JPH08125216A - Manufacture of photocoupler - Google Patents

Abstract

PURPOSE: To obtain an efficient, ultra-compact, and inexpensive photocoupler by joining transparent insulation resin and opaque insulation resin without any interface. CONSTITUTION: A method of manufacturing a photocoupler comprises a process for die-bonding a light emitting element 3 and a photodetector 4 to individual metal lead frames 1 and 2 and laying out the light-emitting element 3 and the photodetector 4 opposingly so that they can be optically coupled and a process for forming a light path between the light-emitting element 3 and the photodetector 4 by performing transfer formation with transparent epoxy resin 5 while the elements 3 and 4 are laid out opposingly. It also is provided with a process for laid out them in a plasma container 11, generating plasma, and performing plasma ashing treatment to the surface of the transparent epoxy resin 5 and a process for performing transfer formation of the outer-periphery part of the transparent epoxy resin 5 with an opaque epoxy resin 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling device (photocoupler) in which an optical path is formed between a light emitting element and a light receiving element via a translucent insulating resin, and these are covered with a light shielding insulating resin. ), Particularly to a method for manufacturing a microminiature optical coupling device.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram of a general optical coupling device, and FIG. 9 is a vertical sectional view of FIG. In addition, FIG.
FIG. 10 is a diagram showing a manufacturing process of the optical coupling device shown in FIG. 9;

As shown in FIGS. 8 and 9, the optical coupling device is provided with a G
The light emitting element 3 such as an aAs infrared light emitting diode and the light receiving element 4 such as a phototransistor are separately mounted, and the light emitting element 3 and the light receiving element 4 are arranged to face each other so as to be optically coupled to each other. Both the elements 3 and 4 are resin-sealed with a translucent insulating resin 5 such as an epoxy resin, a silicone resin, or a polyimide resin in order to protect the elements and improve the optical external quantum efficiency. The outer peripheral portion of 5 has a structure which is resin-sealed with a light-shielding insulating resin 6 such as an epoxy resin or a polyimide resin in order to protect the metal lead frames 1 and 2 and to shield the entry of ambient light.

A method of manufacturing the above-mentioned optical coupling device will be described below with reference to FIG.

First, as shown in FIG. 10A, the light emitting element 3 and the light receiving element 4 are die-bonded to individual metal lead frames 1 and 2 via a silver paste or the like to form the light emitting element 3 and the light receiving element 4. Are arranged to face each other optically.

Next, as shown in FIG. 10 (b), the optical paths between the light receiving and emitting elements 3 and 4 are formed by transfer molding with a translucent epoxy resin 5 in a state where both the elements 3 and 4 are arranged to face each other. Form.

Next, as shown in FIG. 10 (c), the outer peripheral portion of the translucent epoxy resin 5 is transfer-molded with, for example, a light-shielding epoxy resin 6 to obtain a finished product.

FIG. 11 is a longitudinal sectional view showing the structure of another general optical coupling device. Regarding the structure of the optical coupling device and the manufacturing method thereof, only the points different from the structure of the optical coupling device and the manufacturing method thereof will be described.

In the structure and manufacturing method of the optical coupling device shown in FIG. 11, the optical path between the light emitting and receiving elements 3 and 4 is formed by potting the translucent insulating resin 5 instead of transfer molding. It will be.

[0010]

In recent years, as shown in FIGS. 12 and 13, the light receiving element 4 is provided between the light emitting element 3a and the light receiving element 4 via the translucent insulating resin body 7. An optical coupling device in which a translucent insulating resin body 7 and a light emitting element 3a are sequentially laminated is being considered.

The structure and manufacturing method of the optical coupling device (proposed example 1) shown in FIG.
A light-receiving element 4, a translucent insulating resin body 7, and a light-emitting element 3a are laminated in this order, and these are resin-sealed by transfer molding with a light-shielding insulating resin 6.

Further, the structure of the optical coupling device (proposed example 2) shown in FIG. 13 and the method of manufacturing the same are specifically described on a printed circuit board having a conductor pattern 9 such as a metal electrode on the surface of a substrate 8 such as a glass epoxy substrate. The light receiving element 4, the translucent insulating resin body 7, and the light emitting element 3a are sequentially laminated on the conductor pattern 9, and the resin flow stop frame 10 is mounted on the outer peripheral end of the printed circuit board. The light emitting element 3a, the translucent insulating resin body 7 and the light receiving element 4 are resin-sealed by filling the light shielding insulating resin 6 in the inside 10.

