WO2000020167A2

WO2000020167A2 - Method and apparatus for automatically polishing magnetic disks and other substrates

Info

Publication number: WO2000020167A2
Application number: PCT/US1999/023182
Authority: WO
Inventors: Roger O. Williams; Jeff Howard; Tarlochan Singh; Nathan Jones; James R. Aven; Leroy J. Serpa; Lawrence Lee; Mike Vantuyl; Lindsey Hamilton; Sean O'donnell; Michael J. Herrmann; Kevin Thompson; Jon F. Nystedt; Matt Richardson
Original assignee: Exclusive Design Company, Inc.
Priority date: 1998-10-05
Filing date: 1999-10-05
Publication date: 2000-04-13
Also published as: WO2000020167A9; WO2000020167A3; JP2000187832A; AU6508699A

Abstract

A substrate polishing apparatus for sequentially polishing both sides of a substrate, such as a magnetic disk, and method therefor, are provided. The apparatus according to the present invention may be conveniently considered in terms of it's subassemblies. The apparatus includes a cassette/disk handling robot (104), a disk flip and rinse station (106), an orbiter (110) including disk polish heads (112), a main gantry robot (108) and a magazine (114) having a polish platen (116) and supplying a polish tape or web tape (115) on which the substrate is polished. The disk flip and rinse station (106) receives a substrate from the cassette/disk handling robot (104) and subsequently releases the substrate back to the cassette/disk handling robot (104). The main gantry robot (108) moves the orbiter (110) and the disk polish head (112) to retrieve the substrate from the disk flip and rinse station (106) for polishing and to release the substrate back to the disk flip and rinse station (106) after polishing. The method according to the invention generally comprises the steps of polishing the first side of a substrate, automatically inverting the substrate and polishing the second side.

Description

METHOD AND APPARATUS FOR AUTOMATICALLY POLISHING MAGNETIC

DISKS AND OTHER SUBSTRATES

COPYRIGHT AUTHORIZATION A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyrights whatsoever. FIELD OF THE INVENTION

The present invention relates generally to machines for polishing disk substrates. In particular, the present invention relates a method and system for automated loading, polishing, and unloading of magnetic disk substrates.

BACKGROUND OF THE INVENTION

Current methods for polishing a disk substrate include planetary polishing in which a set of disks is sandwiched between two oppositely rotating plates. Approximately 5 or 6 disks are housed within a flat, circular fiberglass ring, and several rings are positioned in a circular fashion between the rotating plates. As the plates rotate, the rings also rotate about the axis of the plates such that the rings move in a retrograde trajectory. In this manner, the velocity at each point on the surface of the disk is different resulting in a non- uniform polish. Therefore, the plates are operated for a long period of time so that the average velocity at each point on the surface of a disk, and the resulting polish, will be uniform. In operation, the circular fiberglass rings of these prior art systems deteriorate over time, and chips of fiberglass actually break off from the rings. These chips may then scratch the disks being polished. Furthermore, the web tape used for polishing is exposed to uneven wear due to the nature of planetary rotation which also contributes to non-uniform polishing. Lastly, the size of a planetary polishing apparatus is large, requiring a large room to house the apparatus and to operate it. While advances have recently been made in the art related to chemical-mechanical polishing (CMP) of silicon wafers, see, for example U.S. patent No. 5,759,918, these advances are not readily translatable to disk polishing because of the requirement of two sided polishing for magnetic disk substrates. Accordingly, it would be desirable to provide an improved substrate polishing apparatus that provides for polishing of both sides of disk substrates wherein constant polishing friction may be achieved over the life of the polishing web material. It would be further desirable to provide a polishing apparatus capable of continuous operation in an assembly line fashion requiring a minimum of human interaction.

It would be further desirable to provide a polishing apparatus capable of achieving commercially acceptable substrate throughput levels while having a smaller size and lower cost of operation to maximize factory floor space utilization while lowering the cost of disk production.

SUMMARY OF THE INVENTION

A substrate polishing apparatus for sequentially polishing both sides of a substrate, and method therefor, are provided. The apparatus according to the present invention may be conveniently considered in terms of its subassemblies. The apparatus includes a cassette/disk handling robot, a disk flip and rinse station, an orbiter including disk polish heads, a main gantry robot and a magazine having a polish platen and supplying a polish tape or web tape on which the substrate is polished. The disk flip and rinse station receives a substrate from the cassette/disk handling robot and subsequently releases the substrate back to the cassette/disk handling robot. The main gantry robot moves the orbiter and the disk polish head to retrieve the substrate from the disk flip and rinse station for polishing and to release the substrate back to the disk flip and rinse station after polishing. The method according to the invention generally comprises the steps of polishing the first side of a substrate, automatically inverting the substrate and polishing the second side. In a preferred embodiment, a method is presented for polishing planar members having first and second opposed sides, comprising presenting the member at a polish location with the first side oriented toward a polish media, polishing the first side against the polish media, removing the member from the polish location, inverting the first substrate to orient the second side toward the polish media, presenting the member at the polish location with the second side oriented toward the polish media, and polishing the second side against the polish media. The planar member may be a magnetic disk substrate.

In another embodiment, the removing step comprises translating the member to a position remote from the polish position and depositing the member at the remote location, and in another embodiment, the inverting step comprises inverting the member at the remote location.

In yet another embodiment, the member is placed at the remote location prior to initially presenting the member at the polish location and wherein the presenting steps each comprise retrieving the member from the remote location and translating the member to the polish location.

In another embodiment, a series of members D, _{(l =} , _{t0 n)} are sequentially polished with each subsequent member in the sequence (D,₊₁) being delivered to the remote location during at least one of the presenting and polishing of the preceding member (D,). in another embodiment, the remote location comprises a deposit position and a retrieval position, the inverting step comprises transferring the member from the deposit position to the retrieval position, the depositing step comprises depositing the member at the deposit position, and the retrieving step comprises retrieving the member from the retrieval position. Further, the placing step may comprise translating the member from an initial position and placing the member at a pre-retrieval position, wherein the remote location may additionally includes the pre-retrieval position.

In another embodiment, a series of members D, ₍ , ₌ , _{t0 n)} are sequentially polished, with each subsequent member in the sequence (D_l+]) being delivered to the remote location during at least one of the presenting and polishing of the preceding member (D,), and further comprising the steps of: (a) placing a subsequent member (D_l+1), (b) removing a preceding member (D,), (c) transferring the subsequent member (D,₊,) from the pre-retrieval position to the retrieval position, (d) retrieving the subsequent member (D,_{+ 1}) after steps (a)- (c), (e) translating the subsequent member (D,₊₁) to the polish position, (f) inverting the preceding member (D,) after step (d), and (g) polishing the first side of the subsequent member (D_jN).

In another embodiment, the above steps may include the steps of: (h) removing the subsequent member (D,_+|), (i) presenting the preceding member (D,) with the second side oriented toward the polish media, (j) polishing the second side of the preceding member (D,), (k) inverting the subsequent member (D,N), (1) removing the preceding member (D,), (m) presenting the subsequent member (D_l+I) with the second side oriented toward the polish media, and (n) polishing the second side of the subsequent member (D,N). In yet another embodiment, these steps may include the steps of: (o) moving the preceding member (D,) to the pre-retrieval position, (p) transferring the preceding member (D,) from the pre-retrieval position to an exit position, (q) placing a further member (D₁₊₂), and (r) repeating steps (b) - (q) with respect to members D,₊₂ through D_n. In another embodiment, an apparatus is provided for moving a cassette for holding a substrate and for moving a substrate without contacting the surface of the substrate comprising a robot body attached to a horizontal drive screw assembly, a vertical drive screw assembly attached to the robot body and an end effector attached to the vertical drive screw assembly and having a first passive finger for moving the substrate by only contacting an edge of the substrate and a cassette hook for lifting a cassette for holding the substrate.

In another embodiment, an apparatus is provided for receiving a substrate, presenting the substrate to a disk polish head and inverting the substrate, comprising a compartment, a presenter mechanism attached to the bottom of the compartment, a holder mechanism attached to the bottom of the compartment opposing the presenter mechanism and a disk flipper mechanism having a disk holder and rotatably attached to the compartment and positioned to rotate back and forth between the presenter mechanism and the holder mechanism. In another embodiment, an apparatus is provided for imparting orbital motion to a disk polish head which retains a substrate to be polished comprising a motor which drives an orbiter rotation gear, an orbiter shaft connected to an off-centered point on the orbiter rotation gear such that the orbiter shaft moves in an orbit upon rotation of the orbiter rotation gear, and having an upper end and a lower end, a solid connector bar which is fixedly connected to the lower end of the orbiter shaft and which is connected to the disk polish head, and an anti-rotation mechanism connected to the upper end of the orbiter shaft.

In another embodiment, an apparatus is provided for retaining a substrate during polishing comprising a seal plate, a disk plate attached to the bottom of the seal plate, a ring disk carrier attached to the bottom of the seal plate and about the circumference of the disk plate and a plastic retainer ring attached to the bottom of the ring disk carrier and about the circumference of the disk plate.

In another embodiment, an apparatus for supplying web tape for polishing a substrate comprising a supply roller having a roll of web tape, a take-up roller for collecting used web tape and wherein the supply and the take-up rollers are removable. In another embodiment, a computer program product is provided for controlling an automated substrate polishing apparatus, the automated substrate polishing apparatus having a plurality of mechanical subsystems for achieving successive substrate polishing steps, comprising a first computer code module for controlling a first mechanical subsystem that achieves a first substrate polishing step and a second computer code module separate from the first computer code module for controlling a second mechanical subsystem that achieves a second polishing step responsive to the completion of the first substrate polishing step, wherein the second computer code module actuates the second mechanical subsystem responsive to a global handshake received from the first computer code module, whereby the computer program product controls the automated substrate polishing apparatus in an event-oriented manner that does not require schedule-based control of successive mechanical subsystems of the automated substrate polishing apparatus.

In another embodiment, a method for calibrating a substrate polishing apparatus is provided by computing transfer function constants, the transfer function constants for use by the polishing apparatus in computing a control pressure vector from a user-entered output vector during normal operation, comprising the steps of applying a calibration set of control pressure vectors, the calibration set substantially spanning the space of possible control pressure vectors capable of being used in the operation of the polishing apparatus, measuring an actual output vector corresponding to each control pressure vector in the calibration set and computing the transfer function constants using information derived from the actual output vectors and the calibration set of control pressure vectors.

In another embodiment, a portable calibration device is provided for calibrating a plurality of substrate polishing machines each having at least one disk polish head, each of the substrate polishing machines being coupled to a local area network, the portable calibration device comprising a frame for removable mechanical coupling to one of the substrate polishing machines near the polish head thereof, a sensor for measuring an output force and converting the measurement into digital form and a digital input/output device for coupling to the local area network, wherein the local area network is used to communicate the measured output force to the substrate polishing apparatus producing that output force, whereby the portable calibration device can be used for a plurality of substrate polishing machines without requiring the establishment of a separate physical data link to each respective one of the substrate polishing machines.

The present invention provides a method and apparatus which efficiently and uniformly polishes both sides of a substrate automatically. Furthermore, the present invention provides an apparatus and method for polishing multiple substrates simultaneously. The present invention also provides an apparatus that is considerably smaller than other devices for polishing substrates. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A is an isometric view of a preferred embodiment of the apparatus of the present invention;

FIG. IB is an exploded view of the embodiment shown in FIG. 1A; FIG. 1 C is a cross-sectional schematic representation of the embodiment shown in FIG. 1A;

FIG. ID is a front and right side isometric view of the embodiment shown in FIG. 1 A with the upper frame removed;

FIG. IE is a rear and left side isometric view of the embodiment shown in FIG. 1 A with the upper frame removed;

FIG. 2A is an isometric view of one embodiment of the cassette/disk handling subassemblies according to the present invention;

FIG. 2B is a more detailed view of the cassette/disk handling robot shown in FIG. 2A: FIG. 2C is a cross-sectional view of one embodiment of a submerged conveyor stop mechanism according to the present invention;

FIG. 3 A is a partly-exploded view of one embodiment of a disk flip and rinse station according to the present invention;

FIG. 3B is an exploded view of one embodiment of a submerged hydrodvnamic substrate presenter mechanism according to the present invention; FIG. 3 C is an exploded view of one embodiment of a submerged hydrodvnamic substrate holder mechanism according to the present invention:

FIG. 4A is an isometric view of one embodiment of a main gantry robot according to the present invention; FIG. 4B is a partial cross-sectional view of one embodiment of a carrier table brake for use with the main gantry robot according to the present invention.

FIG. 4C is an isometric and schematic view of one embodiment of a motion restraint apparatus for use with a robot as in FIG. 4A.

FIG. 5 A is an isometric view of one embodiment of an orbiter vertical motion robot and an orbiter according to the present invention;

FIG. 5B is a view of a preferred embodiment of an orbiter mechanism; FIG. 6 is an isometric view of an alternative orbiter; FIG. 7A is cross-sectional view through lines 7A-7A in FIGS. 5A and 6 of one embodiment of a disk polish head and supporting column according to the present invention: FIG. 7B is a plan view of one embodiment of a disk polish head flexure according to the present invention;

FIG. 8 is an exploded view of an embodiment of a bearing assembly including an elliptical differential radius bearing according to the present invention; FIG. 9 is partly-exploded isometric view of one embodiment of a calibration fixture according to the present invention;

FIG. 10 is a partial cross-sectional view along the same orientation as FIG. 7A illustrating a further alternative embodiment of a disk polish head according to the present invention; FIG. 1 1 is a cross-sectional view of one embodiment of an air bearing disk plate according to the present invention;

FIG. 12 is a partial cross-sectional view of another embodiment of a disk polish head according to the present invention;

FIG. 13 is a schematic view of one embodiment of one embodiment of a system for using water pressure to lift and release a disk according to the present invention;

FIG. 14 is a partial cross-sectional view of one embodiment of a disk pickup manifold system according to the present invention;

FIG. 15 is not used;

FIG. 16A is a front and right side isometric view of one embodiment of a magazine according to the present invention;

FIG. 16B is an elevational view of the magazine shown in FIG. 16A.

FIG. 16C is a partially exploded isometric view of one embodiment of a conditioning roller according to the present invention;

FIG. 16D is an elevational view of one embodiment of a diamond embossed pattern on the conditioning roller shown in FIG. 16C;

FIG. 16E is a plan view of the diamond embossed pattern on the conditioning roller shown in FIG. 16C;

FIG. 16F is an exploded view of one embodiment of a polish platen according to the present invention; FIG. 17 is a block diagram of an overall control system used to control a substrate polishing apparatus in accordance with the preferred embodiments;

FIG. 18 is a block diagram of a software program loaded in a central processing unit corresponding to the control system of FIG. 17;

FIG. 19 shows a flow diagram of an event-driven software module; FIG. 20 shows the main menu of a user interface of the software program that controls a substrate polishing apparatus in accordance with the preferred embodiments;

FIG. 21 A shows a block diagram of the CONFIGURATION control software; FIG. 21B shows a user interface corresponding to the block diagram of the

CONFIGURATION control software of FIG. 21 A;

FIG. 22A shows a block diagram of the DIAGNOSTICS control software; FIGS. 22B and 22C shows a user interface corresponding to the block diagram of the DIAGNOSTICS control software of FIG. 22A with a first submenu item selected;

FIG. 23 A shows a block diagram of HELP software;

FIG. 23B shows a user interface corresponding to the HELP software of FIG. 23A;

FIG. 24 shows a block diagram of recipe management software; FIGS. 25 and 26 show recipe editor parameter screens;

FIG. 27 shows a recipe editor sequence screen; FIG. 28 is not used; FIG. 29 is not used;

FIGS. 30-1, 30-2 and 30-3 show steps taken by a substrate polishing apparatus with respect to a single disk in accordance with the preferred embodiments;

FIGS. 31-1 and 31-2 show steps taken by a substrate polishing apparatus with respect to two sets of disks in accordance with the preferred embodiments; FIG. 32 shows steps in disk pickup; FIG. 33 shows steps in disk release; FIG. 34 shows steps in securing a main gantry robot;

FIG. 35 shows steps used to control vertical forces exerted by disk polish heads;

FIG. 36 shows a data table that may be stored in computer memory for use during a calibration process; FIG. 37 shows steps used to determine the calibration constants based on measurements taken during a calibration process;

FIG. 38 shows a data table that may be stored in computer memory for dictating possible combinations of calibration samples for use in determining calibration constants; and FIG. 39 shows a user interface for viewing parameters associated with the forces exerted by disk polishing heads during calibration and/or operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A substrate polishing apparatus in accordance with a preferred embodiment of the invention provides an apparatus and method for automatically polishing both surfaces of a substrate such as a magnetic disk. Below, a general overview of the apparatus and method of the present invention is presented, followed by a detailed description of each particular component within the present invention, including the computer control system. A detailed description of the complete process operation and calibration procedures will then be described. It should be recognized that the headings used below are to assist in broadly organizing the description of the invention and are not intended to be limiting in any manner, since description of certain aspects of the invention may be found under several headings.

