JP6663914B2 - Illumination device for exposure, exposure device and exposure method - Google Patents

Description

  The present invention relates to an illumination device for exposure, an exposure device, and an exposure method.

  In a conventional exposure apparatus, a curvature correction mechanism for correcting the curvature of a reflecting mirror is provided in an illuminating device, and the shape of an exposure pattern is changed by bending the reflecting mirror to change the decrement angle of the reflecting mirror. Have been devised to obtain a highly accurate exposure result (for example, see Patent Document 1).

  Further, the exposure apparatus described in Patent Document 2 includes an illuminance distribution correction filter including a plurality of liquid crystal cells, and controls each liquid crystal cell to control the illuminance distribution correction filter. It is disclosed that the light transmittance distribution is corrected, the illuminance distribution of light applied to a plurality of lens elements of a fly-eye lens is quickly updated, and the illuminance distribution of light applied to a reticle is made uniform.

Japanese Patent Application Laid-Open No. 2012-155086 Japanese Patent Application Laid-Open No. 2006-210553

  By the way, when the curvature of the reflecting mirror is corrected by the curvature correcting mechanism (mirror bending mechanism), the reflected light is diffused and the illuminance is reduced (darkens) in the portion where the reflecting surface of the reflecting mirror becomes convex, and the reflecting mirror is darkened. In the portion where the reflection surface is concave, the reflected light converges and the illuminance increases (brightens), the illuminance distribution on the exposure surface varies, and the exposure accuracy may be affected. The exposure apparatus described in Patent Literature 2 is an apparatus that controls each liquid crystal cell of an illuminance distribution correction filter to make the illuminance distribution of light applied to a reticle uniform, and that the illuminance distribution varies due to the curvature correction of the reflector. Is not mentioned.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an illumination apparatus for exposure and an exposure apparatus capable of suppressing a variation in illuminance distribution on an exposure surface due to a bending of a mirror by using an optical filter. And an exposure method.

The above object of the present invention is achieved by the following configurations.
(1) a light source,
a fly-eye lens having a plurality of lens elements arranged in a matrix of p rows and q columns (p and q are integers), and uniformly emitting light from the light source;
With a mirror bending mechanism capable of changing the shape of the reflecting surface, a reflecting mirror that reflects the light emitted from the fly-eye lens,
With
An exposure illuminating device that irradiates exposure light from the light source onto a work through a mask on which an exposure pattern is formed and exposes and transfers the exposure pattern to the work,
Further comprising an optical filter arranged between the light source and the fly-eye lens and capable of changing the illuminance distribution on the exposure surface,
The optical filter is arranged in a matrix of p−2 to p + 2 rows and q−2 to q + 2 columns, and has a plurality of cells each having a light transmittance distribution,
The illumination device for exposure, wherein the optical filter is movable in a direction orthogonal to an optical axis of the light.
(2) The illumination device for exposure according to (1), wherein the optical filter includes the plurality of cells arranged in a matrix of p + 2 rows and q + 2 columns.
(3) The cells in the two rows arranged around the optical filter are designed so as to be at least half as large as the cells arranged inside the optical filter in the size in the column direction,
The two columns of cells arranged around the optical filter are designed so that the size in the row direction is half or more of the cells arranged inside the optical filter (2). The illumination device for exposure as described in (1).
(4) The illumination device for exposure according to (1), wherein the optical filter includes the plurality of cells arranged in a matrix of p + 1 rows and q + 1 columns.
(5) Each of the cells has the same light transmittance distribution,
The optical filter is moved in a direction perpendicular to the optical axis of the light according to the shape of the reflecting surface of the reflecting mirror so that the illuminance distribution on the exposure surface is uniform (1). The illumination device for exposure according to any one of (1) to (4).
(6) The exposure illuminating device according to (5), wherein each of the cells has a light transmittance distribution in which light transmittance gradually increases from a central portion to a peripheral portion.
(7) The illumination device for exposure according to any one of (1) to (6), wherein the optical filter is movable along an optical axis of the light.
(8) The illumination device for exposure according to any one of (1) to (7), wherein a plurality of the optical filters are arranged along the optical axis of the light.
(9) a mask support for supporting the mask;
A work supporting portion for supporting the work,
(1) the illumination device for exposure according to any one of (8);
With
An exposure apparatus, comprising: irradiating exposure light from the light source onto the work via the mask to expose and transfer an exposure pattern of the mask onto the work.
(10) The exposure apparatus according to (9), wherein the work is irradiated with exposure light from the light source through the mask to expose and transfer an exposure pattern of the mask onto the work. Exposure method.
(11) The method according to (10), wherein the optical filter is moved in a direction orthogonal to an optical axis of the light while irradiating the work with the exposure light from the light source through the mask. Exposure method according to the above.

