JP2009212338A - Photoelectric conversion module and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a VCSEL module 1 can suppress light reflection on a surface of a glass substrate 20 by an anti-reflection film while evading a wiring pattern from being peeled off due to the anti-reflection film formed between the glass substrate 20 and the wiring pattern. <P>SOLUTION: On one face side of the glass substrate 20 on which the wiring pattern is formed in a non-opposite area to a light-receiving part of a VCCEL 10 out of the whole area of the one face, the wiring pattern is formed so as to be directly fixed on a pure surface of the glass substrate 20, and on the one face side, an anti-reflection film 21 is formed in an area opposed at least to the light-receiving part of the VCSEL 10 out of a wiring pattern non-formation area of the glass substrate 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion module including an electronic component including a light emitting unit or a light receiving unit, and a light transmission plate on which the electronic component is mounted, and a photoelectric conversion module manufacturing method for manufacturing the photoelectric conversion module.

  Conventionally, a VCSEL module manufacturing method described in Patent Document 1 is known as this type of photoelectric conversion module manufacturing method. In this VCSEL module manufacturing method, a vertical cavity surface emitting laser (hereinafter referred to as “VCSEL”) bare chip as an electronic component is mounted on a transparent substrate to obtain a VCSEL module as a photoelectric conversion module. A wiring pattern is formed on one surface of the transparent substrate. Further, a bonding layer made of a gold-tin alloy is formed on the surface of the electrode pad of this wiring pattern. A VCSEL bare chip is placed on the bonding layer of such a transparent substrate, and the bonding layer and the electrode of the VCSEL bare chip are brought into contact with each other. Thereafter, a laser beam for melting the bonding layer is emitted toward the surface of the transparent substrate opposite to the wiring pattern forming surface. Then, the emitted laser light is transmitted through the transparent substrate of the wiring board, and the laser beam after transmission is applied to the back surface of the electrode pad of the wiring pattern, thereby melting the bonding layer on the surface of the electrode pad. The VCSEL bare chip is mounted on the transparent substrate by bonding the electrode pad and the VCSEL bare chip electrode by this melting. In such a VCSEL module manufacturing method, it is possible to heat and melt only the bonding layer by laser light irradiation without heating the VCSEL bare chip in a furnace. Even in a VCSEL module including another electronic component in addition to the VCSEL bare chip, the VCSEL bare chip can be mounted on the transparent substrate without heating as follows. That is, first, a transparent substrate on which another electronic component is placed is heated in a furnace to join the electronic component and the transparent substrate by melting the solder. Next, after placing the VCSEL bare chip on the transparent substrate, only the bonding layer is heated by the laser light irradiation as described above. As described above, by mounting the VCSEL bare chip on the transparent substrate, it is possible to avoid the deterioration of the VCSEL bare chip due to heating in the furnace.

  In addition, as a photoelectric conversion module, there is a module equipped with a CCD (Charge Coupled Device) bare chip or a CMOS (Complementary Metal Oxide Semiconductor) bare chip equipped with a light receiving unit, in addition to a module equipped with a VCSEL bare chip having a light emitting unit. In these photoelectric conversion modules, a transparent substrate is disposed to face the light receiving portion of the CCD bare chip or the CMOS bare chip so as to transmit the light before entering the light receiving portion of the CCD bare chip or the CMOS bare chip.

In addition, in a photoelectric conversion module such as a VCSEL module, in order to suppress light reflection on the surface of the transparent substrate, an antireflection film having a multilayer structure made of a SiO ₂ film or a SiO film is formed on the surface of the transparent substrate. It is common to do.

  In recent photoelectric conversion modules, modules that emit light simultaneously from a plurality of light emitting units and modules that simultaneously receive light from a plurality of light receiving units are on the market. In such a photoelectric conversion module, it is required to form wiring patterns on a transparent substrate at a fine pitch in order to reduce the size of the module.

Japanese Patent Laid-Open No. 2007-19103

The inventors of the present invention performed an experiment for manufacturing a wiring board for a VCSEL module as follows. That is, on both sides of a glass substrate made of barium borosilicate glass, to form a SiO film of about 100 [nm], the anti-reflection film having a layered structure of the SiO ₂ film of about 100 [nm], a glass substrate And a transparent substrate having an antireflection film was prepared. By forming antireflection films on both surfaces of the glass substrate, it is possible to suppress reflection of laser light on the light incident side surface and the light emission side surface of the glass substrate. After forming an aluminum layer made of an aluminum alloy for a wiring pattern on one surface of the transparent substrate, the aluminum layer was patterned at a fine pitch of about 30 to 50 [μm] by a photolithography method or the like. Then, a nickel plating layer and a gold plating layer were sequentially laminated on the surface of the patterned aluminum layer to obtain a three-layer wiring pattern. Then, a part of the aluminum layer patterned with a fine pitch peeled off from the surface of the transparent substrate during the nickel plating process or the gold plating process. In addition, even in a place where peeling did not occur during the plating process, there was a case where peeling occurred due to an impact or pressure applied in a subsequent process.

  In addition, since the antireflection film was an extremely thin film of about 200 [nm], the fine pitch aluminum layer was peeled off from the antireflection film, or the aluminum layer forming portion in the antireflection film was an aluminum layer with a fine pitch. It was not possible to specify which of the two cases fell off.

