JP5704527B2 - Exposure system using microlens array - Google Patents

Description

  The present invention relates to an exposure apparatus using a microlens array that exposes a mask pattern onto a substrate by a plurality of microlens arrays in which microlenses are two-dimensionally arranged.

  A thin film transistor liquid crystal substrate, a color filter substrate, and the like form a predetermined pattern by overlaying and exposing a resist film or the like formed on a glass substrate several times. As this exposure apparatus, a scan exposure apparatus using a microlens array in which microlenses are two-dimensionally arranged has been proposed (Patent Document 1). In this scan exposure apparatus, a plurality of microlens arrays are arranged in one direction, and a substrate and a mask are moved relative to the microlens array and the exposure light source in a direction perpendicular to the arrangement direction. Then, the exposure light scans the mask, and the exposure pattern formed in the hole of the mask is imaged on the substrate.

  When this microlens array is manufactured, there is a limit to the size of the microlens array that can be manufactured due to restrictions on the manufacturing apparatus. Therefore, when a large mask is used and the mask pattern is exposed on the substrate, a plurality of microlens arrays are juxtaposed on the support plate, and one mask is formed by the plurality of microlens arrays. It is necessary to perform an exposure process corresponding to.

JP2007-3829A

  However, when the flatness of the support plate supporting the microlens arrays is low, the directions of the surfaces between the microlens arrays do not match, and the optical axes of the microlens arrays are shifted from each other. There was a case. If it does so, the exposure position of a mask pattern will shift from the predetermined position on a board | substrate, and there exists a problem that exposure precision deteriorates or exposure of a large area becomes difficult.

  The present invention has been made in view of such a problem, and in an exposure apparatus using a plurality of microlens arrays, when the flatness of a support plate supporting the microlens arrays is low and the exposure target on the substrate is An object of the present invention is to provide an exposure apparatus using a microlens array that can align the optical axes of the microlens arrays with high accuracy even when they are shifted.

An exposure apparatus using the microlens array according to the present invention is:
An exposure light source;
A mask that blocks exposure light from the exposure light source by an exposure pattern;
A plurality of microlens arrays disposed between the substrate to be exposed and the mask , each having a plurality of microlenses arranged two-dimensionally;
A support plate on which the plurality of microlens arrays are disposed;
A piezoelectric element provided for at least one microlens array on the support plate;
Have
The plurality of microlens arrays are arranged such that the intervals of all the microlenses are the same in the direction orthogonal to the relative scanning direction between the substrate and the mask and the microlens array. ,
At least three of the piezoelectric elements are arranged for each microlens array provided with the piezoelectric elements, the base ends of the piezoelectric elements are fixed on the support plate, and the tips of the piezoelectric elements are fixed to the microlens array. Is supported by at least three points,
The optical axis of each microlens array can be adjusted by adjusting the voltage applied to the piezoelectric element.

The microlens exposure apparatus using an array, for example, pre-Symbol microlens is designed to project the erect image of the exposure pattern of the mask on the substrate.

  According to the present invention, in the exposure apparatus using the microlens array, the microlens array is supported by the piezoelectric element at least at three points. Therefore, by adjusting the voltage applied to the piezoelectric element, the piezoelectric element Is deformed, and the support point of the microlens array with respect to the support plate can be raised or lowered. Therefore, the optical axis of the microlens array can be adjusted by adjusting the degree of deformation of the at least three piezoelectric elements that support one microlens array by adjusting the applied voltage.

  Therefore, when piezoelectric elements are arranged in all the microlens arrays, the optical axes between all the microlens arrays can be matched by adjusting the optical axes of all the microlens arrays, When a piezoelectric element is arranged in some microlens arrays, the optical axis of the microlens array in which the piezoelectric element is arranged is made to coincide with the optical axis of the microlens array in which no piezoelectric element is arranged. By adjusting the voltage applied to the piezoelectric element, the optical axes between all the microlens arrays can be made coincident. As a result, even if the flatness of the support plate that supports the microlens array is low or the exposure target on the substrate is shifted, the optical axes of the plurality of microlens arrays can be made coincident. High-precision exposure can be performed on a substrate having an area.

