Patent ID: 8846500
Filing Date: 2014-09-30
Classification: H01L

Abstract:
1. A method for gettering a semiconductor wafer comprising: providing a semiconductor substrate having a first major surface and an opposed second major surface, the first major surface configured for forming semiconductor devices; depositing an amorphous layer on the second major surface at a first temperature and a first pressure, where the amorphous layer has a first layer stress value; depositing a polysilicon layer on the amorphous layer at a second temperature and a second pressure, where the polysilicon layer has a second layer stress value, where upon depositing the polysilicon layer the amorphous layer crystallizes changing the first layer stress value to a new first layer stress value, where the new first layer stress value is a tensile stress value, and the second layer stress value is a compressive stress value; the new first layer stress value and the second layer stress value combine to form a gettering structure having a residual stress value configured to reduce warpage of the semiconductor wafer; and exposing the semiconductor wafer to an elevated temperature to getter unwanted impurities away from a region proximate to the first major surface towards the second major surface.