JP2020166108A - Optical/electrical composite transmission module - Google Patents

Abstract

To provide an optical/electrical composite transmission module capable of preventing damage to an optical element.SOLUTION: An optical/electrical composite transmission module 1 is provided, comprising an optical/electrical hybrid substrate 2 consisting of an optical waveguide 6 and an electric circuit board 7 arranged in order in a thickness direction, a printed wiring board 3 joined with the electrical circuit board 7 to be electrically connected to the electric circuit board 7, an optical element 4 mounted on the optical/electrical hybrid substrate 2 to be optically connected to the optical waveguide 6 and electrically connected to the electric circuit board 7, and a joint member 27 covering an electrical connection 29 between the printed wiring board 3 and the electric circuit board 7 to join the printed wiring board 3 and the electric circuit board 7 together, the joint member 27 being a cured product of a material that is curable when heated at 100°C for 2 hours.SELECTED DRAWING: Figure 2

Description

The present invention relates to an opto-electric composite transmission module.

Conventionally, an optical-electric composite transmission module including an optical waveguide and an electric circuit board, including an optical-electric mixed circuit board on which an optical element such as VCSEL is mounted, and a printed wiring board electrically connected to the electric circuit board has been proposed. (See, for example, Patent Document 1).

In the optical-electric composite transmission module of Patent Document 1, as a method of joining the optical-electric mixed circuit board and the printed wiring board, bumps are provided between the terminals, and then the opto-electric mixed circuit board and the printed wiring board are made of a non-conductive resin. Is poured and then heated in a heating furnace at 150 ° C.

Japanese Unexamined Patent Publication No. 2008-310066

However, the method described in Patent Document 1 has a problem that the optical element is damaged during heating.

The present invention provides an opto-electric composite transmission module capable of suppressing damage to an optical element.

In the present invention (1), an optical-electric mixed circuit board having an optical waveguide and an electric circuit board in order in the thickness direction and a printed wiring board joined to the electric circuit board so as to be electrically connected to the electric circuit board. The optical element mounted on the optical / electric mixed circuit board, the printed wiring board, and the electric circuit board so as to be optically connected to the optical waveguide and electrically connected to the electric circuit board. The printed wiring board is provided with a joining member for joining the printed wiring board and the electric circuit board, and the joining member is a cured product of a material that can be cured by heating at 100 ° C. for 2 hours. Includes an opto-electric composite transmission module.

In the opto-electric composite transmission module, the material can be cured by heating at 100 ° C. for 2 hours, so that it covers the electrical connection part of the printed wiring board and the electric circuit board, and then suppresses the damage of the optical element. It can be heated under a low temperature condition to form a cured product, which can join the printed wiring board and the electric circuit board.

Therefore, in this opto-electric composite transmission module, damage to the optical element can be suppressed.

In the present invention (2), the photoelectric composite according to (1), wherein the cured product is a cured product obtained by heating the material, or is a cured product obtained by heating the material and irradiating with active energy rays. Includes transmission module.

Since the cured product is a cured product obtained by heating the material or a cured product obtained by heating the material and irradiating with active energy rays, the joining member which is the cured product by low-temperature heating capable of suppressing damage to the optical element. Can be formed.

The present invention (3) includes the opto-electric composite transmission module according to (1) or (2), wherein the joining member has a coefficient of linear expansion of 70 ppm or less.

In the optoelectric composite transmission module, since the joining member has a linear expansion coefficient of 70 ppm or less, warpage of the optoelectric mixed substrate can be suppressed. Therefore, the bondability of the printed wiring board and the electric circuit board by the joining member is excellent.

The present invention (4) includes the opto-electric composite transmission module according to any one of (1) to (3), wherein the material of the optical waveguide is an epoxy resin.

In this opto-electric composite transmission module, since the material of the optical waveguide is an epoxy resin, it is excellent in heat resistance and light transmission.

