Quaternary ammonium-based surface-modified silica, compositions thereof, methods of making, and methods of use

Abstract

To provide silica particles with a high zeta potential and a minimal change in particle size.SOLUTION: The present invention provides a surface modified silica comprising silica and a quaternary ammonium-based polymer, and as another object, a method for polishing a substrate using the surface modified silica comprising silica and a quaternary ammonium-based polymer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a surface-modified silica, wherein the silica is modified with a quaternary ammonium polymer. Further, a polishing composition containing the surface-modified silica, and a method for making and using the surface-modified silica are provided. [Background technology]

[0002] Chemical-mechanical polishing (CMP) is a process of removing material from the surface of a substrate (such as a semiconductor wafer), and the surface is polished (planarized) by combining a physical process, such as abrasion, with a chemical process, such as oxidation or chelation. In its most basic form, CMP involves applying a slurry to the substrate surface or to a polishing pad that polishes the substrate. This process achieves both the removal of unwanted material and the planarization of the substrate surface. The removal or polishing process is not desirably purely physical or purely chemical, but rather involves a synergistic combination of both.

[0003] The polishing composition used in the CMP process can be characterized according to its polishing rate (i.e., removal rate) and its planarization efficiency. The polishing rate refers to the rate at which material is removed from the substrate surface and is usually expressed in units of length (thickness) per unit time (e.g., angstroms per minute). Planarization efficiency relates to the reduction in step height relative to the amount of material removed from the substrate. Specifically, the polishing surface must first contact the "high point" of the surface and then remove material to form a flat surface. A process that results in achieving a flat surface with less material removal is considered more efficient than a process that requires more material removal to achieve planarity. Furthermore, surface scratches that can be caused by CMP are a very harmful defect in semiconductor manufacturing. Therefore, the development of a polishing composition is very important to achieve adequate CMP performance at a sufficient polishing rate without causing the above problems.

[0004] These polishing compositions contain several components, including abrasive grains. The type of abrasive grain has a significant impact on the CMP process, including the overall polishing rate and planarization efficiency. Common abrasive grains include silicon dioxide, cerium oxide, aluminum oxide, zirconium oxide, and tin oxide.

[0005] These and other challenges are addressed by the subject matter disclosed herein. Summary of the Invention [Problem to be solved by the invention]

[0006] As embodied and broadly described herein, in accordance with the objectives of the subject matter disclosed herein or the problems to be solved by the present invention, it is an object of the present invention to provide a surface-modified silica comprising silica and a quaternary ammonium-based polymer. Another object of the present invention is to provide a method for polishing a substrate using a surface-modified silica comprising silica and a quaternary ammonium-based polymer. [Means for solving the problem]

[0007] Thus, in one aspect, the presently disclosed subject matter is a surface-modified silica comprising silica and a quaternary ammonium-based polymer, wherein the quaternary ammonium-based polymer has the formula (I):

[0008] [ka]

[0009] [In the formula, R 1 is selected from substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted aryl, substituted heteroaryl, and substituted cycloalkyl; R 2 is selected from substituted or unsubstituted C1-C8 alkyl, substituted or unsubstituted aryl, substituted heteroaryl, and substituted cycloalkyl; R 3is a substituted or unsubstituted alkyl ether, R 4 is in each case a substituted or unsubstituted C1-C8 alkyl; X is in each case a counterion, m is an integer between 1 and 20,000; n is an integer between 1 and 10,000. The present invention relates to a surface-modified silica represented by the compound:

[0010] In another aspect, the subject matter described herein is directed to a polishing composition, the polishing composition comprising a surface-modified silica comprising silica and a quaternary ammonium-based polymer, and a dispersing medium.

[0011] In another aspect, the subject matter described herein is directed to a method for polishing a substrate, the method comprising the steps of: a) providing a polishing composition of an aspect of the present invention; and b) polishing the substrate with the polishing composition to provide a polished substrate.

[0012] In yet another aspect, the subject matter described herein is directed to a method for preparing a surface-modified silica, the method comprising the steps of: a) preparing a dispersion comprising silica and a dispersion medium; and b) adding a quaternary ammonium-based polymer to the dispersion, thereby preparing the surface-modified silica.

[0013] These and other aspects are disclosed in further detail below. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention may be understood more readily by reference to the following detailed description of the invention and the examples included therein.

[0015] Before the present compounds, compositions, and / or methods are disclosed and described, it is to be understood that they are not limited to particular synthetic methods, unless otherwise specified, or to particular components, unless otherwise specified, which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and materials are now described.

[0016] In this specification, the term "X to Y" indicates a range and means "X or more and Y or less." When multiple "X to Y" values ​​are used, such as "X1 to Y1" or "X2 to Y2," the disclosure of each upper limit, the disclosure of each lower limit, and combinations of these upper and lower limits are all considered to be legitimate (i.e., legitimate grounds for amendment). Specifically, amendments to X1 or more, amendments to Y2 or less, amendments to X1 or less, amendments to Y2 or more, amendments between X1 and X2, and amendments between X1 and Y2 must all be deemed legitimate. Unless otherwise specified, all operations and measurements of physical properties are performed at room temperature (20-25°C) and a relative humidity of 40-50% RH. The concentrations described herein may be concentrations at the point of use (POU) or before dilution to the POU concentration.

[0017] As described herein, an embodiment is a surface-modified silica, where the silica is modified by a quaternary ammonium-based polymer.Furthermore, a polishing composition comprising the surface-modified silica, and a method for making and using the surface-modified silica are provided.The surface-modified silica is intended for use in a polishing composition, and the polishing composition can be used to polish a substrate.The surface-modified silica and its preparation method exhibit at least one of the following advantages: 1) high positive surface charge over a wide pH range; 2) cationization of silica with only slight change in particle size.

[0018] Zeta potential, mean particle size, and polydispersity index are important properties of surface-modified silica.

[0019] The surface modified silicas described herein have uses such as, but not limited to, incorporation into CMP slurries for chemical mechanical polishing of semiconductor wafers.

[0020] A.Definition Set forth below are definitions of various terms used to describe this invention. These definitions apply to the terms as they are used throughout this specification, unless otherwise limited in specific instances, either individually or as part of a larger group.

[0021] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "particle" or an "alkyl group" includes a mixture of two or more such particles or alkyl groups.

[0022] Ranges can be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of "about" immediately preceding it, it will be understood that the particular value forms another embodiment. Further, the endpoints of each range are understood to be significant both in relation to the other endpoint, and independently of the other endpoint. Also, there are a number of values ​​disclosed herein, and each value is understood to be disclosed herein as "about" that particular value in addition to the value itself. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Also, it is understood that each unit between two particular units is disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0023] References in the specification and concluding claims to parts by weight of a particular element or component in a composition indicate the weight relationship between that element or component and any other element or component in the composition or article for which the parts by weight are expressed. Thus, in a compound containing 2 parts by weight of component X and 5 parts by weight of component Y, X and Y are present in a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the composition.

[0024] Weight percent (wt %) of a component is based on the total weight of the vehicle or composition in which the component is contained, unless specifically stated to the contrary.

[0025] As used herein, the terms "optional" and "optionally" mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not occur.

[0026] As used herein, the term "alkyl" refers to a straight or branched chain hydrocarbon containing 1 to 20 carbon atoms. Representative examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl, n-decyl, and the like. Further examples are designated by their carbon chain length, such as C2, C4, C6, C8, C10, C12, C14, C16, C18, and C20. These groups may be substituted with a group selected from halo (e.g., haloalkyl), haloalkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heterocyclo, heterocycloalkyl, hydroxyl, alkoxy (thereby generating polyalkoxy such as polyethylene glycol), alkenyloxy, alkynyloxy, haloalkoxy, cycloalkoxy, cycloalkylalkyloxy, aryloxy, arylalkyloxy, heterocyclooxy, heterocycloalkyloxy, mercapto, carboxy, alkylamino, alkenylamino, alkynylamino, haloalkylamino, cycloalkylamino, cycloalkylalkylamino, arylamino, arylalkylamino, heterocycloamino, heterocycloalkylamino, disubstituted amino, ester, amido, nitro, or cyano.

[0027] The term "alkylene" refers to a divalent group formed by removing one hydrogen atom from an "alkyl." Representative examples of alkylene include the divalent forms of representative alkyls.

[0028] The term "cycloalkyl" refers to a hydrocarbon 3- to 8-membered monocyclic or 7- to 14-membered bicyclic ring system having at least one saturated ring or at least one non-aromatic ring, where the non-aromatic ring may have some degree of unsaturation. A cycloalkyl group can be optionally substituted with one or more substituents. In one embodiment, 0, 1, 2, 3, or 4 atoms of each ring of a cycloalkyl group can be substituted with a substituent. Representative examples of cycloalkyl groups include cyclopropyl, cyclopentyl, cyclohexyl, cyclobutyl, cycloheptyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl, and the like.

[0029] The term "cycloalkylene" refers to a divalent group formed by removing one hydrogen atom from a "cycloalkyl." A cycloalkylene group can be optionally substituted with one or more substituents. In one embodiment, 0, 1, 2, 3, or 4 atoms of each ring of a cycloalkylene group can be substituted with a substituent. Representative examples of cycloalkylene groups include divalent versions of representative examples of cycloalkyl groups.

