Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
  • B24B37/11—Lapping tools
  • B24B37/20—Lapping pads for working plane surfaces
  • B24B37/24—Lapping pads for working plane surfaces characterised by the composition or properties of the pad materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
  • B24B37/11—Lapping tools
  • B24B37/20—Lapping pads for working plane surfaces
  • B24B37/26—Lapping pads for working plane surfaces characterised by the shape of the lapping pad surface, e.g. grooved
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
  • B24B37/11—Lapping tools
  • B24B37/20—Lapping pads for working plane surfaces
  • B24B37/205—Lapping pads for working plane surfaces provided with a window for inspecting the surface of the work being lapped
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
  • B24B37/11—Lapping tools
  • B24B37/20—Lapping pads for working plane surfaces
  • B24B37/22—Lapping pads for working plane surfaces characterised by a multi-layered structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D13/00—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor
  • B24D13/14—Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor acting by the front face
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for

Definitions

• the present disclosure relates to polishing pads with floating polishing elements, and to methods of making and using such polishing pads in a polishing process, for example, in a chemical mechanical planarization process
• CMP chemical mechanical planarization
• a substrate such as a wafer is pressed against and relatively moved with respect to a polishing pad in the presence of a working liquid that is typically a slurry of abrasive particles in water and/or an etching chemistry
• a working liquid typically a slurry of abrasive particles in water and/or an etching chemistry
• abrasive polishing pads for use with abrasive slurries have been disclosed, for example, U S Pat Nos 5,257,478, 5,921,855, 6,126,532; 6,899,598 B2, and 7,267,610
• Fixed abrasive polishing pads are also known, as exemplified by U S Pat No 6,908,366 B2, in which the abrasive particles are generally fixed to the surface of the pad, often in the form of precisely shaped abrasive composites extending from the pad surface
• polishing pads Although a wide variety of polishing pads are known and used, the art continues to seek new and improved polishing pads for CMP, particularly in CMP processes where larger die diameters are being used, or where higher levels of wafer surface flatness and polishing uniformity are required SUMMARY
• the present disclosure describes a polishing pad comprising a plurality of polishing elements, each of the polishing elements bonded to a support layer so as to restrict lateral movement of the polishing elements with respect to one or more of the other polishing elements, but remaining moveable in an axis normal to a polishing surface of the polishing elements
• the polishing elements are thermally bonded to the support layer
• at least a portion of the polishing elements comprise porous polishing elements, and in additional embodiments, at least a surface of each porous polishing element comprises a plurality of pores.
• the pores may be distributed throughout substantially the entire porous polishing element In other particular embodiments of porous polishing elements, the pores may be distributed substantially at the polishing surface of the element In certain exemplary embodiments, the pores distributed substantially at the polishing surface of the element comprise a plurality of channels having a cross-sectional shape selected from the group consisting of cylindrical, triangular, rectangular, trapezoidal, hemispherical, and combinations thereof
• the present disclosure describes a polishing pad comprising a support layer having a first major side and a second major side opposite the first major side, and a plurality of polishing elements affixed to the first major side of the support layer, wherein the polishing elements extend from the first major side of the support layer along a first direction substantially normal to the first major side
• the polishing elements are thermally bonded to the support layer
• at least a portion of the polishing elements comprise porous polishing elements, and in additional embodiments, at least a surface of each porous polishing element comprises a plurality of pores
• the pores may be distributed throughout substantially the entire porous polishing element In other particular embodiments, the pores may be distributed substantially at the polishing surface of the elements In some exemplary embodiments, the pores distributed substantially at the polishing surface of the element comprise a plurality of channels having a cross-sectional shape selected from the group consisting of cylindrical, triangular, rectangular, trapezoidal, hemispherical, and combinations thereof
• a method of making a polishing pad comprising forming a plurality of polishing elements, and bonding the polishing elements to a support layer
• bonding the polishing elements to the support layer comprises thermal bonding, actinic radiation bonding, adhesive bonding, and combinations thereof
• the method further comprises arranging the plurality of polishing elements in a pattern before bonding the polishing elements to the support layer
• arranging the plurality of polishing elements in a pattern comprises arranging the polishing elements in a template, arranging the polishing elements on the support layer, and combinations thereof
• at least a portion of the polishing elements comprise porous polishing elements
• at least a portion of the polishing elements comprise substantially non-porous polishing elements
• the method includes forming porous polishing elements by injection molding of a gas saturated polymer melt, injection molding of a reactive mixture that evolves a gas upon reaction to form a polymer, injection molding of a mixture comprising a polymer dissolved in a supercritical gas, injection molding of a mixture of incompatible polymers in a solvent, injection molding of porous thermoset particulates dispersed in a thermoplastic polymer, and combinations thereof
• the present disclosure is directed to a method of using a polishing pad as described above in a polishing process, the method comprising contacting a surface of a substrate with a polishing surface of a polishing pad comprising a plurality of polishing elements thermally bonded to a support layer, and relatively moving the polishing pad with respect to the substrate to abrade the surface of the substrate
• at least a portion of the polishing elements comprise porous polishing elements, and in certain embodiments, at least a surface of each porous polishing element comprises a plurality of pores
• a working liquid may be provided to an interface between the polishing pad surface and the substrate surface
• polishing pads having porous polishing elements have various features and characteristics that enable their use in a variety of polishing applications
• polishing pads of the present disclosure may be particularly well suited for chemical mechanical planarization (CMP) of wafers used in manufacturing integrated circuits and semiconductor devices
• CMP chemical mechanical planarization
• the polishing pad described in this disclosure may provide some or all of the following advantages
• a polishing pad according to the present disclosure may act to better retain a working liquid used in the CMP process at the interface between the polishing surface of the pad and the substrate surface being polished, thereby improving the effectiveness of the working liquid in augmenting polishing
• a polishing pad according to the present disclosure may reduce or eliminate dishing and/or edge erosion of the wafer surface during polishing
• polishing pad with porous elements may permit processing of larger diameter wafers while maintaining the required degree of surface uniformity to obtain high chip yield, processing of more wafers before conditioning of the pad surface is needed in order to maintain polishing uniformity of the wafer surfaces, or reducing process time and wear on the pad conditioner