However, the above-described optical coupling device shown in FIGS. 9, 11, 12 and 13 has the transparent insulating resin 5
Alternatively, the light-transmissive insulating resin body 7 and the light-shielding insulating resin 6 are not chemically bonded to each other, and an interface is formed between them. Therefore, the length of the interface becomes the creeping distance between the light emitting elements 3 and 3a and the light receiving element 4, which is extremely short. Then, contaminants and moisture from the outside easily invade the interfaces on these creeping surfaces, and ion conduction occurs due to the contaminants and moisture. This phenomenon is
The shorter the creepage distance, the more likely it is that electrical insulation will fail during long-term operation. Further, the interface between the light-transmissive insulating resin 5 or the light-transmissive insulating resin body 7 and the light-shielding insulating resin 6 may be separated due to temperature change or the like. 14 is a view showing the state, (a) is a vertical cross-sectional view showing a peeled state of the optical coupling device shown in FIGS. 8 and 9, and (b) is a peeled state of the optical coupling device shown in FIG. 11. Is a vertical sectional view showing
FIG. 13C is a vertical cross-sectional view showing the peeled state of the optical coupling device shown in FIG. 12, and FIG. 13D is a vertical cross-sectional view showing the peeled state of the optical coupling device shown in FIG. At this time, since the distance between the light emitting elements 3 and 3a and the light receiving element 4 is short, discharge is likely to occur at the separated interface, and the withstand voltage is extremely reduced.

The withstand voltage is indispensable in an optical coupling device (photocoupler). Therefore, the size of the translucent insulating resin 5 or the translucent insulating resin body 7 cannot be reduced.

Further, in the above-described optical coupling device shown in FIGS. 8 and 9, the light emitting element 3 and the light receiving element 4 are resin-molded by the translucent insulating resin 5 by transfer molding as a manufacturing method thereof. In some cases, the release agent applied to the surface of the molding die adheres to the surface of the light-transmitting insulating resin 5, and the bond with the light-shielding insulating resin 6 that subsequently seals the resin becomes weaker.

In view of the above-mentioned problems, the present invention provides an optical coupling device in which a translucent insulating resin and a light-shielding insulating resin are joined to each other with no interface, and a highly efficient, ultra-compact, low-priced optical coupling device can be obtained. The purpose of the present invention is to provide a manufacturing method of.

[0017]

A method of manufacturing an optical coupling device according to the present invention comprises a light emitting element for converting an electric signal into an optical signal, a light receiving element for converting the optical signal into an electric signal, the light emitting element and a light receiving element. A light-transmitting insulating resin which is provided between the light-emitting element and the light-receiving element and which covers the light-emitting element, the light-receiving element and the light-transmitting insulating resin. In the method of manufacturing an optical coupling device comprising: a step of disposing the light emitting element and the light receiving element so as to be optically coupled to each other through the translucent insulating resin.
A step of performing a modification treatment on the surface of the translucent insulating resin to enhance the reactivity with the light-shielding insulating resin, the light emitting element,
And a step of coating the light receiving element and the translucent insulating resin with the light shielding insulating resin.

The above modification treatment is characterized in that the surface of the translucent insulating resin is subjected to plasma ashing or ultraviolet irradiation in an atmosphere containing oxygen.

The light-transmitting insulating resin and the light-shielding insulating resin are both made of epoxy resin.

[0020]

According to the above structure, the method for manufacturing an optical coupling device of the present invention comprises a step of performing a modification treatment on the surface of the light-transmissive insulating resin to enhance the reactivity with the light-shielding insulating resin. Therefore, the light-transmissive insulating resin and the light-shielding insulating resin are chemically reacted with each other to be integrated, and the interface between the light-transmissive insulating resin and the light-shielding insulating resin can be eliminated.

For example, when the surface of the translucent epoxy resin is subjected to plasma ashing or ultraviolet irradiation in an atmosphere containing oxygen, ester bonds in the epoxy resin molecules,
C—C and C—H bonds of the alkyl group are cleaved, and a new carboxyl group or hydroxyl group is generated. The carboxyl group and the hydroxyl group act as an initiator of the curing reaction with the light-shielding insulating resin to be resin-sealed, and therefore the light-transmitting epoxy resin and the light-shielding insulating resin are combined and integrated as one molecule. , Will be made interfaceless.

