Classifications

• • 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
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
  • H10P52/40—Chemomechanical polishing [CMP]
  • H10P52/403—Chemomechanical polishing [CMP] of conductive or resistive materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
• • 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
  • C09G1/04—Aqueous dispersions
• • 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
  • C09G1/06—Other polishing compositions
• • 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
  • C09K13/00—Etching, surface-brightening or pickling compositions
• • 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
  • C09K13/00—Etching, surface-brightening or pickling compositions
  • C09K13/02—Etching, surface-brightening or pickling compositions containing an alkali metal hydroxide
• • 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
  • C09K13/00—Etching, surface-brightening or pickling compositions
  • C09K13/04—Etching, surface-brightening or pickling compositions containing an inorganic acid
  • C09K13/06—Etching, surface-brightening or pickling compositions containing an inorganic acid with organic material
• • 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
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P52/00—Grinding, lapping or polishing of wafers, substrates or parts of devices
  • H10P52/40—Chemomechanical polishing [CMP]
  • H10P52/402—Chemomechanical polishing [CMP] of semiconductor materials

Definitions

• llus disclosure relates to semiconductor device manufacturing, and, in particular, to the removal and etching of poiycrystalline materials, such as metals.
• various metals formed on a substrate may be removed by patterned etching, chemical -mechanical polishing (CMP), as well as other techniques.
• CMP chemical -mechanical polishing
• a variety of techniques are known for etching layers on a substrate, including plasma-based or vapor phase etching (otherwise referred to as dry etching) and liquid based etching (otherwise referred to as wet etching).
• CMP Chemical -mechanical polishing
• Ruthenium is a noble metal currently being considered as a replacement tor copper in back end of line (BEOL) metallization, as well as front end of line (FEOL) features such as buried power rails (power rails positioned below active devices). Ruthenium’s nobility, however, makes Ru difficult to etch and planarize.
• ruthenium etchants contain strong oxidizers, such as sodium hypochlorite, ceric ammonium nitrate and periodic acid, which oxidize the ruthenium surface to create ruthenium tetroxide (RuCh).
• strong oxidizers such as sodium hypochlorite, ceric ammonium nitrate and periodic acid, which oxidize the ruthenium surface to create ruthenium tetroxide (RuCh).
• tire most effective etchants, ceric ammonium nitrate and sodium hypochlorite are problematic because they pose a metal contamination hazard in the subsequently formed device. For example, incorporation of trace amounts of sodium or cerium in the front end of line can significantly degrade transistor performance.
• Periodic acid on the other hand, is expensive and cannot be used to provide a cost-effective etch process for ruthenium.
• Tire present disclosure provides a new' corrosion control chemistry for use in ruthenium (Ru) CMP processes. More specifically, the present disclosure provides anew' ruthenium CMP slurry chemistry that uses halogenation of the ruthenium surface to form ruthenium halide or ruthenium oxyhalide surface intermediates, and reactive dissolution to chemically remove the ruthenium halide or ruthenium oxyhalide surface intermediates.
• Halogenation of the ruthenium surface can be accomplished using radical halogenation of chemical halogenating agents. On its own, halogenation is self-limiting, and the kinetics of reactive dissolution are temperature dependent. Tire self-limiting nature of halogenation limits piting of the ruthenium surface. The temperature dependent kinetics of dissolution further aid in planarization of the ruthenium surface as the mechanical polishing process raises the local temperature around high points on the surface.
• an improved chemical-mechanical polishing (CMP) process for planarizing a ruthenium surface.
• a ruthenium surface e.g., a post-etch ruthenium surface
• a CMP slurry' containing a halogenation reagent, which reacts with the ruthenium surface to create a ruthenium halide or oxyhalide surface, and a ligand for ligand-assisted reactive dissolution of the ruthenium halide or oxyhalide surface.
• Relative amounts of the halogenation agent and the ligand can be controlled in the CMP slurry', so as to provide a diffusion-limited etch process that improves post-etch surface morphology, while providing high material removal rates.
