[mems-talk] Photoresist as etch mask! (Nitin Shukla)

[K.P.Nichols at utwente.nl]

I haven't looked into it much, but (regarding the statement below) I'm pretty sure SU-8 will delaminate in any KOH etch of moderate length. I assume KPMR behaves the same, if not worse. 

Anyone looked into this, or found a solution?

- Kevin


-----Original Message-----
From: mems-talk-bounces at memsnet.org on behalf of Frank Yaghmaie
Sent: Tue 10/2/2007 6:48 PM
To: mems-talk at memsnet.org
Subject: [mems-talk] Photoresist as etch mask! (Nitin Shukla)
 
Nearly all positive tone resists patterns are dissolved in TMAH or  
KOH at standard concentrations used for Silicon etch. As such, they  
can not be used as etch mask for Silicon wet etch processes even at  
room temp. They are much more effective when used in wet acid etch  
image transfer steps.

Negative tone resists such as SU8 or KMPR have some advantage over  
positive tone resist for your application, yet for wet  Silicon etch,  
you may want to consider a hard mask, preferably Silicon-Nitride  
( Si3N4) or Silicon-Oxide ( Thermal SiO2) .