JPS58204559A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device which has resistance to thermal stress similar to that of a conventional one and good thermal conductivity by forming an annular electrode plate, soldering the plate to the projected periphery of a metal stud base which is projected at the center and raising the upper surface of the plate from the upper surface of a base. CONSTITUTION:The projected part of a metal stud base 10 is inserted into a hole of an electrode plate 11 and soldered to the plate. The upper surface of the projected part of a base is lower than the upper surface of the plate 11. Thus, a solder between the plate 11 and a semiconductor pellet 3 is thin, and a solder between the projected part of the base and the pellet 3 becomes thick. According to this structure, since the thermal stress produced by the base is alleviated by the plate and the base is bonded through a solder directly to a pellet, good heat sink can be obtained. Accordingly, a semiconductor device has a strength against thermal stress similar to that of a conventional one, and good thermal conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to semiconductor devices, and more particularly to metal stud-based structures.

Generally, the metal stud paste used in semiconductor devices is made of a material with excellent thermal conductivity, but it has a large coefficient of linear expansion, and if semiconductor pellets are bonded directly, large distortions will occur due to the difference in the coefficient of linear expansion between the metal stud paste and the semiconductor pellet. generated and the semiconductor pellet is destroyed. Therefore, IigI
A metal having an expansion coefficient comparable to that of the semiconductor pellet and a longitudinal elastic modulus larger than that of the metal stud paste is inserted between the stud paste and the semiconductor pellet, and is used as a stress relaxation material. This is generally called an electrode plate,
This electrode plate is made thick in order to sufficiently preserve the semiconductor pellet. However, in general, this type of heat conduction is poor and has the drawback of deteriorating the characteristics such as thermal resistance of semiconductor devices.

The purpose of this invention is #! It is an object of the present invention to provide a semiconductor device which suppresses the influence of thermal stress of a metal stud hese having a large coefficient of expansion on a semiconductor pellet and has good thermal characteristics.

The mold of the present invention is made by forming an annular electrode plate and adhering it around the convex part of a metal stud base with a convex center part through a brazing material, so that the upper surface of the electrode plate is from the upper side of the metal stud base. The goal is to make it more expensive. Thermal stress caused by the metal stand space is alleviated by the electrode plate, and since the metal stud base with good thermal conductivity is bonded to the th contact semiconductor pellet via the brazing material, good thermal characteristics can be maintained.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

The semiconductor device numbered 9 and 1 is shown in 1'lA. The electrode plate 2 is adhered to the metal stud base l through a brazing material, and the half-metal pellets 3 are further layered through the brazing material.

Semi-4K Pellet 3Vi Gracivation, - or R
The electrode plate 2 is of the i''V type.The electrode plate 2 has a sufficient thickness to relieve the thermal stress of the metal stud base 1 and protect the metal stud base 1.However, in general, The electrode plate 2 used has poor thermal conductivity, which contributes to deterioration of the thermal characteristics of the element.
Since there is a large difference in tensile modulus between the two, the selection of the brazing filler metal used for the contact layer between the two is also important.

FIG. 2 shows the combination number of the ring at electrode plate 1 and the metal stud base 10 according to the present invention. Telephone・□”Please□.

The protrusion of the metal stud base 10 is inserted into the hole of the electrode plate 11 and brazed, and the upper surface of the base protrusion is lower than the top surface of the electrode plate 11. As a result, the solder thickness between the T& plate 11 and the semiconductor pellet 3 is thin, and the solder thickness between the upper surface of the base convex portion and the semiconductor pellet 3 is thick. Since the coefficient of linear expansion of the 11L board 11 and the semiconductor pellet 3 is t'X Fi, the brazing filler metal needs to be used only for the purpose of adhesion, and the solder thickness is thin and does not give any negative effect to the 4 semiconductor pellet 3. do not have. but,
Semiconductor pellet 3 and metal stud paste 10? The fM expansion coefficient is large, and the solder metal serves not only as a contact layer but also as a stress relaxation material, so the solder thickness must be thick. 0gE satisfies the MiJs solder thickness condition in the present invention. . Furthermore, if a grating pellet 1 is used for the semiconductor pellet 3 in FJ, the grating 7 section becomes the upper part of the electrode &11, and the structure is such that no stress is applied to the grating section.