System Overview

As illustrated in FIGS. 1 A-E, a preferred embodiment of a substrate polishing apparatus 100 of the present invention comprising several general components or sub- assemblies. in general operation, with particular reference to FIGS. IB and 1C, cassettes

(represented by cassette in arrow Cl) carrying a plurality of disks to be polished are placed on a dry conveyor 102 and are moved from a loading station to a pickup station which is a position aligned with a cassette/disk handling robot 104. Robot 104 first moves the cassette from dry conveyor 102 to staging position B. The cassette/disk handling robot 104 also moves the individual disks from the cassettes at position B to a disk flip and rinse station 106. A main gantry robot 108, which houses an orbiter 1 10, a plurality of disk polish heads 112 and an orbiter vertical motion robot 1 13, moves into position to allow the disk polish heads 112 to pick up the disks from station 106. Main gantry robot 108 then moves disk polish heads 1 12, holding the disks, to a polish station P over magazine 1 14. Magazine 1 14 supplies a web tape 1 15 which is fed over a polish platen 1 16 upon which the disks are polished. Orbiter vertical motion robot 1 13 lowers orbiter 1 10 and disk polish heads 1 12 to a predetermined point above polish platen 1 16 and pressure is applied to the disk polish heads 1 12 to achieve sufficient contact between the disks and polish platen 1 16. The disks are then polished by orbiter 1 10 which causes disk polish heads 1 12 to move in a circular orbit on the web tape 1 15 upon which polish slurry has been placed. The disks are then transferred back to the disk flip and rinse station 106 where they are first rinsed and then flipped over and again retrieved by the main gantry robot 108. The other side of the disk is polished and rinsed in the disk flip and rinse station 106. The disk is then picked up from rinse station 106 by robot 194 which transfers the disk to an empty cassette at position W submerged on wet conveyor 1 18. Wet conveyor 1 18 transfers the submerged cassettes containing polished disks to a point where they are retrieved manually or automatically by another machine as indicated by arrow CO.

Other components of the substrate polishing apparatus 100 include a computer control system 120 which controls the entire process, a deionized water system

1 122 which filters and recycles water to various parts of the substrate polishing apparatus 100 and a HEPA air filtration system 124 which provides process air for use in the substrate polishing apparatus 100. A frame 126 is also shown upon which all of the components are mounted.

1 Cassette and Disk Handling

To allow the substrate polishing apparatus 100 to automatically and continuously polish disks, a transport mechanism for moving disks into and out of the substrate polishing apparatus 100 is needed. Furthermore, another mechanism is needed for retrieving disks from, and returning polished disks to, the transport mechanism.

20 FIG 2A shows the components used to transport cassettes C containing several disks

D to the substrate polishing apparatus 100. Specifically, the cassettes C are placed upon the dry conveyor 102 by a preceding and separate process step and are moved to a pickup station or position aligned with, and accessible by the cassette/disk handling robot 104 (Position A). The dry conveyor 102 can be any type of conveyor system capable of moving

25 the cassettes from an initial loading point where they are first placed on the dry conveyor 102 to a pickup station or position at the end of the dry conveyor 102 which is aligned with the cassette/disk handling robot 104. Conveyor 102 has a plurality of sensors (not shown) used to detect when the cassettes are in the correct position relative to the cassette/disk handling robot 104. It should be appreciated that the sensors are preferably also used to

30 detect the presence of a plurality of cassettes.

FIG. 2B shows in greater detail cassette/disk handling robot 104, which is used to simultaneously retrieve four cassettes C from the dry conveyor 102 and to subsequently retrieve individual disks D from each of the four cassettes. (Cassette/disk handling robot 104 also returns polished disks to the cassettes and places the cassettes on the

35 wet conveyor 1 18 for transport from the substrate polishing apparatus 100 as will be subsequently described.) The cassette/disk handling robot 104 is mounted on a horizontal drive screw assembly 204 which permits movement of the cassette/disk handling robot 104 in a horizontal direction that is normal to the dry conveyor where the cassettes are initially retrieved (Position A). Cassette/disk handling robot 104 further comprises an end effector 206 which is capable of moving four cassettes, and four individual disks from each cassette, in both a horizontal and vertical direction. End effector 206 preferably comprises an L- shaped frame 208 that is coupled by an end effector shaft 210 which can be moved vertically by a vertical drive screw assembly 211. End effector 206 further comprises four pairs of cassette hooks 212 for lifting cassettes from the dry conveyor and placing them on a stationary shelf 220 (Position B). These cassette hooks 212 are also used to move empty cassettes from the stationary shelf 220 to a submerged stationary shelf 221 and then ultimately to the wet conveyor 1 18 (Position A).

The end effector 206 also comprises four passive fingers 222 which in conjunction with the cassette/disk handling robot 104 are specially adapted to (i) passively lift four disks from each of four respective cassettes, (ii) maintain the disks at a substantially vertical orientation during translation to the disk flip and rinse station 106, (iii) allow the disk flip and rinse station 106 to seize control of the disks before polishing, (iv) allow the disk flip and rinse station 106 to transfer control of the disks to the end effector 206 after complete polishing and (v) maintain the disks at a substantially vertical orientation during translation from the disk flip and rinse station 106 to a submerged cassette. It should be appreciated that in a preferred embodiment the four passive fingers 222 are each capable of holding two disks, one on each side of the end effector 206. This allows the cassette/disk handling robot 104 to retrieve a set of four disks from the disk flip and rinse station 106 and, while positioned over the disk flip and rinse station 104, to drop off a different set of four disks. In this manner, the cassette/disk handling robot eliminates the step of returning polished disks to the cassettes before retrieving another set of disks to be polished.

In operation, the cassette/disk handling robot 104 moves horizontally and vertically to align the cassette hooks 212 with the cassettes and then moves horizontally to position the cassette hooks 212 along the sides of the cassettes. Once aligned, the cassette/disk handling robot 104 moves horizontally towards the cassettes and then vertically upward to lift the cassettes. These steps are reversed to release the cassettes. Similarly, to retrieve disks from a cassette, the cassette/disk handling robot 104 moves horizontally and vertically to align the passive fingers 222 with the center of the disks and moves horizontally to insert the passive fingers 222 into the center of the disks. The cassette/disk handling robot 104 then moves vertically upward to lift the disks. To release the disks back into the cassettes, the cassette/disk handling robot 104 moves horizontally above the cassettes and then vertically downward until the disks are secured in the cassettes. Once secured, the cassette/disk handling robot actually continues to move vertically downward to separate the passive fingers 222 from the disks before moving horizontally away from the cassettes. The procedure for releasing disks to, and retrieving disks from, the disk flip and rinse station 106 is discussed below.

The wet conveyor 118 is contained in a wet conveyor basin 229 which is filled with water, preferably deionized water. This permits the cassettes containing the polished disks to remain submerged to avoid any remaining polish slurry from drying on the disks. The polished disks in the cassettes are transferred to the end of the wet conveyor 1 18 for manual removal or automatic removal by another machine.

FIG. 2C shows the submerged conveyor stop mechanism 230 which is located at the end of the wet conveyor 1 18. The submerged conveyor stop mechanism 230 is designed to prevent movement of the wet conveyor 1 18 until a cassette is detected at the end of the wet conveyor 118. Once a cassette is detected the wet conveyor 118 will move the cassette to the end of the wet conveyor 1 18 for pickup. Furthermore, the submerged conveyor stop mechanism 230 is designed to operate underwater without the need for lubrication to prevent contamination of the water by such lubricating materials and is made of materials, such as plastic, that are not susceptible to corrosion by contact with water or any corrosive species in the water. The submerged conveyor stop mechanism 230, which comprises body 231 attached to wet conveyor basin 229 by a clamp 232. A piston 234 having a finger 236 is biased in the up position by a return spring 238. Finger 236 impacts the side wall of a cassette thereby preventing its passage along the wet conveyor 1 18. In a preferred embodiment, two submerged conveyor stop mechanisms are used on each side of the wet conveyor 118 to more uniformly stop the cassette. Fiber optic sensors (not shown) are position along the wet conveyor 1 18 to detect the presence of a cassette. When a cassette is detected, pressurized water is introduced into a water inlet 242 which forces the piston 234 and the finger 236 downward thereby initiating movement of the wet conveyor 118 and allowing a cassette to pass to the end of the wet conveyor 118.

Disk Flip and Rinse Station

FIG 3 A shows the disk flip and rinse station 106. The disk flip and rinse station 106 receives disks D from cassette/disk handling robot 104, flips disks to permit polishing of both sides, rinses the disks after polishing each side and releases the disks back to cassette/disk handling robot 104. The disk flip and rinse station 106 generally comprises body 302 divided into two water-tight compartments, a disk flip compartment 304 and a disk rinse compartment 306.

Disk flip compartment 304 contains a disk flipper 308, four submerged hydrodynamic substrate presenter mechanisms 316, four submerged hydrodynamic substrate holder mechanisms 336 and four weirs 360 surrounding each corresponding set of submerged hydrodynamic substrate presenter and holder mechanisms 316, 336, which act to maintain the water level surrounding each such set. The disk flipper 308 is mounted on a rotatable shaft 310. Four disk holders 312 are mounted on the disk flipper 308, each comprising a pair of disk holding fingers 314. The motorized rotation of the rotatable shaft

1 310 is controlled by the computer system 120 and is capable of rotating 180 degrees from horizontal and stopping at each horizontal position and at 90 degrees such that the disk flipper 308 would be in a vertical position. At each of these positions, each pair of disk holding fingers 314 is capable of receiving or releasing a disk. To receive a disk, each disk holding finger moves axially along the rotatable shaft 310 and in a direction opposite from

15 its pair thereby opening enough to allow a disk to be inserted between each pair of disk holding fingers 314. Upon receipt of the disk, each disk holding finger 314 returns to its closed position thereby securing the disk. To release a disk the steps used to receive a disk are reversed.

In operation, the disk flipper 308 receives disks from the end effector 206 of

20 the cassette/disk handling robot 104. In this step, the disk flipper 308 moves into the vertical position (the position shown in FIG. 1C) and the disk holding fingers 314 open to receive the disks. The cassette/disk handling robot 104 retrieves disks from a cassette and moves horizontally and vertically downward to a position horizontally aligned with the disk holding fingers 314. The cassette/disk handling robot 104 then moves horizontally such that

25 the disk is appropriately positioned within the disk holding fingers 314 which then close to secure the disk by its edges. The cassette/disk handling robot 104 then moves vertically downward to separate the passive fingers 222 from the disks center holes and moves horizontally away from the disk flipper 308. It should be appreciated that the disks are held by the passive fingers 222 on the side of the end effector 206 opposite the disk flipper 308 which allows the cassette/disk handling robot 104, after releasing the disks to continue moving unimpeded in the same horizontal direction beyond the disk flipper 308. After receiving the disks, the disk flipper 308 rotates 90 degrees to a horizontal position and releases the disks onto their respective submerged hydrodynamic substrate presenter mechanism 316. It should be appreciated that the disk flipper is one example of a rotatable

35 substrate holder which can accomplish rotating the disks. FIG. 3B shows the submerged hydrodynamic substrate presenter mechanism 316. The submerged hydrodynamic substrate presenter mechanism 316 operates to present the disks to the disk polish heads 1 12 for pickup. The submerged hydrodynamic substrate presenter mechanism 316 comprises a presenter base 318 connected to the bottom of the disk flip compartment 304 and having a vertically extending cylinder 319. An upper presenter body 320 is slidably connected to the presenter base 318 and is propelled upward by water pressure injected into a presenter passageway 322 located in the center of the presenter base 318 and extending vertically through the presenter base 318 and the vertically extending cylinder 319. The presenter passageway 322 is open at the top of the vertically extending cylinder 319. Water injected into the bottom of the presenter passageway 322 will impact the bottom of the upper presenter body 320 thereby propelling it vertically upward. Vertical travel is restricted by a presenter travel pin 324 which extends from the upper presenter body 320 into a vertical slot 326 in the presenter base 318. Connected to the upper presenter body 320 is a tapered, cylindrical post slip fitting 328 whose diameter is at least approximately less than the inside diameter of the center hole. The tapering of the post slip fitting 328 allows for any misalignment of the disk when placed on the submerged hydrodynamic substrate presenter mechanism 316. The post slip fitting 328 fits inside a sleeve press fitting 330 attached to the top of the upper presenter body 320. Between the top of the upper presenter body 320 and the post slip fitting 328 is a compression spring 332 that biases the post slip fitting 328 in an upwardly extended position. The upper presenter body 320 has a plurality of water passages 334 which allow for drainage of any fluid retained within the sleeve press fitting 33^*0. All of the parts of the submerged hydrodynamic substrate presenter mechanism 316 are made of either plastic or stainless steel. In particular, upper presenter body 320 is made of stainless steel as its own weight is used to return it to its lower position after it has been vertically extended, as described below.

In operation, the disk flipper 308 releases the disks onto their respective submerged hydrodynamic substrate presenter mechanism 316, during which no water is injected into the presenter base 318. The disks actually rest on a top edge 329 of the upper presenter body 320 which is submerged. When the disk polish heads 1 12 are lowered by the orbiter 1 10 to retrieve the disks, water is injected into the presenter base 318 propelling the upper presenter body 320 upward. The disk polish heads 1 12 press down on the post slip fitting 328 thereby squeezing the compression spring 332 to ensure complete contact between the disk polish heads 1 12 and the disks. After the disk polish heads 1 12 have retrieved the disks, water injection is discontinued and the upper presenter body 320 will fall of its own weight back to its lower position. FIG. 3C shows the submerged hydrodynamic substrate holder mechanism 336. After polishing, which is described below, the disk polish heads 1 12 release the polished disks onto the submerged hydrodynamic substrate holder mechanism 336. The submerged hydrodynamic substrate holder mechanism 336 comprises a holder base 338. having a vertically extending cylinder 340 which is connected to the bottom of the disk flip compartment 304. An upper holder body 342, which is cylindrical with a conical upper portion, is slidably connected to the holder base 338 and is biased in an upward position by a compression spring 344. Vertical travel is restricted by a holder travel pin 346 which extends from the holder base 338 into a vertical slot 346 in the upper holder body 342. Formed at the top of upper holder body 342 is tapered fitting 348 . Fitting 348 receives the disks, which ultimately rest upon the top edge 349 of the upper holder body 342. Holder base 338, upper holder body 342 and tapered fitting 348 form a passageway 350 which permits water to be introduced at the bottom of the holder base 338 and spray out of opening 352 in the tapered fitting 348 which contains a cone spray nozzle 351. In operation, when disk polish heads 1 12 release disks onto the submerged hydrodynamic substrate holder mechanism 336, water is pumped through the submerged hydrodynamic substrate holder mechanism 336 to wash polishing slurry from the bottom of the disks. To provide an adequate and unimpeded spray of water, the top of hydrodynamic substrate holder mechanism 336 is slightly above the water level. The disk polish heads 1 12 push down against the force of the compression spring 344 to ensure accurate release of the disks. It should be appreciated that the top edge 349 of the upper holder body 342 is below the water level so that the disks are submerged to avoid slurry drying on the disks.

Disk flipper 308 retrieves disks placed on the hydrodynamic substrate holder mechanism 336 by the disk polish heads 1 12 and flips these disks over to the hydrodynamic substrate presenter mechanism 316. This allows the other side of these disks to be polished, as the disk polish heads 1 12 will retrieve the flipped disks, with the unpolished side down, from the hydrodynamic substrate present mechanism 316 for further polishing. During this flipping step, it should be appreciated that the top edge 329 of the upper presenter body 320 upon which the disks rest after flipping (FIG. 3B) and the top edge 349 of the upper holder body 342 upon which disks rest before flipping (FIG. 3C) are both submerged and at equivalent heights to allow the disk flipper 308 to pickup, flip and release the disks by rotating 180 degrees.

Once both sides of the disks have been polished, the disk flipper 308 acts to release the disks to the cassette/disk handling robot 104 for translation back to the cassettes which have been placed on the submerged stationary shelf 221 by the cassette/disk handling robot 104. The disk flipper 308 retrieves the disks from the submerged hydrodynamic substrate holder mechanism 336 and moves into a vertical position as shown in FIG. lC. The cassette/disk handling robot 104 moves horizontally so that the passive fingers 222 move into the hole in the center of the disks, respectively. The cassette/disk handling robot then moves vertically upward to secure the disks on the passive fingers 222, and the disk holding fingers 314 open to release the disks. It should be appreciated at this point, that the cassette/disk handling robot next moves horizontally to release another set of four disks, held by the opposite side of the passive fingers 222 to the disk flipper 308 before returning the polished disks to the submerged stationary shelf 221. The disk rinse compartment 306 is designed to rinse the disks immediately after polishing. The disk rinse compartment 306 is separated from the disk flip compartment 304, since this rinse step will produce water more contaminated with slurry than that in the disk flip compartment 304. The disk rinse compartment 306 comprises four pairs of spray nozzles 354 angularly offset from each other such that upon receiving water for spraying each pair of spray nozzles 354 rotates about a vertical axis. In operation, after each polishing step the disk polish heads 1 12 move to a position above the disk rinse compartment 306 and are lowered by the main gantry robot 108 into the disk rinse compartment 306. The spray nozzles 354 spray the disks to rinse polishing slurry from the disks. Additionally, the disks may also be submerged into the water contained in the disk rinse compartment 306. The spray nozzles 354 can be commanded to continue to spray the disks as they are lifted from the disk rinse compartment 306. During this rinse step the disks are preferably retained on the polish heads.

