Ultrahigh-accuracy measurement of the coefficient of thermal expansion for ultralow-expansion materials

Badami, Vivek; Linder, Michael

doi:10.1117/12.472323

Cited by 22 publications

(10 citation statements)

References 29 publications

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“…Thermal expansivity and hydro-thermal strain may be measured in various ways, reviewed by James et al [6], but the most common procedure is mechanical dilatometry [7]. In order to very accurately measure the linear thermal expansion coefficient of precision items such as gauge blocks, optical interferometer based wavelength measurements [8], and interferometric dilatometetry [9], have been used to obtain deformation values. A displacement measuring interferometeric system using a heterodyne scheme [10], is another technique that provides high accuracy.…”

Section: Introductionmentioning

confidence: 99%

Measurement of thermal elongation induced strain of a composite material using a polarization maintaining photonic crystal fiber sensor

Ramakrishnan¹,

Rajan

Semenova³

et al. 2013

Sensors and Actuators A: Physical

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Section: Introductionmentioning

confidence: 99%

Measurement of thermal elongation induced strain of a composite material using a polarization maintaining photonic crystal fiber sensor

Ramakrishnan¹,

Rajan

Semenova³

et al. 2013

Sensors and Actuators A: Physical

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“…Measurement of CTE to the tolerances required by SEMI P37-1101 is challenging, and suppliers are developing methods with the required accuracy, precision and spatial resolution. 9 The requirements for spatial resolution of the CTE measurement have not been definitively set, but resolution on the order of 1 cm is probably required.…”

Section: Mask Substratesmentioning

confidence: 99%

EUVL masks: requirements and potential solutions

Hector

2002

Emerging Lithographic Technologies VI

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Extreme ultraviolet lithography (EUVL) is a leading next generation lithography technology. Significant progress has been made in developing mask fabrication processes for EUVL. The mask blank for EUVL consists of a low thermal expansion material substrate having a square photomask form factor that is coated with Mo/Si multilayers. A SEMI standard is now available for mask substrates. SEMI standards are also being developed for mask mounting, for mask blank multilayers and absorbers and for mask handling and storage. Several commercial suppliers are developing polishing processes for LTEM substrates, and they are progressing toward meeting the requirements for flatness, surface roughness, and defects defined in the SEMI standard.One of the challenges in implementing EUVL is to economically fabricate multilayer-coated mask blanks with no printable defects. Significant progress has been made in developing mask blank multilayer coating processes with low added defect density. Besides lowering added defect density, methods to reduce defect printability are being developed to effectively enable repair of many defect types. These repair processes might significantly increase yield of EUV mask blanks before defect density is lowered to production targets. Calculations of EUVL mask cost indicate that defect repair processes could allow the initial defect density targets for mask blanks to be relaxed.The mask patterning process for EUVL is nearly the same as that for conventional binary optical lithography masks. EUVL mask patterning efforts are focused on developing the EUV-specific aspects of the patterning process. Eight absorbers have been evaluated against the requirements for EUVL masks, and two absorbers-TaN and Cr--will probably meet the requirements after some further development.

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“…5 This resolution is higher than those obtained by conventional CTE evaluation techniques. 1,6,7 Two-dimensional information of the LSAW velocities reflects the substrate surface characteristics which play a very important role for the reflective optics in the EUVL systems. Therefore the CTE evaluation using the LFB-UMC system has a great advantage compared with the conventional methods measuring averaged characteristics along the thickness direction of the substrate.…”

Section: Introductionmentioning

confidence: 99%

Striae evaluation of TiO 2 -SiO 2 ultra-low expansion glasses using the line-focus-beam ultrasonic material characterization system

2006

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Super accurate evaluation method for TiO 2 -doped SiO 2 ultra-low-expansion glass having periodic striae associated with its fabrication process was investigated using the line-focus-beam ultrasonic material characterization (LFB-UMC) system. To obtain absolute values of leaky surface acoustic wave (LSAW) velocities measured with the LFB-UMC system, proper standard specimens of the glass for system calibration was examined. Using a specimen with a surface perpendicular to the striae plane as the standard specimen, a reliable standard LSAW velocity of 3308.18 m/s within ±0.35 m/s for the calibration was obtained regardless of influence of velocity variations due to the periodic striae. Also, we determined the accurate relationship between the TiO 2 concentrations and LSAW velocities (sensitivity: -0.0601 wt%/(m/s)) so that the TiO 2 concentration of the standard specimen with a LSAW velocity of 3308.18 m/s was determined to be 7.09 wt%. Furthermore, to evaluate more reliably the more homogeneous ultra-low-expansion glasses in the near future, the measurement accuracy of the LSAW velocity was improved with a method using the LFB device with a larger curvature radius R operating at lower frequency from ±0.0053% for R=1.0 mm at 225 MHz to ±0.0020% for R=2.0 mm at 75 MHz.

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Ultrahigh-accuracy measurement of the coefficient of thermal expansion for ultralow-expansion materials

Cited by 22 publications

References 29 publications

Measurement of thermal elongation induced strain of a composite material using a polarization maintaining photonic crystal fiber sensor

Measurement of thermal elongation induced strain of a composite material using a polarization maintaining photonic crystal fiber sensor

EUVL masks: requirements and potential solutions

Striae evaluation of TiO 2 -SiO 2 ultra-low expansion glasses using the line-focus-beam ultrasonic material characterization system

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