>Dear MEMS community, > Has any one used metal on SU-8 photoresist. We are having problems metal sticking to SU-8. >I would appreciate any inforamtion on it is passed on. >Regards, >Padmaja >Padmaja Ramadas (972)-927-1108 (w) >Texas Instruments Incorporated (972)-995-7785(fax) >P.O. Box 655012 ramadas@ti.com >M/S 945 >Dallas, Texas 75265 > > > Dear Sir, It makes now 2 year and a half that I am working with SU8 photoepoxy (this material has partily been developed in our lab at the Swiss Federal Insitute of Technology in Lausanne) and one of the first device I have developed was a SU8 thermal flow sensor with integrated metal resistors, depositied on the photoepoxy. If the SU8 is polymerised, there should be no major problem of sticking.All the metal depostions I have done so far have been done by evaporation, but I think it should be the same thing can be done with a sputtering machine. I first use a chromium layer of about 20 to 50 nm (not more!) in order to improve the adhesion. Than I can deposite metals such as gold, copper, aluminium, etc with thicknesses of more then 1 micron. These metal layers can also be patterned in a standard photolithographic way (no lift-off technology). If the SU8 is polymerized, then you can expect several problems, especially when you want to pattern the metal with for example the help of a postive photoresist. In fact when you put your wafer on a hot-plate or inside oven to make the softbake of the photoresist, the non-polymerized SU8 will become soft and deforms the metal layers. I have notice that there is however one case in which the metal don't stick to well on the SU8. It happens when you have a non-polymerized SU8 layer covered with a metal layer on which you have deposited a second SU8 layer.This last layer is polymerized. Now when you develop and 'wash' away the nonpolymerized SU8, the metal might not stick on the upper polymerized SU8 layer. For this case we are now trying to develop a modified version of the SU8 which is supposed to have better sticking properities. I hope this helps you. Should you have any more questions, please contact me. We are now creating a new company where we want to commercialize SU8 photoepoxy products and service. If you are interested, we would be pleased to collaborate with you. Best regards, Dr Louis J. Guerin **************************************************** Dr Louis J. Guerin Institute for Microsystems EPFL- Swiss Federal Institute of Technology Lausanne CH-1015 Lausanne tél: (+41 21) 693 5857 fax: (+41 21) 693 6670 email: louis.guerin@epfl.ch **************************************************** * visit our WEB page on URL: http://dmtwww.epfl.ch/ims * * * * visit our SU8 WEB page on URL: * * http://dmtwww.epfl.ch/ims/micsys/subtopics/projects/su8/EPON.html * ****************************************************