Amphiphilic abrasive particles and their use for chemical mechanical planarization

Abstract

A colloidally stable amphiphilic abrasive particle dispersion containing amphiphilic abrasive particles is provided. The surface of each colloidally stable amphiphilic abrasive particle comprises a hydrophilic portion and a hydrophobic portion. A chemical mechanical planarization (CMP) polishing composition, a chemical mechanical planarization (CMP) method, and a chemical mechanical planarization (CMP) system using the colloidally stable amphiphilic abrasive particle dispersion are also provided. The CMP composition provides a high removal rate of tungsten (W), a suppressed removal rate of silicon oxide (TEOS), and therefore excellent W:TEOS selectivity for chemical mechanical planarization of tungsten surfaces.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 387,523, filed December 15, 2022, which is incorporated herein by reference as if fully set forth. [Background technology]

[0002] The present invention relates to colloidally stable amphiphilic abrasive particles, chemical mechanical planarization (CMP) compositions, chemical mechanical planarization (CMP) methods, and chemical mechanical planarization (CMP) systems.

[0003] More specifically, a chemical mechanical planarization (CMP) polishing composition, a chemical mechanical planarization (CMP) method, and a chemical mechanical planarization (CMP) system are provided that use a colloidally stable amphiphilic abrasive particle dispersion containing amphiphilic abrasive particles. The amphiphilic abrasive particles have a highly non-polar (or non-polar) and inert surface toward silicon oxide (TEOS) films (deposited using tetraethyl orthosilicate as a precursor), while being water-dispersible and colloidally stable. Furthermore, the amphiphilic abrasive particles have a low silanol density because the silanol groups are converted with inert silanes and have a positive charge in the low acidic pH range. The amphiphilic abrasive particles are useful for inhibiting CMP polishing of silicon oxide, silicon nitride, or polysilicon.

[0004] In the semiconductor industry, chemical mechanical planarization (CMP) is a well-known technique applied to the fabrication of advanced photonic, microelectromechanical, and microelectronic materials and devices, such as semiconductor wafers. Semiconductor devices have structured layers and multilayer interconnects, including stacked thin films of one or more of the following materials: titanium (Ti), titanium nitride (TiN), tantalum (Ta), aluminum-copper (Al-Cu), aluminum-silicon (AlSi), copper (Cu), tungsten (W), doped polysilicon (polySi), and various combinations thereof. Furthermore, transistors or groups of transistors are often isolated from one another by using trenches filled with insulating materials such as silicon dioxide, silicon nitride, and / or polysilicon. The deposition of semiconductor devices is performed in a variety of ways, and after each step, a CMP process is performed to ensure that the deposited layers are flat and have lower nm-scale surface roughness.

[0005] CMP utilizes the interplay of chemical and mechanical action to achieve planarity of the surface to be polished. The chemical action is provided by a chemical composition, also called a CMP slurry, CMP formulation, or CMP composition. The mechanical action is usually performed by a polishing pad, which is typically pressed against the surface to be polished and attached to a moving platen. The platen motion is usually linear, rotational, or orbital.

[0006] In a typical CMP process step, a rotating wafer holder brings the wafer to be polished into contact with a polishing pad, and a CMP composition is usually applied between the wafer to be polished and the polishing pad.

[0007] Chemical mechanical planarization (CMP) is a process used in the fabrication of electronic components such as memory chips or microprocessor chips. Structured layers are deposited by various methods, and after each step, a CMP process is performed to ensure that the deposited layers are flat and have lower nanometer-scale surface roughness.

[0008] Typically, different materials are deposited on top of each other in very complex structures, and the CMP process must be stopped precisely when the material to be planarized is to be removed and the underlying material exposed. This is achieved, on the one hand, by perfectly controlling the planarization time, but also by formulating CMP slurries to exhibit maximum selectivity in aggressiveness between the materials to be planarized and those to be preserved.

[0009] Therefore, what defines the effectiveness of a CMP slurry is the combination of an effectively high removal rate of the material to be planarized and a very low removal rate of the material to be preserved.

[0010] In addition to various additives and varying pH that can be used to adjust slurry selectivity, the CMP abrasive material is a major contributor to the removal rate and selectivity of the slurry, as disclosed in U.S. Pat. No. 9,028,572.

[0011] This is especially true for W-CMP applications, for example, where the slurry should exhibit a high removal rate for oxidized W metal and a very low removal rate for silicon oxide, which should remain largely undamaged.

[0012] Even after known surface modification treatments, typical CMP abrasives have many polar groups on their surfaces that can form electrostatic or hydrogen bonds with silica and other polar surfaces, resulting in undesirably high silicon oxide removal rates. Therefore, W-CMP slurry formulators have struggled to achieve high selectivity with existing abrasive materials.

[0013] Currently available CMP abrasives do not inherently exhibit high selectivity and must be mixed with many additives to achieve the desired selectivity, which, in turn, can present problems with slurry stability or reduced removal rate of the material to be planarized.

[0014] The present invention provides amphiphilic abrasive particles having a surface that is highly non-polar and inert toward silicon oxide, and also provides CMP polishing compositions, CMP methods, and CMP systems that utilize the amphiphilic abrasive particles. These and other advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein. Summary of the Invention

[0015] The present invention provides colloidally stable amphiphilic abrasive dispersions containing amphiphilic abrasive particles. CMP compositions, CMP methods, and CMP systems that use the colloidally stable amphiphilic abrasive dispersions are also provided.

[0016] In one aspect, colloidally stable amphiphilic abrasive particles are provided. The amphiphilic abrasive particles have both hydrophilic and hydrophobic moieties on their surfaces, and therefore have a highly non-polar and inert surface relative to silicon oxide. The amphiphilic abrasive particles in the dispersion are colloidally stable.

[0017] Each of the hydrophilic moieties is independently at least one selected from the group consisting of amines and substituted amines; amino groups, ammonium; N-containing groups selected from the group including ammonium and substituted ammonium groups, including, but not limited to, alkylammonium groups, including alkyls with less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably, including, but not limited to, N-containing groups.

[0018] Each of the hydrophilic moieties independently comprises at least one selected from the group consisting of, but not limited to, an amine, an amino group, an ammonium, an alkylammonium group including alkyls with less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms.

[0019] As an example, the hydrophilic moiety can be an amino group and the hydrophobic moiety can be a trimethylsilane group.

[0020] The colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic to hydrophobic moieties in the range of 1.00:0.01 to 1.00:10.00, 1.00:0.25 to 1.00:5.00, 1.00:0.30 to 1.00:3.00, 1.00:0.40 to 1.00:2.50, or 1.00:0.50 to 1.00:2.00.

[0021] The colloidally stable amphiphilic abrasive particles have any size distribution, including but not limited to, unimodal, bimodal, or multimodal, any shape, including but not limited to, spherical, elongated, or branched, dispersed in a solvent, including water, and a mean particle size (MPS) ranging from 1 to 500 nm, 2 to 300 nm, 5 to 200 nm, 10 to 150 nm, or 20 to 100 nm. MPS can be measured by dynamic light scattering (DLS).

[0022] In another aspect, a. providing base abrasive particles having reactive M-OH groups on their surfaces, the base abrasive particles being dispersed in a solvent; b. modifying the surface of the base abrasive particles with a first-step surface modifier having at least one hydrophilic group and at least one first reactive group capable of forming a covalent bond with a reactive M-OH group to obtain a one-step modified abrasive particle; c. modifying the surface of the one-step modified abrasive particle with a second-step surface modifier having at least one hydrophobic group and at least one second reactive group capable of forming a covalent bond with the reactive X-OH group on the surface of the one-step modified abrasive particle to obtain an amphiphilic abrasive particle; During the ceremony, M in the reactive M-OH group is selected from the group including, but not limited to, metals or metalloids, including Si, Ce, Al, Zr, and hybrids and / or mixtures of metals and metalloids; X in the reactive X-OH group is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and / or mixtures thereof; A method for making colloidally stable amphiphilic abrasive particles is provided, wherein the solvent is selected from the group consisting of water, alcohols, ketones, esters, ethers, glycols, and combinations thereof.