• halogenation reagents such as, e.g., trichloroisocyanuric acid (TCCA)
• a non-aqueous solvent such as, e.g, ethyl acetate (EA)
• TCCA trichloroisocyanuric acid
• EA ethyl acetate
• ligand-assisted reactive dissolution is used to facilitate chemical removal of the ruthenium halide or oxyhalide surface.
• ligands such as, e.g., acetyl acetone (ACAC) or aminopolycarboxylic acids
• ACAC acetyl acetone
• aminopolycarboxylic acids can be used for reactive dissolution of the ruthenium halide or oxyhalide surface.
• a composition comprising a new CMP slum’.
• the new CMP slum may generally include a solvent, a halogenation agent that halogenates a ruthenium surface to form a halogenated ruthenium surface, a ligand that reacts with the halogenated ruthenium surface to dissolve the halogenated ruthenium surface, and a catalyst that increases the rate of a ligand exchange reaction with the halogenated ruthenium surface.
• relative amounts of the halogenation agent and the ligand in the CMP slurry may be selected to provide a rate of halogenation of the ruthenium surface that is greater than a rate of dissolution of the halogenated ruthenium surface.
• the CMP skirry described herein includes a halogenating agent, but does not include an oxide-forming oxidizing agent.
• an oxide-forming oxidizing agent is an oxidizing agent that reacts with the ruthenium surface to form rutheniumoxide layer on the ruthenium surface.
• a halogenating agent may halogenate and chemically oxidize the ruthenium surface, it does not react with the ruthenium surface to form a ruthenium -oxide layer on the ruthenium surface.
• the CMP slurry described herein may include a halogenating agent and an oxide-forming oxidizing agent.
• the CMP slurry may further contain a predetermined amount of water or dissolved oxygen.
• an oxide-forming oxidizing agent such as water or dissolved oxygen
• a halogenated ruthenium surface containing a ruthenium-oxide-halogen species is created on the ruthenium surface. Since the ruthenium-oxide-halogen species is generally more soluble than the halogenated ruthenium surface layer, the presence of ruthenium-oxide-halogen species increases the material removal rate in the CMP process.
• the halogenation agent included within the CMP slurry may be a chlorination agent.
• the chlorination agent may react with the ruthenium surface to form a chlorinated ruthenium surface, and the ligand may be reactive w 7 ith the chlorinated ruthenium surface.
• the halogenation agent may include a chlorination agent dissolved in a solvent.
• the chlorination agent may be trichloroisocyanuric acid (TCCA), oxalyl chloride, thionyl chloride or N-chlorosuccinimide, and the solvent may be ethyl acetate, acetone, acetonitrile, or a chlorocarbon.
• the halogenation agent may react with the ruthenium surface to form a self-limiting RuCh passivation layer.
• the halogenation agent disclosed herein is not strictly limited to chlorination agents.
• the halogenation agent may be a fluorinating agent.
• the fluorinating agent may react with the ruthenium surface to form a fluorinated ruthenium surface, and the ligand may be reactive with the fluorinated ruthenium surface.
• the halogenation agent may be a brominating agent.
• the brominating agent may react with the ruthenium surface to form a brommated ruthenium surface, and the ligand may be reactive with the brominated ruthenium surface.
• the ligand included within the CMP slurry may include ethylenediaminetetraacetic acid (EDTA), acetylacetone (ACAC), iminodiacetic acid (IDA) or diethylenetriaminepentaacetic acid (DTP A), and the catalyst may be a base.
• bases that may be included within the CMP slurry' to increase the rate of the ligand exchange reaction with the halogenated ruthenium surface include, but are not limited to, potassium hydroxide (KOH), sodium hydroxide (NaOH), ammonium hydroxide (NHrOH) and tetramethylammonium hydroxide ((CHs ⁇ NOH).
• the CMP slurry may be non-aqueous and may include abrasive particles.
