Kuijpers

    It is possible that the low stress SiN layer was not entirely removed by
H3PO4 etching. Even with the plasma, we find the low stress SiN is still
difficult to etch. If it is possible, you can try ion beam mill?

Regards!

2009-12-22

xudehui0108

发件人： Kuijpers, Peter
发送时间： 2009-12-21  15:18:05
收件人： mems-talk@memsnet.org
抄送：
主题： [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: p.e.m.kuijpers@philips.com