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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Device-correlated metrology for overlay measurements
Author(s): Charlie Chen; George K. C. Huang; Yuan Chi Pai; Jimmy C. H. Wu; Yu Wei Cheng; Simon C. C. Hsu; Chun Chi Yu; Nuriel Amir; DongSub Choi; Tal Itzkovich; Inna Tarshish-Shapir; David C. Tien; Eros Huang; Kelly T. L. Kuo; Takeshi Kato; Osamu Inoue; Hiroki Kawada; Yutaka Okagawa; Luis Huang; Matthew Hsu; Amei Su

Paper Abstract

One of the main issues with accuracy is the bias between the overlay (OVL) target and actual device OVL. In this study, we introduce the concept of device-correlated metrology (DCM), which is a systematic approach to quantify and overcome the bias between target-based OVL results and device OVL values. In order to systematically quantify the bias components between target and device, we introduce a new hybrid target integrating an optical OVL target with a device mimicking critical dimension scanning electron microscope (CD-SEM) target. The hybrid OVL target is designed to accurately represent the process influence on the actual device. In the general case, the CD-SEM can measure the bias between the target and device on the same layer after etch inspection (AEI) for all layers, the OVL between layers at AEI for most cases and after develop inspection for limited cases such as double-patterning layers. The results have shown that for the innovative process compatible hybrid targets the bias between the target and device is small, within the order of CD-SEM noise. Direct OVL measurements by CD-SEM show excellent correlation between CD-SEM and optical OVL measurements at certain conditions. This correlation helps verify the accuracy of the optical measurement results and is applicable for the imaging base OVL method using several target types advance imaging metrology, advance imaging metrology in die OVL, and the scatterometrybase OVL method. Future plans include broadening the hybrid target design to better mimic each layer process conditions such as pattern density. Additionally, for memory devices we are developing hybrid targets which enable other methods of accuracy verification.

Paper Details

Date Published: 6 October 2014
PDF: 6 pages
J. Micro/Nanolith. MEMS MOEMS 13(4) 041404 doi: 10.1117/1.JMM.13.4.041404
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 13, Issue 4
Show Author Affiliations
Charlie Chen, United Microelectronics Corp. (Taiwan)
George K. C. Huang, United Microelectronics Corp. (Taiwan)
Yuan Chi Pai, United Microelectronics Corp. (Taiwan)
Jimmy C. H. Wu, United Microelectronics Corp. (Taiwan)
Yu Wei Cheng, United Microelectronics Corp. (Taiwan)
Simon C. C. Hsu, United Microelectronics Corp. (Taiwan)
Chun Chi Yu, United Microelectronics Corp. (Taiwan)
Nuriel Amir, KLA-Tencor Israel (Israel)
DongSub Choi, KLA-Tencor Korea (Republic of Korea)
Tal Itzkovich, KLA-Tencor Israel (Israel)
Inna Tarshish-Shapir, KLA-Tencor Israel (Israel)
David C. Tien, KLA-Tencor Corp. (United States)
Eros Huang, KLA-Tencor Taiwan (Taiwan)
Kelly T. L. Kuo, KLA-Tencor Taiwan (Taiwan)
Takeshi Kato, Hitachi High-Tech Trading Corp. (Japan)
Osamu Inoue, Hitachi High-Tech Science Corp. (Japan)
Hiroki Kawada, Hitachi High-Tech Science Corp. (Japan)
Yutaka Okagawa, Hitachi High-Tech Science Corp. (Japan)
Luis Huang, Hitachi High-Technologies Taiwan Corp. (Taiwan)
Matthew Hsu, Hitachi High-Technologies Taiwan Corp. (Taiwan)
Amei Su, Hitachi High-Technologies Taiwan Corp. (Taiwan)

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