Glass master (press shop)

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A metallized glass master

The glass master or the glass master is the actual pressing tool in the press shop for CD / DVD production . The process of creating a glass master is called glass mastering.

Glass mastering CD

During glass mastering for a CD, the information from the premaster is transferred to a glass pane coated with a photoresist layer with the aid of a laser beam, similar to when burning a CD-R . Their diameter is 240 mm and the thickness 6 mm. It may also have a metal inner circle to enable industrial processing. The carriers are specially created for glass mastering and the carrier surface must be polished to be absolutely smooth, because even microscopic scratches on the glass carrier influence the quality of the created glass master.

The resulting glass master serves as a template for creating the stamper during electroplating . However, the light-sensitive lacquer layer is irretrievably destroyed at the beginning of the electroplating process, so that only the factory-specific stampers created from it can be stored and used for subsequent pressings.

Glass mastering must be carried out in a clean room that meets at least the requirements of class 100 (= ISO 5). Dust, pollen, hair, or particles of smoke can destroy the created glass master while it is being created. When the glass master is finished, it can no longer be influenced by these environmental influences; but this can render it unusable during manufacture.

Glass mastering DVD

Basically, the process is very similar to glass mastering for CD production. However, separate stampers must be created for each layer that contains data .

Individual evidence

  1. a b ADR AG ( Memento from January 27, 2016 in the Internet Archive )

See also