Hello all,

At our site we use LPCVD SiN or paryleen as protection for the frontside.


Peter Kuijpers
MiPlaza
Technology Laboratories
High Tech Campus 04
Room: WAGp5-11
5656 AE Eindhoven
The Netherlands
Phone.: (+31 40 27) 43667
mobile:(+31) 06-12507027
fax.: [+31 40 27) 44769
mailto:[email protected]
________________________________________
Van: [email protected] [mems-talk-
[email protected]] namens Temmuz
[[email protected]]
Verzonden: zondag 22 augustus 2010 1:14
Aan: [email protected]
Onderwerp: [mems-talk] KOH resistant paste

Hello,

I am trying to do back side etching to Si based SOI wafer entirely
(500um etch).  As etchant, I am using %30 KOH at 80 degrees for 7-8
hours.  In order to protect the topside, I am using 500nm thick nitride
layer, however, because of the void formations during PECVD SiN
deposition process, KOH etches everything on the topside.  DRIE is not
an option for me.  Finally I decided to paste my sample to glass in
order to etch only the backside.  Does anyone know of a paste, like
silver paste or epoxy, which can resist to extended hours of KOH etching
without getting etched at all?

OR!

Do anyone know of a way which I can protect the topside of my sample
during etching?

P.S.  As I read the archives, I learned that Protek B3 coating or
annealing to high temperatures (800 degrees) can work, however, as some
of the members say, coating is hard to remove and I can not anneal up to
800 or more degrees since my features include Al (it has melting point
of 660 degrees).

Thank you.

Temmuz CEYHAN