JP2004031456A - Optical interconnection device and interconnection module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical interconnection device which can be miniaturized still more, can easily cope with a change of a circuit and can reduce production costs; and an interconnection module structuring the optical interconnection device. <P>SOLUTION: For example, a surface-emitting semiconductor laser 21 and a driver IC 22 are three-dimensionally disposed across a sub-mount substrate 20a, and an LSI 23 such as a CPU or the like is mounted on the driver IC 22. Through holes are provided in all of the sub-mount substrate 20a, the surface-emitting semiconductor laser 21, the driver IC 22 and the LSI 23, and these parts are electrically connected through conductors in the through holes. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical interconnection device mounted inside a computer such as a server and a client and a device such as a router and used as an interface between an LSI such as a CPU and a memory and an opto-electric hybrid board, and the optical interconnection device thereof Related to the interconnection module.
[0002]
[Prior art]
With the development of information and communication technology and information processing technology, the density of electric wiring connecting electronic circuits in devices such as computers and large-capacity exchanges has been increasing, which has become a factor that hinders the increase in scale and performance of systems. Was. In addition, the remarkable development of LSI in recent years has resulted in a higher density of input / output terminals of the LSI and a higher density of electric wiring inside the LSI, which has become a bottleneck for performance improvement. In order to solve such a problem, attention has been paid to an optical interconnection technology for connecting electronic circuits with light.
[0003]
An optical interconnection device generally drives a light emitting element such as a surface emitting semiconductor laser (VCSEL: Vertical Cavity Surface Emitting Laser), a driver IC for driving the light emitting element, a light receiving element such as a photodiode, and the light receiving element. Components such as a receiver IC (hereinafter referred to as an interconnection module) are two-dimensionally arranged on a submount substrate. In many cases, an LSI on which a CPU circuit or a memory circuit is formed together with these interconnection modules is mounted on a submount substrate.
[0004]
[Problems to be solved by the invention]
However, the conventional optical interconnection device has a drawback that since each interconnection module is two-dimensionally arranged, the mounting area is large, and miniaturization is difficult. In addition, since the wiring length of the electric wiring connecting between the interconnection modules becomes long, there is a problem that high-speed operation is hindered and the S / N ratio is deteriorated due to crosstalk noise.
[0005]
An optical interconnection device in which a silicon substrate is used as a submount substrate, a driver circuit, a receiver circuit, a CPU circuit, and the like are formed on the silicon substrate, and a light emitting element and a light receiving element are mounted on the silicon substrate has been developed. However, in this type of optical interconnection device, since the driver circuit, the receiver circuit, the CPU circuit, and the like are monolithically integrated, it is difficult to change the circuit, and the versatility is low.
[0006]
In order to reduce the size of the optical interconnection device, it is conceivable to arrange each interconnection module three-dimensionally (3D). For example, an optical element (light emitting element or light receiving element) is mounted under the submount substrate, and a driver IC or a receiver IC is mounted on the submount substrate. However, when the interconnection modules are three-dimensionally arranged, it becomes impossible to electrically connect the interconnection modules.
[0007]
Also, for example, in a surface emitting semiconductor laser, electrodes are provided on a light emitting side and a surface opposite to the light emitting side, so that the electrode on one side can be directly connected to the submount substrate, while the electrode on the other side is a wire. It is necessary to connect to the submount substrate by a method such as bonding. For this reason, there is also a problem that the mounting process is complicated.
[0008]
Further, in the conventional optical interconnection device, since a relatively expensive substrate such as a ceramic substrate or a silicon PLC (Planar Lightwave Circuit) substrate is used as a submount substrate, there is a disadvantage that the product cost is increased.
[0009]
In view of the above, it is an object of the present invention to provide an optical interconnection device which can be further miniaturized, can easily cope with circuit changes, and can reduce product cost, and an optical interconnection device thereof. It is intended to provide an interconnection module.
