Mask-Handling Pneumatics Control
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
Mask scratching and contamination in semiconductor chip manufacturing are reduced by a modified pneumatics control which permits the mask to be received and fully positioned horizontally before the mask is moved vertically and clamped into its final operating location. Compressed air from supply 1 is directed to valve 2 which provides an output on line 3 before it provides an output on line 4. Mask home clamp cylinder 5 is actuated to move mask 6 in response to metered air on line 3 to position the mask fully while being spaced apart from the mask reference ring (not shown). Clamp-in cylinder 7 is actuated by line 4 after the delay afforded by valve 2 to drive the mask home against the mask reference ring without any transverse movement between mask and ring which might tend to scratch the mask.