[0030] As used herein, the term "heteroaryl" or "heteroaromatic" refers to a monovalent aromatic radical of a five- or six-membered ring, including fused ring systems of 5 to 20 atoms containing one or more heteroatoms independently selected from nitrogen, oxygen, and sulfur, at least one of which is aromatic. Examples of heteroaryl groups include pyridinyl (including, for example, 2-hydroxypyridinyl), imidazolyl, imidazopyridinyl, pyrimidinyl (including, for example, 4-hydroxypyrimidinyl), pyrazolyl, triazolyl (including, for example, 3-amino-1,2,4-triazole or 3-mercapto-1,2,4-triazole), pyrazinyl (including, for example, aminopyrazine), tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, and the like. Heteroaryl groups include pyrrolyl, quinolinyl, isoquinolinyl, tetrahydroisoquinolinyl, indolyl, benzimidazolyl, benzofuranyl, cinnolinyl, indazolyl, indolizinyl, phthalazinyl, pyridazinyl, triazinyl, isoindolyl, pteridinyl, purinyl, oxadiazolyl, triazolyl, thiadiazolyl, furazanyl, benzofurazanyl, benzothiophenyl, benzothiazolyl, benzoxazolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, and furopyridinyl. Thus, in some embodiments, heteroaryl groups are monocyclic or bicyclic. Heteroaryl groups are optionally independently substituted with one or more substituents described herein.

[0031] The term "heteroarylene" refers to a divalent group formed by removing a hydrogen atom from a "heteroaryl." Examples of heteroarylene groups include the divalent versions of heteroaryl groups. Heteroarylene groups, in some embodiments, are monocyclic or bicyclic. Heteroarylene groups are optionally substituted independently with one or more substituents described herein.

[0032] As used herein, the term "aryl" refers to a hydrocarbon monocyclic, bicyclic, or tricyclic aromatic ring system. An aryl group can be optionally substituted with one or more substituents. In one embodiment, 0, 1, 2, 3, 4, 5, or 6 atoms of each ring of an aryl group can be substituted with a substituent. Examples of aryl groups include phenyl, naphthyl, anthracenyl, fluorenyl, indenyl, azulenyl, and the like.

[0033] The term "arylene" refers to a divalent group of a hydrocarbon monocyclic, bicyclic, or tricyclic aromatic ring system. An arylene group can be optionally substituted with one or more substituents. In one embodiment, 0, 1, 2, 3, 4, 5, or 6 atoms of each ring of an arylene group can be substituted with a substituent. Examples of arylene groups include divalent versions of the aryl groups.

[0034] As used herein, the term "substituted" refers to a moiety (such as an alkyl group) that is attached to one or more additional organic radicals. In some embodiments, the substituted moiety contains 1, 2, 3, 4, or 5 additional substituents or radicals. Suitable organic substituent radicals include, but are not limited to, hydroxyl, amino, monosubstituted amino, disubstituted amino, mercapto, alkylthiol, alkoxy, substituted alkoxy, or haloalkoxy radicals, as these terms are defined herein. Unless otherwise specified herein, an organic substituent can contain 1 to 4 or 5 to 8 carbon atoms. When a substituted moiety is attached to more than one substituent radical, the substituent radicals can be the same or different.

[0035] As used herein, the term "alkoxy" used alone or as part of another group refers to the radical --OR, where R is an alkyl group as defined herein.

[0036] As used herein, the term "halo" refers to any suitable halogen, including -F, -Cl, -Br, and -I.

[0037] As used herein, the term "mercapto" refers to a -SH group.

[0038] As used herein, the term "cyano" refers to the group --CN.

[0039] As used herein, the term "carboxylic acid" refers to the group --C(O)OH.

[0040] As used herein, the term "hydroxyl" refers to an --OH group.

[0041] As used herein, the term "nitro" refers to the group --NO.sub.2.

[0042] As used herein, the terms “ether” and “alkyl ether” refer to a group of alkyl groups of formula R a -OR b where R a and R b may independently be an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group, as described herein. As used herein, the term "polyether" refers to a group of groups of the formula -(R a -OR b ) x wherein R a and R b can independently be an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group, as described herein, and "x" is an integer from 1 to 500. Examples of polyether groups include polyethylene oxide, polypropylene oxide, and polybutylene oxide.

[0043] As used herein, the term "oxyalkylene" means -OR-, where R is alkylene, as defined herein.

[0044] As used herein, the term "acyl," used alone or as part of another group, refers to the radical --C(O)R, where R is any suitable substituent, such as aryl, alkyl, alkenyl, alkynyl, cycloalkyl, or other suitable substituent, as described herein.

[0045] As used herein, the term "alkylthio," used alone or as part of another group, refers to an alkyl group, as defined herein, appended to the parent molecular moiety through a thiol moiety, as defined herein. Representative examples of alkylthio include, but are not limited to, methylthio, ethylthio, tert-butylthio, hexylthio, and the like.

[0046] As used herein, the term "amino" refers to the -NH2 radical.

[0047] As used herein, the term "alkylamino" or "monosubstituted amino" used alone or as part of another group refers to the -NHR radical, where R is an alkyl group, as defined herein.

[0048] As used herein, the term "disubstituted amino" used alone or as part of another group refers to -NR a R b means a radical, wherein R a and R b are independently selected from alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heterocyclo, and heterocycloalkyl groups, as defined herein.

[0049] As used herein, the term "ester," used alone or as part of another group, refers to the -C(O)OR radical, where R is any suitable substituent, such as alkyl, cycloalkyl, alkenyl, alkynyl, or aryl, as defined herein.

[0050] As used herein, the term "amide" used alone or as part of another group means -C(O)NR a R b refers to a radical, where R a and R b is any suitable substituent such as alkyl, cycloalkyl, alkenyl, alkynyl, or aryl.

[0051] As used herein, the term "unsubstituted" refers to a moiety (such as an alkyl group) that is not bonded to one or more additional organic or inorganic substituent radicals as defined above, i.e., such a moiety is substituted only with hydrogen.

[0052] As used herein, the term "monocyclic" refers to a molecular structure that contains a single ring of atoms, such as, for example, benzene or cyclopropane.

[0053] As used herein, the term "bicyclic" refers to a molecular structure that contains two rings of atoms fused together, such as, for example, naphthalene.

[0054] As used herein, the term "counterion" refers to an ion that has a charge opposite to that of the substance with which it is associated. A counterion can be any organic or inorganic moiety that stabilizes the charge of the parent compound. Counterions can have a positive or negative charge. Non-limiting examples of counterions include halide ions (e.g., F - , Cl - , Br - , I - ), NO3 - , ClO4 - , O.H. - , H2PO4- , HCO3 - , HSO4 - , sulfonate ions (e.g., methanesulfonate ion, trifluoromethanesulfonate ion, p-toluenesulfonate ion, benzenesulfonate ion, 10-camphorsulfonate ion, naphthalene-2-sulfonate ion, naphthalene-1-sulfonic acid-5-sulfonate ion, ethane-1-sulfonic acid-2-sulfonate ion, etc.), carboxylate ions (e.g., acetate ion, propanoate ion, benzoate ion, glycerate ion, lactate ion, tartrate ion, glycolate ion, gluconate ion, etc.), BF4 - , PF4 - , PF6 - , AsF6 - , and SbF6 - Non-limiting examples of counterions that may be multivalent include CO3 2- , HPO4 2- , PO4 3- , B4O7 2- , SO4 2- , S2O3 2- , carboxylate anions (e.g., tartrate, citrate, fumarate, maleate, malate, malonate, gluconate, succinate, glutarate, adipate, pimelate, suberate, azelaate, sebacate, salicylate, phthalate, aspartate, glutamate, etc.), and carboranes.

[0055] The positive counterion can be monovalent (e.g., alkali metal or ammonium), divalent (e.g., earth alkali metal), or trivalent (e.g., aluminum). Non-limiting examples of positive counterions are Li + , Na + , or K + and other alkali metal cations.

[0056] B. Surface-modified silica The present disclosure relates to surface-modified silica, in which the silica surface is modified with a quaternary ammonium polymer. By modifying the silica surface in this manner, silica particles can be produced that have a high zeta potential and minimal change in particle size.

[0057] The basic mechanism of chemical mechanical polishing (CMP) is to soften a surface layer through a chemical reaction, and then remove the softened layer through mechanical force using abrasive particles. However, the role of CMP is not limited to material removal; it also includes planarization, surface smoothing, uniformity control, and defect reduction. Therefore, improving semiconductor yields is affected by CMP processing. Surface scratches that can be caused by CMP are very harmful defects in semiconductor manufacturing. Therefore, the development of polishing compositions is very important to achieve appropriate CMP performance without surface scratches. Requirements for CMP may include a planarized surface with a flatness of less than 15 nm, a roughness-free surface with a surface roughness of less than 1 nm, and a defect-free surface with zero scratches and pits per wafer. It is desirable to achieve planarization without contamination, with high productivity, and with a high removal rate of the desired material to be removed.

[0058] The surface-modified silica and its preparation method exhibit at least one of the following advantages: 1) high positive surface charge over a wide pH range; 2) cationization of the silica with only small changes in particle size.

