发明名称 |
Overlay target and measurement procedure to enable self-correction for wafer-induced tool-induced shift by imaging sensor means |
摘要 |
Imaging instruments for inspecting products, such as semiconductor chips, are calibrated by providing a reference test structure having features which can be located by optical measurements not subject to tool-induced shift and wafer-induced shift experienced by the imaging instrument, thereby enbabling self correction of the imaging instrument. The reference test structure, which has a plurality of target units formed therein, is first qualified using the optical measurements, and is then used to calibrate the imaging instrument. The optical measurements may be made by a supplementary alternative imaging-sensor means which can be integrated into existing imaging instrument architecture. A series of test structure elements may be fabricated with one component of each being spaced at progressively greater distances from an arbitrary baseline, such that a zero overlay element may be identified by the alternative imaging sensor means.
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申请公布号 |
US5923041(A) |
申请公布日期 |
1999.07.13 |
申请号 |
US19950428036D |
申请日期 |
1995.04.25 |
申请人 |
CRESSWELL, MICHAEL WILLIAM;LINHOLM, LOREN WENDELL;ALLEN, RICHARD A. |
发明人 |
CRESSWELL, MICHAEL WILLIAM;LINHOLM, LOREN WENDELL;ALLEN, RICHARD A. |
分类号 |
G01R31/311;G03F7/20;(IPC1-7):G01B11/00 |
主分类号 |
G01R31/311 |
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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