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Publication numberUS20040259479 A1
Publication typeApplication
Application numberUS 10/601,601
Publication dateDec 23, 2004
Filing dateJun 23, 2003
Priority dateJun 23, 2003
Also published asCN1809445A, EP1638733A1, WO2005000525A1
Publication number10601601, 601601, US 2004/0259479 A1, US 2004/259479 A1, US 20040259479 A1, US 20040259479A1, US 2004259479 A1, US 2004259479A1, US-A1-20040259479, US-A1-2004259479, US2004/0259479A1, US2004/259479A1, US20040259479 A1, US20040259479A1, US2004259479 A1, US2004259479A1
InventorsRoland Sevilla
Original AssigneeCabot Microelectronics Corporation
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Polishing pad for electrochemical-mechanical polishing
US 20040259479 A1
Abstract
The invention provides a polishing pad comprising a body having a top surface comprising a first set of grooves with a first depth and first width and a bottom surface comprising a second set of grooves with a second depth and second width, wherein the first set of grooves and second set of grooves are interconnected and are oriented such that they are not aligned.
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Claims(26)
What is claimed is:
1. A polishing pad comprising a body having (a) a top surface comprising a first set of grooves with a first depth and first width and (b) a bottom surface comprising a second set of grooves with a second depth and second width, wherein the first set of grooves and second set of grooves are interconnected and are oriented such that they are not aligned.
2. The polishing pad of claim 1, wherein the first and second sets of grooves have a cross-sectional shape selected from the group consisting of lines, curves, circles, ovals, squares, rectangles, triangles, diamonds, and combinations thereof.
3. The polishing pad of claim 2, wherein the grooves are linear grooves.
4. The polishing pad of claim 3, wherein the first and second sets of grooves are non-parallel.
5. The polishing pad of claim 1, wherein the polishing pad has a void volume of about 30% or more.
6. The polishing pad of claim 5, wherein the polishing pad has a void volume of about 70% or more.
7. The polishing pad of claim 1, wherein the first set of grooves is rotated by an angle of about 10° to about 90° relative to the second set of grooves.
8. The polishing pad of claim 7, wherein the angle is about 90°.
9. The polishing pad of claim 1, wherein a first depth of the first set of grooves and a second depth of the second set of grooves combine to have a total groove depth that is about equal to or greater than the thickness of the polishing pad.
10. The polishing pad of claim 9, wherein the first set of grooves and second set of grooves are interconnected by primary channels that are oriented perpendicular to the top surface of the polishing pad.
11. The polishing pad of claim 10, further comprising a plurality of secondary channels extending through the thickness of the polishing pad.
12. The polishing pad of claim 1, wherein a first groove depth of the first set of grooves and a second groove depth of the second set of grooves combine to have a total groove depth that is less than the thickness of the polishing pad.
13. The polishing pad of claim 12, wherein the first and second sets of grooves are interconnected by a plurality of secondary channels extending through the thickness of the polishing pad.
14. The polishing pad of claim 1, wherein the first set of grooves, the second set of grooves, or a combination thereof have an average groove width of about 0.1 mm to about 2 mm.
15. The polishing pad of claim 1, wherein the first groove width and the second groove width increase from one side of the polishing pad to the other side of the polishing pad.
16. The polishing pad of claim 1, wherein the body comprises a polymer resin selected from the group consisting of thermoplastic elastomers, thermoplastic polyurethanes, thermoplastic polyolefins, polycarbonates, polyvinylalcohols, nylons, elastomeric rubbers, elastomeric polyethylenes, polytetrafluoroethylenes, polyethyleneterephthalates, polyimides, polyaramides, polyarylenes, polyacrylates, polystyrenes, polymethylmethacrylates, copolymers thereof, and mixtures thereof.
17. The polishing pad of claim 16, wherein the polymer resin is a thermoplastic polyurethane resin.
18. The polishing pad of claim 1, wherein the body of the polishing pad further comprises abrasive particles.
19. The polishing pad of claim 1, wherein the polishing pad is conductive.
20. The polishing pad of claim 19, wherein the body of the polishing pad further comprises conductive elements.
21. The polishing pad of claim 19, wherein the body of the polishing pad further comprises a conductive polymer.
22. A method of polishing a substrate by electrochemical-mechanical polishing comprising:
(i) providing an electrochemical-mechanical polishing (ECMP) apparatus comprising the polishing pad of claim 1,
(ii) providing a substrate to be polished
(iii) supplying the ECMP apparatus with an electrolytically conductive fluid,
(iv) applying an electrochemical potential to a surface of the substrate, and
(v) moving the polishing pad relative to the substrate to abrade the substrate and thereby polish the substrate.
23. The method of claim 22, wherein the electrochemical potential is varied over time.
24. The method of claim 22, wherein the electrolytically conductive fluid is supplied by one or more pumps.
25. The method of claim 22, wherein the electrolytically conductive fluid comprises gas bubbles.
26. The method of claim 22, wherein the polishing pad is conductive.
Description
FIELD OF THE INVENTION

