JPH11258429A - Method for mounting optical bloc, optical system with optical bloc mounted, method for forming optical block and optical block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and highly precisely mount an optical block by passive alignment. SOLUTION: This method for mounting an optical block is carried out by utilizing a photolithographic technology to simultaneously form CGH (computerized hologram) elements 12 and dicing marks 14 on a transparent substrate 10. Then, a plurality of transparent substrates 10 on which the CGH elements 12 and the dicing marks 14 are formed are layered one another to give a layered substrate unit. After that, the layered substrate unit is died along the dicing marks to cut out optical blocks in which a plurality of transparent substrate blocks comprising CGH elements, respectively are layered. Finally, one of cut cross-section faces of each optical block formed by the dicing is brought into contact with the standard face to mount each optical block on a flat substrate for mounting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for mounting an optical block as an optical device constituting a free-space optical wiring optical system, an optical system mounting the optical block, a method for forming an optical block, and an optical block. Computer generated hologram (hereinafter “CG”)
H element ". ) And an implementation thereof.

[0002]

2. Description of the Related Art In recent years, a diffraction optical system utilizing a diffraction phenomenon,
Among them, a computer generated hologram (CGH element) formed using a computer has attracted attention because it has the following advantages. The CGH element has an advantage that it can be formed on a transparent substrate by using a conventional LSI fabrication technique, in particular, a photolithography technique. In addition, the CGH element has an advantage that the function of, for example, a complicated aspheric lens can be realized by one substrate. In addition, the CGH element has an advantage that optical characteristics such as a focal length and a deflection angle can be arbitrarily controlled and formed.

An optical block cut out from the transparent substrate on which the CGH element is formed so as to include the CGH element constitutes a free-space optical wiring optical system.

The optical block may be cut out from only one transparent substrate. For example, if a plurality of transparent substrates on which CGH elements are formed are laminated and the optical block is cut out from this, for example, light A plurality of functions such as demultiplexing, multiplexing, collimating, and condensing can be realized by one optical block as one hologram. Then, this optical block functions as an optical device constituting a free-space optical wiring optical system.

[0005] The inventor of the present application has proposed such a CG.
A free-space optical interconnection optical system constituted by H elements is proposed in Japanese Patent Application No. 9-147115. This free space optical interconnection optical system constitutes an optical device for an optical communication terminal station.

[0006]

In assembling and mounting an optical system using this optical block and other optical elements, for example, an optical fiber, a light source, a light receiving element, and the like, the optical block and each optical element must be connected to each other. It is necessary to perform alignment with high accuracy.

The optical block and each optical element have three-dimensional degrees of freedom. For this reason,
In order to perform positioning, a light source serving as a reference for positioning is usually used, or an optical signal serving as a reference for positioning is externally introduced, and then the positioning of the optical block and each optical element is performed using a fine adjustment table. Was required to be performed with high accuracy. Then, in such a so-called active alignment, there is a problem that it takes time and effort for alignment. As a result, there is a problem that the manufacturing cost of the optical system increases.

Therefore, there has been a demand for a technique capable of easily and accurately mounting an optical block without introducing a reference optical signal or the like from the outside, that is, by so-called passive alignment.

[0009]

As a result of various studies and experiments, the inventor of the present application has focused on using a planar mounting substrate in assembling an optical system using an optical block. For the board for planar mounting, see, for example, Reference 1: "1997 IEICE Electronics Society Conference, Paper No. C-3-8.
8 "as a micro-optical bench (MOB). By using this MOB, optical components such as an optical fiber and a flat microlens can be arranged by passive alignment.

Further, the present inventor, when mounting the optical block by bringing the side surface of the optical block into contact with the reference surface of the planar mounting substrate, uses the side surface of the optical block as a reference for the optical axis of a computer generated hologram included in the optical block. It was conceived that the optical block could be easily mounted with high positional accuracy as designed by passive alignment if it was formed with high positional accuracy. Then, it was conceived that if the dicing marks of the optical block were formed with high positional accuracy, the side surfaces as cut surfaces of the optical block cut out by dicing could be formed with high positional accuracy. Then, they have conceived that if the dicing marks are formed using photolithography, the dicing marks can be formed with high positional accuracy.

(First mounting method of optical block) Therefore, according to the first mounting method of the optical block of the present invention, the mounting method of the optical block for mounting the optical block on a planar mounting substrate having a reference surface is provided. (A) a step of forming a computer generated hologram (CGH element) on a transparent substrate using a photolithography technique, and (b) a step of forming a CGH on a transparent substrate using a photolithography technique.
Forming a dicing mark in a specific positional relationship with the element; and (c) dicing the processed transparent substrate on which the CGH element and the dicing mark are formed along the dicing mark, thereby forming an optical block including the CGH element. And (d) contacting at least one of the cut surfaces of the optical block by dicing with a reference surface to install the optical block on a planar mounting substrate. .

As described above, according to the first mounting method of the optical block of the present invention, the dicing mark is formed by using the photolithography technique. For this reason, the position of the dicing mark from the optical axis of the CGH element can be accurately determined. Since the dicing is performed along the dicing mark, the position of the cut surface formed by the dicing has high accuracy. That is, the cut surface as the side surface of the optical block can be formed with high positional accuracy. In the present invention, the photolithography technique includes not only a resist pattern forming process but also an etching process.

Then, the cut surface is brought into contact with the reference surface of the planar mounting substrate to mount the optical block.
This reference plane can be mounted without any degree of freedom in the vertical direction. In addition, because the accuracy of the position of the cut surface is good,
The distance between the reference plane and the optical axis of the CGH element included in the optical block can be accurately determined. As a result, the optical block can be accurately mounted by passive alignment.

The optical block is preferably a hexahedron. If it is a hexahedron, it may be a rectangular parallelepiped or a cube. More preferably, the optical block is a hexahedron having a structure in which the optical axis is in a plane parallel to at least one plane.

Further, if another optical element is mounted on the board for planar mounting, the alignment between the optical block and another optical element constituting the same optical system can be easily performed. For example, if an optical fiber is mounted by providing a V-shaped groove on a planar mounting substrate, the optical fiber can be installed with high positional accuracy. As a result, the alignment between the optical fiber and the optical block can be easily performed.

