Polishing composition based on a mixture of colloidal silica particles

Abstract

To provide a novel CMP composition capable of efficiently and selectively polishing a HfO2 and / or a SiO2 film.SOLUTION: The present specification provides a composition containing a first colloidal silica particle of which a surface is not modified and a second colloidal silica particle of which the surface is modified to be charged in a negative electrode.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present technology relates generally to compositions and methods for selective removal of HfO2 or SiO2 from surfaces containing HfO2 and / or SiO2. [Background technology]

[0002] One of the major chemical mechanical polishing (CMP) challenges for semiconductor manufacturing is to selectively polish certain materials. Silicon dioxide (SiO2) is widely used in semiconductors and other electronic materials. Hafnium oxide (HfO2) is also used in semiconductors, for example as a high-K material in FinFETs (Fin Field Effect Transistors) and as a ferroelectric material in new emerging designs [J.Muller,et al.,Ferroelectric Hafnium Oxide Based Materials and Devices:Assessment of Current Status and Future Prospects,ECS J.Solid State Sci.Technol.2015 4(5):N30-N35;J.Muller,et al.,Integration Challenges of Ferroelectric Hafnium Oxide Based Embedded Memory,ECS Trans.2015 69(3):85-95]. Slurries for polishing HfO2 have been reported [Y. Feng, et al., Exploration of Novel Slurry on Hafnium Oxide Films Chemical Mechanical Planarization, ECS Trans. 2014 60(1):647-652; K. Zhang, et al., Optimization and Mechanism on Chemical Mechanical Planarization of Hafnium Oxide for RRAM Devices, ECS J. Solid State Sci. Technol. 2014 3(7):P249-P252].

[0003] The electronic materials can include HfO2 and SiO2. However, different materials such as HfO2 and SiO2 have different physical and chemical properties and may exhibit different selectivities when polishing. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there is a need for new CMP compositions that can efficiently and selectively polish HfO2 and / or SiO2 films. [Means for solving the problem]

[0005] Provided herein are compositions comprising a mixture of colloidal silica particles and methods for polishing a surface comprising a HfO2 and / or SiO2 film.

[0006] Embodiments include CMP compositions comprising first colloidal silica particles and second colloidal silica particles, where the first colloidal silica particles are not surface modified and the second colloidal silica particles are surface modified and negatively charged. In some embodiments, the pH of the composition is 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, or 6.2 or less (e.g., 3.2 or less). In some embodiments, the first colloidal silica particles and the second colloidal silica particles have substantially the same primary particle size and substantially the same secondary particle size. In some embodiments, the primary particle size of the first and second colloidal silica particles is about 10-90 nm and the secondary particle size of the first and second colloidal silica particles is about 20-220 nm. In some embodiments, the weight ratio of the first colloidal silica particles to the second colloidal silica particles is about 2:0.01 to 1:1. In some embodiments, the weight ratio of the first colloidal silica particles to the second colloidal silica particles is about 1:1 to 2:0.01. In some embodiments, the composition comprises first colloidal silica particles, second colloidal silica particles, water, a pH adjuster, and optionally one or more of a preservative, a biocide, a polymer, and a surfactant. In some embodiments, the first colloidal silica particles are present in an amount of greater than 0% to about 5% by weight. In some embodiments, the second colloidal silica particles are present in an amount of greater than 0% to about 5% by weight. In some embodiments, the first colloidal silica particles have a zeta potential of about -5 mV at pH 3.2 and the second colloidal silica particles have a zeta potential of -30 mV or more negative at pH 3.2.

[0007] Other embodiments include a method of selectively increasing the removal rate of HfO2 from a surface comprising HfO2 or SiO2, the method comprising contacting the surface with a slurry comprising first colloidal silica particles and second colloidal silica particles, the first colloidal silica particles being unmodified and the second colloidal silica particles being surface modified and negatively charged, and the pH of the composition being 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, or 6.2 or less (e.g., 3.2 or less). In some embodiments, the removal rate of HfO2 and SiO2 is 10:1 or more. In some embodiments, the weight ratio of the first colloidal silica particles to the second colloidal silica particles is greater than 3:1. In some embodiments, the removal rate of HfO2 is 1000 Å / min or more. In some embodiments, the first colloidal silica particles are present in an amount of greater than 0% to about 5% by weight. In some embodiments, the second colloidal silica particles are present in an amount of greater than 0% to about 5% by weight. In some embodiments, the slurry comprises the first colloidal silica particles, the second colloidal silica particles, water, a pH adjuster, and optionally one or more of a preservative, a biocide, a polymer, and a surfactant.

