THE PRACTICAL USE OF CAVITATING JET FOR GETTERING IN SILICON WAFER

Gettering in a silicon wafer can be ach ieved by using a submerged water jet with cavitation, i.e., a cavitating jet. Gettering is a very important technique in semiconductor manufacturing to remove unwanted impurities from active device regions in silicon wafers. Silicon wafers used for semiconductors are inevitably contaminated during device processes. If damage is intentionally introduced into backside of the silicon wafer, unwanted impurities in the wafer are gathered into the region damage introduced. Then the surface of the wafer that is active device region is kept free from these unwanted impurities. The damage for gettering has been successfully introduced by the cavitating jet. In this paper, the gettering method by using the cavitating jet is presented. The wafer was treated by the cavitating jet for introducing backside damage. The wafer damage introduced was intentionally contaminated by the solution of Cu(NO 3)2 and was thermally treated for diffusing contaminations. In order to confirm the gettering ability of introduced damage, the etch pits on the surface that were defects caused by contaminations were observed after applying crystallographic etching to the wafer. The damage was observed before and after thermal treatment to reveal the suitable damage for gettering. The gettering ability of the damage introduced by the cavitating jet is demonstrated.