• CMP pads with porous polishing elements may also offer the benefits and advantages of conventional CMP pads having surface textures such as grooves, but may be manufactured more reproducibly at a lower cost
• bonding of the polishing elements to the support layer may eliminate the need to use a guide plate to affix the elements to the support layer
• FIG 2 is a side view of a polishing pad having floating polishing elements bonded to a support layer and including a guide plate according to another exemplary embodiment of the disclosure
• FIG 3 A is a perspective view of a template with polishing elements arranged in a pattern useful in fabricating a polishing pad according to one exemplary embodiment of the disclosure
• FIG 3B is a top view of a template with polishing elements arranged in a pattern useful in fabricating a polishing pad according to one exemplary embodiment of the disclosure
• FIG 4 is a perspective view of a porous polishing element having a porous polishing surface according to another exemplary embodiment of the disclosure
• FIG 5 is a side view of an exemplary bonding apparatus useful in a method for bonding a multiplicity of polishing elements to a support layer according to an exemplary embodiment of the disclosure
• FIG 6 is an image showing a template useful in arranging a multiplicity of polishing elements into a pattern before bonding the polishing elements to a support layer, and the resulting support layer having a multiplicity of bonded polishing elements arranged in the pattern, according to an additional exemplary embodiment of the disclosure
• FIG 7 is an image of the resulting support layer having a multiplicity of bonded polishing elements arranged in the pattern, according to the embodiment of FIG 6
• FIG 8 is an image of a polishing pad according to yet another exemplary embodiment of the disclosure, the polishing pad comprising the multiplicity of floating polishing elements bonded to the support layer according to the embodiment of FIG 7, the support layer being affixed to a compliant underlayer
• Like reference numerals in the drawings indicate like elements
• the drawings herein are not drawn to scale, and in the drawings the components of the polishing pads are sized to emphasize selected features DETAILED DESCRIPTION
• a wafer possessing a characteristic topography is put in contact with a polishing pad and a polishing solution containing an abrasive and a polishing chemistry If the polishing pad is compliant, the phenomenon of dishing and erosion may occur due to the soft pad polishing the low areas on the wafer at the same rate as the raised areas If the polishing pad is rigid, dishing and erosion may be greatly reduced, however, although rigid polishing pads may advantageously yield good within die planarization uniformity, they may also disadvantageously yield poor within wafer uniformity, due to a rebound effect which occurs on the wafer perimeter.
• polishing pads with a multiplicity of floating polishing elements bonded to a support layer which in various embodiments combine some of the advantageous characteristics of both compliant and rigid polishing pads, while eliminating or reducing some of the disadvantageous characteristics of the respective pads
• polishing elements as "floating" polishing elements bonded to a support layer
• Applicant means that each of the polishing elements is bonded to a support layer so as to restrict lateral movement of the polishing elements with respect to one or more of the other polishing elements, but remaining moveable in an axis generally normal to a polishing surface of the polishing elements
• a polishing pad 2 comprising a plurality of polishing elements 4-4', each of the polishing elements 4-4' being bonded to a support layer 10 so as to restrict lateral movement of the polishing elements 4-4' with respect to one or more of the other polishing elements 4-4', but remaining moveable in an axis normal to a polishing surface 14 of each polishing element 4-4'
• the polishing elements 4-4' are shown affixed to a first major side of the support layer 10, for example, by direct thermal bonding to the support layer 10, or by using an adhesive
• support layer 10 is affixed to a compliant layer 16 positioned on a side opposite the plurality of polishing elements 4-4'
• an optional adhesive layer 12 is shown at an interface between compliant layer 16 and the support layer 10
• Optional adhesive layer 12 may be used to affix the second major side of the support layer 10 to the compliant layer 16
• an optional pressure sensitive adhesive layer 18, affixed to the compliant layer 16 opposite the plurality of polishing elements 4-4' may be used to temporarily (e g , removably) secure the polishing pad 2 to a polishing platen (not shown in FIG 1) of a CMP polishing apparatus (not shown in FIG 1)
• polishing composition distribution layer 8 which may also serve as a guide plate for the polishing elements 4-4', is additionally shown in FIG 1 During a polishing process, the optional polishing composition distribution layer 8 aids distribution of the working liquid and/or polishing slurry to the individual polishing elements 4-4'
• the polishing composition distribution layer 8 (guide plate) may be positioned on the first major side of the support layer 10 to facilitate arrangement of the plurality of polishing elements 4-4', such that a first major surface of the polishing composition distribution layer 8 (guide plate) is distal from the support layer 10, and a second major surface of the polishing composition distribution layer 8 (guide plate) is opposite the first major surface of the polishing composition distribution layer 8 (guide plate)
• the polishing elements 4-4' extend from the first major surface of the polishing composition distribution layer 8 (guide plate) along a first direction substantially normal to the first major side of the support layer 10 If polishing composition distribution layer 8 is also used as a guide plate, then preferably, a plurality of apertures 6 are provided
• polishing elements 4-4' are porous polishing elements 4, and some polishing elements 4-4' are substantially nonporous polishing elements 4' It will be understood, however, that in other exemplary embodiments not shown in FIG 1, all of the polishing elements 4-4' may be selected to be porous polishing elements 4, or all of the polishing elements 4-4' may be selected to be substantially nonporous polishing elements 4' In the particular embodiment illustrated by FIG 1, two porous polishing elements
• porous polishing elements 4 are shown along with one substantially nonporous polishing element 4' Furthermore, the porous polishing elements 4 are shown as including both a porous polishing surface 14 and pores 15 distributed substantially throughout the entire polishing element 4 However, it will be understood that any number of polishing elements 4-4' may be used, and that any number of polishing elements 4-4' may be selected to be porous polishing elements 4 or substantially nonporous polishing elements 4'
• the multiplicity of polishing elements 4-4' may be arranged in a pattern, for example, on a major surface of the support layer 10, or in a template or jig used to arrange the polishing elements before bonding to the support layer
• FIGs 3 A-3B illustrate one exemplary arrangement of a plurality of polishing elements 4-4' arranged in a generally circular two-dimensional array pattern 32 in a template 30
• a first major side of the support layer 10 may be contacted with and bonded to the plurality of polishing elements 4-4', for example, by direct thermal bonding to the support layer 10, or by using an adhesive, or other bonding material
• the polishing pad 2 need not comprise only substantially identical polishing elements 4
• any combination or arrangement of porous polishing elements and non-porous polishing elements may make up the plurality of porous polishing elements 4.
• porous polishing elements 4 and substantially nonporous polishing elements 4' may be used advantageously in certain embodiments to form a polishing pad having floating polishing elements 4-4' bonded to a support layer 10.
• FIG. 10 In some additional exemplary embodiments illustrated by FIG.