[0023] The at least one first reactive group and the at least one second reactive group are independently selected from the group consisting of si-alkoxides, si-halides (preferably chlorides), oximates, acetates, si-hydroxides, and combinations thereof, preferably silicon methoxide and silicon ethoxide.

[0024] Preferably, the first step surface modifier includes, but is not limited to, a silane containing at least one hydrophilic group, and the second step surface modifier includes, but is not limited to, a silane containing at least one hydrophobic group.

[0025] The at least one hydrophilic group comprises an N-containing group selected from the group comprising amine; substituted amine; amino group; ammonium; alkylammonium group including alkyl having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms, including, but not limited to, ammonium group and substituted ammonium group; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether group; combinations thereof; preferably, an N-containing group selected from the group comprising amine, amino group, ammonium, or alkylammonium group, including, but not limited to,

[0026] The first step surface modifiers can also react among themselves to form a covalently bonded polymer shell (crosslinked shell) around the base abrasive particles.

[0027] Second step surface modifiers include, but are not limited to, silanes having at least one hydrophobic group, including, but not limited to, a methyl, ethyl, propyl, butyl, phenyl, benzyl, tolyl, or xylyl group.

[0028] Second-step surface modifiers include, but are not limited to, silanes having at least two, preferably at least three hydrophobic groups, including alkyls having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms; or aryls having less than 20 C atoms, or less than 10 C atoms; and combinations thereof.

[0029] The total amount of the first step surface modifier and the second step surface modifier includes, but is not limited to, 0.01 to 1.0 mmol / g (mass of abrasive calculated as dry substance), 0.025 to 0.8 mmol / g, 0.05 to 0.5 mmol / g, or 0.1 to 0.4 mmol / g.

[0030] First-step surface modifiers include, but are not limited to, amino-polyether silanes, betaine-type silanes, 3-aminopropyl derivatives of ethoxysilanes or methoxysilanes, such as 3-aminopropylmethyldimethoxysilane, and combinations thereof, preferably 3-aminopropylmethyldimethoxysilane.

[0031] The first step surface modifier can be used in any mixture with other functional or non-functional reactants such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and combinations thereof.

[0032] Examples of second-step surface modifiers include, but are not limited to, trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium trimethylsilanoate, triethylmethoxysilane, and combinations thereof.

[0033] Preferred second step surface modifiers are trimethylmethoxysilane, trimethylethoxysilane, and combinations thereof.

[0034] In yet another aspect, there is provided a CMP polishing composition comprising the above-described colloidally stable amphiphilic abrasive particles dispersed in water, the aqueous solvent including, but not limited to, alcohols, ethers, ketones, and mixtures thereof.

[0035] The CMP polishing composition optionally comprises: Organic and inorganic salts as colloid stabilizers; catalysts, including but not limited to fluoride ions, metal salts, or metal alkoxides such as titanium isopropoxide; Acid / base pH buffers; Biocides; oxidizing agents; catalyst; chelating agents; dishing and erosion inhibitors; and and at least one of a corrosion inhibitor.

[0036] In another aspect, there is provided a method of chemical mechanical polishing (CMP) a substrate having at least one surface comprising tungsten using the above-described chemical mechanical polishing (CMP) composition.

[0037] Specifically, CMP compositions using colloidally stable amphiphilic abrasive particle dispersions provide high removal rates of tungsten (W), suppressed removal rates of TEOS, and therefore excellent W:TEOS selectivity for chemical mechanical planarization of tungsten surfaces (i.e., W CMP), especially at acidic low pH. DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention relates to colloidally stable amphiphilic abrasive particles, and provides chemical-mechanical polishing (CMP) compositions (also known as slurries or formulations), CMP methods, and CMP systems that use colloidally stable amphiphilic abrasive particle dispersions containing the amphiphilic abrasive particles.

[0039] The present invention provides colloidally stable amphiphilic abrasive dispersions for use in CMP compositions. Colloidally stable means that the abrasive particles of the present invention do not gel, precipitate, or exhibit a change in mean particle size (MPS as measured by DLS) of more than 10% within 30 days when stored at room temperature as a dispersion (20% solids by weight) in a solvent, including but not limited to water, at a pH such that the zeta potential is either greater than +25 mV or less than -25 mV; the aqueous solvent includes but is not limited to alcohols, ethers, ketones, and mixtures thereof.

[0040] The amphiphilic abrasive particles in the dispersion have a highly non-polar and inert surface relative to silicon oxide, while being colloidally stable. Colloidal stability refers to solvent dispersibility, including but not limited to water, and water-soluble solvents, including but not limited to alcohols, ethers, ketones, and mixtures thereof.

[0041] The abrasive particles have silanol groups converted with inert silanes, and therefore have low silanol density and positive charge in the acidic low pH range, providing high selectivity, especially for tungsten CMP (W CMP) applications.

[0042] These and other advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

[0043] Abrasive particles:

[0044] Colloidally stable amphiphilic abrasive particles are obtained through a two-step surface modification or treatment process in the present invention.

[0045] Base or unmodified abrasive particles such as silica (leftmost circle) have a very hydrophilic surface covered with Si-OH (silanol) and Si-O-Si- (siloxane) groups, which can carry a positive or negative charge depending on the pH.

[0046] For example, a first-step surface modification using a first-step surface modifier such as an aminosilane that covalently reacts with Si-OH groups on the surface of the base abrasive particle adds hydrophilic (or polar) and / or charged groups to the surface of the abrasive particle.

[0047] Furthermore, the first-step surface modification can also result in the formation of a continuous polysiloxane crosslink or network shell around the base abrasive particles, depending on the amount of first-step surface modifier applied and due to reactions between the first-step surface modifiers.

[0048] Thus, the first step of surface modification can result in either a partial surface modification, leaving a portion of the base abrasive surface unmodified, or the formation of a polysiloxane crosslinked shell that covers and modifies the entire surface of the base abrasive particle, as shown in the illustration below. [ka]

[0049] Illustration A shows a surface modification in which a crosslinked shell (such as a polyorganosiloxane shell) is formed around the base abrasive particle by reaction between the first step surface modifiers themselves, forming a covalently bonded polymeric crosslinked shell around the base abrasive particle after the first modification step. This shell still contains residual silanol groups on the surface that can react with a second surface modifier in a second modification step.

[0050] Illustration B shows a surface modification in which only a portion of the original silanol groups from a portion of the base abrasive particle surface react with the first-step surface modifier, leaving some of the original silanol groups unreacted. These silanol groups, and potentially new silanol groups created by surface modification step 1, can then react with the second-step surface modifier in modification step 2.

[0051] In practice, if the surface modification in the first step (Step 1) is incomplete due to either cost or steric reasons, there will be many residual Si-OH groups (remaining Si-OH groups) on the surface after modification. Furthermore, it is almost impossible for the modified silane to cover access to the polar Si-O-Si network. Therefore, there may be enough "polarity" on the surface to promote undesirable interactions with polar silicon oxide, even though the silicon oxide should not be attacked by the abrasive particles.

[0052] In a second surface modification step (Step 2), the residual Si—OH groups may be modified with a second-step surface modifier, which is typically a small, highly hydrophobic reactant, to add hydrophobic (or non-polar) groups to the surface of the abrasive particle.

[0053] Surface modification of silica and other oxides with only small hydrophobic molecules such as trimethylchlorosilane is used to create trickling (anti-caking) aids for laser printer toners or hydrophobic pigments. The modified silica is rendered completely hydrophobic by the modification, making it nearly impossible to maintain in a colloidally stable dispersion in water. In fact, these treatments are also used to impart water repellency to particles.

[0054] Also, when silica is modified in aqueous dispersion with small hydrophobic molecules such as trimethylchlorosilane, the colloidal dispersion is likely to become unstable and the silica will aggregate and eventually precipitate.

