Pure Al thin film protective layer to prevent stress migration in Al wiring for thin-film transistors

The anti-stress migration property of layered structure aluminum (Al) thin films overcoated with pure Al was investigated for application of such film s as interconnect materials in large arrays of high-resolution thin-film tr ansistor liquid crystal displays (TFT-LCDs). It was found that no hillock o r whisker generation occurred in a pure Al thin film with a sputter-deposit ed fine-grained polycrystalline pure Al layer after exposure to mechanical and 300 degrees C thermal stresses. Atomic force microscopy (AFM) and cross -sectional transmission electron microscopy (TEM) analyses revealed the mor phology of the layered structure thin film and the mechanism for the preven tion of stress migration in the film. (C) 2000 Elsevier Science S.A. All ri ghts reserved.