Silica-based slurry for selective polishing of carbon-based films

Abstract

This invention provides a chemical mechanical polishing composition comprising: (a) a silica abrasive, (b) a surfactant, (c) an iron cation, (d) optionally a ligand, and (e) water, wherein the silica abrasive has a negative zeta potential in the chemical mechanical polishing composition. This invention also provides a method for chemically mechanically polishing a substrate, particularly a substrate comprising a carbon-based film, using the said composition.

Description

Background Technology

[0001] In the manufacture of integrated circuits and other electronic devices, multiple layers of conductive, semiconductor, and dielectric materials are deposited onto or removed from a substrate surface. As layers of material are sequentially deposited onto and removed from the substrate, the uppermost surface of the substrate can become non-planar and requires planarization. Planarization, or "polishing," is one method of removing material from the substrate surface to form a generally uniform and flat surface. Planarization is suitable for removing unwanted surface topography and surface defects, such as rough surfaces, agglomerates, lattice damage, scratches, and contaminated layers or materials. Planarization is also suitable for forming features on a substrate by removing excess deposited material used to fill features and provide a uniform surface for subsequent metallization and processing.

[0002] Compositions and methods for planarizing or polishing substrate surfaces are well known in the art. Chemical mechanical planarization or chemical mechanical polishing (CMP) is a common technique for planarizing substrates. CMP utilizes a chemical composition, referred to as a CMP composition or more simply as a polishing composition (also known as a polishing slurry), for the selective removal of material from the substrate. The polishing composition is typically applied to the substrate by contacting the substrate surface with a polishing pad (e.g., a polishing cloth or polishing disc) saturated with the polishing composition. Polishing of the substrate is typically further aided by the chemical activity of the polishing composition and / or the mechanical activity of the abrasive suspended in or incorporated into the polishing composition or the polishing pad (e.g., a fixed abrasive polishing pad).

[0003] As the size of integrated circuits (ICs) shrinks and the number of ICs on a wafer increases, the components constituting the circuit must be placed closer together to fit within the limited space available on a typical wafer. Effective isolation between circuits is crucial for ensuring optimal semiconductor performance. To this end, shallow trenches are etched into the semiconductor substrate and filled with insulating material to isolate the active region of the IC. More specifically, shallow trench isolation (STI) is a method in which a silicon nitride or titanium nitride layer is formed on a silicon substrate, shallow trenches are formed by etching or photolithography, and a dielectric layer is deposited to fill the trenches. Due to the varying depth of the trenches formed in this manner, it is often necessary to deposit excess dielectric material on top of the substrate to ensure complete filling of all trenches. This dielectric material (e.g., a carbon-based film) conforms to the underlying topography of the substrate. This excess dielectric material is typically removed by a CMP (chemical mechanical polishing) method, which also provides a flat surface for further processing.

[0004] Polishing compositions can be characterized by their polishing rate (i.e., removal rate) and their planarization efficiency. The polishing rate refers to the rate at which material is removed from the substrate surface and is typically expressed in units of length (thickness) per unit time (e.g., angstroms). / minute). Planarization efficiency is related to the reduction in step height relative to the amount of material removed from the substrate. Specifically, the polished surface (e.g., a polishing pad) first contacts the "high point" of the surface and material must be removed to form a flat surface. Methods that result in achieving a flat surface by removing less material are considered more efficient than methods that require removing more material to achieve flatness.

[0005] Typically, the removal rate of carbon-based films can be rate-limiting for the dielectric polishing step in the STI process, and therefore a high removal rate of the carbon-based film is desirable to increase device throughput. However, if the blanket removal rate is too fast, over-polishing of the oxides in the exposed trenches leads to trench erosion and increased device defects.

[0006] There is still a need for compositions and methods for the chemical-mechanical polishing of carbon-based films, which would provide useful removal rates while also providing improved planarization efficiency. This invention provides such polishing compositions and methods. These and other advantages, and additional inventive features of the invention will become clear from the description of the invention provided herein. Summary of the Invention

[0007] The present invention provides a chemical mechanical polishing composition comprising, substantially comprising, or comprising: (a) a silica abrasive; (b) a surfactant; (c) an iron cation; (d) optionally a ligand; and (e) water, wherein the silica abrasive has a negative zeta potential in the chemical mechanical polishing composition.

[0008] The present invention further provides a method for chemically and mechanically polishing a substrate, comprising: (i) providing a substrate, (ii) providing a polishing pad, (iii) providing a chemically and mechanically polishing composition comprising: (a) a silica abrasive; (b) a surfactant; (c) an iron cation; (d) optionally a ligand; and (e) water, wherein the silica abrasive has a negative zeta potential in the chemically and mechanically polishing composition, (iv) contacting the substrate with the polishing pad and the chemically and mechanically polishing composition, and (v) moving the polishing pad and the chemically and mechanically polishing composition relative to the substrate to abrade at least a portion of the substrate to polish the substrate. Detailed Implementation

[0009] The present invention provides a chemical mechanical polishing composition comprising: (a) a silica abrasive; (b) a surfactant; (c) an iron cation; (d) optionally a ligand; and (e) water, wherein the silica abrasive has a negative zeta potential in the chemical mechanical polishing composition.

[0010] The polishing composition comprises a silica abrasive. As used herein, the terms “silica abrasive,” “silica abrasive particles,” “silica particles,” and “abrasive particles” are used interchangeably and can refer to any silica particles (e.g., colloidal silica particles). The silica particles (e.g., colloidal silica particles) may be modified (e.g., surface-modified) or unmodified and have a negative or positive Bunsen zeta potential. As used herein, the phrase “Bunsen zeta potential” refers to the zeta potential of the silica abrasive before it is added to the polishing composition. For example, the Bunsen zeta potential can refer to the zeta potential of the silica abrasive before it is added to the polishing composition, as measured, for example, in a storage solution or aqueous solution. Those skilled in the art will be able to determine whether the silica abrasive has a negative or positive Bunsen zeta potential before it is added to the polishing composition. The charge on dispersed particles such as silica abrasives (e.g., colloidal silica particles) is commonly referred to as the zeta potential (or zeta potential). The zeta potential of a particle is the potential difference between the charge of the ions surrounding the particle and the charge of the bulk solution of the composition in which it is measured (e.g., a liquid carrier and any other components dissolved therein). This zeta potential typically depends on the pH of the aqueous medium. For a given polishing composition, the isoelectric point of the particles is defined as the pH at which the zeta potential is zero. As the pH increases or decreases away from this isoelectric point, the surface charge (and therefore the zeta potential) decreases or increases accordingly (to negative or positive zeta potential values). The Bunsen zeta potential and zeta potential of the polishing composition can be obtained using a DT-1202 acoustic and electroacoustic spectrometer, commercially available from Dispersion Technologies, Inc. (Bedford Hills, NY). As used herein, the phrase "negative zeta potential" refers to a silica abrasive that exhibits a negative surface charge when measured in the polishing composition. As used herein, the phrase “positive zeta potential” refers to a silicon oxide abrasive that exhibits a positive surface charge when measured in a polishing composition.

[0011] Silica abrasives in chemical mechanical polishing compositions possess a negative zeta potential. Without wishing to be bound by any particular theory, it is believed that the negative zeta potential of the silica abrasive in the chemical mechanical polishing composition has a favorable interaction with the cationic properties of the surface of the carbon-based film, which contributes to the advantageous polishing characteristics described herein. In some embodiments, the silica abrasive has a zeta potential less than 0 mV when measured in the polishing composition; that is, the silica abrasive has a negative zeta potential when measured in the polishing composition. For example, the silica abrasive may have a zeta potential of -10 mV or less in the chemical mechanical polishing composition, -20 mV or less in the chemical mechanical polishing composition, -30 mV or less in the chemical mechanical polishing composition, or -40 mV or less in the chemical mechanical polishing composition. In some embodiments, the silica abrasive has a negative z-potential of about 0 mV to about -60 mV, for example, about -10 mV to about -60 mV, about -10 mV to about -50 mV, about -10 mV to about -40 mV, about -20 mV to about -60 mV, about -20 mV to about -50 mV, about -20 mV to about -40 mV, about -30 mV to about -40 mV, or about -20 mV to about -30 mV.

[0012] Silica abrasives (e.g., colloidal silica particles) may be modified (e.g., surface-modified) or unmodified and have a negative or positive Bunsen zeta potential. Therefore, the silica abrasive (e.g., colloidal silica particles) may have a positive or negative zeta potential before being added to the chemical mechanical polishing composition. For example, the silica particles (e.g., colloidal silica particles) may have a Bunsen zeta potential of less than 0 mV (e.g., -5 mV or lower) before being added to the chemical mechanical polishing composition. Alternatively, the silica particles (e.g., colloidal silica particles) may have a Bunsen zeta potential of 0 mV or greater (e.g., 5 mV or greater) before being added to the chemical mechanical polishing composition. When added to the chemical mechanical polishing composition of the present invention described herein, the silica abrasive having a negative Bunsen zeta potential maintains the negative zeta potential (e.g., by (i) using a cationic surfactant that cannot convert the negative zeta potential to a positive zeta potential or (ii) using an anionic surfactant that maintains the negative zeta potential). Alternatively, when added to the chemical mechanical polishing composition of the present invention described herein, a silica abrasive having a positive Bunsen zeta potential can be desirablely converted into a silica abrasive having a negative zeta potential (e.g., by using an anionic surfactant that can convert the positive zeta potential into a negative zeta potential).

