Micro-optics: Key enabling technology for photolithography

Photolithography is the engine that empowered microelectronics and semiconductor industry for more than 50 years. Photolithography is the enabling process behind the powerful concept of "shrinkage ", also referred to as "die shrink ", the ability to reduce the minimum feature size of transistors, electronic wires and other components of a microchip from some 50 microns in the early 1960s to some tens of nanometers today. Die shrink allows manufacturing more chips on a wafer, reducing manufacturing costs, minimizing the power consumption and improving the performance in terms of speed, storage capacity and customer convenience. Diffractive and refractive micro-optical elements play a decisive role in modern photolithography systems, e.g. for laser line width narrowing, laser beam shaping (customized illumination), as phase-shift masks (PSM), for optical proximity correction (OPC), and for diffraction-based overlay (DBO). The contribution of micro-optics in photolithography enhancement will be discussed in detail.