Voronoi Diagram of a Polygon in chessboard Metric and Maskless lithographic Applications

Lithography using photomasks has been the major workhorse in printed circuit boards, semiconductors, and flat panel display device manufacturing. However, the cost of photomask is so high that it often becomes the bottleneck, especially when the production volume is low. Recently, maskless lithography technology is gaining more attention, and hence, the computation of efficient lithography path becomes of greater importance than ever in order to obtain high throughput of lithography process. The target machine in mind has a numerically controlled XY table on which a substrate is located and a variable size (square-shape) aperture in front of the light source. In this paper, we present an approach to direct lithography path generation using Voronoi diagram and medial axis transform in chessboard metric. The properties and construction method of Voronoi diagram of a polygonal object in chessboard metric is examined. Then, lithography path generation scheme is explained. The proposed idea can also be applied to the fabrication of photomask itself and the rapid prototyping of a 3D model via layered lithography.