JPS63252452A - Semiconductor device - Google Patents

Abstract

PURPOSE:To make the title device strong enough to withstand large power consumption sufficiently by fast sticking a heat sink onto the reverse surface of a bump bonded surface in a chip and remarkably lowering the thermal resistance of the semiconductor chip. CONSTITUTION:A solder bump is formed onto one surface of a semiconductor chip 1, and a heat sink 4 having various shapes made of an alloy such as the alloy of copper and tungsten is fixed extending over the whole surface of the reverse surface of one surface of the chip 1. The quantity of heat generated from the chip 1 is thermally conducted directly to a heat-sink fin 40, 41 or 42 for the heat sink 4, and dissipated into an atmosphere through the heat-sink fin, thus largely lowering the thermal resistance of the chip 1. Accordingly, a semiconductor device is strong enough to withstand large power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device including a Noritsu chip type semiconductor chip.

(Prior art) Flip-chip semiconductor chips have the advantage of greatly simplifying the manufacturing process of semiconductor devices because the wiring patterns formed on the semiconductor chip and the IC package can be connected without wire bonding. There is.

FIG. 3 is a cross-sectional view showing the structure of a semiconductor device equipped with a conventional flip-chip type semiconductor chip.

As shown in the figure, bumps 2 are formed on one side of the semiconductor deep 1, and are connected to a wiring layer 31 patterned on a wiring board 3 (face-down bonding). Since the main body of the semiconductor chip 1 is fixed to the wiring board 3 via the bumps 2, there is no need to die-bond the chip 1 onto the wiring board 3, unlike the case of wire bonding.

[Problem that the invention seeks to solve]

However, the above semiconductor device has the following problems. That is, since the semiconductor chip 1 is not die-bonded onto the wiring board 3, the amount of heat generated in the semiconductor chip 1 is not directly conducted to the wiring board 3 and radiated. As a result, most of the heat dissipation is limited to being conducted to the wiring board 3 through the bumps 2 or being convectively dissipated from the chip 1 body to the surrounding atmosphere, so the thermal resistance of the semiconductor chip 1 is large. Become. Therefore, in the conventional semiconductor device, a large practical limitation has occurred in that it is not possible to mount a semiconductor chip for high power use.

Generally speaking, in order to reduce material consumption and improve heat dissipation, it is generally desirable to make the thickness of the semiconductor wafer constituting the semiconductor chip 1 as thin as possible. However, according to the conventional technology, face-down bonding of a thin semiconductor chip also applies excessive mechanical stress to the chip, which impairs the reliability of the semiconductor device. Furthermore, in practice, it is technically difficult to accurately chuck a thin semiconductor chip, properly position it, and perform face-down bonding, and the workability is also lacking.

Due to the above-mentioned problems, flip-chip semiconductor chips, which have many advantages, are limited to small devices that handle low power, and cannot be used in a wide range of semiconductor devices, which is a major limitation. I had left it behind.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a semiconductor device that can be applied to a wide range of applications by improving the heat dissipation characteristics of a Noribu chip type semiconductor chip and by making the chip easier to handle.

(Means for Solving the Problems) In order to achieve the above object, a semiconductor device according to the present invention is characterized in that a heat sink is closely attached to the surface of the semiconductor chip opposite to the surface to which the bumps are bonded.

[Effect]

According to the present invention, since the semiconductor device is configured as described above, the amount of heat generated in the semiconductor chip is directly conducted to the heat sink and efficiently released into the surrounding atmosphere, reducing the thermal resistance of the semiconductor chip. It acts to reduce it significantly. Therefore, even in operations involving large power consumption, the temperature rise of the semiconductor chip is suppressed, the semiconductor device operates stably, and its reliability is increased.

〔Example〕

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in the explanations in the figures, the same elements are given the same reference numerals to avoid duplication of explanations.

FIG. 1 is a perspective view showing the configuration of a first embodiment having heat sinks 4 of different shapes. The figure (B) shows an example using heat sink fins 41 having a chevron-shaped fin structure,
FIG. 2C shows an example using heat sink fins 42 having a rectangular hollow structure. In any of the above embodiments, solder bumps are formed on one side of the semiconductor chip 1, and heat sinks 4 of various shapes made of, for example, an alloy of copper and tungsten are fixed to the entire surface of the opposite side.

