JP2004126360A - Microlens array and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microlens array which can be coupled with an optical fiber array with ease and precision, and to provide a method for manufacturing the same. <P>SOLUTION: The microlens array LA is provided with a quartz substrate 10 and a plated metallic connection plate 20 to be fitted to the substrate. On one main surface of the substrate 10, lenses L<SB>1</SB>-L<SB>5</SB>and plated metallic fitting pins 12, 14 are formed. The connection plate 20 is provided with a light transmission window 22 allowing transmission light of the lenses L<SB>1</SB>-L<SB>5</SB>to pass through, and fitting holes 24, 26 and guide pin through-holes 28, 30 are provided in such a manner that the diameter is increased from one main surface toward the other main surface. The microlens array LA is connected to the optical fiber array by inserting the guide pins 32, 34 into the through-holes 28, 30 at the end face of the optical fiber array in the state that the fitting pins 12, 14 are fitted to the fitting holes 24, 26 and the coupling plate 20 is fitted to the substrate 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a microlens array suitable for use in connection with an optical component such as an optical fiber array, and a method of manufacturing the microlens array.
[0002]
[Prior art]
Conventionally, as a microlens array, the one shown in FIG.
For example,
FIGS. 28 to 30 show a method of manufacturing this microlens array.
[0003]
In the step of FIG. 28, after a quartz glass layer 4 having a thickness of 50 μm is formed on one main surface of a silicon substrate 3 having a thickness of 500 μm, spherical convex portions are formed on the quartz glass layer 4 in accordance with a desired lens pattern. As described above, resist layers 5a to 5c are formed by photolithography and heat treatment.
[0004]
In the step of FIG. 29, the resist patterns 5a to 5c and the quartz glass layer 4 are etched by RIE (Reactive Ion Etching) to transfer the lens patterns of the resist layers 5a to 5c onto the upper surface of the quartz glass layer 4. Thus, convex lenses 4a to 4c corresponding to the resist layers 5a to 5c, respectively, are formed. The diameter of each convex lens can be 60 μm. Thereafter, a resist layer 6 having holes 6a to 6c for forming connection holes is formed on the other main surface of the substrate 3 by photolithography.
[0005]
In the step of FIG. 30, connection holes 3a to 3c are formed in the silicon substrate 3 by dry etching using the resist layer 6 as a mask so as to face the convex lenses 4a to 4c, respectively. In each connection hole, the depth can be 500 μm and the diameter can be 125 μm (corresponding to the diameter of the optical fiber).
[0006]
FIG. 31 shows a state in which the optical fiber 7 is inserted into the connection hole 3a in the microlens array of FIG. 30. The depth of the connection hole 3a is twice or more the diameter of the connection hole 3a. Is securely held by the connection hole 3a. Further, the convex lens 4a and the connection hole 3a are arranged such that the central axis of the convex lens 4a coincides with the central axis of the connection hole 3a, and the focal length of the convex lens 4a coincides with the distance from the top of the convex lens 4a to the bottom surface of the connection hole 3a. It is theoretically possible to focus the convex lens 4a at the center of the end face of the optical fiber 7 by inserting the optical fiber 7 into the connection hole 3a such that the tip of the optical fiber 7 contacts the bottom surface of the connection hole 3a. It is possible.
[0007]
[Patent Document 1]
JP-A-9-90162
[0008]
[Problems to be solved by the invention]
According to the above-described prior art, it is practically difficult to form the connection hole 3a so as to be adapted to, for example, the central axis or the focal length of the convex lens 4a in the steps of FIGS. Therefore, in order for the light from the optical fiber 7 to be appropriately collimated by the convex lens 4a, each time one optical fiber is inserted into the connection hole, the position of the optical fiber is changed while passing the light through the optical fiber. It is necessary to make adjustments and it is unavoidable that the operation is time-consuming and troublesome.
[0009]
Further, since the microlens array with the optical fiber connection holes is formed by processing the composite substrate in which the quartz glass layer 4 is formed on the silicon substrate 3, the surface on which the convex lenses 4a to 4c are formed in the quartz glass layer 4 It is not possible to form a convex lens on the opposite surface or to perform oblique polishing. In other words, for a biconvex lens type microlens array or a microlens array having an obliquely polished surface for suppressing reflected return light, both surfaces of the quartz glass layer 4 need to be used. A fiber connection hole cannot be formed, and coupling with an optical fiber array cannot be achieved.
[0010]
An object of the present invention is to provide a novel microlens array that can be easily and accurately coupled to an optical component such as an optical fiber array, and a method of manufacturing the same.
