Low Temperature Curing of Polyimide Precursors by Variable Frequency Microwave

Polyimides are commonly used as a thermally stable insulator for semiconductors. To assure adequate chemical or physical properties, a layer of their precursors has to be cured in a convection oven at more than 300 °C. In this paper, we compare variable frequency microwave (VFM) heating with convection heating for curing various polyimide precursors and a photosensitive polyimide precursor. Then, we demonstrate that the use of VFM enables us to cure the precursor lower than the standard convection cure temperature while maintaining necessary film properties such as cyclization, Tg, Td, and elongation.