Therefore, due to the effect of plasma ashing or ultraviolet irradiation, the light-transmissive epoxy resin and the light-shielding insulating resin are in a combined state, and the light-transmissive epoxy resin and the light-shielding insulating resin are changed due to temperature change or the like. The interface with and is not peeled off, the generation of a gap can be suppressed, and the decrease in withstand voltage can be eliminated.

Further, by using both the light-transmitting insulating resin and the light-shielding insulating resin as an epoxy resin material, the bonding between the two becomes the same kind of bonding, and the chemical bonding between the two resins becomes smoother. , Can be completely integrated.

[0024]

1 is a manufacturing process diagram for explaining a method of manufacturing an optical coupling device according to an embodiment of the present invention.

As shown in FIG. 1D, the optical coupling device manufactured in this embodiment has a GaAs infrared light emitting diode or the like at the tip of individual metal lead frames 1 and 2 made of metal or the like. The light emitting element 3 and the light receiving element 4 such as a phototransistor are separately mounted, and the light emitting element 3 and the light receiving element 4 are arranged so as to be optically coupled to each other. Is sealed with a translucent insulating resin 5 such as an epoxy resin in order to protect the element and improve the optical external quantum efficiency. Further, the outer peripheral portion of the translucent insulating resin 5 is
In order to protect the lead frames 1 and 2 made of metal and to prevent invasion of ambient light, the structure is resin-sealed with a light-shielding insulating resin 6 such as an epoxy resin.

A method of manufacturing the optical coupling device having the structure will be described below with reference to FIG.

First, as shown in FIG. 1A, the light emitting element 3 and the light receiving element 4 are die-bonded to individual metal lead frames 1 and 2 via a silver paste or the like by a normal die-bonding method to emit the light. The element 3 and the light receiving element 4 are arranged so as to face each other so as to be optically coupled.

Next, as shown in FIG. 1 (b), transfer molding is performed with a translucent epoxy resin 5 in a state where both the elements 3 and 4 are arranged facing each other, and an optical path between the light receiving and emitting elements 3 and 4 is obtained. To form. At this time, the release agent applied to the surface of the molding die remains on the surface of the translucent epoxy resin 5.

Then, next, as shown in FIG. 1C, the surface of the transparent epoxy resin 5 is cleaned and activated. As one of the methods, there is a method using plasma ashing, in which a product sealed with a translucent epoxy resin 5 is placed in a plasma container 11 and an electric power is applied in an atmosphere of dry air 0.8 Torr. Plasma is generated at 250 W and plasma ashing treatment is performed for up to 1 hour.

Thereafter, as shown in FIG. 1D, the outer peripheral portion of the translucent epoxy resin 5 is transfer-molded with the light-shielding epoxy resin 6 to obtain a finished product.

As described above, when plasma ashing is performed on the surface of the translucent epoxy resin 5 in an atmosphere containing oxygen, the ester bond in the epoxy resin molecule and the C—C and C—H bonds of the alkyl group are broken. Then, a new carboxyl group or hydroxyl group is generated. Since the carboxyl group and the hydroxyl group act as an initiator of the curing reaction of the light-shielding epoxy resin 6, the light-transmitting epoxy resin 5 and the light-shielding epoxy resin 6 are combined and integrated as one molecule, and there is no interface. Will be realized.

Therefore, due to the effect of the plasma ashing treatment, the translucent epoxy resin 5 and the light-shielding epoxy resin 6 are in a combined state, and the light-transmissive epoxy resin 5 and the light-shielding epoxy resin are changed due to temperature change or the like. The interface with the resin 6 will not be peeled off, the generation of gaps can be suppressed, and the decrease in withstand voltage can be eliminated. According to this example, even if the temperature cycle test of −40 ° C. to 125 ° C. was performed, the breakdown voltage did not decrease.

As a result, the creepage distance can be shortened, and the outer shape of the transparent epoxy resin 5 of the double transfer molded optical coupling device can be reduced.
Compared with the conventional optical coupling device having the same configuration shown in FIG. 7A, the optical coupling device of this embodiment shown in FIG. 7A 'can be made smaller and thinner as a finished product.

Further, in the present embodiment, the translucent insulating resin 5 and the light-shielding insulating resin 6 are both made of epoxy resin, and since they are the same kind of bond, the chemical bond between the two resins 5, 6 is not used. It is done more smoothly and is fully integrated.

