Accuracy and Repeatability of X-Ray Metrology
- Bede plc, Belmont Business Park, Durham DH1 1TW (United Kingdom)
All metrology tools must make a trade-off between data quality and wafer throughput. Moreover, most X-ray metrology may be performed on regions inside the scribe lines. This paper discusses the appropriate choices of trade-offs for throughput, repeatability and spot size, choosing examples from silicon-germanium composition and thickness metrology. The repeatability varies from 0.7% to 0.1% 1{sigma} with data collection cycles between 20 s and 1000 s. We show that for most of the parameters determined by X-rays the metrology is absolute, and that both accuracy and tool matching is achieved by traceable calibration of the X-ray wavelength and the angle encoders on the tools. Tool matching achieved by this absolute approach to metrology is typically 0.2% in thickness and 0.05% in composition for Si-20%Ge layers {approx} 50 nm thick. For 30 nm metal or dielectric layers measured within a 100 mm scribe line, 0.65% 1{sigma} repeatability is achieved at 150 measurement points/hr and 0.33% at 75 sites/hr.
- OSTI ID:
- 20719276
- Journal Information:
- AIP Conference Proceedings, Vol. 788, Issue 1; Conference: 2005 international conference on characterization and metrology for ULSI technology, Richardson, TX (United States), 15-18 Mar 2005; Other Information: DOI: 10.1063/1.2063026; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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