  ADVANTAGE OF THE INVENTION According to the illumination device for exposure of this invention, the reflection provided with the light source, the fly-eye lens which has several lens elements arranged in the matrix of p row and q column, and the mirror bending mechanism which changes the shape of a reflection surface A mirror, and a plurality of cells arranged in a matrix of p-2 to p + 2 rows and q-2 to q + 2 columns, each having a light transmittance distribution, and arranged between the light source and the fly-eye lens. An optical filter movable in a direction orthogonal to the optical axis. This makes it possible to move the optical filter in a direction perpendicular to the optical axis, thereby correcting variations in the illuminance distribution on the exposure surface. As a result, variations in the illuminance distribution on the exposure surface due to the change in the shape of the reflection surface due to the mirror bending mechanism can be suppressed by the optical filter.

  According to the exposure apparatus and the exposure method of the present invention, the mask supported by the mask support, the work supported by the work support, and the exposure surface caused by the change in the shape of the reflection surface by the mirror bending mechanism are used. An exposure illuminating device having an optical filter capable of correcting variation in illuminance distribution, and irradiating the work with exposure light from a light source corrected by the optical filter through a mask to transfer an exposure pattern onto the work. Therefore, a highly accurate exposure result can be obtained.

1 is a front view of an exposure apparatus according to the present invention. It is a figure showing composition of a lighting installation concerning the present invention. (A) is a perspective view showing a fly-eye lens and an optical filter of the lighting device, and (b) is a plan view of an optical filter having the same light transmittance distribution and including a plurality of cells arranged in a matrix. It is. (A) is a plan view showing a reflector supporting structure of the lighting device, (b) is a cross-sectional view along the line IV-IV of (a), and (c) is an IV ′ of (a). FIG. 4 is a cross-sectional view along the line IV ′. (A) shows the illuminance on the exposure surface of the light emitted from each lens element when the light having substantially uniform illuminance emitted from the light source unit is corrected by an optical filter and is incident on each lens element of the fly-eye lens. FIG. 3B is a diagram illustrating an image of the overall illuminance on the exposure surface. FIG. 7A is a plan view illustrating an illuminance distribution on the exposure surface when the mirror bending mechanism corrects the trapezoidal irradiation area, and FIG. 8B is a plan view illustrating the corrected illuminance distribution on the exposure surface. FIG. 7 is a plan view showing a positional relationship between an optical filter for correcting the illuminance distribution shown in FIG. 6A and a fly-eye lens. FIG. 7A is a plan view illustrating an illuminance distribution on an exposure surface when the mirror bending mechanism corrects the shape of the irradiation area, and FIG. 8B is a plan view illustrating the corrected illuminance distribution on the exposure surface. FIG. 9 is a plan view showing a positional relationship between an optical filter for correcting the illuminance distribution shown in FIG. 8A and a fly-eye lens. FIG. 7A is a plan view showing an illuminance distribution on an exposed surface when the mirror bending mechanism corrects an irradiation area in a pincushion shape, and FIG. 7B is a plan view showing an illuminance distribution on the corrected exposed surface. FIG. 11 is an enlarged view showing a positional relationship between an optical filter for correcting the illuminance distribution shown in FIG. 10A and a fly-eye lens. (A) is a plan view showing the illuminance distribution of the exposed surface in which the illuminance of the portion corresponding to the region of the reflective surface having a small radius of curvature is increased, and (b) is a plan view showing the corrected illuminance distribution of the exposed surface. It is. It is a top view showing the 1st modification of an optical filter with the positional relationship of a fly-eye lens. FIG. 11 is a plan view showing a second modification of the optical filter together with the positional relationship of the fly-eye lens. (A) is a plan view showing a third modified example of the optical filter together with the positional relationship of the fly-eye lens, and (b) is a plan view showing a fourth modified example of the optical filter together with the positional relationship of the fly-eye lens. It is a top view of the 5th modification of an optical filter.

  Hereinafter, an embodiment of an exposure apparatus according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the proximity exposure apparatus PE uses a mask M smaller than a work W as a material to be exposed, holds the mask M on a mask stage (mask supporting portion) 1, and also moves the work W to a work stage (workpiece). By holding the mask M and the workpiece W close to each other and facing each other at a predetermined exposure gap, the mask M is irradiated with light for pattern exposure from the illuminating device 3 toward the mask M. The pattern M is exposed and transferred onto the work W. Further, the work stage 2 is moved stepwise with respect to the mask M in two axial directions of the X-axis direction and the Y-axis direction, and exposure transfer is performed for each step.

  In order to move the work stage 2 stepwise in the X-axis direction, an X-axis stage feed mechanism 5 that moves the X-axis feed base 5a in the X-axis direction is provided on the device base 4. On the X-axis feeder 5a of the X-axis stage feeder 5, a Y-axis stage feeder 6 for step-moving the Y-axis feeder 6a in the Y-axis direction in order to move the work stage 2 in the Y-axis direction is installed. Have been. The work stage 2 is installed on the Y-axis feed base 6a of the Y-axis stage feed mechanism 6. The work W is held on the upper surface of the work stage 2 in a state where the work W is vacuum-sucked by a work chuck or the like. A substrate-side displacement sensor 15 for measuring the height of the lower surface of the mask M is provided on the side of the work stage 2. Therefore, the substrate-side displacement sensor 15 can move in the X and Y axis directions together with the work stage 2.