[0013] Silica particles (e.g., colloidal silica particles) and charged silica particles (e.g., colloidal silica particles) can be prepared by a variety of methods, some of which are commercially available and known. Useful silica particles include precipitated or condensed silica, which can be prepared using known methods, such as by a method known as a "sol-gel" process or by silicate ion exchange. Condensed silica particles are typically prepared by condensing Si(OH)₄ to form generally spherical (e.g., spherical, oval, or elliptical) particles. The precursor Si(OH)₄ can be obtained, for example, by hydrolyzing a high-purity alkoxysilane or by acidification of an aqueous silicate solution. U.S. Patent No. 5,230,833 describes a method for preparing colloidal silica particles in solution.

[0014] In some embodiments, the silica abrasive is colloidal silica. As known to those skilled in the art, colloidal silica is a suspension of fine, amorphous, non-porous, and generally spherical particles in a liquid phase. The colloidal silica may be in the form of condensed or precipitated silica particles. In some embodiments, the silica is in the form of wet-process silica particles. The particles (e.g., colloidal silica) may have any suitable average size (i.e., average particle diameter). If the average abrasive particle size is too small, the polishing composition may not exhibit a sufficient removal rate. Conversely, if the average abrasive particle size is too large, the polishing composition may exhibit undesirable polishing performance, such as, for example, poor substrate defects.

[0015] Therefore, the silica abrasive (e.g., silica particles or colloidal silica particles) may have an average particle size of about 10 nm or larger, such as about 15 nm or larger, about 20 nm or larger, about 25 nm or larger, about 30 nm or larger, about 35 nm or larger, about 40 nm or larger, about 45 nm or larger, or about 50 nm or larger. Alternatively, the silica abrasive may have an average particle size of about 200 nm or smaller, such as about 175 nm or smaller, about 150 nm or smaller, about 125 nm or smaller, about 100 nm or smaller, about 75 nm or smaller, about 50 nm or smaller, or about 40 nm or smaller. Therefore, the silica abrasive may have an average particle size defined by any two of the foregoing endpoints.

[0016] For example, silica abrasives (e.g., silica particles or colloidal silica particles) may have an average particle size of about 10 nm to about 200 nm, about 20 nm to about 200 nm, about 20 nm to about 175 nm, about 20 nm to about 150 nm, about 25 nm to about 125 nm, about 25 nm to about 100 nm, about 30 nm to about 100 nm, about 30 nm to about 75 nm, about 30 nm to about 40 nm, or about 50 nm to about 100 nm. For non-spherical silica abrasive particles, the particle size is the diameter of the smallest sphere surrounding the particle. The particle size of the abrasive can be measured using any suitable technique, such as laser diffraction. Suitable particle size measurement instruments are available, for example, from Malvern Instruments (Malvern, UK).

[0017] Silica abrasives (e.g., silica particles or colloidal silica particles) are preferably colloidally stable in the polishing composition. The term colloid refers to a suspension of particles in a liquid carrier (e.g., water). Colloidal stability refers to the maintenance of this suspension over time. In the context of this invention, when the abrasive is placed in a 100 mL graduated cylinder and allowed to stand for 2 hours, the abrasive is considered colloidally stable if the difference between the particle concentration ([B], in g / mL) in the bottom 50 mL of the graduated cylinder and the particle concentration ([T], in g / mL) in the top 50 mL of the graduated cylinder, divided by the initial particle concentration ([C], in g / mL) in the abrasive composition, is less than or equal to 0.5 (i.e., {[B]-[T]} / [C]≤0.5). More preferably, the value of [B]-[T] / [C] is less than or equal to 0.3, and most preferably less than or equal to 0.1.

[0018] Silica abrasives can be present in the polishing composition in any suitable amount. If the polishing composition of the present invention contains too little abrasive, the composition may not exhibit an adequate removal rate. Conversely, if the polishing composition contains too much abrasive, the polishing composition may exhibit undesirable polishing performance and / or may be cost-inefficient and / or lack stability. The polishing composition may contain about 10% by weight or less of silica abrasive, for example, about 9% by weight or less, about 8% by weight or less, about 7% by weight or less, about 6% by weight or less, about 5% by weight or less, about 4% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.9% by weight or less, about 0.8% by weight or less, about 0.7% by weight or less, about 0.6% by weight or less, or about 0.5% by weight or less of silica abrasive. Alternatively, the polishing composition may contain about 0.001% by weight or more of silicon oxide abrasive, for example, about 0.005% by weight or more, about 0.01% by weight or more, 0.05% by weight or more, about 0.1% by weight or more, about 0.2% by weight or more, about 0.3% by weight or more, about 0.4% by weight or more, about 0.5% by weight or more, or about 1% by weight or more of silicon oxide abrasive. Therefore, where appropriate, the polishing composition may contain an amount of silicon oxide abrasive defined by any of the foregoing endpoints.

[0019] For example, in some embodiments, the silica abrasive may be present in the polishing composition in an amount from about 0.001 wt% to about 10 wt%, such as about 0.001 wt% to about 8 wt%, about 0.001 wt% to about 6 wt%, about 0.001 wt% to about 5 wt%, about 0.001 wt% to about 4 wt%, about 0.001 wt% to about 2 wt%, about 0.001 wt% to about 1 wt%, about 0.01 wt% to about 10 wt%, about 0.01 wt% to about 8 wt%, about 0.01 wt% to about 6 wt%, about 0.01 wt% to about 5 wt%, about 0.01 wt% to about 4 wt%, about 0.01 wt% to about 2 wt%, about 0.01 wt% to about 1 wt%, about 0.05 wt% to about 10 wt%, about 0.05 wt% to about 8 wt%, about 0.05 wt% to about 6 wt%, about 0.05 wt% to about 10 wt%, about 0.05 wt% to about 8 wt%, about 0.05 wt% to about 6 wt%, about 0.05 wt% to about 10 wt%. From approximately 5% to 5% by weight, from approximately 0.05% by weight to approximately 4% by weight, from approximately 0.05% by weight to approximately 2% by weight, from approximately 0.05% by weight to approximately 1% by weight, from approximately 0.1% by weight to approximately 10% by weight, from approximately 0.1% by weight to approximately 8% by weight, from approximately 0.1% by weight to approximately 6% by weight, from approximately 0.1% by weight to approximately 5% by weight, from approximately 0.1% by weight to approximately 4% by weight, from approximately 0.1% by weight to approximately 2% by weight, from approximately 0.1% by weight to approximately 1% by weight, from approximately 0.5% by weight to approximately 10% by weight, from approximately 0.5% by weight to approximately 8% by weight, from approximately 0.5% by weight to approximately 5% by weight, from approximately 0.5% by weight to approximately 4% by weight, from approximately 0.5% by weight to approximately 2% by weight, from approximately 0.5% by weight to approximately 1% by weight, from approximately 1% by weight to approximately 10% by weight, from approximately 1% by weight to approximately 8% by weight, from approximately 1% by weight to approximately 6% by weight, from approximately 1% by weight to approximately 5% by weight, from approximately 1% by weight to approximately 4% by weight, or from approximately 1% by weight to approximately 2% by weight.

[0020] The polishing composition contains an iron cation. This iron cation may be present in the form of ferric ions (i.e., iron III) or ferrous ions (i.e., iron II), and may be added to the composition in the form of any suitable iron-containing salt. For example, the iron cation may be generated by adding the following to the polishing composition: ferric nitrate, ferric sulfate, iron halides (including fluorides, chlorides, bromides, and iodides, as well as perchlorates, perbromates, and periodates), and organoiron compounds such as iron acetates, acetylacetones, citrates, gluconates, malonates, oxalates, phthalates, succinates, and combinations thereof.

[0021] The polishing composition may contain any suitable amount of iron cations. The polishing composition may contain about 0.01 ppm or more, for example, 0.1 ppm or more, about 0.5 ppm or more, about 1 ppm or more, about 5 ppm or more, about 10 ppm or more, or about 20 ppm or more of iron cations. Alternatively, the polishing composition may contain about 100 ppm or less, for example, about 80 ppm or less, about 60 ppm or less, or about 40 ppm or less of iron cations. Therefore, the polishing composition may contain the amount of iron cations defined by any of the foregoing endpoints. For example, the polishing composition may contain iron cations at concentrations of about 0.01 ppm to about 100 ppm, such as about 0.01 ppm to about 80 ppm, about 0.01 ppm to about 60 ppm, about 0.01 ppm to about 40 ppm, about 0.1 ppm to about 100 ppm, about 0.1 ppm to about 80 ppm, about 0.1 ppm to about 60 ppm, about 0.1 ppm to about 40 ppm, about 1 ppm to about 100 ppm, about 1 ppm to about 80 ppm, about 1 ppm to about 60 ppm, about 1 ppm to about 40 ppm, about 10 ppm to about 100 ppm, about 10 ppm to about 80 ppm, about 10 ppm to about 60 ppm, or about 10 ppm to about 40 ppm. Without wishing to be bound by any particular theory, it is believed that increasing the iron concentration results in a higher removal rate for carbon-based films. However, it is also believed that a higher iron concentration can be associated with a variety of defect problems when polishing commercially available carbon-based films.

[0022] The polishing composition contains a surfactant. This surfactant can be a cationic or anionic surfactant. Generally, when the silica abrasive has a negative Bunsen zeta potential, the surfactant is either a cationic or anionic surfactant, and when the silica abrasive has a positive Bunsen zeta potential, the surfactant is anionic. As described herein, the silica abrasive has a negative zeta potential in the chemical mechanical polishing composition (i.e., when measured in the chemical mechanical polishing composition). Therefore, any suitable combination of silica particles and surfactant can be used, as long as the resulting composition contains a silica abrasive with a negative zeta potential. In some embodiments, the surfactant is a cationic surfactant when the silica abrasive has a negative Bunsen zeta potential, and an anionic surfactant when the silica abrasive has a positive Bunsen zeta potential, such that the resulting composition contains a silica abrasive with a negative zeta potential. In a preferred embodiment, the silica abrasive has a positive Bunsen zeta potential and the surfactant is anionic, such that the silica abrasive has a negative zeta potential when measured in the chemical mechanical polishing composition.