1 is a schematic perspective view showing an exposure apparatus according to an embodiment of the present invention. It is a longitudinal cross-sectional view which shows the part of one micro lens array of the exposure apparatus which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which similarly shows the operation | movement. It is sectional drawing which shows typically the relationship between a micro lens array and a mask. It is also the perspective view, It is a figure which shows the structure of one micro lens. (A), (b) is a figure which shows the aperture_diaphragm | restriction of a micro lens array. It is a top view which shows arrangement | positioning of the hexagonal field stop of a micro lens.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic perspective view showing an exposure apparatus according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a part of one microlens array, and FIG. 3 is a longitudinal sectional view showing the operation of the same. It is. In the exposure apparatus of this embodiment, a plurality of microlens arrays 2 (2b, 2c) are supported and arranged on a support plate 1, and supported above the microlens array 2 by a support plate 5. One mask 6 is arranged. In the microlens array 2, a plurality of microlenses 2a are two-dimensionally arranged. This mask 6 has a Cr film 6b as a light shielding film formed on the lower surface of a transparent substrate 6a. An exposure pattern to be exposed on the substrate 22 is formed in a hole formed in the Cr film 6b. . The exposure light emitted from the exposure light source 20 passes through the mask 6, and the exposure pattern formed in the hole of the Cr film 6 b of the mask 6 forms an image on the substrate 22 by the microlens array 2. For example, the microlens array 2 is fixed to the exposure apparatus, and the mask 6 and the substrate 22 to be exposed move relative to the microlens array 2 in the scanning direction 50, so that the entire region of the substrate 22 is obtained. The exposure pattern of the mask 6 is exposed through the microlens array 2. It is also possible to scan the substrate with exposure light by moving the microlens array 2 and the exposure light source with respect to the mask 6 and the substrate 22.

  As shown in FIG. 1, the microlens array 2 is arranged on the support plate 1 in two rows of a microlens array 2 b and a microlens array 2 c so as to form a row in a direction perpendicular to the scanning direction 50. In addition, the microlens array 2 b and the microlens array 2 c are arranged so as to be shifted from each other in the scanning direction 50. As shown in FIGS. 2 and 3, the microlens array 2 is disposed in a hole 1 a provided in the support plate 1, and each hole 1 a has a size corresponding to the outer shape of each microlens array 2. have. In the direction orthogonal to the scanning direction 50, the microlens array 2 is arranged so that adjacent microlens arrays 2 (microlens array 2b and microlens array 2c) are close to each other. The portion of the support plate 1 between the microlens arrays 2 adjacent to each other in the direction orthogonal to the scan direction 50 is extremely thin, and the end of the microlens array 2 in the direction orthogonal to the scan direction 50 is the end. The distance between the microlenses 2a and the edge is shorter than 1/2 of the arrangement pitch of the microlenses 2a. For this reason, as shown in FIG. 1, each microlens array 2 is connected between the microlenses 2 a of all the microlens arrays 2 in the direction orthogonal to the scan direction 50 even if the microlens arrays 2 are continuous in the direction orthogonal to the scan direction 50 Can be made the same interval. That is, the pitch in the direction orthogonal to the scanning direction 50 of the microlenses 2 a is constant for all the microlens arrays 2. In the scanning direction 50, one microlens array 2 is arranged, and the pitch of the microlenses 2a in the microlens array 2 is constant.

  Note that the microlens array 2 can also be arranged on the support plate 1 so as to be separated from each other in both the scanning direction 50 and the direction orthogonal to the scanning direction 50 as shown in FIG. In this case, when viewed in the scanning direction 50, the microlens array 2 can be provided so that the end portions thereof overlap each other. Therefore, the end portion of each microlens array 2 with respect to the direction orthogonal to the scanning direction 50. It is not necessary to shorten the distance between the microlens 2a and the edge of the microlens 2a so that it is less than ½ of the pitch of the microlens 2a, and the width of the end of each microlens array 2 can be made sufficiently large. Further, the holes 1a of the support plate 1 do not need to have a short mutual interval in the direction orthogonal to the scanning direction 50 as shown in FIG. 1 and 5, the microlens arrays 2 are arranged in a staggered manner in the direction orthogonal to the scanning direction 50, but the microlens arrays 2 are close to each other as shown in FIG. In this case, the microlens array 2 can be arranged in a straight line in the scanning direction 50.

