AVS 45th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM-WeM

Paper EM-WeM11
Studies of the Pad-Slurry-Surface Interactions in Chemical-Mechanical Polishing of Copper Thin Films and Patterned Structures

Wednesday, November 4, 1998, 11:40 am, Room 316

Session: Fundamentals of Si Cleaning and CMP
Presenter: J. Hernandez, State University of New York, Albany
Authors: J. Hernandez, State University of New York, Albany
P. Wrschka, State University of New York, Albany
G.S. Oehrlein, State University of New York, Albany
J. King, Cybeq Nano Technologies
Correspondent: Click to Email
Chemical mechanical polishing (CMP) of copper is a key technology for producing sub-micrometer Cu lines in multilevel metallization structures. In this work, blanket copper, tantalum and silicon dioxide thin films as well as copper damascene structures were polished using different pads and slurries. Selectivities of Cu/SiO@sub2@ as high as 200:1 were observed after polishing at low pressures and velocities utilizing slurries consisting of alumina abrasive particles. Examination of planarized Cu damascene microstructures by scanning electron microscopy allowed us to investigate critical issues in CMP such as SiO@sub2@ spacer erosion, copper line recess, corrosion of sub-micron copper lines, slurry contamination, and removal selectivity of the Ta diffusion barrier. Finally, surface chemical studies of Cu, Ta, and SiO@sub2@ thin films and the pad after CMP by x-ray photoelectron spectroscopy were undertaken to assist in the identification of the controlling factors of the CMP process.