Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
  • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
  • H01L21/321—After treatment
  • H01L21/32115—Planarisation
  • H01L21/3212—Planarisation by chemical mechanical polishing [CMP]
• • 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
  • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
  • B24B37/042—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor
  • B24B37/044—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor characterised by the composition of the lapping agent
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09G—POLISHING COMPOSITIONS; SKI WAXES
  • C09G1/00—Polishing compositions
  • C09G1/02—Polishing compositions containing abrasives or grinding agents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K3/00—Materials not provided for elsewhere
  • C09K3/14—Anti-slip materials; Abrasives
  • C09K3/1454—Abrasive powders, suspensions and pastes for polishing
  • C09K3/1463—Aqueous liquid suspensions
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F3/00—Brightening metals by chemical means
  • C23F3/04—Heavy metals

Definitions

• This invention relates to polishing compositions and methods for polishing a substrate using the same. More particularly, this invention relates to chemical-mechanical polishing (CMP) compositions for polishing ruthenium-containing substrates.
• CMP chemical-mechanical polishing
• Semiconductor wafers typically have a complex structure composed of a substrate on which a plurality of transistors has been formed. Integrated circuits are chemically and physically connected into a substrate by patterning regions in the substrate and layers on the substrate with various materials including metals, insulators, and semiconductors. In order to produce an operable semiconductor wafer and to maximize the yield, performance, and reliability of the wafer, it is desirable to polish selected surfaces of the wafer (e.g., a metal- containing surface) without adversely affecting underlying structures or topography. This complexity leads to difficulties in designing effective polishing systems for semiconductor wafers. In fact, various problems in semiconductor fabrication can occur if the process steps are not performed on wafer surfaces that are adequately flat and uniform (planarized).
• polishing compositions and polishing pads can have less than desirable polishing rates, and their use in the chemical-mechanical polishing (CMP) of semiconductor surfaces can result in poor surface quality. This is particularly true for noble metals such as ruthenium, which is utilized in fabricating high performance semiconductor devices and capacitors in dynamic random access memory (DRAM) devices.
• DRAM dynamic random access memory
• ruthenium polishing compositions typically rely on relatively hard abrasives such as oalumina, and strong oxidizing agents, such as oxone or eerie ammonium nitrate, to provide adequate ruthenium removal rates (e.g., at least 100 Angstroms-per-minute (A/min) Ru removal rate). This is due, at least in part, to the high degree of chemical inertness and strong response to mechanical abrasion exhibited by ruthenium barrier layers.
• relatively weak oxidants such as hydrogen peroxide are not very efficient in ruthenium polishing processes, requiring long polishing times and a high polishing pressure in order to adequately planarize the ruthenium.
• ruthenium CMP compositions that utilize strong oxidants, such as oxone or eerie ammonium nitrate, work by oxidizing the ruthenium to relatively high oxidation state ruthenium species, such as toxic and undesirable ruthenium(VIII) tetroxide (RuO 4) , and concomitantly dissolving the oxidized ruthenium species from the surface of the substrate, aided by the hard abrasive (e.g., ⁇ -alumina).
• strong oxidants such as oxone or eerie ammonium nitrate
• ruthenium removal rates e.g., ⁇ 100 A/min
• uniform CMP of patterned wafers can be difficult to achieve, due to the harsh conditions typically required for ruthenium removal, which can result in over-removal of other materials, such as silicon dioxide (e.g., plasma enhanced tetraethylorthosilicate-derived silicon dioxide, PETEOS), resulting in poor surface quality.
• silicon dioxide e.g., plasma enhanced tetraethylorthosilicate-derived silicon dioxide, PETEOS
• polishing compositions also known as polishing slurries, CMP slurries, and CMP compositions
• polishing compositions typically contain an abrasive material in an aqueous carrier.
• a surface of a substrate is abraded to polish the surface by urging the surface of the substrate into contact with the polishing pad at a selected force (down force) and moving the polishing pad relative to the surface while maintaining a CMP slurry and oxidizing agent between the pad and the surface of the substrate.
• Typical abrasive materials include silicon dioxide (silica), cerium oxide (ceria), aluminum oxide (alumina), zirconium oxide (zirconia), titanium dioxide (titania), and tin oxide.
• U.S. Pat. No. 5,527,423 to Neville et al describes a method for chemically-mechanically polishing a metal layer by contacting the surface with a polishing slurry comprising high purity fine metal oxide particles in an aqueous medium. Alternatively, the abrasive material may be incorporated into the polishing pad.