In the present invention (5), the electric circuit board is provided with a first terminal, the printed wiring board is provided with a second terminal, and the connection portion is a conductive member in contact with the first terminal and the second terminal. Includes the opto-electric composite transmission module according to any one of (1) to (4).

In this opto-electric composite transmission module, since the connection portion includes a conductive member that contacts the first terminal and the second terminal, the electrical connection reliability of the printed wiring board and the electric circuit board is excellent.

In the opto-electric composite transmission module of the present invention, damage to the optical element can be suppressed.

FIG. 1 is a plan view of an embodiment of the opto-electric composite transmission module of the present invention. FIG. 2 is a side sectional view of the opto-electric composite transmission module shown in FIG. 1 along XX lines.

An embodiment of the opto-electric composite transmission module of the present invention will be described with reference to FIGS. 1 and 2.

The opto-electric composite transmission module 1 has a substantially plate (or sheet) shape extending in the longitudinal direction. The photoelectric composite transmission module 1 includes a photoelectric mixed circuit board 2, a printed wiring board 3, an optical element 4, and a joint portion 5.

The photoelectric mixed substrate 2 has a substantially plate shape extending in the longitudinal direction. The photoelectric mixed board 2 includes an optical waveguide 6 and an electric circuit board 7 in order toward the upper side (an example of one side in the thickness direction).

The optical waveguide 6 is located in the lower portion of the photoelectric mixed mounting substrate 2. The optical waveguide 6 has a substantially sheet shape extending in the longitudinal direction. The optical waveguide 6 includes an underclad layer 8, a core layer 9, and an overclad layer 10 in this order toward the lower side (an example of the other side in the thickness direction). The peripheral surface of the core layer 9 in a normal cross-sectional view is covered with the underclad layer 8 and the overclad layer 10. A mirror 11 is formed at one end of the core layer 9 in the longitudinal direction. Examples of the material of the optical waveguide 6 include transparent materials such as epoxy resin, acrylic resin, and silicone resin. Preferably, an epoxy resin is used from the viewpoint of heat resistance and optical signal transmission.

The electric circuit board 7 is arranged above the optical waveguide 6. The electric circuit board 7 has a substantially plate shape extending in the longitudinal direction. The electric circuit board 7 includes a metal support layer 12, a base insulating layer 13, and a first conductor layer 14 in this order toward the upper side. The metal support layer 12 is formed in a region corresponding to the first conductor layer 14. The base insulating layer 13 has the same plan view shape as the electric circuit board 7.

The first conductor layer 14 includes a first terminal 15, a third terminal 17, and a first wiring 16.

A plurality of the first terminals 15 are arranged at one end in the longitudinal direction of the optical / electrical mixed substrate 2. Specifically, the plurality of first terminals 15 are arranged at one end in the longitudinal direction in a joint area 18 that overlaps with the printed wiring board 3 when projected in the vertical direction. The plurality of first terminals 15 are arranged in a substantially U-shape so as to surround the plurality of third terminals 17 described below in a plan view. The joining area 18 has a substantially U-shape that is open toward the other side in the longitudinal direction at one end in the longitudinal direction in a plan view. The plurality of first terminals 15 are arranged so as to be spaced apart from each other in the joining area 18.

A plurality of the third terminals 17 are arranged at the center of one end in the longitudinal direction of the electric circuit board 7 in a plan view. The plurality of third terminals 17 are spaced apart from the first terminal 15. The plurality of third terminals 17 are arranged so as to be spaced apart from each other in the longitudinal direction and the width direction.

The first wiring 16 electrically connects each of the plurality of first terminals 15 and each of the plurality of third terminals 17.

Although not shown, the electric circuit board 7 may be provided with a cover insulating layer covering the first wiring 16 on the upper surface of the base insulating layer.

