JP3911816B2 - Optical transmission line forming method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical transmission path forming method for forming an optical transmission path for performing optical transmission by connecting optical transmission ends, and an optical transmission circuit formed by the method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an electronic circuit connection method using electric wiring is well known. However, in recent years, with the increase in circuit processing speed, delays and waveform distortion are likely to occur in electrical wiring, and accurate signal transmission cannot be performed. Therefore, electrical signals are converted to light and signals are transmitted through optical wiring. So-called optical interconnection technology has been devised. However, the optical interconnection technology requires a high accuracy of several μm or less for optical axis alignment for coupling between the light emitting element and the light receiving element or the optical waveguide, so that there is a problem that mounting assembly is difficult.
[0003]
In addition, as a method of connecting the optical waveguide to a light emitting element or the like, a non-contact type optical coupler is proposed in which light is propagated in space and is indirectly connected instead of being directly coupled. However, in such a non-contact type optical coupler, it is necessary to reduce the coupling loss by processing the end of the optical fiber facing the light emitting portion into a lens shape, so that the mounting (positioning) process is more complicated. There is a problem of becoming.
[0004]
In the conventional optical connection method between the optical fiber and the light receiving / emitting element, the light receiving / emitting surface of the light receiving / emitting element is on the upper surface of the element, and the optical axis of the incident light from above or the optical axis of the emitted light upward The end of the optical fiber is cut at 45 degrees and polished to connect the optical axis of the optical fiber and the optical axis of the light receiving / emitting element for the purpose of controlling the rotation around the optical axis of the optical fiber. Since it is necessary to simultaneously control the XYθ3 axes, the alignment cost is bulky and occupies most of the mounting cost.
[0005]
In order to solve this problem, JP-A-1-269903 and JP-A-5-88028 devise a system for optical coupling by directly connecting an optical fiber to an element by a wire bonding system. .
However, in the conventional optical semiconductor device, an optical fiber is used to form an optical transmission path between the optical signal transmission ends which are optical signal transmission ends or reception ends. However, the optical fiber does not have the flexibility to bend freely between several μm to several mm like the wire bonding. When the fiber is bent, the optical fiber is broken at the bent portion, and optical connection is virtually impossible. Even if the connection can be made by wire bonding without breaking, shear stress is always applied to the optical transmission end, that is, the joint between the light emitting element and the light receiving element or the optical waveguide. There is also a problem in terms of reliability because there is a large risk of adhesion peeling at the part.
[0006]
Japanese Patent Publication No. 8-12303 discloses a method of forming an optical waveguide between chips by extruding a polymer of an optical waveguide material from a nozzle.
However, this publication does not disclose a specific method relating to the connection between the chip and the optical waveguide when the optical waveguide is formed on the chip. In practice, it is considered extremely difficult to align the optical axis of the optical waveguide at the end face of the chip while forming the optical waveguide by extruding the polymer from the nozzle above the chip. Further, according to the drawings described in the above publication, in order to connect the optical waveguide to the end face of the chip, the optical waveguide must be bent in an L shape. If there is an L-shaped bent portion, light may escape from the L-shaped bent portion and light transmission through the optical waveguide may become impossible.
[0007]
[Problems to be solved by the invention]
In view of the above circumstances, the present invention provides an optical transmission line that can form an optical transmission line without causing breakage or residual shear stress when forming an optical transmission line between optical transmission ends. It is an object of the present invention to provide a method and an optical transmission circuit formed based on the method.
[0008]
[Means for Solving the Problems]
The method of forming an optical transmission line of the present invention that achieves the above object is as follows.
In an optical transmission line forming method of forming an optical transmission path between optical transmission ends of an optical transmission path formed body having an optical transmission end connected by an optical transmission path and performing optical transmission via the optical transmission path,
A void having the same shape as the optical transmission path support for supporting the optical transmission path is formed between the optical transmission path formation body and the optical transmission path formation body. A first step of forming the optical transmission path support by placing a mold and injecting a solidified optical transmission path support base forming material in a fluid state into the void;
On the optical transmission path support base, a second mold is formed in which a cavity having the same shape as the optical transmission path is formed between the optical transmission path support base and the cavity is placed in the cavity. And a second step of forming an optical transmission line by injecting a solidifying optical transmission line forming material in a fluidized state.
