Coverglass Bonding for Dirt Intensive Mask
Original Publication Date: 1978-Jan-01
Included in the Prior Art Database: 2005-Feb-20
A mask for projection printing wafers or other masks can be made insensitive to dirt by bonding a coverglass over the mask pattern such that contamination on that external coverglass surface is out of the focal plane and does not print on the wafer. This article describes a technique for coverglass bonding which meets the specific requirements of a bubble-free adhesive layer and an ultraflat coverplate surface which is parallel to the flat mask pattern and at a reproduceable height above it.