[0059] 1. Quaternary ammonium polymers In one aspect, the presently disclosed subject matter is a surface-modified silica comprising silica and a quaternary ammonium-based polymer, wherein the quaternary ammonium-based polymer has the formula (I):

[0060] [ka]

[0061] [In the formula, R 1is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted or unsubstituted heteroarylene, and substituted or unsubstituted cycloalkylene; R 2 is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted or unsubstituted heteroarylene, and substituted or unsubstituted cycloalkylene; R 3 is a substituted or unsubstituted C1-C8 alkylene or a substituted or unsubstituted oxyalkylene, R 4 are each independently a substituted or unsubstituted C1-C8 alkyl; X is in each case a counterion, m is an integer between 1 and 20,000; n is an integer between 1 and 10,000. The present invention relates to a surface-modified silica represented by the compound:

[0062] In some embodiments, R 1 is an unsubstituted C1-C8 alkylene. In some embodiments, R 1 is an unsubstituted C1-C4 alkylene. In some embodiments, R 1 is an unsubstituted C1-C3 alkylene. In some embodiments, R 1 is -CH- or -CHCH-. In some embodiments, R 1 is -CH2CH2-.

[0063] In some embodiments, R 2 is an unsubstituted C1-C8 alkylene. In some embodiments, R 2 is an unsubstituted C1-C4 alkylene. In some embodiments, R 2 is an unsubstituted C1-C3 alkylene. In some embodiments, R 2 is -CH- or -CHCH-. In some embodiments, R 2 is -CH2CH2-.

[0064] In some embodiments, R 3 is methylene, ethylene, propylene, butylene, isopropylene, or isobutylene. In some embodiments, R 4 is methyl.

[0065] In some embodiments, R 3 is unsubstituted oxyalkylene. In some embodiments, R 3 is —O—(C1-C8 alkylene)-. In some embodiments, R 3 is —O—(C1-C4 alkylene)-. In some embodiments, R 3 is —O—(C alkylene)-. In some embodiments, R 3 is —O—(C1 or C2 alkylene)-. In some embodiments, R 3 is -OCH2CH2-. In another embodiment, R 3 is the formula -(R a -OR b ) x -, wherein R a and R b can independently be a C1-C8 alkylene or arylene, and "x" is an integer from 1 to 500. In some embodiments, R a and R b are -CH2-, respectively.

[0066] In some embodiments, R 4 are each independently unsubstituted C1-C4 alkyl. In some embodiments, R 4 are each independently methyl, ethyl, propyl, butyl, isopropyl, or isobutyl. In some embodiments, R 4 is methyl.

[0067] Without being bound by theory, if the number of C is large, the hydrophobicity of the cationic polymer increases, making the abrasive grains more likely to aggregate. In addition, there is a risk that steric hindrance will occur between the N atoms that access the silica abrasive grain surface, hindering adsorption itself. Therefore, 1 ~R 4 The number of C's should be small. Therefore, R 4 is preferably methyl or ethyl.

[0068] In some embodiments, R 1 and R 2 is -CH2CH2- and R 3 is -OCH2CH2- and R 4 is methyl. Thus, in some embodiments, the quaternary ammonium-based polymer has the formula (II):

[0069] [ka]

[0070] wherein X, n, and m are as defined above. In a further embodiment, X is Cl - or OH - is.

[0071] In some embodiments, in the compound of Formula (II), X is Cl - where n and m are integers sufficient to provide an overall molecular weight of about 5,000 g / mol. As further described herein, this compound is also referred to as POEDMIED2C. This compound is also known as poly[oxyethylene(dimethyliminio)ethylene-(dimethyliminio)ethylene dichloride], polyquaternium WSCP, or EBC1.

[0072] In some embodiments, n is an integer selected from 1 to 10,000, e.g., 1 to 5,000, 1 to 1,000, 1 to 500, 1 to 250, 1 to 100, or 1 to 50. In some embodiments, n is in the range of 50 to 150, 25 to 300, or 10 to 500.

[0073] In some embodiments, m is an integer selected from 1 to 20,000, e.g., 1 to 10,000, 1 to 5,000, 1 to 1,000, 1 to 500, 1 to 250, 1 to 100, 1 to 50, 2 to 40, 3 to 30, or 4 to 20. In some embodiments, m is in the range of 50 to 150, 25 to 300, or 10 to 500. In some embodiments, m is an integer selected from 2 to 10,000, 2 to 2,000, 2 to 1,000, 2 to 500, 2 to 100, 4 to 80, 6 to 60, 8 to 40, or 4 to 20.

[0074] In some embodiments, n and m are related such that m=2n.

[0075] In some embodiments, the average molecular weight of the quaternary ammonium-based polymer is in the range of about 500 g / mol to about 200,000 g / mol, about 1,000 g / mol to about 50,000 g / mol, about 1,500 g / mol to about 25,000 g / mol, about 2,000 g / mol to about 15,000 g / mol, about 2,500 g / mol to about 10,000 g / mol, about 3,000 g / mol to about 8,000 g / mol, 3,500 g / mol to about 7,000 g / mol, or 4,000 g / mol to about 5,000 g / mol. In some embodiments, the average molecular weight of the quaternary ammonium-based polymer is less than about 100,000 g / mol, less than about 50,000 g / mol, less than about 25,000 g / mol, or less than about 10,000 g / mol. In some embodiments, the average molecular weight of the quaternary ammonium-based polymer is about 2,500 g / mol, about 5,000 g / mol, about 10,000 g / mol, about 25,000 g / mol, about 50,000 g / mol, or about 100,000 g / mol. In some embodiments, the average molecular weight may be measured by gel permeation chromatography (GPC) using polystyrene standards of known molecular weight. In some embodiments, the average molecular weight may be a weight average molecular weight.

[0076] In some embodiments, X is a negatively charged counterion known in the art. For example, X in each case is a halide ion (e.g., F - , Cl - , Br - , I - ), NO3 - , ClO4 - , O.H. - , H2PO4 - , HCO3 - , HSO4 -, sulfonate ions (e.g., methanesulfonate ion, trifluoromethanesulfonate ion, p-toluenesulfonate ion, benzenesulfonate ion, 10-camphorsulfonate ion, naphthalene-2-sulfonate ion, naphthalene-1-sulfonic acid-5-sulfonate ion, ethane-1-sulfonic acid-2-sulfonate ion, etc.), carboxylate ions (e.g., acetate ion, propanoate ion, benzoate ion, glycerate ion, lactate ion, tartrate ion, glycolate ion, gluconate ion, etc.), BF4 - , PF4 - , PF6 - , AsF6 - , and SbF6 - Non-limiting examples of counter ions that may be multivalent include CO3 2- , HPO4 2- , PO4 3- , B4O7 2- , SO4 2- , S2O3 2- , carboxylate anions (e.g., tartrate, citrate, fumarate, maleate, malate, malonate, gluconate, succinate, glutarate, adipate, pimelate, suberate, azelaate, sebacate, salicylate, phthalate, aspartate, glutamate, etc.), and carboranes. In some embodiments, X in each instance is independently selected from the group consisting of hydroxide, halide, nitrate, carbonate, sulfate, phosphate, and acetate. In some embodiments, X is hydroxide or halide.

[0077] As in any embodiment above, a surface-modified silica is provided, wherein the quaternary ammonium-based polymer has a molecular weight between about 2,000 g / mol and about 15,000 g / mol.

[0078] 2. Silica (silica particles) The surface-modified silica includes silica. In one embodiment, the silica may be colloidal silica. Examples of methods for producing colloidal silica include the soda silicate method and the sol-gel method, both of which are known in the art. Colloidal silica produced by either of these methods can be suitably used as the silica in the present invention. However, from the viewpoint of reducing metal impurities, colloidal silica produced by the sol-gel method, which enables the production of high-purity colloidal silica, is preferred. In some embodiments, the silica (silica particles) may be in the form of an aqueous dispersion.

[0079] 3. Methods for preparing surface-modified silica The present disclosure relates to surface-modified silica, in which the silica surface is modified with a quaternary ammonium polymer. By modifying the silica surface in this manner, silica particles can be produced that have a high zeta potential and minimal change in particle size.

[0080] Furthermore, the preparation of the surface-modified silica described herein has advantages over conventional methods for producing surface-modified abrasive grains (e.g., as disclosed in JP 2012-040671 A). These advantages include, for example, fewer steps in the preparation of the surface-modified silica, in that the present invention completes the modification by simply mixing the quaternary ammonium polymer.

[0081] In some embodiments, the surface-modified silica may be in the form of an aqueous dispersion.

[0082] The surface-modified silica can be produced quickly and economically, and the particle size of the surface-modified silica does not change significantly from the particle size of the unmodified silica.

[0083] The surface-modified silica may have an average secondary particle size of about 10 nm or more, about 25 nm or more, about 50 nm or more, about 60 nm or more, or about 70 nm or more. Alternatively, or in addition, the abrasive grains may have an average secondary particle size of about 500 nm or less, about 200 nm or less, about 150 nm or less, about 100 nm or less, about 90 nm or less, about 80 nm or less, about 70 nm or less, or about 60 nm or less. For example, in embodiments, the abrasive grains may have an average secondary particle size ranging from about 10 nm to about 500 nm, from about 25 nm to about 250 nm, from about 50 nm to about 100 nm, or from about 60 nm to about 80 nm. In some embodiments, the average secondary particle size is about 50 nm, about 60 nm, about 70 nm, about 80 nm, or about 90 nm.

[0084] Preferred embodiments of the secondary particle diameter range include a range of about 50 nm to about 100 nm, or about 60 nm to about 80 nm. A more preferred range is about 60 nm to about 80 nm. When the average secondary particle diameter is within this preferred range, surface defects such as scratches on the substrate surface can be suppressed.

