US20110097977A1

US20110097977A1 - Multiple-sided cmp pad conditioning disk

Info

Publication number: US20110097977A1
Application number: US12/537,456
Authority: US
Inventors: Mark L. Bubnick; Thomas S. Namola, JR.
Original assignee: Abrasive Technology Inc
Current assignee: Abrasive Technology Inc
Priority date: 2009-08-07
Filing date: 2009-08-07
Publication date: 2011-04-28
Also published as: KR20110015402A; TW201116364A; KR101156862B1

Abstract

A conditioning tool for restoring a used CMP polishing pad to an operable condition. The tool includes a base that attaches to a driven machine and has a surface from which a shoulder protrudes that receives a peripheral edge of a disk. The disk has two opposing surfaces, each of which is substantially planar and has abrasive mounted thereon. The disk's peripheral edge is held in place between the base shoulder and a ring that has a shoulder that is complementary to the disk's peripheral edge. The ring is fastened to the base with the abrasive of the first disk surface protruding through an aperture in the ring, and the opposing disk surface spaced from the base's surface. After the disk's first surface is worn, the disk can be turned around to expose the opposite surface's abrasive to a CMP pad.

Description

BACKGROUND OF THE INVENTION

1. Field Of The Invention
This invention relates generally to methods and apparatuses related to the polishing of workpieces, such as semiconductor wafers, and particularly to an improved disk or other shape substrate for conditioning and restoring polishing pads used in such methods.
2. Description Of The Related Art
The production of integrated circuits involves the manufacture of high quality semiconductor wafers. As well known in this industry, a surface that is flat (planar) to a high degree of precision is required on at least one side of the wafer to ensure that appropriate performance objectives are achieved. As the size of the circuit components decreases and the complexity of the microstructures involved increases, the requirement for high precision surface qualities of the wafers increases.
This high precision surface is formed on semiconductor wafers by the polishing or planarization of semiconductor wafers. During this process, a polishing pad is rotated against a surface of the wafer in the presence of an abrasive slurry. The chemical components of the abrasive slurry react with one or more particular materials on the wafer being polished and aid the abrasive in removing portions of this material from the wafer's surface. The typical polishing pad comprises a blown polyurethane-based material such as the IC and GS series of pads available from Rohm and Haas. The hardness and density characteristics of the polishing pads are determined on the basis of the material of the workpiece (semiconductor wafer) that is to be polished.
The following patents provide a broad discussion of chemical, mechanical planarization, which is referred to herein, and in the industry, as CMP: Arai et al. U.S. Pat. No. 4,805,348 issued February, 1989; Arai et al. U.S. Pat. No. 5,099,614 issued March, 1992; Karlsrud et al. U.S. Pat. No. 5,329,732 issued July, 1994; Karlsrud et al. U.S. Pat. No. 5,498,196 issued March, 1996; Karlsrud et al. U.S. Pat. No. 5,498,199 issued March, 1996; Cesna et al. U.S. Pat. No. 5,486,131 issued January, 1996; and Holzapfel et al. U.S. Pat. No. 5,842,912 issued Dec. 1, 1998. All of the foregoing patents are incorporated herein by reference.
During continued use of the polishing pad in the CMP process, the rate of material removal from the wafer gradually decreases due to what is referred to in this field as “pad glazing”. Additionally, with continued use, the surface of the polishing pad normally experiences uneven wear which results in undesirable surface irregularities. Therefore, it is necessary to recondition (true and dress) the polishing pad to restore it to a desirable operating condition by exposing the pad to a pad-conditioning surface, such as the planar surface of a rotating disk, having suitable cutting elements on it. This truing and dressing of the pad may be accomplished during the wafer polishing process (referred to as in-situ conditioning) such as described in U.S. Pat. No. 5,569,062 issued on Oct. 29, 1996 to Karlsrud. However, such conditioning may also be done between polishing steps (referred to as ex-situ conditioning) such as described in U.S. Pat. No. 5,486,131 issued on Jan. 23, 1996 to Cesna et al., both of these patents being incorporated by reference herein.
Reconditioning of a polishing pad restores the appropriate frictional coefficient of the pad surface and thereby allows the pad to continue to be used to provide the desired flat surface on the wafers. Reconditioning also allows effective transport of the polishing slurry to the wafer surfaces in order to obtain the most effective and precise planarization of the semiconductor wafer surface being polished.
The typical pad conditioner comprises a stainless steel disk coated with a monolayer of abrasive particles. The disk is mounted to a rotary motor and the abrasive particle-coated surface is placed against the CMP pad when the surface is being rotated. Diamond particles or cubic boron nitride particles are the preferred abrasives, and are often referred to as “superabrasives” due to their resistance to wear. These superabrasive particles may be secured to the conditioning disk by electroplating, sintering or by a brazing process. The brazing process is preferred due to the formation of a stronger bond between the particles and the substrate, thereby resulting in the particles being less likely, compared to electroplated conditioning disks, to loosen and fall free. If abrasive particles fall free and become embedded in the polishing pad or are otherwise exposed to the wafer being polished, significant deformations in, or abrasions of, the wafer surface may occur that could cause the wafer to be unusable. Such a situation represents a loss of many thousands of dollars of time and labor.
Conditioning disks employing a monolayer of braze bonded diamonds, such as those manufactured by Abrasive Technology, Inc. of Lewis Center, Ohio, have been recognized as very effective and an improvement over prior art conditioning disks using other bonding mediums, particularly in resisting premature loss of diamond abrasive particles. Current art for restoring used CMP polishing pad uses a diamond conditioning disk with a diamond surface on one side of the conditioning disk and a mounting surface on the opposite side of the disk to attach the conditioning disk to the conditioning drive mechanism.
Some devices used for lapping, such as double-sided lapping, could appear to be related to devices used to restoring used CMP pads. Such devices, which are believed to be manufactured by Lap Master and possibly others, are inserted between oppositely-rotated platens and float therein during opposing rotation. Such devices are not driven directly as CMP reconditioning disks must be in typical CMP reconditioning processes due to the fact that CMP polishing pads recondition only one side of a surface at a time. CMP pads are not used to polish two sides of a surface as in the lapping process.
Therefore, the need arises for a conditioning disk that reduces the amount of material used and thereby reduces the cost of the conditioning disk without any reduction in performance.