  Next, the inventors tried to manufacture a wiring board for a VCSEL module as follows. That is, the antireflection film is formed on both surfaces of the glass substrate. First, the antireflection film is formed only on one surface. On the other side, an aluminum layer patterned to a fine pitch is formed on the solid surface of the glass substrate in the same manner as in the previous experiment, and then a nickel plating layer and a gold plating are formed on the aluminum layer. A wiring pattern having a three-layer structure was obtained by laminating the layers. Next, an antireflection film was formed on the entire other surface from the upper side of the wiring pattern. An antireflection film may be formed only in the area where the solid surface of the substrate is exposed without the wiring pattern, but an antireflection film is also formed on the wiring pattern to simplify the operation. . Then, the aluminum layer was not peeled off from the solid surface of the glass substrate in the plating process at the time of forming the wiring pattern and the subsequent processes. Moreover, as an aluminum layer, instead of an aluminum alloy, an aluminum layer made of pure aluminum was formed in the same manner. In this case, however, the aluminum layer was not peeled off from the solid surface of the glass substrate.

  From the above experiment, it was revealed that the antireflection film interposed between the glass substrate and the aluminum layer patterned in a fine pitch makes it easy to peel off the aluminum layer.

  The present invention has been made in view of the above background, and an object thereof is to provide the following wiring board. That is, light reflection on the surface of the light transmission plate is prevented by the antireflection film while preventing the wiring pattern from peeling off by interposing the antireflection film between the substrate having light transmittance such as a glass substrate and the wiring pattern. It is a photoelectric conversion module which can suppress. Moreover, it is providing the photoelectric conversion module manufacturing method which manufactures this photoelectric conversion module.

In order to achieve the above object, an invention according to claim 1 is a light-emitting unit that emits light by converting an electrical signal into light, or an electronic component that has a light-receiving unit that converts received light into an electrical signal; A substrate made of a material having an antireflection film made of a light-transmitting material formed on both sides of the substrate and transmitting the light emitted from the light emitting part to itself, or the light receiving part A light transmitting plate disposed opposite to the electronic component so as to transmit light before entering the light, and a light emitting portion or a light receiving portion of the entire region on one surface of the light transmitting plate And a wiring pattern formed in a non-opposing region, and the electronic component has a driving electrode for supplying a driving voltage to the light emitting part or the light receiving part at a position facing the wiring pattern. Opposing wiring pattern and driving In the photoelectric conversion module in which the electrode is bonded with a conductive bonding material, the wiring pattern is directly fixed to the solid surface of the substrate on the one surface side of the light transmission plate, and the On one surface side, the antireflection film is formed in at least a region facing the light emitting portion or the light receiving portion in the wiring pattern non-forming region of the substrate.
According to a second aspect of the present invention, in the photoelectric conversion module of the first aspect, a glass substrate made of barium borosilicate glass is used as the substrate, and the wiring pattern is directly fixed to a solid surface of the substrate. The portion to be formed is made of aluminum or an aluminum alloy mainly composed of aluminum.
According to a third aspect of the present invention, in the photoelectric conversion module according to the second aspect, the wiring pattern includes an aluminum layer made of aluminum or an aluminum alloy that is directly fixed to a solid surface of the substrate, and a surface of the aluminum layer. A multilayer structure having a nickel layer made of nickel and a gold layer made of gold laminated on the surface of the nickel layer is formed.
According to a fourth aspect of the present invention, there is provided the photoelectric conversion module according to the third aspect, wherein the antireflection film includes a SiO film made of SiO and a SiO ₂ film made of SiO ₂ formed on the surface thereof. A structure is formed.
Further, the invention of claim 5 is a light emitting portion that emits light by converting an electric signal into light, or an electronic component that has a light receiving portion that converts received light into an electric signal, and a substrate made of a material having optical transparency, And an anti-reflection film made of a light-transmitting material formed on both surfaces of the substrate, respectively, and allows light emitted from the light emitting part to pass through itself or light before entering the light receiving part Of the light transmitting plate disposed opposite to the electronic component and the entire region on one surface of the light transmitting plate in a region not facing the light emitting portion or the light receiving portion. Wirings formed in such a manner that the electronic component has a driving electrode for supplying a driving voltage to the light emitting part or the light receiving part at a position facing the wiring pattern, and is opposed to each other. Conductive bonding of pattern and drive electrode In the photoelectric conversion module manufacturing method for manufacturing the photoelectric conversion module bonded in the step, the step of forming the antireflection film on the solid substrate surface on the surface on which the wiring pattern is not formed among the both surfaces of the substrate; A pattern forming step of directly bonding the wiring pattern to a solid substrate surface on the surface on which the wiring pattern is formed, and a wiring pattern non-forming region on the surface of the substrate on which the wiring pattern is formed 5. The photoelectric conversion module according to claim 1, wherein at least a step of forming the antireflection film in a region facing the light emitting portion or the light receiving portion of the solid substrate surface existing in The photoelectric conversion module is obtained.
The invention according to claim 6 is the method for manufacturing a photoelectric conversion module according to claim 5, wherein a glass substrate made of barium borosilicate glass is used as the substrate, and in the pattern forming step, the surface of the glass substrate is a solid surface. After patterning an aluminum layer formed of aluminum by sputtering or an aluminum alloy containing aluminum as a main component, a nickel plating layer by nickel plating and a gold plating by gold plating on the surface of the patterned aluminum layer The photoelectric conversion module according to claim 3 is manufactured by sequentially laminating layers and forming the wiring pattern having a multilayer structure.

  In these inventions, since the wiring pattern is linearly fixed to the solid surface of the substrate of the light transmission plate, the peeling off of the wiring pattern due to the interposition of the antireflection film between the substrate and the wiring pattern is avoided. be able to. In addition, the light emitted from the light emitting part or the light before entering the light receiving part by the antireflection film formed in the region facing the light emitting part or the light receiving part of the electronic component in the wiring pattern non-forming area of the substrate, The reflection on the surface of the light transmission plate can also be suppressed.

