The Anisotropic Plasma-Enhanced Chemical Vapor Deposition SiO 2 /Spin-on Glass Process for 0.35 µm Technology

A new plasma enhanced chemical vapor deposition (PECVD) oxide is proposed to form an anisotropic SiO 2 film with ultra low sidewall step coverage 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 O 2 /TEOS (tetraethylorthosilicate) feed ratio in current PECVD process. The APO sidewall step coverage can be lowered to 20% compared to 65% for the conventional PECVD oxide. 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 successfully applied to the 0.5 µm 16 M dynamic random access memory (DRAM) products and is expected to apply to 0.35 µm ULSI technology.