Paper
2 June 2003 New method to reduce alignment error by optical system
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Abstract
Advanced stepper or scanner needs extremely high accuracy alignment system. This alignment accuracy is mainly affected by the errors caused by mark deformations and by optical system. To improve the alignment accuracy of our wafer alignment system called 'FIA' we have developed a method called the 'FFO'. Our studies have already shown that FFO has the effect of reducing the errors caused by mark deformations. To examine the errors caused by optical system, new approaches are adopted. In the new approaches a simulation method and a suitable experimental are used. The simulation results by the new method, Spatial Frequency Analysis of Image, show the relation between defocus and the errors caused by optical system and the superiority of FFO. Suitable experimental system brings us the same results as the simulation method. As a result, FFO also has a positive effect on the errors caused by optical system. FIA with FFO is much more accurate alignment sensor for ULSI production.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tadashi Nagayama, Shinichi Nakajima, Ayako Sugaya, Yuho Kanaya, and Ayako Sukegawa "New method to reduce alignment error by optical system", Proc. SPIE 5038, Metrology, Inspection, and Process Control for Microlithography XVII, (2 June 2003); https://doi.org/10.1117/12.483513
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Cited by 7 scholarly publications.
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KEYWORDS
Optical alignment

Semiconducting wafers

Monochromatic aberrations

Neodymium

Microscopes

Chemical mechanical planarization

Phase shifts

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