CD Replication or Compact Disc manufacturing is when CD's
are reproduced in large numbers by means of a master version
created from a source recording. They may be replicated in audio
fomat (CD-Audio), or data format (CD-ROM). This process is used
in the mastering of CD's and does not include CD-Rs or DVD's,
although these are replicated using similar methods.
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
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.