[0011]
[Means for Solving the Problems]
The microlens array according to the present invention comprises:
A light-transmitting substrate having a plurality of lenses and a plurality of metal fitting pins formed on one main surface;
An overlap portion that should overlap with the one main surface and a non-overlap portion that extends continuously to the overlap portion and does not overlap with the one main surface, and the overlap portion corresponds to the plurality of lenses. A light transmitting window and a plurality of fitting holes respectively corresponding to the plurality of fitting pins are provided, and the non-overlapping portion is formed of a metal coupling plate formed to provide a plurality of guide pin insertion holes. Wherein the plurality of fitting pins are fitted to the plurality of fitting holes in a state where the overlapping portion is overlapped with the one main surface, and the plurality of fitting pins are fitted to the board.
It is provided with.
[0012]
According to the microlens array of the present invention, a plurality of lenses and a plurality of metal fitting pins can be easily and accurately formed on one main surface of the translucent substrate by a thin film process. Further, the coupling plate having a plurality of fitting holes and a plurality of guide pin insertion holes can be formed easily and accurately by a thin film process. For this reason, the fitting accuracy of the fitting pin to the fitting hole is improved, and the fitting accuracy of the guide pin to the guide pin insertion hole is improved. Accordingly, the plurality of guide pins provided on an optical component such as an optical fiber are fitted into the plurality of guide pin insertion holes of the microlens array according to the present invention, whereby the coupling can be easily and accurately achieved.
[0013]
In the microlens array of the present invention, each fitting hole and / or each guide pin insertion hole may be formed so as to increase in size as approaching the substrate-side main surface of the coupling plate. Here, the size refers to a diameter or a length of one side. This facilitates insertion of the fitting pins into the respective fitting holes and facilitates insertion of the guide pins into the respective guide pin insertion holes. For this reason, each fitting hole and / or each guide pin insertion hole can be formed as small as possible, and precise fitting becomes possible.
[0014]
The manufacturing method of the microlens array according to the present invention includes:
A light-transmitting substrate in which a plurality of lenses are formed on one main surface and metal fitting pins are formed on the one main surface by plating; and an overlapping portion that should overlap the main surface on the one side. A non-overlapping portion that extends continuously to the overlapping portion and does not overlap with the one main surface, wherein the overlapping portion includes a light-transmitting window corresponding to the plurality of lenses and a plurality of fitting pins. Providing a plurality of fitting holes respectively corresponding to, and preparing a metal coupling plate formed by plating so as to provide a plurality of guide pin insertion holes in the non-overlapping portion,
Attaching the coupling plate to the board by fitting the plurality of fitting pins into the plurality of fitting holes in a state where the overlapping portion of the coupling plate is overlapped on one main surface of the board;
Is included.
[0015]
According to the method of manufacturing a microlens array of the present invention, a microlens array can be easily and accurately manufactured using a thin film process including plating.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a state before assembly of a microlens array according to an embodiment of the present invention, and a state after assembly of the microlens array is shown in FIG. FIG. 2 corresponds to a cross section taken along line XX ′ of FIG. The micro lens array LA includes a quartz substrate 10 and a metal coupling plate 20 mounted on the substrate.
[0017]
On one main surface of the quartz substrate 10, a convex lens L ₁ ~ L ₅ Are formed in a line, and the fitting pins 12 and 14 are ₁ ~ L ₅ Are formed on one side and the other side, respectively, of the lens row including. Lens L ₁ ~ L ₅ Is formed by transferring a lens pattern made of a resist onto one main surface of the substrate 10 by etching. Each of the fitting pins 12 and 14 is made of a metal such as a Ni—Fe alloy plated on one main surface of the substrate 10 via a plating base layer. The plating base layer corresponds to the Cu / Cr laminates 50 and 52 shown in FIG. 13, but is not shown in FIGS.
[0018]
The substrate 10 has a rectangular shape as an example. The length A of the long side is 6 mm, the length B of the short side is 1.5 mm, and the thickness T can be 1.25 mm. L ₁ Etc., the diameter of each lens can be 0.5 mm, and the pitch P (distance between lens centers) between adjacent lenses can be 0.5 mm.
[0019]
Coupling plate 20 has an overlapping portion that should overlap one main surface of substrate 10, and a non-overlapping portion that extends continuously from the overlapping portion and does not overlap with one main surface of substrate 10. Lens L ₁ ~ L ₅ , And fitting holes 24 and 26 corresponding to the fitting pins 12 and 14, respectively, and guide pin insertion holes 28 and 30 at the non-overlapping portions. It is made of a metal such as a Ni-Fe alloy. The light transmitting window 22 includes a lens L ₁ ~ L ₅ L allows the transmission of light passing through ₁ May be provided for each lens. Each of the fitting holes 24 and 26 is formed so as to penetrate from one main surface of the coupling plate 20 to the other main surface and increase in size (diameter) as approaching the other main surface. Each of the guide pin insertion holes 28 and 30 is formed so as to penetrate from one main surface of the coupling plate 20 to the other main surface and increase in size (diameter) as approaching the other main surface.
