Optical Lithography

Optical lithography is the most basic technology in nanofabrication. Pushed by integrated circuit (IC) manufacturing in the last 60 years, this technology has been developed so advanced that it is now capable of sub-10 nm patterning resolution. Starting from the most basic equation of diffractive optics (Eq. 2.3), this chapter describes the principles of optical lithography in very accessible manner, helped visually by many graphs of computer-simulated diffracted light intensity. The advances in optical lithography, particularly the new developments since the second edition of this book, are introduced along the aspects of optical wavelength, numerical aperture of imaging systems, and k1 factor as presented in Eq. 2.3. While the updated progresses closely related to the very latest IC manufacturing are amply described, other optical lithography techniques such as near-field, Talbot, interferometric, maskless, and two-photon polymerization are also introduced, which are not aimed at high-throughput patterning but mostly used by scientific community.