JP2015068846A - Optical waveguide type module and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide type module capable of corresponding to higher speed with an inexpensive structure.SOLUTION: An optical waveguide type module includes: an optical waveguide substrate 1 on which an optical waveguide is formed; a photoelectric element 2 for optically connecting the optical waveguide to transmit/receive an optical signal; an interposer substrate 4; and an element 6 for signal amplification. The interposer substrate 4 includes a surface side electrode, a side surface side electrode, and connection wiring for connecting them. The surface side electrode is electrically connected with the photoelectric element 2. The element 6 for signal amplification is electrically connected with the side surface side electrode via a joint material 7.

Description

  The present invention relates to an optical waveguide module and a method for manufacturing the same, and more particularly to an optical waveguide module that performs photoelectric signal conversion using a semiconductor element for optical communication and an optical waveguide substrate, and a method for manufacturing the same.

  With the recent development of high-speed technology for devices such as LSI, the speed limit of electrical communication methods has become a problem. For this reason, development and research of optical communication, optical information processing, and the like are underway as an alternative to electrical communication methods. The optical waveguide module is a module including an optical waveguide that is a transmission path for optical communication. It is a component that has the function of receiving optical signals or electrical signals, converting them to each other, and outputting them.

Patent Document 1 shows an example of such an optical waveguide type module.
The optical waveguide module described in Patent Document 1 is an optical waveguide module having an optical waveguide substrate on which an optical waveguide is formed and a light receiving element. One end portion of the optical waveguide substrate is a plane in a direction intersecting with the optical waveguide, and is a filter joint surface in which the end face of the core of the optical waveguide is exposed, and a plane parallel to the filter joint surface. And a wiring board bonding surface at a position protruding outward from the surface. A filter is bonded to the filter bonding surface, and a part of the wiring substrate is bonded to the wiring substrate bonding surface. The light receiving element is mounted on the wiring board such that the surface on which the light receiving region of the light receiving element is formed faces the surface of the wiring board on the filter joint surface side. The wiring substrate is positioned and fixed with respect to the optical waveguide substrate so that the surface opposite to the surface on which the light receiving region of the light receiving element is formed faces the end surface of the core of the optical waveguide.

  On the other hand, in the optical waveguide module, it is preferable to reduce the capacitance existing in the electrical wiring in order to increase the communication speed. For this purpose, the wiring length is preferably as short as possible. The area of the light receiving / emitting region of the optical element is preferably as small as possible.

In addition, quartz (SiO ₂ ) is the mainstream material for the optical waveguide substrate used in the optical waveguide module, but in recent years, development of optical waveguides using silicon (Si) has been progressing. Since silicon (Si) is less expensive than quartz (SiO ₂ ), it is suitable for reducing the manufacturing cost of the optical waveguide. Silicon (Si) has a higher refractive index than quartz (SiO ₂ ) and is suitable for miniaturization of the optical waveguide. However, since the refractive index of silicon (Si) is higher than that of quartz (SiO ₂ ), the radiation angle of light from the end face of the optical waveguide made of silicon is about twice that of the optical waveguide made of quartz (full angle). About 80 degrees).

JP 2008-170868 A

  In the optical waveguide module described in Patent Document 1 described above, the electrical wiring connecting the optical element and the signal amplification element requires a length of about several millimeters. For this reason, there is a problem that an electric signal is deteriorated due to an electrostatic capacity or the like existing in the electric wiring, and high-speed communication of 25 Gbps or more cannot be supported.

In addition, when a silicon optical waveguide is employed for miniaturization and cost reduction, the radiation angle of light from the end face of the optical waveguide by silicon (Si) is due to quartz (SiO ₂ ) due to the difference from the refractive index of air. As compared with the optical waveguide, it spreads about twice (full angle about 80 degrees). Therefore, there is a problem that the optical coupling efficiency is lowered and the sensitivity of the light receiving element is deteriorated.

  As described above, the related optical waveguide type module has a problem that it is difficult to cope with higher speed with a low-cost structure.

  An object of the present invention is to provide an optical waveguide type module that solves the above-mentioned problem that it is difficult to cope with higher speed with a low-cost structure.

  An optical waveguide module of the present invention includes an optical waveguide substrate on which an optical waveguide is formed, a photoelectric element that is optically connected to the optical waveguide and transmits and receives an optical signal, an interposer substrate, and a signal amplification element. The interposer substrate includes a surface side electrode, a side surface electrode, and a connection wiring that connects the surface side electrode and the side surface type electrode. The surface side electrode is electrically connected to the photoelectric element, and the signal amplification element is The electrode is electrically connected to the side electrode through a bonding material.