[0010]
[Means for Solving the Problems]
An optical interconnection device of the present invention includes a main substrate, a submount substrate disposed above the main substrate, a support member for supporting the submount substrate, and an optical element mounted with the submount substrate interposed therebetween. A module and an optical element driving module, wherein the sub-mount substrate, the optical element module and the optical element driving module each have a through hole penetrating from one surface to the other surface, and the sub-mount substrate , The optical element module and the optical element drive module are electrically connected via a conductor in the through hole.
[0011]
The optical element module and the optical element drive module may be stacked and mounted on one surface side of a submount substrate. Further, the optical element module and the optical element drive module may be directly mounted on the main substrate without using the submount substrate.
[0012]
In the present invention, an optical element module such as a surface emitting semiconductor laser and a photodiode and an optical element driving module such as a driver IC or a receiver IC for driving the optical element are three-dimensionally arranged. Both the optical element module and the optical element drive module are provided with through holes, and the optical element module and the optical element drive module are electrically connected via the conductor in the through hole. These modules can be arranged three-dimensionally. Thereby, the size of the optical interconnection device can be reduced. Further, since the modules are electrically connected to each other via the conductor in the through-hole, the wiring length is short and the characteristics such as the S / N ratio are good.
[0013]
Further, by modularizing each function, it is possible to easily cope with circuit changes. Further, a normal printed wiring board or a flexible board can be used as the sub-mount board, and a ceramic board, a silicon PLC board, and the like are not required, so that the product cost can be reduced as compared with the related art.
[0014]
Further, the interconnection module of the present invention includes a first electrode provided on the first surface, a second electrode provided on the second surface, and a second electrode provided on the second surface. It has a through hole penetrating therethrough, and a conductor formed in the through hole and electrically connecting the first electrode and the second electrode.
[0015]
In the present invention, the interconnection module is provided with a through hole, and the second electrode on the first surface side and the second electrode on the second surface side are electrically connected to each other through the conductor in the through hole. Connected. Therefore, when the interconnection modules are stacked, each module is electrically connected via the conductor in the through hole. That is, in the interconnection module of the present invention, the respective modules are stacked and arranged, and power is supplied through the conductors in the through holes of the respective modules, and signals are input / output. This makes it possible to configure an optical interconnection device by combining desired modules, so that the versatility is high. Further, the wiring length between the modules can be reduced, and the S / N ratio is improved.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0017]
(First Embodiment)
FIG. 1 is a schematic diagram showing an example of the optical connection device according to the first embodiment of the present invention.
[0018]
On the opto-electric hybrid board (main board) 10, an optical waveguide 11 and electric wiring (not shown) are formed in a predetermined pattern. In the present embodiment, a substrate in which a sheet-shaped optical waveguide made of a polymer material is attached to a printed wiring board is used as the opto-electric hybrid board 10. However, in the present invention, the structure of the main board is not limited to this.
[0019]
A mirror 11 a is provided at a predetermined position of the optical waveguide 11, and guides light emitted from a surface emitting semiconductor laser 21 described later to the optical waveguide 11, and transmits light passing through the optical waveguide 11 to a photodiode 24 described later. It is designed to reflect toward.
[0020]
Support members 15a and 15b are arranged on the opto-electric hybrid board 10, and the submount substrates 20a and 20b are supported by the support members 15a and 15b and arranged above the opto-electric hybrid board 10. In the present embodiment, the submount substrates 20a and 20b are rigid substrates formed of, for example, an organic polymer. Electric wiring (pattern wiring) is formed on these sub-mount substrates 20a and 20b, and these wirings are connected to the electric wiring of the opto-electric hybrid board 10 via the flexible substrates 12a and 12b.
[0021]
A surface emitting semiconductor laser 21 is mounted under the submount substrate 20a. Light emitted from the surface emitting semiconductor laser 21 is reflected by the mirror 11 a and guided into the optical waveguide 11.
