Polishing liquid and polishing method

Abstract

Provided is a polishing liquid containing abrasive grains and an acid component, wherein the acid component contains a compound (excluding sulfuric acid and salts thereof) having at least one type of molecule selected from the group consisting of sulfo groups and sulfonic acid groups, and has a pH of more than 4.5. Also provided is a polishing method comprising a step for polishing a surface using the polishing liquid.

Description

Polishing liquid and polishing method

[0001] The present disclosure relates to a polishing liquid, a polishing method, and the like.

[0002] In recent years, processing techniques for achieving higher density and finer features have become increasingly important in the manufacturing process of semiconductor devices. One such processing technique, chemical mechanical polishing (CMP), has become essential for forming shallow trench isolation (hereinafter referred to as "STI"), planarizing pre-metal insulating materials or interlayer insulating materials, forming plugs or buried metal wiring, and the like in the manufacturing process of semiconductor devices.

[0003] The most commonly used polishing liquids include, for example, silica-based polishing liquids containing silica (silicon oxide) particles such as fumed silica and colloidal silica as abrasive grains. Silica-based polishing liquids are characterized by their high versatility, and by appropriately selecting the abrasive grain content, pH, additives, etc., they can polish a wide variety of materials, both insulating and conductive.

[0004] On the other hand, there is also growing demand for polishing solutions containing cerium compound particles as abrasive grains, primarily for polishing insulating materials such as silicon oxide. For example, a cerium oxide-based polishing solution containing cerium oxide particles as abrasive grains can polish silicon oxide at a higher speed than a silica-based polishing solution, even with a lower abrasive grain content (see, for example, Patent Documents 1 and 2 listed below).

[0005] In recent years, in the manufacturing process of semiconductor devices, there has been a demand for further miniaturization of wiring, and polishing scratches that occur during polishing have become a problem. That is, even if minute polishing scratches occur when polishing is performed using a conventional cerium oxide-based polishing solution, this was not a problem as long as the size of the polishing scratches was smaller than the conventional wiring width. However, when attempting to achieve further miniaturization of wiring, even minute polishing scratches become a problem.

[0006] To address this issue, polishing solutions using cerium hydroxide particles have been investigated (see, for example, Patent Documents 3 to 5 below). Methods for producing cerium hydroxide particles have also been investigated (see, for example, Patent Documents 6 and 7 below).

[0007] Japanese Patent Application Laid-Open No. 10-106994 Japanese Patent Application Laid-Open No. 08-022970 International Publication No. 2002 / 067309 International Publication No. 2012 / 070541 International Publication No. 2012 / 070542 Japanese Patent Application Laid-Open No. 2006-249129 International Publication No. 2012 / 070544

[0008] In recent years, miniaturization of semiconductor devices has been accelerating, leading to shrinking wiring widths and thinner films. Accordingly, in CMP processes for forming STIs, etc., it is necessary to polish insulating materials while suppressing over-polishing of stoppers placed on convex portions of substrates having a concave-convex pattern. From this perspective, polishing solutions are required to achieve excellent polishing selectivity for insulating materials relative to stopper materials (polishing rate ratio: polishing rate of insulating material / polishing rate of stopper material), e.g., excellent polishing selectivity for silicon oxide relative to silicon nitride (polishing rate ratio: polishing rate of silicon oxide / polishing rate of silicon nitride).

[0009] An object of one aspect of the present disclosure is to provide a polishing liquid that can achieve excellent polishing selectivity for silicon oxide relative to silicon nitride. Another object of the present disclosure is to provide a polishing method using the polishing liquid.

[0010] One aspect of the present disclosure includes the following items [1] to

[11] . [1] A polishing liquid containing abrasive grains and an acid component, wherein the acid component contains a compound having at least one selected from the group consisting of a sulfo group and a sulfonate group (excluding sulfuric acid and its salts), and wherein the pH is greater than 4.5. [2] The polishing liquid according to item [1], wherein the abrasive grains contain cerium hydroxide. [3] The polishing liquid according to item [1] or [2], wherein the acid component contains an aromatic compound having at least one selected from the group consisting of a sulfo group and a sulfonate group. [4] The polishing liquid according to any one of items [1] to [3], wherein the acid component contains a compound having no amino group. [5] The polishing liquid according to any one of items [1] to [4], wherein the acid component contains an aminosulfonic acid compound. [6] The polishing liquid according to any one of items [1] to [5], wherein the acid component contains at least one selected from the group consisting of sulfanilic acid and salts thereof. [7] The polishing liquid according to any one of [1] to [6], wherein the content of the acid component is more than 0.2 mass % based on the total mass of the polishing liquid. [8] The polishing liquid according to any one of [1] to [7], further containing a nonionic polymer. [9] The polishing liquid according to [8], wherein the nonionic polymer comprises a glycerin-based polymer.

[10] The polishing liquid according to any one of [1] to [9], further containing a base component.

[11] The polishing liquid according to any one of [1] to

[10] , which is used for polishing a surface to be polished containing silicon oxide and silicon nitride.

[12] A polishing method comprising the step of polishing a surface to be polished using the polishing liquid according to any one of [1] to

[11] .

[13] The polishing method according to

[12] , wherein the surface to be polished contains silicon oxide and silicon nitride.

[14] A method for manufacturing a component, comprising the step of obtaining a component using a polished member polished by the polishing method according to

[12] or

[13] .

[0011] According to one aspect of the present disclosure, it is possible to provide a polishing liquid that can achieve excellent polishing selectivity for silicon oxide relative to silicon nitride. Also, according to another aspect of the present disclosure, it is possible to provide a polishing method using the polishing liquid.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail.

[0013] <Definitions> In this specification, the term "polishing liquid" is defined as a composition that comes into contact with the surface to be polished during polishing. The term "polishing liquid" itself does not limit the components contained in the polishing liquid. As will be described later, the polishing liquid according to this embodiment may contain abrasive grains. Abrasive grains are also called "abrasive particles," but are referred to as "abrasive grains" in this specification. Abrasive grains are generally solid particles, and during polishing, the object to be removed is thought to be removed by the mechanical action of the abrasive grains and the chemical action of the abrasive grains (mainly the surface of the abrasive grains), but the polishing mechanism is not limited. The term "polishing rate" refers to the rate at which material is removed per unit time (removal rate = removal rate).

[0014] Numerical ranges indicated using "to" indicate a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. A numerical range "A or greater" means a range exceeding A and A. A numerical range "A or less" means a range less than A and A. In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination with two or more types. When multiple substances corresponding to each component are present in the composition, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. "A or B" may contain either A or B, or both. The term "film" encompasses structures that are formed over the entire surface as well as structures that are formed only partially when observed in a plan view. The term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended effect of the process is achieved.

[0015] <Polishing Liquid> The polishing liquid according to this embodiment contains abrasive grains and an acid component, and has a pH of greater than 4.5. The acid component includes a compound having at least one selected from the group consisting of a sulfo group and a sulfonate group (excluding sulfuric acid and its salts) (hereinafter, such a compound will also be referred to as "acid component A").

