Ionic Surfactants from Dow

Mary Tang mtang at
Wed Sep 23 15:35:44 PDT 2009

Hi Senyo --

A couple of things...

First, could you please briefly outline your procedures?  Basically, I'm 
interested in approximate concentrations, volumes, and whether or not 
heating is involved.  As I'd expect the surfactant is very dilute, it 
should be OK to aspirate the acids.

Second, the surfactants should be OK, but we'd appreciate the MSDS for 
these so we can have them on file.  Dow should provide them.  If not, 
then it would really help if you could provide MSDS for the components 

Lastly, have you tried a "descum" shortly before wet etching?  This is 
typically done in industry prior to wet HF etch to improve wetting.  
However, there's a time limit (of a few hours?) because the resist 
surface has a tendency to go back to being hydrophobic after a while.


Senyo Dogbe wrote:
> Mary,
> We need to wet etch patterned wafers on the WBGAAS in  i)  dilute 
> sulfuric acid  and H2O2    ii)  dilute Ammonium Hydroxide and H2O2.
> We have had problems with wetting / surface tension of the patterned 
> wafers and Dow Chemical sent us 2 types of surfactants to try to see 
> if it will improve the wettability of the wafers during etch. I have 
> attached the information about the surfactants to this email for your 
> approval. The resist used in the patterning is the standard 3612  1um 
> thick resist.
> Thanks
> Senyo

Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
mtang at

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