Hello:

My glass plate is about 66mmX34mm with microchannel pattern. I either
punch holes on glass or PDMS, then seal glass channel on PDMS by O2
plasma, but I always have trouble on bonding. Somewhere on chip sealing
is very good, you have to use blade to remove PDMS, but still PDMS
residual on glass surface, somewhere on chip you can peel PDMS by your
hand. Usually sealing around chip edge isn't good.



I think the problem is two aspects one is glass plate and PDMS clean,
other is O2 plasma process. I tried a lot of parameter on small piece
glass and PDMS bonding (the area is about 1/3 of my real chip). Their
bonding is very good based on following parameter, but when I used the
same condition to bond my real chip, I always got above trouble.



For glass clean I used piranha, before bonding either rinsed by ethanol
then N2 blow dry or adhesion tape clean. For PDMS clean I used the same
cleanliness process as glass plate except piranha. Our RIE system is old
small one. Plasma Oxidation used either filtered air or O2 @ 26 mtorr
pressure, 200W power, 40 sec.



I can't explain my difficulty. If you have experience on this field,
please give me a hand. Thank you very much!