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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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]
• • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
  • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
  • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
• • 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
  • C09K3/1409—Abrasive particles per se
• • 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
  • C23F3/06—Heavy metals with acidic solutions

Definitions

• This invention relates to chemical-mechanical planarization processes in general and more specifically to a molybdenum oxide slurry and method for the chemical-mechanical planarization of copper.
• CMP Chemical-mechanical planarization
• the CMP process is typically used in semiconductor processing to polish (e.g., planarize) the surface of the semiconductor wafer.
• the CMP process is relatively new in that, until recently, conventional processes were sufficient with the comparatively low circuit densities involved.
• increases in circuit densities e.g., the transition from wafers having 0.25 micron features to 0.18 micron features
• CMP chemical-mechanical planarization
• the chemical-mechanical planarization (CMP) process involves scrubbing a semiconductor wafer with a pad in the presence of a chemically reactive slurry that contains abrasive particles.
• CMP chemical-mechanical planarization
• the planarization action of the chemical-mechanical planarization (CMP) process is both chemical and mechanical. Chemicals aid in material removal by modifying the surface film while abrasion between the surface particles, pad, and the modified film facilitates mechanical removal. It is believed that this synergistic interplay between the chemical and mechanical components in the process is the key to the effective planarization of the CMP process.
• the claimed invention involves a novel aqueous planarization slurry for chemical-mechanical planarization that is effective for planarizing copper at high polish rates.
• the aqueous slurry according to the present invention comprises particles of MoO 3 dissolved in an oxidizing agent.
• Embodiments of aqueous slurries may contain dissolved MoO 3 in amounts ranging from about 0.1
• the oxidizing agent may comprise any one or a mixture of hydrogen peroxide (H 2 O 2 ), ferric nitrate (Fe(NO 3 ) 3 ), potassium iodate (KIO 3 ), nitric acid (HNO 3 ), potassium permanganate (KMn0 ), potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate ((NH 4 ) 2 S 2 0 8 ), potassium periodate (KIO ), and hydroxylamine (NH 2 OH). Additionally, complexing agents may be used in the molybdenum trioxide (M0O 3 ) aqueous slurry.
• M0O 3 molybdenum trioxide
• Complexing agents may comprise any one or a mixture of glycine (C 2 H 5 NO 2 ), alanine (C 3 H 7 N0 2 ), amino butyric acids (C 4 H 9 N0 2 ) ethylene diamine (C 2 H 8 N 2 ), ethylene diamine tetra acetic acid (EDTA), ammonia (NH 3 ), family of mono, di, and tri- carboxylic acids like citric acid (C 6 H 8 0 ), phthalic acid (C 6 H t (COOH) 2 ), oxalic acid (C 2 H 2 O ), acetic acid (C 2 H 1 O 2 ), succinic acid (C 4 H 6 O 4 ), and family of amino benzoic acids.
• glycine C 2 H 5 NO 2
• alanine C 3 H 7 N0 2
• amino butyric acids C 4 H 9 N0 2
• ethylene diamine C 2 H 8 N 2
• EDTA ethylene diamine tetra acetic acid
• Embodiments of slurries containing molybdenum trioxide (M0O 3 ) may also be provided with a nonionic surfactant, an anionic surfactant, or a cationic surfactant.
• the anionic surfactant in the aqueous slurry may comprise any one or a mixture of polyacrylic acid (PAA), a carboxylic acid or its salt, a sulfuric ester or its salt, a sulfonic acid or its salt, a phosphoric acid or its salt, and a sulfosuccinic acid or its salt.
• PAA polyacrylic acid
• the cationic surfactant in the aqueous slurry may comprise any one or a mixture of a primary amine or its salt, a secondary amine or its salt, a tertiary amine or its salt, and a quaternary amine or its salt.
• the nonionic surfactant may comprise any one or a mixture of one of many polyethylene glycols.
• Still yet other embodiments of aqueous slurries may be provided with a copper corrosion inhibitor which may comprise any one or a mixture of heterocyclic organic compounds including benzotriazole (BTA), benzimidazole, poly triazole, phenyl triazole, thion and their derivatives.
• slurries may contain any combination of these surfactants and corrosion inhibitors.
• Aqueous slurries may optionally include acids or bases for adjusting the pH within an effective range from about 1 to about 14.
• Yet additional embodiments of slurries according to the invention may also be provided with supplemental ceramic/metal oxide particles.
• Such supplemental ceramic/metal oxide particles used in the aqueous slurry may comprise any one or a mixture of silica, ceria, aluminia, zirconia, titania, magnesia, iron oxide, tin oxide, and germania.
• the present invention also includes a novel method of planarizing copper by chemical-mechanical planarization.
• the method of the present invention comprises planarizing copper using a polishing pad and an aqueous slurry comprising dissolved M0O 3 particles and an oxidizing agent.
• Embodiments of the method of planarizing copper using a slurry may contain M0O 3 in amounts ranging from about 0.1 % to about 10 % by weight of M0O3 and the oxidizing agent may comprise any one or a mixture of hydrogen peroxide (H 2 O 2 ), ferric nitrate (Fe(NO 3 ) 3 ), potassium iodate (KIO 3 ), nitric acid (HNO 3 ), potassium permanganate (KMn0 4 ), potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate ((NH 4 ) 2 S 2 0 8 ), potassium periodate (KIO 4 ), and hydroxylamine (NH 2 OH).
• complexing agents may be used in the molybdenum trioxide (M0O3) aqueous slurry.
• Complexing agents may comprise any one or a mixture of glycine (C 2 H 5 NO 2 ), alanine (C 3 H 7 NO 2 ), amino butyric acids (C 4 H 9 N0 2 ), ethylene diamine (C 2 H 8 N 2 ), ethylene diamine tetra acetic acid (EDTA), ammonia (NH 3 ), family of mono, di and tri carboxylic acids like citric acid (C ⁇ H 8 0 7 ), phthalic acid oxalic acid (C 2 H 2 0 4 ), acetic acid (C 2 H 4 O 2 ), and succinic acid (C 4 H 6 O 4 ) and family of amino benzoic acids.
