JP2007057976A - Optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce manufacturing cost, to contrive miniaturization, and to increase reliability and mass productivity. <P>SOLUTION: This is an optical module 200 to be installed on a substrate 106 and is equipped with: a peripheral IC 214 electrically connected with the substrate 106; and a photoelectric element 212 that is electrically connected to the peripheral IC 214, that is provided with circuit faces 212d1, 212e1 constituting at least either a light receiving part for receiving an optical signal or a light emitting part for transmitting an optical signal, and that is optically connected with an optical fiber array 202. The photoelectric element 212 is arranged so that the circuit faces 212d1, 212e1 may come to the top side. Also, the body of the element 212 is covered, from the circuit faces 212d1, 212e1 to the side and to the bottom of the body, with a flexible film 216 in which a wiring 212b is formed for electrically connecting the circuit faces 212d1, 212e1 to the peripheral IC 214. The element is electrically connected to the peripheral IC 214 on the bottom side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical module that optically connects a photoelectric element and an optical fiber.

  In recent years, the speeding up of devices such as LSI has made remarkable progress. In particular, a 1 GHz product, which was considered impossible about 10 years ago in CMOS, has been put into practical use, and a 10 GHz product has been put into practical use at the most advanced level. Under such circumstances, there is a limit to guaranteeing “signal quality” in the conventional mounting method using only the motherboard wiring or the electrical method in which the connection between the motherboards is performed using an electric cable connector. This is a general recognition of engineers regarding interconnection.

  As a means for solving this problem, it is expected to replace the electrical interconnection with the optical interconnection. However, it is not practical in terms of size, cost, power consumption, etc. to apply the conventional network backbone optical transmission technology for information transmission of several kilometers to several hundred kilometers to “optical interconnection”. There is no practical value in the field of interconnection.

  For this reason, high-speed signals are limited to the LSI package interposer without going through the mounting board, and the electrical wiring length is shortened, converted into an optical signal within the interposer, and used as an external input / output. Has been. However, any of the methods such as a method using a connector and a method of soldering an optical module has many problems in terms of cost.

  As an optical module proposed to replace electrical interconnection with optical interconnection, an optical module described in Patent Document 1 is known. 12A and 12B are schematic configuration explanatory views of the optical module described in Patent Document 1. FIG. As shown in FIG. 12A, the optical module includes an optical fiber 308, an optical element that transmits and receives an optical signal, and a connection pin 309 that is electrically connected to the optical element. As shown in FIG. 12B, the interposer 302 and the optical module 307 are electrically connected by mechanical contact between the connection pin 309 and the jack 310.

  Further, Patent Document 2 discloses an optical module aimed at downsizing and cost reduction. FIG. 13 is a perspective view illustrating a schematic configuration of the optical module described in Patent Document 2, and FIG. 14 is a cross-sectional view illustrating the schematic configuration of the optical module. As shown in FIG. 13, the optical module described in Patent Document 2 includes electrical wiring 412 and element mounting on a main surface 410-1 of a support substrate 410 on which a semiconductor element 411 (not shown in FIG. 13) is mounted. A recess 414 is formed at the end of the main surface 410-1, and the electrical wiring 412 extends to the inclined surface 415 of the recess 414. Further, as shown in FIG. 14, a semiconductor element 411 having a light receiving region 411-1 is mounted on the electrode pattern 413 by solder or silver paste, and the central axis of the optical waveguide of the optical transmission line 430 and the light receiving region 411-1 Arranged so that the central axes coincide. With such a configuration, when the electrical wiring 412 and the external connection wiring 421 are brought into contact with each other by the solder material 422, the probability that the solder material 422 causes a short-circuit accident with the adjacent wiring is greatly reduced. Further, since the connection is completed without requiring any special adjustment, it is possible to increase the throughput and to realize at a low cost.

