US20080014845A1

US20080014845A1 - Conditioning disk having uniform structures

Info

Publication number: US20080014845A1
Application number: US11/775,533
Authority: US
Inventors: Alpay Yilmaz; Omer Ozgun; Gerald Alonzo; Lakshmanan Karuppiah; Shou-sung Chang; Antoine P. Manens; Clinton Sakata
Original assignee: Individual
Current assignee: Applied Materials Inc
Priority date: 2006-07-11
Filing date: 2007-07-10
Publication date: 2008-01-17
Also published as: TW200821092A; WO2008008822A3; WO2008008822A2

Abstract

A method and apparatus for conditioning a conductive polishing material is described. In one embodiment, the pad dresser comprises a backing plate adapted to coupled to a conditioning head assembly, the backing plate comprising a rigid disk having a first side and an opposing second side, the second side having a perpendicular orientation to a centerline of the backing plate, and an annular member having a base portion adhered to the second side of the backing plate, wherein the annular member defines a conditioning surface opposite the second side that is radially sloped relative to a plane of the second side.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/807,066 (Attorney Docket No. 11271L), filed Jul. 11, 2006, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
Embodiments of the present invention generally relate to an apparatus and method for conditioning a polishing surface in an electrochemical mechanical processing system.
2. Description of the Related Art
Electrochemical mechanical processing (ECMP) is one process commonly used in the manufacture of high-density integrated circuits. ECMP is utilized to remove conductive material from a substrate surface by electrochemical dissolution while concurrently polishing the substrate with reduced mechanical abrasion as compared to conventional chemical mechanical processing (CMP). The electrochemical dissolution is performed by applying a bias between an electrode and the substrate surface to remove conductive materials from the substrate surface into a surrounding electrolyte. ECMP processes may be utilized to deposit material on the substrate by reversing the polarity of the bias.
In order to achieve desirable polishing results, the polishing surface of the polishing pad must be conditioned periodically to remove any accumulated polishing by-products on the pad surface and/or to refresh the surface of the pad due to wear of the pad material. Typically, a conditioning disk made of a diamond material is utilized to condition the polishing surface of the pad. The conditioning disk is coupled to a conditioning head that is movable over the polishing surface of the polishing pad. The conditioning head is lowered into contact with a rotating polishing surface and rotated relative to the polishing surface. The conditioning head is generally swept across the rotating polishing surface to allow the conditioning disk to condition the polishing surface of the polishing pad.
Some conditioning disks utilized in CMP systems include discrete diamond particles that are embedded into or adhered to a conditioning disk as a grit or coating. The diamond particles used on the surface are typically sized on the order of a few millimeters to a few microns, and may be chosen by diamond type to have similar shapes or combinations of shapes. These diamond particles are then attached to the disk in a controlled manner that produces an irregular, rough conditioning surface that is used to work or texturize portions of the CMP pad during the conditioning process. In another type of conventional conditioning disk, diamond particles may be deposited on a substrate by deposition processes, such as by chemical vapor deposition and laser deposition. These conventional conditioning disks are typically configured to provide a high cut rate suitable for conditioning the hard dielectric surfaces of CMP polishing pads.
Conversely, the polishing surface of ECMP polishing pads is softer and more delicate than the dielectric polishing pads used in CMP processes. For example, ECMP processing pads may have a conductive surface or include conductive elements or regions disposed on the polishing surface selected to prevent scratching or damaging soft materials being polished, such as copper materials. The conductive regions may be formed, for example, by conductive particles, such as tin and/or nickel, disposed in a polymer binder. Thus, conventional CMP conditioning disks and conditioning regimes are generally too aggressive for conditioning softer and more delicate ECMP polishing pads, leading to damage of the ECMP polishing pad surface and premature replacement of the polishing pad. For example, aggressive conditioning may lead to alteration of the resistance of the conductive regions, leading to process variability and reduced process control. Aggressive conditioning processes may also leave portions of the conductive particles in a rough condition, leading to scratches or other damage of the substrate being processed. Simply slowing the conditioning cut rate to produce an acceptable roughness in the polishing surface of the ECMP pad is not an acceptable approach since the required increase in conditioning time causes an unacceptable decrease in throughput.
Thus, conditioning the polishing surface of ECMP polishing pads to avoid gouging or otherwise damaging the polishing material presents a significant technical hurdle that must be overcome in order to make ECMP systems production-worthy. Once the polishing material is damaged, the polishing material must be discarded (i.e., not used for polishing) to prevent damaging the substrate being processed, thereby reducing the number of substrates that may be polished per unit quantity of polishing material and resulting in decreased system throughput and increased costs.
Therefore, there is a need for an improved conditioning element and conditioning method for conditioning the polishing surface of ECMP polishing pads.

