Improvement of oxide removal rate in chemical mechanical polishing by forming oxygen vacancy in ceria abrasives via ultraviolet irradiation

Kim, Eungchul; Hong, Jiah; Hong, Seok‐Jun; Kanade, Chaitanya; Seok, Hyunho; Kim, Hyeong‐U; Kim, Taesung

doi:10.1016/j.matchemphys.2021.124967

Cited by 33 publications

(11 citation statements)

References 28 publications

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“…It was fixed at a distance of 3.5 cm apart from the surface when 500 mL of the slurry was placed in the beaker. The wavelength of the light generated by the UV-light source was 254 nm at 6 W, and the intensity of UV light on the surface of the solution was 489 mW/cm 2 25 . Since the light of wavelength lower than 254 nm can provide photon energy greater than that of the bandgap of the ceria particles (3–3.6 eV 79 ), the separation of the electron-hole pair from the valance band of ceria decreases the oxygen vacancy formation energy from 1.16 eV to -0.64 eV in the presence of UV light 25 .…”

Section: Methodsmentioning

confidence: 99%

“…The wavelength of the light generated by the UV-light source was 254 nm at 6 W, and the intensity of UV light on the surface of the solution was 489 mW/cm 2 25 . Since the light of wavelength lower than 254 nm can provide photon energy greater than that of the bandgap of the ceria particles (3–3.6 eV 79 ), the separation of the electron-hole pair from the valance band of ceria decreases the oxygen vacancy formation energy from 1.16 eV to -0.64 eV in the presence of UV light 25 . With the lowered oxygen vacancy formation energy, the electrons and holes generated from the UV irradiation reduce Ce 4+ to Ce 3+ and the holes oxidize O 2− anions 24 , 29 .…”

Section: Methodsmentioning

confidence: 99%

“…Several studies have shown that doping metal ions into CeO 2 lattice results in superior catalytic performance by lowering the oxygen vacancy formation energy required to detach an oxygen atom from the surface 23 , 24 . Previously, we demonstrated that UV light irradiation can generate a large number of oxygen vacancy defects and increase the Ce 3+ concentration, leading to an effective reduction of ceria 25 . It is known that ambient oxygen level promotes a reoxidation process of ceria, in other words, inhibits the reduction reaction of ceria 26 .…”

Section: Introductionmentioning

confidence: 98%

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Photo-oxidative degradation of polyacids derived ceria nanoparticle modulation for chemical mechanical polishing

Kim

Hong

Seok

et al. 2022

Sci Rep

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The effects of photo-oxidative degradation of polyacids at various concentrations and with different durations of ultraviolet (UV) irradiation on the photo-reduction of ceria nanoparticles were investigated. The effect of UV-treated ceria on the performance of chemical mechanical polishing (CMP) for the dielectric layer was also evaluated. When the polyacids were exposed to UV light, they underwent photo-oxidation with consumption of the dissolved oxygen in slurry. UV-treated ceria particles formed oxygen vacancies by absorbing photon energy, resulting in increased Ce3+ ions concentration on the surface, and when the oxygen level of the solution was lowered by the photo-oxidation of polymers, the formation of Ce3+ ions was promoted from 14.2 to 36.5%. Furthermore, chain scissions of polymers occurred during the oxidation process, and polyacids with lower molecular weights were found to be effective in ceria particle dispersion in terms of the decrease in the mean diameter and size distribution maintaining under 0.1 of polydispersity index. With increasing polyacid concentration and UV irradiation time, the Ce3+ concentration and the dispersity of ceria both increased due to the photo-oxidative degradation of the polymer; this enhanced the CMP performance in terms of 87% improved material removal rate and 48% lowered wafer surface roughness.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Photo-oxidative degradation of polyacids derived ceria nanoparticle modulation for chemical mechanical polishing

Kim

Hong

Seok

et al. 2022

Sci Rep

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“…Ultraviolet irradiation has also been applied to form O vacancies in layered materials. 105 Several researchers have observed that UV light irradiation produce O vacancies in BiOCl. [106][107][108] Due to low bond energy as well as long bond length between Bi and O in BiOCl, the Bi-O bond is easily broken by highpowered UV irradiation, leaving O vacancies.…”

Section: Ultraviolet Irradiationmentioning

confidence: 99%

Vacancy designed 2D materials for electrodes in energy storage devices

Kumar¹,

Sahoo²,

Joanni³

et al. 2023

Chem. Commun.

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“…The representative strategies reported to increase the Ce 3+ ratio in ceria NPs are abrasive doping with lanthanide elements, 25,26 synthesizing small aggregated particles, 27 forming core-shell structures [28][29][30] and irradiating ultraviolet (UV) light. 31 However, synthesizing a core-shell structure beyond a simple particle structure is complicated and inefficient in some cases. Also doping lanthanide elements or UV irradiation approaches have a limitation in terms of reacting homogeneously on the surface of particles.…”

Section: Introductionmentioning

confidence: 99%