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Proceedings Paper

Simulation study of process control by multistructure CD measurement
Author(s): Wenzhan Zhou; Luke Kok Chin Ng; Carol Yap
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Paper Abstract

As critical-dimension shrink below 0.18 μm, 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 process control. So Advanced Process Control (APC) is going to be a must in the future deep sub-micron lithography, especially 0.18 μm and below. Successful implementation of APC into photolithography depends on how accurate we can determine exposure and defocus from in-line production wafer. Traditionally, in-line process control is based on single structure CD measurement, normally of the smallest dimension as per design. However single import is not enough to predict exposure and focus drift simultaneously. So a lot of studies were done on how to extract exposure and defocus information from in-line CD measurements. And one of these methods is to distinguish focus from energy by monitoring multi-structure CD (CDs of iso/dense, line/pillar and space/hole etc) on normal production wafer. In this paper, we will give a description of this concept. And from that we can see the advantages and drawbacks of this method. Photolithography Simulations (on Prolith) will be carried out to understand the problems we are facing to implement this method into tool matching and inline process control. Finally, we will also propose a new approach to overcome the drawbacks of this method.

Paper Details

Date Published: 2 June 2003
PDF: 12 pages
Proc. SPIE 5038, Metrology, Inspection, and Process Control for Microlithography XVII, (2 June 2003); doi: 10.1117/12.482669
Show Author Affiliations
Wenzhan Zhou, Chartered Semiconductor Manufacturing Ltd. (Singapore)
Luke Kok Chin Ng, Chartered Semiconductor Manufacturing Ltd. (Singapore)
Carol Yap, Chartered Semiconductor Manufacturing Ltd. (Singapore)

Published in SPIE Proceedings Vol. 5038:
Metrology, Inspection, and Process Control for Microlithography XVII
Daniel J. Herr, Editor(s)

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