Deionized water is used in the disk flip compartment 304 and in the disk rinse compartment 306. Water is typically recycled and filtered by the deionized water system 122 which comprises a pumping system and filtering system.

Main Gantry Robot, Orbiter Vertical Motion Robot, Orbiter, and Polish Heads

FIG 4A shows the main gantry robot 108 which carries orbiter vertical motion robot 1 13, orbiter 1 10, disk polish heads 1 12 and is used to move these components horizontally to accomplish transport of the disks between the disk flip and rinse station 106 and polish platen 1 16 at position P (FIG. 1C). The main gantry robot 108 comprises a gantry body 401, a gantry drive screw assembly 404 and a pair of gantry drive tracks 405.

The gantry drive screw assembly 404 moves the gantry body 401 along its axis and the gantry drive tracks 405. During polishing it is important to minimize the transfer of motion throughout the substrate polishing apparatus 100. Any such motion may cause polish disk heads 1 12 to move in a non-circular orbit which causes unequal velocity vectors across the disk surface and non-uniform polishing. Therefore, the main gantry robot 108 further

5 comprises a gantry table brake 406 (See Fig. IB) or an alternative motion restraint apparatus 408 which are used to reduce the transfer of any motion throughout the substrate polishing apparatus 100.

FIG. 4B shows the gantry table brake 406 which is used to provide a mechanical lock for the main gantry robot 108 during polishing to avoid reflection of the

10 polish force back into the gantry drive screw assembly 404 and to ensure that play in the screw assembly does not affect polish precision. The gantry table brake 406 comprises a brake arm body 410 attached to the main gantry robot 108, a brake arm 412 attached to the brake arm body 410 and a clamp assembly 414 which is attached to the frame 126. The clamp assembly 414 further comprises a clamp assembly body 416, a diaphragm 418, a

15 brake piston 420, a brake shoe 422, a brake flexure 424 and a clamp plate 426. In operation, the brake arm 412 moves into the brake arm cavity 428 formed between the flexure 424 and the clamp plate 426 as the main gantry robot 108 moves into position for polishing. Once in position, air is used to pressurize the air pressure cavity 430 formed between the clamp assembly body 416 and the diaphragm 418. The air pressure acts to move the brake piston

20 420 which in turn moves the brake shoe 422 and the brake flexure 424 toward the clamp plate. The brake flexure 424 forces the brake arm 412 against the clamp plate 426 thereby locking the main gantry robot 108 to the frame 126. Air is supplied to activate the brake from the main air system, controlled by an air valve such as valve 440 shown in FIG. 4C in response to computer control 120.

25 FIG. 4C shows motion restraint apparatus 408 which alternatively may be used to reduce any motion of the main gantry robot along its axis of movement caused by the torsional energy created during polishing. The motion restraint apparatus 408 comprises an air brake cylinder 432 which applies a force to the main gantry motion restraint arms 434. In a preferred mode, a pair of air brakes 432 and used on each side of the main gantry robot

30 108. The air brake cylinders are controlled by the computer control system 120.

FIG. 5A shows the orbiter vertical motion robot 1 13 which is used to move the orbiter 1 10 and the disk polish heads 1 12 in a vertical direction. (Disk polish heads 1 12 are mounted on supporting columns 730 as described below.) This motion allows the disk polish heads to retrieve the disks from the hydrodynamic substrate presenter mechanisms 5 316, to lower and lift the disks relative to the polish platen 1 16, to lower and lift the disks relative to the disk rinse compartment 306 and to lower the disks onto the hydrodynamic substrate holder mechanisms 336. The orbiter vertical motion robot 113 comprises a vertical drive screw assembly 502 mounted on an orbiter vertical motion robot support 504. Vertical drive screw assembly 502 utilizes a lead screw mechanism in a known manner to vertically position orbiter mounting plate 506 which carries orbiter 1 10. Orbiter mounting plate 506 moves vertically upward and downward along a pair of orbiter vertical motion tracks 508. Orbiter 110 imparts a circular motion to a plurality of disk polish heads 112 without allowing each disk polish head 112 to rotate about its own axis. This circular orbit provides the same velocity vector at each point on the surface of the disk, and therefore, provides for a uniform polish across the disk surface.

As best seen in FIG. 5B, orbiter 1 10 is driven by motor 510 via a belt drive mechanism. Belt 512 transmits torque from the motor shaft to orbiter rotation shaft 514. Orbiter rotation shaft 514 is fixed to orbiter rotation support 516, which carries counter weight 518. Orbiter eccentric shaft 520 is mounted on bearings 522 within support 516 so that it may rotate with respect to the support. At the lower end of eccentric shaft 520 is fixedly attached solid connector bar 508, which carries polish head 1 12. Cover 515 surrounds the lower end of shaft 520 and the top of bar 508 to protect the parts from slurry in the polishing process. At the top of eccentric shaft 520 an anti-rotation mechanism comprising linkage bar 524 and belt drive 526 prevent rotation of the orbiter eccentric shaft about its own axis as it is rotated about the axis of rotation shaft 514. Linkage bar is fixed to eccentric shaft 520 at point 528. Toothed pulley 530 is mounted on shaft 514, but has a hole through which shaft 520 freely passes. Belt drive 526 causes toothed pulley 532 on shaft 534 to rotate in sync with rotation shaft 514. Fixed on pulley 532 is shaft 536. Linkage bar 524 is mounted on shaft 536 via rotatable connection 538. It will be appreciated by those skilled in the art that this arrangement permits orbiter eccentric shaft 520 to follow a circular path around the axis of shaft 514, but with out rotating about its own axis. Home position sensor 540 communicates with computer control 120 in order to detect presence at a predetermined home position. Motor 510 also preferably includes an encoder which continually provides position and velocity information to control 120 in an known manner.

FIG. 6 illustrates an alternative embodiment of orbiter 1 10a which is also designed to polish multiple substrates simultaneously. The orbiter 1 10a comprises an orbiter shaft 602 which is attached to a orbiter rotation gear 604 which is belt-driven by a spindle motion motor 606. It should be appreciated that the orbiter shaft 602 is not connected to the center of orbiter rotation gear 604 so that rotation of the orbiter shaft 602 produces an eccentric orbit. The lower end of the orbiter shaft 602 is fixedly connected to a solid connector bar 608 which is connected to a plurality of disk polish heads 1 12.

The upper end of the orbiter shaft 602 is fixedly connected to anti-rotation mechanism 610 which prevents rotation of the orbiter shaft 602 about its own axis. The top

5 of the orbiter shaft 602 is fixedly attached to a horizontal and longitudinally grooved fitting 612 which receives a single rod 614 which itself is fixedly attached to the bottom of one end of the anti-rotation mechanism 610. The single rod 614 is capable of sliding within, and along the longitudinal axis of, the grooved fitting 612 during rotation of the orbiter shaft 602. Two parallel, horizontal and longitudinally grooved fittings 616 are fixedly attached to

10 the bottom of the opposite end of the anti-rotation mechanism 610 in a position normal to the grooved fitting 612 on the orbiter shaft 602. These two grooved fittings 616 receive two parallel rods 618 which are capable of sliding within, and along the longitudinal axis of. the two grooved fittings 616 upon rotation of the orbiter shaft 602. The two parallel rods 618 are fixedly attached to the orbiter mounting plate 506. An orbiter cover 620 covers the

15 orbiter 110a components and acts to reduce slurry contamination of the orbiter 1 10a and to reduce contamination of the polishing process by grease used in the orbiter 1 10a.

In operation, the spindle motion motor 606 turns the orbiter rotation gear 604 thereby moving the orbiter shaft 602 in an eccentric orbit. The orbiter shaft 602 thereby moves the solid connector bar 608 and the disk polish heads 1 12 in a circular motion. The

20 anti-rotation mechanism 610 moves in a horizontal, back and forth motion in a direction parallel to the two parallel rods 618 which prevents the rotation of the orbiter shaft 502 about is own axis. As a result, the solid connector bar 608 and the disk polish heads 1 12 move in a circular orbit. The solid connector bar 608 does not spin about its own axis, since it is fixedly attached to the orbiter shaft 602. The disk polish heads 112 are also prevented

25 from rotating about their own axis as described below.

In a further alternative embodiment, one orbiter per disk polish head is used to minimize the impact of polishing on movement of the web tape 1 15. When the orbiter operates with four disk polish heads 1 12, all of the disk polish heads 1 12 move in the same direction during polishing, and the resulting in substantial torque being applied to web tape

30 115 during polishing. The torque acting on the tape can be reduced by using one orbiter per disk polish head and multiple orbiters. This allows independent control over the direction of the orbit for each disk polish head. Therefore, by appropriately choosing the direction of the orbit for each disk polish head, e.g., by using opposing orbits for adjacent disk polish heads, the net torque on the web tape can be reduced.

35 The disk polish heads 1 12 are designed to individually (i) retrieve, hold and release a disk, (ii) retain a single disk during polishing, (iii) transfer the requisite pressure to the disk during polishing and (iv) absorb the impact of any changes in the web tape surface 115 during polishing to avoid the phenomenon of dub-off whereby the edge of the disk is

5 eroded due to its impact against the web tape during polishing.

FIG. 7A shows a cross-sectional view of a preferred embodiment of disk polish head 112 which provides the above functions and is relatively small and lightweight. This embodiment also provides for simultaneous polishing of multiple disks of various thicknesses to different polish parameters. The primary components of the disk polish head

10 112 are a seal plate 702, a disk plate 704. a plastic retainer ring 706, a metal ring disk carrier 708, three disk polish head diaphragm pistons 710 and the elliptical differential radius bearing 712. Seal plate 702 forms a cover around disk plate 704 and is generally circular in construction having a depression in the center for receipt of the elliptical differential radius bearing 712. The metal ring disk carrier 708 comprises a metal ring having the same outside

15 diameter as the seal plate 702 and an inside diameter that is slightly larger than the disk to be polished. The metal ring disk carrier 708 is fixedly attached to the bottom of the seal plate 702. The plastic retainer ring 706 also comprises a ring having a pre-determined inside diameter and an outside diameter that is approximately of the same proportion as the outside diameter of the metal ring disk carrier 708. The plastic retainer ring 706 preferably has

20 strong magnets secured to it so it may be magnetically attached to the bottom of the metal ring disk carrier 708. It should be appreciated that the use of a magnetically attached plastic retainer ring allows for ease of replacement compared to, for example, a bolted or screwed plastic retainer ring.

The disk plate 704 is suspended from the bottom of the seal plate 702 by a

25 disk plate flexure 711 and the three disk polish head diaphragm pistons 710. The disk plate 704 fits inside the metal ring disk carrier 708 and the plastic retainer ring 706. The disk polish head diaphragm pistons 710 operate to independently apply pressure to the disk plate 704. This is accomplished by using air pressure applied through cavity 710a to diaphragm 710b to exert force on disk plate flexure 71 1 through piston head 710c, spacer 710d and

30 backup ring 710e. Diaphragm 710b is supported by ring 71 Of and the piston assembly is secured by screw 710g, which passes through flexure 71 1 into disk plate 704.

The disk plate flexure 71 1 is a partly spiral, serpentine ring which is sufficiently stiff to provide lateral stability as the disk polish head gimbles. Specifically, flexure 711 allows polish head 1 12 to move in the vertical direction while restricting its

35 movement in the horizontal direction. The thickness of the disk plate 704 is less than the combined thicknesses of the metal ring disk carrier 708 and plastic retainer ring 706 such that a cavity exists between the bottom of the disk plate 704 and the web tape 1 15 when the plastic retainer ring 706 engages web tape 1 15. Therefore, the disk fits within this cavity and within the inside diameters of the metal ring disk carrier 708 and plastic retainer ring 706. It should be appreciated that the inside diameter of this cavity is sized such that the disk fits loosely within the cavity. This allows the disk to move during polishing or to precess.

FIG. 7B shows the disk plate flexure 71 1. The disk plate flexure 71 1 is a spiral, serpentine ring which is stiff and, therefore, provides stability as the disk polish head gimbles. Specifically, the disk plate flexure 71 1 allows the disk polish head 1 12 to move in the vertical direction while restricting its movement in the horizontal direction.

Polish head 1 12 is secured to supporting column 730 by elliptical differential radius bearing 712. Bearing 712 is designed to allow disk polish head 1 12 to gimble or float to absorb any changes in the web tape surface during polishing and to prevent it from rotating about its axis. Gimbles are typically spherical in shape and require the use of pins to avoid rotation; however, the elliptical shape of the elliptical differential radius bearing 712 inherently prevents such rotation and provides for an un-biased contact point. Specifically, the elliptical differential radius bearing 712 is seated in a corresponding elliptical shaped cup 714 secured to seal plate 702 by support fixture 715 such that the seal plate 702 is prevented from moving in a horizontal plane about its own axis due to contact between the mating elliptical surfaces. It should be appreciated, however, that, if desired, the disk polish head may be designed to allow for rotation about its own axis. Specifically, the design may allow for free rotation about its own axis or for precessing.

FIG. 8 shows elliptical differential radius bearing 712 in more detail. As noted, elliptical shaped cup 714 is seated in depression seal plate 702. It should be appreciated that the use of such an arrangement allows the gimble to be as close as possible to the polishing surface to avoid the creation of a moment not parallel to the polishing surface. The creation of such a non-parallel moment may case a phenomenon known as "nose diving" which is essentially uneven contact between the edge of the disk and the platen as the polish head moves resulting in non-uniform polishing. A bearing retainer 804 is placed over the elliptical differential radius bearing 712 to secure it in place. The elliptical differential radius bearing 712 has a vertically extending cylinder which extends pass the bearing retainer 804 and is connected to a bearing shaft 806.

Referring back to FIG. 7, the connection of a single disk polish head 1 12 to solid connector bar 508 via support column 730 is shown. The seal plate 702 is attached to the bottom of the connector bar shaft 716 by a bayonet mount 718 which is secured in place by turning it 60 degrees. It should be appreciated, however, that the bayonet mount 718 is a loose connection so that the disk polish head 1 12 is free to gimble during polishing and there is minimal contact between the top and bottom of the bayonet mount 718. The connector bar shaft 716 is connected to the bottom of the solid connector bar 508 such that downward pressure may be exerted on the disk polish head 112 by the downward movement of the orbiter 1 10. The bearing shaft 806 is connected to column piston 720 which applies additional and separately controlled pressure to disk polish head 112. Column piston 720 comprises diaphragm 732 secured at its periphery 734 to shaft 716 and in the center to piston head 736. Piston head 736 is secured to bearing shaft 806 via screw 738. Guide pin(s) 740 carry torquing loads. A linear voltage displacement transducer 722 is used in conjunction with the computer control system 120 to control the movement of the orbiter vertical motion robot 1 13 by measuring the distance between the bottom of the disk polish head 1 12 and the polish platen 1 16. In operation, the orbiter vertical motion robot 1 13 lowers the disk polish heads 1 12 holding disks onto the polish platen 116 during which time polishing slurry is injected onto the wet tape 1 15 in the required amount and directly under the disks. The requisite pressure is applied by controlling the pressure exerted by the connector bar shaft 716, the column piston 720 and the resulting pressure exerted by the bearing shaft 806 on the seal plate 702 and by controlling the three disk polish head diaphragm pistons 710 and the resulting pressure exerted on the disk plate 704.

FIG. 9 shows a calibration fixture 900 to determine the requisite pressure to be applied to the disk during polishing using a calibration procedure, specific to the disk polish head design to be used. Calibration fixture 900 comprises a calibration base 902 upon which four gage heads 904 are mounted. Each gage head 904 comprises a circular table 906 mounted on the calibration base 902 using air bearings. Mounted on top of each circular table 906 are three disk loadcell sensors 910 and three ring loadcell sensors 911. Three ring loadcell sensors 910 are positioned under a calibration ring 912 which has approximately the same circumference as the metal ring disk carrier and the plastic retainer ring of the disk polish head to be used. The three disk loadcell sensors 91 1 are positioned under a calibration disk 914 which is approximately the same circumference as the disk to be polished or as the disk plate of the disk polish head to be used.

In operation, the entire calibration fixture 900 is placed on the polish platen 1 16 and the disk polish heads are lowered on top of each corresponding set of calibration rings 912 and calibration disks 914. The metal and plastic ring disk carriers align with the calibration ring 912 and the disk plate aligns with the calibration disk 914. Therefore, the force exerted on the calibration ring 912 can be measured separately from that exerted on the calibration disk 914. A given setpoint pressure is then applied to the disk polish heads, specifically to the metal and plastic ring disk carriers and to the disk plate and measurements are taken based upon the output from the loadcell sensors 910, 911. These measurements are used in an equation that correlates the setpoint pressures with the forces measured by the loadcell sensors 910, 91 1 as explained below. The computer control system 120 then uses these equations to control the pressure exerted on the disk plate and the metal and plastic ring disk carriers during actual polishing. In a preferred embodiment, tables 906 float on air bearings (not shown) to improve the accuracy of data by preventing a change in the strain in the table during measurement.

