Application of critical shape analyses to two-dimensional patterns

2D optical proximity correction is a requirement for feature patterning at 0.18 micrometers and below lithography process nodes. These corrections to semiconductor designs are intended to address the non-linearities of pattern transfer between mask making, lithography, and etch. Traditionally, IC patterns from design through etch have been characterized using critical dimension (CD) measurements. Semiconductor devices, however, are not simply made up of one-dimensional structures such as long lines and spaces. In many cases CD measurements alone are insufficient metrics of imaging performance. The fidelity of two-dimensional printed features is as important as the CD. This paper will examine the pattern fidelity of arbitrarily shaped two-dimensional patterns. Metrics such as pattern area, corner rounding, line end shorting, and the critical shape difference will be used as characterize the process. Both experimental and simulated data will be used to explore the importance of two-dimensional critical shape verses two-dimensional area on feature transfer.