[0085] The average secondary particle size of the surface-modified silica can be measured by dynamic light scattering (DLS). As used herein, the average secondary particle size is also referred to as the "z-average size."

[0086] In particle size distribution analysis by dynamic light scattering, the polydispersity index (PDI) is another widely used measurement. Generally speaking, the higher the PDI value, the wider the particle size distribution. Therefore, a lower PDI value is desirable. In some embodiments, the PDI of the surface-modified silica is in the range of about 0 to about 0.20, about 0 to about 0.10, or about 0 to about 0.05. Alternatively, the PDI is in the range of about 0.01 to about 0.20, about 0.025 to about 0.15, or about 0.05 to about 0.10. In some embodiments, the PDI is less than about 0.15, less than about 0.10, less than about 0.75, less than about 0.70, or less than about 0.50. In some embodiments, the polydispersity index (PDI) may be measured using a Malvern Zetasizer. The polydispersity index (PDI) can be automatically calculated by the instrument simultaneously with the particle size.

[0087] Surface-modified silica particles have a permanent positive charge.The charge on such particles is generally referred to in the art as zeta potential (or electrokinetic potential).The zeta potential of a particle refers to the potential difference between the charge of the ions surrounding the particle and the charge of the bulk solution of the polishing composition (for example, the liquid carrier and any other components dissolved therein).

[0088] Thus, the surface-modified silica described herein has an associated zeta potential. In one embodiment, the surface-modified silica has a positive zeta potential. In some embodiments, the surface-modified silica has a positive zeta potential when in a polishing composition. The positive zeta potential can be in the range of about 10 mV to about 90 mV, about 20 mV to about 80 mV, about 30 mV to about 70 mV, or about 40 mV to about 60 mV. In some embodiments, the zeta potential is about 30 mV, about 35 mV, about 40 mV, about 45 mV, about 50 mV, about 55 mV, about 60 mV, about 65 mV, or about 70 mV. In some embodiments, the zeta potential is greater than about 20 mV, greater than about 30 mV, greater than about 40 mV, or greater than about 50 mV. In some embodiments, the zeta potential may be measured using a Malvern Zetasizer.

[0089] The surface-modified silica may have an associated electrical conductivity (EC). The electrical conductivity of the surface-modified silica described herein is greater than 0 to about 1.0 mS / cm. In some embodiments, the electrical conductivity is greater than 0 to about 0.75 mS / cm, greater than 0 to about 0.50 mS / cm, greater than 0 to about 0.25 mS / cm, greater than 0 to about 0.15 mS / cm, greater than 0 to about 0.10 mS / cm, greater than 0 to about 0.05 mS / cm, or greater than 0 to about 0.03 mS / cm. In some embodiments, the electrical conductivity is about 0.01 mS / cm to about 1.0 mS / cm, about 0.02 mS / cm to about 0.50 mS / cm, or about 0.03 mS / cm to about 0.1 mS / cm. In some embodiments, the electrical conductivity is about 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, or 0.15 mS / cm. In some embodiments, the upper limit of the electrical conductivity is about 0.25 mS / cm, about 0.20 mS / cm, about 0.18 mS / cm, about 0.16 mS / cm, about 0.14 mS / cm, about 0.12 mS / cm, about 0.10 mS / cm, about 0.08 mS / cm, about 0.07 mS / cm, about 0.06 mS / cm, about 0.05 mS / cm, about 0.04 mS / cm, or about 0.03 mS / cm. In some embodiments, the electrical conductivity may be a value measured using a Thermofisher Scientific Orion Star A212. The electrical conductivity of the surface-modified silica may be the electrical conductivity of an aqueous dispersion of the surface-modified silica.

[0090] The surface-modified silica particles described herein can be further characterized by the relationship of the quaternary ammonium-based polymer molecules to the silica particles. This relationship is defined herein as (N + / N - ) where a higher number indicates a more complete coating of the silica particles. Thus, in some embodiments, N + / N -The value is about 500 or greater, greater than about 500, greater than about 1,000, greater than about 2,000, greater than about 3,000, greater than about 4,000, greater than about 5,000, greater than about 6,000, or greater than about 7,000. + / N - The value is about 500, about 1,000, about 2,500, about 5,000, or about 7,000.

[0091] As described herein, some embodiments are surface-modified silicas comprising silica and a quaternary ammonium-based polymer, wherein the quaternary ammonium-based polymer is represented by Formula (I):

[0092] [ka]

[0093] [In the formula, R 1 is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted or unsubstituted heteroarylene, and substituted or unsubstituted cycloalkylene; R 2 is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted or unsubstituted heteroarylene, and substituted or unsubstituted cycloalkylene; R 3 is a substituted or unsubstituted oxyalkylene, and R 4 are each independently a substituted or unsubstituted C1-C8 alkyl, X is a counter ion in each case, m is an integer between 1 and 20,000, and n is an integer between 1 and 10,000.

[0094] As in any of the above embodiments, there is provided a surface-modified silica wherein each X is independently selected from the group consisting of hydroxide, halide, nitrate, carbonate, sulfate, phosphate, and acetate.

[0095] As in any embodiment above, R 1 and R 2are each independently substituted or unsubstituted C1-C8 alkylene, and R 4 are each independently a substituted or unsubstituted C1-C8 alkyl. 1 and R 2 are each independently an unsubstituted C1-C4 alkylene or an unsubstituted C1-C3 alkylene, and R 4 are each independently unsubstituted C1-C4 alkyl, unsubstituted C1-C3 alkyl, or unsubstituted C1 or unsubstituted C2 alkyl. 1 and R 2 is -CH2CH2-.

[0096] As in any embodiment above, R 4 is methyl.

[0097] As in any embodiment above, R 3 is an unsubstituted oxyalkylene.

[0098] As in any embodiment above, R 3 is —OCH2CH2—.

[0099] As in any embodiment above, R 3 But the formula -(R a -OR b ) x -, wherein R a and R b can independently be a C1-C8 alkylene or arylene, and "x" is an integer from 1 to 500.

[0100] As in any embodiment above, R 1 and R 2 is -CH2CH2- and R 3 is -OCH2CH2- and R 4is methyl and X is a hydroxide ion or a halide ion.

[0101] As in any of the above embodiments, a surface-modified silica is provided having an average secondary particle size between about 60 nm and about 80 nm.

[0102] As in any embodiment above, a surface-modified silica is provided having a polydispersity index of about 0.07 or less.

[0103] As in any of the above embodiments, a surface-modified silica is provided having a zeta potential between about 30 mV and about 70 mV.

[0104] As in any embodiment above, a surface-modified silica is provided having an electrical conductivity of greater than 0 to about 0.25 mS / cm.

[0105] As in any embodiment above, N + / N - The surface-modified silica is provided having a molecular weight of 500 or more.

[0106] Further, as described herein, some embodiments provide a method for preparing a surface-modified silica, the method comprising: a) providing (e.g., preparing) a dispersion comprising silica and a dispersion medium; and b) mixing a quaternary ammonium-based polymer with the dispersion, thereby preparing the surface-modified silica, wherein the quaternary ammonium-based polymer is represented by Formula (I):

[0107] [ka]

[0108] [In the formula, R 1 is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted or unsubstituted heteroarylene, and substituted or unsubstituted cycloalkylene; R 2is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted or unsubstituted heteroarylene, and substituted or unsubstituted cycloalkylene; R 3 is a substituted or unsubstituted oxyalkylene, and R 4 are each independently a substituted or unsubstituted C1-C8 alkylene, X is in each case a counterion, m is an integer between 1 and 20,000, and n is an integer between 1 and 10,000. The method is a compound of variable subgroup R. 1 , R 2 , R 3 , R 4 , X, n, and m are as defined above. The quaternary ammonium polymer may be in the form of an aqueous solution. In this case, the concentration of the quaternary ammonium polymer may be, for example, 0.1 to 0.5 wt %.

[0109] It is preferable to mix silica and quaternary ammonium polymer so that the concentrations of silica and quaternary ammonium polymer in the polishing composition are as described below in C-1. Polishing composition and C-2. Polishing composition (other forms).

[0110] As in any of the above embodiments, a method is provided further comprising adding an electrolyte to the dispersion. Adding an electrolyte provides a method for controlling particle size during cationization. A list of electrolytes is provided throughout this application and may be used to prepare surface-modified silica. Non-limiting examples of electrolytes include potassium nitrate, sodium chloride, magnesium sulfate, ammonium nitrate, calcium chloride, sodium hydroxide, sodium acetate, magnesium hydroxide, and combinations thereof. In one embodiment, the electrolyte is potassium nitrate.

[0111] As in any embodiment above, a method is provided wherein the dispersion medium is water.

[0112] As in any of the above embodiments, a method is provided in which the dispersion containing silica, a quaternary ammonium-based polymer, and a dispersing medium is mixed at a speed of about 300 rpm or greater, or about 500 rpm or greater. In some embodiments, the lower limit of the mixing speed may be about 200 rpm or greater, about 250 rpm or greater, or about 300 rpm or greater. The upper limit may be about 600 rpm or less, about 500 rpm or less, about 450 rpm or less, or about 400 rpm or less.

[0113] C-1. Polishing composition The present disclosure relates to a surface-modified silica, the silica surface of which is modified with a quaternary ammonium polymer. The surface-modified silica can be used to prepare a polishing composition, and the polishing composition may further include a dispersion medium.