[0001] This invention pertains to a polishing pad for use in electrochemical-mechanical polishing.

BACKGROUND OF THE INVENTION

[0002] Polishing processes are used in the manufacturing of microelectronic devices to form flat surfaces on semiconductor wafers, field emission displays, and many other microelectronic substrates. For example, the manufacture of semiconductor devices generally involves the formation of various process layers, selective removal or patterning of portions of those layers, and deposition of yet additional process layers above the surface of a semiconducting substrate to form a semiconductor wafer. The process layers can include, by way of example, insulation layers, gate oxide layers, conductive layers, and layers of metal or glass, etc. It is generally desirable in certain steps of the wafer process that the uppermost surface of the process layers be planar, i.e., flat, for the deposition of subsequent layers. Polishing processes such as chemical-mechanical polishing (“CMP”) are used to planarize process layers wherein a deposited material, such as a conductive or insulating material, is polished to planarize the wafer for subsequent process steps.

[0003] Copper is increasingly used in the manufacture of microelectronic devices due to its desirable electrical properties. Techniques such as damascene or dual damascene processes are currently used in the manufacture of copper substrate features. In a damascene process, a feature is defined in a dielectric material, a barrier layer material is deposited over the surfaces of the features, and copper is deposited over the barrier layer and surrounding field. Such a process results in the deposition of excess copper on the substrate surface that must be removed (e.g., by polishing) before subsequent processing.

[0004] The removal of excess copper is challenged by the fact that the interface between the conductive material and the barrier layer is generally non-planar. Residual copper can be retained in irregularities formed by the non-planar interface. Conductive and barrier materials are often removed from the substrate surface at different rates, which can result in excess conductive material being retained as residues on the substrate surface. Additionally, the substrate surface can have a varied surface topography, depending on the density or size of features formed therein, which results in different copper removal rates along the different surface topography of the substrate surface. All of these aspects make effective removal of copper from the substrate surface and final planarity of the substrate surface difficult to achieve.

[0005] All of the desired copper from the substrate surface can be removed by overpolishing the substrate surface. However, overpolishing can result in topographical defects, such as concavities or depressions in features (“dishing”) or excessive removal of dielectric material (“erosion”). The topographical defects from dishing and erosion can further lead to non-uniform removal of other layers, such as the barrier layer disposed thereunder.

[0006] The use of low dielectric constant (low-κ) materials to form copper damascenes in the substrate surface gives rise to another problem with the polishing of copper surfaces. Low-κ dielectric materials, such as carbon-doped silicon oxides, can deform or fracture under conventional polishing downforce pressures (i.e., about 40 kPa), which can detrimentally affect substrate polish quality and device formation. For example, relative rotational movement between the substrate and a polishing pad can induce a shear force along the substrate surface and deform the low-K material to form topographical defects.

