JP2008292763A - Photoelectron circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectron circuit board allowing inspection of an optical element and an optical waveguide in a state that the optical element is mounted on the board. <P>SOLUTION: This photoelectron circuit board 1 has: first and second boards 10, 11 each having an optical circuit and an electronic circuit; and the optical waveguide 13 provided between the first and second boards 10, 11. An optical signal is leaked through an optical waveguide side opening 135 formed in a clad of the optical waveguide 13 and a board side opening 14 formed in the first board 10, and the photoelectron circuit board 1 can be inspected by observing leakage light 2a thereof by a CCD camera 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optoelectronic circuit board.

  Optical communication technology using light as an information transmission medium has become widespread. In such an optical communication technology, an optical integrated circuit in which an optical waveguide is disposed on a substrate has been proposed in order to transmit an optical signal obtained by modulating light with a signal indicating information (see, for example, Patent Document 1). ).

  This optical integrated circuit includes a mounting substrate, four surface emitting semiconductor laser elements disposed on one side of the mounting substrate, four photodiodes disposed on the other side of the mounting substrate, and a surface emitting semiconductor. An optical waveguide disposed on the laser element and the photodiode and having a reflection surface inclined at an angle of 45 degrees at a position facing the surface emitting semiconductor laser element and the photodiode. The optical waveguide has a structure in which four cores are covered with a clad having a refractive index smaller than that of the core, and a silicon substrate is formed on the upper surface.

The optical signals emitted from the four surface emitting semiconductor laser elements are reflected by one reflection surface of the optical waveguide, propagated while totally reflecting in the corresponding core, and reflected by the other reflection surface of the optical waveguide. It enters each of the four photodiodes.
JP 2004-302401 A

  An object of the present invention is to provide an optoelectronic circuit board capable of inspecting an optical element and an optical waveguide in a state where the optical element is mounted on the substrate.

  To achieve the above object, the present invention provides the following optoelectronic circuit board.

[1] A light emitting side opening that has an electronic circuit and allows an optical signal to pass from the first surface side to the second surface side, and passes the optical signal from the second surface side to the first surface side. A light receiving side opening formed thereon, a light emitting element mounted on the first surface side of the substrate and provided at a position facing the light emitting side opening to emit the optical signal, and the light receiving side opening A light receiving element for receiving the optical signal, a core and a cladding provided around the core, provided on the second surface side of the substrate, the light emitting side opening A first optical path conversion surface for converting an optical path of the optical signal passing from the first surface side to the second surface side, and the optical signal converted by the first optical path conversion surface is the light receiving side opening. Of the optical signal so as to pass from the second surface side to the first surface side. A second optical path conversion surface to be converted; and an inspection opening having the core width that is provided in the clad so as to expose the core and whose opening diameter is twice or more the wavelength of the optical signal. An optoelectronic circuit board comprising: an optical waveguide that outputs inspection light from the exposed core.

[2] The inspection opening of the optical waveguide is provided on the substrate side, and the substrate has an opening diameter equal to or larger than the opening diameter of the inspection opening at a position corresponding to the inspection opening. The optoelectronic circuit board according to the above [1], wherein a substrate-side inspection opening having the above is formed.

[3] Furthermore, another substrate is provided on the second surface side of the substrate via the optical waveguide, and the inspection opening of the optical waveguide is provided on the other substrate side, and the other substrate Is provided with a substrate side inspection opening having an opening diameter equal to or larger than the opening diameter of the inspection opening at a position corresponding to the inspection opening of the optical waveguide. Circuit board.

  According to the optoelectronic circuit board of the first aspect, the optical element and the optical waveguide can be inspected in a state where the optical element is mounted on the substrate.

  According to the optoelectronic circuit board of the second aspect, the inspection light can be observed from the first surface side on which the optical element is mounted.

  According to the optoelectronic circuit board of the third aspect, it is possible to increase the mounting density of electronic components and the like mounted on the board.

[First Embodiment]
1A and 1B show a schematic configuration of an optoelectronic circuit board according to a first embodiment of the present invention, in which FIG. 1A is a perspective view, FIG. 1B is a cross-sectional view along line AA in FIG. c) is a sectional view taken along line BB in (a), and (d) is a sectional view taken along line CC in (a).

