1.7　Summary

Advanced polyimide films have been extensively used in electrical insulation， microelectronic and opto-electric display manufacturing and packaging， aerospace and aviation industries， etc.， due to their excellent combined properties including thermal dimensional stability， high mechanical strength， modulus， and toughness， high electrical insulating performance， and low dielectric constant and dissipation factor， etc. There are two pathways in polyimide film production： one is the thermal imidization， and the other is chemical imidization. The polyimide film-forming processes are very complicated chemical reactions and physical changes. The precise control of the chemical reactions and physical changes are the key issues in the production of high-quality advanced polyimide films. There are obvious effects of chemical structures on the combined properties of the polyimide films. The surface modifications of polyimide films by plasma technology are also important for electronic applications. Many high-performance and functional polyimide films have been developed in recent years， including the low-thermal-expansion and high-modulus polyimide films， corona-resistant polyimide films， etc.