SCALPEL: projection electron beam lithography

Even though virtually all integrated circuits over the past 30 years have been made using optical lithography, the limits of its usefulness are on the horizon. From the point of view of the physics of the image formation process, it is difficult to imagine practical processes operating at feature sizes at or near half the wavelength of the exposure system. The exposure wavelength trend has been to tend to ever smaller ultraviolet wavelengths but at a pace slower than the feature size trend for integrated circuits. Therefore, both the imaging mechanisms and industry timing indicate that a new disruptive lithography technology will be needed sometime after about 2003. We have developed SCALPEL electron beam lithography to the point where the basic functionality has been shown. Our efforts over the next few years will be to develop the exposure tool, mask and resist technology to the point of commercial introduction consistent with that timing. Ultimately, relative costs of lithography alternatives will determine the successor to current optical technology. The projections are that SCALPEL will operate at a significant cost advantage to sub-wavelength optical technology and other contenders for next generation lithography. Therefore, we feel that SCALPEL is likely to be the industry choice for 100 nm era circuits and beyond