BRIEF SUMMARY OF THE INVENTION

The invention provides a conditioning tool for restoring a used CMP polishing pad to an operable condition. In a preferred embodiment, the invention includes a substrate, which is preferably a disk having a circular peripheral edge. In a preferred embodiment, the peripheral edge of the disk is beveled with at least two surfaces at an angle with one another.
The disk has a first substantially planar surface to which a first abrasive, such as a monolayer of diamond particles, is attached, such as by brazing. A second abrasive is attached in a similar manner to a second, opposing substantially planar surface. This configuration thereby forms two opposing, substantially planar abrasive surfaces that are used, at different times, for reconditioning a used CMP polishing pad.
A base, which is for drivingly linking the tool to a rotatably driven machine, has a circular shoulder extending from a base surface. The base shoulder diameter is preferably substantially equal to a diameter of the circular peripheral edge of the disk. The base shoulder receives at least a portion of the peripheral edge of the disk, and most preferably receives one of the angled surfaces of the peripheral edge.
A fastener, such as a screw or magnets, mounts the disk to the base. The first abrasive faces away from the base, and the second abrasive is spaced from the base surface so that no wear is experienced by either the second abrasive or the base surface due to contact.
In a preferred embodiment, a ring has an annular body with a circular shoulder defining an aperture. The aperture has a diameter that is smaller than the diameter of the peripheral edge of the disk to prevent passage of the entire disk through the aperture. The ring shoulder diameter is substantially equal to the diameter of the peripheral edge of the disk, and the ring shoulder receives at least a portion of the peripheral edge of the disk.
A fastener, such as a screw or magnets, mounts the ring to the base with the disk held between the ring and the base by a clamping force. The clamping force is preferably applied only to the peripheral edge of the disk by the ring shoulder and the base shoulder. The first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface so that no wear is experienced by either the second abrasive or the base surface due to contact.
Thus, in one embodiment of the invention, the base has a disk mounted to it, wherein the disk has abrasive on two opposing sides. The disk is flipped around when the abrasive on one side approaches or reaches the end of its useful life. The disk can be mounted to the base by fastening means, which can include any useful fastener. In the preferred embodiment, the fastening means includes a ring that is slightly larger than the disk, with an aperture through which the abrasive on the disk protrudes, that clamps the disk between the ring and the base. In one particular embodiment, the disk has peripheral edges that are advantageously contacted by the ring and the base, thereby avoiding mounting contact with the abrasive portions of the disk. The peripheral edges of the disk and the receiving surfaces of the base and ring align and retain the disk.
The invention thus effectively provides two useful abrasive conditioning surfaces per disk instead of the current industry standard practice of one, among other advantages and improvements.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a top view illustrating a preferred embodiment of the present invention.

FIG. 2 is a bottom view illustrating a preferred embodiment of the present invention.

FIG. 3 is a side view in section illustrating the embodiment of FIGS. 1 and 2 through the line 3-3 of FIG. 1.

FIG. 4 is a view in perspective illustrating the embodiment of FIG. 3.

FIG. 5 is a view in perspective illustrating the preferred disk of the present invention.

FIG. 6 is a close-up view illustrating the disk of FIG. 5.

FIG. 7 is a view in perspective illustrating the preferred ring of the present invention.

FIG. 8 is a side magnified view in section of the encircled portion of the preferred embodiment of the present invention shown in FIG. 3.

FIG. 9 is a perspective view in section with the base removed to illustrate the notches in the disk and the ring.

FIG. 10 is a top view of the invention shown in FIG. 9 showing the position of the complete key in the notches, which are only shown in part due to the section view.

FIG. 11 is a view in perspective illustrating an alternative embodiment of the present invention.

FIG. 12 is a side view in section illustrating the embodiment of FIG. 11 in section through the line 12-12.

FIG. 13 is a perspective view in section illustrating the embodiment of FIG. 11 in section through the line 12-12.

