Real-Time Measurement and Study of Reduction Process of Copper Oxide Film by Formic Acid

Ozawa, Naoto; Okubo, Tatsuo

doi:10.5104/jiep.20.219

Cited by 5 publications

(7 citation statements)

References 5 publications

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“…The ellipsometry results of film thickness measurement correlated with the analysis of the cross-sectional TEM images of the oxide film. 31)…”

Section: Optical Model Of Ellipsometrymentioning

confidence: 99%

“…[21][22][23][24][25][26][27][28][29][30] In this study, we combined a spectroscopic ellipsometer with an originally designed vacuum chamber to study in situ the reduction of oxide films on copper plates and solder surfaces during formic acid exposure. 31,32) Furthermore, the data on the relationship between the reduction rate and copper plate temperature was obtained to determine the activation energy of the reduction of the copper oxide film by formic acid. Moreover, the reduction rate increased with increasing formic acid partial pressure.…”

Section: Introductionmentioning

confidence: 99%

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Reduction of copper oxide by formic acid in a narrow gap under various conditions

Ozawa

Maruyama

Shibata

2023

Jpn. J. Appl. Phys.

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In this study, the reduction rate of a copper oxide film by formic acid gas was measured under various conditions using a vacuum chamber and ellipsometer. The results revealed that the reduction rate of the oxide film in a narrow gap on the copper plate surface covered by a glass plate was 1.2 times greater than that on the surface of an uncovered copper plate. In addition, the reduction rate determined for a mixture of formic acid gas with a partial pressure of 1000 Pa and N2 gas with a partial pressure of 19000 Pa was approximately two times lower than that measured for pure formic acid gas supplied at a pressure of 1000 Pa. Meanwhile, increasing the partial pressure of formic acid increased the copper oxide reduction rate. Finally, the reduction rates calculated using a direct simulation Monte Carlo method were in good agreement with the experimental data.

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“…The ellipsometry results of film thickness measurement correlated with the analysis of the cross-sectional TEM images of the oxide film. 31)…”

Section: Optical Model Of Ellipsometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reduction of copper oxide by formic acid in a narrow gap under various conditions

Ozawa

Maruyama

Shibata

2023

Jpn. J. Appl. Phys.

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“…The copper oxide film formed in this study was confirmed to be Cu 2 O via TEM-EDX and TEM-EELS analyses. 41)…”

Section: Optical Model Of Ellipsometrymentioning

confidence: 99%

“…Further, field-emission transmission electron microscopy (TEM, JEM-2010F, JEOL Ltd.), TEM energy-dispersive X-ray analysis (TEM-EDX, JED-2300T, beam diameter: approximately 1.0 nm, JEOL Ltd.), and TEM-EELS (beam diameter: approximately 1.0 nm; 863 GIF Tridiem, Gatan Inc.) analyses were performed for the copper plate on which the thermal oxide film was formed. 41)…”

Section: Formation and Analysis Of Thermal Oxide Filmsmentioning

confidence: 99%

“…In situ analysis of the oxide film on a copper plate surface and a solder surface when exposed to formic acid was performed by combining a spectroscopic ellipsometer and an in-house designed vacuum chamber. 41,42) In this study, detailed data on the relationship between the reduction rate and the copper plate temperature and formic acid partial pressure were obtained by in situ spectroscopic ellipsometry analysis. In addition, the rate-determining step and the mechanism involved in the reduction reaction of the copper oxide film with formic acid were considered.…”

Section: Introductionmentioning

confidence: 99%

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Reduction process of copper oxide film by formic acid

Ozawa¹,

Shibata²

2021

Jpn. J. Appl. Phys.

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The reduction of a copper oxide surface film by formic acid was investigated in situ using a spectroscopic ellipsometer. The activation energy of the reduction of the copper oxide film by formic acid was 97.4 kJ mol−1, and the reduction rate increased with increasing formic acid partial pressure. From experimental results, we assumed that the hydrogen atoms dissociated from the formic acid molecules that were adsorbed on the copper surface and reacted with the oxygen atoms, and the oxygen atoms desorbed as water. Furthermore, it was predicted that the reduction proceeds by the diffusion of oxygen atoms from bulk copper oxide to the copper surface, and the dissociation of hydrogen atoms from the formic acid molecules was the rate-determining step. Based on this prediction, the reduction rate was mathematically calculated, which was in good agreement with the experimental data.

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Sn- and Cu-oxide reduction by formic acid and its application to power module soldering

Ozawa¹,

Okubo²,

Matsuda³

et al. 2018

2018 IEEE 30th International Symposium on Power Semiconductor Devices and ICs (ISPSD)

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Real-Time Measurement and Study of Reduction Process of Copper Oxide Film by Formic Acid

Cited by 5 publications

References 5 publications

Reduction of copper oxide by formic acid in a narrow gap under various conditions

Reduction of copper oxide by formic acid in a narrow gap under various conditions

Reduction process of copper oxide film by formic acid

Sn- and Cu-oxide reduction by formic acid and its application to power module soldering

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