A high throughput NGL electron beam direct-write lithography system

Electron beam lithography systems have historically had low throughput. The only practical solution to this limitation is an approach using many beams writing simultaneously. For single-column multi-beam systems, including projection optics (SCALPEL(R) and PREVAIL) and blanked aperture arrays, throughput and resolution are limited by space-charge effects. Multibeam micro-column (one beam per column) systems are limited by the need for low voltage operation, electrical connection density and fabrication complexities. In this paper, we discuss a new multi-beam concept employing multiple columns each with multiple beams to generate a very large total number of parallel writing beams. This overcomes the limitations of space-charge interactions and low voltage operation. We also discuss a rationale leading to the optimum number of columns and beams per column. Using this approach we show how production throughputs greater than or equal to 60 wafers per hour can be achieved at CDs less than or equal to 100 nm, independent of both wafer diameter and die size. The Cost-of-Ownership (CoO) advantages of direct-write (maskless) lithography are significant especially for small-volume semiconductor fabrication, for example ASICs, SOCs and MPUs.