[0022]
A driver IC 22 on which a circuit for driving the surface emitting semiconductor laser 21 is formed is mounted on the submount substrate 20a, and an LSI 23 on which a circuit such as a CPU or a memory is formed is mounted on the driver IC 22. Have been.
[0023]
These submount substrate 20a, surface emitting semiconductor laser 21, driver IC 22, and LSI 23 are all provided with electrodes on the upper and lower surfaces. The submount substrate 20a, the surface emitting semiconductor laser 21, the driver IC 22, and the LSI 23 are provided with through holes (shown by broken lines in FIG. 1) penetrating from the upper surface to the lower surface. The electrode is electrically connected to a predetermined one of the electrodes on the other surface via a conductor in the through hole. The electrodes of the submount substrate 20a and the electrodes of the surface emitting semiconductor laser 21 and the driver IC 22, and the electrodes of the driver IC 22 and the LSI 23 are connected to each other by solder bumps (not shown).
[0024]
That is, in the present embodiment, the electrical connection between the surface emitting semiconductor laser 21, the driver IC 22, and the LSI 23, and between these components and the submount substrate 20a are provided on each component and the submount substrate 20a. Through the conductor in the through hole.
[0025]
The electric wiring of the sub-mount substrate 20a is connected to the electric wiring of the opto-electric hybrid board 10 via the flexible substrate 12a, and the electric power to the surface emitting semiconductor laser 21, the driver IC 22, and the LSI 23 via these electric wirings. Supply and input / output of electric signals.
[0026]
Similarly, a photodiode 24 is mounted below the submount substrate 20b, and a receiver IC 25 having a circuit for driving the photodiode 24 is mounted above the submount substrate 20b. On the receiver IC 25, an LSI 26 in which a circuit such as a CPU or a memory is formed is mounted.
[0027]
The submount substrate 20b, the photodiode 24, the receiver IC 25, and the LSI 26 are all provided with electrodes on the upper and lower surfaces. The sub-mount substrate 20b, the photodiode 24, the receiver IC 25, and the LSI 26 are provided with through-holes penetrating from the upper surface to the lower surface, and the electrode on one surface side is provided through a conductor in the through-hole. It is electrically connected to a predetermined electrode on the other surface. The electrodes of the submount substrate 20b and the electrodes of the photodiode 24 and the receiver IC 25, and the electrodes of the receiver IC 25 and the LSI 26 are connected to each other by solder bumps (not shown).
[0028]
Further, the electric wiring of the submount substrate 20b is connected to the electric wiring of the opto-electric hybrid board 10 via the flexible substrate 12b, and power is supplied to the photodiode 24, the receiver IC 25, and the LSI 26 through these electric wirings. And input and output of electrical signals.
[0029]
FIG. 2 is a schematic sectional view of the surface emitting semiconductor laser 21. In the surface-emitting semiconductor laser 21, an anode electrode 31 is provided on a surface on the light emission side, and a cathode electrode 32 is provided on the back surface side. In the present embodiment, the anode electrode 31 provided on the light emission side surface is electrically connected to the back surface side electrode 33 via the extraction electrode 36 and the conductor film 35 in the through hole 30. .
[0030]
The through holes 30 are formed by, for example, a reactive ion etching (RIE) method. Thereafter, an insulating film 34 such as SiO ₂ or SiN is formed on the wall surface in the through hole 30 by sputtering or CVD, and Pt (platinum) or Pt (platinum) is formed on the insulating film 34 by sputtering or CVD. A conductor film 35 such as Au (gold) is formed. Then, an electrode 33 electrically connected to the conductor film 35 in the through hole 30 is formed on the same surface side as the cathode electrode 32, and the anode electrode 31 and the conductor film 35 are electrically connected to the surface on the anode electrode 31 side. An extraction electrode 36 is formed to be electrically connected.