  In particular, in the invention of claim 2, as clarified in the experiment described above by the present inventors, the fixing portion with the surface of the glass substrate made of barium borosilicate glass is aluminum or A fine pitch wiring pattern made of an aluminum alloy can be satisfactorily fixed.

  In particular, in the invention of claim 3, it is possible to exhibit a good adhesion force to both the gold layer and the aluminum layer which are difficult to exert a good adhesion force to the aluminum layer. By interposing the nickel layer between the aluminum layer and the gold layer, the gold layer can be fixed on the aluminum layer. Furthermore, the oxidation of the aluminum layer and the nickel layer can be suppressed by forming the gold layer that is difficult to oxidize on the aluminum layer and the nickel layer that are easily oxidized.

In particular, in the invention of claim 4, light reflection on the substrate surface can be suppressed by the antireflection film having a two-layer structure of the SiO film and the SiO ₂ film.

  In particular, in the invention of claim 5, it is possible to suppress the occurrence of poor conduction between the light emitting element and the power supply circuit due to damage to the wiring pattern caused by partial peeling of the wiring pattern from the substrate surface on the wiring board. .

  In particular, in the invention of claim 6, the aluminum layer is formed on the solid surface of the glass substrate by a sputtering method, so that the aluminum layer on the glass substrate is formed as compared with the case of forming the aluminum layer by a vapor deposition method. The fixing force can be increased. In addition, a gold plating layer that is difficult to exhibit good adhesion to the aluminum layer and a nickel plating layer that can exhibit good adhesion to both the aluminum layer and the aluminum plating layer The gold plating layer can be fixed on the aluminum layer. Furthermore, the oxidation of the aluminum layer and the nickel plating layer can be suppressed by forming the gold plating layer that is difficult to oxidize on the aluminum layer and the nickel plating layer that are easily oxidized.

Hereinafter, an embodiment of a VCSEL module as a photoelectric conversion module to which the present invention is applied and a VCSEL module manufacturing method will be described.
FIG. 1 is a sectional view showing an example of a VCSEL module according to the embodiment. The VCSEL module 1 includes a VCSEL bare chip 10 as an electronic component having a light emitting unit that emits light based on an electrical signal, and a wiring board bonded to the light emitting unit side of the VCSEL bare chip 10.

  The VCSEL bare chip 10 emits laser light having a predetermined wavelength from 40 light emitting units (not shown). In this embodiment, the VCSEL module 1 having the VCSEL bare chip 10 that outputs a laser beam having a wavelength of 780 nm with a structure in which compound semiconductors are stacked is described as the light emitting element. However, the light emitting element is limited to the VCSEL bare chip 10. The present invention can also be applied to photoelectric conversion modules having other light emitting elements.

  The wiring board includes a glass substrate 20 capable of transmitting laser light emitted from the VCSEL bare chip 10 and an antireflection film 21 capable of transmitting laser light respectively formed on both surfaces thereof. A light transmitting plate is provided. Moreover, it also has a wiring pattern 30 formed on one surface of the glass substrate 20. The wiring pattern 30 has a wiring portion extending in the surface direction of the glass substrate 20 and an electrode pad provided in the longitudinal direction end portion or in the middle of the wiring portion. The wiring pattern 30 is shown without distinction between wiring parts and electrode pads. In addition, as electrode pads of the wiring pattern 30, bonding is performed to an element bonding electrode pad that is bonded to a drive electrode (not shown) of the VCSEL bare chip 10, and a main wiring board that will be described later, which is a different wiring board from the wiring board of the VCSEL module. An inter-substrate bonding electrode pad, a solder supply electrode pad to be described later, and the like are provided.

  In the vicinity of the outer edge of the VCSEL bare chip 10 in the surface direction, 40 drive electrodes (not shown) individually connected to the 40 light emitting units described above are provided. These drive electrodes and 40 element bonding electrodes (not shown) formed on the wiring pattern 30 of the wiring board are bonded via a bonding layer 40 made of solder, which is a heat-meltable conductive material. A resin 50 is fixed between the outer edge of the VCSEL bare chip 10 and the surface of the wiring board so as to surround the outer edge of the VCSEL element 10. With this resin 50, the gap between the VCSEL bare chip 10 and the wiring board is sealed from the outside to form a sealed space 70. In this sealed space 70, dry gas such as dry nitrogen gas is sealed so as not to deteriorate the VCSEL bare chip 10. Further, bonding layers 60 made of solder are respectively formed on the surfaces of 40 electrode pads for bonding between substrates (not shown) formed in the vicinity of the ends in the longitudinal direction of the wiring pattern 30 on the glass substrate 20. .

  The glass substrate 20 is made of D263 which is barium borosilicate glass. A barium borosilicate glass such as 7059 or AN may be used.

As the above-described antireflection film 21, a two-layer structure having an SiO layer with a thickness of about 100 [nm] and an SiO ₂ layer with a thickness of about 100 [nm] formed on the surface thereof is adopted. ing. The antireflection film 21 is formed on both surfaces of the glass substrate 20. Of the both surfaces, the wiring pattern forming surface is formed on the solid surface of the glass substrate 20 and then the glass substrate 20. An antireflection film 21 is formed on a solid surface in the wiring pattern non-formation region.

  As the wiring pattern 30, one having a single layer structure made of only an aluminum layer using aluminum or an aluminum alloy, or one having a layer made of a metal material formed on one or more layers on the aluminum layer can be applied. As an aluminum alloy, an aluminum silicon copper containing aluminum, silicon and copper as main components can be exemplified. The aluminum alloy used in the experiment described above is this aluminum silicon copper.