[0009]
The optical transmission circuit of the present invention that achieves the above object is
An optical transmission line forming body having a plurality of optical transmission ends which are optical signal transmission or reception terminals;
An optical transmission line connecting a plurality of optical transmission ends;
An optical transmission path support base that supports the optical transmission path, which is formed between the optical transmission path forming body and the optical transmission path, is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a perspective view showing an optical transmission line forming body before an optical transmission line is formed by the optical transmission line forming method of the present invention.
FIG. 1 shows a substrate 1 which is an optical transmission path forming body on which an optical transmission path is formed, optical / electronic integrated circuits 2a and 2b and an electronic integrated circuit 2c mounted on the substrate 1, and optical / electronic integration. Optical waveguides 6a and 6b having optical transmission ends 8a, 8b, 8c and 8d at both ends for optical transmission between the circuits 2a and 2b are shown.
[0011]
The substrate 1 is made of glass, LiNbO ₃ or the like, and the optical / electronic integrated circuits 2a, 2b and the electronic integrated circuit 2c are made of a Si wafer or a GaAs wafer. On the optical / electronic integrated circuits 2a and 2b, light emitting elements 3a and 3b, light receiving elements 4a and 4b, and electronic circuits 5a and 5b for driving these elements to perform signal processing are formed. An electronic circuit 5v that performs signal processing is formed on the electronic integrated circuit 2c.
[0012]
On the substrate 1, electrical wiring 7 is formed for electrical connection between the optical / electronic integrated circuits 2a, 2b and the electronic integrated circuit 2c. The electric wiring 7 is an electronic circuit 5a, 5b formed on the optical / electronic integrated circuits 2a, 2b and an electron formed on the electronic integrated circuit 2c by a wire 9 made of a gold wire or the like formed by wire bonding. The circuit 5c is connected, and the electronic circuits 5a, 5b, 5c are electrically coupled.
[0013]
FIG. 2 is a schematic configuration diagram showing an embodiment of an optical transmission line forming apparatus used in the optical transmission line forming method of the present invention.
This optical transmission line forming apparatus is provided with a support base 100, on which a substrate mounting base on which the optical / electronic integrated circuits 2 a and 2 b and the substrate 1 on which the electronic integrated circuit 2 c is mounted is placed. 101 is provided.
[0014]
Further, on the support base 100, an X-direction drive unit comprising a slider 103 slidable in the arrow X direction along the guides 102a and 102b, a ball screw 104 for moving the slider 103 in the X direction, and a servo motor 105. 106 is provided. By rotating and driving the ball screw 104 by the servo motor 105, the slider 103 can be moved in the arrow X direction at a speed and a distance corresponding to the rotation speed and the rotation speed.
[0015]
A Y-direction drive unit 108 having a servo motor 107, a guide (not shown), a ball screw, and a slider and slidable in the arrow Y direction is attached to the slider 103. By rotating and driving a ball screw (not shown) by the servo motor 107, the Y-direction drive unit 108 itself can be moved in the Y direction at a speed and a distance corresponding to the rotation speed and the number of rotations.
[0016]
In addition, at the end of the Y-direction drive unit 108 on the substrate mounting table 101 side, a slider 109 slidable in the Z direction along a guide (not shown), and coupled to the slider 109, the slider 109 is moved in the Z direction. A Z-direction drive unit 111 including a ball screw and a servo motor 110 is provided. By rotating and driving a ball screw (not shown) by the servo motor 110, the slider 109 can be moved in the Z direction at a speed and a distance corresponding to the rotation speed and the rotation speed.
[0017]
The slider 109 is held by a support column 112, and a camera 113 that captures the image of the surface of the substrate 1 by photographing the substrate 1 from above, a mold mounting portion 118, and an optical transmission mounted on the mold mounting portion 118. A first mold 10 for a path support (or a second mold 20 for forming an optical transmission path) and a solidified optical transmission path support base forming material (or an optical transmission path forming material) in a fluid state The first material transfer part 115a and the first syringe 114a (or the second material transfer part 115b and the second syringe 114b) for supplying the liquid into the first mold 10 (or the second mold 20) ) And are attached.
[0018]
Among these, the first combination of the first mold 10, the first material transfer unit 115a, and the first syringe 114a is an optical transmission path in the first step in the optical transmission path forming method described later. The second combination of the second mold 20, the second material transfer unit 115b, and the second syringe 114b, which is used when forming the support base, transmits light in the second step. It is used when forming a path. These two types of combinations have a structure that can be interchanged depending on the process.