• U.S. Pat. No. 5,489,233 to Cook et al discloses the use of polishing pads having a surface texture or pattern
• U.S. Pat. No. 5,958,794 to Bruxvoort et al. discloses a fixed abrasive polishing pad.
• a substrate carrier or polishing head is mounted on a carrier assembly and positioned in contact with a polishing pad in a CMP apparatus.
• the substrate is mounted on the polishing head.
• the carrier assembly provides a controllable pressure (down force) to urge the substrate against the polishing pad.
• the pad is moved relative to the substrate by an external driving force.
• the relative movement of the substrate and pad serves to abrade the surface of the substrate to remove a portion of the material from the substrate surface, thereby polishing the substrate.
• the polishing of the substrate by the relative movement of the pad and the substrate typically is further aided by the chemical activity of the polishing composition and/or the mechanical activity of an abrasive suspended in the polishing composition. It is highly desirable to utilize polishing compositions that are compatible with CMP apparatus as described herein.
• Ru CMP compositions to provide relatively high silicon dioxide removal rates (e.g., at least 100 A/min, preferably 200 A/min or greater for removal of PETEOS), in addition to relatively high Ru removal rates and low defectivity.
• the present invention provides a CMP composition useful for polishing a ruthenium-containing substrate in the presence of an oxidizing agent such as hydrogen peroxide without generating toxic levels OfRuO 4 .
• the compositions of the invention comprise a particulate abrasive suspended in an aqueous carrier containing a ruthenium-coordinating oxidized nitrogen ligand (N-O ligand), such as a nitroso compound, a nitroxide, an imino nitroxide, a nitronyl nitroxide, an oxime, a hydroxamic acid, and the like.
• N-O ligand ruthenium-coordinating oxidized nitrogen ligand
• the N-O ligand prevents deposition of relatively high oxidation state ruthenium species (i.e., Ru(IV) or higher) on the surface of the substrate and concomitantly forms a soluble Ru(II) N-O coordination complex to aid in removal of ruthenium from the surface of the substrate.
• ruthenium species i.e., Ru(IV) or higher
• the combined chemical activity of the oxidizing agent and the N-O ligand allows for the use of relatively soft abrasive materials, such as titania and colloidal silica, if desired.
• the compositions of the invention comprise 1 to 10 percent by weight of the particulate abrasive (e.g., silica, titania, or alumina), and 0.01 to 0.5 percent by weight of the N-O ligand.
• the composition preferably is combined with the oxidizing agent at a concentration of oxidizing agent in the range of 1 to 5 percent by weight, based on the combined weight of the composition and the oxidizing agent.
• the compositions of the invention utilize alumina or titania as the particulate abrasive. In other preferred embodiments, the compositions of the invention utilize colloidal silica or a combination of colloidal silica and titania as the abrasive. [0012] In some preferred embodiments, the compositions of the invention include a nitroxide compound and ascorbic acid, preferably in a 1:1 molar ratio of ascorbic acid-to- nitroxide compound.
• compositions of the present invention desirably can be tailored to provide a ruthenium-to-silicon dioxide removal selectivity, which favors either ruthenium removal or silicon dioxide removal, as may be needed for a given polishing application.
• the compositions of the invention provide a ruthenium-to-silicon oxide removal selectivity that favors ruthenium removal, and provide a relatively high ruthenium removal rate of at least 100 A/min, preferably 200 A/min or greater, when utilized in typical CMP processes.
• the compositions of the invention provide a ruthenium-to-silicon oxide removal selectivity that favors silicon dioxide (e.g., PETEOS) removal, while still providing adequate ruthenium removal rates.
• the present invention provides CMP methods for polishing a ruthenium-containing substrate.
• Preferred methods comprise the steps of contacting a surface of the substrate (e.g., a ruthenium-containing substrate) with a polishing pad and an aqueous CMP composition of the present invention, in the presence of an oxidizing agent such as hydrogen peroxide, and causing relative motion between the polishing pad and the substrate while maintaining at least a portion of the CMP composition and the oxidizing agent in contact with the surface between the pad and the substrate for a time period sufficient to abrade at least a portion of the ruthenium from the surface of the substrate.
• an oxidizing agent such as hydrogen peroxide
• the present invention provides a method of selectively removing ruthenium from the surface of the substrate in preference to removal of silicon dioxide (e.g., PETEOS).