  A plurality of (four in the illustrated embodiment) X-axis linear guide guide rails 51 are arranged in the X-axis direction on the device base 4, and each of the guide rails 51 has a lower surface of the X-axis feed base 5a. Is mounted on the slider 52. As a result, the X-axis feed base 5 a is driven by the first linear motor 20 of the X-axis stage feed mechanism 5 and is capable of reciprocating in the X-axis direction along the guide rail 51. A plurality of guide rails 53 for Y-axis linear guides are arranged on the X-axis feed base 5a in the Y-axis direction. Each guide rail 53 has a slider 54 fixed to the lower surface of the Y-axis feed base 6a. Is straddled. As a result, the Y-axis feed base 6 a is driven by the second linear motor 21 of the Y-axis stage feed mechanism 6 and is capable of reciprocating in the Y-axis direction along the guide rail 53.

  Between the Y-axis stage feed mechanism 6 and the work stage 2, the work stage 2 is moved in the vertical direction. An up-down fine movement device 8 is provided which can perform positioning at a higher resolution than the device 7 and finely moves the work stage 2 up and down to finely adjust the gap between the opposing surfaces of the mask M and the work W to a predetermined amount. .

  The up-down coarse movement device 7 moves the work stage 2 up and down with respect to the fine movement stage 6b by an appropriate drive mechanism provided on the fine movement stage 6b described later. Stage coarse movement shafts 14 fixed to four locations on the bottom surface of the work stage 2 engage with linear motion bearings 14a fixed to the fine movement stage 6b, and are guided vertically with respect to the fine movement stage 6b. It is desirable that the vertical coarse movement device 7 has high repeatability even if the resolution is low.

  The vertical fine movement device 8 includes a fixed base 9 fixed to the Y-axis feed base 6a, and a guide rail 10 of a linear guide mounted on the fixed base 9 with its inner end inclined obliquely downward. A nut (not shown) of a ball screw is connected to a slide body 12 that reciprocates along the guide rail 10 via a slider 11 laid on the guide rail 10, and an upper end surface of the slide body 12. Is horizontally slidably in contact with the flange 12a fixed to the fine movement stage 6b.

Then, when the screw shaft of the ball screw is rotationally driven by the motor 17 attached to the fixed base 9, the nut, the slider 11 and the slide body 12 integrally move in the oblique direction along the guide rail 10, whereby And the flange 12a slightly moves up and down.
The vertical fine movement device 8 may drive the slide body 12 by a linear motor instead of driving the slide body 12 by a motor 17 and a ball screw.

The vertical fine movement device 8 is provided at one end (left end side in FIG. 1) in the Y-axis direction of the Z-axis feed base 6a, and two at the other end, for a total of three units. It has become so. Thus, the vertical fine movement device 8 independently fine-adjusts the heights of the three flanges 12a based on the measurement results of the gap amounts between the mask M and the work W at a plurality of positions by the gap sensor 27, and Fine-tune the height and tilt of the
When the height of the work stage 2 can be sufficiently adjusted by the vertical fine movement device 8, the vertical coarse movement device 7 may be omitted.

  A bar mirror 19 facing the Y-axis laser interferometer 18 for detecting the Y-direction position of the work stage 2 and an X-axis laser for detecting the X-axis position of the work stage 2 are provided on the Y-axis feed base 6a. A bar mirror (both not shown) facing the interferometer is provided. The bar mirror 19 facing the Y-axis laser interferometer 18 is arranged along the X-axis direction on one side of the Y-axis feed base 6a, and the bar mirror facing the X-axis laser interferometer is located on the Y-axis feed base 6a. One end side is arranged along the Y-axis direction.

  The Y-axis laser interferometer 18 and the X-axis laser interferometer are arranged so as to always face the corresponding bar mirrors, respectively, and are supported by the apparatus base 4. Note that two Y-axis laser interferometers 18 are installed apart from each other in the X-axis direction. The two Y-axis laser interferometers 18 detect the Y-axis position of the Y-axis feed table 6a and, consequently, the Y-axis direction and the yawing error of the work stage 2 via the bar mirror 19. Further, the X-axis laser interferometer detects the position of the X-axis feed base 5a, and thus the work stage 2, in the X-axis direction via the bar mirror facing the X-axis laser interferometer.

  The mask stage 1 includes a mask base frame 24 formed of a substantially rectangular frame body, and is inserted into a central opening of the mask base frame 24 with a gap therebetween in the X, Y, and θ directions (in the X, Y plane). The mask base frame 24 is movably supported, and the mask base frame 24 is held at a fixed position above the work stage 2 by a column 4 a protruding from the apparatus base 4.

