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A Study on the Within Wafer Non-uniformity of Oxide Film in CMP

CMP 패드 강성에 따른 산화막 불균일성(WIWNU)에 관한 연구

  • 박기현 (부산대학교 정밀기계공학과) ;
  • 정재우 (부산대학교 정밀기계공학과) ;
  • 박범영 (부산대학교 정밀기계공학과) ;
  • 서헌덕 (부산대학교 정밀기계공학과) ;
  • 이현섭 (부산대학교 정밀기계공학과) ;
  • 정해도 (부산대학교 정밀정형 및 금형가공연구소)
  • Published : 2005.06.01

Abstract

Within wafer non-uniformity(WIWNU) improves as the stiffness of pad decrease. We designed the pad groove to study of pad stiffness on WIWNU in Chemical mechanical polishing(CMP) and measured the pad stiffness according to groove width. The groove influences effective pad stiffness although original mechanical properties of pad are unchanged by grooving. Also, it affects the flow of slurry that has an effect on the lubrication regime and polishing results. An Increase of the apparent contact area of pad by groove width results in decrease of effective pad stiffness. WIWNU and profile of removal tate improved as effective pad stiffness decreased. Because grooving the pad reduce its effective stiffness and it makes slurry distribution to be uniform. Futhermore, it ensures that pad conforms to wafer-scale flatness variability. By grooving the top pad, it is possible to reduce its stiffness and hence reduce WIWNU and edge effect.

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