"Eisboch" wrote in message
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"Calif Bill" wrote in message
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Did not know that about the Silverstone. We used sputtering for coating
the disks in disk drives.


The original disk drives were not vacuum deposited and the magnetic
orientation was horizontal, limiting the capacity of the disk. Sputtering
allowed columnar growth and the magnetic material had a vertical
orientation, a major breakthrough in terms of disk capacity.

We built several large in-line sputter deposition systems for hard disks
for Seagate and others. We also built a few CD coating systems. They
were amazing. They processed a raw CD blank in less than 2 seconds,
depositing about 600 Angstroms of aluminum (just short of becoming
opaque).

Other companies blew us away though, doing the aluminum deposition, data
imaging, protective overcoat and applying the label in less time.

Eisboch


Probably biggest improvement in disk drive capacity from the sputtering was
a much more uniform coating and less defects. Since a lot of my disk drive
design time was doing flaw scan software, I notice a lot of improvement in
that alone. Other item I notice about CD's is everybody protects the clear
side and does not worry about the coated side. But the coated side is much
more critical to data integrity.