Paper
25 July 1989 0.3-micron Optical Lithography Using A Phase-Shifting Mask
Tsuneo Terasawa, Norio Hasegawa, Toshiei Kurosaki, Toshihiko Tanaka
Author Affiliations +
Abstract
Improved resolution of an available i-line (365nm) stepper using a phase-shifting mask is discussed. The resolution investigated here is not only for periodic lines but also for isolated spaces and hole patterns. To obtain a narrow bright line for printing a fine isolated space on a wafer, two additional line apertures with widths smaller than the critical dimension of the stepper lens are placed on each side of the main aperture of the mask. The optical phase of the main aperture and those of additional apertures are opposite. The additional apertures play a role in reducing the bright feature size to less than the line spread function of the lens. Similarly, printing a fine hole is accomplished by using a main aperture surrounded by four additional apertures. The intensity distribution on the wafer is calculated by comparing the results obtained with a phase-shifting mask and those obtained with a conventional transmission mask. Patterns are also printed on the wafer using an i-line stepper with a nominal 0.55 μm resolution. A pattern of 0.3-μm lines and spaces, 0.3-μm isolated spaces and 0.4-μm hole patterns are resolved using the phase-shifting mask. This resolution is impossible with a conventional transmission mask. The effects of variations in the optical phase of the additional apertures are also investigated. The intensity calculations and experimental results suggest that it is possible to control the position of the best focal plane by changing the optical phases of the additional apertures.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tsuneo Terasawa, Norio Hasegawa, Toshiei Kurosaki, and Toshihiko Tanaka "0.3-micron Optical Lithography Using A Phase-Shifting Mask", Proc. SPIE 1088, Optical/Laser Microlithography II, (25 July 1989); https://doi.org/10.1117/12.953131
Lens.org Logo
CITATIONS
Cited by 48 scholarly publications and 77 patents.
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Photomasks

Phase shifts

Semiconducting wafers

Wafer-level optics

Phase shifting

Photoresist materials

Optical lithography

Back to Top