The printed wiring board 3 is electrically connected to and joined to the electric circuit board 7.
The printed wiring board 3 extends in the longitudinal direction and has a substantially flat plate shape that is wider than the optical / electric mixed circuit board 2. In the printed wiring board 3, the center of the other end in the longitudinal direction in the width direction is cut into a substantially rectangular shape in a plan view. As a result, the printed wiring board 3 includes two extension portions 19 extending to the other side in the longitudinal direction and a connecting portion 20 for connecting the base end portions of the two extension portions 19. The two extending portions 19 and the connecting portion 20 include a joining area 18 of the photoelectric mixed substrate 2 when projected in the vertical direction. The two extension portions 19 are arranged on both sides of the third terminal 17 in the width direction. The printed wiring board 3 includes a support plate 21 and a conductor circuit 22.

The support plate 21 has a substantially plate shape extending in the longitudinal direction and having a notch at the center of the other end in the longitudinal direction. Examples of the material of the support plate 21 include a hard material such as a glass fiber reinforced epoxy resin.

The conductor circuit 22 includes a second terminal 23, a fourth terminal 24, and a conductor wire 25.

A plurality of second terminals 23 are arranged below the support plate 21. Each of the plurality of second terminals 23 is arranged to face each other on the upper side of each of the plurality of first terminals 15 of the opto-electric mixed mounting substrate 2 at intervals. Each of the plurality of second terminals 23 coincides with each of the plurality of first terminals 15 when projected in the vertical direction. The plurality of second terminals 23 are arranged in a substantially U-shape at two extending portions 19 and connecting portions 20 of the support plate 21 at intervals from each other.

The fourth terminal 24 is arranged on one end surface in the longitudinal direction of the support plate 21.

The conductor wire 25 electrically connects the second terminal 23 and the fourth terminal 24. The conductor wire 25 includes a via 26 that penetrates the support plate 21 in the vertical direction. The lower edge of the via 26 contacts the upper edge of the second terminal 23.

Examples of the material of the conductor circuit 22 include a conductor material such as copper.

The optical element 4 is mounted on the central portion of the upper surface of one end portion in the longitudinal direction of the photoelectric mixed mounting substrate 2. Specifically, the optical element 4 is surrounded by a substantially U-shaped joint area 18 in a plan view. The optical element 4 includes a light inlet / outlet and an electrode (not shown). The doorway is optically connected to the mirror 11. The electrode is electrically connected to the third terminal 17. As a result, the optical element 4 is optically connected to the optical waveguide 6 and electrically connected to the electric circuit board 7.

The joint portion 5 includes a conductive member 27 and a joint member 28.

The conductive member 27 is arranged between the first terminal 15 and the second terminal 23 and is in contact with them. The conductive member 27 connects the first terminal 15 and the second terminal 23 in the vertical direction. A plurality of conductive members 27 are provided corresponding to the plurality of first terminals 15 and the plurality of second terminals 23. The conductive member 27 contacts, for example, the upper surface of the first terminal 15 and the lower surface of the third terminal 17, but does not contact the peripheral side surfaces thereof.

The conductive member 27, the first terminal 15, and the third terminal 17 are electrically conductive, and therefore form a connecting portion 29 that electrically connects the printed wiring board 3 and the electric circuit board 7. The connecting portion 29 includes a conductive member 27, a first terminal 15 and a third terminal 17.

A plurality of connecting portions 29 are provided corresponding to a plurality of first terminals 15, a plurality of third terminals 17, and a plurality of conductive members 27.

Examples of the material of the conductive member 27 include metals such as gold and alloys (solder and the like).

The joining member 28 covers a plurality of connecting portions 29 and joins the printed wiring board 3 and the electric circuit board 7.

Specifically, the joining member 28 is arranged in the entire joining area 18, and is filled between the photoelectric mixed mounting substrate 2 and the printed wiring board 3 corresponding to the joining area 18. The joining member 28 covers the side surfaces of the plurality of connecting portions 29. One joining member 28 is provided for a plurality of connecting portions 29 in the joining area 18. The outer shape of the joining member 28 in a plan view is the same as that of the joining area 18.

The joining member 28 is a cured product of the curable composition. In other words, the material (raw material) of the joining member 28 is a curable composition, and the cured product obtained by curing the curable composition is the joining member 28.