The semiconductor chip 1 is made of, for example, a gallium-arsenide compound semiconductor, and the heat sink 4 is welded to the chip 1 via a gold-tin alloy layer. The coefficient of thermal expansion of the heat sink 4 is 6.9X1 by using copper-tungsten alloy as the material.
0'C-1, and is matched with the coefficient of thermal expansion of the semiconductor chip 1 made of a gallium arsenide compound semiconductor.

According to the above embodiment, the amount of heat generated by the semiconductor chip 1 is directly transmitted to the heat sink fins 40 and 41 of the heat sink 4.
．． Since the heat is conducted to 42 and dissipated into the atmosphere via this, the thermal resistance of the semiconductor chip 1 is significantly reduced. As a result, even if the semiconductor chip performs an operation that consumes a large amount of power, the generated heat is sufficiently radiated to the outside via the heat sink 4, so that, for example, the PN junction temperature does not rise. As a result, it works to improve the reliability of the semiconductor device.

Roughly speaking, according to the above embodiment, the heat sink 4 that is closely attached to the semiconductor chip 1 works to reinforce the mechanical hardness of the semiconductor chip 1, so that the thickness of the semiconductor chip can be reduced. When mounting the semiconductor chip 1 on the wiring board 3, the collet for handling only needs to check the heat sink 4, so that the semiconductor chip 1 can be mounted without applying unnecessary stress.

Furthermore, when mounting on the wiring board 3, the chuck mechanism can chuck the upper end of the heat sink 4 that is separated from the face-down bonding surface, so there is no need to be subject to spatial restrictions due to the structure of the chuck mechanism. do not have. As a result, it is possible to construct a semiconductor device in which semiconductor chips 1 are arranged at high density.

FIG. 2 is a sectional view showing the configuration of a second embodiment of the present invention. As shown in the figure, in this embodiment, the heat sink 4 that is closely attached to the semiconductor chip 1 has elastic fins 43 with a curved cross-sectional shape.
is configured to stand upright, and is in contact with the side surface 44 of a water cooling jacket that serves as the outer package or heat sink bus of the semiconductor device. According to this, the amount of heat generated by the semiconductor chip 10 is from the heat sink 4 to the fin 43.
Contact heat is conducted to the side surface 44 of the outer package or water-cooling jacket through the contact, and the thermal resistance of the semiconductor chip 1 can be significantly reduced.

Note that the present invention is not limited to the description of the above embodiments, and various modifications are possible.

For example, the semiconductor chip can be made of silicon, and the materials of the heat sink and heat sink fins are not limited to the above examples. Further, the curved fins shown in FIG. 2 are not limited to the upright shape of a plate-like body, but can also be formed in the upright shape of a linear body.

Furthermore, in the above embodiments, the heat sink is provided with heat sink fins, and the description is made assuming that heat conduction heat radiation or convection heat radiation due to air cooling is performed, but it is also possible to use a liquid-cooled heat sink. Furthermore, the bumps are not limited to those formed on the semiconductor chip in advance, but may be necessarily formed on the wiring board and then welded later.

〔Effect of the invention〕

As described in detail above, according to the present invention, since the heat sink is closely attached to the reflective surface of the bump bonding part of the chip, the thermal resistance of the semiconductor chip is significantly reduced, and the semiconductor chip can sufficiently withstand large power consumption. equipment can be provided. In general, according to the present invention, the heat sink reinforces the mechanical strength of the semiconductor chip, so the semiconductor chip can be formed thinly, and it also facilitates chucking, so the semiconductor chips can be arranged at high density.

[Brief explanation of the drawing]

Fig. 1 is a perspective view illustrating several different shapes of heat sinks showing the first embodiment of the present invention, Fig. 2 is a sectional view showing the configuration of the second embodiment, and Fig. 3 explains the conventional technology. FIG. DESCRIPTION OF SYMBOLS 1... Semiconductor chip, 2... Bump, 3... Wiring board, 4... Heat sink, 40.41, 42, 43
...Heat sink fin. Patent applicant Sumitomo Electric Industries Co., Ltd. Applicant agent Yoshiki Yoshiki
= Second embodiment Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A semiconductor device comprising a semiconductor chip having a bump bonding surface on one side, and a heat sink in close contact with the surface of the semiconductor chip opposite to the bump bonding surface. 2. The semiconductor device according to claim 1, wherein the semiconductor chip and the heat sink are welded together using an alloy.