• the CMP slurry disclosed herein may use EA as a solvent and may further contain a nanoparticle abrasive (such as silicon dioxide (SiO?.)), a halogenation reagent (such as TCCA), a ligand (such as an aminopolycarboxylic acid) and a base to catalyze the ligand-assisted reactive dissolution.
• a nanoparticle abrasive such as silicon dioxide (SiO?.)
• TCCA halogenation reagent
• a ligand such as an aminopolycarboxylic acid
• the techniques disclosed herein provide a ruthenium CMP process and a ruthenium CMP shiny' that primarily use halogenation to create ruthenium-halogen compounds on the ruthenium surface, and use ligand-assisted reactive dissolution for chemical removal of tlie ruthenium -halogen compounds. Since different bgands react with the halogenated surface at different rates, a variety of different ligands can be used to tune the chemical etch rate achieved during a given CMP process.
• One advantage of the CMP process and CMP slurry described herein is that chemical and mechanical properties of ruthenium-halogen compounds are more amenable to the CMP process. As such, the CMP process and CMP slurry described herein improve smoothing of the post-etch ruthenium surface, while providing high material removal rates.
• the present disclosure provides various embodiments of methods that utilize the new CMP chemistries disclosed herein for planarizing a ruthenium surface.
• the order of discussion of the different steps as described herein has been presented for clarity sake. In general, these steps can be performed in any suitable order.
• each of the different features, techniques, configurations, etc. herein may be discussed in different places of this disclosure, it is intended that each of the concepts can be executed independently of each other or in combination with each other. Accordingly, tlie present invention can be embodied and viewed in many different ways.
• a method is provided herein tor removing ruthenium.
• the method may generally begin by positioning a substrate in a chemical-mechanical polishing (CMP) system, wherein the CMP system includes a polishing pad mounted on a rotatable platen such that the polishing pad can be rotated and moved across a surface of the substrate, and wherein the substrate includes a ruthenium surface.
• CMP chemical-mechanical polishing
• the method may include dispensing a slurry over the polishing pad.
• the method may further include controlling relative amounts of the halogenation agent and the ligand in the slurry, such that a rate of halogenation of the ruthenium surface is greater than a rate of dissolution of the halogenated ruthenium surface.
• said dispensing a slurry over the polishing pad may comprise dispensing a slurry that does not include an oxide-forming oxidizing agent. In other embodiments, said dispensing a slurry over the polishing pad may comprise dispensing a slurry that includes the halogenating agent and an oxide-forming oxidizing agent.
• the halogenation agent may include a chlorination agent, which reacts -with the ruthenium surface to form a chlorinated ruthenium surface.
• the ligand may react with the chlorinated ruthenium surface to dissolve the chlorinated ruthenium surface.
• the catalyst that increases the rate of the ligand exchange reaction with the chlorinated ruthenium surface may be a base.
• FIG. l is a block diagram of a chemical mechanical polishing (CMP) system.
• FIG. 2 is a flowchart diagram illustrating one embodiment of a method utilizing the techniques described herein.
• Ru etchants use ceric ammonium nitrate, periodic acid, and hypochlorite ions to oxidize metallic Ru° to Ru 8+ as RuOr or related hydrated species. These oxidations, however, leave a rough post-etch surface because of the increased reactivity of ruthenium at grain boundaries.
• Another disadvantage of conventional ruthenium wet etch processes is that the reaction products are highly soluble. This solubility leads to oxidation-limited etching, which only’ exacerbates roughness formation during etching.
• These disadvantages are amplified when these same oxidizers are used as part of Ru CMP slurries. As such, new etch chemistries for use in Ru CMP are needed for beter ruthenium removal.
• Hie present disclosure provides new CMP slurry chemistries for planarizing a ruthenium (Ru) surface.
• the Ru CMP slurry’ described herein includes a halogenating agent to chemically modify the ruthenium surface and form a ruthenium halide or oxyhalide passivation layer on the ruthenium surface, a ligand (or ligands) for reactive dissolution of the ruthenium halide or oxyhalide passivation layer, a strong base or other catalyst to increase the rate of the ligand reaction , and abrasive grinding media in a nonaqueous solvent.