The curable composition can be cured by heating at 100 ° C. for 2 hours.

Specifically, the curable composition contains a curable resin.

Examples of the curable resin include thermosetting resins that can be cured by heating, for example, heat-photocurable resins that can be cured by heating and irradiation with light (active energy rays), such as moisture-curable resins. Be done. These can be used alone or in combination of two or more. The types of curable resins described above are not clearly distinguished.

Examples of the curable resin include epoxy resin, silicone resin, urethane resin, polyimide resin, urea resin, melamine resin, and unsaturated polyester resin. These can be used alone or in combination of two or more. When the curable resin contains an epoxy resin, the curable composition is an epoxy resin composition.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol AF type epoxy resin, and biphenyl type epoxy. Bifunctional epoxy resins such as resins, naphthalene type epoxy resins, fluorene type epoxy resins, phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, trishydroxyphenylmethane type epoxy resins, and tetraphenylol ethane type epoxy resins and polyfunctional Epoxy resin can be mentioned. Examples of the epoxy resin include a hydantoin type epoxy resin, a trisglycidyl isocyanurate type epoxy resin, and a glycidylamine type epoxy resin. These can be used alone or in combination of two or more.

Examples of the silicone resin include straight silicone resins such as methyl silicone resin, phenyl silicone resin and methyl phenyl silicone resin, for example, alkyd-modified silicone resin, polyester-modified silicone resin, urethane-modified silicone resin, epoxy-modified silicone resin and acrylic-modified silicone. Examples thereof include modified silicone resins such as resins. These can be used alone or in combination of two or more.

When the curable composition is an epoxy resin composition, the curable composition can further contain a curing agent such as an imidazole compound or an amine compound. Further, the curable composition can contain a curing accelerator such as a urea compound, a tertiary amine compound, a phosphorus compound, a quaternary ammonium salt compound, and an organometallic salt compound.

Further, when the curable resin is a thermosetting resin, the curable composition can contain, for example, a photoinitiator.

In addition, the curable composition can contain reactive monomers.

Further, the curable composition may contain a filler in addition to the above.

The filler is not particularly limited, and is, for example, an inorganic filler such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, quartz glass, talc, silica, aluminum nitride, silicon nitride, boron nitride, for example, acrylic resin particles. , Organic fillers such as silicone resin particles.

The curable composition can further contain additives such as a coupling agent and a lubricant in an appropriate ratio.

The ratio of each component in the curable composition is appropriately set according to the application and purpose. The proportion of the curable resin in the curable composition is, for example, 50% by mass or more and 90% by mass or less. The proportion of the curing agent in the curable composition is, for example, 1% by mass or more, for example, 40% by mass or less. The proportion of the curing accelerator in the curable composition is, for example, 0.5% by mass or more, for example, 10% by mass or less. The proportion of the reactive monomer in the curable composition is, for example, 1% by mass or more and 10% by mass or less. The proportion of the filler in the curable composition is, for example, 1% by mass or more and 40% by mass or less.

Then, as described above, the above-mentioned curable composition can be cured by heating at 100 ° C. for 2 hours. Curing means complete curing, which is C-stage, rather than semi-curing, which is B-stage.

On the contrary, the curable composition is not cured by heating at 100 ° C. for 2 hours as described above, but can be cured only by heating conditions harsher than the above heating conditions (for example, heating at 150 ° C. for 2 hours). In the case of a curable composition, the optical element 4 is damaged when the curable composition is cured under harsh heating conditions.

Further, the curable composition can be cured only by heating at 100 ° C. for 2 hours without irradiating light, even if the heat-photocurable resin can be cured by heating and irradiation with light. Resin.

Preferably, the curable composition can be cured by heating at 80 ° C. for 2 hours.

Also, preferably, the curable composition can be cured by heating at 100 ° C. for 1 hour.