SUMMARY OF THE INVENTION

Embodiments of a pad dresser configured to condition a polishing surface of an electrochemical mechanical polishing pad are described herein. In one embodiment, a pad dresser for conditioning a polishing pad having a conductive polishing surface is described. The pad dresser includes a backing plate adapted to couple to a conditioning head assembly, the backing plate comprising a rigid disk having a first side and an opposing second side, the second side having a perpendicular orientation to a centerline of the backing plate, and an annular member having a base portion adhered to the second side of the backing plate, wherein the annular member defines a conditioning surface opposite the second side that is radially sloped relative to a plane of the second side.
In another embodiment, a pad dresser for conditioning a polishing pad having a conductive polishing surface is described. The pad dresser includes a backing plate adapted to couple to a conditioning head assembly, the backing plate comprising a rigid disk having a first side and an opposing second side, the second side having a perpendicular orientation to a centerline of the backing plate, and an annular member having a base portion adhered to the second side of the backing plate, the annular member having a thicker cross-section at the center relative to a perimeter, and a conditioning surface disposed on the annular member opposite the base portion, wherein the conditioning surface includes a plurality of pyramidal structures disposed thereon.
In another embodiment, a pad dresser for conditioning a polishing pad having a conductive polishing surface is described. The pad dresser includes a backing plate adapted to couple to a conditioning head assembly, the backing plate comprising a rigid disk having a first side and an opposing second side, the second side having a perpendicular orientation to a centerline of the backing plate, an annular member having a base portion adhered concentrically to the second side of the backing plate, and a conditioning surface disposed on the annular member opposite the base portion comprising a plurality of adjacent pyramidal structures, wherein the conditioning surface includes a radial slope relative to a plane of the second side of the backing plate.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG. 1 is a top view of one embodiment of a portion of a processing system having one embodiment of a conditioning device.

FIG. 2 is a sectional view of the conditioning device of FIG. 1 having one embodiment of a pad dresser.

FIG. 3A is a partial exploded cross-sectional view of one embodiment of a pad dresser adapted and a conditioning head.

FIG. 3B is a bottom view of one embodiment of the pad dresser of FIG. 3A.

FIG. 3C shows a detail view of the surface of one embodiment of the conditioning surface shown in FIG. 3B.

FIGS. 4A-4D are partial cross-sectional views of alternative embodiments of a conditioning surface disposed on an annular body.

FIG. 4E is a detail cross-sectional view of a portion of one embodiment of a conditioning surface.

To facilitate understanding, identical reference numerals have been used, wherever possible, to designate identical elements that are common to the figures. It is also contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