  In the embodiment shown in FIG. 1, each microlens array 2b has, for example, two sides facing the scanning direction 50, one supported by two piezoelectric elements 3a and 3b, and the other by one piezoelectric element 3c. The microlens array 2c is supported by, for example, two sides facing the scanning direction 50, one supported by one piezoelectric element 3d and the other supported by two piezoelectric elements 3e and 3f. .

  As shown in FIGS. 2 and 3, holes 1a having a shape corresponding to the shape of the microlens array 2 are formed at the arrangement position of the microlens array 2 on the support plate 1 as described above. 2 is fitted in the hole 1a. In addition, the upper surface of the support plate 1 is cut out around the hole 1a to form a step 1b. The piezoelectric element 3 is arranged in the lower part of the paragraph 1b, that is, in the peripheral part of the hole 1a. ing. The microlens array 2 is formed with a flange portion 21 extending in the horizontal direction at an upper portion thereof, and the flange portion 21 is positioned at the step 1b around the hole 1a of the support plate 1.

  The base 31 of the piezoelectric element 3 is fixed to the lower portion of the step 1 b of the support plate 1, and the tip 32 is fixed to the lower surface of the flange portion 21 of the microlens array 2. The piezoelectric element 3 is connected to an appropriate control device (not shown) by a lead wire 4, and the piezoelectric element 3 is supplied with a drive voltage from the control device through the lead wire 4, and is shown in FIG. Deform as shown. That is, in FIG. 2, since the piezoelectric element 3 is not deformed, the optical axis of the microlens array 2 is oriented in the vertical direction (perpendicular to the surface of the support plate 1). The piezoelectric element 3 of the microlens array 2 is deformed so that the tip 32 thereof faces upward, whereby the microlens array 2 is oriented in a direction in which the optical axis is inclined with respect to the vertical direction. Thus, since the direction of the optical axis of the microlens array 2 can be adjusted by adjusting the voltage applied to the piezoelectric element, the support plate 1 has a portion with poor flatness, and is disposed at that location. When the optical axis of the microlens array 2 is not perpendicular to the substrate, the optical axis of the microlens array 2 can be made vertical by adjusting the voltage applied to the piezoelectric element 3. Needless to say, the support points by the piezoelectric element 3 are not limited to the above-described three points, and four or more points may be provided. In this case, it is necessary to regulate the deformation amounts of four or more piezoelectric elements.

  FIG. 6 is a schematic diagram showing the structure of each microlens 2 a constituting each microlens array 2. Each microlens 2a of each microlens array 2 has, for example, a four-lens configuration and a structure in which four microlens arrays 2-1, 2-2, 2-3, 2-4 are stacked. . Each microlens array 2-1 or the like is composed of two lenses. As a result, the exposure light once converges between the microlens array 2-2 and the microlens array 2-3, and forms an image on the substrate below the microlens array 2-4. A hexagonal field stop 12 is disposed between the microlens array 2-2 and the microlens array 2-3, and an aperture stop 11 is disposed between the microlens array 2-3 and the microlens array 2-4. Has been. The hexagonal field stop 12 and the aperture stop 11 are provided for each microlens 2a, and the exposure area on the substrate is shaped into six corners for each microlens 2a. For example, as shown in FIG. 7A, the hexagonal field stop 12 is formed as a hexagonal opening in the lens field area 10 of the microlens 2a, and the aperture stop 11 is formed as shown in FIG. As shown, a circular opening is formed in the lens visual field region 10 of the microlens 2a.

