Advanced NLD mask dry etching system for 90-nm node technology

Harashima, Noriyuki; Sasaki, Takaei; Kuwahara, Kazuhiro; Hayashi, Toshio; Tanaka, Yoshiyuki; Yoshioka, Nobuyuki; Hara, Mutsumi; Ohkubo, Yasushi

doi:10.1117/12.504200

Cited by 3 publications

(1 citation statement)

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“…For the photomask on Figure 3, the resist thickness after etch measured using a profilometer is about 150 nm on l2.5 micron feature, but about 118 and 64 nm for 300 and 100 nm features, as shown in Cr resist resist resist similar resist profile after Cr etch even thought extent is different. [5][6][7][8][9][10][11] It is obvious that the final Cr CD mean value and uniformity are mostly determined by resist erosion. Although resist and Cr profiles of the optimal process are significantly better than those on Figure 3, photoresist soft mask for the whole Cr layer etch contributes most etch CD bias and non-uniformity, and need improvement in order to obtain a more accurate Cr layer CDs.…”

Section: Mean-to-target and Uniformitymentioning

confidence: 99%

65-nm node photomask etching with zero CD process bias

Chen

Markovitz

et al. 2005

SPIE Proceedings

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A robust photomask etching process was studied and developed for 65 nm node photomask production with zero CD process bias. The fabrication process, including pattern generation and transfer do not use data sizing, saving photomask delivery time, improving yield, and reducing fabrication costs. The photomask patterns, without using data sizing cover chrome loads from about 1 percent to 80 percent. For 65 nm critical layer EAPSM, the CD bias of Cr and MoSi etching together is equal to or less than about 20 nm for high and low load photomasks. The etch process and dose adjustment on the 50 keV e-beam writer allow for zero CD process bias, i.e. the data sizing becomes unnecessary in the 65 nm node photomask fabrication. The SMIF pot utilization in both pattern generation and transfer processes significantly improved the defectivity control. Cr and MoSi etch endpoints of 1% load photomasks were clearly detected. Point-to-point CD etch contributions for dark and clear features are 5 nm (3 sigma) or less and final CD value ranges are 8 nm or less. CD etch linearity and other etch properties on SRAF and serif are also discussed. An equation was proposed for calculating phase angle non-uniformity distribution, and phase angle range can be controlled in the range of 1.4 0.3 degree. "Selfmask", i.e. using AR sub-layer as hard mask for beneath chromium sub-layer etch was also discussed.

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Section: Mean-to-target and Uniformitymentioning

confidence: 99%

65-nm node photomask etching with zero CD process bias

Chen

Markovitz

et al. 2005

SPIE Proceedings

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Photomask plasma etching: A review

Wu¹

2006

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

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Investigation of etching properties of metal nitride/high-k gate stacks using inductively coupled plasma Photomask plasma etching was thoroughly reviewed over wide topics including history, equipment, etchant, absorbers, phase shifters, thermodynamics, and kinetics. Plasma etch obtained industrial applications for photomask fabrication in the 1990s and presently is a critical fabrication step for the "enabling" photomask industry. Among all types of photomasks ͑binary, embedded attenuated phase-shift mask, and alternating aperture phase-shift mask͒, chromium ͑Cr͒ containing material etching has been the basis and fundamental for all photomask etches. The main technological challenges for Cr etch occur on ͑isolated͒ dark features of a high load photomask due to the etch critical dimension ͑CD͒ bias dependence on the local loading. It determines the CD features on the Cr layer, phase shifter MoSi layer, and fused silica ͑quartz͒ layer. The CD deviation on pattern layers from the nominal value has been a challenge, especially for the Cr state-of-the-art 65 nm node photomasks even though data sizing exists. Inductively coupled plasma plus bias power using radio frequency wavelength is the dominant configuration of the photomask plasma etcher, with improved loading and CD mean-to-target potential. Thermodynamic applications ͑Gibbs energy minimization method͒ on photomask plasma etch provide a quick, easy, and low cost method to estimate the plasma etch feasibility and defect reduction at different plasma gas input conditions. Empirical relationships between operational parameters and etch properties significantly improve the only design of experiment procedure for etch process optimization.

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