JPS59136953A - Composite element - Google Patents

Abstract

PURPOSE:To reduce strain-force applied to each element even when size is enlarged, and to apply strain-force uniformly to the elements by forming spaces not communicated with the surfaces of the elements and a conductor in a resin layer. CONSTITUTION:Spaces 12 are formed in regions, in which there is no element 4, 5 and common wiring conductor 3 or drawing conductor 8, through resin shells 11, and connecting sections for a buried resin 10 are reduced substantially. Consequently, a range of the resin 10 applying strain-force to the elements 5 is limited to not the whole resin but a region of (A) substantially, and strain- force is reduced. Strain-force applied to the elements can be equalized symmetrically because the shapes of the buried resins 10 surrounding each element 4, 5 can be brought close to a symmetry by properly varying the shape of a space section in a resin layer by adjusting the shape of a vessel 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite element in which a plurality of circuit elements are internally assembled and wired and sealed with resin.

In such composite devices, multiple semiconductor device chips such as thyristors and diodes are mounted on a substrate made of metal or ceramic, and these semiconductor devices are equipped with electrodes that are connected in common or electrodes that can be taken out individually, and are protected in advance. The resin is directly molded into a single container without using a container or the like. This composite element includes a plurality of semiconductor elements, and is desired to have reliability equal to or higher than that of a single semiconductor element.

FIG. 1 shows an example of this type of composite element, in which element chips 4 and 5 are fixed by a lower electrode 6 to a common wiring 3 on an insulating plate 2 bonded to a cooling plate 1 made of metal, and an upper electrode 7 and the wiring 3 are connected to a lead-out conductor 8 whose end becomes an external terminal. An embedding resin 10 is filled in an internal space formed by the cooling plate 1 and the container outer wall 9 surrounding each element. However, such a composite element has the following drawbacks.

(1) As the size of the composite element increases and the number of elements increases, the amount of resin filled increases, and as a result, the mechanical strain applied to the element increases due to expansion and contraction of the resin during curing. , impairing the reliability of the device.

(2) The electrode wiring between elements becomes complicated, and the
Thermal and mechanical strain forces applied through the resin become uneven locally, lowering the yield rate and reliability of the composite element.

For this reason, it has conventionally been impossible to construct a large-capacity composite element including two or more large-sized elements, such as a 20ysm x 20πm square.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a highly reliable composite device including one for large capacity.

The purpose of this is to fix multiple circuit elements on one substrate, and to seal the parts of each element and the conductor connected to them with a resin layer, except for the external terminals. This is achieved by providing a space that does not communicate with the surface of the conductor.

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, parts common to those in FIG. 1 are given the same reference numerals. In this composite element, a space 12 is provided through a resin shell 11 in an area where the elements 4 and 5 and the common wiring conductor 3 or the lead-out conductor 8 are not present, where the resin 10 for embedding is filled in FIG. Therefore, the connecting portion of the embedding resin 10 is substantially reduced. As a result, for example, the resin 10 exerts a strain on the element 5 in FIG.
The range of is not the entire resin, but is substantially limited to the area ζ of A. Therefore, the strain force applied to each element is reduced. In addition, the shape of the space in the resin layer is appropriately changed by adjusting the shape of the container 9, so that the shape of the embedded resin 10 surrounding each element 4, 5 is made symmetrical or close to symmetrical. Therefore, the strain force applied to the element can be made symmetrical, that is, uniform.

FIGS. 3(a) and 3(b) show an example of a method of forming such a space according to the present invention, in which a space 12 is formed on the outer wall 9 of the container.
This is done by bonding the portions 13 having the above and injecting the resin 10 into the other portions 14. Figure 4 (a), (b
).

(C) shows another method, a hollow resin shell 1
5 into the container 2 and inject the resin 10. It is preferable that the resin shell 15 and the resin shell 11 in FIG. In the case of a composite element, it is preferable that the number is 5 or more. However, in order to prevent the influence of moisture, it is desirable to fill the space provided by the invention with dry air. In that case, it is desirable that the open space 12 shown in FIG. 2 or 3 be sealed with a lid after the gas therein is replaced with dry air.

As described above, the present invention creates a space by removing the embedding resin in the parts of the composite element where the elements and internal wiring conductors are not present at a position lower than the embedding surface. Even if the overall size of the composite element increases due to the increase in the number of elements, the strain force applied to each element should be as small as a composite element with small dimensions, and be applied uniformly to the element. This improves the reliability of the composite element.Furthermore, since part of the embedded resin is replaced with gas, the additional effect of reducing the weight of the composite element is achieved, making it possible to create a large-capacity composite element. The effect is particularly large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional composite element, and FIG. 2 is a sectional view of a composite element according to an embodiment of the present invention. 1...Cooling plate, 2...Insulating plate, 3...Common wiring, 4,5
・Element chip, 8 ・Output conductor, 9 ・Container, 1
0...embedding resin, 12...space.

Claims (1)

[Claims] 1) In a circuit board in which multiple circuit elements are fixed on one substrate, and the parts of each element and the conductor connected to it except for the external terminal parts are sealed with a resin layer, the elements and conductors are inside the resin layer. A composite element characterized by having a space that does not lead to.