TY - JOUR
T1 - Dual-phase virtual metrology scheme
AU - Cheng, Fan Tien
AU - Huang, Hsien Cheng
AU - Kao, Chi An
N1 - Funding Information:
Manuscript received March 19, 2007; revised July 27, 2007. This work was supported in part by the National Science Council of the Republic of China under Contract NSC95-2622-E-006-002. The authors are with the Institute of Manufacturing Engineering, National Cheng Kung University Tainan, Taiwan, R.O.C. (e-mail: chengft@mail.ncku. edu.tw). Color versions of some of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TSM.2007.907633
PY - 2007/11
Y1 - 2007/11
N2 - This paper proposes a dual-phase virtual metrology scheme. To consider both promptness and accuracy, this scheme generates dual-phase virtual metrology (VM) values. Phase I emphasizes promptness, that is to immediately calculate and output the Phase-I VM value (denoted ) of a workpiece (wafer or glass) once the entire process data of the workpiece are completely collected. Phase II improves accuracy, that is not to recalculate and output the Phase-II VM values (denoted) of all the workpieces in the cassette (also called FOUP in the semiconductor industry) until an actual metrology value (required for tuning or retraining purposes) of a workpiece in the same cassette is collected. Also, in this scheme, the accompanying reliance index (RI) and global similarity index (GSI) of each and are also generated. The RI and GSI are applied to gauge the degree of reliance. If the reliance level of a VM value is lower than the threshold, this VM value may not be adopted. An illustrative example involving fifth-generation thin-film transistor liquid crystal display (TFT-LCD) chemical-vapor deposition equipment is presented. Experimental results demonstrate that the proposed scheme is applicable to the wafer-to-wafer or glass-to-glass advanced process control for semiconductor or TFT-LCD factories.
AB - This paper proposes a dual-phase virtual metrology scheme. To consider both promptness and accuracy, this scheme generates dual-phase virtual metrology (VM) values. Phase I emphasizes promptness, that is to immediately calculate and output the Phase-I VM value (denoted ) of a workpiece (wafer or glass) once the entire process data of the workpiece are completely collected. Phase II improves accuracy, that is not to recalculate and output the Phase-II VM values (denoted) of all the workpieces in the cassette (also called FOUP in the semiconductor industry) until an actual metrology value (required for tuning or retraining purposes) of a workpiece in the same cassette is collected. Also, in this scheme, the accompanying reliance index (RI) and global similarity index (GSI) of each and are also generated. The RI and GSI are applied to gauge the degree of reliance. If the reliance level of a VM value is lower than the threshold, this VM value may not be adopted. An illustrative example involving fifth-generation thin-film transistor liquid crystal display (TFT-LCD) chemical-vapor deposition equipment is presented. Experimental results demonstrate that the proposed scheme is applicable to the wafer-to-wafer or glass-to-glass advanced process control for semiconductor or TFT-LCD factories.
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U2 - 10.1109/TSM.2007.907633
DO - 10.1109/TSM.2007.907633
M3 - Article
AN - SCOPUS:38949143586
SN - 0894-6507
VL - 20
SP - 566
EP - 571
JO - IEEE Transactions on Semiconductor Manufacturing
JF - IEEE Transactions on Semiconductor Manufacturing
IS - 4
M1 - 4369327
ER -