Hi Meifang,

You could try mechanical interlocking to physically restrain your SU-8
structures on the Si substrate. What is the typical structure
footprint?

Journal of Micromechanics and Microengineering, Volume 15, Issue 11,
pp. 2074-2082 (2005).

Regards,

Michael


---------- Forwarded message ----------
From: "Meifang Lai" 
To: "'General MEMS discussion'" 
Date: Wed, 9 Jul 2008 17:50:37 +0800
Subject: [mems-talk] adhesion problem for SU-8 on Si when hot-embossing
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.

Cheers,

Meifang