JPH05327004A - Semiconductor photocoupler - Google Patents

Abstract

PURPOSE:To provide a photocoupler of uniform quality, whose assembly is simplified, while improving the isolation between its primary and secondary sides and preventing variations of device characteristics. CONSTITUTION:A photodiode 3 is bonded to an island 9 of the lead frame 11 on the primary side, and electrical connections are applied. After the photodiode is potted in transparent silicon resin 4, an insulating film 6 is mounted on a stopper 13 of the lead frame. Similarly, a photodetector 2 is bonded to the lead frame on the secondary side in such a manner that the photodiode and photodetector are opposed, and then the insulating films on the primary and secondary sides are joined by transparent silicon resin 8. Photocouplers thus produced have uniform quality, while the manufacturing process is simplified. If the insulating films are bent into an L shape, the creepage distance between the primary and secondary sides is increased, thus increasing the isolation withstand voltage between them. The insulating film on the secondary side is coated with conductive material and connected to a positive or negative potential so that device characteristics may be stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optically coupled semiconductor device, and more particularly to an optically coupled semiconductor device having a structure of optically coupling via an insulating film.

[0002]

2. Description of the Related Art As shown in FIG. 4, an optical coupling element, which is an example of a conventional optical coupling semiconductor device, includes a light emitting diode 3 and
A light receiving element 2 having a phototransistor or a photodiode which receives light to generate a photoelectromotive force on the element surface, a primary side transparent silicone resin 4 which covers the light emitting diode 3, and It had the secondary transparent silicone resin 5 and the insulating film 19 inserted at the boundary between the primary transparent silicone resin 4 and the secondary transparent silicone resin 5.

Next, the operation of this optically coupled semiconductor device will be described. When an input signal is input to the primary side (input side) of the optically coupled semiconductor device, the light emitting diode 3 emits light, and this light is transmitted through the primary side transparent silicon resin 4, the insulating film 19, and the secondary side transparent silicon resin 5. Street, light receiving element 2
To generate a photoelectromotive force, and use the generated photoelectromotive force as an output of the optically coupled semiconductor device to connect a transistor or a MO connected to the secondary side (output side) of the optically coupled semiconductor device.
It controlled electronic parts such as SFET.

Here, the insulating film 19 disposed between the primary side transparent silicone resin 4 and the secondary side transparent silicone resin 5 is heated by the transparent silicone resins 4 and 5 and the mold resin 20 of the optically coupled semiconductor device. In order to prevent the separation withstand voltage between the primary and secondary from decreasing due to the gap generated at the interface between the transparent silicone resin 4, 5 and the molding resin 20 due to the difference in expansion coefficient, the creepage distance between the primary and secondary is increased. It was used for the purpose of increasing the breakdown voltage.

Next, a method of manufacturing the optically coupled semiconductor device will be described. Island part 9 of the primary side lead frame 11
Mount the light emitting diode 3 on the bonding wire 1
5, the light receiving element 2 is mounted on the island portion 10 of the secondary side lead frame 12, and the bonding wire 16
Wire with. Next, the primary side transparent silicone resin 4 was potted so as to cover the light emitting diode 3, and the secondary side transparent silicone resin 5 was potted so as to cover the light receiving element 2. Here, before the primary side transparent silicone resin 4 and the secondary side transparent silicone resin 5 are cured, the insulating film 19
The primary side lead frame 11 and the secondary side lead frame 1
It is sandwiched between the transparent silicon resins 4 and 5 potted in 2, and the facing silicone between the primary side lead frame 11 and the secondary side lead frame 12 is adjusted and fixed. Resin 20
The whole was sealed with etc.

[0006]

In this conventional optical coupling semiconductor device, the transparent silicon resin is potted to the light emitting diode and the light receiving element, and the transparent silicon resin is cured after the insulating film is sandwiched by the transparent silicon resin. Therefore, depending on the viscosity and amount of the transparent silicone resin, the transparent silicone resin wraps around the insulation film and lead frame,
There is a problem in that the shape of the transparent silicon resin that serves as the optical path varies, and the optical coupling efficiency characteristics of the optical coupling semiconductor device also vary.

Further, in order to cure the transparent silicon resin while holding the insulating film with transparent silicon, the position of the insulating film shifts due to the surface tension of the transparent silicon resin, and wiring is made to internal elements such as light emitting diodes and light receiving elements. There is also a problem that the separation withstand voltage between the primary and the secondary is lowered due to the contact with the existing bonding wire.

Further, when a high electric field is generated in the optically coupled semiconductor device due to a load condition connected to the secondary side or the like, the element characteristics in the optically coupled semiconductor device are changed due to the influence of the high electric field. There was also a problem.

[0009]

According to another aspect of the present invention, there is provided an optically coupled semiconductor device in which a primary side lead frame and a secondary side lead frame retain the shapes of a primary side transparent silicone resin and a secondary side transparent silicone resin, respectively. A lead frame stopper for mounting the side insulating film and the secondary side insulating film is provided.