[0019]
Further, the optical transmission line forming apparatus is provided with a control unit 116 for controlling the entire apparatus. The control unit 116 is connected to the servo motors 105, 107, and 110 of the X direction driving unit 106, the Y direction driving unit 108, and the Z direction driving unit 111, and the servo motor of the camera 113 by the control wiring 120. The control unit 116 reads the positions of alignment markers (not shown) on the substrate 1 and the optical / electronic integrated circuits 2a, 2b from the image information input from the camera 113, and the control unit 116 reads the positions of the substrate 1 and the optical / electronic integrated circuits 2a, 2b. A function for calculating the positional deviation, a function for correcting the movement command data of the mold position determination program that has been input in advance from the calculated result, and the rotation speed and rotation of each servo motor based on the corrected movement command data And the function of controlling the number.
[0020]
Since this optical transmission line forming apparatus is configured as described above, based on a command from the control unit 116, the servo motor 105 of the X direction driving unit 106, the servo motor 107 of the Y direction driving unit 108, and the Z direction driving unit. By rotating and driving the servo motor 110 of 111, the camera 113, the first or second mold 10, 20, and the first or second syringe 114a, 114b at a speed and locus corresponding to the rotation speed and the rotation speed. , And the first or second material transfer section 115a, 115b can be freely moved in the three-dimensional directions of X, Y, and Z.
[0021]
FIG. 3 is a schematic process diagram showing an embodiment of the first process in the optical transmission line forming method of the present invention.
In FIG. 3, by connecting a light emitting element 3a disposed on the optical / electronic integrated circuit 2a mounted on the substrate 1 and an optical transmission end 8a formed on the substrate 1, these two optical transmissions are connected. A part of the embodiment of the first step in the optical transmission line forming method for forming the optical transmission line between the ends is shown.
[0022]
This first step is a step of forming an optical transmission path support base 12 for supporting the optical transmission path on the substrate 1 which is an optical transmission path formation body. A first mold 10 in which a cavity 11 having the same shape as the path support 12 is formed is placed, and a solidified optical transmission path support platform forming material in a fluid state is placed in the cavity 11. This is done by injection.
[0023]
The optical transmission path support base 12 supports the optical transmission path after the second step is completed and an optical transmission path is formed between the light emitting element 3a and the optical transmission end 8a shown in FIG. A cavity 21 having a function of holding the shape and having the same shape as the optical transmission path between the second mold 20 used when forming the optical transmission path in the second step ( It also has a function of forming (described later).
[0024]
In this step, the first mold 10, the first material transfer unit 115a, and the first syringe 114a are attached to the slider 109 in advance.
First, the X direction driving unit 106 (see FIG. 2), the Y direction driving unit 108, and the Z direction driving unit 111 of the optical transmission line forming apparatus are operated by a command from the control unit 116 based on image information input from the camera 113. The first mold 10 is positioned, and then the first mold 10 is placed on the substrate 1. As a result, optical transmission is performed between the first mold 10 and the substrate 1. A void 11 having the same shape as that of the optical transmission path support 12 for supporting the path is formed.
[0025]
Next, positioning of the first syringe 114a is performed, and then a predetermined amount of the light transmission path support base forming material in a fluid state supplied from the first material transfer unit 115a is in the first syringe 114a. And it inject | pours in the space 11 through the material injection hole 10a opened to the upper part of the 1st metal mold | die 10, and the space 11 is filled with the optical transmission-line support stand formation material.
[0026]
After the optical transmission path support base forming material injected into the void 11 is solidified, the first mold 10 is removed from the substrate 1, and the optical transmission having the same shape as the void 11 is formed on the substrate 1. A road support 12 is formed.
The optical transmission path support base forming material may be any material that is in a fluid state when injected into a mold and solidifies after injection. In particular, a casting material that does not require heating other than self-heating is suitable. Furthermore, it is desirable to use a black material having an effect of preventing optical noise.
[0027]
Next, a second step is performed.
FIG. 4 is a schematic process diagram showing an embodiment of the second process in the optical transmission line forming method of the present invention.
In FIG. 4, by connecting a light emitting element 3 a disposed on an optical / electronic integrated circuit 2 a mounted on the substrate 1 and an optical transmission end 8 a formed on the substrate 1, these two optical transmissions are performed. A part of the second step of the two steps in the optical transmission line forming method for forming the optical transmission line between the ends is shown.
