illumination light IL is incident; and the fixed filter 85c has a third transmittance distribution that is non-uniform in the Y-axis direction along the X-axis direction in the region where the illumination light IL is incident.

[0134] In addition, in the above embodiments, the first synthetic transmittance distribution is approximately fixed, the second synthetic transmittance distribution is tilted, and the third synthetic transmittance distribution is curved.

[0135] Furthermore, in the above embodiment, the reference positions of the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c are respectively the positions where the center of the first movable filter 85a, the center of the second movable filter 85b, and the center of the fixed filter 85c are aligned with the optical axis AX in the Y-axis direction.

[0136] In addition, in the above embodiment, the first movable filter 85a is movable in the Y-axis direction, the second movable filter 85b is movable in the Y-axis direction, and the fixed filter 85c is fixed at the reference position in the Y-axis direction.

[0137] Furthermore, in the above embodiment, the illumination light IL incident area of ​​each of the first movable filter 85a, the second movable filter 85b, and the fixed filter 85c is rectangular.

[0138] Furthermore, in the above embodiment, the difference between the upper and lower limits of the specified range is less than the difference between the maximum and minimum transmittance of the first transmittance distribution, less than the difference between the maximum and minimum transmittance of the second transmittance distribution, and less than the difference between the maximum and minimum transmittance of the third transmittance distribution.

[0139] Furthermore, in the above embodiments, the first transmittance distribution protrudes towards the side with high transmittance or towards the side with low transmittance, the second transmittance distribution includes a first region protruding towards the side with high transmittance and a second region protruding towards the side with low transmittance, and the third transmittance distribution includes a region protruding towards the side with low transmittance and corresponding to the first region, and a region protruding towards the side with high transmittance and corresponding to the second region.

[0140] In addition, in the above embodiment, the filter unit 85 is configured such that light from the filter unit 85 is incident on the mask MSK without passing through a lens.

[0141] In addition, according to the above embodiment, the illumination optical system 80 includes a compound eye lens FEL disposed on the optical axis AX and a filter unit 85 through which the illumination light IL is incident via the compound eye lens FEL.

[0142] Furthermore, according to the above embodiment, the exposure apparatus 10 includes an illumination optical system 80a that illuminates a mask MSK, a projection optical unit 100a that illuminates a substrate with light from the illumination optical system 80a that has passed through the mask MSK, an illumination optical system 80b that illuminates the mask MSK and is different from the illumination optical system 80a, and a projection optical unit 100b that illuminates a substrate P with light from the illumination optical system 80b that has passed through the mask MSK and is different from the projection optical unit 100a. The exposure apparatus 10 moves the substrate P in a scanning direction corresponding to the X-axis direction while continuously exposing it through the projection optical unit 100a and the projection optical unit 100b.

[0143] It should be noted that, in the above embodiments, the exposure apparatus 10 may also include an illumination optical system 80 for illuminating the mask MSK and a projection optical system PL for illuminating the substrate P with light from the illumination optical system 80 that has passed through the mask MSK. While moving the substrate P along a scanning direction corresponding to the X-axis direction, the projection optical system PL scans and exposes a first region of the substrate P. While moving the substrate P along a direction parallel to the scanning direction, the projection optical system PL scans and exposes a second region of the substrate P that partially overlaps with the first region and is different from the first region.

[0144] The above-described embodiments are preferred embodiments of the present invention. However, they are not limited thereto, and various modifications can be implemented without departing from the spirit of the present invention.

[0145] Explanation of reference numerals in the attached figures

[0146] 10 Exposure Devices

[0147] 80a-80g Illumination Optical System

[0148] 85 filter unit

[0149] 85a First Movable Filter

[0150] 85b Second Movable Filter

[0151] 85c fixed filter

[0152] 100 projection optical units

[0153] 21 light sources

[0154] MSK mask

[0155] PL projection optical system.

Claims

1. A filter unit comprising a plurality of filters disposed on the optical axis of an illumination optical system illuminating an illuminated surface, wherein, The plurality of filters includes: A first filter having a first transmittance distribution; and A second filter with a second transmittance distribution. The first transmittance distribution lies in the first direction of an orthogonal coordinate system within a plane orthogonal to the optical axis of the illumination optical system, and is formed according to a first function expressed by an nth-degree equation with the coordinates in the first direction as variables, where n is a natural number greater than 2. The relative positions of the first filter and the second filter can be changed at least in the first direction.

2. The filter unit according to claim 1, wherein, The second transmittance distribution is at least complementary to the first transmittance distribution in the first direction.

3. The filter unit according to claim 2, wherein, The first function has terms of degree n-1 or lower.

4. The filter unit according to claim 1, wherein, The plurality of filters includes a third filter having a third transmittance distribution. The third transmittance distribution in the first direction is formed according to a second function expressed by an m-th degree equation with the coordinates in the first direction as variables, where m is a natural number greater than 2. The second transmittance distribution is complementary to the first transmittance distribution and the third transmittance distribution in the first direction. The relative positions of the second filter and the third filter can be changed in the first direction.