[0114] The polishing composition disclosed in this specification contains surface-modified silica, in which a quaternary ammonium polymer is modified (physical adsorbed) on the silica surface.By using the polishing composition containing the silica modified with a quaternary ammonium polymer to polish a substrate, it is expected that the substrate can be polished at a higher speed and with fewer defects and scratches than when unmodified silica is used.

[0115] 1. Ingredients of the polishing composition In some embodiments, the polishing composition contains a dispersion medium. In some embodiments, the dispersion medium is water. As the water, ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, etc. can be used. To reduce the amount of unwanted components present in the water, the purity of the water can be increased by operations such as removing impurity ions with an ion exchange resin, removing contaminants with a filter, and / or distillation.

[0116] In some embodiments, the water is relatively free of impurities. In some embodiments, the water contains less than about 10% w / w, about 9% w / w, about 8% w / w, about 7% w / w, about 6% w / w, about 5% w / w, about 4% w / w, about 3% w / w, about 2% w / w, about 1% w / w, about 0.9% w / w, about 0.8% w / w, about 0.7% w / w, about 0.6% w / w, about 0.5% w / w, about 0.4% w / w, about 0.3% w / w, or about 0.1% w / w of impurities, based on the total weight of the water. Examples of impurities include Na, Ca, Ni, Fe, and Al. In some embodiments, the dispersion medium may contain solvents other than water, but preferably, the dispersion medium is 80% by weight or more, 90% by weight or more, 95% by weight or more, or 99% by weight or more of water.

[0117] pH adjuster In some embodiments, the polishing composition according to the present invention contains at least one pH adjuster for controlling pH. In one embodiment, the pH adjuster is a basic compound. The basic compound can be appropriately selected from various basic compounds that have the function of increasing the pH of the polishing composition in which the compound is dissolved. For example, inorganic basic compounds such as alkali metal hydroxides, alkaline earth metal hydroxides, various carbonates, bicarbonates, etc. can be used. Such basic compounds can be used alone or in combination of two or more of them.

[0118] Specific examples of alkali metal hydroxides include potassium hydroxide, sodium hydroxide, ammonium hydroxide, etc. Specific examples of carbonates and bicarbonates include ammonium hydrogen carbonate, ammonium carbonate, potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, sodium carbonate, etc.

[0119] In an alternative embodiment, the pH adjuster may be acidic in nature. The choice of acid is not particularly limited, provided that the strength of the acid is sufficient to lower the pH of the polishing composition of the present invention.

[0120] The acidic pH adjuster may be an inorganic acid or an organic acid, for example, such inorganic acids include, but are not limited to, hydrochloric acid, sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid, and salts thereof.

[0121] For example, such organic acids include, but are not limited to, formic acid, acetic acid, chloroacetic acid, propionic acid, butanoic acid, valeric acid, 2-methylbutyric acid, N-hexanoic acid, 3,3-dimethylbutanoic acid, 2-ethylbutanoic acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, isethionic acid, 2-furancarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, and phenoxyacetic acid, and salts thereof. Such organic acids also include, but are not limited to, organic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, and isethionic acid.

[0122] The pH adjuster may be a mixture of an acidic and a basic agent (such as a buffer).

[0123] In one embodiment, the pH of the polishing vehicle or polishing composition is adjusted to a range of about 2.0 to about 10.0, about 4.0 to about 10.0, about 5.0 to about 9.0, or about 6.0 to about 8.0. In some embodiments, the pH is less than about 10.0, less than about 9.0, less than about 8.0, less than about 7.0, less than about 6.0, less than about 5.5, less than about 5.0, less than about 4.5, or less than about 4.0. In some embodiments, the pH is about 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or about 10.0. In some embodiments, the pH is greater than about 4.0, greater than about 5.0, greater than about 6.0, greater than about 7.0, greater than about 8.0, or greater than about 9.0. In some embodiments, the pH may be measured using a Thermofisher Orion Star A214.

[0124] The pH adjuster may be present in a specific concentration range, regardless of pH. For example, in some embodiments, the amount of pH adjuster is in the range of about 0.0001% to about 1% by weight, about 0.005% to about 0.5% by weight, or about 0.001% to about 0.1% by weight. In some embodiments, the amount of pH adjuster is at least about 0.0001% by weight, at least about 0.0005% by weight, at least about 0.001% by weight, at least about 0.005% by weight, at least about 0.01% by weight, at least about 0.025% by weight, at least about 0.05% by weight, at least about 0.075% by weight, or at least about 0.1% by weight. In some embodiments, the pH adjuster is present in an amount of less than about 1 wt%, less than about 0.5 wt%, less than about 0.1 wt%, less than about 0.01 wt%, less than about 0.005 wt%, less than about 0.001 wt%, or less than about 0.0005 wt%, In some embodiments, the pH adjuster is present in an amount of about 0.0001 wt%, about 0.00025 wt%, about 0.0005 wt%, about 0.0006 wt%, about 0.0007 wt%, about 0.0008 wt%, about 0.0009 wt%, about 0.001 wt%, about 0.005 wt%, about 0.0075 wt%, about 0.01 wt%, about 0.025 wt%, about 0.05 wt%, about 0.1 wt%, about 0.5 wt%, or about 1 wt%. In some embodiments, the composition (or vehicle) does not contain a pH adjuster, or contains one in an amount such that the electrical conductivity (EC) is less than 0.15 mS / cm, less than 0.1 mS / cm, or less than 0.05 mS / cm.

[0125] In some embodiments, the pH adjuster may also function as an electrolyte.

[0126] electrolyte In some embodiments, the polishing composition according to the present invention contains an electrolyte. In some embodiments, the electrolyte used herein can be used to grow the average secondary particle size (Z particle size) of the surface-modified silica. The electrolyte can reduce the absolute value of the zeta potential of the particles themselves. This has the advantage of reducing the electrostatic repulsion between the particles and polymers, making them more likely to react with the abrasive surface. It is preferable to appropriately adjust the amount of electrolyte to maintain the repulsion of the abrasive particles themselves and prevent aggregation and precipitation. In an alternative embodiment, the polishing composition does not contain an electrolyte. In some embodiments, the electrolyte may also function as a pH adjuster.

[0127] A list of electrolytes is provided throughout this application and may be used in the polishing composition. Non-limiting examples of electrolytes for use in the polishing composition include potassium nitrate, sodium chloride, magnesium sulfate, ammonium nitrate, calcium chloride, sodium hydroxide, sodium acetate, magnesium hydroxide, and combinations thereof. In one embodiment, the electrolyte is potassium nitrate.

[0128] The electrolyte may be present in an amount of about 0.01% to about 1.5%, about 0.05% to about 1.25%, or about 0.1% to about 1.0% by weight. In some embodiments, the amount of electrolyte is at least about 0.01%, at least about 0.025%, at least about 0.05%, at least about 0.1%, or at least about 0.5% by weight. In some embodiments, the electrolyte is present in an amount less than about 1.5%, less than about 1%, or less than about 0.5% by weight. In some embodiments, the electrolyte is present in an amount of about 0.01%, about 0.05%, about 0.1%, about 0.5%, or about 1% by weight. In some embodiments, the electrolyte is less than about 0.84 wt%, less than about 0.8 wt%, less than about 0.5 wt%, less than about 0.1 wt%, less than about 0.05 wt%, less than about 0.01 wt%, or less than about 0.005 wt%. In some embodiments, the composition (or vehicle) does not contain any electrolyte, or contains an amount such that the electrical conductivity (EC) is less than 0.15 mS / cm, less than 0.1 mS / cm, or less than 0.05 mS / cm.

[0129] Silica and quaternary ammonium polymer (quaternary ammonium polymer molecule) Polishing compositions containing surface-modified silica may contain silica and a quaternary ammonium-based polymer in specific amounts based on the total weight of the polishing composition. In some embodiments, the silica is present at a concentration of about 0.1 wt % to about 15 wt %, about 0.3 wt % to about 10 wt %, or about 0.5 wt % to about 7 wt % based on the total weight of the composition. A preferred content (final silica concentration) of surface-modified silica is a final silica concentration of about 5 wt %. In some embodiments, the quaternary ammonium-based polymer is present at a concentration of about 0.01 wt % to about 1.0 wt %, about 0.02 wt % to about 0.6 wt %, or about 0.03 wt % to about 0.5 wt % based on the total weight of the composition. In some embodiments, the silica is present at a concentration of about 1 wt % to about 15 wt %, about 2 wt % to about 10 wt %, or about 3 wt % to about 7 wt % based on the total weight of the composition. In some embodiments, the quaternary ammonium-based polymer is present at a concentration of about 0.1 wt % to about 1.0 wt %, about 0.2 wt % to about 0.6 wt %, or about 0.3 wt % to about 0.5 wt %, based on the total weight of the composition.

[0130] Further ingredients In one embodiment, the polishing composition disclosed herein can include additional components such as a corrosion inhibitor, an oxidizing agent, a polysaccharide, a chelating agent, a biocide, a surfactant, or a cosolvent. Additionally or alternatively, the composition disclosed herein can include other additives, as would be understood by one skilled in the art.