[0031]
FIG. 3 is a schematic sectional view of the photodiode 24. In the photodiode 24, an anode electrode 41 and a cathode electrode 42 are provided on the light receiving surface side. These electrodes 41 and 42 are electrically connected to the electrodes 45 and 46 on the back side via the conductor film 44 in the through hole 40. Note that an insulating film 43 is formed between the wall surface of the through hole 40 and the conductor film 44.
[0032]
FIG. 4 is a schematic sectional view of the driver IC 22. The driver IC 22 also has a through hole 50 penetrating from one surface to the other surface. The through holes 50 are formed by, for example, reactive ion etching. Then, after an insulating film 51 and a conductor film 52 covering the inner wall surface of the through hole 50 are sequentially formed, an electrode 53 is formed on one surface side, and an electrode 55 is formed on the other surface side. Although only one through-hole is shown in FIG. 4 in the driver IC 22, actually, as many through-holes as necessary for power supply and signal transmission are provided.
[0033]
The receiver IC 25 and the LSIs 23 and 26 also have a plurality of through holes as in the driver IC 22. Although the insides of the through holes 30, 40, and 50 are hollow in FIGS. 2 to 4, a conductor may be embedded in the through holes after forming an insulating film on the inner wall surface of the through holes.
[0034]
In the present embodiment, the surface emitting semiconductor laser 21, the submount substrates 20a and 20b, the driver IC 22, the photodiode 24, the receiver IC 25, and the LSIs 23 and 26 which constitute the optical interconnection device all have through holes. Since the components are electrically connected via the conductor in the through-hole, the components can be three-dimensionally arranged and driven. As a result, the optical interconnection device can be more highly integrated than in the past.
[0035]
Further, in the present embodiment, the step of connecting the interconnection module and the sub-mount substrates 20a and 20b by wire bonding or the like is unnecessary, and the assembly is easy.
[0036]
Further, in the present embodiment, since the length of the wiring connecting the modules is reduced, high-speed operation is enabled, and characteristics such as S / N ratio are improved. Furthermore, in the present embodiment, since each function is an individual module, it is possible to easily cope with a change in the circuit and to improve the reliability of the product.
[0037]
In the present embodiment, the case where the submount substrates 20a and 20b are electrically connected to the opto-electric hybrid board 10 via the flexible substrates 12a and 12b has been described, but the present invention is not limited to this. For example, the support members 15a and 15b may be provided with leads for electrically connecting the submount substrates 20a and 20b and the opto-electric hybrid board 10.
[0038]
Alternatively, power may be supplied to the driver IC 22, the receiver IC 25, and the LSIs 23 and 26 via leads provided on the support members 15a and 15b, and signals may be input and output via a flexible substrate.
[0039]
Further, in the present embodiment, a case has been described in which the submount substrates 20a and 20b are rigid substrates formed of an organic polymer. However, as shown in FIG. 5, as a submount substrate, a flexible substrate 27a provided with through holes is provided. , 27b may be used. In this case, it is possible to directly connect the electric wiring of the submount substrate and the electric wiring of the opto-electric hybrid board 10. Thus, the structure is further simplified, and further cost reduction can be realized.
[0040]
Furthermore, in the above embodiment, the case where the surface emitting semiconductor laser 21 and the driver IC 22 are arranged with the sub-mount substrate 20a interposed therebetween, and the photodiode 24 and the receiver IC 25 are arranged with the sub-mount substrate 20b interposed therebetween will be described. However, as shown in FIG. 6, the surface emitting semiconductor laser 21 and the driver IC 22, and the photodiode 24 and the receiver IC 25 may be arranged on one surface side of the submount substrates 20a and 20b. In the case of the optical interconnection device shown in FIG. 6, an LSI (not shown) such as a CPU and a memory is mounted on the opto-electric hybrid board 10, and the driver IC 22 and the receiver are connected via the flexible boards 12a and 12b. It is electrically connected to the IC 25.
