Improvements in MoSi EAPSM CD bias and iso-dense linearity plasma etch results utilizing design of experiments process optimization of Gen III ICP plasma source

Plumhoff, Jason; Constantine, C.; Shin, Jong Gye; Rausa, Emmanuel

doi:10.1117/12.476973

Cited by 3 publications

(2 citation statements)

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“…As a starting point, a standard SF 6 -based MoSi etch recipe was adapted for the ME-V. 3 Utilizing the n&k 1700-RT, it was possible to quickly run several experiments to study the phase uniformity response to several processes. Radial nonuniformity was the primary area of interest, as linear non-uniformities can be easily corrected on the ME-V after a process has been developed.…”

Section: A Initial Mosi Process Development -Phase Uniformitymentioning

confidence: 99%

Phase shift mask etch process development utilizing a scatterometry-based metrology tool

Plumhoff

Gray

2008

SPIE Proceedings

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Phase, along with defect levels and CD, must be closely monitored on 45nm technology node masks. The final phase shift of a mask is highly dependent on the ability of the etch tool to stop at precisely the correct depth. Developing etch processes and endpoint recipes for successful phase shift processing depends on rapid and accurate measurement of etch depth. In many mask shops, these measurements are made by either direct phase measurement tools or atomic force microscopes (AFM). These tools have relatively low throughput. In the case of the direct phase measurement tool, the large measurement spot size precludes the measurement of the small features most interesting to mask makers. A need exists for a relatively fast measurement tool that can be applied to features <1µm in size.As part of Oerlikon USA's continuous etch process improvement efforts, the etch depth measurement capabilities of a scatterometry based metrology tool were explored. Phase shift masks (one EAPSM, one AAPSM) were created to act as standards for our experiments. Regions of each mask were etched to various depths using an Oerlikon Mask Etcher system, and then measured with both a commercial AFM and an n&k Technology 1700-RT scatterometry tool. Using this data, recipes capable of measuring quartz trench features, partially-etched MoSi trench features, and bulk MoSi films were developed on the n&k 1700-RT. Phase uniformity data taken from actual etch experiments will be provided, as well as data showing the repeatability of each system, and a comparison of the relative measurement times.

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Section: A Initial Mosi Process Development -Phase Uniformitymentioning

confidence: 99%

Phase shift mask etch process development utilizing a scatterometry-based metrology tool

Plumhoff

Gray

2008

SPIE Proceedings

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“…However, mask absorber errors are inevitably introduced by the imperfect etching process in mask fabrication and measurement [10,11]. In addition, the MAT error and tapered SWA deformation of the absorber are increased by repeated mask cleaning process [12,13]. Recently, Sturtevant et al and Rudolph et al studied the impact of photomask uncertainties on computational lithography [4,14,15].…”

Section: Introductionmentioning

confidence: 99%

Mitigating the Impact of Mask Absorber Error on Lithographic Performance by Lithography System Holistic Optimization

Sheng

Sun

et al. 2019

Applied Sciences

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The non-ideal mask absorber can cause an increase in critical dimension error (CDE) and decrease in process window (PW). However, the random mask absorber errors induced during mask fabricating and measuring are not considered in computational lithography. The problem cannot be neglected as the continuous scaling of lithography technology node. In this work, for the first time to our knowledge, a source, numerical aperture (NA), and process parameters co-optimization (SNPCO) method is developed to reduce the CDE induced by absorber errors and improve the PW. First, the source is represented by Zernike polynomials to balance computational burden and flexibility of source. Then a weighted cost function containing CDE and PW that incorporates the influences of absorber errors is created. Finally, a statistical optimization method is used to optimize the lithographic system parameters. Simulations of 1D mask pattern show that for the system with extreme absorber errors, the pattern errors of the proposed method are reduced by 62.1% and 58.9%, and the PWs are increased by 40.3% and 36.4%, respectively. The results illustrate that this method is effective in mitigating the CDE caused absorber errors and improving process robustness.

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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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Improvements in MoSi EAPSM CD bias and iso-dense linearity plasma etch results utilizing design of experiments process optimization of Gen III ICP plasma source

Cited by 3 publications

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Phase shift mask etch process development utilizing a scatterometry-based metrology tool

Phase shift mask etch process development utilizing a scatterometry-based metrology tool

Mitigating the Impact of Mask Absorber Error on Lithographic Performance by Lithography System Holistic Optimization

Photomask plasma etching: A review

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