JP2009188366A - Integral semiconductor heat dissipating substrate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor heat dissipating substrate in which a low thermal expansion coefficient and a high thermal conductivity function with favorable balance by integrally molding an insulating board, a Si-Al composite material and a fin with diffused junction, and an adhesion degree between Si and Al can be enhanced by coating a surface of Si powder with Al powder, and the generation of distortion is suppressed by a notch, and a heat dissipating effect (cooling effect) is improved by a passage hole of the fin etc. <P>SOLUTION: The semiconductor heat dissipating substrate is formed by integrally molding the insulating board of SiC, AlN etc., a composite material composed of the Si-Al composite material and the fin of an Al board with diffused junction. The Si of the Si-Al composite material is more than 50 vol% and less than 80 vol%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor heat dissipation substrate having a low thermal expansion coefficient and a high thermal conductivity.

As a conventional technique, an Al-Si alloy containing 13 wt% or more and 80 wt% or less of Si is rapidly cooled by a die casting method at a rate of 300 to 800 K / sec, and then molded, so that the crystal grain size of the Si phase is 50 μm. Hereinafter, there is a heat dissipating material having a thermal expansion coefficient of 16 × 10 ⁻⁶ K ⁻¹ or less, a thermal conductivity of 80 W / m · K or more, and high thermal conductivity and low thermal expansion. (See Patent Document 1)

In addition, as another conventional technique, in order to ensure wettability with the brazing material or metal as desired, a step of surface-treating the bonding surface of the insulating substrate in advance in order to secure wettability with the brazing material or metal in advance. Placing the surface-treated ceramic particles on an insulating substrate, placing the brazing material on the ceramic particles, heating and melting the brazing material, and infiltrating the gap between the ceramic particles; A laminate comprising a bonded body of a metal matrix composite and an insulating substrate provided with a heat sink function, which can be manufactured by a method including a step of manufacturing the reacted metal matrix composite and bonding the metal matrix composite and the insulating substrate. Some have been achieved by heat dissipation members. (See Patent Document 2)
JP 2001-288526 A JP 2001-217362 A

  The former is formed by quenching by die casting, is not formed by diffusion bonding (sintering) according to the present invention, and is not a form in which an insulating substrate, fins, or the like are provided.

  In the latter case, a brazing material is disposed. As is well known, the brazing material has a poor thermal conductivity and has a practical problem.

  The present invention solves the problems of such a conventional configuration. By integrally forming an insulating plate, a Si-Al composite material, and a fin by diffusion bonding, a low thermal expansion coefficient is obtained. And high thermal conductivity function in a well-balanced manner, and by coating the surface of the Si powder with Al powder, the adhesion between Si and Al can be improved, and the occurrence of distortion is suppressed by the notch, and the fin holes An object of the present invention is to provide a semiconductor heat radiating substrate having a further improved heat radiating effect (cooling effect).

In order to achieve the above object, the present invention provides a semiconductor heat dissipation formed by integrally forming an insulating substrate made of SiC, AlN or the like, a composite material made of a Si-Al composite material, and a fin made of an Al plate by diffusion bonding. The Si-Al composite material has a Si content of 50 vol% or more and 80 vol% or less.
The thermal expansion coefficient of the Si—Al composite material is set to 7 × 10 ⁻⁶ K ⁻¹ or more.
The thermal conductivity of the Si—Al composite material is 80 W / m · K or more.
The surface of the Si powder of the Si-Al composite material is coated with Al powder.
A notch is formed in the lower part of the insulating substrate and the upper part of the fin.
The fin is provided with a burring through hole.
An uneven portion is provided on the surface of the fin.
A bar is provided between the fins.
It is integrally formed by diffusion bonding at 450 ° C. or higher and 530 ° C. or lower.

1) A low thermal expansion coefficient and a high thermal conductivity are functioned in a well-balanced manner by integrally molding an insulating substrate, a Si—Al composite material, and a fin by diffusion bonding.
2) The thermal expansion coefficient of the Si—Al composite material is set to 7 × 10 ⁻⁶ K ⁻¹ or more and the thermal conductivity is set to 80 W / m · K or more, thereby having a particularly well-balanced function.
3) By coating the surface of Si powder with Al powder, adhesion with Al can be improved during sintering.
4) By providing a notch in the lower part of the insulating substrate and the upper part of the fin, it is possible to improve adhesion and suppress the occurrence of distortion during diffusion bonding (sintering).
5) By providing burring through-holes in the fins, the flow of water and air can be turbulent, and the heat dissipation effect is improved.
6) By providing an uneven part and a rod on the fin, the turbulent flow can be made more and the heat dissipation effect can be further improved.
7) It can be sintered at a low temperature of 450 ° C. or higher and 530 ° C. or lower, and a Si—Al composite material can be formed.

