JPS58103156A - Substrate for semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the substrate for mounting of the semiconductor element having superior heat radiation by a method wherein a film consisting of an organic matter having the electrically insulating property and moreover having comparatively favorable thermal conductivity is coated as a thin layer on the surface of a tape of metal, alloy or composite thereof having favorable thermal conductivity. CONSTITUTION:The metal substrate 1 for mounting of the Si semiconductor element 6 and coated with the SiC thin film 4 is manufactured according to the plasma CVD method, and copper of 1.0mm. thickness and containing Zr is used for the metal substrate 1. The plasma CVD method is performed using a capacitive coupling type glow discharge device and mixed gas of 1X10<-2> Torr of SiH4 and CH4, and by heating the substrate at 500 deg.C. Accordingly the substrate 3 for mounting of the semiconductor coated with the SiC thin film 4 of 3mum thickness having favorable adhesion, having the dielectric strength characteristic of 3MV/ cm or more, having the coefficient of thermal expansion approximated to the Si element to be mounted and having superior heat radiation is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a substrate material for mounting an element on an integrated circuit device, which is particularly capable of dissipating heat generated in a semiconductor element with high efficiency, and having an electrically insulating property. It provides substrate materials.

BACKGROUND OF THE INVENTION For integrated circuits that require high reliability, pancage methods such as low-melting glass, ceramic packages, and multilayer ceramic packages have traditionally been used.

In this case, the semiconductor element is generally mounted on a ceramic substrate via a metal rising layer or a plating layer for adhesion. This substrate itself can only be used as a part of the package material that performs a hermetic sealing function, and is required to have properties such as electrical insulation and a small mismatch in thermal expansion coefficient with the semiconductor element. For this reason, conventionally Aj
1208. Be0.2Mg0. Sintered ceramic materials such as SiO, etc. are widely used.

However, in recent years, integrated circuit elements have become denser and larger, and the higher density has led to an increase in the amount of heat generated from the semiconductor elements, and the requirements for heat dissipation properties of substrate materials are becoming greater. For this reason, the resin mold type I'
The material for the lead frame used in C is changing from Ni alloy to Cu alloy. There is also a strong demand for heat dissipation for integrated circuits in low-melting-point glass-ceramic packages and multilayer ceramic packages, but Aj1208
Y2Mg0Sin has inherently poor thermal conductivity,
It is difficult to answer this request. BeO, a material with slightly good thermal conductivity
However, this method has the drawbacks of being expensive and toxic. Also, the most commonly used A608 is its molding,
Malfunctions of integrated circuits caused by the irradiation effect on semiconductor elements by alpha rays generated from U mixed during sintering are becoming a major problem as demands for higher performance and reliability become stronger.

The present invention aims to eliminate such drawbacks and provide a substrate material for mounting semiconductor elements that has better heat dissipation properties than conventional ceramic substrates.

That is, the substrate material for mounting a semiconductor element of the present invention uses a metal, alloy, sintered body, or a composite tape of these as a base metal, has electrical insulation properties on the surface, and has a relatively low heat conductivity. It is coated with a thin layer of inorganic material that has good thermal conductivity. The base metal mentioned here is Ni.

In recent years, various types of thin plate tapes such as highly electrically conductive Cu alloys have been developed for IC lead frames, as well as copper clad tapes that allow the required thermal conductivity and mechanical properties to be set arbitrarily. It is particularly effective to use composite plates such as stainless steel clad copper. In addition to diamond, materials coated on this surface include BN, AJO, etc.
Ceramic materials such as AjN, SiC, Si, N4°8-Y, 08#2Mgoe SiO, etc. are effective, and these materials and their combinations should be selected appropriately according to the required characteristics of the circuit board, and the film thickness can also be controlled arbitrarily.

By using such a composite substrate called heptadramic-coated metal, the composition ratio of material combinations can be selected according to the differences in semiconductor elements and the required characteristics and price of semiconductor devices. In addition, it can accommodate semiconductor devices that are becoming larger. In addition to Si integrated circuits, it is also possible to provide a substrate material for mounting semiconductor elements in integrated circuit devices that can be used as a packaging material for GaAs integrated circuits, which are expected to be put into practical use in the future.