In carrying out the method of mounting an optical block according to the present invention, it is preferable to perform the step (b) during the step (a).

As described above, if the dicing mark is formed substantially simultaneously with the CGH element by performing the step (b) during the step (a), the dicing mark and the CGH element can be formed by one photolithography process. Can be formed. As a result, the manufacturing process can be simplified as compared with the case where the dicing mark and the CGH element are separately formed.

In practicing the present invention, it is preferable that the dicing mark is formed at each vertex of a square surrounding the CGH element and at a position equidistant from the optical axis of the CGH element.

As described above, if the optical axis of the CGH element is coincident with the center of the square (the intersection of the straight line connecting the opposing vertices) when the block cut out by dicing is viewed from the upper surface, the dicing is performed. The distance between each of the four side surfaces of the optical block and the optical axis of the CGH element becomes equal to each other. Therefore, any of the four side surfaces can be used as a surface that comes into contact with the reference surface during mounting.

The above-mentioned dicing mark can be formed as a groove or a projection formed by etching a transparent substrate. However, when the dicing mark is formed on the surface of the transparent substrate by the etching of the photolithography technique, the transmittance of the portion of the dicing mark and the transmittance of the surrounding portion remain the same. Therefore, in order to visually observe the dicing mark with a microscope at the time of positioning, it is necessary to completely focus on the surface of the transparent substrate. For this purpose, for example, a method of focusing on a dicing mark by focusing on a CGH element formed on the surface of a transparent substrate can be considered. However, in this method, CGH
If there is no dicing mark in the same field of view as the device,
After focusing on the GH element, it is necessary to move the microscope stage to find a dicing mark. In that case,
It takes time to check the dicing mark. In this case, it is not preferable to recognize the position of the dicing mark using an image processing technique.

Therefore, in practicing the present invention, the dicing mark is preferably formed as a metal mark provided on a transparent substrate.

Since the metal mark does not transmit light, it can be easily identified from the surrounding area. Therefore, if a metal mark is used as the dicing mark, the position of the dicing mark can be confirmed even if the surface of the transparent substrate on which the dicing mark is formed is not completely in focus.
Therefore, the work of confirming the position of the dicing mark can be performed quickly. The use of metal marks is also suitable for automatically recognizing dicing marks in image processing.

In practicing the present invention, preferably, the substrate for planar mounting is a silicon terrace (MOB).

In the method of mounting an optical block according to the present invention, preferably, the step (c) includes: (c1) a step of laminating a plurality of processed transparent substrates together to form a laminated substrate group; c2) dicing the stacked substrate group along the dicing mark to cut out an optical block.

As described above, by dicing the laminated substrate group in which the transparent substrates each having the CGH element formed thereon are laminated, an optical block in which a plurality of transparent substrate blocks each having the CGH element formed thereon can be formed. it can.

In the optical block mounting method according to the present invention, preferably, the dicing marks also serve as reference marks for positioning each other when a plurality of transparent substrates are laminated.

As described above, if the dicing mark and the arrangement mark are shared, the number of patterns formed by photolithography can be reduced.

(Method of Mounting the Second Optical Block)
According to the second mounting method of an optical block of the present invention, there is provided a mounting method of an optical block for mounting an optical block on a planar mounting substrate having a reference surface, wherein (a) photolithography is performed on a transparent substrate. A step of forming a computer generated hologram (CGH element) using the technology, and (b) a step of forming a dicing mark on the transparent substrate in a specific positional relationship with the CGH element using a photolithography technique,
(C) a step of laminating the processed transparent substrates on which the CGH elements and the dicing marks are formed to form a laminated substrate group; and (d) dicing the laminated substrate group along the dicing marks. (E) contacting at least one of the cut surfaces of the optical block by dicing with a reference surface to cut out an optical block composed of stacked transparent substrate blocks including a CGH element, thereby mounting the optical block on a plane. And placing it on a substrate.

As described above, according to the mounting method of the second optical block of the present invention, the dicing mark is formed using the photolithography technique. For this reason, the position of the dicing mark from the optical axis of the CGH element can be accurately determined. Then, since a laminated substrate group in which a plurality of processed transparent substrates are laminated is diced along the dicing mark, the position of the cut surface formed by the dicing has high accuracy. That is,
The cut surface as the side surface of the optical block can be formed with high positional accuracy. In the present invention, the photolithography technique includes not only a resist pattern forming process but also an etching process.

Then, the cut surface is brought into contact with the reference surface of the planar mounting substrate, and the optical block is mounted.
This reference plane can be mounted without any degree of freedom in the vertical direction. In addition, because the accuracy of the position of the cut surface is good,
The distance between the reference plane and the optical axis of the CGH element included in the optical block can be accurately determined. As a result, the optical block can be accurately mounted by passive alignment.

The optical block is preferably a hexahedron. If it is a hexahedron, it may be a rectangular parallelepiped or a cube. More preferably, the optical block is a hexahedron having a structure in which the optical axis is in a plane parallel to at least one plane.

Further, if another optical element is mounted on the flat mounting board, the alignment between the optical block and another optical element constituting the same optical system can be easily performed. For example, if an optical fiber is mounted by providing a V-shaped groove on a planar mounting substrate, the optical fiber can be installed with high positional accuracy. As a result, the alignment between the optical fiber and the optical block can be easily performed.

[0033] In the second method for mounting a block according to the present invention, preferably, during the step (a),
Step (b) is preferably performed.

In practicing the present invention, the dicing mark is preferably formed at each vertex of a square surrounding the computer hologram and at the same distance from the optical axis of the computer hologram.

In practicing the present invention, it is preferable to form a metal mark as the dicing mark.

In practicing the present invention, it is preferable to use a silicon terrace as the planar mounting substrate.

In practicing the present invention, it is preferable that the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of transparent substrates are laminated.

