THE ANISOTROPIC PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION SIO2 SPIN-ON GLASS PROCESS FOR 0.35 MU-M TECHNOLOGY/

A new plasma enhanced chemical vapor deposition (PECVD) oxide is propo sed to form an anisotropic SiO2 film with ultra low sidewall step cove rage for the intermetal dielectric (IMD) process. This oxide is named anisotropic plasma oxide (APO). In the APO technology, the anisotropic deposition is achieved by reducing the O2/TEOS (tetraethylorthosilica te) feed ratio in current PECVD process. The APO sidewall step coverag e can be lowered to 20% compared to 65% for the conventional PECVD oxi de. Reflective index, measured by ellipsometry method, indicates that the APO film is Si-rich. High deposition rate and low film stress show the APO is suitable to the IC production. This technology is successf ully applied to the 0.5 mum 16 M dynamic random access memory (DRAM) p roducts and is expected to apply to 0.35 mum ULSI technology.