  In the method of manufacturing an optical waveguide module according to the present invention, the photoelectric element is fixed to the surface of the interposer substrate, external wiring is formed through which the side electrode and back electrode of the interposer substrate are connected through the outside, and the photoelectric device is connected via the external wiring. Power is supplied to the element, the operating characteristics of the photoelectric element are measured, the position of the photoelectric element relative to the optical waveguide substrate is adjusted, the optimum position where the operating characteristics are the best is determined, and the photoelectric element is fixed at the optimum position.

  According to the optical waveguide module and the method of manufacturing the same of the present invention, it is possible to cope with further increase in speed with a low-cost structure.

It is a figure which shows the structure of the optical waveguide type module which concerns on the 1st Embodiment of this invention, and is sectional drawing cut | disconnected by the surface which passes along the center of an optical waveguide. It is sectional drawing for demonstrating the manufacturing method of the optical waveguide type module which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the optical waveguide type module which concerns on the 1st Embodiment of this invention. It is a side view which shows the structure of the optical waveguide type module which concerns on embodiment of this invention, and is the figure seen from the back surface side of the interposer board | substrate. It is sectional drawing which shows the structure of the optical waveguide type module which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the optical waveguide type module which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the optical waveguide type module which concerns on the 4th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
In the present embodiment, an external wiring for electrically connecting the surface side electrode and the side surface electrode is provided on the interposer substrate, and a photoelectric element of a type that inputs and outputs light from the back surface is mounted on the surface side of the interposer substrate. The side electrode and the signal amplification element are electrically connected. As a result, the length of the electric wiring connecting the photoelectric element through which a high-speed signal such as 25 Gbps passes and the signal amplification element is shortened.

In addition, a removable conductive wire is provided in a part of the external wiring of the interposer substrate, and when the conductive wire is connected, the photoelectric element is supplied from the outside using an energization probe or the like. This
Active alignment becomes possible. That is, by introducing light into the optical waveguide of the optical waveguide substrate while electrically operating the photoelectric element, the positional relationship between the optical waveguide and the photoelectric element is the highest in operating characteristics while measuring the operating characteristics as an optical module. Adjustments can be made to the position. For example, it becomes easy to apply a high-speed photoelectric element having a small light receiving / emitting region (functional part) of φ20 μm to an optical module product.

  Further, after the photoelectric element is positioned and fixed with respect to the optical waveguide substrate, the conductive wire for supplying power to the photoelectric element from the outside is removed. As a result, after mounting, the electrical wiring through which high-speed signals pass becomes connection wiring that connects the front and side surfaces of the interposer board, and the length can be shortened to the minimum necessary, and the capacitance existing in the electrical wiring can be reduced. Can be reduced.

  In addition, by fixing a photoelectric element having a convex lens on the surface facing the optical waveguide substrate of the photoelectric element to the side surface of the optical waveguide substrate, light emitted from a wide angle of about 80 degrees from the end surface of the optical waveguide can be obtained. It is possible to collect light efficiently.

  FIG. 1 is a diagram showing a configuration of an optical waveguide module according to the first embodiment of the present invention, and is a cross-sectional view cut along a plane passing through the center of the optical waveguide.

  The optical waveguide module of the present embodiment includes an optical waveguide substrate 1 on which an optical waveguide 8 is formed, a photoelectric element 2 that is optically connected to the optical waveguide 8 and transmits and receives an optical signal, an interposer substrate 4, a signal And an amplifying element 6. The interposer substrate 4 includes a surface side electrode, a side surface electrode, and a connection wiring that connects the surface side electrode and the side surface electrode. The surface side electrode is electrically connected to the photoelectric element 2. The signal amplification element 6 is electrically connected to the side electrode via the bonding material 7.

The optical waveguide substrate 1 is an optical waveguide substrate in which an optical waveguide 8 is formed by performing a semiconductor process on the surface of a silicon (Si) substrate. The optical waveguide 8 can be an optical waveguide that transmits laser light having an infrared wavelength used in optical communication. As a material for the optical waveguide 8, for example, quartz (SiO ₂ ) or an organic material can be used in addition to silicon (Si).