  FIG. 8 is a plan view showing an arrangement mode of each microlens 2 a in each microlens array 2. In FIG. 8, the arrangement of the microlenses 2a is shown as the position of the hexagonal field stop 12 of the microlenses 2a. As shown in FIG. 8, the microlenses 2 a are sequentially shifted slightly in the horizontal direction in the scanning direction 5. The hexagonal field stop 12 is divided into a central rectangular portion 12 a and triangular portions 12 b and 12 c on both sides when viewed in the scanning direction 5. Then, as shown in FIG. 8, regarding each column in the direction perpendicular to the scan direction 5, when viewing the three columns of the hexagonal field stop 12 in the scan direction 5, a specific hexagonal field stop in the first column The right triangular portion 12c of 12 overlaps with the triangular portion 12b on the left side of the hexagonal field stop 12 in the second row adjacent to the rear in the scanning direction, and the triangular portion 12b on the left side of the hexagonal aperture 12 in the first row has 3 These microlenses 2a are arranged so as to overlap the triangular portion 12c on the right side of the hexagonal field stop 12 in the row. In this manner, three rows of microlenses 2a are arranged as one set with respect to the scanning direction 5. That is, the fourth row of microlenses 2 a are arranged at the same position as the first row of microlenses 2 a in the direction perpendicular to the scan direction 5. At this time, assuming that the line segments (shown by broken lines in the figure) connecting the respective corners of the hexagon of the hexagonal field stop 12 in the scanning direction 5 are equidistant, for example, 0.03 mm, three rows of hexagons In the field stop 12, when the area of the triangular portion 12b of the two adjacent hexagonal field stops 12 and the area of the triangular portion 12c are added, the total area of the two triangular portions 12b and 12c overlapping in the scanning direction 5 is as follows. The area of the central rectangular portion 12a is the same. For this reason, when the substrate 1 is scanned by the three rows of microlenses 2a, it is exposed to a uniform amount of light in the entire area in the direction perpendicular to the scanning direction 5. Therefore, each microlens array 2 is arranged with microlenses 2a in an integer multiple of 3 with respect to the scanning direction 5, so that the substrate can expose a uniform amount of light over the entire area by one scan. Will receive. Note that the line segments (indicated by broken lines in the figure) that connect the respective corners of the hexagon of the hexagonal field stop 12 in the scanning direction 5 do not necessarily have to be equally spaced. For example, the width of the rectangular portion 12a at the center of the hexagonal field stop 12 may be different from the height of the triangular portions 12b and 12c.

  Next, the operation of the exposure apparatus configured as described above will be described. A plurality of microlens arrays 2 are installed on the support plate 1. At this time, as shown in FIG. 2, each microlens array 2 is supported by two piezoelectric elements 3 and one piezoelectric element 3, for example, on two sides opposed to the scanning direction 50. Then, exposure light is made incident on the plurality of microlens arrays 2 through the mask 6 to form an exposure pattern on the substrate 22, and the exposed pattern on the substrate is observed by means such as a camera or a microscope. When the support plate 1 is distorted, the exposure image of the specific microlens array 2 is deviated from a predetermined position, and the optical axis is deviated from a predetermined direction (for example, the vertical direction). Then, the applied voltage of the piezoelectric element 3 supporting the specific microlens array 2 is adjusted to adjust the optical axis of the specific microlens array 2 in the correct direction. At this time, the microlens array 2 is supported by the piezoelectric element 3 at three points, and the microlens array 2 is directed in an arbitrary direction by relatively adjusting the positions of the three points by the piezoelectric element 3. be able to. Therefore, the optical axis of the microlens array 2 can be adjusted in an arbitrary direction. In this way, the direction of the optical axis of the microlens array 2 arranged on the support plate 1 is adjusted in the same direction for all the microlens arrays 2 regardless of distortion factors such as the flatness of the support plate 1. A large area substrate by combining a plurality of microlens arrays 2 without using a heavy support plate, that is, using a light support plate. Can be exposed in a single process with a large-area mask. This adjustment of the optical axis of the microlens array is also effective in absorbing the deviation when the exposure target on the substrate is displaced.

  Note that the adjustment of the optical axis of the microlens array 2 by the piezoelectric elements is not necessarily performed for all the microlens arrays. The piezoelectric elements 3 are provided in some of the microlens arrays 2, For the microlens array 2 that can be provided and the optical axis can be adjusted, the optical axis is adjusted by adjusting the voltage applied to the piezoelectric element 3 so as to coincide with the optical axis of the microlens array 2 fixed to the support plate 1. May be.