[0131] In one embodiment, the additional component may include a corrosion inhibitor. Non-limiting examples of corrosion inhibitors include 2-methyl-3-butyn-2-ol, 3-methyl-2-pyrazolin-5-one, 8-hydroxyquinoline, and dicyandiamide, benzotriazole and its derivatives, pyrazole and its derivatives, imidazole and its derivatives, benzimidazole and its derivatives, isocyanurate and its derivatives, and mixtures thereof. The amount of corrosion inhibitor in the polishing composition may be in the range of about 0.0005 wt% to 0.25 wt%, preferably 0.0025 wt% to 0.15 wt%, more preferably 0.005 wt% to 0.1 wt% of the corrosion inhibitor.

[0132] In another embodiment, the additional component can include an oxidizing agent. Non-limiting examples of oxidizing agents include periodic acid, hydrogen peroxide, potassium iodate, potassium permanganate, persulfates (e.g., ammonium persulfate and potassium dipersulfate), periodates (e.g., potassium periodate), ammonium molybdate, ferric nitrate, nitric acid, potassium nitrate, and mixtures thereof. The amount of oxidizing agent can range from about 0.1% to about 10% by weight, from about 0.25% to about 5% by weight, or from about 0.5% to about 1.5% by weight.

[0133] In another embodiment, the additional component can include a carbohydrate. Non-limiting examples of carbohydrates include modified cellulose ethers or complex carbohydrates. In one embodiment, the one or more polysaccharides are selected from the group consisting of hydroxyalkyl celluloses (such as methylhydroxyethyl cellulose (HEMC), methylhydroxypropyl cellulose (HPMC), hydroxyethyl cellulose (HEC), methylcellulose (MC), and hydroxypropyl cellulose (HPC)), carrageenans, gums (such as xanthan gum, guar gum, karaya gum, carrageenan gum, or pectin), sodium hyaluronate, and pullulan. The amount of carbohydrate can range from about 0.001% to about 0.2% by weight, from about 0.005% to about 0.1% by weight, or from about 0.01% to about 0.05% by weight.

[0134] In another embodiment, the additional component may include a chelating agent. The term "chelating agent" is intended to mean any substance that chelates a metal, such as copper, in the presence of an aqueous solution. Non-limiting examples of chelating agents include inorganic acids, organic acids, amines, and amino acids such as glycine and alanine, citric acid, acetic acid, maleic acid, oxalic acid, malonic acid, phthalic acid, succinic acid, nitrilotriacetic acid, iminodiacetic acid, ethylenediamine, CDTA, and EDTA.

[0135] In one embodiment, the additional component may be a biocide. Non-limiting examples of biocides include hydrogen peroxide, quaternary ammonium compounds, and chlorine compounds. More specific examples of quaternary ammonium compounds include, but are not limited to, methylisothiazolinone, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, alkylbenzyldimethylammonium chloride, and alkylbenzyldimethylammonium hydroxide, where the alkyl chain ranges from 1 to about 20 carbon atoms. More specific examples of chlorine compounds include, but are not limited to, sodium chlorite and sodium hypochlorite. Further examples of biocides include biguanides, aldehydes, ethylene oxide, isothiazolinones, iodophors, the KATHON™ and NEOLENE™ product lines available from Dow Chemicals, and the Preventol™ line from Lanxess. The amount of biocide used in the polishing composition can range from about 0.0001% to 0.10% by weight, preferably 0.0001% to 0.005% by weight, and more preferably 0.0002% to 0.0025% by weight.

[0136] In another embodiment, the additional component may include a surfactant. The surfactant may be anionic, cationic, nonionic, or zwitterionic and may increase the lubricity of the vehicle or composition. Non-limiting examples of surfactants include dodecyl sulfate, sodium or potassium salts, lauryl sulfate, secondary alkane sulfonates, alcohol ethoxylates, acetylene diol surfactants, quaternary ammonium surfactants, amphoteric surfactants such as betaine and amino acid derivative surfactants, and any combination thereof. Examples of suitable commercially available surfactants include surfactants from Dow Chemicals in the TRITON™, Tergitol™, and DOWFAX™ families, as well as various surfactants from Air Products and Chemicals in the SURFYNOL™, DYNOL™, Zetasperse™, Nonidet™, and Tomadol™ surfactant families. Suitable surfactants among surfactants may also include polymers containing ethylene oxide (EO) and propylene oxide (PO) groups. An example of an EO-PO polymer is Tetronic™ 90R4 from BASF Chemicals. An example of an acetylenic diol surfactant is Dynol™ 607 from Air Products and Chemicals. The amount of surfactant used in the polishing composition can be in the range of about 0.0005 wt % to 0.15 wt %, preferably 0.001 wt % to 0.05 wt %, and more preferably 0.0025 wt % to 0.025 wt %.

[0137] In another embodiment, the additional component may be a solvent called a cosolvent. This cosolvent is present in addition to the dispersion medium described above. Non-limiting examples of cosolvents include, but are not limited to, methanol or ethanol, ethyl acetate, tetrahydrofuran, dimethylformamide, toluene, acetone, etc. Other non-limiting examples of cosolvents include dimethyl sulfoxide, pyridine, acetonitrile, glycol, and mixtures thereof. Cosolvents may be used in various amounts, preferably from lower limits of about 0.0001, 0.001, 0.01, 0.1, 0.5, 1, 5, or 10% (by weight) to upper limits of about 0.001, 0.01, 0.1, 1, 5, 10, 15, 20, 25, or 35% (by weight).

[0138] As described herein, the polishing composition has certain properties that are greatly influenced by the components in the composition, both in type and amount. Thus, certain materials may need to be excluded from the composition to maintain the desired properties.

[0139] 2. Preparation of Polishing Composition In some embodiments, a method for preparing a polishing composition comprising surface-modified silica and a dispersing medium is provided. The method for preparing the polishing composition comprises mixing the surface-modified silica with the dispersing medium.

[0140] The mixing method is not particularly limited, and for example, it is sufficient that this method is carried out by stirring and mixing the surface-modified silica and the dispersion medium. The surface-modified silica may be in the form of an aqueous dispersion, and the modified silica abrasive liquid (silica abrasive liquid coexisting with quaternary ammonium-based polymer molecules) before being prepared into a polishing composition may also be referred to as a vehicle in this specification. In some embodiments, the vehicle does not contain a pH adjuster. The surface-modified silica is prepared before preparing the polishing composition. However, the order in which the surface-modified silica is added to other components in the polishing composition is not particularly limited. Furthermore, the polishing composition can be produced in a state in which aggregation of the surface-modified silica is suppressed.

[0141] The temperature used when mixing the components is not particularly limited, but is generally in the range of about 5°C to about 50°C. In some embodiments, the temperature is in the range of about 10°C to about 40°C or about 20°C to about 30°C. In some embodiments, the temperature is about 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C. Heating may be performed to increase the dissolution rate. The mixing time is also not particularly limited.

[0142] Thus, as described herein, some embodiments are polishing compositions comprising the surface-modified silica disclosed herein and a dispersing medium.

[0143] In some embodiments, the polishing composition may contain silica (surface-modified silica) present at a concentration of about 0.1 wt. % to about 15 wt. %, about 0.5 wt. % to about 10 wt. %, or about 1.0 wt. % to about 5 wt. % based on the total weight of the composition. In some embodiments, the amount of silica may be about 0.1 wt. % or more, about 0.3 wt. % or more, about 0.5 wt. % or more, about 1 wt. % or more, about 2 wt. % or more, about 3 wt. % or more, about 4 wt. % or more, or about 10 wt. % or more based on the total weight of the composition. In other embodiments, the amount of silica is less than about 15 wt. % or less, about 10 wt. % or less, about 6 wt. % or less, about 5 wt. % or less, about 4 wt. % or less, or about 3 wt. The descriptions of these embodiments are also applicable to C-2 Polishing Composition (other forms). The following embodiments may also be similarly applied.

[0144] The polishing composition, in some embodiments, may comprise a quaternary ammonium-based polymer present in a concentration of about 0.01 wt % to about 1.0 wt %, about 0.05 wt % to about 0.8 wt %, about 0.1 wt % to about 0.6 wt %, or about 0.15 wt % to about 0.40 wt %, based on the total weight of the composition. The polishing composition, in some embodiments, may comprise a quaternary ammonium-based polymer present in a concentration of about 0.02 wt % to about 1.0 wt %, about 0.1 wt % to about 0.8 wt %, about 0.25 wt % to about 0.6 wt %, or about 0.125 wt % to about 0.40 wt %, based on the total weight of the composition.

[0145] In some embodiments, the amount of quaternary ammonium-based polymer can be about 0.01 wt.% or more, about 0.1 wt.% or more, about 0.2 wt.% or more, about 0.4 wt.% or more, or about 0.6 wt.% or more, based on the total weight of the composition. In other embodiments, the amount of quaternary ammonium-based polymer is less than about 1.0 wt.%, less than about 0.7 wt.%, less than about 0.5 wt.%, less than about 0.4 wt.%, or less than about 0.25 wt.% based on the total weight of the composition.

