CD Replication

A compact disc (CD) can be used to store audio, video and data in various formats, which are defined in the Rainbow Books. A CD is usually manufactured in a Class 100, a betterclean room or self-contained clean room on the finishing line - one piece of fine dust can cause a CD to fail.

CD replication is different from CD burning. In CD replication, the pits and lands of a mastered CD are moulded into the CD. A CD burner creates 'burn marks' to copy the data or recording..

Glass mastering is performed in a Class 100 clean room or self-enclosed LBR and mastering system. Contaminants such as dust, pollen, hair and smoke can leave the master inoperative if they are introduced during these critical stages of CD manufacturing. An underlying glass layer is used to hold the CD master while the glass mastering is made and processed. Glass substrates are circular plates of glass roughly 6mm thick and 240mm in diameter. They often have a small, steel hub on one side to assist managing. The glass layers are shaped specifically for CD mastering and one side is refined until it is smoother. The area on the substrate allows for better managing of the glass master and helps to resist scratching to the pit structure when the father stamper is separated from the underlying glass layer.

After the underlying glass layer cleaned with detergents and ultrasonic baths, the glass is positioned in a spin coater. This initially spins the glass and rinses it using a dissolving agent, and then applies the resist. The resist is spread across the face of the glass in a flush coating by means of rotation. The substrate is separated and cooked to dry the resist and the glass substrate is ready for mastering.

Mastering is achieved with a laser beam recorder device. There are two recording processes for CD mastering - photo-resist and non-photoresist mastering.

The Discs are then moulded. See CD Moulding. CD Replication is sometimes mistaken for CD Duplication.