Patent ID: 6254686
Filing Date: 2001-07-03
Classification: C23C,C30B

Abstract:
A deposition apparatus for depositing a layer of material on a wafer, said apparatus comprising:a deposition chamber having a side wall;a susceptor plate in a first plane within said deposition chamber, said susceptor plate extending across said deposition chamber to divide said deposition chamber into an upper portion which is above the top surface of the susceptor plate on which a wafer is supported, and a lower portion which is below the back surface of the susceptor plate;a preheat ring in said first plane and surrounding said susceptor plate, said preheat ring separated from said susceptor plate by a gap having a first cross-sectional area;a vent extending from said lower portion of said deposition chamber liner to said exhaust passage, said vent having a second cross-sectional area; andan exhaust passage extending from said upper portion of said deposition chamber through said sidewall;wherein said second cross-sectional area and said first cross-sectional have a relative relationship which allows heated purge gas in the lower chamber to prevent deposition gas in the upper portion of the chamber from flowing through said gap and to provide a sufficient amount of heated gas into said exhaust passage so that deposition gas in said exhaust passage does not condense therein.