FIG. 14 is a perspective view in section illustrating the embodiment of FIG. 11 in section through the line 14-14.

FIG. 15 is a view in perspective illustrating the device of FIG. 14 with several pieces removed for illustrative purposes.

FIG. 16 is a view illustrating the device of FIG. 15 with additional pieces removed.

FIG. 17 is a view illustrating the device of FIG. 11 with several pieces removed for illustrative purposes.

FIG. 18 is a view illustrating the device of FIG. 17 with additional pieces removed.

FIG. 19 is a view in perspective illustrating an alternative embodiment of the present invention.

FIG. 20 is a view in perspective illustrating the embodiment of FIG. 19 from the underside.

FIG. 21 is a side view in section illustrating the embodiment of FIG. 20 through the lines 21-21.

FIG. 22 is a perspective view in section illustrating the embodiment of FIG. 20 through the lines 21-21.

FIG. 23 is a perspective view in section illustrating the embodiment of FIG. 22 with several pieces removed for illustrative purposes.

FIG. 24 is a view in perspective illustrating an alternative embodiment of the present invention.

FIG. 25 is a side view in section illustrating an alternative embodiment of the present invention.

FIG. 26 is another side view in section illustrating the embodiment of FIG. 25 with portions removed for clarity.

FIG. 27 is a lower section view in perspective illustrating the embodiment of FIG. 25.

