JP5874966B2 - Microlens array and bonding method thereof - Google Patents

Description

  The present invention relates to a microlens array used in an exposure apparatus and a bonding method for manufacturing the same, and more particularly to a microlens array in which a plurality of unit microlens arrays are superimposed and a bonding method thereof.

  Recently, an exposure apparatus that projects a mask pattern onto a substrate by a microlens array has been used (Patent Document 1). FIG. 7 is a schematic view showing an exposure apparatus using a microlens array. A mask 3 on which a pattern to be exposed on the substrate 1 is formed is disposed above the substrate 1 to be exposed with an appropriate length from the substrate 1. A microlens array 2 in which microlenses 2a are two-dimensionally arranged is disposed between the substrate 1 and the mask 3, and exposure light is irradiated onto the mask 3 from above the mask 3, and the mask 3 is projected onto the substrate 1 by the microlens array 2, and the pattern formed on the mask 3 is transferred to a resist or the like on the substrate surface as an erecting equal-magnification image by the microlens array 2. .

  4 shows a microlens array 2 used in the exposure apparatus, FIG. 5A shows a hexagonal field stop 12, and FIG. 5B shows a schematic view showing a circular stop 11. As shown in FIG. 4, the microlens array 2 has, for example, a four-lens eight-lens configuration, and a structure in which four unit microlens arrays 2-1, 2-2, 2-3, 2-4 are stacked. Have The microlenses of each of the unit microlens arrays 2-1 to 2-4 are composed of an optical system expressed by two convex lenses. As a result, the exposure light once converges between the unit microlens array 2-2 and the unit microlens array 2-3, and further forms an image on the substrate below the unit microlens array 2-4. That is, an inverted equal magnification image of the mask 3 is formed between the unit micro lens array 2-2 and the unit micro lens array 2-3, and an erect equal magnification image of the mask 3 is formed on the substrate. Image. A polygonal field stop (for example, a hexagonal field stop 12) is disposed between the unit microlens array 2-2 and the unit microlens array 2-3, and the unit microlens array 2-3 and the unit microlens array 2- A circular diaphragm 11 is arranged between the four. The circular diaphragm 11 defines the NA (numerical aperture) of each microlens, and the hexagonal field diaphragm 12 narrows the field to a hexagonal shape near the imaging position. The hexagonal field stop 12 and the circular stop 11 are provided for each microlens. For each microlens, the light transmission area of the microlens is shaped into a circle by the circular stop 11 and exposure light is exposed on the substrate. The region is shaped into a hexagon by a hexagonal field stop 12. For example, as shown in FIG. 5, the hexagonal field stop 12 is formed as a hexagonal opening in the lens opening 10 of the microlens. Therefore, if the scanning of the exposure light transmitted through the microlens array 2 by the hexagonal field stop 12 is stopped, one microlens surrounds the hexagonal shape shown in FIG. Irradiate only the affected area.

  In the exposure apparatus using this microlens array, the substrate 1 and the mask 3 are fixed, and the microlens 2 and the light source (not shown) move in the scanning direction S in synchronization with each other. For example, the resist film on the surface of the substrate 1 is exposed to the pattern of the mask 3 by scanning, or the microlens array 2 and the light source are fixed, and the substrate 1 and the mask 3 move in the scanning direction S in synchronization with each other. Thus, the resist film on the surface of the substrate 1 is scan-exposed with the pattern of the mask 3.

  At this time, on the surface of the substrate 1, exposure light is instantaneously applied to the hexagonal portion of the hexagonal field stop 12 of each microlens as shown in FIG. As shown in FIG. 6, the micro lenses are arranged side by side in a direction perpendicular to the scan direction S, and the micro lens rows adjacent to the scan direction S are related to the micro lens rows arranged in the direction perpendicular to the scan direction S. Are slightly shifted in the direction perpendicular to the scanning direction S. That is, the hexagonal field stop 12 of the microlens has a hexagonal shape, and is composed of a left triangle portion 12b, an intermediate rectangle portion 12a, and a right triangle portion 12c with respect to a direction perpendicular to the scanning direction S. ing. A plurality of microlens rows are arranged in the scan direction S so that the triangle portion 12b on the left side of the microlens row and the triangle portion 12c on the right side of the microlens row adjacent to the scan direction S overlap in the scan direction S. Has been. Therefore, the microlenses 2a are arranged on a straight line in the direction perpendicular to the scanning direction S and are slightly shifted in the scanning direction S. These microlens rows are arranged so as to form one group of three rows in the scanning direction S, and the fourth microlens row is arranged at the same position as the first microlens row. ing. That is, the first and fourth microlens rows have the same position in the direction perpendicular to the scanning direction S of the microlens 2a.