  The photoelectric element 2 is an optical semiconductor element that emits or receives light. Examples of the material of the photoelectric element 2 include compound semiconductors such as InP and GaAs. A functional unit that emits or receives light is provided on the surface side of the photoelectric element 2. In addition, a curved surface serving as a lens for improving the coupling efficiency between the photoelectric element 2 and the optical waveguide 8 is formed on the back surface side that is the incident / exit side of the photoelectric element 2. When the photoelectric element 2 is a light receiving element, the lens condenses the light emitted from the end face of the optical waveguide 8 on the functional part. When the photoelectric element 2 is a light emitting element, the lens outputs light output from the photoelectric element 8. Condensed on the end face of

  The back surface side of the photoelectric element 2 is fixed to the end surface of the optical waveguide substrate 1 through the bonding material 3. The bonding material 3 is an adhesive such as an epoxy resin. The photoelectric element 2 is mounted on the interposer substrate 4.

  The interposer substrate 4 is a wiring substrate made of, for example, ceramic or organic material. In the interposer substrate 4, connection wiring for connecting the surface side electrode and the side surface side electrode is formed.

The side electrode of the interposer substrate 4 and the signal amplification element 6 are electrically connected via a bonding material 7. The bonding material 7 is a conductive adhesive such as silver paste. In addition, on the back surface outside the interposer substrate 4, conductive wires 5 are provided as external wirings that electrically connect the side surface electrodes and the back surface side electrodes. The conductive wire 5 is, for example, a wire made of gold (gold wire, gold ribbon) or the like used for wire bonding, a wiring pattern that can be divided or removed by a subsequent process such as laser processing, or the like. The conductive wire 5 has a portion that can be cut at least in the vicinity of the side electrode. The optical waveguide substrate 1 and the signal amplification element 6 are each fixed on the base 9.

  Next, a method for manufacturing the optical waveguide module according to this embodiment will be described.

  In the method of manufacturing an optical waveguide module according to this embodiment, first, the photoelectric element 2 is mounted on the surface of the interposer substrate 4. Conductive lines 5 for feeding power to the interposer substrate 4 are formed, and the operational characteristics of the photoelectric elements 2 are measured while feeding the photoelectric elements 2 via the conductive lines 5. At this time, while adjusting the position of the photoelectric element 2 with respect to the optical waveguide substrate 1, the optimum position that provides the best operating characteristics is determined, and the photoelectric element 2 is fixed at the optimum position.

  The method for manufacturing the optical waveguide module according to the present embodiment will be described in more detail with reference to FIG.

  First, the photoelectric element 2 is mounted on the surface of the interposer substrate 4 (step S1). As a mounting material, for example, gold-tin solder is available. The mounting material has a high melting point so as not to be remelted by heating at the time of assembly in a subsequent process and to lose the electrical connection or shift the fixing position.

  Next, the conductive wire 5 is formed on the interposer substrate 4 (step S2). The conductive line 5 is an external wiring for supplying power to the photoelectric element 2 necessary in a later process.

  Next, the photoelectric element 2 mounted on the interposer substrate 4 is temporarily fixed to the optical waveguide substrate 1 through the bonding material 3 (step S3). This is done by applying pressure with a light load, for example 10 grams weight (gf).

  Next, position adjustment in the in-plane direction of the bonding surface between the optical waveguide substrate 1 and the photoelectric element 2 is performed (step S4). An active alignment method is used for this position adjustment. That is, power is supplied to the photoelectric element 2 through the conductive wire 5 and the operational characteristics of the photoelectric element 2 are measured. At this time, while adjusting the position of the photoelectric element 2 with respect to the optical waveguide substrate 1, the optimum position with the best operating characteristics is determined, and the photoelectric element 2 is fixed at the optimum position. The operating characteristics here are the intensity of light emitted from the back surface type optical element 2 and passing through the optical waveguide 8 when the photoelectric element 2 is a light emitting element, and the optical waveguide when the photoelectric element 2 is a light receiving element. 8 is the intensity of light incident on the photoelectric element 2 through 8.

  FIG. 2 is a cross-sectional view for explaining the manufacturing method according to the first embodiment of the present invention. In order to supply power to the photoelectric element 2, for example, a tool such as an energization probe 14 is brought into contact with the surface side electrode of the interposer substrate 4. The connection wiring of the interposer substrate 4 is energized through the energization probe 14 and the conductive wire 5 to supply power to the photoelectric element 2. Thereby, when the photoelectric element 2 is a light receiving element, a light receiving function can be realized, or when the photoelectric element 2 is a light emitting element, a light emitting function can be realized.

