Have you run into the Kooi effect?

Roger Brennan
Applications Director
Solecon Labs
770 Trademark Drive
Reno, NV 89521-5926

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Kuijpers, Peter
Sent: Monday, December 21, 2009 12:18 AM
To: [email protected]
Subject: [mems-talk] Oxidation of KOH etched Si wafers


Good morning,

During KOH etch a patterned low stress SiN layer was used as etching mask.
Afterwards this SiN layer was etched for about 4hr in H3PO4 at 140°C. As
next a wet-oxidation process took place on the Si, but we did get a very
non-uniform and very thin SiO2 layer (target was 100nm, measured thickness
16nm?). Our theory is that there is still a (very) thin layer of SiN
present. Could this be the cause and is there another way to selectively
remove this low stress SiN layer in a well controlled way (HF and RIE are
not possible).

Looking forward to your answers.

Best regards,
Peter Kuijpers
MiPlaza Technology Laboratories
Philips Research Europe
High Tech Campus 04
Postbox HTC-4-1
5656 AE Eindhoven
The Netherlands
Tel.: +31 402743667
         +31 612507027
Email: [email protected]