[0016] The polishing liquid according to this embodiment can be used as a CMP polishing liquid. The polishing liquid according to this embodiment can be used to polish a polished surface (exposed surface) containing silicon oxide and silicon nitride, and can be used to polish a polished surface containing silicon oxide and silicon nitride to selectively remove silicon oxide relative to silicon nitride. The polishing liquid according to this embodiment can be used to polish a polished surface (exposed surface) containing silicon oxide and silicon carbonitride, and can also be used to polish a polished surface containing silicon oxide and silicon carbonitride to selectively remove silicon oxide relative to silicon carbonitride.

[0017] The polishing liquid according to this embodiment can selectively remove silicon oxide relative to silicon nitride, and can achieve excellent polishing selectivity for silicon oxide relative to silicon nitride (polishing rate ratio: polishing rate of silicon oxide / polishing rate of silicon nitride). The polishing liquid according to this embodiment can achieve a polishing rate ratio of silicon oxide to silicon nitride of 2.5 or more.

[0018] The reason why the above-mentioned effect is exhibited is not entirely clear, but the inventors speculate as follows. That is, when the polishing liquid has a pH of more than 4.5, by containing a compound having at least one selected from the group consisting of a sulfo group and a sulfonate group (excluding sulfuric acid and its salts) as an acid component, the sulfo group and sulfonate group of the compound are selectively adsorbed to silicon nitride. This significantly suppresses polishing of silicon nitride without suppressing polishing of silicon oxide. For the above reasons, the polishing liquid according to this embodiment can achieve excellent polishing selectivity for silicon oxide relative to silicon nitride. However, the reason why the effect is exhibited is not limited to the above.

[0019] The polishing rate ratio of silicon oxide to silicon nitride may be 20 or more, 30 or more, 40 or more, 50 or more, 80 or more, 100 or more, 200 or more, 300 or more, 400 or more, or 500 or more. The polishing rate ratio of silicon oxide to silicon nitride may be 5000 or less, 4500 or less, 4000 or less, 3500 or less, or 3000 or less.

[0020] According to the polishing liquid of this embodiment, for example, in the evaluation method of the examples described later, a silicon oxide polishing rate of 10 Å / min or more can be obtained, and the silicon oxide polishing rate may be 100 Å / min or more, 1000 Å / min or more, 1400 Å / min or more, 1600 Å / min or more, 1800 Å / min or more, 1900 Å / min or more, 2000 Å / min or more, 2100 Å / min or more, 2200 Å / min or more, 2300 Å / min or more, or 2400 Å / min or more.

[0021] With the polishing liquid according to this embodiment, for example, in the evaluation method of the examples described later, a silicon nitride polishing rate of 600 Å / min or less can be obtained, and the silicon nitride polishing rate may be 550 Å / min or less, 500 Å / min or less, 450 Å / min or less, 400 Å / min or less, 350 Å / min or less, 300 Å / min or less, 250 Å / min or less, 200 Å / min or less, 150 Å / min or less, 100 Å / min or less, 50 Å / min or less, 30 Å / min or less, or 10 Å / min or less.

[0022] (Abrasive grains) Examples of materials constituting the abrasive grains include abrasive grains containing hydroxides of tetravalent metal elements such as cerium, inorganic substances such as silica, alumina, ceria (cerium oxide), titania, zirconia, germania, and silicon carbide, organic substances such as polystyrene, polyacrylic acid, and polyvinyl chloride, and modified substances thereof. "Hydroxides of tetravalent metal elements" refers to abrasive grains containing hydroxides of tetravalent metal ions (M ４＋ ) and at least one hydroxide ion (OH － The hydroxide of a tetravalent metal element is a compound containing an anion other than hydroxide ion (for example, nitrate ion NO ３ － and sulfate ions SO ４ ２－For example, a hydroxide of a tetravalent metal element may contain an anion (e.g., nitrate ion NO) bonded to the tetravalent metal element. ３ － and sulfate ions SO ４ ２－ The abrasive grains may contain water of hydration. As the abrasive grains containing a hydroxide of a tetravalent metal element, composite particles containing a hydroxide of a tetravalent metal element and silica may also be used.

[0023] Abrasive grains containing hydroxides of tetravalent metal elements have higher reactivity with silicon oxide, an insulating material, and can polish silicon oxide at a high polishing rate compared to abrasive grains made of silica, ceria, etc. Furthermore, abrasive grains containing hydroxides of tetravalent metal elements tend to prevent scratches on the polished surface.

[0024] The hydroxide of a tetravalent metal element may comprise at least one selected from the group consisting of hydroxides of rare earth metal elements and hydroxides of zirconium, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride, or may comprise a hydroxide of a rare earth metal element. Examples of rare earth metal elements that can assume a tetravalent state include lanthanides such as cerium, praseodymium, and terbium. Among these, from the viewpoint of easily improving the polishing rate of insulating materials (such as silicon oxide), lanthanides or cerium may be used. In other words, the abrasive grains may comprise cerium hydroxide (a compound having a hydroxy group bonded to a cerium atom) as the hydroxide of a tetravalent metal element. A hydroxide of a rare earth metal element and a hydroxide of zirconium may be used in combination, or two or more hydroxides of rare earth metal elements may be selected and used.

[0025] The abrasive grains may contain cerium-based particles (particles containing a cerium compound) to facilitate excellent polishing selectivity of silicon oxide over silicon nitride. Examples of cerium compounds (compounds containing cerium) in the cerium-based particles include cerium hydroxide, cerium oxide, ammonium cerium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate. The cerium compound may contain tetravalent cerium or trivalent cerium. The cerium-based particles may have water of hydration. To facilitate excellent polishing selectivity of silicon oxide over silicon nitride, the cerium-based particles may contain at least one selected from the group consisting of cerium hydroxide and cerium oxide, or may contain cerium hydroxide, or may contain at least one selected from the group consisting of cerium hydroxide particles (particles containing cerium hydroxide) and cerium oxide particles (particles containing cerium oxide), or may contain cerium hydroxide particles.

[0026] In abrasive grains containing a hydroxide of a tetravalent metal element, the content of the hydroxide of the tetravalent metal element may be 50% by mass or more, more than 50% by mass, 55% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, or 75% by mass or more based on the total weight of the abrasive grains (total weight of the abrasive grains contained in the polishing liquid). From the viewpoint of easy preparation of the polishing liquid and further excellent polishing properties, the abrasive grains may be substantially composed of a hydroxide of a tetravalent metal element (substantially 100% by mass of the abrasive grains are particles of the hydroxide of a tetravalent metal element). The content of cerium hydroxide in the abrasive grains may be within the above-mentioned range.

[0027] The average particle size of the abrasive grains may be 0.1 nm or more, 0.5 nm or more, 1 nm or more, 2 nm or more, 3 nm or more, 5 nm or more, 10 nm or more, or 12 nm or more, from the viewpoint of easily improving the polishing rate of insulating materials (silicon oxide, etc.). The average particle size of the abrasive grains may be 100 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 12 nm or less, from the viewpoint of easily suppressing scratches on the polished surface. From these viewpoints, the average particle size of the abrasive grains may be 0.1 to 100 nm.