(Optical System Mounted with Optical Block)
According to the optical system in which the optical block of the present invention is mounted, an optical system in which the optical block is mounted on a planar mounting substrate having a reference surface, wherein the optical block has a computer-generated hologram and a dicing mark formed thereon. From the transparent substrate,
It is cut out as an area including the computer generated hologram by dicing along the dicing mark, and the dicing mark is formed using a photolithography technique.

As described above, according to the optical system in which the optical block of the present invention is mounted, the dicing mark for forming the optical block is formed using the photolithography technique. For this reason, the position of the dicing mark can be accurately determined with respect to the distance from the optical axis of the optical block. Since the dicing is performed along the dicing mark formed with high positional accuracy, the position of the cut surface formed by the dicing has high accuracy. That is, the side surface as the cut surface of the optical block has high positional accuracy.

Since the cut surface is a flat surface and the optical block is mounted by bringing the cut surface into contact with the reference surface of the planar mounting substrate, the degree of freedom in the vertical direction is eliminated from the reference surface. And can be implemented. In addition, since the accuracy of the position of the cut surface is high, the distance between the reference surface and the optical axis of the optical block is determined with high accuracy. As a result, according to this optical system, the optical block can be mounted with high precision by passive alignment.

Further, if another optical element is mounted on the planar mounting substrate, the alignment between the optical block and the other optical element can be easily performed. For example, if an optical fiber is mounted by providing a V-shaped groove, the positioning of the optical fiber and the optical block can be easily performed.

In implementing the optical system having the optical block according to the present invention, preferably, the dicing mark is located at each vertex of a square surrounding the CGH element,
It is desirable that the CGH element is formed at a position equidistant from the optical axis of the CGH element.

In practicing the present invention, preferably, the dicing mark is a metal mark.

In practicing the present invention, it is preferable that the planar mounting substrate is a silicon terrace.

In the optical system mounted with the optical block of the present invention, preferably, the optical block is cut out by dicing a laminated substrate group in which processed transparent substrates are laminated together along a dicing mark. Good thing.

As described above, by dicing the laminated substrate group in which the transparent substrates on which the CGH elements are formed are diced, an optical block in which a plurality of transparent substrate blocks on which the CGH elements are formed is formed. it can.

In the optical system having the optical block according to the present invention, preferably, the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of transparent substrates are laminated.

(Method of Forming First Optical Block)
According to the method of forming an optical block of the present invention, (a) a step of forming a computer generated hologram (CGH element) on a transparent substrate by using photolithography technology; and (b) a photolithography technology on the transparent substrate. Use this C
Forming a dicing mark in a specific positional relationship with the GH element; and (c) dicing the processed transparent substrate on which the computer generated hologram and the dicing mark are formed along the dicing mark, thereby forming an optical element including the CGH element. Cutting out blocks.

As described above, according to the optical block forming method of the present invention, the dicing mark is formed by using the photolithography technique. Therefore, the distance from the optical axis of the optical block to the position of the dicing mark can be accurately determined. Since the dicing is performed along the dicing mark, the position of the cut surface formed by the dicing has high accuracy in the distance from the optical axis. That is, the cut surface as the side surface of the optical block can be formed with high positional accuracy.

Therefore, if the cut surface is brought into contact with the mounting object and the optical block is mounted, the optical block can be mounted with high precision by passive alignment.

In carrying out the method of forming an optical block according to the present invention, it is preferable to perform the step (b) during the step (a). In the method of forming an optical block according to the present invention, The dicing mark for each C
It is desirable to form each of the vertices of a square surrounding the GH element at the same distance from the optical axis of the CGH element.

In practicing the present invention, it is preferable to form a metal mark as the dicing mark.

In the method of forming an optical block according to the present invention, preferably, the step (c) comprises: (c1) a step of laminating a plurality of processed transparent substrates together to form a laminated substrate group; c2) By dicing the laminated substrate group along the dicing mark, each CGH
Cutting out an optical block having a configuration in which transparent substrate blocks including elements are stacked.

As described above, by dicing the laminated substrate group in which the transparent substrates each having the CGH element formed thereon are laminated, an optical block in which a plurality of transparent substrate blocks each having the CGH element formed thereon can be formed. it can.

In the method of forming an optical block according to the present invention, it is preferable that the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of transparent substrates are laminated.

(Method of Forming Second Optical Block)
According to the second optical block forming method of the present invention,
(A) a step of forming a computer generated hologram (CGH element) on a transparent substrate by using photolithography technology; and (b) a step of forming a specific positional relationship with the CGH element on the transparent substrate by using photolithography technology. A step of forming a dicing mark; (c) a step of laminating a processed transparent substrate on which the CGH element and the dicing mark are formed to form a laminated substrate group; and (d) a step of forming the laminated substrate group along the dicing mark. And cutting out an optical block composed of laminated transparent substrate blocks each including a CGH element by dicing.

As described above, according to the optical block forming method of the present invention, the dicing marks are formed by using the photolithography technique. Therefore, the distance from the optical axis of the optical block to the position of the dicing mark can be accurately determined. Since the dicing is performed along the dicing mark, the position of the cut surface formed by the dicing has high accuracy in the distance from the optical axis. That is, the cut surface as the side surface of the optical block can be formed with high positional accuracy.

Therefore, if the cut surface is brought into contact with the mounting object and the optical block is mounted, the optical block can be mounted with high precision by passive alignment.

In the second method of forming an optical block according to the present invention, preferably, (b) is performed during the step (a).
It is good to carry out the process.

In practicing the present invention, it is preferable that the dicing mark is formed at the position of each vertex of a square surrounding the computer hologram and at the same distance from the optical axis of the computer hologram.

In practicing the present invention, it is preferable to form a metal mark as the dicing mark.

In practicing the present invention, it is preferable that the dicing marks also serve as reference marks for positioning each other when a plurality of transparent substrates are laminated.

(Optical Block) According to the optical block of the present invention, the transparent substrate on which the computer generated hologram (CGH element) and the dicing mark are formed is diced along the dicing mark to form a region including the CGH element. An optical block cut out,
The dicing mark is formed using a photolithography technique.

