ZERODUR glass ceramics: strength data for the design of structures with high mechanical stresses

Hartmann, Péter; Nattermann, Kurt; Döhring, Thorsten; Kuhr, M.; Thomas, Peter; Kling, Guenther; Gath, Peter; Lucarelli, Stefano

doi:10.1117/12.788854

Cited by 15 publications

(9 citation statements)

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“…This is often applied for satellite componnents, were lightweighted mirrors have to withstand the high loads during launch. Statistical evaluations on the strength of ZERODUR ® are presented in recent papers 21,22 . …”

Section: Lightweighted Zerodur ® Structuresmentioning

confidence: 99%

“…This is particularly important for SOFIA, since the telescope will operate at altitudes, where the temperature can quickly drop down to minus 60 degrees Celsius. ZERODUR ® is strong enough to handle rough flying conditions and difficult landings with up to a nine fold gravitational force 21,22 . The use of special manufacturing methods enabled SOFIA's developers to reduce the weight of the telescope enough so that it could be practically deployed on an aircraft.…”

Section: Sofia -An Infrared Telescope In An Airplanementioning

confidence: 99%

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Forty years of ZERODUR mirror substrates for astronomy: review and outlook

Döhring

Jedamzik

Thomas

et al. 2008

Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation

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Initiated in 1968 by the first order of the Max-Planck-Institute in Heidelberg the successful history of ZERODUR ® continues now since 40 years. ZERODUR ® zero expansion glass ceramic from SCHOTT has been the material of choice in astronomy for decades, thanks to its special properties such as its extremely high thermal and mechanical stability. Today most of the major modern optical telescopes of the 4 m class and of the 8 m to 10 m class are equipped with ZERODUR ® . For the future several Extremely Large Telescope (ELT) projects are in development, which are designed with even larger primary mirrors ranging from 30 m to 42 m. Also here ZERODUR ® is under consideration. A historical review, the actual status of developments and an outlook to the future is given in this paper.

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Section: Lightweighted Zerodur ® Structuresmentioning

confidence: 99%

Section: Sofia -An Infrared Telescope In An Airplanementioning

confidence: 99%

Forty years of ZERODUR mirror substrates for astronomy: review and outlook

Döhring

Jedamzik

Thomas

et al. 2008

Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation

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“…Strength analysis exhibits more than 30 % of safety margin with respect to a very conservative 10 MPa ultimate value (see [5] and [6] for discussion about ZERODUR® strength). It is noticeable that the solution with peripheral fixation can provide same order of magnitude for optical performance if mass requirement is released.…”

Section: Fig 8 Optimized Mirror Under Gravity -Zfr Zernike Decomposimentioning

confidence: 99%

Highly light-weighted ZERODUR mirrors

Behar-Lafenetre

Lasic

Viale

et al. 2017

International Conference on Space Optics — ICSO 2008

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Due to more and more stringent requirements for observation missions, diameter of primary mirrors for space telescopes is increasing. Difficulty is then to have a design stiff enough to be able to withstand launch loads and keep a reasonable mass while providing high opto-mechanical performance. Among the possible solutions, Thalès Alenia Space France has investigated optimization of ZERODUR® mirrors. Indeed this material, although fragile, is very well mastered and its characteristics well known. Moreover, its thermo-elastic properties (almost null CTE) is unequalled yet, in particular at ambient temperature. Finally, this material can be polished down to very low roughness without any coating. Light-weighting can be achieved by two different means : either optimizing manufacturing parameters or optimizing design (or both). Manufacturing parameters such as walls and optical face thickness have been improved and tested on representative breadboards defined on the basis of SAGEM-REOSC and Thales Alenia Space France expertise and realized by SAGEM-REOSC. In the frame of CNES Research and Technology activities, specific mass has been decreased down to 36 kg/m². Moreover SNAP study dealt with a 2 m diameter primary mirror. Design has been optimized by Thales Alenia Space France while using classical manufacturing parameters -thus ensuring feasibility and costs. Mass was decreased down to 60 kg/m² for a gravity effect of 52 nm. It is thus demonstrated that high opto-mechanical performance can be guaranteed with large highly lightweighted ZERODUR® mirrors.

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“…The unsuitability of the 2 parameter Weibull approach is obvious following figure 8 comparing three data representations for D64 ground and then etched surfaces. In all three cases the data set consists of 67 specimens as first published in 2008 [10]. The x-axis has been extended down to 0.0001 % the probability of failure.…”

Section: Parameter Weibull Distribution 3 Parameter Weibull Distributionmentioning

confidence: 99%

Zero expansion glass ceramic ZERODUR^®roadmap for advanced lithography

2013

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The zero expansion glass ceramic ZERODUR ® is a well-established material in microlithography in critical components as wafer-and reticle-stages, mirrors and frames in the stepper positioning and alignment system. The very low coefficient of thermal expansion (CTE) and its extremely high CTE homogeneity are key properties to achieve the tight overlay requirements of advanced lithography processes. SCHOTT is continuously improving critical material properties of ZERODUR ® essential for microlithography applications according to a roadmap driven by the ever tighter material specifications broken down from the customer roadmaps. This paper will present the SCHOTT Roadmap for ZERODUR ® material property development. In the recent years SCHOTT established a physical model based on structural relaxation to describe the coefficient of thermal expansion's temperature dependence. The model is successfully applied for the new expansion grade ZERODUR ® TAILORED introduced to the market in 2012. ZERODUR ® TAILORED delivers the lowest thermal expansion of ZERODUR ® products at microlithography tool application temperature allowing for higher thermal stability for tighter overlay control in IC production. Data will be reported demonstrating the unique CTE homogeneity of ZERODUR ® and its very high reproducibility, a necessary precondition for serial production for microlithography equipment components. New data on the bending strength of ZERODUR ® proves its capability to withstand much higher mechanical loads than previously reported. Utilizing a three parameter Weibull distribution it is possible to derive minimum strength values for a given ZERODUR ® surface treatment. Consequently the statistical uncertainties of the earlier approach based on a two parameter Weibull distribution have been eliminated. Mechanical fatigue due to stress corrosion was included in a straightforward way. The derived formulae allows calculating life time of ZERODUR ® components for a given stress load or the allowable maximum stress for a minimum required life time.

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ZERODUR glass ceramics: strength data for the design of structures with high mechanical stresses

Cited by 15 publications

References 1 publication

Forty years of ZERODUR mirror substrates for astronomy: review and outlook

Forty years of ZERODUR mirror substrates for astronomy: review and outlook

Highly light-weighted ZERODUR mirrors

Zero expansion glass ceramic ZERODUR^®roadmap for advanced lithography

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ZERODUR glass ceramics: strength data for the design of structures with high mechanical stresses

Cited by 15 publications

References 1 publication

Forty years of ZERODUR mirror substrates for astronomy: review and outlook

Forty years of ZERODUR mirror substrates for astronomy: review and outlook

Highly light-weighted ZERODUR mirrors

Zero expansion glass ceramic ZERODUR®roadmap for advanced lithography

Contact Info

Product

Resources

About

Zero expansion glass ceramic ZERODUR^®roadmap for advanced lithography