Reference numeral 1 denotes a semiconductor heat dissipation substrate.
Reference numeral 2 denotes an insulating substrate made of SiC, AlN, or the like (four locations in this embodiment), and has substantially V-shaped groove-shaped notches 2a on both sides of the lower portion.
3 is a fin made of Al, and has a plurality of (7 locations in this embodiment) burring-processed through-holes 3a.
The number, position, size, etc. of the through holes 3a may be determined as necessary.
Reference numeral 4 denotes a Si—Al composite material, which is formed by forming a sintered body by diffusion bonding processing. The insulating substrate 2 is disposed at the upper portion, and the fins 3 are disposed at the lower portion.
As a processing method, in a vacuum chamber (not shown), heating is performed with a pressure body K (100 MPa or more) made of carbide or the like and an electrode (flowing current) made of graphite K1 (temperature 450 ° C.). Sintering is performed at 530 ° C. or lower).
At this time, in order to set Si to 50 vol% or more and 80 vol% or less, to set thermal expansion coefficient to 7 × 10 ⁻⁶ K ⁻¹ or more as thermal characteristics, and to set thermal conductivity to 80 W / m · K or more, vol of Si and Al %.
In addition, in order to further improve the adhesion (bonding) between Si and Al, the surface of the Si powder is coated with Al powder, so that there is no mutual contact between Si and the adhesion (adhesion degree) is improved.

The data of the semiconductor heat dissipation substrate 1 will be described below.
Table 1 shows the thermal characteristics of the semiconductor heat dissipation substrate of the present invention.
It can be seen that when Si is 60 vol%, the thermal conductivity is 100 W / m · K or more and the thermal expansion coefficient is 8 × 10 ⁻⁶ K ⁻¹ or more.

In addition, in the case where the surface of the Si powder is coated with Al powder, as shown in Table 2, there are few non-adhered portions HB (black dot portions) due to an air layer or the like, and the adhesiveness is high, so that the thermal conductivity is high.

Next, another embodiment will be described below.
The fins 23 are provided with uneven portions 23b on the surface, and can be generated by mixing large turbulent flow or small turbulent flow with inflowing air or water, thereby improving the heat dissipation effect.

  The fin 33 is formed by penetrating an Al rod 33c, and in particular, can generate turbulent flow around the rod 33c and enhance the heat dissipation effect.

In the above embodiment, the good thermal conductivity of Al and the good thermal expansion coefficient of Si are combined in a balanced manner. The shape and number of notches, the position and number of through holes, the position and number of rods, etc. Can be determined as needed.
Moreover, although the motor circuit board of a hybrid vehicle etc. are considered on an insulating board, it does not specifically limit.
Furthermore, although air and water are allowed to flow into the fins, they may be determined according to the intended use.
Furthermore, all Al uses pure Al.

1 is a partially longitudinal front view of a semiconductor heat dissipation substrate showing a first embodiment of the present invention. The top view of the board | substrate for semiconductor thermal radiation which shows 1st Example of this invention. 1 is a partially longitudinal side view of a semiconductor heat dissipation substrate showing a first embodiment of the present invention. 1 is a Si coating diagram of a semiconductor heat dissipation substrate showing a first embodiment of the present invention; FIG. The processing state figure of the board | substrate for semiconductor thermal radiation which shows 1st Example of this invention. The side view of the fin of the board | substrate for semiconductor heat radiation which shows 2nd Example of this invention. The side view of the fin of the board | substrate for semiconductor heat radiation which shows 3rd Example of this invention.

Explanation of symbols

1 --- Semiconductor heat dissipation substrate 2 --- Insulating substrate 2a --- Notch 3 --- Fin 3a --- Through hole 33c--Bar 4 --- Si-Al composite material HB-- --Non-contact part

Claims (10)

  A semiconductor heat dissipation substrate made of a Si-Al composite material obtained by sintering Si powder and Al powder, wherein Si is 50 vol% or more and 80 vol% or less.   A semiconductor heat dissipation substrate in which an insulating substrate made of SiC, AlN, or the like and an Al plate fin are integrated by diffusion bonding simultaneously with sintering of the semiconductor heat dissipation substrate according to claim 1. 2. The semiconductor heat dissipation substrate according to claim 1, wherein the Si-Al composite material has a thermal expansion coefficient of 7 × 10 ⁻⁶ K ⁻¹ or more.   4. The semiconductor heat dissipation substrate according to claim 1, wherein the thermal conductivity of the Si-Al composite material is 80 W / m · K or more.   5. The semiconductor heat dissipation substrate according to claim 1, wherein the Si surface of the Si-Al composite material is coated with Al powder.   6. The semiconductor heat dissipation substrate according to claim 1, wherein a notch is formed in a lower portion of the insulating substrate and an upper portion of the fin.   7. The semiconductor heat dissipation substrate according to claim 1, wherein a burring-processed through-hole is provided in the fin.   8. The semiconductor heat dissipation substrate according to claim 1, wherein an uneven portion is provided on a surface of the fin.   9. The semiconductor heat dissipation substrate according to claim 1, wherein a rod is provided between the fins so as to penetrate therethrough.   It is integrally formed with a horizontal electric sintering machine at a diffusion bonding temperature of 450 ° C or higher and 530 ° C or lower and a pressure of 100 MPa or higher. 9. The semiconductor heat dissipation board according to 9.

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