  When the microlens array 2 and the light source, the substrate 1 and the mask 3 move relative to each other in the scanning direction S, first, on the substrate 1, the microarrays in the first row are related to the direction perpendicular to the scanning direction S. The region that receives the right triangular portion 12c of the hexagonal field stop of the lens row is then passed through the left triangular portion 12b of the hexagonal field stop of the second microlens row, and the third microlens row. Then there is no passage through the opening. On the other hand, the area that receives the rectangular portion 12a of the hexagonal field stop of the first microlens array does not pass through the opening in the second and third microlens arrays. Further, the region that receives the left triangular portion 12b of the hexagonal field stop of the first microlens row does not pass through the opening in the second microlens row, and then the third microlens. Passes through the right triangle portion 12c of the hexagonal field stop of the row. In this way, during scanning, the area on the substrate 1 is subjected to the passage of the two triangular portions 12b and 12c of the hexagonal field stop 12 each time three micro lens rows pass or one The rectangular portion 12a is passed through. Since the opening areas of the triangular portions 12b and 12c are ½ of the opening area of the rectangular portion 12a, the light is exposed with a uniform amount of light in the scanning direction S every time three microlens rows pass. In the fourth microlens array, since the microlenses are arranged at the same position as the first microlens array in the direction perpendicular to the scanning direction S, the third microlens array is the same as the third array in one group. The exposure is repeated. Accordingly, as the microlens array 2, 3n (n is a natural number) microlens rows are provided in the scanning direction S, and the substrate 1 is scanned over the entire scan region by scanning the 3n microlens rows. , Receive uniform exposure with uniform light quantity. As a result, the microlens array 2 and the light source move relative to the substrate 1 and the mask 3 in the scanning direction S, so that the pattern formed on the mask 3 is exposed on the substrate 1. In this way, an erecting equal-magnification image of the mask pattern of the mask 3 is transferred to the substrate 1 by the microlens array 2.

JP 2010-79292 A

  When the microlens array configured as described above is used for high-definition exposure, a plurality of unit microlens arrays 2-1, 2-2, 2-3, 2-4 are used as the light of each microlens It is necessary to match the axes with high accuracy and paste them together. However, conventionally, the optical axis of each microlens of the plurality of unit microlens arrays cannot be controlled with high accuracy. Although it is conceivable that the alignment of the unit microlens arrays is achieved through the alignment mark by forming an alignment mark on the edge of each unit microlens array excluding the arrangement position of the microlens. In the alignment mark formation region, the exposure light is transmitted through the microlens array 2 and the lower substrate 1 is exposed.

  The present invention has been made in view of such a problem, and when a microlens array is manufactured by stacking and bonding unit microlens arrays, each unit microlens array is aligned with high accuracy. An object of the present invention is to provide a microlens array suitable for high-definition exposure and a method for bonding the same.

The microlens array according to the present invention is a microlens array formed by laminating a plurality of unit microlens arrays each having a plurality of microlenses arranged two-dimensionally in the thickness direction.
Each unit microlens array has a lens region in which the microlens is arranged, and an alignment region in which an alignment mark at the edge of the lens region is formed,
On the upper and lower surfaces of each unit microlens array in the alignment region, a light shielding film and an opening lacking the light shielding film are provided,
The alignment mark is formed in the opening on the facing surface between the unit microlens arrays, and the alignment mark pairs are arranged at different positions in plan view ,
An alignment mark provided on the lower surface of the unit microlens array at the upper position and an alignment mark provided on the upper surface of the unit microlens array at the lower position, and the microlens array at the upper position and the microlens array at the lower position. Configure alignment mark pairs for alignment,
In plan view, there is a light shielding film on the lower surface of the lowest unit microlens array below the opening where the light shielding film on the upper surface of the uppermost unit microlens array is missing. It is characterized by being.