[0023] In some embodiments, the chemical mechanical polishing composition comprises a silica abrasive having a negative Bunsen zeta potential and a cationic surfactant, such that the silica abrasive has a negative zeta potential when measured in the chemical mechanical polishing composition.

[0024] In some embodiments, the chemical mechanical polishing composition comprises a silica abrasive having a negative Bunsen zeta potential and an anionic surfactant, such that the silica abrasive has a negative zeta potential when measured in the chemical mechanical polishing composition.

[0025] In some embodiments, the chemical mechanical polishing composition comprises a silica abrasive having a positive Bunsen zeta potential and an anionic surfactant, such that the silica abrasive has a negative zeta potential when measured in the chemical mechanical polishing composition.

[0026] In some embodiments, the chemical mechanical polishing composition comprises a silica abrasive having a Bunsen zeta potential with the opposite charge to that of the surfactant, i.e., a silica abrasive having a positive Bunsen zeta potential and an anionic surfactant, or a silica abrasive having a negative Bunsen zeta potential and a cationic surfactant.

[0027] In some embodiments, the surfactant is a cationic surfactant. The cationic surfactant can be any suitable cationic surfactant, many of which are known in the art. In some embodiments, the cationic surfactant comprises a quaternary ammonium salt. Exemplary cationic surfactants include (but are not limited to) N,N,N',N',N'-pentamethyl-N-tallow alkyl-1,3-propane diammonium chloride, (oxydi-2,1-ethanediyl)bis(cocoyl)dimethylammonium dichloride, 3-methacryloylaminopropyl-trimethyl-ammonium chloride (“MAPTAC”), 3-acryloylaminopropyl-trimethyl-ammonium chloride (“APTAC”), diallyl dimethyl ammonium chloride (“DADMAC”), 2-(acryloyloxy)-N,N,N-trimethylethyl ammonium chloride (2-(acryloyloxy)-N,N,N- trimethylethanaminium chloride (“DMAEA.MCQ”), 2-(methacryloyloxy)-N,N,N-trimethylethanaminium chloride (“DMAEM.MCQ”), N,N-dimethylaminoethyl acrylate benzyl chloride (“DMAEA.BCQ”), N,N-dimethylaminoethyl methacrylate benzyl chloride (“DMAEM.BCQ”), and combinations thereof.

[0028] In some embodiments, the surfactant is an anionic surfactant. The anionic surfactant can be any suitable anionic surfactant, many of which are known in the art. In some embodiments, the anionic surfactant is selected from alkyl sulfonic acids, alkyl sulfonates, aryl sulfonic acids, aryl sulfonates, alkyl aryl sulfonic acids, alkyl aryl sulfonates, and combinations thereof. In some embodiments, the anionic surfactant is selected from saturated or unsaturated C6-C... 40 Alkyl sulfonates, saturated or unsaturated C6-C 40 Alkyl sulfonic acids, saturated or unsaturated C6-C 40 Alkylbenzene sulfonates, saturated or unsaturated C6-C 40 Alkylbenzene sulfonic acids and combinations thereof. Exemplary anionic surfactants include (but are not limited to) CALSOFT, commercially available from Pilot Chemical Corporation, West Chester, OH. TM Surfactants (e.g., CALSOFT) TM LPS-99-dodecylbenzenesulfonic acid) or ZETASPERSE available from Air Products, Allentown, PA TM Surfactants (e.g., ZETASPERSE) TM Z2300-Ethoxylated C6-C 12 Alcohol (CAS 68439-45-2) and C 10 -C 14 (A mixture of alkyl aryl sulfonates).

[0029] In some embodiments, the cationic and / or anionic surfactants comprise an alkyl chain of about six or more carbon atoms. For example, the cationic and / or anionic surfactants may comprise an alkyl chain of about eight carbon atoms, such as about ten carbon atoms, about twelve carbon atoms, about fourteen carbon atoms, or about sixteen carbon atoms. Without wishing to be bound by any particular theory, surfactants having an alkyl chain of about six carbon atoms (e.g., about twelve carbon atoms) are believed to provide the desired amount of wettability (i.e., lubrication) for the chemimechanical polishing composition.

[0030] The polishing composition may contain any suitable amount of surfactant. The polishing composition may contain about 10 ppm or more, for example, about 20 ppm or more, about 50 ppm or more, about 100 ppm or more, about 200 ppm or more, about 300 ppm or more, or about 500 ppm or more of surfactant. Alternatively, the polishing composition may contain about 10,000 ppm or less, for example, about 8,000 ppm or less, about 6,000 ppm or less, about 5,000 ppm or less, about 4,000 ppm or less, or about 3,000 ppm or less of surfactant. Therefore, the polishing composition may contain the amount of surfactant defined by any two of the foregoing endpoints. For example, the polishing composition may contain a surfactant of about 10 ppm to about 10,000 ppm, such as about 10 ppm to about 8,000 ppm, about 10 ppm to about 6,000 ppm, about 10 ppm to about 5,000 ppm, about 10 ppm to about 4,000 ppm, about 10 ppm to about 3,000 ppm, about 50 ppm to about 10,000 ppm, about 50 ppm to about 8,000 ppm, about 50 ppm to about 6,000 ppm, about 50 ppm to about 5,000 ppm, about 50 ppm to about 4,000 ppm, about 50 ppm to about 3,000 ppm, about 10 ppm to about 10,000 ppm, about 100 ppm to about 8,000 ppm, about 100 ppm to about 6,000 ppm, about 100 ppm to about 5,000 ppm, about 100 ppm to about 4,000 ppm, or about 100 ppm to about 3,000 ppm.

[0031] The polishing composition optionally includes a ligand (e.g., a ligand of an iron cation). Thus, in some embodiments, the polishing composition includes a ligand, and in other embodiments, the composition does not contain a ligand. In a preferred embodiment, the polishing composition includes a ligand (e.g., a ligand of an iron cation). The ligand can be any suitable ligand, many of which are known in the art. In some embodiments, the ligand includes an olefin moiety, an alkyne moiety, a diacid moiety, an alcohol moiety, or a combination thereof. For example, the ligand can be any compound comprising (e.g., an organic compound): an olefin moiety; an alkyne moiety; a diacid moiety; an alcohol moiety; an olefin moiety and a diacid moiety; an olefin moiety and an alcohol moiety; an olefin moiety, a diacid moiety and an alcohol moiety; an alkyne moiety and a diacid moiety; an alkyne moiety, a diacid moiety and an alcohol moiety; or an olefin moiety, an alkyne moiety, a diacid moiety and an alcohol moiety. In some embodiments, the ligand includes: an olefin moiety and a diacid moiety; or an alkyne moiety and an alcohol moiety. Exemplary ligands include (but are not limited to) succinic acid, maleic acid, malonic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, tartaric acid, 3,5-dimethyl-1-hexyn-3-ol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol ethoxylate, 2,5-dimethyl-3-hexyn-2,5-diol, 3-methyl-1-pentyn-3-ol, and combinations thereof.

[0032] The polishing composition may contain any suitable amount of ligand (when present). When the ligand is present, the polishing composition may contain about 10 ppm or more, for example, about 15 ppm or more, about 20 ppm or more, about 25 ppm or more, about 30 ppm or more, about 35 ppm or more, or about 40 ppm or more of the ligand. Alternatively, the polishing composition may contain about 1000 ppm or less, for example, about 800 ppm or less, about 600 ppm or less, about 400 ppm or less, about 200 ppm or less, about 100 ppm or less, about 80 ppm or less, about 60 ppm or less, or about 40 ppm or less of the ligand. Thus, the polishing composition may contain an amount of ligand defined by any two of the foregoing endpoints. For example, the polishing composition may contain ligands of about 10 ppm to about 1000 ppm, such as surfactants of about 10 ppm to about 800 ppm, about 10 ppm to about 600 ppm, about 10 ppm to about 400 ppm, about 10 ppm to about 200 ppm, about 10 ppm to about 100 ppm, about 10 ppm to about 80 ppm, about 10 ppm to about 60 ppm, about 10 ppm to about 40 ppm, about 20 ppm to about 1000 ppm, about 20 ppm to about 800 ppm, about 20 ppm to about 600 ppm, about 20 ppm to about 400 ppm, about 20 ppm to about 200 ppm, about 20 ppm to about 100 ppm, about 20 ppm to about 80 ppm, about 20 ppm to about 60 ppm, or about 20 ppm to about 40 ppm.

[0033] The chemical mechanical polishing composition may contain one or more compounds capable of adjusting (i.e., regulating) the pH of the polishing composition (i.e., pH adjusting compounds). The pH of the polishing composition may be adjusted using any suitable pH adjusting compound. Desiredly, the pH adjusting compound is water-soluble and compatible with the other components of the polishing composition. Typically, the chemical mechanical polishing composition has a pH of about 1 to about 7 at the point of use (e.g., about 1 to about 6, about 1 to about 5, about 2 to about 7, about 2 to about 6, about 2 to about 5, about 3 to about 6, or about 1 to about 4). Preferably, the chemical mechanical polishing composition has a pH of about 1 to about 4 at the point of use.

[0034] Compounds that can adjust and buffer pH can be selected from: ammonium salts, alkali metal salts, carboxylic acids, alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, borates, and mixtures thereof.