Furthermore, what was described in patent document 3 as another optical module is also known. FIG. 15A is a top view illustrating a schematic configuration of the optical module described in Patent Document 3, and FIG. 15B is a cross-sectional view illustrating the schematic configuration of the optical module. As shown in FIG. 15A, the optical module described in Patent Document 3 is provided with a guide hole 524 into which the guide pin 520 is to be inserted in either one of the transparent substrate 510 and the optical transmission line support member 518. The optical alignment is performed easily with high accuracy. As shown in FIG. 15B, an electrode formed on the circuit surface of the photoelectric element 512 is connected to the lower surface of the transparent substrate 510, and the photoelectric element 512 is optically coupled to the tape fiber 550 through the transparent substrate 510. It is connected.
JP 2004-253456 A JP 2005-44966 A JP 2004-240220 A

However, the optical module described in Patent Document 1 does not disclose a specific structure of photoelectric conversion.
Further, in the optical module described in Patent Document 2, since the support substrate 410 is arranged vertically and connected to the substrate at the edge portion, the electrical connection portion is close to point connection, and it is difficult to ensure reliability. There are also problems. Furthermore, although the angle between the main surface 410-1 and the inclined surface 415 on the support substrate 410 is larger than 90 degrees, the electric wiring 412 is formed across the substantially flat main surface 410-1 and the inclined surface 415. Therefore, there is a problem that disconnection is likely to occur at the boundary between the main surface 410-1 and the inclined surface 415. Further, since the semiconductor element 411 is exposed, there is a problem that dust or the like enters the circuit surface of the semiconductor element 411. In order to prevent this, it is conceivable to form a resin coat on the surface of the semiconductor element 411. However, there is a possibility that the optical signal transmission / reception may be hindered due to impurities contained in the resin coat itself or unevenness of the surface of the resin coat. is there.
Also, in the optical module described in Patent Document 3, an underfill process or the like is required for the connection portion due to the configuration of the bare chip, which makes the manufacturing work and the like troublesome. Furthermore, not only the transparent substrate on which the bare chip is mounted, but also a CP substrate for electrically connecting the transparent substrate and the motherboard, and a grounding mechanism for impedance matching in the transparent substrate and the CP substrate are also required. However, there is a problem that the manufacturing cost increases with the increase in size.

  According to the present invention, an optical module provided on a substrate, a semiconductor element electrically connected to the substrate, a light receiving unit electrically connected to the semiconductor element and receiving an optical signal, and the optical signal And a photoelectric element optically connected to an optical fiber, the photoelectric element being arranged so that the circuit surface is on the upper side. And the body of the photoelectric element is covered from the circuit surface to the lower surface via the side surface by a covering member in which wiring for electrically connecting the circuit surface and the semiconductor element is formed, An optical module is provided that is electrically connected to the semiconductor element at the lower surface.

  In this optical module, there is no need to provide a wiring wire protruding from the circuit surface of the photoelectric element or to provide a transparent substrate that is electrically connected to the circuit surface and covers the circuit surface side. That is, the electrical connection part with the semiconductor element side is formed in the lower part of the photoelectric element, and the upper part of the circuit surface is opened. Thereby, a member to which the optical fiber is fixed can be brought close to the circuit surface, and an optical member such as a lens for transmitting and receiving an optical signal between the optical fiber and the photoelectric element becomes unnecessary. As a result, the number of parts can be reduced, and the number of processes in the assembly process and the inspection process can be reduced, and the manufacturing cost can be drastically reduced as compared with a lens having an optical member such as a lens. Further, the module can be reduced in size by omitting the optical member.

  The above configuration requires a technical device for electrically connecting the circuit surface of the photoelectric element and the semiconductor element. In order to realize this, by forming the wiring along the surface of the photoelectric element, a stable electrical connection between the lower part of the photoelectric element and the semiconductor element side becomes possible. In other words, there is no risk of disconnection or the like due to stress concentration in the wiring by forcibly pulling the wiring to the bottom of the module, as in the case where the wiring is formed on the module substrate itself. Reliability is dramatically improved.

  According to the optical module of the present invention, the manufacturing cost of the module can be reduced and the size can be reduced, and the reliability and mass productivity can be remarkably improved, which is extremely advantageous in practical use.