The coefficient of thermal expansion of the joining member 28 is, for example, 150 ppm or less, preferably 100 ppm or less, more preferably 70 ppm or less, still more preferably 50 ppm or less. The coefficient of thermal expansion of the joining member 28 is, for example, 0 ppm or more.

If the coefficient of thermal expansion of the joining member 28 is less than the above-mentioned upper limit, the warp of the photoelectric mixed substrate 2 can be suppressed. Therefore, the jointability of the printed wiring board 3 and the electric circuit board 7 by the joining member 28 is excellent.

Next, a method of manufacturing the opto-electric composite transmission module 1 will be described.

First, each of the optical / electric mixed circuit board 2, the printed wiring board 3, and the optical element 4 is prepared.

A curable composition (raw material for the joining member 28) is prepared. Specifically, each of the above-mentioned components is mixed in the above-mentioned ratio.

Next, the optical element 4 is mounted on the optical / electric mixed mounting substrate 2. An electrode (not shown) of the optical element and a third terminal 17 of the photoelectric mixed substrate 2 are electrically connected. At the same time, the entrance / exit of light (not shown) of the optical element and the mirror 11 are optically connected.

Next, the conductive member 27 is arranged on the upper surface of the first terminal 15.

Next, the printed wiring board 3 is arranged with respect to the photoelectric mixed mounting board 2 (the photoelectric mixed mounting board 2 on which the optical element 4 is mounted) so that the second terminal 23 comes into contact with the upper end of the conductive member 27.

Subsequently, the bonding area of the photoelectric mixed mounting substrate 2 and the printed wiring board 3 so that the curable composition (raw material of the bonding member 28) comes into contact with the side surfaces of the first terminal 15, the second terminal 23, and the conductive member 27. 18 is filled (injected).

Then, if the curable composition contains a thermosetting resin, the curable composition is heated. The heating conditions are, for example, low temperature conditions in which the optical element 4 is not damaged, for example, 130 ° C. or lower, preferably 110 ° C. or lower, more preferably 100 ° C. or lower, still more preferably 80 ° C. or lower. Further, for example, the temperature is 50 ° C. or higher. The heating time is, for example, less than 2 hours, preferably 1 hour or less, more preferably 45 minutes or less, still more preferably 30 minutes or less, and particularly preferably 15 minutes or less.

Specifically, if the heating time is 130 ° C. or less, the heating condition is set to 15 minutes or less. If the heating time is 110 ° C. or less, the heating condition is set to 30 minutes or less. If the heating time is 100 ° C. or less, the heating condition is set to 45 minutes or less. If the heating time is 80 ° C. or less, the heating condition is set to 1 hour or less.

In addition, when the curable composition contains a heat-photocurable resin and a photoinitiator, the curable composition is irradiated with light and heated.

For example, a curable composition containing a heat-photocurable resin and a photoinitiator is first irradiated with light and then the curable composition is heated.

Examples of light include ultraviolet rays.

The amount of light energy is not particularly limited, and is, for example, 10 J / m ² or more, preferably 100 J / m ² or more, and for example, 10,000 J / m ² or less, preferably 1,000 J / m. It is ² or less.

In this case, it is permissible for the curable composition to partially include a portion not irradiated with light in the bonding area 18.

The curable composition is then heated. The heating conditions may be the same as those when the curable composition contains a thermosetting resin, and are preferably milder. For example, it is 110 ° C. or lower, preferably 100 ° C. or lower, more preferably 80 ° C. or lower, still more preferably 70 ° C. or lower, and for example, 40 ° C. or higher. The heating time is, for example, less than 1 hour, preferably 30 minutes or less, more preferably 15 minutes or less, still more preferably 10 minutes or less, and particularly preferably 5 minutes or less.

Specifically, if the heating time is 110 ° C. or less, the heating condition is set to 5 minutes or less. If the heating time is 100 ° C. or less, the heating conditions are set to 10 minutes or less. If the heating time is 80 ° C. or less, the heating condition is set to 15 minutes or less. If the heating time is 70 ° C. or less, the heating condition is set to 30 minutes or less.