• the anionic surfactant used in the aqueous slurry may comprise any one or a mixture of polyacrylic acid (PAA), a carboxylic acid or its salt, a sulfuric ester or its salt, a sulfonic acid or its salt, a phosphoric acid or its salt, and a sulfosuccinic acid or its salt.
• PAA polyacrylic acid
• the cationic surfactant used in the aqueous slurry may comprise any one or a mixture of a primary amine or its salt, a secondary amine or its salt, a tertiary amine or its salt, and a quaternary amine or its salt.
• the nonionic surfactant may comprise any one or a mixture of one of many polyethylene glycols.
• Still yet other embodiments of the method of planarizing copper using an aqueous slurry may be provided with a copper corrosion inhibitor which may comprise any one or a mixture of heterocyclic organic compounds including benzotriazole (BTA), benzimidazole, poly triazole, phenyl triazole, thion and their derivatives.
• BTA benzotriazole
• benzimidazole poly triazole
• phenyl triazole thion and their derivatives.
• slurries may contain any combination of these surfactants and corrosion inhibitors.
• Aqueous slurries may optionally include acids or bases for adjusting the pH within an effective range of from about 1 to about 14.
• Yet additional embodiments of slurries according to the invention may also be provided with supplemental ceramic/metal oxide particles.
• Such supplemental ceramic/metal oxide particles used in the aqueous slurry may comprise any one or a mixture of silica, ceria, zirconia, titania, magnesia, iron oxide, tin oxide, and germania. Brief Description of the Drawing The figure is a plot of the potentiodynamic polarization curves of copper and tantalum coupons in a slurry containing M0O 3 .
• embodiments of aqueous slurries according to the present invention may comprise a molybdenum oxide (MoO ) polishing material and an oxidizing agent.
• MoO polishing material may be present in an amount of about 0.5 to about 10 wt.%, such as about 1 to about 3 wt.%, and more preferably in an amount of about 3 wt.%.
• the molybdenum oxide polishing material may comprise fine particles of MoO 2 having a mean particle size in the range of about 25 nanometers (nm) to about 1 micron, such as about 25 nanometers to about 560 nm, and more preferably about 50 to 200 nm, as measured by a Horiba laser scattering analyzer.
• the Mo0 2 particles may be produced from a variety of molybdenum-containing precursor materials, such as, for example, ammonium molybdates and related compounds, as well as molybdenum oxides prepared from a variety of processes known in the art, wherein molybdenum precursors and products can be made into particles within the size ranges specified herein.
• Mo0 2 may be reduced in size to the ranges specified herein by any of a variety of milling methods known in the art, such as attrition milling assisted by the use of appropriate reagents.
• embodiments of slurries according to the present invention may utilize particles of Mo0 2 produced from a precursor material comprising nano-particles of M0O 3 . Nano-particles of MoO 3 are commercially available from the Climax Molybdenum Company of Ft. Madison, Iowa (US).
• nano-particles of M0O 3 may be produced in accordance with the teachings provided in U.S.
• Patent No. 6,468,497 Bl entitled “Method for Producing Nano-Particles of Molybdenum Oxide,” which is hereby incorporated herein by reference for all that it discloses. Regardless of whether the nano-particles of M0O 3 are obtained commercially or manufactured in accordance with the teachings provided in U.S. Patent No. 6,468,497 Bl, identified above, the MoO 2 particles comprising the polishing material may be produced by heating nano-particles of M0O 3 for a time sufficient to convert substantially all of the M0O3 to MoO 2 .
• the nano-particles of M0O 3 may be heated in a reducing atmosphere (e.g., hydrogen) to a temperature in the range of about 400°C to about 700°C (550°C preferred). Times may be in the range of about 30 to about 180 minutes, as may be required to reduce M0O 3 to MoO 2 in sufficient quantities. Heating may be accomplished in a rotary furnace, although other types of furnaces may be used. If necessary, the resulting M0O 2 product may then be ground to produce an MoO 2 polishing material having a mean particle diameter within the ranges specified herein. A particle classification step may optionally be used to ensure that the resulting MoO 2 polishing material lacks particles that may cause damage during polishing.
• a reducing atmosphere e.g., hydrogen
• the oxidizing agent may comprise any one or a mixture of ferric nitrate (Fe(NO 3 ) 3 ), nitric acid (HNO 3 ), potassium iodide (KI), and potassium iodate (KIO 3 ).
• Ferric nitrate oxidizing agent may be present in concentrations ranging from about 0.05 to about 0.2 molar (M) Fe(NO 3 ) 3 , such as about 0.1 to about 0.2M Fe(NO 3 ) 3 , and more preferably in a concentration of about 0.2 M Fe(NO 3 ) 3 .
• Nitric acid oxidizing agent may be present in amounts ranging from about 0.5 to about 2 wt.% HNO 3 , such as about 1 to about 2 wt.%) HNO 3 , and more preferably in an amount of about 2 wt.% HN0 3 .
• Potassium iodide oxidizing agent may be present in amounts ranging from about 0.5 to about 5 wt.% KI, such as about 1 to about 5 wt.% KI, and more preferably in an amount of about 3 wt.% KI.
• Potassium iodate oxidizing agent may be present in amounts ranging from about 1 to about 5 wt. % KIO 3 , such as about 1 to about 3 wt.
• Additional oxidizing agents may comprise any one or a mixture of hydroxylamine hydrochloride ((NH 2 OH)Cl) and potassium permanganate (KMn0 4 ). Hydroxylamine hydrochloride oxidizing agent may be present in amounts ranging from about 1 to about 5 wt.% (NH 2 OH)Cl, such as about 2 to about 4 wt.%) (NH 2 OH)Cl, and more preferably in an amount of about 3 wt.% (NH 2 OH)Cl.
