AVS 50th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS2-WeM

Paper PS2-WeM7
Chemical Mechanisms of Metal Etching in High Density Plasmas

Wednesday, November 5, 2003, 10:20 am, Room 315

Session: Etching Difficult Materials
Presenter: A.S. Orland, Auburn University
Authors: A.S. Orland, Auburn University
R. Blumenthal, Auburn University
Correspondent: Click to Email
Metals are found at the heart of many important current and developing device technologies, such as GMR read heads, MRAM and FeRAM. As the scale of these devices continues to be reduced, high performance etch technologies will become a necessary component of the fabrication of these devices. The chemical mechanisms of high-density plasma etching of Fe, Ni, Co and their alloys will be presented for a range of etch chemistries based upon CO@sub 2@/NH@sub 3@ etching and a new etch chemistry based on CO@sub 2@/H@sub 2@ gas mixtures. The chemical mechanisms of etching have been determined from measurements of the variation of chemical composition as a function of plasma conditions, using supersonic pulse, plasma sampling mass spectrometry. Finally, the mechanism of etching will be compared with the mechanisms of CO/NH@sub 3@ and CO/H@sub 2@ etching which have been previously shown to etch by the formation of volatile metal formates and metal acetates through a plasma-surface reaction. All of these etching chemistries are plagued by carbide deposition at high concentrations of CO@sub 2@ or CO, and an explanation of the deposition mechanism will be given as well.