  A preferred embodiment of an optical module of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 shows an embodiment of the present invention and is a schematic explanatory diagram of a mother board in which module substrates are connected using an optical module.
As shown in FIG. 1, the motherboard 100 is connected with two module substrates 106 and 108 on which LSIs 102 and 104 as high-speed circuit units are mounted. A ball grid array (hereinafter referred to as “BGA”) 110 is formed below each of the module substrates 106 and 108 and is electrically connected to a signal wiring 112, a power supply wiring 114, and the like formed on the motherboard 100. The power supply wiring 114 may be a ground wiring. Each module substrate 106, 108 is mounted with an optical module 200, and each optical module 200 has an optical fiber array 202 (not shown in FIG. 1) that transmits and receives optical signals to each other. Hereinafter, the optical module 200 which is a characteristic configuration of the present invention will be described on one module substrate 106 side of the two module substrates 106 and 108. The difference between the optical module 200 on the one module board 106 side and the other module board 108 side is the optical fiber extraction direction and the arrangement position of each member related thereto. To do.

FIG. 2 is an external perspective view of the optical module.
As shown in FIG. 2, the optical module 200 includes a substantially box-shaped submodule 204 in which a peripheral IC 214 (not shown in FIG. 2) and a photoelectric element 212 (not shown in FIG. 2) are arranged, And a substantially box-shaped fiber connector 206 on which an optical fiber array 202 is disposed, which is detachably provided on the module 204. The fiber connector 206 functions as a so-called passive connector. The optical module terminal 210 of the submodule 204 is connected to the module substrate 106, and electrical signals can be transmitted and received between the optical module 200 and the motherboard 100.
The “photoelectric element” is generally used as a general term for an element that converts an optical signal into an electric signal, that is, a photoelectric conversion element, and an element that converts an electric signal into an optical signal, that is, an electric-optical conversion element. Many. In this specification, the term “photoelectric element” is used as a generic term for both unless otherwise specified. Therefore, the term “photoelectric element” refers to any one or both of the above.

FIG. 3 is a longitudinal sectional view of the optical module when the optical module of FIG. 2 is cut in the AA direction, and is a diagram showing a relationship with the module substrate and the like. FIG. 4 is a longitudinal sectional view of the optical module in a state where the sub module and the fiber connector are separated when the optical module of FIG. 2 is cut in the AA direction, and is a diagram showing a relationship with the module substrate and the like.
As shown in FIGS. 3 and 4, the optical module 200 includes a peripheral IC 214 as a semiconductor element that is electrically connected to the module substrate 106, and a light receiving unit that is electrically connected to the peripheral IC 214 and receives an optical signal. A photoelectric element 212 having circuit surfaces 212d1 and 212e1 forming at least one of light-emitting portions that transmit an optical signal, an optical fiber array 202 extending substantially parallel to the module substrate 106 and optically connected to the photoelectric element 212, It has.

FIG. 5 is a cross-sectional view of the optical module in which the optical module is cut along the BB cross section in FIG. 2 and the cut surface is viewed from above. Here, FIG. 5 does not show a cross section of the main body portion of the fiber connector for the sake of explanation.
As shown in FIG. 5, the photoelectric element 212 includes both VCSEL (Vertical Cavity Surface Emitting Laser) 212d and PIN-PD (PIN type photodiode) 212e. In the present embodiment, the photoelectric element 212 includes one VCSEL 212d that is a light emitting element and one PIN-PD 212e that is a light receiving element. And since the circuit surface is formed for every light receiving element or light emitting element, when it has two or more light receiving elements or light emitting elements, a photoelectric element will have two or more circuit surfaces. In the present embodiment, the photoelectric element 212 has a circuit surface 212d1 of the VCSEL 212d and a circuit surface 212e1 of the PIN-PD 212e. The VCSEL 212d has a function of transmitting an electrical signal as an optical signal, and the circuit surface 212d1 forms a light emitting unit. The PIN-PD 212e has a function of receiving an optical signal and converting it into an electrical signal, and the circuit surface 212e1 serves as a light receiving portion. As shown in FIG. 5, the VCSEL 212 d and the PIN-PD 212 e are arranged in parallel to the module substrate 106.

  As shown in FIGS. 3 and 4, the peripheral IC 214 of the optical module 200 is formed in a chip shape and is arranged substantially parallel to the module substrate 106, and serves as both a receiver and a driver. The peripheral IC 214 is covered from the upper part to the lower surface via the side surface by the covering member on which the wiring 214b is formed. In the present embodiment, the covering member is a flexible film 216 whose main component is polyimide. As shown in FIG. 5, the peripheral IC 214 forms a driver 214d below the VCSEL 212d of the photoelectric element 212, and forms a receiver 214e below the PIN-PD 212e.