As described above, according to the optical block of the present invention, the dicing marks are formed using the photolithography technique. Therefore, the distance from the optical axis of the optical block to the position of the dicing mark can be accurately determined. Since the dicing is performed along the dicing marks, the optical block of the present invention has a high precision in the position of the cut surface formed by dicing from the optical axis. That is, the position of the cut surface as the side surface of the optical block can be accurately determined.

Therefore, if the cut surface is brought into contact with the mounting object and the optical block is mounted, the optical block can be mounted with high precision by passive alignment.

In the optical block of the present invention,
Preferably, the optical block is cut out from a stacked substrate group in which the transparent substrates are stacked on each other by dicing along a dicing mark as a plurality of stacked ume substrate blocks.

As described above, by dicing the laminated substrate group in which the transparent substrates on which the CGH elements are respectively formed are laminated, an optical block in which a plurality of transparent substrate blocks on which the CGH elements are respectively formed is laminated.

Further, in the optical block of the present invention,
Preferably, the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of transparent substrates are laminated.

In implementing the optical block of the present invention, preferably, the dicing mark is a position of a vertex of a square surrounding each CGH element, and
It is preferable that the H element be formed at a position equidistant from the optical axis of the H element.

In practicing the present invention, preferably, the dicing mark is a metal mark.

[0071]

Embodiments of the present invention will be described below with reference to the drawings. The drawings to be referred to are
Only the size, shape and arrangement of each component are schematically shown to the extent that the present invention can be understood. Therefore, the present invention is not limited to the illustrated example.

(First Embodiment) In the present invention, first, a photolithography technique is used to form a transparent substrate on a transparent substrate.
A computer generated hologram (CGH element) and a dicing mark are formed.

Therefore, in this embodiment, a plurality of CGH elements are formed on a quartz transparent substrate by using ordinary photolithography technology. In this embodiment, when forming a CGH element, a dicing mark is also formed at the same time using photolithography technology.

In performing photolithography, a conventionally well-known technique may be used. For example, first
A photoresist (not shown) and a metal film (not shown) are sequentially laminated on a transparent substrate. Next, a mask pattern of a CGH element and a mask pattern of a dicing mark are drawn on the metal film using electron beam lithography to form a metal mask pattern. Next, by exposing the photoresist through this metal mask pattern, the metal mask pattern is transferred to the photoresist to form a resist pattern. Next, the CGH element 12 and the dicing mark 14 are formed by etching the transparent substrate 10 using this resist pattern as an etching mask, as shown in FIG. The optical axis of each CGH element 12 is
Are formed in a direction perpendicular to the upper surface on which these elements are formed.

FIG. 1 (A) shows a plurality of CGH elements 12 and dicing marks 1 on an upper surface of a quartz transparent substrate 10.
4 shows a state in which each is formed. In this embodiment, as shown in FIG. 1A, the contour of each CGH element 12 is circular. In this configuration example, each CGH element 1
2 are arranged in a matrix, and dicing marks are arranged at four points around each of the CGH elements 12 so as to be in a matrix position as a whole. Further, the dicing mark 14 is a cross-shaped groove or projection. Since these dicing marks 14 are formed by using the photolithography technique, they can be formed accurately at the designed positions.

Further, instead of forming the dicing mark 14 by etching the transparent substrate 10,
Alternatively, a metal mark may be provided using photolithography technology, and this mark may be used as the dicing mark 14.
In forming the metal mark, for example, the transparent substrate 10
An aluminum layer (not shown) is formed by evaporating aluminum (Al) on the entire surface of the main surface of
That is, portions other than the dicing marks may be removed by wet etching.

The metal mark can be formed by another method. For example, after covering a portion of the main surface of the transparent substrate 10 where no dicing mark is formed with a photoresist pattern (not shown), a metal is deposited on the portion of the transparent substrate 10 exposed from the resist pattern. A metal mark may be formed.

In this embodiment, the dicing mark 14 is formed at each vertex of a square surrounding each CGH element 12 and at the same distance from the optical axis of the CGH element 12. Here, with reference to FIGS. 1B and 1C, an arrangement relationship between the dicing mark 14 and the CGH element 12 will be described focusing on one CGH element 12. FIG. FIG. 1B is an enlarged view showing a part of the upper surface of the transparent substrate 10 shown in FIG. FIG. 1C is a perspective view showing a part of the transparent substrate 10 shown in FIG.

FIG. 1B and FIG. 1C show
One CGH element 12 and four cross-shaped dicing marks 14 surrounding it are shown. The four dicing marks 14 are located at the vertices of a square (indicated by a dotted line S in FIG. 1B) surrounding the CGH element 12. The intersection A between the diagonal lines C1 and C2 of the square S coincides with the optical axis of the CGH element 12. The length of one side of the square S is expressed by the following equation.
It is about 00 μm to 2 mm.

Next, the processed transparent substrate 1 on which the CGH element 12 and the dicing mark 14 have been formed, respectively.
0 is diced along the dicing mark 14.
Dicing individually along the dicing mark 14 means that the dicing marks 1 arranged in the row direction and the column direction are used.
This refers to dicing in a row direction and a column direction along a straight line connecting the intersections of the crosses 4. Then, by this dicing, optical blocks each including the CGH element 12 are cut out. In this embodiment, a normal dicing saw is used for dicing. Further, the cut surface of the optical block is a flat surface because it is a cut surface by a dicing saw.

In the present invention, not only the optical block is cut out from only one processed transparent substrate 10 as described above, but also the optical block is formed from a laminated substrate group in which a plurality of processed transparent substrates are stacked. You may cut it out.

In this case, after forming the processed transparent substrate 10 on which the CGH element 12 and the dicing mark 14 are respectively formed, first, a plurality of processed transparent substrates 10 are stacked on each other to form a stacked substrate group. I do. In this embodiment, when laminating the transparent substrates 10, the respective transparent substrates 10 are aligned using the dicing marks 14 as arrangement marks. By this alignment, the optical axes of the CGH elements 12 formed on the different transparent substrates 10 are made to coincide with each other.