• Potassium permanganate oxidizing agent may be present in amounts ranging from about 1 to about 5 wt.% KMn0 4 , such as about 2 to about 4 wt.% KMn0 4 , and more preferably in an amount of about 3 wt.% KMn0 4 .
• polishing rates with slurries containing hydroxylamine hydrochloride and potassium permanganate are generally lower than with the other oxidizing agents identified herein.
• Embodiments of slurries according to the present invention may also be provided with an anionic surfactant or a cationic surfactant.
• the anionic surfactant used in the aqueous slurry may comprise any one or a mixture of polyacrylic acid (PAA), a carboxylic acid or its salt, a sulfuric ester or its salt, a sulfonic acid or its salt, a phosphoric acid or its salt, and a sulfosuccinic acid or its salt.
• PAA polyacrylic acid
• the cationic surfactant used in the aqueous slurry may comprise any one or a mixture of a primary amine or its salt, a secondary amine or its salt, a tertiary amine or its salt, and a quaternary amine or its salt.
• the aqueous slurry may be provided with a copper corrosion inhibitor which may comprise any one or a mixture of heterocyclic organic compounds including benzotriazole (BTA), triazole, and benzimidazole.
• a copper corrosion inhibitor which may comprise any one or a mixture of heterocyclic organic compounds including benzotriazole (BTA), triazole, and benzimidazole.
• the slurry may contain any combination of these surfactants and corrosion inhibitors.
• a preferred anionic surfactant is polyacrylic acid (PAA).
• a preferred cationic surfactant is cetyl pyridinium chloride (CPC).
• a preferred copper corrosion inhibitor is benzotriazole (BTA). The addition of PAA improved slurry dispersability and surface quality.
• PAA polyacrylic acid
• PAA surfactant may be present in amounts ranging from about 0.1 to about 4 wt.% PAA, such as about 0.5 to about 1 wt.% PAA, and more preferably in an amount of about 1 wt.% PAA.
• the cationic surfactant cetyl pyridinium chloride (CPC) may be present in amounts ranging from about 0.01 to about 1 wt.% CPC, such as about 0.05 to about 0.5 wt.% CPC, and more preferably in an amount of about 0.1 wt.% CPC.
• Benzotriazole (BTA) copper corrosion inhibitor may be present in concentrations ranging from about 0.5 to about 10 milli-molar (mM) BTA, such as about 1 to about 5 mM BTA, and more preferably in a concentration of about 1 mM BTA.
• Embodiments of slurries according to the present invention may also be provided with amounts of molybdenum sulfide (MoS 2 ) as a lubricant. It has been found that the addition of molybdenum sulfide particles increases the polish rate of copper for slurries containing KI0 3 and PAA.
• Molybdenum sulfide particles may have mean diameters in the range of about 0.01 to about 1 micron.
• Molybdenum sulfide particles may be present in amounts ranging from about 0.1 to about 10 wt.% MoS 2 , such as about 0.5 to about 5 wt.% MoS 2 , and more preferably in an amount of about 1 wt.% MoS 2 .
• Molybdenum sulfide particles having the size ranges herein are commercially available from the Climax Molybdenum Company of Ft. Madison, Iowa (US).
• the pH of embodiments of slurries according to the present invention may be in the range of about 1 to about 14, such as a pH in the range of about 3 to about 7, and preferably having a pH of 4.
• the pH of embodiments of slurries according to the present invention may be adjusted by the addition of suitable acids (e.g., hydrochloric acid (HC1)) or bases (e.g., potassium hydroxide (KOH)), as would be known by persons having ordinary skill in the art.
• suitable acids e.g., hydrochloric acid (HC1)
• bases e.g., potassium hydroxide (KOH)
• planarizing slurries according to the invention may also be provided with supplemental ceramic/metal oxide particles.
• supplemental ceramic/metal oxide particles used in the aqueous slurry may comprise any one or a mixture of silica, ceria, aluminia, zirconia, titania, magnesia, iron oxide, tin oxide, and germania.
• Embodiments of slurries according to the present invention exhibit high polish rates for copper when used in the CMP process.
• polish rates with the KIO 3 -based slurries of the present invention are high for copper
• the post-polish surface of the copper tended to be covered with a thick, uneven misty layer with roughness values as high as about 150 nm as measured by a non-contact optical prof ⁇ lometer.
• the CMP polishing step may be followed by a buffing step.
• the buffing step involved additionally polishing the copper surface with a dilute suspension of H 2 O , glycine, BTA, and colloidal silica in de-ionized water at a pH of 4.
• H 2 0 2 -based buffing step is that H 2 0 2 reacts spontaneously with molybdenum oxide, thus removing residual amounts of molybdenum oxide that may remain on the surface.
• Very clean and smooth copper surfaces were obtained after subsequent buffing, some with roughness values as low as 0.35 nm as measured by a non-contact optical prof ⁇ lometer.
• Polishing selectivity of one embodiment of a slurry of the present invention between Cu, Ta, and silicon oxide (Si0 ) was determined to be 235:1:1 for Cu:Ta:SiO 2 , as presented in Example 24.
• Examples 25 and 26 involve the addition of ethylene diamine terra acetic acid (EDTA) to test the complexing ability of EDTA with copper ions.
• the polish rates for the two specified slurry compositions are presented in Table 5.
• Table 5 In order to provide further information regarding the invention, the following examples are provided. The examples presented below are representative only and are not intended to limit the invention in any respect.
• Examples 1-15 Slurries of examples 1-15 were used to polish a copper disk having a diameter of 1.25 inches.
• the CMP polisher was a Struers DAP® with an IC-1400, k-groove polishing pad.
