Modeling and measurement of hydrogen radical densities of <i>in situ</i> plasma-based Sn cleaning source

Elg, Daniel T.; Panici, Gianluca A.; Peck, J.; Srivastava, Shailendra N.; Ruzic, D. N.

doi:10.1117/1.jmm.16.2.023501

Cited by 7 publications

(4 citation statements)

References 25 publications

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“…These values and trends are in good agreement with previous studies. [ 45–47 ] As the electron density increases from 10 9 to 3.5 × 10 10 cm −3 at a pressure of 20 mTorr, the H density increases, and the H 2 density tends to decrease as shown in Figure 6b. This is because the electron temperature is constant, and under fixed electron temperature and gas pressure conditions, the reaction rate is proportional to the electron density.…”

Section: Resultsmentioning

confidence: 94%

Evaluation of H₂ Plasma‐Induced Damage in Materials for EUV Lithography

Choe,

Choi,

Kim

et al. 2023

Adv Materials Inter

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Ultrafine semiconductor fabrication by lithography has undergone a significant transition from deep ultraviolet (DUV) to extreme ultraviolet (EUV) processes, which presents new challenges. Specifically, the damage caused to components utilized in an EUV system, such as multilayer mirrors, reticles, and pellicles within lithography equipment, owing to EUV‐induced H2 plasma, is a critical issue that directly affects the process yield and equipment lifespan. To address these issues, it is crucial to establish an environment similar to that of EUV‐induced plasma and develop a method to evaluate the resulting damage. Accordingly, an evaluation method is developed for assessing the material damage caused by hydrogen radicals and ions in inductively coupled H2 plasma. In these systems, the electron density ranged from 5 × 108 to 3.5 × 1010 cm−3, the electron temperature ranged from 1 to 4 eV, and the ion energy ranged from several to tens of eV; these conditions closely align with the environment of an EUV‐induced H2 plasma. The damage to Mo2C, a potential EUV pellicle material, is quantitatively analyzed by measuring the fraction of the pore area and examining the chemical characteristics after exposing the samples to various plasma conditions, including electron density, gas pressure, and exposure time.

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Section: Resultsmentioning

confidence: 94%

Evaluation of H₂ Plasma‐Induced Damage in Materials for EUV Lithography

Choe,

Choi,

Kim

et al. 2023

Adv Materials Inter

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“…As shown in figure 3(a), when the ratio of H 2 /Cl 2 in the adsorption gas mixture was 1/5 or 0/1, therefore, when the gas mixture was a highly chlorine rich gas, no etching of Sn was observed up to 100 s of adsorption time. However, as the ratio of H 2 is increased in the H 2 /Cl 2 adsorption gas mixture, the increase of EPC with the increase of adsorption time was observed indicating spontaneous etching of Sn during the adsorption step (it has already been reported that Sn reacts with H radical and is etched spontaneously in H and H-rich gas environments [10,23,24]). The EPCs for the H 2 /Cl 2 gas ratios of 3/1 and 5/1 were slightly higher than that for H 2 only.…”

Section: Resultsmentioning

confidence: 98%

Atomic layer etching of Sn by surface modification with H and Cl radicals

Kim¹,

Jang²,

Kim³

et al. 2022

Nanotechnology

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Sn is the one of the materials that can be used for next generation extreme ultraviolet (EUV) mask material having a high absorption coefficient and, for the fabrication of the next generation EUV mask, a precise etching of Sn is required. In this study, the atomic layer etching (ALE) process was performed for the precise etch thickness control and low damage etching of Sn by the formation SnHxCly compounds on the Sn surface using with H and Cl radicals during the adsorption step and by the removal of the compound using Ar+ ions with a controlled energy during the desorption step. Through this process, optimized ALE conditions with different H/Cl radical combinations that can etch Sn at ~2.6 Å/cycle were identified with a high etch selectivity over Ru which can be used as the capping layer of the EUV mask. In addition, it was confirmed that not only the Sn but also Ru showed almost no physical and chemical damage during the Sn ALE process.

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“…The pressure was set to 50 Pa, and the average and at 1-20 W were substituted into the initial values of the equation. According to the literature, the recombination coefficient of hydrogen atoms on the surface of stainless steel is 0.07 [19,20], and the recombination coefficient of hydrogen ions is 0.9 [21]. The plasma is electrically neutral by default.…”

Section: Diagnosis Of Plasma Parametersmentioning

confidence: 99%

Investigation of an electrode-driven hydrogen plasma method for in situ cleaning of tin-based contamination

PENG 彭,

YE 叶,

WANG 王

et al. 2024

Plasma Sci. Technol.

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To prolong the service life of the optics, the feasibility of in situ cleaning of multilayer mirror (MLM) of tin and its oxidized contamination was investigated using hydrogen plasma at different powers. Granular tin-based contamination consisting of micro and macro particles was deposited on the silicon by physical vapor deposition (PVD). The electrode-driven hydrogen plasma at different powers was systematically diagnosed using the Langmuir probe and the retarding field ion energy analyzer (RFEA). Moreover, the magnitude of the self-biasing voltage was measured at different powers, and the peak ion energy was corrected for the difference between the RFEA measurements and the self-biasing voltage (ΕRFEA-eVself). XPS analysis of O 1s, Sn 3d peaks demonstrated the chemical reduction process after 1 W cleaning. Analysis of surface and cross-section morphology revealed the holes emerged on the upper part of the macroparticles while its bottom remained smooth. Hills and folds appeared on the upper part of the microparticles, confirming the top-down cleaning mode with hydrogen plasma. This study provides in situ electrode-driven hydrogen plasma etching process of tin-based contamination and is of meaningful guidance for understanding the chemical mechanism of reduction and etching.

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Modeling and measurement of hydrogen radical densities of in situ plasma-based Sn cleaning source

Cited by 7 publications

References 25 publications

Evaluation of H₂ Plasma‐Induced Damage in Materials for EUV Lithography

Evaluation of H₂ Plasma‐Induced Damage in Materials for EUV Lithography

Atomic layer etching of Sn by surface modification with H and Cl radicals

Investigation of an electrode-driven hydrogen plasma method for in situ cleaning of tin-based contamination

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Modeling and measurement of hydrogen radical densities of in situ plasma-based Sn cleaning source

Cited by 7 publications

References 25 publications

Evaluation of H2 Plasma‐Induced Damage in Materials for EUV Lithography

Evaluation of H2 Plasma‐Induced Damage in Materials for EUV Lithography

Atomic layer etching of Sn by surface modification with H and Cl radicals

Investigation of an electrode-driven hydrogen plasma method for in situ cleaning of tin-based contamination

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Evaluation of H₂ Plasma‐Induced Damage in Materials for EUV Lithography

Evaluation of H₂ Plasma‐Induced Damage in Materials for EUV Lithography