MASK DEFECT PRINTABILITY AND WAFER PROCESS CRITICAL DIMENSION CONTROLAT 0.25 MU-M DESIGN RULES

In this paper, the effect of mask defects in a wafer process is studie d by taking into account the wafer process critical dimension (CD) var iability. We found that trade-offs between the wafer CD control specif ication, the actual wafer CD controllability, and the mask defect size requirement exist. We also developed a new statistical explanation fo r the printable mask defect size which is related to the wafer process specifications and the actual wafer process CD controllability. Based on our statistical assessment, any small mask defect is printable wit h a given failure rate. The advantages of our data analysis methods ca n be summarized as follows. 1. The printing effect for a given mask de fect size can always be extrapolated even though that defect size is n ot present on the mask. The defect printability can be redefined witho ut any additional data collection when the process control or the proc ess specification is changed. 3. Information relative to data collecti on is maximized. 4. The defect printability risk analysis is tied to t he process control and the process specifications.