DETAILED DESCRIPTION

Embodiments described herein relate to a conditioning disk for conditioning, which includes scoring and/or dressing, a polishing surface of a polishing pad used in an electrochemical mechanical polishing (ECMP) process. Specifically, the conditioning disk is suitable for conditioning processing pads having delicate conductive surfaces that are more typically used in ECMP systems. The inventive pad dresser comprises an annular body disposed on a backing plate. The backing plate is adapted to be coupled to a conditioning head assembly that is used to urge the pad dresser against the polishing surface of the polishing pad. The annular body comprises a polycrystalline diamond covering or coating that is adapted to refresh, score, or condition the polishing surface when in contact with the polishing surface. In some embodiments, the polycrystalline diamond covering is machined to include a plurality of substantially identical structures which condition the polishing surface of the polishing pad. The size, pitch, and height of the plurality of structures are controlled with tight tolerances to enhance the cut rate without adversely increasing surface roughness of the polishing surface, and to prevent clogging or accumulation of polishing by-products, such as metal particles and/or portions of the polishing surface that may be spent and/or torn away from the polishing surface.
FIG. 1 is a top view of one embodiment of a portion of a processing system 100 having one embodiment of a pad dresser 110 disposed on a conditioning device 115. In one embodiment, the system 100 is configured to planarize or polish semiconductor substrates and generally includes a polishing module 108, which includes one or more polishing stations 120A-120C disposed therein. Each polishing station 120A-120C includes a platen 130 that supports a polishing material 125. During processing, a substrate is urged against the polishing material 125 by a substrate carrier head 124 and the platen 130 rotates to provide at least a portion of relative polishing motion between the substrate and the polishing material 125. Processing systems that may be adapted to benefit from embodiments described herein include the REFLEXION LK ECMP™ polishing system available from Applied Materials, Inc., located in Santa Clara, Calif., although other polishing systems may be utilized.
The conditioning device 115 is disposed proximate each polishing station 120A-120C and is adapted to condition the polishing material 125 disposed on each platen 130. Each conditioning device 115 is adapted to move between a position clear of the polishing material 125 and platen 130 as shown in FIG. 1, and a conditioning position over the polishing material 125 as shown on polishing stations 120B and 120C. In the conditioning position, the conditioning device 115 selectively engages the polishing material 125 to work the surface of the polishing material 125 to a state that produces desirable polishing results. The conditioning device 115 may sweep and/or rotate relative to the polishing material 125, which may additionally rotate on the platen 130 during conditioning. Operation of the conditioning process may be controlled by a controller in response to a preprogrammed process recipe, manual input by an operator of the equipment, and the like. Alternatively, or in combination, a stand-alone conditioning apparatus (not shown) located remote from the system 100 may be utilized to condition the polishing material 125.
The polishing material 125 includes a polishing surface that is at least partially conductive. Examples of polishing material 125 may include a combination of dielectric and conductive materials. In one embodiment, the polishing material 125 may include dielectric or conductive materials having conductive elements disposed therein. The conductive elements may be flakes, particles, and the like that are disposed in a dielectric or conductive material, such as a polymer material. Examples of conductive materials used as conductive elements and/or the conductive material are copper, carbon based materials, gold, platinum, silver, tin, zinc, nickel, cobalt, and combinations thereof, among other conductive materials that are resistant to polishing chemistry. Carbon-based material includes carbon black, graphite, and carbon particles. Examples of conductive carbon-based materials include carbon powder, carbon fibers, carbon nanotubes, carbon nanofoam, carbon aerogels, graphite, and combinations thereof. In one embodiment, a conductive polishing material may include conductive foils, polymers polymer materials with conductive materials disposed therein, conductive meshes, conductive flakes, conductive fibers, or a fabric of interwoven conductive fibers. The conductive materials, fibers, or fabric may be disposed in a polymeric material.
FIG. 2 is a sectional view of the conditioning device 115 of FIG. 1 showing one embodiment of a pad dresser 110. The pad dresser 110 is disposed above a polishing material 125. The conditioning device 115 generally includes a conditioning head assembly 202 coupled to a support member 204 by an arm 206. The support member 204 is disposed through a base of the polishing module 108. Bearings are provided between the base and the support member 204 to facilitate rotation of the support member 204. An actuator 210 is coupled between the base and the support member 204 to control the rotational orientation of the support member 204. The actuator 210 allows the arm 206 extending from the support member 204 to be rotated about the support member 204, thus laterally positioning the conditioning head assembly 202 relative to the polishing station 126A. Elevation of the conditioning device 115 and/or the conditioning head 250 is generally controlled by pressurizing or venting an expandable cavity 290 partially bounded by a diaphragm disposed in conditioning head assembly 202.