  The optoelectronic circuit board 1 includes an optical circuit and an electronic circuit, and includes first and second substrates 10 and 11 having electronic circuits including various electronic components, power supply circuit components, and the like, and the first substrate 10. Of the first and second optical modules 12A and 12B mounted on the upper surface (first surface) side of the first and second substrates 10 and 11, and the first and second optical modules 12A. , 12B, and an optical waveguide 13 that optically connects between 12B.

  The first optical module 12A includes a light emitting element array 120 in which a plurality of light emitting elements 120a are arranged as an example, a drive circuit that drives the light emitting elements 120a, and the like. The second optical module 12B includes a light emitting element array 121 in which a plurality of light receiving elements 121a are arranged in a row, an amplifier that amplifies an output signal from the light receiving element 121a, and the like. The first and second optical modules 12A and 12B are packaged, and their detailed configurations will be described later.

(First substrate)
For example, the first substrate 10 is formed on a base material made of an insulating material such as a glass epoxy resin having a thickness of 0.5 mm, and an upper surface of the base material, and various electronic components, power circuit components, etc. An electrically connected conductive pattern.

  Further, the first substrate 10 has four light emitting side openings described later at positions facing the four light emitting elements 120a, and four light receiving side openings described later are formed at positions facing the four light receiving elements 121a. Is formed. The four light emitting side openings and the four light receiving side openings may be one common opening. Further, as shown in FIG. 1A, the first substrate 10 has a substrate side opening 14 by a through hole for taking out light for inspection. The opening diameter of the substrate side opening 14 only needs to be equal to or larger than the opening diameter of the optical waveguide side opening 135 described later, and is set to 5 × 5 mm in the present embodiment.

(Second substrate)
The second substrate 11 is formed on, for example, a base material made of an insulating material such as a glass epoxy resin having a thickness of 1 mm, and a lower surface of the base material. Various electronic components, power circuit components, and the like are electrically used. And a conductive pattern connected to the.

(Optical waveguide)
As shown in FIGS. 1B and 1C, the optical waveguide 13 has, for example, four cores 132 having an overall thickness of 0.2 mm and a rectangular cross section of 50 × 50 μm, for example. The clad 131 is formed around the core 132 and has a lower refractive index than the core 132.

  Further, as shown in FIG. 1D, the optical waveguide 13 has an optical waveguide side opening 135 at a position corresponding to the substrate side opening 14 provided on the first substrate 10 side. The optical waveguide side opening 135 is configured such that the core 132 of the optical waveguide 13 is exposed. The diameter of the opening is, for example, about the wavelength of the signal light (for example, 850 nm) to about twice the core width of the core 132. In this embodiment, it is 50 × 50 μm.

(Optical waveguide manufacturing method)
Next, an example of a method for manufacturing the optical waveguide 13 will be described. The optical waveguide 13 can be produced by, for example, a commonly used photolithography method or a method using RIE (reactive ion etching). In particular, it can be efficiently produced by a production process using a mold described in Japanese Patent Application Laid-Open No. 2004-29507 already proposed by the present applicant. The manufacturing process will be described below.

  First, a master on which convex portions corresponding to the four cores 132 are formed is produced using, for example, a photolithography method. Next, a curable resin having a viscosity of, for example, about 500 to 7000 mPa · s and having light transmittance in the ultraviolet region and the visible region, for example, a methylsiloxane group in the molecule, A layer of curable organopolysiloxane containing an ethylsiloxane group and a phenylsiloxane group is provided by coating or the like, and then cured to form a cured layer. Next, the hardened layer is peeled off from the master and a mold having a concave portion corresponding to the convex portion is produced.

  Next, a clad film substrate made of a resin excellent in adhesion to the mold, for example, an alicyclic acrylic resin film, an alicyclic olefin resin film, a cellulose triacetate film, a fluororesin film, or the like is adhered to the mold. Let Next, the concave portion of the mold is filled with, for example, an ultraviolet curable or thermosetting monomer, an oligomer or a mixture of a monomer and an oligomer, an epoxy type, a polyimide type, an acrylic type ultraviolet curable resin, or the like. . Next, the curable resin in the recess is cured to form the core 132, and then the mold is peeled off. As a result, four cores 132 are left on the clad film substrate.

