Try to use quartz wafer (or fused silica) for either of cover or your substrate
and Pyrex 7740 wafer as the matching one. Try to use the wafer which has good
surface roughness.

  sok

Hyun Chul Jung  wrote:
  Hello guys.

I am having difficult time to bond glass to glass. Bottom substrate has
2um wide and deep microfluidic channels and electrodes (Ti/Au
200/1000A). Top substrate is just plain pyrex 7740.
I have been trying two methods so far.

First one is anodic bonding.
I deposited SiO2 on top substrate using Ebeam evaporator. Tried to bond
using anodic bond. It did not work.

Second method is PDMS to glass bonding.
First of all, I spined coat PDMS liquid on top substrate around 6um
thickness and curing for 30 min at 180C on hotplate. Cool down it for
while. Oxygen plasma treatment on both side of substrate and then place
them together. It did not work either.

If I miss some steps, please correct me. I will really appreciate if you
guys give me any comments or recommendation.
Thanks.