Research on Grain Refinement Process and Microstructure of Ultra-High Purity Copper Used for Integrated Circuit

Abstract

In this paper, the deformation and annealing process of ultra-high purity copper used for Ultra large-scale integration (ULSI) have been investigated. The evolution of grain size and texture during deforming and annealing were analyzed. The results show that the coarse cast structure can be efficiently eliminated by multiple forging and the grain size can be refined initially. Ultra-high purity copper with cold rolling begins to recrystallize at a temperature of 150°C. Especially, when the cold rolling deformation is 80%, the average grain size is about 17.9μm after optimized annealing. The typical rolling textures after deformation are not strong and a large number of low-angle grain boundaries are found. After annealing, the rolling texture and recrystallization texture come to co-existence. The texture distribution is uniform without strong grain orientation and high-angle boundaries demonstrate in the microstructure.