Ester-type photosensitive polyimide precursor with low thermal expansion coefficient

For an ester-type photosensitive polyimide precursor of low thermal expansion coefficient, the oxygen concentration in the curing process and the molecular weight of the polyimide precursor were found to control the properties of the polyimide. The effects of these factors on the thermal expansion coefficient, tensile strength, and modulus of polyimide film were investigated. Based on these results, a photosensitive polyimide with low thermal expansion coefficient, called the PIMEL TL-series, was developed. Crack and delamination free multilayers were successfully achieved using this newly developed product