[0035] The chemical mechanical polishing composition optionally further comprises one or more additives. Illustrative additives include conditioners, acids (e.g., sulfonic acids), complexing agents, chelating agents, biocides, scale inhibitors, and dispersants.

[0036] When present, the biocide can be any suitable biocide and can be present in any suitable amount in the polishing composition. A suitable biocide is an isothiazolinone biocide. Typically, the polishing composition contains about 1 ppm to about 50 ppm of biocide, preferably about 10 ppm to about 20 ppm of biocide.

[0037] The polishing composition can be produced by any suitable technique, many of which are known to those skilled in the art. The polishing composition can be prepared by batch or continuous methods. Generally, the polishing composition is prepared by combining its components. As used herein, the term "component" includes individual components (e.g., silica abrasives, surfactants, iron cations, optional ligands, optional pH adjusters, and / or any optional additives) and any combination of components (e.g., silica abrasives, surfactants, iron cations, optional ligands, optional pH adjusters, and / or any optional additives, etc.).

[0038] For example, a polishing composition may be prepared by: (i) providing all or part of a liquid carrier, (ii) dispersing silica abrasives, surfactants, iron cations, optional ligands, optional pH adjusters and / or any optional additives using any suitable method for preparing such a dispersion, (iii) adjusting the pH of the dispersion where appropriate, and (iv) optionally adding suitable amounts of any other optional components and / or additives to the mixture.

[0039] Alternatively, the polishing composition may be prepared by: (i) providing one or more components (e.g., surfactants, iron cations, optional ligands, optional pH adjusters, and / or any optional additives) in a silica abrasive slurry; (ii) providing one or more components (e.g., liquid carriers, surfactants, iron cations, optional ligands, optional pH adjusters, and / or any optional additives) in an additive solution; (iii) combining the silica abrasive slurry and the additive solution to form a mixture; (iv) optionally adding a suitable amount of any other optional additives to the mixture; and (v) adjusting the pH of the mixture, where appropriate.

[0040] The polishing composition can be supplied as a single-package system comprising silica abrasive, surfactant, iron cation, optional ligand, optional pH adjuster and / or any optional additive, and water. Alternatively, the polishing composition of the present invention can be supplied as a two-package system comprising a silica abrasive slurry in a first package and an additive solution in a second package, wherein the silica abrasive slurry is substantially composed of silica abrasive and water, or substantially composed of silica abrasive and water, and wherein the additive solution is substantially composed of surfactant, iron cation, optional ligand, optional pH adjuster and / or any optional additive, or substantially composed of surfactant, iron cation, optional ligand, optional pH adjuster and / or any optional additive. This two-package system allows for adjustment of the polishing composition properties by varying the blending ratio of the two packages (i.e., the silica abrasive slurry and the additive solution).

[0041] Various methods can be used to utilize such a two-package polishing system. For example, the silica abrasive slurry and additive solution can be delivered to the polishing table via different pipes connected and linked at the outlet of the supply line. The silica abrasive slurry and additive solution can be mixed shortly before polishing or just before polishing, or can be supplied to the polishing table simultaneously. Furthermore, when mixing the two packages, deionized water can be added as desired to adjust the polishing composition and the resulting substrate polishing characteristics.

[0042] Similarly, in conjunction with the present invention, three, four or more packaging systems can be used, wherein each of the plurality of containers contains, at different concentrations, different components, one or more optional components, and / or one or more of the same components of the chemimechanical polishing composition of the present invention.

[0043] To mix components contained in two or more storage devices to produce a polishing composition at or near a point of use, the storage devices typically have one or more flow paths leading from each storage device to the point of use (e.g., a platform, polishing pad, or substrate surface) of the polishing composition. As used herein, the term "point of use" refers to the site where the polishing composition is applied to the substrate surface (e.g., the polishing pad or the substrate surface itself). The term "flow path" refers to the path from a separate storage container to the point of use of the component stored therein. The flow path may lead directly to the point of use on its own, or two or more of the flow paths may be combined at any point to form a single flow path leading to the point of use. Furthermore, any of the flow paths (e.g., a single flow path or a combined flow path) may first lead to one or more other devices (e.g., a pumping device, a measuring device, a mixing device, etc.) before reaching the point of use of the component.

[0044] The components of the polishing composition may be delivered independently to the point of use (e.g., delivered to the substrate surface during the polishing process, followed by mixing of the components), or one or more of the components may be combined before delivery to the point of use, for example, shortly before delivery to the point of use or just before delivery to the point of use. If the components are combined about 5 minutes or less before being added to the platform in mixed form (e.g., about 4 minutes or less, about 3 minutes or less, about 2 minutes or less, about 1 minute or less, about 45 seconds or less, about 30 seconds or less, about 10 seconds or less before being added to the platform in mixed form), or simultaneously delivered to the point of use (e.g., combined at the dispenser), then the components are "combined just before delivery to the point of use". If the components are combined within 5 m of the point of use (e.g., within 1 m of the point of use or even within 10 cm of the point of use (e.g., within 1 cm of the point of use)), then the components are also "combined just before delivery to the point of use".

[0045] When two or more of the components of a polishing composition combine before reaching the point of use, the components can be combined in a flow path and delivered to the point of use without the use of a mixing device. Alternatively, one or more of the flow paths can lead to a mixing device to facilitate the combination of the two or more components. Any suitable mixing device can be used. For example, the mixing device can be a nozzle or jet (e.g., a high-pressure nozzle or jet) through which two or more of the components flow. Alternatively, the mixing device can be a container-type mixing device comprising one or more inlets and at least one outlet, through which two or more components of the polishing slurry are introduced into the mixer, and the mixed components exit the mixer through the outlet to be delivered directly or via other elements of the device (e.g., via one or more flow paths) to the point of use. Furthermore, the mixing device can comprise more than one chamber, each chamber having at least one inlet and at least one outlet, in which two or more components are combined. If a container-type mixing device is used, the mixing device preferably includes a mixing mechanism to further facilitate the combination of components. The mixing mechanism is generally known in the art and includes agitators, mixers, agitators, impellers, gas distributor systems, vibrators, etc.

[0046] The polishing composition may also be provided as a concentrate intended to be diluted with an appropriate amount of water before use. In such an embodiment, the polishing composition concentrate contains the components of the polishing composition in amounts such that when the concentrate is diluted with an appropriate amount of water, each component of the polishing composition will be present in the polishing composition in an amount within the appropriate range listed above for each component. For example, silica abrasives, surfactants, iron cations, optional ligands, optional pH adjusters, and / or any optional additives may each be present in the concentrate in an amount approximately twice (e.g., approximately three times, approximately four times, or approximately five times) the concentrations listed above for each component, such that when the concentrate is diluted with equal volumes of water (e.g., two, three, or four equal volumes of water, respectively), each component will be present in the polishing composition in an amount within the range listed above for each component. Furthermore, as will be understood by those skilled in the art, the concentrate may contain an appropriate fraction of water present in the final polishing composition to ensure that the silica abrasive, surfactant, iron cation, optional ligand, optional pH adjuster and / or any optional additive are at least partially or completely dissolved in the concentrate.

[0047] The present invention further provides a method for chemically and mechanically polishing a substrate, comprising: (i) providing a substrate, (ii) providing a polishing pad, (iii) providing a chemically and mechanically polishing composition comprising: (a) a silica abrasive; (b) a surfactant; (c) an iron cation; (d) optionally a ligand; and (e) water, wherein the silica abrasive has a negative zeta potential in the chemically and mechanically polishing composition, (iv) contacting the substrate with the polishing pad and the chemically and mechanically polishing composition, and (v) moving the polishing pad and the chemically and mechanically polishing composition relative to the substrate to abrade at least a portion of the substrate to polish the substrate.

[0048] This chemical mechanical polishing composition can be used to polish any suitable substrate and is particularly suitable for polishing substrates comprising at least one layer (typically a surface layer) of a low-dielectric material. Suitable substrates include wafers used in the semiconductor industry. These wafers typically comprise or are composed of, for example, metals, metal oxides, metal nitrides, metal composites, metal alloys, low-dielectric materials, or combinations thereof. The method of the present invention is particularly suitable for polishing substrates comprising carbon-based films (e.g., carbon hard mask materials). In some embodiments, the substrate comprises a carbon-based film, wherein at least a portion of the carbon-based film is removed at a rate... The substrate is polished by grinding.

[0049] In some embodiments, the substrate comprises a carbon-based film. The carbon-based film can be any suitable material containing carbon (e.g., a low-dielectric material), many of which are known in the art. In some embodiments, the carbon-based film comprises more than about 50% by weight of carbon, for example, more than about 60% by weight, more than about 70% by weight, more than about 80% by weight, more than about 90% by weight, or more than about 95% by weight of carbon. The carbon-based film can have any suitable phase. For example, the carbon-based film can be amorphous, crystalline, or a combination thereof. In some embodiments, the carbon-based film is amorphous. Illustrative carbon-based films are described in Weigand et al. (“Evaluating spin-on carbon materials at low temperatures for high wiggling resistance.” Advanced Etch Technology for Nanopatterning II., Vol. 8685, International Society for Optics and Photonics, 2013) and Kim et al. (“Study on the etching characteristics of amorphous carbon layer in oxygen plasma with carbonyl sulfide.” Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, (2013), 31.2:021301, pp. 1–7).

