<title>Generation of optical disk servo patterns by lithographic imaging of photodeformable polymers</title>

A novel non-contact method of forming groove servo patterns on optical disk substrates has been demonstrated. The servo forming layer consists of a copolymer of (p-t-butyloxycarbonyloxy)styrene and styrene formulated with an onium salt which photogenerates acidic species upon exposure to deep UV radiation. If the film is heated after exposure to light the photogenerated acid cleaves the p-t-butyloxycarbonyl ("t-BOC") group resulting in a thickness change in the regions exposed to radiation. Glass substrates coated with this formulation were exposed with an appropriate mask to deep CV light and the image developed by a post exposure bake of 2 minutes at 90°C. A magneto-optic trilayer consisting of 710 A Zr0₂/800 A TbFeCo/710 A Zr0₂ was deposited onto the polymer surface. The complete structure has sufficient track error signal level to be trackable on a precision optical disk test stand with the TES servo loop closed and has a CNR of 53 dB, comparable to the same MO composition deposited on injection molded grooved polycarbonate substrates.