JP2007199328A - Optical coupling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical coupling device with the transfer efficiency of light enhanced. <P>SOLUTION: The optical coupling device 1 comprises a waveguide embedded substrate 11 on which a waveguide for optical signal transmission is formed extendedly, in parallel with the surface of the substrate; interposers 12, 13 which mount signal medium conversion elements 121, 131 for carrying conversion between an electric signal and a light signal, while directing the operation faces to the waveguide embedded substrate 11 and are fixed to the waveguide embedded substrate; barrier walls 14, 15 which are interposed between the waveguide embedded substrate 11 and the interposers 12, 13 and surround the signal medium conversion elements 121, 131 to form internal spaces 16a, 17a; and light-transmissive sealing agents 16, 17 filled in the internal spaces 16a, 17a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical connection device.

  In recent years, there has been an increasing demand for higher processing speeds in electrical devices, and accordingly, there has been a demand for higher electrical signal transmission speeds in electrical boards built in these electrical devices.

  However, since problems such as electromagnetic interference and propagation delay of electrical signals due to the lengthening of wiring distance become obvious between electrical wirings on an electrical board, in recent years, electrical signals are converted into optical signals, The transmission speed is increased by optical connection for transmission to a waveguide for optical communication embedded inside or on the surface of the optical fiber.

By the way, high transmission efficiency is required for optical connection in order to increase the wiring distance and increase the transmission speed. Here, in Patent Document 1, in order to suppress transmission loss of light, an optical path conversion mirror is provided in the waveguide so as to face a space surrounded by a substrate, so that the optical path conversion mirror is free of dust or the like. Techniques for preventing foreign matter and scratches are disclosed. Patent Document 2 discloses a technique for forming a ring around an optical semiconductor to hermetically seal the optical semiconductor, and according to this, dust is prevented from adhering to the optical semiconductor.
JP 2002-365457 A JP-A-7-134223

  However, in the techniques disclosed in Patent Documents 1 and 2, air is interposed between the waveguide and the optical semiconductor, and a coupling loss occurs due to a difference in refractive index between the air and the waveguide, resulting in an optical transmission loss. Will occur. Moreover, there is a possibility that light transmission loss may increase due to the occurrence of condensation in this portion.

  In view of the above circumstances, an object of the present invention is to provide an optical connection device in which transmission loss of light is suppressed.

An optical connecting device of the present invention that achieves the above object includes a waveguide embedded substrate on which a waveguide for optical signal transmission is formed,
An interposer fixed on the waveguide embedded substrate by mounting a signal medium conversion element responsible for conversion between an electrical signal and an optical signal with the working surface facing the embedded waveguide substrate;
A partition wall interposed between the waveguide embedded substrate and the interposer and surrounding the signal medium conversion element to form an internal space;
And a light-transmitting sealing agent filled in the internal space.

  In the optical connecting device of the present invention, since the internal space surrounding the signal medium conversion element formed by the partition wall interposed between the waveguide embedded substrate and the interposer is filled with the sealant, the waveguide and the signal Air is excluded from the space between the medium conversion element. Therefore, according to the optical connecting device of the present invention, transmission loss of light due to dew condensation or the like between the signal medium conversion element and the waveguide can be suppressed.

  Here, in the optical connection device of the present invention, the interposer may have an injection hole when the sealing agent is injected into the internal space, or in the optical connection device of the present invention. The waveguide embedded substrate may have an injection hole when the sealing agent is injected into the internal space.

  Since the interposer or the waveguide embedded substrate has the injection hole, in the process of manufacturing the optical connection device, first, the interposer and the waveguide embedded substrate are fixed by a normal solder reflow process, and then, A liquid sealant can be injected into the internal space from the injection hole. Therefore, it is easy to manufacture an optical connection device filled with the sealant without a gap.

  In the optical connecting device of the present invention, it is preferable that the sealing agent is a refractive index adjusting agent that improves light transmission efficiency between the signal medium conversion element and the waveguide.

  Filling the internal space with the refractive index compounding agent as the sealant reduces transmission loss between the waveguide and the signal medium conversion element and the sealant, thereby increasing the light transmission efficiency.

  As described above, according to the present invention, an optical connection device with reduced optical transmission loss is realized.