• a surface of a porous polishing element 4, in this case at least polishing surface 14, comprises a plurality of pores (not shown in FIG 1, but illustrated in FIG 4)
• each of the porous polishing elements 4 is also shown as having a plurality of pores 15 distributed substantially throughout the entire polishing element 4
• the pores are distributed substantially at or near only the polishing surface 14 of the porous polishing elements 4.
• polishing pads 2 having combinations or arrangements of polishing elements 4 with pores distributed substantially throughout the entire polishing element 4, polishing elements 4 with pores distributed substantially at or near only the polishing surface 14 of the polishing element 4, and polishing elements 4 with substantially no pores, are contemplated within the scope of the present disclosure, and may also be advantageously fabricated
• FIG 2 another exemplary embodiment of a polishing pad 2' is shown, the polishing pad 2' comprising a support layer 10 having a first major side and a second major side opposite the first major side, a plurality of polishing elements 4-4' bonded to the first major side of the support layer 10, and an optional guide plate 28 having a first maj or surface and a second maj or surface opposite the first maj or surface, the guide plate 28 positioned to arrange the plurality of polishing elements 4-4' on the first major side of support layer 10 with the first major surface of optional guide plate 28 distal from the support layer 10
• the polishing elements 4-4' are shown affixed to a first major side of the support layer 10, for example, by direct thermal bonding to the support layer 10, or by using an adhesive
• support layer 10 is affixed to a compliant layer 16 positioned on the second major side of the support layer 10 opposite the plurality of polishing elements 4-4' affixed to the first major side of the support layer 10
• an optional adhesive layer 12 is shown at an interface between compliant layer 16 and the support layer 10
• Optional adhesive layer 12 may be used to affix the second major side of the support layer 10 to the compliant layer 16
• an optional pressure sensitive adhesive layer 18, affixed to the compliant layer 16 opposite the plurality of polishing elements 4-4' may be used to temporarily (e g , removably) secure the polishing pad 2' to a polishing platen (not shown in FIG. 2) of a CMP polishing apparatus (not shown in FIG 2)
• An optional guide plate 28 is also shown in the exemplary embodiment of FIG 2
• the optional guide plate 28 may be entirely eliminated from the polishing pad, as illustrated by polishing pad 2 of FIG 1
• Such embodiments may advantageously be easier and less expensive to fabricate than other known polishing pads comprising a multiplicity of polishing elements
• An optional polishing composition distribution layer 8' which may also serve as a guide plate for the polishing elements 4-4', is additionally shown in FIG 2 During a polishing process, the optional polishing composition distribution layer 8' aids distribution of the working liquid and/or polishing slurry to the individual polishing elements 4-4'
• the polishing composition distribution layer 8 may be positioned on the first major side of the support layer 10 to facilitate arrangement of the plurality of polishing elements 4-4', such that a first major surface of the polishing composition distribution layer 8' is distal from the support layer 10, and a second major surface of the polishing composition distribution layer 8' is opposite the first major surface of the polishing composition distribution layer 8'
• a plurality of apertures 6 may also be provided extending through at least the optional guide plate 28 (if present) and/or the optional polishing composition distribution layer 8' (if present), as shown in FIG 2
• each polishing element 4-4' extends from the first major surface of the optional guide plate 28 along a first direction substantially normal to the first major side of support layer 10
• each polishing element 4-4' has a mounting flange, and each polishing element 4-4' is bonded to the first major side of the support layer 10 by engagement of the corresponding flange to the first major side of the support layer 10, and optionally, the second major surface of optional polishing composition distribution layer 8' Consequently, during a polishing process, the polishing elements 4-4' are free to independently undergo displacement in a direction substantially normal to the first major side of support layer 10, while still remaining bonded to the support layer 10, and optionally additionally affixed to the support layer 10 by the optional polishing composition distribution layer 8'
• each polishing element 4-4' extends into a corresponding aperture 6, and each polishing element 4-4' also passes through the corresponding aperture 6 and extends outwardly from the first major surface of the optional guide plate 28
• the plurality of apertures 6 of optional guide plate 28 and/or optional polishing composition distribution layer 8' may also serve as a template to guide the lateral arrangement of polishing elements 4-4' on the first major side of support layer 10
• optional guide plate 28 and/or optional polishing composition distribution layer 8' may be used as a template or guide to arrange the plurality of polishing elements 4-4' on the first major side of support layer 10 during the polishing pad fabrication process.
• the optional guide plate 28 may comprise an adhesive (not shown) positioned at the interface between the support layer 10 and the polishing composition distribution layer 8'
• the optional guide plate 28 may thus be used to affix the optional polishing composition distribution layer 8' to the support layer 10, thereby securely affixing the plurality of polishing elements 4-4' to the first major side of support layer 10
• other bonding methods may be used, including direct bonding of the polishing elements 4-4' to the support layer 10 using, for example, heat and pressure
• the plurality of apertures may be arranged as an array of apertures, wherein at least a portion of the apertures 6 comprise a main bore formed by optional polishing composition distribution layer 8', and an undercut region formed by optional guide plate 28, and the undercut region forms a shoulder that engages with the corresponding polishing element flange, thereby securely affixing polishing elements 4-4' to support layer 10 without requiring direct bonding of the polishing elements 4-4' to support layer 10
• the multiplicity of polishing elements 4-4' may be arranged in a pattern, for example, as a two-dimensional array of elements arranged on a major surface of the support layer 10, or in a template or jig used to arrange the polishing elements before bonding to the support layer.
• At least a surface of a porous polishing element 4 in this case at least polishing surface 14 comprises a plurality of pores (not shown in FIG. 2, but illustrated in FIG 4).
• each of the porous polishing elements 4 is also shown as having a plurality of pores 15 distributed substantially throughout the entire polishing element 4
• the pores are distributed substantially at or near only the polishing surface 14 of the porous polishing elements 4
• polishing pads 2' having combinations or arrangements of polishing elements 4 with pores distributed substantially throughout the entire polishing element 4, polishing elements 4 with pores distributed substantially at or near only the polishing surface 14 of the polishing element 4, and polishing elements 4 with substantially no pores, are contemplated within the scope of the present disclosure, and may also be advantageously fabricated.
• a porous polishing element 4 having a porous polishing surface 14 comprising a plurality of pores 15 may be used in a polishing pad according to another exemplary embodiment of the disclosure
• the porous polishing element 4 of FIG 4 is also shown with a flange 25, which may be used to facilitate bonding to a support layer (not shown in FIG. 4), for example, as illustrated in FIG. 2.
• the porous polishing element shown in FIG 4 comprises a plurality of pores 15 positioned substantially at the polishing surface 14
• the plurality of pores 15 may be distributed both throughout the entire porous polishing element 4 and at the polishing surface 14.