Furthermore, the method of laminating a microlens array according to the present invention is a microlens constructed by laminating a plurality of unit microlens arrays each having a plurality of microlenses arranged two-dimensionally in the thickness direction. In the manufacturing method of the lens array,
Each unit microlens array has a lens region in which the microlens is arranged, and an alignment region in which an alignment mark at the edge of the lens region is formed,
On the upper and lower surfaces of each unit microlens array in the alignment region, a light shielding film and an opening lacking the light shielding film are provided,
The alignment mark is formed in the opening in the facing surface between the unit microlens arrays,
An alignment mark provided on the lower surface of the unit microlens array at the upper position and an alignment mark provided on the upper surface of the unit microlens array at the lower position, and the microlens array at the upper position and the microlens array at the lower position. Configure alignment mark pairs for alignment,
In plan view, there is a light shielding film on the lower surface of the lowest unit microlens array below the opening where the light shielding film on the upper surface of the uppermost unit microlens array is missing. Is what has been
First, an alignment mark pair of an alignment mark provided on the lower surface of the upper unit microlens array and an alignment mark provided on the upper surface of the lower unit microlens array for every two unit microlens arrays, A first step of aligning these unit microlens arrays by irradiating illumination light with an epi-illumination camera and detecting the reflected light, and bonding them together,
Next, two pairs of unit microlens arrays are arranged in pairs, and an alignment mark provided on the lower surface of the unit microlens array below the pair of unit microlens arrays at the upper position and a pair of lower positions. The pair of alignment marks with the alignment mark provided on the upper surface of the unit microlens array above the unit microlens array is irradiated with illumination light by an epi-illumination camera, and the reflected light is detected. A second step of aligning the unit microlens arrays and bonding them together;
Thereafter, in the same manner, if necessary, one group of unit microlens arrays is provided on the lower surface of the unit microlens array below the group of unit microlens arrays at the upper position for every two groups. The reflected light is detected by irradiating the alignment mark pair of the mark and the alignment mark provided on the upper surface of the unit microlens array above the group of unit microlens arrays in the lower position with an incident illumination camera. A third step of aligning these one group of unit microlens arrays and bonding them together;
Have
The alignment mark pair used in the first step, the alignment mark pair used in the second step, and the alignment mark pair used in the third step are arranged at different positions in plan view. And
The alignment mark pair to be aligned last is an area where, in plan view, the opening where the light shielding film on the upper surface of the uppermost unit microlens array is missing and the light shielding film on the lower surface of the lowermost unit microlens array overlap. It is characterized by being arranged in.

Furthermore, another microlens array bonding method according to the present invention is formed by laminating a plurality of unit microlens arrays each having a plurality of microlenses arranged two-dimensionally in the thickness direction. In the manufacturing method of the manufactured microlens array,
Each unit microlens array has a lens region in which the microlens is arranged, and an alignment region in which an alignment mark at the edge of the lens region is formed,
On the upper and lower surfaces of each unit microlens array in the alignment region, a light shielding film and an opening lacking the light shielding film are provided,
The alignment mark is formed in the opening in the facing surface between the unit microlens arrays,
An alignment mark provided on the lower surface of the unit microlens array at the upper position and an alignment mark provided on the upper surface of the unit microlens array at the lower position, and the microlens array at the upper position and the microlens array at the lower position. Alignment mark pairs for alignment are configured, and each alignment mark pair is arranged at a different position in plan view.
First, the illumination light is irradiated to the lowest unit microlens array and the upper unit microlens array by an epi-illumination camera, and from the alignment mark pairs formed on the opposing surfaces of these unit microlens arrays. A first step of detecting reflected light, aligning the unit microlens arrays, and bonding the unit microlens arrays together;
Similarly, a second step of aligning two unit microlens arrays in order from the bottom using an alignment mark pair between the two and bonding the unit microlens arrays to each other,
Similarly, two unit microlens arrays adjacent to each other in the upper and lower sides are aligned using an alignment mark pair between them, and bonded to each other, and finally bonded to the uppermost unit microlens array. A third step;
Have
A plurality of alignment mark pairs in order from the bottom are arranged in a position aligned with the opening formed on the lower surface of the lowest unit microlens array in plan view,
Each pair of alignment marks is arranged at a position that aligns with the opening formed on the upper surface of the unit microlens array in the upper position where the alignment mark pair is formed in plan view,
The light-shielding film is arranged so that there is no region where all the openings overlap in a plan view.

