ANALYSIS OF SUBWAVELENGTH SIZED OPC FEATURES

Rigorous 3-D electromagnetic analysis is used to examine the actual ne ar field characteristics and assess the resulting effects on imaging o f light passing through serifs and hammer head line-ends in optical pr oximity correction (OPC) of photomasks. The simulation is carried out using the finite-difference time-domain simulator TEMPEST using up to 5 million nodes and 150 M of memory. OPC features which are contiguous and share sides with open features transmit very effectively, whereas OPC features which are isolated by chrome stringers or are cut-off by nearly touching chrome corners are much less effective and require ri gorous electromagnetic analysis.