Here, FIG. 2A shows a laminated substrate group 16 in which three transparent substrates 10 are laminated. In FIG. 2A, the transparent substrates 10 are shown separated from each other to facilitate understanding of the configuration of the laminated substrate group 16. In FIG. 2A, the C formed on each transparent substrate 10 is shown.
The GH element 12 and the dicing mark 14 are shown as a lattice shape for convenience.

Next, the laminated substrate group 16 is diced along the dicing marks 14 so that
An optical block 20 in which a plurality of transparent substrate blocks on which the GH elements 12 are formed is cut out.

FIG. 2B is a perspective view of the optical block 20 cut out by dicing. FIG.
As shown in (B), the optical block 20 is configured by stacking three transparent substrate blocks 10a.
One CGH element 12 is formed on each transparent substrate block 10a. Each transparent substrate block 10a is bonded so that the optical axes 22 of the respective CGH elements 12 coincide with each other.

Since the optical block 20 is cut along the dicing mark 14 accurately formed by using the photolithography technique, the cut surface 24 which is the side surface of the optical block 20 and the optical axis 20 are cut. The separation distance between them is substantially accurately formed as designed. In this embodiment, since the distance between the optical axis 22 of the CGH element 12 and the four side surfaces 24 is equal to each other, any of the four flat side surfaces can be used as a surface that comes into contact with the reference surface.

In FIGS. 2A and 2B, the surface of the transparent substrate 10 on which the CGH element 12 is formed is
Although the transparent substrates 10 are stacked in one direction, the optical blocks may be cut out by stacking the transparent substrates 10 with the surfaces on which the CGH elements 12 are formed facing each other in the present invention. .

Next, one of the cut surfaces of the optical block by dicing is brought into contact with the reference surface, so that the optical block is set on the flat mounting substrate.

Here, FIGS. 3A and 3B show an example of a planar mounting substrate. FIG. 3A is a side view of the planar mounting substrate 26 used in this embodiment. FIG. 3B is a top view of the planar mounting substrate 26. Further, in this embodiment, the planar mounting substrate 2
As 6, a silicon terrace made of silicon is used.

The planar mounting substrate 26 has a reference surface 28 provided one step lower on the upper surface. This reference plane 2
Preferably, the size of the optical block 20a is such that the optical block 20a fits without rattling.
May be loosely fitted. A groove (V-shaped groove) 30 having a V-shaped cross section for fixing the optical fiber is provided on the surface of the terrace on one side adjacent to the reference surface. The V-shaped groove 30 is provided at the center in the width direction of the planar mounting substrate 26 along a direction from one end of the planar mounting substrate 26 toward the reference surface 28 side.

Next, FIGS. 3C and 3D show that the optical block 20 is placed on the reference surface 28 of the planar mounting substrate 26.
3 shows a state in which a is mounted. FIG. 3C is a side view of the planar mounting substrate 26 and the optical block 20a mounted thereon. FIG. 3D is a top view of the planar mounting substrate 26 and the optical block 20a.

The optical block 20a shown in FIGS. 3C and 3D is formed in the same manner as the optical block 20 described above. Therefore, the side surface 24a of the optical block 20a is also formed with high positional accuracy from the optical axis of the optical block 20a.

The optical block 20a is obtained by laminating two transparent substrate blocks 10a such that the surfaces on which the CGH elements 12 are formed face each other.

Then, one of the side surfaces 24a, which is the cut surface of the optical block 20a, is connected to the reference surface 28 of the planar mounting substrate 26.
By mounting the optical block 20a in contact with the reference surface 28, the reference plane 28 can be mounted without any degree of freedom in the vertical direction. In addition, since the accuracy of the position of the side surface 24a with respect to the optical axis of the optical block is good, the reference surface 28
The distance between the optical block 20a and the optical axis of the optical block 20a can be accurately determined. As a result, the optical block 20a can be mounted with high precision by passive alignment.

Further, an optical fiber 32 and a light receiver 34 are mounted on the planar mounting board 26 in addition to the optical block 20a as a free space optical wiring optical system. The light receiver 34 is installed on the other terrace upper surface 28a one step higher than the reference surface by flip chip bonding. The optical fiber 32 is mounted in the V-shaped groove 30. Therefore, the distance between the optical axis of the optical fiber 32 fixed to the V-shaped groove 30 and the reference surface 28 and the distance between the optical axis of the optical receiver and other optical elements mounted on the other terrace upper surface 28a and the reference surface 28 The distance between the optical block 2
The optical block 20a is designed so as to coincide with the distance between the optical axis of the optical block 0a and the cut surface of the optical block 0a.
a. The positioning of the optical fiber 32 and the light receiver 34 can be performed accurately and easily. That is, since the optical axis of the optical fiber 32, the optical axis of the optical block 20a, and the optical axis of the light receiver 34 are aligned in a two-dimensional plane, the respective optical axes can be easily aligned.

The CGH element 12 formed on the first-stage transparent substrate block 10a on the optical fiber side among the transparent substrate blocks 10a constituting the optical block 20a is:
It has the function of a so-called collimating lens that converts light divergent from a point light source into a parallel light flux. Accordingly, the divergent spherical wave emitted from the optical fiber 32 is converted into the first-stage CGH.
The light is once converted into a parallel light beam by the element 12. Also,
Of the transparent substrate blocks 10a constituting the optical block 20, the second-stage transparent substrate block 10a on the light receiver 34 side
The CGH element 12 has a function of condensing the parallel light beam incident from the first-stage transparent substrate block 10a on the light receiver 34.

The functions of the CGH elements 12 formed on the first-stage and second-stage transparent substrate blocks 10a can be collectively performed by one CGH element 12. However, as in this embodiment, two C
When the function is assigned to the GH element 12, the function is assigned to one CG
The coupling efficiency can be improved as compared with the case where the H elements 12 are integrated.

(Second Embodiment) Next, an example in which an optical system of an optical device for an optical communication terminal station is configured by using an optical block formed by the method of the present invention will be described. FIG.
FIG. 4 is a perspective view of an optical system according to a second embodiment.

