Design of HDP CVD ceramic liners for plasma sources

Summary form only given, as follows. A successful development of a good ceramic liner design for plasma assisted CVD process requires a complete understanding of the temperature distribution on the liner. During the development of two aluminum oxide liners, cracking was observed near the bottom of both ceramic liners which represents the point, of the highest power density major cracks were observed to run circumferentially across the cylindrical liners and were believed to be caused by excessive tensile stresses resulting from either temperature gradients or/and temperature transients induced by various operating conditions. Because of premature failure, a detailed characterization of the temperature profile was carried out on two ceramic liners using a combination of measurement and numerical modeling. Numerical modeling was performed using computational fluid dynamics and heat transfer and stress finite element analysis. Also a plasma fluid model was developed using a CFD-ACE+ software package and pointed out the formation of an off-center ionization rate peak. This peak that was located near failure zone. Results were in turn used to obtain a better understanding the cause of the premature failure. A probabilistic failure assessment approach was used to explain the cause of the failure. Design improvement concepts were suggested in terms of more stringent material parameter and better liner cooling to alleviate any future potential failure.