[0146] The polishing composition may have an associated electrical conductivity (EC). The electrical conductivity of the polishing composition described herein is greater than 0 to about 1.0 mS / cm. In some embodiments, the electrical conductivity is greater than 0 to about 0.75 mS / cm, greater than 0 to about 0.50 mS / cm, greater than 0 to about 0.25 mS / cm, greater than 0 to about 0.15 mS / cm, greater than 0 to about 0.10 mS / cm, greater than 0 to about 0.05 mS / cm, or greater than 0 to about 0.03 mS / cm. In some embodiments, the electrical conductivity is about 0.01 mS / cm to about 1.0 mS / cm, about 0.02 mS / cm to about 0.50 mS / cm, or about 0.03 mS / cm to about 0.1 mS / cm. In some embodiments, the electrical conductivity is about 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, or 0.15 mS / cm. In some embodiments, the upper limit of the electrical conductivity is about 0.25 mS / cm, about 0.20 mS / cm, about 0.18 mS / cm, about 0.16 mS / cm, about 0.14 mS / cm, about 0.12 mS / cm, about 0.10 mS / cm, about 0.08 mS / cm, about 0.07 mS / cm, about 0.06 mS / cm, about 0.05 mS / cm, about 0.04 mS / cm, or about 0.03 mS / cm.

[0147] The polishing composition may have an associated zeta potential. The zeta potential may be positive or negative. In one embodiment, the polishing composition has a positive zeta potential. For example, in some embodiments, the zeta potential is greater than or equal to +30 mV in the pH range of 3 to 10. Furthermore, the greater the amount of quaternary ammonium-based surface-modified silica present in the polishing composition, the higher the pH range over which the zeta potential remains positive.

[0148] The positive zeta potential can be in the range of about 10 mV to about 90 mV, about 20 mV to about 80 mV, about 30 mV to about 70 mV, or about 40 mV to about 60 mV. In some embodiments, the zeta potential is about 30 mV, about 35 mV, about 40 mV, about 45 mV, about 50 mV, about 55 mV, about 60 mV, about 65 mV, or about 70 mV. In some embodiments, the zeta potential is greater than about 20 mV, greater than about 30 mV, greater than about 40 mV, or greater than about 50 mV.

[0149] C-2. Polishing composition (other forms) Another embodiment includes silica particles and quaternary ammonium-based polymer molecules, wherein the quaternary ammonium-based polymer molecules have the formula (N + / N - ) is 500 or more.

[0150] The silica particles coexisting with the quaternary ammonium-based polymer molecules in the composition (sometimes referred to as "coexisting," as used herein) may have an average secondary particle diameter of about 10 nm or more, about 25 nm or more, about 50 nm or more, about 60 nm or more, or about 70 nm or more. Alternatively, or in addition, the silica particles may have an average secondary particle diameter of about 500 nm or less, about 200 nm or less, about 150 nm or less, about 100 nm or less, about 90 nm or less, about 80 nm or less, about 70 nm or less, or about 60 nm or less. For example, in embodiments, the silica particles may have an average secondary particle diameter ranging from about 10 nm to about 500 nm, about 25 nm to about 250 nm, about 50 nm to about 100 nm, or about 60 nm to about 80 nm. In some embodiments, the average secondary particle diameter is about 50 nm, about 60 nm, about 70 nm, about 80 nm, or about 90 nm.

[0151] Preferred embodiments of the secondary particle diameter range include a range of about 50 nm to about 100 nm, or about 60 nm to about 80 nm. A more preferred range is about 60 nm to about 80 nm. When the average secondary particle diameter is within this preferred range, surface defects such as scratches on the substrate surface can be suppressed.

[0152] The average secondary particle size of the silica particles coexisting with the quaternary ammonium-based polymer molecules in the composition can be measured by dynamic light scattering (DLS). As used herein, the average secondary particle size is also referred to as the "z-average size."

[0153] In particle size distribution analysis by dynamic light scattering, the polydispersity index (PDI) is another widely used measurement. Generally speaking, the higher the PDI value, the wider the particle size distribution. Therefore, a lower PDI value is desirable. In some embodiments, the PDI of the silica particles coexisting with the quaternary ammonium-based polymer molecules in the composition is in the range of about 0 to about 0.20, about 0 to about 0.10, or about 0 to about 0.05. Alternatively, the PDI is in the range of about 0.01 to about 0.20, about 0.025 to about 0.15, or about 0.05 to about 0.10. In some embodiments, the PDI is less than about 0.15, less than about 0.10, less than about 0.75, less than about 0.70, or less than about 0.50. In some embodiments, the polydispersity index (PDI) may be measured using a Malvern Zetasizer.

[0154] The silica particles that coexist with quaternary ammonium polymer molecules in the composition have a permanent positive charge.The charge on such particles is generally referred to in the art as zeta potential (or interfacial potential).The zeta potential of particles refers to the potential difference between the charge of the ions surrounding the particles and the charge of the bulk solution of the polishing composition (for example, the liquid carrier and any other components dissolved therein).

[0155] The above description can be similarly applied to the specific description of the quaternary ammonium polymer (quaternary ammonium polymer molecule).

[0156] Thus, silica coexisting with quaternary ammonium-based polymer molecules in the composition has an associated zeta potential. In one embodiment, silica coexisting with quaternary ammonium-based polymer molecules in the composition has a positive zeta potential. In some embodiments, silica coexisting with quaternary ammonium-based polymer molecules has a positive zeta potential when in the polishing composition. The positive zeta potential can be in the range of about 10 mV to about 90 mV, about 20 mV to about 80 mV, about 30 mV to about 70 mV, or about 40 mV to about 60 mV. In some embodiments, the zeta potential is about 30 mV, about 35 mV, about 40 mV, about 45 mV, about 50 mV, about 55 mV, about 60 mV, about 65 mV, or about 70 mV. In some embodiments, the zeta potential is greater than about 20 mV, greater than about 30 mV, greater than about 40 mV, or greater than about 50 mV. In some embodiments, the zeta potential may be measured using a Malvern Zetasizer.

[0157] The silica present in the composition with the quaternary ammonium-based polymer molecules may have an associated electrical conductivity (EC). The electrical conductivity of the silica present in the composition with the quaternary ammonium-based polymer molecules is greater than 0 to about 1.0 mS / cm. In some embodiments, the electrical conductivity is greater than 0 to about 0.75 mS / cm, greater than 0 to about 0.50 mS / cm, greater than 0 to about 0.25 mS / cm, greater than 0 to about 0.15 mS / cm, greater than 0 to about 0.10 mS / cm, greater than 0 to about 0.05 mS / cm, or greater than 0 to about 0.03 mS / cm. In some embodiments, the electrical conductivity is about 0.01 mS / cm to about 1.0 mS / cm, about 0.02 mS / cm to about 0.50 mS / cm, or about 0.03 mS / cm to about 0.1 mS / cm. In some embodiments, the electrical conductivity is about 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, or 0.15 mS / cm. In some embodiments, the upper limit of the electrical conductivity is about 0.25 mS / cm, about 0.20 mS / cm, about 0.18 mS / cm, about 0.16 mS / cm, about 0.14 mS / cm, about 0.12 mS / cm, about 0.10 mS / cm, about 0.08 mS / cm, about 0.07 mS / cm, about 0.06 mS / cm, about 0.05 mS / cm, about 0.04 mS / cm, or about 0.03 mS / cm. In some embodiments, the electrical conductivity may be measured using a Thermofisher Scientific, Orion Star A212.

[0158] In some embodiments, the silica present in the composition with the quaternary ammonium-based polymer molecules is present at a concentration of about 1 wt % to about 15 wt %, about 2 wt % to about 10 wt %, or about 3 wt % to about 7 wt %, based on the total weight of the composition. A preferred content (final silica concentration) of silica present in the composition with the quaternary ammonium-based polymer molecules is about 5 wt %.

[0159] Silica particles coexisting with quaternary ammonium-based polymer molecules in a composition can be further characterized by the relationship of the quaternary ammonium-based polymer molecules to the silica particles. This relationship is herein referred to as (N + / N - ) where a higher number indicates a more complete coating of the silica particles. Thus, in some embodiments, N + / N - The value is about 500 or greater, greater than about 500, greater than about 1,000, greater than about 2,000, greater than about 3,000, greater than about 4,000, greater than about 5,000, greater than about 6,000, or greater than about 7,000. + / N - The value is about 500, about 1,000, about 2,500, about 5,000, or about 7,000.

[0160] In another embodiment, a method for preparing a polishing composition includes a step of mixing a dispersion containing silica and a dispersion medium with an aqueous solution of a quaternary ammonium polymer. This step may be performed in advance before preparing a polishing composition by further adding other components such as a pH adjuster. In this step, the dispersion containing silica, a quaternary ammonium polymer, and a dispersion medium is mixed at a speed of about 300 rpm or more, or about 500 rpm or more, or by using, for example, N + / N - The value may be appropriately set to about 500 or more, or similar steps may be performed as described in the method for preparing surface-modified silica. In some embodiments, the lower limit of the mixing speed may be about 200 rpm or more, about 250 rpm or more, or about 300 rpm or more. The upper limit may be about 500 rpm or less, about 450 rpm or less, or about 400 rpm or less. In some embodiments, N + / N - The value is about 500 or greater, greater than about 500, greater than about 1,000, greater than about 2,000, greater than about 3,000, greater than about 4,000, greater than about 5,000, greater than about 6,000, or greater than about 7,000. + / N -The value is about 500, about 1,000, about 2,500, about 5,000, or about 7,000.

[0161] For other explanations regarding the polishing composition in C-2, the explanations described in C-1. Polishing composition can be applied as would be commonly understood by a person skilled in the art, such as appropriately replacing surface-modified silica with silica as necessary.

