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Overlay and Alignment Control on Non-Developed Wafers by the Interferential Contrast Technique

IP.com Disclosure Number: IPCOM000034530D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bernadou, F: AUTHOR [+4]

Abstract

The problem to be solved is overlay and alignment reading, just after exposure, but without any development of the photoresist. The novel disclosure is that of an application of the optical differential interference contrast technique in semiconductor manufacturing. Interferential contrast allows reading on any layer without photoresist development. The image is very clear and precise and thus allows very fine reading, as good as that provided by a developed wafer. Optical differential interference contrast allows easy microscope inspection for defect detection and film homogeneity. Details so small or refractive index variations that are not visible with any other optical inspection technique appear clearly with a three-dimensional effect.

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Overlay and Alignment Control on Non-Developed Wafers by the Interferential Contrast Technique

The problem to be solved is overlay and alignment reading, just after exposure, but without any development of the photoresist. The novel disclosure is that of an application of the optical differential interference contrast technique in semiconductor manufacturing. Interferential contrast allows reading on any layer without photoresist development. The image is very clear and precise and thus allows very fine reading, as good as that provided by a developed wafer. Optical differential interference contrast allows easy microscope inspection for defect detection and film homogeneity. Details so small or refractive index variations that are not visible with any other optical inspection technique appear clearly with a three-dimensional effect. In microphotolithography manufacturing immediate printed image inspection is then possible just after exposure and does not need development, rinse and dry wait time before test wafer inspection. Therefore, immediate overlay and alignment reading focus inspection is available without development parameters. After ionic implantation, implanted areas are visible even after resist stripping. As a result, an effective implantation check by a non- destructive method is allowed.

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