Watermarks: Generation, Control, and Removal
After dilute HF cleaning, when a wafer is rinsed and dried naturally stains arise on the parts where there were water droplets. These are called watermarks or drying spots. During the typical wafer drying process in semiconductor manufacturing, watermarks are generated for a variety of reasons. In spin-drying, it has been reported that they are generated between the lines and in U- and V-grooves. Watermarks become masks in successive etching processes and hinder the film from depositing or forming normally, and they damage several device characteristics. Therefore, in the semiconductor fabrication process, how to reduce the number of watermarks to zero is an issue of wafer cleaning and drying technology.
KeywordsNitride Isopropyl Alcohol Isopropyl Polysilicon
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