Hi,

I've had a similar effect- it appears as rings which vary in density and
width. The main cause does seem to be heat build up in the sample- I've
found that several shorter etches reduce the problem, but need to find a
lower power recipe (or to increase my sample cooling).

Regards,
Daniel

-----Original Message-----
From: babitha bommalakunta [mailto:[email protected]]
Subject: [mems-talk] si etch help

I am trying to work out Si etch process with CF4 and O2 combination in pecvd
system.My sample appears white after etching . Any idea due to what this
happens?