[0020]
The coupling plate 20 has a rectangular shape as an example. The length a of the long side can be 11 mm, the length b of the short side can be 3 mm, and the thickness t can be 50 to 100 μm. The translucent window 22 has a rectangular shape as an example. The length c of the long side can be 3 mm, and the length d of the short side can be 1 mm. The guide pin insertion holes 28 and 30 are used for inserting (fitting) the guide pins 32 and 34 provided in an optical component (for example, a fiber array) to be coupled with each other. The size of the opening at the small size end can be 1 mm, and the size of the opening at the large size end on the other main surface side of the coupling plate 20 can be 1.2 mm. Each of the guide pins 32 and 34 is a columnar member made of stainless steel or ceramic, and can have a diameter of 1 mm.
[0021]
The fitting holes 24 and 26 are formed so as to be located on a diagonal line of the light transmitting window 22, and the fitting pins 12 and 14 are formed at positions corresponding to the fitting holes 24 and 26. The positions and the number of the fitting pins may be changed, for example, the fitting pins are arranged at four corners of the light transmitting window 22. The same applies to the guide pin insertion holes 28 and 30.
[0022]
When assembling the microlens array LA, the fitting pins 12 and 14 are inserted into the fitting holes 24 and 26 in a state where the other main surface of the coupling plate 20 is overlapped on one main surface of the substrate 10 as shown in FIG. And the coupling plate 20 is coupled to the substrate 10. At this time, since the fitting pins are inserted into the respective fitting holes from the large size end side, the insertion can be performed easily and smoothly.
[0023]
Since the fitting pins 12 and 14 are formed on the lens forming surface of the substrate 10 by a thin film process with reference to the lens position as described later, the positional accuracy of the fitting pins 12 and 14 with respect to the lens position (error with respect to the design position). ) Can be within ± 0.2 μm. For this reason, the fitting accuracy of the fitting pins 12 and 14 to the fitting holes 24 and 26 can be within ± 0.3 μm, and the fitting accuracy of the guide pins 32 and 34 to the guide pin insertion holes 28 and 30. Can be within ± 0.5 μm.
[0024]
FIG. 2 shows a state where the microlens array LA is coupled to the optical fiber array FA as an example. As shown in FIGS. 2 and 3, the optical fiber array FA has holding holes H arranged in parallel from one end face of the optical fiber holder 36 to the other end face. ₁ ~ H ₅ And the optical fiber F ₁ ~ F ₅ The end face of each optical fiber is exposed to one end face of the optical fiber holder 36 so as to form a common plane with the one end face. The guide pin insertion hole P extends from one end face of the optical fiber holder 36 to the other end face. ₁ , P ₂ Is the holding hole H ₁ ~ H ₅ Are provided on one side and the other side of the holding hole group including the guide pin insertion hole P, respectively. ₁ , P ₂ , Guide pins 32 and 34 are slidably inserted respectively.
[0025]
When the microlens array LA is coupled to the optical fiber array FA, the coupling is performed in a state where the other main surface (the surface opposite to the lens forming surface) of the substrate 10 faces one end surface of the optical fiber array FA. The guide pins 32 and 34 are inserted (fitted) into the guide pin insertion holes 28 and 30 of the plate 20, respectively, and the other end surface of the substrate 10 approaches or contacts one end surface of the array FA. At this time, since the guide pins are inserted into the respective guide pin insertion holes from the large-size end side, the insertion can be performed easily and smoothly. Thereafter, the position of the microlens array LA in the optical axis direction is adjusted, and the microlens array LA can be bonded and fixed to the optical fiber array FA at the position where the desired collimated light is obtained. Since the adjustment work can be performed for each microlens array, work efficiency is improved. The microlens array LA of the present invention can achieve coupling with an optical fiber array with a positional accuracy within ± 1 μm.
[0026]
In the optical fiber array FA, the guide pins 32 and 34 are slidable, but may be fixed so as to protrude from one end face of the optical fiber holder 36. The optical component to be coupled is not limited to the optical fiber array, but may be a light emitting element array, a light receiving element array, or the like. The microlens substrate is not limited to the one-convex lens type, but may be a type shown in FIGS.