[0050] In some embodiments, the substrate comprises a carbon-based film, and at least a portion of the carbon-based film is removed at a rate... The substrate is polished by grinding. When polishing a substrate containing a carbon-based film according to the method of the present invention, the chemical mechanical polishing composition of the present invention desirously exhibits a high removal rate. For example, when polishing a substrate containing a carbon-based film according to an embodiment of the present invention, the polishing composition desirously exhibits approximately Or higher, for example, about or higher, approximately or higher, approximately or higher, approximately or higher, approximately or higher, approximately or higher, approximately or higher, approximately or higher, approximately or higher, approximately or higher, approximately Or higher, or approximately Or a higher removal rate for carbon-based membranes.

[0051] In some embodiments, the substrate further comprises silicon oxide, silicon nitride, polysilicon, titanium nitride, or a combination thereof, and at least a portion of the silicon oxide, silicon nitride, polysilicon, or titanium nitride is removed at a rate of The substrate is polished by grinding. In embodiments where the substrate further comprises silicon oxide, silicon nitride, polycrystalline silicon, titanium nitride, or a combination thereof, the removal rate of the carbon-based film is... Greater than the removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride For example, the removal rate of this carbon-based membrane The removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride can be specified. At least 10 times the removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride. At least 20 times, or the removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride. At least 40 times.

[0052] In embodiments where the substrate further comprises silicon oxide, the silicon oxide can be any suitable silicon oxide, many of which are known in the art. Suitable types of silicon oxides include (but are not limited to) borosilicate glass (BPSG), tetraethyl orthosilicate (TEOS), plasma-enhanced tetraethyl orthosilicate (PETEOS), thermal oxides, undoped silicate glasses, and high-density plasma (HDP) oxides. When polishing a substrate containing silicon oxide according to the method of the invention, the chemical mechanical polishing composition of the invention desiccates a low removal rate. For example, when polishing a substrate containing silicon oxide according to an embodiment of the invention, the polishing composition desiccates approximately Or lower, for example, about or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately Or lower, or about Or even lower silicon oxide removal rates. In some embodiments, the polishing composition exhibits silicon oxide removal rates that are too low to be detected.

[0053] In embodiments where the substrate further comprises polycrystalline silicon, the polycrystalline silicon can be any suitable polycrystalline silicon, many of which are known in the art. The polycrystalline silicon can have any suitable phase and can be amorphous, crystalline, or a combination thereof. When polishing a substrate containing polycrystalline silicon according to the method of the invention, the chemical mechanical polishing composition of the invention desiccates a low removal rate. For example, when polishing a substrate containing polycrystalline silicon according to an embodiment of the invention, the polishing composition desiccates approximately Or lower, for example, about or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately Or lower, or about Or even lower polysilicon removal rates. In some embodiments, the polishing composition exhibits polysilicon removal rates that are too low to be detected.

[0054] In embodiments where the substrate further comprises a silicon nitride, the silicon nitride can be any suitable silicon nitride, many of which are known in the art. When polishing a substrate containing a silicon nitride according to the method of the invention, the chemical mechanical polishing composition of the invention desiccates a low removal rate. For example, when polishing a substrate containing a silicon nitride according to an embodiment of the invention, the polishing composition desiccates approximately Or lower, for example, about or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately Or lower, or about Or even lower silicon nitride removal rates. In some embodiments, the polishing composition exhibits silicon nitride removal rates that are too low to be detected.

[0055] In embodiments where the substrate further comprises a titanium nitride, the titanium nitride can be any suitable titanium nitride, many of which are known in the art. When polishing a substrate containing a titanium nitride according to the method of the invention, the chemical mechanical polishing composition of the invention desiccates a low removal rate. For example, when polishing a substrate containing a titanium nitride according to an embodiment of the invention, the polishing composition desiccates approximately Or lower, for example, about or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately or lower, approximately Or lower, or about Or even lower titanium nitride removal rates. In some embodiments, the polishing composition exhibits titanium nitride removal rates that are too low to be detected.

[0056] When the substrate is polished, the polishing composition of the present invention, as determined by suitable techniques, unsurprisingly exhibits low particle defects. Particle defects on a substrate polished with the polishing composition of the present invention can be measured by any suitable technique. For example, laser light scattering techniques, such as dark field normal beam recombination (DCN) and dark field oblique beam recombination (DCO), can be used to measure particle defects on the polished substrate. Instruments suitable for evaluating particle defects can be purchased from, for example, KLA-Tencor (e.g., a SURFSCAN operating at a 120 nm threshold or a 160 nm threshold). TM SPI instruments).

[0057] The chemical mechanical polishing composition and method of the present invention are particularly suitable for use in conjunction with a chemical mechanical polishing apparatus. Typically, the apparatus includes a platform, a polishing pad, and a carrier. When in use, the platform is in motion and has a speed generated by track, linear, or circular motion. The polishing pad contacts the platform and moves with it during motion. The carrier holds a substrate for polishing by contacting and moving the substrate relative to the surface of the polishing pad. Polishing of the substrate occurs by placing the substrate in contact with the polishing pad and polishing composition of the present invention, and then moving the polishing pad relative to the substrate to polish the substrate by grinding at least a portion of the substrate.

[0058] The substrate can be polished using any suitable polishing pad (e.g., polishing surface) with a chemical mechanical polishing composition. Suitable polishing pads include, for example, fabric and non-woven polishing pads. Furthermore, suitable polishing pads may contain any suitable polymer with different densities, hardness, thickness, compressibility, compression resilience, and compressive modulus. Suitable polymers include, for example, polyvinyl chloride, polyvinyl fluoride, nylon, fluorocarbons, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, their co-formations, and mixtures thereof. Soft polyurethane polishing pads are particularly suitable for use in conjunction with the polishing method of the present invention. Typical pads include (but are not limited to) SURFIN. TM 000, SURFIN TM SSW1, SPM3100 (obtained from companies such as Emily Technologies), POLITEX TM EPIC TMD100 pad (purchased from Cabot Microelectronics), IC1010 pad (purchased from Dow, Inc.), and Fujibo POLYPAS TM 27.

[0059] Desiredly, chemical mechanical polishing (CMP) equipment further includes in-situ polishing endpoint detection systems, many of which are known in the art. Techniques for inspecting and monitoring the polishing process by analyzing light or other radiation reflected from the surface of the substrate being polished are known in the art. These methods are described, for example, in U.S. Patent Nos. 5,196,353, 5,433,651, 5,609,511, 5,643,046, 5,658,183, 5,730,642, 5,838,447, 5,872,633, 5,893,796, 5,949,927, and 5,964,643. Desiredly, the inspection or monitoring of the progress of the polishing process on the substrate being polished enables the determination of the polishing endpoint, i.e., determining when to terminate the polishing process on a particular substrate.

[0060] The aspects of the invention described herein (including embodiments) may be advantageous, either alone or in combination with one or more other aspects or embodiments. Without limiting the foregoing description, certain non-limiting embodiments of this disclosure numbered 1 to 46 are provided below. As those skilled in the art will recognize upon reading this disclosure, each of the individually numbered embodiments may be used or combined with any of the foregoing or subsequent individually numbered embodiments. This is intended to support all such combinations of embodiments, but not limited to the combinations of embodiments explicitly provided below:

[0061] Implementation Plan

[0062] (1) In embodiment (1), a chemical mechanical polishing composition is presented, comprising:

[0063] (a) Silica abrasive;

[0064] (b) Surfactants;

[0065] (c) Iron cations;

[0066] (d) Optional ligands; and

[0067] (e) Water,

[0068] The silica abrasive has a negative zeta potential in the chemical mechanical polishing composition.

[0069] (2) The polishing composition presented in embodiment (2) is as in embodiment 1, wherein the polishing composition comprises about 0.001% by weight to about 10% by weight of silicon oxide abrasive.

[0070] (3) The polishing composition presented in embodiment (3) is as in embodiment 1 or embodiment 2, wherein the polishing composition contains about 0.05% by weight to about 5% by weight of silicon oxide abrasive.

[0071] (4) The polishing composition presented in embodiment (4) is any one of embodiments (1) to (3), wherein the silicon oxide abrasive is colloidal silicon oxide.

[0072] (5) The polishing composition presented in embodiment (5) is any one of embodiments (1) to (4), wherein the polishing composition has a pH of about 1 to about 7.

[0073] (6) The polishing composition presented in embodiment (6) is any one of embodiments (1) to (5), wherein the polishing composition has a pH of about 1 to about 4.

[0074] (7) The polishing composition presented in embodiment (7) is any one of embodiments (1) to (6), wherein the surfactant is a cationic surfactant.

[0075] (8) The polishing composition presented in embodiment (8) is as in embodiment (7), wherein the cationic surfactant comprises a quaternary ammonium salt.

[0076] (9) In embodiment (9), a polishing composition as in embodiment (7) is presented, wherein the cationic surfactant is selected from N,N,N',N',N'-pentamethyl-N-tallow alkyl-1,3-propane diammonium chloride, (oxydi-2,1-ethanediyl)bis(cocoyl)dimethylammonium dichloride, 3-methacryloylaminopropyl-trimethyl-ammonium chloride "(MAPTAC"), 3-acryloylaminopropyl-trimethyl-ammonium chloride "(APTAC"), diallyl dimethylammonium chloride ("DADMAC"), 2-(acryloyloxy)-N,N,N-trimethylethylammonium chloride ("DMAEA.MCQ"), 2-(methacryloyloxy)-N,N,N-trimethylethylammonium chloride "(DMAEM.MCQ"), N,N-dimethylaminoethyl acrylate benzyl chloride "(DMAEA.BCQ"), N,N-dimethylaminoethyl methacrylate benzyl chloride ("DMAEM.BCQ"), and combinations thereof.