  On the lower surface of the central opening of the mask frame 25, a frame-shaped mask holder 26 is provided. That is, a plurality of mask holder suction grooves connected to a vacuum suction device (not shown) are provided on the lower surface of the mask frame 25, and the mask holder 26 is suctioned to the mask frame 25 via the plurality of mask holder suction grooves. Will be retained.

  On the lower surface of the mask holder 26, a plurality of mask suction grooves (not shown) for suctioning a peripheral portion of the mask M on which the mask pattern is not drawn are opened. It is detachably held on the lower surface of the mask holder 26 by a vacuum suction device (not shown).

  As shown in FIG. 2, the illumination device 3 of the exposure apparatus PE of the present embodiment includes, for example, a high-pressure mercury lamp 61 that is a light source for irradiating ultraviolet rays, and a reflector 62 that condenses the light emitted from the high-pressure mercury lamp 61. , A planar mirror 63 for changing the direction of the optical path EL, and an optical filter 90 (including a plurality of cells 91 each having the same light transmittance distribution and arranged in a matrix). FIG. 3), an exposure control shutter unit 64 for controlling the opening and closing of the irradiation optical path, and a plurality of lens elements 65 a arranged downstream of the exposure control shutter unit 64 and arranged in a matrix. A fly-eye lens 65 for emitting the condensed light so that the illuminance distribution is as uniform as possible in the irradiation area; A plane mirror 66 for changing the direction of the optical path EL emitted from the eye lens 65, a collimation mirror 67 for irradiating the light from the high-pressure mercury lamp 61 as parallel light, and a plane for irradiating the parallel light toward the mask M A mirror 68.

  As shown in FIG. 3A, the optical filter 90 is movable in two directions along a plane orthogonal to the optical path EL and in a direction along the optical path EL. Specifically, the optical filter 90 is movable in each direction by driving a frame 92 provided around the optical filter 90 by a driving device 93. Further, the driving device 93 can also move the optical filter 90 to a position in an unused state where the optical filter 90 is retracted from the optical path EL. The optical filter 90 can adjust the intensity of illuminance on the exposure surface by moving the optical filter 90 along the optical path EL. For example, the closer the optical filter 90 is to the fly-eye lens 65, the more the illuminance on the exposure surface can be further reduced by the portion where the light transmittance of each cell 91 is low.

Further, the optical filter 90 can be inclined with respect to the fly-eye lens 65. Specifically, the optical filter 90 can be tilted by swinging around an arbitrary axis CL extending in a direction orthogonal to the optical path EL. By inclining the optical filter 90 with respect to the fly-eye lens 65, the influence on the illuminance on the exposure surface due to the portion approaching the fly-eye lens 65 is increased, and the illuminance on the exposure surface due to the portion distant from the fly-eye lens 65. The effect on the environment is weakened.
Further, the influence on the illuminance on the exposure surface may be changed by bending the optical filter 90.

  As shown in FIG. 3B, each of the plurality of cells 91 of the optical filter 90 has a light transmittance at the center lower than the light transmittance at the periphery, specifically, from the center toward the periphery. Have the same light transmittance distribution in which the light transmittance gradually increases.

  The change in light transmittance from the center to the periphery can be arbitrarily set, such as a linear change, a sinusoidal change, an exponential change, and a Gaussian change. The light transmittance distribution can be provided by depositing a chromium dot pattern on the quartz substrate of the optical filter 90, an optical filter whose transmittance changes radially from the center by a deposited multilayer film, or the like. The light transmittance can be arbitrarily set by changing the size and density of the dot pattern. The shape of the dot pattern can be set arbitrarily, such as a rectangle, a circle, and an ellipse. The material of the optical filter 90 is desirably a quartz substrate, but may be soda glass.

The cell 91 of the optical filter 90 has substantially the same size as the lens element 65a of the fly-eye lens 65. The plurality of cells 91 of the optical filters 90 arranged in a matrix are larger than the plurality of lens elements 65a of the fly-eye lens 65 arranged in a matrix by two rows and two columns. That is, when the lens elements 65a of the fly-eye lens 65 are arranged in a matrix of p rows and q columns (p and q are integers), the cells 91 of the optical filter 90 have a matrix of p + 2 rows and q + 2 columns. Are arranged.
Note that the lens element 65a of the fly-eye lens 65 and the cell 91 of the optical filter 90 are arranged such that the directions of the rows and columns thereof match each other.

  Therefore, the optical filter 90 shown in FIG. 3B in which the cells 91 are arranged in a matrix of 5 columns and 5 rows is a fly-eye lens 65 in which the lens elements 65a are arranged in a matrix of 3 columns and 3 rows. Available. Thus, even if the optical filter 90 is moved within a range of one cell in a direction orthogonal to the optical path EL, the entire surface of the lens element 65a of the fly-eye lens 65 faces the cell 91 of the optical filter 90.

  Note that the optical filter 90 may be changeable to an optical filter 90 having another light transmittance distribution by a switching mechanism (not shown). Further, if necessary, the optical filter 90 can be cooled by blowing cooling air from a nozzle (not shown). When cooling the periphery of the optical filter 90, cooling may be performed by circulating cooling water around a frame 92 provided around the optical filter 90.

