Semiconductor gettering process using backside chemical mechanical planarization (CMP) and dopant diffusion

摘要

A gettering process for semiconductor manufacturing is disclosed. The gettering process is performed after device formation and after a protective layer such as (BPSG) or (PSG) has been applied to the front side of a semiconductor wafer. The gettering process includes thinning and roughening a backside of the wafer using chemical mechanical planarization (CMP). During the (CMP) dislocations are formed which function as a trap of mobile contaminants. Additionally a gettering agent such as phosphorus is deposited and diffused into the backside of the wafer. The wafer can then be annealed for driving in the gettering agent and segregating mobile contaminants in the wafer at gettering centers formed at the dislocations and at gettering agent sites within the wafer crystal structure. The annealing step may also function to reflow and planarize the (BPSG) or (PSG) protective layer.