JPH11354830A - Photocoupling semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the emission output efficiency and light transfer efficiency, by forming a conductive reflective film serving as an electrode of a light emitting element on the top of this element, and filling or covering the gap between the light emitting element and light receiving element and the entire or part of a light emitting part of the light emitting element with a light-permeable coating. SOLUTION: A light receiving element 1 on a printed wiring board 9 and a light emitting element 3 having a conductive reflecting film formed thereon are assembled, and a light-permeable coating agent 8 of silicone varnish, etc., is coated on the gap between the lower face of the light emitting element 3 and a light-permeable insulation film 2 and part from the side face of the light emitting element 3 to an effective light receiving part of the light receiving element 1. The light emitting element 3 has a light reflective layer 6 which reflects a light directed to the top face and lies on a light directed to the bottom face, thereby raising the light emission efficiency, and the light-permeable coating 8 is provided in the gap between and around both elements to thereby increase the external quantum efficiency and also functions as a light guide to improve the light transfer efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling semiconductor device, such as a photocoupler, having a light emitting element such as an LED and a light receiving element such as a photodiode arranged face-to-face.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing an example of a conventional optical coupling semiconductor device. In the figure, reference numeral 1 denotes a light receiving element, 3 denotes a light emitting element, which are mounted on die islands of lead frames 16 and 17, respectively, are provided with electrode lead wires by lead wires 13, and have a quantum efficiency on the upper surface of the light emitting element 3. Is coated with a light-transmissive coating agent 8 to increase the temperature.

A light receiving element 1 and a light emitting element 3 mounted on a lead frame are primarily molded with a light transmitting resin 15 in a state where they face each other with a gap therebetween, and a secondary molding is performed with a light shielding resin 10 on the outside thereof. Have been.

[0004] The light emitting element 3 having the above-described structure is used.
Is optically coupled to the light receiving element 1 via the coating agent 8 and the light transmitting resin 15.

[0005]

Since the conventional optical coupling semiconductor device is constructed as described above, the light receiving element and the light emitting element are individually mounted on a lead frame in advance, and the two lead frames are opposed to each other. Then, after fixing at a fixed interval, a complicated operation process of performing primary molding on the outside and then secondary molding on the outside was required.

[0006] Lead wire wiring for leading out the electrodes is made from the opposing surfaces of the light emitting element and the light receiving element. In order to maintain their electrical insulation, the height and arrangement of the lead wires are taken into consideration. The distance between them must be kept as appropriate, which has been an obstacle to increasing the light transmission efficiency.

[0007]

In order to solve the above problems, an optical coupling semiconductor device according to the present invention comprises an insulating substrate provided with external connection terminals and metal wiring, and a light receiving surface fixed on the insulating substrate. A light-receiving element having a light-transmitting insulating film formed thereon, an electrode lead metal wiring for a light-emitting element formed on the light-transmitting insulating film, and conductively mounted and mounted on the electrode lead metal wiring, emitting light on the upper surface. A light-emitting element in which a conductive reflective film also serving as one electrode of the element is formed, and a plurality of bump electrodes are formed on the bottom surface, electrode lead wire wiring of the light-emitting element and the light-receiving element, and the light-emitting element and the light-receiving element A light-transmitting coating agent that filled or covered the gap and the entire or a part of the light-emitting portion of the light-emitting element, and a light-shielding resin formed so as to integrally cover each portion provided on the insulating substrate.

Further, in the above configuration, the device is configured using a lead frame instead of the insulating substrate provided with the external connection terminals and the metal wiring.

A package provided with an external connection terminal and a metal wiring, or a package provided with a lead frame having an end portion as an external connection terminal, and a light-transmitting insulating film fixed on the inner surface of the package and having a light-receiving surface. The formed light receiving element,
An electrode lead metal wiring for a light emitting element formed on the light transmissive insulating film, and a conductive reflection film which also serves as one electrode of the light emitting element is formed on the upper surface, which is placed on and bonded to the electrode lead metal wiring. And a light emitting element having a plurality of bump electrodes formed on a bottom surface, lead wire wiring for leading out the electrodes of the light emitting element and the light receiving element, and a light transmissive resin filling the entire space in the package.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a sectional view of an embodiment according to the first aspect.

In this embodiment, a printed wiring board that can easily form metal wiring on an insulating substrate is used as an apparatus substrate. On the upper surface of the printed wiring board 9, metal wirings 21 and 22 for leading out electrodes are provided, and on the lower surface thereof, external connection terminals 11 on the light receiving side are provided.
And a light-emitting side external connection terminal 12 which is electrically connected through a through hole.

