Study on possible root causes of contamination from an incoming PVA brush during post-CMP cleaning

Lee, Jung-Hwan; Purushothaman, M.; Han, Kwang-Min; Ryu, Hoon; Yerriboina, Nagendra Prasad; Kim, Tae-Gon; Wada, Yutaka; Hamada, Shigeru; Hiyama, Hirokuni; Park, Jin-Goo

doi:10.1016/j.polymertesting.2019.105921

Cited by 15 publications

(7 citation statements)

References 17 publications

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“…In addition, these nanoparticles can cause serious damage to the wafer and PVA brush during cleaning. To solve these issues, optimal process parameters and brush cleaning methods have been investigated. ,− However, a detailed understanding of a nanoparticle–PVA interaction has remained elusive. In particular, the influence of hydration on nanoparticle adhesion to a PVA brush has hardly been investigated.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Silica Nanoparticle Adhesion to Poly(vinyl alcohol) Surfaces by Ammonia-Mediated Hydration: Implications for Effective Post-Chemical–Mechanical Planarization Cleaning

Ikarashi

Yoshino

Nakajima

et al. 2020

ACS Appl. Nano Mater.

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Adhesion of silica abrasive nanoparticles to a poly(vinyl alcohol) (PVA) brush surface in a post-CMP (chemical mechanical planarization) cleaning leads to serious 1 problems in yield enhancement of semiconductor fabrication. However, the nanoscale adhesion mechanism and its correlation with process conditions have hardly been understood. In this study, we investigated the influence of ammonia in the cleaning solution on silica nanoparticle adhesion to a PVA surface. By atomic force microscopy (AFM), we directly measured adhesion forces between a nanoscale silica probe and a PVA brush surface in various solutions and found that ammonia has a significant inhibitory effect against silica nanoparticle adhesion to a PVA surface. Importantly, we found that this effect cannot be explained by the electrostatic interactions alone, but also involves steric repulsion between silica and hydrated PVA. We also performed molecular-scale three-dimensional scanning force microscopy (3D-SFM) imaging and contact angle measurements, and found that ammonia promotes hydration and swelling of PVA. Furthermore, we performed molecular dynamics simulations and found that ammonia promotes dynamic rearrangements of hydrogen bonding networks (HBNs) at a PVA-water interface, giving extra flexibility to the PVA chains. Such flexibility promotes local swelling of PVA and inhibits silica nanoparticle adhesion to a PVA surface. This provides important guidelines for optimizing nanoscale structures and interactions of brush surfaces and abrasive nanoparticles in post-CMP cleaning.

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Section: Introductionmentioning

confidence: 99%

Inhibition of Silica Nanoparticle Adhesion to Poly(vinyl alcohol) Surfaces by Ammonia-Mediated Hydration: Implications for Effective Post-Chemical–Mechanical Planarization Cleaning

Ikarashi

Yoshino

Nakajima

et al. 2020

ACS Appl. Nano Mater.

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“…Ultrasonication provides sonication energy by acoustic streaming and cavitation that can facilitate the efficient removal of abrasives. 7,[36][37][38][39][40] Conditioning was performed by ultrasonication of the contaminated nodules in DIW and NH 4 OH (2 wt.%), as shown in Fig. 10.…”

Section: Resultsmentioning

confidence: 99%

Study on PVA Brush Loading and Conditioning during Shallow Trench Isolation Post-CMP Cleaning Process

Sahir

Cho

Kim

et al. 2022

ECS J. Solid State Sci. Technol.

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Polyvinyl acetal (PVA) brush cleaning is a widely accepted and efficient process for removing contaminants of the chemical mechanical planarization process during semiconductor processing. However, contaminants can adhere to the PVA brush, due to its highly hydrophilic and porous nature, and deteriorates its performance. This contamination is a serious problem, especially for processing devices smaller than 10 nm. Here, the effect of cleaning solution pH was investigated for ceria removal from oxide wafers and subsequent transfer to the PVA brush during scrubbing. A cleaning solution of pH 7 resulted in lower ceria removal efficiency compared to pH 2 and 12. The pH 2 and 7 cleaning conditions resulted in high brush loading compared to the pH 12 condition. High brush contamination at pH 7 resulted in higher cross contamination, whereas very low cross-contamination was observed at pH 2 and 12. The effect of ultrasonication and scrubbing on improvement of brush performance and lifetime was evaluated. Scrubbing in the presence of NH4OH efficiently removed all ceria particles from contaminated brushes. Because the bonding between brush and ceria particles is strong, only a robust physical force combined with a high chemical action can remove ceria particles loaded onto a PVA brush.

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“…57 • PVA brushes at times, act as a source of contaminant by releasing organic components such as PDMS (Polydimethylsiloxane) and SDS (Sodium dodecyl sulfate) onto the wafer and thereby causing organic defects during post-CMP cleaning. 62 It is to be noted that unlike pencil-type PVA brush (another type of PVA brush), a higher content of the mentioned impurities are observed in roller brushes due to the formation of skin layer during the brush molding process. 63 This is because of the increase in contact area that comes with the dense skin layer.…”

Section: Post-cmp Cleaning Process and Equipmentmentioning

confidence: 99%

Review—Post-Chemical Mechanical Planarization Cleaning Technology

Hazarika,

Gupta,

Rajaraman

2023

ECS J. Solid State Sci. Technol.

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Chemical mechanical planarization (CMP), a commonly employed process for attaining local and global planarization in integrated circuits fabrication, leaves contaminants and defects on the surface polished. Due to the miniaturization of devices, new materials/ processes for the fabrication of IC circuits are considered, introducing new post-CMP issues. As such, understanding of post-CMP cleaning process is critical to choose an appropriate method for the given material. Here, the types of contaminants and defects generated during the post-CMP process and the issues related to it are discussed. The different physical and chemical cleaning methods employed in the post-CMP cleaning process to eradicate these defects are elucidated.In particular, the PVA brushing method, which is currently preferred, is elaborated upon in detail. The various chemistries, including the newly suggested ones in recent years for cleaning different substrates, are summarized. The post-CMP cleaning methods for various materials such as Cu, Al, W, Co, Ru, InGaAs, Ge, and SiO2 are mainly addressed here. This review also provides the direction of progress for the post-CMP cleaning process in terms of evolution of new techniques and chemistries for the next generation of materials.

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Study on possible root causes of contamination from an incoming PVA brush during post-CMP cleaning

Cited by 15 publications

References 17 publications

Inhibition of Silica Nanoparticle Adhesion to Poly(vinyl alcohol) Surfaces by Ammonia-Mediated Hydration: Implications for Effective Post-Chemical–Mechanical Planarization Cleaning

Inhibition of Silica Nanoparticle Adhesion to Poly(vinyl alcohol) Surfaces by Ammonia-Mediated Hydration: Implications for Effective Post-Chemical–Mechanical Planarization Cleaning

Study on PVA Brush Loading and Conditioning during Shallow Trench Isolation Post-CMP Cleaning Process

Review—Post-Chemical Mechanical Planarization Cleaning Technology

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