[0028]
The second step is a step of forming the optical transmission path 22 on the optical transmission path support base 12 formed on the substrate 1 by the first process, and optical transmission between the optical transmission path support base 12 and the optical transmission path support base 12 is performed. By placing a second mold 20 in which a cavity 21 having the same shape as the path 22 is formed, and injecting a solidified optical transmission path forming material in a fluid state into the cavity 21 Done.
[0029]
In the second step, the second mold 20, the second material transfer unit 115 b, and the second syringe 114 b are attached to the slider 109 in advance.
First, the X direction driving unit 106 (see FIG. 2), the Y direction driving unit 108, and the Z direction driving unit 111 of the optical transmission line forming apparatus are operated by a command from the control unit 116 based on image information input from the camera 113. The second mold 20 is positioned, and then the second mold 20 is placed on the optical transmission path support base 12, and as a result, the second mold 10 and the optical transmission path support base 12 are placed. A space 21 having the same shape as the optical transmission line 22 is formed between the two.
[0030]
Next, positioning of the second syringe 114b is performed, and then, a predetermined amount of the optical transmission path forming material in a flow state supplied from the second material transfer unit 115b is supplied to the second syringe 114b and the second syringe 114b. The material is injected into the space 21 through the material injection port 20a opened at the top of the second mold 20, and the space 21 is filled with the optical transmission path forming material.
After the optical transmission path forming material injected into the void 21 is solidified, the second mold 20 is removed from the optical transmission path support base 12, and is identical to the void 21 on the optical transmission path support base 121. An optical transmission line 22 having the following shape is formed.
[0031]
In the present embodiment, a polymethyl methacrylate resin (refractive index: 1.49) having a high light transmittance is used as an optical transmission path forming material to be an optical transmission path. In addition to the above materials, the optical transmission path forming material is in a fluid state when injected into a mold and solidifies after injection and exhibits the same optical transmission property as the above material. Any other resin may be used. For example, cast polycarbonate resin is suitable.
[0032]
When it is necessary to form a clad on the surface of the optical transmission line 22, the clad can be formed by spraying a solidified clad material in a molten state after this step.
In the optical transmission line forming method of the present invention, the shape of the groove for forming the void corresponding to the optical transmission line formed on the inner surface of the second mold can be freely set. Thus, the shape and angle of the optical transmission path can be arbitrarily selected, and the efficiency and uniformity of optical transmission can be improved.
[0033]
In addition, the second mold includes a branching portion for branching an optical transmission line extending from one optical transmission end toward a plurality of optical transmission ends between the second mold and the optical transmission line support base. By using a mold in which a void having the same shape as the optical transmission line is formed, an optical transmission line having a branch point or a junction can be easily formed.
FIG. 5 is a schematic cross-sectional view of an optical transmission line formed by the optical transmission line forming method of the present invention.
[0034]
On the optical transmission line support base 12 formed on the substrate 1, the optical transmission line extends from the light emitting element 3 a on the optical / electronic integrated circuit 2 a mounted on the substrate 1 to the optical transmission end 8 a formed on the substrate 1. 22 is formed to be crosslinked.
The signal light 23 emitted from the light emitting element 3a is transmitted to the optical transmission end 8a via the optical transmission path 22, and optical transmission is performed.
[0035]
FIG. 6 is a schematic configuration diagram showing an embodiment of the optical transmission circuit of the present invention including the optical transmission path formed by the optical transmission path forming method of the present invention.
FIG. 6 shows a substrate 1 having a plurality of optical transmission terminals which are optical signal transmission or reception terminals, that is, light emitting elements 3a and 3b, light receiving elements 4a and 4b, and optical transmission terminals 8a, 8b, 8c and 8d. Optical transmission lines 22a, 22b, 22c, 22d for connecting the plurality of optical transmission terminals, optical / electronic integrated circuits 2a, 2b and electronic integrated circuit 2c mounted on the substrate 1, optical / electronic integrated circuit 2a, Each optical transmission path formed between the optical waveguides 6a and 6b having optical transmission ends 8a, 8b, 8c and 8d at both ends and the substrate 1 and each optical transmission path for performing optical transmission between 2b. An optical transmission circuit 30 including an optical transmission path support 12 for supporting the optical transmission line is shown.
[0036]
On the optical / electronic integrated circuit 2a, there are formed a light emitting element 3a, a light receiving element 4a, and an electronic circuit 5a for driving these elements to perform signal processing. Are formed with a light emitting element 3b, a light receiving element 4b, and an electronic circuit 5b for driving these elements to perform signal processing.