5. The filter unit according to claim 4, wherein, The second function has terms of degree m-1 or lower.

6. The filter unit according to claim 4, wherein, m is greater than n.

7. The filter unit according to claim 4, wherein, The first transmittance distribution is formed in the orthogonal coordinate system along a second direction orthogonal to the first direction, according to a third function expressed by a k-th degree equation with the coordinates along the second direction as variables, where k is a natural number greater than 2. The second transmittance distribution is complementary to the first transmittance distribution in the second direction. The relative positions of the first filter and the second filter can be changed in the first direction and the second direction.

8. The filter unit according to claim 7, wherein, The third function contains terms of degree k-1 or lower.

9. The filter unit according to claim 1, wherein, The plurality of filters includes: A third filter having a third transmittance distribution; and The fourth filter has a fourth transmittance distribution. The third transmittance distribution in the first direction is formed according to a second function expressed by an m-th degree equation with the coordinates in the first direction as variables, where m is a natural number greater than 2. The fourth transmittance distribution is complementary to the third transmittance distribution in the first direction. The relative positions of the third filter and the fourth filter can be changed at least in the first direction.

10. The filter unit according to claim 1, wherein, The plurality of filters includes a third filter having a third transmittance distribution. The third transmittance distribution is formed in the second direction of the orthogonal coordinate system, orthogonal to the first direction, according to a second function expressed by a k-th degree equation with the coordinates in the second direction as variables, where k is a natural number greater than 2. The second transmittance distribution is complementary to the third transmittance distribution in the second direction. The relative positions of the second filter and the third filter can be changed in the second direction.

11. The filter unit according to claim 1, wherein, The plurality of filters includes: A third filter having a third transmittance distribution; and The fourth filter has a fourth transmittance distribution. The third transmittance distribution is formed in the second direction of the orthogonal coordinate system, orthogonal to the first direction, according to a second function expressed by a k-th degree equation with the coordinates in the second direction as variables, where k is a natural number greater than 2. The fourth transmittance distribution is complementary to the third transmittance distribution in the second direction. The relative positions of the third filter and the fourth filter can be changed in the second direction.

12. A lighting unit comprising: An optical integrator for light emitted from a light source to enter; as well as The filter unit according to any one of claims 1 to 11, The light emitted from the optical integrator is incident on the filter unit.

13. An exposure apparatus comprising: The lighting unit as described in claims 12; as well as Multiple projection optical units, corresponding to the multiple illumination units, project the pattern image of the mask illuminated by the multiple illumination units onto a photosensitive substrate. The plurality of projection optical units includes a first projection optical unit and a second projection optical unit. The exposure area of ​​the first projection optical unit partially overlaps with the exposure area of ​​the second projection optical unit.

14. The exposure apparatus according to claim 13, wherein, The length of at least one side or the diagonal length of the photosensitive substrate is 500 mm or more.

15. An exposure method using the exposure apparatus of claim 13, the exposure method comprising: The mask is illuminated using the plurality of lighting units; as well as The pattern image of the mask is projected onto the photosensitive substrate using the projection optics unit.

16. A filter unit comprising a plurality of filters disposed on the optical axis of an optical system, wherein, The plurality of filters includes: A first filter having a first transmittance distribution; and A second filter with a second transmittance distribution. The first transmittance distribution is non-uniform in the first direction of an orthogonal coordinate system within a plane orthogonal to the optical axis of the optical system. The second transmittance distribution is not uniform in the first direction. The relative positions of the first filter and the second filter can be changed at least in the first direction.

17. The filter unit according to claim 16, wherein, With the plurality of filters located at a reference position, the combined transmittance distribution of the plurality of filters is approximately fixed in the first direction.

18. The filter unit according to claim 16, wherein, The plurality of filters includes a third filter having a third transmittance distribution. The relative positions of the third filter and the second filter can be changed at least in the first direction. The first transmittance distribution follows a first function expressed by an nth-degree equation with coordinates in the first direction as variables, where n is a natural number greater than 2. The third transmittance distribution follows a third function expressed by a k-th degree equation with the coordinates in the first direction as variables, where k is a natural number greater than or equal to 3. The second transmittance distribution follows a second function represented by an m-th degree equation with the coordinates in the first direction as variables, where m is a natural number greater than or equal to n+k.

19. The filter unit according to claim 18, wherein, The third function has terms of degree m-1 or lower.

20. A lighting unit comprising: An optical integrator for light emitted from a light source to enter; as well as A filter unit according to any one of claims 16 to 19, which provides incident light emitted from the optical integrator.

21. An exposure apparatus comprising: The lighting unit as described in claims 20; as well as Multiple projection optical units corresponding to the multiple lighting units, The plurality of projection optical units includes a first projection optical unit and a second projection optical unit. The exposure area of ​​the first projection optical unit partially overlaps with the exposure area of ​​the second projection optical unit.

22. The exposure apparatus according to claim 21, wherein, The length of at least one side or the diagonal length of the photosensitive substrate projected by the plurality of projection optical units is 500 mm or more.

