Methods of Determining Thin Film Stress for Optical Data Storage

Thin film stress plays an important role in the manufacture of optical data disks which have a rather low aspect ratio and are very susceptible to deformation. The stress parameter has been shown to be adjustable by varying deposition parameters. More recently, ion assisted reactive evaporation is a deposition technique which has been shown to be useful in controlling stress. The successful application of these techniques requires that that the stress be monitored in situ during the coating process, or by means of a stress monitor disk which is piggybacked in the coating run and measured afterward, or on a sample data disk from the coating run.