Instantaneous generation of many flaked particles caused by micro-arc discharge and detection method using load impedance monitoring system — Yuji Kasashima

In volume manufacture of LSI, particle contamination in plasma etching equipment is among the most serious problems [1]. The particles cause short circuit of LSI and significantly lower production yield. Mass-production equipment must be stopped for cleaning of etching chambers periodically, which gives rise to the reduction in overall equipment efficiency (OEE). Development of particle-free processes and equipment is crucially important to reduce production cost. In plasma etching for the mass production of LSI, etching reaction products adhere to the inner chamber walls, gradually forming films as wafers are processed. During the etching process, a few particles are constantly generated by flaking of the deposited films due to electric field stress that acts boundary between the inner wall and the film [2]. On the other hands, serious contamination caused by many particles sometimes abruptly occurs. This causes a number of defective LSI devices and significantly decreases the production yield and OEE. Micro-arc discharge is considered as a possible cause of the sudden generation from the situation of damages in the chamber, however, the mechanism has not been understood. In this study, to reveal the mechanism in detail, we investigate the relationship between the instantaneous generation of flaked particles and micro-arc discharge under mass-production conditions. Then, a practical detection method has been developed.