I don't have much personal experience with it, but maybe try solvent
bonding. You coat one (or both) sides to be mated with some solvent to
melt it a bit and get it tacky, then mate, and it bonds. The trick is to
find the right solvent and use an amount and concentration that doesn't
distort your features.

-Joe Grogan

Rashid, Mamun wrote:
> Dear All,
> I am currently working on the polymer based (Polystyrene) micro fluidic
> device. The combined device has two layer top and bottom. Top layer
> contains the micro channel (50uM) and the bottom layer contains the
> micro electrode which is 150nm thick. I am facing problem for the
> bonding. Polystyrene Tg is near 100 degree. I got good result if I
> follow thermal (vacuum) bonding procedure at the bonding temperature 105
> degree with slow ramp of heating and cooling. But the problem is after
> bonding the micro electrode cracks due to expansion of the polymer
> layer.
> I have also tried with the ultra sonic bonging, but have not any good
> result.
> I can have any suggestion regarding the bonding problem please?