[0007] An approach to minimize polishing defects in substrates comprising copper and low-K dielectric materials is to polish the copper using electrochemical-mechanical polishing (ECMP). ECMP can remove conductive material from a substrate surface by electrochemical dissolution while concurrently polishing the substrate with reduced mechanical abrasion compared to conventional CMP processes. The electrochemical dissolution is performed by applying a bias between a cathode and the substrate surface to remove conductive materials from a substrate surface into a surrounding electrolyte solution or slurry. In one embodiment of an ECMP system, the bias is applied by a ring of conductive contacts in electrical communication with the substrate surface in a substrate support device, such as a substrate carrier head. However, the contact ring has been observed to exhibit non-uniform distribution of current over the substrate surface, which results in non-uniform dissolution. Mechanical abrasion is performed by positioning the substrate in contact with a conventional polishing pad and providing relative motion therebetween. However, conventional polishing pads often restrict the flow of electrolyte solution to the surface of the substrate. Additionally, the polishing pad may be composed of insulating materials that can interfere with the application of bias to the substrate surface and result in non-uniform or variable dissolution of material from the substrate surface.

[0008] As a result, there is a need for an improved polishing pad for the removal of conductive material on a substrate surface during ECMP. The invention provides such a polishing pad. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

BRIEF SUMMARY OF THE INVENTION

[0009] The invention provides a polishing pad comprising a body having a top surface comprising a first set of grooves and a bottom surface comprising a second set of grooves, wherein the first set of grooves and second set of grooves are interconnected and are oriented such that they are not aligned. The invention further provides a method of electrochemical-mechanical polishing comprising the use of the polishing pad.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1A is a fragmentary, partially cross-sectional perspective view depicting a polishing pad of the invention having a top surface (10) comprising a first set of linear grooves (12) and a bottom surface (14) comprising a second set of linear grooves (16) that are oriented 90° with respect to the first set of grooves, wherein the intersection of the first and second sets of grooves produces primary channels (20).

[0011]FIG. 1B is a fragmentary top view depicting a polishing pad of the invention comprising a first set of linear grooves (12) and a second set of linear grooves (16) that are oriented 90° with respect to the first set of grooves, wherein the intersection of the first and second sets of grooves produces primary channels (20).

[0012]FIG. 2 is a fragmentary top view depicting a polishing pad of the invention comprising a first set of curved grooves (12) and a second set of curved grooves (16) that are oriented 45° with respect to the first set of grooves, wherein the intersection of the first and second sets of grooves produces primary channels (20).

[0013]FIG. 3 is a fragmentary top view depicting a polishing pad of the invention comprising a first set of circular grooves (12) and a second set of circular grooves (16) that are displaced by a distance that is half the diameter of the circular groove, wherein the intersection of the first and second sets of grooves produces primary channels (20).

[0014]FIG. 4 is a fragmentary top view depicting a polishing pad of the invention comprising a first set of linear grooves (12), a second set of linear grooves (16), and secondary channels (22).

[0015]FIG. 5A is a fragmentary, partially cross-sectional perspective view depicting a polishing pad of the invention having a top surface (10) comprising a first set of linear grooves (12) and a bottom surface (14) comprising a second set of linear grooves (16) that are oriented 90° with respect to the first set of grooves, wherein the intersection of the first and second sets of grooves produces primary channels (20), and the polishing pad further comprises secondary channels (22).

[0016]FIG. 5B is a fragmentary top view depicting a polishing pad of the invention comprising a first set of linear grooves (12) and a second set of linear grooves (16) that are oriented 90° with respect to the first set of grooves, wherein the polishing pad further comprises primary channels (20) and secondary channels (22).

[0017]FIG. 6 is a fragmentary top view depicting a polishing pad of the invention comprising a first set of linear grooves (12) and a second set of linear grooves (16) that are oriented 90° with respect to the first set of grooves, wherein the widths of the first and second sets of grooves increase from one side of the polishing pad to the other.