The pad dresser 110 is coupled to the conditioning head assembly 202 and may be selectively pressed against the polishing material 125 while rotating to condition the polishing material 125. The pad dresser 110 includes a backing plate and a conditioning surface. The backing plate and/or the conditioning surface are typically round, disk-shaped, or annular to facilitate rotation of the pad dresser 110 and enhance conditioning of the polishing material 125 and/or control of the conditioning process.
In this embodiment, the polishing material 125 comprises a polishing pad having a first conductive layer 270 and a second conductive layer 272 separated by an insulative layer 274. The first conductive layer 270 functions as an electrode and includes a polishing surface 276 that is at least partially conductive as described above, and is adapted to contact a substrate during a polishing process. A conductive carrier 278 may be disposed between the first conductive layer 270 and the insulative layer 274 to provide additional support for the first conductive layer 270. The conductive carrier 278 may be a mesh, cloth, fabric, and the like as described above, and may be coated with a conductive material. An example of a conductive carrier is a mesh or fabric made of nylon that is coated with a conductive material, such as gold. A terminal (not shown) coupled to a power supply (not shown) may be attached to one or both of the conductive carrier 278 and the first conductive layer 270 to provide a voltage to the first conductive layer 270. The second conductive layer 272 functions as a counterelectrode to the first conductive layer 270 and may include a terminal (not shown) coupled to a different pole of the power supply.
The first conductive layer 270 may be a polymer material that includes conductive elements 280 embedded therein as described above. During polishing, a substrate (not shown) is urged against the polishing material 125, the first conductive layer 270 is electrically coupled to conductive material deposited on the face of the substrate. The first conductive layer 270 and/or the conductive material on the substrate are in electrical communication with the second conductive layer 272 through an electrolyte provided to the surface of the polishing material 125. In one embodiment, the electrolyte flows through openings 282 formed through a portion of the polishing material at least to an upper surface of the second conductive layer 272. As one or both of the platen 130 and substrate are rotated, conductive material is removed from the face of the substrate by electrochemical and mechanical forces.
Before, during, or after the polishing process, the polishing surface 276 may require conditioning of the pad polishing surface in order to maintain predefined processing results. Conditioning may create, reform, and/or clear grooves and/or asperities in the polishing surface 276. In another application, conditioning of the polishing surface 276 refreshes the polishing surface 276. Refreshing may include at least one of exposing new or unused material on the polishing surface 276, removing polishing by-products, removing spent or torn portions of the polishing surface 276, and/or removal or minimization of oxides disposed in or on the polishing surface 276. The conditioning of the polishing surface 276 may be performed prior to polishing with a new polishing pad, during the polishing process to maintain and/or enhance surface roughness and removal rate of the polishing surface 276, or post-processing to prepare the polishing surface 276 for a new substrate to be polished.
FIGS. 3A and 3B respectively show an exploded cross-sectional view and a bottom view of one embodiment of the pad dresser 110. In one embodiment, the pad dresser 110 includes an annular member 310 disposed on a backing disk or plate 305 coupled to a face 316 of the conditioning head 250. The backing plate 305 couples to a conditioning head assembly (FIG. 2). The backing plate 305 includes a first surface 317 that couples to the face 316 of the conditioning head 250. The backing plate 305 also includes a second surface 318 opposite the first surface 317. At least one of the first surface 317 and second surface 318 is disposed in a plane orthogonal to a center line 330 of the backing plate 305. In the embodiment depicted in FIGS. 3A and 3B, the annular member 310 couples concentrically to the backing plate 305 and the backing plate 305 couples concentrically to the conditioning head 250. The annular member 310 comprises a lesser dimension, such as a diameter, than the backing plate 305, and portions of the second surface 318 of the backing plate 305 are exposed, such as an outer portion 306 and an inner portion 304. In one embodiment, the dimension of the backing plate 305 extends beyond the dimension of the annular member 310 on an outer portion thereof. Although the annular member 310 is described and depicted as annular or ring-like, the annular member 310 may alternatively be a solid disk or plate void of any inner diameter.
