The Evolution of Materials for the Photolithographic Process

Underlying the rapid growth of the semiconductor field is a significant advancement in the materials utilized in the photolithographic process. In order to produce smaller devices, exposure wavelengths are decreased. Each wavelength reduction has demanded the synthesis of novel materials that are not only transparent at the new wavelength, but also meet all of the requirements of an effective resist polymer. The transition from 248 nm exposures to 193 nm precluded the use of aromatic functional groups, and the recent drop to 157 nm exposure has inspired a large amount of effort toward the development of resist materials containing fluorine. The Semiconductor Industry Association (SIA) roadmap predicts the use of extreme ultra-violet (EUV) radiation as the next move for the industry, but the high cost and high energy associated with this technology may make alternative lithographic technologies seem more practical.