In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word connected or terms similar thereto are often used. They are not limited to direct connection, but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiment of the present invention includes the following major components that are illustrated in FIGS. 1-10. A holder 10 is made up of a base 20 and a ring 30 that attaches to the base 20. The base 20 is designed to be attached to a drive mechanism (not shown), such as a rotatable drive motor. The ring 30 rigidly and firmly attaches to the base 20 using fasteners, such as screws or magnets. A disk 40 is mounted between the ring 30 and the base 20, and is held in place in a tight, non-rotatable connection preferably by structures located at the peripheral edge of the disk 40 and the ring 30 or base 20 that interlock to prevent relative movement of the disk 40 and the holder 10. In this manner, the disk 40 is held firmly in place in the holder 10, and is driven rotatably thereby without substantial relative rotational movement between the disk 40 and the holder 10. This permits the disk surface to be placed in contact with a CMP polishing pad for conditioning the pad, which is the purpose of the apparatus.
The pad conditioning substrate, such as the disk 40 in particular, is best shown in FIGS. 2, 3 and 5 having a generally planar shape with two opposing, substantially planar major faces 42 and 44. The major surfaces 42 and 44 of the disk are preferably parallel and substantially flat for reasons that will become apparent below. Upon the planar major surfaces 42 and 44 an abrasive, and preferably conventional superabrasive particles, such as diamond, cubic boron nitride, silicon carbide, alumina or any other conventional superabrasive, is attached in a conventional manner, such as by brazing, electroplating or adhesively mounting as described in the United States patents incorporated herein by reference and as known conventionally. The abrasive particles are preferably about 30 to about 350 microns, depending upon the type of CMP the disk will be used for. Thus, these particles are not visibly distinct in the illustrations. The abrasive can be in a pattern, and can be over most of the surface of the major faces 42 and 44, or only over a small portion thereof, such as in the case of a ring-shaped circle of abrasive. Thus, each of the major faces 42 and 44 has at least a portion of its surface covered by a single layer of abrasive to enable the faces 42 and 44 to abrade any workpiece surface against which they are placed in contact during rotation.
Because the disk 40 can be used as a CMP pad conditioning disk, the portion of the faces 42 and 44 that is covered by abrasive does not extend to the peripheral edge of the disk 40. Instead, according to industry practice, a small gap is formed between the radially outermost edge of the abrasive and the extreme peripheral edge of the disk 40.
The disk 40 is preferably made of a strong, corrosion-resistant material, such as stainless steel, titanium, ceramic or plastic and has substantial thickness, on the order of 5.0 mm, to prevent substantial deformation when in use. The diameter of the disk 40 can be on the order of 10.5 cm. These sizes and materials are examples for the purpose of explanation; the size and material of the disk are not critical and can vary substantially from these examples. Preferably the base 20 and the ring 30 are also made of stainless steel or any other material that is compatible with the circumstances.
As best viewed in FIG. 6, the disk's peripheral edge 45 is preferably beveled to form three circular surfaces 46, 48 and 49 extending around the periphery of the disk 40 and formed at angles with one another. The relative angle α between the two surfaces 46 and 48 is not critical, but is preferably in the range of about 90 degrees. The circular surfaces 46 and 48 are preferably angled relative to the surfaces 42, 44 and 49 of the disk 40 by about 45 degrees, and the surface 49 is angled relative to the major surfaces 42 and 44 by about 90 degrees. These angles can vary significantly. For example, the angle α can vary from 90 degrees, and it is contemplated that the angle α can range from at least about 30 degrees to about 180 degrees.
When the angle α is 180 degrees, the peripheral edge 45 is flat; that is, the edge 45 defines a single curved, circular surface angled at ninety degrees from the major surfaces 42 and 44 of the disk. Although this embodiment is not illustrated, such a disk has a configuration resembling a conventional coin. In another alternative disk 340 shown in FIG. 24, the peripheral edge 345 is rounded. Other shapes are also contemplated. The peripheral edge of the disk can be any non-perpendicular shape that protrudes to permit gripping, and with some fastening means, a perpendicular shape is useful. Virtually any shape that permits the invention to function as described herein can be substituted for the peripheral edge shapes described herein.
The base 20 is shown in FIG. 1 having a substantially circular cylindrical configuration. This is preferred, but not required, and it will become apparent to the person of ordinary skill that the base 20 can be any shape that can be driven in rotation, preferably at high speed, without imbalance and without negatively affecting surrounding structures. The base 20 has a first end 22 in which are formed voids, such as the threaded bores 23, that permit convenient attachment of a drive mechanism, as is conventional. Examples of typical CMP conditioning machines used in the industry are the AMAT Mirra and Reflection tools and CMP machines sold by Ebarra Technologies. Other drive mechanisms can be substituted with modifications to the base and/or the drive mechanism that will be understood by the person having ordinary skill. The base 20 is preferably mounted to the drive mechanism using screws (not shown) threaded into the bores 23, although other fasteners will become apparent to the person having ordinary skill, including without limitation, a conventional tool “chuck” that radially grips a shaft, a magnetic attachment or an o-ring that is compressed and then expands into an annular groove.
A second base end 24 (see FIGS. 3 and 4), which is opposite the first base end 22 to which the drive mechanism mounts, has a first surface 25 that is preferably substantially planar. A shoulder 26 is formed integrally with the base 20 (see FIG. 8), although it could be mounted on the first surface 25 as a separate piece. The shoulder 26 has an inwardly facing surface 28 that is angled at about 45 degrees from the first surface 25. The inwardly facing surface 28 is of a size, shape and orientation to abut the angled surface 46 of the disk's peripheral edge 45, as shown in FIG. 8.