The portion not irradiated with light by this heating is cured by the next heating.

By the above heating, the conductive member 27 is reflowed, and the first terminal 15 and the second terminal 23 are electrically connected via the conductive member 27. The connecting portion 29 is formed from the first terminal 15, the second terminal 23, and the reflowed conductive member 27.

A cured product obtained by curing the curable composition is produced by the above heating or heating and irradiation with light, and the bonded member 28, which is the cured product, is formed by the photoelectric mixed circuit board 2 and the printed wiring board 3 in the bonding area 18. And are joined (bonded). At the same time, the joining member 28 reinforces the plurality of connecting portions 29.

When the curable composition contains a moisture-curable resin, the conductive member 27 is reflowed by heating in advance to form the connection portion 29, and then the curable composition is injected around the connection portion 29. Then, leave it under the condition of normal temperature and humidity (or high humidity). The leaving time is, for example, 10 hours or more, for example, 100 hours or less.

In this opto-electric composite transmission module, the curable composition, which is a material, can be cured by heating at 100 ° C. for 2 hours, so that the electrical connection portion 29 of the printed wiring board 3 and the electric circuit board 7 is connected. The bonding member 28, which is a cured product, can be formed by coating and then heating under low temperature conditions that can suppress damage to the optical element 4.

Therefore, in this opto-electric composite transmission module 1, damage to the optical element 4 can be suppressed.

Further, in the opto-electric composite transmission module 1, since the joining member 28 is a cured product by heating the material or a cured product by heating the material and irradiating light, damage to the optical element 4 can be suppressed. The joining member 28 can be formed by low temperature heating.

It is conceivable that the joining member 28 is a cured product obtained only by irradiation with light. In this configuration, the curable composition contains a photocurable resin, and the curable composition is irradiated with light in the manufacturing process. In the above step, due to the arrangement and / or shape of the bonding area 18, the entire curable composition cannot be irradiated with light, so that an uncured portion remains. Therefore, this configuration is unsuitable.

Further, in the opto-electric composite transmission module 1, if the joining member 28 has a linear expansion coefficient of 70 ppm or less, the warp of the opto-electric mixed substrate 2 can be suppressed. Therefore, the jointability of the printed wiring board 3 and the electric circuit board 7 by the joining member 28 is excellent.

In this opto-electric composite transmission module 1, if the material of the optical waveguide 6 is an epoxy resin composition, it is excellent in heat resistance and optical signal transmission.

In this opto-electric composite transmission module 1, since the connection portion 29 includes the conductive member 27 that contacts the first terminal 15 and the second terminal 23, the electrical connection reliability of the printed wiring board 3 and the electric circuit board 7 is improved. Excellent.

<Modification example>
In each of the following modifications, the same reference numerals will be given to the same members and processes as in the above-described embodiment, and detailed description thereof will be omitted. In addition, each modification can exert the same effect as that of one embodiment, except for special mention. Further, one embodiment and a modification thereof can be appropriately combined.

In the manufacturing method of one embodiment, the conductive member 27 is first arranged at the first terminal 15. For example, the conductive member 27 is first arranged at the second terminal 23, and then the lower end of the conductive member 27 and the first terminal. It can also be brought into contact with the top surface of 15.

In one embodiment, the plan view shape of the joint area 18 is substantially U-shaped, but is not limited to this, and may be, for example, a long rectangular shape in the width direction or a long rectangular shape in the longitudinal direction. Good.

When the thermosetting resin is cured, the order of light irradiation and heating is not limited to the above, and for example, it may be first heated and then irradiated with light.

Examples and comparative examples are shown below, and the present invention will be described in more detail. The present invention is not limited to Examples and Comparative Examples. In addition, specific numerical values such as the compounding ratio (ratio), physical property values, and parameters used in the following description are the compounding ratios (ratio) corresponding to those described in the above-mentioned "Form for carrying out the invention". ), Physical property values, parameters, etc. can be replaced with the upper limit (numerical value defined as "less than or equal to" or "less than") or the lower limit (numerical value defined as "greater than or equal to" or "excess").