FIG. 10 shows an alternative embodiment of a disk polish head. In this embodiment, a disk plate 1002 is fixedly attached to seal plate 1004. A metal ring disk carrier 1006 and a plastic retainer ring 1008 are attached to the seal plate 1004 by a disk plate flexure 1009 and three diaphragm pistons 1010. These diaphragm pistons 1010 operate in the same manner as in the preferred embodiment; however, in this alternative embodiment, the pressure on the metal ring disk carrier 1006 and the plastic retainer ring 1008 is separately controlled, as opposed to the pressure on the disk plate 1002. Other alternative embodiments include fixedly attaching both the disk plate and the carrier rings to the seal plate such that there is no separate pressure control on either and having diaphragm pistons on both the disk plate and the metal and plastic rings to provide for separate control of each.

FIG. 1 1 shows a partial cross-sectional view of yet another embodiment of a disk polish head. This embodiment is designed to more predictably control the movement of the disk within the confines of the metal ring disk carriers and the plastic retainer rings during polishing. This is accomplished using an air bearing disk plate 1102, attached to the bottom of a disk plate 1 106, which is preferably flat and has a surface height variance of not more than approximately 0.00005 inches. On the bottom of the air bearing disk plate 1102 is a carrier film 1104, selected from various compressible materials such a polyurethane, against which the disk D frictionallv adheres during polishing such that the disk D rotates with the air bearing disk plate 1 102. In addition, central member 1 1 1 1 is attached to the air bearing plate 1 102 and extends into the center hole of the disk D to retain the disk. The air bearing disk plate 1 102 is supported under disk plate 1 106 by air bearings 1 1 16 which allow the air bearing disk plate 1 102 to rotate. The outer perimeter of the air bearing 1 1 16 is a compliant material that meters the escape of air thereby maintaining the back pressure between the disk plate 1 106 and the air bearing plate 1 102. The compliance of the outer perimeter of the air bearing 1 1 16 allows the disk plate 1 106 and the air bearing plate 1 102 to be non-parallel and still maintain the integrity of the air bearing 1 1 16. The air bearing disk plate 1 102 is also attached to the disk plate 1 106 by a stud 1108 having a circular base 1 112 and a cylindrical extension 1 1 14. The cylindrical extension is rotatably retained in the bottom of the disk plate 1 106. The stud 1 108 has a plastic stud bearing 1 110 of known frictional properties which acts to permit controlled rotation of the air bearing disk plate 1102 and limit its eccentric motion. The stud 1 108 also acts to retain the rotating plate 1102 when the disk polish head 1 12 is not in contact with the polish platen 116. By using both the air bearings 1116 and an appropriately designed plastic stud bearing 1110, the rotation of the air bearing disk plate 1 102 is more predictably controlled. If desired, a hydraulic or air disk pickup system as described below may be incorporated into disk plate 1102.

It should be appreciated that an objective of the present invention is to avoid non-uniform polishing or the formation of patterns on the surface of the disk during polishing in order to provide improved disk characteristics. This is preferably accomplished according to the invention, as described in connection with the preferred embodiments, by preventing or substantially preventing the disk from rotating about itself during polishing. However, a disk polish head also may be designed according the present invention to allow for free rotation or precessing of the disk about its own axis to provide uniform velocity profiles across the surface of the disk and thus similar improved disk surface characteristics. FIG. 12 shows yet another preferred embodiment of the disk polish head 112 which includes the ability to introduce slurry onto the web tape 115 through the disk polish head 1 12 and through the center of the disk, taking advantage of the disk center hole. During polishing, the polish slurry is moved to the outside of the circular orbit and less slurry becomes available for polishing. FIG. 12 shows a disk plate 1202 which has a slurry bore 1204 which is positioned above the center of a disk 1206. A slurry line 1208 extends from a source of slurry 1210 and terminates within or under the slurry bore 1204. In operation, a computer controlled pump may be used to pump slurry immediately before, or during, polishing through the slurry line 1208 and place slurry onto the web tape 115 and underneath the disk plate 1202 and the disk 1206. The continuous addition of slurry in such a controlled fashion enhances efficient placement of the polishing slurry relative to the disk and enables additional slurry to be used as necessary during polishing.

As noted above, the disk polish head 1 12 must be capable of lifting and releasing a disk. Furthermore, such functions must be robust and precisely monitored. One method for accomplishing this lifting and releasing is by the use of air pressure and vacuum, respectively (described below): however, such method may result in slurry accumulation in the air line resulting in corrosion or pluggage of the line. A preferred embodiment avoids this problem by using positive and negative water pressure and a water film on the disk plate 704 for lifting and releasing a disk, respectively. FIG. 13 schematically illustrates a system for lifting and releasing a disk according to a preferred embodiment. Water lines 1302 are provided to each disk polish head 112. The water lines mate with a disk pickup manifold system in each disk polish head 112, described below in connection with FIG. 14, which permits a liquid film to be applied to the bottom of the disk plate 704 and controlled via negative and positive pressure. Water lines 1302 are supplied with pressurized deionized water by inlet water line 1305 which is controlled by an inlet water valve 1306 and a mixing manifold 1308. Pressurized air is supplied by air inlet line 1310 and is controlled by an air inlet valve 1312 and mixing manifold 1308. Optionally, an air regulator 1314 may be used to control the air pressure. The mixing manifold 1308 is used to supply water or air to water lines 1302. The inlet water line 1305 is connected by a tee fitting (not shown) at a position 1316 to a waste line 1318 which flows through a negative pressure peristaltic pump 1304 and through an outlet valve 1320 to the deionized water system 122. The tee fitting allows water to flow to both the waste line 1318 and through the mixing manifold 1308 to the water lines 1302. A pressure sensor 1322 is located on each water line 1302 to provide a measure to the computer system 120 of the water or air pressure in each water line 1302 for each disk polish head 1 12. The operation of this system to lift and release a disk is described below in connection with FIG. 32 and 33!

FIG. 14 shows a cross-sectional view of a disk polish head 1402 and a disk pickup manifold system for use with a system for lifting and releasing a disk such as the one illustrated in FIG. 13. The disk pickup manifold system is designed to lift and release a disk utilizing fluid pressure and comprises a ring-shaped manifold 1404 which is positioned between a seal plate 1413 and a disk plate 1405. The disk plate 1405 has a plurality of disk plate holes 1406 which open on the bottom of the disk plate 1405. The plurality of disk plate holes 1406 are connected to a main disk plate cavity 1408 which is connected to a main seal plate cavity 1414. O-rings 1410 are used to seal the main disk plate cavity 1408 and the main seal plate cavity 1414. The main seal plate cavity 1414 is connected to a fluid line 1416 which is placed under positive or negative pressure.

In operation, the fluid line 1416, the main seal plate cavity and the main disk plate cavity are filled with a fluid. Negative pressure is applied to the fluid in the fluid line 1416 which sucks a disk against the bottom of the disk plate 1405. To release the disk, positive pressure is applied to the fluid in the fluid line 1416 which pushes the disk away from the bottom of the disk plate 1405. In a preferred embodiment the fluid used is water; however, air may also be used.

Magazine

FIGS. 16A and 16B show magazine 1 14. Magazine 1 14 supplies web tape 1 15 which is fed over polish platen 1 16 upon which polishing occurs. The magazine automatically feeds web tape 1 15 from supply roller 1602 containing web tape 115, across polish platen 1 16 for polishing and to take-up roller 1604. Web tape 1 15 moves across polish platen 1 16 in conjunction with two idler rollers 1600. The tension of the web tape 1 15 is controlled by the tension roller 1609 which is capable of moving its axis of rotation to tighten or loosen web tape 115.

Further, the magazine retracts web tape 1 15 for conditioning after each polish cycle. Conditioning comprises spraying web tape 1 15 with water using spray nozzles 1601 and moving web tape 115 across a conditioning roller 1603 and a brush roller 1605 which act to refurbish the surface or nap of web tape 1 15 material. It should be appreciated that brush roller 1605 is capable of moving its axis of rotation closer to or away from web tape 1 15 depending upon the amount of brushing desired. After conditioning, web tape 1 15 is fed back over polish platen 1 16 in a manner such that a small portion of new web tape 1 15 is now on polish platen 116. The slight advance of web tape 1 15 after each polish cycle ensures that the tape is slowly, but continuously renewed in order to avoid long-term decay in its polishing performance. The magazine also acts to pre-condition this new portion of web tape 115 before use. Supply roller 1602 containing web tape 115 is easily removed when empty and replaced. Similarly, take-up roller 1604 is easily removed when full of used web tape 1 15. The general operation of magazine 1 14 is described in greater detail in co-pending Application Serial No.08/833,278, filed April 4, 1997, entitled "Polishing Media Magazine for Improved Polishing", which is incorporated herein by reference thereto.

Various embodiments of the conditioning roller for conditioning the web tape can be employed, including a diamond conditioning roller and a nickel composite conditioning roller. Typically, the diamond conditioning roller is employed for web tapes that are more rigid and used to perform the initial high stock removal/planarization step of a multiple step polish process. The nickel composite conditioning roller is typically employed for web tapes that are soft and used to perform the final lower stock removal surface finish steps of a multiple step polish process. FIG. 16C shows one embodiment of a conditioning roller which is a diamond conditioning roller 1607 consisting of two sleeves 1608 secured to a central shaft 1610 with bolts (not shown). Sheets of metal 1612, 1614, 1616, 1618 are attached using adhesive to each of the two sleeves 1608; however the sheets of metal 1612, 1614, 1616, 1618 do not cover the entire circumference such that two opposed gaps 1619 exist along the axis of the conditioning roller 1608. The sheets of metal 1612, 1614, 1616, 1618 are partially coated with a diamond abrasive material. The positions where the adjacent sheets of metal 1612, 1614, 1616, 1618 are joined together on the sleeves 1608 are located to correspond to the area between the locations where adjacent disks are polished on polishing platen 116 and web tape 1 15. The orientation of the metal sheets 1612, 1614, 1616, 1618 is such that upon rotation of the conditioning roller 1607 the web tape is forced toward to outside of the conditioning roller. The conditioning roller 1607 is designed to be driven against the web tape so that the leading edge of each conditioning roller half is the edge where the stripes of abrasive material meet in a point at the center of the conditioning roller 1607. The intensity of conditioning imparted onto the surface of the web tape can be adjusted by altering the nominal size of the diamond abrasive particles, the fraction of the conditioning roller surface area covered by abrasive particles and the height and shape of the embossing pattern.

FIG. 16D shows a pian view from the top of the metal sheets 1612, 1614, 1616, 1618 and the abrasive coated areas 1622 on the metal sheets 1612, 1614, 1616, 1618. This pattern increases the intensity of contact between the conditioning roller 1607 and the web tape.

FIG. 16E shows an elevational view of the metal sheets 1612, 1614, 1616, 1618 and the abrasive coated areas 1622 on the metal sheets 1612, 1614, 1616, 1618.

The nickel composite conditioning roller (not shown) similarly consists of a hollow roller which has been cut into two halves which can be secured to a central shaft with bolts which are recessed below the roller surface. In the case of the nickel composite conditioning roller, the metal halves are plated with nickel phosphorous or other appropriate metal tailored for the specific polishing process being performed.

In operation, the magazine incrementally advances the web tape such that a new section of web tape is advanced onto the polish platen before each polishing step, preconditions this new section of web tape before use and conditions that portion of the web tape already being used. This is accomplished by a sequence of four steps which occurs immediately prior to each polishing step. Each time this sequence occurs a small amount of new pre-conditioned web tape is incrementally advanced onto the polishing area on the polish platen to replace an equal amount of material which has been polished on many times and which is removed from the polishing area of the polish platen. This continual incremental replenishment of the web tape allows the polishing process to be performed in a controlled, uninterrupted steady-state manner so that the surface of the web tape is exactly the same for an extended period of time (limited only be the actual length of the roll of web tape).

In the first step of this sequence, the web tape 1 15 is retracted (moved in the direction of the supply roller 1602) by a distance of M, which is determined by the extent to which pre-conditioning of the web tape 1 15 is desired. While this movement is taking place, the conditioning roller is being driven in the same direction as the web tape 115 with a surface linear velocity which is also determined by the desired extent of pre-conditioning of the web tape 115. In this step, the length of web tape 115, M,, is abraded by the surface of the conditioning roller in a controlled manner to remove the less dense outer layer of the web tape 1 15 and to create a structured surface on the web tape 15 which retains polishing slurry in the dense, rigid microscopic protrusions of the web tape 115 which contact the disk surface during the polishing operation. The functional properties of the pre-conditioned web tape are determined by controlling the web tape tension, the web tape linear speed, the conditioning roller linear speed, the conditioning roller abrasive size, the conditioning roller embossed pattern, the proportion of the conditioning roller which is covered with abrasive and the distance by which the web tape is incrementally advanced for each polishing cycle. It should be appreciated that the nickel composite conditioning roller is typically used with non-abrasive slurry and, therefore, does not abrade the web tape as the diamond conditioning roller does, but instead works the non-abrasive slurry into the pores of the web tape. Therefore, for the nickel composite conditioning roller, there is a slurry manifold to dispense non-abrasive slurry at the conditioning roller/web tape interface, and the amount of non-abrasive slurry dispensed is an additional control attribute for the nickel composite conditioning roller.

In the second step of the sequence, the web tape 1 15 is advanced (i.e., moved in the direction of the take-up roller 1604) by a distance M₂ during which the web tape 115 is brushed by the brush roller and sprayed with deionized water to remove any accumulation of polishing glaze consisting of agglomerated slurry and disk substrate material that may be fused onto the surface of the web tape. A squeegee is forced against the web tape 115 during this step to remove excess water from the web tape 115 as it is advanced onto the polishing platen. The conditioning roller moves at the same linear velocity as the web tape 115 during this step so that no relative motion occurs between the surface of the conditioning roller and the surface of the web tape 1 15. The cleaning of the web tape is controlled by the speed which the web tape moves, the speed and force applied to the brush roller, the pressure with which the water is flowing against the web tape and the force applied to the squeegee.

The third step in the sequence occurs when the slurry is applied to the web tape on top of the polish platen 1 16. For this step the web tape 1 15 does not move and the squeegee is forced against the web tape 115. The slurry dispense valves located on the squeegee are opened for a controlled time duration allowing the slurry to flow out onto the web tape. This forms separate, isolated pools of slurry on the web tape for each of the disk polish heads 1 12. It should be appreciated that slurry dispense valves may not be used, or could be used in combination with, the introduction of slurry through the disk polish head 112.

In the fourth step of the sequence, the web tape is advanced (i.e.. moved in the direction of the take-up roller 1604) a distance M, which moves the pools of slurry that were deposited on the web tape 1 15 to the position on the polish platen 1 16 where the disk polish head 1 12 are lowered into place to begin the polishing operation. The conditioning roller moves at the same linear velocity as the web tape during this step so that no relative motion occurs between the surface of the conditioning roller and the surface of the web tape 115.

For the web tape to be continually replenished on a steady-state basis it is necessary for the sum of distances M₂ and M₃ to be larger than the distance M,. The amount of web tape which is incrementally advanced for each polish cycle equals the difference (M₂ + M₃) - Mi. The rate (in polishing cycles) at which the polishing material is completely replenished on an ongoing basis is represented by the ratio ((M₂ + M₃) - M,)/M,. It should be appreciated that for a diamond conditioning roller pre-conditioning a new section of web tape on a first-time basis, the magazine sequence is performed repeatedly without applying slurry or polishing a disk until the number of cycles determined by the replenishing rate have been performed. Alternatively, this can be accomplished using a reduced number of cycles (at least one) with a correspondingly more intensive application of web speed, conditioning roller speed and web tension so that the same extent of conditioning can be imparted to the surface of the web tape.

The polish platen 116 is a flat plate secured to the magazine 114 and the frame 126. The web tape 1 15 lies on top of the polish platen 1 16 and the disk polish heads act to polish the disks on the web tape 1 15. Therefore, during polishing heat is generated by the friction between the disk and the web tape 115. As a result, the polish platenl 16 will increase in temperature. In addition, during non-polishing periods, the polish platen 116 may decrease in temperature. It is desirable to maintain the temperature of the polish platen 116 to avoid introducing temperature effects into the quality of the polish. Therefore, a system for controlling the temperature of the polish platen 1 16 is needed.

FIG. 16E shows the polish platen 116 from the bottom. The bottom of the polish platen 1 16 is made to receive an electrical heating element 1624 which traverses the perimeter and interior of the polish platen 1 16. The bottom of the polish platen 1 16 is also made to receive four cooling disks 1626 in positions which generally correspond to the areas where polishing will occur on the top of the polish platen 116. Each of these cooling disks 1626 have a water inlet 1628 and a water outlet 1630. The water inlet 1628 and the water outlet 1630 are connected by a grooved path (not shown) which travels through each cooling disk 1626. Alternatively, the water inlet 1628 and the water outlet 1630 may be connected by tubing which may be in coiled arrangement.

