Experimental determination of stress in magnetic recording thin film disks

An experimental program is described to help understand and explain the stress state in Cr and CoCrPt thin films sputtered on ceramic (canasite) substrates. Thin film magnetic recording disk substrates are used with production process equipment. A measurement technique is developed. The effect of Cr thickness and sputter preheat on stress in the Cr layer is determined. Stresses in equal thickness Cr and CoCrPt films on canasite are compared. Repeatability of stress levels in films deposited several weeks apart is examined. Average stress immediately after deposition and after several weeks is determined to look for time-dependent effects. A factorial experiment explores the process space of preheat, Cr thickness, and CoCrPt thickness with average film stress as the output variable. After making several assumptions, stress in the CoCrPt layer is computed from the data, leading to a determination of average CoCrPt stress in the process space. The stress state in the Cr layer is controlled by a reduction in argon sputter pressure to introduce atomic shot peening. An outline for further experimental work is developed