Characteristics for negative and positive tone resists with direct write electron beam and SCALPEL exposure systems

Abstract

High acceleration voltage electron beam exposure is one of the possible candidates for post optical lithography, where tighter resolution and wide process latitude is required. The use of highly accelerated electrons instead of photons prevents optical related problems, such as standing waves, because the interaction mechanisms between the resist and photons and electrons are different. The present work will describe results obtained with a 50 kV direct write e-beam exposure tool and SCALPEL, which operates at 100 kV acceleration voltage on positive and negative chemically amplified resists from Tokyo Ohka Kogyo (TOK). TOK has designed a positive tone resist, EP-004, with 100 nm resolution for line and space patterns. The dose to print on SCALPEL is 6 μC/cm2 and process latitude is about 10%. The TOK negative resist, EN-009, has 100 nm resolution for isolated lines. The dose to print on SCALPEL is 7 μC/cm2 and process latitude is about 15%. These results are the first to meet high throughput requirements for SCALPEL in terms of resist sensitivity and process latitude, which are: dose between 5 and 10 μC/cm2 and process latitude greater than 10%.