Steven,

It sounds like you're referring to the die size limitations of a
stepper. If you're doing microfluidics, odds are you won't be using a
stepper.  You'll just be using a standard contact aligner, which will
expose the entire wafer area at once, instead of the cm scale area a
stepper would do.

If this is the case, you can make multiple chips on a single mask,
and when you expose them with your contact aligner, they'll all be
exposed at once.

- Kevin Paul Nichols
MESA+ Institute for Nanotechnology
Mesoscale Chemical Systems
Meander 151
University of Twente
Postbus 217
7500 AE Enschede
The Netherlands

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On Jul 6, 2007, at 5:38 AM, Steven Yang wrote:

> New to the MEMS field and currently doing MEMS mask design for a
> microfluidic system. I got 3 type system patterns, each has the area
> around 0.5 x 1.5 cm, 1.5 x 1.5 cm, and  1x1.5cm. But i need to vary
> the flow channel size and sub-patterns in each type system pattern for
> the investigation. Therefore, how to use as few as possible mask to
> achieve this?
>
> I was thinking that only one mask can get it done (as my patterns are
> all flow field and flow channel with same depth). However, I heard
> there is a die size limitation in lithography of IC, which means one
> mask can only cover wafer with area around few square meters. In my
> case, seems I need a lot of masks if I need to achieve all pattern on
> one wafer with different sub-pattern from each other . Is this true?
> or there is any other different design rule for MEMS, cos MEMS size
> normally very big comparing to IC and sometime even single system will
> beyond few squaer cm.