• the abrasive can be either alumina or titania.
• the present invention provides a method of selectively removing silicon dioxide (e.g., PETEOS) from the surface of the substrate in preference to removal of ruthenium.
• the abrasive comprises colloidal silica.
• the abrasive includes titania and colloidal silica.
• FIG. 1 presents a bar graph of ruthenium and PETEOS removal rates obtained with compositions of the invention containing titania and alumina abrasives, compared to a conventional alumina- and titania-based CMP composition.
• FIG. 2 shows a bar graph of ruthenium and PETEOS removal rates obtained with compositions of the invention containing an alumina abrasive, compared to a conventional alumina-based CMP composition.
• FIG. 3 shows a bar graph of ruthenium and PETEOS removal rates obtained with compositions of the invention containing a colloidal silica-containing abrasive, or a mixed silica/titania abrasive, compared to conventional silica-based and alumina-based CMP compositions.
• the present invention provides a CMP composition for polishing a ruthenium- containing substrate in the presence of an oxidizing agent such as hydrogen peroxide, an organic peroxide, an organic hydroperoxide, a periodate, a perborate, and the like, without forming a toxic level of ruthenium tetroxide during the polishing process.
• the composition comprises a particulate abrasive suspended in an aqueous carrier containing a ruthenium- coordinating oxidized nitrogen ligand (N-O ligand).
• the N-O ligand is capable of preventing the deposition of ruthenium species having an oxidation state of rV or higher on the surface of the substrate, and concomitantly is capable of forming soluble Ru(II) N-O coordination complexes with oxidized ruthenium formed during CMP of the substrate. It is believed that the N-O ligand reduces relatively high oxidation state ruthenium (i.e., Ru(IV) and higher) to Ru(II), and then forms a soluble complex with the so- formed Ru(II) species. The Ru(II) complex is believed to involve coordination with both the N and the O atoms of the ligand.
• a preferred CMP composition of the invention comprises 1 to 10 percent by weight of a particulate abrasive suspended in an aqueous carrier containing 0.01 to 0.5 percent by weight of an N-O ligand, preferably a nitroxide compound.
• oxidized nitrogen ligand and "N-O-ligand” refer to organic compounds containing a nitrogen-based functional group bearing an oxygen atom or other oxygen functional group (e.g., a hydroxyl group), which either directly coordinates with oxidized ruthenium, e.g., Ru(II), or which forms such a coordinating ligand in situ (e.g., by reaction with hydrogen peroxide).
• N-O ligands include nitroxides, imino nitroxides, nitronyl nitroxides, oximes, hydroxamic acids, and the like.
• Non-limiting examples of nitroxides include 2,2,6,6-tetramethylpiperidine-l-oxyl (TEMPO), 4-hydroxy- TEMPO, and the like.
• Non-limiting examples of imino nitroxides include 2-pyridyl-4,4,5,5- tetramethyl- 1 ,3-diazacyclopent-2-ene- 1 -oxyl, 4-hydrazonomethyl- 1 -hydroxy-2 ,2,5,5 - tetramethyl-3-imidazoline-3 -oxide, and the like.
• Non-limiting examples of suitable nitronyl nitroxides include 2-pyridyl-4,4,5,5-tetramethyl-l,3-diazacyclopent-2-ene-l-oxyl-3-oxide, and the like.
• Non-limiting examples of oximes include pinacolone oxime, progesterone 3-(O- carboxymethyl) oxime, propionaldehyde O-pentafluorophenylmethyl-oxime, (E)-benzaldehyde oxime, l,2-indandione-2-oxime, 1-indanone oxime, 2,2,4,4-tetramethyl-3-pentanone oxime, 2- adamantanone oxime, 2-butanone oxime, 2-chlorobenzaldehyde oxime, and the like.
• Non- limiting, examples of hydroxamic acids include acetylhydroxamic acid, salicylhydroxamic acid, and the like.
• the compositions of the invention the N-O ligand comprises a nitroxide compound such as 4-hydroxy-TEMPO.
• the N- O ligand preferably is present in the compositions of the invention at a concentration in the range of 0.01 to 0.5 percent by weight.
• the CMP compositions of the invention are utilized to polish ruthenium substrates in the presence of an oxidizing agent such as hydrogen peroxide.
• an oxidizing agent such as hydrogen peroxide.
