LONG Description of Disk Manufacturing process.....from HMTT
5/96 prospectus........
MANUFACTURING AND QUALITY
HMT believes that its internally developed proprietary and patented
manufacturing processes and state-of-the-art equipment, to which it has made
proprietary modifications, combined with its extensive expertise, currently
provide HMT with a technological advantage over competing independent thin film
disk manufacturers. HMT's expertise, processes and equipment also allow it to
develop new proprietary processes in response to customers' requirements for
improved product performance and to integrate new technologies into the
manufacturing process rapidly. The Company's production lines can be installed,
modified or expanded on a cost efficient basis. The use of a modular strategy
facilitates incremental capacity increases, efficient adaptation of
manufacturing equipment for new product processes and achievement of high volume
manufacturing capacity for new products on a timely basis.
Manufacturing Process
The Company's manufacturing process is briefly summarized as follows:
Chamfer, Grind, Bake and Wash. The initial input to the production of a
thin film disk is an aluminum blank that can be procured from a number of
sources. To create specialized aluminum alloy substrates, the manufacturer
chamfers the sharp inner and outer edges of the blank, rough grinds the blank to
achieve flatness, bakes the blank to bring out surface roughness, final grinds
to remove surface defects and improve surface finish, and then washes the blank
to remove particles. HMT manufactures a portion of its requirements for these
substrates, which must be flat, smooth and free of surface defects, and
purchases the balance of its requirements from independent vendors.
Plate, Polish, Texture and Wash. Aluminum substrates are plated with
electro-less nickel, a non-magnetic layer critical to corrosion resistance that
strengthens the disk and improves durability. The Company currently performs
most of its nickel plating in-house. Disks are then polished to produce a mirror
smooth surface. Polishing enhances the nickel surface, reducing its roughness,
while maintaining the overall flatness of the disk. The Company's texturizing
process, a highly automated patented process, produces a controlled roughness on
the disk's surface to improve its stiction characteristics. The final step in
these front-end processes is washing to present a clean disk surface. Subsequent
processes occur in class 10 clean rooms.
Sputter, Dip Lube and Kiss Buff. The sputter process uses equipment and a
process, similar to that used in silicon wafer fabrication, in which layers of
materials are deposited on the disk through a vacuum sputtering process. The
chrome and magnetic layers determine the magnetic properties of the disk. The
carbon layer is a protective overcoat. After sputtering, a microscopic layer of
lubrication is applied to the disk's surface to improve durability and reduce
surface friction. After lubrication, a surface finishing step is applied,
commonly referred to as kiss buff or tape burnish.
Glide/Certify. In the test and certification process each finished disk is
electronically screened and certified as acceptable based on the customer's
specifications. A robotically controlled tester electronically tests for glide
performance. The tester then writes information onto the disk, reads it back and
erases it, simulating performance in the customer's disk drive. Each disk is
tested for parametrics, errors in the read/erase process and surface defects.
The conversion of a specialized aluminum alloy substrate into a final
product requires three to five days.
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Some other excerpts worth noting....
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TECHNOLOGY
The Company believes that there are a number of factors that are key to
establishing and maintaining an advanced technology position. The Company is
optimizing non-precious metal alloys, based on a cobalt/chromium/tantalum alloy,
for future products with coercivities that can support foreseeable demand for
increased storage capacity using relatively inexpensive materials. The Company
also has extensive expertise in the deposition of these and other alloys onto
disks. The Company uses state-of-the-art static sputtering machines in the
development and production of disks. Static machines differ from in-line, pallet
machines used by some other disk manufacturers in a number of important
respects. Static sputtering machines process one stationary disk at a time,
allowing for greater control of alloy deposition and minimizing spatial and
temperature variation; use isolated process chambers, permitting the
manufacturer to control and optimize each process step separately;
and do not require a pallet, reducing the risk of contamination of the disk
surface during processing. The Company has further enhanced the performance of
sputtering equipment supplied by vendors through internally developed,
proprietary and patented modifications.
The Company believes its unique tribology approach, which minimizes
detrimental interaction between the head and disk, is another area of strength.
The method involves balancing the inter-relationship between texturizing, carbon
overcoating and lubrication. The Company's patented graded zone texture process
allows the Company to produce a rougher texture at the disk's inner diameter,
while creating a smoother surface on the remainder of the disk. This process
provides increased protection where the head most often comes into contact with
the disk, while also minimizing the distance between the head and the disk
magnetics in other regions of the disk where data is stored and read. A
nitrogen-containing carbon overcoat offers superior wear resistance. Application
of the Company's in-house blended lubricant results in disks that can withstand
an extreme range of temperature and humidity conditions. These additional layers
must be thick enough to achieve the desired protection of the disk and thin
enough to minimize the distance between the head and the magnetic layer of the
disk. The Company believes that its application of these technologies, with
particular attention to the inter-relationship between the technologies and
their combined effect on disk performance, have enabled it to develop
competitive high-capacity disks
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According to Trend Focus, the number of thin film disks produced in 1993 was 134 million, in 1995 was 256 million and is projected to reach 416 million in 1997. The worldwide market for thin film disks is estimated to have been $3.3 billion in 1995.
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- Develop Advanced Manufacturing Processes to Support Volume
Production. HMT develops advanced manufacturing processes directly on
state-of-the-art production equipment. Developing manufacturing processes
for new products directly on active production lines during the research
and development phase increases the likelihood that the Company can
quickly and efficiently transition to high volume commercial production
of new products. The ability to implement new processes quickly also
helps the Company meet its customers' increasingly rapid time-to-market
demands and advances its goal of having its products designed into its
customers' disk drives.
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