JP2663581B2 - Semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a high withstand voltage diode in which a plurality of semiconductor dies are stacked.

[Conventional technology]

Conventionally, a die of this type of semiconductor device has a mesa structure as shown in FIG. 5, and a glass 53 is embedded in a mesa groove 56. Then, as shown in FIG. 4, a plurality of such dies 42 are stacked between heat sinks 41, and the periphery thereof is sealed with glass 43 to produce a high breakdown voltage diode.

[Problems to be solved by the invention]

The above-mentioned conventional high breakdown voltage diode has a disadvantage that the shape of the die and the manufacturing process for stabilizing the surface by the glass 53 are special, and the manufacturing line cannot be shared with other diodes and the like.

[Means for solving the problem]

The high breakdown voltage diode according to the present invention includes a plurality of semiconductor dies each having a silicon protrusion on the surface.

Although the conventional semiconductor device described above forms a mesa groove on the side of the die and fills the groove with glass to ensure insulation between the die and the die, the present invention uses a planar type die to form a silicon protrusion on the surface. To ensure the insulation between the dies.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of one embodiment of the present invention. Reference numeral 12 denotes a semiconductor die which is stacked in plural. Reference numeral 11 denotes a heat sink which sandwiches the stacked semiconductor dies 12 from both sides. Reference numeral 13 denotes a sealing glass, which is mainly welded to the semiconductor die 12 to perform hermetic sealing.

FIG. 2 is a cross-sectional view of the semiconductor die 12 of FIG. 21 forms a P-type diffusion layer 22 on a semiconductor substrate (N-type),
The epitaxial layer 24 of the same conductivity type is
mm. Electrodes 25 and 26 are formed on the front and back of the die, respectively. As the material of the electrodes 25 and 26, gold or silver which easily forms a eutectic with silicon of the die substrate is used.

FIG. 3 is a sectional view of a die according to another embodiment of the present invention.
In this embodiment, there is no difference in forming a silicon protrusion, but since the high-concentration diffusion layer 31 having the same shape as the substrate is formed around the die surface, the spread of the depletion layer on the surface is stopped here. Thus, a more stable one is obtained.

〔The invention's effect〕

The present invention forms a convex part of the epitaxial growth layer on the die surface, creates a gap in a part where the die does not connect to the die by laminating it, and fills the gap with sealing glass to improve the insulation between the die and the die. I do. The stability of the characteristics is also improved by welding the sealing glass to the die surface. By adopting such a structure, what conventionally required a special process such as mesa etching or glass surface stabilization can be manufactured by using selective diffusion and epitaxial growth which are common in semiconductor manufacturing processes.

[Brief description of the drawings]

1 is a sectional view of one embodiment of the present invention, FIG. 2 is a sectional view of a die in FIG. 1, FIG. 3 is a sectional view of a semiconductor die in another embodiment of the present invention, and FIG. FIG. 5 is a sectional view of the semiconductor device, and FIG. 5 is a sectional view of the die in FIG.

Claims (1)

(57) [Claims] 1. A semiconductor device manufactured by stacking a plurality of semiconductor dies, wherein a silicon projection is formed on the surface of the die.