[0027]
The microlens substrate shown in FIG. 4 has a convex lens L on one main surface of a quartz substrate 10. ₁ ~ L ₅ And the metal fitting pins 12 and 14 are formed in the same manner as described above, and the lens L is provided on the other main surface of the substrate 10. ₁ ~ L ₅ Lenses L facing each other ₁₁ ~ L _Fifteen Is formed. Lens L ₁₁ ~ L _Fifteen Is the lens L ₁ ~ L ₅ Similarly, the lens pattern formed of the resist is transferred to the other main surface of the substrate 10 by etching.
[0028]
The microlens substrate shown in FIGS. 5 and 6 has a convex lens L on one main surface of a quartz substrate 10. ₁ ~ L ₅ And the metal fitting pins 12 and 14 are formed in the same manner as described above, and the lens L is provided on the other main surface of the substrate 10. ₁ ~ L ₅ The inclined surface forming portion 16 is provided to face the lens row including The inclined surface forming portion 16 forms an inclined surface having an inclination of θ = 5 to 15 degrees (preferably 8 degrees) with respect to the other main surface of the substrate 10 as shown in FIG. Direction is lens L ₁ ~ L ₅ Are set so as to face in a direction orthogonal to the arrangement direction.
[0029]
When using the micro lens array, the lens L ₁ As shown in FIG. ₁ From the lens L via the inclined surface forming portion 16 ₁ Light 18 is incident on the lens L. ₁ Is collimated (parallel light). At this time, the light 18r reflected on the inclined surface of the inclined surface forming section 16 is reflected by the optical fiber F as shown in FIG. ₁ Deviates from the optical fiber F ₁ Does not enter. That is, the provision of the inclined surface forming section 16 allows the optical fiber F ₁ Reflected light and F ₁ The reflected light incident on the optical fiber adjacent to the optical fiber can be reduced.
[0030]
Next, with reference to FIGS. 7 to 16, a method of manufacturing a microlens substrate of a one-convex lens type as shown in FIGS.
[0031]
In the step of FIG. 7, a resist layer 40 having a mark forming pattern 40m is formed by photolithography in alignment with one main surface of the quartz substrate 10. The thickness of the resist layer 40 can be about several μm.
[0032]
In the step of FIG. 8, a Cr film is formed to a thickness of about 300 nm by a sputtering method so as to cover the resist layer 40. At this time, a part of the Cr film adheres to one main surface of the substrate 10 via the alignment mark forming pattern 40m. Thereafter, when the resist layer 40 is removed together with the Cr film thereon by a lift-off process, the portion where the Cr film is adhered remains as the alignment mark M on one main surface of the substrate 10.
[0033]
In the step of FIG. 9, a resist layer R corresponding to five desired lenses is formed by photolithography using an alignment mark M. ₁ ~ R ₅ Is formed on one main surface of the substrate 10.
[0034]
In the step of FIG. ₁ ~ R ₅ Is subjected to a heat reflow treatment so that each resist layer forms a spherical convex portion.
[0035]
In the step of FIG. ₁ ~ R ₅ Then, a dry etching process is performed on one main surface of the quartz substrate 10 to form a resist layer R on one main surface of the quartz substrate 10. ₁ ~ R ₅ Is transferred to the resist layer R ₁ ~ R ₅ L corresponding to each ₁ ~ L ₅ To form
[0036]
In the step of FIG. 12, a resist layer 42 having holes 44 and 46 corresponding to two desired fitting pins is formed on one main surface of the substrate 10 by photolithography using an alignment mark M. At this time, the lens L ₁ ~ L ₅ The alignment mark M is covered with the resist layer 42.
[0037]
In the step of FIG. 13, a Cu / Cr laminate (a laminate of a Cr layer and a Cu layer) 48 is formed by a sputtering method so as to cover the resist layer 42. At this time, Cu / Cr laminates 50 and 52 adhere to the substrate surfaces in the holes 44 and 46 of the resist layer 42. The thicknesses of the Cr layer and the Cu layer can be 30 nm and 300 nm, respectively. The Cr layer is for improving the adhesion of the Cu layer to the substrate 10.
[0038]
In the step of FIG. 14, the resist layer 42 is removed together with the Cu / Cr laminate 48 thereon by lift-off processing, and the Cu / Cr laminates 50 and 52 are left as plating base layers on one main surface of the substrate 10. Then, a resist layer 54 having holes 56 and 58 exposing the Cu / Cr laminates 50 and 52, respectively, is formed on one main surface of the substrate 10 by photolithography using the alignment mark M. The thickness of the resist layer 54 can be about 50 to 100 μm.
[0039]
In the step of FIG. 15, the fitting pins 12 and 14 made of the Ni—Fe alloy are selectively plated with the Cu / Cr alloy inside the holes 56 and 58 of the resist layer 54 by selective plating of the Ni—Fe alloy using the resist layer 54 as a mask. It is formed on the laminates 50 and 52.