  Embodiments of the optical connection device of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of a multichip module according to a first embodiment of the optical connecting device of the present invention.

  The multichip module 1 shown in FIG. 1 includes a waveguide embedded substrate 11, two interposers 12 and 13 fixed to the waveguide embedded substrate 11, and a waveguide embedded substrate and respective interposers 12 and 13. The packings 14 and 15 interposed therebetween and the sealants 16 and 17 filled in the packings are provided.

  FIG. 2 is a bottom view of the interposer 12 shown in FIG.

  1 and 2, the interposer 12 is a substrate made of epoxy resin. The interposer 12 includes a light emitting element 121 made of a light emitting diode that converts an electrical signal into an optical signal, and a light emitting element 121. A semiconductor element 122 for supplying an electric signal is mounted. A plurality of terminals 123 are formed on the interposer 12, and solder bumps 124 for connecting to the waveguide embedded substrate 11 are provided on the terminals 123. The interposer 12 is formed with wirings (not shown) along the surface and through the interposer 12, and the light emitting element 121, the terminal 123, and the semiconductor element 122 are connected by these wirings.

  On the other hand, the interposer 13 includes a photoelectric element 131 that converts an optical signal into an electric signal and a semiconductor element 132 that receives an electric signal from the photoelectric element 131. The other configuration of the interposer 13 is the same as that of the interposer 12, and a plurality of terminals 133 and solder bumps 134 are provided. Each of the light emitting element 121 and the photoelectric element 131 corresponds to an example of the signal medium conversion element of the present invention that performs conversion between an electric signal and an optical signal.

  The semiconductor element 122 mounted on the interposer 12 and the semiconductor element 132 mounted on the interposer 13 realize the function as the multichip module 1 while performing communication using optical signals.

  The waveguide embedded substrate 11 is a substrate for fixing the interposers 12 and 13, and a waveguide 111 for optical signal transmission is formed on the waveguide embedded substrate 11. The waveguide 111 extends inside the waveguide embedded substrate 11 in parallel with the direction in which the waveguide embedded substrate 11 spreads, bends at 90 ° in the vicinity of both end portions 111a and 111b, and then embeds the waveguide from there. The shape extends to the surface of the substrate 11. In portions where the waveguide 111 is bent, mirrors 112a and 112b that reflect light are formed, and an optical signal is transmitted along the waveguide path that is bent halfway. The optical signal transmission waveguide 111 and the mirrors 112a and 112b can be formed on the waveguide embedded substrate 11 by a known method, and the description thereof is omitted.

  The interposer 12 is fixed to the waveguide embedded substrate with the working surface 121a perpendicular to the direction in which the light emitting element 121 emits an optical signal facing the waveguide embedded substrate 11, and the interposer 13 is also photoelectrically connected. The working surface 131a perpendicular to the direction in which the element 131 receives the optical signal is fixed to the waveguide embedded substrate in a state where the element 131 faces the waveguide embedded substrate 11. For this reason, an optical signal emitted from the light emitting element 121 and incident from one end 111a of the waveguide 111 travels in the waveguide 111 while being bent by 90 ° by being reflected by the mirrors 112a and 112b, and the other end. The photoelectric element 131 is irradiated from the portion 111b. Thereby, the optical connection via the light emitting element 121 and the photoelectric element 131 is performed between the semiconductor element 122 and the semiconductor element 132.

  The packings 14 and 15 are circular ring-shaped members made of heat-resistant silicon resin, and are disposed so as to be interposed between the waveguide embedded substrate 11 and the interposers 12 and 13, respectively. The packing 14, together with the waveguide embedded substrate 11 and the interposer 12, forms an internal space 16 a that surrounds the light emitting element 121. The internal space 16a is filled with a sealant 16. The packing 15 also forms an internal space 17a surrounding the photoelectric element 131 by the waveguide embedded substrate 11 and the interposer 13, and the internal space 17a is filled with a sealing agent 17. The packings 14 and 15 correspond to an example of a partition wall according to the present invention.

