A study of rare contamination defects come in a vacuum chamber

The pattern size of semiconductor circuits has been shrunk as technical advances continued. Defect control becomes tighter due to a decrease in defect size that affects the image printed on the wafer. It is critical to the photomask which contained a considerably shrunk circuit and ultra-high density pattern for sub – 20 nm tech devices. In this paper we group two types of rare process defects that think come in vacuum chamber contamination here we also present hypothesis defects mechanism and possible solution.