[0028] The "average particle size" of the abrasive grains refers to the average secondary particle size of the abrasive grains in the polishing liquid. The average particle size of the abrasive grains can be measured using a light diffraction / scattering particle size distribution analyzer (for example, a DelsaMax PRO product manufactured by Beckman Coulter, Inc.). Specifically, the measurement method using a DelsaMax PRO product manufactured by Beckman Coulter, Inc. involves, for example, pouring approximately 0.5 mL (L stands for "liter"; the same applies below) of the polishing liquid into a measurement cell measuring 12.5 mm x 12.5 mm x 45 mm (height) and then placing the cell in the device. The refractive index of the measurement sample is set to 1.333, the viscosity to 0.887 mPa·s, and the measurement is performed at 25°C. The value displayed as the Unimodal Size Mean (cumulant diameter) can be used as the average particle size of the abrasive grains.

[0029] The zeta potential of the abrasive grains in the polishing liquid may be positive (greater than 0 mV) from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride. The zeta potential (ζ [mV]) can be measured using a zeta potential measuring device (for example, DelsaNano C (device name) manufactured by Beckman Coulter, Inc.). The zeta potential of the abrasive grains in the polishing liquid can be obtained, for example, by putting the polishing liquid into a concentrated cell unit (a cell for high-concentration samples) for the zeta potential measuring device and measuring it.

[0030] The content of the abrasive grains may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride. The content of the abrasive grains may be 0.001 mass% or more, 0.005 mass% or more, 0.008 mass% or more, 0.01 mass% or more, more than 0.01 mass%, 0.03 mass% or more, 0.04 mass% or more, or 0.05 mass% or more. The content of the abrasive grains may be 10 mass% or less, 5 mass% or less, 1 mass% or less, less than 1 mass%, 0.5 mass% or less, 0.3 mass% or less, 0.1 mass% or less, less than 0.1 mass%, 0.08 mass% or less, 0.07 mass% or less, 0.06 mass% or less, or 0.05 mass% or less. From these viewpoints, the content of the abrasive grains may be 0.001 to 10 mass%. From the same viewpoint, the content of cerium hydroxide may be within the above-mentioned range.

[0031] (Additives) The polishing liquid according to this embodiment contains additives. The "additives" refer to substances contained in the polishing liquid other than the abrasive grains and water.

[0032] [Acid Component A] The polishing liquid according to this embodiment contains, as an acid component, a compound (acid component A) having at least one selected from the group consisting of a sulfo group and a sulfonate group (a functional group in which the hydrogen atom of the sulfo group is substituted with a metal atom (sodium atom, potassium atom, etc.)). By using acid component A, it is possible to obtain excellent polishing selectivity for silicon oxide relative to silicon nitride while preventing aggregation of abrasive grains, etc. Acid component A does not contain sulfuric acid or its salts.

[0033] The number of sulfo groups and sulfonate groups contained in the acid component A may be 5 or less, 4 or less, 3 or less, 2 or less, or 1, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride.

[0034] The acid component A may have a functional group other than a sulfo group and a sulfonate group. The acid component A may further have, for example, at least one selected from the group consisting of an amino group, a carboxyl group, and a carboxylate group. The acid component A does not need to have an amino group, from the viewpoint of easily suppressing the polishing rate of silicon nitride.

[0035] The number of amino groups in the acid component A may be 5 or less, 4 or less, 3 or less, or 2 or less, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride.

[0036] The acid component A may contain an organic acid component (organic acid or organic acid derivative) or an aromatic compound, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride. When the acid component A is an aromatic compound, the aromatic ring is adsorbed to silicon nitride, making it easier to obtain excellent polishing selectivity of silicon oxide relative to silicon nitride. The aromatic ring may be a monocyclic ring or a polycyclic ring. The aromatic ring may be at least one selected from the group consisting of a benzene ring, a naphthalene ring, a pyridine ring, and an isoquinoline ring.

[0037] When the acid component A contains an organic acid component, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride, the number of carbon atoms in the organic acid component may be 2 or more, 3 or more, 4 or more, or 5 or more. The number of carbon atoms in the organic acid component may be 12 or less, 11 or less, 10 or less, or 9 or less.

[0038] Examples of the aromatic compound include aromatic aminosulfonic acids such as aminobenzenesulfonic acid (sulfanilic acid (also known as 4-aminobenzenesulfonic acid), metanilic acid (also known as 3-aminobenzenesulfonic acid), orthanilic acid (also known as 2-aminobenzenesulfonic acid), 2,4-diaminobenzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, aminonaphthalenesulfonic acid, and 1,3-phenylenediamine-4-sulfonic acid; and aromatic sulfonic acids such as benzenesulfonic acid, dimethylbenzenesulfonic acid, pyridinesulfonic acid, and isoquinoline-5-sulfonic acid. Acid component A may contain an aromatic compound having at least one selected from the group consisting of a sulfo group and a sulfonate group, or may contain an aromatic compound having an amino group and at least one selected from the group consisting of a sulfo group and a sulfonate group (aromatic aminosulfonic acid and a salt thereof).

[0039] From the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride, the acid component A may contain at least one aminosulfonic acid compound selected from the group consisting of aminosulfonic acids and aminosulfonate salts. The aminosulfonic acid compound has an amino group as the cation moiety and a sulfonic acid group or sulfonate salt group as the anion moiety. Examples of the aminosulfonic acid compound include aromatic aminosulfonic acids, aliphatic aminosulfonic acids, sulfamic acids, and salts thereof.

[0040] Examples of aromatic aminosulfonic acids include aminobenzenesulfonic acid (sulfanilic acid (also known as 4-aminobenzenesulfonic acid), metanilic acid (also known as 3-aminobenzenesulfonic acid), orthanilic acid (also known as 2-aminobenzenesulfonic acid), 2,4-diaminobenzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, aminonaphthalenesulfonic acid, and 1,3-phenylenediamine-4-sulfonic acid.

[0041] Examples of aliphatic aminosulfonic acids include aminomethanesulfonic acid, aminoethanesulfonic acid (e.g., 1-aminoethanesulfonic acid and 2-aminoethanesulfonic acid (also known as taurine)), aminopropanesulfonic acid (e.g., 1-aminopropane-2-sulfonic acid and 2-aminopropane-1-sulfonic acid), and the like.

[0042] From the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride, the acid component A may contain at least one selected from the group consisting of sulfanilic acid, sulfamic acid, benzenesulfonic acid, dimethylbenzenesulfonic acid, pyridinesulfonic acid, isoquinoline-5-sulfonic acid, and salts thereof.

[0043] The content of the acid component A may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The content of the acid component A may be 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, more than 0.05 mass%, 0.08 mass% or more, 0.1 mass% or more, more than 0.1 mass%, 0.12 mass% or more, 0.14 mass% or more, 0.15 mass% or more, or 0.16 mass% or more. The content of the acid component A may be 10 mass% or less, 5 mass% or less, 3 mass% or less, 1 mass% or less, less than 1 mass%, 0.8 mass% or less, 0.6 mass% or less, 0.5 mass% or less, less than 0.5 mass%, 0.4 mass% or less, or 0.35 mass% or less. From these viewpoints, the content of the acid component A may be 0.01 to 10 mass%. The content of acid component A may be 0.2% by mass or more, more than 0.2% by mass, 0.22% by mass or more, 0.24% by mass or more, 0.26% by mass or more, 0.28% by mass or more, 0.3% by mass or more, or 0.32% by mass or more.

