发明名称 |
Diffracting, aperiodic targets for overlay metrology and method to detect gross overlay |
摘要 |
A method for measuring overlay in semiconductor wafers includes a calibration phase in which a series of calibration samples are analyzed. Each calibration sample has an overlay that is known to be less than a predetermined limit. A difference spectrum for a pair of reflectively symmetric overlay targets is obtained for each calibration sample. The difference spectra are then combined to define a gross overlay indicator. In subsequent measurements of actual wafers, difference spectra are compared to the overlay indicator to detect cases of gross overlay.
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申请公布号 |
US7230704(B2) |
申请公布日期 |
2007.06.12 |
申请号 |
US20040858691 |
申请日期 |
2004.06.02 |
申请人 |
TOKYO ELECTRON LIMITED |
发明人 |
SEZGINER ABDURRAHMAN;HUANG HSU-TING;JOHNSON KENNETH |
分类号 |
G01B11/00;G01N21/47;G03F7/20 |
主分类号 |
G01B11/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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