[0040]
In the step of FIG. 16, the resist layer 54 is removed by a chemical treatment or the like. As a result, a convex lens L is formed on one main surface of the quartz substrate 10 as a microlens substrate. ₁ ~ L ₅ Is formed, and the lens L ₁ ~ L ₅ Are obtained in which the fitting pins 12 and 14 are formed on one side and the other side of the lens row including the Cu / Cr laminates 50 and 52, respectively.
[0041]
According to the manufacturing method described above with reference to FIGS. ₁ ~ L ₅ In both the photolithography process for forming the mask and the photolithography process for forming the fitting pins 12 and 14, since the exposure process was performed using the reduction projection exposure apparatus based on the alignment mark M, the design position Good positional accuracy with an error of ± 0.2 μm or less was obtained.
[0042]
In the above-described method for manufacturing a microlens substrate, the lens L is used as the microlens substrate. ₁ ~ L ₅ Has shown an example in which a one-dimensional array is formed, but a lens in which a plurality of lenses form a two-dimensional array can be similarly created.
[0043]
Next, an example of a method of manufacturing a coupling plate will be described with reference to 17 to 22.
[0044]
In the process of FIG. 17, a Cu / Cr laminate 62 is formed as a plating underlayer on one main surface of a substrate 60 made of, for example, glass, quartz, silicon, or the like by a sputtering method. The thicknesses of the Cr layer and the Cu layer can be 30 nm and 300 nm, respectively.
[0045]
In the step of FIG. 18, a resist layer R corresponding to a desired light-transmitting window pattern is formed by photolithography. ₁₁ And a resist layer R corresponding to a desired fitting hole pattern. ₁₂ , R _Thirteen And resist layers R respectively corresponding to desired guide pin insertion hole patterns. ₁₄ , R _Fifteen Are formed on the Cu / Cr laminate 62. Resist layer R ₁₁ Is formed to have a size slightly larger than the light transmitting window, and the resist layer R ₁₂ , R _Thirteen Are formed to have a size (diameter) slightly larger than the fitting hole, and the resist layer R ₁₄ , R _Fifteen Are formed to have a slightly larger size (diameter) than the guide pin insertion hole. Resist layer R ₁₁ ~ R _Fifteen All allow the size of the opening to gradually increase outward.
[0046]
Next, in the step of FIG. 19, a resist layer 64, R ₂₂ ~ R ₃₀ To form The resist layer 64 is formed so as to have holes 64a corresponding to a desired planar pattern of the bonding plate. Resist layer R ₂₂ , R ₂₄ , R ₂₆ , R ₂₈ , R ₃₀ Indicates that each of the resist layers R ₁₁ , R ₁₂ , R _Thirteen , R ₁₄ , R _Fifteen On top of. Resist layer R ₂₂ Is equivalent to a light transmitting window, and is formed to have a size corresponding to the light transmitting window. Resist layer R ₂₄ , R ₂₆ Each of them corresponds to a fitting hole and is formed to have a size (diameter) corresponding to the fitting hole. Resist layer R ₂₈ , R ₃₀ Each corresponds to a guide pin insertion hole, and is formed to have a size (diameter) corresponding to the guide pin insertion hole.
[0047]
In the process of FIG. 20, the resist layer 64, R ₁₁ ~ R _Fifteen , R ₂₂ ~ R ₃₀ The coupling plate 20 made of a Ni—Fe alloy layer is formed by selective plating of a Ni—Fe alloy using as a mask. At this time, the bonding plate 20 is ₂₂ ~ R ₃₀ Are formed such that as they move upward around the respective resist layers, they become more distant from the respective resist layers (so that the size of the openings increases as they move upward). This is R ₂₂ And the like, the Cu / Cr laminate 62 as a plating underlayer ₁₁ This is due to the fact that the growth of plating is delayed as compared with the portion located just above the Cu / Cr laminate 62 because the resist layer is covered with the resist layer.
[0048]
In the step of FIG. 21, the resist layer 64, R ₁₁ ~ R _Fifteen , R ₂₂ ~ R ₃₀ Is removed to provide the light transmitting window 22, the fitting holes 24 and 26, and the guide pin insertion holes 28 and 30 to the coupling plate 20.
[0049]
In the step of FIG. 22, the coupling layer 20 is separated from the substrate 60 by removing the Cu layer in the Cu / Cr laminate 62 by etching. The Cr layer 62a is left on the substrate 60. The substrate 60 can be used repeatedly by forming a Cu layer on the Cr layer 62a by a sputtering method.