  In addition, in the lighting device 3, the high-pressure mercury lamp 61 may be a single lamp, or may be configured by an LED. Further, the order of installation of the optical filter 90 and the exposure control shutter unit 64 may be reversed. Further, a DUV cut filter, a polarization filter, and a band pass filter may be arranged between the fly-eye lens 65 and the exposure surface.

  Further, as shown in FIG. 4, the plane mirror 68 is made of a glass material formed in a rectangular shape when viewed from the front. The plane mirror 68 is supported by a mirror deformation unit holding frame 71 by a plurality of mirror deformation units (mirror bending mechanisms) 70 provided on the back side of the plane mirror 68.

  Each mirror deformation unit 70 includes a pad 72 fixed to the back surface of the plane mirror 68 with an adhesive, a support member 73 having one end fixed to the pad 72, and an actuator 74 for driving the support member 73.

  The support member 73 is provided with a ball joint 76 as a bending mechanism that allows bending of ± 0.5 deg or more at a position near the pad 72 with respect to the holding frame 71. An actuator 74 is attached to the other end.

  Further, a plurality of contact sensors 77 are mounted on the back surface of each position of the plane mirror 68 that reflects the exposure light to the position of the alignment mark (not shown) on the mask side.

  Accordingly, the plane mirror 68 senses the displacement of the plane mirror 68 by the contact sensor 77 based on a command from the mirror controller 80 connected to each actuator 74 via the signal line 81 (see FIG. 2). By changing the length of each support member 73 by driving the actuator 74 of each mirror deformation unit 70 to change the shape of the plane mirror 68 and locally changing the curvature of the reflection surface, 68 can be corrected.

  At this time, since each mirror deforming unit 70 is provided with the ball joint 76, the portion on the support portion side can be three-dimensionally rotatable, and each pad 72 is placed on the surface of the plane mirror 68. Can be tilted along. For this reason, it is possible to prevent the peeling of the adhesive between the pads 72 and the plane mirror 68, and to suppress the stress of the plane mirror 68 between the pads 72 having different movement amounts, so that the pad 72 is made of a glass material having a small average fracture stress value. Even when the plane mirror 68 is locally changed in shape, the plane mirror 68 can be bent on the order of 10 mm without damaging the plane mirror 68, and the curvature can be largely changed.

  In the exposure apparatus PE configured as described above, when the exposure control shutter unit 64 is controlled to open during the exposure in the illumination apparatus 3, the light emitted from the high-pressure mercury lamp 61 is reflected by the plane mirror 63 and fly. The light enters the entrance surface of the eye lens 65. Then, the light emitted from the exit surface of the fly-eye lens 65 has its traveling direction changed by a plane mirror 66, a collimation mirror 67, and a plane mirror 68 and is converted into parallel light. Then, the parallel light is irradiated as light for pattern exposure substantially perpendicularly to the mask M held on the mask stage 1 and further to the surface of the work W held on the work stage 2, and the pattern of the mask M is changed. Exposure is transferred onto the work W.

  Here, a drive signal is transmitted from the mirror control unit 80 to each actuator 74 of the plane mirror 68 in order to correct the pattern of the mask M exposed and transferred onto the work W corresponding to the exposed pattern of the work W. Then, the actuator 74 of each mirror deforming unit 70 changes the length of each support member 73, locally changes the shape of the plane mirror 68, and corrects the decrement angle of the plane mirror 68.

  At this time, the illuminance of the exposure light applied to the mask M locally changes due to the local shape change of the plane mirror 68. That is, the illuminance distribution on the exposure surface is deteriorated, which may affect the exposure accuracy of the work W. Specifically, in a portion where the flat mirror 68 is pushed from the back surface by the actuator 74 and the reflection surface of the flat mirror 68 becomes convex, the reflected light is diffused and the illuminance is reduced (darkens). Further, in the portion where the back surface of the plane mirror 68 is pulled by the actuator 74 and the reflection surface of the plane mirror 68 becomes concave, the reflected light converges and the illuminance is increased (brightened).

  On the other hand, as shown in FIG. 5A, the optical filter 90 including a plurality of cells 91 whose light transmittance at the central portion is lower than that at the peripheral portion, when moved in a direction orthogonal to the optical path EL, causes each cell to move. Light passing through the portion 91 (lower center) of the light transmittance 91 overlaps through each lens element 65a of the fly-eye lens 65, so that the illuminance distribution on the exposure surface changes, and a part of the light on the exposure surface is changed. Illuminance decreases (FIG. 5B).

  For this reason, the optical filter 90 is arranged on the optical path EL, and the shape of the plane mirror 68 is changed so that the central portion of the cell 91 where the light transmittance of the cell 91 is low is located at the portion of each lens element 65a corresponding to the portion where the illuminance is high on the exposure surface. The optical filter 90 is moved so as to face each other. Thereby, the variation in the illuminance distribution on the exposure surface can be corrected by lowering the illuminance of the high illuminance using the optical filter 90, and the illuminance distribution can be improved.