  In the present invention, there is a light shielding film on the lower surface of the lowermost unit microlens array below the opening in which the light shielding film on the upper surface of the uppermost unit microlens array is missing in plan view. Since the entire surface is shielded from light, the entire alignment region is shielded from light so that exposure light does not pass through the alignment region of the microlens array and expose the substrate.

  In addition, the alignment mark pair for the last alignment has a light shielding film on the lower surface of the lowermost unit microlens array below the alignment mark pair. Since it is located in the middle of the lens array, even if there is a light shielding film of the lowest unit micro lens array below this alignment mark pair, when reflected light from the alignment mark is detected by the epi-illumination camera The contrast does not decrease, and a clear alignment mark image can be obtained. In other words, if there is a light-shielding film below the alignment mark pair to be aligned, the reflected light from the alignment mark and the reflected light from the light-shielding film are incident on the epi-illumination camera with the same amount of light. This reduces the contrast of the image. However, in the present invention, the last alignment mark pair to be aligned is located in the middle of the plurality of unit microlens arrays, so that an image can be detected with sufficiently high contrast.

It is sectional drawing which shows the microlens array which concerns on embodiment of this invention. It is a figure which similarly shows the alignment mark. It is a top view of a unit micro lens array. It is sectional drawing which shows the unit micro lens array which comprises a micro lens array. It is a top view which shows a hexagonal field stop and a circular stop. It is a schematic diagram which shows arrangement | positioning of a micro lens. It is a schematic diagram which shows the exposure apparatus which uses a micro lens array.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 shows a microlens array according to an embodiment of the present invention. The microlens array of the present embodiment is composed of eight unit microlens arrays 2-1 to 2-8. In each unit microlens array, as shown in FIG. 3, a plurality of microlenses 2a are two-dimensionally arranged, and the arrangement of these microlenses 2a is the same as the conventional microlens shown in FIG. . Further, the structure of each unit microlens array is the same as that of the conventional microlens array shown in FIG. 4, but in the case of the eight-sheet configuration of FIG. 1, microlenses are formed only on the upper surface of each glass substrate. In the lens region where the microlenses are formed, a light shielding film 1a made of a Cr film is formed in the gap between the microlenses 2a.

  An alignment region 20 in which an alignment mark 23 is formed is provided at the edge of the lens region in which the micro lens 2a is formed. In this alignment region 20, a light shielding film 20a such as a Cr film is formed. ing. A suction region 25 is provided on the further edge side of the alignment region 20. The suction region 25 is a region for feeding a unit microlens array to the bonding apparatus by sucking a conveyance member (not shown) by vacuum suction or the like.

  As shown in FIG. 1, a light shielding film 20a such as a Cr film is formed in the alignment region 20 on the upper surface of the uppermost unit microlens array 2-1. A light shielding film 20b such as a Cr film is formed in the alignment region 20 on the lower surface of the lowest unit microlens array 2-8. Similarly, on the lower surface of the uppermost unit microlens array 2-1, the upper surface of the lowermost unit microlens array 2-8, and the upper and lower surfaces of the other unit microlens arrays 2-2 to 2-7, A light shielding film 20c such as a Cr film is formed. In each of the light shielding films 20c, a relatively wide area at the center of the unit microlens array is missing, and an opening 24 is formed. The size and position of the opening 24 are the same for all the unit microlens arrays 2-1 to 2-8. On the other hand, a relatively small opening 21 is formed in the light-shielding film 20a on the upper surface of the uppermost unit microlens array 2-1. . In addition, in the light shielding film 20b on the lower surface of the lowest unit microlens array 2-8, a part of the right side of the unit microlens array 2-8 is missing and a relatively small opening 22 is formed. . In plan view, the light shielding film 20b on the lower surface of the lowest unit microlens array 2-8 is present below the opening 21, and the uppermost unit microlens is above the opening 22. There is a light shielding film 20a on the upper surface of the array 2-1. As a result, the entire surface of the unit microlens array is shielded from light by the light shielding films 20a and 20b in plan view.