First, the raw materials of the used joining member 28 are described below.
Curable composition A: SUF1575 (manufactured by Namics)
Curable composition B: Heat-photocurable epoxy resin curable composition C: TB2274S (manufactured by ThreeBond Co., Ltd.)
Curable composition D: 877776SL1 (manufactured by Kyoritsu Chemical Industry Co., Ltd.)
Curable composition E: TB2280C (manufactured by ThreeBond Co., Ltd.)
Examples 1 to 4, Comparative Example 1
The opto-electric composite transmission module 1 of one embodiment was manufactured.

The raw materials shown in Table 1 were cured by the methods shown in Table 1 to form a bonded member 28 as a cured product.

In addition, all the optical waveguides were formed of epoxy resin.

Comparative Example 2
An attempt was made to manufacture the opto-electric composite transmission module 1 of one embodiment. The raw materials shown in Table 1 were heated by the method shown in Table 1 (100 ° C., 2 hours), but the raw materials did not cure and the joining member 28 as a cured product could not be formed. That is, the opto-electric composite transmission module 1 could not be manufactured.

<Evaluation>
The following items were evaluated.

(1) Damage to Optical Elements The optical elements 4 in the opto-electric composite transmission module 1 of Examples 1 to 4 and Comparative Example 1 were observed and evaluated according to the following criteria.
◯: No damage to the optical element 4 was observed.
X: Damage to the optical element 4 was observed.

(2) Curing tests A and B
The raw materials of Examples 1 to 4 were cured under the heating conditions of the curing test A shown in Table 1.

The raw material of Comparative Example 1 was cured under the heating conditions of the curing test B shown in Table 1.

An attempt was made to cure the raw material of Comparative Example 2 under the heating conditions of the curing test A shown in Table 1, but the material was not cured.

(3) Warpage The opto-electric mixed substrate 2 near the junction area 18 of the opto-electric composite transmission module 1 of Examples 1 to 4 and Comparative Example 1 was observed, and the warp was evaluated as follows.
◯: No warpage was observed.
Δ: Slight warpage was observed.

(4) Coefficient of Thermal Expansion of Joining Member The coefficient of thermal expansion of the joining member 28 in the photoelectric composite transmission module 1 of Examples 1 to 4 and Comparative Example 1 was obtained.

1 Optical-electric composite transmission module 2 Optical-electric mixed circuit board 3 Printed wiring board 4 Optical element 6 Optical waveguide 7 Electric circuit board 15 1st terminal 23 2nd terminal 27 Conductive member 28 Joint member 29 Connection part

Claims (5)

An optical and electric mixed board having an optical waveguide and an electric circuit board in order in the thickness direction,
A printed wiring board bonded to the electric circuit board so as to be electrically connected to the electric circuit board.
An optical element mounted on the optical / electrical mixed substrate so as to be optically connected to the optical waveguide and electrically connected to the electric circuit board.
A joining member for covering the printed wiring board and the electrical connection portion of the electric circuit board and joining the printed wiring board and the electric circuit board is provided.
The photoelectric composite transmission module is characterized in that the joining member is a cured product of a material that can be cured by heating at 100 ° C. for 2 hours. The opto-electric composite transmission module according to claim 1, wherein the cured product is a cured product obtained by heating the material, or is a cured product obtained by heating the material and irradiating the active energy ray. .. The optoelectric composite transmission module according to claim 1 or 2, wherein the joining member has a coefficient of linear expansion of 70 ppm or less. The opto-electric composite transmission module according to any one of claims 1 to 3, wherein the material of the optical waveguide is an epoxy resin. The electric circuit board includes a first terminal.
The printed wiring board includes a second terminal.
The opto-electric composite transmission module according to any one of claims 1 to 4, wherein the connecting portion includes a conductive member in contact with the first terminal and the second terminal.