• the carrier remained stationary (i.e., was not rotated).
• the rotation rate of the platen was 90 revolutions per minute (rpm).
• the down-force placed on the copper disk was 6.3 pounds per square inch (psi).
• the slurry flow rate was 60 ml/min.
• the amount of copper removed from the surface of the disk by CMP was determined by measuring the weight difference of the copper disk both before and after polishing, taking into consideration the density of the Cu material, the area of the disk that was polished, and the polishing time.
• Examples 1-10 all contained 3 wt.% molybdenum oxide (M0O 2 ) in deionized water.
• the mean particle size of molybdenum oxide for examples 1-10 was 1 micron (1000 nm).
• the mean particle size of molybdenum oxide for examples 11-15 was 150 nm.
• Various amounts and types of oxidizing agents were added, as identified in Table 1.
• Example 11 contained 1.5 wt.% MoO 2 with 3 wt.% hydroxylamine hydrochloride ((NH 2 OH)Cl) as an oxidizing agent.
• Example 12 contained 1.5 wt.% Mo0 2 with 3 wt.%) potassium permanganate (KMn0 4 ) as the oxidizing agent.
• Examples 13-15 all contain 3 wt.% KIO 3 with varying amounts of MoO 2 , as noted.
• the pH of slurries for examples 1-15 was adjusted to 4.0 by the addition of hydrochloric acid (HC1) or potassium hydroxide (KOH).
• HC1 hydrochloric acid
• KOH potassium hydroxide
• Examples 16-18 Slurries of examples 16-18 were used to polish a copper film deposited on a silicon substrate by sputter deposition.
• the copper film had a diameter of 6 inches.
• the CMP polisher was a Westech Model
• the carrier was rotated at a rate of 40 rpm.
• the platen was rotated at 40 rpm.
• the down-force placed on the copper film was 6 pounds per square inch (psi).
• the slurry flow rate was set at 200 ml/min.
• the amount of copper removed from the surface of the silicon substrate by CMP was determined by measuring the sheet resistance of the Cu film both before and after polishing at 17 points spread across the film utilizing a home-made paper mask and a 4-point probe. Sheet resistance was measured at the same points on the film before and after polishing.
• the measured sheet resistances both before and after polishing were then converted to respective film thicknesses before and after polishing based on the resistivity of the Cu material, the current applied, and the voltage across the 4-point probe.
• the difference between the starting and final thicknesses as 17 points were calculated, an average thickness loss was obtained which was then divided by the polish time to give the polish rate in nm/min.
• the slurries all contained 3 wt.% molybdenum oxide (Mo0 2 ) in deionized water and with a potassium iodate (KIO 3 ) oxidizing agent present in an amount of 3 wt.%.
• the mean particle size of the molybdenum oxide for examples 16-18 was 1 micron (1000 nm).
• Example 17 added 1 wt.% PAA to the slurry.
• Example 18 added 1 wt.% PAA and 1 wt.% molybdenum sulfide (MoS 2 ) to the slurry.
• the pH of the slurries of examples 16-18 was adjusted to 4.0 by the addition of hydrochloric acid (HC1) or potassium hydroxide (KOH).
• HC1 hydrochloric acid
• KOH potassium hydroxide
• Examples 19-23 Slurries of examples 19-23 were used to polish a copper film deposited on a silicon substrate by sputter deposition.
• the copper film had a diameter of 6 inches.
• the CMP polisher was a Westech Model
• the slurry flow rate was set at 200 ml/min.
• the amount of copper removed from the surface of the silicon substrate by CMP was determined by measuring the sheet resistance of the Cu film both before and after polishing at 17 points spread across the film utilizing a home-made paper mask and a 4-point probe. Sheet resistance was measured at the same points on the film before and after polishing. The measured sheet resistances both before and after polishing were then converted to respective film thicknesses before and after polishing based on the resistivity of the Cu material, the current applied, and the voltage across the 4-point probe. The difference between the starting and final thicknesses as 17 points were calculated, an average thickness loss was obtained which was then divided by the polish time to give the polish rate in nm/min.
• the slurries all contained 3 wt.% molybdenum oxide (Mo0 2 ) in deionized water and with a potassium iodate (KIO3) oxidizing agent present in an amount of 3 wt.%.
• the mean particle diameter of the molybdenum oxide for examples 19-23 was 150 nm.
• Example 20 added 1 mM benzotriazole (BTA) to the slurry.
• Example 21 added 1 wt.% polyacrylic acid (PAA) to the slurry.
• Example 22 added 0.1 wt.% cetyl pyridinium chloride (CPC) to the slurry.
• Example 23 added 2 wt.% PAA and 1 mM BTA to the slurry.
• the pH of the slurries of examples 19-23 was adjusted to 4.0 by the addition of hydrochloric acid (HC1) or potassium hydroxide (KOH).
• HC1 hydrochloric acid
• KOH potassium hydroxide
• EXAMPLE 24 Silicon wafers (6 inch diameter) having a 0.3 micron Ta layer deposited by sputter deposition and wafers having a 1 micron Si ⁇ 2 layer applied by thermal oxidation were separately polished with a polishing slurry.
• the amount of copper and Ta removed was determined using a four-point probe, and Si ⁇ 2 removed from the surface of the silicon wafer by CMP was measured using an optical interferometer, in order to determine the rate of removal in terms of nm of material removed per minute.
• the slurry utilized comprised 3 wt% molybdenum oxide (M0O2) in deionized water with potassium iodate (KIO 3 ) oxidizing agent present in an amount of 3 wt.%.
• the mean particle size of the molybdenum oxide for example 24 was 1 micron (1000 nm).
• the CMP polisher was a Westech Model 372 with an IC-1400, k-groove polishing pad.
• the carrier was rotated at a rate of 40 rpm.
• the platen was also rotated at 40 rpm.