[0055] The present invention overcomes all of these adverse effects, as explained below.

[0056] In the present invention, the first step surface modification permanently introduces hydrophilic (polar) groups (which may be ionic and / or non-ionic) onto the surface of the base particle so that it has good compatibility with water and high colloidal stability, especially when the first step surface modification includes charged groups that cause like-charged particles to repel each other.

[0057] After the first surface modification step, the abrasive is prepared for the second modification step. It is preferable to use small molecules in the second modification step so that they can reach all accessible silanol groups, effectively occupy space on the abrasive surface, and protect a significant portion of the underlying hydrophilic surface moieties. It is preferable that a large proportion (e.g., more than 50%, more than 60%, or more than 70%) of the accessible silanol groups and other polar moieties on the surface of the abrasive be converted or protected.

[0058] The hydrophilic (polar) groups in the first modification step are typically attached to alkyl spacers with a certain length (typically 3 or more C atoms) and exhibit sufficient mobility so that they cannot be completely covered by the second surface modification step and maintain high colloidal stability.

[0059] After the second-step surface modification, the majority of accessible silanol groups on the surface of the base silica are either converted by reaction with the first-step surface modifier used, such as silane, or protected from interaction with the surface to be planarized. Thus, the surface properties of the amphiphilic abrasive can be completely altered to become a defined or balanced mixture of the introduced hydrophilic moieties (from the first surface treatment) and hydrophobic moieties (from the second surface treatment), essentially free of the original hydrophilic moieties that could undesirably interact with the TEOS surface in, for example, a CMP application.

[0060] The total amount of the first step surface modifier and the second step surface modifier is in the range of 0.01 to 1.0 mmol / g (mass of the abrasive calculated as dry substance), 0.025 to 0.8 mmol / g, 0.05 to 0.5 mmol / g, or 0.1 to 0.4 mmol / g.

[0061] Because there are distinct hydrophobic and hydrophilic portions that extend across the entire surface of the two-step modified abrasive particles, the two-step modified abrasive particles can be referred to as amphiphilic (mixed hydrophilic and hydrophobic) particles. Amphiphiles typically have the property of being compatible with both polar and non-polar liquids and can function as emulsifiers. Therefore, it is believed that these amphiphilic abrasive particles may also be advantageous in applications such as spin-on carbon CMP and other CMP applications where non-polar components play a role.

[0062] By selecting the ratio of the hydrophilic (polar) portion from the first modification step and the hydrophobic (non-polar) portion from the second modification step, the interaction between the amphiphilic abrasive particles of the present invention and the surface to be preserved during CMP can be reduced to a very low level, thus providing polishing selectivity, for example, excellent "stop-on silicon oxide" performance in W-CMP.The amphiphilic abrasive particles of the present invention also have outstanding colloidal stability.

[0063] The ratio of hydrophilic (polar) moieties from the first modification step to hydrophobic (non-polar) moieties from the second modification step can be 1.00:0.01 to 1.00:10.00, 1.00:0.25 to 1.00:5.00, 1.00:0.30 to 1.00:3.00, 1.00:0.40 to 1.00:2.50, or 1.00:0.50 to 1.00:2.00.

[0064] Further details regarding the process for obtaining colloidally stable amphiphilic abrasive particles are described.

[0065] The starting base or unmodified abrasive particles (or abrasives) have reactive M-OH groups on their surface, where M is a metal or metalloid, including, but not limited to, Si, Ce, Al, Zr, and hybrids / mixtures of metals and / or metalloids. Examples of base or unmodified abrasive particles include, but are not limited to, silica, ceria, hybrids of silica and ceria (ceria modified silica, or silica modified ceria), zirconium silicate, carbides, or nitrides.

[0066] Preferred base abrasives are SiO2-containing abrasives such as pure silica, doped silica, or multicomponent silicates.

[0067] A more preferred base abrasive is non-spherical colloidal silica as described in WO 2022 / 226471.

[0068] The base abrasive can be provided in dispersed, agglomerated, or dry form, so long as it is treated as described by the two surface modification steps to obtain a colloidally stable amphiphilic abrasive dispersion.

[0069] Prior to the first surface modification step, the base abrasive should be dispersed in a suitable solvent (or mixture) and substantially crushed to the desired size distribution, typically with at least one dimension less than 500 nm, preferably less than 200 nm, and more preferably less than 150 nm, prior to surface modification.

[0070] The base particles must be dispersed in a solvent or solvent mixture that allows the first step surface modification and the second step surface modification to occur in a colloidally stable state. The solvent composition can be and may be changed after the first step and before and / or after the second step for smooth processing and colloidally stable amphiphilic abrasive dispersion.

[0071] Typical preferred solvent mixtures are water / alcohol mixtures in various ratios that dissolve the surface modifier, with ethanol being the most preferred alcohol.

[0072] Other possible organic solvents that can be used in the mixture with water are ketones, esters, ethers, glycols, and alcohols. Examples of suitable organic solvents are acetone, diethyl ether, propylene glycol dimethyl ether, propylene glycol monoacetyl ester, isopropanol, n-propanol, propylene glycol monomethyl ether.

[0073] Pure water is possible but not preferred as a solvent for the modification steps, especially for the second modification step, because the hydrophobic modifier does not dissolve or disperse easily in water, which can lead to longer process times and non-uniform results.

[0074] At the latest after the second step of surface modification, it is preferred to remove the non-volatile organic components from the abrasive dispersion, maintaining essentially water as the only dispersant in the final product.

[0075] The surface modification can be carried out at any suitable pH, depending on the nature of the base abrasive and the reactants.

[0076] Typically, alkaline conditions are preferred to promote the reaction between the surface groups of the abrasive particles and the reactant, although good results can also be obtained under acidic conditions.

[0077] It is preferred to use a pH adjuster that can be removed from the reaction mixture, for example by applying a vacuum, or that is a desired component of the subsequently formulated CMP slurry. Typical preferred pH adjusters are HNO or NH.

[0078] A catalyst may also be used to facilitate the reaction. Suitable catalysts include, but are not limited to, fluoride ion, or metal salts or metal alkoxides such as titanium isopropoxide.

[0079] The first-step surface modifier can be any reactant capable of forming a covalent bond with the surface M-OH groups of the unmodified base abrasive, where the M-OH groups are selected from the group including, but not limited to, metals or metalloids, including Si, Ce, Al, Zr, and hybrids and / or mixtures of metals and metalloids. The M-OH groups function as linking groups with M as the linking atom, where M is the atom that covalently links or bonds the abrasive surface to the hydrophilic moiety.

[0080] The first step surface modifier can be a single reactant or a mixture of reactants.

[0081] The first step surface modifier is a hydrophilic modifier that contains hydrophilic groups that can be covalently attached to a linking group, preferably Si, by alkyl and / or aryl groups that may also contain heteroatoms.

[0082] The hydrophilic group may be anionic, cationic, zwitterionic (inner salt), or nonionic in nature. The hydrophilic group may be anionic, cationic, or nonionic depending on the pH of the solvent. Preferred hydrophilic groups are N-containing groups such as amine, amino, ammonium, or alkylammonium groups.

[0083] Examples of hydrophilic groups include, but are not limited to, amines, substituted amines, amino groups, ammonium and substituted ammonium groups, sulfonium, phosphonium, sulfate, sulfonate, phosphate, hydroxy, epoxy, carboxy, ether, or polyether groups.

[0084] Examples of first-step surface modifiers include, but are not limited to, silanes containing a hydrophilic group and at least one reactive group capable of forming a covalent bond with an abrasive surface group. Examples include aminopolyether silanes and betaine-type silanes.

[0085] There can be two or more hydrophilic groups attached to one linking group that reacts with the abrasive surface. The two or more hydrophilic groups can be of the same type or different types, for example, anionic + cationic, anionic + nonionic, or cationic + nonionic. The first-step surface modifier, which is a hydrophilic surface modifier, has at least one reactive group that can form a covalent bond with an abrasive surface group.