FIG. 4 shows the reference surface 2 of the planar mounting substrate 26.
8 shows an optical system on which the optical block 40 is mounted. The optical block 40 is formed in the same manner as the optical blocks 20 and 20a in the first embodiment. Therefore, the side surface 38 of the optical block 40 also
The optical block 40 is formed with a high positional accuracy from the optical axis.

The optical block 40 is formed by stacking three transparent substrate blocks 42, 44 and 46. On the main surface of the first-stage transparent substrate block 42, a first CGH element 48 and a second CGH element 50 are formed, respectively. The third surface of the CGH element 52 is provided on the main surface of the second-stage transparent substrate block 44.
Are formed, and further, a wavelength selection filter 54 is formed on a main surface around the filter. In FIG. 4, the wavelength selection filter 54 is shaded for convenience. On the main surface of the third-stage transparent substrate block 46, a fourth CGH element 56 and a fifth CGH element 58 are formed, respectively. Then, this optical block 40
In this example, the transparent substrate blocks 42, 44 and 46 are stacked on each other with the direction of the main surface on which the CGH element is formed being aligned in one direction.

The optical block 40 is placed on the planar mounting board 26 by bringing one of the side walls 38 into contact with the reference plane 28. In this embodiment, the optical block 40 is provided with each transparent substrate block 4.
The main surfaces formed of the CGH elements 2, 44, and 46 are mounted facing the light receiver 34 and the light emitter 36 (FIG. 4).

As described above, by mounting the optical block 40 by bringing the side surface 38, which is the cut surface, into contact with the reference surface 28 of the planar mounting substrate 26, the degree of freedom in the vertical direction is eliminated from the contacted reference surface 28. Thus, the optical block 40 can be mounted. In addition, the accuracy of the position of the side surface 38 is good, so that the distance between the reference surface 28 and the optical axis of the optical block 40 can be accurately determined. As a result, the optical block can be accurately mounted by passive alignment.

In addition to the optical block 40 as a free-space optical wiring optical system, the planar mounting substrate 26
Optical fiber 32, a photodiode (PD) 34 as a light receiver, and a semiconductor laser (L
D) 36 is implemented. The light receiver 34 and the light emitter 36 are fixed to the terrace upper surface 28a one step higher than the reference surface by flip chip bonding. One of the two optical fibers 32 is connected to an input terminal, and the other is connected to an output terminal. The two optical fibers 32 are individually mounted in the V-shaped grooves 30, respectively.

Therefore, in this embodiment, the optical block 40, the optical fiber 32, the light receiver 34, and the light emitter 36
Can be accurately and easily performed.

Next, the function of the optical block shown in FIG. 4 will be described with reference to FIG. FIG. 5 is a diagram for explaining the function of the optical system according to the second embodiment.

As shown in FIG. 5, the optical system according to the second embodiment has a function as an optical device for an optical communication terminal. In this optical device, an optical signal having a wavelength of 1.3 μm and an optical signal having a wavelength of 1.5 μm are wavelength-multiplexed from an input terminal, and a wavelength-multiplexed optical signal is input. An optical signal having a wavelength of 1.3 μm is
For example, it is used to propagate audio information. An optical signal having a wavelength of 1.5 μm is used, for example, for transmitting video information.

The wavelength division multiplexed optical signal input to the optical device is split into a 1.3 μm wavelength optical signal and a 1.5 μm wavelength optical signal in a wavelength demultiplexer. The demultiplexed optical signal having a wavelength of 1.5 μm is output to the output terminal.
The demultiplexed optical signal having a wavelength of 1.3 μm is input to the optical coupler. 1.3 wavelength input to the optical coupler
The optical signal of μm is input to the light receiver 34. The 1.3 μm wavelength optical signal output from the light emitter 36 is output to the input terminal via the optical coupler and the wavelength demultiplexer.

In the optical device for an optical communication terminal station shown in FIG. 5, a portion surrounded by a broken line, that is, a function equivalent to the wavelength demultiplexing element and the optical coupler is provided by the optical block 40.
Has. The optical block 40 has a light collecting function and a collimating lens function in addition to the above.

Next, the function of each CGH element provided in each of the transparent substrate blocks 42, 44 and 46 constituting the optical block 40 will be described.

The first CGH element 48 formed on the first-stage transparent substrate block 42 converts a divergent spherical wave composed of a wavelength-division multiplexed optical signal incident on the optical block from the input terminal via the optical fiber 32 into a parallel light flux. Has a collimating function. Further, the first CGH element 48 has a deflecting function of directing the parallel light beam to the wavelength selection filter 54 formed on the second-stage transparent substrate block 44.

The wavelength selection filter 54 is a dielectric filter composed of a dielectric multilayer film. The wavelength selection filter 54 outputs the wavelength 1.x of the wavelength multiplexed optical signal.
A 5 μm optical signal is selectively reflected, while a wavelength of 1.3 μm.
m optical signals are selectively transmitted.

The optical signal having a wavelength of 1.5 μm reflected by the wavelength selection filter 54 is transmitted to the first-stage transparent substrate block 4.
The light is condensed on the optical fiber 32 connected to the output terminal by the second CGH element 50 formed in FIG. Then, the optical signal having a wavelength of 1.5 μm collected on the optical fiber is output to an output terminal.

On the other hand, the optical signal having a wavelength of 1.3 μm transmitted through the wavelength selection filter 54 is transmitted to the second-stage transparent substrate block 4.
By the third CGH element 52 formed in No. 4, about 40% of the light is deflected toward the fourth CGH element 56 as -1st-order diffracted light.

The fourth CGH element 56 formed on the third-stage transparent substrate block 46 has a light-condensing function of condensing the deflected parallel light flux of the 1.3 μm optical signal toward the light receiver 34. Have. Then, the collected 1.3 μm optical signal is detected by the light receiver 34.

The optical signal having a wavelength of 1.3 μm emitted from the semiconductor laser as the light emitter 36 is supplied to the fifth CGH element 58 formed on the third-stage transparent substrate block 46.
Is converted into a parallel light beam by the third CGH element 52.
Is incident on. Then, the wavelength 1.
The 3 μm optical signal is output to the input terminal via the third CGH element 52, the first CGH element 48, and the optical fiber 32.

