Hi,

What is the TMAH concentration and temperature ?

I had the same "problem" you described. This could be due to native oxide on
the silicon wafers.

Try to dip wafers for about 1 min in BHF.  It should solve. For me it worked.

Best regards,
Andrea

-----Messaggio originale-----
Da: mems-talk-bounces+mazzolari=fe.infn.it@memsnet.org
[mailto:mems-talk-bounces+mazzolari=fe.infn.it@memsnet.org] Per conto di ???
Inviato: Wednesday, July 06, 2011 11:31 AM
A: mems-talk@memsnet.org
Oggetto: [mems-talk] TMAH doesn't attack some of (100) silicon wafers

Hi, all,

While etching  (100) silicon wafers,  most of wafers were etched normally.
But few of (100) silicon wafers of the same batch were not etched at the
initial time. It seems that the initial reaction just didn't take place.

Has anyone had this experience?

Thanks!