Hello,

The cracks are due to residual stress in the SU-8. You can reduce this by
reducing your exposure time, and ramping the temperature during baking. Use
a hot plate as opposed to an oven. The thicker the layer, the more
susceptible it is to the factors that introduce residual stress.

Michael


>From: Amani Salim 
>Reply-To: General MEMS discussion 
>To: [email protected]
>Subject: [mems-talk] Su-8 craking problem
>Date: Tue, 13 Jul 2004 10:39:04 CDT
>
>Dear colleagues,
>
>Any suggestions for avoiding cracking in Su8?
>am using the 2100 Su8, and am making 100 microns features and follow
>exactly the recipe suggested by microchem, seems like theres still small
>cracks at the border of my 10 microns structures,
>
>any suggestions are very helpful,
>
>regards,
>
>
>
>Amani Salim
>******************************************
>Research Assistant
>Department of Electrical and Computer Eng.
>U of Minnesota,T.C.
>UMBM Lab
>Office phone: 612 626-0590
>Lab phone: 612-626-7188
>
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