Lindlein N (2002)
Publication Type: Journal article
Publication year: 2002
Publisher: International Society for Optical Engineering; 1999
Book Volume: 4691
Pages Range: 541
DOI: 10.1117/12.474601
The physical limits of optical lithography are mainly determined by the aperture of the mask projection system and the wavelength of the light. In addition to the wavelength shift to the deep UV the application of special techniques to improve the processing window are required. This has furthered the application of the phase shift mask as a lithography tool. The generation of the exact intensity distribution needed in the plane of the wafer strongly depends on the accuracy of the phase shift introduced by the phase shift mask. However, one difficult issue is the reliable measurement of the phase shift introduced by the phase mask at the working wavelength. This is of course mainly due to the lack of suitable and simple interferometric devices for the deep-UV-region - here 193 nm. We propose the use of a diffractive shearing interferometer as a way out. By combining two Ronchi-phase gratings it is possible to produce shear and phase shifts for the evaluation of the fringe patterns simply by axial and lateral shifts of the phase gratings relative to each other. Since the excimer laser emits spatially partial coherent light only the coherence issue is one of the physical problems dealt with in our experiments. The state of the art of our experiments so far reached will be presented.
APA:
Lindlein, N. (2002). Lateral Shearing Interferometer for Phase Shift Mask Measurement at 193 nm. Proceedings of SPIE, 4691, 541. https://doi.org/10.1117/12.474601
MLA:
Lindlein, Norbert. "Lateral Shearing Interferometer for Phase Shift Mask Measurement at 193 nm." Proceedings of SPIE 4691 (2002): 541.
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