ABSTRACT

Optical lithography has served as the dominant patterning technology in the semiconductor industry since the integrated circuit was invented nearly 50 years ago. This chapter outlines some of the basic principles of optical lithography and attempts to describe some of the non-traditional enhancement techniques that are now becoming important for mainstream manufacturing use. An often asked question is how long optical lithography can continue to be the mainstream patterning technology for the semiconductor industry. Practical lithography is based on replicating the pattern defined on a photomask into resist-covered wafers. Novel optical approaches have been proposed that could push the capability of optical lithography well beyond simple scaling of the tools that in use today. Even without radical changes in tool design it appears that optical lithography will prevail for at least another 5–10 years, supporting semiconductor technology beyond 50 nm line and space patterning.