• the plurality of pores 15 may be distributed throughout the porous polishing element 4, but not at the polishing surface 14
• FIG 4 illustrates one particular shape of a porous polishing element 4 It will be understood that the same shape may be used to produce a substantially nonporous polishing element 4' .
• the polishing elements 4-4' may be formed in virtually any shape, and that a plurality of polishing elements 4-4' having two or more different shapes may be advantageously used and optionally arranged in a pattern before bonding to a support layer (not shown in FIG 4) used to form a polishing pad (not shown in FIG 4)
• the polishing elements 4-4' may be characterized by a height (H) and a width (W), as illustrated by FIG 4
• the cross-sectional shape of the polishing elements 4-4', taken through a polishing element 4- 4' in a direction generally parallel to the polishing surface 14, may vary widely depending on the intended application
• FIG 4 shows a generally cylindrical polishing element 4 having a generally circular cross section, other cross-sectional shapes are possible and may be desirable in certain embodiments For example, circular, elliptical, triangular, square, rectangular, and trapezoidal cross-sectional shapes may be useful
• the cross-sectional diameter of the polishing element 4 in a direction generally parallel to the polishing surface 14 is, in some embodiments, at least about
• the cross-sectional diameter of the polishing element 4 in a direction generally parallel to the polishing surface 14 is at most about 20 mm, more preferably at most about 15 mm, still more preferably at most about 12 mm
• the diameter of the polishing element, taken at the polishing surface 14 and corresponding to width (W) as shown in FIG 4 may be from about 50 ⁇ m to about 20 mm, in certain embodiments the diameter is from about 1 mm to about 15 mm, and in other embodiments the cross-sectional diameter is from about 5 mm to about 12 mm
• a characteristic dimension may be used to characterize the polishing element size in terms of a height, width, and/or length
• the characteristic dimension may be selected to be at least about 50 ⁇ m, more preferably at least about 1 mm, still
• the polishing elements (4-4' in FIGs 1-2) may be distributed on a major side of the support layer (10 in FIG 1-2) in a wide variety of patterns, depending on the intended application, and the patterns may be regular or irregular
• the polishing elements may reside on substantially the entire surface of the support layer, or there may be regions of the support layer that include no polishing elements
• the polishing elements have an average surface coverage of the support layer of at least 30%, at least 40%, or at least 50%
• the polishing elements have an average surface coverage of the support layer of at most about 80%, at most about 70%, or at most about 60% of the total area of the major surface of the support layer, as determined by the number of polishing elements, the cross-sectional area of each polishing element, and the cross-sectional area of the polishing pad
• the cross-sectional area of the polishing pad in a direction generally parallel to a major surface of the polishing pad may, in some exemplary embodiments, range from about 100 cm 2 to about 300,000 cm 2 , in other embodiments from about 1,000 cm 2 to about 100,000 cm 2 , and in yet other embodiments, from about 2,000 cm 2 to about 50,000 cm 2
• each polishing element (4-4' in FIGs 1-2) extends along the first direction substantially normal to the first major side of the support layer (10 in FIGs 1-2)
• the polishing elements extend along the first direction at least about 0 mm, 0 25 mm, at least about 0 3 mm, or at least about 0 5 mm above a plane including the optional polishing composition distribution layer (8 in FIG 1, 8' in FIG 2) and/or optional guide plate (28 in FIG 2).
• the polishing surfaces of the polishing elements may be made flush with the exposed major surface of the optional polishing composition distribution layer In other exemplary embodiments, the polishing surfaces of the polishing elements may be made recessed below the exposed major surface of the optional polishing composition distribution layer, and subsequently made flush with, or made to extend beyond, the exposed major surface of the optional polishing composition distribution layer, for example, by removal of a portion of the optional polishing composition distribution layer Such embodiments may be advantageously used with polishing composition distribution layers that are selected to be abraded or eroded during the polishing process or in optional conditioning processes applied to the polishing pad before, during, or after contact with a workpiece
• each polishing element 4-4' extends along the first direction at least about 025 mm, at least about 0 3 mm, or at least about 0 5 mm above a plane including the support layer (10 in FIGs 1-2)
• the height of the polishing surface (14 in FIGs 1-2) above the base or bottom of the polishing element that is, the height (H) of the polishing element as shown in FIG 4
• the depth and spacing of the apertures (6 in FIG 1-2) throughout the optional polishing composition distribution layer (8 in FIG 1, 8' in FIG 2) and/or optional guide plate 28 may be varied as necessary for a specific CMP process
• the polishing elements (4-4' in FIGs 1-2) are each maintained substantially in planar orientation with respect to one other and the polishing composition distribution layer (8 in FIG 1, 28 in FIG 2) and guide plate 31, and project above the surface of the optional polishing composition distribution layer (8 in FIG 1, 8' in FIG 2) and/or optional guide plate 28
• the void volume created by the extension of the polishing elements 4-4' above any optional guide plate (28 in FIG 2) and any optional polishing composition distribution layer (8 in FIG 1, 8' in FIG 2) may provide room for distribution of a polishing composition on the surface of the optional polishing composition distribution layer (8 in FIG.
• polishing elements 4-4' protrude above the polishing composition distribution layer (8 in FIG 1, 8' in FIG 2) by an amount that depends at least in part on the material characteristics of the polishing elements and the desired flow of polishing composition (working liquid and or abrasive slurry) over the surface of the polishing composition distribution layer (8 in FIG 1, 8' in FIG 2)
• the polishing elements 4-4' are porous polishing elements 4, which in certain embodiments at least have a porous polishing surface (14 in FIGs 1-2), which may make sliding or rotational contact with a substrate (not shown in FIG 1) to be polished
• the porous polishing elements may not have a porous polishing surface 14, but may have pores 15 distributed throughout substantially the entire porous polishing element 4
• Such porous polishing elements may be useful as compliant polishing elements exhibiting some of the advantageous characteristics of a compliant polishing pad Suitable porous polishing elements are disclosed in co-pending U S Provisional Patent Application No 61/075970, filed June 26, 2008, titled "POLISHING PAD WITH POROUS ELEMENTS AND METHOD OF MAKING AND USING THE SAME"
• one or more of the porous polishing elements 4 may comprise a plurality of pores 15 distributed throughout substantially the entire polishing element 4 in the form of a porous foam
• the foam may be a closed cell foam, or an open cell foam Closed cell foams may be preferred in some embodiments
• the plurality of pores 15 in the foam exhibits a unimodal distribution of pore size, for example, pore diameter
• the plurality of pores exhibits a mean pore size of at least about 1 nanometer (nm), at least about 100 nm, at least about 500 nm, or at least about 1 ⁇ m
• the plurality of pores exhibits a mean pore size of at most about 100 ⁇ m, at most about 50 ⁇ m, at most about 10 ⁇ m, or at most about 1 ⁇ m
• the plurality of pores exhibits a mean pore size from about 1 ⁇ m to about 50 ⁇ m Referring now to FIGs 1-2 and
• each porous polishing element 4-4' may be a substantially flat surface, or may be textured
• at least the polishing surface of each porous polishing element is made porous, for example with microscopic surface openings or pores 15, which may take the form of orifices, passageways, grooves, channels, and the like
• Such pores 15 at the polishing surface may act to facilitate distributing and maintaining a polishing composition (e g , a working liquid and/or abrasive polishing slurry not shown in the figures) at the interface between a substrate (not shown) and the corresponding porous polishing elements
• the polishing surface 14 comprises pores 15 that are generally cylindrical capillaries.
