AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Wednesday Sessions
       Session MI-WeA

Paper MI-WeA10
Effects of UV Illumination on Dry Etch Rates of NiFe-based Magnetic Multilayers

Wednesday, October 27, 1999, 5:00 pm, Room 618/619

Session: Giant Magnetoresistance
Presenter: H. Cho, University of Florida
Authors: H. Cho, University of Florida
K.P. Lee, University of Florida
K.B. Jung, University of Florida
S.J. Pearton, University of Florida
R.J. Shul, Sandia National Laboratories
Correspondent: Click to Email
Dry etch patterning of magnetic multilayer stacks (eg. NiFeCo/CoFe/Cu/CoFe/NiFeCo) is possible under high density plasma (HDP) conditions using chemistries such as Cl@sub 2@/Ar or CO/NH@sub 3@. The etch mechanism is ion-assisted desorption of metal chloride or metal carbonyl products. Much higher (@>=@ factor of 3) etch rates are achieved with the Cl@sub 2@-based plasma chemistries, but the rates are still limited by desorption of the FeCl@sub x@ or Cu@sub 3@Cl@sub 3@ etch products. Simultaneous UV irradiation of the sample surface during HDP Cl@sub 2@ etching has been found to convert Cu@sub 3@Cl@sub 3@ into more volatile CuCl@sub 2@ and Cu@sub 2@Cl@sub 3@ species, lowering the activation energy for desorption and enhancing the Cu etch rate.@super (1)@ We have studied the effects of UV illumination on the etch rates of NiFe and NiFeCo in Cl@sub 2@/Ar and CO/NH@sub 3@ discharges, and on the etch selectivity of these materials over a variety of different mask materials (SiO@sub 2@, photoresist, photo-definable polymers) as a function of illumination flux, process pressure and HDP source power. For prevention of post etch corrosion it is still necessary to use H@sub 2@O rinsing or in-situ H@sub 2@ or SF@sub 6@ plasma removal of chlorinated etch residues.