[0018]FIG. 7 is a cross-sectional view of an electrochemical-mechanical polishing apparatus comprising a polishing pad of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0019] The invention is directed to a polishing pad for use in electrochemical-mechanical polishing (“ECMP”). The polishing pad comprises a body having a top surface and a bottom surface. Both the top surface and bottom surface are grooved. The top surface comprises a first set of grooves and the bottom surface comprises a second set of grooves. The first and second sets of grooves are interconnected. Desirably, the first and second sets of grooves are oriented with respect to each other so as to provide maximum flow of electrolyte across and through the body of the polishing pad and to provide maximum uniformity of the electrolyte flow throughout the body of the polishing pad.

[0020] The grooves can have any suitable cross-sectional shape. For example, the cross-sectional shape of the first and second sets of grooves can consist of lines (e.g., parallel lines, XY crosshatch), curves, circles (e.g., concentric circles), ovals, squares, rectangles, triangles, diamonds, or combinations thereof. The cross-sectional shape of the first set of grooves can be the same or different from the cross-sectional shape of the second set of grooves. In addition, the first and second sets of grooves can each comprise a combination of different cross-sectional groove shapes. Preferably, at least one of the first and second sets of grooves comprises linear grooves. More preferably, both the first and second sets of grooves comprise, consist essentially of, or consist of linear grooves.

[0021] The first and second sets of grooves are oriented such that they are not aligned. Accordingly, the first and second sets of grooves should not substantially or completely overlay one another. The first and second sets of grooves should be oriented relative to each other such that they would intersect (e.g., cross) if they were to occupy the same plane of the polishing pad.

[0022] The particular orientation of the first and second sets of grooves depends at least in part on the shape and number of the grooves. For example, when the first and second sets of grooves consist of linear grooves, the first and second sets of grooves are oriented such that the lines are non-parallel (e.g., skew). Typically, the first and second sets of grooves are oriented such that the first set of grooves is rotated by an angle of about 10° to about 90° relative to the second set of grooves when viewed by facing the top or bottom surface (i.e., with a line of sight perpendicular to the top and bottom surface). Preferably, the first set of grooves is rotated by an angle of about 45° to about 90° (e.g., about 60° to about 90°) relative to the second set of grooves. Such a polishing pad is depicted in FIGS. 1A and 1B. The polishing pad has a top surface (10) comprising a first set of grooves (12) and a bottom surface (14) comprising a second set of grooves (16), wherein the first set of grooves (12) are rotated by an angle of about 90° relative to the second set of grooves (16). When the first and second sets of grooves are curved grooves, the first and second sets of grooves preferably are oriented in different directions. For example, the first set of grooves can be rotated by an angle of about 10° to about 180° (e.g., about 90°, about 120°, or about 180°) relative to the second set of grooves. Such a polishing pad comprising a first set of curved grooves (12) that is rotated about 45° relative to a second set of curved grooves (16) is depicted in FIG. 2.

[0023] When the first and second sets of grooves each comprise grooves having the cross-sectional shape of circles, ovals, squares, rectangles, or triangles, the grooves can be oriented such that the first set of grooves is laterally displaced from the second set of grooves by a suitable distance. For example, the second set of grooves can be displaced from the first set of grooves by a distance that is about 10% or more (e.g., about 20% or more, or about 40% or more) of the distance between the symmetry axes of the individual grooves. Alternatively, the first set of grooves can be rotated by an angle of about 10° to about 180° (e.g., about 90°, about 120°, or about 180°) relative to the second set of grooves. FIG. 3 depicts a polishing pad comprising a first set of circular grooves (12) and a second set of circular grooves (16), wherein the first of circular grooves is displaced from the second set of circular grooves by a distance that is about 50% the distance between the axes of symmetry of the individual grooves.

[0024] The grooves can have any suitable width. The widths for each groove within the first or second groove set can be the same or different. Typically, the groove width will be about 0.1 mm to about 2 mm. The groove width can vary from groove to groove across the surface of the polishing pad. The average of the widths for the first set of grooves is defined as the first groove width. Similarly, the average of the widths for the second set of grooves is defined as the second groove width. The first and second groove widths can be the same or different.