[0041]
(Second embodiment)
FIG. 7 is a schematic diagram showing an optical interconnection device according to a second embodiment of the present invention, and FIG. 8 is an enlarged view of a portion indicated by a circle in FIG.
[0042]
On the opto-electric hybrid board 60, an optical waveguide 61 and electric wiring (not shown) are respectively formed in a predetermined pattern. A mirror 61a is provided at a predetermined position of the optical waveguide 61, and guides light emitted from the surface emitting semiconductor laser 71 to the optical waveguide 61, and directs light passing through the optical waveguide 61 to a photodiode 73 described later. It is designed to reflect.
[0043]
In the present embodiment, the surface emitting semiconductor laser 71 and the photodiode 73 are directly mounted on the opto-electric hybrid board 60. That is, as shown in FIG. 8, the photoelectric hybrid substrate 60 is provided with an electrode 60a for connecting the surface emitting semiconductor laser 71 and the photodiode 73, and is provided on the surface emitting semiconductor laser 71 and the photodiode 73. The electrodes 70a are joined by the solder bumps 63. When there is a step on the light emitting side surface of the surface emitting semiconductor laser 71, it is preferable to eliminate the step by using polyimide or the like.
[0044]
A driver IC 72 is mounted on the surface emitting semiconductor laser 71, and a receiver IC 74 is mounted on the photodiode 73. These surface emitting semiconductor laser 71, driver IC 72, photodiode 73, and receiver IC 74 are all provided with through holes (shown by broken lines in FIG. 7). The electrical wiring of the opto-electric hybrid board 60 and the electrodes of the surface emitting semiconductor laser 71, the driver IC 72, the photodiode 73, and the receiver IC 74 are electrically connected via the conductors in these through holes.
[0045]
In this embodiment, LSIs (not shown) such as a CPU and a memory are mounted on the opto-electric hybrid board 60, and the electric wiring of the opto-electric hybrid board 60 and the penetration of the surface emitting semiconductor laser 71 and the photodiode 73 are provided. It is connected to the driver IC 72 and the receiver IC 74 via the hole.
[0046]
In the present embodiment, each optical connection module is three-dimensionally arranged on the opto-electric hybrid board 60 without using a sub-mount board. The alignment between the surface emitting semiconductor laser 71 and the photodiode 73 is performed in a self-aligned manner, and the number of alignment steps can be reduced. That is, as shown in FIG. 9, when the electrode 60 a of the opto-electric hybrid board 60 and the electrode 70 a of the surface emitting semiconductor laser 71 (or the photodiode 73) are joined by the solder bump 63, On the other hand, even if the position of the surface emitting semiconductor laser 71 (or the photodiode 73) is slightly shifted, the position of the surface emitting semiconductor laser 71 (or the photodiode 73) is automatically set to a predetermined position due to the surface tension of the solder bump 63. Will be modified. Thus, the step of adjusting the alignment between the surface emitting semiconductor laser 71 and the photodiode 73 and the optical waveguide becomes unnecessary, and the manufacturing cost is reduced.
[0047]
Further, in this embodiment, since a submount substrate and a flexible substrate are not required, the cost can be further reduced as compared with the first embodiment.
[0048]
In this embodiment, an LSI such as a CPU or a memory is mounted on the opto-electric hybrid board 60, and the wiring on the opto-electric hybrid board 60 and the through holes of the surface emitting semiconductor laser 71 and the photodiode 73 are provided. In the same manner as in the first embodiment, an LSI in which a circuit such as a CPU or a memory is formed on a surface emitting semiconductor laser 71 and a receiver IC 74 is mounted. It may be.
[0049]
【The invention's effect】
As described above, according to the optical interconnection device of the present invention, the through-holes are provided in the optical element module and the optical element drive module, and the modules are connected to each other via the conductor in the through-hole. Therefore, the optical element module and the optical element drive module can be mounted three-dimensionally on the main board or the sub-mount board. This makes it possible to reduce the size of the optical interconnection device as compared with the conventional one, and to easily cope with circuit changes. Further, since a normal printed wiring board can be used as the submount board, the product cost can be reduced.