The ring 30 has a circular body 31 with an aperture 35 formed through the body 31. The aperture 35 is defined by the radially inwardly extending shoulder 36 that is most easily seen in FIG. 8. The shoulder 36 has a surface 38 that is oriented from the surface 39 at an angle of about 45 degrees. The aperture 35 extends between the radially inward-most edge of the shoulder 36, and is preferably slightly smaller in diameter than the diameter of the disk 40 so that the disk 40 cannot pass completely through the aperture 35.
The ring 30 mounts to the base 20 by at least one fastener, such as the screws 32, 33 and 34, shown in FIG. 1. The screws 32-34 extend through the aligned apertures extending between the ring 30 and the base 20, an example of which is the aperture 50 shown in FIG. 8. When the ring 30 is mounted to the base 20, as shown in detail in FIG. 8, the disk 40 is clamped between the ring 30 and the base 20 as will now be described.
It is preferred that when the disk 40 is clamped between the base 20 and the ring 30, the only surfaces in contact between the three respective bodies are the surfaces at the periphery of the disk 40 as shown clearly in FIG. 8. Thus, the surface 28 of the body 20 firmly abuts the surface 46 of the disk 40. The surface 38 of the ring 30 applies an opposing abutting force against the surface 48 of the disk 40. The clamping force of the ring 30 and the base 20 against the peripheral edge surfaces of the disk 40 retains the disk 40 in place in such firm engagement that no substantial movement of the disk 40 relative to the holder 10 is possible under contemplated conditions when the holder 10 is driven in rotation. Furthermore, the engagement of the beveled peripheral edge 45 of the disk 40 with the complementary surfaces of the base 20 and ring 30 ensure that, even if the disk 40 is not initially resting in such a position, the fastening of the ring 30 to the base 20 causes the angled surfaces of the disk 40 to slide against the abutting surfaces until the disk 40 “seeks” the relative position between the two structures in which the disk 40 is as close to the base 20 as possible.
The disk 40 is also restricted from moving rotationally relative to the holder 10 by a key 57 that extends into the aligned notches 37 and 47 (see FIGS. 6, 7 and 10) formed in the ring 30 and the peripheral edge 45 of the disk 40, respectively. As shown in FIG. 9, the notches 37 and 47 align with one another to form a void that is substantially the same shape as the key 57. The key 57 is preferably slightly smaller than the notch 47, and slightly larger than the notch 37 so that the key 57 is inserted into and held in the notch 37 with a friction fit. The key 57 thus remains attached to the ring 30, and extends into the notch 47 of the disk 40 upon alignment of the notch 47 with the protruding portion of the key 57. The disk 40 can then be removed by manually lifting the disk 40 from the base 20 and ring 30.
It should be understood that although the invention shows a single key 57, it is contemplated that more than one such key can be used, and that the shape of the key can be varied from that shown. For example, the key can be circular, rectangular, triangular, dovetail or any other shape that is suitable. In an alternative embodiment, the key 57 is replaced by a magnet that has such strong attraction to the disk itself, or a structure mounted in the disk or another structure, that any expected rotational force applied to the disk 40 by the workpiece is insufficient to cause relative motion.
A gap 60 (FIG. 8) is formed between the major disk surface 42 and the surface 25 on the base 20. The gap 60 prevents the abrasive on the major disk surface 42 from contacting the surface 25 on the base 20, and thereby causing wear between the two parts. Furthermore, the major disk surface 44 protrudes through the aperture 35 of the ring 30, and extends past the extreme surface 39 of the ring 30, as best viewed in FIG. 8. The extension of the major disk surface 44 past the ring surface 39 prevents the ring 30 from contacting the surface that is to be conditioned by the abrasive on the major disk surface 44.
The invention operates in a preferred embodiment in the following manner. The base 20 is mounted to the driving machine and the disk 40 is placed in the ring 30. The ring 30 and the disk 40 are placed under the base 20 (with the notch 47 aligned with the notch 37 and the key 57 inserted in the notches 37 and 47 as described herein) and the screws 32-34 are inserted and tightened in the apertures. Upon tightening, the disk 40 is clamped in place between the ring 30 and base 20, and the angled peripheral surfaces 46 and 48 are seated against the angled surfaces 28 and 38 of the base 20 and ring 30, respectively.
Once the disk 40 is mounted to the holder 10, the holder 10 and the disk 40 are rotated. The rotating major disk surface 44 is seated against one or more CMP polishing pads and the CMP pads are reconditioned as is conventional. Once the abrasive on the major disk surface 44 reaches a predetermined degree of wear, the rotating machine is halted and the ring 30 is removed from the base 20 by removing the screws 32-34 and manually pulling the ring 30 and the disk 40 away from the base 20, typically as a combination. Once the ring 30 and disk 40 are removed from the base 20, the disk 40 can be removed manually from the ring 30 by simply pulling the disk 40 away from the ring 30.
The removed disk 40 is then flipped so that the worn major disk surface 44 faces toward the base 20 and the fresh major disk surface 42 faces away from the base 20. Of course, the entire apparatus, including the disk, can first be cleaned, if necessary. In one contemplated embodiment, a film, coating or other indicator of whether a major disk surface has been used is fixed to the surface to make instantly recognizable whether the major disk surface 42 has been used. The disk's notch 47 is aligned with the notch 37 and key 57, and the ring 30 is then reattached to the base 20 in the same way it was attached previously. This forms a gap between the major disk surface 44 and the base surface 25 that is essentially identical to the gap 60. The holder 10 and the disk 40 are rotated and the major disk surface 42 is seated against one or more CMP polishing pads so the CMP pads can be reconditioned.
The invention permits only one abrasive surface of the disk 40 to be used at any time. This is due to the fact that the holder 10 substantially covers all other sides of the disk 40 when the disk 40 is being rotated in contact with a workpiece. Furthermore, because of the gap 60, the use of one abrasive surface has little to no effect on the opposing abrasive surface, because little to no wear occurs to the abrasive surface that is not in use or to its adjacent structure.
