Research on the Process and Performance of Low Dielectric Constant Photosensitive Polyimide

Photosensitive polyimide （PSPI） has important applications in high-density integrated circuits and advanced packaging. Reducing the dielectric constant and dielectric loss of PSPI can effectively reduce signal delay and signal loss during high-frequency high-speed transmission. This paper systematically studies the structural design of low-dielectric-loss photosensitive polyimide and the effects of its light curing and thermal curing processes on its dielectric properties. By manipulating the fluorine-containing groups and alicyclic structures， a series of PSPI with low dielectric constant and low dielectric loss were designed. It reveals the different impacts of various thermal curing temperatures （200~350 ℃） and different processing techniques such as post-light curing and then thermal curing on the dielectric constant and dielectric loss of PSPI. Experimental results show that with high-temperature thermal curing alone， the dielectric constant （Dk） and dielectric loss （Df） of PSPI decrease with increasing curing temperature （Dk=3.1~2.6， 200~350 °C）， while samples that are light cured and then thermally cured can also achieve low dielectric constants （Dk=3.0~2.4， 200~350 ℃） and low dielectric loss， while maintaining excellent mechanical properties and thermal stability. This study provides a theoretical basis for the structural design and application of high-performance low-dielectric-loss PSPI.