  The bonding layer 40 formed on the element bonding electrode pad of the wiring pattern 30 and the bonding layer 60 formed on the inter-substrate bonding electrode pad are used to melt the bonding layer in the bonding process described later. It consists of a heat-meltable conductive material that melts in response to the laser light used (for example, YAG laser light with a wavelength of 1064 nm). Examples of the heat-meltable conductive material include solder, a metal material having an electric resistance equal to or lower than that of solder, and a metal material having a crystal structure other than the face-centered cubic lattice structure. More specific examples include solder, molybdenum, zinc, cobalt, tungsten, tin, cadmium and the like. Examples of the solder include Sn—Ag—Cu solder having a relatively low melting temperature and Sn—Bi solder.

  As the resin 50 for forming the sealed space 70, for example, an epoxy resin can be used. More specifically, a black one-pack epoxy resin (product number: XNR5163NF, XNR5163) manufactured by Nagase ChemteX Corporation is applied and cured under curing conditions (for example, 100 ° C / 1 hour + 150 ° C / 1 hour). Let it be used.

  FIG. 2 is a plan view showing a configuration example of the VCSEL bare chip 10. The VCSEL bare chip 10 is a plate-like element having a side length of, for example, about 1 [mm]. The VCSEL bare chip 10 includes a light emitting unit 11 including 40 light emitting units 15 at the center thereof. The in-element wiring 13 extends from each light emitting unit 15 in the plate surface direction. The drive electrode 12 described above is provided at the end of each of the plurality of intra-element wires 13. A common ground electrode (not shown) connected to each light emitting unit 15 is provided on the back side (not shown) of the VCSEL bare chip 10. In a state where the earth electrode is connected to the earth, a driving voltage is individually applied to each driving electrode 12, whereby laser light is individually emitted from each light emitting unit 15.

  FIG. 3 is a plan view showing a configuration example of the wiring board of the VCSEL module 1. In the figure, members indicated by reference numerals 31, 32, and 33 are electrode pads or wiring portions that constitute a part of the wiring pattern 30 described above. The region indicated by reference numeral 20a indicates an element facing region, which is a region where the glass substrate 20 faces the VCSEL when a VCSEL (not shown) is mounted on the surface of the glass substrate 20. As illustrated, the glass substrate 20 has a larger planar area than the VCSEL so that the outer edge portion in the surface direction of the glass substrate 20 is located outside the VCSEL. Forty element bonding electrode pads 31 are formed on the outer edge portion of the glass substrate 20 in the element facing region 20a in the surface direction. As can be seen from FIG. 4 showing the VCSEL module in which the VCSEL bare chip 10 is mounted on the glass substrate 20, the 40 drive electrodes 12 of the VCSEL bare chip 10 are individually provided directly under the 40 element bonding electrode pads 31. The VCSEL bare chip 10 is mounted on the glass substrate 20 in the positioned state. A wiring portion 33 extends from the 40 element bonding electrode pads 31 in the wiring substrate made of the glass substrate 20 or the like toward the outer edge portion in the surface direction of the glass substrate 20, and ends of the respective wiring portions 33. An inter-substrate bonding electrode pad 32 is formed.

  FIG. 5 is a cross-sectional view showing an electronic circuit board in which the VCSEL module 1 which is an electronic circuit board is mounted on a main board 90 different from this. A driver IC (not shown) for individually driving 40 light emitting units (not shown) of the VCSEL bare chip 10 mounted on the VCSEL module 1 is mounted in a region (not shown) of the main substrate 90. In addition, an opening 90 a for receiving the VCSEL bare chip 10 of the VCSEL module 1 is formed in the main substrate 90. The VCSEL module 1 is mounted on the main board 90 in such a posture that the VCSEL bare chip 10 is inserted into the opening 90a of the main board 90 and the outer edge of the VCSEL module 1 is hooked around the opening 90a of the main board 90. Has been.

  In the main substrate 90, 40 module bonding electrode pads (not shown) are formed around the opening 90a. On the other hand, the VCSEL module 1 has 40 inter-substrate bonding electrode pads that are part of the wiring pattern 30 and formed on the outer edge of the wiring substrate of the VCSEL module 1 as described above. These 40 inter-substrate bonding electrode pads are bonded to the 40 module bonding electrode pads around the opening 90a of the main substrate 90 through the bonding layer 60, respectively. In the main substrate 90, the 40 module bonding electrode pads are individually connected to the output terminals of the driver ICs described above. As a result, drive voltages individually output from the 40 output terminals of the driver IC are supplied to the 40 of the VCSEL bare chip 10 via the module bonding electrode pad of the main substrate 90 and the wiring pattern 30 of the VCSEL module 1. The light emitting units (15) are individually applied. A ground electrode 14 is formed on the back surface of the VCSEL bare chip 10 and is connected to the ground electrode 91 of the main substrate 90 via a conductive adhesive 93.

  In the VCSEL module manufacturing method according to the present embodiment, a wiring board manufacturing process for manufacturing a wiring board including the glass substrate 20, the antireflection film 21, the wiring pattern 30, the bonding layer 40, and the bonding layer 60 is obtained. And a mounting step of mounting the VCSEL bare chip 10 on the wiring board. Further, in the wiring board manufacturing process, a first antireflection film forming process for forming the antireflection film 21 on the wiring pattern non-forming surface of the glass substrate 20, a first cleaning process, a pattern forming process, and a bonding layer forming process. Then, a second cleaning process and a second antireflection film forming process for forming the antireflection film 21 on the solid surface of the wiring pattern non-formation region on the wiring pattern formation surface of the glass substrate 20 are performed.

In the first antireflection film forming step, as shown in FIG. 6, an antireflection film 21 is formed on the entire surface of the glass substrate 20 where no wiring pattern is formed. More specifically, first, after forming a thickness of 100 [nm] by depositing a SiO layer of SiO on the solid surface of the glass substrate 20, by depositing a SiO ₂ layer of SiO ₂ on top of the SiO layer It is formed with a thickness of 100 [nm]. Thus, the antireflection film 21 having a thickness of 200 [nm] is formed on the entire surface where the wiring pattern is not formed.

