I'm new to this field & never used any type of photoresists before. I'm trying to develop the 100 um thick metallic (nickel) structure using SU-8 2150 & electroforming process. I already developed the process flow for the fabrication process (for my reference), but since I don't have any experience I'm unaware of the problems.
I heard that removing the SU-8 from the substrate can be very challenging. According to the data sheet of omnicoat, it helps to adhere as well as remove SU-8.
What is the best method to remove SU-8, chemical removal or plasma ashing (what are the conditions used for ashing)? what is the use of Omnicoat then? what are the other problems which may arise? please attach some helpful links in your answers too.
Thank You!
Hi Tanmay, In your situation, plating thick metal layers, the use of Omnicoat is suggested for easier SU8 removal. During the SU8 lithography proces the omnicoat can be removed by plasma ashing (300mT, 100W, 1 min) prior to metal plating. After the metal plating, the Omnicoat layer can be dissolved (in developer) as a sacrificial layer to lift off the SU8.
If you don't have any sacrificial layer below SU8 (like omnicoat) it will be very difficult to remove or strip SU8, even more with thick layers. However ashing at 700°C will help (but your metal layer may suffer) or baking overnight in Sulfuric acid followed by H2O2 can remove SU8.
Dear Mr. Wijnperle as per your answer we have to perform the ashing of omnicoat layer prior to electroplating, but after performing this process & dipping such wafer in bath will delaminate the SU8 (since omnicoat is ashed) in the bath itself or it won't happen unless & until I'm putting it in the omnicoat developer after electroplating?
Dear Tanmay, The (short) ashing of Omnicoat prior to electroplating is required to remove the Omnicoat at the location where you want to electroplate. The Omnicoat which is under the SU8 layer will not be etched in this way and therefore the SU8 will not delaminate during plating. Please let me know whether you succeed!
Thanks to both you for your precious guidance. I will inform you both about the results very soon.
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