[0008] Other embodiments include a method of selectively removing HfO2 or SiO2 from a surface containing HfO2 and SiO2, comprising contacting the surface with a slurry comprising first colloidal silica particles and second colloidal silica particles, the first colloidal silica particles being unmodified and the second colloidal silica particles being surface modified and negatively charged, the pH of the composition being 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, or 6.2 or less (e.g., 3.2 or less), and adjusting the weight ratio of the first colloidal silica particles to the second colloidal silica particles to selectively remove HfO2 and / or SiO2. In some embodiments, the weight ratio of the first colloidal silica particles to the second colloidal silica particles is greater than 3:1. In some embodiments, the weight ratio of the first colloidal silica particles to the second colloidal silica particles is less than 3:1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Provided herein is a method for polishing a surface comprising a CMP composition and a HfO2 and / or SiO2 film. As used herein, the term "chemical mechanical polishing" or "planarization" refers to a method for planarizing (polishing) a surface by a combination of surface chemical reaction and mechanical polishing. In some embodiments, the chemical reaction is initiated by applying a composition (interchangeably referred to as "polishing slurry", "polishing composition", "slurry composition" or simply "slurry") to the surface that can react with the surface material, thereby simultaneously transforming the surface into a product that can be more easily removed by mechanical polishing. In some embodiments, the mechanical polishing is performed by contacting a polishing pad with the surface and moving the polishing pad against the surface.

[0010] composition The CMP polishing compositions disclosed herein can comprise, consist essentially of, or consist of one or more of the following components:

[0011] Abrasive grain The CMP compositions of the present disclosure include at least two different colloidal silica particle abrasives. In some embodiments, a first colloidal silica particle is not surface-modified and a second colloidal silica particle is surface-modified and negatively charged.

[0012] Ordinary colloidal silica has a zeta potential value close to zero under acidic conditions. Surface-modified negatively charged silica particles can be, for example, structured to easily form anions in the acidic or neutral region. Several methods are known to produce surface-modified negatively charged silica particles. For example, colloidal silica with an organic acid immobilized thereon. In particular, colloidal silica with an organic acid immobilized thereon is preferred. The organic acid is immobilized on the colloidal silica by chemically bonding the functional group of the organic acid to the colloidal silica surface. When the purpose is to immobilize sulfonic acid, which is one of the organic acids, on colloidal silica, the immobilization can be carried out, for example, by the method described in “Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem.Commun.246-247 (2003). Specifically, colloidal silica with sulfonic acid immobilized on its surface can be obtained by combining a silane coupling agent with a thiol group, such as 3-mercaptopropyltrimethoxysilane, with the colloidal silica and oxidizing the thiol group with hydrogen peroxide. Alternatively, when a carboxylic acid is to be immobilized on colloidal silica, the immobilization can be carried out by, for example, the method described in "Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel", Chemistry Letters, 3, 228-229 (2000). Specifically, colloidal silica having a carboxylic acid immobilized on its surface can be obtained by combining a silane coupling agent containing a photolabile 2-nitrobenzyl ester with colloidal silica and irradiating the colloidal silica with light.

[0013] In some embodiments, the colloidal silica particles are surface modified to be negatively charged under acidic conditions, for example, at a pH of less than 7, 6, 5, 4, 3, or 2. In some embodiments, the negative charge under acidic conditions is, for example, about -10, -20, -30, -40, -50 mV or more negative. In some embodiments, the negative charge under acidic conditions is more negative (i.e., more negative) than the corresponding unmodified colloidal silica under the same pH.

[0014] In some embodiments, the colloidal silica has a defined primary particle size and / or a defined secondary particle size. It is understood that agglomerated particles may be produced from a combination of individual particles, these individual particles being known in the art as primary particles, while the agglomerated combination of particles is known in the art as secondary particles.

