Hi
The thermal expansion coefficient of silicon nitride is very much
different, so it depends what kind of buffer you are using underneath it.
if its on silicon than your silicon nitride has all the possibility of
getting cracked in your heat treatment of ceramics.
Regds
Ravi Shankar
Semiconductor Complex Ltd
India

On Fri, 10 May 2002, Haigh, Richard wrote:

> I am currently trying to etch a Si wafer with hot KOH. There is a Si3N4
> mask (1 um) on the back face wafer. There is a ceramic film on the other
> face, this film requires several high temperature treatments up to 750 C
> (drying and sintering), before the etching can be started. I do not
> believe that these thermal treatments damage the nitride. However
> continued removal and replacement of the nitride mask onto a hotplate
> might result in tiny scratches in the nitride and lead to pinholes in
> the etched sample.
>
> After etching of the back face for >12 hours, there are large pinholes
> (300 um wide by 600 um deep) in my samples. How can I protect the
> nitride from scratching / damage?
>
>
>
> Richard Haigh
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