• the down-force placed on the copper film was 6 pounds per square inch (psi).
• the slurry flow rate was 200 ml/min.
• the slurry composition and polishing rates for Cu, Ta, and SiO 2 are presented in Table 4. TABLE 4
• EXAMPLES 25 and 26 Slurries of examples 25 and 26 were used to polish a copper disk having a diameter of 1.25 inches.
• the CMP polisher was a Struers DAP® with an IC-1400, k-groove polishing pad.
• the carrier remained stationary (i.e., was not rotated).
• the rotation rate of the platen was 90 revolutions per minute (rpm).
• the down-force placed on the copper disk was 6.3 pounds per square inch (psi).
• the slurry flow rate was 60 ml/min.
• the amount of copper removed from the surface of the disk by CMP was determined by measuring the weight difference of the copper disk both before and after polishing, taking into consideration the density of the Cu material, the area of the disk that was polished, and the polishing time.
• examples 25 and 26 all contained 3 wt.% molybdenum oxide (MoO 2 ) in deionized water.
• the mean particle size of molybdenum oxide for both examples 25 and 26 was 1 micron (1000 nm).
• Various amounts and types of oxidizing agents were added, as identified in Table 5.
• Slurries of both examples included the addition of 1 wt.% ethylene diamine terra acetic acid (EDTA) to test the complexing ability of EDTA with copper ions.
• the slurry compositions and polishing rates for the copper disk are presented in Table 5.
• an aqueous slurry may comprise molybdenum trioxide (M0O 3 ) and an oxidizing agent.
• M0O 3 may be present in an amount of about 0.1 to about 10 wt. %, such as about 0.5 to about 10 wt. %, and more preferably in an amount of about 0.5 to about 5 wt. %.
• the molybdenum trioxide (M0O 3 ) may be provided in powder form such that the molybdenum trioxide (MoO ) visibly dissolves or substantially visibly dissolves in the oxidizing agent.
• the molybdenum trioxide power may have a mean particle size of about 10,000 nm (10 microns) and more preferably less than about 1,000 nm (1 micron), as measured by a Horiba laser scattering analyzer.
• molybdenum trioxide (M0O 3 ) powders having these sizes are visibly dissolved in an aqueous solution of deionized water and the oxidizing agent.
• dissolved and visibly dissolved refer to solutions wherein the particles of M0O 3 are at least partially, although not necessarily completely, dissolved.
• an aqueous slurry may comprise molybdic acid.
• the dissolution of molybdenum trioxide in an aqueous solution of deionized water and an oxidizing agent may form molybdic acid.
• molybdic acid may be formed by dissolving molybdenum metal, molybdenum oxides, or molybdates in an oxidizing medium.
• molybdic acid refers to any compound containing molybdenum and capable of transferring a hydrogen ion in solution.
• Embodiments of the aqueous slurry of the present invention utilizing molybdic acid may comprise the same oxidizing agents, complexing agents, surfactants, corrosion inhibitors, acids or bases, and supplemental ceramic/metal oxide particles as are listed below for the molybdenum trioxide aqueous slurry.
• the M0O 3 particles may be produced from a variety of molybdenum-containing precursor materials, such as, for example, ammonium molybdates and related compounds, as well as molybdenum oxides prepared from a variety of processes known in the art, wherein molybdenum precursors and products can be made into particles of varying sizes.
• Molybdenum trioxide particles suitable for use in the present invention are commercially available from a wide variety of sources, including the Climax Molybdenum Company of Ft. Madison, Iowa (US).
• the oxidizing agent used with molybdenum trioxide (M0O 3 ) may comprise any one or a mixture of hydrogen peroxide (H 2 O 2 ), ferric nitrate (Fe(N0 3 ) 3 ), potassium iodate (KIO 3 ), nitric acid (HNO 3 ), potassium permanganate (KMnO 4 ), potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate ((NH 4 ) 2 S 2 ⁇ s) 5 potassium periodate (KIO 4 ), and hydroxylamine (NH 2 OH).
• Hydrogen Peroxide oxidizing agent may be present in concentrations ranging from about 0.5 to about 20 wt% H 2 0 2 , such as about 1 to about 10 wt% H 2 0 , and more preferably in a concentration of about 5 wt% H 2 O 2 .
• Ferric Nitrate oxidizing agent may be present in concentrations ranging from about 0.05 to about 0.2 molar (M) Fe(NO 3 ) 3 , such as about 0.1 to about 0.2 M Fe(N0 3 ) 3 , and more preferably in a concentration of about 0.2 M Fe(NO 3 ) 3.
• Potassium Iodate oxidizing agent may be present in concentrations ranging from about 1 to about 5 wt% KIO 3 , such as about 1 to about 3 wt% KIO , and more preferably in a concentration of about 3 wt% KIO 3.
• Nitric Acid oxidizing agent may be present in concentrations ranging from about 0.5 to about 2 wt% HNO 3 , such as about 1 to about 2 wt% HNO 3 , and more preferably in a concentration of about 2 wt% HNO 3.
• Potassium Permanganate oxidizing agent may be present in concentrations ranging from about 1 to about 5 wt% KMn ⁇ 4 , such as about 2 to about 4 wt% KMnO 4 , and more preferably in a concentration of about 3 wt% KMn0 4. Potassium Persulfate oxidizing agent may be present in concentrations ranging from about 1 to about 5 wt% K 2 S 2 0 8 , such as about 2 to about 4 wt% K 2 S 2 0 8 , and more preferably in a concentration of about 3 wt% K 2 S2 ⁇ 8.
• Ammonium Persulfate oxidizing agent may be present in concentrations ranging from about 1 to about 5 wt% (NI ⁇ S ⁇ s, such as about 2 to about 4 wt% (NH 4 ) 2 S 2 O 8 , and more preferably in a concentration of about 3 wt% (NH 4 ) 2 S 0 8.