On the substrate 1, electrical wiring 7 is formed for electrical connection between the optical / electronic integrated circuits 2a, 2b and the electronic integrated circuit 2c. The electrical wiring 7 is connected to the electronic circuits 5a and 5b formed on the optical / electronic integrated circuits 2a and 2b and the electronic circuit 5c formed on the electronic integrated circuit 2c by a wire 9 formed by wire bonding. The electronic circuits 5a, 5b, 5c are electrically coupled.
[0037]
The optical transmission circuit 30 transmits and receives signal light between the light emitting elements 3a and 3b and the light receiving elements 4a and 4b via the optical waveguides 6a and 6b and the optical transmission paths 22a, 22b, 22c and 22d. Optical transmission is performed between the integrated circuits 2a and 2b.
Since signal processing can be performed in the electronic circuits 5a and 5b while performing high-speed data communication between the optical / electronic integrated circuits 2a and 2b using the optical transmission circuit 30, high-speed signal processing is consequently performed. Can do. The signal processing is controlled by the electronic integrated circuit 2.
[0038]
【The invention's effect】
As described above, according to the optical transmission path forming method of the present invention, after forming the optical transmission path support base that supports the optical transmission path on the optical transmission path formation body using the first mold, Since the optical transmission path is formed on the optical transmission path support using the second mold, no bent portion is formed in the optical transmission path, and therefore the optical transmission path is prevented from being broken at the bent portion. In addition, since no shear stress is applied to the optical transmission end, the occurrence of adhesion peeling is prevented.
[0039]
In addition, according to the optical transmission circuit of the present invention, it is possible to realize an optical transmission circuit that has good light transmission efficiency and small deterioration in transmission quality due to noise.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an optical transmission line forming body before an optical transmission line is formed by the optical transmission line forming method of the present invention.
FIG. 2 is a schematic configuration diagram showing an embodiment of an optical transmission line forming apparatus used in the optical transmission line forming method of the present invention.
FIG. 3 is a schematic process diagram showing an embodiment of a first process in the optical transmission line forming method of the present invention.
FIG. 4 is a schematic process diagram showing an embodiment of a second process in the optical transmission line forming method of the present invention.
FIG. 5 is a schematic cross-sectional view of an optical transmission line formed by the optical transmission line forming method of the present invention.
FIG. 6 is a schematic configuration diagram showing an embodiment of an optical transmission circuit of the present invention including an optical transmission line formed by the optical transmission line forming method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Board | substrate 2a, 2b Optoelectronic integrated circuit 2c Electronic integrated circuit 3a, 3b Light emitting element 4a, 4b Light receiving element 5a, 5b, 5c Electronic circuit 6a, 6b Waveguide 7 Electric wiring 8a, 8b, 8c, 8d Optical transmission end 9 Wire 10 Mold 10a Material injection port 11 Void 12 Optical transmission path support base 20 Mold 20a Material injection port 21 Vacancy 22, 22a, 22b, 22c, 22d Optical transmission path 23 Signal light 30 Optical transmission circuit 100 Support base 101 Substrate mounting table 102a, 102b Guide 103, 109 Slider 104 Ball screw 105, 107, 110 Servo motor 106 X direction drive unit 108 Y direction drive unit 111 Z direction drive unit 112 Support column 113 Camera 114a, 114b Syringe 115a, 105b Material transfer unit 116 Control part 118 Mold mounting part

Claims (2)

In an optical transmission path forming method of forming an optical transmission path between optical transmission ends of an optical transmission path forming body having an optical transmission end connected by an optical transmission path and performing optical transmission via the optical transmission path ,
A void having the same shape as the optical transmission path support for supporting the optical transmission path is formed between the optical transmission path formation body and the optical transmission path formation body. A first step of forming the optical transmission line support base by placing a mold and injecting a solidifying optical transmission path support base forming material in a fluid state into the void;
On the optical transmission path support base, a second mold is formed in which a cavity having the same shape as the optical transmission path is formed between the optical transmission path support base and the cavity. And a second step of forming the optical transmission path by injecting a solidifying optical transmission path forming material in a fluid state.   The optical transmission path is formed by using a mold that forms an optical transmission path including a branching portion that branches an optical transmission path extending from one optical transmission end toward a plurality of optical transmission ends as the second mold. The method of forming an optical transmission line according to claim 1.

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