[0050]
FIGS. 23 to 26 show another example of the method of manufacturing the coupling plate according to the present invention. The same parts as those in FIGS. 17 to 22 are denoted by the same reference numerals, and detailed description is omitted.
[0051]
In the process of FIG. 23, holes Q corresponding to a desired light-transmitting window pattern are formed. ₁ And a hole Q corresponding to a desired fitting hole pattern. ₂ , Q ₃ And a hole Q corresponding to a desired guide pin insertion hole pattern. ₄ , Q ₅ Is formed on one main surface of the substrate 60 as a plating base layer. Hole Q ₁ Are formed in a size slightly larger than the light transmitting window. Hole Q ₂ , Q ₃ Are formed in a size (diameter) slightly larger than the fitting hole, and the hole Q ₄ , Q ₅ Are formed in a size (diameter) slightly larger than the guide pin insertion hole. Hole Q ₁ ~ Q ₅ All allow the size of the opening to gradually increase outward.
[0052]
Hole Q ₁ ~ Q ₅ In order to obtain a Cu / Cr laminate 62 having ₁ ~ Q ₅ After forming a resist layer for lift-off corresponding to each of the above, a Cu / Cr layer 62 is formed on one main surface of the substrate 60 by covering the respective resist layers by a sputtering method, and the respective resist layers are formed thereon by a lift-off process. Removed with Cu / Cr stack. When forming the Cu / Cr laminate 62 by a sputtering method, the thicknesses of the Cr layer and the Cu layer can be 15 nm and 200 nm, respectively.
[0053]
Next, in the same manner as described above with reference to FIG. ₂₂ ~ R ₃₀ To form The resist layer 64 is formed so as to have holes 64a corresponding to a desired planar pattern of the bonding plate. Resist layer R ₂₂ , R ₂₄ , R ₂₆ , R ₂₈ , R ₃₀ Is a hole Q in the hole 64a. ₁ , Q ₂ , Q ₃ , Q ₄ , Q ₅ It is formed so as to be located inside. As a result, the resist layer R ₂₂ ~ R ₃₀ In the peripheral portion of each of the resist layers, the surface portion of the substrate 60 is exposed in a ring shape.
[0054]
In the step shown in FIG. ₂₂ ~ R ₃₀ The coupling plate 20 made of a Ni—Fe alloy layer is formed by selective plating of a Ni—Fe alloy using as a mask. At this time, R ₂₂ In the peripheral portion of each resist layer such as above, the Cu / Cr laminate 62 as a plating base film is lacking in an annular shape, so that the growth of plating is delayed as compared with the portion located directly above the Cu / Cr laminate 62. . For this reason, the coupling plate 20 ₂₂ And the like, so that the opening increases with increasing distance around the periphery of each resist layer (so that the size of the opening increases with increasing distance).
[0055]
In the process of FIG. 25, the resist layer 64, R ₂₂ ~ R ₃₀ Is removed to provide the light transmitting window 22, the fitting holes 24 and 26, and the guide pin insertion holes 28 and 30 to the coupling plate 20.
[0056]
In the step of FIG. 26, the coupling layer 20 is separated from the substrate 60 by removing the Cu layer in the Cu / Cr stack 62 by etching. The Cr layer 62a is left on the substrate 60.
[0057]
FIG. 27 shows still another example of the coupling plate according to the present invention. The same parts as those in FIGS. 17 to 26 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0058]
In the step of FIG. 27A, the resist layers 64 and R are formed on the Cu / Cr laminate 62 covering one main surface of the substrate 60. ₂₂ , R ₂₄ , R ₂₈ To form The resist layer 64 is formed so as to have holes 64a corresponding to a desired planar pattern of the bonding plate. Resist layer R ₂₂ , R ₂₄ , R ₂₈ Are formed such that their size increases from the upper part to the lower part in the hole 64a. Where layer R ₂₂ , R ₂₄ , R ₂₈ In order to obtain a forward tapered resist shape as described above, when a stepper (reduction projection exposure apparatus) is used,
(1) a method of setting the focus position in the resist,
(2) a method of setting a small exposure amount below the resist (a method for a positive resist);
(3) A method of gradually changing the transmittance of the mask portion of the exposure mask (to increase the transmittance toward the bottom of the resist)
Any of the methods can be used.
