rookie questions

Michael S. Bartsch mbartsch at
Thu May 6 00:53:13 PDT 2004

Hello Ignacio,

I can't speak to the use of the P5000, but my understanding is that the
STS requires a photoresist mask in order to achieve its high aspect ratio
etches.  Basically your PR mask is what provides the etcher with the
polymer components it needs to passivate the etched side-walls as the
machine cycles through etch and passivation steps.  With an oxide mask
only and no source of polymer, I don't believe you can get the nice,
vertical side-walls you probably want from the etch.

Good luck,

> Dear STS users,
> I am in the process of optimizing a process flow that involves the use of 
> the STS machine here in the lab. I am considering using oxide as a mask, 
> and I wanted to check that I am thinking about the process right. I am 
> planning to use tylanbpsg to put oxide on a Al-coated double-polished 
> wafer(just one side), then I planned to pattern the oxide (and the Al 
> layer) with the same mask using the P5000, finally STSetching trenches and 
> release windows on the front and back of my wafer, respectively. The 
> questions I have are:
> * Is the P5000 plasma etcher the right tool to pattern the oxide?
> * Are oxide masks better in any sense than PR masks in an STS etch?
> Thanks,
> Ignacio
> -- 
> Ignacio A. Zuleta
> Chemistry Department
> Stanford University
> Office: (650)723-4332
> Cellphone: (650)799-9225
> Fax: (650)725-0259

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