MSSQ Spin-on Oxide into Lam ETcher

Jim McVittie mcvittie at cis.Stanford.EDU
Tue Mar 1 08:37:45 PST 2005

I am working with Rohit Shenoy to see how well poly-Methylsilsesquioxane
(MSSQ) holds up in the Lam etch for Si etching. The MSSQ to used is a
semiconductor grade spin-on low-k material. It will applied to SNF wafers
at the IBM Almaden cleanroom.  MSSQ is a C-containing variant of SiO2. My
interest is to see if it can be used as a transfer layer under e-beam
resist since it should have a much higher selectivity than PMMA or Zap.  
For his need Rohit would like to follow the Lam step with the std post
etch 50:1 HF dip in wbnonmetal to remove the deposition from the poly etch
step. This step could be done in the general wet bench if there is a
concern about putting MSSQ in the HF tank.

I do not see any problem putting semiconductor clean MSSQ into the Lam. 
I also do not see a problem in putting it into the HF tank in wbnonmetal. 


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