Early detection test for identifying defective semiconductor wafers in a front-end manufacturing line

Abstract

A method and apparatus for identifying defective partially manufactured semiconductor wafers in a manufacturing line is described, wherein defects caused by silicon erosion created by over-etching the wafer can be detected. The method described herein is based on an in-line test of selected structures, such as FETs, located in the kerfs that surround the integrated circuit chips. Leakage current between the gate and the source-drain region is measured at FETs in each kerf. Based on the measurement, a leakage current map is created and compared to a standard map. In accordance with this comparison and to the distribution of patterns of leakage currents, it is determined whether or not the wafer is defective. This determination is performed in the kerfs after formation of the gate and source-drain regions, and prior to the wafer being completed. By detecting defective wafers at an early stage, considerable manufacturing resources are saved.