[0044] The content of acid component A in the acid component contained in the polishing liquid (based on the total mass of the acid components), the content of aromatic aminosulfonic acid in the acid component contained in the polishing liquid (based on the total mass of the acid components), and / or the content of aromatic aminosulfonic acid in acid component A (based on the total mass of the acid component A) may be 80 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, or 99 mass% or more, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The acid component contained in the polishing liquid may be essentially composed of acid component A (substantially 100 mass% of the acid component contained in the polishing liquid is acid component A). The acid component contained in the polishing liquid may be essentially composed of aromatic aminosulfonic acid (substantially 100 mass% of the acid component contained in the polishing liquid is aromatic aminosulfonic acid). The acid component A may be essentially composed of aromatic aminosulfonic acid (substantially 100 mass% of the acid component A is aromatic aminosulfonic acid).

[0045] The mass ratio of the content of acid component A to the content of abrasive grains (content of acid component A / content of abrasive grains) may be within the following ranges, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The mass ratio may be 20 or less, 15 or less, 12 or less, 10 or less, 9 or less, 8 or less, 7.5 or less, 7 or less, or 6.5 or less. The mass ratio may be 0.1 or more, 0.5 or more, 1 or more, 1.5 or more, 2 or more, 2.2 or more, 2.4 or more, 2.6 or more, 2.8 or more, 3 or more, 3.2 or more, 3.4 or more, 3.6 or more, 3.8 or more, 4 or more, 4.2 or more, 4.4 or more, 4.6 or more, or 4.8 or more. From these viewpoints, the mass ratio may be 0.1 to 20. The mass ratio may be 5 or more, 5.2 or more, 5.4 or more, 5.6 or more, 5.8 or more, 6 or more, 6.2 or more, or 6.4 or more.

[0046] [Nonionic Polymer] The polishing liquid according to this embodiment may further contain a nonionic polymer. A "nonionic polymer" is a polymer that does not have, in its main chain or side chain, a cationic group, a group that can be ionized into a cationic group, or an anionic group, or a group that can be ionized into an anion. Examples of cationic groups include amino groups, imino groups, and cyano groups, and examples of anionic groups include carboxyl groups, phosphate groups, and sulfonic acid groups. A nonionic polymer has multiple structural units (repeating units) of the same type. The use of a nonionic polymer facilitates dispersion of abrasive grains, making it easier to obtain excellent polishing selectivity for silicon oxide relative to silicon nitride.

[0047] Examples of nonionic polymers include glycerin-based polymers, polyoxyalkylene compounds, polyvinyl alcohol, and polyvinylpyrrolidone.

[0048] Examples of glycerin-based polymers include polyglycerin and polyglycerin derivatives, such as polyoxyalkylene polyglyceryl ethers, polyglycerin fatty acid esters, and polyglycerin alkyl ethers.

[0049] The polyoxyalkylene compound is a compound having a polyoxyalkylene chain, and examples of the polyoxyalkylene compound include polyalkylene glycols and polyoxyalkylene derivatives.

[0050] Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polybutylene glycol.

[0051] Examples of polyoxyalkylene derivatives include compounds in which a substituent has been introduced into a polyalkylene glycol, and compounds in which a polyalkylene oxide has been added to an organic compound. Examples of the substituent include an alkyl ether group, an alkylphenyl ether group, a phenyl ether group, a styrenated phenyl ether group, a fatty acid ester group, and a glycol ester group. Examples of polyoxyalkylene derivatives include aromatic polyoxyalkylene compounds, polyoxyalkylene alkyl ethers, polyoxyalkylene sorbitan fatty acid esters, and polyoxyalkylene fatty acid esters.

[0052] An aromatic polyoxyalkylene compound is a compound in which a substituent having an aromatic ring is introduced into a polyoxyalkylene chain. The aromatic ring may or may not be directly bonded to the polyoxyalkylene chain. The aromatic ring may be monocyclic or polycyclic. The aromatic polyoxyalkylene compound may have a structure in which multiple polyoxyalkylene chains are bonded via a substituent having an aromatic ring. From the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride, the polyoxyalkylene chain may be at least one selected from the group consisting of a polyoxyethylene chain, a polyoxypropylene chain, and a polyoxyethylene-polyoxypropylene chain.

[0053] When aromatic ring is located at the end of aromatic polyoxyalkylene compound, the substituent having aromatic ring can be aryl group etc. The aryl group can be phenyl group, benzyl group, tolyl group, xylyl group etc., monocyclic aromatic group; naphthyl group etc., polycyclic aromatic group, these aromatic group can further have a substituent. The substituent that can be introduced into aromatic group can be alkyl group, vinyl group, allyl group, alkenyl group, alkynyl group, styrene group etc., and can be alkyl group or styrene group from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide to silicon nitride.

[0054] When the aromatic ring is located in the main chain of the aromatic polyoxyalkylene compound, examples of the substituent having the aromatic ring include an arylene group. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group, a tolylene group, and a xylylene group; and polycyclic aromatic groups such as a naphthylene group, and these aromatic groups may further have a substituent. Examples of the substituent introduced into the aromatic group include an alkyl group, a vinyl group, an allyl group, an alkenyl group, an alkynyl group, and a styrene group.

[0055] From the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride, the aromatic polyoxyalkylene compound may contain at least one compound selected from the group consisting of compounds represented by the following general formula (I) and compounds represented by the following general formula (II): １１ -O-(R １２ -O) ｍ -H...(I) [In formula (I), R １１ represents an aryl group which may have a substituent, R １２ represents an alkylene group having 1 to 5 carbon atoms which may have a substituent, and m represents an integer of 10 or more.] H—(O—R ２３ ) ｎ１ -O-R ２１ -R ２５ -R ２２ -O-(R ２４ -O) ｎ２ -H...(II) [In formula (II), R ２１ and R ２２ each independently represents an arylene group which may have a substituent, R２３ , R ２４ and R ２５ each independently represents an alkylene group having 1 to 5 carbon atoms which may have a substituent, and n1 and n2 each independently represent an integer of 15 or greater.

[0056] From the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride, formula (I) may satisfy at least one of the following conditions: １１ R may be any of the aryl groups exemplified above as substituents having an aromatic ring, a phenyl group having a styrene group or an alkyl group introduced as a substituent, or a phenyl group having multiple (for example, two) styrene groups introduced as substituents. １２ may be an alkylene group having 1 to 3 carbon atoms or an ethylene group. m may be 15 or more, or 30 or more. m may be 20,000 or less, 10,000 or less, 5,000 or less, or 1,000 or less.

[0057] Examples of the aromatic polyoxyalkylene compound represented by formula (I) include polyoxyalkylene phenyl ether, polyoxyalkylene alkyl phenyl ether, polyoxyalkylene styrenated phenyl ether, polyoxyalkylene distyrenated phenyl ether, polyoxyalkylene cumyl phenyl ether, polyoxyalkylene benzyl ether, etc. Specific examples of the aromatic polyoxyalkylene compound represented by formula (I) include polyoxyethylene alkyl phenyl ether, polyoxyethylene nonylpropenyl phenyl ether, polyoxyethylene phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxypropylene phenyl ether, polyoxyethylene cumyl phenyl ether, polyoxyethylene benzyl ether, etc.

