JPS5924555B2 - Hikariketsugohandoutaisouchinojitsusohouhou - Google Patents

Description

[Detailed description of the invention] Fields of use of C light] The present invention relates to an optically coupled semiconductor device.

. BACKGROUND OF THE INVENTION Conventionally, there have been many problems in mounting methods for light-emitting elements and light-receiving elements, and various mounting methods have been attempted.

Among these, setting the distance between the light emitting element and the light receiving element is one of the biggest problems since it is necessary to optically couple the light emitting element and the light receiving element efficiently. Typical methods include interposing a transparent insulator such as glass between the light emitting element and the light receiving element, or filling the space with transparent resin, as shown in Japanese Patent Publication No. 46-11137. However, it has drawbacks such as complicated assembly operations, high cost, and insufficient optical coupling efficiency due to the gap between the light emitting element and the light receiving element.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an optically coupled semiconductor device that increases the efficiency of optical coupling between a light emitting element and a light receiving element and is easy to assemble.

[Summary of the invention]

The present invention makes the light emitting element and the light receiving element different in size, uses a face-down bonding method using solder balls for the electrodes, and provides a storage hole in the ceramic substrate with a size that accommodates the smaller element. The smaller element is housed in the housing hole, and the other element is placed on the substrate so as to cover the element in the housing hole, and the pixel element is connected to the substrate by face-down bonding. Features.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optically coupled semiconductor device according to the present invention will be described below.

FIG. 1 shows the state before bonding, and FIG. 2 shows the state after bonding is completed.

In FIG. 1, numeral 1 denotes a multilayer ceramic substrate, which is composed of a first ceramic sheet IA and a second ceramic sheet IB. 2A is the first wiring conductor, 2B is the second wiring conductor, 3
A and 3B are glass dams, 4A and 4B are bonding pads, 5 is a storage hole drilled in the second ceramic sheet IB, and the smaller of the elements 6 and 1 described below (in this example, the light emitting element) 6) It is large enough to store.

6 is a light emitting element, 1 is a light receiving element, and ball-shaped solder electrodes 8 and 9 are formed on both of them.

The light emitting element 6 is housed in the housing hole 5 with the solder electrode 8 in contact with the punch interpad 4A.

The light receiving element 7 is placed on the bonding pad 4B with the solder electrode 9 aligned so as to cover the light emitting element 6 from above. For both pixel elements, the solder electrode and bonding pad are usually temporarily attached with a small pressure.

10 indicates the gap between the light emitting element and the light receiving element after this temporary attachment.

FIG. 2 shows a state in which the connection of the pixel elements 6 and 7 is completed by heating, and 11 and 12 are the completed connection parts. After the solder is melted, the gap 10 shown in FIG. 1 disappears as shown by reference numeral 13, and the pixel elements are brought into close contact. This adhesion effect depends on the amount of solder at the connection part, that is, the sum of the amount of solder on the element and the amount of solder on the bonding pad, the electrode dimension on the element side (usually the diameter of a circle), the dimension on the substrate side, the element weight, etc. side and light receiving element 7
This is done by changing the side. In short, by setting the height change H2 of the light-receiving element when the solder melts larger than the height h1 of the light-emitting element alone when the solder melts (Fig. 1) so as to cancel out the gap 10, the pixel elements can be brought into close contact. can be done. At this time, even if the temporary attachment position of the pixel element is slightly deviated or bent, half-time melting allows the pixel element to be attached in parallel in a position where the forces are balanced. [Effects of Light] As explained above, according to the present invention, a storage hole for accommodating a smaller element, such as a light emitting element, is provided in a ceramic vine substrate made of a first ceramic sheet and a second ceramic sheet, and a light emitting element is formed. The element is accommodated in this storage hole, and the light receiving element is placed on the substrate so as to cover the light emitting element, and the pixel element is connected by face down bonding using solder, so assembly is easy and quick. The project has been completed and the economic effects are significant.

In addition, if the dimensions and amount of solder are different between the connecting parts of the light-emitting element and the light-receiving element, and the light-emitting element and the light-receiving element are connected after the solder melts, and the light-emitting element and the light-receiving element are connected so that there is no gap at all, the light of the pixel element can be The coupling efficiency is extremely good.

Although the illustrated embodiment shows an example in which the light emitting element is small and the light receiving element is large and attached to the substrate, it goes without saying that the reverse may be used.

[Brief explanation of the drawing]

The drawings all show one embodiment of the optically coupled semiconductor device according to the present invention, and FIG. 1 is a sectional view of a portion before assembly, and FIG. 2 is a sectional view after assembly is completed.

Claims (1)

[Claims] 1. An optically coupled semiconductor device in which a light-emitting element and a light-receiving element of different sizes are mounted on a substrate, in which a storage hole is formed in the substrate with a size to accommodate the smaller element, and the light-emitting element or the light-receiving element is mounted on a substrate. The smaller of the two elements is housed in the housing hole, and the other element is placed on the board so as to cover the element housed in the housing hole, and both the elements are connected to the board by face-down bonding. 1. An optically coupled semiconductor device comprising: