JPS6292344A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the cracking of a semiconductor element by making solid body fillers contain near the semiconductor element and hollow body fillers contain into a region separate from the semiconductor element in large quantities respectively. CONSTITUTION:A semiconductor element 1 is placed onto a radiator plate 2, and the periphery is sealed with an insulating resin. In this case, a section in the vicinity of the element 1 is formed by a region 8 containing a large quantity of solid body fillers, and a region separate from the element 1 is shaped by a region 9 including a large quantity of hollow body fillers. The region 8 and the region 9 are formed by the difference of the specific gravity of the hollow body fillers and the solid body fillers. Accordingly, the cracking of the element 1 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a semiconductor device, and more particularly to a sealing structure for a semiconductor element using resin.

[Background of the invention]

In conventional resin-sealed semiconductor devices, Japanese Patent Application Laid-open No. 58
As shown in Japanese Patent No. 184745, a solid filler such as silica is added to a resin to lower the coefficient of thermal expansion of the resin, and a semiconductor element (hereinafter abbreviated as a semiconductor chip) is heated by the difference in thermal expansion. The semiconductor chip was prevented from being destroyed by applying as little stress as possible.

However, as the amount of solid filler added increases, the thermal expansion coefficient of the resin decreases, but on the other hand, the viscosity of the resin before sealing and curing increases, making the resin sealing work difficult, and the elastic modulus of the resin decreases. , which increased due to the inclusion of solid filler, making it impossible to reduce thermal stress sufficiently.

[Purpose of the invention]

An object of the present invention is to provide a resin-sealed semiconductor device that does not cause cracking of the semiconductor chip by reducing the thermal stress of the resin and is easy to manufacture.

[Summary of the invention]

The present invention is characterized in that a hollow filler is added to the sealing resin, and by utilizing the floating effect of the hollow filler, the hollow filler is moved to the upper part of the area occupied by the hollow filler. The goal is to focus on

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows that solid filler and hollow filler are added to protect the semiconductor chip that operates as a triac, and to lower the elasticity and expansion rate of the sealing resin. , hollow body filler 36voQ
γ,) shows a heat sink insulated semiconductor device using a sealed sealing resin.

A semiconductor chip 1 is mounted on a heat sink 2 made of Fe or Cu with a ceramic plate 3 interposed therebetween.

The semiconductor chip 1 is connected to external leads 5 through internal leads 4. The resin case 6 is bonded and fixed to the heat sink 2, and a resin injection lower is provided on the upper surface of the case. When a resin such as epoxy containing a hollow filler and a solid filler is injected from this injection lower and cured by heating, due to the difference in specific gravity between the hollow filler and the solid filler, as shown in Figure 1, It is divided into a region 8 containing a large amount of solid filler and a region 9 containing a large amount of hollow filler.

If the longitudinal elastic modulus of the resin is ER1 and the linear expansion coefficient difference between the resin and the component material inside the resin is ΔαR, then the resin is 0.

The internal thermal stress P is expressed as PgΔαR−ER.

As shown in the figure, when the thickness of the resin is h, a bending moment of stress M=P×h due to thermal contraction of the resin acts on the parts inside the resin. In other words, using a hollow body filler,
It has been found that even if the coefficient of linear expansion of the resin can be increased, it is not possible to sufficiently reduce the internal stress due to the effect of the thickness of the resin. Therefore, if the resin thickness h is reduced,
The internal stress can be reduced, but on the other hand, in terms of moisture resistance, it is not possible to secure a sufficient amount of resin to block the semiconductor chip 1 from moisture from the outside world, resulting in easy deterioration.

In view of the above, the present invention relates to a resin structure that is improved to reduce the stress effect due to the resin thickness h, and utilizes the floating effect of the hollow filler to increase the amount of hollow filler in region 9. By including this, the longitudinal elastic modulus ER was lowered and the bending moment was reduced by 1.

Furthermore, in order to lower the longitudinal elastic modulus ER, the upper part 9a of the region 9 containing a large amount of hollow filler.