• the oxidizing agent is present at a concentration in the range of 1 to 5 percent by weight during the CMP process.
• the oxidizing agent preferably is added to the CMP composition just prior to initiation of the CMP process.
• oxidizers include, without limitation, perborates, periodates, organic peroxides and hydroperoxides, (e.g., di-tert-butyl peroxide, di-tert-amyl peroxide, benzoyl peroxide, tert-butyl-hydroperoxide, and tert-amyl-hydroperoxide), and the like.
• the CMP compositions of the invention also include a particulate abrasive.
• the abrasive can be any abrasive material suitable for use in CMP processes, such as silica, alumina, titania, zirconia, ceria, doped silica, and combinations thereof.
• the abrasive comprises alumina, titanium dioxide, silica (e.g., colloidal silica or fumed silica), or a combination of two or more of these abrasives. In some embodiments, a combination of titania and colloidal silica is preferred.
• the particulate abrasive preferably has a mean particle size in the range of 30 to 200 nm, e.g., as determined by laser light scattering techniques.
• the particulate abrasive is present in the composition at a concentration in the range of 1 to 10 percent by weight.
• the abrasive desirably is suspended in the CMP composition, more specifically in the aqueous component of the CMP composition.
• the abrasive preferably is colloidally stable.
• colloid refers to the suspension of abrasive particles in the liquid carrier.
• Colloidal stability refers to the maintenance of that suspension over time.
• a suspension of a particulate abrasive is considered colloidally stable if, when the suspension is placed into a 100 mL graduated cylinder and allowed to stand without agitation for a time of 2 hours, the difference between the concentration of abrasive particles suspended in the bottom 50 mL of the graduated cylinder ([B] in terms of g/mL) and the concentration of abrasive particles suspended in the top 50 mL of the graduated cylinder ([T] in terms of g/mL) divided by the initial concentration of particles in the abrasive composition ([C] in terms of g/mL) is less than or equal to 0.5 (i.e., ([B] - [T])Z[C] ⁇ 0.5).
• the value of ([B]-[T])Z[C] desirably is less than or equal to 0.3, and preferably is less than or equal to 0.1.
• the CMP compositions of the invention can have any pH that is compatible with the redox chemistry involved in the oxidation of ruthenium by the oxidizing agent, and is compatible with the formation of Ru(II) N-O ligand complexes.
• the pH of the compositions is in the range of 2 to 10.
• the aqueous carrier can be any aqueous liquid suitable for use in a CMP process.
• Such compositions include water, aqueous alcohol solutions, and the like.
• the aqueous carrier comprises deionized water.
• the CMP compositions of the invention optionally can comprise one or more additives, such as a surfactant, a rheological control agent (e.g., a viscosity enhancing agent or coagulant), a corrosion inhibitor (e.g., benzotriazole (BTA) or 1,2,4-triazole (TAZ)), a dispersant, a biocide, and the like.
• a surfactant e.g., a viscosity enhancing agent or coagulant
• a corrosion inhibitor e.g., benzotriazole (BTA) or 1,2,4-triazole (TAZ)
• a dispersant e.g., benzotriazole (BTA) or 1,2,4-triazole (TAZ)
• a dispersant e.g., benzotriazole (BTA) or 1,2,4-triazole (TAZ)
• a dispersant e.g., benzotriazole (BTA) or 1,2,
• ascorbic acid When ascorbic acid is present in the CMP composition, it forms a charge-transfer complex with the surface of the abrasive (e.g., titania), which can generates a higher energy oxidant, such as superoxide radical anion, which is a more efficient oxidant for Ru compared to hydrogen peroxide.
• abrasive e.g., titania
• the CMP compositions of the invention can be prepared by any suitable technique, many of which are known to those skilled in the art.
• the CMP composition can be prepared in a batch or continuous process.
• the CMP composition can be prepared by combining the components thereof in any order.
• component as used herein includes individual ingredients (e.g., abrasive, N-O ligand, acids, bases, and the like) as well as any combination of ingredients.
• the N-O ligand can be dissolved in water, the abrasive can be dispersed in the resulting solution, and any additional additive materials such as rheological control agents, buffers, and the like can then be added and mixed by any method that is capable of uniformly incorporating the components into the CMP composition.
• the pH can be adjusted at any suitable time, if needed.
• the oxidizing agent e.g., hydrogen peroxide, can be added just prior to, and/or during, the CMP process.
