JPH021150A - Method for manufacturing semiconductor device substrate with excellent heat dissipation properties - Google Patents

Abstract

PURPOSE:To enhance a close contact property of a silicon dioxide (SiO2) layer by forming the silicon dioxide layer with a specific thickness on the surface of an aluminum nitride sintered substrate. CONSTITUTION:The surface of an AlN sintered substrate is oxidized in an atmosphere at an oxygen partial pressure of 10<-2> to 1atm. and at a steam partial pressure of 10<-3>atm. or lower and under a condition that it is heated and kept at a temperature of 1100 to 1500 deg.C; a surface oxide layer composed mainly of aluminum oxide is formed. An SiO2 layer 1b with an average film thickness of 0.05 to 5mum is formed on the surface of the AlN sintered substrate 1a having this surface oxide layer. Thereby, an extremely high close contact property with reference to the SiO2 layer is secured by the surface oxide layer formed on the surface of the substrate; a very excellent heat-dissipating property can be secured by the AlN sintered substrate; accordingly, it is possible to comply with an improvement in an integration density of a semiconductor device sufficiently satisfactorily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention utilizes aluminum nitride (hereinafter referred to as aluminum nitride), which has good thermal conductivity and therefore provides excellent heat dissipation.

The present invention relates to a substrate for a semiconductor device in which a silicon oxide layer (hereinafter referred to as 8iQ2) has extremely good adhesion to the surface of a sintered base (hereinafter referred to as AffiN).

[Conventional technology]

Conventionally, as a substrate for a semiconductor device with excellent heat dissipation properties, 2 has been used, for example, as described in Japanese Patent Application Laid-Open No. 62-28847,
It has been proposed that a 5iQ2 layer is formed on the surface of an AgN sintered substrate by a sputtering method, a sol-gel method, or a photochemical vapor deposition method.

It is also known that a printed circuit can be formed on the surface of this 5iQ2 layer using, for example, a conductor paste or a resistor paste, and the printed circuit can be put to practical use by baking it.

[Problem to be solved by the invention]

However, in recent years, as electronic devices have become more sophisticated, lighter, thinner, and smaller, the degree of integration of hybrid modules has also increased, and as a result, it has become impossible to avoid an increase in the amount of heat generated per unit. , the above-mentioned conventional substrate is A1. which has excellent thermal conductivity. Although excellent heat dissipation is ensured by the N sintered base, the adhesion between the AtN sintered base and the 8102 layer is insufficient, and the increased heat generation tends to cause peeling between them, reducing reliability. Problems are starting to arise.

[Failure to solve the problem]

Therefore, the inventors of the present invention, etc., from the above-mentioned viewpoint.

As a result of research to improve the adhesion of the 5i02 layer to the AtN sintered substrate, it was found that the surface of the AtN sintered substrate had an oxygen partial pressure of 10 to 1 atm and a water vapor partial pressure of 1O-3.
When an oxidation treatment is performed under conditions of heating and holding at a temperature of 1100 to 1500°C in an atmosphere below atmospheric pressure to form a surface oxide layer mainly composed of aluminum oxide, the surface oxide layer formed on the surface of the substrate becomes , 810□ layer because of its extremely strong bond.

They found that during this period, peeling caused by heat generation no longer occurs.

This invention was made based on the above findings.

Average layer thickness: At with a surface oxidation layer of 0.2-20 μm
8 with an average layer thickness of 0.05 to 5 μm on the surface of the N sintered substrate.
The present invention is characterized by a semiconductor device substrate having an i02 layer and having excellent heat dissipation properties.

In addition, in the substrate of this invention, the average layer thickness of one surface oxidation layer is set to 0.2 to 20 μm because the thickness is 0.2 μm.
If the thickness is less than 20 μm, the adhesion of the 8i02 layer to the substrate surface will not be fully satisfactory and the problem of peeling will not be completely solved. This is because the average layer thickness of the 8102 layer formed on the surface oxidation layer is 0.05 to 5.
μm is defined as 1 if the thickness is less than 0.05 μm.
For example, if the adhesiveness of the paste used for circuit printing with the fired layer is insufficient, on the other hand, if the thickness exceeds 5 μm,
This is also because the excellent heat dissipation properties of the base body no longer function adequately.

