Design considerations for an electron-beam pattern generator for the 130-nm generation of masks

The critical dimension (CD) requirements of the SIA roadmap require continued improvements in pattern generation (PG) tool technology. This includes electron-beam (e-beam) delivery, resist and process, writing strategy, and overall system throughput. In this paper, we discuss these interrelated topics and evaluate their impacts on the CD control, linearity, and uniformity performance of PG tools. By means of Monte Carlo simulations and experimental comparisons, we evaluate various parameters of e-beam delivery systems, including beam energy, spot size, writing strategy, and throughput. We also perform a thorough evaluation of mask heating effects due to e-beam exposure. Finally, we perform comparative studies of various resist and process combinations. The totality of our investigations allows us to conclude that a 50 kV raster scan e-beam system, using a high- contrast, high-sensitivity resist, such as SPR 700, with GHOST proximity effect correction (PEC), can meet the CD control, linearity, and uniformity requirements of the 130 nm technology node.