• the pores 15 may extend from the polishing surface 14 into the polishing element 4
• the polishing surface comprises pores 15 that are generally cylindrical capillaries extending from the polishing surface 14 into the porous polishing element 4.
• the pores need not be cylindrical, and other pore geometries are possible, for example, conical, rectangular, pyramidal, and the like
• the characteristic dimensions of the pores can, in general, be specified as a depth, along with a width (or diameter), and a length
• the characteristic pore dimensions may range from about 25 ⁇ m to about 6,500 ⁇ m in depth, from about 5 ⁇ m to about 1000 ⁇ m in width (or diameter), and from about 10 ⁇ m to about 2,000 ⁇ m in length
• the polishing surface comprises pores in the form of a plurality of channels, wherein each channel extends across at least a portion of the polishing surface of a corresponding polishing element, preferably in a direction generally parallel to the polishing surface Preferably, each channel extends across the entire polishing surface of a corresponding polishing element in a direction generally parallel to the polishing surface.
• the pores may take the form of a two-dimensional array of channels in which each channel extends across only a portion of the polishing surface
• the channels may have virtually any shape, for example, cylindrical, triangular, rectangular, trapezoidal, hemispherical, and combinations thereof
• the depth of each channel in a direction substantially normal to the polishing surface of the polishing elements is selected to be in the range of at least about 100 ⁇ m to about 7500 ⁇ m
• the cross-sectional area of each channel in a direction substantially parallel to the polishing surface of the polishing elements is selected to be in the range from about 75 square micrometers ( ⁇ m 2 ) to about 3 x 10 6 ⁇ m 2 .
• the support layer may be substantially incompressible, such as a rigid film or other hard substrate, but is preferably compressible to provide a positive pressure directed toward the polishing surface
• the support layer may comprise a flexible and compliant material, such as a compliant rubber or polymer
• the support layer is preferably made of a compressible polymeric material, foamed polymeric materials being preferred
• closed cell foams may be preferred, although in other embodiments, and open cell foam may be used
• the polishing elements may be formed with the support layer as a unitary sheet of polishing elements affixed to the support layer, which may be a compressible or compliant support layer
• the support layer is preferably liquid impermeable, to prevent penetration or permeation of a working liquid into or through the support layer
• the support layer may comprise liquid permeable materials, alone or in combination with an optional barrier that acts to prevent or inhibit liquid penetration or permeation through the support layer
• a porous support layer may be used advantageously, for example, to retain a working liquid (e g , a polishing slurry) at the interface between the polishing pad and a workpiece during polishing
• the support layer may comprise a polymeric material selected from silicone, natural rubber, styrene-butadiene rubber, neoprene, polyurethane, polyester, polyethylene, and combinations thereof
• the support layer may further comprise a wide variety of additional materials, such as fillers, particulates, fibers, reinforcing agents, and the like
• the support layer is a film comprising one or more TPU, for example, an ESTANE TPU (available from Lubrizol Advanced Materials, Inc , Cleveland, OH), a TEXIN or DESMOPAN TPU (available from Bayer Material Science, Pittsburgh, PA), a PELLETHANE TPU (available from Dow Chemical Company, Midland, MI), and the like
• the polishing elements may comprise a wide variety of materials, with polymeric materials being preferred Suitable polymeric materials include, for example, polyurethanes, polyacrylates, polyvinyl alcohol polyesters, polycarbonates, and acetals available under the trade designation DELRIN (available from E I. DuPont de Nemours, Inc , Wilmington, DE)
• Suitable polymeric materials include, for example, polyurethanes, polyacrylates, polyvinyl alcohol polyesters, polycarbonates, and acetals available under the trade designation DELRIN (available from E I. DuPont de Nemours, Inc , Wilmington, DE)
• at least some of the polishing elements comprise a thermoplastic polyurethane, a polyacrylate, polyvinyl alcohol, or combinations thereof
• polishing elements may also comprise a reinforced polymer or other composite material, including, for example, metal particulates, ceramic particulates, polymeric particulates, fibers, combinations thereof, and the like
• polishing elements may be made electrically and/or thermally conductive by including therein fillers such as, carbon, graphite, metals or combinations thereof
• electrically conductive polymers such as, for example, polyanilines (PANI) sold under the trade designation ORMECOM (available from Ormecon Chemie, Ammersbek, Germany) may be used, with or without the electrically or thermally conductive fillers referenced above
• the polishing pad further comprises a compliant layer affixed to the support layer opposite the polishing elements
• the compliant layer may be affixed to the support layer by any means of bonding surfaces, but preferably, an adhesive layer positioned at an interface between the compliant layer and the support layer is used to affix the support layer to the compliant layer opposite the polishing elements
• the compliant layer is preferably compressible to provide a positive pressure directing the polishing surfaces of the polishing elements toward a workpiece during polishing
• the support layer may comprise a flexible and compliant material, such as a compliant rubber or polymer
• the support layer is preferably made of a compressible polymeric material, foamed polymeric materials being preferred
• closed cell foams may be preferred, although in other embodiments, and open cell foam may be used
• the compliant layer may comprise a polymeric material selected from silicone, natural rubber, styrene-butadiene rubber, neoprene, polyurethane, polyethylene, and combinations thereof
• the compliant layer may further comprise a wide variety of additional materials, such as fillers, particulates, fibers, reinforcing agents, and the like
• the compliant layer is preferably liquid impermeable (although permeable materials may be used in combination with an optional barrier to prevent or inhibit liquid penetration into the compliant layer
• Preferred polymeric materials for use in the compliant layer are polyurethanes, with TPUs being particularly preferred Suitable polyurethanes include, for example, those available under the trade designation PORON from Rogers Corp , Rogers, CT, as well as those available under the trade designation PELLETHANE from Dow Chemical, Midland, MI, particularly PELLETHANE 2102-65D
• Other suitable materials include polyethylene terepthalates (PET), such as, for example biaxially oriented PET widely available under the trade designation
• decoupling of the polishing surfaces of the polishing elements from the compliant underlayer may be augmented by incorporating into the polishing article an optional guide plate including a plurality of apertures extending through the guide plate from a first major surface to a second major surface, wherein at least a portion of each polishing element extends into a corresponding aperture, and wherein each polishing element extends outwardly from the second major surface of the guide plate
• the optional guide plate which preferably comprises a stiff or non-compliant material, may be used to maintain the spatial orientation of polishing surface, as well as to maintain lateral movement of the elements on the polishing pad In other embodiments, however, the optional guide plate is not required, because the spatial orientation of the polishing elements is maintained and lateral movement is prevented by bonding the elements to the support layer, preferably by thermally bonding the polishing elements directly to the support layer
• the optional guide plate can be made of a wide variety of materials, such as polymers, copolymers, polymer blends, polymer composites, or combinations thereof A rigid
• the optional polishing composition distribution layer comprises a compliant material, for example, a porous polymer or foam, to provide a positive pressure directed toward to substrate during polishing operations when the polishing composition distribution layer is compressed
• the compliance of the polishing composition distribution layer is selected to be less than the compliance of the optional compliant layer
• Porous or foamed materials with open or closed cells may be preferred compliant materials for use in an optional polishing composition distribution layer in certain embodiments
• the optional polishing composition distribution layer has between about 10 and about 90 percent porosity