In addition, in this structure, the metal stud base 10 convex portion ″1・
Power・J7 for gold 1)”-’C-,X”0′! ″1&&1
The thickness of the electrode plate 11 is held in place by the hole in the electrode plate 11, and the thickness of the electrode plate 11 is approximately 1/2 that of the steel electrode plate 2. . Furthermore, in this structure, which suppresses thermal stress by the electrode plate 11, the brazing material used for adhering the metal stud base 10 and the electrode plate 11 is 1/2 stronger than the brazing material used in the conventional structure of the first section. One length can be used even with a short-cut.

FIG. 3 shows the degree of stress relaxation of the convex portion of the metal stand base 10 by the electrode plate 11. The vertical axis represents the strain gto on the metal stud base convexity caused by heat, and the horizontal axis represents the external diameter of the L pole plate φl! The ratio φtt/φxe of the metal stud paste convex diameter φ+o (=electrode plate inner diameter) is shown.

If the ratio of the elasticity retention ridge Elf of the electrode plate and the longitudinal elastic modulus E1o of the metal stud base is constant fc, then the internal capacity of the electrode ring φ
If 10 becomes sharp, metal stud base distortion '10 is +
The strain approaches the strain of the 1iW4 studded paste material itself, and conversely, if the inner diameter φ1° becomes smaller, the strain approaches the strain of the electrode material itself. φ
(2) Since the strain tends to be constant when /φ10≧2, it is sufficient that the inner diameter of the electrode plate is about 1/2 of the outer diameter. !
, the ratio of their longitudinal elastic modulus E1°/E11, or
When the difference in the expansion coefficient (α10-α1-) is used as a parameter, when the value is small, the metal stud base convex strain ε10 increases, and conversely, when it is large, the metal stud base convex strain IIO decreases. Work in the direction of becoming. Therefore, in order to keep the metal stud base convex strain 110 small, it is sufficient to use a material with a lower modulus of longitudinal elasticity and a smaller linear expansion coefficient than the metal stud paste as the electrode material, which has not been used in the past. Any material is fine.

FIG. 4 shows how the heat 12 generated in the semiconductor pellet 3 is transferred. The heat generated by the semiconductor pellet 3 is transmitted to the electrode plate 11 and the convex portion of the metal stud base 10 via the brazing material. For example, the anastomosis and heat generating part of a glacivation pellet is inside the moat, and since the convex part of the gold stud base 10 with good heat conduction is in contact with it, most of the heat flow 12 is transmitted to the convex part of the gold stud base 10. Thermal characteristics (thermal resistance) are omitted.

According to Yumei Moto, it is possible to obtain a semiconductor device that has the same strength against thermal stress as conventional products and has good thermal conductivity.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a semiconductor device with a conventional structure, and FIG. 2 is a cross-sectional view showing a semiconductor device according to the present invention. and the ratio of the metal area base convex diameter φ10 φ1
．． FIG. 4 is a diagram showing the strain j1· of the convex portion of the gold maple base having tj at /φ1°, and FIG. 4 is a diagram showing how heat flows in the semiconductor device shown in FIG. l, 10... Gold-stud base, 2.11... Electrode plate, 3... Semiconductor pellet, 12... Heat flow. Fu 1 figure 211

Claims (1)

[Claims] 1. A metal stud base with a protrusion on the side to which the semiconductor pellet is brazed, an annular electrode plate brazed around the protrusion, and a half-metal stud base brazed on the protrusion and the electrode plate.
The brazing material between the electrode plate and the semiconductor pellet is wider than the brazing material between the protrusion and the semiconductor pellet, and is 11L.
A semiconductor device characterized in that the electrode plate is made of a material having a longitudinal elastic modulus thicker than that of the metal stud base and a tensile modulus approximately equal to that of the semiconductor pellet.