[0086] The reactive group of the surface modifier can be any group that is capable of bond cleavage under process conditions, thereby facilitating a covalent bond between the abrasive surface and the modifier, or that can react directly with groups on the abrasive surface.

[0087] Typical reactive groups include, but are not limited to, Si-alkoxide, Si-halide (preferably chloride), oximate, acetate, or Si-hydroxide. Preferred examples are silicon methoxide and silicon ethoxide.

[0088] Preferred first step surface modifiers are 3-aminopropyl derivatives of ethoxysilane or methoxysilane, such as 3-aminopropylmethyldimethoxysilane.

[0089] The first-step surface modifier can be used in any mixture with other functional or non-functional reactants, such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, or combinations thereof. The ratio of the first-step modifier to the functional or non-functional reactant can range from 9.9:1 to 0.1:9.9, preferably 9:1 to 1:9, but is not limited to these.

[0090] After the first modification step, a one-step modified abrasive particle is obtained. The surface of the one-step modified abrasive particle contains reactive groups of X-OH groups, where X in the reactive X-OH groups includes, but is not limited to, Si, Ce, Al, Zr, C, P, N, and hybrids and / or mixtures thereof. The X-OH groups function as linking groups with X as the linking atom. Here, the linking atom is an atom that covalently connects or bonds the abrasive surface to the hydrophobic moiety.

[0091] Second-step surface modifiers include, but are not limited to, reactants capable of forming covalent bonds with the surface X-OH groups of the one-step modified abrasive particles.

[0092] The second step surface modifier can be a single reactant or a mixture of reactants.

[0093] The second step surface modifier is a hydrophobic modifier that contains hydrophobic groups.

[0094] The reactive group of the second surface modifier relative to the surface of the abrasive can be any group that can be cleaved under process conditions, thereby facilitating a covalent bond between the one-step modified abrasive particle surface and the second-step surface modifier, or that can react directly with a group on the one-step modified abrasive particle surface.

[0095] Examples of typical reactive groups include, but are not limited to, Si-alkoxide, Si-halide (chloride is preferred), oximate, acetate, or Si-hydroxide, silazane, silanoate (e.g., KOSi(CH3)3), or siloxane. Preferred examples are silicon methoxide, silicon ethoxide, and silazane.

[0096] Second step surface modifiers typically do not carry functional groups on their alkyl or aryl groups.

[0097] The second-step surface modifier comprises at least two alkyl and / or aryl groups, preferably three alkyl and / or aryl groups, covalently bonded to a linking atom X (e.g., a silicon atom). The alkyl groups have a length of less than 20 C atoms, preferably less than 10 C atoms, more preferably less than 4 C atoms. The aryl groups may carry aliphatic substituents and have a total of less than 20 C atoms, preferably less than 10 C atoms, more preferably less than 8 C atoms. Examples of linking atoms may be Si, Ce, Al, Zr, C, P, and N atoms.

[0098] Examples of second-step surface modifiers include, but are not limited to, silanes containing a hydrophobic group, at least one reactive group capable of forming a covalent bond with the one-step modified abrasive particle surface group.

[0099] Examples of second step surface modifiers include, but are not limited to, trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium trimethylsilanoate, triethylmethoxysilane, and mixtures thereof.

[0100] For the second-step surface modifier, it is preferable to use a short-chain small molecule with only one reactive group, such as trimethylmethoxysilane, trimethylethoxysilane, or a mixture thereof. If the reactant from the second-step surface modifier does not have a chance to react with the surface of the abrasive, but the two reactants react with each other, hexamethyldisiloxane, an organic solvent with a sufficiently low boiling point, is formed, and this by-product can be easily removed by distillation. Therefore, even a large excess of reactant can be handled in the reaction without the problem of undesired by-products and the accumulation of unreacted reactants.

[0101] The first and second step surface modifications can be performed completely separately, with indefinite pauses and / or other operations in between, such as distillation, concentration, filtration, purification, ion exchange, and the like.

[0102] The first and second step surface modifications can be carried out under the same or different conditions, such as at different pHs, in different solvent mixtures, at different temperatures, with different catalysts, and for different reaction times. Each modification step is a stand-alone process that can and should be carried out under conditions that are optimal for the individual reaction.

[0103] The first and second step surface modifications can also be performed immediately one after the other without any change in pH, solvent, temperature, or catalyst.

[0104] It is preferable to carry out the first and second step modifications one after the other, and not to start the second step surface modification before it is confirmed that the first step surface modification is nearly complete, for example, by checking with NMR or IR measurement. This is to ensure that after the first step surface modification, the abrasive surface is sufficiently hydrophilic to remain stable during the reaction with the hydrophobic second modifier.

[0105] After each surface modification step there may be an optional ageing step at a defined temperature between 0° C. and the boiling point of the solvent mixture used.

[0106] After the second surface modification, an optional aging step to ensure reaction completion (after which the volatile organic components of the reaction mixture are removed and optionally replaced with water) is preferred.

[0107] This can be done by any suitable process, such as distillation or membrane filtration. Preferably, the total non-volatile solids content of the reaction mixture is adjusted to 10-50% solids, more preferably 20-40% solids, and most preferably 30-40% solids.

[0108] After the second surface modification, further modifications can be performed, such as filtration, classification, ion exchange, addition of other compounds, etc. This can be done before or after removal of volatile organic compounds.

[0109] The second surface modification is preferably carried out to the extent that the colloidal stability of the abrasive dispersion is not affected and a minimum silicon oxide removal rate is achieved.

[0110] There is a minimum total amount of surface modifier (first and second steps) to provide good removal rate and selectivity.

[0111] A minimum content of hydrophilic modifier in the first modification is required to ensure colloidal stability.

[0112] The minimum hydrophobic modifier content in the second step is determined by high or maximum selectivity: too much hydrophobic modifier will cause aggregation.

[0113] The amphiphilic abrasive particles of the present invention are colloidally stable amphiphilic abrasive particles having a surface comprising hydrophilic and hydrophobic moieties. By way of example, the hydrophilic moieties can be amino groups and the hydrophobic moieties can be trimethylsilane groups.

[0114] The colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic to hydrophobic moieties in the range of 1.00:0.01 to 1.00:10.00, 1.00:0.25 to 1.00:5.00, 1.00:0.30 to 1.00:3.00, 1.00:0.40 to 1.00:2.50, or 1.00:0.50 to 1.00:2.00.

[0115] A colloidally stable amphiphilic abrasive dispersion refers to amphiphilic abrasive particles dispersed in a solvent, including water, having any size distribution, including but not limited to unimodal, bimodal, or multimodal, any shape, including but not limited to spherical, elongated, or branched, and a diameter in the range of 1-500 nm, 2-300 nm, 5-200 nm, 10-150 nm, or 20-100 nm.

[0116] Thus, provided herein are colloidally stable amphiphilic abrasive particles, wherein the surface of the colloidally stable amphiphilic abrasive particles comprises hydrophilic and hydrophobic moieties, and the colloidally stable amphiphilic abrasive particles are highly non-polar.

[0117] wherein the hydrophilic group is at least one selected from the group consisting of amines and substituted amines; amino groups; ammonium; N-containing groups selected from the group consisting of ammonium groups and substituted ammonium groups, including but not limited to alkylammonium groups containing alkyls having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups; preferably, each of the hydrophilic moieties containing an N-containing group independently contains at least one selected from the group consisting of alkyls having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms; aryls having less than 20 C atoms, less than 10 C atoms, or less than 8 C atoms; and combinations thereof.

[0118] Additionally, two or more hydrophilic moieties and / or two or more hydrophobic moieties may be attached to a linking atom selected from the group consisting of Si atoms, Ce atoms, Al atoms, Zr atoms, C atoms, P atoms, and N atoms, which link or bond the hydrophilic moieties and / or hydrophobic moieties to the surface of each colloidally stable amphiphilic abrasive particle via a covalent bond.