  Next, the bonding material 3 is cured to fix the optical waveguide substrate 1 and the photoelectric element 2 (step S5). The curing means may be appropriately changed according to the properties of the bonding material. For example, when the bonding material 3 is a type of adhesive that is cured by heating, the heating may be performed by a heater or the like. Alternatively, when the bonding material 3 is an adhesive that is cured by light irradiation, the bonding material 3 may be irradiated with light.

  Next, the conductive wire 5 provided on the back surface of the interposer substrate 4 is divided and removed (removed) (step S6). At this time, the conductive wire 5 is cut off at least in the vicinity of the side electrode. For example, when the conductive wire 5 is an electric wire, it may be removed by cutting both ends. Or when the conductive wire 5 is a wiring pattern, it can be excised by laser processing or the like.

  By dividing / removing the conductive wire 5, it is possible to remove the capacitance that is parasitic on the external wiring. Here, the connection between the photoelectric element 2 and the signal amplification element 6 is the shortest connection wiring from the front surface side electrode to the side surface side electrode of the interposer substrate 4. Therefore, the operational characteristics of the photoelectric element 2 and the signal amplification element 6 can be improved.

  Next, the signal amplification element 6 is mounted on the base 9 (step S7). The mounting material may be a conductive adhesive that is cured by heat, such as silver paste. The signal amplifying element 6 is arranged such that its connection terminal is on the top.

  Next, the optical waveguide substrate 1 is mounted on the base 9 (step S8). At that time, the position adjustment is performed so that the side electrode of the interposer substrate 4 is electrically connected to the predetermined electrode of the signal amplification element 6 through the bonding material 7.

  Finally, the mounting material on which the optical waveguide substrate 1 and the signal amplifying element 6 are mounted and the bonding material 7 are simultaneously cured and fixed using a heating tool such as a heater (step S9).

  FIG. 4 is a view of an example of the optical waveguide module according to the present embodiment as viewed from the back side of the interposer substrate. Here, as an example, a case where four functional units 15 are arranged in a line in the photoelectric element 2 is shown.

  In the example of FIG. 4, a step of adjusting the position in the in-plane direction of the bonding surface between the optical waveguide substrate 1 and the photoelectric element 2 (step S <b> 4) is shown. Here, the energization probe is brought into contact with two energization probe electrodes (for Signal) 16 and one energization probe electrode (for GND) 17 exposed on the surface side of the interposer substrate 4 to supply power. With such a configuration, the functional unit 15 that performs light emission or light reception at two locations on both ends of the photoelectric element 2 can be operated.

  In the example shown in FIG. 4, the distance between the four optical waveguides 8 of the optical waveguide substrate 1 and the four functional portions 15 of the photoelectric element 2 is formed with high accuracy of ± 0.1 μm or less, which is the manufacturing accuracy by the semiconductor process. ing. In such a case, relative position adjustment of the functional unit 15 that performs light emission or light reception of all the four optical waveguides and the photoelectric element 2 is possible by performing position adjustment at two positions at both ends of the four positions. . Further, in the example shown in FIG. 4, the side surface side electrode 18 wraps around the back surface side of the interposer substrate 4.

  With the configuration as described above, the first embodiment of the present invention has the following effects.

  The first effect is that a high-speed signal of 25 Gbps or more can be transmitted between the photoelectric element and the signal amplification element. The first reason is that it is possible to connect the photoelectric element and the signal amplifying element with a short wiring length of less than 0.5 mm by the connection wiring that connects the surface side electrode and the side surface electrode of the interposer substrate. is there. The second reason is that the capacitance existing in the wiring can be reduced by removing the conductive wire 5 used in the assembly process (step S4) of the optical waveguide module.

  The second effect is that a high-speed photoelectric element having a light emitting / receiving region with a small area can be used. The reason is that in the step of adjusting the position in the in-plane direction of the bonding surface between the optical waveguide substrate 1 and the photoelectric element 2 (step S4), the photoelectric conversion element 2 is supplied with power, and the operation characteristics are the best while measuring the operation characteristics. This is because high-accuracy position adjustment can be performed by an active alignment method that determines the optimal position.

