Minimization of Particle Deposition on Wafers Caused by the Pressure Change in the Vacuum Chamber Through a Pressure Control Regulation Process

Abstract

In wafer etching, regular cleaning and maintenance of process chambers are necessary to reduce particle contamination of etched wafers during the wafer transfer process. Investigating alternative cleaning and maintenance is imperative. This study analyzed the number of particles falling onto a silicon wafer when the pressure difference within the process chamber was manipulated. We observed that rapid opening of the pressure control valve, which regulates the chamber’s pressure, caused contamination during wafer transport. This was particularly true when the change in the pressure ratio was considerable. The by-products near the side of the chamber’s pressure control valve were activated and transported. We verified this finding by adjusting the opening ratio of the pressure control valve (i.e., its degree of opening). We proposed that during the transition step of the etching process, this opening ratio can be controlled by regulating the process pressure through gas flow settings. This method could suppress the deposition of reflected particles originating from the turbomolecular pump’s pumping line on wafers, thereby minimizing the contamination of wafers.