It will become apparent from the description herein that various substitutes can be made for the preferred structures and methods described herein. For example, the fasteners used to mount the ring 30 to the base 20 are preferably screws, because screws facilitate the removal and replacement of the disk 40 from the base 20 numerous times using common tools. However, other removable fasteners can be used instead of the screws 32-34, including without limitation, magnetic fasteners, rivets, clamps and specialized structures made for the purpose of fastening the ring to the base or any combination of these or equivalents. Similarly, although the base 20 is shown attached to the driving machine by threaded apertures 23 formed therein, the person having ordinary skill knows that such fastening means can likewise be replaced by a single threaded chuck, clamps, and other fastening means. Furthermore, sealing structures can be added to prevent the slurry from leaking into the holder 10. For example, compressible O-rings or adhesive-backed plastic gaskets can be inserted between the ring 30 and the base 20, as well as between the disk 40 and the base 20 and between other structures.
In addition, the shape of the disk 40, ring 30 and base 20 can be modified from the preferred embodiment shown in FIGS. 1-9. For example, the base can be square or triangular in section rather than circular. Similarly, the ring and disk can have different shapes, preferably to accommodate the shape of the cooperating components, and to permit rotation of the holder and disk without excessive vibration.
One distinct advantage of the invention is that it is manufactured to be very similar in material and size to existing one-sided disks, and therefore can be used in existing machines, but there is abrasive on both sides instead of only one side. This permits the subsequent use of a second side of the disk without substantial added material costs in the underlying substrate (disk). Similarly, the only portion of the abrasive device that must be either discarded or recycled after use is the component that seats directly against the surface to be abraded. Because the holder 10 is re-used, costs over conventional one-sided disks are lower in the long term.
Another advantage of the invention is the reduced time required to change a disk. The holder 10 does not have to be removed from the machine that drives the holder. Instead, the holder remains in the driver and a few small screws are removed and then replaced after rotation of the disk to expose the unused side. Still further, when it is desired to expose a new abrasive surface in any holder that is using a disk with an unused abrasive surface, this can be accomplished without having to locate another disk. Instead, a fresh disk is retained within the holder 10.
It is also contemplated that instead of a disk with only two sides, other substrate shapes can be used. For example, a stainless steel cube is contemplated having six planar sides and between two and six abrasive surfaces. Each side has a monolayer of superabrasive extending to near the edges thereof. A base has a shoulder with a square-shaped surface that seats against the cube. A square ring with a similar shoulder around an aperture that is slightly smaller than each of the cube's sides is mounted to the base, thereby clamping the cube to the base. The base, ring and cube are mounted to a device that rotates the combination and the protruding surface of the cube abrades the workpiece. Upon reaching a certain point of wear, the cube is removed and moved to expose a different, unused abrasive surface of the cube through the aperture in the ring by removing the ring and then replacing the ring after movement of the cube. Alternative shapes are also contemplated.
The abrasive characteristics of each side of a substrate are preferably substantially the same. However, it is contemplated that the abrasive on one side can differ slightly or substantially from the abrasive on the opposing side. Additionally, with a multi-sided substrate each side can differ so that, for example, each abrasive can be used for a portion of a polishing procedure on a workpiece. In a contemplated example, a coarse abrasive is used first, and then a more fine abrasive, and then a still finer abrasive.
Another alternative embodiment of the invention is shown in FIGS. 11-18. In FIG. 11, a holder 110 is made up of a base 120 and a ring 130 that attaches to the base 120. The base 120 is designed to be attached to a drive mechanism (not shown), such as a rotatable drive motor. The ring 130 rigidly and firmly attaches to the base 120 using fasteners, such as screws or magnets. A disk 140 is mounted to the ring 130, and held in place in a tight, non-rotatable connection preferably by structures located at the peripheral edge of the disk 140 and the ring 130 or base 120 that interlock to prevent relative movement of the disk 140 and the holder 110. In this manner, the disk 140 is held firmly in place in the holder 110, and is driven rotatably thereby without substantial relative rotational movement between the disk 140 and the base 120.
The disk 140 is substantially the same as the disk 40 shown and described herein. The base 120 is shown in FIG. 11 having a substantially circular cylindrical configuration, which is preferred. The base 120 has a first end 122 (see FIG. 12) in which are formed voids, such as the threaded bores, that permit convenient attachment of a drive mechanism, as is conventional. The base 120 is preferably mounted to the drive mechanism in a conventional manner.
A second base end 124 (see FIG. 12), which is opposite the first base end 122 to which the drive mechanism mounts, has a first surface 125 that is preferably substantially planar. The ring 130 has a circular body with an aperture formed through the body. The aperture is defined by the shoulder 136 that forms a disk-shaped void that seats against the peripheral edge of the disk 140. The shoulder 126 of the ring 130 opposes the shoulder 136 and forms a groove therebetween into which the peripheral edge of the disk 130 is inserted during use. The aperture 135 extends between the radially inward-most edge of the shoulder 136, and is preferably slightly smaller in diameter than the disk 140 so that the disk 140 cannot pass completely through the aperture 135. Thus, the shoulders 126 and 136 of the ring 130 form surfaces that seat against the peripheral edge of the disk 140 much like the shoulders 26 and 36 of the embodiment shown in FIGS. 1-10. However, because the shoulders 126 and 136 are not moveable relative to one another, there is not a similar adjustable clamping, and there must be separable portions of the ring to permit insertion and removal of the disk 140.
The ring 130 mounts to the base 120 by at least one fastener, such as the screws 132, and 134, shown in FIG. 11. It is preferred that when the disk 140 is mounted in the ring 130, the only surfaces in contact between the three respective bodies are the surfaces at the periphery of the disk 140 as with the embodiment of FIGS. 1-10. In order to mount the disk 140 in the ring 130, the first portion 130 a (see FIGS. 15 and 16) is separated from the second portion 130 b, such as by removing fasteners from voids in the ends of the portions 130 a and 130 b. Thus, the second portion 130 b can be mounted permanently to the base 120, the disk 140 slid into the groove defined by the shoulders 136 and 126, the first portion 130 a is slid over the end of the disk 140, and then the fasteners 132 and 134 are fixed between the base 120 and the ring 130.
