I would agree with Bill. I would try longer LOWER, ENERGY exposure. I dont recall if you can vary the power on the lamp. I recall the paper by Mary Long and have observed the same problem way back. Avi Laker On Wed, Jan 13, 2010 at 4:36 PM, Bill Moffatwrote: > One possibility that comes to mind. Very early technical paper by Mary > Long in the 80's on bubble formation in thick resist at exposure. 17 > microns is pretty thick. During exposure the heat of the exposure lamp > causes bubble formation inside the resist. If there is a bubble partially > on the expose section it will give a half circle in the resist line that is > developed away. Mary was at Motorola or Arizona University in Tucson when > she gave the paper. My colleague and I would have thought the problem would > have been reversed, mouse bites in the aluminum because of the reflectivity > of the aluminum. Try longer gentler exposure. Also when we got mouse bites > in aluminum we increase the prime time from 5 minutes to 20 minutes. The > lower number of hydroxyl ions on metal require longer HMDS exposure for the > same contact angle. Bill Moffat >