  Next, the clad 131 is provided so as to cover the core 132 on the side of the clad film substrate on which the core 132 is formed. At this time, an optical waveguide side opening 135 where the clad 131 is not formed is provided at a position corresponding to the substrate side opening 14 of the first substrate 10 so that the core 132 is exposed. Examples of the clad 131 include a film, a layer obtained by applying and curing a curable resin for clad, and a polymer film obtained by applying a solvent solution of a polymer material and drying.

  Finally, the surface where the core 132 of the optical waveguide is exposed is cut at a predetermined angle by a dicer to form an optical path conversion surface. Further, by cutting with a dicer parallel to the core 132, the optical waveguide 13 having the clad film base material and the clad layer as the clad 131 is completed. Thereafter, an inspection opening (optical waveguide side opening 135) according to the present invention is formed by a method such as laser processing.

(Optical module)
FIG. 2 shows an outline of the optoelectronic circuit board according to the first embodiment of the present invention, and FIG. 2 (a) is a cross-sectional view taken along the line CC of FIG. 1 (a).

  The first optical module 12A includes a control unit 127A mounted on the upper surface of the substrate 129, and a sealing resin 128A such as an epoxy resin that seals the terminal 124, the wire 126, and the control unit 127A.

  As shown in FIG. 2A, the light emitting element array 120 of the first optical module 12A is mounted on the lower surface of the substrate 129, and is connected to the control unit 127A provided on the substrate 129 via the wires 122 and the pads 123. Electrically connected. The wires 122 and the light emitting element array 120 are sealed with an optical resin material 128B capable of matching the refractive index between the optical elements (120a, 121a) and the optical waveguide 13.

  As the light emitting element 120a of the light emitting element array 120, a plurality of light emitting elements (surface optical elements) such as a surface light emitting diode and a surface laser can be used. In the present embodiment, a VCSEL (surface emitting laser) is used as the light emitting element 120a.

  In this surface emitting laser, for example, an n-type upper reflector layer, an active layer, a current confinement layer, a p-type lower reflector layer, a p-type contact layer, and a p-type electrode are formed on an n-type GaAs substrate. An n-type electrode is formed on the front side of the substrate.

  The control unit 127A has a drive circuit that drives the four light emitting elements 120a, and is electrically connected to the terminal 110 via the wire 126, the terminal 124, and the solder ball 125, and is protected by the sealing resin 128. Yes.

(Second optical module)
The second optical module 12B includes a control unit 127A mounted on the upper surface of the substrate 129, and a sealing resin 128A such as an epoxy resin that seals the terminal 124, the wire 126, and the control unit 127A.

  As shown in FIG. 2A, the light receiving element array 121 of the second optical module 12B is mounted on the lower surface of the substrate 129, and is connected to the control unit 127A provided on the substrate 129 via the wire 122 and the pad 123. Electrically connected. The wire 122 and the light receiving element array 121 are sealed with an optical resin material 128B capable of matching the refractive index between the optical element and the waveguide.

  The control unit 127A includes an amplifier circuit that amplifies the electric signals output from the four light receiving elements 121a, and is electrically connected to the terminal 110 via the wire 126, the terminal 124, and the solder ball 125, and includes a sealing resin. 128 is protected.

  As the light receiving element 121a of the light receiving element array 121, for example, a planar optical element such as a planar photodiode can be used. In the present embodiment, a GaAs PIN photodiode excellent in high-speed response is used as the light receiving element. The PIN photodiode includes, for example, a P-layer, an I-layer, and an N-layer that are PIN-bonded on a GaAs substrate, a p-type electrode connected to the P-layer, and an n-type electrode formed on the N-layer. ing.

(Operation of the first embodiment)
The operation of the optoelectronic circuit board according to the first embodiment of the present invention will be described below with reference to FIGS.

