Hi Jiang,

your clogging problem is concerned by the low Glass transmission temperature
of unexposed SU8
(Tg=55°C). You should try it with both wafers exposed. You can use a flood
exposure. Then you can raise the bonding temperature up to 100°C without
having any clogging.

best regards

Ulrike Schömbs

-----Ursprüngliche Nachricht-----
Von: Jiang Ziling [mailto:spmtfmpcs@gmail.com]

hi all,

  I tried to make channel by bonding two Glass wafers, one with a 50um
exposed Su-8 layer with channel on it, another with a 50um unexposed
Su-8 layer. According to some research, at 75 degree centigrade the
unexposed Su-8 can reform shape and bond with the exposed layer when
certain pressure is applied. But I tested and found that the 100um
wide channels on the exposed su-8 surface are always clogged by the
soft Su-8 flowing from the unexposed layer during pressing-bonding.
However, if I don't press, there will be no bonding. Does anyone have
experience in solving this clogging problem?