[0077] (10) The polishing composition presented in embodiment (1) is any one of embodiments (1) to (6), wherein the surfactant is an anionic surfactant.

[0078] (11) In embodiment (11), a polishing composition as in embodiment (10) is presented, wherein the anionic surfactant is selected from alkyl sulfonic acids, alkyl sulfonates, aryl sulfonic acids, aryl sulfonates, alkyl aryl sulfonic acids, alkyl aryl sulfonates, and combinations thereof.

[0079] (12) In embodiment (12), a polishing composition as in embodiment (10) is presented, wherein the anionic surfactant is selected from saturated or unsaturated C6-C. 40 Alkyl sulfonates, saturated or unsaturated C6-C 40 Alkyl sulfonic acids, saturated or unsaturated C6-C 40 Alkylbenzene sulfonates, saturated or unsaturated C6-C 40 Alkylbenzene sulfonic acids and combinations thereof.

[0080] (13) The polishing composition presented in embodiment (13) is as in any one of embodiments (1) to (12), wherein the iron cation is present in the polishing composition in an amount of about 1 ppm to about 100 ppm.

[0081] (14) The polishing composition presented in embodiment (14) is as in any one of embodiments (1) to (13), wherein the iron cation is present in the polishing composition in an amount of about 10 ppm to about 80 ppm.

[0082] (15) The polishing composition presented in embodiment (15) is any one of embodiments (1) to (14), wherein the polishing composition comprises a ligand.

[0083] (16) The polishing composition presented in embodiment (16) is as in embodiment (15), wherein the ligand comprises an olefin moiety, an alkyne moiety, a diacid moiety, an alcohol moiety, or a combination thereof.

[0084] (17) The polishing composition presented in embodiment (17) is as in embodiment (15) or embodiment (16), wherein the ligand comprises an olefin portion and a diacid portion.

[0085] (18) The polishing composition presented in embodiment (18) is as in embodiment (15) or embodiment (16), wherein the ligand comprises an alkyne moiety.

[0086] (19) The polishing composition presented in embodiment (19) is as in embodiment (18), wherein the ligand further comprises an alcohol moiety.

[0087] (20) In embodiment (20), a polishing composition as in embodiment (15) or embodiment (16) is presented, wherein the ligand is selected from succinic acid, maleic acid, malonic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, tartaric acid, 3,5-dimethyl-1-hexyn-3-ol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol ethoxylate, 2,5-dimethyl-3-hexyn-2,5-diol, 3-methyl-1-pentyn-3-ol, and combinations thereof.

[0088] (21) The polishing composition presented in embodiment (21) is as in any one of embodiments (1) to (20), wherein the silicon oxide abrasive has a ζ potential of -10mV or less in the chemical mechanical polishing composition.

[0089] (22) The polishing composition presented in embodiment (22) is as in any one of embodiments (1) to (21), wherein the silicon oxide abrasive has a ζ potential of -20 mV or less in the chemical mechanical polishing composition.

[0090] (23) The polishing composition presented in embodiment (23) is as in any one of embodiments (1) to (22), wherein the silicon oxide abrasive has a ζ potential of -30 mV or less in the chemical mechanical polishing composition.

[0091] (24) In embodiment (24), a method for chemically and mechanically polishing a substrate is presented, comprising:

[0092] (i) Provide a substrate.

[0093] (ii) Provide polishing pads

[0094] (iii) Providing a chemical mechanical polishing composition comprising:

[0095] (a) Silica abrasive;

[0096] (b) Surfactants;

[0097] (c) Iron cations;

[0098] (d) Optional ligands; and

[0099] (e) Water,

[0100] The silica abrasive has a negative zeta potential in the chemical mechanical polishing composition.

[0101] (iv) Bring the substrate into contact with the polishing pad and the chemical mechanical polishing composition, and

[0102] (v) Polishing the substrate by moving the polishing pad and the chemical mechanical polishing composition relative to the substrate to grind at least a portion of the substrate.

[0103] (25) The method of embodiment (24) is presented in embodiment (25), wherein the polishing composition comprises about 0.001% by weight to about 10% by weight of silicon oxide abrasive.

[0104] (26) The method of embodiment (24) or embodiment (25) is presented in embodiment (26), wherein the polishing composition comprises about 0.05% by weight to about 5% by weight of silicon oxide abrasive.

[0105] (27) The method presented in embodiment (27) is as in any one of embodiments (24) to (26), wherein the silicon oxide abrasive is colloidal silicon oxide.

[0106] (28) The method of any one of embodiments (24) to (27) is presented in embodiment (28), wherein the polishing composition has a pH of about 1 to about 7.

[0107] (29) The method of any one of embodiments (24) to (28) is presented in embodiment (29), wherein the polishing composition has a pH of about 1 to about 4.

[0108] (30) The method presented in embodiment (30) is as described in any one of embodiments (24) to (29), wherein the surfactant is a cationic surfactant.

[0109] (31) The method of embodiment (30) is presented in embodiment (31), wherein the cationic surfactant comprises a quaternary ammonium salt.

[0110] (32) In embodiment (32), the method of embodiment (30) is presented, wherein the cationic surfactant is selected from N,N,N',N',N'-pentamethyl-N-tallow alkyl-1,3-propane diammonium chloride, (oxydi-2,1-ethanediyl)bis(cocoyl)dimethylammonium dichloride, 3-methacryloylaminopropyl-trimethyl-ammonium chloride (“MAPTAC”), 3-acryloylaminopropyl-trimethyl-ammonium chloride (“APTAC”), diallyl dimethylammonium chloride (“DADMAC”), 2-(acryloyloxy)-N,N,N-trimethylethylammonium chloride (“DMAEA.MCQ”), 2-(methacryloyloxy)-N,N,N-trimethylethylammonium chloride (“DMAEM.MCQ”), N,N-dimethylaminoethyl acrylate benzyl chloride (“DMAEA.BCQ”), N,N-dimethylaminoethyl methacrylate benzyl chloride (“DMAEM.BCQ”), and combinations thereof.

[0111] (33) The method presented in embodiment (33) is as described in any one of embodiments (24) to (29), wherein the surfactant is an anionic surfactant.

[0112] (34) The method of embodiment (33) is presented in embodiment (34), wherein the anionic surfactant is selected from alkyl sulfonic acids, alkyl sulfonates, aryl sulfonic acids, aryl sulfonates, alkyl aryl sulfonic acids, alkyl aryl sulfonates, and combinations thereof.

[0113] (35) The method of embodiment (33) is presented in embodiment (35), wherein the anionic surfactant is selected from saturated or unsaturated C6-C surfactants. 40 Alkyl sulfonates, saturated or unsaturated C6-C 40 Alkyl sulfonic acids, saturated or unsaturated C6-C 40 Alkylbenzene sulfonates, saturated or unsaturated C6-C 40 Alkylbenzene sulfonic acids and combinations thereof.

[0114] (36) The method of any one of embodiments (24) to (35) is presented in embodiment (36), wherein the iron cation is present in the polishing composition in an amount of about 1 ppm to about 100 ppm.

[0115] (37) The method of any one of embodiments (24) to (36) is presented in embodiment (37), wherein the iron cation is present in the polishing composition in an amount of about 10 ppm to about 80 ppm.

[0116] (38) The method of any one of embodiments (24) to (37) is presented in embodiment (38), wherein the polishing composition comprises a ligand.

[0117] (39) The method of embodiment (38) is presented in embodiment (39), wherein the ligand comprises an olefin moiety, an alkyne moiety, a diacid moiety, an alcohol moiety, or a combination thereof.

[0118] (40) The method presented in embodiment (40) is as in embodiment (38) or embodiment (39), wherein the ligand comprises an olefin portion and a diacid portion.

[0119] (41) The method presented in embodiment (41) is as in embodiment (38) or embodiment (39), wherein the ligand comprises an alkyne portion.

[0120] (42) The method of embodiment (41) is presented in embodiment (42), wherein the ligand further comprises an alcohol moiety.

[0121] (43) The method presented in embodiment (43) is as described in any one of embodiment (38) or embodiment (39), wherein the ligand is selected from succinic acid, maleic acid, malonic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, tartaric acid, 3,5-dimethyl-1-hexyn-3-ol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol ethoxylate, 2,5-dimethyl-3-hexyn-2,5-diol, 3-methyl-1-pentyn-3-ol, and combinations thereof.

[0122] (44) The method of any one of embodiments (24) to (43) is presented in embodiment (44), wherein the silicon oxide abrasive has a ζ potential of -10mV or less in the chemical mechanical polishing composition.

[0123] (45) The method of any one of embodiments (24) to (44) is presented in embodiment (45), wherein the silicon oxide abrasive has a ζ potential of -20 mV or less in the chemical mechanical polishing composition.

[0124] (46) The method of any one of embodiments (24) to (45) is presented in embodiment (46), wherein the silicon oxide abrasive has a ζ potential of -30 mV or less in the chemical mechanical polishing composition.

[0125] (47) In embodiment (47), a method as described in any one of embodiments (24) to (46) is presented, wherein the substrate comprises a carbon-based film, and wherein at least a portion of the carbon-based film is removed at a rate of Grinding is used to polish the substrate.

[0126] (48) In embodiment (48), the method of embodiment (47) is presented, wherein the substrate further comprises silicon oxide, silicon nitride, polysilicon, titanium nitride, or a combination thereof, and wherein at least a portion of the silicon oxide, silicon nitride, polysilicon, or titanium nitride is removed at a rate of Grinding is used to polish the substrate.