• Potassium Periodate oxidizing agent may be present in concentrations ranging from about 1 to about 5wt%-KIO 4 , such as about 2 to about 4 wt% KI0 4 , and more preferably in a concentration of about 3 wt% KI0 .
• Hydroxylamine oxidizing agent may be present in concentrations ranging from about 1 to about 5 wt% NH 2 OH, such as about 2 to about 4 wt% NH 2 OH, and more preferably in a concentration of about 3 wt% NH 2 OH Additionally, complexing agents may be used in the molybdenum trioxide (M0O 3 ) aqueous slurry.
• M0O 3 molybdenum trioxide
• Complexing agents may comprise any one or a mixture of glycine (C 2 H 5 N0 2 ), alanine (C 3 H 7 N0 2 ), amino butyric acids (C 4 H 9 NO 2 ), ethylene diamine (C 2 H 8 N 2 ), ethylene diamine tetra acetic acid (EDTA), ammonia (NH ), family of mono, di, and tri-carboxylic acids like citric acid (C 6 H 8 O 7 ), phthalic acid (C 6 -H 4 (COOH) 2 ), oxalic acid (C 2 H 2 0 ), acetic acid (C2EI 4 O 2 ), and succinic acid (C 4 H 6 O 4 ) and family of amino benzoic acids (C 7 H 7 NO 2 ).
• glycine C 2 H 5 N0 2
• alanine C 3 H 7 N0 2
• amino butyric acids C 4 H 9 NO 2
• ethylene diamine C 2 H 8 N 2
• EDTA ethylene di
• Glycine complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 2 H5NO 2 , such as about 0.1 to about 3 wt.% C 2 H 5 NO 2 , and more preferably in an amount of about 0.5 wt.% C 2 H 5 N0 2 .
• Alanine complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C3H 7 NO2, such as about 0.1 to about 3 wt.% C3H7NO 2 , and more preferably in an amount of about 0.5 wt.% C 3 H 7 N0 2 .
• Amino butyric acid complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 4 H 9 NO 2 , such as about 0.1 to about 3 wt.% H 9 NO 2 , and more preferably in an amount of about 0.5 wt.% C 4 H 9 NO 2 .
• Ethylene diamine complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 2 H 8 N 2 , such as about 0.1 to about 3 wt.% C 2 H 8 N 2 , and more preferably in an amount of about 0.5 wt.% C 2 H 8 N 2 .
• Ethylene diamine tetra acetic acid complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% EDTA, such as about 0.1 to about 3 wt.% EDTA, and more preferably in an amount of about 0.5 wt.% EDTA.
• Ammonia complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% NH 3 , such as about 0.1 to about 3 wt.% NH 3 , and more preferably in an amount of about 0.5 wt.% NH 3 .
• Citric acid complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 6 H 8 O 7 such as about 0.1 to about 3 wt.% C 6 H 8 0 7 , and more preferably in an amount of about 0.5 wt.% C 6 H 8 O 7 .
• Phthalic acid complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% Ce-ft ⁇ COOITh such as about 0.1 to about 3 wt.%) and more preferably in an amount of about 0.5 wt.% C 6 H (COOH) 2 .
• Oxalic acid complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 2 H 2 O 4 such as about 0.1 to about 3 wt.% C 2 H 2 0 , and more preferably in an amount of about 0.5 wt.% C 2 H 2 ⁇ 4 .
• Acetic acid complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 2 EI- 4 O 2 such as about 0.1 to about 3 wt.% C 2 H 4 O 2 , and more preferably in an amount of about 0.5 wt.% C 2 H 4 O 2 .
• Succinic acid complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 4 H 6 O 4 such as about 0.1 to about 3 wt.% C 4 H 6 ⁇ 4 , and more preferably in an amount of about 0.5 wt.% C 4 H 6 O 4 .
• Amino benzoic acids as a complexing agent may be present in amounts ranging from about 0.1 to about 5 wt.% C 7 H7NO 2 such as about 0.1 to about 3 wt.% C 7 H7NO 2 , and more preferably in an amount of about 0.5 wt.% C 7 H 7 N0 2 .
• Embodiments of slurries containing molybdenum trioxide (M0O3) may also be provided with a nonionic surfactant, an anionic surfactant, or a cationic surfactant.
• the anionic surfactant used in the aqueous slurry may comprise any one or a mixture of polyacrylic acid (PAA), a carboxylic acid or its salt, a sulfuric ester or its salt, a sulfonic acid or its salt, a phosphoric acid or its salt, and a sulfosuccinic acid or its salt.
• the cationic surfactant used in the aqueous slurry may comprise any one or a mixture of a primary amine or its salt, a secondary amine or its salt, a tertiary amine or its salt, and a quaternary amine or its salt.
• the nonionic surfactant may be one or a mixture of one of the family of polyethylene glycols.
• the molybdenum trioxide (M0O3) aqueous slurry may also be provided with a copper corrosion inhibitor which may comprise any one or a mixture of heterocyclic organic compounds including benzotriazole (BTA), benzimidazole, poly triazole, phenyl triazole, thion and their derivatives.
• the slurry may contain any combination of these surfactants and corrosion inhibitors.
• a preferred anionic surfactant used in the M0O3 slurry is a salt of dodecyl benzene sulfonic acid.
• DBSA dodecyl benzene sulfonic acid
• Dodecyl benzene sulfonic acid surfactant and salts thereof may be present in amounts ranging from about 0.00001 to about 1 wt.%) (DBSA), such as about 0.0001 to about 0.5 wt.% (DBSA), and more preferably in an amount of about 0.001 wt.% (DBSA).
• a preferred copper corrosion inhibitor used in the M0O 3 slurry is benzotriazole (BTA). The addition of BTA to the slurry brought down the dissolution rates drastically, to less than 50 nm/minute. See Examples 30 - 33.