[0050]
Further, in the interconnection module of the present invention, the first electrode provided on the first surface and the second electrode provided on the second surface are electrically connected to each other via a conductor in the through hole. Therefore, a plurality of modules can be stacked three-dimensionally to electrically connect the modules. Thus, it is possible to easily cope with a change in the circuit and to reduce the mounting area.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of an optical connection device according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of the surface emitting semiconductor laser used in the first embodiment.
FIG. 3 is a schematic cross-sectional view of the photodiode used in the first embodiment.
FIG. 4 is a schematic sectional view of a driver IC used in the first embodiment.
FIG. 5 is a schematic diagram showing a modification of the first embodiment, and shows an example in which a flexible substrate provided with through holes is used as a submount substrate.
FIG. 6 is a schematic view showing another modified example of the first embodiment, and shows an example in which two interconnection modules are stacked and mounted on one surface side of a submount substrate.
FIG. 7 is a schematic diagram showing an optical interconnection device according to a second embodiment of the present invention.
FIG. 8 is an enlarged view of a portion indicated by a circle in FIG. 7;
FIG. 9 is a schematic diagram showing how the position of a surface emitting semiconductor laser is automatically adjusted by the surface tension of a solder bump.
[Explanation of symbols]
10, 60 ... photoelectric hybrid board,
11, 61 ... optical waveguide,
11a, 61a ... mirror,
12a, 12b, 27a, 27b ... flexible substrate,
15a, 15b ... support members,
20a, 20b ... submount substrate,
21, 71 ... surface emitting semiconductor laser (VCSEL),
22, 72 ... Driver IC,
23, 26 ... LSI,
24, 73 ... photodiode,
25, 74 ... receiver IC,
30, 40, 50 ... through-hole,
31, 32, 33, 35, 41, 42, 45, 46, 53, 54, 60a, 70a ... electrodes,
34, 43, 51 ... insulating film,
35, 44, 52 ... conductive film,
63: Solder bump.

Claims (6)

A main board,
A sub-mount substrate disposed above the main substrate,
A support member for supporting the submount substrate,
Having an optical element module and an optical element drive module mounted with the sub-mount substrate in between,
The submount substrate, the optical element module, and the optical element drive module each have a through hole penetrating from one surface to the other surface, and the wiring of the submount substrate, the optical element module, and the optical element The optical interconnection device, wherein the drive module is electrically connected through a conductor in the through hole. A main board,
A sub-mount substrate disposed above the main substrate,
A support member for supporting the submount substrate,
Having an optical element module and an optical element driving module stacked and mounted on one surface side of the submount substrate,
Each of the optical element module and the optical element drive module has a through-hole penetrating from one surface to the other surface, and the wiring of the submount substrate, the optical element module and the optical element drive module, An optical interconnection device electrically connected through a conductor in a through hole. The optical interconnection device according to claim 1, wherein the electric wiring of the sub-mount substrate and the electric wiring of the main substrate are connected via a flexible substrate. The optical interconnection device according to claim 1, wherein the submount substrate is made of a flexible substrate. A main board,
Having an optical element module and an optical element drive module stacked and mounted on the main substrate,
Each of the optical element module and the optical element driving module includes a first electrode provided on a first surface, a second electrode provided on a second surface, and a second electrode provided on the first surface. And a conductor formed in the through-hole and electrically connecting the first electrode and the second electrode, and a solder bump is provided between each module. An optical interconnection device characterized by being joined. In an interconnection module constituting an optical interconnection device for connecting electronic circuits with light,
A first electrode provided on the first surface;
A second electrode provided on the second surface;
A through hole penetrating from the first surface to the second surface;
An interconnection module comprising: a conductor formed in the through hole to electrically connect the first electrode and the second electrode.

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