• the polishing surfaces of the polishing elements may be made flush with or recessed below the exposed major surface of the optional polishing composition distribution layer Such embodiments may be advantageously employed to maintain a working liquid, for example a polishing slurry, at the interface between the exposed polishing surfaces of the polishing elements and a workpiece
• the polishing composition distribution may be advantageously selected to comprise a material that is abraded or eroded during the polishing process or in optional conditioning processes applied to the polishing surface of the polishing pad before, during, or after contact with a workpiece
• the polishing composition distribution layer may act to substantially uniformly distribute a polishing composition across the surface of the substrate undergoing polishing, which may provide more uniform polishing
• the polishing composition distribution layer may optionally include flow resistant elements such as baffles, grooves (not shown in the figures), pores, and the like, to regulate the flow rate of the polishing composition during polishing
• the polishing composition distribution layer can include various layers of different materials to achieve desired polishing composition flow rates at varying depths from the polishing surface
• one or more of the polishing elements may include an open core region or cavity defined within the polishing element, although such an arrangement is not required
• the core of the polishing element can include sensors to detect pressure, conductivity, capacitance, eddy currents, and the like
• the polishing pad may include a window extending through the pad in the direction normal to the polishing surface, or may use transparent layers and/or transparent polishing elements, to allow for optical end-pointing of a polishing process, as described in the co-pending U S
• transparent layer is intended to include a layer that comprises a transparent region, which may be made of a material that is the same or different from the remainder of the layer
• the element, layer or region may be transparent, or may be made transparent by applying heat and/or pressure to the material, or a transparent material may be cast in place in an aperture suitably positioned in a layer to create a transparent region
• the entire support layer may be made of a material that is or may be made transparent to energy in the range of wavelength(s) of interest utilized by an endpoint detection apparatus
• Preferred transparent materials for a transparent element, layer or region include, for example, transparent polyurethanes
• the term “transparent” is intended to include an element, layer, and or region that is substantially transparent to energy in the range of wavelength(s) of interest utilized by an endpoint detection apparatus
• the endpoint detection apparatus uses one or more source of electromagnetic energy to emit radiation in the form of ultraviolet light, visible light, infrared light, microwaves, radio waves, combinations thereof, and the like
• the term “transparent” means that at least about 25% (e g , at least about 35%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%) of energy at a wavelength of interest that impinges upon the transparent element, layer or region is transmitted therethrough
• the support layer is transparent In certain exemplary embodiments, at least one polishing element is transparent In additional exemplary embodiments, at least one polishing element is transparent, and the adhesive layer and the support layer are also transparent In further exemplary embodiments, the support layer, the guide plate, the polishing composition distribution layer, at least one polishing element, or a combination thereof is transparent
• the present disclosure is further directed to a method of using a polishing pad as described above in a polishing process, the method including contacting a surface of a substrate with a polishing surface of a polishing pad comprising a plurality of polishing elements, at least some of which are porous, and relatively moving the polishing pad with respect to the substrate to abrade the surface of the substrate
• a working liquid may be provided to an interface between the polishing pad surface and the substrate surface Suitable working liquids are known in the art, and may be found, for example, in U S Patent Nos 6,238,592 Bl, 6,491,843 Bl, and WO/200233736
• a method of making a polishing pad comprising forming a plurality of polishing elements, and bonding the polishing elements to a support layer to form a polishing pad
• Bonding of the polishing elements to the support layer may, in some embodiments, comprise thermal bonding, or use of a bonding material to effect adhesive bonding, actinic radiation bonding, or combinations thereof
• the polishing elements are thermally bonded to the support layer
• Thermal bonding may be achieved, for example, by contacting a major surface of the support layer with a surface of each polishing element to form a bonding interface, and heating the polishing elements and the support layer to a temperature at which the polishing elements and support layer soften, melt, or flow together to form a bond at the bonding interface
• bonding the polishing elements to the support layer involves using a bonding material that forms a physical and/or chemical union at an interface between the polishing elements and a major surface of the support layer
• a bonding material that forms a physical and/or chemical union at an interface between the polishing elements and a major surface of the support layer
• the bonding material may be a material that forms a bond by curing, for example, by thermally curing, radiation curing (e.g , curing using actinic radiation such as ultraviolet light, visible light, infrared light, electron beams or other radiation sources), and the like
• at least some of the polishing elements are substantially non-porous polishing elements
• at least a portion of the polishing elements may be porous polishing elements
• the method includes forming the porous polishing elements by injection molding of a gas saturated polymer melt, injection molding of a reactive mixture that evolves
• the porous polishing elements have pores distributed substantially throughout the entire polishing element In other embodiments, the pores may be distributed substantially at the polishing surface of the porous polishing elements In some additional embodiments, the porosity imparted to the polishing surface of a porous polishing element may be imparted, for example, by injection molding, calendaring, mechanical drilling, laser drilling, needle punching, gas dispersion foaming, chemical processing, and combinations thereof It will be understood that the polishing pad need not comprise only substantially identical polishing elements Thus, for example, any combination or arrangement of porous polishing elements and non-porous polishing elements may make up the plurality of porous polishing elements It will also be understood that any number, combination or arrangement of porous polishing elements and substantially nonporous polishing elements may be used advantageously in certain embodiments to form a polishing pad having floating polishing elements bonded to a support layer
• the polishing elements may be arranged to form a pattern Any pattern may be advantageously employed
• the polishing elements may be arranged to form a two-dimensional array, for example, a rectangular, triangular, or circular array of polishing elements
• the polishing elements may include both porous polishing elements and substantially nonporous polishing elements arranged in a pattern on the support layer
• the porous polishing elements may be advantageously arranged with respect to any substantially nonporous polishing elements to form an arrangement of porous polishing elements and nonporous polishing elements on the major surface of the support layer
• the number and arrangement of porous polishing elements relative to substantially nonporous polishing elements may be selected advantageously to obtain desirable polishing performance
• the porous polishing elements may be arranged substantially near the center of a major surface of the polishing pad, and substantially nonporous polishing elements may be arranged substantially near the peripheral edge of the major surface of the polishing pad
• exemplary embodiments may desirably more effectively retain a working liquid, for example an abrasive polishing slurry, in the contact zone between the polishing pad and the wafer surface, thereby improving wafer surface polishing uniformity (e g , reduced dishing at the wafer surface) as well as reducing the quantity of waste slurry generated by the CMP process
• Such exemplary embodiments may also desirably provide more aggressive polishing at the edges of the die, thereby reducing or eliminating the formation of an edge ridge, and improving yield and die polish uniformity.
