Copper-copper metal thermal pressing bonding method

Abstract

The invention provides a copper-copper metal thermal pressing bonding method. The method at least comprises the following steps: first of all, providing a first wafer to be bonded and a second wafer to be bonded, wherein the first water comprises a first substrate, a first passivation layer and a first Ti-Cu alloy film, and the second wafer comprises a second substrate, a second passivation layer and a second Ti-Cu alloy film; then, performgin thermal pressing bonding on the surface of the first Ti-Cu alloy film of the first wafer and the surface of the second Ti-Cu alloy film of the second wafer; and finally, performing annealing processing in a protective gas to enable Ti atoms in the first Ti-Cu alloy film to diffuse towards the surface of the first passivation layer and Ti atoms in the second Ti-Cu alloy film to diffuse towards the surface of the second passivation layer so as to finally form Ti adhesive / barrier layers on the surfaces of the first passivation layer and the second passivation layer, and Cu atoms diffusing towards a bonding surface so as to realize bonding. According to the method provided by the invention, before the bonding, what is needed is only to respectively perform co-sputtering on the two substrates for once, such that the sputtering frequency is reduced by half, the process is relatively simple, the reliability is good, the technical cost is quite low, and finally, the Ti adhesive / barrier layer are formed through diffusion after the annealing processing, and the copper bonding effect is better.

Description

technical field [0001] The invention belongs to the field of semiconductor devices and relates to the bonding of wafers in the field of three-dimensional packaging, in particular to a copper-copper metal thermocompression bonding method. Background technique [0002] With the reduction of chip size and the improvement of integration, the traditional two-dimensional integration technology encounters an insurmountable development bottleneck. Compared with two-dimensional integration technology, three-dimensional integration technology can realize chip multi-function, improve chip integration, reduce signal delay, and reduce power consumption. Three-dimensional integration technology can generally be divided into transistor stacking, die-level bonding, die-wafer bonding, and wafer-level bonding. Among them, wafer-level bonding is the most ideal implementation form and can be used for heterojunction integration. The cost is low and the output is high. The interconnection betwee...

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Problems solved by technology

[0010] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a copper-copper metal thermocompression bonding method, which is used to solve the problems of many sputtering times and complicated processes before bonding in the prior art

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