  Note that when the number (the number of eyes) of the lens elements 65a arranged in a matrix of the fly-eye lens 65 increases, the number is averaged, and the change in the illuminance distribution on the exposure surface also decreases. The number of the lens elements 65 a may be appropriately set from three or more arranged in the vertical direction and three or more in the horizontal direction. It is appropriately designed according to the number of the elements 65a.

  Hereinafter, a simulation result in which the illuminance distribution is corrected by using the optical filter 90 when the shape of the plane mirror 68 is changed will be described with reference to FIGS.

  For example, in FIG. 6A, the irradiation area becomes substantially trapezoidal due to the change in the shape of the plane mirror 68, and the illuminance distribution of the exposure light on the exposure surface (on the work W) is substantially uniform in the horizontal direction of the exposure surface. In the vertical direction, the lower part is lowered. As shown in FIG. 7, the correction of the illuminance distribution is performed by moving the optical filter 90 relative to the fly-eye lens 65 downward by approximately ／ pitch of the cell 91 in the figure, so that the light transmittance is reduced. The lower central portion of each cell 91 faces the upper part of each lens element 65a of the fly-eye lens 65.

  As a result, as shown in FIG. 6B, the illuminance distribution on the exposed surface is reduced in the illuminance of the high illuminance portion, becomes substantially uniform as a whole, and the exposure accuracy is improved. The intensity of the exposure light at the place where the illuminance is desired to be reduced can be adjusted by moving the optical filter 90 along the optical path EL as needed.

  FIG. 8A shows that the irradiation area has a substantially round shape due to the change in the shape of the plane mirror 68, and the illuminance distribution of the exposure light on the exposure surface decreases at the central portion of the exposure surface. To correct such illuminance distribution, as shown in FIG. 9, the optical filter 90 is moved relative to the fly-eye lens 65 by approximately 1/2 pitch in the vertical direction and approximately 1/2 pitch in the horizontal direction in the figure. Then, the central portion of each cell 91 where the light transmittance is low is opposed to the peripheral portion of each lens element 65a of the fly-eye lens 65. As a result, as shown in FIG. 8B, the illuminance distribution on the exposed surface is substantially uniform as a whole because the illuminance at the peripheral portion where the illuminance is high is reduced.

  FIG. 10A shows that the irradiation area has a substantially pincushion shape due to the change in the shape of the plane mirror 68, and the illuminance distribution of the exposure light on the exposure surface is higher at the center of the exposure surface. In such correction of the illuminance distribution, the positions of the lens elements 65a of the fly-eye lens 65 and the cells 91 of the optical filter 90 are matched, as shown in FIG. Thereby, as shown in FIG. 10B, the illuminance distribution on the exposed surface is reduced substantially at the central portion where the illuminance is high, and becomes substantially uniform as a whole.

  In FIG. 12A, the shape change of the plane mirror 68 increases the illuminance distribution of the upper left portion (the portion surrounded by a circle C in the drawing) of the exposure surface irradiated by the concave curved portion having a small radius of curvature. I have. In such correction of the illuminance distribution, the light transmittance of each cell 91 of the optical filter 90 is low at the position of each lens element 65a of the fly-eye lens 65 that irradiates a portion of the plane mirror 68 having a small radius of curvature. The optical filter 90 is moved so that the portions match. Thereby, as shown in FIG. 12B, the illuminance distribution on the exposure surface is reduced in the upper left portion where the illuminance is high, and becomes substantially uniform as a whole.

  As described above, according to the illumination device 3 of the present embodiment, the lamp unit 60, the fly-eye lens 65 having the plurality of lens elements 65a arranged in a matrix of p rows and q columns, and the reflection surface A flat mirror 68 having a mirror deformation unit 70 for changing the shape, and a plurality of cells 91 arranged in a matrix of p + 2 rows and q + 2 columns, each having a light transmittance distribution, have a lamp unit 60 and a fly-eye lens. And an optical filter 90 disposed between the optical filter 65 and the optical filter 90 and movable in a direction orthogonal to the optical path EL. Thus, the illuminance on the exposure surface can be changed by moving the optical filter 90 in a direction orthogonal to the optical path EL, and the illuminance distribution can be corrected. As a result, the variation in the illuminance distribution on the exposure surface due to the change in the shape of the reflection surface by the mirror deformation unit 70 can be suppressed by the optical filter 90.

  Each cell 91 has the same light transmittance distribution, and moves the optical filter 90 in a direction orthogonal to the optical path EL according to the shape of the reflection surface so that the illuminance distribution on the exposure surface is uniform. Accordingly, the work W can be uniformly exposed by correcting the illuminance distribution irrespective of the bending direction (irregularity) of the reflecting surface, the magnitude of the curvature correction, and the like.