  If the surface of the glass substrate 20 is dirty, it becomes difficult to stably fix the film there. Therefore, in the first cleaning step, the adhesion of the film to the substrate is improved by cleaning the wiring pattern forming surface of the glass substrate 20. Examples of the cleaning method include a cleaning method by blowing high-pressure air, a method of drying the substrate cleaning surface after washing away dirt with a cleaning liquid, and a cleaning method by blowing carbon dioxide. By removing the fine foreign matter adhering to the wiring pattern forming surface of the glass substrate 20 by such a first cleaning step, the fine foreign matter between the solid surface of the glass substrate 20 and the aluminum layer 30a is removed. It is possible to avoid a decrease in the fixing force of the aluminum layer 30a due to the interposition of.

In the pattern forming step, as shown in FIG. 7, a wiring pattern 30 that is fixed to a solid surface of the glass substrate 20 and protrudes with a predetermined thickness from the surface is formed on the wiring pattern forming surface of the glass substrate 20. It is formed on the outer edge in the surface direction. The wiring pattern 30 has a three-layer structure of an aluminum layer made of aluminum fixed on a solid surface of the glass substrate 20, a nickel plating layer laminated on the surface, and a gold plating layer laminated on the surface. Become. A specific process for forming the wiring pattern 30 having such a three-layer structure is as follows. That is, first, an aluminum layer is formed on the entire surface of the wiring pattern forming surface of the glass substrate 20 by a sputtering method, and then the aluminum layer is patterned to a fine pitch by an etching process employing a photolithography method. Next, a nickel plating layer and a gold plating layer are sequentially laminated on the surface and side surfaces of the patterned aluminum layer. The conditions for forming the aluminum layer by sputtering are as follows.
(1) Sputtering apparatus:
-Manufacturer name: Shinko Seiki Co., Ltd.-Model: SRV4311
・ Performance: 3 source magnetron sputtering source (500W or more),
Substrate cooling heating rotation mechanism (300 ° C normal use or more)
(2) Various conditions ・ Vacuum degree: 3.7 × 10 ⁻⁵ Pa
・ Target: Pure aluminum ・ Sputtering conditions (see Table 1)
Film formation thickness: The aluminum film formation condition based on experience is 0.66 μm / h, and an aluminum layer of 0.99 μm≈1 μm is formed after 90 minutes of film formation.

  Since the aluminum layer has a property that it is difficult to join with the solder, there is a risk of causing joint failure. Therefore, as shown in FIG. 8, a nickel plating layer 30b (for example, thickness: 3 μm) having a predetermined thickness is formed on the aluminum layer 30a, and a gold plating layer 30c (for example, thickness: 450 nm) is further formed thereon. ). This gold plating layer 30c can be satisfactorily bonded to the molten solder. By interposing a nickel plating layer 30b that can be satisfactorily fixed to both between the gold plating layer 30c and the aluminum layer 30a made of aluminum, it is possible to form the gold plating layer 30c that does not easily peel off on the aluminum layer 30a. it can.

  6 and 7, the vertical cross section of the wiring pattern 30 is shown along with the cross section of the glass substrate 20, whereas in FIG. 8, the horizontal cross section of the wiring pattern 30 is shown along with the cross section of the glass substrate 20. .

The nickel plating layer 30b can be formed by the following steps (1) to (8). The reason for performing zinc substitution twice in these steps is to make the coating of zinc uniform and to improve the adhesion.
(1) Degreasing: Removes processing oil and dirt adhering to the surface to be plated.
(2) Etching: The surface is dissolved thinly to remove a natural oxide film or the like.
(3) Desmut: removing impurities generated on the surface by etching.
(4) First zinc substitution: a thin zinc coating is formed on the surface of aluminum.
(5) Substitution layer peeling: Zinc coating is removed.
(6) Second zinc substitution: Again, a thin zinc coating is formed on the aluminum surface.
(7) Electroless Ni plating: Nickel is plated by a reduction reaction with hypophosphorous acid.
(8) Drying: removing moisture.

  Although not shown in FIGS. 3 and 4 for convenience, the wiring pattern 30 includes an element bonding electrode pad 31, an inter-substrate bonding electrode pad 32, and a wiring portion 33 that connects both pads, as well as a solder supply. The electrode pad 34 for use is formed. 9, 10, 11, and 12 respectively show the first example, the second example, the third example, the fourth example, and the element bonding electrode pad 31 of the solder supply electrode pad 34 in the wiring pattern 30. FIG. In any example, the solder supply electrode pad 34 has a larger area than the element bonding electrode pad 31. In the first example shown in FIG. 9, solder supply electrode pads 34 are formed so as to extend in parallel and linearly from the element bonding electrode pads 31 toward the outer substrate bonding electrode pads 32. Since the supply electrode pads 34 are directly connected to the element bonding electrode pads 31, the plurality of wiring patterns 30 are gathered in a compact manner. In the second example shown in FIG. 10 and the third example shown in FIG. 11, a square or circular solder supply electrode pad 34 is connected to the element bonding electrode pad 31 via a wiring portion. In the fourth example shown in FIG. 12, a solder supply electrode pad 34 extending in a wedge shape from an element bonding electrode pad 31 toward an inter-substrate bonding electrode pad (not shown) is formed. The solder supply electrode pad 34 is directly connected to the element bonding electrode pad 31. Since the solder supply electrode pad 34 is tapered from the inter-substrate bonding electrode pad side toward the element bonding electrode pad 31 side, the solder supply electrode pad 34 has a larger area than the plurality of small element bonding electrode pads 31. The solder supply electrode pads 34 can be connected in an independent state. Each of the wiring patterns 30 shown in these examples is configured such that the distances between the solder supply electrode pads 34 and the element bonding electrode pads 31 in the plurality of wiring patterns 30 are substantially equal to each other. In a plurality of combinations composed of the element bonding electrode pads 31 and the solder supply electrode pads 34 directly connected thereto, or a plurality of combinations composed of wiring portions connecting the both electrode pads and the both power pads, The area of each plane is the same.

