Hi,

When I do double coats of SU-8 to 100 or 150 µm I simply perform the same coat
sequence twice.  Thicker double coats may require changes to the first bake
process.  Excessive heat seems to begin crosslinking SU-8 at the wafer but that
shouldn't be the case here.

Best Regards,
Garrett Oakes

EV Group
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-----Original Message-----
From: jiang Liudi [mailto:ldjiang@hotmail.com]
Sent: Thursday, August 07, 2008 12:27 AM
To: General MEMS discussion
Subject: Re: [mems-talk] Su 8 thickness

Hi,
Many thanks for kind suggestions.

I think double coat could be the solution. could you further suggest procedures
of double layers in terms of baking, expose and PEB?According according to the
data sheet, 1700rpm should get almost 140um thickness. is it common for half the
thickness, compared with the sheet?

thanks again.