  In the embodiment shown in FIGS. 2 and 3, the lower surface of the flange portion 21 of the microlens array 2 is supported by the tip 32 of the piezoelectric element 3, so that the height at which the flange portion 21 of the microlens array 2 is lifted is increased. By adjusting, the optical axis of the microlens array 2 is adjusted. However, when the gap between the side surface of the hole 1a of the support plate 1 and the side surface of the microlens array 2 is made larger and the size of the hole 1a is made larger than the flange portion 21, the tip 32 of the piezoelectric element 3 becomes the base portion. By making the piezoelectric element 3 deformable so as to be lower than 31, the support point of the flange portion 21 of the microlens array 2 can be lowered. Thereby, the freedom degree of adjustment of the optical axis of the micro lens array 2 further increases.

  Further, in the embodiment shown in FIGS. 2 and 3, one piezoelectric element 3 is set at each support point of the flange portion 21 of the microlens array 2, and this piezoelectric element 3 is moved up and down at each support point. The two piezoelectric elements can be fixed so as to sandwich the flange portion 21 at the support point from above and below. That is, the flange portion 21 is fixed to the two piezoelectric elements 3 on both the upper surface and the lower surface. Then, the two opposite piezoelectric elements 3 in the microlens array 2 are deformed so that the central portion of the microlens array 2 rises or the central portion descends, so that the microlens array 2 is not flat. Can be curved. For example, when the tip 32 of each piezoelectric element 2 arranged on two opposing sides in the microlens array 2 is deformed so as to rise upward, the center of the microlens array 2 rises more than the end. As a result of the deformation, the microlens array 2 is curved upward. Thereby, the space | interval of the optical axis of each micro lens 2a in the micro lens array 2 can be made smaller on a board | substrate. On the contrary, when the tip 32 of each piezoelectric element 3 arranged on the two opposite sides in the microlens array 2 is deformed in the descending direction, the central portion of the microlens array 2 is lowered from the end. The microlens array 2 is curved in a downwardly convex state. Thereby, the space | interval of the optical axis of each micro lens 2a in the micro lens array 2 can be enlarged on a board | substrate. Thus, by curving the microlens array 2, the interval between exposure positions on the substrate can be increased or decreased, and a similar process can be performed to change the magnification of the focusing lens of the exposure apparatus. It can be carried out. As described above, since the microlens 2a forms an erecting equal magnification, the magnification cannot be changed. For this reason, as described above, it is extremely beneficial that the magnification can be changed in a pseudo manner by curving the microlens array 2.

  As described above, after the optical axis adjustment of the microlens array 2 is completed, the substrate 22 is carried below the microlens array 2. Then, by moving the substrate 22 and the mask 6 in the scanning direction 50 and irradiating the mask 6 with the exposure light emitted from the exposure light source 20, the microlens array 2 and the mask 6 are relatively moved in the scanning direction. In other words, the exposure pattern formed on the entire area of the large-area mask 6 on the large-area substrate 22 is exposed with high accuracy by a single scan.

1, 5: Support plates 2, 2b, 2c: Micro lens array 2a: Micro lenses 2-1 to 2-4: (Configuration) Micro lens array 3: Piezoelectric element 6: Mask 6a: Transparent substrate 6b: Cr film 11: Aperture stop 12: Hexagon field stop 12a: Rectangular portion 12b, 12c: Triangle portion 20: Exposure light source 50: Scan direction

Claims (2)

An exposure light source;
A mask that blocks exposure light from the exposure light source by an exposure pattern;
A plurality of microlens arrays disposed between the substrate to be exposed and the mask , each having a plurality of microlenses arranged two-dimensionally;
A support plate on which the plurality of microlens arrays are disposed;
A piezoelectric element provided for at least one microlens array on the support plate;
Have
The plurality of microlens arrays are arranged such that the intervals of all the microlenses are the same in the direction orthogonal to the relative scanning direction between the substrate and the mask and the microlens array. ,
At least three of the piezoelectric elements are arranged for each microlens array provided with the piezoelectric elements, the base ends of the piezoelectric elements are fixed on the support plate, and the tips of the piezoelectric elements are fixed to the microlens array. Is supported by at least three points,
An exposure apparatus using a microlens array, wherein an optical axis of each microlens array can be adjusted by adjusting a voltage applied to the piezoelectric element. Before SL microlens exposure apparatus using a microlens array according to claim 1, characterized in that projecting the erect image of the exposure pattern of the mask on the substrate.

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