[0058] Examples of the aromatic polyoxyalkylene compound represented by formula (II) include polyoxyalkylene bisphenol ether, etc. Specific examples of the aromatic polyoxyalkylene compound represented by formula (II) include 2,2-bis(4-polyoxyethyleneoxyphenyl)propane, etc.

[0059] The nonionic polymer may contain at least one selected from the group consisting of a glycerin-based polymer and a polyoxyalkylene compound, or may contain a glycerin-based polymer and a polyoxyalkylene compound, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide over silicon nitride. The polyoxyalkylene compound may contain an aromatic polyoxyalkylene compound, or may contain at least one selected from the group consisting of polyoxyalkylene styrenated phenyl ether and polyoxyalkylene distyrenated phenyl ether, or may contain at least one selected from the group consisting of polyoxyethylene styrenated phenyl ether and polyoxyethylene distyrenated phenyl ether, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide over silicon nitride.

[0060] The polishing liquid according to this embodiment may contain a nonionic polymer having the following weight-average molecular weight, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The weight-average molecular weight of the nonionic polymer may be 100 or more, 200 or more, 300 or more, 500 or more, 600 or more, 700 or more, or 750 or more. The weight-average molecular weight of the nonionic polymer may be 100,000 or less, 50,000 or less, 10,000 or less, 5,000 or less, 3,000 or less, 1,000 or less, 800 or less, or 750 or less. From these viewpoints, the weight-average molecular weight of the nonionic polymer may be 100 to 100,000.

[0061] The weight-average molecular weight of the nonionic polymer can be measured, for example, by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene under the following conditions: Instrument used: Hitachi L-6000 model [manufactured by Hitachi, Ltd.] Column: Gelpack GL-R420 + Gelpack GL-R430 + Gelpack GL-R440 [trade names manufactured by Hitachi High-Tech Corporation, a total of three columns] Eluent: tetrahydrofuran Measurement temperature: 40°C Flow rate: 1.75 mL / min Detector: L-3300RI [manufactured by Hitachi, Ltd.]

[0062] The content of the nonionic polymer may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride. The content of the nonionic polymer may be 0.001% by mass or more, 0.005% by mass or more, 0.008% by mass or more, 0.01% by mass or more, 0.03% by mass or more, 0.05% by mass or more, 0.08% by mass or more, 0.1% by mass or more, more than 0.1% by mass, 0.3% by mass or more, 0.4% by mass or more, or 0.5% by mass or more. The content of the nonionic polymer may be 10% by mass or less, 5% by mass or less, 1% by mass or less, less than 1% by mass, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, 0.55% by mass or less, or 0.5% by mass or less. From these viewpoints, the content of the nonionic polymer may be 0.001 to 10% by mass.

[0063] The content of the glycerin-based polymer may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily achieving excellent polishing selectivity for silicon oxide relative to silicon nitride. The content of the glycerin-based polymer may be 0.001 mass% or more, 0.005 mass% or more, 0.008 mass% or more, 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.08 mass% or more, 0.1 mass% or more, more than 0.1 mass%, 0.3 mass% or more, 0.4 mass% or more, or 0.5 mass% or more. The content of the glycerin-based polymer may be 10 mass% or less, 5 mass% or less, 1 mass% or less, less than 1 mass%, 0.8 mass% or less, 0.7 mass% or less, 0.6 mass% or less, or 0.5 mass% or less. From these viewpoints, the content of the glycerin-based polymer may be 0.001 to 10 mass%.

[0064] When the nonionic polymer contains a glycerin-based polymer, the content of the glycerin-based polymer in the nonionic polymer may be 50 mass% or more, more than 50 mass%, 80 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, or 99 mass% or more, based on the total mass of the nonionic polymer, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The nonionic polymer may be essentially composed of a glycerin-based polymer (substantially 100 mass% of the nonionic polymer is a glycerin-based polymer).

[0065] The content of the nonionic polymer per 100 parts by mass of the abrasive grains may be within the following ranges, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride. The content of the nonionic polymer per 100 parts by mass of the abrasive grains may be 2000 parts by mass or less, 1500 parts by mass or less, 1200 parts by mass or less, 1100 parts by mass or less, or 1000 parts by mass or less. The content of the nonionic polymer per 100 parts by mass of the abrasive grains may be 1 part by mass or more, 10 parts by mass or more, 100 parts by mass or more, 500 parts by mass or more, 700 parts by mass or more, 900 parts by mass or more, or 1000 parts by mass or more. From these viewpoints, the content of the nonionic polymer per 100 parts by mass of the abrasive grains may be 1 to 2000 parts by mass.

[0066] The content of the nonionic polymer per 100 parts by mass of the acid component A may be in the following range, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The content of the nonionic polymer per 100 parts by mass of the acid component A may be 2000 parts by mass or less, 1500 parts by mass or less, 1000 parts by mass or less, 900 parts by mass or less, 800 parts by mass or less, or 700 parts by mass or less. The content of the nonionic polymer per 100 parts by mass of the acid component A may be 1 part by mass or more, 10 parts by mass or more, 50 parts by mass or more, 100 parts by mass or more, 120 parts by mass or more, 140 parts by mass or more, or 150 parts by mass or more. From these viewpoints, the content of the nonionic polymer per 100 parts by mass of the acid component A may be 1 to 2000 parts by mass.

[0067] [Base Component] The polishing liquid according to this embodiment may further contain a base component. The addition of a base component to a polishing liquid containing an acid component A tends to provide a pH buffering effect, which facilitates stabilization of the pH of the polishing liquid and thus facilitates excellent polishing selectivity for silicon oxide relative to silicon nitride. Examples of base components include compounds having an amino group (heterocyclic amines, alkylamines, etc.), ammonia, sodium hydroxide, etc. Regarding amphoteric compounds, if the isoelectric point (pI) of the compound exceeds 4.5, the compound is considered to be a base component. Examples of compounds having an isoelectric point exceeding 4.5 include glycine. The base component may include a compound having an amino group, a fatty acid amine, or a heterocyclic amine, from the viewpoint of further stabilizing the pH of the polishing liquid.

[0068] Examples of fatty acid amines include monoamines such as methylamine, ethylamine, and trishydroxymethylaminomethane; diamines such as dimethylamine and diethylamine; and triamines such as trimethylamine and triethylamine. The base component may contain either a monoamine or trishydroxymethylaminomethane, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride.

[0069] The heterocyclic amine is an amine having at least one heterocycle. Examples of the heterocyclic amine include compounds having a pyrrolidine ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, a tetrazine ring, etc. The base component may contain an imidazole compound (a compound having an imidazole ring) or may contain imidazole, from the viewpoint of easily obtaining excellent polishing selectivity of silicon oxide relative to silicon nitride.

[0070] The content of the base component may be within the following ranges based on the total mass of the polishing liquid, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The content of the base component may be 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.07 mass% or more, or 0.08 mass% or more. The content of the base component may be 3 mass% or less, 1 mass% or less, 0.8 mass% or less, 0.6 mass% or less, 0.5 mass% or less, 0.4 mass% or less, 0.3 mass% or less, or 0.2 mass% or less. From these viewpoints, the content of the base component may be 0.001 to 3 mass%.

