1. Processing of Endpoint Information from HAR Vias
PBS&T
Processing of Endpoint Information from HAR Vias
Valery Ray
EFUG 2006, Wuppertal, Germany

2. Outline Mechanism of HAR Endpoint Detection
Distribution of Endpoint Information
Example of Spatial Filtering
Summary
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3. HAR Endpoint Mechanism: Negative Wall Charge
ILD
Metal Line
Negative charge on sidewalls
Based on assumption of negative wall charging induced by FIB within HAR via.
Proposed by T. Lindquist
ISTFA 2004
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4. HAR Endpoint Mechanism: Metal Redeposition
Based on assumption of re-deposition of metal from conductor on walls of HAR via
Proposed by V. Ray
ISTFA 2005
Sidewall redeposit
ILD
ILD
Metal Line
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5. Observation of Endpoint Details
Endpoint image of via with 10:1 aspect ratio
FOV 1µm IBeam 5 pA
Spatial distribution of information is evident
Spatial Filtering Window
Excluded Area
Integration Window
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6. Integration and Filtering
Spatially Filtered Endpoint
S/N Improvement by Factor ~2
Integrated Endpoint
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7. Summary
HAR Endpoint Information is available primarily on periphery of the via.
Spatial filtering excludes ~ 80% of dwell points in center of the via from integration.
Use of spatial filtering improves S/N of endpoint detection graph by factor ~ 2.
Technique is equally applicable to sample current and secondary electron endpoint detection.
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8.
EFUG 2006, Wuppertal, Germany