  The solder supply electrode pad 34 can also serve as an inspection pad. For example, after joining the electrode of the VCSEL bare chip 10 and the wiring pattern 30, before mounting the VCSEL module 1 on the main substrate 90, the tip of the inspection probe of the inspection apparatus is attached to the solder supply electrode pad 34 of the wiring pattern 30. The contact state between the VCSEL bare chip 10 and the wiring pattern 30 can be inspected by bringing them into contact. Further, after the VCSEL module 1 is mounted on the main board 1, the tip of the inspection probe of the inspection device is brought into contact with the solder supply electrode pad 34 of the wiring pattern 30, so that the above-described driver IC and the wiring pattern 30 are electrically connected. Can also be inspected.

  After performing the pattern forming process, the bonding layer forming process is performed. In this bonding layer forming step, at least a printing step, a melting step, and a solidifying step are performed. In the printing process, the cream is applied to the surface of the plurality of solder supply electrode pads 34 of the wiring pattern 30 and the surface of the plurality of inter-substrate bonding electrode pads (32) by a printing method using a known print mask. Print the solder. In the melting step, the cream solder-printed glass substrate 20 is heated in a reflow furnace to melt the solder in the cream solder. At this time, the molten solder melted on the surface of the solder supply electrode pad 34 spreads wet while being transmitted from the solder supply electrode pad 34 onto the surface of the element bonding electrode pad 31 directly applied thereto. Alternatively, it spreads wet while being transmitted from the solder supply electrode pad 34 onto the surface of the element bonding electrode pad 31 through the wiring portion directly connected thereto. Eventually, not only on the surface of the element bonding electrode pad 31 but also in the element bonding electrode pad 31, the pad side surface rising from the substrate surface of the glass substrate 20 wets and spreads. Further, the molten solder melted on the surface of the inter-substrate bonding electrode pad (32) is not only on the surface of the inter-substrate bonding electrode pad but also the pad rising from the substrate surface of the glass substrate 20 in the inter-substrate bonding electrode pad. Spreads to the side as well. After the molten solder is wetted and spread in this manner, the glass substrate 20 is taken out of the reflow furnace and cooled to solidify the molten solder. As shown in FIG. Thus, the bonding layer 40 protruding outward from the outer edge of the electrode pad 31 in the surface direction can be obtained. Further, as shown in FIG. 14, it is possible to obtain a bonding layer 60 that protrudes outward from the outer edge in the surface direction of the inter-substrate bonding electrode pad 32.

  As shown in FIGS. 3 and 4, the plurality of element bonding electrode pads 31 of the wiring pattern 30 must be individually opposed to the plurality of small-area drive electrodes 12 in the VCSEL bare chip 10, respectively. Therefore, like the drive electrode 12, the area is very small. When cream solder having a thickness necessary for forming the bonding layer 40 is to be printed on the element bonding electrode pad 31 having such a small area, a printing mask is provided so as to correspond to each of the element bonding electrode pads 31. The cream solder cannot be removed well from the small-diameter hole provided in the. And it causes printing defects. Therefore, in the present embodiment, a solder supply electrode pad 34 having a larger area is formed in the vicinity of the element bonding electrode pad 31, and the solder in the cream solder printed thereon is melted to bond the element. The electrode pad 31 is wetted and spread. If the solder supply electrode pad 34 has a larger area than the element bonding electrode pad 31, the corresponding hole in the printing mask also has a relatively large diameter. You can get out.

  On the other hand, since the inter-substrate bonding electrode pad 32 of the wiring pattern 30 is originally formed in a relatively large area, the diameter provided on the print mask correspondingly becomes relatively large. Therefore, for each inter-substrate bonding electrode pad 32, a cream solder layer having a thickness necessary for forming the bonding layer 60 can be formed by the cream solder that is satisfactorily pulled out from the hole of the printing mask.

  If such a bonding layer forming step is performed, then a second cleaning step is performed. In this cleaning step, the wiring pattern forming surface of the wiring substrate is cleaned with an organic solvent such as isopropyl alcohol or ethanol that can dissolve the flux. By this cleaning, the flux remaining on the surfaces of the bonding layer 40 and the bonding layer 60 is removed, so that it is possible to avoid the occurrence of electrode deterioration of the VCSEL bare chip 10 and the main substrate 90 due to the residual flux.

  If a 2nd washing | cleaning process is implemented, a 2nd antireflection film formation process will be implemented next. In the second antireflection film forming step, the antireflection film 21 is formed on the entire surface of the wiring pattern formation surface of the glass substrate 20 by vapor deposition. The details of the forming method are the same as in the first antireflection film forming step. By the second antireflection film forming step, as shown in FIG. 15, not only the solid substrate surface existing in the wiring pattern non-formation region of the wiring pattern forming surface of the glass substrate 20, but also the wiring pattern 30 and the bonding layer 40, Although the antireflection film 21 is also formed on the surface 60, the antireflection film 21 may or may not be formed in regions other than the solid substrate surface.