(1) Transmission / Reception of Optical Signal Here, as an example, a case where an image signal is transmitted from the first optical module 12A to the second optical module 12B will be described. The drive circuit of the control unit 127A of the first optical module 12A transmits a drive signal to the light emitting element 120a of the light emitting element array 120 based on the image signal. The light emitting element 120a transmits the optical signal 2 toward the optical path conversion surface 133A of the optical waveguide 3 through the light emission side opening 100A based on the drive signal. At this time, the voltage of the drive signal is applied between the p-type electrode and the n-type electrode of the light emitting element 120a, and for example, laser light having a wavelength of 850 nm is output as the optical signal 2 from the light emitting region of the light emitting layer.

  The optical path conversion surface 133A converts the optical path of the optical signal 2 transmitted from the light emitting element 120a and propagates the optical signal 2 to the core 132 of the optical waveguide 13. At this time, the leakage light 2a is output from the optical waveguide side opening 135 to the first substrate 10 side, but the amount of the leakage light 2a is small, so that the transmission of the image signal is not affected. The optical signal 2 propagated to the core 132 has its optical path converted by the optical path conversion surface 133B, passes through the light receiving side opening 101B, and is received by the light receiving element array 121 of the second optical module 12B. The light receiving element 121a converts the received optical signal 2 into an electrical signal and outputs it to the control unit 127B.

  The amplifier of the control unit 127B amplifies the converted electric signal, and the signal processing circuit processes the signal from the amplifier to generate an image signal, and performs predetermined electrons on the first or second substrate 10 or 11. Output to parts.

(2) Inspection of Optoelectronic Circuit Board First, the optical signal 2 is output from the light emitting element array 120 of the first optical module 12A. The output optical signal 2 passes through the light emission side opening 100 </ b> A, is converted in optical path by the optical path conversion surface 133 </ b> A, and propagates through the core 132 of the optical waveguide 13.

  As for the optical signal 2 propagated to the core 132, the leaked light 2 a is emitted from the exposed core 132 of the optical waveguide side opening 135. The leakage light 2 a from the optical waveguide side opening 135 is observed by the CCD camera 3. Note that the method of observing the leakage light 2a is not limited to the CCD camera 3, and other methods may be used. For example, the leakage light 2a may be derived from the optical waveguide side opening 135 by an optical fiber and detected by a photodiode or the like.

  When the four leakage lights 2a can be observed with an appropriate amount of light by the CCD camera 3, it can be seen that the first optical module 12A side is operating normally. After completion of the inspection, the optical waveguide side opening 135 need not be sealed, but may be sealed.

  When the number of leaked light 2a that can be observed with an appropriate light amount by the CCD camera 3 is three or less, the corresponding light emitting element 120a of the first optical module 12A is malfunctioning or the light guide 13 on the light emitting element array 120 side of the optical waveguide 13 It can be seen that dust or the like adheres to the optical path conversion surface 133A side and the optical path is defective.

[Second Embodiment]
FIG. 3 shows a schematic configuration of the optoelectronic circuit board according to the second embodiment of the present invention, and is a cross-sectional view corresponding to a cross section taken along the line CC in FIG.

  In the first embodiment, the optical waveguide side opening 135 and the substrate side opening 14 are formed on the first substrate 10 side. However, in the present embodiment, the optical waveguide side opening 135 and the substrate are provided on the second substrate 11 side. A side opening 14 is formed, and the others are configured in the same manner as in the first embodiment.

  The first substrate 10 has a light emitting side opening and a light receiving side opening at positions facing the light emitting element 120a and the light receiving element 121a, respectively, but no inspection opening is formed.

  The optical waveguide 13 has an optical waveguide side opening 135 in the middle of the optical transmission path and immediately below the four cores 132.

  The second substrate 11 has a substrate side opening 14 having an opening diameter of 5 × 5 mm, for example, at a position corresponding to the optical waveguide side opening 135.

  Also in the second embodiment, the light emitting element array 120 is driven to output the optical signal 2, and the leakage light 2 a from the optical waveguide side opening 135 of the optical waveguide 13 is emitted from the second substrate 11 by the CCD camera 3. By observing from the back side, it is possible to inspect whether there is an abnormality in the light emitting element 120a or the like.

