Meeting the process challenges for spin-valve fabrication on an industrial scale

We investigated industrial deposition processes for spin-valve giant magneto resistance (GMR) multilayers. We compared rf diode with magnetron deposited films, as well as films deposited in a cluster tool equipped with single target process modules and a multitarget module. It is found that the best MR response is obtained by using de magnetron deposition in a multitarget process module, as this minimizes contamination by background gas atoms and interface mixing due to self-biasing of the substrate. Furthermore, de magnetron deposition allows accurate control of the deposition lime, and thus the thickness of 10-100 Angstrom films. Applying this method to spin-valve deposition results in a controllability of 0.5 Angstrom, a uniformity around 1% (= 1 sigma) over 150 mm wafers and repeatability around 1%. This implies that this process meets the requirements for production of GMR magnetic read heads. (C) 1998 American Vacuum Society. [S0734-2101(98)01604-2].