The disk 140 is restricted from moving rotationally relative to the holder 110 by a key 157 (see FIGS. 13, 17 and 18) that extends into aligned notches formed in the ring 130 and the peripheral edge of the disk 140. A gap 160 (FIG. 12) is formed between the major disk surface 142 and the surface 125 on the base 120. The gap 160 prevents the abrasive on the major disk surface 142 from contacting the surface 125 on the base 120, and thereby causing wear between the two parts. Thus, the holder 110 has many of the same features of the embodiment of FIGS. 1-10, thereby demonstrating the variability of the embodiments of the present invention.
Another alternative embodiment of the invention is shown in FIGS. 19-23. The holder 210, which attaches to a drive mechanism as with the other embodiments disclosed herein, has a disk 240 attached to a base 220 by fastening means, such as the screws 232 and 234, as shown in FIG. 21. Of course, other fasteners and fastening means could be substituted for the screws 232 and 234, including without limitation magnets, press-fit pins, rivets and clamps or a combination. For example, a contemplated combination includes a magnetic attraction between a disk and base combined with one or more drive pins that extend from the base into corresponding voids in the disk to prevent relative rotation. A base surface 225, which is preferably planar, is formed on one end of the base 220. A first disk-receiving surface is formed on the shoulder 236 extending from the surface 225. A second disk-receiving surface is formed on an opposing shoulder 226. Complimentary surfaces are formed on the disk 240 at the peripheral edge thereof and at the transition between the central region 250 and the abrasive surface 252.
When the disk 240 is mounted to the base 220, these complimentary surfaces permit the shoulders 236 and 226 of the base 220 to contact the disk 240 where there are no abrasive particles. Thus, when the screws 232 and 233 are tightened against the central region 250 of the disk 240, the opposite side of the disk 240 seats against the base 220, but a gap is formed between the abrasive surface and the disk's surface 225. Of course, the peripheral edge of the disk 240 need not be beveled. Instead, the peripheral edge can be angled at 90 degrees from the major surfaces of the disk.
Another alternative embodiment of the invention is shown in FIGS. 25-28. In FIG. 25, a holder 410 is made up of a base 420 and a ring 430 that attaches to the base 420. The base 420 is designed to be attached to a drive mechanism (not shown). The ring 430 rigidly and firmly attaches to the base 420 using fasteners, such as screws or magnets (not shown). A disk 440 is mounted to the ring 430, and held in place in a tight, non-rotatable connection preferably by structures located at the peripheral edge of the disk 440 and the ring 430 or base 420 that interlock to prevent relative movement of the disk 440 and the holder 410. In this manner, the disk 440 is held firmly in place in the holder 410, and is driven rotatably thereby without substantial relative rotational movement between the disk 440 and the base 420. The disk 440 is substantially the same as the disk 40 shown and described herein, except for the peripheral edges.
As best viewed in FIGS. 25 and 26, the disk 440 has a peripheral edge 445 that is beveled to form three circular surfaces 446, 448 and 449 extending around the periphery of the disk 440 and formed at angles with one another. The relative angle between the two surfaces 446 and 448 is not critical, but is preferably in the range of about 90 degrees. The surfaces 446 and 448 are preferably angled relative to the opposing disk surfaces 442 and 444 and the peripheral edge surface 449 of the disk 440 by about 45 degrees. Furthermore, the surface 449 is angled relative to the surfaces 442 and 444 by about 90 degrees. These angles can vary significantly as with the embodiments described above.
The base 420 is shown in FIG. 25 having a substantially circular cylindrical configuration, which is preferred. The base 420 has a first end in which are formed voids, such as the threaded bores, that permit convenient attachment of a drive mechanism, as is conventional. The base 420 is preferably mounted to the drive mechanism in a conventional manner. A base end 424 (see FIG. 25), which is opposite the base end to which the drive mechanism mounts, has a first surface 425 that is preferably substantially planar.
The ring 430 has a circular body with an aperture formed through the body. The aperture is defined by the shoulder 436 that forms a disk-shaped void that seats against the peripheral edge 449 of the disk 440. The shoulder 436 defines a rib that is inserted in the groove, formed at the peripheral edge of the disk 430, during use (as shown in FIG. 25). The aperture in the ring 430 extends between the radially inward-most edge of the shoulder 436, and is preferably slightly smaller in diameter than the disk 440 so that the disk 440 cannot pass completely through the aperture. Thus, the shoulder 436 forms a surface that seats against the peripheral edge 445 of the disk 440 much like the shoulders 26 and 36 of the embodiment shown in FIGS. 1-10. However, because there is not a similar adjustable clamping as in the FIGS. 1-10 embodiment, there must be separable portions of the ring 430 to permit insertion and removal of the disk 440.
The ring 430 mounts to the base 420 by at least one fastener, such as screws (not illustrated). It is preferred that when the disk 440 is mounted in the ring 430, the only surfaces in contact between the three respective bodies are the surfaces at the periphery of the disk 440 as with the embodiment of FIGS. 1-10. In order to mount the disk 440 in the ring 430, the first portion 430 a (see FIG. 28) is separated from the second portion 430 b, such as by removing fasteners from voids in the ends of the portions 430 a and 430 b. Thus, the second portion 430 b is mounted permanently (or removably) to the base 420, the disk 440 is slid into the ring portion 430 b, the first portion 430 a is slid over the end of the disk 440, and then the fasteners are fixed between the base 420 and the ring 430.
The disk 440 is restricted from moving rotationally relative to the holder 410 by a key 457 (see FIG. 25) that extends into aligned notches formed in the ring 430 and the peripheral edge of the disk 440. A gap 460 (FIG. 25) is formed between the major disk surface 442 and the surface 425 on the base 420. The gap 460 prevents the abrasive on the major disk surface 442 from contacting the surface 425 on the base 420, and thereby causing wear between the two parts.
This detailed description in connection with the drawings is intended principally as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention and that various modifications may be adopted without departing from the invention or scope of the following claims.