[0059]
In the step of FIG. 27B, the resist layers 64, R ₂₂ , R ₂₄ , R ₂₈ The coupling plate 20 made of a Ni—Fe alloy layer is formed by selective plating of a Ni—Fe alloy using as a mask. Then, the resist layer 64, R ₂₂ , R ₂₄ , R ₂₈ Is removed. Resist layer R ₁ ~ R ₄ , R ₂₁ ~ R ₂₄ Is removed, the coupling plate 20 is provided with the light transmitting window 22, the fitting hole 24, and the guide pin layer through hole. Since the size of the light transmitting window 22, the fitting hole 24, and the guide pin layer through hole 28 all increase as the corresponding resist layer proceeds from the upper part to the lower part, the light transmitting window 22, the fitting hole 24, and the guide pin layer through hole 28 move from the upper surface to the lower surface of the coupling plate 20. As the size increases. Thereafter, the Cu layer in the Cu / Cr stack 62 is removed by etching, and the coupling plate 20 is separated from the substrate 60. FIGS. 27A and 27B show a method of manufacturing about half of the microlens substrate, but the other half can be manufactured in the same manner.
[0060]
According to the method of manufacturing the coupling plate described above with reference to FIGS. 17 to 27, the positions and sizes of the light transmitting window 22, the fitting holes 24 and 26, and the guide pin insertion holes 28 and 30 are set with submicron accuracy such as 0.5 μm. can do.
[0061]
According to the method of manufacturing the coupling plate described above with reference to FIGS. 23 to 26, the following additional effects (a) and (b) can be obtained.
[0062]
(A) In the step of FIG. ₁₁ ~ R _Fifteen Is 2 μm or more, so that unevenness on the substrate is large. For this reason, in the step of FIG. 19, the flatness of the resist application is easily deteriorated, and ₂₂ ~ R ₃₀ Tends to cause dimensional fluctuations. On the other hand, in the step of FIG. 23, since the resist layer for lift-off is removed and the thickness of the Cu / Cr laminate 62 is as thin as about 200 nm, the unevenness on the substrate is small. For this reason, in the step of FIG. 23, the uniformity of resist application is improved, and the resist layer 64, R ₂₂ ~ R ₃₀ Is reduced. Therefore, the production yield of the coupling plate 20 is improved.
[0063]
(B) In the step of FIG. ₂₂ , R ₂₄ , R ₂₆ , R ₂₈ , R ₃₀ Under the resist layer R ₁₁ , R ₁₂ , R _Thirteen , R ₁₄ , R _Fifteen The plating process is performed in the presence of each of them, so that even if the resist is removed in the step of FIG. 21 and the Cu etching is performed in the step of FIG. 22, the fitting holes 24 and 26 and the guide pin insertion holes 28 , 30 remain in the resist, which easily causes contamination. The contamination lowers the positioning accuracy when inserting the guide pins and the fitting pins into the coupling plate 20 as shown in FIG. On the other hand, in the step of FIG. ₂₂ ~ R ₃₀ Since the plating process is performed in a state where no resist layer is present under the resist, the amount of the resist adhered to and remaining on the coupling plate 20 is reduced, and contamination can be reduced. Therefore, the positioning accuracy when the guide pins and the fitting pins are inserted through the coupling plate is improved.
[0064]
【The invention's effect】
As described above, according to the present invention, a plurality of metal fitting pins are formed on a lens forming surface of a substrate, and a light transmitting window corresponding to a plurality of lenses of the substrate is formed on a metal coupling plate. A plurality of fitting holes and a plurality of guide pin insertion holes respectively corresponding to the plurality of fitting pins are provided, and the coupling plate is mounted on the substrate by fitting the plurality of fitting pins and the plurality of fitting holes. Since the lens array is configured, it is possible to easily and accurately achieve the coupling simply by inserting the plurality of guide pins provided on the optical component such as the optical fiber array into the plurality of guide pin insertion holes of the micro lens array. Can be Further, the microlens array of the present invention has an advantage that it can be easily and accurately manufactured by a thin film process including plating.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a state before assembling a microlens array according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a state where the microlens array of FIG. 1 is assembled and then coupled to an optical fiber array.
FIG. 3 is an end view of the optical fiber array of FIG. 2;
FIG. 4 is a cross-sectional view showing another example of the microlens substrate.
FIG. 5 is a sectional view showing still another example of the microlens substrate.
FIG. 6 is a cross-sectional view of the microlens substrate of FIG. 5 taken along line YY ′.
FIG. 7 is a cross-sectional view showing a resist layer forming step in the method for manufacturing a microlens substrate according to the present invention.
FIG. 8 is a cross-sectional view showing a sputtering step and a lift-off step subsequent to the step of FIG. 7;
FIG. 9 is a cross-sectional view showing a resist layer forming step following the step in FIG. 8;
FIG. 10 is a sectional view showing a registry flow step following the step of FIG. 9;
FIG. 11 is a cross-sectional view showing a lens forming step following the step of FIG. 10;
FIG. 12 is a cross-sectional view showing a resist layer forming step following the step of FIG. 11;
FIG. 13 is a sectional view showing a sputtering step following the step of FIG. 12;
FIG. 14 is a cross-sectional view showing a lift-off step and a resist layer forming step following the step of FIG.