[0015] In some embodiments, the colloidal silica particles have an average primary particle size (D) of less than 100 nm, e.g., a size of about 10-90 nm. P1 In some embodiments, the colloidal silica particles have an average primary particle size (D) of about 10 to 120 nm, e.g., about 10, about 15, about 20, about 25, about 30, about 40, about 50, about 60, about 70, about 80, about 90, about 100, about 110 nm, or about 120 nm, or any range therebetween. P1 ) The average primary particle diameter of the abrasive grains (D P1 ) for example, using the formula D P1 The specific surface area S (m 2 The specific surface area of ​​the abrasive grains can be determined from the specific surface area (g / g). The specific surface area of ​​the abrasive grains can be measured, for example, by using a surface area measuring device under the trade name "FLOW SORB II 2300" manufactured by Micromeritics.

[0016] The average secondary particle diameter of colloidal silica (D P2) is not particularly limited. From the viewpoint of polishing rate, etc., the average secondary particle diameter is preferably 20, 30, 40, 50, 60, 65, 70, 75, 80, 90, 100, 150, 200 nm or more. In some embodiments, the secondary particle diameter of the colloidal silica is about 20, 30, 40, 50, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190, 200, 210, 220 nm, or a diameter in the range therebetween. In some embodiments, the colloidal silica particles have an average secondary particle diameter (D P2 In some embodiments, the colloidal silica particles have a secondary particle size that is about (e.g., within 10%, 15%, or 20%) twice the size of the primary particle size.

[0017] Average secondary particle size of colloidal silica D P2 can be measured, for example, by dynamic light scattering using a model "UPA-UT151" from Nikkiso Co., Ltd., for an aqueous dispersion of the target abrasive grain as a measurement sample (the dispersion includes a composition that does not include a water-soluble polymer).

[0018] In some embodiments, the first colloidal silica particles and the second colloidal silica particles have substantially the same primary particle size and / or substantially the same secondary particle size. In some embodiments, the difference between the primary particle size and / or secondary particle size of the first colloidal silica particles and the second colloidal silica particles is less than 20%, less than 10%, or less than 5%. In some embodiments, the first colloidal silica particles and the second colloidal silica particles have different primary particle sizes and / or different secondary particle sizes, each size being independently selected from those described herein.

[0019] In some embodiments, the present CMP compositions comprise from greater than 0% to about 5% by weight of a first colloidal silica particle abrasive and from greater than 0% to about 5% by weight of a second colloidal silica particle abrasive. For example, the CMP composition may comprise about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0 weight percent of the first colloidal silica particles. % of a second colloidal silica particle abrasive and about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0 weight percent of a second colloidal silica particle abrasive.

[0020] In some embodiments, the weight ratio of the first colloidal silica particles to the second colloidal silica particles is about 2:0.01 to 1:1. In other embodiments, the weight ratio of the first colloidal silica particles to the second colloidal silica particles is about 1:1 to 2:0.01. The weight ratio of the first colloidal silica particles to the second colloidal silica particles can be, for example, 2:0.01; 10:1; 9:1; 8:1; 7:1; 6:1; 5:1; 4:1; 3:1; 2:1; 1:1, 1:2; 1:3; 1:4; 1:5; 1:6; 1:7; 1:8; 1:9; or 1:10. solvent In some embodiments, the CMP composition disclosed herein includes one or more solvents. The solvent of the CMP slurry is not particularly limited. In some embodiments, the solvent is water, such as deionized water, a protic or aprotic organic solvent, such as alcohols (e.g., methanol, ethanol, or isopropanol), or a mixture of two or more thereof.

[0021] pH adjuster In some embodiments, the CMP composition further comprises at least one pH adjuster. In some embodiments, the pH of the CMP composition is less than 7, e.g., within the range of about 1 to about 6, inclusive of the endpoints. For example, in some embodiments, the pH of the CMP composition is about 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, or 6.2, or any range therebetween.