[0119] The colloidally stable amphiphilic abrasive particles have a hydrophilic portion that is a silane having an amino group and a hydrophobic portion that is a trimethylsilane group, and the colloidally stable amphiphilic abrasive particles have a surface that is highly non-polar and inert to silicon oxide.

[0120] The colloidally stable amphiphilic abrasive particles have a ratio of hydrophilic to hydrophobic moieties in the range of 1.00:0.01 to 1.00:10.00, 1.00:0.25 to 1.00:5.00, 1.00:0.30 to 1.00:3.00, 1.00:0.40 to 1.00:2.50, or 1.00:0.50 to 1.00:2.00.

[0121] The surface of each colloidally stable amphiphilic abrasive particle can be a covalently bonded polymeric crosslinked shell, such as a polyorganosiloxane crosslinked shell.

[0122] Provided herein is a method for making colloidally stable amphiphilic abrasive particles, the method comprising: a. providing base abrasive particles having reactive M-OH groups on their surfaces, the base abrasive particles being dispersed in a solvent; b. modifying the surface of the base abrasive particles with a first-step surface modifier having at least one hydrophilic group and one smallest first reactive group capable of forming a covalent bond with or directly reacting with the reactive M-OH group to obtain a one-step modified abrasive particle; c. modifying the surface of the one-step modified abrasive particle with a second-step surface modifier having at least one hydrophobic group and at least one second reactive group capable of forming a covalent bond with or reacting directly with the X-OH group on the surface of the one-step modified abrasive particle to obtain an amphiphilic abrasive particle; During the ceremony, M in the reactive M-OH group is selected from the group including, but not limited to, metals or metalloids, including Si, Ce, Al, Zr, and hybrids and / or mixtures of metals and metalloids; X in the reactive X-OH group is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and / or mixtures thereof; The solvent is selected from the group consisting of water, alcohol, preferably ethanol, ketones, esters, ethers, glycols, and combinations thereof, preferably a combination of water and alcohol.

[0123] The at least one first reactive group or the at least one second reactive group is independently selected from the group consisting of silicon alkoxides, silicon halides (preferably chlorides), oximates, acetates, silicon hydroxides, and combinations thereof, preferably silicon methoxides and silicon ethoxides.

[0124] The first step surface modifier is selected from silanes having at least one hydrophilic group, and the second step surface modifier is selected from silanes having at least one hydrophobic group.

[0125] The first step surface modifier comprises at least one hydrophilic group, preferably an N-containing group selected from the group comprising amines and substituted amines; amino groups, ammonium; alkylammonium groups including alkyls with less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms; sulfonium; phosphonium; sulfate; sulfonate; phosphate; hydroxy; epoxy; carboxy; ether; polyether; or polyether groups, including but not limited to, an N-containing group selected from the group comprising amines, amino groups, ammonium, and alkylammonium groups.

[0126] A crosslinked shell (a covalently bonded polymer shell, such as a polyorganosiloxane shell) can be formed around the base abrasive particle in step b by reaction between the first-step surface modifiers themselves, and this shell still contains residual X-OH groups on the surface that can react with the second surface modifier in step c.

[0127] The second step surface modifier comprises at least one hydrophobic group including, but not limited to, an alkyl group having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms; and an aryl group having less than 20 C atoms, less than 10 C atoms, or less than 8 C atoms.

[0128] The second step surface modifier comprises at least two, preferably at least three hydrophobic groups including alkyl having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms; aryl having less than 20 C atoms, less than 10 C atoms, or less than 8 C atoms; and combinations thereof.

[0129] The total amount of the first step surface modifier and the second step surface modifier is in the range of 0.01 to 1.0 mmol / g (mass of the abrasive calculated as dry substance), 0.025 to 0.8 mmol / g, 0.05 to 0.5 mmol / g, or 0.1 to 0.4 mmol / g.

[0130] The method further comprises, after step c, step d, retaining water as the only dispersing liquid after the surface modification of the second step.

[0131] Further provided herein is a CMP polishing composition comprising the above-described colloidally stable amphiphilic abrasive particles dispersed in water, and a water-soluble solvent including, but not limited to, alcohols, ethers, ketones, and mixtures thereof.

[0132] The CMP polishing composition optionally comprises: Organic and inorganic salts as colloid stabilizers; catalysts, including but not limited to fluoride ions, metal salts, or metal alkoxides such as titanium isopropoxide; Acid / base pH buffers; Biocides; oxidizing agents; catalyst; chelating agents; dishing and erosion inhibitors; and The composition may include at least one of a corrosion inhibitor.

[0133] Additionally provided is a method of chemical mechanical polishing (CMP) a substrate having at least one surface comprising tungsten using the above-described chemical mechanical polishing (CMP) composition.

[0134] Specifically, CMP compositions using colloidally stable amphiphilic abrasive particle dispersions provide high removal rates of tungsten (W), suppressed removal rates of TEOS, and therefore excellent W:TEOS selectivity for chemical mechanical planarization of tungsten surfaces (i.e., W CMP), especially at acidic low pH.

[0135] CMP method In the examples below, CMP experiments were performed using the procedures and experimental conditions set out below.

[0136] Glossary component Silicon oxide films by chemical vapor deposition (CVD) using TEOS: tetraethyl orthosilicate as a precursor

[0137] Wt%: Weight percent (of listed ingredients)

[0138] Removal Rate (RR) = (film thickness before polishing - film thickness after polishing) / polishing time.

[0139] Polishing pad: A polishing pad (IC1010) supplied by DOW, Inc. was used during CMP.

[0140] Conditioning disc: 3M A122 disc provided by 3M was used.

[0141] Parameters General Å or ​​A: Angstrom - unit of length

[0142] BP: Back pressure, unit is psi

[0143] CMP: Chemical mechanical planarization = chemical mechanical polishing

[0144] CS: Carrier speed

[0145] DF: Down force: Pressure applied during CMP, unit: psi

[0146] min:minutes

[0147] mL: milliliter

[0148] mV: millivolt

[0149] psi: pounds per square inch

[0150] PS: Polishing tool platen rotation speed, in rpm (revolutions per minute)

[0151] SF: composition flow rate, mL / min

[0152] Wt%: Weight percent (of listed ingredients)

[0153] W: TEOS selectivity: (W removal rate) / (TEOS removal rate)

[0154] HDP: TEOS deposited by high density plasma

[0155] TEOS or HDP removal rate: The TEOS or HDP removal rate measured at a given down pressure.

[0156] Agglomeration ratio: The agglomeration ratio is a descriptor of the shape of non-spherical particles. It is the quotient of the secondary particle size measured by DLS and the calculated primary particle size obtained from the BET surface area as commonly known in the art. Agglomeration ratio = secondary particle size / primary particle size Primary particle diameter=2727 / BET specific surface area

[0157] measurement The films were measured using a ResMap CDE Model 168 from Creative Design Engineering, Inc. (20565 Alves Dr., Cupertino, CA 95014). The ResMap tool is a four-point probe sheet resistance tool. A 49-point diameter scan was performed on the film, excluding 5 mm from the edges.

[0158] CMP Tools The CMP tools used were a 200 mm Mirra or a 300 mm Reflexion manufactured by Applied Materials, 3050 Bowers Avenue, Santa Clara, California, 95054. An IC1000 pad supplied by DOW, Inc., 451 Bellevue Rd., Newark, DE 19713, was used on platen 1 for blanket and patterned wafer studies.

[0159] The IK4250UH pads or other pads were conditioned and broken in for 18 minutes. The conditioner downforce was 7 pounds. To verify tool settings and pad break-in, two tungsten monitors and two TEOS monitors were polished with Versum® STI2305 composition supplied by Versum Materials Inc. under reference conditions.

[0160] All polishing data in the following examples was generated on a Mirra polisher using an IC1010 pad with a polishing downforce of 2.5 psi.

