OPC convergence improvement by matrix OPC solver on high MEEF contact layer

The use of dense pitch and single exposure process make 28nm contact layer known as one high MEEF (Mask Error Enhancement Factor) and low contrast layer, which also causes slow and poor OPC convergence. Traditional OPC method only considers edge placement error itself to determine its fragment's movement at each iteration. It becomes unadaptable for dense and high MEEF layout for 28nm node and beyond. Instead, matrix OPC solver is a more advanced OPC algorithm that takes neighboring segments' movement into account at each iteration. For each fragment on the chip, the impact of every neighbor fragment's movement is computed. In this paper, matrix OPC solver benefit is investigated and analyzed based on some typical Contact layouts with high MEEF. The result shows better OPC convergence can be obtained even with less OPC iterations.