Photodefinable Epoxycyclohexyl Polyhedral Oligomeric Silsesquioxane

photodefinable dielectric was developed using epoxycyclohexyl polyhedral oligomeric silsesquioxanes (POSS) and a photocatalyst. POSS is a hybrid organic/inorganic dielectric which has favorable mechanical and chemical stability for use as a permanent dielectric in microfabrication. Sharp, 10 μ m wide features were formed from POSS using 365 nm radiation. The optical contrast was 1.51. POSS films were thermally stable to 350°C and demonstrated chemical stability in a variety of solvents and oxidants. The polymer film had an elastic modulus of 5.3 GPa and a hardness of 0.64 GPa. The POSS had high etch selectivity compared with organic films for pattern transfer.