  The photoelectric element 212 is arranged so that the circuit surfaces 212d1 and 212e1 are on the upper side, and the circuit surface 212d1 is formed by a flexible film 216 on which wiring 212b for electrically connecting the circuit surfaces 212d1 and 212e1 and the peripheral IC 214 is formed. 212e1 through the side surface to the lower surface. The photoelectric element 212 is electrically connected to the peripheral IC 214 on the lower surface. In this embodiment, the photoelectric element 212 and the peripheral IC 214 are stacked and both are in a so-called cascade connection.

Here, a method for manufacturing the photoelectric element 212 will be described. 6A is a cross-sectional explanatory view of the photoelectric element before assembly, and FIG. 6B is a cross-sectional explanatory view of the photoelectric element after assembly.
As shown in FIG. 6A, a hole 220 for connecting to the element body 218 of the photoelectric element 212 is formed on one surface of the flat flexible film 216 in which the wiring 212b made of copper is arranged on the inside, and on the other surface. A hole 222 for mounting the external terminal 230 is formed. Here, both the signal wiring and the ground wiring are formed in the wiring 212b. As shown in FIG. 6A, the wiring 212b is formed so that the element main body 218 is not located directly above the formation portion of the circuit surfaces 212d1 and 212e1. Thereby, light reception or light emission on the circuit surfaces 212d1 and 212e1 is not hindered. In FIG. 6A, the wiring 212b is not formed between the bumps 228, which will be described later, and is cut out in a predetermined direction (depth direction in FIG. 6) just above the circuit surface 212d1 (directly below in the figure). It has a cross-sectional shape. Then, electrodes 224 and 226 electrically connected to the wiring 212b are formed in the holes 220 and 222, respectively. The electrodes 224 and 226 may be made of, for example, Au on a Ni base or made of a solder material, and the material and the like can be arbitrarily selected.

  Then, the bump 228 is mounted on the element body 218 and connected to the electrode 224 of the hole 220 formed on one surface of the flexible film 216. This connection is realized by, for example, crimping. Here, the bump 228 is made of, for example, Au, and the material and the like can be arbitrarily selected.

  From this state, as shown in FIG. 6B, the flexible film 216 is heated and softened, bent along the element body 218, and thermocompression-bonded to the element body 218, thereby completing a CSP (chip_size_package). In this embodiment, the flexible film 216 is made of a resin whose main component is polyimide, and has a property of being softened at about 200 ° C. and capable of being bonded. Here, FIG. 6B shows the external terminal 230 formed on the lower surface side of the element body 218. In the present embodiment, the external terminal 230 is composed of BGA. As shown in FIG. 3, the photoelectric element 212 is arranged in the submodule 204 so that the external terminal 230 is connected to the upper surface of the peripheral IC 214.

  As described above, the photoelectric element 212 has the flexible film 216 including the pattern of the wiring 212b around the element body 218. As a result, the input / output terminals of the circuit surfaces 212d1, 212e1 are other than the circuit surfaces 212d1, 212e1. Can be formed. Here, the flexible film 216 of the photoelectric element 212 is made of a light transmitting material and does not hinder the transmission and reception of optical signals. Thereby, the reliability of the wiring 212b portion is improved as compared with the case where the bare chip is connected to the substrate side by wire bonding. Furthermore, the photoelectric element 212 can be handled as a package product including the wiring 212b portion, delivery by KGD (Known Good Die) is possible, and a good product can be applied during assembly. This improves the product yield. In addition, since the ground wiring is built together with the signal wiring in the wiring 212b portion of the photoelectric element 212, impedance matching can be performed easily and easily, compared to the single wiring of the signal wiring like the conventional wire bonding, Signal quality can be dramatically improved.