[0127] (49) In embodiment (49), the method as in embodiment (48) is presented, wherein the removal rate of the carbon-based membrane is... Greater than the removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride

[0128] (50) In embodiment (50), the method as in embodiment (49) is presented, wherein the removal rate of the carbon-based membrane is... It is the removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride. At least 10 times.

[0129] (51) In embodiment (51), the method as in embodiment (50) is presented, wherein the removal rate of the carbon-based membrane is... It is the removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride. At least 20 times.

[0130] (52) In embodiment (52), the method as in embodiment (51) is presented, wherein the removal rate of the carbon-based membrane is... It is the removal rate of the silicon oxide, silicon nitride, polycrystalline silicon, or titanium nitride. At least 40 times.

[0131] Example

[0132] These examples further illustrate the invention, but should not, of course, be considered as limiting its scope in any way.

[0133] The following abbreviations are used throughout the embodiments: removal rate (RR); carbon film (CF); spin-coated carbon-containing dielectric (SOD); tetraethyl orthosilicate (TEOS); polysilicon (polySi); silicon nitride (SiN); and molecular weight (MW).

[0134] In the following examples, SOD, TEOS, polySi, or SiN were coated onto silicon, and the resulting patterned substrate was polished using a Logitech 2 benchtop polisher at a pressure of 2 PSI (13.7 kPa) with a Fujibo pad conditioned to the commercially labeled A82 product (3M, St. Paul, MN). The Logitech polishing parameters were as follows: head speed = 93 rpm, platform speed = 87 rpm, total flow rate = 150 mL / min. The removal rate was calculated by measuring the film thickness using a spectroscopic ellipsometry and subtracting the final thickness from the initial thickness.

[0135] Example 1

[0136] This embodiment demonstrates the preparation of a polishing composition according to the present invention comprising a silica abrasive, a surfactant, iron cations, and optionally ligands. Polishing compositions 1A to 1F of the present invention and comparative polishing compositions 1G and 1H were used in Examples 2 to 6 below to demonstrate the effectiveness of the claimed polishing method.

[0137] For each of the compositions of the present invention used in Examples 2 to 6, silica particles having a positive Bunsen zeta potential (particle A: treated spherical silica particles having cationic properties over a wide pH range and a dynamic light scattering particle size of 150 nm) or a negative Bunsen zeta potential (particle B: treated elliptical silica particles having anionic properties over a wide pH range and a dynamic light scattering particle size of 75 to 80 nm) are combined with an anionic surfactant or a cationic surfactant. For the purposes of the compositions of the present invention used in Examples 2 to 6, the anionic surfactant is CALSOFT. TM LPS-99 (dodecylbenzenesulfonic acid; commercially available from Pilot Chemical Corporation, West Chester, OH) or ZETASPERSE TM Z2300 (Ethoxylated C6-C) 12 Alcohol (CAS 68439-45-2) and C 10 -C 14 A mixture of alkyl aryl sulfonates (commercially available from Air Products, Allentown, PA), and the cationic surfactant is diallyl dimethyl ammonium chloride (“DADMAC”). Iron cations (i.e., iron compounds as described herein), ligands, and / or potassium nitrate (KNO3) are added to each of the polishing compositions of the invention in the amounts specified in Table 1, and the pH of each polishing composition of the invention is adjusted to 2.5. Each of the polishing compositions A through F of the invention has a zeta potential of less than 0 mV for the resulting silica particles, i.e., a negative zeta potential.

[0138] The comparative polishing composition 1G differs from the polishing compositions A to F of the present invention because it does not contain surfactants or iron cations and has a resulting silicon oxide particle zeta potential greater than 0 mV, i.e., a positive zeta potential. The silicon oxide particles used in the comparative polishing composition 1G are particles C, which are elliptical silicon oxide particles that are cationic over a wide pH range, have a dynamic light-scattering particle size of 45 to 55 nm, and possess a positive Bunsen zeta potential.

[0139] Except that the comparative polishing composition 1H does not contain iron cations, the comparative polishing composition 1H is similar to the polishing composition 1A of the present invention.

[0140] The resulting compositions are summarized in Table 1.

[0141] Table 1: Polishing Compositions

[0142]

[0143] Example 2

[0144] This embodiment demonstrates the advantageous polishing properties provided by the polishing composition prepared according to the present invention.

[0145] Patterned substrates containing SOD, TEOS, SiN, or polySi were polished under the same conditions as those defined in Table 1 of Example 1, using polishing compositions 1A to 1G. In this specific example, an SOD patterned substrate was used as a substitute for measuring the carbon removal rate of commercially available carbon film materials. After polishing, the RR of SOD, TEOS, SiN, and polySi was measured, and the results are presented in Table 2.

[0146] Table 2: Polishing Removal Rate

[0147]

[0148] As is clear from Table 2, the polishing compositions 1A and 1C to 1F of the present invention provide SOD removal rates consistent with those of the comparative polishing composition 1G. However, as evidenced by the high TEOS and polySi removal rates of the comparative polishing composition 1G, each of the polishing compositions 1A to 1F of the present invention exhibits significantly higher selectivity for polishing SOD compared to the comparative polishing composition 1G. Therefore, Table 2 shows that, relative to polishing compositions that do not contain silica abrasives with negative zeta potentials and iron cations, polishing compositions containing silica abrasives with negative zeta potentials and iron cations provide higher SOD RR and improve selectivity for the removal of carbon-based films relative to silicon-based films.

[0149] Example 3

[0150] This example demonstrates the effect of ligand and iron cation concentrations on the polishing performance provided by the polishing composition prepared according to the present invention.

[0151] As defined in Table 1 of Example 1, the patterned substrate containing SOD was polished under the same conditions as polishing compositions 1B to 1E. In this specific embodiment, the SOD patterned substrate was used as a substitute for measuring the carbon film removal rate of commercially available carbon film materials. After polishing, the RR of SOD was measured, and the results are presented in Table 3.

[0152] Table 3: Ligand-based carbon removal rates Impact

[0153]

[0154] As is clear from Table 3, polishing compositions 1C to 1E, which contain ligands of olefins or alkynes in combination with diacids or alcohols, produce higher SOD removal rates than polishing composition 1B, despite having a lower iron cation concentration.

[0155] Therefore, Table 3 shows that, as confirmed by the SOD removal rate, polishing compositions containing ligands having an olefinic moiety, an alkyne moiety, a diacid moiety, an alcohol moiety, or a combination thereof (and preferably an olefinic or alkyne moiety combined with a diacid or alcohol) require less iron cations and can produce higher carbon removal rates.

[0156] Example 4

[0157] This example demonstrates the effect of ligand and iron cation concentrations on the polishing performance provided by the polishing composition prepared according to the present invention.

[0158] Patterned substrates containing carbon films, such as those described in Weigan et al. (“Evaluating spin-on carbon materials at low temperatures for high wiggling resistance.” Advanced Etch Technology for Nanopatterning II., Vol. 8685, International Society for Optics and Photonics, 2013) and Kim et al. (“Study on the etching characteristics of amorphous carbon layer in oxygen plasma with carbonyl sulfide.” Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, (2013), 31.2:021301, pp. 1-7), were polished as defined in Table 1 of Example 1. After polishing, the CF RR was measured, and the predicted results are presented in Table 4 as estimated percentages of the SOD removal rate values ​​provided in Table 3.

[0159] Table 4: Ligand-based carbon removal rates Impact

[0160]

[0161] As the predictions presented in Table 4 clearly demonstrate, it is believed that, despite having a lower iron cation concentration than polishing composition 1B, polishing compositions 1C to 1E containing ligands of olefins or alkynes in combination with diacids or alcohols will produce higher carbon removal rates than polishing composition 1B which contains ligands of only diacids (see Table 3 of Example 3).

[0162] As will also be clear from Table 4, it is believed that the CF RR produced by polishing compositions 1B to 1E, as described in Examples 2 and 3, will be lower than the removal rate of SOD, which is used as a substitute for measuring the carbon film removal rate of commercially available carbon film materials. Furthermore, it is believed that polishing composition 1E will have the highest CF RR of polishing compositions 1B to 1E.

[0163] Example 5

[0164] This example demonstrates the effect of iron cation concentration on the polishing performance provided by the polishing composition prepared according to the present invention.

[0165] As defined in Table 1 of Example 1, a patterned substrate containing SOD was polished under the same conditions as polishing composition 1A of the present invention or comparative polishing composition 1H. In this specific embodiment, an SOD patterned substrate was used as a substitute for measuring the carbon film removal rate of commercially available carbon film materials. After polishing, the RR of SOD was measured, and the results are presented in Table 5.

[0166] Table 5: Effect of iron cation concentration on carbon removal rate Impact

[0167]

[0168] As is clear from Table 5, the polishing composition 1A of the present invention, containing iron cations, produces an SOD removal rate consistent with that produced by the comparative polishing composition 1H. Without wishing to be bound by any particular theory, it is believed that polishing compositions containing silicon oxide abrasives with a negative zeta potential are so effective in removing SOD that SOD patterned substrates may not be a suitable alternative for measuring the effect of iron cation concentration on polishing performance. In other words, while suitable for determining the selectivity of the compositions of the present invention for carbon films relative to TEOS, SiN, and polySi, SOD substrates may not be suitable for determining the maximum carbon film removal rate of the polishing compositions of the present invention.

[0169] As further described in Example 6, it is believed that when there are no iron cations in the polishing composition, the carbon film removal rate of commercially available carbon film materials can be significantly reduced.

[0170] Example 6

[0171] This example demonstrates the effect of iron cation concentration on the polishing performance provided by the polishing composition prepared according to the present invention.

