Hole Pattern Fabrication using Halftone Phase-Shifting Masks in KrF Lithography
- 1 December 1993
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 32 (12S)
- https://doi.org/10.1143/jjap.32.5880
Abstract
A new concept for enhancing the depth of focus of fine hole patterns is proposed. The concept is based on modulating the complex amplitude of the hole pattern image. It is shown that shifting the origin of the complex amplitude plane enhances the depth of focus. Simulations show that the resolution limit improves to 0.5 λ/NA with the depth of focus of ±1.0 λ/N A 2. It is also shown that halftone phase-shifting masks can be used to shift the origin. The optimum intensity transmittance of the halftone region for maximizing depth of focus is 17.3% for a 0.6 λ/NA hole pattern. Using the optimized halftone phase-shifting mask, a quarter-micron hole pattern can be fabricated with the large depth of focus of 1.4 µm in KrF lithography. Proximity effects for holes arrayed in a row are also discussed.Keywords
This publication has 5 references indexed in Scilit:
- Characteristics of a Monodisperse PHS-Based Positive Resist (MDPR) in KrF Excimer Laser LithographyJapanese Journal of Applied Physics, 1992
- Imaging Characteristics of Multi-Phase-Shifting and Halftone Phase-Shifting MasksJapanese Journal of Applied Physics, 1991
- Spatial filtering for depth of focus and resolution enhancement in optical lithographyJournal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1991
- Phase-shifting photolithography applicable to real IC patternsPublished by SPIE-Intl Soc Optical Eng ,1991
- 0.3-micron Optical Lithography Using A Phase-Shifting MaskPublished by SPIE-Intl Soc Optical Eng ,1989