FIG. 2 is a manufacturing process diagram for explaining another embodiment of the present invention. Regarding the manufacturing method of this embodiment,
Only points different from the above-described embodiment will be described.

The optical coupling device manufactured in this embodiment has a structure in which an optical path between the light emitting / receiving elements 3 and 4 is formed by potting a transparent insulating resin 5 instead of transfer molding. It consists of

In this embodiment, first, the light emitting element 3 and the light receiving element 4 are arranged to face each other as shown in FIG. 2A, and then the light receiving and emitting elements 3 and 4 are placed as shown in FIG. 2B. The translucent insulating resin 5 is potted between them, and then these are placed in the plasma container 11 as shown in FIG. 2C, and plasma ashing treatment is performed. Then, as shown in FIG. 2D, transfer molding is performed using the light-shielding insulating resin 6 to obtain a finished product.

According to the present embodiment, since the interface between the two resins 5 and 6 is eliminated, the distance between the light emitting element 3 and the light receiving element 4 can be shortened, and the creepage distance can be shortened.
Compared with the conventional optical coupling device having the same structure shown in (b), the optical coupling device of this embodiment shown in FIG. 7 (b ') can be made smaller and thinner as a finished product.

FIG. 3 is a manufacturing process diagram for explaining still another embodiment of the present invention. This embodiment is shown in FIG.
Only points different from the embodiment shown in will be described.

In the optical coupling device manufactured in this embodiment, the light receiving element 4, the translucent insulating resin body 7, and the light emitting element 3a are sequentially laminated on one metal lead frame 2, and these are shielded from the light shielding insulating resin. The structure is resin-sealed by transfer molding of No. 6.

A method of manufacturing the optical coupling device having the above structure will be described below with reference to FIG.

First, as shown in FIG. 3 (a), the light receiving element 4 is die-bonded to one of the metal lead frames 2 through a silver paste or the like by a normal die-bonding method.

Next, as shown in FIG. 3B, a translucent insulating resin body 7 made of an epoxy resin material is mounted on the light receiving surface of the light receiving element 4, and a translucent epoxy adhesive is used. And sticks.

Next, as shown in FIG. 3C, a light emitting element 3a including a backside light emitting diode or the like is mounted on the translucent insulating resin body 7 and fixed by a translucent epoxy adhesive. To do. Here, as shown in FIG. 4, the back surface light emitting diode 3a is configured such that the cathode electrode 12 is not directly under the active layer 13 and light can be efficiently extracted from the back surface side of the element 3a. In the figure, 14 is an n-type semiconductor layer, 15 is a p-type semiconductor layer, and 16 is an anode electrode. It should be noted that the anode and the cathode may have opposite configurations.

In this state, the surface of the light-transmissive insulating resin body 7 is not activated, and even if the light-shielding insulating resin 7 is transfer molded, the light-transmissive insulating resin body 7 and the light-shielding insulating resin 7 are insulated from each other. It will not be in a bonded state with the resin 6.

Therefore, as shown in FIG.
It is placed in the plasma container 11 in the state of (c) and subjected to plasma ashing treatment to activate the surface of the translucent insulating resin body 7. Here, the conditions of the plasma ashing process are the same as those in the embodiment shown in FIG.

After that, as shown in FIG. 3 (e), the portions of the metal lead frames 1 and 2 other than the portions to be the leads for external connection are transfer-molded with the light-shielding insulating resin 6 to complete the products.

According to the present embodiment, the translucent insulating resin body 7 and the light-shielding insulating resin 6 chemically react with each other so that there is no interface between them, so that the translucent insulating resin body 7 has a thickness. 7C, the optical coupling device of the present embodiment shown in FIG. 7C 'can be made smaller as a finished product, as compared with Proposed Example 1 having an equivalent structure shown in FIG. 7C. Can be made thinner.

FIG. 5 is a manufacturing process diagram for explaining still another embodiment of the present invention.

The optical coupling device manufactured in this embodiment is provided on a printed circuit board having a conductor pattern 9 such as a metal electrode on the surface of a substrate 8 such as a glass epoxy substrate, specifically, on the conductor pattern 9. The light receiving element 4, the translucent insulating resin body 7, and the light emitting element 3a are sequentially laminated, and the resin flow stop frame 10 is mounted on the outer peripheral end of the printed circuit board. 6 is filled, so that the light emitting element 3a, the translucent insulating resin body 7, and the light receiving element 4 are resin-sealed.