[0172] Patterned substrates containing carbon films, such as those described in Weigan et al. (“Evaluating spin-on carbon materials at low temperatures for high wiggling resistance.” Advanced Etch Technology for Nanopatterning II., Vol. 8685, International Society for Optics and Photonics, 2013) and Kim et al. (“Study on the etching characteristics of amorphous carbon layer in oxygen plasma with carbonyl sulfide.” Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, (2013), 31.2:021301, pp. 1-7), were polished as defined in Table 1 of Example 1. After polishing, the CF RR was measured, and the predicted results are presented as an estimated percentage of the SOD removal rate values ​​provided in Example 5 in Table 6.

[0173] Table 6: Effect of iron cation concentration on carbon removal rate Impact

[0174]

[0175] As clearly demonstrated by the predictions in Table 6, iron cations are believed to play a crucial role in maintaining a high CF RR. More specifically, it is believed that CF RR can decrease by up to 15% when iron cations are removed from the self-polishing composition 1A.

[0176] It is believed that increasing the iron cation concentration results in a higher carbon film removal rate. However, it is also believed that a higher iron cation concentration can be associated with various defect problems when polishing commercially available carbon film materials. Therefore, it is important to use a desired iron cation concentration to maintain a high carbon film removal rate, high selectivity, and minimal defects. The present invention described herein provides means for maintaining a high carbon film removal rate while avoiding defect problems.

[0177] In this regard, Examples 3 to 6 show that iron cations are essential components for achieving optimal carbon film removal rates, and the level of iron cations necessary to maintain these optimal carbon film removal rates can be reduced by adding ligands having olefinic, alkyne, diacid, alcoholic, or combinations thereof, thereby avoiding defects during carbon film polishing.

[0178] All references cited in this article (including publications, patent applications and patents) are incorporated herein by reference as if each reference were individually and specifically cited for reference and as fully described herein.

[0179] The terms “a,” “an,” “the,” and “at least one,” and similar designations used in describing the scope of the invention (particularly the scope of the appended claims) should be understood to include both singular and plural forms, unless otherwise stated herein or the context clearly contradicts. The term “at least one” (e.g., “at least one of A and B”) following a list of one or more items is interpreted as meaning one of the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise stated herein or the context clearly contradicts. The terms “comprising,” “having,” “including,” and “containing” should be understood as open-ended terms (i.e., meaning “including, but not limited to”), unless otherwise stated. The enumeration of numerical ranges herein is merely a shorthand method of individually referring to each independent value falling within that range, unless otherwise stated herein, and each independent value is introduced in the specification as if it were individually enumerated herein. All methods described herein can be performed in any suitable order, unless otherwise stated herein or clearly contradicted by the context. The use of any and all instances or exemplary language (e.g., "for example") provided herein is for the purpose of better illustrating the invention and not for limiting the scope of the invention, unless otherwise stated. No language in the specification should be construed as indicating that any non-claimed element is necessary for the practice of the invention.

[0180] Preferred embodiments of the invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors encourage those skilled in the art to adopt such variations appropriately, and the inventors encourage the invention to be practiced in ways different from those specifically described herein. Therefore, the invention includes all modifications and equivalents of the subject matter listed in the appended claims as permitted by applicable law. Furthermore, the invention covers any combination of the foregoing elements in all possible variations, unless otherwise stated herein or clearly contradicted by the context.

Claims

1. A chemical mechanical polishing composition for a substrate comprising a carbon-based film, the chemical mechanical polishing composition comprising: (a) 0.001 wt.% to 10 wt.% of a colloidal silica abrasive; (b) a surfactant, wherein the surfactant is a cationic surfactant or an anionic surfactant, wherein the cationic surfactant comprises a quaternary ammonium salt, and the anionic surfactant is selected from the group consisting of an alkyl sulfonic acid, an alkyl sulfonic acid salt, an aryl sulfonic acid, an aryl sulfonic acid salt, an alkyl aryl sulfonic acid, an alkyl aryl sulfonic acid salt, and combinations thereof; (c) 1 ppm to 100 ppm of an iron cation; (d) optionally a ligand; and (e) water, wherein the polishing composition has a pH of 1 to 7, and wherein the silica abrasive has a zeta potential of -10 mV or less in the chemical mechanical polishing composition.

2. The polishing composition of claim 1, wherein the polishing composition comprises 0.05 wt.% to 5 wt.% of the silica abrasive.

3. The polishing composition of claim 1, wherein the polishing composition has a pH of 1 to 4.

4. The polishing composition of claim 1, wherein the cationic surfactant is selected from the group consisting of N,N,N',N',N'-pentamethyl-N-tallowalkyl-1,3-propanediaminium dichloride, (oxybis-2,1-ethanediyl)bis(coconutalkyl)dimethylammonium dichloride, 3-methacrylamidopropyl-trimethyl-ammonium chloride ("MAPTAC"), 3-acrylamidopropyl-trimethyl-ammonium chloride ("APTAC"), diallyldimethylammonium chloride ("DADMAC"), 2-(acryloyloxy)-N,N,N-trimethylethylammonium chloride ("DMAEA.MCQ"), 2-(methacryloyloxy)-N,N,N-trimethylethylammonium chloride ("DMAEM.MCQ"), N,N-dimethylaminoethyl acrylate benzyl chloride ("DMAEA.BCQ"), N,N-dimethylaminoethyl methacrylate benzyl chloride ("DMAEM.BCQ"), and combinations thereof.

5. The polishing composition of claim 1 wherein the anionic surfactant is selected from the group consisting of saturated or unsaturated C6-C 40 alkyl sulfonates, saturated or unsaturated C6-C 40 alkyl sulfonic acids, and combinations thereof. 40 alkyl benzene sulfonates, saturated or unsaturated C6-C 40 alkyl benzene sulfonic acids, and combinations thereof.

6. The polishing composition of claim 1, wherein the iron cation is present in the polishing composition in an amount of 10 ppm to 80 ppm.

7. The polishing composition of claim 1, wherein the polishing composition comprises a ligand and wherein the ligand comprises an olefin moiety, an alkyne moiety, a diacid moiety, an alcohol moiety, or combinations thereof.

8. The polishing composition of claim 7, wherein the ligand is selected from the group consisting of succinic acid, maleic acid, malonic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, tartaric acid, 3,5-dimethyl-1-hexyn-3-ol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate, 2,5-dimethyl-3-hexyn-2,5-diol, 3-methyl-1-pentyn-3-ol, and combinations thereof.

9. A method of chemically mechanically polishing a substrate, comprising: (i) providing a substrate, wherein the substrate comprises a carbon-based film, (ii) providing a polishing pad, (iii) providing a chemical mechanical polishing composition, the chemical mechanical polishing composition comprising: (a) 0.001 wt% to 10 wt% of a colloidal silica abrasive; (b) a surfactant, wherein the surfactant is a cationic surfactant or an anionic surfactant, wherein the cationic surfactant comprises a quaternary ammonium salt, and the anionic surfactant is selected from the group consisting of an alkyl sulfonic acid, an alkyl sulfonic acid salt, an aryl sulfonic acid, an aryl sulfonic acid salt, an alkyl aryl sulfonic acid, an alkyl aryl sulfonic acid salt, and combinations thereof; (c) 1 ppm to 100 ppm of iron cations; (d) optionally a ligand; and (e) water, wherein the polishing composition has a pH of 1 to 7, and wherein the silica abrasive has a zeta potential of -10 mV or less in the chemical mechanical polishing composition, (iv) contacting the substrate with the polishing pad and the chemical mechanical polishing composition, and (v) moving the polishing pad and the chemical mechanical polishing composition relative to the substrate to polish the substrate by abrading at least a portion of the substrate.

10. The method of claim 9, wherein the polishing composition comprises 0.05 wt% to 5 wt% of the silica abrasive.

11. The method of claim 9, wherein the polishing composition has a pH of 1 to 4.

12. The method of claim 9, wherein the cationic surfactant is selected from the group consisting of N,N,N',N',N'-pentamethyl-N-tallowalkyl-1,3-propanediaminium dichloride, (oxybis-2,1-ethanediyl)bis(cocoalkyl)dimethylammonium dichloride, 3-methacrylamidopropyl-trimethyl-ammonium chloride ("MAPTAC"), 3-acrylamidopropyl-trimethyl-ammonium chloride ("APTAC"), diallyldimethylammonium chloride ("DADMAC"), 2-(acryloyloxy)-N,N,N-trimethylethylammonium chloride ("DMAEA.MCQ"), 2-(methacryloyloxy)-N,N,N-trimethylethylammonium chloride ("DMAEM.MCQ"), N,N-dimethylaminoethyl acrylate benzyl chloride ("DMAEA.BCQ"), N,N-dimethylaminoethyl methacrylate benzyl chloride ("DMAEM.BCQ"), and combinations thereof.

13. The method of claim 9, wherein the anionic surfactant is selected from the group consisting of saturated or unsaturated C6-C 40 alkyl sulfonates, saturated or unsaturated C6-C 40 alkyl sulfonic acids, and combinations thereof. 40 alkyl benzene sulfonates, saturated or unsaturated C6-C 40 alkyl benzene sulfonic acids, and combinations thereof.

14. The method of claim 9, wherein the polishing composition comprises a ligand and wherein the ligand comprises an olefin moiety, an alkyne moiety, a diacid moiety, an alcohol moiety, or combinations thereof.

15. The method of claim 14, wherein the ligand is selected from the group consisting of succinic acid, maleic acid, malonic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, tartaric acid, 3,5-dimethyl-1-hexyn-3-ol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate, 2,5-dimethyl-3-hexyn-2,5-diol, 3-methyl-1-pentyn-3-ol, and combinations thereof.

Images