NEW DIRECTIONS IN THE DESIGN OF LITHOGRAPHIC RESIST MATERIALS - A CASE-STUDY

In the past decade, major advances in fabricating very large scale integrated (VLSI) electronic devices have placed increasing demands on microlithography, the technology used to generate today's integrated circuits. In 1976, state-of-the-art devices contained several thousand transistors with minimum features of 5-6 mu m. Today, they have several million transistors and minimum features of less than 0.7 mu m. Within the next 10-15 years, a new form of lithography will be required that routinely produces features of less than 0.25 mu m. Short-wavelength (deep-UV) photolithography and scanning electron-beam, X-ray, and scanning ion-beam lithography are the possible alternatives to conventional photolithography. However, each needs new resists and processes. When deep-UV photolithography is implemented, it will represent the first widespread use in manufacture of a lithographic technology that requires an entirely new resist technology. We describe the processes involved in the development of a resist system for this lithographic technique.