  Further, since each cell 91 has a light transmittance distribution in which the light transmittance gradually increases from the central portion to the peripheral portion, the center of each cell 91 is located at the portion where the illuminance is increased by changing the shape of the reflecting surface. The illuminance can be made uniform by lowering the illuminance of the high illuminance portion by matching the portions.

  Further, since the optical filter 90 is movable along the optical path EL, the intensity of illuminance on the exposure surface can be adjusted.

  Further, according to the exposure apparatus PE and the exposure method of the present embodiment, the mask M supported by the mask stage 1, the work W supported by the work stage 2, and the change in the shape of the reflection surface by the mirror deformation unit 70. An illumination device 3 having an optical filter 90 capable of correcting variations in the illuminance distribution on the exposure surface to be exposed. The exposure light from the lamp unit 60 is corrected by the optical filter 90, and the work W is irradiated onto the work W via the mask M. Then, the exposure pattern is exposed and transferred to the work W, so that a highly accurate exposure result can be obtained.

  In the above embodiment, each cell 91 of the optical filter 90 is designed to have the same size. However, in the present invention, as shown in FIG. 13, the upper and lower two rows of cells 91 arranged around the optical filter 90 are arranged inside the optical filter 90 in the size in the column direction (vertical direction). The cell 91 may be designed to be half or more (half in FIG. 12). In addition, the right and left two columns of cells 91 arranged around the optical filter 90 are half or more (half in FIG. 12) the cells 91 arranged inside the optical filter 90 in the size in the row direction (horizontal direction). ) May be designed. Thus, the optical filter 90 shown in FIG. 13 can be made smaller by one cell in the vertical and horizontal directions as compared with the optical filter 90 shown in FIG. 3B. In this case, each cell 91 disposed around the optical filter 90 is provided by cutting a cell having the same light transmittance distribution as the cell 91 disposed inside into a predetermined size.

  In the present invention, as shown in FIG. 14, the optical filter 90 has a plurality of cells 91 arranged in a matrix of p + 1 rows and q + 1 columns, each having the same light transmittance distribution. Is also good. That is, the optical filter 90 moves one cell in the row direction (left-right direction) (rightward in FIG. 14) with respect to the cell 91 in the p-row corresponding to the lens element 65a in the p-row of the fly-eye lens 65. One of the cells 91 in the row is arranged, and the cell 91 in the q column corresponding to the lens element 65a in the q column of the fly-eye lens 65 is placed in one of the column directions (downward in FIG. 14). The configuration may be such that the cells 91 in one row are arranged in one row. Also in this case, similarly to the optical filter 90 of the above embodiment, the illuminance on the exposure surface can be changed by moving the optical filter 90 relative to the fly-eye lens 65 in a direction orthogonal to the optical path EL.

  In the present invention, as shown in FIG. 15A, the optical filters 90 are arranged in a matrix of p−2 rows and q−2 columns, and a plurality of cells each having the same light transmittance distribution are provided. 91 may be provided. In this case, among the lens elements 65a of the p-row and q-column of the fly-eye lens 65, the lens elements 65a located in the upper and lower two rows and the left and right two columns correspond to the lens elements 65a. Since there is no cell 91, the illuminance cannot be reduced. However, compared to the central lens element 65a, the illuminance of the irradiation light emitted from the outer peripheral lens element 65a is dark, and thus the practical effect is small. For this reason, in the case of the modified example, similarly to the optical filter 90 of the above embodiment, the illuminance on the exposure surface is reduced by moving the optical filter 90 relative to the fly-eye lens 65 in a direction perpendicular to the optical path EL. Can be changed.

Further, as shown in FIG. 15B, the optical filter 90 has a plurality of cells 91 arranged in a matrix of p-1 rows and q-1 columns, each having the same light transmittance distribution. It may be. Also in this case, among the lens elements 65a of the p-row and q-column of the fly-eye lens 65, the lens elements 65a located in the upper and lower rows and the left and right one column correspond to the lens elements 65a. There is no cell 91 to be used, and the illuminance cannot be reduced. However, compared to the central lens element 65a, the illuminance of the irradiation light emitted from the outer peripheral lens element 65a is dark, and thus the practical effect is small. For this reason, in the case of the modified example, similarly to the optical filter 90 of the above embodiment, the illuminance on the exposure surface is reduced by moving the optical filter 90 relative to the fly-eye lens 65 in a direction perpendicular to the optical path EL. Can be changed.
The cells 91 of the optical filter 90 may be the same as the lens elements 65a of the fly-eye lens 65, arranged in a matrix of p rows and q columns.

  As shown in FIG. 16, the optical filter 90 has cells 91A located at the center (3 rows × 3 columns in the figure) and outer cells (2 rows vertically and 2 columns left and right in the figure). Cell 91B. Each of the cells 91A and 91B has a light transmittance distribution in which the light transmittance gradually increases from the central portion to the peripheral portion, and the central portion of the cell 91B in the outer peripheral portion is more than the central portion of each cell 91A in the central portion. Is set to have a higher light transmittance. As described above, since the illuminance of the irradiation light emitted from the lens element 65a in the central portion is strong and the illuminance of the irradiation light emitted from the lens element 65a in the outer peripheral portion is weak, the optical filter 90 is provided. In addition, it is possible to average the influence of the illuminance due to the irradiation light emitted from each lens element 65a.

