Current status of EUV mask blanks and LTEM substrates defectivity and cleaning of blanks exposed in EUV ADT

Kadaksham, Arun John; Lee, Byunghoon; House, Matt; Laursen, Thomas; Niekrewicz, Brian; Rastegar, Abbas

doi:10.1117/12.880757

Cited by 11 publications

(7 citation statements)

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“…However, past experience has shown that it is a great challenge for the blank vendors to achieve such a goal with any reasonable blank yield. [1][2][3][4] In fact, ML blanks with zero defect at sizes ≥50nm has never been demonstrated even for a champion ML blank by the blank vendors so far. If we have a ML blank with only a few printable defects, can we use these blanks to fabricate a mask and still yield a defect-free mask?…”

Section: Introductionmentioning

confidence: 87%

EUVL multilayer mask blank defect mitigation for defect-free EUVL mask fabrication

et al. 2012

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For Extreme Ultra-violet Lithography (EUVL) targeting at 11nm and beyond design rules, the minimum printable EUVL multilayer (ML) mask defect size can be as small as 20-25nm. As a result, the defect-free EUVL ML mask blank fabrication remains the top challenge for EUVL mask. Aspects of this challenge include high quality blank substrate material (low thermal expansion material) fabrication, substrate polishing, substrate cleaning, blank handling, ML deposition, and high sensitivity substrate and blank defect inspection. High investment cost and potential low blank yield due to stringent defect-free requirement can quickly drive up EUVL cost of ownership. It is anticipated, however, the EUVL ML blank yield can be drastically improved if we can allow a few defects on a ML blank. Utilizing such a "defective" grade mask blank to fabricate a defect-free EUVL mask requires several defect mitigation schemes during mask patterning processes. These schemes include modifying mask absorber pattern via repair tool to compensate the effect of an adjacent ML defect and using absorber pattern to cover the ML defects. In this paper, we focused on the study and demonstration of using device pattern to cover limited number of blank defects. The steps of this defect mitigation process include blank fiducial mark patterning, defect location relative to fiducial mark precision measurement, automated pattern shift solution simulation for a given ML defect map, and precision alignment of the device pattern to the blank defects during e-beam write. With these steps, we have successfully demonstrated the coverage of several targeted ML blank defects simultaneously via global device pattern shift.

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Section: Introductionmentioning

confidence: 87%

EUVL multilayer mask blank defect mitigation for defect-free EUVL mask fabrication

et al. 2012

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“…11,12 As a result, defect hiding and defect compensation methods have also been proposed, [13][14][15] which work by modifying the absorber pattern to compensate the aerial image. Detailed defect information, such as the defect position on the mask, the defect size, and the phase distribution, is necessary for the compensation process.…”

Section: Introductionmentioning

confidence: 99%

Phase defect characterization on an extreme-ultraviolet blank mask using microcoherent extreme-ultraviolet scatterometry microscope

Harada¹,

Tanaka²,

Watanabe³

et al. 2013

Journal of Vacuum Science & Technology B, Nanotechnology an

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“…EUV actinic metrology [5][6][7][8][9][10][11] is required to evaluate the actinic feature of defect printability and the critical dimension (CD). In addition, an EUV image depends on the incidence angle to the mask because an absorber causes shadows and reflections of EUV at the 3D sidewall structure.…”

Section: Introductionmentioning

confidence: 99%

Extreme ultraviolet mask observations using a coherent extreme ultraviolet scatterometry microscope with a high-harmonic-generation source

Fujino

Tanaka

Harada

et al. 2015

Jpn. J. Appl. Phys.

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In extreme ultraviolet (EUV) lithography, the three-dimensional structure of an EUV mask, which has an absorber layer and a Mo/Si multilayer on a glass substrate, strongly affects the EUV phase. We have developed a coherent EUV scatterometry microscope (CSM) to observe EUV patterns with a quantitative phase contrast based on the coherent-diffraction-imaging method, which is a simple system without an objective. A coherent stand-alone high-harmonic-generation (HHG) EUV source has been developed for practical use. Although the throughput of the relay optics in the previous study was insufficient to compensate for the fluctuation of the beam position, herein the beam position is stabilized and the relay optics are upgraded, increasing the throughput of the EUV power 130-fold. Consequently, the detection time for the same defect size is markedly reduced from 1000 to 1 s. Furthermore, a 52 ' 52 nm 2 absorber defect is detected in 10 s.

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Current status of EUV mask blanks and LTEM substrates defectivity and cleaning of blanks exposed in EUV ADT

Cited by 11 publications

References 0 publications

EUVL multilayer mask blank defect mitigation for defect-free EUVL mask fabrication

EUVL multilayer mask blank defect mitigation for defect-free EUVL mask fabrication

Phase defect characterization on an extreme-ultraviolet blank mask using microcoherent extreme-ultraviolet scatterometry microscope

Extreme ultraviolet mask observations using a coherent extreme ultraviolet scatterometry microscope with a high-harmonic-generation source

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