How thick is the gold seed layer, it should be a least 200nm thick for good current spreading. How long is the O2 plasma clean, you may want to extend it to ensure that there is no scum on the gold surface you are trying to plate. What kind of gold bath do you have sulfite or cyanide based? How many electrical contacts are you using? Do you have a low resitance contact? What current density are you using? Rick -----Original Message----- From: Sunshine Littlecreek [mailto:sunshine.littlecreek@gmail.com] Sent: Thursday, June 22, 2017 7:32 AM To: mems-talk@memsnet.org Subject: [mems-talk] Problem with SU-8 Thick film Hello, I’m working with SU-8 2025 and 2075, 100 um - 500 um thick on top of gold. My features are 20 um - 300 um wide. When I try to electroplate the features, some of them don’t plate. Here’s my process: Clean substrates (acetone, IPA, diH20 10 minutes each), dehydrate for 30 min. Spin Omnicoat at 3000 rpm, bake for 1 min at 200 C. Spin SU-8 at 1000 rpm, soft bake for 7 min at 65 C, ramp to 95 C, bake for 20 min (thinner films)-45 min (thickest films). Expose with UV 3 cycles of 270 mJ/cm^2 and post exposure bake : 5 min at 65 C, 15 min at 95 C up to 25 min for thickest films. Development is done using MicroChem SU8 Developer on a shaker plate (usually about an hour). When I rinse with IPA and diH20, no white haze forms, so it should be fully developed. Omnicoat gets developed in an O2 plasma chamber at 100 W. I’ve looked around the web, and tried some of the suggestions like using a sonicator (developed features quickly, but resulted in sheets of SU8 coming off taking features with it), rinsing more frequently, and eliminating the PEB (SU8 dissolved in developer), but I haven’t had better outcomes. I do a visual inspection using a stereoscope to check if the bottom looks clean, which it usually does. However, when I electroplate, not all of the features plate or plate evenly. I’ve gone from having no plating at all (resulted in higher exposure and longer development times being used) to partial plating. I need to get all my features to consistently plate across all features. Any ideas or suggestions would be greatly appreciated. Thank you, Sunshine Littlecreek _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk ________________________________ Notice: This email and any attachments may contain proprietary (Draper non- public) and/or export-controlled information of Draper. If you are not the intended recipient of this email, please immediately notify the sender by replying to this email and immediately destroy all copies of this email. ________________________________ _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk