Computational Lithography

Preface

Moore's law and the integrated circuit industry have led the electronics industry to make technological advances that have transformed the society in many ways. Wireless communications, the Internet, and the astonishing new modalities in medical imaging have all been realized by the availability of the computational power inside IC processors. At this pace, if Moore's law continues to hold for the next couple of decades, the computational power of integrated circuits will play a key role in unveiling the secrets of the working mechanisms behind the living brain, it will also be the enabler in the advances of health informatics and of the solutions to other grand challenges singled out by the National Academy of Engineering. Maintaining this pace, however, requires a constant search by the semiconductor industry for new approaches to reduce the size of transistors. At the heart of Moore's law is optical lithography by which ICs are patterned, one layer at a time. By steadily reducing the wavelength of light in optical lithography, the IC industry has kept pace with the Moore's law. In the past two decades, the wavelength used in optical lithography has shrunk down to today's standard of 193 nm. This strategy, however, has become less certain as wavelengths shorter than 193 nm cannot be used without a major overhaul of the lithographic process, since shorter wavelengths are absorbed by the optical elements in lithography. While new lithography methods are under development, ...