  As the sealant 16, a refractive index compounding agent that has optical transparency and improves the light transmission efficiency between the light emitting element 121 and the waveguide 111 is used. More specifically, the refractive index preparation agent in the present embodiment is matching oil (index matching oil: refractive index matching oil). As the matching oil, an oil whose main component is ethylene glycol and whose components are adjusted so as to improve the light transmission efficiency between the light emitting element 121 and the photoelectric element 131 and the waveguide 111 is selected. Specifically, the components are adjusted so that the refractive index of the waveguide 111 approximates the refractive index of the matching oil. For example, when the refractive index of the waveguide 111 is 1.5, the refractive index of the matching oil is adjusted to be 1.5. The component of the matching oil may basically be any component that has little loss with respect to the wavelength of the optical signal, and the main component of the matching oil may be, for example, silicone oil.

  In the waveguide embedded substrate 11, when the multichip module 1 is manufactured, a pair of injection holes 116a and 116b when a liquid sealing agent is injected into the internal space 16a, and a liquid sealing in the internal space 17a. A pair of injection holes 117a and 117b are formed when the agent is injected. The injection holes 116a, 116b, 117a, and 117b are formed by first forming a slit having a bottom surface in the same plane as the injection holes 116a, 116b, 117a, and 117b in the waveguide embedded substrate 11, and thereafter, from above the slit. A plate-like member is fitted as a ceiling portion and bonded to the waveguide embedded substrate 11, and a hole reaching the bottom surface of the slit is formed at both ends of the plate-like member. Note that the method of forming the injection hole is not limited to this. For example, a resist is formed in a portion corresponding to the bottom of the injection holes 116a, 116b, 117a, and 117b of the waveguide embedded substrate 11, and a semiconductor process is formed thereon. Alternatively, the semiconductor layer may be formed by removing the resist.

  Here, the assembly process of the multichip module 1 will be described.

  First, the light emitting element 121, the semiconductor element 122, and the packing 14 are attached to the interposer 12, and the solder bump 124 is attached on the terminal 113 (see FIG. 2). Similarly, the photoelectric element 131, the semiconductor element 132, the packing 15, and the solder bump 134 are attached to the interposer 13. Thereafter, the interposer 12 and the interposer 13 are placed on the waveguide embedded substrate 11 in which the waveguide 111 and the injection holes 116a, 116b, 117a, and 117b are formed, and a solder reflow process is performed. The solder bumps 124 and 134 are melted by the solder reflow process. At this time, the packings 14 and 15 are crushed in the vertical direction by the weight of the interposers 12 and 13 themselves and are in close contact with the waveguide embedded substrate 11 without a gap. Thereby, internal spaces 16a and 17a are formed. Further, the packings 14 and 15 prevent solder flux and dust from adhering to the waveguide 111, the light emitting element 121, and the photoelectric element 131. After the solder reflow process, the solder bumps 124 and 134 are solidified to fix the interposers 12 and 13 to the waveguide embedded substrate 11, and the terminals 114 and 115 of the waveguide embedded substrate 11 and the terminals of the interposer 12. 123 and the terminal 133 of the interposer 13 are connected to each other.

  After the solder reflow, matching oil is injected into the internal spaces 16a and 17a from the injection holes 116a, 116b, 117a, and 117b. In the state where one injection hole 116a is immersed in the matching oil, the air in the internal space 16a is sucked from the other injection hole 116b by a vacuum pump or the like, so that the matching oil is injected from the injection hole 116a and the internal space 16a is filled without gaps. The matching oil is filled in the internal space 17a in the same manner as the internal space 16a. After injecting the matching oil, the lids 118a, 118b, 119a, and 119b made of resin are formed at the inlets of the injection holes 116a, 116b, 117a, and 117b, respectively, thereby closing the injection holes 116a, 116b, 117a, and 117b. It is. In this way, the multichip module 1 filled with the sealing agents 16 and 17 made of matching oil is completed.

  In the multichip module 1 assembled in this way, the internal space surrounding the light emitting element 121 or the photoelectric element 131 formed by the packings 14 and 15 interposed between the waveguide embedded substrate 11 and the interposers 12 and 13. 16 a is filled with the sealing agent 16, and air is excluded from between the waveguide 111 and the light emitting element 121 or the photoelectric element 131. Therefore, according to the multichip module 1, the loss of light due to condensation is suppressed. Further, since the waveguide embedded substrate 11 has the injection holes 116a and 116b, after the interposers 12 and 13 and the waveguide embedded substrate 11 are fixed by ordinary solder reflow in the manufacture of the multichip module 1, Sealant can be injected into the internal spaces 16a and 17a from the injection holes 116a and 116b. Therefore, the multichip module 1 in which the sealing agent is filled between the waveguide 111 and the light emitting element 121 or the photoelectric element 131 without a gap can be easily manufactured. Moreover, since the sealing agents 16 and 17 are matching oils that improve the light transmission efficiency, the light transmission efficiency between the waveguide 11 and the light emitting element 121 or the photoelectric element 131 is increased.

