Parylene film for sidewall passivation in SCREAM process

Trench sidewall passivation is a key step in the SCREAM (single crystal reactive etching and metallization) process for releasing suspended MEMS structures. In this paper, the parylene thin film is reported to serve as the passivation layer owing to its excellent conformality, chemical inertness, mechanical performance, and especially, low growth temperature. The deposited parylene films are characterized and the test structures are released through SCREAM process utilizing the parylene films as a passivation layer. The results show that as a passivation layer the parylene has more merits than the PECVD SiO2 film.