In operation, thermocouples (not shown) are mounted to certain points on the bottom of the polish platen 1 16. When the temperature increases above a given setpoint, cooling water is pumped through each of the cooling disks 1626. When the temperature decreases above a given setpoint. the electrical heater 1624 is operated to increase the temperature of the polish platen 1 16. Of course other methods known in the art for heating and cooling may be used.

Computer Control

FIG. 17 illustrates an overall control system 120 for achieving control of the substrate polishing apparatus 10D. Control system 120 comprises a central processing unit 1702 for providing centralized control of the substrate polishing apparatus 100. Although central processing unit 1702 is shown in FIG. 17 as a personal computer, it is to be appreciated that central processing unit 1702 may comprise a single or multiple computing machines, together with data storage devices such as hard drives (not shown), monitor displays, input means such as keyboards, and data communications equipment such as modems or ethernet cards (not shown).

Control system 120 further comprises a controller circuit 1704 coupled to central processing unit 1702. Generally speaking, controller circuit 1704 comprises a plurality of controller cards that are capable of receiving commands from the central processing unit 1702 and converting these commands into output signals that drive physical devices such as stepper motors, pumps, and valves. Controller circuit 1704 is coupled to each of a plurality of mechanical subsystems described previously, including main gantry robot 108, orbiter 110, magazine 1 14, disk flip and rinse station 106, dry conveyor 102, wet conveyor 1 18, and cassette/disk handling robot 104, as well as other subsystems including a safety /emergency operation subsystem 1706. and an operator control panel 1708. It is to be appreciated that the main gantry robot 108. orbiter 1 10, magazine 1 14, disk flip and rinse station 106, dry conveyor 102, wet conveyor 1 18, and cassette/disk handling robot 104 are included as simple boxes in FIG. 17 for simplicity and clarity of disclosure, and comprise physical elements described elsewhere in this disclosure. For purposes of describing the control system 120, a person skilled in the art will recognize that main gantry robot 108, orbiter 1 10, magazine 114, disk flip and rinse station 106, dry conveyor 102, wet conveyor 118, cassette/disk handling robot 104, safety/emergency operation subsystem 1706, and operator control panel 1708 comprise motors, valves, or pumps as necessary to effectuate commands received from controller circuit 1704 and to achieve the mechanical or hydraulic result specified previously in this disclosure. Although individual, separate connections between the controller circuit 1704 and the subsystems is shown in FIG. 17, it is to be appreciated that connectivity can be achieved using a distributed multiplexed I/O system offered by suppliers such as National Instruments. A person skilled in the art will be able to recognize that the specific motors, valves, and pumps, as well as their associated controller cards, can be obtained as off the shelf products from manufacturers such as National Instruments, and that a description of the characteristics and functionality of the respective mechanical subsystems as provided in the present disclosure would enable assembly and use by a person skilled in the art.

Control system 120 further comprises a data acquisition assembly 1710 designed to receive signals from^" optical and/or mechanical transducers or sensors associated with main gantry robot 108, orbiter 110, magazine 1 14, disk flip and rinse station 106, dry conveyor 102, wet conveyor 118, cassette/disk handling robot 104, safety/emergency operation subsystem 1706, and operator control panel 1708. As shown in FIG. 17, data acquisition assembly 1710 is coupled to central processing unit 1702 and is designed to convert these signals into data readable by the central processing unit 1702, so that software programmed into central processing unit 1702 is capable of receiving feedback and the current state of the mechanical subsystems of substrate polishing apparatus 100. Generally speaking, data acquisition assembly 1710 comprises a plurality of data acquisition cards capable of receiving mechanical, optical, electrical, or temperature signals from various transducers or sensors on the various mechanical subsystems, and can also can be obtained as off the shelf products from manufacturers such as National Instruments. A person skilled in the art will be able to recognize that the specific sensor or transducer, as well as their associated data acquisition cards, can be obtained as off the shelf products and that a description of their characteristics and functionality as provided in the present disclosure would enable assembly and use by a person skilled in the art. Finally, although individual, separate connections between data acquisition assembly 1710 and the subsystems is shown in FIG. 17, it is to be appreciated that connectivity can be achieved using a distributed multiplexed I/O system.

Control system 120 further comprises a data link 1712 for coupling the central processing unit 1702 to a corporate data network, shown as element 1714 in FIG. 17. Data link 1712 may comprise, for example, an ethernet card if corporate data network 1714 is an ETHERNET network. Using this network connection, calibration may be performed using measurements from the portable calibrator fixture 900 that is also attached to the corporate network, the measurements being transferred from the portable calibrator fixture 900 through the corporate data network 1714 to the control system 120. In this manner, the same portable calibrator 900 may be used to calibrate the disk polish heads 1 12 on several different substrate polishing apparatuses purchased by the same company, therefore reducing overall cost.

According to a preferred embodiment, control system 120 uses a modular, event-oriented control strategy to separately control each of the mechanical subsystems of the disk polishing apparatus 100, that is, main gantry robot 108, orbiter 110, magazine 114, disk flip and rinse station 106, dry conveyor 102, wet conveyor 118, cassette/disk handling robot 104, safety/emergency operation subsystem 1706. and operator control panel 1708. Generally speaking, the control strategy is modular in that control software is comprised of separate software modules, each module corresponding to a separate mechanical subsystem of the substrate polishing apparatus 100. Generally speaking, the control strategy is event- oriented in that each software module runs its associated mechanical subsystem separately from other software modules, interacting with other software modules through a set of shared variables or global handshakes that are modified or instantiated as physical events take place in the associated mechanical subsystems.

It has been found that such use of a modular, event-oriented control strategy to control a disk polishing apparatus advantageously provides for ease of module design, module programming, and module debugging. It has further been found that such use of a modular, event-oriented control strategy to control a disk polishing apparatus advantageously provides for a simplified, easy to use operator interface and subsystem testing interface for use by operators and/or maintenance engineers. Finally, it has been found that such use of a modular, event-oriented control strategy to control a disk polishing apparatus advantageously provides for easy updating or changing of process parameters or recipes by the operators and/or maintenance engineers.

FIG. 18 shows a block diagram of software program 1800 loaded in central processing unit 1702 that is executed during an AUTORUN mode representing the steady state production operation of the substrate polishing machine 100. In a preferred embodiment, the software is designed to run on a Windows platform and uses the BridgeView G-programming language from National Instruments. According to a preferred embodiment, software program 1800 comprises a module 1802 for controlling the main gantry robot 108, a module 1804 for controlling orbiter 110, a module 1806 for controlling the disk flip and rinse station 106, a module 1808 for controlling dry conveyor 102, a module 1810 for controlling wet conveyor 118, a module 1812 for controlling magazine 114, a module 1814 for controlling operator control panel 1708, and a module 1816 for controlling cassette/disk handling robot 104. Software program 1800 further comprises a set of global variables 1818 that are utilized and modified by the software modules in an event driven manner.

The machine AUTORUN mode represents a state wherein the substrate polishing apparatus is operating with all systems fully functioning and coordinated with one another via event driven handshake signals. Within a given module, the event driven handshake signals are achieved using the process of (a) recognizing that one or more relevant global variables has changed state, and (b) setting one or more global variables after performing the requisite action. In this manner, each mechanical subsystem operates separately yet interdependently with other mechanical subsystems. According to a preferred embodiment, coordination among the subsystems is not timing dependent according to an overall timing scheme, but rather is event driven with the separate software modules communicating via handshake signals. Each software module has its own separate schedule of events that are triggered by handshake signals received from other software modules. In this manner, the modular, event-oriented control strategy for substrate polishing apparatus 100 is achieved, with software modules controlling their associated mechanical subsystems and communicating with each other in a way that mirrors the mechanical interactions of the respective mechanical subsystems.

FIG. 19 shows a flow diagram of the event-driven software module 1816 that is exemplary of the modular, event-driven structure of the software modules used to control substrate polishing apparatus 100. As described previously, software module 1816 is designed to control the disk/cassette handling robot 104. Software module 1816 comprises instructions to implement the steps shown in FIG. 19, which shows a starting step 1902 followed by an event recognition step 1904. According to a preferred embodiment, starting step 1902 and event recognition step 1904 collectively achieve the functionality of keeping the disk/cassette handling robot 104 in its present mechanical state until the global variables 1818 match one of a plurality of conditions shown next to event recognition step 1904 in FIG. 19. Collectively, the steps 1902 and 1904 can be viewed as a scheduling step provided by a scheduler within the software module 1816.

By way of example and not by way of limitation, global variables 1818 comprise the following variables shown in the first two columns next to event recognition step 1904 in FIG. 19: CaddyOnDryShelf, CaddyReadyDCV, CarrierMoving, CaddyOnWetShelf, and DryShelfCaddyEmpty. The meaning and usage of the above global variables is generally consistent with their nomenclature, and thus the variable CarrierMoving is a boolean variable that is True ("T") when the carrier (i.e., the main gantry robot 108) is moving, and that is False ("F") when the carrier is not moving. At event recognition step 1904, the software module 1816 polls the global variables 1818 to recognize one of the plurality of conditions shown next to event recognition step 1904 in FIG. 19. If it happens that CaddyOnDryShelf is False (i.e., there are no cassettes on the dry shelf), CaddyReadyDCV is True (i.e., there is a cassette ready on the dry conveyor), and CarrierMoving is False (i.e., main gantry robot 108 is not currently moving) then a sequence of commands is executed at step 1906. In this example, based on the above global variable states, it is now time to move the caddies from the dry conveyor to the dry shelf, and therefore a functional routine CaddyDryConv-DryShelf is executed at step 1906. The running of the functional routine CaddyDryConv-DryShelf will, in turn, also change some global variables 1818 during its execution that will be recognized by other software modules, e.g. the module 1808 that controls the dry conveyor 102, that may trigger events in that other module. One such variable, for example, would be a variable RobotMoving, which would be set to True to communicate to all other modules that the cassette/disk handling robot 104 is in motion. After the functional routine CaddyDryConv-DryShelf is executed at step 1908, i.e. after the caddies have been moved from the dry conveyor to the dry shelf, the handshake step 1908 is executed, wherein certain global variables are reset in a handshake to other modules. In the above example where the functional routine

CaddyDryConv-DryShelf was run, the variable CaddyOnDryShelf is set to True (because the cassette is now on the dry shelf), CaddyReadyDCV is set to False (i.e., there is no cassette ready on the dry conveyor because they has just been moved), DryShelfCaddyEmpty is set to False (because there are substrates in the newly loaded cassette), DryDiskCount.T25 is set to True (initializing the number of unprocessed disks at the dry shelf to 25), and RobotMoving is set to False (because the cassette/disk handling robot 104 is no longer in motion).

If at event recognition step 1904 a different set of global variable states is found, such as the states shown at the second column to the right of event recognition step 1904 in FIG. 19, then the associated functional routines corresponding to that column are performed. Thus, if the variable states are CaddyOnDryShelf=T, Caddy On WetShelf=F, DryShelfCaddyEmpty^T, and CarrierMoving=F, then it is appropriate to move the caddies from the dry shelf to the wet shelf, and thus the functional subroutine CaddyDryShelf- WetShelf is executed at step 1906. As shown in FIG. 19 which corresponds to the software modules 1816 for controlling the cassette/disk handling robot 104, it is clear that many different global variable states can be recognized and a wide variety of functional subroutines can be called to instruct the cassette/disk handling robot 104 to perform various tasks. However, the disclosed modular, event-oriented control strategy, together with the subsequent process steps disclosed infra, should completely communicate to one skilled in the art the manner in which to construct and use the mechanical and software aspects of a substrate polishing apparatus in accordance with the preferred embodiments.

FIGS. 20-23 generally show a user interface associated with the substrate polishing apparatus 100 that also correspond to the modular programming structure used therein. In particular, the user selection of the options displayed invokes the execution of programmed software modules designed to achieve the corresponding functionality. As an example, FIG. 20 shows the main menu 2000 associated with the substrate polishing apparatus 100, comprising a CONFIGURATION buttons 2002 for instantiating a configuration menu/routine, a DIAGNOSTICS button 2004 for instantiating a diagnostics menu routine, and AUTORUN button 2006 for instantiating the modular, event-oriented AUTORUN mode described previously and at FIGS. 18-19, a HELP button 2008 for instantiating a help menu, and an EXIT button 2010.

FIG. 21 A shows a diagram of CONFIGURATION software 2100 containing modules that achieve the various configuration functionalities shown. While individual configuration functionalities of some entries are not described in detail, a person skilled in the art would readily be able to program and achieve such functionalities upon review of the present disclosure using the National Instruments BridgeView G-programming language or other similar programming tool. CONFIGURATION software 2100 comprises a

CALIBRATION module 2108 whose functionality is described further infra. FIG. 21B shows a user interface menu 2120 that corresponds to CONFIGURATION software 2100. FIG. 22A shows a diagram of the DIAGNOSTICS software 2200 containing modules that achieve the various diagnostics functionalities shown. FIGS. 22B and 22C show a user interface menu 2220 that corresponds to DIAGNOSTICS software 2200. As indicated at FIGS. 22B and 22C. the user interface menu 2220 presents the user several options according to the modules at FIG. 22A, depending on which first level submenu item (e.g., Dry Caddy, Wet Caddy, Dry Conveyor, etc.) is selected by the user. If an option is not relevant to the first level submenu item selected (e.g. Home Axes would not be relevant to the Operator Panel menu) then it is darkened to indicate lack of availability of that option. FIG. 23 A shows a diagram of the HELP software 2300 containing modules that achieve the various help functionalities shown. FIG. 23B shows a user interface menu 2320 that corresponds to HELP software 2300.

As shown in FIG. 2 IB. CONFIGURATION module 2100 comprises a PROCESS option 2102 that enables the user of the software, usually an operator or factory engineer, to modify various a parameters associated with the substrate polishing process. PROCESS option 2102 comprises a POLISH RECIPE module 2104 and a WEB RECIPE module 2106 that comprise recipe management software in accordance with the preferred embodiments. A recipe refers to a set of instructions and parameters that are used during the machine operating cycle.

FIG. 24 shows a block diagram of recipe management software 2400 in accordance with the preferred embodiments. Recipe management software 2400 comprises a user interface module 2402 that is designed and configured for intuitive, flexible configuration by the machine operator or factory engineer, such that various parameters and process steps can be modified with ease and flexibility. Recipe management software 2400 further comprises a loading module 2404 for loading the newly entered parameters into appropriate locations in the global variables 1818, which are denoted as process parameters 2406.

FIG. 25 shows a recipe editor parameter screen 2500 for entering parameters for use by the magazine system 1 14. Sequence editor parameter screen 2500 allows the user to enter desired parameters for magazine system parameters such as Web Distance, Web Speed, and Brush Speed for different steps of the process, each represented by a column of sequence editor parameter screen 2500 of FIG. 25. Each column represents a cluster of parameters, each cluster corresponding to one step of the sequence to be executed. If the user does not enter any values for a given parameter, the parameter remains unchanged. If the user enters a parameter that is clearly mistaken, i.e., outside an allowable upper or lower limit, the mistaken parameter value will be rejected and the previous value will remain unchanged to prevent possible harm to the system. PAGE UP and PAGE DOWN buttons are provided so that any number of sequence steps may be changed above the three steps that can be shown on an individual computer screen. Subsequent to the user^'s pressing of the OK button, the parameters are loaded by loading routines 2404 into the process parameters portion 2406 of global variables 1818.

FIG. 26 shows a recipe editor parameter screen 2600 for entering parameters for use by the orbiter 110 during the polishing process. Advantageously, the look and feel of the recipe editor parameter screen 2600 for the orbiter 110 is similar to the look and feel of the recipe editor parameter screen 2500 for the magazine 1 14. This provides a consistent and yet flexible user interface for changing process parameters which is also easier to program and debug.

FIG. 27 shows a recipe editor sequence screen 2700 for use by the orbiter 1 10 during the disk pickup sequence. This screen allows for further adjustment of environmental variables and instructions to be executed at each individual step of the disk pickup process.