As described above, the optical system according to the second embodiment performs one-way communication for an optical signal having a wavelength of 1.5 μm.
An optical signal having a wavelength of 1.3 μm functions as an optical device for an optical communication terminal capable of performing bidirectional communication.

In each of the embodiments described above, only examples in which these inventions are configured using specific materials and under specific conditions have been described. However, these inventions can be subjected to many changes and modifications. For example, in the above-described embodiment, the dicing mark is formed at the same time when the CGH element is formed. However, in the present invention, the timing of forming the dicing mark does not need to be limited to this. For example, the dicing mark may be formed after forming the CGH element.
Further, for example, a dicing mark may be formed before forming a CGH element.

Further, for example, in the above-described embodiment,
Although the optical block is cut into a target shape with respect to the optical axis of the CGH element by dicing, the cutting method is not limited to this in the present invention. Further, in this embodiment, the positioning is performed so that the optical axis of the optical fiber and the optical axis of the optical block coincide with each other. However, in the present invention, the optical axes do not always need to coincide with each other. For example, it may be mounted as a so-called off-axis type.

Further, for example, in the above-described embodiment, the example of the planar mounting substrate in which the reference surface is one step lower than the upper surface has been described. However, in the present invention, the shape of the planar mounting substrate needs to be limited to this. However, it is possible to use a planar mounting substrate having any suitable shape. For example, a planar mounting substrate having a reference surface at the same height as the upper surface may be used.

For example, in the above-described embodiment, an example of an optical block in which a plurality of transparent substrate blocks are stacked has been described. However, in the present invention, an optical block in which a plurality of transparent substrate blocks are stacked is described. It is not necessary to limit to. For example, a CGH element formed on one transparent substrate cut out by dicing may be used as an optical block.

For example, in the above-described embodiment,
Although the example in which the dicing mark also serves as the alignment mark has been described, in the present invention, the alignment mark may be formed separately from the dicing mark. In that case,
The number of alignment marks may be smaller than the number of dicing marks.

For example, in the above-described embodiment,
Although an example in which a cross-shaped mark is formed as the dicing mark has been described, in the present invention, the shape of the dicing mark is not limited to this, and a dicing mark having any suitable shape can be formed.

For example, in the above-described embodiment,
Although a quartz substrate was used as the transparent substrate, in the present invention, the material of the transparent substrate is different from the light source wavelength used by the optical system.
Any material may be used as long as the loss of transmitted light is sufficiently small and a CGH element can be formed. For example, a silicon substrate may be used as the transparent substrate.

Further, for example, in the above-described embodiment,
When an optical block is cut out from a laminated body in which a plurality of transparent substrates are laminated, a CGH element and a dicing mark are formed on each transparent substrate. In the present invention, however, a CGH element and a dicing mark are formed on all the laminated transparent substrates. For example, a transparent substrate on which only a CGH element is formed is laminated on a processed transparent substrate on which a CGH element and a dicing mark are formed to form a laminated substrate group as a dicing target, for example. You may.

[0125]

According to the present invention, a dicing mark is formed using a photolithography technique. Therefore, the position of the dicing mark can be accurately determined. Since the dicing is performed along the dicing mark, the position of the cut surface formed by the dicing has high accuracy. That is, the side surface as the cut surface of the optical block can be formed with high positional accuracy.

Then, the cut surface is brought into contact with the reference surface of the planar mounting substrate, and the optical block is mounted.
The optical block can be mounted without the degree of freedom in the direction perpendicular to the reference plane. In addition, since the accuracy of the position of the cut surface is good, the distance between the reference surface and the optical axis of the optical block can be accurately determined. As a result, the optical block can be easily and accurately mounted by the passive alignment.

[Brief description of the drawings]

FIG. 1A is a top view of a transparent substrate, and FIG.
3 is an enlarged top view of the transparent substrate, and FIG. 3C is a perspective view of a part of the transparent substrate.

FIG. 2A is a diagram for explaining a laminated substrate group, and FIG. 2B is a perspective view of an optical block.

FIG. 3A is a side view of a planar mounting substrate,
(B) is a top view of the planar mounting substrate, and (C) is
It is a side view of the board for planar mounting in which the optical block was mounted, and (D) is a top view of the board for planar mounting in which the optical block was mounted.

FIG. 4 is a perspective view for explaining an optical system according to a second embodiment;

FIG. 5 is a diagram for explaining functions of an optical device for an optical communication terminal station in an optical system according to a second embodiment;

[Explanation of symbols]

 Reference Signs List 10: transparent substrate 10a: transparent substrate block 12: CGH element 14: dicing mark 16: laminated substrate group 20, 20a: optical block 22: optical axis 24, 24a: side surface, cut surface 26: substrate for planar mounting 28: reference surface 28a: Terrace upper surface 30: V-shaped groove 32: Optical fiber 34: Light receiver (photodiode) 36: Light emitter (semiconductor laser) 38: Side surface 40: Optical block 42, 44, 46: Transparent substrate block 48, 50, 52 , 56, 58: CGH element 54: Wavelength selection filter

Claims (35)