In one embodiment, the backing plate 305 comprises a rigid material, such as a ceramic or metal, for example stainless steel, aluminum, among other metals. The first surface 317 of the backing plate 305 is adapted to abut with the face 317 of the conditioning head 250. Openings 319 are formed in the backing plate 305 to facilitate coupling of the backing plate 305 to the conditioning head 250. The openings 319 may be adapted to receive alignment pins or fasteners (not shown) that engage with mating holes 322 and/or 324. In one embodiment, at least one of the mating holes 322 and 324 include female threads. For example, the backing plate 305 may have one or more openings 319 formed in the outer portion 306 to facilitate coupling to the conditioning head 250 via fasteners, such as screws, bolts, pins, or the like. In the embodiment depicted in FIGS. 3A-3B, four threaded holes 324 are formed along an outer diameter of the conditioning head 250. In addition, one or more apertures (not shown) may be formed in the backing plate 305 to mate with a feature, such as a locating pin (not shown) that extends from the conditioning head 250.
The annular member 310 generally comprises an annular body 320 and a conditioning surface 315 formed thereon. In an alternative embodiment (not shown), the annular body 320 may be a solid flat cylindrical member having the conditioning surface 315 disposed thereon. The annular body 320 comprises a carbide material, such as tungsten carbide, that is coupled to the second surface 318 of the backing plate 305. The annular body 320 may be adhered to the backing plate 305 by an adhesive 328, such as an epoxy material or other suitable adhesive material. In one embodiment, the thickness of the annular member 310 is about 2.0 mm to about 3.5 mm, and the thickness of the conditioning surface 315 is greater than or equal to about 0.3 mm. In one application, the ratio of the outside diameter of the annular member 310 to the inside diameter of the annular member 310 is about 1.84:1. In one embodiment, the backing plate 305 includes an annular channel 326 formed therein, and the annular body 320 is configured to be received by the annular channel 326.
In one embodiment, the annular member 310 is sloped or convex relative to the plane of the second surface 318 of the backing plate 305. For example, the annular member 310 may be center-thick and slope or curve radially outward (and upward as shown in FIG. 3A) to a lesser cross-sectional dimension on a perimeter thereof. In one application, the annular body 320 may be center-thick or sloped such that the conditioning surface 315 formed thereon is sloped or convex relative to the plane of the second surface 318 of the backing plate 305. In this embodiment, the conditioning surface 315 formed thereon may comprise a substantially equal cross-sectional thickness across the annular body 320. In another application (not shown), the annular body 320 may comprise a substantially equal thickness in the center and a perimeter thereof, and the conditioning surface 315 formed thereon may be machined to be center-thick, such that the conditioning surface 315 is sloped or convex relative to the plane of the second surface 318 of the backing plate 305.
In one embodiment, the annular member 310 includes a dimension 355 that includes a delta from the center portion of the annular member 310 to a perimeter thereof. The dimension 355 may be a linear delta or curved delta of less than or equal to about 50 μm, such as less than or equal to about 40 μm. Additionally, the perimeter of the annular body 320 may be relieved to minimize or avoid damaging the polishing surface of a polishing pad (not shown) through contact during conditioning. As an example, the outer diameter and/or inside diameter of the annular body may be beveled, rounded, chamfered, and the like to relieve edges at the perimeter of the annular body 320. The conditioning surface 315 disposed thereon may follow any relieved portions of the annular body 320 to prevent or minimize damage to the polishing surface of the polishing pad.
The conditioning surface 315 comprises a polycrystalline diamond coating or layer having structures 350 formed therein and extending therefrom. In one embodiment, the conditioning surface 315 is made of polycrystalline diamond coating that is formed by fusing fine diamond powder at high temperatures and pressures to form a monolithic diamond coating. In one embodiment, micron diamond powder having micron sized grains is sintered to form the conditioning surface 315. Temperatures of greater than 1300° C. and pressures of greater than 5 gigapascals are generally used to sinter the coating. In one embodiment, molten cobalt is used to aid the fusing process, which results in trace amounts of conductive cobalt being left in the polycrystalline diamond surface. In this embodiment, the plurality of structures 350 may be formed by wire electromotive discharge (WEMD) machining to produce many different sizes, shapes, and patterns of structures 350.
