Design and test of a through-the-mask alignment sensor for a vertical stage x-ray aligner

Nelson, Mike; Kreuzer, J. L.; Gallatin, Gregg M.

doi:10.1116/1.587508

Cited by 8 publications

(3 citation statements)

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“…The aligner has two wafer alignment systems: ͑1͒ the through-the-mask ͑TTM͒ alignment sensor 3 optical design as the Micrascan ϩ -II's Axiom wafer alignment system. 4 The TTM alignment sensor has successfully acquired wafer alignment signals but have not yet been integrated into the aligner's system control software.…”

Section: A Test Methodologymentioning

confidence: 99%

Overlay performance of 180 nm ground rule generation x-ray lithography aligner

Chen

1997

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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The 180 nm ground rule production prototype x-ray lithography aligner was developed for the Defense Advanced Lithography Program (DALP) and installed in IBM’s Advanced Lithography Facility (ALF) in 1995. This aligner is designed to satisfy the manufacturing requirement for 250 and 180 nm ground rule electronic devices, such as 256 Mbit and 1 Gbit dynamic random access memories. The acceptance evaluation of this aligner was presented elsewhere (Ref. 12). The aligner uses an innovative x-ray image sensor (XRIS) to align the mask by detecting its x-ray actinic image and uses an off-axis alignment system, similar to the alignment system used in Micrascan-II™ (a trademark of Silicon Valley Group Lithography), to align the wafer. From subsystem testing, the alignment repeatability of XRIS is not a significant contributor to the aligner’s contribution of overlay error. As a result, the x-ray alignment sensor technology can be used for future generations of x-ray lithography aligners. This article will specifically focus on the overlay performance of the aligner. The overlay evaluation consisted of careful wafer stage and alignment system calibration, off-line subsystem testing, and extensive exposure tests. The exposure tests were designed to measure the alignment performance of the aligner across a wide range of wafer structure types. A detailed discussion is given on the test methodology and the aligner contribution to the total overlay error. On the better levels (e.g., etched Si), the tool-to-itself aligner contribution to overlay error is in the range of 35–40 nm (mean+3σ) and approaches the overlay error budget for a 180 nm ground rule generation x-ray aligner. An overlay model was also developed to include the error contributions of the aligner as well as the image placement accuracy of the mask. The modeling results show that the aligner, with image placement errors of current x-ray masks, can satisfy the overlay requirement (mean+3σ<70 nm) for 1 Gbit device demonstration programs.

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Section: A Test Methodologymentioning

confidence: 99%

Overlay performance of 180 nm ground rule generation x-ray lithography aligner

Chen

1997

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…These and also more recent refinements with e.g. chirped gratings [110][111][112][113] have mostly been motivated by applications in X-ray proximity lithography but are also, in principle, compatible with UV proximity lithography. Nevertheless, probably due to significant increase in complexity (e.g.…”

Section: Wedge Error Compensationmentioning

confidence: 98%

High-resolution proximity lithography for nano-optical components

Stuerzebecher

Fuchs

Zeitner

et al. 2015

Microelectronic Engineering

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“…[1][2][3][4][5][6][7][8][9][10] Those that employ marks on mask and substrate, facing one another across the mask-substrate gap, can be grouped into amplitude-sensitive and phase-sensitive schemes. [1][2][3][4][5][6][7][8][9][10] Those that employ marks on mask and substrate, facing one another across the mask-substrate gap, can be grouped into amplitude-sensitive and phase-sensitive schemes.…”

Section: Introductionmentioning

confidence: 99%

Immunity to signal degradation by overlayers using a novel spatial-phase-matching alignment system

Moon¹

1995

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Articles you may be interested inAg2Te/As2S3: A high-contrast, top-surface imaging resist for 193 nm lithography J.Preliminary results from a prototype projection electron-beam stepper-scattering with angular limitation projection electron beam lithography proof-of-concept systemWe describe improvements to the interferometric broad-band imaging alignment scheme introduced in 1993. Alignment is signified by matching, across the midline of a charge-coupled device, the spatial phase of interference fringes formed by diffraction from complementary marks on mask and substrate. Image contrast is enhanced by back diffraction from hatched alignment marks on the substrate. Overlayers of resist, polysilicon, and aluminum have negligible effect on interferometric broad-band imaging alignment; they alter image contrast but not spatial phase. Novel alignment marks that incorporate four gratings increase the capture range to several tens of micrometers. By spatial filtering in the back focal plane of the alignment microscope, mask-sample gap may be determined from the resulting spatial phase shift. An alignment system for x-ray nanolithography ͑XLS-4͒ that incorporates the interferometric broad-band imaging scheme has been constructed.

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Design and test of a through-the-mask alignment sensor for a vertical stage x-ray aligner

Cited by 8 publications

References 0 publications

Overlay performance of 180 nm ground rule generation x-ray lithography aligner

Overlay performance of 180 nm ground rule generation x-ray lithography aligner

High-resolution proximity lithography for nano-optical components

Immunity to signal degradation by overlayers using a novel spatial-phase-matching alignment system

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