  In the present embodiment, the peripheral IC 214 is also manufactured by the same method as that for the photoelectric element 212. FIG. 7 is a cross-sectional explanatory diagram of a peripheral IC. As shown in FIG. 7, for the peripheral IC 214, the external terminal 230 is formed not only on the lower surface side of the element body 218 but also on the upper surface side. The external terminal 230 on the upper surface side of the peripheral IC 214 is connected to the external terminal 230 of the photoelectric element 212, and the external terminal 230 on the lower surface side is connected to the interposer 232 having the optical module terminal 210. That is, an interposer 232 in which an optical module terminal 210 connected to the module substrate 106 is formed is connected to the lower portion of the peripheral IC 214, and the interposer 232, the peripheral IC 214, and the photoelectric element 212 form a system-in-package. Since the photoelectric element 212 and the external terminal 230 of the peripheral IC 214 are configured by BGA, they can be connected together by reflow.

  In the present embodiment, the submodule 204 includes a connector holder 234 that houses the photoelectric element 212 and the peripheral IC 214 and forms an outer shell. The connector holder 234 is formed by, for example, molding or metal molding, and is fixed to the interposer 232 by bonding or soldering. The connector holder 234 is connected to the housing 236 of the fiber connector 206.

  Next, mounting of the optical fiber array 202 on the fiber connector 206 will be described. In the present embodiment, twelve optical fibers are aligned to constitute the optical fiber array 202. As shown in FIG. 4, the optical fiber array 202 is set in a V groove (not shown) of the housing 236 and then fixed with an array fixing piece 238. Here, a guide pin method is used as a method of positional deviation control. A mirror 240 is installed in the depth direction of the V-groove. The mirror 240 is interposed between the optical fiber array 202 and the photoelectric element 212 to reflect an optical signal, and optically connects the optical fiber array 202 and the photoelectric element 212. Thus, the optical signal is configured to be substantially parallel to the module substrate 106 on the optical fiber array 202 side and to be substantially perpendicular to the module substrate 106 on the photoelectric element 212 side.

  Further, as shown in FIG. 4, the housing 236 is formed with a plurality of pins 236 a protruding downward, and each pin 236 a is configured to fit into a hole 234 a formed in the connector holder 234. Each pin 236a is formed so as to protrude downward, and by moving the fiber connector 206 up and down with respect to the submodule 204, each pin 236a is inserted into and removed from each hole 234a. The submodule 204 and the fiber connector 206 are positioned relative to each other by the pins 236a and the holes 234a (see FIG. 3).

  In the optical module 200 configured as described above, when functioning as a transmitter, the output of the high-speed or ultra-high-speed electric signal on the module substrate 106 is in the order of the optical module terminal 210, the interposer 232, the peripheral IC 214, and the photoelectric element 212. Communicated. Then, after the electrical signal is converted into an optical signal by the photoelectric element 212, the optical signal is output to the optical fiber array 202 via the mirror 240. In this embodiment, the photoelectric element 212 having a VCSEL 212d is used, and the peripheral IC 214 having a laser diode driver 214d is used.

  When functioning as a receiver, the optical signal received from the optical fiber array 202 is input to the photoelectric element 212 via the mirror 240 and converted into an electrical signal. The electrical signal output of the photoelectric element 212 is transmitted in the order of the peripheral IC 214, the interposer 232, the optical module terminal 210, and the module substrate 106. In the present embodiment, a photoelectric element 212 having a PIN-PD 214e is used, and a peripheral IC 214 having a preamplifier receiver 214e is used.

  According to the optical module 200 of the present embodiment, wiring wires protruding from the circuit surfaces 212d1 and 212e1 of the photoelectric element 212 are provided, or are electrically connected to the circuit surfaces 212d1 and 212e1 to cover the circuit surfaces 212d1 and 212e1 side. There is no need to provide a transparent substrate. That is, the electrical connection part with the optical module terminal 210 side is formed in the lower part of the photoelectric element 212, and the upper side of the circuit surfaces 212d1 and 212e1 is opened. As a result, a member to which the optical fiber array 202 is fixed can be brought close to the circuit surfaces 212d1 and 212e1, and an optical member such as a lens for transmitting and receiving an optical signal between the optical fiber array 202 and the photoelectric element 212 is unnecessary. Become. As a result, the number of parts can be reduced, and the number of processes in the assembly process and the inspection process can be reduced, and the manufacturing cost can be drastically reduced as compared with a lens having an optical member such as a lens. Further, the module can be reduced in size by omitting the optical member.