[0025] The grooves can have any suitable depth. The depths for each groove within the first or second groove set can be the same or different. The average of the depths for the first set of grooves is defined as the first groove depth. Similarly, the average of the depths for the second set of grooves is defined as the second groove depth. The first and second groove depths can be the same or different. For example, the first groove depth can be larger than the second groove depth, or the second groove depth can be larger than the first groove depth.

[0026] The sum of the first and second groove depth gives the total groove depth. In one embodiment, the total groove depth is about equal to or greater than the total thickness of the polishing pad (i.e., the total distance from the top surface to the bottom surface of the polishing pad). For example, the first groove depth and second groove depth can each be about equal to one half the thickness of the polishing pad. Alternatively, the first groove depth can be about 55% or more (e.g., about 60% or more, or about 65% or more) of the thickness of the polishing pad while the second groove depth is 45% or less (e.g., about 40% or less, or about 35% or less) of the thickness of the polishing pad. In another embodiment, the total groove depth is less than the total thickness of the polishing pad. For example, the total groove depth can be about 90% or more (or even about 80% or more, about 70% or more, or about 60% or more) of the total thickness of the polishing pad.

[0027] Preferably, the total groove depth is about equal to or greater than the total thickness of the polishing pad. When the total groove depth is equal to or greater than the thickness of the polishing pad, the first and second sets of grooves will be interconnected by primary channels that are oriented perpendicular to the top and bottom surfaces of the polishing pad. The dimensions of these primary channels are defined by the widths of the first and second groove sets. The primary channels allow electrolyte to flow through the body of the polishing pad. Such primary channels (20) are shown in FIGS. 1A, 1B, 2, and 3.

[0028] If the total groove depth is less than the total thickness of the polishing pad, such that primary channels are not formed upon grooving of the top and bottom surface of the polishing pad, the first and second sets of grooves can be interconnected by secondary channels to facilitate flow of the electrolyte through the thickness of the polishing pad. Like the primary channels, the secondary channels extend from the top surface to the bottom surface of the polishing pad and are oriented perpendicular to the top and bottom surfaces. The secondary channels can have any suitable cross-sectional shape (e.g., circles, ovals, squares, triangles, diamonds, and the like) and any suitable dimension. The diameter of the secondary channels can be any suitable diameter. For example, the diameter of the secondary channels can be the same as or different from the diameter of the primary channels. The secondary channels can be placed at any suitable position across the polishing pad. For example, the secondary channels can be placed within a groove or outside of a groove (e.g., between grooves). The number and size of secondary channels will depend, at least in part, on the type of substrate being polishing. A polishing pad of the invention comprising a first set of grooves (12), a second set of grooves (16), and a plurality of secondary channels (22) that are positioned at the intersection of the first and second set of grooves is depicted in FIG. 4.

[0029] Of course, secondary channels can be used in combination with primary channels. In a preferred embodiment, both the first and second sets of grooves comprise linear grooves having a total groove depth equal to or greater than the thickness of the polishing pad such that the grooves are interconnected by primary channels, wherein the sets of grooves are oriented to form an angle of about 90°. FIGS. 5A and 5B depict another preferred polishing pad comprising a top surface (10) comprising a first set of grooves (12) and a bottom surface (14) comprising a second set of grooves (16), wherein the intersection of the first and second set of grooves produces primary channels (20) and the polishing pad further comprises a plurality of secondary channels (22).

[0030] Desirably, the polishing pad has a high void volume so as to maximize flow of the electrolyte through the polishing pad. For example, the void volume can be about 30% or more (e.g., about 50% or more, about 70% or more, or even about 80% or more). Typically, the void volume of the polishing pad will be about 95% or less (e.g., about 90% or less). The void volume of the polishing pad is made up by the first and second sets of grooves, the primary and secondary channels, and any void spaces (i.e., pores) within the body of the polishing pad. The void volume of the void spaces within the body of the polishing pad can be greater than, equal to, or less than the void volume of the grooves. Preferably, the body of the polishing pad comprises an open-cell pore structure that is capable of absorbing and transporting electrolyte.

