If you try  to make a homogenous solution of PVA then make a 5%solution in
DD water. by 200rpm and 70degree of temperature.

On 17/12/06, Mustafa Celik  wrote:
>
> Hi all,
>
> I am trying to pattern a film of   polyvinyl
> alcohol(PVA) on Si wafer.
> Process steps are:
> - Preparation of %4 aqeous PVA solution ( I also have
> problems with this, can't obtain   homogenous
> solution)
> - Spin-coat  of PVA solution @2000  RPM
> - Soft bake for 30min @90 C
> - AZ1823 PR spin-caoting
> - Soft bake for 1 min @90 C
> - Exposure of PR and development
> - Etching of PVA in DI water for 15 sec
> - Drying of substrate and hard-bake for 30 min @140 C
> ( heat treatment makes   PVA  insoluble in water again
> )
> - Removal of PR in Acetone. This step  demages  the
> substrate, surface becomes white and bloats . I tried
> different  hard-bake  times  but nothing changed.
>
> Thank you for your help in advance,
>
>
>
> Mustafa Celik
>
> Uludag University
> Electrical and Electronics Eng. Dep.
> Bursa/Turkey
>
> Mustafa Celik
>
> Uludag University
> Electrical and Electronics Eng. Dep.
> Bursa/Turkey
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                     Mohendra Roy.