[0162] D. Polishing method In one embodiment, the polishing composition described herein is useful for polishing any suitable substrate.Suitable substrates include, but are not limited to, flat panel displays, integrated circuits, memory or rigid disks, metals, interlayer dielectric (ILD) devices, semiconductors, microelectromechanical systems, ferroelectrics, and magnetic heads.

[0163] The polishing method may include using a polishing apparatus. The polishing apparatus is not particularly limited. Generally, the polishing apparatus has a holder for holding a substrate or an object to be polished, a movable polishing head, a motor with variable rotation speed, and a polishing plate to which a polishing pad (or polishing cloth) can be attached.

[0164] The polishing conditions are not particularly limited. For example, the rotation speeds of the polishing plate and head are each independently 10 to 500 rpm. The polishing pad and / or polishing head will be applied to the substrate at a specific pressure, preferably 0.5 to 10 psi. The method for supplying the polishing composition to the polishing pad is not particularly limited. For example, the polishing composition can be continuously supplied using a pump or the like. The supply amount is not limited, but it is preferable to cover the surface of the polishing pad seamlessly with the polishing composition.

[0165] In a method for polishing a substrate, the polishing composition disclosed herein has a material removal rate of at least about 100 Å / min, at least about 150 Å / min, at least about 180 Å / min, at least about 200 Å / min, at least about 250 Å / min, at least about 300 Å / min, or at least about 500 Å / min. In some embodiments, the material removal rate is in the range of about 100 Å / min to about 500 Å / min, about 150 Å / min to about 300 Å / min, or about 180 Å / min to about 250 Å / min. In some embodiments, the material removal rate is about 100 Å / min, about 150 Å / min, about 180 Å / min, about 200 Å / min, about 250 Å / min, or about 300 Å / min.

[0166] Thus, in some embodiments, the present specification describes a method for polishing a substrate, the method comprising the steps of: a) providing a polishing composition containing surface-modified silica; and b) polishing the substrate with the polishing composition to provide a polished substrate.

[0167] As in any embodiment above, a method is provided wherein the substrate is a semiconductor.

[0168] As in any of the above embodiments, a method is provided that results in an oxide removal rate of at least about 500 Å / min.

[0169] When implementing the polishing method disclosed herein, which includes the use of surface-modified silica surface-modified with a quaternary ammonium-based polymer, improvements are observed compared to known methods. For example, in one embodiment, a higher removal rate was observed for materials (i.e., substrates) with a negative zeta potential. For example, SiO2 has a zeta potential of -30 mV at pH = 7. In this case, there is an attractive force between the abrasive (i.e., surface-modified silica) and the wafer. Specifically, this effect is also applicable to many CMP materials (e.g., SiN, SoC, W, Cu, Ta, Co, etc.).

[0170] E. Working Example The following preparations and examples are given to enable those skilled in the art to more clearly understand and to practice the present invention, and should not be construed as limiting the scope of the invention, but merely as illustrative and representative thereof.

[0171] In one aspect, a method for making surface-modified silica is disclosed. In another aspect, a method for polishing a material using a polishing composition comprising the surface-modified silica is disclosed.

[0172] Example 1: Example of surface-modified silica We have identified surface-modified silicas that enable high zeta potentials with minimal change in average secondary particle size. More specifically, in some embodiments, 2-5 wt. % SiO2 materials can be produced with a zeta potential of approximately +50 mV with minimal change in average secondary particle size. In further embodiments, small amounts of electrolyte can be used to grow the particle size.

[0173] More specifically, a dispersion containing silica (silica particles) and a dispersant (z-average diameter (nm) of silica: 70 nm) was prepared, and this was mixed with an aqueous solution of a quaternary ammonium-based polymer shown in Table 1 using an Ultra Turrax 18G rotor / stator at 300 rpm to prepare a modified silica abrasive liquid (silica abrasive liquid coexisting with quaternary ammonium-based polymer molecules) (vehicle). Subsequently, optionally, a dispersant (water) and potassium nitrate shown in Table 1 were added, and the mixture was mixed at 300 rpm using an Ultra Turrax 18G rotor / stator to prepare a composition having the composition shown in Table 1. The z-average diameter, PDI, and zeta potential (mV) of the silica (modified silica) in each composition, as well as the EC (mS / cm) of the composition, were measured using the measurement methods specified in the specification, and are shown in Table 2.

[0174] [Table 1]

[0175] [Table 2]

[0176] POEDMIED2C is defined herein. PDADMAC has the following chemical structure:

[0177] [ka]

[0178] In addition, N + / N - The value of is calculated using the following formula:

[0179]

number

[0180] index=4.4x 10 8 g / mol.

[0181] Example 2: Procedure for preparing surface-modified silica The surface modification of silica can be carried out by mixing a polymer-containing solution with a suspension containing silica. Mixing additives while pumping the solution (in situ mixing) is the preferred method for large-scale processing, but mixing can also be achieved by rotor / stator methods, blade stirring, or by pouring one liquid into the other and then repeatedly pouring the mixture between two containers. The polymer-containing solution can be an aqueous polymer solution.

[0182] To treat particles with a quaternary ammonium-based polymer, a particle suspension is mixed with a polymer solution. The particles are silica particles. The polymer solution can be an aqueous polymer solution. The lower limit of the speed for mixing the liquid containing the particle suspension and the polymer (polymer solution) is preferably about 200 rpm or more, about 250 rpm or more, or about 300 rpm or more. The upper limit is preferably about 500 rpm or less, about 450 rpm or less, or about 400 rpm or less. Mixing can be performed by methods known in the art, such as using an Ultra Turrax 18G rotor / stator at about 250 rpm or more. In some embodiments, the speed for mixing the liquid containing the particle suspension and the polymer (polymer solution) can be 250 to 500 rpm.

[0183] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

[0184] The entire disclosure of U.S. Provisional Application No. 63 / 168789, filed March 31, 2021, is incorporated by reference in its entirety.

Claims

1. A surface-modified silica comprising silica and a quaternary ammonium-based polymer, wherein the quaternary ammonium-based polymer has the formula (I): 【Chemistry 1】 During the ceremony, R １ is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted heteroarylene, and substituted cycloalkylene; R ２ is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted heteroarylene, and substituted cycloalkylene; R ３ is unsubstituted oxyalkylene, R ４ are each independently substituted or unsubstituted C1-C8 alkyl; X is in each case a counterion, m is an integer between 1 and 20,000; n is an integer between 1 and 10,000 wherein the weight average molecular weight of the quaternary ammonium polymer is 1,000 g / mol to 8,000 g / mol and the polydispersity index (PDI) is less than 0.

15.

2. 2. The surface-modified silica according to claim 1, wherein each X is independently selected from the group consisting of hydroxide ion, halide ion, nitrate ion, carbonate ion, sulfate ion, phosphate ion, and acetate ion.

3. R １ and R ２ are each independently substituted or unsubstituted C1-C8 alkylene, and R ４ The surface-modified silica according to claim 1 or 2, wherein each of is independently a substituted or unsubstituted C1 to C8 alkyl.

4. R １ and R ２ are each independently an unsubstituted C1-C4 alkylene; R ４ The surface-modified silica according to claim 3, wherein each is independently an unsubstituted C1-C4 alkyl.

5. The surface-modified silica according to claim 1, wherein the quaternary ammonium polymer has a weight-average molecular weight of between 3,000 g / mol and 7,000 g / mol.

6. 6. The surface-modified silica according to claim 5, wherein the quaternary ammonium-based polymer has a weight-average molecular weight between 4,000 g / mol and 7,000 g / mol.

7. The surface-modified silica according to claim 1, having an average secondary particle diameter of 60 nm to 80 nm.

8. The surface-modified silica according to claim 1, having a polydispersity index of 0.07 or less.

9. The surface-modified silica of claim 1, having a zeta potential between 30 mV and 70 mV.

10. A polishing composition comprising the surface-modified silica according to any one of claims 1 to 9 and a dispersion medium.

11. 11. The polishing composition of claim 10, wherein the quaternary ammonium-based polymer is present at a concentration of 0.2% to 0.6%, based on the total weight of the composition.

12. The polishing composition according to claim 10 or 11, having a pH of 5 to 9.

13. The polishing composition according to any one of claims 10 to 12, further comprising a pH adjuster.

14. 1. A method for polishing a substrate, comprising: a) preparing the polishing composition according to any one of claims 10 to 13; b) polishing the substrate with the polishing composition to provide a polished substrate; A method comprising:

15. 1. A method for preparing surface-modified silica, comprising: a) preparing a dispersion comprising silica and a dispersion medium; b) mixing an aqueous solution of a quaternary ammonium polymer with the dispersion; thereby preparing the surface-modified silica. Including, The quaternary ammonium-based polymer has the formula (I): 【Chemistry 2】 During the ceremony, R １ is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted heteroarylene, and substituted cycloalkylene; R ２ is selected from substituted or unsubstituted C1-C8 alkylene, substituted or unsubstituted arylene, substituted heteroarylene, and substituted cycloalkylene; R ３ is unsubstituted oxyalkylene, R ４ are each independently substituted or unsubstituted C1-C8 alkyl; X is in each case a counterion, m is an integer between 1 and 20,000; n is an integer between 1 and 10,000; wherein the weight average molecular weight of the quaternary ammonium-based polymer is 1,000 g / mol to 8,000 g / mol, and the polydispersity index (PDI) of the surface-modified silica is less than 0.15.

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