[0161] wafer Polishing experiments were performed using PECVD or LPCVD or HD TEOS wafers. These blanket wafers were purchased from Silicon Valley Microelectronics (2985 Kifer Rd., Santa Clara, CA 95051). [Example]

[0162] Abrasive modification experiment Example 1 (Comparative Example) Synthesis of polyaminoorganosiloxane-modified elongated silica nanoparticles In a 2,000 mL four-neck flask equipped with a stirrer and a reflux condenser, a suspension of silica nanoparticles in water (911.50 g, 978.49 mmol SiO2, elongated shape, aggregation ratio: 2.86, diameter of 95.8 nm as measured by DLS, pH 10.5) was heated with stirring to 70 °C. With continued stirring, a mixture of (3-aminopropyl)dimethoxymethylsilane (1.22 mL, 7.06 mmol), tetraethoxysilane (14.07 mL, 63.51 mmol), and ethanol (140.57 mL, 2410.57 mmol, 2.46 equiv.) was added within 6 h.

[0163] The volatile organic solvent was exchanged for water by rotary evaporation, and the resulting suspension of polyaminoorganosiloxane-modified elongated silica particles was adjusted to pH 2.5 with HNO3 and finally concentrated to 20 wt% solids.

[0164] The yield was a suspension of colloidally stable, one-step modified elongated silica nanoparticles with a diameter of 97.1 nm (measured by DLS).

[0165] Example 2 In a 2,000 mL four-neck flask equipped with a stirrer and a reflux condenser, a suspension of silica nanoparticles in water (911.50 g, 978.49 mmol SiO2, elongated shape, aggregation ratio: 2.86, diameter of 95.8 nm as measured by DLS, pH 10.5) was heated with stirring to 70 °C. With continued stirring, a mixture of (3-aminopropyl)dimethoxymethylsilane (1.22 mL, 7.06 mmol), tetraethoxysilane (14.07 mL, 63.51 mmol), and ethanol (140.57 mL, 2410.57 mmol, 2.46 equiv.) was added within 6 h.

[0166] In the next step, a mixture of trimethylmethoxysilane (99%, 0.975 mL, 7.055 mmol) and ethanol (16.75 mL, 287.18 mmol) was added over 6 hours with stirring at 70° C., followed by stirring at room temperature for 12 hours.

[0167] The volatile organic solvent was exchanged for water by rotary evaporation, and the resulting suspension of polyaminoorganosiloxane-modified elongated silica particles was adjusted to pH 2.5 with HNO3 and finally concentrated to 20 wt% solids.

[0168] The result was a suspension of colloidally stable, two-step modified elongated silica nanoparticles with a diameter of 98.1 nm (measured by DLS).

[0169] Example 3 In a 2,000 mL four-neck flask equipped with a stirrer and a reflux condenser, a suspension of silica nanoparticles in water (911.50 g, 978.49 mmol SiO2, elongated shape, aggregation ratio: 2.86, diameter 95.8 nm as measured by DLS, pH 10.5) was heated with stirring to 70 °C. With continued stirring, a mixture of (3-aminopropyl)dimethoxymethylsilane (1.22 mL, 7.06 mmol), tetraethoxysilane (14.07 mL, 63.51 mmol), and ethanol (140.57 mL, 2410.57 mmol, 2.46 equiv.) was added within 6 h.

[0170] In the next step, a mixture of trimethylmethoxysilane (99%, (1.95 mL, 14.11 mmol)) and ethanol (16.75 mL, 287.18 mmol) was added over 6 hours with stirring at 70° C., and then stirred at room temperature for 12 hours.

[0171] The volatile organic solvent was exchanged for water by rotary evaporation, and the resulting suspension of polyaminoorganosiloxane-modified elongated silica particles was adjusted to pH 2.5 with HNO3 and finally concentrated to 20 wt% solids.

[0172] The result was a suspension of colloidally stable, two-step modified elongated silica nanoparticles with a diameter of 99.7 nm (measured by DLS).

[0173] Example 4 (Comparative Example) Synthesis of polyaminoorganosiloxane-modified elongated silica nanoparticles In a 2,000 mL four-neck flask equipped with a stirrer and reflux condenser, a suspension of silica nanoparticles in water (564.97 g, 1664.33 mmol SiO2, elongated shape, aggregation ratio 2.71, diameter 91.6 nm as measured by DLS, pH 10.5) was heated with stirring to 70 °C. With continued stirring, a mixture of 3-aminopropyltriethoxysilane (5.59 mL, 24.00 mmol), tetraethoxysilane (47.87 mL, 216.00 mmol), and ethanol (468.07 mL, 8.03 mol) was added with stirring over 12 h.

[0174] The volatile organic solvent was exchanged for water by rotary evaporation, and the resulting suspension of polyaminoorganosiloxane-modified elongated silica particles was adjusted to pH 2.5 with HNO3 and finally concentrated to 20 wt% solids.

[0175] The result was a suspension of colloidally stable, one-step modified elongated silica nanoparticles with a diameter of 94.5 nm (measured by DLS).

[0176] Example 5 In a 2,000 mL four-neck flask equipped with a stirrer and reflux condenser, a suspension of silica nanoparticles in water (564.97 g, 1664.33 mmol SiO2, elongated shape, aggregation ratio 2.71, diameter 91.6 nm as measured by DLS, pH 10.5) was heated with stirring to 70 °C. With continued stirring, a mixture of 3-aminopropyltriethoxysilane (5.59 mL, 24.00 mmol), tetraethoxysilane (47.87 mL, 216.00 mmol), and ethanol (468.07 mL, 8.03 mol) was added with stirring over 12 h.

[0177] In the next step, a mixture of trimethylmethoxysilane (99%, (1.658 mL, 12.00 mmol) and ethanol (16.75 mL, 287.18 mmol) was added over 6 hours with stirring at 70° C., and then stirred at room temperature for 12 hours.

[0178] The volatile organic solvent was exchanged for water by rotary evaporation, and the resulting suspension of polyaminoorganosiloxane-modified elongated silica particles was adjusted to pH 2.5 with HNO3 and finally concentrated to 20 wt% solids.

[0179] The result was a suspension of colloidally stable, two-step modified elongated silica nanoparticles with a diameter of 96.1 nm (measured by DLS).

[0180] Example 6 In a 2,000 mL four-neck flask equipped with a stirrer and reflux condenser, a silica nanoparticle suspension (564.97 g, 1664.33 mmol SiO2, elongated shape, aggregation ratio 2.71, diameter 91.6 nm as measured by DLS, pH 10.5) was heated with stirring to 70 °C. With continued stirring, a mixture of 3-aminopropyltriethoxysilane (5.59 mL, 24.00 mmol), tetraethoxysilane (47.87 mL, 216.00 mmol), and ethanol (468.07 mL, 8.03 mol) was added with stirring over 12 h.

[0181] In the next step, a mixture of trimethylmethoxysilane (99%, (1.658 mL, 36.00 mmol) and ethanol (50.25 mL, 861.54 mmol) was added over 12 hours with stirring at 70° C., followed by stirring at room temperature for 12 hours.

[0182] The volatile organic solvent was exchanged for water by rotary evaporation, and the resulting suspension of polyaminoorganosiloxane-modified elongated silica particles was adjusted to pH 2.5 with HNO3 and finally concentrated to 20 wt% solids.

[0183] The result was a suspension of colloidally stable, two-step modified elongated silica nanoparticles with a diameter of 98.6 nm (measured by DLS).

[0184] Example 7 (Comparative Example) Synthesis of polyaminoorganosiloxane-modified elongated silica nanoparticles In a 1,000 mL four-neck flask equipped with a stirrer and reflux condenser, a suspension of silica nanoparticles in water (482.43 g, 1170 mmol SiO2, elongated shape, aggregation ratio 2.98, diameter 86.2 nm as measured by DLS, pH 4.3) was heated to 70 °C with stirring.

[0185] With continuous stirring, two streams of reactants were added simultaneously to the flask within 1 h by precision pumps, and the streams were mixed in a T-connector just before reaching the flask.

