Title
Large dynamic range Atomic Force Microscope for overlay improvements
Author
Kuiper, S.
Fritz, E.C.
Crowcombe, W.E.
Liebig, T.
Kramer, G.F.I.
Witvoet, G.
Duivenvoorde, T.
Overtoom, A.J.
Rijnbeek, R.A.
van Zwet, E.J.
van Dijsseldonk, A.
den Boef, A.
Beems, M.
Levasier, L.
Contributor
Sanchez, M.I. (editor)
Ukraintsev, V.A. (editor)
Publication year
2016
Abstract
Nowadays most overlay metrology tools assess the overlay performance based on marker features which are deposited next to the functional device features within each layer of the semiconductor device. However, correct overlay of the relatively coarse marker features does not directly guarantee correct overlay of the much smaller device features. This paper presents the development of a tool that allows to measure the relative distance between the marker and device features within each layer of the semiconductor device, which can be used to improve the overlay at device feature level. In order to be effective, the marker to device feature distance should be measured with sub-nanometer measurement uncertainty over several millimeters range. Furthermore, the tool should be capable of profiling the marker features to allows prediction of the location interpretation of the optical diffraction based alignment sensors, which are sensitive for potential asymmetry of the marker features. To enable this, a highly stable Atomic Force Microscope system is being developed. The probe is positioned relative to the wafer with a 6DOF controlled hexapod stage, which has a relatively large positioning range of 8x8mm. The position and orientation of this stage is measured relative to the wafer using 6 interferometers via a highly stable metrology frame. A tilted probe concept is utilized to allow profiling of the high aspect ratio marker and device features. Current activities are aimed at demonstrating the measurement capabilities of the developed AFM system.
Subject
Nano Technology
OM - Opto-Mechatronics
TS - Technical Sciences
High Tech Systems & Materials
Electronics
Industrial Innovation
AFM
Atomic Force Microscopy
Overlay
Scanning probe microscopy
SPM
Aspect ratio
Semiconductor devices
Silicon wafers
Uncertainty analysis
Units of measurement
Alignment sensors
Functional devices
High aspect ratio
Optical diffractions
Position and orientations
Relative distances
Process control
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http://resolver.tudelft.nl/uuid:37309d0e-df8b-4a85-bc03-d598d1d498a5
TNO identifier
546189
Publisher
SPIE
ISBN
9781510600133
ISSN
0277-786X
Source
30th Conference on Metrology, Inspection, and Process Control for Microlithography, 22-25 February 2016, 9778
Series
Proceedings of SPIE - The International Society for Optical Engineering
Article number
97781B
Document type
conference paper