A Study of the Microstructure, Texture and Sputtering Properties of 5N High-purity Aluminum Target

摘要

This investigation studies the effects of the microstructure and texture on the sputtering properties of a high purity aluminum target. In this study, the purity of aluminum target is as high as 99.999% (5N). The 5N aluminum ingot first underwent hot-rolling and heat treatment, and was then cut into different kinds of test specimens. A series of microstructural observations, texture analyses and sputtering experiments were conducted to study the properties of the 5N aluminum target. The research results show that the 5N aluminum target experiences dynamic recovery during hot-rolling due to its high stacking fault energy. Heat treatment at the proper temperature could help the 5N aluminum target complete recrystallization, enabling the target to possess a fine grain and cube texture. In addition, since the purity of the aluminum target is as high as 99.999%, any slight temperature deviation during hot-rolling and heat treatment would affect the microstructure and texture of the aluminum target. The results of the sputtering experiments show that any undesirable microstructure or texture of the aluminum target would influence its sputtering rate and the properties of the aluminum thin film after sputtering. A fine grain and cube texture are beneficial to the 5N aluminum target by permitting an increased sputtering rate, and allowing the aluminum thin film to possess a low electrical resistance after sputtering. Moreover, hillocks would appear on those aluminum thin films produced by an aluminum target with low sputtering rate at lower temperature, causing short circuits in the LCD panel. Therefore, to improve the sputtering rate of 5N aluminum target in order to obtain aluminum thin film with a low electrical resistance and excellent anti-hillock properties, the temperature of the hot-rolling and heat treatment must be controlled precisely to ensure that the aluminum target possesses a fine grain and cube texture.