A method of manufacturing the optical coupling device having the structure will be described below with reference to FIG.

First, as shown in FIG. 5A, a metal electrode 9 made of a glass epoxy base material 8 is formed by double-sided wiring, and a resin flow stop frame 10 made of a glass epoxy material or the like is formed at the outermost peripheral edge of the surface. The light-receiving element 4 is die-bonded to the printed circuit board to which is adhered by a normal die-bonding method via a silver paste or the like.

Next, as shown in FIG. 5B, the translucent insulating resin body 7 made of an epoxy resin material is mounted on the light receiving surface of the light receiving element 4, and the translucent epoxy adhesive is used. And sticks.

Next, as shown in FIG. 5C, a light emitting element 3a including a backside light emitting diode or the like is mounted on the transparent insulating resin body 7 and fixed by a transparent epoxy adhesive. To do. Here, as the backside light emitting diode 3a,
The structure shown in FIG. 4 is used.

In this state, the surface of the light-transmissive insulating resin body 7 is not activated, and even if the light-shielding insulating resin 7 is transfer molded, the light-transmissive insulating resin body 7 and the light-shielding insulating resin 7 are insulated from each other. It will not be in a bonded state with the resin 6.

Therefore, as shown in FIG.
It is placed in the plasma container 11 in the state of (c) and subjected to plasma ashing treatment to activate the surface of the translucent insulating resin body 7. Here, the conditions of the plasma ashing process are the same as those in the embodiment shown in FIG.

Thereafter, as shown in FIG. 5 (e), the light-shielding insulating resin 6 made of a liquid epoxy resin material is cast in the resin flow stop frame 10 by a dispenser or the like so that the light emitting element 3a and the light receiving element 4 are formed. , Resin sealing the translucent insulating resin body 7,
A completed product is obtained by curing the light-shielding insulating resin 6.

FIG. 6 shows a comparison diagram of the number of occurrences of insulation breakdown voltage failure in the temperature cycle test of the optical coupling device with and without plasma ashing of this embodiment.

As is clear from FIG. 6, the breakdown voltage failure is significantly reduced, and the surface activation effect of plasma ashing is effectively imparted.

According to the present embodiment, the translucent insulating resin body 7 and the light-shielding insulating resin 6 chemically react with each other so that no interface is formed between them, so that the thickness of the translucent insulating resin body 7 is increased. 7D, the optical coupling device of the present embodiment shown in FIG. 7D 'can be made smaller as a finished product, as compared with Proposed Example 2 having an equivalent structure shown in FIG. 7D. Can be made thinner.
Specifically, the optical coupling device of FIG. 7 (d ') is shown in FIG.
The thickness of the translucent insulating resin body 7 can be thinned from 500 μm to 250 μm as compared with the size of Proposed Example 2 shown in FIG. 2, and the outer shape is thinned to 1.9 mm as compared with the conventional 2.15 mm. The device was realized. Further, since the thickness of the translucent insulating resin body 7 is reduced by half, the light utilization efficiency is doubled, which leads to the realization of a high performance optical coupling device.

Since the printed circuit board material and the resin flow stop frame 10 are made of a glass epoxy material, not only the space between the translucent insulating resin body 7 and the light shielding insulating resin 6, but also the printed circuit board and the resin. A coupled state can be obtained between the anti-flow frame 10 and the light-shielding insulating resin 6,
It is possible to eliminate the interface.

In the embodiments described above, plasma ashing is used as a method for cleaning and activating the surface of the translucent insulating resin 5 or the translucent insulating resin body 7. Equivalent effects are obtained, and ultraviolet irradiation is performed instead of the plasma ashing, whereby a small-sized optical coupling device is realized for the same reason as that of the plasma ashing.

Further, the plasma ashing and the irradiation with ultraviolet rays have a secondary effect that molecular instability is easily obtained even if there is chemical contamination on the surface of the translucent insulating resin, and stable interface-free is realized. It is possible to

Furthermore, although the epoxy resin is used as the resin material for the transparent insulating resin 5, the transparent insulating resin body 7 and the light blocking insulating resin 6, the present invention is not limited to this, and the transparent insulating resin is not limited thereto. Silicon resin or polyimide resin may be used as 5 and the translucent insulating resin body 7, and polyimide resin may be used as the light shielding insulating resin 6. However, it is desirable that the light-transmissive insulating resin 5 or the light-transmissive insulating resin body 7 and the light-shielding insulating resin 6 are of the same kind of bond, and are epoxy resin-epoxy resin, polyimide resin-polyimide resin. Is good. When a polyimide resin is used as the resin material, the cost is higher than that of an epoxy resin.