  The first antireflection film forming process, the first cleaning process, the pattern forming process, the bonding layer forming process (printing process, melting process, solidifying process), the second cleaning process, and the second reflecting film forming process as described above. A wiring board is manufactured by the wiring board manufacturing process provided. Then, a VCSEL module 1 is obtained by performing a mounting process for mounting the VCSEL bare chip 10 on the obtained wiring board. In this mounting process, as shown in FIG. 16, the bonding layer 40 on the element bonding electrode pad of the wiring pattern 30 on the wiring board with the wiring pattern forming surface facing downward in the direction of gravity, and the drive electrode (not shown) of the VCSEL bare chip 10 The wiring board is placed on the VCSEL bare chip 10 so as to be in contact with each other. The laser light Lp is irradiated from above the wiring board toward the wiring pattern non-forming surface of the wiring board, and the laser light Lp after passing through the glass substrate 20 or the antireflection film 21 of the wiring board is used as the element of the wiring pattern 30. Touch the back of the bonding electrode pad. At this time, the laser beam Lp is directly applied not only to the back surface of the element bonding electrode pad but also to the protruding portion 40a protruding outside the outer edge of the element bonding electrode pad 31 in the bonding layer 40 shown in FIG. be able to. Thereby, the bonding layer 40 can be melted satisfactorily.

  In the mounting process described above, the laser beam Lp having a beam spot diameter adjusted to about 400 [μm] is irradiated toward the glass substrate 20. The element bonding electrode pads 31 are formed with a width of about 15 [μm], and on each surface of about 13 element bonding electrode pads 31 by one irradiation of the laser beam Lp. One laser beam Lp is applied to the bonding layer 40 to melt each bonding layer 40 simultaneously. When the surface shape of the bonding layer 40 changes with the melting, the region on the surface of the molten bonding layer 40 is shattered and melted out of the entire region of the antireflection film 21 on the wiring pattern forming surface of the glass substrate 20. It is taken into solder. Therefore, after the laser irradiation, the antireflection film 21 does not exist between the bonding layer 40 and the VCSEL 1 as shown in FIG. The antireflection film 21 is an ultrathin film having a thickness of 200 [nm], and its amount is very small compared to the molten solder, so that even if it is taken into the molten solder, there is no problem.

  The example in which the antireflection film 21 is formed over the entire area of the wiring pattern forming surface of the glass substrate 20 has been described. However, the antireflection film is applied only to the area facing the 40 light emitting portions of the VCSEL 1 in the entire area of the wiring pattern forming surface. 21 may be formed. As shown in FIG. 3, since this region exists in the center in the surface direction of the glass substrate 20, the antireflection film 21 can be formed only by masking the outer edges of the four corners.

  As the bonding layer forming step, the molten solder wetted and spread on the surface of the electrode pad is spread to the side surface of the electrode pad, thereby forming a bonding layer protruding outward from the outer edge in the surface direction on the electrode pad. Although an example has been described, it is possible to form a similar bonding layer by other methods. For example, the same bonding layer can be formed by performing a step of fixing a heat-meltable conductive material on the electrode pad by plating as the bonding layer forming step. However, in this case, first, after a wiring pattern having electrode pads and protruding from the substrate surface is formed on the surface of the glass substrate 20, it is necessary to perform a plating process on the wiring pattern. In this way, the bonding layer that protrudes outward from the outer edge of the electrode pad is formed by fixing the heat-meltable conductive material not only on the surface of the electrode pad of the wiring pattern but also on the side surface rising from the substrate surface. Can be formed. Even if a plating process is used, after the metal layer for the bonding layer is formed on the metal layer for the wiring pattern by the plating process, both metal layers are patterned by etching. Therefore, the bonding layer cannot protrude beyond the outer edge of the electrode pad.

  After the bonding layer 40 and the bonding layer 60 are formed, the resin 50 is fixed between the outer edge of the VCSEL bare chip 10 and the wiring board as shown in FIG. 1 in a draft in which nitrogen gas exists. Then, nitrogen gas is sealed in the sealed space 70 to obtain the VCSEL module 1.

  After the VCSEL module 1 is manufactured as described above, a substrate bonding step for bonding the VCSEL module 1 to the main substrate 90 is performed to obtain an electronic circuit substrate having both substrates. At this time, as shown in FIG. 17, the VCSEL bare chip 10 of the VCSEL module 1 is inserted into the opening 90a of the main board 90, and the outer edge of the VCSEL module 1 is hooked around the opening 90a of the main board 90. The VCSEL module 1 is placed on the main substrate 90. In the state where the bonding layer 60 on the wiring pattern 30 of the VCSEL module 1 and the module bonding electrode pad (not shown) of the main substrate 90 are in contact with each other through the antireflection film 21, The laser beam Lp is irradiated toward the wiring pattern non-formation surface. Thereafter, the laser beam Lp that has passed through the glass substrate 20 or the antireflection film 21 of the VCSEL module 1 is applied to the back surface of the inter-substrate bonding electrode pad (32) of the wiring pattern 30. At this time, the laser beam Lp is directly applied not only to the back surface of the inter-substrate bonding electrode pad but also to the protruding portion 60a protruding outside the outer edge of the inter-substrate bonding electrode pad 33 in the bonding layer 60 shown in FIG. be able to. Thereby, the joining layer 60 can be favorably melted. At this time, a region located on the surface of the bonding layer 60 in the entire region of the antireflection film 21 is melted together with the solder to form an alloy.

  When the VCSEL module 1 and the main substrate 90 are joined by laser irradiation, as shown in FIG. 5, the ground electrode 14 formed on the back surface of the VCSEL bare chip 10 and the ground electrode 91 of the main substrate 90 are connected with a conductive adhesive. 93 is connected.