[0186] Stream 1 consisted of (3-aminopropyl)dimethoxymethylsilane (5.81 mL, 33.60 mmol) dissolved in 95 mL of methanol. Stream 2 consisted of nitric acid 65% (2.58 mL, 36.96 mmol) dissolved in 98.2 mL of methanol.

[0187] After addition of the reactants, the mixture of the two streams was stirred at 70° C. for 2 hours, then the volatile reaction products were removed by rotary evaporation and the solids content was adjusted to 20% by weight by the addition of water.

[0188] The result was a suspension of colloidally stable, one-step modified elongated silica nanoparticles with a diameter of 87.5 nm (measured by DLS).

[0189] Example 8 In a 1,000 mL four-neck flask equipped with a stirrer and reflux condenser, a suspension of silica nanoparticles in water (482.43 g, 1170 mmol SiO2, elongated shape, aggregation ratio 2.98, diameter 86.2 nm as measured by DLS, pH 4.3) was heated to 70 °C with stirring.

[0190] With continuous stirring, the two streams were simultaneously added to the flask within 1 h by precision pumps, and the streams were mixed in a T-connector just before reaching the flask.

[0191] Stream 1 consisted of (3-aminopropyl)dimethoxymethylsilane (5.81 mL, 33.60 mmol) dissolved in 95 mL of methanol. Stream 2 consisted of nitric acid 65% (2.58 mL, 36.96 mmol) dissolved in 98.2 mL of methanol.

[0192] After the two streams were mixed, trimethylmethoxysilane (3.47 mL, 25.2 mmol) dissolved in 62.9 mL of methanol was added to the mixture of the two streams over a period of 1.5 hours.

[0193] The final mixture was stirred at 70° C. for an additional 12 hours, then the volatile reaction products were removed by rotary evaporation and the solids content was adjusted to 20% by weight by the addition of water.

[0194] The result was a suspension of colloidally stable, two-step modified elongated silica nanoparticles with a diameter of 87.9 nm (measured by DLS).

[0195] Example 9 (Comparative Example) In a 1,000 mL four-neck flask equipped with a stirrer and reflux condenser, a suspension of silica nanoparticles in water (482.43 g, 1170 mmol SiO2, elongated shape, aggregation ratio 2.98, diameter 86.2 nm as measured by DLS, pH 10.5) was heated to 70 °C with stirring.

[0196] Trimethylmethoxysilane (3.47 mL, 25.2 mmol), dissolved in 62.9 mL of methanol, was added to the reaction mixture over 1.5 hours.

[0197] The mixture was stirred at 70° C. for an additional 12 hours, and then the volatile reaction products were removed by rotary evaporation.

[0198] The result was a highly turbid dispersion of agglomerated silica in water that lacked colloidal stability and could not be used in CMP slurry formulations.

[0199] Chemical Mechanical Planarization (CMP) Experiments The modified silica nanoparticle suspension obtained above was used to formulate a W-CMP slurry containing 0.1 wt% abrasive (PL-2C), 0.01 wt% ferric nitrate (iron(III) nitrate), 0.08 wt% malonic acid, 0.02 wt% 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 2.0 wt% hydrogen peroxide, and 0.1 wt% glycine in water, with the pH adjusted to 2.3 with nitric acid.

[0200] The slurries and removal rates are shown in Table 1. [Table 1] * APDMS: 3-aminopropyl)dimethoxymethylsilane, ** APTES: 3-aminopropyltriethoxysilane, *** TMMOS: Trimethylmethoxysilane.

[0201] As shown in Table 1, slurries using the two-step modified abrasive particles were very effective in suppressing the TEOS removal rate while maintaining or increasing W removal, thus increasing the W:TEOS RR selectivity.

[0202] The embodiments of the invention listed above, including the examples, are illustrative of the many embodiments that can be made from the present invention. It is contemplated that many other configurations of the process may be used and that the materials used in the process may be selected from many materials other than those specifically disclosed.

Claims

1. Colloidally stable amphiphilic abrasive particles, wherein the surface of each colloidally stable amphiphilic abrasive particle comprises hydrophilic and hydrophobic moieties.

2. 2. The colloidally stable amphiphilic abrasive particle of claim 1, wherein each of the hydrophilic moieties independently comprises at least one selected from the group consisting of amines and substituted amines, amino groups, ammonium, N-containing groups selected from the group including ammonium groups and substituted ammonium groups, sulfonium, phosphonium, sulfate, sulfonate, phosphate, hydroxy, epoxy, carboxy, ether, polyether, and polyether groups.

3. 3. The colloidally stable amphiphilic abrasive particle of claim 1, wherein each of the hydrophilic moieties independently comprises at least one selected from the group consisting of amine, ammonium, and alkylammonium groups, including alkyls having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms.

4. The colloidally stable amphiphilic abrasive particles of any one of claims 1 to 3, wherein each of the hydrophobic moieties independently comprises at least one selected from the group consisting of an alkyl group having fewer than 20 C atoms, fewer than 10 C atoms, or fewer than 4 C atoms; and an aryl group having fewer than 20 C atoms, fewer than 10 C atoms, or fewer than 8 C atoms.

5. 5. The colloidally stable amphiphilic abrasive particle of claim 1, wherein each of the hydrophobic moieties independently comprises at least one selected from the group consisting of methyl, ethyl, propyl, butyl, phenyl, benzyl, tolyl, and xylyl groups.

6. 6. The colloidally stable amphiphilic abrasive particles of any one of claims 1 to 5, wherein two or more hydrophilic moieties and / or two or more hydrophobic moieties can be attached to a linking atom selected from the group consisting of Si atoms, Ce atoms, Al atoms, Zr atoms, C atoms, P atoms, and N atoms, the linking atom linking or bonding the hydrophilic moieties and / or hydrophobic moieties to the surface of each colloidally stable amphiphilic abrasive particle via a covalent bond.

7. 7. The colloidally stable amphiphilic abrasive particle of claim 1, wherein the hydrophilic moiety is a silane having an amino group, the hydrophobic moiety is a trimethylsilane group, and the colloidally stable amphiphilic abrasive particle has a surface that is highly non-polar and inert with respect to silicon oxide.

8. 8. The colloidally stable amphiphilic abrasive particles of any one of claims 1 to 7, wherein the ratio of the hydrophilic portion to the hydrophobic portion is in the range of 1.00:0.01 to 1.00:10.00, 1.00:0.25 to 1.00:5.00, 1.00:0.30 to 1.00:3.00, 1.00:0.40 to 1.00:2.50, or 1.00:0.50 to 1.00:2.

00.

9. 9. The colloidally stable amphiphilic abrasive particle of any one of claims 1 to 8, wherein the surface of each colloidally stable amphiphilic abrasive particle is a covalently bonded polymeric crosslinked shell.

10. 10. The colloidally stable amphiphilic abrasive particle of any one of claims 1 to 9, wherein the surface of each colloidally stable amphiphilic abrasive particle is a covalently bonded polyorganosiloxane crosslinked shell.

11. 1. A method for making colloidally stable amphiphilic abrasive particles, comprising: a. providing base abrasive particles having reactive M-OH groups on their surfaces, the base abrasive particles being dispersed in a solvent; b. modifying the surface of the base abrasive particle with a first-step surface modifier having at least one hydrophilic group and at least one first reactive group capable of forming a covalent bond with the reactive M-OH group to obtain a one-step modified abrasive particle; c) modifying the surface of the one-step modified abrasive particle with a second-step surface modifier having at least one hydrophobic group and at least one second reactive group capable of forming a covalent bond with a reactive X—OH group on the surface of the one-step modified abrasive particle to obtain the amphiphilic abrasive particle; During the ceremony, said M in said reactive M-OH group is selected from the group consisting of Si, Ce, Al, Zr, hybrids and / or mixtures thereof; said X in said reactive X—OH group is selected from the group consisting of Si, Ce, Al, Zr, C, P, N, hybrids and / or mixtures thereof; A method for making colloidally stable amphiphilic abrasive particles, wherein the solvent is selected from the group consisting of water, alcohol, preferably ethanol, ketone, ester, ether, glycol, and combinations thereof, preferably a combination of water and alcohol.

