Hi everyone
So last Sunday, Ferenc and I brainstormed on how to achieve smaller feature
sizes with a UV wave length, which limits us to 400nm or so.
We discussed splitting a lower feature size layout into multiple masks
and then doing overlapping exposure steps.
Ferenc pointed out, that we might run into an offset issue.
I've been thinking about this for a while and the solution came to me on the 
toilet just now, and it's actually surprisingly simple.
Since we're using a DMD and not physical masks, we can do the multiple 
exposure steps all at once, without any stepping in between.

while(!eow()) { // end of wafer
expose_mask(1);
expose_mask(2);
step_to_next();
}