Claims

1. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(a) a substrate having a peripheral edge and a first substantially planar major surface with a first abrasive mounted thereon and at least a second, oppositely facing, substantially planar major surface with a second abrasive mounted thereon;

(b) a base for drivingly linking to a rotatably driven machine, the base having a base surface; and

(c) at least one fastener mounting the substrate to the base with the second abrasive spaced from the base surface to form a gap between the base surface and the second abrasive, and the first abrasive facing away from the base.

2. The conditioning tool in accordance with claim 1, wherein said at least one fastener is mounted at a central region of the substrate and the base, wherein said central region of the substrate has no abrasive mounted thereon.

3. The conditioning tool in accordance with claim 2, wherein said at least one fastener extends through the substrate into the base.

4. The conditioning tool in accordance with claim 1, wherein the substrate is a disk with a circular peripheral edge.

5. The conditioning tool in accordance with claim 4, wherein said at least one fastener mounts a ring to the base with the disk held between the ring and the base by a clamping force applied to the disk, the first abrasive protrudes through an aperture of the ring that is smaller than the disk, the base has a first substrate-shaped void in which the substrate is mounted and the ring has a second substrate-shaped void in which the disk is mounted.

6. The conditioning tool in accordance with claim 5, wherein the first substrate-shaped void is defined by a circular shoulder extending from the base surface, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk.

7. The conditioning tool in accordance with claim 6, wherein the second substrate-shaped void is defined by a ring body having a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk.

8. The conditioning tool in accordance with claim 7, wherein said at least one fastener mounts the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder.

9. The conditioning tool in accordance with claim 8, further comprising a key inserted into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

10. The conditioning tool in accordance with claim 4, wherein said at least one fastener mounts a ring to the base, a groove in the ring defining first and second substrate-shaped voids retains the disk in the ring, and the first abrasive protrudes through an aperture of the ring that is smaller than the disk.

11. The conditioning tool in accordance with claim 10, wherein the first substrate-shaped void is defined by a first circular shoulder formed in the ring, a first shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk, and wherein the second substrate-shaped void is defined by a second circular shoulder formed in the ring opposing the first circular shoulder and defining an aperture having a diameter that is smaller than the diameter of the circular peripheral edge of the disk, the second circular shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk.

12. The conditioning tool in accordance with claim 11, wherein the ring further comprises a first ring portion removably mounted to a second ring portion and configured to receive the disk.

13. The conditioning tool in accordance with claim 12, further comprising a key inserted into notches formed in the disk and the ring for preventing relative movement of the disk and the base.

14. An improved conditioning tool for restoring a used CMP polishing pad to an operable condition including a disk with a circular peripheral edge and a first substantially planar surface to which a first abrasive is attached and a drive mount for drivingly linking to a rotatably driven machine, the improvement comprising:

(a) the disk having a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces;

(b) a base on which the drive mount is formed, the base having a circular shoulder extending from a base surface substantially opposite the drive mount, a base shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk;

(c) a ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk; and

(d) at least one fastener mounting the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

15. The conditioning tool in accordance with claim 14, wherein said at least one fastener mounts the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder.

16. The conditioning tool in accordance with claim 15, further comprising a key inserted into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

17. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(a) a disk having a circular peripheral edge, a first substantially planar surface to which a first abrasive is attached and a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces, the circular peripheral edge including a first surface and a second surface;

(b) a base for drivingly linking to a rotatably driven machine, the base having a circular shoulder extending from a base surface, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving the first surface of the peripheral edge of the disk;

(c) a ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving the second surface of the peripheral edge of the disk; and

18. The conditioning tool in accordance with claim 17, wherein said at least one fastener mounts the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder.

19. The conditioning tool in accordance with claim 18, further comprising a key inserted into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

20. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(c) means for mounting the substrate to the base with the second abrasive spaced from the base surface to form a gap between the base surface and the second abrasive, and the first abrasive faces away from the base.

21. The conditioning tool in accordance with claim 20, wherein the substrate is a disk with a circular peripheral edge.

22. A method of restoring a used CMP polishing pad to an operable condition, the method comprising:

(b) drivingly linking a base to a rotatably driven machine, the base having a circular shoulder extending from a base surface, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk;

(a) disposing a circular peripheral edge of a disk against the base's shoulder, the disk having a first substantially planar surface to which a first abrasive is attached and a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces; and

(c) mounting a ring to the base, the ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk;

(d) clamping the disk between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

23. The method in accordance with claim 22, further comprising inserting a key into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

24. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(a) a disk having a circular peripheral edge, a first substantially planar surface to which a first abrasive is attached and a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces, the circular peripheral edge including a first surface that faces toward a second surface;

(d) at least one fastener mounting the ring to the base with the disk held between the ring and the base, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

25. A holder for a conditioning tool for restoring a used CMP polishing pad to an operable condition, the holder comprising:

(a) a base for drivingly linking to a rotatably driven machine, the base having a circular shoulder extending from a base surface configured to receive a disk having

(i) a circular peripheral edge including a first surface and a second surface;

(ii) a first substantially planar surface to which a first abrasive is attached; and

(iii) a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk for receiving the first surface of the peripheral edge of the disk;

(b) a ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk for receiving the second surface of the peripheral edge of the disk; and

(c) at least one fastener for mounting the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.