  Next, a second embodiment of the present invention will be described. In the following description of the second embodiment, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 3 is a cross-sectional view showing a multichip module according to the second embodiment of the present invention.

  In the multichip module 2 shown in FIG. 3, the injection holes 222 a, 222 b, 231 a, and 231 b are formed not in the waveguide embedded substrate 21 but in the interposer 22 and the interposer 23. And different.

  FIG. 4 is a bottom view of the interposer 22 shown in FIG.

  As shown in FIG. 4, the interposer 22 is formed with a pair of injection holes 222a and 222b when a liquid sealing agent is injected into the internal space 16a when the multichip module 2 is manufactured. The injection holes 222a and 222b are holes having a shape that penetrates the interposer 22 in a straight line and can be easily formed with a drill or the like. Unlike the injection holes 116a and 116b in the multichip module 1 of FIG. There is no need to add or form a cavity with resist. Therefore, according to the multichip module 2 of the second embodiment, in addition to the effects of the multichip module 1 of the second embodiment, the manufacture of the multichip module is further facilitated.

  In the above-described embodiment, the material of the packings 14 and 15 has been described as, for example, a heat-resistant silicon resin having elasticity, but is not limited thereto. The partition wall referred to in the present invention may be made of other materials as long as the internal space is separated from the outside.

  Moreover, although the example of matching oil was demonstrated as sealing agent 16 and 17, it is not restricted to this, The material of sealing agent 16 and 17 of this invention can be liquefied at high temperature and can be inject | poured from an injection hole. Further, it may be a resin that solidifies at room temperature, or may be a resin that is liquid at the time of pouring from the pouring hole and solidifies after a predetermined time. The sealant of the present invention may be, for example, a resin such as polycarbonate and PET. Since these resins are higher than air and have a refractive index closer to the refractive index of the waveguide, not only the loss due to condensation is suppressed, but also the light transmission efficiency is improved.

  In this embodiment, an example of a multi-chip module has been described. However, the present invention is not only applied to a multi-chip module, but can also be applied to, for example, an optical connection device having a single-chip configuration connected to an optical cable. It is.

It is sectional drawing of the multichip module of 1st Embodiment of the optical connection apparatus of this invention. It is a bottom view of an interposer. It is sectional drawing which shows the multichip module of 2nd Embodiment of this invention. FIG. 4 is a bottom view of the interposer shown in FIG. 3.

Explanation of symbols

1, 2 Multi-chip module (optical connection device)
11, 21 Waveguide embedded substrate 12, 13, 22, 23 Interposer 14, 15 Packing (partition wall)
16a, 17a Internal space 16, 17 Sealant 111 Waveguide 111a, 111b End portion 116a, 116b, 117a, 117b Injection hole 222a, 222b, 231a, 231b Injection hole 121 Light emitting element (signal medium conversion element)
121a Working surface 131 Photoelectric element (signal medium conversion element)
131a Working surface 122,132 Semiconductor element

Claims (4)

A waveguide embedded substrate in which a waveguide for optical signal transmission is formed;
An interposer fixed to the waveguide-embedded substrate by mounting a signal medium conversion element responsible for conversion between an electrical signal and an optical signal in a state in which the working surface faces the waveguide-embedded substrate;
A partition wall interposed between the waveguide embedded substrate and the interposer and surrounding the signal medium conversion element to form an internal space;
An optical connection device comprising: a light-transmitting sealant filled in the internal space.   The optical connection device according to claim 1, wherein the interposer has an injection hole when the sealing agent is injected into the internal space.   2. The optical connection device according to claim 1, wherein the waveguide embedded substrate has an injection hole when the sealing agent is injected into the internal space.   The optical connecting device according to claim 1, wherein the sealing agent is a refractive index compounding agent that improves light transmission efficiency between the signal medium conversion element and the waveguide.

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