  A pair of alignment marks 23-1 is provided on the lower surface of the unit microlens array 2-1 and the upper surface of the unit microlens array 2-2, and the lower surface of the unit microlens array 2-2 and the unit microlens array 2- 3 is provided with a pair of alignment marks 23-2, and a pair of alignment marks 23-3 is provided on the lower surface of the unit microlens array 2-3 and the upper surface of the unit microlens array 2-4. A pair of alignment marks 23-4 is provided on the lower surface of the unit microlens array 2-4 and the upper surface of the unit microlens array 2-5, and the lower surface of the unit microlens array 2-5 and the unit microlens array are provided. A pair of alignment marks 23-5 is provided on the upper surface of 2-6, and the unit microlens array 2 6 and the upper surface of the unit microlens array 2-7 are provided with a pair of alignment marks 23-6. The alignment is provided on the lower surface of the unit microlens array 2-7 and the upper surface of the unit microlens array 2-8. A pair of marks 23-7 is provided. These pairs of alignment marks 23 are arranged at positions where they do not overlap in a plan view. For example, the pairs of alignment marks 23 are sequentially arranged adjacent to each other in plan view. The opening 24 has the seven pairs of alignment marks 23 (23-1, 23-2, 23-3, 23-4, 23-5, 23-6, 23-7) in the opening 24. Each of them has a size for arranging so as not to overlap. On the other hand, all of the openings 21 of the light shielding film 20a on the upper surface of the uppermost unit microlens array 2-1 have the alignment marks 23-1, 23-2, 23-3, 23-4 in the plan view. It has a size that fits inside. Further, the opening 22 of the light shielding film 20b on the lower surface of the lowest unit microlens array 2-8 has such a size that the alignment marks 23-6 and 23-7 are all within the opening 22 in a plan view. Have.

  The alignment mark 23 is a pair of the mark 23a formed on the lower surface of the unit microlens array shown in FIG. 2A and the marks 23b and 23c formed on the upper surface of the unit microlens array shown in FIG. Consists of. The mark 23a is a portion where a light shielding film such as a Cr film is missing in a square shape. The mark 23b is also a portion where a light shielding film such as a Cr film is missing in a square shape, but is larger than the mark 23a. The mark 23c is a square light-shielding film such as a Cr film formed at the center of the mark 23b. When the alignment marks 23 are matched with each other, the mark 23c is positioned at the center of the mark 23a as shown in FIG. The alignment mark 23 is detected using an epi-illumination camera. The epi-illumination camera irradiates illumination light and makes reflected light reflected by a mark coaxial with the optical axis of the illumination light to detect an object image.

  Next, the operation of the microlens array and the bonding method configured as described above will be described. First, as shown in FIG. 1, in the alignment region 20, the uppermost unit microlens array 2-1 having a small opening 21 on the upper surface and the lowermost unit microlens array 2 having a small opening 22 on the lower surface. -8 and unit microlens arrays 2-2 to 2-7 having an opening 24 having an intermediate size on the upper and lower surfaces are prepared.

  Then, the transfer device installs the unit microlens arrays 2-1 and 2-2 in the bonding device, and the illumination light of the epi-illumination camera is applied to the unit microlens array 2-1 from above the unit microlens array 2-1. The unit microlens arrays 2-1 and 2-2 are irradiated using the alignment marks 23-1 between the unit microlens arrays 2-1 and 2-2. After aligning and aligning, the adhesive is injected between the edges of the unit microlens arrays 2-1 and 2-2, and the adhesive is solidified by irradiation with ultraviolet light. 2-1 and 2-2 are pasted together. Similarly, the unit microlens arrays 2-3 and 2-4 are aligned by the epi-illumination camera using the alignment mark 23-3, and the unit microlens arrays 2-3 and 2-4 are pasted with an adhesive. Match. Similarly, the unit micro lens arrays 2-5 and 2-6 and the unit micro lens arrays 2-7 and 2-8 are aligned with each other using the alignment marks 23-5 and 23-7, respectively. After taking, stick together.

  Next, the pair of unit microlens arrays 2-1 and 2-2 already bonded together and the pair of unit microlens arrays 2-3 and 2-4 are installed in the bonding apparatus by the transport device, Using the alignment mark 23-2 between the unit microlens arrays 2-2 and 2-3, the images of the marks 23a, 23b and 23c are detected and aligned by an epi-illumination camera, and the unit is formed by an adhesive. The microlens arrays 2-2 and 2-3 are bonded together. Thereby, the bonding of the unit microlens arrays 2-1, 2-2, 2-3, 2-4 is completed. Further, the pair of unit microlens arrays 2-5, 2-6 and the pair of unit microlens arrays 2-7, 2-8 that have already been bonded together are installed in the bonding apparatus by the transport device, and the unit Using the alignment mark 23-6 between the microlens arrays 2-6 and 2-7, the images of the marks 23a, 23b, and 23c are detected and aligned by an epi-illumination camera, and the unit micro is formed by an adhesive. The lens arrays 2-6 and 2-7 are bonded together.