The methods of coating ceramics mentioned above include physical vapor deposition (PVD) and chemical vapor deposition (CVD).
It is preferable to use a vapor phase plating method such as

In the present invention, the thermal conductivity of the base metal is 0, BOC
al/cm, sec" limited to 0 or more (i') Ha,
Conventionally used Aj, 0812Mg0. S io
This cannot be obtained with a substrate material using baked clay lamic such as G. In order to obtain high conductivity, more and more ICs will be used in the future.
This is to cope with the increasing demand for heat dissipation in However, in the present invention, thermal expansion characteristics, which had traditionally been one of the required characteristics of a substrate for mounting semiconductor elements, were not particularly taken into account when selecting the base metal.In recent years, die bonding technology and sealing technology This is because low-temperature processing technology in the IC mounting process has significantly advanced due to the development of technology, and this has not become a major problem except when large semiconductor elements are used. However, if thermal expansion characteristics are required, MO, W
.

The required characteristics can be satisfied by using a composite plate such as copper-clad or Kovar-clad copper as the base metal.

Moreover, the reason why the thickness of the surface coating was limited to 0.1 to 10 μm is that the required electrical insulation cannot be obtained with less than this.
This is because if the amount exceeds this value, the cost for coating becomes extremely high, making it impractical from an economical point of view.

FIG. 1 is a cross-sectional view of a semiconductor device on which a semiconductor element is mounted using the substrate of the present invention, in which 1 is a metal plate or composite metal plate with good thermal conductivity of the element, and 2 is a coating on the surface. A substrate 3 is formed using the insulating coating layer. 4 is a metal rising layer, 5 is an Au plating layer, and a semiconductor element 6 is mounted thereon.

This will be explained in detail below using examples.

Example 1 A metal substrate coated with a SiC thin film for mounting a Si semiconductor element was fabricated by plasma CVD.

Zr-containing copper having a thickness of 1.0 cm was used for the metal substrate.

Plasma CVD uses a capacitively coupled glow discharge device.
The substrate was heated to 500°C using a mixed gas of SiH and CH at xlO" Torr. 8 MV/ffi
It was possible to obtain a substrate for mounting a semiconductor, which was coated with a SiC thin film of 8 μm having the above dielectric strength characteristics with good adhesion and had excellent heat dissipation and a coefficient of thermal expansion similar to that of the Si element on which it is mounted.

Example 2 A metal substrate coated with an Al2O8 thin film on which a Si semiconductor element was mounted was fabricated by an ion blasting method.

An oxygen-free pure copper plate having a thickness of 0.511 m was used as the base metal, and ion blating was carried out by the following method.

A, l, 03 sintered body was used as the raw material and evaporated by electron beam heating. A portion of the evaporated material was ionized by applying an oxygen pressure of 4×10”rorrms frequency (13,56 MHz) of 100 to 20 ow, and the substrate was heated to 200° C. to coat AlzOa to a thickness of 2.0 μm.8
It was possible to obtain a substrate for mounting a semiconductor element, which has a transparent insulating thin film having dielectric strength characteristics of MV/VI or higher, has good adhesion, and has excellent heat dissipation properties.

As explained above, on a highly thermally conductive base metal,
By corrugating diamond or ceramic into a thin layer, a substrate for mounting a semiconductor element with excellent heat dissipation properties was obtained. This has made it possible to fully cope with the increasing size and density of integrated circuits.

[Brief explanation of the drawing]

FIG. 1 is a horizontal sectional view of a semiconductor device using a substrate according to the present invention. 2: insulating coating layer, 3: substrate, 4: metal rising layer, 5: Au plating layer, 6: semiconductor element. Piece 1

Claims (4)

[Claims] (1) Thermal conductivity is 0.2 Ca I/cm, se
The surface and side surfaces of a metal plate or a composite metal plate with an e'G or higher are coated with a thin layer of electrically insulating inorganic material with a thickness of 0.1-10 μm by PVD or CVD. A semiconductor device substrate for mounting semiconductor elements. (2) The substrate for a semiconductor device according to claim (1), wherein the semiconductor element is Si or GaAs. (3) The metal plate or composite metal plate has N r + Cu,
Aj + Various high thermal conductivity type Cu alloys, copper flooded stainless steel clad copper, or M. The substrate for a semiconductor device according to claim (1), wherein the substrate is a sintered body mainly composed of W. (4) The coating layer is BN, Aj208. AjIN, SiC
,8i8N, . YsOs, 2Mg0. S+02. The substrate for a semiconductor device according to claim (1), characterized in that the substrate is made of diamond.