• the porous polishing elements may be arranged substantially near the edge of a major surface of the polishing pad, and substantially nonporous polishing elements may be arranged substantially near the center of the major surface of the polishing pad
• Other arrangements and/or patterns of polishing elements are contemplated as falling within the scope of the present disclosure
• the polishing elements may be arranged in a pattern by placement on a major surface of the support layer
• the polishing elements may be arranged in a pattern using a template of the desired pattern, and the support layer may be positioned over or under the polishing elements and the template prior to bonding, with a major surface of the support layer contacting each polishing element at a bonding interface
• polishing pads having polishing elements according to the present disclosure may have various features and characteristics that enable their use in a variety of polishing applications
• polishing pads of the present disclosure may be particularly well suited for chemical mechanical planarization (CMP) of wafers used in manufacturing integrated circuits and semiconductor devices
• CMP chemical mechanical planarization
• the polishing pad described in this disclosure may provide advantages over polishing pads that are known in the art
• a polishing pad according to the present disclosure may act to better retain a working liquid used in the CMP process at the interface between the polishing surface of the pad and the substrate surface being polished, thereby improving the effectiveness of the working liquid in augmenting polishing.
• a polishing pad according to the present disclosure may reduce or eliminate dishing and/or edge erosion of the wafer surface during polishing.
• use of a polishing pad according to the present disclosure in a CMP process may result in improved within wafer polishing uniformity, a flatter polished wafer surface, an increase in edge die yield from the wafer, and improved CMP process operating latitude and consistency
• polishing pad with porous elements may permit processing of larger diameter wafers while maintaining the required degree of surface uniformity to obtain high chip yield, processing of more wafers before conditioning of the pad surface is required in order to maintain polishing uniformity of the wafer surface, or reducing process time and wear on the pad conditioner Exemplary polishing pads according to the present disclosure will now be illustrated with reference to the following non-limiting examples
• Example IA nonporous polishing elements
• Example IB porous polishing elements
• the porous polishing elements were prepared by injection molding of a mixture comprising a polymer dissolved in a supercritical gas
• the polymer melt was injection molded into a 32-cavity, cold runner mold (solid shot weight of 9 2 grams) to form substantially nonporous polishing elements having a hollow internal cylindrical cavity and weighing 0 15 grams/element
• nitrogen gas was injected under elevated temperature and pressure into the polymer melt using a Trexel SII-TRlO outfitted with a Mass Pulse Dosing delivery system (available from Trexel, Inc , Woburn, MA), resulting in formation of a 0
• This example illustrates the preparation of a porous polishing element in which pores are distributed substantially only at the polishing surface of the element
• Nonporous polishing elements were first prepared by injection molding a thermoplastic polyurethane (ESTANE ETE 60DT3 NAT 022P, Lubrizol Advanced
• polishing surface of an injection molded polishing element was then laser drilled to form a porous polishing element using an AVIA 355 nm ultraviolet laser
• thermoplastic polyurethane melt was injection molded into a 2-cavity, cold runner mold (shot weight of 34 01 grams) equipped with a ribbed mold insert in one cavity and a blank mold insert in the other cavity
• injection molding conditions are summarized in Table 2
• Figure 5 illustrates one exemplary apparatus useful in the method for thermal bonding of polishing elements to a support layer
• a multiplicity of nonporous polishing elements 4' may be arranged in a two-dimensional array pattern in template 30 (see
• FIG 3A positioned on release layer 34
• Support layer 10 may be laid over the exposed surfaces of the polishing elements 4'
• Release layer 34' may be placed over the exposed surface of the support layer 10, and the entire assembly may be placed between the upper platen 36 and lower platen 38 of a heated press
• the support layer 10 may be placed on release layer 34 and overlaid with the template 30 before arranging the nonporous polishing elements 4 in a two-dimensional array pattern in the template, and overlaying the arranged elements with release layer 34'
• porous polishing elements 4 may be substituted for nonporous polishing elements 4' in any number, arrangement or combination
• Example 4 illustrates a method of thermally bonding injection molded thermoplastic polyurethane polishing elements prepared according to Example 1 to a support layer film comprising a thermoplastic polyurethane Polishing elements (15 mm diameter) were formed by injection molding a thermoplastic polyurethane (TPU), ESTANE 58144 (available from Lubrizol Advanced Materials, Inc , Cleveland, OH) according to Example 1
• the polishing elements were arranged in a generally circular two-dimensional array pattern using a polycarbonate template as shown in FIG 6, and bonded to a 26 ⁇ m thick support layer formed by extrusion of a thermoplastic polyurethane (TPU), ESTANE 58887-NAT02 (available from Lubrizol Advanced Materials, Inc , Cleveland, OH) into film form at 182°C
• Thermal bonding was carried out in a heated platen press (Pasadena Hydraulics Press Company, El Monte, CA) substantially as shown in FIG 5
• the upper platen was maintained at approximately 143 3°C
• the lower platen was maintained at approximately 26 7°C
• Sufficient pressure was applied to make contact between the TPU polishing elements and the TPU support layer, which were positioned between paper release liners as shown in FIG 5 Bonding was substantially complete and uniform after 30 seconds
• the paper liners were removed to yield a clear integral sheet of TPU support layer with thermally bonded TPU polishing elements, as shown in FIG 7
• Example 5 illustrates the method of thermally bonding injection molded thermoplastic polyurethane polishing elements prepared according to Example 1 to a support layer film comprising a different thermoplastic polyurethane
• Polishing elements (6 mm diameter) were formed by injection molding a TPU
• polishing elements were arranged in a generally circular two-dimensional array pattern using a polycarbonate template (FIG 6), and thermally bonded to a 122 ⁇ m thick TPU film support layer (Stevens Urethane ST-1522CL,
• Thermal bonding was carried out in a heated platen press (HK N-800 single platen press, Pittsburgh, KS) substantially as shown in FIG 5
• the upper platen was maintained at approximately 149°C, and the lower platen was maintained at approximately 26 7 0 C
• a pressure of 40 psi (about 275,790 Pa) was applied to the TPU polishing elements and the
• TPU support layer which were positioned between paper release liners as shown in FIG 5 Bonding was substantially complete and uniform after 15 seconds After thermally bonding the TPU support layer to the TPU polishing elements, the paper liners were removed to yield a clear integral sheet of TPU support layer with thermally bonded TPU polishing elements.
