Title
Deep sub-wavelength metrology for advanced defect classification
Author
van der Walle, P.
Kramer, E.
van der Donck, J.C.J.
Mulckhuyse, W.F.W.
Nijsten, L.
Bernal Arango, F.A.
de Jong, A.
van Zeijl, E.
Spruit, W.E.T.
van den Berg, J.H.
Nanda, G.
van Langen-Suurling, A.K.
Alkemade, P.F.A.
Pereira, S.F.
Maas, D.J.
Publication year
2017
Abstract
Particle defects are important contributors to yield loss in semi-conductor manufacturing. Particles need to be detected and characterized in order to determine and eliminate their root cause. We have conceived a process flow for advanced defect classification (ADC) that distinguishes three consecutive steps; detection, review and classification. For defect detection, TNO has developed the Rapid Nano (RN3) particle scanner, which illuminates the sample from nine azimuth angles. The RN3 is capable of detecting 42 nm Latex Sphere Equivalent (LSE) particles on XXX-flat Silicon wafers. For each sample, the lower detection limit (LDL) can be verified by an analysis of the speckle signal, which originates from the surface roughness of the substrate. In detection-mode (RN3.1), the signal from all illumination angles is added. In review-mode (RN3.9), the signals from all nine arms are recorded individually and analyzed in order to retrieve additional information on the shape and size of deep sub-wavelength defects. This paper presents experimental and modelling results on the extraction of shape information from the RN3.9 multi-azimuth signal such as aspect ratio, skewness, and orientation of test defects. Both modeling and experimental work confirm that the RN3.9 signal contains detailed defect shape information. After review by RN3.9, defects are coarsely classified, yielding a purified Defect-of-Interest (DoI) list for further analysis on slower metrology tools, such as SEM, AFM or HIM, that provide more detailed review data and further classification. Purifying the DoI list via optical metrology with RN3.9 will make inspection time on slower review tools more efficient.
Subject
Particle contamination
Defect detection
Defect review
Advanced defect classification
Semiconductor
Latex sphere equivalent
Dark field microscopy
Speckle
High Tech Systems & Materials
Industrial Innovation
Nano Technology
NI - Nano Instrumentation OPT - Optics
TS - Technical Sciences
To reference this document use:
http://resolver.tudelft.nl/uuid:1ceeadc1-22fe-495b-9042-a6361b6543bc
TNO identifier
777006
Publisher
SPIE
Source
SPIE Optical Metrology 2017, Munich, Germany, 26–29 June 2017
Document type
conference paper