[0031] Preferably, the number, width, depth, and orientation of the first and second sets of grooves are optimized to produce a uniform flow of electrolyte throughout each of the x, y, and z directions of the polishing pad. The flow of electrolyte through the polishing pad can be aided by a pumping action of the polishing pad during polishing. For example, a porous polishing pad can absorb electrolyte during polishing and then release the electrolyte slurry under increased downforce pressure of the polishing tool. The pumping action will cause the flow of electrolyte through the polishing pad to vary periodically as a function of the rotational speed of the polishing pad (and anode) and/or substrate carrier. The number, width, depth, and orientation of the first and second sets of grooves can be optimized to maximize this resonance with the pumping action of the polishing apparatus. The flow of the electrolyte through the polishing pad also can be aided by the presence of gas bubbles in the electrolyte. The gas bubbles can comprise any suitable gas and preferably comprise air.

[0032] In one embodiment, the width and/or depth of the grooves, and hence the volume capacity of the grooves, gradually diminishes from one side of the polishing pad to the other (e.g., opposite) side of the polishing pad. FIG. 6 depicts a polishing pad of this embodiment having a first set of linear grooves (12) and a second set of linear grooves (16) that are oriented 90° with respect to the first set of grooves, wherein the widths of the first and second sets of grooves increase from one side of the polishing pad to the other thereby producing a groove volume gradient. A polishing pad having a gradient groove configuration is particularly desirable in an ECMP apparatus that employs one or more pumps to locally introduce the electrolyte onto the surface of the polishing pad. When electrolyte is locally introduced into a region of the polishing pad having smaller electrolyte capacity, the design of the polishing pad will constrict the flow of the electrolyte and force the electrolyte to flow into other regions of the polishing pad before exiting the polishing pad. In the absence of such pad resistance, the electrolyte may only flow through a small region of the polishing pad. The uniformity of the electrolyte flow through the polishing pad is important to achieving uniformity of substrate removal.

[0033] The first and second sets of grooves can be angled. The angle of the groove can be any suitable angle, for example the groove angle can be about 75°, about 60°, about 45°, or about 30° relative to the plane of the polishing pad. The angles of the first and second sets of grooves desirably are such that the electrolyte flow is directed throughout the polishing pad. Preferably, the first and second sets of grooves have opposite angles such that the primary channels (if present) do not extend straight through the body of the polishing pad, but rather have a bend that could act to restrict flow of electrolyte.

[0034] The body of the polishing pad of the invention can comprise any suitable material. Typically, the body of the polishing pad comprises a polymer resin. Preferably, the polymer resin is selected from the group consisting of thermoplastic elastomers, thermoplastic polyurethanes, thermoplastic polyolefins, polycarbonates, polyvinylalcohols, nylons, elastomeric rubbers, elastomeric polyethylenes, polytetrafluoroethylenes, polyethyleneterephthalates, polyimides, polyaramides, polyarylenes, polyacrylates, polystyrenes, polymethylmethacrylates, copolymers thereof, and mixtures thereof. More preferably, the polymer resin is a thermoplastic polyurethane resin.

[0035] Because of the highly grooved nature of the polishing pad and accompanying high void volume, the type of polymer resin and physical properties of that polymer resin are important to maintaining the physical integrity of the polishing pad. The body of the polishing pad can be a solid material, a closed-cell material, or an open-cell material. The degree and type of porosity present in the polishing pad will depend, at least in part, on the type of substrate being polished.

[0036] In some embodiments, the body of the polishing pad is conductive. As such, the body of the polishing pad can comprise a conductive polymer or a nonconductive polymer comprising conductive elements that are embedded or formed therein. The conducting polymer can be any suitable conducting polymer. The conductive elements can be any suitable elements. For example, the conductive elements can consist of particles, fibers, wires, coils, or sheets that are evenly dispersed throughout the polymer resin. The conductive elements can comprise any suitable conductive material including carbon, conductive metals such as copper, platinum, platinum-coated copper, and aluminum, and the like. Examples of suitable conducting polishing pad elements are described in U.S. patent Application Publication No. 2002/0119286 A1.

