A new simple method was developed to make a groove on an optical memory disc. This uses the swelling of the Te-C material. A bulged line is formed by irradiating laser light onto the Te-C layer which has a thin metal layer over it. This dry process is called the Ω(OMEGA)-process from the sectional shape of the groove. The Ω-disc should have a lower error rate and a higher track density than the disc made through a conventional wet process.