[0071] When the polishing liquid according to this embodiment contains an acid component A and a base component, the mass ratio of the content of the base component to the content of the acid component A (base component content / acid component A content) may be 0.1 or more, 0.3 or more, 0.5 or more, 0.8 or more, 0.9 or more, 1 or more, 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, or 2 or more, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The mass ratio may be 10 or less, 8 or less, 6 or less, 5 or less, 4 or less, 3.5 or less, 3 or less, 2.9 or less, 2.8 or less, 2.7 or less, 2.6 or less, or 2.5 or less. From these viewpoints, the mass ratio may be 0.1 to 10.

[0072] [Other Additives] The polishing liquid according to this embodiment may contain any additive (excluding compounds corresponding to the above-mentioned acid component A, nonionic polymer, or base component). Examples of the optional additive include an oxidizing agent (such as hydrogen peroxide), a dispersant (such as triethylolethane), an alcohol (such as 3-methoxy-3-methyl-1-butanol), and an acid component other than acid component A (such as an acid component having a carboxy group). The polishing liquid according to this embodiment may or may not contain a cationic polymer. The content of the cationic polymer may be less than 0.0001% by mass based on the total mass of the polishing liquid.

[0073] (Water) The polishing liquid according to this embodiment may contain water. Examples of water include deionized water and ultrapure water. The content of water may be the remainder of the polishing liquid excluding the contents of other components.

[0074] (pH) The pH of the polishing liquid according to this embodiment is greater than 4.5, from the viewpoint of obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The pH of the polishing liquid may be 4.6 or greater, 4.7 or greater, 4.8 or greater, 4.9 or greater, 5 or greater, or 5.1 or greater, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The pH of the polishing liquid may be 12 or less, 11 or less, 10 or less, 9 or less, 8.8 or less, 8.6 or less, 8.4 or less, 8.2 or less, 8 or less, less than 8, 7.8 or less, 7.6 or less, 7.5 or less, less than 7.5, 7.4 or less, 7.2 or less, 7 or less, less than 7, 6.8 or less, 6.6 or less, 6.5 or less, less than 6.5, 6.4 or less, 6.2 or less, 6 or less, or less than 6, from the viewpoint of easily obtaining excellent polishing selectivity for silicon oxide relative to silicon nitride. The pH of the polishing liquid may be 5.2 or more, 5.3 or more, 5.4 or more, 5.5 or more, 5.6 or more, 5.7 or more, 5.8 or more, 5.9 or more, 6 or more, or more than 6. The pH of the polishing liquid is defined as the pH at a liquid temperature of 25°C.

[0075] The pH of the polishing solution according to this embodiment can be measured using a pH meter (for example, Model D-51 manufactured by HORIBA, Ltd.). For example, the pH meter is calibrated at three points using standard buffer solutions of phthalate pH buffer solution (pH: 4.01), neutral phosphate pH buffer solution (pH: 6.86), and borate pH buffer solution (pH: 9.18), and then the electrode of the pH meter is placed in the polishing solution and the pH value is measured after stabilization for at least three minutes. The liquid temperatures of both the standard buffer solution and the polishing solution are 25°C.

[0076] The polishing liquid according to this embodiment may be stored as a one-component polishing liquid containing at least abrasive grains containing a hydroxide of a tetravalent metal element and an acid component A, or may be stored as a multi-component (e.g., two-component) polishing liquid set in which the components of the polishing liquid described above are separated into a slurry and an additive liquid so that the polishing liquid described above is obtained by mixing a slurry (first liquid) and an additive liquid (second liquid). The slurry contains, for example, at least abrasive grains and water. The additive liquid contains, for example, at least acid component A and water. It is preferable that the base component and other additives are contained in the additive liquid of the slurry and the additive liquid. The components of the polishing liquid described above may be stored as a polishing liquid set separated into three or more liquids.

[0077] In the above-mentioned polishing liquid set, the slurry and the additive liquid are mixed immediately before or during polishing to prepare the polishing liquid. The single-component polishing liquid may be stored as a stock liquid for the polishing liquid with a reduced water content, and may be diluted with water before use during polishing. The multiple-component polishing liquid set may be stored as a stock liquid for the slurry and a stock liquid for the additive liquid with a reduced water content, and may be diluted with water before use during polishing.

[0078] The method for producing a polishing liquid according to this embodiment includes a mixing step of mixing abrasive grains with an acid component A. The mixing step may be a step of obtaining a polishing liquid by mixing the abrasive grains and the acid component A together. The mixing step may be a step of obtaining a polishing liquid by mixing the abrasive grains and the acid component A together, as well as a component other than the abrasive grains and the acid component A (for example, a nonionic polymer).

[0079] <Polishing Method> The polishing method according to this embodiment includes a polishing step of polishing a surface to be polished using the polishing liquid according to this embodiment. In the polishing step, the material to be polished on the surface to be polished is polished and removed. The surface to be polished may contain silicon oxide and silicon nitride. That is, the surface to be polished may have a polishing portion made of silicon oxide and a polishing portion made of silicon nitride. The polishing step may be a step of polishing a surface to be polished containing silicon oxide and silicon nitride using the polishing liquid according to this embodiment, thereby selectively removing the silicon oxide relative to the silicon nitride. The polishing liquid used in the polishing step may be the one-component polishing liquid described above, or may be a polishing liquid obtained by mixing the slurry and additive liquid in the polishing liquid set described above.

[0080] In the polishing process, for example, the surface to be polished of the substrate is pressed against a polishing pad (abrasive cloth) on a polishing table, the above-mentioned polishing liquid is supplied between the surface to be polished and the polishing pad, and the substrate and the polishing table are moved relative to each other to polish the surface to be polished.

[0081] Examples of the substrate to be polished include a substrate to be polished. Examples of the substrate to be polished include a substrate involved in semiconductor manufacturing (e.g., a semiconductor substrate on which an STI pattern, a gate pattern, a wiring pattern, etc. are formed) on which a material to be polished is formed. The portion to be polished of the substrate to be polished may contain silicon oxide and silicon nitride. The portion to be polished may be in the form of a film (film to be polished), and may be a silicon oxide film, a silicon nitride film, etc.

[0082] The polished portion may be a silicon carbonitride film. A silicon carbonitride film is a film in which silicon nitride is doped with carbon atoms. Whether the polished portion is a silicon carbonitride film can be confirmed by Raman spectroscopy.

[0083] In the polishing method according to this embodiment, a general polishing apparatus having a holder capable of holding a substrate having a surface to be polished and a polishing platen to which a polishing pad can be attached can be used. Each of the holder and the polishing platen may be equipped with a motor or the like capable of changing the rotation speed. For example, a polishing apparatus such as the Reflexion polishing apparatus manufactured by Applied Materials can be used.

[0084] The polishing pad can be made of a general nonwoven fabric, foam, non-foam, etc. The polishing pad can be made of a resin such as polyurethane, acrylic resin, polyester, acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly-4-methylpentene, cellulose, cellulose ester, polyamide (e.g., Nylon (trade name) and aramid), polyimide, polyimideamide, polysiloxane copolymer, oxirane compound, phenol resin, polystyrene, polycarbonate, or epoxy resin.