[Third Embodiment]
FIG. 4 shows a schematic configuration of the optoelectronic circuit board according to the third embodiment of the present invention, and is a cross-sectional view corresponding to a cross section taken along the line CC of FIG.

  Although the second substrate 11 is used in the second embodiment, the present embodiment has a configuration in which the second substrate 11 is not used. Therefore, the sealing agent 200 that seals the optical waveguide 13 used in the second embodiment is not provided. Others are configured in the same manner as in the second embodiment.

  Also in the third embodiment, the light emitting element array 120 is driven to output the optical signal 2, and the leakage light 2 a from the optical waveguide side opening 135 of the optical waveguide 13 is emitted from the first substrate 10 by the CCD camera 3. By observing from the back side, it is possible to inspect whether there is an abnormality in the light emitting element 120a or the like.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from or changing the technical idea of the present invention.

1A and 1B show a schematic configuration of an optoelectronic circuit board according to a first embodiment of the present invention, in which FIG. 1A is a perspective view, FIG. 1B is a cross-sectional view along line AA in FIG. c) is a sectional view taken along line BB in (a), and (d) is a sectional view taken along line CC in (a). Fig.2 (a) is the DD sectional view taken on the line of Fig.1 (a). FIG. 3 is a cross-sectional view corresponding to the cross section taken along the line CC of FIG. 1A, showing a schematic configuration of the optoelectronic circuit board according to the second embodiment of the present invention. FIG. 4 is a cross-sectional view corresponding to the cross section taken along the line CC of FIG. 1A, showing a schematic configuration of the optoelectronic circuit board according to the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optoelectronic circuit board, 2 ... Optical signal, 2a ... Leakage light, 3 ... CCD camera, 10 ... 1st board | substrate, 11 ... 2nd board | substrate, 12A ... 1st optical module, 12B ... 2nd optical module , 13 ... optical waveguide, 14 ... substrate side opening, 100A ... light emission side opening, 101B ... light reception side opening, 110 ... terminal, 120 ... light emitting element array, 120a ... light emitting element, 121 ... light receiving element array, 121a ... light receiving element, DESCRIPTION OF SYMBOLS 122 ... Wire, 123 ... Pad, 124 ... Terminal, 125 ... Solder ball, 126 ... Wire, 127A ... Control part, 127B ... Control part, 128A ... Sealing resin, 128B ... Optical resin material, 129 ... Substrate, 131 ... Cladding 132: Core 133A: Optical path conversion surface 133B: Optical path conversion surface 135: Optical waveguide side opening

Claims (3)

A light emitting side opening that has an electronic circuit and passes an optical signal from the first surface side to the second surface side, and a light receiving side that passes the optical signal from the second surface side to the first surface side A substrate with an opening formed thereon;
A light emitting element mounted on the first surface side of the substrate and provided at a position facing the light emitting side opening to emit the optical signal, and a light emitting element provided at a position facing the light receiving side opening. A light receiving element for receiving light;
The light comprising a core and a clad provided around the core, provided on the second surface side of the substrate, and passing through the light emitting side opening from the first surface side to the second surface side A first optical path conversion surface for converting an optical path of the signal, and the optical signal converted by the first optical path conversion surface passes through the light receiving side opening from the second surface side to the first surface side. A second optical path conversion surface for converting the optical path of the optical signal, and an inspection opening having the core width that is provided in the clad so as to expose the core and whose opening diameter is twice the wavelength of the optical signal. An optoelectronic circuit board comprising: an optical waveguide that outputs inspection light from the core exposed in the inspection opening; The inspection opening of the optical waveguide is provided on the substrate side,
2. The optoelectronic circuit board according to claim 1, wherein a substrate-side inspection opening having an opening diameter equal to or larger than the opening diameter of the inspection opening is formed at a position corresponding to the inspection opening. . Furthermore, another substrate is provided on the second surface side of the substrate via the optical waveguide,
The inspection opening of the optical waveguide is provided on the other substrate side,
2. The substrate-side inspection opening having an opening diameter equal to or larger than the opening diameter of the inspection opening at a position corresponding to the inspection opening of the optical waveguide. The optoelectronic circuit board described.

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