12. 12. The method of making colloidally stable amphiphilic abrasive particles of claim 11, wherein the at least one first reactive group or the at least one second reactive group is independently selected from the group consisting of si-alkoxide, si-halide (preferably chloride), oximate, acetate, si-hydroxide, and combinations thereof, preferably silicon methoxide and silicon ethoxide.

13. 13. The method of making colloidally stable amphiphilic abrasive particles of claim 11 or 12, wherein the first-step surface modifier is selected from silanes having at least one hydrophilic group, and the second-step surface modifier is selected from silanes having at least one hydrophobic group.

14. 14. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 to 13, wherein the at least one hydrophilic group comprises an N-containing group selected from the group comprising amines and substituted amines, amino groups, ammonium, alkylammonium groups including alkyls with fewer than 20 C atoms, fewer than 10 C atoms, or fewer than 4 C atoms, ammonium groups and substituted ammonium groups, at least one selected from the group comprising sulfonium, phosphonium, sulfate, sulfonate, phosphate, hydroxy, epoxy, carboxy, ether, polyether, or polyether groups, preferably an N-containing group selected from the group comprising amines, amino groups, ammonium, and alkylammonium groups.

15. 15. The method for making colloidally stable amphiphilic abrasive particles according to any one of claims 11 to 14, wherein the at least one hydrophilic group comprises at least one selected from the group consisting of amine, ammonium, and alkylammonium groups, including alkyls having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms.

16. 16. The method for making colloidally stable amphiphilic abrasive particles according to any one of claims 11 to 15, wherein the at least one hydrophobic group comprises at least one selected from the group consisting of an alkyl group having fewer than 20 C atoms, fewer than 10 C atoms, or fewer than 4 C atoms; and an aryl group having fewer than 20 C atoms, fewer than 10 C atoms, or fewer than 8 C atoms.

17. 17. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 16, wherein the at least one hydrophobic group comprises at least one selected from the group consisting of methyl, ethyl, propyl, butyl, phenyl, benzyl, tolyl, and xylyl.

18. 18. The method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 to 17, wherein the second-step surface modifier comprises a silane having at least two, preferably at least three, hydrophobic groups comprising alkyl having less than 20 C atoms, less than 10 C atoms, or less than 4 C atoms, or aryl having less than 20 C atoms, less than 10 C atoms, or less than 8 C atoms.

19. 19. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 18, wherein the second-step surface modifier does not carry a functional group on the hydrophobic group that is an alkyl or aryl group.

20. 20. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 19, wherein the solvent is selected from the group consisting of water, ethanol, acetone, diethyl ether, propylene glycol dimethyl ether, propylene glycol monoacetyl ester, isopropanol, n-propanol, propylene glycol monomethyl ether, and combinations thereof, preferably a combination of water and ethanol.

21. 21. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 20, wherein the total amount of the first-step surface modifier and the second-step surface modifier is in the range of 0.01 to 1.0 mmol / g (mass of abrasive calculated as dry matter), 0.025 to 0.8 mmol / g, 0.05 to 0.5 mmol / g, or 0.1 to 0.4 mmol / g.

22. 22. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 21, wherein the base abrasive particles are selected from the group consisting of colloidal silica, fumed silica, alumina, ceria, and combinations thereof.

23. 23. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 22, wherein the first-step surface modifier is selected from the group consisting of amino-polyether silanes and betaine-type silanes.

24. 24. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 23, wherein the first-step surface modifier is selected from the group consisting of 3-aminopropyl derivatives of ethoxysilane or methoxysilane, and combinations thereof.

25. 25. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 24, wherein the first step surface modifier is 3-aminopropylmethyldimethoxysilane.

26. 26. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 25, wherein the first-step surface modifiers are capable of reacting among themselves to form a covalently bonded polymeric crosslinked shell around the base abrasive particle.

27. 27. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 26, wherein the second-step surface modifier is selected from the group consisting of trimethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, diphenylsilanediol, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, dimethylethylmethoxysilane, dimethyloctylmethoxysilane, dimethyloctadecylchlorosilane, dimethylhexadecylmethoxysilane, dimethyl(methylphenyl)methoxysilane, potassium trimethylsilanoate, triethylmethoxysilane, and combinations thereof.

28. 28. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 27, wherein the second-step surface modifier is selected from the group consisting of trimethylmethoxysilane, trimethylethoxysilane, and combinations thereof.

29. 29. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 28, wherein the first-step surface modifier is 3-aminopropylmethyldimethoxysilane and the second-step surface modifier is selected from the group consisting of trimethylmethoxysilane, trimethylethoxysilane, and combinations thereof.

30. 30. A method of making colloidally stable amphiphilic abrasive particles according to any one of claims 11 to 29, wherein the ratio of modifier to reactant in the first step is in the range of 9.9:1 to 0.1:9.9, preferably 9:1 to 1:

9.

31. 31. The method of making colloidally stable amphiphilic abrasive particles of any one of claims 11 to 30, wherein the first-step surface modifier may be used in combination with a reactant selected from the group consisting of tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and combinations thereof, and the ratio of the first-step modifier to the reactant ranges from 9.9:1 to 0.1:9.9, preferably from 9:1 to 1:

9.

32. 32. A method for making colloidally stable amphiphilic abrasive particles according to any one of claims 11 to 31, further comprising, after step c, step d, retaining water as the only dispersing liquid after the surface modification of the second step.

33. Colloidally stable amphiphilic abrasive particles made according to any one of claims 11 to 32.

34. 1. A chemical mechanical polishing (CMP) composition comprising: Colloidally stable amphiphilic abrasive particles according to any one of claims 1 to 10 or claim 33; a solvent, Optionally, Organic and inorganic salts as colloid stabilizers, a catalyst, including but not limited to fluoride ions, metal salts, or metal alkoxides such as titanium isopropoxide; acid / base pH buffers, biocides, oxidizing agents, catalyst, and a corrosion inhibitor; the solvent is selected from the group consisting of water-soluble solvents selected from the group consisting of water, alcohols, ethers, and ketones, and combinations thereof; The CMP composition has a pH of 2-10, 2-8, 2-6, 2-5, 2-4, or 2-3.

35. 1. A chemical mechanical polishing (CMP) method comprising: providing a substrate having at least one surface comprising tungsten; 1. A chemical mechanical polishing (CMP) composition comprising: Colloidally stable amphiphilic abrasive particles according to any one of claims 1 to 10 or claim 33; an aqueous solvent; providing a chemical-mechanical polishing (CMP) composition having a pH of 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3; contacting the surface of the semiconductor substrate with a polishing pad and the chemical-mechanical polishing composition; and polishing said at least one surface comprising tungsten.

36. The surface of the semiconductor substrate further comprises a silicon dioxide film, W:SiO ２ 36. The chemical mechanical polishing (CMP) method of claim 35, wherein the removal selectivity is greater than 80, 100, 150, or 200.

37. 1. A chemical mechanical polishing (CMP) system comprising: Polishing pads, a substrate having at least one surface comprising tungsten; 1. A chemical mechanical polishing (CMP) composition comprising: Colloidally stable amphiphilic abrasive particles according to any one of claims 1 to 10 or claim 33, and Contains a water-soluble solvent, a chemical-mechanical polishing (CMP) composition having a pH of 2 to 10, 2 to 8, 2 to 6, 2 to 5, 2 to 4, or 2 to 3; A chemical-mechanical polishing (CMP) system in which the surface of the semiconductor substrate is subjected to the polishing pad and the chemical-mechanical polishing composition so that the tungsten can be polished.

38. The surface of the semiconductor substrate further comprises a silicon dioxide film, W:SiO ２ 38. The chemical mechanical polishing (CMP) system of claim 37, wherein the removal selectivity is greater than 80, 100, 150, or 200.

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