[0085] There are no restrictions on the polishing conditions, but the rotation speed (number of rotations) of the polishing platen is set to 200 min so that the substrate does not jump out. －１ The polishing pressure (processing load) applied to the substrate may be 100 kPa or less from the viewpoint of sufficiently suppressing the occurrence of polishing scratches. During polishing, a polishing liquid may be continuously supplied to the polishing pad by a pump or the like. There is no limit to the amount of supply, but the surface of the polishing pad may be constantly covered with the polishing liquid.

[0086] After polishing, the substrate may be thoroughly washed in running water to remove particles adhering to the substrate. For washing, other cleaning chemicals such as dilute hydrofluoric acid and aqueous ammonia may be used in addition to pure water, and a brush may be used to improve the efficiency of washing. After washing, water droplets adhering to the substrate may be removed using a spin dryer or the like, and then the substrate may be dried.

[0087] The polishing liquid and polishing method according to this embodiment may be applied not only to film-like objects to be polished, but also to various substrates made of glass, silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, sapphire, plastic, etc.

[0088] The polishing liquid and polishing method according to this embodiment can be used not only in the manufacture of semiconductor devices, but also in the manufacture of image display devices such as TFT liquid crystals and organic EL; optical components such as photomasks, lenses, prisms, optical fibers and single crystal scintillators; optical elements such as optical switching elements and optical waveguides; light-emitting elements such as solid-state lasers and blue laser LEDs; and magnetic storage devices such as magnetic disks and magnetic heads.

[0089] <Manufacturing Method, etc.> The component manufacturing method according to this embodiment includes a component fabrication step in which a component is obtained using a substrate (a member to be polished) polished by the polishing method according to this embodiment. The component according to this embodiment is a component obtained by the component manufacturing method according to this embodiment. The component according to this embodiment is not particularly limited, and may be an electronic component (e.g., a semiconductor component such as a semiconductor package), a wafer (e.g., a semiconductor wafer), or a chip (e.g., a semiconductor chip). As one aspect of the component manufacturing method according to this embodiment, an electronic component is obtained using a substrate polished by the polishing method according to this embodiment. As one aspect of the component manufacturing method according to this embodiment, a semiconductor component (e.g., a semiconductor package) is obtained using a substrate polished by the polishing method according to this embodiment. The component manufacturing method according to this embodiment may include a polishing step in which a substrate is polished by the polishing method according to this embodiment before the component fabrication step.

[0090] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a singulation step of singulating a substrate (a polished member) polished by the polishing method according to this embodiment. The singulation step may be, for example, a step of dicing a wafer (e.g., a semiconductor wafer) polished by the polishing method according to this embodiment to obtain chips (e.g., semiconductor chips). As one aspect of the component manufacturing method according to this embodiment, the electronic component manufacturing method according to this embodiment may include a step of singulating a substrate polished by the polishing method according to this embodiment to obtain electronic components (e.g., semiconductor components). As one aspect of the component manufacturing method according to this embodiment, the semiconductor component manufacturing method according to this embodiment may include a step of singulating a substrate polished by the polishing method according to this embodiment to obtain semiconductor components (e.g., semiconductor packages).

[0091] The component manufacturing method according to this embodiment may include, as one aspect of the component manufacturing process, a connection process in which a substrate (a polished member) polished by the polishing method according to this embodiment is connected (e.g., electrically connected) to another object to be connected. The object to be connected to the substrate polished by the polishing method according to this embodiment is not particularly limited and may be the substrate polished by the polishing method according to this embodiment, or may be a different object to be connected from the substrate polished by the polishing method according to this embodiment. In the connection process, the substrate and the object to be connected may be directly connected (connected in a state where the substrate and the object to be connected are in contact), or the substrate and the object to be connected may be connected via another member (such as a conductive member). The connection process may be performed before the singulation process, after the singulation process, or before or after the singulation process.

[0092] The connecting step may be a step of connecting a polished surface of a base polished by the polishing method according to this embodiment to a connected body, or a step of connecting a connecting surface of a base polished by the polishing method according to this embodiment to a connecting surface of a connected body. The connecting surface of the base may be a polished surface polished by the polishing method according to this embodiment. A connecting body including a base and a connected body can be obtained by the connecting step. In the connecting step, if the connecting surface of the base has a metal portion, the connected body may be brought into contact with the metal portion. In the connecting step, if the connecting surface of the base has a metal portion and the connecting surface of the connected body has a metal portion, the metal portions may be brought into contact with each other. The metal portion may contain copper.

[0093] The device according to this embodiment (for example, an electronic device such as a semiconductor device) includes a substrate polished by the polishing method according to this embodiment and at least one selected from the group consisting of the part according to this embodiment.

[0094] The present disclosure will be described in more detail below with reference to examples. However, the present disclosure is not limited to these examples as long as it does not deviate from the technical concept of the present disclosure. For example, the types and blending ratios of the materials in the polishing liquid may be different from those described in the examples, and the composition and structure of the object to be polished may also be different from those described in the examples.

[0095] <Preparation of abrasive grains> 350 g of Ce(NH ４ ) ２ (NO ３ A 650 mass% aqueous solution of imidazole (product name: CAN50 Liquid, manufactured by Nippon Chemical Industry Co., Ltd.) was mixed with 7,825 g of pure water to obtain a solution. Next, while stirring this solution, 750 g of an aqueous solution of imidazole (10 mass% aqueous solution, 1.47 mol / L) was added dropwise at a mixing rate of 5 mL / min to obtain a precipitate containing cerium hydroxide. The synthesis of cerium hydroxide was carried out at a temperature of 25°C and a stirring rate of 400 min. －１ The stirring was carried out using a three-blade pitch paddle with a blade length of 5 cm.

[0096] The resulting precipitate (precipitate containing cerium hydroxide) was centrifuged (4000 min －１ After stirring for 5 minutes, the mixture was subjected to solid-liquid separation by removing the liquid phase by decantation. 10 g of the particles obtained by solid-liquid separation was mixed with 990 g of water, and the particles were dispersed in water using an ultrasonic cleaner to prepare a cerium hydroxide slurry (abrasive grain content: 1.0 mass %) containing abrasive grains containing cerium hydroxide.

[0097] <Measurement of Average Particle Size> The average particle size of abrasive grains (abrasive grains containing cerium hydroxide) in a cerium hydroxide slurry was measured using Beckman Coulter, Inc., product name: N5, and was found to be 3 nm. The measurement method is as follows. First, approximately 1 mL of a measurement sample (cerium hydroxide slurry, aqueous dispersion) containing 1.0 mass % abrasive grains was placed in a 1 cm square cell, and the cell was placed inside the N5. The refractive index and viscosity of the measurement sample information for the N5 software were set to 1.333 and 0.887 mPa s, respectively, and the measurement was performed at 25°C.

[0098] <Structural analysis of abrasive grains> An appropriate amount of cerium hydroxide slurry was collected, vacuum dried to isolate the abrasive grains, and then thoroughly washed with pure water to obtain a sample. The obtained sample was measured by the FT-IR ATR method, and it was found that hydroxide ions (OH － In addition to the peak due to nitrate ions (NO ３ －In addition, when the same sample was subjected to XPS (N-XPS) measurement for nitrogen, a peak due to NH ４ ＋ No peak due to nitrate ions was observed, but a peak due to nitrate ions was observed. These results confirmed that the abrasive grains contained in the cerium hydroxide slurry contained at least some particles having nitrate ions bonded to elemental cerium. Furthermore, since at least some of the abrasive grains contained particles having hydroxide ions bonded to elemental cerium, it was confirmed that the abrasive grains contained cerium hydroxide. These results confirmed that cerium hydroxide contained hydroxide ions bonded to elemental cerium.