Substrate Polishing Steps

FIG. 30-1, FIG. 30-2 and FIG. 30-3 show a flowchart showing the movement of an exemplary disk D from a time before the disk D is processed until a time after the disk D has been processed and removed from the substrate polishing apparatus 100. The disk D is contained among other disks in cassette 203 at a loading station (not shown). At step 3002, cassette 203 containing the disk D is transferred by the dry conveyor 102 from the loading station to a pickup station 205 located along the x axis of processing (position A in FIG. 1C). X axis of processing means a direction in which the disk D is translated from the pickup station to the disk rinse and flip station 106 and back and which is parallel to the horizontal movement of the cassette/disk handling robot 104 and the main gantry robot 108. It should be appreciated that each disk at the pickup station will have its own x axis of processing parallel to the other disks. For purposes of clarity the z axis is vertical, and the y axis is normal to the x axis and in the same plane as the x axis. In a preferred embodiment, the disk D is maintained in the plane defined by the x axis and the z axis which allows for design stability and efficiency resulting in a smaller apparatus and lower cost of construction. It should be appreciated that in a preferred embodiment, four disks are processed simultaneously; however, a substrate polishing apparatus can be designed to process more or less than four disks simultaneously. At step 3004, cassette 203 and other cassettes at the pickup station 205 are lifted by cassette/disk handling robot 104 and translated to a stationary shelf 220 and lowered thereon (position B in FIG. 1C). Advantageously, no gripping mechanism is required to couple the cassette 203 to the cassette/disk handling robot 104, as the cassette hooks 212 are adapted and configured to mate with recesses contained within the shape of cassette 203. The lifting of the cassette 203 in the z direction is achieved by a vertical movement of end effector shaft 210 whereas the translation is achieved by the horizontal movement of the cassette/disk handling robot 104. It should be appreciated that the cassettes are oriented such that the disk D is in the y-z plane. At step 3006, disk D is lifted out of cassette 203 by cassette/disk handling robot 104 and translated to the disk flip and rinse station 106. Advantageously, the disk D is lifted by the same end effector 206 which lifted the cassette 203 from the dry conveyor 102 to the stationary shelf 220 but using the passive fingers 222. Advantageously, the cassette/disk handling robot 104 is only required to maintain the disk in a vertical, upright position providing simplicity of design. Also, the passive fingers 222 used to lift the disk D do not grip the surface of the disk D. Specifically, the cassette/disk handling robot 104 moves horizontally along the x axis to a position on the closest side of the cassette 203 (i.e., the side closest to the center of the substrate polishing apparatus 100). The cassette/disk handling robot 104 then moves vertically until the passive fingers 222 are aligned with the center of the disk D, at which point, the cassette/disk handling robot 104 moves horizontally until the passive fingers 222 are inside the disk D and three other disks. The cassette/disk handling robot 104 then moves vertically upward to lift the disk D from the cassette 203. The cassette/disk handling robot 104 then moves horizontally and then vertically downward until horizontally aligned with the disk holder fingers 314, at which point, the cassette/disk handling robot 104 moves horizontally toward the disk flipper 308, as described previously. When deposited at the disk flip and rinse station 106 the disk D is received by the disk holders 312 that have been positioned in an upright position in the y-z plane. During this step the disk 201 is affirmatively seized, as described previously, by the disk holding fingers 314 actuated by a vacuum actuation mechanism which is controlled by disk flip and rinse software module 1606.

At step 3008 the disk D is rotated about the y axis in the x-z plane by disk flipper 308 to a horizontal position in the x-y plane onto its respective submerged hydrodynamic substrate presenter mechanism 316. After this step the disk in now submerged in water, preferably deionized water. At step 3010, the disk polish heads 1 12 are positioned directly over the horizontally positioned disk D on mechanism 316 by means of the main gantry robot 108, with the orbiter 1 10 in the appropriate orbiter position.

At step 3012, the disk polish heads 1 12 are lowered and then seize and raise the disk D for subsequent translation to the magazine 1 14. Importantly, in accordance with a preferred embodiment, the disk polish heads 1 12 are not required to be submersed in the water during the step 3012. Rather, the submerged hydrodynamic substrate presenter mechanism 316 is actuated by the disk flip and rinse module 1606 using controlled water pressure to raise the disk D above the water level. Disk D is seized preferably at a point just above the surface of the water by means of negative fluid pressure generated by a peristaltic pump connected to the disk polish head 1 12. According to a preferred embodiment, the fluid is a water, but air can also be used. By way of example, this process step is described in more detail below in connection with FIG. 32.

At step 3014, the disk D is translated along the x axis to a position over the magazine 1 14 (position P in FIG. 1C) and lowered onto the web tape 1 15 of the magazine 1 14. The translation from the disk flip and rinse station 106 to the magazine 1 14 is achieved by means of the gantry robot 108. Upon arriving at the polish position P, the motion restraint system secures the gantry robot as explained below in connection with FIG. 34. The lowering of the disk D onto the web tape 1 15 is achieved using the orbiter vertical motion robot 113. Once the disk D has been lowered onto the web tape 115, the disk D is released from the disk polish head 112 by means of positive pressure generated in the disk pickup manifold system as described below in connection with FIG. 33.

At step 3016, a first side (i.e., lower) of the disk D is polished by means of orbital motion imparted by the orbiter 1 10. The motion of the disk polish head 112 is circular above the web tape 1 15, maintaining a constant orientation in the y direction. Generally, although the process may be configured for a variety of orbit sizes, the orbit radius is typically a predetermined fraction of the disk, for example, one fifth.

Importantly, the pressure exerted on the disk D during polishing is closely modulated by the disk polish head 112, which is adapted and configured to achieve precise, yet adjustable, pressure on the disk as shown in FIG. 7A. Software module 1604 is programmed to modulate air pressure used by the disk polish heads 1 12 to achieve a desired, predetermined pressure on the disk D. The predetermined pressure may be adjusted by the operator or factory engineer as necessary using the recipe editor features in accordance with a preferred embodiment. At step 3018 the disk D is translated from the magazine 1 14 back to the disk flip and rinse station 106, specifically, the disk rinse compartment 306 of the disk flip and rinse station 106 (see, e.g., FIG. 1C). The translation from the magazine 1 14 to the disk flip and rinse station 106 is achieved by the disk polish head seizing the disk D by means of negative fluid pressure generated by a peristaltic pump connected to the disk polish head 1 12, raising the disk polish head 201 using the orbiter vertical motion robot 1 13 and moving the main gantry robot 108 horizontally along the x axis until the disk D is positioned above the disk rinse compartment 306.

At step 3020, the disk D is lowered into the disk rinse compartment 306

10 where any remaining polishing slurry on the disk D is rinsed by the spray nozzles 354. The disk D is lowered using the orbiter vertical motion robot 113. As the disk D is lowered into the disk rinse compartment 306. disk flip and rinse module 1606 actuates the spray nozzles 354 using controlled water pressure thereby causing them to spray the lower side of the disk D and to rotate in a circular pattern about the vertical- axis to which they are attached.

1 At step 3022, the disk D is translated from the disk rinse compartment 306 onto the hydrodynamic substrate holder mechanism 336. The disk D is raised from the disk rinse compartment 306 using the orbiter vertical motion robot 1 13, moved horizontally along the x axis to a position above the submerged hydrodynamic substrate holder mechanism 336 and lowered onto the submerged hydrodynamic substrate holder mechanism

20 336 by the orbiter vertical motion robot 113. As the disk D is lowered onto the submerged hydrodynamic substrate holder mechanism 336, disk flip and rinse module 1606 actuates the submerged hydrodynamic substrate holder mechanism 336 using controlled water pressure to spray the lower side of the disk D. Once the disk D is positioned on the submerged hydrodynamic substrate holder mechanism 336, the disk polish head 112 releases the disk

2 using positive fluid pressure generated by reversing a peristaltic pump connected to the disk polish head 112.

At step 3024, the disk D is rotated 180 degrees about the y axis from its horizontal position (i.e., inverted) on the submerged hydrodynamic substrate holder mechanism 336 to a horizontal position on the submerged hydrodynamic substrate presenter

30 mechanism 316 by the disk flipper 308. It should be appreciated that this step 3024 effectively turns the disk D over such that the polished side of the disk D is now facing upward. Further, it should be appreciated that during this step neither the submerged hydrodynamic substrate holder mechanism 336 nor the submerged hydrodynamic substrate presenter mechanism 316 are actuated using controlled water pressure. Still further, it 35 should be appreciated that the disk D before and after this step 3024 is submerged under water as the water level is maintained by the weir 360.

At step 3026, the other side of the disk D is processed by repeating steps

3010 through 3022. At step 3028, the now completely polished disk D is rotated about the y axis to a vertical position in the y-z plane by the disk flipper 308.

At step 3030, the disk D is translated from the disk flip and rinse station 106 to a cassette (not shown) located on the submerged stationary shelf 221 (position W in FIG.

1 C). This translation is achieved by the cassette/disk handling robot 104 which receives the disk D from the disk flipper 308 by moving to a position horizontally aligned along the x axis with the center of the disk D. The cassette/disk handling robot 104 then moves horizontally to position the passive fingers 222 within the center of the disk D and three other disks, at which point the disk holders 312 release the disk D. The cassette/disk handling robot 104 then moves horizontally along the x axis to a position above a submerged cassette located on the submerged stationary shelf 221. The cassette/disk handling robot 104 moves vertically downward and releases the disk D into the submerged cassette.

At step 3032, once the submerged cassette has received all of the disks to be processed, it is lifted from the submerged stationary shelf 221 to the wet conveyor 1 18 by the cassette/disk handling robot 104. This translation is achieved using the cassette hooks

212 as previously described for translation of the cassette 203 from the dry conveyor 102 to the stationary shelf 220.

At step 3034. the submerged cassette is moved from its initial position on the wet conveyor 1 18 to a off-loading station (not shown) using the wet conveyor 1 18. The cassette may be retrieved at the off-loading station manually or by another machine for further processing.

At step 3036, after all of the disk in the cassette 203 have been processed, cassette 203 is moved from the stationary shelf 220 to the submerged stationary shelf 221 using the cassette/disk handling robot 104. It should be appreciated that in a preferred embodiment, the substrate polishing apparatus 100 is operated in a continuous fashion such that two sets of four disk each are being processed concurrently. Therefore, certain steps in FIG. 30 are actually performed concurrently but for a second set of disks.

FIG. 31 -1 and FIG. 31-2 show the sequence of steps shown in FIG. 30 for three sets of disks wherein each set of disks is a group of four disks each retrieved from separate cassettes and which are processed simultaneously. FIG. 31-1 and FIG. 31-2 are intended to show which steps for one set of disks are occurring at the same time as another set of disks to show how the present invention operates in a continuous processing mode. After step 3006 for the first set of disks, the cassette/disk handling robot 104 is free to perform the steps 3006 through 3008 for the second set of disks. Therefore, the steps 3006 through 3008 for the second set of disks may occur while the steps 3008 through 3016 are being performed for the first set of disks. After the step 3022 is performed for the first set of disks, the main gantry robot 108 is free to perform the steps 3010 through 3014 for the second set of disks. Once the main gantry robot 108 moves away from the disk flip and rinse station 106 to perform the steps 3016 through 3022 for the second set of disks, the step 3024 is performed for the first set of disks and the step 3026 which involves repeating the steps 3010 through 3022 for the second side of the first set of disks.

After the step 3014 is performed for the second side of the first set of disks, the main gantry robot 108 moves away from the disk flip and rinse station 106 which allows the step 3024 to be performed for the second set of disks. After the step 3022 is performed for the second side of the first set of disks, the main gantry robot 108 is free to perform the step 3026, specifically the steps 3010 through 3014 for the second side of the second set of disks. While the step 3028 is being performed for the first set of disks, the step 3016 can be performed for the second side of the second set of disks. Also, during this time, the cassette/disk handling robot 104 if free to perform the step 3006 for a third set of disks. It should be appreciated at this point that as the cassette/disk handling robot 104 performs the step 3030 for the first set of disks it sequentially performs the step 3008 for the third set of disks. Specifically, once the cassette/disk handling robot 106 moves the third set of disks from the cassettes to the disk flip and rinse station 106, the cassette/disk handling robot 104 first retrieves the first set of disks from the disk flipper 308 and then releases the third set of disks to the disk flipper 308 before completing the step 3030 by taking the first set of disks to the submerged cassettes. Once the cassette/disk handling robot 104 moves away from the disk flip and rinse station to the submerged cassettes with the first set of disks, the steps 3018 through 3022 can be performed for the second side of the second set of disks. After the step 3022 is performed for the second side of the second set of disks by the main gantry robot 108, the steps 3010 through 3014 can be performed by the main gantry robot 108 for the third set of disks. Once the main gantry robot 108 moves away from the disk flip and rinse station (the step 3014), the step 3028 is performed for the second set of disks during which time the step 3016 is performed for the first side of the third set of disks. At this point, the cassette/disk handling robot 106 is free to perform the step 3006 and the step 3008 for a forth set of disks (not shown) and to then sequentially perform the step 3030 for the second set of disks.

One of skill in the art can appreciate how a disk D, wherein i is an integer from 1 to n where n is the number of disks to be polished, is processed. Furthermore, one of skill in the art can appreciate that D may represent a set of disks that are processed simultaneously and n is the number of disk sets to be processed. It should be appreciated that the process will continue until the last set of disks in a given set of cassettes is processed, at which point, the steps 3032 through 3036 are performed. One of skill in the art can easily envision from this description how the process continues with another set of cassettes.

It should be appreciated that as the last set of disks in a given cassette, or set of four cassettes, is polished, some steps will not need to be performed. For example, if an even number of disks were to be polished, while the second side of last set of disks is being polished, the cassette/disk handling robot 104 will not retrieve another set of disks from the cassettes, i.e., step 3006-3008 will not be performed. Instead, the step 3028 for the second to last set of disks will be performed and the cassette/disk handling robot 104 will only execute the step 3030. Similarly, after polishing the second side of the last set of disks and executing the step 3022, the main gantry robot 108 moves back towards the polishing station. Then the step 3028 is executed for the last set of disks, and the cassette/disk handling robot 104 will only execute the step 3030.

If the number of disks to be polished is odd, then while the first side of the last set of disks is being polished, the cassette/disk handling robot 104 will not retrieve another set of disks from the cassettes, i.e., step 3006-3008 will not be performed. Instead, the step 3028 for the second to last set of disks will be performed and the cassette/disk handling robot 104 will only execute the step 3030. At this point, only the first side of the last set of disks will have been polished. Therefore, after the step 3022, the main gantry robot 108 moves back towards the polishing station and the step 3024 and those following are executed thereby polishing the second side of the last set of disks. Furthermore, after polishing the second side of the last set of disks and executing the step 3022, the main gantry robot 108 moves back towards the polishing station. Then the step 3028 is executed for the last set of disks, and the cassette/disk handling robot 104 will only execute the step 3030.

It should be appreciated that the operation of the magazine 1 14 described above also occurs during some of the above steps. Specifically, the operation of the magazine occurs in between the performance of the polishing step 3016. It will also be appreciated by persons skilled in the art that the above described multi-disk set processing sequence is merely illustrative of many possible sequences which may be advantageously employed by the present invention, with the basic constraint that various disk handling approaches cannot occupy the same space at the same time. FIG. 32 shows the process algorithm for lifting a disk using the system described in connection with FIG. 13. It should be appreciated that the disk polish heads 112 are positioned over the disks to be lifted before beginning the steps shown in FIG. 32. At the step 3202 the mixing manifold 1308 is set to allow water to pass from the inlet water line 1305 to the water lines 1302, and the outlet valve 1320 is opened. In addition, at the step 3202. the negative pressure peristaltic pump 1304 is operated but at a slow speed. At the step 3204 and 3206, the inlet water valve 1306 is then opened for a predetermined time to allow water to pass through both the water lines 1302 and the waste line 1318, including the pump 1304. Passing water through the water lines 1302 provides a film of water between the bottom of the disk polish head 112, specifically the disk plate 704. and the disk. In addition, it should be appreciated that all of the water lines 1302 will be filled with air as a result of previously having released a disk as will be described below in connection with FIG. 33. At the step 3210, the speed of the pump 1304 is increased to pull water back through the water lines 1302 and to discharge the water through the waste line 1318. This creates a suction effect such that the water film between the bottom of the disk plate 704 and the disk effectively pulls the disk to the bottom of the disk plate 704. At the step 3212 a pressure reading taken by the computer system 120 using the pressure sensor 1322 is compared to a setpoint. Typically, the measured pressure should be approximately -11 psi to effectively secure the disk to the bottom of the disk plate 704. The step 3212 is repeated until the setpoint pressure is achieved using the pump 1304. It should be appreciated that the pressure necessary to secure the disk to the disk plate will vary depending upon the exact design of the disk plate and the design of the system used to lift and release the disk.

Once the setpoint pressure is achieved, the step 3214 is performed whereby the disk polish heads 112 are raised a small amount. In the step 3216, the computer system 120 then compares another pressure reading from the pressure sensors 1322 to the setpoint. If the measure pressure is not maintained at the setpoint, the step 3216 is performed in which the disk polish heads are lowered back to their starting position and the process starts over at the step 3204. If the setpoint pressure is still maintained the disk polish heads 1 12 can be moved holding the disk. It would be clear to one of skill in the art, that a counter can be programmed to count the number of failed attempts to lift the disk polish heads such that after a certain number of attempts, a failure would be indicated to the user. FIG. 33 shows the process algorithm for releasing a disk using the system described in connection with FIG. 13. It should be appreciated that the disk polish heads 1 12 are positioned over the disk flip and rinse station 106 or the magazine 114 before releasing the disks held by the disk polish heads 112. Once the disk polish heads are in position, the process steps shown in FIG 33 may be performed. Generally, the air inlet valve 1312 is opened to opened thereby allowing pressured system air to pass through the mixing manifold 1308 and into the water lines 1302. Since air also will flow through the negative peristaltic pump 1304 and the waste valve 1320, the pump 1304 is turned off and the waste valve 1320 is closed. The process algorithm of FIG. 33 includes a feedback loop which iterates on the pressure measured in the water lines 1302 to insure sufficient air pressure is available to push the disk off of the disk plate 704.

