Wafer particle standards for scanner calibration and defect reduction

Detection of particulate contamination on semiconductor wafers is a critical issue in semiconductor device manufacturing. This paper describes some recent development in particle deposition technology for preparing NIST traceable particle wafer standards for wafer scanner calibration and evaluation. The application of such particle standards for wafer scanner calibration and defect reduction in the semiconductor device fab is described. Particular attention is paid to the detection of contaminant particles near the lower size limit of the scanner and the effect of particle material and refractive index on the lower limit of the wafer scanner. Some results on the application of standard process particles for measuring cleaning efficiency of wafer surface cleaning processes is also described.