[mems-talk] adhesion problem for SU-8 on Si when hot-embossing

[Fabrice Monti]

Hi,

I had a similar problem with the SU8. the problem 
was the exposure time was too short. after that, 
i studied the impact on the exposure time. If 
your structure are under-exposed the bonding 
between SI and SU8 is really bad. If your 
structure are over exposed, the larger increase.
  in my case, i measured the light power with a 
powermeter but without the quartz plate (support 
of my mask) and the mask i used. the difference is over 40% !!!

best regards,

fabrice


Le 11:50 09/07/2008,Meifang Lai écrit:
>Hi all,
>
>I am developing a mold for hot-embossing by 
>using SU-8 2050 on Si wafer. At present, I can 
>get beautiful structures on Si after the 
>photolithography process  (including hard bake 
>at 150 ⁰C for 30 min). However, when I was 
>trying to transfer the structure to PMMA (1 inch 
>square) by hot embossing (pressure is 300 Kg, 
>125 ⁰C for 10min, and the demolding 
>temperature is 90 ⁰C), all the Su-8 structures 
>stayed in PMMA and separated from Si wafer. I 
>have tried the HMDS, but it seems no difference. 
>Does anyone have similar experience? Any suggestion will be appreciated.