Yung-Tin Chen

Optimal segmentation of polygon edges

In optical proximity correction, edges of polygons are segmented, and segments are independently moved to meet line-width or edge placement goals. The purpose of segmenting edges is to increase the degrees of freedom in proximity correction. Segmentation is usually performed according to predetermined, geometrical rules. Heuristic, model-based segmentation algorithms have been presented in the literature. We show that there is an optimal and unique way of segmenting polygon edges.

RET for the wiring layer of a 3D memory

A typical wiring layer of SanDisk 3-dimensional memory device includes a dense array of lines. Every other line terminates in an enlarged contact pad at the edge of the array. The pitch of the pads is twice the pitch of the dense array. When process conditions are optimized for the dense array, the gap between the pads becomes a weak point. The gap has a smaller depth of focus. As defocus increases, the space between the pads diminishes and bridges. We present a method of significantly increasing the depth of focus of the pads at the end of the dense array. By placing sub-resolution cutouts in the pads, we equalize the dominant pitch of the pads and the dense array.