More specifically, in the conventional configuration of the edge emitting laser diode and SM fiber generally used for long-distance communication as an optical transmission device, the emission angle of the emitted light is relatively large, for example, a loss of 0.5 dB or less is assumed. In this case, the allowable displacement of the optical axis is within about 1 μm. In addition to this, the use of a lens has become essential because the optical fiber cannot be sufficiently close to the circuit surface.
In the present embodiment, a VCSEL having a circular emission light and a relatively small emission angle is employed, and the allowable positional deviation of the optical axis is relaxed within about 5 μm by the combination with the MM fiber. The optical fiber array 202 is made sufficiently close to the circuit surfaces 212d1 and 212e1 at a distance of about 200 μm, so that no lens is required.

  Further, since the wiring 212b is formed from the circuit surfaces 212d1 and 212e1 to the lower part along the surface of the photoelectric element 212, stable electrical connection is possible between the lower part of the photoelectric element 212 and the optical module terminal 210 side. That is, there is no risk of disconnection or the like due to stress concentration in the wiring by forcibly pulling the wiring to the bottom of the module, as in the case where the wiring is formed on the vertical module substrate itself. Electrical reliability is greatly improved.

  Further, according to the optical module 200 of the present embodiment, since the photoelectric element 212 and the peripheral IC 214 are cascade-connected, the submodule 204 can be configured in a small size. In particular, since the wiring 214b is formed along the surface of the peripheral IC 214, the photoelectric element 212 and the peripheral IC 214 can be formed thin, and the amount of protrusion upward from the module substrate 106 can be reduced. .

Further, according to the optical module 200 of the present embodiment, since the sub-module 204 and the fiber connector 206 are detachable, the optical fiber array 202 and the photoelectric element 212 can be separated, which is advantageous for maintenance, handling, and the like. It is. Moreover, since the attaching / detaching mechanism is configured by the pin 236a formed on one side and the hole 234a formed on the other side, the fiber connector 206 can be inserted into and removed from the submodule 204, and the fiber connector 206 is moved up and down. Desorption with the submodule 204 is realized, and the desorption operation can be performed very easily.
Here, since the circuit surfaces 212d1 and 212e1 of the photoelectric element 212 are close to the optical fiber array 202 side, even if an error occurs when the submodule 204 and the fiber connector 206 are detachably attached, the circuit surface 212d1 , 212e1 can accurately input / output optical signals. That is, even if it is detachable, it does not hinder signal input / output.

  Moreover, according to the optical module 200 of this embodiment, since the wirings 212b and 214b are covered with the flexible film 216, the mechanical protection of the wirings 212b and 214b can be accurately performed. Further, in addition to mechanical protection, dust can be prevented from entering the circuit surfaces 212d1 and 212e1, and even if dust adheres to the surface of the flexible film 216, it can be easily and easily removed. Furthermore, there is no possibility that impurities are mixed in the flexible film 216, and since it is adhered flatly along the element body 218, the surface of the flexible film 216 is not formed with irregularities, which is suitable for transmission and reception of optical signals. is there.

Also, according to the optical module 200 of the present embodiment, the length of the wiring 212b can be made shorter than that of the conventional one. Therefore, when the wiring 212b is modeled and the signal quality is simulated, the model is reduced. Calculation is relatively easy.
Furthermore, in the prior art, when the wire is a single wire for signal wiring, a ground structure must be provided for impedance matching, which also increases the size of the module and makes impedance matching easy and easy. I can't. In this embodiment, such a problem is also solved.

  Further, according to the optical module 200 of the present embodiment, since high-speed signals are processed in the module substrate 106, the LSI 102 can be used without performing serial / parallel conversion or the like, and the gate usage rate can be increased. In addition, the number of terminals of the LSI 102 can be reduced, and the module-side substrate can be lowered to reduce the cost.

  Further, according to the present embodiment, since the optical module 200 can be inserted into and removed from the mother board 100, even a person who does not have technical knowledge of electrical transmission or optical transmission can easily and easily interconnect between devices. Can be configured.

