TEOS oxide film 두께 profile의 하부막 의존성

Abstract

The TEOS oxide film deposited by PECVD using tetraethylorthosilicate(TEOS) and Oxygen has studied for sublayer dependency. I observed TEOS oxide thickness profile discrepancy that thickness profile became center lower and edge higher profile on nitride sublayer than on bare Si substrate. The total ONON stack thickness uniformity in 3D NAND is key role for post photolithography and etch process. The PECVD process can produce variable TEOS oxide film thickness profile by process and hardware knobs. But TEOS oxide film thickness profile needs center higher thickness profile on bare Si substrate due to becoming center lower profile on nitride sublayer in alternating ONON 3D NAND stack. Based on nitride sublayer’s composition, center low and edge high TEOS oxide thickness film can be deposited by repulsion and attraction chemical reaction related electronegativity [3]. It results in TEOS Oxide film thickness profile discrepancy as well as deposition rate discrepancy between on bare Si substrate and on nitride in ONON stack.