AMAT P-5000 CVD-clean optimization project

The Applied Materials (AMAT) P-5000 Plasma Enhanced Chemical Vapor Deposition (PECVD) systems use a plasma-enhanced tetraethoxysilane (TEOS)/oxygen chemistry to deposit an undoped silicon glass (interleave dielectric) film on 200 mm wafers. After each TEOS deposition cycle, the reaction chambers require an in-situ clean to remove residual dielectric materials from the electrodes and chamber walls. Excessive chamber cleaning causes unnecessary process-kit wear. This reaction is caused by the chemical and mechanical attack of the reaction by-products on process-kit parts after the TEOS deposition residues have been cleared. IBM's continued emphasize on cost reduction, environmental concerns and limited availability of chamber-cleaning gases prompted this joint project with Applied Materials, which focused on identifying areas where costs associated with gases used for post-deposition cleaning could be decreased and the time between process-kit replacements increased. This paper describes the tests conducted with an RF metrology system (RFMS) manufactured by Fourth State Technology (FST), Austin, Texas, to determine the optimum clean times for various oxide films and the minimum flows required for efficient post-deposition chamber cleaning. As a result of this experimentation, process changes were made that reduced clean gas consumption and chemical cost. Additional savings were realized by reducing wear on the reaction chamber hardware and achieving longer meantime between process-kit replacements.