Andrea,

Some years ago there was a paper describing a process known as
silylation, where exposed positive photoresist is modified by a
silicon-containing compound, such as HMDS, at elevated temperature and
pressure.  The acid formed by the PR exposure reacts with the Si
forming a Si-rich surface that is resistant to oxygen plasma etching.
The silylated pattern can therefore be "developed" using an oxygen dry
etch, leaving behind a negative image of the original exposure - in
other words, the initially exposed pattern remains on the wafer or
substrate instead of being developed away as normal positive resist.
I believe it is still used but it was never popular due to the
complexity of the process.  Some equipment makers still support the
process (Yield Engineering comes to mind).  You can google silylation
+photoresist and see some patents and articles.  I am not sure if the
service is provided commercially.

Brad Cantos
brad.cantos@holage.com
http://holage.com


On Jul 13, 2009, at 2:35 PM, Andrea Mazzolari wrote:

> Hi all,
>
> is there anyone who can provide photolitography using dry
> development of
> the photoresist ?
>
> Best regards,
> Andrea