• Example 6 illustrates an alternate method of thermally bonding injection molded thermoplastic polyurethane polishing elements prepared according to Example 1 to a support layer film comprising polyester Polishing elements (15 mm diameter) were formed by injection molding a TPU
• Example 2 (ESTANE 58144, available from Lubrizol Advanced Materials, Inc , Cleveland, OH) according to Example 1
• the polishing elements were arranged directly on a major surface of the support layer, a 102 ⁇ m thick polyester film (3M Thermo-Bond 615 Film, 3M Company, St Paul, MN), and thermally bonded to the support layer Thermal bonding was carried out in a heated platen press (Pasadena Hydraulics
• the upper platen was maintained at approximately 121 0 C, and the lower platen was maintained at approximately 26 7°C Sufficient pressure was applied to make contact between the TPU polishing elements and the support layer, which were positioned between paper release liners Bonding was substantially complete and uniform after 20 seconds After thermally bonding the support layer to the TPU polishing elements, the paper liners were removed to yield a clear integral sheet of support layer with thermally bonded TPU polishing elements
• Example 7 illustrates the method of thermally bonding injection molded thermoplastic polyurethane polishing elements prepared according to Example 1 to a support layer comprising a different polyester film
• Polishing elements (15 mm diameter) were formed by injection molding a TPU
• Example 2 (ESTANE 58144, available from Lubrizol Advanced Materials, Inc , Cleveland, OH) according to Example 1
• the polishing elements were arranged directly on a major surface the support layer, a 102 ⁇ m thick polyester film (3M Thermo-Bond 668 Film, 3M
• Thermal bonding was carried out in a heated platen press (HIX N-800 single platen press, Pittsburgh, KS) The upper platen was maintained at approximately 149°C, and the lower platen was maintained at approximately 26 7 0 C A pressure of 40 psi (about 275,790 Pa) was applied to the TPU polishing elements and the support layer, which were positioned between paper release liners Bonding was substantially complete and uniform after 15 seconds
• Example 8 illustrates a method of thermally bonding an integral film comprising polishing elements bonded to a support layer to a compliant layer to form a polishing pad having floating elements
• FIG 8 is a photograph of a polishing pad comprising floating polishing elements bonded to a support layer, wherein the support layer is affixed to a compliant sub-layer with an adhesive, and wherein a pressure sensitive adhesive is adhered to the compliant sub-layer on a major surface opposite the polishing elements, according to yet another exemplary embodiment of the disclosure
• the polishing pad of Example 8 was mounted to an aluminum polishing platen using the Transfer Tape pressure sensitive adhesive on the bottom surface of the compliant foam sub-layer
• the polishing platen with polishing pad was then mounted in a CETR Polisher (CP-4, Center for Tribology, Inc, Campbell, CA), placed into contact with a diamond pad dresser (3M Sintered Abrasive Conditioner A3800) and stressed under various conditions (see Table 1) in deionized water for 5 minutes
• the pad was inspected for element debonding and none was detected
• the pad was ran until the tops were wore off at 8 lb f (about 3,632 g f ), 60 rpm table and platen speed and 10 mm oscillation (4 cycles/min). Throughout the test, the pad was periodically checked for polishing element de-bonding, and none was detected
• Table 3 The test conditions are summarized in Table 3
• polishing pads according to exemplary embodiments need not comprise only substantially identical polishing elements
• any combination or arrangement of porous polishing elements and non-porous polishing elements may make up the plurality of porous polishing elements
• any number, combination or arrangement of porous polishing elements and substantially nonporous polishing elements may be used advantageously in certain embodiments to form a polishing pad having floating polishing elements bonded to a support layer.
• a multi-cavity mold may be provided with a back-fill chamber, wherein each cavity corresponds to a polishing element.
• a plurality of polishing elements which may include porous polishing elements and nonporous polishing element as described herein, may be formed by injection molding a suitable polymer melt into the multi-cavity mold, and back-filling the back-fill chamber with the same polymer melt or another polymer melt to form a support layer The polishing elements remain affixed to the support layer upon cooling of the mold, thereby forming a plurality of polishing elements as a unitary sheet of polishing elements with the support layer

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• Engineering & Computer Science (AREA)
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• Manufacturing & Machinery (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

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• 2009
  • 2009-07-17 CN CN200980136821.5A patent/CN102159361B/zh not_active Expired - Fee Related
  • 2009-07-17 JP JP2011518940A patent/JP5450622B2/ja not_active Expired - Fee Related
  • 2009-07-17 TW TW098124300A patent/TWI415711B/zh not_active IP Right Cessation
  • 2009-07-17 KR KR1020117003722A patent/KR20110033277A/ko not_active Application Discontinuation
  • 2009-07-17 EP EP09790596.2A patent/EP2323808B1/de not_active Not-in-force
  • 2009-07-17 US US13/054,691 patent/US20110183583A1/en not_active Abandoned
  • 2009-07-17 WO PCT/US2009/051032 patent/WO2010009420A1/en active Application Filing

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