[0099] <Preparation of CMP Polishing Liquid> (Example 1) 100 g of an additive liquid containing 1.6 mass % of sulfanilic acid, 5 mass % of polyglycerin [nonionic polymer, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., trade name: Polyglycerin #750, weight average molecular weight: 750, average degree of polymerization: 10], 1.4 mass % of imidazole, and water (the balance) was mixed with 850 g of water and 50 g of the above-mentioned cerium hydroxide slurry to prepare a CMP polishing liquid containing 0.05 mass % of abrasive grains containing cerium hydroxide, 0.16 mass % of sulfanilic acid, 0.5 mass % of polyglycerin, and 0.14 mass % of imidazole.

[0100] Examples 2 to 15 and Comparative Examples 1 and 2 CMP polishing solutions having the compositions shown in Table 1 were prepared in the same manner as in Example 1, except that the types and contents of the acid component and base component were changed. The acid components A1 to A8 and base components B1 and B2 in the table are as follows:

[0101] [Acid components] A1: Sulfanilic acid A2: 3-pyridinesulfonic acid A3: Sulfamic acid A4: Benzene sulfonic acid A5: 2,5-dimethylbenzene sulfonic acid A6: Isoquinoline-5-sulfonic acid A7: 4-aminobenzoic acid A8: Acetic acid

[0102] [Base component] B1: Imidazole B2: Trishydroxymethylaminomethane

[0103] <Evaluation> (pH of CMP polishing solution) The pH of the CMP polishing solution was measured under the following conditions. The results are shown in Table 1. Measurement temperature: 25°C Measurement device: Model D-51 manufactured by HORIBA, Ltd. Measurement method: After three-point calibration was performed using standard buffer solutions (phthalate pH buffer solution, pH: 4.01 (25°C); neutral phosphate pH buffer solution, pH: 6.86 (25°C); borate pH buffer solution, pH: 9.18 (25°C)), the electrode was immersed in the CMP polishing solution, and the pH was measured using the above-mentioned measurement device after stabilization for 3 minutes or more.

[0104] (Abrasive Grain Particle Size) The average particle size of the abrasive grains (abrasive grains containing cerium hydroxide) in the CMP polishing solutions of Examples 1 to 15 and Comparative Examples 1 and 2 was measured under the following conditions and was found to be 12 nm. Measurement temperature: 25°C Measurement device: Beckman Coulter, Inc., product name: DelsaMax PRO Measurement method: Approximately 0.5 mL of the CMP polishing solution was placed in a measurement cell (disposable microcuvette) measuring 12.5 mm x 12.5 mm x 45 mm (height), and the cell was then placed in the DelsaMax PRO. The refractive index and viscosity of the measurement sample information were set to 1.333 and 0.887 mPa·s, respectively, and the measurement was performed at 25°C, and the value displayed as Unimodal Size Mean (cumulant diameter) was read.

[0105] (Polishing Rate) The following blanket wafer was polished using the above-mentioned CMP polishing solution under the following CMP polishing conditions.

[0106] [Blanket wafer] A blanket wafer having a silicon oxide film with a thickness of 1000 nm on a silicon substrate (diameter: 300 mm) A blanket wafer having a silicon nitride film with a thickness of 250 nm on a silicon substrate (diameter: 300 mm)

[0107] [CMP Polishing Conditions] Polishing apparatus: FREX 300X (manufactured by Ebara Corporation) CMP polishing solution flow rate: 200 mL / min Polishing substrate: the above-mentioned blanket wafer Polishing pad: foamed polyurethane resin having closed cells (manufactured by ROHM AND HAAS ELECTRONIC MATERIALS CMP INC., model number IC1010) Polishing pressure: 20.7 kPa (3.0 psi) Relative speed between polishing substrate and polishing platen: 100.5 m / min Polishing time: 30 seconds Wafer cleaning: After the CMP treatment, the wafer was washed with water while applying ultrasonic waves, and then dried with a spin dryer.

[0108] [Calculation of Polishing Rate and Polishing Rate Ratio] Using an optical interference film thickness measuring device (device name: F80) manufactured by Filmetrics Inc., the film thickness of the polished film (silicon oxide film and silicon nitride film) was measured at 65 points before and after polishing. The 65 film thickness measurements were performed on a line including the center of the wafer, with the center of the wafer as the reference, at positions of 149 mm, 148 mm, 147 mm, and 145 mm, positions every 5 mm between 145 mm and -145 mm (140 mm, 135 mm, ..., -135 mm, -140 mm), and positions of -145 mm, -147 mm, -148 mm, and -149 mm (distances opposite to positive distances from the wafer center are expressed as negative). The average film thickness values ​​at the 65 points were used to calculate the change in film thickness. Based on the change in film thickness and polishing time, the polishing rates of the polished material (silicon oxide polishing rate RO and silicon nitride polishing rate RN) were calculated using the following formula. The polishing rate ratio (RO / RN) of the polishing rate RO for silicon oxide to the polishing rate RN for silicon nitride was calculated. The results are shown in Table 1. Polishing rate [Å / min] = (film thickness before polishing [Å] - film thickness after polishing [Å]) / polishing time [min]

[0109]

[0110] In the examples, it was confirmed that the polishing rate ratio (RO / RN) of the polishing rate RO of silicon oxide to the polishing rate RN of silicon nitride was 20 or more, and that excellent polishing selectivity of silicon oxide over silicon nitride was obtained.

Claims

1. A polishing liquid comprising an abrasive grain and an acid component, the acid component including a compound having at least one selected from the group consisting of a sulfo group and a sulfonate group (excluding sulfuric acid and its salts), and having a pH of greater than 4.

5.

2. The polishing fluid of claim 1, wherein the abrasive grains comprise cerium hydroxide.

3. The polishing liquid according to claim 1, wherein the acid component comprises an aromatic compound having at least one selected from the group consisting of a sulfo group and a sulfonate group.

4. The polishing liquid according to claim 1, wherein the acid component comprises a compound having no amino group.

5. The polishing liquid according to claim 1, wherein the acid component comprises an aminosulfonic acid compound.

6. The polishing liquid according to claim 1, wherein the acid component comprises at least one selected from the group consisting of sulfanilic acid and its salts.

7. The polishing liquid according to claim 1, wherein the content of the acid component is more than 0.2 mass % based on the total mass of the polishing liquid.

8. The polishing liquid according to claim 1, further comprising a nonionic polymer.

9. The polishing fluid according to claim 8, wherein the nonionic polymer comprises a glycerin-based polymer.

10. The polishing liquid according to claim 1, further comprising a base component.

11. The polishing liquid according to claim 1, which is used for polishing a surface to be polished that contains silicon oxide and silicon nitride.

12. A polishing method comprising a step of polishing a surface to be polished with the polishing liquid according to any one of claims 1 to 11.

13. The polishing method according to claim 12, wherein the surface being polished comprises silicon oxide and silicon nitride.

14. A method for manufacturing a part, comprising a step of obtaining a part using a polished member polished by the polishing method according to claim 12.

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