• Surfactants or other stabilizers can also be used to help keep all of these components dissolved or suspended in the CMP slurry.
• the CMP slurry chemistry' disclosed herein focuses on oxidizing Ru° to Ru 3+ rather than the higher oxidation states achieved with conventional Ru CMP slurries.
• Using a lower oxidation state has the advantage of providing options for creating both soluble and insoluble ruthenium products.
• the CMP shiny chemistries disclosed herein achieve lower oxidation states by primarily using halogenation, rather than oxidization, of the ruthenium surface to form a ruthenium halide or oxy-’halide passivation layer.
• halogenation may be achieved by exposing the ruthenium surface to a CMP slurry comprising a chlorination agent, a fluorinating agent or a brominating agent.
• Chlorination of the ruthenium surface can be accomplished using a wide variety of chlorination reagents, such as trichloroisocyanuric acid (TCCA), oxalyl chloride, thionyl chloride, and N-chlorosuccinimide. Exposing the ruthenium surface to these chlorination agents chemically modifies the ruthenium surface to form a ruthenium chloride passivation layer, such as but not limited to ruthenium trichloride (RuCh). It is noted that this is not an exhaustive list of all possible chlorination agents that may’ be used to form a ruthenium chloride passivation layer.
• chlorination reagents such as trichloroisocyanuric acid (TCCA), oxalyl chloride, thionyl chloride, and N-chlorosuccinimide.
• Exposing the ruthenium surface to these chlorination agents chemically modifies the ruthenium surface to form
• the ruthenium surface may be exposed to other halogenation agents to form other ruthenium halide or oxyhalide passivation layers.
• fluorination or bromination of the ruthenium surface can be accomplished using fluorinating or brominating agents, such as l-Fluoro-2,4,6-trirnethylpyridinium tetrafluoroborate, N-fluorobenzenesulfonimide, N-bromosucc inimide, or dibromoisocyanuric acid.
• fluorinating or brominating agents such as l-Fluoro-2,4,6-trirnethylpyridinium tetrafluoroborate, N-fluorobenzenesulfonimide, N-bromosucc inimide, or dibromoisocyanuric acid.
• a ruthenium fluoride or ruthenium bromide passivation layer is formed on the ruthenium surface.
• Halogenating agents
• a CMP slurry in accordance with the present disclosure may include TCCA dissolved in a non-aqueous solvent, such as ethyl acetate (EA), acetone, acetonitrile, or a chlorocarbon.
• Ru° reacts quickly to form a self-limiting ruthenium chloride (RuCh) passivation layer when exposed to TCCA in a non-aqueous solvent, such as ethyl acetate.
• the self-limiting ruthenium chloride passivation layer may also contain RuOxCly species if oxide-forming oxidizing agents, such as water or dissolved oxygen, are present during the chlorination reaction.
• Self-limiting means that only a limited thickness of the ruthenium surface is modified or removed, regardless of how long a given etch solution is in contact with the ruthenium surface.
• the self-limiting reaction can be limited by one or more monolayers of reaction or a partial monolayer of reaction.
• the ruthenium chloride passivation layer can be solubilized through ligand exchange reactions. The addition of reactive ligands to the non-aqueous TCCA solution transforms the CMP slurry chemistry described herein from a self-limiting surface passivation to a continuous etch process.
• ligands may be used in the CMP slurry to chemically remove the ruthenium chloride passivation layer through ligand-assisted reactive dissolution.
• ligands such as acetyl acetone (ACAC) or aminopolycarboxylic acids work well for ligand- assisted dissolution of insoluble RuCh
• EDTA Ethylenediaminetetracetic acid
• a wide variety of ligands may be used in the CMP slurry to chemically remove the ruthenium chloride passivation layer through ligand-assisted reactive dissolution.
