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

Abstract

We investigated industrial deposition processes for spin-valve giant magneto resistance (GMR) multilayers. We compared rf diode with dc 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 dc 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, dc magnetron deposition allows accurate control of the deposition time, and thus the thickness of 10–100 Å films. Applying this method to spin-valve deposition results in a controllability of 0.5 Å, a uniformity around 1% (=1σ) over 150 mm wafers and repeatability around 1%. This implies that this process meets the requirements for production of GMR magnetic read heads.