[0037] The body of the polishing pad can comprise two or more polishing pad layers. For example, the first set of grooves may be contained within a first polishing pad layer while the second set of grooves is contained within a second polishing pad layer. The different polishing pad layers can have different chemical and physical properties. In some embodiments, it may be desirable that the first polishing pad layer be harder than the second polishing pad layer. The multiple pad layers can be joined together using adhesives or through welding or extrusion.

[0038] The polishing pad of the invention desirably is used in a method of polishing a substrate by ECMP. The method comprises (i) providing an ECMP apparatus comprising a polishing pad of the invention, (ii) providing a substrate to be polished, (iii) supplying the ECMP apparatus with an electrolytically conductive fluid, (iv) applying an electrochemical potential to a surface of the substrate, and (v) moving the polishing pad relative to the substrate to abrade the substrate and thereby polish the substrate. The electrochemical potential that is applied to the substrate can be fixed or can be varied over time, depending on the application.

[0039] The ECMP apparatus can be any suitable ECMP apparatus, many of which are known in the art. Typically, the ECMP apparatus comprises an ECMP station and a carrier assembly. The ECMP station preferably comprises an electrolyte chamber, a cathode, an anode, a reference electrode, a semi-permeable membrane, and a polishing pad of the invention. As shown in FIG. 7, the carrier assembly (36) is supported above the ECMP station. The cathode (32) preferably is disposed at the bottom of the electrolyte chamber (30) and is immersed in the electrolyte (42). The anode can be a conductive disk (34) upon which rests a polishing pad of the invention (40). Alternatively, the anode can be a conductive polishing pad of the invention. The cathode can have any suitable shape and dimension, and can comprise any suitable electrode material. Typically, the cathode is a non-consumable electrode comprising a material other than the deposited material that is to be removed by anodic dissolution. For example, the cathode can comprise platinum, copper, aluminum, gold, silver, tungsten, and the like. Preferably, the cathode comprises platinum. The reference electrode (44) can comprise any suitable electrode material and desirably is disposed within the electrolyte (42).

[0040] A semi-permeable membrane (38) desirably is disposed between the anodic disk (34) and the cathode (32). The semi-permeable membrane has a pore size that allows for the passage of electrolyte but exclude the passage of polishing debris and air bubbles (e.g., hydrogen bubbles) that evolve from the cathode during polishing. Preferably, the semi-permeable membrane is a glass frit having a pore size of about 5 to about 150 microns.

[0041] The electrolytically conductive fluid (i.e., electrolyte) typically comprises a liquid carrier and one or more electrolyte salts. The liquid carrier can be any suitable solvent and preferably comprises water, or is water. The electrolyte salt can be any suitable electrolyte salt and can be present in the liquid carrier in any suitable amount. Typically, the electrolyte salt is based on sulfuric acid, phosphoric acid, perchloric acid, or acetic acid. Suitable electrolyte salts include those selected from the group consisting of hydrogen sulfate, hydrogen chloride, hydrogen phosphate, potassium phosphate, and combinations thereof. Preferably, the electrolyte salt is potassium phosphate. The electrolyte can also comprise a base compound, for example potassium hydroxide. The electrolyte desirably has a concentration of about 0.2 M or more (e.g., about 0.5 M or more, or about 1.0 M or more). The electrolyte can have any suitable pH. Typically, the electrolyte has a pH of about 2 to about 11 (e.g., about 3 to about 10, or about 4 to about 9).

[0042] The electrolyte optionally comprises abrasive particles and polishing additives. The abrasive can be any suitable abrasive, and can be selected from the group consisting of silica, alumina, zirconia, titania, germania, magnesia, ceria, and combinations thereof. The polishing additives can be selected from the group consisting of corrosion inhibitors, film-forming agents, surfactants, and combinations thereof.

