Extending Optical Lithography Limits: Demonstration by Device Fabrication and Circuit Performance.

To demonstrate the effectiveness of alternating aperture phase shift lithography and 193nm wavelength lithography for integrated circuit technology, two demonstration devices were designed and processed. In one case, a 2 million transistor integrated circuit was processed with phase shifting and 248nm wavelength lithography. Gate lengths were reduced from 240 to 120nm, resulting in a 100MHz circuit speed at 1.0 volt operation, a threefold improvement. In the second case an 80nm floating gate memory device was fabricated with phase shifting, 193nm wavelength lithography, and anti-reflection control. The lithographic results were confirmed by careful measurements throughout the process sequences and finally by the performance of the devices themselves.