Paper
1 July 2002 Ultrahigh-accuracy measurement of the coefficient of thermal expansion for ultralow-expansion materials
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Abstract
Microlithographic systems rely on precision alignment and a high-level of dimensional stability to achieve required performance. In critical applications, immunity to thermally induced dimensional changes is achieved by the use of low linear coefficient of thermal expansion (hereafter referred to as CTE and denoted by a) materials such as ULE in components such as reflective optics and machine structures. ULE has a CTE that is typically in the 0 + 30 ppb K-1 range and it may be engineered to achieve a specific value. A high-accuracy determination of the CTE is essential for both process control and for providing an essential input to the design of such systems for error budgeting purposes. Currently, there is a need for CTE determination with an expanded uncertainty U(a)(k=2) < 1 ppb K-1 in the 273-373 K temperature range. A survey of the state-of-the-art of high-accuracy absolute measurement of CTE is presented along with a discussion of the significant error sources in each of the current techniques. The metrology techniques, sample design and instrumentation are described along with uncertainty estimates for representative instruments. The design philosophy and prospects for a new instrument that satisfies the above mentioned need are described.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Vivek G. Badami and Michael Linder "Ultrahigh-accuracy measurement of the coefficient of thermal expansion for ultralow-expansion materials", Proc. SPIE 4688, Emerging Lithographic Technologies VI, (1 July 2002); https://doi.org/10.1117/12.472323
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Cited by 14 scholarly publications and 1 patent.
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KEYWORDS
Temperature metrology

Interferometers

Error analysis

Metrology

Thermography

Fabry–Perot interferometers

Optical coatings

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