Browse Prior Art Database

Multiple Disk Load/Unload for Sputter System

IP.com Disclosure Number: IPCOM000113676D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 103K

Publishing Venue

IBM

Related People

Bianchini, JM: AUTHOR [+7]

Abstract

A more efficient means was required to load small disks--65mm (2.56in) and smaller--from carrier cassettes into vertical pallets which support them during the sputter process of hard storage disk manufacture, then to unload them on completion of the process.

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This is the abbreviated version, containing approximately 52% of the total text.

Multiple Disk Load/Unload for Sputter System

      A more efficient means was required to load small disks--65mm
(2.56in) and smaller--from carrier cassettes into vertical pallets
which support them during the sputter process of hard storage disk
manufacture, then to unload them on completion of the process.

      Automated loading is required to maintain cost effective
throughput rate.  A typical pallet (Figure) is an aluminum plate
thicker than the disks it must hold with holes cut in it to
accommodate them.  The disks are held in place in the pallet by a
tapered groove at the bottom and sides of each hole.  The groove must
be shallow enough to minimize disk shadowing--that is, masking of the
disk surface as the sputter is applied--yet deep enough to hold the
disk securely throughout the process.  Because of temperature
variations encountered during the sputter process (from 200ºC to
normal room temperature), the combined effects of surface warpage
plus expansion and contraction make it difficult to determine with
sufficient accuracy the spacing between loading centers or the exact
location of the groove in each hole across the entire pallet.
Accuracy in loading is vital, since a misloaded disk that becomes
dislodged during processing can result in costly process interruption
or loss of product.

      In prior art, a robot loading a pallet could reliably place
only one disk at a time; the only way to increase throughput,
therefore, was to use multiple robots to gang load the pallets, but
this incurs the cost of providing additional clean-room space to
accommodate them.  But if the pallet surface is mapped just prior to
loading, so that the actual loading centers are located with
certainty, then the local distortion from expansion/contraction and
warpage will be slight enough on loading centers directly adjacent to
each other that several disks--the exact number depending on their
size--can be reliable loaded at once.  By permitting a single robot
to load several disks at a time while eliminating the danger of
misloads, the Multiple Disk Load/Unload mechanism disclosed herein
satisfied these requirements, achieving a greater than 40%  increase
in the production rate of 65mm disks and comparable improvements with
smaller disk sizes.

      As shown in the Figure, the Multiple Disk Load/Unload mechanism
consists of the following components:

      Input buffer 1 is the station into which a cassette 2 is placed
prior to sputtering; the pic...