Sectional drawing which shows an example of the VCSEL module which is an electronic circuit board which concerns on embodiment. The top view which shows the VCSEL one structural example of the same VCSEL module. The top view which shows the example of 1 structure of the wiring board of the VCSEL module. The top view which shows the same VCSEL module. Sectional drawing which shows the electronic circuit board which mounted the VCSEL module on the main board | substrate. Sectional drawing which shows the glass substrate of the same wiring board. Sectional drawing which shows the cross section of the glass substrate, and the longitudinal cross-section of the wiring pattern formed in the one surface of this. The expanded sectional view which shows the cross section of the glass substrate, and the cross section of the wiring pattern. The enlarged plan view which shows the 1st example of the electrode pad for solder supply in the same wiring pattern. The enlarged plan view which shows the 2nd example of the electrode pad for the said solder supply. The enlarged plan view which shows the 3rd example of the electrode pad for the said solder supply. The enlarged plan view which shows the 4th example of the electrode pad for the solder supply. The expanded sectional view which shows the cross section which fractured | ruptured the same wiring board in the location of the electrode pad for element joining. The expanded sectional view which shows the cross section which fractured | ruptured the same wiring board in the location of the electrode pad for board | substrate joining. Sectional drawing which shows the wiring board. Sectional drawing which shows the same wiring board and VCSEL. Sectional drawing which shows the same VCSEL module and main board | substrate with which the joint process is performed mutually.

Explanation of symbols

1: VCSEL module 10: VCSEL (light emitting element)
20: Glass substrate (substrate)
21: Antireflection film 30: Wiring pattern 31: Electrode pad for element bonding 32: Electrode pad for bonding between substrates 34: Wiring part 35: Electrode pad for supplying solder 40: Bonding layer 60: Bonding layer

Claims (6)

An electronic component having a light emitting unit that converts an electrical signal into light to emit light, or a light receiving unit that converts received light into an electrical signal;
A substrate made of a light-transmitting material, and an antireflection film made of a light-transmitting material formed on both surfaces of the substrate, respectively, and allowing the light emitted from the light-emitting portion to pass through itself, Alternatively, a light transmission plate disposed opposite to the electronic component so as to transmit the light before entering the light receiving section to itself,
A wiring pattern formed in a non-opposing region with the light emitting portion or the light receiving portion in the entire region on one surface of the light transmission plate;
The electronic component has a driving electrode for supplying a driving voltage to the light emitting unit or the light receiving unit at a position facing the wiring pattern;
In the photoelectric conversion module in which the wiring pattern and the driving electrode facing each other are bonded with a conductive bonding material,
The wiring pattern is formed by directly adhering to the solid surface of the substrate on the one surface side of the light transmission plate, and the wiring pattern non-forming region of the substrate is formed on the one surface side. Of these, the antireflection film is formed at least in a region facing the light emitting portion or the light receiving portion. The photoelectric conversion module according to claim 1,
A glass substrate made of barium borosilicate glass is used as the substrate, and the wiring pattern is made of aluminum or an aluminum alloy containing aluminum as a main component at a location that is directly fixed to a solid surface of the substrate. A photoelectric conversion module characterized by being formed. The photoelectric conversion module according to claim 2,
As the wiring pattern, an aluminum layer made of aluminum or an aluminum alloy that is directly fixed to the solid surface of the substrate, a nickel layer made of nickel laminated on the surface of the aluminum layer, and laminated on the surface of the nickel layer A photoelectric conversion module comprising a multi-layer structure including a gold layer made of gold. The photoelectric conversion module according to claim 3.
As the antireflection film, a photoelectric conversion module, characterized in that the formation of the a two-layer structure having a SiO film made of SiO, and SiO ₂ film made of SiO ₂ formed on this surface. An electronic component having a light emitting unit that converts an electrical signal into light to emit light, or a light receiving unit that converts received light into an electrical signal;
A substrate made of a light-transmitting material, and an antireflection film made of a light-transmitting material formed on both surfaces of the substrate, respectively, and allowing the light emitted from the light-emitting portion to pass through itself, Alternatively, a light transmission plate disposed opposite to the electronic component so as to transmit the light before entering the light receiving section to itself,
A wiring pattern formed in a non-opposing region with the light emitting portion or the light receiving portion in the entire region on one surface of the light transmission plate;
The electronic component has a driving electrode for supplying a driving voltage to the light emitting unit or the light receiving unit at a position facing the wiring pattern;
In a photoelectric conversion module manufacturing method for manufacturing a photoelectric conversion module in which the wiring patterns facing each other and the drive electrodes are bonded with a conductive bonding material,
The step of forming the antireflection film on the solid substrate surface on the surface of the substrate on which the wiring pattern is not formed, and the wiring on the surface of the solid substrate on the surface of the substrate on which the wiring pattern is formed At least the light emitting portion or the pattern forming step in which the pattern is directly fixed and a solid substrate surface existing in the wiring pattern non-formation region on the surface of the substrate on which the wiring pattern is formed. The process of forming the said antireflection film in the area | region facing a light-receiving part is implemented, The photoelectric conversion module in any one of Claims 1 thru | or 4 is obtained as said photoelectric conversion module, The photoelectric conversion module manufacture characterized by the above-mentioned Method. In the photoelectric conversion module manufacturing method of claim 5,
As the substrate, a glass substrate made of barium borosilicate glass is used,
In the pattern forming step, after patterning an aluminum layer made of aluminum or an aluminum alloy mainly composed of aluminum formed on the solid surface of the glass substrate by a sputtering method, the patterned aluminum layer The photoelectric conversion module according to claim 3 is manufactured by sequentially laminating a nickel plating layer by nickel plating and a gold plating layer by gold plating on the surface to form the wiring pattern having a multilayer structure. Photoelectric conversion module manufacturing method.

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