JPH01308893A - Tungsten paste - Google Patents

Abstract

PURPOSE:To obtain a tungsten paste capable of remarkably improving the bonding strength to AlN, by adding an organic vehicle and an additive containing Y2O3, Al2O3 and AlN to tungsten powder. CONSTITUTION:The objective tungsten paste is composed of (A) an additive containing 0.5-80.0wt.% of Y2O3, 0.5-50.0wt.% of Al2O3 and 0.5-60.0wt.% of AlN, (B) tungsten powder and (C) the remaining part of an organic vehicle. The amount of the component A is 0.5-10.0wt.% based on A+B. An AlN substrate having excellent heat-radiation property can be effectively metallized with the tungsten paste to enable the improvement of the density, speed and output of a semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to improvements in tungsten pastes used to metallize aluminum nitride (AI!N) substrates.

[Conventional technology]

BACKGROUND ART In order to cope with the increase in heat generation due to higher density, higher speed, and higher output of semiconductor devices, substrate materials with excellent heat dissipation are required. A1. has been commonly used as a substrate material with excellent heat dissipation properties. A substrate consisting of /IN instead of O is attracting attention.

However, in order to use it as a substrate on which a semiconductor device is mounted, a technique for metalizing the substrate surface must be established before the problem of heat dissipation is addressed. As a metallization method for A2N substrates, Ajl! uses tungsten paste made by mixing tungsten powder and an organic vehicle. A method of printing on an N green sheet and firing it is known.

(Technical problem to be solved by the invention) However,
When a so-called tungsten-only paste containing only tungsten powder and an organic vehicle is used, it is difficult to obtain sufficient bonding strength between AffiN and tungsten because AlN has poor wettability with metal.

Therefore, an object of the present invention is to provide a tungsten paste that can obtain sufficient bonding strength with AlN.

[Means for solving technical problems]

The tungsten paste of the present invention has Yx O! 0.5
~80.0 wt%, Affixes 0.5~50.0
Additives containing 0.5 to 60.0 wt% of AiN and 0.5 to 60.0 wt% of AiN to the tungsten powder,
It is characterized in that it is added in an amount of 10.0% by weight, with the remainder being an organic vehicle.

[Function and Effect of the Invention] The inventor of the present application has found that A when using a tungsten-only paste consisting only of tungsten powder and an organic vehicle.
Taking into consideration that it is not possible to obtain sufficient bonding strength for the IN substrate, we mixed various additives into the paste and conducted intensive studies, which resulted in Yz Os, A j! It has been found that good bonding strength can be obtained by mixing xOs and 80N in the above proportions. The present invention was made based on this knowledge.

As is clear from the examples described below, according to the present invention,
If the above additives are added to the tungsten powder, the total of both is 0.
．． Since it is contained in an amount of 5 to 10.0% by weight, it is possible to dramatically increase the bonding strength to AlN compared to the case where a conventional paste containing only tungsten is used. Therefore, it is possible to effectively metallize the AlNM plate, which has excellent heat dissipation properties, so that it becomes possible to respond to higher density, higher speed, and higher output of semiconductor devices.

[Explanation of Examples]

AIN made by adding 3% by weight of YgOs as a sintering aid
A green sheet was prepared. In addition, a tungsten paste for metallization was prepared by mixing tungsten powder and additives in the proportions shown in Table 1, and adding the required amount of organic vehicle.

Apply the above tungsten paste for metallization on the surface of the AIN green sheet in the shape of a disk with a diameter of 3IIIm,
Dry. After that, the binder in the green sheet and the organic vehicle in the paste are scattered, a binder removal process is performed, and then the AIN with the metallized layer is baked at a temperature of 50°C for 5 hours in a non-oxidizing atmosphere. A sintered substrate was obtained.

Ni is applied to the metallized layer on the second sintered substrate by electroplating.
l was formed. Furthermore, a copper wire with a diameter of 2 mm was soldered onto N1Ji4 to obtain a test sample.

When the wire of the above test sample is pulled, the wire becomes AI! .

The tensile strength when removed from the N substrate was measured.

The measurement results are also shown in Table 1. Table 1 also shows the resistance values of the metallized layers.

(Margin below) Table 1 ・* indicates a sample outside the scope of the present invention.

- All [%] in the table represents [weight %].

(Left below) As is clear from Table 1, sample number 1,6゜7.12
,13,18,19.24,25,30°31.36,
37, 42, 43.4B, and 49.54, when the additive content is less than 0.5% by weight or exceeds 10% by weight, the tensile strength is 2.0kg or less. became. Further, when the proportion of the additive exceeded 10.0% by weight, the resistance value of the metallized layer also increased to 50 μΩ·cm or more.

In contrast, samples using metallizing pastes within the scope of the present invention (sample numbers 2-5.8-11.14-
17.20~23.26~29°32~35.38~4
1.44-47. 50-53), the tensile strength is 5.
It can be seen that it is more than Qkg/m''.

On the other hand, when the composition of the additives added to the metallizing paste is outside the range of the present invention, as in the case of the first poison sample number 55.56.57, the tensile strength is 2.5%. Qkg/v
It can be seen that the value is less than a".

From the above results, YtOy is 0.5 to 80.0Xlif
%, le, O, o, 5-50. OmFJ9A and/
Additives containing 0.5 to 60.0% by weight of IN
It can be seen that by including 10.0% by weight, the bonding strength with AlN is dramatically increased.

In the above example, the tungsten paste for metallization was printed on the surface of the /IN green sheet, but after printing the tungsten paste for metallization, the green sheets were stacked, and the metallization layer was positioned inside the laminate.
The tungsten paste of the present invention can also be used in a method of forming a metallized layer in an AIN sintered body by compressing and firing stacked green sheets, and a stable internal conductor can be formed.

Claims (1)

[Claims] A tungsten paste for metalizing an AlN body, containing 0.5 to 80.0% by weight of Y_2O_3 and A
Additives containing 0.5 to 50.0% by weight of l_2O_3 and 0.5 to 60.0% by weight of AlN are added to the tungsten powder in a total amount of 0.5 to 10.0% by weight. , the remainder consisting of an organic vehicle.