In an alternative embodiment, it may not be necessary to monitor the air pressure to insure release of the disk. In this case, the pump 1304 is turned off and the waste valve 1320 is closed. The air inlet valve 1312 is opened and pressurized air flows through the mixing manifold 1308 and fills the water lines 1302 thereby using positive pressure to force the disk off of the disk plate 704.

It should be appreciated that when the disk is released to the submerged hydrodynamic disk holder mechanism 336 in the disk flip and rinse station 106 that the disk polish heads 112 are lowered below the surface of the water and then the air inlet valve 1312 is opened. In addition, after the disk is forced off of the disk plate 704, the air inlet valve 1312 is allowed to remain open as the disk polish heads 112 are moved vertically upward and away from the submerged hydrodynamic disk holder mechanism 336. This insures that the disk remains on the holder mechanism 336 and does not adhere to the disk plate 704 by virtue of the water in the disk flip and rinse station 106. This is as opposed to release of a disk onto the magazine 1 14 in which the air inlet valve is closed before moving the disk polish heads 112.

FIG. 34 shows one embodiment of an algorithm for controlling an air actuated brake assembly such as those previously described in reference to FIG. 4B and FIG. 4C. Specifically, this algorithm shows the steps for actuating such a brake assembly by using an air valve such as the air valve 440 once the main gantry robot 108 is in a position for polishing. A feedback loop is included which continues actuation of the brake assembly until polishing is completed. Another feedback loop is then used to insure that the air pressure within the brake assembly has been reduced such that the main gantry robot may be moved. Other embodiments for controlling an air valve and an air actuated brake assembly would be clear to one of skill in the art. Calibration of Polishing Heads

FIG. 35 shows steps used to control vertical forces exerted by disk polish heads 1 12 on the disk 201 and the web tape 1 15 during polishing. For clarity of disclosure, the control of a single polishing head is described, it being understood that separate but similar steps and parameters are used to control all four polishing heads 112. For each polishing head such as that shown in FIG. 7, the disk plate 704 is driven by a disk command pressure Phg, while the plastic ring carrier 706 and metal ring carrier 708 are driven by a ring command pressure Prg. Because of the structure of the polishing head as shown in FIG. 7, computation and application of the disk command pressure Phg and the ring command pressure Prg present a control problem in that there is cross-coupling between the effects of the ring command pressure Prg and disk command pressure Phg, and therefore an optimal solution for the control pressures Prg and Phg must be computed.

At step 3502, in a calibration process prior to disk polishing that is usually performed at very long intervals as compared to the cycle time for a single disk substrate, e.g. once per week, the calibration fixture 900 is coupled to the disk polish heads 112. The calibration fixture 900 is coupled to the corporate network over a TCP/IP link or other communication protocol to communicate measurements to the control system 120 via the corporate network 1714. According to a preferred embodiment, calibration fixture 900 measures forces exerted on the disk plate 704 and ring carrier 706 that correspond to a plurality of different combinations of test values for disk command pressure Phg and ring command pressure Prg, and these forces are then used to determine an open-loop control law using steps described herein for 'use by the control system 120 during normal operation. At step 3504, a test pressure counter variable k is initialized to 1. At step 3506, test pressures Phg(k) and Prg(k) correspond to the pressure counter variable k are applied by the control system 120. The actual values for test pressures Phg(k) and Prg(k), which will be described infra, are generally chosen to fill the range of possible control pairs (Prg, Phg) that may be used during normal operation.

At step 3508, resultant forces on the three ring loadcell sensors 910 and the three disk loadcell sensors 911 are measured and communicated to the control system 120 via the TCP/IP link connecting substrate polishing apparatus 100 to the corporate network

1714. At step 3510, resultant load forces FDISK(k) and FRING(k) are computed from the three ring loadcell measurements and the three disk loadcell measurements using. Although the scope of the preferred embodiments is not so limited, one manner in which to compute

FDISK(k) from the three disk loadcell measurements is to compute their sum, and one manner in which to compute FRING(k) from the three ring disk loadcell measurements is to compute their sum as well.

At step 3512, it is determined whether an adequate number of samples has been taken by comparing the counter variable k to a predetermined variable NUMSAMP. While the predetermined variable NUMSAMP can be empirically adjusted to a wide variety of values by factory engineers or other personnel, one typical calibration process may take 10 samples. If k is not greater than or equal to NUMSAMP, it is incremented at step 3513 and the steps 3506-3510 are repeated.

At step 3514, which is executed when the predetermined number of samples has been taken, the calibration fixture 900 is removed and a plurality calibration constants A, B, C, and D are computed, using steps described infra. Upon the completion of step 3514, the calibration process is complete.

At step 3516, which is carried out by the system operator or factory engineers prior to actual production run of the substrate polishing apparatus 100, the desired disk pressure PDISK and the desired ring pressure PRING are entered using the user interface described with respect to the CONFIGURATION previously. Finally, at step 3518, the actual ring command pressure Prg and disk command pressure Phg are computed based on the values of PRING, PDISK, the , calibration constants A, B, C, and D, and the variable ADISK which represents the area of the disk substrate 201 that is to be polished. The formula used to compute Prg and Phg is shown at step 3518 of FIG. 35. The values Prg and Phg are used as open-loop control pressures, which remain in effect until re-calibration of the disk polish heads, the changing of the desired ring pressure PRING, or the changing of the desired disk pressure PDISK.

FIG. 36 shows a table 3602 that may be stored in computer memory for use by control system 120 during the calibration process. In the example shown at FIG. 36, which is presented by way of explanation only and not by way of limitation, it being understood that a variety of different sample numbers and applied sample pressures can be used, the number of pressure samples NUMSAMP is set to 9. For the first sample calibration measurement, a test disk pressure Phg(l) of 4 PSI is applied at the same time as a test ring pressure Prg(l) of 2 PSI.. For the sixth sample calibration measurement, a test disk pressure Phg(6) of 7 PSI is applied at the same time as a test ring pressure Prg(6) of 8 PSI, and so on. As discussed with respect to steps 3508 and 3510 of FIG. 35, the load forces FDISK(k) and FRING(k) are determined and stored in computer memory for use at step

3514 to determine the calibration constants A, B, C, and D. FIG. 37 shows steps corresponding to step 3514 of FIG. 35 to determine the calibration constants A, B, C, and D based on measurements taken by the calibration fixture 900. Generally speaking, the calibration constants A, B, C, and D can be solved for using measurement values corresponding to only two test sample pairs Phg and Prg. However, in accordance with a preferred embodiment, measurements corresponding to several test sample pairs Phg and Prg are used to derived several different estimates A(n), B(n), C(n), and D(n), and then optimal values for the calibration constants A, B, C, and D are derived from the statistics A(n), B(n), C(n), and D(n) after singularities such as negative numbers or clear data spikes are removed. While in a preferred embodiment an averaging technique is used, many possible statistical metrics from the sample populations A(n), B(n), C(n), and D(n) may be used, such as root mean square metrics, without departing from the scope of the preferred embodiments. In this manner, reliable and practical values for the calibration constants A, B, C, and D are derived.

At step 3702, the one-dimensional matrices Phg(k), Prg(k), FDISK(k), and FRING(k), which are each NUMSAMP elements long, are retrieved from computer memory. At step 3704, a combination counter variable n is initialized to 1. At step 3708, values for Prgl, Phgl, FDISK1, and FRING1 are selected corresponding to a first calibration sample taken at steps 3506 and 3510 for a first value of sample counter k in FIG. 35. Also at step 3708, values for Prg2, Phg2, FDISK2, and FRING2 are selected corresponding to a second calibration sample taken at steps 3506 and 3510 for a second value of sample counter k in FIG. 35.

At step 3710, for' the above values corresponding to the n^th combination of calibration samples, the estimated A(n), B(n), C(n), and D(n) are computed using the formulae shown at step 3710 of FIG. 37. At step 3714, the combination counter variable n is compared to a predetermined number of possible combinations NUMCOMB to determine whether further combinations are required. If the combination counter variable n is less than NUMCOMB, it is incremented at step 3712 and steps 3708 and 3710 are repeated. Otherwise, step 3716 is performed.

At step 3716, the singularities of the estimates A(n), B(n), C(n), and D(n) are removed. A singularity is a value that is clearly incorrect (such as a negative number for a quantity that is expected to be positive) or far outside the range of expected values. Finally, at step 3718, the values A, B, C, and D are computed from the matrices using a simple arithmetic average.

FIG. 38 shows a table 3802 that may be stored in computer memory for dictating the possible combinations of calibration samples used to form the one-dimensional matrices A(n), B(n), C(n), and D(n). Table 3802 corresponds to the table 3602 of FIG. 36 in that it represents a case where NUMSAMP = 9 sample pressure pairs Phg, Prg were used, although it is to be appreciated that the table 3802 can grow much larger if a larger number of samples is taken. In use, the table 3802 would be referenced by the computer program executing the step 3708 of FIG. 37. For example, for n = 5 in FIG. 37, the table 3802 of FIG. 38 would return a value of REF2(5) = 6, and REF1(5) = 1. Therefore, the measurement values from the 6^th sample pressure pair and 1 ^st sample pressure pair in generating the values of A(5), B(5), C(5), and D(5) at step 3710.

In the preferred embodiment o FIG. 38, there are NUMCOMB = 36 different combinations of the 9 sample pressure pair measurements, which represents the maximum number of unique pairs that can be taken from a population of 9. However, table 3802 is only one representation of a combination table that may be formed in accordance with the preferred embodiment, and tables having fewer combinations having fewer than the maximum number are also within the scope of the preferred embodiments. It is also within the scope of the preferred embodiments to consider some combinations as being more important than other combinations and afford them a relative weighting in the computation of the calibration constants A, B, C, and D.

FIG. 39 shows a user interface screen 3900 for viewing parameters associated with the forces exerted by disk polishing heads 1 12. User interface screen 3900 may be used to view parameters during the calibration process as well as during normal operation of the substrate polishing apparatus 100.

Various embodiments of the invention have been described. The descriptions are intended to be illustrative of the present invention. It will be apparent to one of skill in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below. For example, it is to be understood that although the invention has been described using as an example the polishing of a magnetic disk, any substrate may be polished by the present invention. Furthermore, it is to be understood that although the invention has been described for polishing magnetic disks, any method or apparatus for automatically polishing both sides of a substrate is contemplated to fall within the scope of the invention.

Claims

CLAIMSWhat is claimed is:

1. A method for polishing planar members having first and second opposed sides, comprising: presenting the member at a polish location with the first side oriented toward a polish media; polishing said first side against said polish media; removing the member from the polish location; inverting said first substrate to orient the second side toward the polish media: presenting said member at the polish location with the second side oriented toward the polish media; and polishing said second side against the polish media.

2. The method according to claim 1, wherein said planar member is a magnetic disk substrate.

3. The method according to claim 1 , wherein said removing step comprises translating the member to a position remote from said polish position and depositing the member at said remote location.

4. The method according to claim 3, wherein said inverting step comprises inverting the member at the remote location.

5. The method according to claim 4, further comprising placing said member at said remote location prior to initially presenting the member at the polish location and wherein said presenting steps each comprise retrieving said member from said remote location and translating the member to the polish location.

6. The method according to claim 5, wherein a series of said members D, _{(l =} , ,_{0 n)} are sequentially polished with each subsequent member in said sequence (D,_{+ 1}) being delivered to the remote location during at least one of the presenting and polishing of the preceding member (D,).

7. The method according to claim 5, wherein: said remote location comprises a deposit position and a retrieval position; said inverting step comprises transferring the member from the deposit position to the retrieval position; said depositing step comprises depositing the member at the deposit position; and said retrieving step comprises retrieving the member from the retrieval position.

8. The method according to claim 7, wherein said placing step comprises translating the member from an initial position and placing the member at a pre-retrieval position, said remote location additionally including said pre-retrieval position.

9. The method according to claim 8, wherein a series of said members

Di ₍ i ₌ i _{to n)} ^are sequentially polished, with each subsequent member in said sequence (D,₊₁) being delivered to the remote location during at least one of the presenting and polishing of the preceding member (D,), said method further comprising:

(a) placing a subsequent member (D,N);

(b) removing a preceding member (D,);

(c) transferring the subsequent member (D_{1+ 1}) from the pre-retrieval position to the retrieval position; (d) retrieving said subsequent member (D,₊,) after steps (a)-(c);

(e) translating the subsequent member (D,N) to the polish position;

(f) inverting the preceding member (D,) after step (d); and

(g) polishing the first side of the subsequent member (D,₊₁).

10. The method according to claim 9, further comprising:

(h) removing the subsequent member (D,₊,);

(i) presenting the preceding member (D,) with the second side oriented toward the polish media;

(j) polishing the second side of the preceding member (D,); (k) inverting the subsequent member (D,_{+ |}); (1) removing the preceding member (D,);

(m) presenting the subsequent member (D₁₊₁) with the second side oriented toward the polish media; and

(n) polishing the second side of the subsequent member (D,₊₁).

11. The method according to claim 10, further comprising:

(o) moving the preceding member (D,) to the pre-retrieval position; (p) transferring the preceding member (D,) from the pre-retrieval position to an exit position; (q) placing a further member (D,₊₂);

(r) repeating steps (b) - (q) with respect to members D,₊₂ through D_n.

12. The method according to claim 9, wherein D, represents a set of plurality of members processed in parallel with each other.

13. The method according to claim 8, wherein said planar members are held in a vertical orientation during said placing steps and held in a horizontal orientation during said presenting and removing steps.

14. The method according to claim 8, wherein: said initial position comprises a shelf; said remote location comprises station said polish location comprises a polish surface: said presenting comprises picking up and translating a member from said flip station to the polish surface via a first robot; said placing comprises picking up and translating a member from said shelf to said station via a first robot; and said removing comprises picking up and translating a member from the polish surface to said station via said first robot.

15. The method according to claim 14, wherein said planar member is a magnetic disk substrate and said method further comprises holding the member against the polish media on the polish surface with the first robot.

16. The method of claim 15 further comprising the steps of: loading a cassette for holding said substrate from a dry conveyor onto a shelf using a second robot; moving said cassette from said shelf to a submerged shelf using said first robot; and unloading said cassette from said submerged shelf to a submerged conveyor.

17. The method of claim 16 further comprising: conveying a second substrate from the shelf to said station by contacting only the edges of said second substrate using a first robot; translating said second substrate from said station to said polish surface using said first robot; transferring said second substrate having two polished sides from said polish surface to said station using said first robot; and carrying said second substrate having two polished sides from said station to a submerged shelf by contacting only the edges of said second substrate having two polished sides using said second robot.

18. The method of claim 17 wherein said second robot performs said conveying and said carrying by inserting a passive finger into an opening defined by said second substrate.

19. The method of claim 17 wherein said transferring and said translating are performed by securing said second substrate to a disk polish head attached to said first robot before said transferring and said translating and releasing said substrate after said transferring and said translating.

20. The method of claim 19 wherein said securing is accomplished by applying negative pressure to a fluid which is in fluid contact with a bottom surface of said disk polish head, and said releasing is accomplished by applying positive pressure to said fluid.

21. The method of claim 20 wherein said fluid is water.

22. The method of claim 17 further comprising carrying a first substrate from said station to said submerged shelf after said conveying wherein said second robot releases said second substrate to said station and then retrieves said first substrate from said station.

23. The method of claim 21 wherein said carrying of said first substrate step is performed by said second robot by a passive finger capable of holding said second substrate on one side and said first substrate on the opposite side.

24. The method of claim 17 wherein said conveying further comprises conveying said second substrate from said shelf to said flip station by contacting only the edges of said second substrate using said second robot while said second side and said first side are both maintained in approximately vertical planes, and further comprising: releasing said second substrate to a rotatable substrate holder which closes a pair of substrate holding fingers such that said rotatable substrate holder grips said second substrate by the edges of said second side and said first side; rotating said second substrate such that said second side and said first side are both in horizontal planes using said rotatable substrate holder; placing said second substrate on a presenter mechanism having a slidable upper presenter body member by opening said pair of substrate holding fingers; and extending said slidable upper presenter body member and thereby said second substrate towards said bottom surface of said disk polish head before each of said translating steps.

25. The method of claim 16 wherein each of said polishing steps is accomplished by using an orbiter to move a disk polish head, which retains said second substrate, in a circular orbit and which is restricted from rotating about its own axis.

26. The method of claim 24 wherein each of said polishing steps further comprise polishing by moving said second substrate in a circular orbit and allowing said second substrate to move freely about its own axis.

27. The method of claim 24 further comprising: applying pressure to a seal plate of said disk polish head; and separately applying pressure to a plastic retainer ring of said disk polish head.

28. The method of claim 13 further comprising simultaneously polishing a plurality of substrates using a disk polish head for each said substrate wherein each of said disk polish heads is connected to said orbiter which moves each of said disk polish heads in a circular orbit.

29. The method of claim 24 further comprising simultaneously polishing a plurality of substrates using a disk polish head for each said substrate wherein each of said disk polish heads is separately connected to a separate orbiter which separately moves each of said disk polish heads in a circular orbit.

