Determination of DICD best focus by top-down CD-SEM

Wenzhan Zhou; Hui Kow Lim; Teng Hwee Ng

doi:10.1117/12.473451

16 July 2002 Determination of DICD best focus by top-down CD-SEM

Wenzhan Zhou, Hui Kow Lim, Teng Hwee Ng

Proceedings Volume 4689, Metrology, Inspection, and Process Control for Microlithography XVI; (2002) https://doi.org/10.1117/12.473451
Event: SPIE's 27th Annual International Symposium on Microlithography, 2002, Santa Clara, California, United States

Abstract

As critical-dimension shrink below 0.18 micrometers , the SPC (Statistical Process Control) based CD (Critical Dimension) control in lithography process becomes more difficult. Increasing requirements of a shrinking process window have called on the need for more accurate decision of process window center. However in practical fabrication, we found that top-down CD-SEM showed its limitations in process window center determination, especially for the best focus. For instance, in some extreme focus situation, resist pattern will show a severe undercutting profile which will affect the DICD reading by top-down CD-SEM with fixed measurement algorithm. This kind of DICD measurement error will finally affect the process window center determination (especially best focus) and in-line DICD monitoring, which will lead to the cost of scrap and loss of time for trouble-shooting. In this paper, we will present a detailed study of DICD best focus determination in case of top-down DICD by experiment and simulation. Further a possible solution to this problem will be described in the latter part of this paper.

Citation Download Citation

Wenzhan Zhou, Hui Kow Lim, and Teng Hwee Ng "Determination of DICD best focus by top-down CD-SEM", Proc. SPIE 4689, Metrology, Inspection, and Process Control for Microlithography XVI, (16 July 2002); https://doi.org/10.1117/12.473451

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