New method of optimizing writing parameters in electron beam lithography systems for throughput improvement considering patterning fidelity constraints

Ng, Hoi-Tou; Shen, Ya Ching; Chen, Sheng-Yung; Liu, Chun-Hung; Ng, Philip C. W.; Tsai, Kuen-Yu

doi:10.1117/1.jmm.11.3.033007

Cited by 5 publications

(10 citation statements)

References 25 publications

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“…12 The spot distribution cannot be presented as an analytic solution. 12 The spot distribution cannot be presented as an analytic solution.…”

Section: Patterning Simulation Methodsmentioning

confidence: 99%

“…12 The spot distribution cannot be presented as an analytic solution. 12 Critical dimension and LER, which were obtained from the proposed method, 12 were set as the constraints to meet the ITRS requirements. This simulation method can be divided into two parts including EOS above the resist (EOS part) and under the resist (resist part).…”

Section: Patterning Simulation Methodsmentioning

confidence: 99%

“…Focusing properties such as beam spot size (B ss ), working distance (WD), and depth of focus (DOF) are typical performance indices selected when optimizing the EOS design parameters such as electrode thickness, lens diameter, and electrode voltages. 12 Then, constraints and cost functions related to PF are selected to further optimize the EOS design parameters to obtain acceptable PF. The differences are reduced by adjusting the EOS design parameters until convergence.…”

Section: New Lithography-patterning-fidelity-aware Eos Design Optmentioning

confidence: 99%

“…The boundaries of the writing parameters are found in our previous study 12 and a parameter set in a feasible region is selected. The pixel pitch is 1 nm, the dosage is 70 lC/cm 2 , and the thickness of the PMMA resist is 40 nm.…”

Section: B Selection Of Test Patterns and Initial Writing Parametersmentioning

confidence: 99%

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Lithography-patterning-fidelity-aware electron-optical system design optimization

Chen¹,

Ng²,

Ma³

et al. 2011

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Low-energy electron beam lithography is a promising patterning solution for the 21 nm half-pitch node and beyond due to its high resolution, low substrate damage, and increased resist sensitivities. To ensure a successful electron-optical system (EOS) design, many factors such as focusing properties (FPs) and patterning fidelity (PF) have to be considered. In traditional EOS optimization flow, FPs are typical performance indices selected when optimizing the EOS design parameters. In each numerical iteration, the EOS FP simulation results are compared with specified performance index values. The differences are reduced by adjusting the EOS design parameters until convergence. However, the performance indices related to FPs may have no direct relation to lithography PF, which is judged by the quality of the developed resist patterns. A new EOS design methodology which directly incorporates lithography PF metrics into the optimization flow is proposed. The EOS design parameters are first optimized while meeting the geometric constraints by using the traditional design flow to obtain acceptable FPs. In order to ensure lithography PF, writing patterns are selected and writing parameters are optimized. Then, constraints and cost functions related to PF are selected to further optimize the EOS design parameters to obtain acceptable PF. In each numerical iteration, the simulated lithography patterning results are compared against specified PF metric values. Their differences are reduced by adjusting the EOS design parameters until all constraints are met and PF cost functions are converged. The proposed method is applied to an EOS structure design for a 5 keV electron beam lithography system which includes a single-gate source and a focusing lens. Initial values of EOS design parameters and geometric constraints are selected based on previous studies. A drawn layout for a 22 nm isolated line pattern is used for verifying the lithography PF specifications based on the International Technology Roadmap of Semiconductors. The developed resist pattern after applying the proposed method clearly indicates that the PF is significantly improved from the value of corresponding critical dimension (CD) and the value of gate CD control.

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“…12 The spot distribution cannot be presented as an analytic solution. 12 The spot distribution cannot be presented as an analytic solution.…”

Section: Patterning Simulation Methodsmentioning

confidence: 99%

Section: Patterning Simulation Methodsmentioning

confidence: 99%

Section: New Lithography-patterning-fidelity-aware Eos Design Optmentioning

confidence: 99%

Section: B Selection Of Test Patterns and Initial Writing Parametersmentioning

confidence: 99%

See 2 more Smart Citations

Lithography-patterning-fidelity-aware electron-optical system design optimization

Chen¹,

Ng²,

Ma³

et al. 2011

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

View full text Add to dashboard Cite

show abstract

“…40 In addition, in the 5 keV case at the PMMA resist, previous studies reported that although the dose of 2 C / cm 2 is adequate for patterning a 45 nm line segment with 25 nm probe size, it is not sufficient for good CD control of short line segments. 43 The beam current intensity can be determined by 41 In addition, another study indicated that the dosage requirement of contact holes at the "32 nm node" ͑approximately equivalent to 45 nm half-pitch node with 3 of 4.5 nm͒ is about 30 C / cm 2 and at the "22 nm node" ͑approximately equivalent to 32 nm half-pitch node with 3 of 3.2 nm͒ is about 60 C / cm 2 .…”

Section: B Parameter Considerations For High-throughput Ebdw Under Imentioning

confidence: 99%

In situ beam drift detection using a two-dimensional electron-beam position monitoring system for multiple-electron-beam–direct-write lithography

Chen¹,

Tsai²,

Ng³

et al. 2011

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Articles you may be interested inElectron optics using multipole lenses for a low energy electron beam direct writing system Electron-beam lithography is one of the promising candidates to replace optical projection lithography due to its high resolution and maskless direct-write capability. In order to achieve the throughput requirement for high-volume manufacturing, miniaturized electro-optics elements are utilized to drive massively parallel beams simultaneously. In high-throughput multiple-electron-beam systems, beam positioning drift problems can become quite serious due to several factors such as thermal distortion and fabrication errors of electron optics. In single-beam systems, periodic recalibration with reference markers on the wafer can be utilized to achieve beam placement accuracy. This technique is not easy for multiple-beam systems. In this article, an innovative in situ two-dimensional electron-beam position monitoring system for multiple-electron-beam lithography is studied. An array of miniaturized electron detectors to measure scattered electrons from the substrate is placed above the wafer. It is assumed that the detector array signals are correlated with the distribution of electron trajectories, and the change of trajectory distortion due to the beam drift can be predicted by Monte Carlo electron-scattering simulation. A standard quadrant detection ͑SQD͒ method and a linear least-squares ͑LLS͒ method are used to estimate the beam drift from the detector array signals. Simulation results indicate that while the estimation uncertainty of both methods can be reduced substantially when the number of detected electrons is large enough. The LLS method always outperforms the SQD one regardless the detected electron numbers.

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Improvement in electron-beam lithography throughput by exploiting relaxed patterning fidelity requirements with directed self-assembly

Liu

Shen

et al. 2014

SPIE Proceedings

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New method of optimizing writing parameters in electron beam lithography systems for throughput improvement considering patterning fidelity constraints

Cited by 5 publications

References 25 publications

Lithography-patterning-fidelity-aware electron-optical system design optimization

Lithography-patterning-fidelity-aware electron-optical system design optimization

In situ beam drift detection using a two-dimensional electron-beam position monitoring system for multiple-electron-beam–direct-write lithography

Improvement in electron-beam lithography throughput by exploiting relaxed patterning fidelity requirements with directed self-assembly

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