title: Characterization of wet pad surface in chemical mechanical polishing (CMP) process with full-field optical coherence tomography (FF-OCT).
abstract: Chemical mechanical polishing (CMP) is a key process for global planarization of silicon wafers for semiconductors and AlTiC wafers for magnetic heads. Removal rate of wafer material is directly dependent on the surface roughness of a CMP pad, thus the structure of the pad surface has been evaluated with variable techniques. However, under in situ CMP process, the measurements have been severely limited due to the existence of polishing fluids including the slurry on the pad surface. In here, we newly introduce ultra-high resolution full-field optical coherence tomography (FF-OCT) to investigate the surface of wet pads. With FF-OCT, the wet pad surface could be quantitatively characterized in terms of the polishing pad lifetime, and also be three-dimensionally visualized. We found that reasonable polishing span could be evaluated from the surface roughness measurement and the groove depth measurement made by FF-OCT.
authors: School of Information and Communications, Gwangju Institute of Science and Technology, Buk-Gu, Gwangju, South Korea.
authors: Woo June
authors: WJ
authors: Choi
authors: Sung Pyo
authors: SP
authors: Jung
authors: Jun Geun
authors: JG
authors: Shin
authors: Danning
authors: D
authors: Yang
authors: Byeong Ha
authors: BH
authors: Lee
mesh_terms: D008420:Manufactured Materials / Q000032:analysis*; D008669:Metallurgy / Q000379:methods*; D008846:Micromanipulation / Q000379:methods*; D012825:Silicon / Q000737:chemistry*; D041623:Tomography, Optical Coherence / Q000379:methods*; D017155:Wettability
chemical_list: D012825:Silicon