  In addition, according to the present embodiment, since the high-speed signal is separated from the motherboard 100, it is easier to find the cause at the time of malfunction as compared with the case where the low-speed and high-speed signals are mixed. In addition, even if it is necessary to re-create, any one of the motherboard 100 side and the optical module 200 side may be created, which is advantageous in terms of quality, cost, delivery date, and the like. Further, the problem of unnecessary radiated radio waves caused by wiring conventionally formed on the mother board 100 is solved by a combination of downsizing by modularization and an optical interface. Here, even for a signal of about 10 GHz, it has been experimentally confirmed that the signal quality is guaranteed by setting the size of the module substrate 106 to about 5 cm or less.

  In summary, according to the present embodiment, the module manufacturing cost can be reduced and the module can be reduced in size, and the reliability and mass productivity can be significantly improved, which is extremely advantageous in practical use.

  In the above embodiment, the photoelectric element 212 is composed of the VCSEL 212d and the PIN-PD 212e. However, as shown in FIG. 8, the photoelectric element 212 may be composed of either one. FIG. 8 shows a modified example of the embodiment, in which (a) shows that the photoelectric element 212 is composed only of the VCSEL 212d, and (b) shows that the photoelectric element 212 is composed only of the PIN-PD 212e. . Further, the peripheral IC 214 may function only as the driver 214d when the photoelectric element 212 is a VCSEL 212d as shown in FIG. 8A, or the photoelectric element 212 is PIN− as shown in FIG. 8B. In the case of the PD 212e, it may function only as the receiver 214e. That is, the peripheral IC 214 may form at least one of the receiver 214e and the driver 214d. Here, FIG. 8 shows an optical fiber array 202 in which four optical fibers are aligned. As described above, the number of optical fibers in the optical fiber array can be appropriately changed according to the specification and the like, and it is needless to say that the number of optical fibers may be one.

  In the above embodiment, the flexible film 216 including the wiring 212b made of copper is bent. However, the flexible film 216 having the wiring 212b formed on the surface may be bent. In the above embodiment, the wiring 212b is a single layer, but the wiring 212b may be a multilayer. In short, the film 216 on which wiring for electrically connecting the circuit surfaces 212d1, 212e1 and the optical module terminal 210 is formed covers the surface of the element body 218 from the circuit surfaces 212d1, 212e1 to the end surface 212c. It only has to be.

  In the above embodiment, the element body 218 is covered only with the flexible film 216. For example, as shown in FIG. 9, a heat sink 238 is provided on the element body 218 on the opposite side of the circuit surfaces 212d1, 212e1. They may be arranged adjacent to each other and covered with a flexible film 216 together with the element body 218. As a result, the rigidity and strength of the photoelectric element 212 can be improved, and the module substrate 106 and the peripheral IC 214 can be warped or swelled. Further, as shown in FIG. 10, heat generated in the element body 218 can be radiated through the heat sink 238. Therefore, when the ambient temperature of the optical module 200 is relatively high, or when the element body 218 generates a relatively large amount of heat, the photoelectric element 212 can be effectively cooled.

  In the above embodiment, the mirror 240 is interposed between the optical fiber array 202 and the photoelectric element 212, but it is needless to say that the mirror 240 may not be interposed. In the case of this configuration, the distance between the optical fiber array 202 and the circuit surfaces 212d1 and 212e1 is preferably close to zero.

  Moreover, in the said embodiment, although the flexible film 216 of the photoelectric element 212 showed what consists of a light transmissive material, if a hole part is formed in the optical path of the optical signal in the flexible film 216, the flexible film 216 will be shown. Need not be a light-transmitting material.

  Furthermore, in the above embodiment, the wiring 212b is cut out in a predetermined direction right above the circuit surface 212d1 (212e1). For example, as shown in FIG. 11, the circuit surface 212d1 (212e1) Even if the layer of the wiring 212b is formed at a portion where transmission / reception of an optical signal is not hindered, no trouble is caused. That is, the shape of the layer of the wiring 212b can be changed as appropriate depending on the parallelism, strength, and the like required for the photoelectric element 212. In this case, the thickness of the flexible film 216 of the photoelectric element 212 can be made uniform, and the rigidity is increased by the wiring 212b, which is advantageous in manufacturing and the like.

  Further, in the above-described embodiment, the one using the flexible film 216 made of polyimide as the covering member is shown. However, the covering member may be another resin or the like, for example, a compound of an inorganic material such as ceramic and a resin. Of course, it may be.

