Welding method of tungsten target assembly

Abstract

The invention provides a welding method of a tungsten target assembly, which comprises the following steps of: providing a tungsten target blank and a copper back plate between which an intermediate layer is additionally arranged; placing the tungsten target blank, the intermediate layer and the copper back plate in a vacuum sheath, so that the intermediate layer is positioned between the tungsten target blank and the copper back plate, and the vacuum sheath is placed in welding equipment; welding materials to be welded together by a hot isostatic pressing process to form the tungsten target assembly; and after the ompletion of welding, carrying out cooling, and removing the vacuum sheath to obtain the tungsten target assembly. By additionally arranging the intermediate layer between the tungsten target blank and the copper back plate and welding the tungsten target blank and the copper back plate together by utilizing the hot isostatic pressing process, the large-area welding can be realized, and the surface of the welding material can be prevented from being oxidized because the whole welding process is in a vacuum environment; and in addition, in the formed tungsten target assembly, the bond rate and the bond strength of the tungsten target blank and the copper back plate are higher, and the deformation is small after the tungsten target blank and the copper back plate are welded together.

Description

technical field [0001] The invention relates to the field of manufacturing semiconductor sputtering targets, in particular to a welding method for tungsten target components. Background technique [0002] In the semiconductor industry, the target assembly is composed of a target that meets the sputtering performance and a back plate that can be combined with the target and has a certain strength. The back plate can play a supporting role when the target assembly is assembled to the sputtering base, and has the effect of conducting heat. For example, metal tungsten (Co) can be selected as the target material, and copper or copper alloy material with sufficient strength, high thermal conductivity and high electrical conductivity can be selected as the back plate to form the target component. [0003] During the sputtering process, the working environment of the target assembly is relatively harsh. For example, the ambient temperature of the target assembly is relatively high...

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Problems solved by technology

[0006] For the target assembly composed of tungsten target and copper back plate, since the melting point of tungsten is 3407°C and the melting point of copper is 1084°C, the melting points of the two materials are quite different, and the existing welding equipment cannot realize large-scale welding. Therefore, it is not suitable to weld the tungsten target and the copper back plate together by welding; the tin solder or indium solder used in the brazing process has a low melting point (less than 250 ° C), so that when the tungsten target is welded by brazing When the material and the copper back plate are welded together, not only the bonding strength between the two is low (less than 70Mpa), but also the high temperature environment will melt the solder, making the sputtering process impossible; since tungsten is a relatively stable metal, Copper is a metal that is easily oxidized. When the temperature in the air exceeds 200°C, the welding surface between the tungsten target and the copper backplane will be oxidized, so that the atoms at the welding surface of the tungsten target and the copper backplane cannot be oxidized. Diffusion results in poor weld tightness of the target assembly and is therefore not suitable for welding the tungsten target to the backplate by diffusion welding

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