  Next, the four unit microlens arrays 2-1 to 2-4 that have been bonded together and the four unit microlens arrays 2-5 to 2-8 that have been bonded together are combined into a bonding apparatus by a transport device. The four unit microlens arrays are aligned using an alignment mark 23-4 between the unit microlens array 2-4 and the unit microlens array 2-5, and the unit microlens is aligned with an adhesive. The lens array 2-4 and the unit micro lens array 2-5 are bonded and bonded together. In this way, all the eight unit microlens arrays 2-1 to 2-8 are bonded to each other. At the time of bonding, the alignment marks 23 are used to align the unit microlens arrays, and the unit microlens arrays are joined together, so that the optical axes of the microlenses all coincide with each other with high accuracy. It becomes.

  In this case, alignment marks 23-1, 23 between the unit microlens arrays 2-1, 2-2, between the unit microlens arrays 2-3, 2-4, and between the unit microlens arrays 2-7, 2-8. In the detection of the images of −3 and 23-7, the illumination light from the epi-illumination camera does not have the light shielding films 20b and 20c in the vicinity below the alignment mark 23, so that only the reflected light from the alignment mark 23 is present. Incident on the epi-illumination camera. Therefore, the epi-camera detects the reflected light from the alignment mark 23 with high contrast. Therefore, the image of the alignment mark 23 (the image of the mark 23c) can be detected clearly, and the alignment accuracy is high. Similarly, when detecting the images of the alignment marks 23-2 and 23-6 between the unit microlens arrays 2-2 and 2-3 and between the unit microlens arrays 2-6 and 2-7, the alignment mark 23 is similarly detected. Since the light shielding films 20b and 20c do not exist in the vicinity below the alignment marks 23-2 and 23-6, the alignment marks 23-2 and 23-6 can be detected with high contrast. On the other hand, when detecting the alignment mark 23-5 between the unit microlens array 2-5 and the unit microlens array 2-6, the light shielding film 20b exists below the alignment mark 23-5. Since the distance between -5 and the light shielding film 20b on the lower surface of the lowest unit microlens array 2-8 is large, the amount of light reflected from the light shielding film 20b is incident on the epi-illumination camera is very small. Similarly, in the detection of the alignment mark 23-4 between the unit microlens array 2-4 and the unit microlens array 2-5, below the lowermost unit microlens array 2-8, Although the light shielding film 20b exists, similarly, since the distance between the alignment mark 23-4 and the light shielding film 20b is large, the amount of light reflected from the light shielding film 20b is incident on the epi-illumination camera is extremely small. Therefore, the reflected light from these alignment marks 23-4 can also be detected with high contrast.

  The obtained microlens array has the entire light-shielding film 20a on the upper surface of the uppermost microlens array 2-1 and the light-shielding film 20b on the lower surface of the lowermost microlens array 2-8. Since the region is shielded from light, the exposure light does not expose the substrate through the exposure region 20 during exposure. That is, since the light shielding film 20b exists below the opening 21 of the light shielding film 20a and the light shielding film 20a exists above the opening 22 of the light shielding film 20b, the exposure light passes through these alignment regions 20. There is no end to it.

  The position of the right end of the opening 21 is located to the left of the position of the left end of the opening 22 in plan view, and the light shielding film 20a and the light shielding film 20b overlap each other in plan view. This is a light-shielding film overlapping region for shielding the spread of the exposure light because the exposure light normally has a spread of ± 2 to 3 °.

  In this way, according to the number of unit microlens arrays, such as aligning two unit microlens arrays, then aligning two pairs, then aligning four pairs, The alignment is sequentially performed, and the final alignment is completed to complete the microlens array. Even if there is a light-shielding film on the lower surface of the lowest-order unit microlens array below the alignment mark to be aligned last, the distance between this last alignment mark and the lowest-order light-shielding film is large. The influence on the contrast of the reflected light from the lower light shielding film is extremely small. On the other hand, by providing a light-shielding film below the alignment mark for the final alignment, the entire alignment region can be shielded in plan view, and exposure light passes through the alignment region to expose the substrate. This can be prevented.