• Benzotriazole (BTA) copper corrosion inhibitor may be present in concentrations ranging from about 1 to about 20 milli-molar (mM) BTA, such as about 1 to about 10 mM BTA, and more preferably in a concentration of about 10 mM BTA.
• the pH of embodiments of MoO 3 slurries according to the present invention may be in the range of about 1 to about 14, such as a pH in the range of about 1 to about 5, and preferably having a pH of about 2.6.
• the pH of embodiments of slurries according to the present invention may be adjusted by the addition of suitable acids (e.g., acetic acid) or bases (e.g., potassium hydroxide), as would be known by persons having ordinary skill in the art.
• M0O 3 polishing slurries according to the invention may also be provided with supplemental ceramic/metal oxide particles.
• supplemental ceramic/metal oxide particles used in the aqueous slurry may comprise any one or a mixture of silica, ceria, zirconia, titania, magnesia, iron oxide, tin oxide, and germania.
• a preferred supplemental ceramic/metal oxide used in the M0O 3 slurry is colloidal silicon dioxide (Si0 2 ).
• Colloidal silicon dioxide (SiO 2 ) may have an average particle size of about 20 nm.
• Embodiments of M0O 3 slurries according to the present invention exhibit high polish rates for copper when used in the CMP process.
• the copper dissolution rate gives an indication of the rate at which copper would be removed in those regions of the wafer that are not subject to mechanical abrasion.
• polish rates can be tuned according to a user's requirements and dissolution rates can be minimized.
• blanket copper wafer polishing rates of one embodiment of an M0O 3 slurry of the present invention were determined to be as high as about 1200 nm/minute with post CMP surface roughness of about 1 nm.
• the slurries of Examples 29 & 30 were filtered to remove particles above 1,000 nm (1 micron) in size and 1.0 wt % of 20 nm colloidal SiO 2 abrasives were added.
• the post-polish surface of the copper was good with post CMP surface roughness values of about 1 nm as measured by a non-contact optical profilometer. If higher post-polish surface quality is desired, the CMP polishing step may be followed by a buffing step. In one embodiment, the buffing step may involve additionally polishing the copper surface with deionized water for about five to about fifteen seconds at a pH in the range of about 5 to about 7.
• the advantage of using a deionized water rinse buffing step is the removal of reactive chemicals from the wafer-pad interface, which removes residual amounts of molybdenum oxide that may remain on the surface of the wafer-pad.
• Clean and smooth copper surfaces were obtained after subsequent buffing using a deionized water rinse, some with roughness values as low as about 0.5 to 0.6 nm as measured by a non-contact optical profilometer.
• very high polish rates e.g., about 900 nm/minute
• very low post CMP roughness e.g., about 0.5 to 0.6 nm
• Copper coupon dissolution rate in this slurry was low (e.g., about 40 nm/minute).
• Examples 27 & 28 Slurries of examples 27 and 28 were used to polish a copper disk having a diameter of 32 millimeters (mm).
• the CMP polisher was a Struers DAP® with an IC-1400, k-groove polishing pad.
• the carrier remained stationary (i.e., was not rotated).
• the rotation rate of the platen was 90 revolutions per minute ( ⁇ m).
• the down-force placed on the copper disk was 6.3 pounds per square inch (psi).
• the slurry flow rate was 60 ml/min.
• the amount of copper removed from the surface of the disk by CMP was determined by measuring the weight difference of the copper disk both before and after polishing, taking into consideration the density of the copper material, the area of the disk that was polished, and the polishing time. This was then converted into the rate of removal in terms of nm of copper removed per minute.
• Copper coupon dissolution experiments were performed in a 500 ml. glass beaker containing 400 ml. of the chemical solution. A copper coupon (i.e. 99.99% pure) of dimensions 25 x 25 x 1 mm was used as the experimental sample.
• the copper coupon was hand polished with 1500 grit sandpaper, washed with dilute hydrochloric acid (HC1) to remove copper oxides from the surface, dried in an air stream, and then weighed.
• HC1 dilute hydrochloric acid
• Example 27 contained 1.0 wt.% M0O 3 in deionized (DI) water and Example 28 contained 1.0 wt. % MoO 3 in deionized (DI) water with 5.0 % H 2 O 2 and 1.0 % glycine as an oxidizing agent and complexing agent, respectively.
• the natural pH of the Example 27 slurry was about 1.8.
• the natural pH of the Example 28 slurry was about 2.6.
• Example 27 The remaining percentages not specified in the below table for the slurry compositions is the percentage of deionized water.
• the M0O 3 comprises 1% of the slurry composition and the deionized water comprises the remaining 99% of the slurry composition.
• the slurry compositions, copper coupon dissolution rates and polishing rates for the copper disk of Examples 27 and 28 are presented in Table 6.
• EXAMPLES 29 - 34 Slurries of examples 29-34 were used to polish a copper film deposited on a silicon substrate by sputter deposition.
• the copper film had a diameter of 6 inches.
• the CMP polisher was a Westech Model 372 with an IC-1400, k-groove polishing pad.
• the carrier was rotated at a rate of 75 ⁇ m.
• the platen was rotated at 75 ⁇ m.
• the down-force placed on the copper film was 4 pounds per square inch (psi).
• the slurry flow rate was set at 200 ml/min.
• the amount of copper removed from the surface of the silicon substrate by CMP was determined by measuring the sheet resistance of the copper film both before and after polishing at 17 points spread across the film utilizing a home-made paper mask and a 4-point probe. Sheet resistance was measured at the same points on the film before and after polishing. The measured sheet resistances both before and after polishing were then converted to respective film thicknesses before and after polishing based on the resistivity of the copper material, the current applied, and the voltage across the 4-point probe. The difference between the starting and final thicknesses as 17 points were calculated, an average thickness loss was obtained which was then divided by the polish time to give the polish rate in nm/min. Copper coupon dissolution experiments were performed in a 500 ml. glass beaker containing 400 ml.