• ligands such as acetyl acetone (ACAC) or aminopolycarboxylic acids work well for ligand- assisted dissolution of insoluble RuCh
• EDTA Ethylenediaminetetracetic acid
• Alternative ligands for reactive dissolution of insoluble RuCh include, but are not limited to, iminodiacetic acid (IDA) and dietliylenetriaminepentaacetic acid (DTP A).
• EDTA, IDA, and DTPA can be used in aqueous solution, while ACA C can be used in aqueous solution, ethanol, dimethyl sulfoxide (DMSO) or other organic solvents.
• the ligand or ligands included within the CMP slurry can be used to tune the chemical etch rate achieved during a given CMP process. For example, different ligands react with the ruthenium chloride passivation layer (or other halogenated ruthenium surface layer) at different rates. Because the kinetics of the reaction is highly dependent on the reactivity of the ligand used, different ligands may be selected and used to tune the chemical etch rate achieved during a given CMP process.
• the ligand exchange reaction (e.g., substituting EDTA for Cl ligands) is base catalyzed. Therefore, a base is needed in the CMP slurry to deprotonate EDTA (or ACAC) to form the reactive anionic form of the ligand.
• bases such as potassium hydroxide (KOH), sodium hydroxide (NaOH), ammonium hydroxide (NTLiOH), tetramethylammonium hydroxide ((CHsjrNOH), and other strong bases can be used in the CMP slurry to deprotonate the ligand.
• Non-aqueous bases such as quaternary ammonium hydroxides, trialkylamines
• basic solvents such as amino alcohols
• the CMP slurry' described herein may contain TCCA to facilitate a chlorination reaction with the ruthenium surface and form a ruthenium chloride (e.g., RuCh) passivation layer on the ruthenium surface, a ligand such as ACAC or EDTA for ligand- assisted reactive dissolution of the ruthenium chloride passivation layer, and a base or other catalyst to increase the rate of the ligand reaction and continuously etch the ruthenium surface.
• Tire relative kinetic rates of the chlorination reaction and the ligand-assisted dissolution reaction can be adjusted by changing the concentrations of TCCA and the ligand in the slurry solution.
• halogenation kinetics and dissolution kinetics can be independently controlled by adjusting the relative amounts of the halogenation agent and the ligand included within the CMP slurry, so that the rate of halogenation of the ruthenium surface is greater than the rate of dissolution of the halogenated ruthenium surface.
• oxidizer-based etch chemistry lacks this independent control.
• the CMP slurry' described herein includes halogenating agents, but is free from oxide-forming oxidizing agents, such as water or dissolved oxygen.
• the CMP slurry may 7 contain both halogenating agents and oxide-forming oxidizing agents.
• the CMP slurry' described above may further include a predetermined amount of water or dissolved oxygen.
• a ruthenium chloride e.g., RuCh
• RuOxCly species are generally more soluble than the ruthenium chloride passivation layer, the presence of the RuOxCly species on the ruthenium surface increases the material removal rate achieved in the CMP process.
• the CMP slurry described herein may also contain abrasive media, such as silica, alumina, ceria, or other nanoparticles to mechanically grind the ruthenium surface.
• abrasive media such as silica, alumina, ceria, or other nanoparticles to mechanically grind the ruthenium surface. This mechanical grinding raises the local temperature at high points on tire wafer surface. This local heating serves to increase the etch kinetics, which helps to planarize the wafer. Since the ligand exchange reactions used to solubilize RuCh are very temperature sensitive, the local heating created at the high points is very effective at increasing the local etch rate in those areas.
• FIG. 1 illustrates one example of a CMP system 100 that includes a polishing pad 105 mounted on top of a rotating platen 110 and a slurry dispenser 115 for dispensing a slurry 120 over the top of the polishing pad 105. As the platen 110 rotates, the motion of the platen 110 distributes the shiny? 120 over the surface of the polishing pad 105.
• a wafer carrier 125 holds and positions a wafer 130 (e.g., a semiconductor substrate), and applies downward force between the wafer surface and the polishing pad 105.