In the above embodiment, the number of the optical filters 90 is designed to be one. However, two or more optical filters 90 may be arranged side by side along the optical axis of light. Thus, for example, by disposing the two optical filters 90 of the above embodiment at a position shifted from the central portion where the light transmittance is low, the illuminance distribution at a plurality of positions on the exposure surface is adjusted, and the exposure is performed. The illuminance distribution on the surface can be made uniform.
Adjustment of the illuminance distribution at a plurality of locations on the exposure surface can also be achieved by moving the optical filter 90 while the exposure control shutter unit 64 is open.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like.
For example, the light transmittance distribution of the optical filter of the above embodiment has been described on the assumption that the light transmittance of the central portion is lower than the light transmittance of the peripheral portion. An optical filter having a light transmittance distribution higher than the light transmittance of the optical filter may be used. Also in this case, by arranging a portion where the light transmittance of the optical filter is low opposite to a portion where the illuminance on the exposure surface is high, the illuminance distribution on the exposure surface can be uniform.

Further, the position of the optical filter is on the lamp unit side of the fly-eye lens, but it can be arranged between two fly-eye lenses.
Furthermore, although the pitch of the cells of the optical filter has been described as being constant, the light from the lamp unit is not parallel light, but is slightly focused or diffused and enters the fly-eye lens through the optical filter. In such a case, the pitch of each cell of the optical filter may be shifted according to the angle between the parallel light and the optical path.

  The present invention is based on a Japanese patent application filed on May 26, 2015 (Japanese Patent Application No. 2015-106049), the contents of which are incorporated herein by reference.

1 Mask stage (mask support)
2 Work stage (work support)
3 Lighting device (lighting device for exposure)
60 lamp unit (light source)
65 fly-eye lens 65a lens element 68 plane mirror (reflection mirror)
70 Mirror deformation unit (mirror bending mechanism)
90 Optical filter 91 Cell EL Optical path (optical axis)
M Mask PE Proximity exposure apparatus W Work

Claims (10)

Light source,
a fly-eye lens having a plurality of lens elements arranged in a matrix of p rows and q columns (p and q are integers), and uniformly emitting light from the light source;
With a mirror bending mechanism capable of changing the shape of the reflecting surface, a reflecting mirror that reflects the light emitted from the fly-eye lens,
With
An exposure illuminating device that irradiates exposure light from the light source onto a work through a mask on which an exposure pattern is formed and exposes and transfers the exposure pattern to the work,
Further comprising an optical filter arranged between the light source and the fly-eye lens and capable of changing the illuminance distribution on the exposure surface,
The optical filter is arranged in a matrix of p−2 to p + 2 rows and q−2 to q + 2 columns, and has a plurality of cells each having a light transmittance distribution,
Said optical filter, Ri movable der in a direction perpendicular to the optical axis of the light,
Each of the cells has the same light transmittance distribution,
The optical filter is moved in a direction perpendicular to the optical axis of the light according to the shape of the reflecting surface of the reflecting mirror so that the illuminance distribution on the exposure surface is uniform . Lighting equipment.   The illumination apparatus according to claim 1, wherein the optical filter includes the plurality of cells arranged in a matrix of p + 2 rows and q + 2 columns. The two rows of cells arranged around the optical filter are designed to be, in the column size, at least half of the cells arranged inside the optical filter,
The cell in the two columns arranged around the optical filter is designed to have a size in the row direction that is equal to or more than half of the cells arranged inside the optical filter. 3. The illumination device for exposure according to item 2.   The illumination device for exposure according to claim 1, wherein the optical filter includes the plurality of cells arranged in a matrix of p + 1 rows and q + 1 columns. 2. The exposure lighting device according to claim 1 , wherein each of the cells has a light transmittance distribution in which light transmittance gradually increases from a central portion to a peripheral portion. 3. The illumination device according to any one of claims 1 to 5 , wherein the optical filter is movable along an optical axis of the light. The exposure lighting device according to any one of claims 1 to 6 , wherein a plurality of the optical filters are arranged along the optical axis of the light. A mask supporting portion for supporting the mask,
A work supporting portion for supporting the work,
The illumination device for exposure according to any one of claims 1 to 7 ,
With
An exposure apparatus, comprising: irradiating exposure light from the light source onto the work via the mask to expose and transfer an exposure pattern of the mask onto the work. An exposure method, comprising using the exposure apparatus according to claim 8 , irradiating the work with the exposure light from the light source through the mask, and exposing and transferring an exposure pattern of the mask to the work. The exposure according to claim 9 , wherein the optical filter is moved in a direction orthogonal to an optical axis of the light while irradiating the work with the exposure light from the light source through the mask. Method.

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