Submicron connection layer and method for using the same to connect wafers

摘要

A submicron connection layer and a method for using the same to connect wafers is disclosed. The connection layer comprises a bottom metal layer formed on a connection surface of a wafer, an intermediary diffusion-buffer metal layer formed on the bottom metal layer, and a top metal layer formed on the intermediary diffusion-buffer metal layer. The melting point of the intermediary diffusion-buffer metal layer is higher bottom metal layers may form a eutectic phase. During bonding wafers, two top metal layers are joined in a liquid state; next the intermediary diffusion-buffer metal layers are distributed uniformly in the molten top metal layers; then the top and bottom metal layers diffuse to each other to form a low-resistivity eutectic intermetallic compound until the top metal layers are completely exhausted by the bottom metal layers.

主权项

1. A method for using a submicron connection layer to connect two wafers, comprising:
Step (a): providing a first wafer and a second wafer; Step (b): forming a connection layer on a connection surface of each of said first wafer and said second wafer, wherein said connection layer comprises a top metal layer, an intermediary diffusion-buffer metal layer and a bottom metal layer, and wherein a melting point of said intermediary diffusion-buffer metal layer is higher than melting points of said top metal layer and said bottom metal layer, and wherein materials of said top metal layer and said bottom metal layer form a eutectic phase; and Step (c): bonding said connection layer of said first wafer to said connection layer of said second wafer, wherein said top metal layers, which are separated from said bottom metal layers by said intermediary diffusion-buffer metal layers, are joined to each other in a liquid state to melt; next said top metal layer and said bottom metal layer of each of said first wafer and said second wafer are melting; said intermediary diffusion-buffer metal layers are distributed uniformly into said top metal layers and said bottom metal layers having melted; then said bottom metal layer and said top metal layer of said first wafer diffuse to each other until said top metal layer of said first wafer is completely exhausted by said bottom metal layer of said first wafer, and said bottom metal layer and said top metal layer of said second wafer diffuse to each other until said top metal layer of said second wafer is completely exhausted by said bottom metal layer of said second wafer to form a eutectic intermetallic compound having said intermediary diffusion-buffer metal layers uniformly distributed in said eutectic intermetallic compound.