FIG. 15 is a cross-sectional view showing a selective plating step following the step of FIG. 14;
FIG. 16 is a cross-sectional view showing a resist removing step following the step in FIG. 15;
FIG. 17 is a cross-sectional view showing a plating underlayer forming step in an example of the method of manufacturing a coupling plate according to the present invention.
FIG. 18 is a cross-sectional view showing a resist layer forming step following the step of FIG. 17;
FIG. 19 is a cross-sectional view showing a resist layer forming step following the step in FIG. 18;
FIG. 20 is a cross-sectional view showing a selective plating step following the step of FIG. 19;
FIG. 21 is a cross-sectional view showing a resist removing step following the step of FIG. 20;
FIG. 22 is a cross-sectional view showing a separation step following the step of FIG. 21.
FIG. 23 is a cross-sectional view showing a plating base layer forming step and a resist layer forming step in another example of the method of manufacturing a coupling plate according to the present invention.
FIG. 24 is a sectional view showing a selective plating step following the step of FIG. 23;
FIG. 25 is a cross-sectional view showing a resist removing step following the step in FIG. 24;
FIG. 26 is a cross-sectional view showing a separation step following the step of FIG. 25.
FIGS. 27A and 27B are cross-sectional views showing still another example of the method of manufacturing a coupling plate according to the present invention, wherein FIG. 27A shows a resist layer forming step, and FIG. It is.
FIG. 28 is a cross-sectional view showing a resist layer forming step in a conventional microlens array manufacturing method.
FIG. 29 is a cross-sectional view showing a lens forming step and a resist layer forming step subsequent to the step of FIG. 28;
FIG. 30 is a cross-sectional view showing a selective etching step following the step of FIG. 29;
FIG. 31 is a cross-sectional view showing a state where optical fibers are mounted on the optical fiber array of FIG. 30;
[Explanation of symbols]
10, 60: quartz substrate, 12, 14: fitting pin, 20: coupling plate, 22: translucent window, 24, 26: fitting hole, 28, 30, P ₁ , P ₂ : Guide pin insertion hole, 32, 34: guide pin, 36: optical fiber holder, 40, 42, 54, 64, R ₁ ~ R ₅ , R ₁₁ ~ R _Fifteen , R ₂₂ ~ R ₃₀ : Resist layer, 48 to 52, 62: Cu / Cr laminated, L ₁ ~ L ₅ : Lens, LA: micro lens array, H ₁ ~ H ₅ : Holding hole, F ₁ ~ F ₅ : Optical fiber, FA: optical fiber array, M: alignment mark.

Claims (4)

A light-transmitting substrate having a plurality of lenses and a plurality of metal fitting pins formed on one main surface;
An overlap portion that should overlap with the one main surface and a non-overlap portion that extends continuously to the overlap portion and does not overlap with the one main surface, and the overlap portion corresponds to the plurality of lenses. A light transmitting window and a plurality of fitting holes respectively corresponding to the plurality of fitting pins are provided, and the non-overlapping portion is formed of a metal coupling plate formed to provide a plurality of guide pin insertion holes. A plurality of fitting pins respectively fitted in the plurality of fitting holes in a state where the overlapping portion is overlapped with the one main surface, and the plurality of fitting pins are mounted on the substrate. . 2. The microlens array according to claim 1, wherein each of the plurality of fitting holes increases in size as approaching the main surface of the coupling plate on the substrate side. 3. 3. The microlens array according to claim 1, wherein each of the plurality of guide pin insertion holes is formed so as to increase in size as approaching the main surface of the coupling plate on the substrate side. 4. A light-transmitting substrate in which a plurality of lenses are formed on one main surface and metal fitting pins are formed on the one main surface by plating; and an overlapping portion that should overlap the main surface on the one side. A non-overlapping portion that extends continuously to the overlapping portion and does not overlap with the one main surface, wherein the overlapping portion includes a light-transmitting window corresponding to the plurality of lenses and a plurality of fitting pins. Providing a plurality of fitting holes respectively corresponding to, and preparing a metal coupling plate formed by plating so as to provide a plurality of guide pin insertion holes in the non-overlapping portion,
Attaching the coupling plate to the board by fitting the plurality of fitting pins into the plurality of fitting holes in a state where the overlapping portion of the coupling plate is overlapped on one main surface of the board. Manufacturing method of micro lens array including.

Images