PAD-Dry

The PAD-Dry performs the last step in the WSPS process. It is essentially a preparation step for subsequent TXRF analysis. As a modular part of the WSPS system it is designed for fully automatic operation and wafer handling. The drying process is optimized for throughput and production of TXRF compatible droplet residues. In order to meet the cycle time of the WSPS the PAD-Dry features a short drying time of 13 minutes. At the same time the drying conditions are smooth enough for creating small and homogeneous droplet residues.

After scanning with the PAD-Scan the droplets are deposited on a silicon wafer, which is transferred to the PAD-Dry for further processing. The droplets are dried with the PAD-Dry by evacuationg the chamber and heating the wafer stage. Vacuum and temperature are chosen for optaining a TXRF compatible residue shape.

For TXRF the diameter of the dried droplet should not exceed the detector area. The diagram indicates that the maximum diameter is about 12 mm. Typical TXRF detectors have a diameter of 8 mm.