  Needless to say, the present invention is not limited to the above embodiment. For example, when there are four unit microlens arrays, three pairs of alignment marks are provided between them, but below the upper alignment mark 23-1 and the center alignment mark 23-2, The light shielding film on the lower surface of the lower unit microlens array 2-4 is positioned, and the light shielding film on the lower surface of the lowest unit microlens array 2-4 has an opening at a position below the lower alignment mark 23-3. As for the light shielding film on the upper surface of the uppermost unit microlens array 2-1, the upper position of the upper alignment mark 23-1 and the upper alignment mark 23-2 may be an opening. The other light-shielding films are provided with openings so as not to shield all three alignment marks.

  In the embodiment shown in FIG. 1, all the alignment marks 23-1 and the like are provided at different positions in plan view. In this embodiment, two unit microlens arrays are used in the first step. In the second step, a pair of unit microlens arrays are bonded together in the second step, and in the third step, one group of unit microlens arrays are bonded together in the third step. The position of the alignment mark pair may be different from each other in the first step, the second step, and the third step. That is, each pair of the alignment marks 23-1, 23-3, 23-5, and 23-7 in FIG. 1 may be provided at the same position in plan view. The pair of alignment marks 23-2 and 23-6 may also be provided at the same position in plan view. After all, if alignment marks 23-1, 23-3, 23-5, 23-7, alignment marks 23-2, 23-6, and alignment mark 23-4 are provided at different positions in plan view. Each pair of alignment marks can be observed by an epi-illumination camera from above.

  Further, in FIG. 1, the lowest unit microlens array 2-8 and the unit microlens array 2-7 thereabove are aligned and bonded together, and then the unit microlens array 2-7 and the upper unit microlens array 2-7 are bonded together. The unit microlens array 2-6 is aligned and bonded, and then the unit microlens array 2-6 and the unit microlens array 2-5 are aligned and bonded together. Each unit microlens array can also be bonded together in the process of aligning and bonding the two unit microlens arrays in order. In this case, in order to illuminate the alignment mark pair by the epi-illumination camera, alignment is made in plan view with the opening on the upper surface of the unit microlens array at the upper position of the two unit microlens arrays to be aligned. Thus, it is necessary that the alignment mark pair is arranged. Further, in order to prevent exposure light from passing through the alignment region and exposing the lower substrate during exposure, all the openings of the unit microlens arrays that are finally bonded overlap in plan view. It is necessary that the light shielding film is disposed so that such a region does not exist.

  According to the present invention, the stacked unit microlens arrays can be aligned with high accuracy, and the transmission of exposure light can be prevented, contributing to the manufacture of a high-performance microlens array.

1: Substrate 2: Microlens array 2a: Microlens 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, 2-8: Unit microlens array 3: Mask 10: Aperture 10a: Light shielding film 11: Circular diaphragm 12: Hexagonal field diaphragm 20: Alignment regions 20a, 20b, 20c: Light shielding films 21, 22, 24: Openings 23, 23-1, 23-2, 23- 4, 23-5, 23-6, 23-7: Alignment mark

Claims (3)

