The WSS2150W Wafer Weight Handling System allows the weight of each wafer to be determined before sorting it into a small number of clamshell or half-height open cassettes, and it is designed in a 6-inch size. Wafers are transferred from open cassettes to clamshells for spin-rinse-dry (SRD) process. Determine the weight of each wafer in the clamshell for pre-roughing, wafers are sorted into clamshell/open cassettes according to their range of weight loss. After repeating the SRD process, all wafers will be transferred back to the open cassette once all wafers reach the required weight. ​