• the CMP compositions of the present invention also can be provided as a concentrate, which is intended to be diluted with an appropriate amount of aqueous carrier prior to use.
• the CMP composition concentrate can comprise an abrasive, a N-O ligand compound, and any other components dispersed or dissolved in an aqueous carrier in amounts such that, upon dilution of the concentrate with an appropriate amount of aqueous carrier (e.g., water), each component of the polishing composition will be present in the CMP composition in an amount within the appropriate range for use.
• aqueous carrier e.g., water
• the present invention also provides methods of polishing a ruthenium-containing substrate, which comprises abrading the surface of the substrate with a CMP composition of the invention, as described herein, in the presence of an oxidizing agent such as hydrogen peroxide (e.g., 1 to 5 percent by weight hydrogen peroxide).
• an oxidizing agent such as hydrogen peroxide (e.g., 1 to 5 percent by weight hydrogen peroxide).
• the present invention provides a CMP method for selectively removing ruthenium from the surface of a substrate in preference to silicon dioxide.
• the method comprises (a) contacting a surface of a substrate with a polishing pad and an aqueous CMP composition of the invention, as described herein, in the presence of an oxidizing agent such as hydrogen peroxide; and (b) causing relative motion between the polishing pad and the substrate while maintaining a portion of the CMP composition and the oxidizing agent in contact with the surface between the pad and the substrate for a time period sufficient to abrade at least some ruthenium from the surface.
• the particulate abrasive comprises alumina, titania, or a combination thereof.
• the invention provides a CMP method for selectively removing silicon dioxide from the surface of a substrate in preference to ruthenium.
• the method comprises (a) contacting a surface of a substrate with a polishing pad and an aqueous CMP composition of the invention in the presence of an oxidizing agent such as hydrogen peroxide; and (b) causing relative motion between the polishing pad and the substrate while maintaining a portion of the CMP composition and oxidizing agent in contact with the surface between the pad and the substrate for a time period sufficient to abrade at least a portion ruthenium present in the substrate from the surface.
• the particulate abrasive comprises colloidal silica or a combination of colloidal silica and titania.
• a combination of colloidal silica and titania is particularly preferred, in which, the titania preferably is present in a weight ratio of silica-to-titania in the range of 60: 1 to 6: 1.
• the CMP methods of the present invention can be used to polish any suitable substrate, and are especially useful for polishing semiconductor substrates comprising ruthenium.
• suitable substrates include, without limitation, wafers used in the semiconductor industry.
• the CMP methods of the present invention are particularly suited for use in conjunction with a chemical-mechanical polishing apparatus.
• the CMP apparatus comprises a platen, which, when in use, is in motion and has a velocity that results from orbital, linear, or circular motion, a polishing pad in contact with the platen and moving with the platen when in motion, and a carrier that holds a substrate to be polished by contacting and moving the substrate relative to the surface of the polishing pad.
• a CMP composition of the invention and an oxidizing agent such as hydrogen peroxide are deposited onto the polishing pad, so that some the CMP composition and oxidizing agent are disposed between the pad and the substrate.
• the polishing of the substrate takes place by the combined chemical and mechanical action of the polishing pad, the CMP composition of the invention, and the oxidizing agent, which act together to oxidize and abrade the substrate surface.
• a substrate can be planarized or polished with a CMP composition of the invention using any suitable polishing pad (e.g., polishing surface).
• suitable polishing pads include, for example, woven and non-woven polishing pads.
• suitable polishing pads can comprise any suitable polymer of varying density, hardness, thickness, compressibility, ability to rebound upon compression, and compression modulus.
• Suitable polymers include, for example, polyvinylchloride, polyvinylfluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, coformed products thereof, and mixtures thereof.
• the CMP apparatus further comprises an in situ polishing endpoint detection system, many of which are known in the art.
• Techniques for inspecting and monitoring the polishing process by analyzing light or other radiation reflected from a surface of the workpiece are known in the art. Such methods are described, for example, in U.S. Patent 5,196,353 to Sandhu et al., U.S. Patent 5,433,651 to Lustig et al., U.S. Patent 5,949,927 to Tang, and U.S. Patent 5,964,643 to Birang et al.
• the inspection or monitoring of the progress of the polishing process with respect to a workpiece being polished enables the determination of the polishing end-point, i.e., the determination of when to terminate the polishing process with respect to a particular workpiece.
• compositions of the invention comprising a titania abrasive and 4-hydroxy-TEMPO ("4-HOT") to polish ruthenium and PETEOS blanket wafers.