The backing plate 305 may be any shape, such as circular, annular, or disk-shaped. In one embodiment, the backing plate 305 has a diameter between about 100 mm and about 110 mm, such as about 108 mm. The backing plate 305 is generally stiff or rigid enough to minimize flexing under processing conditions. The rigidity of the backing plate 305 may be obtained by material selection and/or the thickness of the backing plate 305. For example, the backing plate 305 may be made of a rigid material and have a thickness of between about 6 mm and about 7 mm.
FIG. 3C shows a detail view of one embodiment of the conditioning surface 315 shown in FIG. 3B. The conditioning surface 315 comprises a plurality of structures 350 that are configured to have highly uniform geometry and spacing across the conditioning surface 315. For example, the structures 350 are uniformly spaced across the conditioning surface 315. Each structure 350 includes a base 352 and a tip 354. Each structure 350 may have a pyramidal, conical, polygonal, or other suitable shape. For example, the structures 350 may be polygonal structures, such as three or four-sided rectangles, or a combination thereof. The structures 350 may be disposed across the conditioning surface 315 in a grid-like or X/Y pattern as shown, or the structures 350 may be grouped or formed in another uniform pattern, such as a polar array, across the conditioning surface 315. In other embodiments (not shown), spacing of the structures 350 may be configured as a non-uniform pattern.
In one embodiment, each structure 350 comprises a pyramidal shape having a four sided base 352, although the base may be any polygonal shape having three sides or more than four sides. In this embodiment, the base 352 of each structure 350 has a substantially rectangular shape with a width between about 0.1 mm and about 0.2 mm, such as between about 0.15 and about 0.17 mm, or about 0.16 mm. Shapes of structures 350 other than pyramids may be used, such cubes, three-dimensional rectangles, cones, frustrums, cylinders, or combinations thereof. The structures 350 may have a spacing or pitch, measured between the tips 354, between about 450 microns (μm) and about 550 μm, such as between about 475 μm and about 525 μm. In one application, each base 352 is adjacent other bases 352 such that where one structure 350 ends, another structure 350 begins.
In one embodiment, the structures 350 are configured as cutting edges adapted to form grooves or channels in the polishing surface 276 (FIG. 2) of a polishing pad during a conditioning process. The uniformity of structure height and spacing permits grooving in the polishing surface to a substantially uniform depth, which results in enhanced polishing results due to the substantially uniform asperities formed in the polishing surface. Additionally, the shaping of the structures 350 enhances clearing of polishing by-products to enable a more uniform grooving depth and conditioning regime on the polishing surface.
The backing plate 305 may be any shape, such as circular, annular, or disk-shaped. In one embodiment, the backing plate 305 has a diameter between about 100 mm and about 110 mm, such as about 108 mm. The backing plate 305 is generally stiff or rigid enough to minimize flexing under processing conditions. The rigidity of the backing plate 305 may be obtained by material selection and/or the thickness of the backing plate 305. For example, the backing plate 305 may be made of a rigid material and have a thickness of between about 6 mm and about 7 mm.
FIG. 4A is a partial cross-sectional view of one embodiment of a conditioning surface 416 ₁disposed on an annular body 320. The conditioning surface 416 ₁is similar to the embodiments of the conditioning surface 315 described above. The conditioning surface 416 ₁comprises a plurality of structures 350 extending from a trough or bottom 400, which indicates an interface between adjacent structures 350. In one embodiment, the bottoms 400 are in a grid-like or X/Y pattern across the conditioning surface 315 as shown in FIGS. 3B and 3C, and where one structure 350 ends at the bottom 400, another structure 350 begins in a substantially equidistant and repeating pattern.
In this embodiment, the structures 350 are of a substantially equal height “H” above the bottom 400 and are distributed in a substantially equidistant pattern across the conditioning surface 315. In this embodiment, each of the structures are of a substantially equal height, such as within about ±30 μm. For example, the height H of each structure 350 may be about 170 μm with a deviation of ±30 μm. In one embodiment, the deviation in height between any two adjacent tips 354 is less than or equal to about 30 μm, such as less than or equal to about 25 μm.
FIG. 4B is a partial cross-sectional view of another embodiment of a conditioning surface 416 ₂disposed on an annular body 320. The conditioning surface 416 ₁is similar to the embodiments of the conditioning surface 315 described above. The conditioning surface 416 ₂includes structures 350 having at least two different heights. In this embodiment, a portion of the plurality of structures 350 may comprise a first height similar to the height of the structures 350 as described above in reference to FIG. 4A, and the remainder of the plurality of structures 350 include a second height of about one-half of the first height.