On the upper surface of the printed wiring board 9, a light-transmitting insulating film 2 such as a polyimide film is formed in advance on a light-receiving surface, and a light-receiving element electrode wiring metal wiring 5 is further formed thereon. The element 1 is fixed by an adhesive. In this example, the light receiving element electrode 7 is provided only on the upper surface of the element as shown in the figure. However, in the case of a light receiving element having an electrode on the lower surface of the element, it is fixed using a conductive adhesive.

On the other hand, the light-emitting element 3 has a conductive reflective film 6 such as a gold vapor-deposited film also serving as an electrode on its upper surface, and a light-emitting element 3 on its lower electrode portion.
After the electrodes 4 of the gold bumps are formed in a tripod-like arrangement, they are placed on the metal wiring 5 with the gold bump surfaces facing down, and are bonded by heating.

The metal wires 5 connected to the upper electrode 6 and the lower electrode of the light emitting element 3 are connected to lead wires 13a and 13a, respectively.
b to the metal wiring 22 of the printed wiring board 9 and the electrodes 7 of the light receiving element to the lead wires 14a and 14a, respectively.
b connects to the metal wiring 21.

As described above, after the light receiving element 1 and the light emitting element 3 are further assembled on the printed wiring board 9, the gap between the lower surface of the light emitting element 3 and the light transmitting insulating film 2 and the light emitting element 3 A light transmissive coating agent 8 such as a silicon varnish is filled or applied using a dispenser or the like to a portion from the side surface to the effective light receiving surface portion of the light receiving element 1.

After forming and assembling the above components, the entire upper side of the printed wiring board 9 is molded with a light-shielding resin by transfer molding to complete the device. In order to mount the present device, for example, a method is used in which the device is mounted on a counterpart substrate with solder balls interposed therebetween and heated and bonded.

As described above, since the light reflecting film 6 is provided on the upper surface of the light emitting element 3, of the light generated from inside the light emitting element 3, the light going to the upper surface is reflected downward in the element by the reflecting film. The light is superimposed on the light traveling in the bottom direction to improve the light output efficiency.

As described above, the light-transmitting coating agent 8 is provided not only at the gap between the two devices but also around the side from the side to the bottom. This portion has the effect of increasing the external quantum efficiency of the light-emitting device 3. At the same time, it functions as a light waveguide and greatly contributes to increasing light transmission efficiency.

Although the embodiment of FIG. 1 has been described above, the basic structure of the present invention in which a light-transmitting insulating film is provided on a light-receiving element and a light-emitting element is provided thereon via a bump electrode, is as follows.
Various embodiments are possible.

FIG. 2 is a sectional view of an embodiment according to the second aspect. In the present embodiment, lead frames 16 and 17 are used instead of the printed wiring board 9 in the embodiment of FIG.

On the lead frames 16 and 17, the light receiving element 1, the light emitting element 3 and the like are incorporated in the same form as described above.
Lead frame 1 serving as external connection terminals on the light receiving side and light emitting side
Except for the end portions 6 and 17, the whole is molded with the light-shielding resin 10.

FIGS. 3 and 4 are sectional views of an embodiment corresponding to claim 3, respectively, showing the apparatus in a face-down state. In these embodiments, a package is used in a portion corresponding to the light-shielding resin mold in the above example.

In the embodiment shown in FIG. 3, the light receiving element 1 and the light emitting element 3 are fixed on the die island of the ceramic package 18 provided with the lead electrodes 19 in the same manner as described above. The inside is filled with a light transmissive resin 15. The light transmitting resin 15 is the light transmitting coating agent 8 used in the embodiment of FIGS.
Functions as a light waveguide in the same manner as described above.

As the material of the light-transmitting resin 15, the light-transmitting coating agent used in the above-described embodiment can be used, but a flexible material serving as a buffer for thermal expansion is suitable.

Although the package is not provided with a lid in the present apparatus, when the package is mounted on the printed wiring board 9 or the like, the package is turned upside down as shown in FIG. Thus, external light is blocked. The electrodes are connected to the wiring board by directly soldering the ends of the lead electrodes 19.

FIG. 4 shows an embodiment in which a package 20 with a lead frame is used. The internal configuration and mounting method are exactly the same as in the embodiment of FIG.

FIG. 5 is a perspective view of the internal structure of the fourth embodiment. As in the case of the embodiment shown in FIG. 2, each part is provided on the lead frames 16 and 17 and the outside is molded with a light-shielding resin 10, but as shown in FIG. Are provided with three light emitting elements, and lead wires are wired to external connection terminals (lead frame terminals) independent of each electrode.