[Claims] 1. An optical block mounting method for mounting an optical block on a planar mounting substrate having a reference surface, comprising: (a) forming a computer generated hologram on a transparent substrate by using photolithography technology; (B) forming a dicing mark on the transparent substrate in a specific positional relationship with the computer hologram using photolithography technology; and (c) forming the computer hologram and the dicing mark. Dicing the processed transparent substrate along the dicing mark to cut out an optical block including the computer generated hologram; and (d) at least one of the cut surfaces of the optical block obtained by dicing is defined by the reference By contacting the surface
Mounting the optical block on the substrate for planar mounting. 2. The method for mounting an optical block according to claim 1, wherein the step (b) is performed during the step (a). 3. The method for mounting an optical block according to claim 1, wherein the dicing mark is formed at each vertex of a square surrounding the computer hologram and at a position equidistant from the optical axis of the computer hologram. A method of mounting an optical block. 4. The method of mounting an optical block according to claim 1, wherein a metal mark is formed as the dicing mark. 5. The method for mounting an optical block according to claim 1, wherein a silicon terrace is used as the planar mounting substrate. 6. The method of mounting an optical block according to claim 1, wherein the step (c) comprises: (c1) laminating a plurality of the processed transparent substrates to form a laminated substrate group; (C2) dicing the group of laminated substrates along the dicing mark to cut out the optical block. 7. The method for mounting an optical block according to claim 6, wherein the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of the transparent substrates are stacked. How to mount optical blocks. 8. An optical block mounting method for mounting an optical block on a planar mounting substrate having a reference surface, comprising: (a) forming a computer generated hologram on a transparent substrate by using a photolithography technique; (B) forming a dicing mark on the transparent substrate in a specific positional relationship with the computer hologram using photolithography technology; and (c) forming the computer hologram and the dicing mark. (D) dicing the laminated substrate group along the dicing mark to form a laminated transparent substrate including the computer generated hologram. Cutting out an optical block composed of a substrate block; and (e) reducing the cut surface of the optical block by dicing. The Kutomo one by contacting to the reference plane,
Mounting the optical block on the substrate for planar mounting. 9. The method of mounting an optical block according to claim 8, wherein the step (b) is performed during the step (a). 10. The method for mounting an optical block according to claim 8, wherein the dicing mark is formed at each vertex of a square surrounding the computer hologram and at a position equidistant from the optical axis of the computer hologram. A method of mounting an optical block. 11. The method for mounting an optical block according to claim 8, wherein a metal mark is formed as the dicing mark. 12. The method for mounting an optical block according to claim 8, wherein a silicon terrace is used as the planar mounting substrate. 13. The method for mounting an optical block according to claim 8, wherein the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of the transparent substrates are stacked. How to mount optical blocks. 14. On a planar mounting substrate having a reference surface,
An optical system mounted with an optical block, wherein the optical block is cut out from a transparent substrate on which a computer generated hologram and a dicing mark are formed, as a region including the computer generated hologram, by dicing along the dicing mark. An optical system in which an optical block is mounted, wherein the dicing mark is formed using a photolithography technique. 15. The optical system in which the optical block according to claim 14 is mounted, wherein the dicing mark is a position of each vertex of a square surrounding the computer hologram, and a position equidistant from an optical axis of the computer hologram. An optical system having an optical block mounted thereon. 16. An optical system mounted with the optical block according to claim 14, wherein the dicing mark is a metal mark. 17. An optical system in which the optical block according to claim 14 is mounted, wherein the substrate for planar mounting is a silicon terrace. 18. The optical system in which the optical block according to claim 14 is mounted, wherein each of the optical blocks is formed by a computer from a group of laminated substrates on which the transparent substrates are laminated by dicing along the dicing mark. An optical system mounted with an optical block, wherein the optical block is cut out as a structure in which a transparent substrate block including a hologram is laminated. 19. The optical system in which the optical block according to claim 18 is mounted, wherein the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of the transparent substrates are stacked. An optical system equipped with the characteristic optical block. 20. A step of forming a computer generated hologram on a transparent substrate using a photolithography technique; and (b) a step of forming the computer generated hologram on a transparent substrate using a photolithography technique. Forming a dicing mark in a relation; and (c) dicing the computer-generated hologram and the processed transparent substrate on which the dicing mark has been formed along the dicing mark, thereby forming an optical block including the computer-generated hologram. And a cutting step. 21. The method for forming an optical block according to claim 20, wherein the step (b) is performed during the step (a). 22. The method of forming an optical block according to claim 20, wherein the dicing mark is positioned at each vertex of a square surrounding the computer hologram and at a position equidistant from the optical axis of the computer hologram. A method for forming an optical block, comprising: forming an optical block; 23. The method of forming an optical block according to claim 20, wherein a metal mark is formed as the dicing mark. 24. The method of forming an optical block according to claim 20, wherein the step (c) comprises: (c1) laminating a plurality of the processed transparent substrates together to form a laminated substrate group. (C2) a step of cutting out the optical block by dicing the laminated substrate group along the dicing mark. 25. The method for forming an optical block according to claim 24, wherein the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of the transparent substrates are stacked. Of forming an optical block. 26. (a) forming a computer generated hologram on a transparent substrate by using photolithography technology; and (b) forming the computer generated hologram on the transparent substrate by using photolithography technology. (C) laminating the computer-generated hologram and the processed transparent substrate on which the dicing mark has been formed to form a laminated substrate group; and (d) forming the laminated substrate group. Dicing along the dicing mark to cut out optical blocks each comprising a laminated transparent substrate block including the computer generated hologram. 27. The method of forming an optical block according to claim 26, wherein the step (b) is performed during the step (a). 28. The method for forming an optical block according to claim 26, wherein the dicing mark is positioned at each vertex of a square surrounding the computer hologram and at a position equidistant from the optical axis of the computer hologram. A method for forming an optical block, comprising: forming an optical block; 29. The method for forming an optical block according to claim 26, wherein a metal mark is formed as the dicing mark. 30. The method of forming an optical block according to claim 26, wherein the dicing mark also serves as an alignment mark that serves as a reference for alignment when a plurality of the transparent substrates are stacked. Of forming an optical block. 31. An optical block cut out from a transparent substrate on which a computer generated hologram and a dicing mark are formed as a region including the computer generated hologram by dicing along the dicing mark, wherein the dicing mark is formed by photolithography. An optical block characterized by being formed using technology. 32. The optical block according to claim 31, wherein the dicing mark is a position of each vertex of a square surrounding the computer generated hologram and formed at a position equidistant from an optical axis of the computer generated hologram. An optical block, characterized in that: 33. The optical block according to claim 31, wherein the dicing mark is a metal mark. 34. The optical block according to claim 31, wherein the optical block includes a transparent substrate including the computer generated hologram by dicing along the dicing mark from a laminated substrate group in which the transparent substrates are laminated. An optical block, wherein the block is cut out as a laminated structure. 35. The optical block according to claim 34, wherein the dicing mark also serves as an arrangement mark serving as a reference for mutual alignment when a plurality of the transparent substrates are stacked. .