Measurement techniques of sheet resistance on copper defects after chemical mechanical polishing

Chemical mechanical polishing (CMP) has been widely used in removing overburden copper (Cu) interconnects to realize global plannariztion. However, Cu defects including void, dishing, and erosion etc. always accompany after CMP process to influence semiconductor manufacturing yield. In this study, an accurate measurement technique of sheet resistance on erosion defect after Cu CMP is investigated by estimating Cu metal line resistance and applying some mathematic equations to calculate the thickness of erosion defect. By way of the results, the accuracy of this measurement model of erosion defect is high and the error is smaller than 100 Å. In addition, it is also suitable for exploring different wafer conditions such as Cu metal line widths and pattern densities, even process recipe. Therefore, this novel method benefits greatly on monitoring insitu the degree of erosion defect after CMP to avoid a large number yields coming down.