  In the above embodiment, the photoelectric device 212 and the peripheral IC 214 are directly connected. However, for example, the photoelectric device 212 and the peripheral IC 214 may be connected via an interposer or the like. Of course, it can be appropriately changed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention, and is a schematic explanatory diagram of a mother board in which module substrates are connected using an optical module. It is an external appearance perspective view of an optical module. It is a longitudinal cross-sectional view of the optical module at the time of cut | disconnecting the optical module of FIG. 2 to AA direction, and is a figure which shows the relationship with a module board | substrate etc. It is a longitudinal cross-sectional view of the optical module of the state which separated the submodule and fiber connector at the time of cut | disconnecting the optical module of FIG. In FIG. 2, it is sectional drawing of the optical module which cut | disconnected the optical module in the BB cross section and looked at the cut surface from upper direction. It is sectional drawing of a photoelectric element, Comprising: (a) shows the thing before an assembly, (b) shows the thing after an assembly. It is sectional explanatory drawing of peripheral IC. It is a cross-sectional view of the optical module which shows a modification, Comprising: (a) shows what a photoelectric element makes a light emission part, (b) shows what a photoelectric element makes a light-receiving part. It is a longitudinal cross-sectional explanatory drawing of the photoelectric element which shows a modification. It is a cross-sectional view of the optical module which shows a modification. It is sectional explanatory drawing of the photoelectric element which shows a modification. It is schematic structure explanatory drawing of the conventional optical module, Comprising: (a) shows the state which the connection pin and the jack separated, (b) shows the state which the connection pin and the jack are contacting. It is a perspective view which shows schematic structure of the conventional optical module. It is sectional drawing which shows schematic structure of the conventional optical module. The schematic structure of the conventional optical module is shown, Comprising: (a) is a top view, (b) is sectional drawing.

Explanation of symbols

100 Motherboard 106 Module board 108 Module board 112 Signal wiring 114 Power supply wiring 200 Optical module 202 Optical fiber array 204 Submodule 206 Fiber connector 210 Optical module terminal 212 Photoelectric element 212b Wiring 212d VCSEL
212d1 Circuit surface 212e PIN-PD
212e1 Circuit surface 214 Peripheral IC
214b Wiring 216 Flexible film 218 Element body 220 Hole 222 Hole 224 Electrode 226 Electrode 228 Bump 230 External terminal 232 Interposer 234 Connector holder 234a Hole 236 Housing 236a Pin 238 Array fixing piece 240 Mirror

Claims (6)

An optical module provided on a substrate,
A semiconductor element electrically connected to the substrate;
A photoelectric element that is electrically connected to the semiconductor element and has a circuit surface that forms at least one of a light receiving unit that receives an optical signal and a light emitting unit that transmits an optical signal, and is optically connected to an optical fiber And comprising
The photoelectric element is arranged so that the circuit surface is on the upper side, and the body of the photoelectric element is formed by a covering member on which wiring for electrically connecting the circuit surface and the semiconductor element is formed. An optical module, which is covered from a circuit surface to a lower surface via a side surface and is electrically connected to the semiconductor element on the lower surface. A submodule in which the semiconductor element and the photoelectric element are arranged;
The optical module according to claim 1, further comprising: a fiber connector that is detachably provided on an upper portion of the submodule and to which the optical fiber is arranged. The fiber connector has a mirror part that is interposed between the optical fiber and the photoelectric element and reflects the optical signal,
The optical module according to claim 2, wherein the optical signal is configured to be substantially parallel to the substrate on the optical fiber side and to be substantially perpendicular to the substrate on the photoelectric element side.   4. The semiconductor device according to claim 1, wherein the semiconductor element is formed in a chip shape and is arranged substantially parallel to the photoelectric element, and forms at least one of a receiver and a driver of the photoelectric element. The optical module as described in any one. The semiconductor element is covered with a film in which wiring is formed, and the element body is covered from the upper part to the lower part via the side part,
The optical module according to claim 4, wherein the semiconductor element and the photoelectric element are stacked. An interposer in which an optical module terminal connected to the substrate is formed is connected to the lower part of the semiconductor element,
The optical module according to claim 5, wherein the interposer, the semiconductor element, and the photoelectric element are system-in-package.

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