I would explain my pb
My aim is to order mask with less works to do for GDS guys
We have some projects with cells. Cell contains some features. This is my GDS.
To order mask , I need to say , that all my mask is chrome (darkfield) , and do a clear around my cells. This operation isn't easy and waste time.
Is it possible , when GDS is finished ,( with only cells inside ) to do a operation who keep my cells ( without changing polarity) but put chrome in my active area ( mask area)
I'd like too , to have around each cell a addition of 5 microns of clear( to protect some features in cell )
The result will be , chrome on mask with clear area ( 5 microns bigger than cell inside) , and in these area , my cells.
I'm afraid I don't really understand your request.
With a clear field mask you get glass where you have drawn something. If you have a darkfield mask you need to reverse the data. Is you request about inverting the layout for this case?
Usually you do this by drawing a big rectangle around your layout on a separate "boundary" layer and performing a boolean NOT between this layer and the drawn layer. A manual way to do this is to use "Edit/Layer/Boolean Operations". For a scripted solution I'd suggest to use the DRC feature which can produce a new layout from an input layout with the desired features.