Advanced material for process performance in plasma process

For the IC chip production, the process stability is always the vital for the quality control in the plasma dry etching process. However, we found E/R on SiN always showed down-trend with the increasing of processed wafers in the aggressive process, such as HBr and Ch, it really brought a lot of trouble. The feedbacks from on-site productions (more than two customers) all are suffering from etch rate drifting issue. That need we are look into new advanced material to resolve the issue. In both ICP (Inductive coupled plasma) and CCP (Capacitive coupled plasma) etch chambers, the chamber liner is designed to encapsulate the plasma inside the plasma reactor and its big surface is contacted with plasma during the plasma etching process. The variations of the composition and properties on the liner surface will sensitively affect the plasma etching process stability. Usually, the chamber liner is manufactured by Al alloy, while the liner surface is coated by plasma sprayed Y2O3 or other plasma resistant coating, to maintain the process stability and to extend the service life time. The present work investigated the impacts of the plasma chemistry and process stability on SiN etch rate in plasma etching. It was found that the variations of the composition and properties on the liner surface will sensitively affect the plasma etching process stability. So it suspects that if process recipe is aggressive enough and then process kit with high porosity and rough surface will be bad for process stability. Especially, as for PS coated kits, the feedback from other customers is suffering from etch rate drifting issue. AMEC study the productive issue and develop an advance coating material HD YO (high density and smooth surface coating) to improve the process stability.