Patterning 45nm flash/DRAM contact hole mask with hyper-NA immersion lithography and optimized illumination

Chen, Ting; Broeke, Doug Van Den; Hsu, Stephen; Park, Sang-Bong; Berger, Gabriel; Coskun, Tamer H.; Vocht, Joep De; Corcoran, Noel; Chen, Fung; Heijden, E. van der; Finders, Jo; Engelen, André; Socha, Robert

doi:10.1117/12.656982

Cited by 1 publication

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“…In order to average ellipticities correctly, the measurement algorithm has to take into account the magnitude of the CH distortion and the angle of the distortion. Contact hole ellipticity has been defined as: [ 1 ] a = long axis ellipse, b = short axis ellipse ( Figure 2). …”

Section: Figure 1bmentioning

confidence: 99%

MacroCD contact ellipticity measurement for lithography tool qualification

Englard¹,

Setten

Janssen

et al. 2007

SPIE Proceedings

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Contact hole integrity is an important metric for IC manufacturers, which is reflected in tight ellipticity control as part of the lithography tool qualifications. The current ellipticity measurement methodology is very sensitive to random process variations of the contact hole shape. Determining ellipticity in a systematic manner poses a challenge on qualification productivity, as acquiring more data for statistical validity leads to unacceptably long measurement times. The introduction of the so-called MacroCD Vector measurement enables a single shot large sampling of contact holes, including vector calculation and averaging of all individual contact ellipticity results within the MacroCD measurement array. Based on these enhanced measurement features, it is shown that contact hole ellipticity can be determined with much higher accuracy while local, mostly process induced variations can be characterized simultaneously. This opens possibilities to study correlation between ellipticity and possible root causes in the litho process module.

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Section: Figure 1bmentioning

confidence: 99%