A Multi-objective Floorplanner for Shuttle Mask Optimization

Shrinkage of VLSI feature size and use of advanced Reticle Enhancement Technologies (RET) in manufacturing such as OPC and PSM have dramatically pushed up cost of mask. For example of a 130nm or 90nm mask set, the mask cost can easily reach one or two million US dollars. Shuttle mask is an effective method to share the mask cost by putting different chips on the same mask. Shuttle mask floorplanning is a key step to pack these chips according to certain objectives and constraints related to cost, yield, and manufacturability. In this paper, we present a simulated annealing based floorplanner to solve the shuttle mask floorplanning problem with multiple optimization objectives and constraints. We will consider area minimization, density optimization (for manufacturability enhancement with CMP), wafer utilization maximization, die-to-die inspection constraint, die orientation constraint and their combinations. A nice property of our floorplanner is that it can be easily adapted to different cost models of mask and wafer manufacturing. Experiments on industry data show promising results.