Molybdenum Mask Removal Tool
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
Molybdenum mask life may be shortened considerably due to adverse bending and creasing of the masks as they are manually removed from the silicon wafers by the operator during wafer processing. The mask removal tool described in this article significantly reduces both mask damage and wafer breakage by separating the mask from the wafer through the application of an evenly distributed force around its circumference. As shown in Fig. 1, wafer 1 attached to Moly mask 2 (by the PbSn metal evaporation process which forms individual solder pads on chips) is vacuumed down by means of a full vacuum wafer chuck 3 on support plate 4. Moly mask 2 directly above wafer 1 is vacuumed down by means of a vacuum ring 5, as shown.