Manufacturing of CDs and DVDs
Christie Nickson
Introduction
z Compact Discs
y Digital technology
y Excellent sound quality
y 650 MB storage
z DVD
y Excellent sound and video quality
y More storage, 4.7-17 GB
z
Manufacturing Process
z
z
z
z
z
Premastering
Mastering
Plating/Electroforming
Injection Molding
Metallization/Spin
Coating
z Lacquering
z Screen
Printing/Packaging
Premastering
z Information inspected and prepared for CD or
DVD.
z Audio premastering
y PQ Encoding
y Digital Audio Editing
z DVD premastering
y Authoring
Mastering
z Transfer data onto glass
master by laser beam.
z Laser creates pits on a film
on the glass.
z 2 techniques
y Photo Resist
y Dye-Polymer
Photo Resist
z Thin layer (0.12
micrometer) of photo
resist spin coated on
highly polished glass
surface.
z Laser beam recorder
exposes areas on the
photo resist layer.
Photo Resist
z Photo resist chemically developed to create
pits in exposed areas.
z Developed photo resist vacuum coated with
thin layer of nickel or nickel alloy.
Dye-Polymer Process
z Dry process - no chemical developing.
z Dye material used on glass that vaporizes
when heat of recording laser is absorbed
creating the pits.
z Advantage is another laser can check pit size
and depth during recording and errors found
immediately.
Plating/Electroforming
z Negative copy of master is
made out of metal.
z Glass master placed in tank
of nickel plating solution.
z 0.3-0.4 mm thick layer of
metal forms on master.
z
Plating/Electroforming
z Metal and master are separated creating
negative copy (father).
z Father is then used to create metal copy of
master (mother) by same method.
z Mother is then used to create many metal
stampers.
z Each stamper can be used to produce several
thousand discs.
Injection Molding
z Stamper is installed in plastic
injection molding machine.
z Polycarbonate resin is injected
into mold under pressure.
z Resin cools, solidifies and is
removed from mold.
Metallization/Spin Coating
z Discs are transparent after molding.
z A thin layer of aluminum is applied by
vacuum deposition.
z Metallization is necessary to get a mirror
surface which will reflect laser light and read
pits.
Lacquering
z A layer of lacquer is applied by
spin coating.
z Lacquer protects aluminum
from oxidizing, which would
make the disk unreadable.
z Lacquer is cured by ultra-violet
light.
Screen Printing &
Packaging
z Upper surface can be printed
with up to 5 colors.
z Flat silk screen process used
and ink is cured with UV
light.
z Disks are packaged for
protection and marketing and
shipped to customer.
Quality
z Mastering
y Disc master/stamper player
y Pit geometry checked with high power microscope
y PQ testing
Quality - Replication
z Samples from each run tested.
z Physical dimensions:
y thickness
y center hole diameter
z Analysis of electrical signals.
z Mechanical tests.
QA Tests & Signals
z Samples from each press for each run tested
y
y
y
y
y
Reflectivity
Asymmetry
Push Pull
Cross Talk
Birefringence
Mechanical Tests
z Mechanical tests that are run with the signal
tests include:
y
y
y
y
Radial noise
Eccentricity
Track pitch
Scan velocity
DVD Manufacturing
z DVDs are more difficult to manufacture
y Shallower pits and smaller pit size
y Smaller track pitch
y Tighter tolerances
Pit Sizes on a CD
DVD Bonding
z DVDs consist of 2 substrates bonded together.
z 3 processes can be used for bonding:
y Hot melt bonding
y Radical UV cured bonding
y Cationic UV bonding
CD & DVD Formats
z CD
z DVDs
y
y
y
y
650 MB
Single layer, single sided 4.7 GB
Single layer, double sided 9.4 GB
Dual layer, single sided
8.5 GB
Dual layer, double sided
17.0 GB
DVD Formats
z Single layer, single sided DVDs - active
substrate is metallized and bonded to blank
substrate.
DVD Formats
z Single layer, double sided DVDs - both
substrates are metallized and bonded together.
DVD Formats
z Dual layer, single sided DVDs - one substrate
has 2 metallization layers.
DVD Formats
z Dual layer, double sided DVDs - both
substrates have 2 metallization layers.
Future
z New technologies like blue lasers will increase
capacities.
z By 2005, it is predicted DVDs will have
capacities of 50 GB per side.