The third effect is that a small and low-cost optical waveguide substrate can be used by adopting an optical waveguide made of silicon (Si) having a high refractive index. The reason is that the lens formed on the photoelectric element 2 can efficiently collect the emitted light emitted from the optical waveguide made of silicon (Si) at a wide angle.
[Second Embodiment]
FIG. 5 is a sectional view showing the configuration of an optical waveguide module according to the second embodiment of the present invention. In the second embodiment of the present invention, the interposer substrate 4 and the signal amplification element 6 are connected by an Au wire or an Au ribbon. Au wires and Au ribbons are high-speed signal wirings with excellent connection characteristics, and can support high-speed communication of 25 Gbps or more.
[Third Embodiment]
FIG. 6 is a cross-sectional view showing a configuration of an optical waveguide module according to the third embodiment of the present invention. In the third embodiment of the present invention, the lens 11 and the photoelectric element 2 have different configurations. Photoelectric elements are expensive because they are difficult to manufacture and the number of manufacturers is limited. With the configuration as in the present embodiment, the lens 11 and the photoelectric element 2 can be manufactured separately, so that diversity can be given to the selection of the manufacturer and the material of each component. In addition, lower prices can be expected.
[Fourth Embodiment]
FIG. 7 is a cross-sectional view showing a configuration of an optical waveguide module according to the fourth embodiment of the present invention. In the fourth embodiment of the present invention, the spacer 13 is sandwiched between the optical waveguide substrate 1 and the lens 11. By setting it as such a structure, the lens 11 provided with the convex part can be fixed firmly. Moreover, the optical design of the optical waveguide substrate 1 and the lens 11 can be adjusted by appropriately selecting the transmittance and thickness of the spacer.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and it is also included within the scope of the present invention. Not too long.

DESCRIPTION OF SYMBOLS 1 Optical waveguide board | substrate 2 Photoelectric element 3 Bonding material 4 Interposer board 5 Conductive line 6 Signal amplification element 7 Bonding material 8 Optical waveguide 9 Base 10 Au wire and Au ribbon 11 Lens 13 Spacer 14 Current probe 15 Functional part 16 Current probe electrode (For Signal)
17 Electrode for current probe (for GND)

Claims (10)

An optical waveguide substrate on which an optical waveguide is formed; a photoelectric element that is optically connected to the optical waveguide and transmits and receives an optical signal; an interposer substrate; and a signal amplifying element. An electrode, a side electrode, a connection wiring connecting the surface electrode and the side electrode, the surface electrode is electrically connected to the photoelectric element, and the signal amplification element is An optical waveguide module electrically connected to a side electrode through a bonding material. The optical waveguide module according to claim 1, further comprising a lens having a convex curved shape that is optically connected to the photoelectric element, wherein the convex curved shape of the lens faces the optical waveguide. The interposer substrate has a back surface side electrode, the side surface side electrode, and external wiring connecting the back surface electrode,
The optical waveguide module according to claim 1, wherein the external wiring has a portion that can be cut at least in the vicinity of the side electrode. The optical waveguide module according to any one of claims 1 to 3, wherein the bonding material is a conductive adhesive. The side surface electrode wraps around the back side of the interposer substrate,
5. The method according to claim 1, wherein the bonding material is one of a gold wire and a gold ribbon, and connects the side-side electrode that wraps around to the back surface side and the signal amplification element. The described optical waveguide type module. The optical waveguide module according to claim 3, wherein the external wiring is one of a gold wire and a gold ribbon. A surface side electrode of an interposer substrate having a front surface side electrode, a side surface side electrode, a connection wiring connecting the front surface side electrode and the side surface type electrode, and an external wiring connecting the side surface side electrode and the back surface side electrode through the outside. Electrically connect the photoelectric elements,
Electric power is supplied to the photoelectric element through the external wiring, the operating characteristic of the photoelectric element is measured, and the optimum position where the operating characteristic is the best is determined while adjusting the position of the photoelectric element with respect to the optical waveguide substrate. And
A method for manufacturing an optical waveguide module, wherein the photoelectric element is fixed together with the optical waveguide substrate at the optimum position. 8. The method of manufacturing an optical waveguide module according to claim 7, wherein after the photoelectric element is fixed at the optimum position, the external wiring is cut off at least in the vicinity of the side electrode. 8. The method of manufacturing an optical waveguide module according to claim 7, wherein after the photoelectric element is fixed at the optimum position, the signal amplification element, the side electrode and the side electrode are electrically connected through a bonding material. Forming a lens on the photoelectric element;
The method for manufacturing an optical waveguide module according to any one of claims 7 to 9, wherein the photoelectric element on which the lens is formed is fixed to the surface of the interposer substrate.

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