IF you can use a different substrate, I have found that the easiest
thing to do is buy test grade photomasks with the chrome and resist
already on them.  We use glass from Nanofilm in Westlake Village CA.  We
use BOE to etch the glass.  It is slow but we only need to etch 10-20
microns.  We do get undercutting of the chrome, we don't even keep the
resist for the glass etch.  Agitation in the BOE and frequent stops for
cleaning in a sulfuric acid hydrogen peroxide solution are an absolute
must for us to get features we consider smooth.  I would be interested
in knowing if you are using a dry etch.


Mark

>>> pb96@cornell.edu 08/06/04 3:13 PM >>>

>When I am doing glass etching, I coated chromium sacrificial layer to
>increase adhesion by sputtering, first. And on this layer, coat
photoresist
>1818, develop PR and etch Cr. Then after glass is exposed, start to
etching
>glass.
>
>
>
>But, when glass is etching, the edge of sacrificial layer is defected.
>Therefore, the side well of channel is very rough, not smooth.
>
>If someone knows the answer how to increase adhesion between glass and
Cr,
>and Cr and photoresist, please let me know.
>
>Thank you.
>
>
>
>Jinkee Lee

What chemistry do you use to etch the glass. My experience is that Soda
lime glass cannot be dry etched cleanly. This has to do with the
chemistry
of the glass. You can use Fused Silica glass which would give you clean
profile. I dry etch fused silica without any metal mask.

Pari.

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