[0022] In some embodiments, acid is used as pH adjusting agent.The acid used in the context of the present disclosure can be organic or inorganic.Acid includes inorganic acids such as sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid; and organic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric 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, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid, and organic sulfonic acids including methanesulfonic acid, ethanesulfonic acid, and isethionic acid.

[0023] The content of the acid in the CMP composition is not particularly limited, so long as it is an amount that brings the CMP composition into the aforementioned pH range.

[0024] Other Ingredients The CMP compositions of the present invention may optionally contain other ingredients such as preservatives, biocides, polymers, and surfactants, or the like.

[0025] In some embodiments, water-soluble polymers may be added to the CMP composition to improve the hydrophilicity of the surface to be polished or to increase the dispersion stability of the abrasive grains. Examples of water-soluble polymers include cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose (HEC), hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, or carboxymethylcellulose; imine derivatives such as poly(N-acylalkyleneimine); polyvinyl alcohol; modified (cationically or non-ionically modified) polyvinyl alcohol; polyvinylpyrrolidone; polyvinylcaprolactam; polyoxyalkylene such as polyoxyethylene; and copolymers containing these structural units. The water-soluble polymers may be used alone or in a mixture of two or more.

[0026] In some embodiments, the CMP compositions according to the present disclosure may include a biocide or other preservative. Preservatives and biocides that may be used in connection with the present invention include isothiazolin-based preservatives such as 2-methyl-4-isothiazolin-3-one or 5-chloro-2-methyl-4-isothiazolin-3-one, paraoxybenzoic acid esters, and phenoxyethanol. These preservatives and biocides may be used either alone or in mixtures of two or more.

[0027] In some embodiments, the CMP composition does not include an azole compound. In some embodiments, the CMP composition does not include a compound having a triazole, pyrazole, imidazole, thiazole, oxazole, or isoxazole.

[0028] In some embodiments, the CMP composition does not include an oxidizing agent, hi some embodiments, the composition does not include a reducing agent.

[0029] Methods and Compositions In another aspect of the present disclosure, the present disclosure provides a method for CMP of an object having at least one surface.The method includes, for example, contacting the surface with a polishing pad; delivering a CMP composition according to the present disclosure to the surface; and polishing the surface with the CMP composition.In some embodiments, the surface includes HfO2 or SiO2.

[0030] Examples of polished objects may include, for example, silicon nitride, silicon oxide, amorphous silicon (a-Si), or other compounds such as polysilicon.

[0031] In this regard, examples of polishing objects containing silicon oxide include tetraethyl orthosilicate (TEOS)-based silicon oxide films formed by using tetraethyl orthosilicate (hereinafter simply referred to as "TEOS") as a precursor, high discharge pressure (HDP) films, undoped silicate glass (USG) films, phosphosilicate glass (PSG) films, borophosphosilicate glass (BPSG) films, and rapid thermal oxide (RTO) films.

[0032] In another aspect of the present disclosure, there is provided herein a method of selectively increasing the removal rate of HfO2 from a surface comprising HfO2 and SiO2, comprising contacting the surface with a slurry comprising first colloidal silica particles and second colloidal silica particles, wherein the first colloidal silica particles are not surface modified and the second colloidal silica particles are surface modified and negatively charged, and the pH of the composition is 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, or 6.2 or less (e.g., 3.2 or less).

[0033] Another embodiment of the present disclosure provides herein a method for selectively removing HfO2 or SiO2 from a surface comprising HfO2 and SiO2, the method comprising contacting the surface with a slurry comprising first colloidal silica particles and second colloidal silica particles, the first colloidal silica particles being unmodified and the second colloidal silica particles being surface modified and negatively charged, the pH of the composition being 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, or 6.2 or less (e.g., 3.2 or less), and adjusting the weight ratio of the first colloidal silica particles and the second colloidal silica particles to selectively remove HfO2 and / or SiO2. In some embodiments, the slurry is a CMP composition according to the present disclosure.

[0034] In some embodiments, the removal rates of HfO2 and SiO2 are 10:1 or more. For example, the removal rate ratio (HfO2:SiO2) can be 10:1, 15:1, 20:1, 25:1, 30:1 or more. In other embodiments, the removal rates of SiO2 and HfO2 are 10:1 or more. For example, the removal rate ratio (SiO2:HfO2) can be 10:1, 15:1, 20:1, 25:1, 30:1 or more.