• a copper coupon (i.e. 99.99% pure) having dimensions of 25 x 25 x 1 mm was used as the experimental sample.
• the copper coupon was hand polished with 1500 grit sandpaper, washed with dilute hydrochloric acid (HC1) to remove any copper oxide from the surface, dried in an air stream, and then weighed.
• the copper coupon was then immersed in the solution for three minutes while continuously stirring the solution. After the experiment, the copper coupon was washed repeatedly with a deionized (DI) water rinse, dried in an air stream, and weighed. Weight loss was used to calculate the dissolution rate.
• DI deionized
• Example 29 contained 0.5 wt.% molybdenum trioxide (M0O 3 ) in deionized water. At the end of the wafer polishing a deionized (DI) water rinse was applied for five seconds.
• Example 29 contained 0.5% M0O3 + 5.0 % H 2 0 2 + 1.0 % glycine + 5 mM BTA - filtered with 100 nm filter + 1.0 % SiO 2 .
• the natural pH of the Example 29 slurry was about 2.9.
• Example 30 contained 0.5% M0O 3 + 5.0% H 2 O 2 + 1.0% glycine + 10 mM BTA - filtered with 100 nm filter + 1.0% SiO 2 .
• Example 31 contained 0.5% M0O 3 + 5% H 2 O 2 + 0.5 % glycine + 10 mM BTA - filtered with 100 nm filter + 0.1% SiO 2 .
• the natural pH of the Example 31 slurry was about 2.6.
• Example 32 contained 0.5% M0O3 + 5% H 2 O 2 + 0.5 % glycine + 10 mM BTA - filtered with 100 nm filter + 0.5% SiO 2 .
• the natural pH of the Example 32 slurry was 2.6.
• Example 33 contained 0.5% MoO 3 + 5% H 2 0 2 + 0.5 % glycine + 10 mM BTA - filtered with 100 nm filter + 1.0 % Si0 2 .
• the natural pH of the Example 33 slurry was about 2.6.
• Example 34 contained 0.5% M0O 3 + 5% H 2 0 2 + 0.5 % glycine + 10 mM BTA + 0.001% SDBS - filtered with 100 nm filter + 1.0 % SiO 2 .
• the natural pH for the slurry of Example 34 was about 2.6.
• the average size of the particles of SiO 2 in the slurries of Examples 29 - 34 was about 20 nm.
• Examples 35 - 37 Slurries of Examples 35 - 37 were used to polish six inch copper blanket films.
• the CMP polisher was a Westech 372 Wafer Polisher with an IC-1400, k-groove polishing pad.
• the rotation rate of the carrier was 75 revolutions per minute (rpm).
• the rotation rate of the platen was also 75 revolutions per minute (rpm).
• the down-force placed on the copper blanket film was 4.0 pounds per square inch (psi).
• the slurry flow rate was 200 ml/min.
• the amount of copper removed from the surface of the silicon substrate by CMP was determined by measuring the sheet resistance of the copper film both before and after polishing at 17 points spread across the film utilizing a home-made paper mask and a 4-point probe.
• Sheet resistance was measured at the same points on the film before and after polishing.
• the measured sheet resistances both before and after polishing were then converted to respective film thicknesses before and after polishing based on the resistivity of the copper material, the current applied, and the voltage across the 4-point probe.
• the difference between the starting and final thicknesses as 17 points were calculated, an average thickness loss was obtained which was then divided by the polish time to give the polish rate in nm/min.
• Copper coupon dissolution experiments were performed in a 500 ml. glass beaker containing 400 ml. of the chemical solution.
• a copper coupon (i.e. 99.99% pure) having dimensions of 25 x 25 x 1 mm was used as the experimental sample.
• Example 35 contained 1% MoO 3 + 5.0 % H 2 0 2 + 1.0 % glycine + 5 mM BTA - filtered with 100 nm filter + 1.0 % Si0 2 .
• the natural pH of the Example 35 slurry was about 2.6.
• Example 36 contained 1% Mo0 3 + 5.0 % H 2 0 2 + 1.0 % glycine + 10 mM BTA - filtered with 100 nm filter + 1.0 % SiO 2 .
• the natural pH of the Example 36 slurry was about 2.6.
• Example 37 contained 1% M0O 3 + 5.0 % H 2 0 2 + 1.0 % glycine + 15 mM BTA - filtered with 100 nm filter + 1.0 % SiO 2 .
• the natural pH of the Example 37 slurry was about 2.6.
• the remaining percentages not specified in the below table for the slurry compositions is the percentage of deionized water in the slurry.
• the slurry compositions and polishing rates for the copper wafer along with the copper coupon dissolution rates for Examples 35-37 are presented in Table 8.
• the three electrodes are immersed in a 250 ml of the chemical solution and the potential of the working electrode was scanned from -750 mV to about 1000 mV w.r.t. open circuit potential (OCP) and the resulting current density was monitored using a EG&G Princeton Applied Research model 352 softcorr TM II corrosion software.
• the general method for pattern wafer polishing is to polish the bulk copper initially at a high rate and as planarization is achieved, the copper is removed at a lower rate in order to minimize dishing of copper lines.
• the Mo0 3 slurry of the present invention may be tuned for this general method of polishing at a higher rate and then a lower rate.
• Tantalum dissolution and disk polish rates with the same MoO 3 slurry were both less than 5 nm/minute.
• the claimed product and process collectively represent an important development in CMP technology.
• the product and process discussed above are novel, distinctive, and highly beneficial from a technical and utilitarian standpoint. Having herein set forth preferred embodiments of the present invention, it is anticipated that suitable modifications can be made thereto which will nonetheless remain within the scope of the invention.
• the invention shall therefore only be construed in accordance with the following claims:

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