As described above, since a single light receiving element and a plurality of light emitting elements are combined and independent external connection terminals are provided, the present device can be used as a logical OR circuit.

[0029]

As described above, in the optical coupling semiconductor device of the present invention, the light receiving element having the light transmitting insulating film formed on the light receiving surface is fixed on the insulating substrate or in the lead frame or package. Since the electrode lead metal wiring for the light emitting element is formed on the conductive insulating film, and the light emitting element having a plurality of bump electrodes formed on the bottom surface is placed on the electrode lead metal wiring and electrically conductively bonded, The complicated procedure of assembling both elements into separate lead frames and then fixing and molding each one is unnecessary, and the assembly work of arranging the light emitting elements on the light receiving elements is a continuous operation by stacking. Will be able to do it.

Further, the light-emitting element and the light-receiving element are insulated by a light-transmitting insulating film, and the lead wire wiring from the electrode can be provided in the gap between the two elements, so that the gap can be set narrower. In addition, it is possible to realize highly efficient optical coupling as compared with the conventional structure, and at the same time, it is possible to reduce the size.

Further, the light reflecting film provided on the light emitting element and the light transmitting coating agent provided on the side surface thereof also greatly contribute to the high efficiency of optical coupling.

Further, by providing a plurality of light emitting elements on the same light receiving element, a logical OR circuit using a plurality of light emitting element inputs can be realized as a compact device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an embodiment corresponding to claim 1 of the optical coupling semiconductor device of the present invention.

FIG. 2 is a sectional view of an embodiment according to the second aspect of the present invention.

FIG. 3 is a cross-sectional view of an embodiment also corresponding to claim 3;

FIG. 4 is a sectional view of another embodiment, also corresponding to claim 3;

FIG. 5 is a perspective view of an internal structure according to an embodiment of the present invention.

FIG. 6 is a sectional view of an example of a conventional optical coupling semiconductor device.

[Explanation of symbols]

1: light receiving element, 2: light transmitting insulating film, 3: light emitting element,
4: bump electrode, 5: metal wiring, 6: conductive reflection film,
7: light receiving element electrode, 8: light transmitting coding agent, 9:
Printed wiring board, 10: light shielding resin, 11: light receiving side external connection terminal, 12: light emitting side external connection terminal, 13: light emitting part lead wire, 14: light receiving part lead wire, 15: light transmitting resin, 16: light receiving Side lead frame, 17: light emitting side lead frame, 18: ceramic package, 19: lead electrode, 20: package with lead frame, 2
1, 22: metal wiring.

Claims (4)

[Claims] An optically coupled semiconductor device comprising a light emitting element and a light receiving element arranged face-to-face, an insulating substrate provided with external connection terminals and metal wiring, and a light transmitting surface fixed to the insulating substrate and having a light transmitting property on the light receiving surface. A light-receiving element on which an insulating film is formed, and an electrode lead metal wiring for a light-emitting element formed on the light-transmitting insulating film,
A light emitting element mounted on the electrode lead metal wiring and electrically conductively bonded, a conductive reflection film serving also as one electrode of the light emitting element is formed on the upper surface, and a plurality of bump electrodes are formed on the bottom surface; Element electrode lead wire wiring,
A light-transmitting coating agent that fills or covers the light-emitting element, the gap between the light-receiving elements, and the entire or a part of the light-emitting portion of the light-emitting element, and a light-shielding resin molded so as to integrally cover each part provided on the insulating substrate. And an optically coupled semiconductor device. 2. The optical coupling semiconductor device according to claim 1, wherein the insulating substrate provided with the external connection terminals and the metal wiring is replaced with a lead frame. 3. An optical coupling semiconductor device comprising a light emitting element and a light receiving element arranged face-to-face, wherein a package provided with an external connection terminal and a metal wiring or a package provided with a lead frame having an end portion as an external connection terminal is provided. A light-receiving element having a light-transmitting insulating film formed on a light-receiving surface, which is fixed to an inner surface of the package, an electrode lead metal wiring for a light-emitting element formed on the light-transmitting insulating film, and A light-emitting element having a conductive reflection film formed on the upper surface and also serving as one electrode of the light-emitting element, and a plurality of bump electrodes formed on the bottom surface, and a lead wire for leading out the electrodes of the light-emitting element and the light-receiving element. An optical coupling semiconductor device, comprising: a wiring; and a light transmissive resin filled in a space in the package. 4. The light-emitting device according to claim 1, wherein a plurality of light-emitting elements are provided on the same light-receiving element, and a metal wiring, an electrode lead wire and an external connection terminal are provided for each light-emitting element. Optical coupling semiconductor device.