I believe that it is an easy process and i used to do it very easily earlier when i used to leave the PDMS curing at room temp about 24 hours. now i started curing on hotplate at 120 'C for an hour which didn't worked as the PDMS was sticked to the silicon. then i tried 100 'C for an hour which was even more worst.
Need suggestions.
Thanks in advance.
Karthik Mahesh
thanks for you feedback. I always make sure the ratio and i also give enough gap between heating and peeling off.I never tried using IPA before pouring PDMS which will be helpful i guess and could be the possible reason of some remains on wafer which probably helps PDMS to stick hard to the wafer.
PDMS bonds covalently to clean glass/silicon at those temperatures. Think of it as a feature, perhaps some day you will actually want it to happen.
If you want to peel it off, cure it at lower temperature, like 60 °C or below.
Otherwise treat the wafer with a fluorosilane, it is very easy and you will be able to reuse it lots of times!
Treat the silicon wafer with vapors of trichloro perfluorooctyl silane. That's the trick. In my own experience, never pour the PDMS mixture just after cleaning the wafer with plasma (never).
Hii Please follow these steps before pouring PDMS:
(1) clean the wafer in acetone, IPA and DI.
(2) put in silane for 30 minutes.
(3) then put in hexane for 10 minutes.
(4) then put in 1-Octanol for 10 minutes
Wash with acetone and then pour PDMS. Each time you will get good results.
1. Si wafer need to be treated with an anti-sticking agent (tridecafluoro-1, 1, 2, 2-tetrahydrooctyl)-trichlorosilane (Gelest Inc.) by exposure in a desiccator under vacuum for 30 mins.
2. PDMS solution is prepared using SYLGARD 184 Elastomer Kit (Dow Corning Corporation, Midland, MI) with a base-to-curing agent ratio of 10:1 (wt/wt).
3. The pre-polymer solution is thoroughly mixed and degassed under vacuum for 30 mins to eliminate all air bubbles.
4. Then, the mixture is poured over the silicon substrates in a Petri dish, cured at 70 °C for 2 hours.
1. If the silicon wafer is coated with Trichloro(1H,1H,2H,2H-perfluorooctyl)silane in vacuum desiccator for 10 minutes and then if you cure PDMS at whatever the temperature, it will get peeled off easily.
2. Additionally, if the silicone wafter is oxidised (700nm-1um thick), and even without any coating, there shouldn't be any problem in peeling off.
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