In a microlens array configured by laminating a plurality of unit microlens arrays configured by two-dimensionally arranging a plurality of microlenses in the thickness direction,
Each unit microlens array has a lens region in which the microlens is arranged, and an alignment region in which an alignment mark at the edge of the lens region is formed,
On the upper and lower surfaces of each unit microlens array in the alignment region, a light shielding film and an opening lacking the light shielding film are provided,
The alignment mark is formed in the opening on the facing surface between the unit microlens arrays, and the alignment mark pairs are arranged at different positions in plan view ,
An alignment mark provided on the lower surface of the unit microlens array at the upper position and an alignment mark provided on the upper surface of the unit microlens array at the lower position, and the microlens array at the upper position and the microlens array at the lower position. Configure alignment mark pairs for alignment,
In plan view, there is a light shielding film on the lower surface of the lowest unit microlens array below the opening where the light shielding film on the upper surface of the uppermost unit microlens array is missing. A microlens array characterized by being made. In a manufacturing method of a microlens array configured by laminating a plurality of unit microlens arrays configured by two-dimensionally arranging a plurality of microlenses in the thickness direction,
Each unit microlens array has a lens region in which the microlens is arranged, and an alignment region in which an alignment mark at the edge of the lens region is formed,
On the upper and lower surfaces of each unit microlens array in the alignment region, a light shielding film and an opening lacking the light shielding film are provided,
The alignment mark is formed in the opening in the facing surface between the unit microlens arrays,
An alignment mark provided on the lower surface of the unit microlens array at the upper position and an alignment mark provided on the upper surface of the unit microlens array at the lower position, and the microlens array at the upper position and the microlens array at the lower position. Configure alignment mark pairs for alignment,
In plan view, there is a light shielding film on the lower surface of the lowest unit microlens array below the opening where the light shielding film on the upper surface of the uppermost unit microlens array is missing. Is what has been
First, an alignment mark pair of an alignment mark provided on the lower surface of the upper unit microlens array and an alignment mark provided on the upper surface of the lower unit microlens array for every two unit microlens arrays, A first step of aligning these unit microlens arrays by irradiating illumination light with an epi-illumination camera and detecting the reflected light, and bonding them together,
Next, two pairs of unit microlens arrays are arranged in pairs, and an alignment mark provided on the lower surface of the unit microlens array below the pair of unit microlens arrays at the upper position and a pair of lower positions. The pair of alignment marks with the alignment mark provided on the upper surface of the unit microlens array above the unit microlens array is irradiated with illumination light by an epi-illumination camera, and the reflected light is detected. A second step of aligning the unit microlens arrays and bonding them together;
Thereafter, in the same manner, if necessary, one group of unit microlens arrays is provided on the lower surface of the unit microlens array below the group of unit microlens arrays at the upper position for every two groups. The reflected light is detected by irradiating the alignment mark pair of the mark and the alignment mark provided on the upper surface of the unit microlens array above the group of unit microlens arrays in the lower position with an incident illumination camera. A third step of aligning these one group of unit microlens arrays and bonding them together;
Have
The alignment mark pair used in the first step, the alignment mark pair used in the second step, and the alignment mark pair used in the third step are arranged at different positions in plan view. And
The alignment mark pair to be aligned last is an area where, in plan view, the opening where the light shielding film on the upper surface of the uppermost unit microlens array is missing and the light shielding film on the lower surface of the lowermost unit microlens array overlap. A method for laminating a microlens array, wherein the microlens array is disposed on the substrate. In a manufacturing method of a microlens array configured by laminating a plurality of unit microlens arrays configured by two-dimensionally arranging a plurality of microlenses in the thickness direction,
Each unit microlens array has a lens region in which the microlens is arranged, and an alignment region in which an alignment mark at the edge of the lens region is formed,
On the upper and lower surfaces of each unit microlens array in the alignment region, a light shielding film and an opening lacking the light shielding film are provided,
The alignment mark is formed in the opening in the facing surface between the unit microlens arrays,
An alignment mark provided on the lower surface of the unit microlens array at the upper position and an alignment mark provided on the upper surface of the unit microlens array at the lower position, and the microlens array at the upper position and the microlens array at the lower position. Alignment mark pairs for alignment are configured, and each alignment mark pair is arranged at a different position in plan view.
First, the illumination light is irradiated to the lowest unit microlens array and the upper unit microlens array by an epi-illumination camera, and from the alignment mark pairs formed on the opposing surfaces of these unit microlens arrays. A first step of detecting reflected light, aligning the unit microlens arrays, and bonding the unit microlens arrays together;
Similarly, a second step of aligning two unit microlens arrays in order from the bottom using an alignment mark pair between the two and bonding the unit microlens arrays to each other,
Similarly, two unit microlens arrays adjacent to each other in the upper and lower sides are aligned using an alignment mark pair between them, and bonded to each other, and finally bonded to the uppermost unit microlens array. A third step;
Have
A plurality of alignment mark pairs in order from the bottom are arranged in a position aligned with the opening formed on the lower surface of the lowest unit microlens array in plan view,
Each pair of alignment marks is arranged at a position that aligns with the opening formed on the upper surface of the unit microlens array in the upper position where the alignment mark pair is formed in plan view,
A method of attaching a microlens array, wherein a light shielding film is disposed so that there is no region where all the openings overlap in a plan view.

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