The effects of polymer side-chain structure on roughness formation of ArF photoresist in plasma etching processes

Uesugi, Takuji; Okada, Takeru; Wada, Akira; Kato, Keisuke; Yasuda, Atsushi; Maeda, Satoshi; Samukawa, Seiji

doi:10.1088/0022-3727/45/7/075203

Cited by 7 publications

(5 citation statements)

References 24 publications

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“…Capacitive radio frequency (rf ) plasmas have been widely utilized for many industrial applications, such as plasma simulations and experiments to reveal new rf plasma physics, with the focus on the fundamental principles for the control and prediction of plasma behaviors under different discharge conditions [13][14][15][16][17]. Capacitive rf plasmas have been extensively utilized in plasma etching processes for semiconductor microchip fabrication [18][19][20][21]. However, nowadays, the design of rf plasmas is increasingly diversified due to the increased application requirements.…”

Section: Introductionmentioning

confidence: 99%

Similarity properties in capacitive radio frequency plasmas with nonlinear collision processes

Yang

Zheng

et al. 2021

Plasma Sources Sci. Technol.

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Similarity laws (SL) are essential for correlating the characteristics of plasmas at different dimensional scales, which have been validated for radio frequency (rf) discharges at low pressure but under limited conditions. In this work, we evaluate the effects of nonlinear collisions (e.g. stepwise ionization) on the similarity properties in capacitive rf discharges in argon across a wide range of pressure regimes via fully kinetic particle-in-cell simulations. The SL scalings of fundamental discharge parameters, e.g. the electron power absorption and electron energy probability function, are examined with and without nonlinear collisions, respectively. Without the nonlinear collisions, the similarity scalings are found to be rigorously valid. When the nonlinear collisions are considered, the similarity properties in rf discharges still exist approximately, which indicates that the violations caused by the nonlinear collisions are still minor in the studied cases. The reasons for the effectiveness of SL scalings with nonlinear collision processes are also discussed. The results from this study confirmed the validity of similarity transformations with more complex reaction kinetics, which may promote the applicability of the SL scalings for the design and fabrications of plasma devices.

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Section: Introductionmentioning

confidence: 99%

Similarity properties in capacitive radio frequency plasmas with nonlinear collision processes

Yang

Zheng

et al. 2021

Plasma Sources Sci. Technol.

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“…The elemental ratio of oxygen atoms and the amount of ring structure are key factors in the etching resistance. [9] Moreover, on the basis of our results, we proposed a novel photoresist polymer. By adding polar structures such as cyano or hydroxyl, chemical reactions between reactive species and photoresist were spread evenly, resulting in the suppression of surface roughness by decreasing the selective etching.…”

Section: Introductionmentioning

confidence: 94%

“…According to previous reports, the etching rate of photoresist polymer was mainly determined by the amount of ring structures. [9,[12][13][14] DAdMA, CMAMA, and CNNMA have the ring structure "Norbornane" at the lactone group monomer unit. Therefore, these three photoresists had higher etching resistance than α-GBLMA.…”

Section: Surface Analysismentioning

confidence: 99%

Novel ArF photoresist polymer to suppress the roughness formation in plasma etching processes

et al. 2013

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The serious problem associated with 193-nm lithography using an ArF photoresist is roughness formation of photoresist polymer during plasma processes. We have previously investigated the mechanism of roughness formation caused by plasma. The main deciding factor for roughness formation is a chemical reaction between photoresist polymer and reactive species from plasma. The lactone group in photoresist polymer is highly chemically reactive, and shrinking the lactone structure enhances the roughness formation. In this paper, on the basis of the mechanism of roughness formation, we propose a novel ArF photoresist polymer. The roughness formation was much more suppressed in the novel photoresist polymer during plasma etching process than in the previous type. In the novel photoresist polymer, chemical reactions were spread evenly on the photoresist film surface by adding the polar structure. As a result, decreases in the lactone group were inhibited, leading to suppressing ArF photoresist roughness.

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“…Low-pressure radio-frequency (rf ) discharge plasmas play significant roles in applications in the semiconductor manufacturing field, such as plasma etching, which has attracted extensive attention in recent decades [1][2][3]. In particular, rf plasma sources are indispensable for semiconductor fabrication, such as high-aspect-ratio trench etching and enhanced deposition [4][5][6]. Previously, experimental and numerical studies have been extensively conducted to determine the rf discharge characteristics, such as the electron kinetics and the control parameter scaling features [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Application of similarity laws to dual-frequency capacitively coupled radio frequency plasmas with the electrical asymmetry effect

Yang¹,

Wang²,

Zheng³

et al. 2022

Plasma Sources Sci. Technol.

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Similarity laws (SLs) are useful for correlation and prediction of plasma parameters at different scales, which have been verified for geometrically symmetric capacitive radio-frequency (rf) discharges in nonlocal kinetic regimes. In this work, we demonstrate the applicability of SLs to dual-frequency rf discharges and confirm that similarity relations still hold considering the electrical asymmetry effect (EAE). By simultaneously tuning the control parameters (the gas pressure p, discharge gap d, and driving frequency f), we examine the similarity relations in rf plasmas via fully kinetic particle-in-cell simulations with the external circuits coupled and solved self-consistently. The validity of the SL scalings in dual-frequency rf plasmas with the EAE is confirmed for parameters such as the electron/ion density, ion flux, dc self-bias, ion energy distribution function, and power absorption. Although adjusted by the EAE, the dc self-bias and ion energy distribution functions are identified as similarity invariants under similar discharge conditions. Furthermore, the plasma series resonance phenomenon, filamentation of power depositions of electrons and ions in bulk plasma, and electric field reversal are observed in dual-frequency discharges with the EAE, which can also be exactly replicated under similar discharge conditions. The results further extend the application of SL scaling to dual-frequency rf plasmas, providing a more comprehensive understanding of the scaling characteristics in rf plasmas.

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The effects of polymer side-chain structure on roughness formation of ArF photoresist in plasma etching processes

Cited by 7 publications

References 24 publications

Similarity properties in capacitive radio frequency plasmas with nonlinear collision processes

Similarity properties in capacitive radio frequency plasmas with nonlinear collision processes

Novel ArF photoresist polymer to suppress the roughness formation in plasma etching processes

Application of similarity laws to dual-frequency capacitively coupled radio frequency plasmas with the electrical asymmetry effect

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