23. An exposure method using the exposure apparatus of claim 21, comprising: The mask is illuminated using the plurality of lighting units; as well as The pattern image of the mask is projected onto the photosensitive substrate using the plurality of projection optical units.

24. A filter unit comprising a plurality of filters disposed on the optical axis of an optical system, wherein, The plurality of filters includes a first filter, a second filter, and a third filter. The first filter has a non-uniform first transmittance distribution in the region where the illumination light is incident, in a first direction intersecting the optical axis. The second filter has a second transmittance distribution that is non-uniform in the first direction and different from the first transmittance distribution in the region where the illumination light is incident. The third filter has a third transmittance distribution in the region where the illumination light is incident, which is non-uniform in the first direction and different from the first and second transmittance distributions. When the first filter, the second filter, and the third filter are respectively located at reference positions in the first direction, the filter unit has a first composite transmittance distribution. When the first filter is located outside the reference position in the first direction, and the second and third filters are respectively located at the reference positions in the first direction, the filter unit has a second composite transmittance distribution. When the first filter and the third filter are respectively located at the reference position in the first direction, and the second filter is located outside the reference position in the first direction, the filter unit has a third composite transmittance distribution. The transmittance of the first synthetic transmittance distribution is within the specified range. The transmittance of the second synthetic transmittance distribution increases monotonically from one side of the first direction to the other, such that it is less than the lower limit of the predetermined range on one side of the first direction and greater than the upper limit of the predetermined range on the other side of the first direction; or, it decreases monotonically from one side of the first direction to the other, such that it is greater than the upper limit of the predetermined range on one side of the first direction and less than the lower limit of the predetermined range on the other side of the first direction. The third synthetic transmittance distribution protrudes towards the side with higher transmittance in such a way that the transmittance on one side and the other side of the first direction is less than the lower limit of the predetermined range, or protrudes towards the side with lower transmittance in such a way that the transmittance on one side and the other side of the first direction is greater than the upper limit of the predetermined range.

25. The filter unit according to claim 24, wherein, The first filter has a non-uniform first transmittance distribution along a second direction orthogonal to the first direction in the region where the illumination light is incident. The second filter has a non-uniform second transmittance distribution along the second direction in the region where the illumination light is incident. The third filter has a third transmittance distribution that is non-uniform in the first direction along the second direction in the region where the illumination light is incident.

26. The filter unit according to claim 24 or 25, wherein, The first synthetic transmittance distribution is approximately fixed. The second synthetic transmittance distribution is skewed. The third synthetic transmittance distribution is curved.

27. The filter unit according to any one of claims 24 to 26, wherein, The reference positions of the first filter, the second filter, and the third filter are respectively the positions where the center of the first filter, the center of the second filter, and the center of the third filter are aligned with the optical axis in the first direction.

28. The filter unit according to any one of claims 24 to 27, wherein, The first filter is movable in the first direction. The second filter is movable in the first direction. The third filter is fixed at the reference position in the first direction.

29. The filter unit according to any one of claims 24 to 28, wherein, The regions of the first filter, the second filter, and the third filter are each rectangular.

30. The filter unit according to any one of claims 24 to 29, wherein, The difference between the upper and lower limits of the specified range is less than the difference between the maximum and minimum transmittance of the first transmittance distribution, less than the difference between the maximum and minimum transmittance of the second transmittance distribution, and less than the difference between the maximum and minimum transmittance of the third transmittance distribution.

31. The filter unit according to any one of claims 24 to 30, wherein, The first transmittance distribution bulges either towards the side with high transmittance or towards the side with low transmittance. The second transmittance distribution includes a first region bulging towards the side with high transmittance and a second region bulging towards the side with low transmittance. The third transmittance distribution includes a region that bulges toward the side with low transmittance and corresponds to the first region, and a region that bulges toward the side with high transmittance and corresponds to the second region.

32. The filter unit according to claim 31, wherein, The filter unit is configured such that light from the filter unit is incident on the mask without passing through a lens.

33. A lighting unit comprising: Compound eye lenses positioned on the optical axis; as well as The filter unit according to any one of claims 24 to 32, which provides illumination light incident through the compound eye lens.

34. An exposure apparatus comprising: The first illumination optical system is the illumination optical system of claim 33 for illuminating the mask; A first projection optical system illuminates a substrate with light from the first illumination optical system that has passed through the mask; A second illumination optical system, different from the first illumination optical system, illuminates the mask; as well as A second projection optical system, different from the first projection optical system, illuminates the substrate with light from the second illumination optical system that has passed through the mask. The exposure apparatus moves the substrate along a scanning direction corresponding to the second direction while continuously exposing it through the first projection optical system and the second projection optical system.

35. An exposure apparatus comprising: The illumination optical system of claim 33 for illuminating a mask; as well as A projection optical system that illuminates a substrate with light from the illumination optical system passing through the mask. The exposure apparatus scans and exposes a first region of the substrate by means of the projection optical system while moving the substrate along a scanning direction corresponding to the second direction. Then, it scans and exposes a second region of the substrate by means of the projection optical system while moving the substrate along a direction parallel to the scanning direction. This second region of the substrate partially overlaps with the first region and is different from the first region.

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