[0043] The polishing pad of the invention is suitable for use in a method of polishing many types of substrates (e.g., wafers) and substrate materials. For example, the polishing pads can be used to polish substrates including memory storage devices, glass substrates, memory or rigid disks, metals (e.g., noble metals), magnetic heads, inter-layer dielectric (ILD) layers, polymeric films, low and high dielectric constant films, ferroelectrics, micro-electro-mechanical systems (MEMS), semiconductor wafers, field emission displays, and other microelectronic substrates, especially substrates comprising insulating layers (e.g., metal oxide, silicon nitride, or low dielectric materials) and/or conductive material-containing layers (e.g., metal-containing layers). The term “memory or rigid disk” refers to any magnetic disk, hard disk, rigid disk, or memory disk for retaining information in electromagnetic form. Memory or rigid disks typically have a surface that comprises nickel-phosphorus, but the surface can comprise any other suitable material. Typically, the substrate comprises at least one conductive material. Suitable conductive materials include, for example, copper, tantalum, tungsten, aluminum, nickel, titanium, platinum, ruthenium, rhodium, iridium, alloys thereof, and mixtures thereof. The substrate also typically contains a metal oxide insulating layer. Suitable metal oxide insulating layers include, for example, alumina, silica, titania, ceria, zirconia, germania, magnesia, and combinations thereof. In addition, the substrate can comprise, consist essentially of, or consist of any suitable metal composite. Suitable metal composites include, for example, metal nitrides (e.g., tantalum nitride, titanium nitride, and tungsten nitride), metal carbides (e.g., silicon carbide and tungsten carbide), nickel-phosphorus, alumino-borosilicate, borosilicate glass, phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), silicon/germanium alloys, and silicon/germanium/carbon alloys. The substrate also can comprise, consist essentially of, or consist of any suitable semiconductor base material. Suitable semiconductor base materials include single-crystal silicon, poly-crystalline silicon, amorphous silicon, silicon-on-insulator, and gallium arsenide.

[0044] One of ordinary skill in the art will readily appreciate that the polishing pad of the invention can be used in other fabrication methods involving electrochemical activity or otherwise requiring a significant amount of flow of a polishing composition (e.g., liquid carrier and polishing additives) through the polishing pad. For example, the polishing pad of the invention can be used in electrochemical deposition and electrochemical mechanical plating processes (ECMPP), which include a combination of electrochemical deposition and chemical-mechanical polishing.

[0045] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0046] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0047] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
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US7153777 *Feb 20, 2004Dec 26, 2006Micron Technology, Inc.Methods and apparatuses for electrochemical-mechanical polishing
US7442116 *Nov 2, 2004Oct 28, 2008Jsr CorporationChemical mechanical polishing pad
US7503833Feb 8, 2007Mar 17, 2009Rohm And Haas Electronic Materials Cmp Holdings, Inc.Three-dimensional network for chemical mechanical polishing
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US7635291Jul 16, 2009Dec 22, 2009Rohm And Haas Electronic Materials Cmp Holdings, Inc.Interpenetrating network for chemical mechanical polishing
US7771251 *Oct 10, 2008Aug 10, 2010Rohm And Haas ElectronicThree-dimensional network for chemical mechanical polishing
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US7828634Aug 16, 2007Nov 9, 2010Rohm And Haas Electronic Materials Cmp Holdings, Inc.Interconnected-multi-element-lattice polishing pad
US7867066 *Dec 19, 2005Jan 11, 2011Toho Engineering Kabushiki KaishaPolishing pad
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Classifications
U.S. Classification451/41
International ClassificationB24B37/04, B24D13/14, B23H5/08
Cooperative ClassificationB23H5/08, B24B37/26, B24B37/046
European ClassificationB24B37/26, B24B37/04D, B23H5/08
Legal Events
DateCodeEventDescription
Jul 25, 2003ASAssignment
Owner name: CABOT MICROELECTRONICS CORPORATION, ILLINOIS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SEVILLA, ROLAND K.;REEL/FRAME:013831/0710
Effective date: 20030620