Motherboard for blueray optical disc and manufacturing method for motherboard

Abstract

The invention discloses a manufacturing method for a motherboard for a blueray optical disc. The method comprises the following steps of: before a photoresist layer is formed, forming a layer of carbonized light absorption layer on a substrate; and forming the photoresist layer on the carbonized light absorption layer, so that during subsequent exposure and development, the carbonized light absorption layer can effectively reduce reflection of rays on an interface and increase light energy absorption of the lower surface of the photoresist layer, so that the light absorption rate of the rays is increased, the light sensing resolution of photoresist is enhanced, the exposure width of the bottom of the photoresist layer is increased to be close to the width of the upper surface of the photoresist layer, the gradient of a trench is increased and the density of the trench is increased to meet the precision requirement of the blueray optical disc. Furthermore, the invention also discloses the motherboard which is manufactured by the manufacturing method and used for the blueray optical disc. The motherboard can effectively increase the density of the trench of the photoresist layer after being exposed and developed so as to meet the precision requirement of the blueray optical disc.

Description

technical field [0001] The invention relates to an optical disc master disc and a manufacturing method thereof, in particular to a blue-ray optical disc master disc and a manufacturing method thereof. Background technique [0002] Blu-ray Disc (Blue-ray Disc, abbreviated as BD) is a super-large-capacity optical disc storage technology. With the continuous innovation of optical disc technology, high-density optical discs continue to emerge. A recording capacity of about 25GB (Gbytes) per layer, or a recording capacity of about 50GB with a single-sided double-layer; From a structural point of view, a single-layer Blu-ray disc has a substrate with a thickness of 1.1mm, and the master disc (master disc) is molded through an injection molding process. The pits are transferred to the surface of the substrate, and then the substrate is coated with a reflective film, and there is a cover layer on the reflective film; for the double-layer Blu-ray disc, its structure is similar to the...

AI Technical Summary

Problems solved by technology

After the exposure of the substrate prepared by this method, the etched groove shows an inverted trapezoidal shape, that is, the upper surface is wide, the bottom is narrow, and the edge slope is relatively large. The reason for this phenomenon is that the photoresist is not uniformly exposed to light on the cross section. , the upper surface receives more light, and the lower surface receives less light due to light attenuation. This cross-sectional shape is not conducive to improving the groove density, so the recording accuracy of ordinary photoresist cannot meet the requirements of Blu-ray discs.

[0005] In the case that the process cannot improve its precision, some special materials are used in its production to improve the precision. At present, the production of Blu-ray master discs mostly uses phase change materials (PTM) and dye polymers (Dye Polymer). Heat sensitive, so under the same size laser spot irradiation, exposure smaller than the spot size can be produced, but PTM materials are expensive and not easy to obtain; while Dye Polymer is heated and vaporized under laser irradiation, so the irradiated area will leave a concave structure , but because it will release gas during the photolithography process and pollute the objective lens of the laser recorder, it is necessary to gradually increase the laser intensity during the recording process, increase the complexity of the laser recorder, and also need to regularly clean the objective lens

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