• Tire wafer carrier 125 can rotate and move radially along the platen 110.
• a pad conditioner 135 is used to maintain pad flatness and surface quality.
• the techniques described herein include an improved slurry chemistry as part of the chemical, reactive portion of chemical -mechanical material removal. As mentioned, FIG. 1 illustrates one example CMP system. It will be recognized by those skilled in the art that the techniques, methods, processes and shiny chemistries described herein may be used with a wide variety of CMP tools and systems and are not limited to that shown in FIG. 1 .
• FIG. 2 illustrates one embodiment of a method that utilizes the techniques described herein for planarizing or removing ruthenium from a surface of a substrate. It will be recognized that the embodiment of FIG. 2 is merely exemplary and additional methods may utilize the techniques described herein. Further, additional processing steps may be added to the method shown in the FIG. 2 as the steps described are not intended to be exclusive. Moreover, the order of the steps is not limited to tlie order shown in the figures as different orders may occur and/or various steps may be performed in combination or at the same time.
• FIG. 2 illustrates one embodiment of a method 200 of removing ruthenium.
• the method 200 may generally begin by positioning a substrate in a chemical -mechanical polishing (CMP) system (in step 210).
• FIG. 1 illustrates one embodiment of a CMP system (or CMP tool) in which the substrate may be positioned in step 210.
• the CMP system 100 may generally include a polishing pad 105 mounted on a rotatable platen 110. such that the polishing pad 105 can be rotated and moved across a surface of the substrate.
• the substrate may include a ruthenium surface.
• the method 200 may include dispensing a slurry over the polishing pad (in step 220).
• the slurry may generally include a solvent, a halogenation agent that halogenates the ruthenium surface to form a halogenated ruthenium surface, a ligand that reacts with the halogenated ruthenium surface to dissolve the halogenated ruthenium surface, and a catalyst that increases a rate of a ligand exchange reaction with the halogenated ruthenium surface.
• the method 200 may include controlling relative amounts of the halogenation agent and the ligand included within the slurry, such that a rate of halogenation of the ruthenium surface is greater than a rate of dissolution of the halogenated ruthenium surface.
• method 200 may include polishing the ruthenium surface using the shiny' until a predetermined amount of ruthenium has been removed (in step 230).
• substrate means and includes a base material or construction upon which materials are formed. It will be appreciated that the substrate may include a single material, a plurality of layers of different materials, a layer or layers having regions of different materials or different structures in them, etc. These materials may include semiconductors, insulators, conductors, or combinations thereof.
• the substrate may be a semiconductor substrate, a base semiconductor layer on a supporting structure, a metal electrode or a semiconductor substrate having one or more layers, structures or regions formed thereon.
• the substrate may be a conventional silicon substrate or other bulk substrate comprising a layer of semi-conductive material.
• bulk substrate means and includes not only silicon wafers, but also silicon-on-insulator (“SOI”) substrates, such as silicon-on-sapphire (“SOS”) substrates and silicon-on-glass (“SOG”) substrates, epitaxial layers of silicon on a base semiconductor foundation, and other semiconductor or optoelectronic materials, such as silicon-germanium, germanium, gallium arsenide, gallium nitride, and indium phosphide.
• SOI silicon-on-insulator
• SOS silicon-on-sapphire
• SOOG silicon-on-glass
• epitaxial layers of silicon on a base semiconductor foundation and other semiconductor or optoelectronic materials, such as silicon-germanium, germanium, gallium arsenide, gallium nitride, and indium phosphide.
• the substrate may be doped or undoped.
• the substrate may include any material portion or structure of a device, particularly a semiconductor or other electronics device, and may, for example, be a base substrate structure, such as a semiconductor substrate or a layer on or overlying a base substrate structure such as a thin film .
• substrate is not intended to be limited to any particular base structure, underlying layer or overlying layer, paterned or unpattemed, but rather, is contemplated to include any such layer or base structure, and any combination of layers and/or base structures.

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