[0035] In another aspect of the present disclosure, a system for chemical mechanical polishing (CMP) is provided herein. The system includes a substrate comprising HfO2 and / or SiO2, a polishing pad, and at least one surface having a CMP composition according to the present disclosure.

[0036] In some embodiments, the removal rate of HfO2 is 1000 Å / min or more, e.g., 1000, 1200, 1300, 1400, 1500, 2000, 2500, 3000, 3500, 4000, or more.

[0037] In yet another aspect of the present disclosure, there is provided herein a substrate comprising at least one surface having HfO2 and / or SiO2, wherein the substrate is in contact with a chemical mechanical polishing (CMP) composition according to the present disclosure.

[0038] In some embodiments, the method and composition are suitable for polishing surfaces with HfO2 and / or SiO2. Apparatus or conditions commonly used for CMP are applied and modified according to specific needs. Appropriate apparatus and / or conditions for carrying out the method are within the knowledge of those skilled in the art.

[0039] It should be noted that, as used in this specification and the appended claims, nouns include plural referents unless the context clearly dictates otherwise. Still further, the claims may be drafted to exclude optional elements. Such drafting is intended to serve as a predicate for the use of exclusive language, such as "solely," "only," or the like, in connection with the recitation of claim elements or a negative limitation.

[0040] The term "about" will be understood by those skilled in the art and will vary to some extent depending on the context in which it is used. If there is a use of the term that is not clear to those skilled in the art given the context in which it is used, "about" will mean plus or minus 10% or less of the specific term. In this specification, a specific range is indicated with a numerical value preceded by the term "about". In this specification, the term "about" is used to provide documentary support for the exact number preceded by the term, or a number that is close or approximate to the numerical value preceded by the term. When determining whether a number is close or approximate to a specifically stated number, the unstated number that is close or approximate may be a number that provides the substantial equivalent value of the specifically stated number in the context in which it is stated.

[0041] Where a range of values ​​is provided, it is understood that, to the tenth of the unit of the lower limit, each intermediate value between the upper and lower limits of that range, as well as any other specified or intermediate value in that stated range, is included within the scope of the invention, unless the context clearly indicates otherwise. The upper and lower limits of these smaller ranges may be independently included in the smaller ranges and are encompassed within the scope of the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included within the scope of the invention.

[0042] The present disclosure is not limited to the particular embodiments described, as such may, of course, vary. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0043] As will be apparent to one of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has different components and features which may be readily separated or combined with the features of any of the other several embodiments without departing from the scope or spirit of the invention. Any described method can be carried out in the order of items described or in other order which is logically possible.

[0044] All publications and patents mentioned herein are incorporated by reference herein as if each individual publication or patent was specifically and individually indicated to be incorporated by reference, and are incorporated by reference herein to disclose and describe the methods and / or materials in connection with which the publications are described. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.

[0045] The following examples are provided for the purpose of illustrating various embodiments of the present disclosure, but are not intended to limit the disclosure in any way. Those skilled in the art will readily recognize that the present disclosure is well adapted to carry out the stated objects, goals and advantages, as well as those inherent therein. The examples of the present invention, together with the methods described herein, are intended to represent and illustrate embodiments, and are not intended to limit the scope of the present disclosure. Modifications and other uses that are encompassed within the spirit of the disclosure, as defined by the scope of the claims, will occur to those skilled in the art. EXAMPLES

[0046] Example 1: Effect of the ratio P2:P1 at pH 3.2 A slurry containing 5 wt% colloidal silica from P1 and P2 ("P2": average primary particle size 32 nm, average secondary particle size: 70 nm, on the surface where sulfonic acid is immobilized; "P1" unmodified colloidal silica particles: average primary particle size 32 nm, average secondary particle size: 70 nm), 0.0008 wt% Kordex MLX, 0.26 wt% acetic acid, and 74.4 wt% DI water was prepared and used to polish the membrane surface containing HfO2 and SiO2 using a benchtop polisher. The results are shown in Table 1. [Table 1]

[0047] At pH 3.2, the HfO2:SiO2 selectivity is between 14:1 and 0.6:1.

