THE MASS PRODUalON OF THIN FILM HARD DISKS 
Thin film magnetic media is inherently more efficient than particulate iron oxide. Now with the introduction of the Eikon Series 600 disk, thin film is also more cost effective. 
The traditional magnetic storage media has been particulate iron oxide. However, as performance demands have increased in the disk drive industry, it has become clear that particulate iron oxide has definite limits. A good percentage of the surface is a nonmagnetic glue, and the size of the particles limits how closely the read/ write head may approach the surface. Thermal sensitivity and magnetostriction cause adverse fluctuations in magnetic charactertistics. 
Eikon produces an electrolytically plated thin film rigid disk capable of bit and track densities twice as great as particulate media, with improved signal to noise ratio, very low defect density, and lower manufacturing cost. 
The disk is intended for use in disk drives with a recording density of 12,000 to 16,000 flux changes per inch and track densities in excess of 1200 tracks per inch. 
LASER SCRIBING 
MAGNETIC CHARACTERISTICS OF EIKON SERIES 600 

The area of the hysteresis loop measures the energy dissipated during a cycle of magnetization. Excellent squareness and switching field distribution are shown. 
Typical magnetic characteristics of a Series 600 disk: coercivity of 600 oersted, remanence of 8000 gauss, and squareness of 0.9. 
Each disk is scribed by laser with a bar code and alphanumeric serial number. As the disks move through the manufacturing process, this bar code is read by laser scanners at each step. A complete process history is generated for every disk produced. 

MAGNETIC PLATING ROOM 
Virtually every manufacturing step is automated. The only human handling is in moving cassettes; all actual handling of disks is by robot or machine. 
REAL - TIME PROCESS CONTROL AND COMPUTER-AIDED MANUFACTURING 
Every stage of the manufacturing process is controlled and monitored by computer, with intensive computer control in deposition of the thin magnetic film. Eikon has chosen electrolytic plating because of its technical superiority, proven capabilities, and flexibility: magnetic characteristics are easily varied to meet customer specifications. 
Eikon has dedicated a network of computers to process control. In the plating rooms, computers sample each bath every few minutes, automatically adjusting the bath as needed to maintain correct chemistry at all times. The computer also monitors and controls bath environmental factors such as pH and temperature. 
The computer control system generates quality control statistics at each stage of manufacture. This data summary and analytical feedback system detects changes in yield at any manufacturing stage and ensures processes are kept in control. 

NICKEL P~ATING 
OPTICAL INSPECTION 
At this robotic work station each disk goes through 1 optical scanner to check for surface defects before _"'tering the critical magnetic plating process. 
"The first 12-micrometer film of nickel is nonmagnetic and is intended to improve the surface of the aluminum substrate. Nickel is highly polishable and provides a hard, clean tTletal- to- metal bonding surface for the iater magnetic plating. 
Several hundred disks are processed "simultaneously. The baths are sampled every few minutes to analyze bath chem"istry, which is automatically adjusted by the 'computer based upon real- time analysis of the sample data. 
POLISHING 
Disks are loaded into cartridges, which then go into the polisher, where both sides are polished by a diamond slurry. Polished surfaces have a typical peak-to-valley finish of less than .0625 micrometer. 
SCRUBBER 
Designed to the stringent requirements necessary to clean silicon waters in the microchip industry, this automated scrubber removes polishing residue" from the disks. 

MAGNETIC PLATING 
FINAL TESTING 
In the automated glide te5ler. a pieLoelertri( head flies .30% lower than a regular reao/write head. Disks with imperfect surfaces can easoily hp isolated. At a robqlic work station. el'1troni( certifiers test each aisk for amplitude. sil';nal-tonoise ratio. overwrite. and resolution. Defect testing of 2000 tracks per inch is standard for missing / extra pulses ano positive / negative modulation. 
The disks are electrolytically plated with a film of cobalt / nickel I phosphorous .075 micrometers thick. A specially designed dedicated robotic unit loads and unloads the plating tools used in the line. This proprietary plating process is tied into its own real-time, computercontrolled chemical analysis system. 
SPUTTERED CARBON OVERCOAT 
Eikon disks are hardier because of a .075 micrometer overcoat. In a vacuum chamber, a final protective layer is sputtered onto the disk surface. This film reduces corrosion, protects the surface 
from head contact dam- 
age, and improves 
friction/stiction 
characteristics. 
SCANNING ELECTRON MICROSCOPE 
A complete defect analysis laboratory. featuring a scanning electron microscope, helps assure quality at every step of the process.