Further, a conductive coating is applied to the secondary side insulating film, and the secondary side insulating film is connected to a positive potential or a negative potential on the secondary side.

Further, the shape of the primary side or secondary side insulating film or the primary side and secondary side insulating films is L-shaped.

[0012]

By providing the stopper portions for holding the shape of the transparent silicon resin on the primary side and secondary side lead frames, the shape of the transparent silicon resin which is the optical path is stabilized, and the optical coupling efficiency of the optical coupling semiconductor device is improved. This has the effect of reducing variations in characteristics.

Further, the primary side and the secondary side lead frames are provided with stoppers, and the primary side and the secondary side insulating films are mounted on the stoppers so that the insulating film comes into contact with the light emitting diode, the light receiving element and the like. There is also an effect that the separation withstand voltage between the secondary parts will not decrease.

Further, by mounting and fixing the primary side and secondary side insulating films on the primary side and secondary side lead frames respectively, and then connecting the primary side and secondary side lead frames, the assembly becomes easy. It also has the effect of improving mass productivity.

Further, by providing the insulating film with a conductive coat, when a high electric field is generated inside the optically coupled semiconductor device, the electric field is mitigated by the shield, and the characteristic variation of the element in the optically coupled semiconductor device is prevented. is there.

Further, by making the insulating film L-shaped, the creeping distance between the primary and the secondary is increased, and the isolation breakdown voltage between the primary and the secondary is also improved.

[0017]

The present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of an embodiment of the optically coupled semiconductor device of the present invention.

The light emitting diode 3 is die-bonded to the island portion 9 of the primary side lead frame 11,
The primary side insulating film 6 is mounted on the stopper part 13 of the lead frame, and the primary side transparent silicon resin 4 surrounds the light emitting diode 3 and the island part 9 of the lead frame, the stopper part 13 of the lead frame and the primary side insulation It is potted between the films 6.

Further, a light receiving element 2 for generating a photoelectromotive force by receiving light from a phototransistor or a photodiode is die-bonded to the island portion 10 of the secondary side leadframe 12, and a stopper portion of the leadframe is formed. The secondary side insulating film 7 is mounted on 14 and the secondary side transparent silicon resin 5 surrounds the light receiving element 2 and the secondary side transparent silicon resin 5 is formed on the island portion 10 of the lead frame.
And between the stopper portion 14 of the lead frame and the secondary side insulating film 7.

FIG. 2 is a perspective view of the secondary side lead frame 12 of such an optical coupling semiconductor device, which shows a stopper portion 14 of the lead frame and an island portion 10 of the lead frame.
Is a part of the secondary lead frame 12. The shape of the primary side lead frame 11 is also the same as that of the secondary side lead frame 12.

The primary side lead frame 11 and the secondary side lead frame 12 are arranged so that the light emitting diode 3 and the light receiving element 2 face each other. Here, the primary side insulating film 6 and the secondary side insulating film 7 are made of transparent gel silicone resin 8
The optical path between the light emitting diode 3 and the light receiving element 2 is joined from the side of the light emitting diode 3 to the primary side transparent silicone resin 4, the primary side insulating film 6, the transparent gel silicone resin 8, and the secondary side insulating film 7. The secondary side transparent silicone resin 5 is formed in this order.

The lead frame stopper 13,
Since the shapes of the transparent silicone resins 4 and 5 are corrected by 14, the cross-sectional area of the optical passage can be controlled by the stopper portions 13 and 14 of the lead frame.

Next, a manufacturing method of an embodiment of the optically coupled semiconductor device of the present invention will be described. Primary side lead frame 1
After mounting the light emitting diode 3 on the island portion 9 of No. 1 and wiring with the bonding wire 15, the primary side insulating film 6 is mounted on the stopper portion 13 of the primary side lead frame 11 so as to surround the light emitting diode 3 and the primary side is transparent. After the silicon resin 4 is potted between the island portion 9 of the primary side lead frame and the stopper portion 13 of the primary side lead frame and the primary side insulating film 6 is mounted on the stopper portion 13 of the primary side lead frame 11, the primary side transparent The silicone resin 4 is hardened. Similarly, the light receiving element 2 is mounted on the island portion 10 of the secondary side lead frame 12 and is wired by the bonding wire 16, and the secondary side transparent silicon resin 5 is attached to the secondary side lead frame so as to surround the light receiving element 2. After potting between the island portion 10 and the stopper portion 14 of the secondary side lead frame and mounting the secondary side insulating film 7 on the stopper portion 14 of the secondary side lead frame, the secondary side transparent silicon resin 5 is attached. Let it harden.

At this time, the stopper portion of each lead frame has an action of preventing the primary and secondary side transparent silicone resin from getting around along the end face of the lead frame and deforming the shape during curing. Further, by mounting the primary side and secondary side insulating films on the stopper portions of each lead frame, the position of the insulating film is determined from the shape of each lead frame. From this, by controlling the shape of each lead frame, it is possible to prevent the insulating film from contacting the bonding wires that are wired to the elements mounted on the islands of each lead frame. Has become.

