As far as my understanding goes HMDS bonds to oxygen. HMDS is most helpful
on SiO2 or Si substrates where HMDS can bond to oxygen. HMDS is only helpful
on a moisture free surface (Si/SiO2). HMDS in vapor prime (on si/SiO2) is
more helpful. Hence I don't think it would be that chemically helpful to use
HMDS on gold or other metal substrates. In some cases HMDS might make the
surface worst. There is another way that HMDS might be helpful on metal
substrates, without forming a chemical bond, is by forming a hydrophilic
surface. It is possible that HMDS forms a hydrophilic layer on gold
substrate hence enhancing the sticking of  photoresist to the gold
substrate. This means to ensure that HMDS really helps it would be good to
measure the contact angle between resist and HMDS coated gold surface.
I hope this information is helpful.



-----Original Message-----
From: Todd Green [mailto:[email protected]]
Sent: Tuesday, February 16, 1999 2:48 AM
To: [email protected]
Subject: HMDS on metals


Is HMDS useful as a resist adhesion promoter on substrates other than
silicon? We use HMDS before applying resist to a gold coated wafer and I
was wondering if this would have any benefit on gold-resist adhesion.

Thanks,


Todd