Abstract: A stamper for forming a data recording region on a recording medium substrate by means of a transfer surface thereof. The transfer surface transfers a predetermined set of data to the recording medium substrate. The stamper is fitted on at least one of metal molds that are arranged opposite one another for forming the recording medium substrate. The stamper includes a stepped portion formed as bends in the material of the stamper. The stepped portion is configured to project from the transfer surface toward the recording medium substrate.

Abstract: A method for manufacturing a stamper for an information medium in which a light absorbing layer containing a beam absorbing material to absorb a laser beam is formed on a glass base, a photoresist layer is formed on the light absorbing layer, the photoresist layer is irradiated with the laser beam to form a latent image, the photoresist layer is developed, and a photoresist matrix with a protrusion/depression pattern formed thereon is fabricated, stamper forming members are formed on the surface with the protrusion/depression pattern formed thereon of the photoresist matrix, the glass base of the photoresist matrix is removed, and the light absorbing layer is removed together with the photoresist layer by using strong alkaline solution. Since multiple exposure of the photoresist layer can be thus avoided, a photoresist matrix with a sharp protrusion/depression pattern and a stamper for information medium can be manufactured thereby.

Abstract: A stamper for forming a data recording region on a recording medium substrate by means of a transfer surface thereof. The transfer surface transfers a predetermined set of data to the recording medium substrate. The stamper is fitted on at least one of metal molds that are arranged opposite one another for forming the recording medium substrate. The stamper includes a stepped portion formed as bends in the material of the stamper. The stepped portion is configured to project from the transfer surface toward the recording medium substrate.

Abstract: An optical recording disk includes a support substrate, grooves and lands alternately formed on one major surface of the support substrate, an optical functioning layer formed on the one major surface of the support substrate on which the grooves and the lands are formed and including a recording layer and a light transmission layer formed on the optical functioning layer, the grooves and the lands being formed so that the depth Gd of each of the grooves is equal to or larger than 15 nm and equal to or smaller than 25 nm and the half width Gw is equal to or larger than 150 nm and is equal to or smaller than 230 nm, and the recording layer including a first recording film containing Si as a primary component and a second recording film containing Cu as a primary component.

Abstract: A resin layer including a benzophenone compound is formed on a surface of a glass substrate, and a photoresist layer is formed on a surface of the resin layer. The photoresist layer is irradiated with a laser beam with a wavelength of 100 nm to 300 nm to form a latent image, and a resist pattern with recessed and protruding parts are formed in the photoresist layer by developing the photoresist layer in which the latent image has been formed.

Abstract: A stamper for forming a data recording region on a recording medium substrate by means of a transfer surface thereof. The transfer surface transfers a predetermined set of data to the recording medium substrate. The stamper is fitted on at least one of metal molds that are arranged opposite one another for forming the recording medium substrate. The stamper includes a stepped portion formed as bends in the material of the stamper.

Abstract: A groove is present in a surface of a disc substrate. A part of the groove is curved toward another groove adjacent to the groove to thereby form a land pre-pit. The following relations hold among DG, DP and r: 0.267≦(DP/DG)2·r≦0.701; and 3.185≦(DP/DG)/r≦8.553, where DG: depth of the groove 4B, DP: depth of the land pre-pit 5A, r [&mgr;m]: distance between the center of the land pre-pit 5A and the center line of the groove 4B having the curved land pre-pit 5A.

Abstract: An optical disk master having a protrusion/depression pattern on its surface is prepared by applying a photoresist layer on a substrate, exposing the photoresist layer to radiation to form a latent image of the protrusion/depression pattern, and developing the latent image. The step of treating the photoresist layer with a surfactant is included prior to the exposing step or between the exposing and developing steps. An optical disk master having a finer pattern can be prepared at a low cost while minimizing any additional burden on the manufacturing system.

Abstract: A manufacturing method of a stamper for optical information medium comprises forming a photoresist layer on a substrate, irradiating the photoresist layer with laser beam to form a latent image thereon, developing the latent image so that a protrusion/depression pattern is formed to produce a photoresist master, and then transferring the protrusion/depression pattern to a metal film, wherein a photoresist master having an organic material layer provided in contact with the photoresist layer between the substrate and the photoresist layer is used.

Abstract: A groove is present in a surface of a disc substrate. A part of the groove is curved toward another groove adjacent to the groove to thereby form a land pre-pit.

Abstract: In an optical recording medium comprising a substrate including parallel extending lands and grooves on one surface thereof, the grooves serving as recording tracks, and the lands being formed with prepits, the height HP of the land disposed between the prepit and the groove divided by the height HL of the land in a prepit-free region, both as measured from the groove bottom, i.e., HP/HL ranges from 0.25 to less than 1. This enables to significantly increase the recording density of the medium without a substantial cost increase.

Abstract: A method for producing a photoresist master adapted for use in the manufacture of an optical information medium is provided. This method has enabled formation of a fine pattern having a minimum width which is about half of the wavelength used for the exposure, and in this method, decrease in the pattern height has been suppressed and tapering of the pattern profile has been improved. In this method comprising the steps of applying a photoresist layer on a substrate, exposing the photoresist layer to a laser beam to form a latent image in the photoresist layer, and developing the latent image to form a protrusion/depression pattern to thereby produce the photoresist master, and in this method; a light absorbing layer is formed between the substrate and the photoresist layer and in contact with the photoresist layer, and the light absorbing layer exhibits light absorption at the wavelength of said laser beam.

Abstract: A stamper for forming a data recording region on a recording medium substrate by means of a transfer surface thereof. The transfer surface transfers a predetermined set of data to the recording medium substrate. The stamper is fitted on at least one of metal molds that are arranged opposite one another for forming the recording medium substrate. The stamper includes a stepped portion formed as bends in the material of the stamper. The stepped portion is configured to project from the transfer surface toward the recording medium substrate.

Abstract: An optical disk master having a protrusion/depression pattern on its surface is prepared by applying a photoresist layer on a substrate, exposing the photoresist layer to radiation to form a latent image of the protrusion/depression pattern, and developing the latent image. The step of treating the photoresist layer with a surfactant is included prior to the exposing step or between the exposing and developing steps. An optical disk master having a finer pattern can be prepared at a low cost while minimizing any additional burden on the manufacturing system.

Abstract: In an optical recording medium comprising a substrate including parallel extending lands and grooves on one surface thereof, the grooves serving as recording tracks, and the lands being formed with prepits, the height HP of the land disposed between the prepit and the groove divided by the height HL of the land in a prepit-free region, both as measured from the groove bottom, i.e., HP/HL ranges from 0.25 to less than 1. This enables to significantly increase the recording density of the medium without a substantial cost increase.