Model-Based Mask Data Preparation

Sure!

MB-MDP is the simulation-based new approach to mask data preparation.  Instead of the conventional approach that is "rule-based" where the incoming shape to be projected on the mask is "fractured", MB-MDP does mask simulation on every proposed shot to compose a set of shots that create the desired mask image.  In conventional fracturing, a set of rectangles that tesselates the desired mask shape is determined by "cutting" the shape horizontally and vertically.  As a result, the union of the shots is the desired shape, and no shots overlap.  The MB-MDP solution enables three additional degrees of freedom by its nature : 1) shots may overlap; 2) shots may be assigned individual dose; and 3) shots may be of any shape character whatsoever, with the most useful and interesting being a circle.

It is certainly very useful for EUV masks.  Even though EUV masks do not have highly decorated OPC patterns, EUV masks need to be very accurate because mask defects more accurately get reflected on the wafer.  In addition, EUV masks by its reflective nature have more complex mask effects that affect accuracy.  The benefit of MB-MDP for EUV masks is more for enhancing mask fidelity than for savings in mask write times.

Thanks for the explanation, Aki.

It sounds to me like something that could be fairly complex. Does it add a lot of shots to the process? Do you have to have a machine with circular apertures? If so, when would such machines likely be available?