Next, after the respective transparent silicone resins 4 and 5 are sufficiently cured, the primary side insulating film 6 mounted on the stopper portion 13 of the primary side lead frame so that the light emitting diode 3 and the light receiving element 2 face each other. The transparent gel silicon resin 8 is adhered and bonded to the secondary insulating film 7 mounted on the stopper portion 14 of the secondary lead frame, and then the transparent gel silicon resin 8 is cured. Seal.

Here, the opposing gaps between the light emitting diode and the light receiving element are the respective lead frames because the primary and secondary side lead frames are joined by the transparent gel silicon resin using the primary and secondary side insulating films. Shape, the thickness of the insulating film, and the thickness of the transparent gel silicone resin.

FIG. 3 is a vertical sectional view of a second embodiment of the optically coupled semiconductor device of the present invention.

In the optically coupled semiconductor device described in Example 1, the primary insulating film is the L-shaped primary side insulating film 17 and the secondary side insulating film is the L-shaped secondary side insulating film with a conductive coat 18. Further, in the L-shaped insulating film with a secondary side conductive coat, only the light receiving element side is subjected to a conductive coat treatment, and the conductive coat surface is grounded to a positive potential or a negative potential on the secondary side (load side). The other parts are the same as in the first embodiment.

In this embodiment, since the insulating film is L-shaped, the creepage distance between the primary and the secondary becomes long, and the isolation breakdown voltage between the primary and the secondary is improved. Even if a high electric field due to the load condition connected to the optical coupling element occurs in the optical coupling element, a conductive coating is applied to the light receiving element side of the secondary side insulating film, and this is set to a positive potential or a negative potential. Therefore, the high electric field generated on the surface of the light receiving element can be blocked by the surface of the conductive coat, and the generation of the high electric field on the surface of the light receiving element is mitigated.

[0030]

As described above, according to the present invention, by providing the stopper portions on the primary side and secondary side lead frames in the optically coupled semiconductor device, the shape of the transparent silicon resin serving as the optical path is maintained and the optical path is disconnected. The area is determined by the shape of the stopper portion, which has the effect of making the optical coupling efficiency in the optical coupling semiconductor device uniform.

Further, by mounting the insulating film on the stopper portion of the lead frame, the distance between the insulating film and the element mounted on the island portion of the lead frame and the bonding wire or the like wired to the element is fixed, and There is also an effect that there is no possibility that the element and the bonding wire or the like wired to the element will come into contact with each other.

Further, by assembling the primary side lead frame and the secondary side lead frame after completing the steps of curing the transparent silicon resin in each of the primary side lead frame and the secondary side lead frame, an assembling process of the optical coupling semiconductor device is performed. It also has the effect of being simplified.

Further, by making the insulating film L-shaped, the creeping distance between the primary and the secondary is increased, and the isolation breakdown voltage between the primary and the secondary is improved.

Further, by providing a conductive coating on the secondary side insulating film and connecting it to a positive potential or a negative potential on the secondary side, the optically coupled semiconductor device depending on load conditions connected to the secondary side (load side). When a high electric field is generated in the inside, the high electric field is blocked by the surface of the conductive coat, so that the characteristic variation of the element mounted on the secondary side lead frame can be prevented.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an optically coupled semiconductor device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a lead frame of an optically coupled semiconductor device according to an embodiment of the present invention.

FIG. 3 is a vertical sectional view of an optically coupled semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of a conventional optically coupled semiconductor device.

[Explanation of symbols]

 2 Light receiving element 3 Light emitting diode 4 Primary side transparent silicone resin 5 Secondary side transparent silicone resin 6 Primary side insulating film 7 Secondary side insulating film 8 Transparent gel silicone resin 9/10 Lead frame island 11 Primary side lead frame 12 Secondary Side lead frame 13/14 Lead frame stopper 15/16 Bonding wire 17 L-shaped primary side insulating film 18 L-shaped secondary side Insulating film with conductive coat 19 Insulating film

Claims (3)

[Claims] 1. An optical coupling semiconductor device having at least one pair of a light emitting diode which emits light in response to an input of an input signal and a light receiving element which receives light from the light emitting diode and generates a photoelectromotive force. A side lead frame and a secondary side lead frame for mounting the light receiving element are provided with stoppers, and a primary side insulating film is adhered to the stoppers of the primary side lead frame, and a secondary side lead frame is provided with a stopper. An optical coupling semiconductor device, characterized in that a secondary insulating film is adhered, and the primary insulating film and the secondary insulating film are joined with a transparent resin or an adhesive. 2. The optically coupled semiconductor device according to claim 1, wherein the secondary side insulating film is provided with a conductive coating, and the secondary side insulating film is connected to a positive potential or a negative potential on the secondary side. Optically coupled semiconductor device. 3. The optically coupled semiconductor device according to claim 1 or 2, wherein the primary side insulating film or the secondary side insulating film, or the primary side insulating film and the secondary side insulating film have an L-shaped shape. An optically coupled semiconductor device characterized by the above.