Extremely durable CD-ROM with a novel structure

This paper describes an extremely durable CD-ROM and its reliability. A pit pattern was fabricated through a sol-gel process utilizing a 2P/epoxy work stamper. Excellent stability was guaranteed by a layered structure, such as the SiO2-ZrO2 over coat on a chemical strengthening glass substrate and the Si/SiO2-ZrO2/Cr tri- layered reflector on a sol-gel layer. Accelerated tests were implemented to estimate its lifetime. The CD-ROM lifetime at 30 degree(s)C (DOT) 90% RH was estimated to be more than 300 years. This exceedingly long lifetime was determined on the basis of the following two experimental results. Little degradation was observed in Cl error rate during about 50 days at 120 degree(s)C (DOT) 90% RH. A main degradation mode, which was observed on longer aging, was Cr film peeling-off. It was found that activation energy for Cr peeling-off process was 0.91 eV by an in-situ peeling detection tester, based on the acoustic emission method.