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CD & DVD Electroforming
Electroforming is needed to make stampers for
replication from the glass masters. |
Once the glass masters have been developed and metallised, the next step
is to make stampers via a process of making fathers, mothers then stampers.
 Nickel fathers, mothers and stampers are created from the
metallised glass master by electroforming in a class 1000 clean room environment.
The
father is electroformed from the metallised
glass master (see diagram) and then the surface containing the 'bumps' is oxidised ready
for the next stage. (This allows the mother to be separated from the father).
The mother is then electroformed from the father and
is an essential intermediate stage from which the stamper(s) are then
electroformed in a similar way.
After the mother has been created, the father can then be
used as a stamper. Only mothers are needed for creating subsequent
stampers. Additional stampers are created for long runs.
The photoresist on the glass master is then removed and the
glass cleaned ready to be used again.
Stamper
Finishing
Each
stamper is checked visually, the back polished, it is punched to the required outside
diameter, a hole accurately punched in the centre and finally it is checked on a stamper
player before being fitted to the press.
Stamper finishing is an important stage as it will affect
the quality of the final disc. The centre hole must be accurately cut to avoid
eccentricity which could affect the playability of CD-ROMs or DVD-ROMs using modern high speed
drives. Also the stamper thickness must be uniform to avoid unbalance problems in
the finished discs.
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