FIGS. 4C and 4D are partial cross-sectional views of other embodiments structures 350 formed in or on a conditioning surface 416 ₃and 416 ₄. In the embodiment of FIG. 4C, structures 350 are formed on the conditioning surface 416 ₃and comprise similar shapes as structures 350 described above. In this embodiment, the structures 350 comprise a first height, a second height, and a third height in a repeating pattern. The first height is greater than the second height, and the second height is greater than the third height. Each of the first heights are substantially equal to each other, as respectively are the second and third heights. Thus, a uniform pattern in the conditioning surface 416 ₃is formed. In the embodiment of FIG. 4D, a plurality of structures 350 are shown as having progressive increasing (or decreasing) heights to create a defined across the tips 354 of the conditioning surface 416 ₄. Each of the heights (13 are shown in this cross-sectional view) may be some fraction of the highest structure 350, and each change in height between adjacent tips 354 may be substantially equal. The progressive heights may begin on an outer diameter of the conditioning surface 416 ₄and slope downward and inward toward in inner diameter of the conditioning surface 416 ₄, or vice versa. In this embodiment, the cross-sectional thickness of the conditioning surface 416 ₄may be substantially equal across the width of the annular body 320. Alternatively, the cross-sectional thickness of the conditioning surface 416 ₄may be lesser at the inner diameter of the annular body 320, or vice versa.
FIG. 4E is a detail cross-sectional view of a portion of another embodiment of a conditioning surface 315. Each structure 350 extends from a trough or bottom 400 to a tip 354. Each adjacent sidewall of each structure includes a first angle 410 and an adjacent angle 420 as measured from reference line 425. In one embodiment, reference line 425 is perpendicular to an upper surface of the annular body 320. In one application, the first angle 410 and the adjacent angle 420 is substantially equal. For example, the first angle 410 and the adjacent angle 420 is about 42 degrees to about 46 degrees, such as about 44 degrees. In one embodiment, the first angle 410 and the adjacent angle 420 defining the bottom 400 is about 86 degrees to about 94 degrees, such as about 88 degrees.
While not shown, at least a portion of the plurality of structures 350 may be flattened at the tip 354. Further, a portion of the flattened tips 354 may be grooved, rounded, or include a sharp transition from the flat tip to the sidewall of the structure 350. Additionally, spaces between the structures 350 may be formed in the conditioning surface 315 by spacing the bases 352 of the structures 350 leaving a flat and/or groove therebetween.
A polycrystalline diamond surface is very durable to resist crystal breakage and/or crystal dislodgment during conditioning. Polycrystalline diamond layers or coatings comprising the conditioning surface 315 as described herein can be machined to produce any configuration and combination of structure and/or tip size, shape, and spacing. The heights of the structures and/or tips may be controlled to form uniform or non-uniform sizes. Structures may be organized with uniform spacing according to a geometric pattern, or spacing may be controllably non-uniform. The uniformity and control of structure shape and height may be selected to provide more structures contacting the polishing surface during conditioning. Additionally, individual structures 350 are subjected to less mechanical stress, which extends the life of the pad dresser 110. The frequency, pitch, height, and shape of the structures 350 are also selected to minimize or eliminate accumulation of by-products, for example conductive elements and other objects from the polishing surface 125. This results in a highly repeatable scoring or conditioning pattern on the polishing pad. Thus, conditioning of the polishing pad is more uniform, and load distribution is spread more evenly among the structures 350, which also extends the service life of the pad dresser 110.
Likewise, the conditioning of the delicate polishing surface 125 of the polishing pad is less aggressive and creates substantially uniform asperities in the polishing surface 125. This results in longer pad lifetime. Experimental results have shown that using a polycrystalline diamond coating as the conditioning surface 315 has doubled the usable life of the polishing material of the polishing pad. The spacing and/or size of the structures produce uniform cuts and grooving of the polishing material and has been shown to be substantially uniform, thus producing substantially uniform asperities in the polishing material. This has resulted in an increase in polishing pad life from about 1500 wafers to about 3000 wafers, which results in lower cost of ownership and higher throughput as pad replacement is minimized. Further, the uniform conditioning of the polishing surface provides an acceptable surface roughness of the polishing surface in faster conditioning periods, which results in enhanced throughput of the system.
The use of a polycrystalline diamond coating as the conditioning surface 315 also enables the pad dresser 110 to be resurfaced. The polycrystalline diamond coating may be re-worked to reproduce the original geometry of the structures 350 many times before the polycrystalline diamond coating is worn away. This results in lower cost of ownership as used conditioning elements may be refurbished instead of replaced.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. An apparatus for conditioning a polishing pad having a conductive polishing surface, comprising:

a backing plate adapted to couple to a conditioning head assembly, the backing plate comprising a rigid disk having a first side and an opposing second side, the second side having a perpendicular orientation to a centerline of the backing plate; and

an annular member having a base portion adhered to the second side of the backing plate, wherein the annular member defines a conditioning surface opposite the second side that is radially sloped relative to a plane of the second side.

2. The apparatus of claim 1, wherein the base portion is made of a carbide material.

3. The apparatus of claim 1, wherein the conditioning surface comprises a polycrystalline diamond coating disposed on the base portion.

4. The apparatus of claim 1, wherein the conditioning surface comprises a plurality of pyramidal structures.

5. The apparatus of claim 4, wherein each of the pyramidal structures include at least one of a three-sided base or a four-sided base.

6. The apparatus of claim 4, wherein each of the pyramidal structures include a four-sided base and each four-sided base is in contact with adjacent four-sided bases.

7. The apparatus of claim 4, wherein adjacent pyramidal structures are in contact with each other.

8. The apparatus of claim 4, wherein the pyramidal structures are spaced in an array.

9. The apparatus of claim 8, wherein the array comprises an X/Y grid.

10. The apparatus of claim 8, wherein each of the pyramidal structures include a base and each base is in a spaced apart relation.

11. The apparatus of claim 8, wherein each of the pyramidal structures include a base and each base is in contact with at least one adjacent base.

12. The apparatus of claim 1, wherein the annular member is thicker in a center region relative to a perimeter thereof.

13. The apparatus of claim 4, wherein a first portion of the plurality of pyramidal structures comprise a first height, and a second portion of the plurality of pyramidal structures include a second height that is less than the first height.

14. The apparatus of claim 1, wherein the backing plate has an annular channel having the annular member adhered thereto.

15. An apparatus for conditioning a polishing pad having a conductive polishing surface, comprising:

a backing plate adapted to couple to a conditioning head assembly, the backing plate comprising a rigid disk having a first side and an opposing second side, the second side having a perpendicular orientation to a centerline of the backing plate;

an annular member having a base portion adhered to the second side of the backing plate, the annular member having a thicker cross-section at the center relative to a perimeter; and

a conditioning surface disposed on the annular member opposite the base portion, wherein the conditioning surface includes a plurality of pyramidal structures disposed thereon.

16. The apparatus of claim 15, wherein each of the pyramidal structures include a four-sided base and each four-sided base is in contact with adjacent four-sided bases.

17. The apparatus of claim 15, wherein the conditioning surface comprises a polycrystalline diamond coating disposed on the base portion.

18. The apparatus of claim 15, wherein the base portion is made of a carbide material.

19. The apparatus of claim 15, wherein adjacent pyramidal structures are in contact with each other.

20. The apparatus of claim 15, wherein the backing plate comprises stainless steel.

21. The apparatus of claim 15, wherein the backing plate has an annular channel having the annular member adhered thereto.

22. The apparatus of claim 15, wherein a first portion of the plurality of pyramidal structures comprise a first height, and a second portion of the plurality of pyramidal structures include a second height that is less than the first height.

23. An apparatus for conditioning a polishing pad having a conductive polishing surface, comprising:

an annular member having a base portion adhered concentrically to the second side of the backing plate; and

a conditioning surface disposed on the annular member opposite the base portion comprising a plurality of adjacent pyramidal structures, wherein the conditioning surface includes a radial slope relative to a plane of the second side of the backing plate.

24. The apparatus of claim 23, wherein the conditioning surface comprises a polycrystalline diamond coating disposed on the base portion.

25. The apparatus of claim 23, wherein the base portion is made of a carbide material.

26. The apparatus of claim 23, wherein at least a portion of the plurality of pyramidal structures are in contact with each other.

27. The apparatus of claim 23, wherein the backing plate has an annular channel having the annular member adhered thereto.

28. The apparatus of claim 23, wherein a first portion of the plurality of pyramidal structures comprise a first height, and a second portion of the plurality of pyramidal structures include a second height that is less than the first height.