30. The method of claim 16 wherein said transferring step further comprises: releasing said second substrate having a second polished side from a disk polish head to a holder mechanism having a slidable upper holder body member with a holder spray nozzle and injecting water through said slidable upper holder body member and said holder spray nozzle toward said second polished side and placing said second substrate on said holder mechanism underwater such that said second polished side and said first side are both in approximately horizontal planes and said second polished side is positioned below said first side; gripping said second substrate using a rotatable substrate holder which closes a pair of substrate holding fingers such that said rotatable substrate holder grips said second substrate by the edges of said second polished side and said first side; and wherein said inverting step is accomplished by rotating said rotatable substrate holder such that said second polished side is positioned above said first side.

31. The method of claim 16 further comprising the step of rinsing said second side of said second substrate after said polishing a second side step and rinsing said first side of said second substrate after said polishing said first side step.

32. The method of claim 30 wherein said rinsing steps include positioning said second substrate above a rinse spray nozzle using said second robot and spraying water toward said second substrate.

33. An apparatus for polishing planar members having first and second opposed sides, comprising: means for polishing a side of the member at a polish location including a polish media; means for presenting the member at the polish location with one side oriented towards the polish media; and means for inverting the member to present the opposite side to the polish media.

34. The apparatus according to claim 33, further comprising means for placing the member on said inverting means.

35. The apparatus according to claim 34, wherein said members are magnetic disk substrates.

36. The apparatus according to claim 35, wherein: said polishing means comprises a polish surface on which the polish media is held; said presenting means comprises a first robot including an orbiter for holding the substrate by one sided and presenting the opposite side to the polish media; said inverting means comprises a station which receives the substrate from said first robot after polishing said first side and which inverts said first substrate; and wherein said first robot transfers said substrate having a first polished side from said polish station to said flip station and translates said first substrate from said station to said polish surface after said first substrate is inverted.

37. The apparatus according to claim 36, wherein said placing means comprises a second robot for loading a cassette, said cassette holding said first substrate, from a dry conveyor onto a shelf, moving said cassette from said shelf to a submerged shelf and unloading said cassette from said submerged shelf to a submerged conveyor.

38. The apparatus according to claim 36, wherein said placing means comprises a second robot for conveying said first substrate from a shelf to said flip station, translating said first substrate from said flip station to said polish surface, transferring said first substrate having two polished sides from said polish station to said flip station and carrying said first substrate have two polished sides from said flip station to a submerged shelf.

39. The apparatus according to claim 38 wherein said second robot further comprises: a robot body attached to a horizontal drive screw assembly; a vertical drive screw assembly attached to said robot body; and an end effector attached to said vertical drive screw assembly and having a first passive finger for conveying, translating, transferring and carrying said first substrate which can be inserted into an opening defined by said first substrate thereby only contacting an edge of said first substrate and a cassette hook for lifting a cassette for holding said substrate.

40. The apparatus according to claim 39 further comprising a second passive finger opposing said first passive finger whereby said cassette/disk handling robot can move ^" said first substrate to said flip station using said first passive finger, retrieve a polished substrate from said flip station using said second passive finger as the next sequential step performed by said cassette/disk handling robot.

41. The apparatus according to claim 36, wherein said presenting means further comprising a disk polish head attached to said orbiter for securing said first substrate when said first robot transfers said first substrate having a first polished side from said polish station to said flip station and when said first robot translates said first substrate from said flip station to said polish surface after said first substrate is inverted and for retaining said first substrate during polishing.

42. The apparatus of claim 36 wherein station further comprises: a disk flip compartment;- a disk rinse compartment attached to said disk flip compartment and having a plurality of spray nozzles; a plurality of presenter mechanisms aligned along the bottom of said disk flip compartment; a plurality of holder mechanisms aligned along the bottom of said disk flip compartment opposing each of said plurality of presenter mechanisms; and a disk flipper mechanism having a disk holder rotatably attached to said disk flip compartment and positioned longitudinally between said plurality of presenter mechanisms and said plurality of holder mechanisms.

43. The apparatus of claim 42 wherein said presenter mechanism further comprises: a presenter base connected to the bottom of said disk flipper compartment and having a presenter protruding member and a presenter passageway extending completely through said presenter base and said protruding member; an upper presenter body slidably connected to said presenter protruding member; and a presenter tapered fitting attached to said upper presenter body at the end opposite said presenter base.

44. The apparatus of claim 42 wherein said holder mechanism further comprises:^" a holder base connected to the bottom of said disk flipper compartment and having a holder protruding member and a holder passageway extending completely through said holder base and said holder protruding member; an upper holder body slidably connected to said holder protruding member; and a holder tapered fitting attached to said upper holder body at the end opposite said holder base and having a spray nozzle attached thereto.

45. The apparatus of claim 44 wherein said upper holder body is stainless steel.

46. The apparatus of claim 45 wherein said disk holder further comprises a pair of disk holding fingers which hold said substrate by the outer edges of said substrate.

47. The apparatus of claim 41 wherein said orbiter further comprises: a motor which drives an-orbiter rotation gear; an orbiter shaft connected to an off-centered point on said orbiter rotation gear such that said orbiter shaft moves in an orbit upon rotation of said orbiter rotation gear, and having an upper end and a lower end; a solid connector bar which is fixedly connected to said lower end of said orbiter shaft and which is connected to said disk polish head; and an anti-rotation mechanism connected to said upper end of said orbiter shaft.

48. The apparatus of claim 47 wherein said disk polish head further comprises a fluid line containing a fluid connected to said disk polish head and openly terminating at the bottom surface of said disk polish head and connected at its other end to a reversible pump such that pressure or suction can be applied to said fluid in said fluid line.

49. The apparatus of claim 41 wherein said disk polish head further comprises an elliptical differential radius bearing.

50. The apparatus of claim 36 wherein said polishing means further comprises a removable conditioning roller for conditioning the polish media.

51. The apparatus of claim 50 wherein said removable conditioning roller is a nickel composite conditioning roller.

52. An apparatus for moving a cassette for holding a substrate and for moving a substrate without contacting the surface of said substrate comprising: a robot body attached to a horizontal drive screw assembly; a vertical drive screw assembly attached to said robot body; and an end effector attached to said vertical drive screw assembly and having a first passive finger for moving said substrate by only contacting an edge of said substrate and a cassette hook for lifting a cassette for holding said substrate.

53. The apparatus of claim 52 wherein said first passive finger fits inside of an opening defined by said substrate.

54. The apparatus of claim 53 further comprising a second passive finger opposing said first passive finger whereby said substrate can be moved to a station using said first passive finger and after releasing said substrate a second polished substrate can be retrieved from said station using said second passive finger.

55. An apparatus for receiving a substrate, presenting the substrate to a disk polish head and inverting a substrate comprising: a compartment; a presenter mechanism attached to the bottom of said disk flip compartment; a holder mechanism attached to the bottom of said disk flip compartment opposing said presenter mechanism; and a disk flipper mechanism having a disk holder and rotatably attached to said disk flip compartment and positioned to rotate back and forth between said presenter mechanism and said holder mechanism.

56. The apparatus of claim 55 wherein said presenter mechanism further comprises: a presenter base connected to the bottom of said compartment and having a presenter protruding member and a presenter passageway extending completely through said presenter base and said protruding member; an upper presenter body slidably connected to said presenter protruding member; and a presenter tapered fitting attached to said upper presenter body at the end opposite said presenter base.

57. The apparatus of claim 55 wherein said holder mechanism further comprises: a holder base connected to the bottom of said disk flipper compartment and having a holder protruding member and a holder passageway extending completely through said holder base and said holder protruding member; an upper holder body slidably connected to said holder protruding member; and a holder tapered fitting attached to said upper holder body at the end opposite said holder base and having a spray nozzle attached thereto.

58. An apparatus for imparting orbital motion to a disk polish head which retains a substrate to be polished comprising: a motor which drives an orbiter rotation gear; an orbiter shaft connected to an off-centered point on said orbiter rotation gear such that said orbiter shaft moves in an orbit upon rotation of said orbiter rotation gear, and having an upper end and a lower end; a solid connector bar which is fixedly connected to said lower end of said orbiter shaft and which is connected to said disk polish head; and an anti-rotation mechanism connected to said upper end of said orbiter shaft.

59. The apparatus of claim 58 further comprising: a plurality of motors which each drive a corresponding orbiter rotation gear; a plurality of orbiter shafts each connected to an off-centered point on each of said corresponding orbiter rotation gears such that each of said orbiter shafts moves in an orbit upon rotation of said corresponding orbiter rotation gear, and each having an upper end and a lower end; a plurality of solid connector bars each of which are fixedly connected at each of said lower ends of said plurality of orbiter shafts and which are each connected to said corresponding plurality of disk polish heads; and a plurality of anti-rotation mechanisms each connected to said corresponding upper end of each of said plurality of orbiter shafts.

60. An apparatus for retaining a substrate during polishing comprising: a seal plate; a disk plate attached to the bottom of said seal plate; a ring disk carrier attached to the bottom of said seal plate and about the circumference of said disk plate; and a plastic retainer ring attached to the bottom of said ring disk carrier and about the circumference of said disk plate.

61. The apparatus of claim 60 further comprising a diaphragm piston located between said seal plate and said disk plate.

62. The apparatus of claim 60 further comprising a diaphragm piston located between said seal plate and said ring disk carrier.

63. The apparatus of claim 60 further comprising a fluid line communicating with said seal plate and openly terminating at the bottom surface of said disk plate and communicating with a pump such that suction can be applied in said fluid line.

64. The apparatus of claim 60 further comprising a slurry line connected to said seal plate and openly terminating at the bottom surface of said disk plate and connected at its other end to a pump that supplies polishing slurry.

65. An apparatus for supplying web tape for polishing a substrate comprising: a supply roller having a roll of web tape; a take-up roller for collecting used web tape; wherein said supply and said take-up rollers are removable; and a removable conditioning roller, wherein said removable conditioning roller is a nickel composite conditioning roller.

66. An apparatus for sequentially polishing both sides of a substrate having a first side and a second side of similar dimensions and in approximately parallel planes comprising: a first robot comprising an orbiter for polishing a first side of a first substrate; a polish surface upon which said first robot polishes said first substrate; a flip station which receives said first substrate from said first robot after polishing said first side and which inverts said first substrate; and wherein said first robot transfers said first substrate having a first polished side from said polish station to said flip station and translates said first substrate from said flip station to said polish surface after said first substrate is inverted.

67. An apparatus according to claim 66 further comprising: a second robot for loading a cassette for holding said first substrate from a dry conveyor onto a shelf, moving said cassette from said shelf to a submerged shelf and unloading said cassette from said submerged shelf to a submerged conveyor.

68. An apparatus according to claim 66 further comprising: a second robot for conveying said first substrate from a shelf to said flip station, translating said first substrate from said flip station to said polish surface, transferring said first substrate having two polished sides from said polish station to said flip station and carrying said first substrate have two polished sides from said flip station to a submerged shelf.

69. The apparatus according to claim 68 wherein said second robot further comprises: a robot body attached to a horizontal drive screw assembly; a vertical drive screw assembly attached to said robot body; and an end effector attached to said vertical drive screw assembly and having a first passive finger for conveying, translating, transferring and carrying said first substrate which can be inserted into an opening defined by said first substrate thereby only contacting an edge of said first substrate and a cassette hook for lifting a cassette for holding said substrate.

70. The apparatus according to claim 69 further comprising a second passive finger opposing said first passive fmger whereby said cassette/disk handling robot can move said first substrate to said flip station using said first passive finger, retrieve a polished substrate from said flip station using said second passive finger as the next sequential step performed by said cassette/disk handling robot.

71. The apparatus according to claim 66 further comprising: a disk polish head attached to said orbiter for securing said first substrate when said first robot transfers said first substrate having a first polished side from said polish station to said flip station and when said first robot translates said first substrate from said flip station to said polish surface after said first substrate is inverted and for retaining said first substrate during polishing.

72. A computer program product for controlling an automated substrate polishing apparatus, the automated substrate polishing apparatus having a plurality of mechanical subsystems for achieving successive substrate polishing steps, comprising: a first computer code module for controlling a first mechanical subsystem that achieves a first substrate polishing step; and a second computer code module separate from said first computer code module for controlling a second mechanical subsystem that achieves a second polishing step responsive to the completion of-said first substrate polishing step; wherein said second computer code module actuates said second mechanical subsystem responsive to a global handshake received from said first computer code module; whereby said computer program product controls the automated substrate polishing apparatus in an event-oriented manner that does not require schedule-based control of successive mechanical subsystems of the automated substrate polishing apparatus.

73. The computer program product of claim 72, further comprising: computer code for maintaining a plurality of global variables accessible and changeable by each of said modules; wherein said global handshakes between modules are achieved by the polling and setting of at least one of said global variables.

74. The computer program product of claim 73, each of said modules being associated with a predetermined set of said global variables and being actuated responsive to a setting of a first subset thereof, each of said modules comprising: computer code for continuously polling said first subset of said predetermined set of global variables; and computer code for recognizing the setting of first subset of said predetermined set of global variables and actuating its associated mechanical subsystem responsive thereto.

75. The computer program product of claim 74, each of said modules further comprising: computer code for recognizing the completion of operation of its associated mechanical subsystem subsequent to said actuation; computer code for setting a second subset of said predetermined subset of said global variables for communicating to other modules the completion of the operation of the mechanical subsystem associated with that module.

76. The computer program product of claim 75, wherein the setting of said first subset of said predetermined global variables includes the step of setting said first subset to one of a plurality of control vector states, and wherein said module is capable of directing its associated mechanical subsystem to perform one of a plurality of different operations responsive to the control vector state of said first subset.

77. The computer program product of claim 76, wherein the setting of said second subset of said predetermined global variables includes the step of setting said second subset to one of a plurality of control vector states, responsive to which of said plurality of different operations is performed by its associated mechanical subsystem.

78. The computer program product of claim 77, further comprising computer code for providing a menu-driven user interface to said substrate polishing apparatus.

79. The computer program product of claim 78, said user interface including a recipe management screen for controlling parameters associated with the operation of at least one of said mechanical subsystems.

80. A method for calibrating a substrate polishing apparatus by computing transfer function constants, said transfer function constants for use by said polishing apparatus in computing a control pressure vector from a user-entered output vector during normal operation, comprising the steps of: applying a calibration set of control pressure vectors, said calibration set substantially spanning the space of possible control pressure vectors capable of being used in the operation of said polishing apparatus; measuring an actual output vector corresponding to each control pressure vector in said calibration set; and computing said transfer function constants using information derived from said actual output vectors and said calibration set of control pressure vectors.

81. The method of claim 80, said substrate polishing apparatus having a polishing head for uniformly applying a polishing pressure across the surface of a disk substrate, said step of measuring an actual output vector comprising the step of measuring point forces at locations corresponding to a plurality of points on said polishing head.

82. The method of claim 81, said substrate polishing apparatus having a polishing ring for restraining lateral movement of the disk substrate during polishing, said step of measuring an actual output vector further comprising the step of measuring point forces at locations corresponding to a plurality of points around said disk polish ring.

83. The method of claim 82, said step of computing said transfer function constants comprising the steps of: computing a first trial set of transfer function constants using two members of said calibration set of control pressure vectors and the two output vectors corresponding thereto; computing a second trial set of transfer function constants using two control pressure vectors, at least one of which is different than either of the two members used to compute said first trial set of transfer function constants, and the two output vectors corresponding thereto; and computing said transfer function constants using a statistical average of said first and second trial sets of transfer function constants.

84. The method of claim 83, said step of computing said transfer function constants comprising the steps of: computing an Nth trial set of transfer function constants using two control pressure vectors, said two control pressure vectors being a different combination than used in the computation of any other trial set of transfer function, and the two output vectors corresponding thereto; and computing said transfer function constants using a statistical average of said N trial sets of transfer function constants.

85. The method of claim 84, wherein each of said control pressure vectors comprises a ring control pressure and a disk control pressure.

86. The method of claim 85, wherein N is substantially equal to the maximum number of distinct combinations of two members that can be taken from said calibration set.

87. The method of claim 86, wherein said step of computing said transfer function constants comprises the step of weighting each trial set of transfer function constants prior to taking an arithmetic average thereof, said weights corresponding to a predetermined operational significance of the individual control pressure vectors used to calculate said trial sets of transfer function constants.

88. A portable calibration device for calibrating a plurality of substrate polishing machines each having at least one disk polish head, each of said substrate polishing machines being coupled to a local area network, said portable calibration device comprising: a frame for removable mechanical coupling to one of the substrate polishing machines near the polish head thereof; a sensor for measuring an output force and converting said measurement into digital form; and a digital input/output device for coupling to said local area network; wherein the local area network is used to communicate the measured output force to the substrate polishing apparatus producing that output force; whereby said portable calibration device can be used for a plurality of substrate polishing machines without requiring the establishment of a separate physical data link to each respective one of said substrate polishing machines.

89. The portable calibration device of claim 88, wherein said local area network is an ETHERNET network.

90. The portable calibration device of claim 88, each of said substrate polishing machines having a unique IP address, wherein said portable calibration device also has a unique IP address, and wherein said portable calibration device communicates with said substrate polishing machines using a TCP/IP protocol.