Hello, I suggest you try an adhesive plastic foil, which is typically put on using heat and pressure. This product is often times used on the wafer prior to backside thin down or prior to wafer sawing. Good luck. -----Original Message----- From: JARED_LERA/electronics_singlekh2_kihung_grp0@gp_manTo: MEMS@ISI.EDU Date: Friday, November 27, 1998 8:55 PM Subject: Defects due to photo patterning >Dear colleagues: > > I am having a problem with making SiN membranes. When I pattern the backside of the >wafer the SiN coating on the front side gets all scratched up due to the chucking and > >handling used in our photo lithography process. These scrathes then cause our membranes >to shatter when the SiN layer is exposed after the silicon is all etched away. I have >tried to place a thick oxide layer (2 microns) over the SiN to protect it during the >back side patterning. But still many defects appear. Is there any kind of chucking machine > >that protects the side which is being handled? > > >Thanks in advance for you help, > > >Jared Lera >Semiconductor R&D >Samsung Electronics > >