Further, the substrate of the present invention can be used as a single-layer substrate, and after forming a printed circuit thereon, a glass powder such as borosilicate glass is mixed with an organic binder to form a strip. With this printed and attached to the surface of the board, two or more boards are stacked, and this stack of boards is
Heating and firing at a temperature equal to or higher than the softening point of the glass powder,
It may also be used as a multilayer substrate formed by mutually bonding.

〔Example〕

Next, the substrate of the present invention will be specifically explained using examples.

First, Af having an average particle size of 3 μm was used as a raw material powder.
Using fiN powder, temperature: 180 in nitrogen atmosphere at normal pressure
Sintered at 0°C for 120 minutes.

An AtN sintered substrate having dimensions of diameter: romxx and thickness: 3 is formed, and then on the surface of this substrate.

In an atmosphere with oxygen partial pressure: 10 atm, water vapor partial pressure, 10 atm, temperature: 1300°C and maintained for a predetermined period of time.

A surface oxidation layer having an average layer thickness shown in Table 1 was formed by performing oxidation treatment under the following conditions.

On this.

(a) Target material: High purity quartz glass with a purity of 99.9%.

Target dimensions: Diameter 3mm x height Low.

Electric crab 10OW.

Base rotation speed: l Or, p, m,.

Sputtering time 2 predetermined times, High frequency sputtering method under the conditions of.

(b) Ethyl silicate: 34'7.9, ethyl alcohol: 500 J, and 0.3% HC1 aqueous solution: 1
A mixture of 90.2I and 500 r, p, m
・Sprinkle it on the surface of the rotating base for 10 seconds and bring it to a temperature of 28
A sol-gel method consisting of holding at 00°C for 10 minutes and firing as one cycle, and repeating this cycle until a predetermined thickness. (C) Reaction gas: volume ratio, 8i2H4/02
-0.015゜Reaction vessel internal pressure 0.2 torr
.

Substrate temperature = 150°C.

Light: Mercury lamp generated light, Reaction time 2 predetermined times.

Photochemical vapor deposition method (photoCVD method) under the following conditions.

Substrates 1 to 8 of the present invention were manufactured by forming two 5-inch layers having the average layer thickness shown in Table 1 using any of the methods (a) to (C) above.

For the purpose of comparison, the conventional substrate 1-- was prepared under the same conditions except that the surface oxidation layer was not formed by oxidation treatment on the substrate.
3 were produced respectively.

Next, let's talk about the various boards obtained as a result.

In addition to measuring thermal conductivity using the laser flash method,
A peeling test was conducted to evaluate the adhesion between the substrate and the 8102 layer.

In the peeling test, as shown in a schematic perspective view in FIG.
A conductor of Ag-20 wt % Pd alloy powder was screen-printed on an area of Then, a first-stroke fired layer 2 is formed, and then 5 nm of oxygen-free copper wire 4 with a diameter of 20.9 mm is formed on this layer.
-Pb eutectic alloy solder 3 is brazed at a temperature of 215°C to the state shown in Figure 1, and in this state, the oxygen-free copper wire 4 is pulled in the T direction to determine the peeling strength (peel strength) was measured. The results of these measurements are shown in Table 1.

〔Effect of the invention〕

From the results shown in Table 1, substrates 1 to 8 of the present invention exhibit significantly high thermal conductivity similar to conventional substrates 1 to 3, and exhibit much higher peeling strength than conventional substrates while maintaining excellent heat dissipation. It is clear that the adhesion of the 5i02 layer to the substrate is extremely high.

As mentioned above, in the substrate of the present invention, the surface oxidation layer formed on the surface of the substrate ensures extremely high adhesion with the 8102 layer, and the AtN sintered substrate ensures even better heat dissipation. Therefore, it has industrially useful characteristics such as being able to respond satisfactorily to improvements in the degree of integration of semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a peeling test method. 1...Substrate, 1a...Base. 1b...5i02 layer, 2... Paste firing layer. 3...Solder, 4...Oxygen-free copper wire. Group 1

Claims (1)

[Claims] (1) Average layer thickness: 0.2 to 20 μm on the surface of an aluminum nitride sintered substrate having a surface oxidation layer with an average layer thickness of 0.2 to 20 μm.
A semiconductor device substrate with excellent heat dissipation properties formed by forming a silicon oxide layer with a thickness of 0.05 to 5 μm.