[0048] Comparative Example 1: Effect of the ratio P2:P1 at pH 8.7 Slurries with the same content as Slurries A1 to A5, but formulated at a pH of 8.7, were used to polish the film surface containing HfO2 and SiO2 using a benchtop polisher. The results are shown in Table 2. [Table 2]

[0049] At pH 8.7, the HfO2:SiO2 selectivity is within a very small range of 0.9:1 to 1:1, regardless of the ratio of P2:P1. Thus, the formulation is non-selective at pH 8.7.

[0050] From the results in Tables 1 and 2, at pH 3.2, the HfO2:SiO2 selectivity is significantly improved from 14:1 to 0.6:1 compared to the formulation at pH 8.7, which provides tunable selectivity for polishing HfO2 / SiO2 surfaces.

Claims

1. A chemical mechanical polishing (CMP) composition comprising first colloidal silica particles and second colloidal silica particles, said first colloidal silica particles being unmodified and said second colloidal silica particles being surface modified and negatively charged, said CMP composition having a pH of 3.2 or less, The chemical mechanical polishing (CMP) composition is used to selectively increase the removal rate of HfO2 when polishing a surface containing HfO2 and SiO2; A chemical mechanical polishing (CMP) composition, wherein the ratio (P1 / P2) of the weight (P1) of the first colloidal silica particles to the weight (P2) of the second colloidal silica particles is 3 or less.

2. 10. The chemical mechanical polishing (CMP) composition of claim 1, wherein the first colloidal silica particles and the second colloidal silica particles have the same primary particle size and the same secondary particle size.

3. 2. The chemical mechanical polishing (CMP) composition of claim 1, wherein the first and second colloidal silica particles have a primary particle size of 10-90 nm and the first and second colloidal silica particles have a secondary particle size of 20-220 nm.

4. 2. The chemical mechanical polishing (CMP) composition of claim 1, wherein a weight ratio of the first colloidal silica particles to the second colloidal silica particles is from 2:0.01 to 1:

1.

5. 10. The chemical mechanical polishing (CMP) composition of claim 1, wherein a weight ratio of the first colloidal silica particles to the second colloidal silica particles is from 1:1 to 2:0.

01.

6. 2. The chemical mechanical polishing (CMP) composition of claim 1, wherein the composition consists of the first colloidal silica particles, the second colloidal silica particles, water, a pH adjuster, and optionally one or more of a preservative, a biocide, a polymer, and a surfactant.

7. 10. The chemical mechanical polishing (CMP) composition of claim 1, wherein the first colloidal silica particles are present in an amount of from greater than 0% to 5% by weight.

8. 2. The chemical mechanical polishing (CMP) composition of claim 1, wherein the first colloidal silica particles have a zeta potential of -5 mV at pH 3.2 and the second colloidal silica particles have a zeta potential of -30 mV or more negative at pH 3.

2.

9. HfO ２ and SiO ２ From the surface containing HfO ２ 1. A method for selectively increasing the removal rate of contacting the surface with a slurry comprising first colloidal silica particles and second colloidal silica particles; the first colloidal silica particles are not surface-modified, the second colloidal silica particles are surface-modified and negatively charged, and the pH of the slurry is 3.2 or less; The method, wherein the ratio (P1 / P2) of the weight of the first colloidal silica particles (P1) to the weight of the second colloidal silica particles (P2) is 3 or less.

10. HfO ２ and SiO ２ The method of claim 9 , wherein the removal rate of is 10:1 or greater.

11. HfO ２ 10. The method of claim 9, wherein the removal rate of is 1000 Å / min or greater.

12. 10. The method of claim 9, wherein the first colloidal silica particles are present in an amount of from greater than 0% to 5% by weight.

13. 10. The method of claim 9, wherein the second colloidal silica particles are present in an amount of from greater than 0% to 5% by weight.

14. 10. The method of claim 9, wherein the slurry comprises the first colloidal silica particles, the second colloidal silica particles, water, a pH adjuster, and optionally one or more of a preservative, a biocide, a polymer, and a surfactant.

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