Diamond Conditioner Microwear Effect on Pad Surface Height Distribution in Tungsten Chemical Mechanical Polishing

In this study, the surface topographies of chemical mechanical polishing (CMP) pad samples for varying levels of diamond microwear of a conditioner have been measured using a confocal microscope and an X-ray computer tomography (CT) scanner. The experimental results showed that the increase in the p...

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Bibliographic Details
Published inJapanese Journal of Applied Physics Vol. 50; no. 5; pp. 05EC05 - 05EC05-6
Main Authors Yamada, Yohei, Kawakubo, Masanori, Kadomura, Kazunori
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.05.2011
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Summary:In this study, the surface topographies of chemical mechanical polishing (CMP) pad samples for varying levels of diamond microwear of a conditioner have been measured using a confocal microscope and an X-ray computer tomography (CT) scanner. The experimental results showed that the increase in the pad debris on the pad surface reduced the pad height ratio of the asperity called the "top surface area (TSA) ratio". In addition, the overall removal rate in tungsten CMP was more dependent on the TSA ratio after polishing than on that after conditioning because the pad surface condition became worse with deformed asperities and micropores due to the insufficient conditioning.
Bibliography:Confocal microscopic images of diamond abrasives. Layout of diamond abrasives. Cross-sectional X-ray CT images of (a) brand-new pad and (b) pad after conditioning. X-ray CT images of pad after conditioning from top surface of pad. TSA ratio measurement procedure: (a) pad height profile, (b) confocal image of pad surface, (c) binarized image of pad surface, and (d) pad height histogram. SEM images of diamond abrasives (a) before and (b) after mechanical wear test. Normalized pad wear rate dependence on worn area. TSA ratios after pad conditioning as a function of distance from top surface of pad. TSA ratio at 20 μm from top surface, dependent on worn area. SEM images of pad after conditioning with worn disk. Schematic cross sections of pads and SEM images of pad surface: (a) worn area 0%, (b) worn area 50%, and (c) worn area 100%. Normalized pad wear rate dependence on pad conditioning COF. TSA ratio after CMP and normalized removal rate as a function of worn area. X-ray CT images of pad surface after CMP (a) with reference disk and (b) with mechanically worn disk.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.50.05EC05