Subject: Re: UVN-30 and GaAs
From: Kai-Mei Camilla Fu <>
Date: Fri, 19 Sep 2003 18:41:45 -0700 (PDT)

There was HMDS on all samples, deposited using the YES oven.  The SNF
process sheet was followed for UVN-30 which includes HMDS.

On Fri, 19 Sep 2003, James Conway wrote:

> Please use HMDS prime on all III-V substrates after complete substrate cleans
> and careful N2 blow off.
> Standard practice everywhere...
> All the best,
> James Conway
> Kai-Mei Camilla Fu wrote:
> > Hello,
> >
> > After a bit of frustration with wandering features, someone finally
> > suggested that I do my process on Si and GaAs at the same time.  I did the
> > SNF process for UVN-30 on raith on Si, GaAs, and GaN this morning and
> > found that the Si sample did not have any adhesion problems.  ON the GaAs
> > sample I was able to find bits of patterns.  On the GaN sample I was able
> > to find a part of the dose array somewhat intact. I varied the doses from
> > 2-20 uC/cm^2 and most features were overexposed.
> >
> > I feel like this would be interesting information for future users of
> > UVN30.  I am not sure if there is a way to get around this adhesion
> > problem with GaAs but the current SNF process does not work for GaAs or
> > GaN.
> >
> > If you have any suggestions please let me know.  Someone suggested I try
> > spinning HMDS on myself.  Since I thought the YES oven was optimized for
> > HMDS I am a bit weary of trying this, but if you have had experience with
> > better adhesion by spinning I will certainly give it a try.
> >
> > Kai-Mei