RESOLUTION LIMIT OF OPTICAL DISC MASTERING

With the increase of the information density on optical discs, it beco mes increasingly necessary to improve the quality and the resolution o f the optical disc mastering process. The obvious approach is to reduc e the size of recorded structures by reducing the lambda/NA ratio oi t he recorder. Indeed, mastering at UV wavelengths has been put into pra ctice by several companies. This paper deals with an additional route towards higher resolution. It is shown that the combination of improve d photoresist processes and better exposure techniques can lead to a c lear reduction of the smallest achievable pit size. Combining such tec hniques with UV mastering, pit lengths below 200 nm should be well wit hin reach of classical optical disc mastering.