If the lower part is 9b, and the longitudinal elastic modulus of the upper part 9a is above ER and the longitudinal elastic modulus of the lower part 9b is above ER, then above ER,,,<
The relationship was made to be under ER. Hereinafter, using a hollow body filler such as a lath balloon and using two types of hollow body fillers having different average particle diameters, the hollow body filler in FIG. This is a heat sink insulated semiconductor device in which fillers are assembled.

By changing the average particle size of the hollow filler, the hollow filler with a small average particle size will fit into the gaps of the hollow filler with a large average particle size due to the floating effect of the hollow body itself, resulting in As a result, the hollow filler is concentrated in the upper part 9a of the region 9 containing a large amount of the hollow filler. That is, in the region 9 containing a large amount of hollow filler, there is a difference in the amount of hollow filler between the upper part 9a and the lower part 9b. , (The upper part 9a has a large amount of hollow body filler,
) Due to this difference in the amount of hollow body filler, the upper longitudinal elastic modulus ER of the resin upper part 9a can be made smaller than the lower longitudinal elastic modulus ER of the resin lower part 9b, and therefore, the longitudinal elastic modulus ER can be made even smaller. , the bending moment can be sufficiently reduced.

When using naturally produced shirasu balloons, for example, the particle size of the hollow filler is 50 to 300 μm, but particle size selection of the hollow filler is possible, and hollow filler particles with a particle size of 50 to 200 μm ( They are classified into products with an average particle size of 125 pm) and products with a particle size of 50 to 300 μm (average particle size: 175 μm) and are commercially available, so it is sufficient to use these two types.

In addition, recently, artificial hollow body fillers with an average particle size of 70 μm have been manufactured, and the above-mentioned natural hollow body fillers and artificial hollow body fillers may be used in combination, and N
In order to eliminate the influence of a-ions, etc., artificial hollow fillers having different average particle sizes may be mixed and used.

The amounts of the two types of hollow fillers are arbitrarily determined depending on the working efficiency, the volume occupied by the resin, the viscosity of the resin, and the like.

In all of the above examples, the semiconductor chip 1 and the insulating plate 3 were not destroyed by the bending moment.

The present invention can also be applied to a semiconductor device having a structure in which a semiconductor chip is mounted directly on a heat sink without using an insulating plate or via a support plate.

Further, the semiconductor chips may have any operating characteristics, and a plurality of semiconductor chips may be modularized together with other circuit elements.

〔Effect of the invention〕

As described above, according to the present invention, semiconductor chips can be
Semiconductor devices with good electrical characteristics without being destroyed,
It can be easily manufactured.

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the present invention, and Fig. 2 is a vertical cross-sectional view when a hollow filler and a resin mixed with a solid filler are used in an insulated triac. FIG. 7 is a longitudinal cross-sectional view of an insulated triac according to another embodiment. DESCRIPTION OF SYMBOLS 1... Semiconductor chip, 2... Heat sink, 3... Insulating plate, 4... Internal lead, 5... External lead, 6...
- Resin case, 7... Resin injection port, 8... Area containing a large amount of solid filler, 9... Area containing a large amount of hollow filler, 9a... Upper part of the area containing a large amount of hollow filler, 9b...Lower part of the region containing a large amount of hollow body filler.

Claims (1)

[Claims] 1. In a semiconductor device in which at least one semiconductor element is mounted on a heat sink and the periphery is sealed with an insulating resin, a solid filler and a semiconductor element are contained in the resin near the semiconductor element. A semiconductor device characterized in that a resin in a region away from the semiconductor device contains a large amount of hollow filler. 2. In the above claim 1, in the region away from the semiconductor element, the particle size of the hollow filler is larger on the side closer to the semiconductor element, and the particle size of the hollow filler is smaller on the side further away from the semiconductor element. A semiconductor device characterized by containing many small components. 3. The semiconductor device according to claim 1, wherein the semiconductor element is placed on a heat sink via an insulating plate.