[0065]

As described above, according to the method of manufacturing an optical coupling device of the present invention, a step of performing a modification treatment on the surface of the translucent insulating resin to enhance the reactivity with the light shielding insulating resin is performed. Since the structure is provided, the light-transmissive insulating resin and the light-shielding insulating resin form a combined state and are integrated with each other with no interface. As a result, the gap between the two resins that occurs in the temperature cycle test, which was the cause of the decrease in withstand voltage, is eliminated, and not only the outer size of the translucent insulating resin can be reduced, but also the light emitting element and the light receiving element It has become possible to provide a highly efficient, ultra-compact, low-priced optical coupling device that can reduce the distance. In the modification treatment step, a plasma ashing or ultraviolet irradiation step is added between the step of forming an optical path made of a translucent insulating resin between the light emitting and receiving elements and the resin sealing step of a light shielding insulating resin. Just good,
The device is not large and can be easily realized.

Furthermore, by using both the light-transmitting insulating resin and the light-shielding insulating resin as an epoxy resin material, the bonding between the two becomes the same kind of bonding, and the chemical bonding between the two resins becomes smoother. , Fully integrated.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram for explaining a manufacturing method of an optical coupling device according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram for explaining a manufacturing method of an optical coupling device according to another embodiment of the present invention.

FIG. 3 is a manufacturing process diagram for explaining a manufacturing method of an optical coupling device according to still another embodiment of the present invention.

4 is a perspective view showing a specific structure of the light emitting device shown in FIG.

FIG. 5 is a manufacturing process diagram for explaining the manufacturing method of the optical coupling device according to still another embodiment of the present invention.

FIG. 6 is a comparison diagram of the number of occurrences of insulation breakdown voltage defects in a temperature cycle test of an optical coupling device with and without plasma ashing.

FIG. 7 is a diagram showing the comparison of the external sizes of the optical coupling device according to the present invention and the conventional optical coupling device or the proposed example.

FIG. 8 is an external view of a general optical coupling device.

9 is a vertical cross-sectional view of FIG.

10 is a manufacturing process diagram of the optical coupling device shown in FIGS. 8 and 9. FIG.

FIG. 11 is a vertical cross-sectional view showing another general optical coupling device.

FIG. 12 is a vertical sectional view showing a proposed example.

FIG. 13 is a vertical cross-sectional view showing another proposal example.

FIG. 14 is a vertical cross-sectional view showing a peeled state at the resin interface of the optical coupling device of the general example and the proposed example.

[Explanation of symbols]

 1, 2 Metal lead frame 3 Light emitting element 3a Backside light emitting diode (light emitting element) 4 Light receiving element 5 Light-transmissive insulating resin 6 Light-shielding insulating resin 7 Light-transmissive insulating resin body 8 Glass epoxy base material 9 Conductor pattern 10 Resin flow Stop frame 11 Plasma container

Claims (3)

[Claims] 1. A light emitting element for converting an electric signal into an optical signal, a light receiving element for converting the optical signal into an electric signal, and a light emitting element and a light receiving element provided between the light emitting element and the light receiving element. And a light-transmitting insulating resin for electrical insulation and an optical path, and a light-shielding insulating resin that covers the light-emitting element, the light-receiving element, and the light-transmitting insulating resin. A step of arranging the element and the light receiving element so as to be optically coupled to each other with the translucent insulating resin interposed therebetween, and increasing the reactivity with the light shielding insulating resin on the surface of the translucent insulating resin. A method of manufacturing an optical coupling device, comprising: a step of performing a modification treatment; and a step of coating the light emitting element, the light receiving element, and the translucent insulating resin with the light shielding insulating resin. 2. The method for manufacturing an optical coupling device according to claim 1, wherein the modification treatment is performed by plasma ashing or ultraviolet irradiation on the surface of the translucent insulating resin in an atmosphere containing oxygen. 3. The method of manufacturing an optical coupling device according to claim 2, wherein both the light-transmitting insulating resin and the light-shielding insulating resin are made of epoxy resin.