• 4-HOT 4-hydroxy-TEMPO
• CMP compositions of the invention were prepared, which had the formulations shown in Table 1.
• the compositions were utilized to polish ruthenium and PETEOS blanket wafers (4-inch diameter) in the presence of 1 percent by weight hydrogen peroxide, on a Logitech polisher having a DlOO polishing pad, under the following polishing conditions: platen speed of 93 revolutions-per-minute (rpm), carrier speed of 90 rpm, down pressure of 3.1 pounds-per-square inch (psi), and a slurry flow rate of 180 milliliters-per-minute (mL/min).
• FIG. 1 provides a graph of the ruthenium and PETEOS removal rates observed for each composition, in comparison to control compositions comprising 0.7 percent by weight alumina or 1 percent by weight titania, and having no added N-O ligand.
• Control IB 1 wt. % of a pH 9.5 aqueous dispersion of titanium dioxide (120 nm Control mean particle size) ⁇ final pH of 9.5
• compositions of the invention including a titania abrasive provided significant and unexpected increases in the ruthenium removal rates compared to the conventional titania control slurry (control compositions (IB and 1C), as well as a conventional alumina control slurry (IA).
• the compositions of the invention provided a significant increase in PETEOS removal rates compared to the controls.
• the compositions of the invention surprisingly provided a significantly greater selectivity for ruthenium removal versus silicon dioxide removal, compared to the control compositions.
• compositions of the invention comprising an alumina abrasive and 4-hydroxy-TEMPO to polish ruthenium and PETEOS blanket wafers.
• CMP compositions of the invention were prepared, each of which had a pH of 8.5 , and the formulations shown in Table 2. The compositions were utilized to polish ruthenium and PETEOS blanket wafers (4-inch diameter) in the presence of 1 percent by weight hydrogen peroxide, on a Logitech polisher having a DlOO polishing pad, under the following polishing conditions: platen speed of 93 rpm, carrier speed of 90 rpm, down pressure of 3.1 psi, and a slurry flow rate of 180mL/min.
• FIG. 2 provides a graph of the ruthenium and PETEOS removal rates observed for each composition, in comparison to a control composition comprising 0.7 percent by weight alumina having no added N-O ligand.
• compositions of the invention (2B, 2C, 2D, and 2E) including an alumina abrasive provided significant and unexpected increases in the ruthenium removal rates compared to the conventional alumina control composition (IA), while not adversely affecting the PETEOS removal rates, thereby affording an unexpected increase in the ruthenium removal selectivity relative to silicon dioxide removal compared to the selectivity observed with the controls.
• EXAMPLE 3
• compositions of the invention comprising silica and mixed silica/titania abrasives in combination with 4-hydroxy-TEMPO to polish ruthenium and PETEOS blanket wafers.
• CMP compositions of the invention were prepared, which had the formulations shown in Table 3. Each composition had a pH of 5. The compositions were utilized to polish ruthenium and PETEOS blanket wafers (4-inch diameter) in the presence of 1 percent by weight hydrogen peroxide, on a Logitech polisher having a DlOO polishing pad, under the following polishing conditions: platen speed of 93 rpm, carrier speed of 90 rpm, down pressure of 3.1 psi, and a slurry flow rate of 180mL/min.
• 3 provides a graph of the ruthenium and PETEOS removal rates observed for each composition, in comparison to three control compositions having no added N-O ligand (i.e., 3 A: 0.7 percent by weight alumina (pH 8.5); 3B: 6 percent by weight colloidal silica (pH 5); and 3C: 6 percent by weight colloidal silica combined with 0.5 percent by weight titanium dioxide at pH 5).
• 3 A 0.7 percent by weight alumina (pH 8.5);
• 3B 6 percent by weight colloidal silica (pH 5);
• 3C 6 percent by weight colloidal silica combined with 0.5 percent by weight titanium dioxide at pH 5).
• Control dioxide 150 nm mean particle size
• compositions of the invention including a combination of silica and titania provided for selectivity of PETEOS removal over ruthenium removal, while maintaining a ruthenium removal rate of at least 100 A/min.
• composition 3E containing ascorbic acid, also increased the Ru removal rate by 80 percent, compared to control 3C.

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• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

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• 2007
  • 2007-08-01 US US11/888,406 patent/US8008202B2/en not_active Expired - Fee Related
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