Abrasive grain, slurry, polishing method, component fabrication method, and semiconductor component fabrication method

Abstract

Provided is an abrasive grain for polishing silicon nitride, the abrasive grain containing cerium-based particles, the cerium-based particles being surface-treated with a silane compound. Provided is a slurry containing the abrasive grain. Provided is a polishing method comprising a step for polishing, by using the slurry, a silicon nitride–containing member to be polished. Provided is a component fabrication method comprising a step for obtaining a component by using the member to be polished that has been polished according to the polishing method. Provided is a semiconductor component fabrication method comprising a step for obtaining a semiconductor component by using the member to be polished that has been polished according to the polishing method.

Description

Abrasive grains, slurry, polishing method, method for manufacturing parts, and method for manufacturing semiconductor parts.

[0001] This disclosure relates to abrasive grains, slurry, polishing methods, methods for manufacturing parts, methods for manufacturing semiconductor parts, etc.

[0002] In the field of semiconductor manufacturing, as ultra-large-scale integrated circuits (ULSIs) become more powerful, it is becoming increasingly difficult to achieve both high integration and high speed through miniaturization techniques that are merely extensions of conventional technologies. Therefore, technologies are being developed that allow for both miniaturization of semiconductor elements and high integration in the vertical direction (i.e., technologies for multi-layer wiring).

[0003] One of the most important technologies in the manufacturing process of devices with multilayer wiring is CMP (chemical mechanical polishing) technology. For example, planarization by CMP is essential to ensure the depth of focus in lithography. If there are irregularities on the surface of the workpiece after polishing, problems such as inability to focus during the exposure process or inability to adequately form fine wiring structures will occur. Furthermore, CMP technology is used in the device manufacturing process to create plasma oxide films (BPSG, HDP-SiO ２ This process is also applicable to steps such as forming element isolation (inter-element isolation; STI: shallow trench isolation) regions by polishing (p-TEOS, etc.); forming ILD films (interlayer insulating films; insulating films that electrically insulate metal components (wiring, etc.) from each other in the same layer); and planarizing plugs (e.g., Al-Cu plugs) after embedding metal wiring in a film containing silicon oxide.

[0004] CMP can be performed using a device capable of supplying polishing fluid onto a polishing pad. The surface of the workpiece is polished by supplying polishing fluid between the workpiece and the polishing pad while pressing the workpiece against the polishing pad. Thus, in CMP technology, the polishing fluid is one of the key technologies, and various polishing fluids have been developed to obtain high-performance polishing fluids (see, for example, Patent Document 1 below).

[0005] Among the processes to which the above-described CMP technology is applied, the CMP process for ILD films, in particular, requires polishing silicon oxide at a high polishing rate. For this reason, silica-based polishing solutions (polishing solutions using abrasive grains containing silica-based particles) with high polishing rates are mainly used in the CMP process for ILD films (see, for example, Patent Document 2 below). However, with silica-based polishing solutions, it is difficult to control polishing scratches, which are the cause of defects. Furthermore, with the miniaturization of wiring in recent years, it is desirable to reduce polishing scratches in the CMP process for ILD films as well, but unlike the CMP process for insulating films for element isolation regions, finish mirror polishing is generally not performed. For this reason, the use of cerium-based polishing solutions (polishing solutions using abrasive grains containing cerium-based particles), which produce fewer polishing scratches compared to silica-based polishing solutions, is being considered (see, for example, Patent Document 3 below).

[0006] JP 2008-288537 JP 9-316431 JP 10-102038

[0007] For slurries that can be used as cerium-based polishing fluids, it is sometimes necessary to obtain a high polishing speed for silicon nitride abrasive grains.

[0008] One aspect of this disclosure aims to provide abrasive grains capable of achieving a high polishing speed of silicon nitride. Another aspect of this disclosure aims to provide a slurry containing such abrasive grains. Another aspect of this disclosure aims to provide a polishing method using such a slurry. Another aspect of this disclosure aims to provide a method for manufacturing parts using such a polishing method. Another aspect of this disclosure aims to provide a method for manufacturing semiconductor parts using such a polishing method.

[0009] This disclosure includes the following aspects: [1] Abrasive grains for polishing silicon nitride, comprising cerium-based particles, wherein the cerium-based particles are surface-treated with a silane compound. [2] The abrasive grain according to [1], wherein the silane compound has a primary amino group. [3] The abrasive grain according to [1] or [2], wherein the silane compound comprises an aminoalkyltrialkoxysilane. [4] The abrasive grain according to any one of [1] to [3], wherein the silane compound has a secondary amino group. [5] The abrasive grain according to [4], wherein the number of secondary amino groups in the silane compound is 1. [6] The abrasive grain according to [4], wherein the number of secondary amino groups in the silane compound is 2. [7] The abrasive grain according to any one of [1] to [6], wherein the silane compound has a tertiary amino group. [8] The abrasive grain according to any one of [1] to [7], wherein the silane compound has a heterocycle. [9] The abrasive grain according to [8], wherein the heterocycle comprises an oxirane ring.

[10] Abrasive grain according to [8] or [9], wherein the heterocycle comprises a morpholine ring.

[11] Abrasive grain according to any one of [1] to

[10] , wherein the silane compound has a urea bond.

[12] Abrasive grain according to any one of [1] to

[11] , wherein the particle size D50 is less than 10.0 nm.

[13] A slurry containing abrasive grain according to any one of [1] to

[12] .

[14] A slurry according to

[13] , wherein the pH is 3.0 to 10.0.

[15] A slurry according to

[13] , wherein the pH is 4.0 to 6.0.

[16] A polishing method comprising the step of polishing a workpiece containing silicon nitride using a slurry according to any one of

[13] to

[15] .

[17] A method for manufacturing a part, comprising the step of obtaining a part using a workpiece polished by the polishing method according to

[16] .

[18] A method for manufacturing a semiconductor part, comprising the step of obtaining a semiconductor part using a workpiece polished by the polishing method according to

[16] .

[0010] According to one aspect of this disclosure, it is possible to provide abrasive grains capable of achieving a high polishing speed of silicon nitride. According to another aspect of this disclosure, it is possible to provide a slurry containing such abrasive grains. According to another aspect of this disclosure, it is possible to provide a polishing method using such a slurry. According to another aspect of this disclosure, it is possible to provide a method for manufacturing a component using such a polishing method. According to another aspect of this disclosure, it is possible to provide a method for manufacturing a semiconductor component using such a polishing method.

[0011] The embodiments of this disclosure will be described in detail below.

[0012] In this specification, numerical ranges indicated using "~" represent a range that includes the numbers listed before and after "~" as the minimum and maximum values, respectively. "A or greater" in a numerical range means A and the range greater than A. "A or less" in a numerical range means A and the range less than A. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step can be arbitrarily combined with the upper or lower limit of a numerical range in another step. In numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. "A or B" means that either A or B may be included, or both A and B may be included. Unless otherwise specified, the materials exemplified in this specification can be used individually or in combination of two or more. The content of each component in a composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component in the composition, unless otherwise specified. The term "membrane" encompasses not only structures formed across the entire surface when observed in a plan view, but also structures formed in only a portion of it. The term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from others, as long as their intended function is achieved. Unless otherwise specified, alkyl groups may be linear, branched, or cyclic.

[0013] The abrasive grains according to this embodiment are abrasive grains for polishing silicon nitride, and contain cerium-based particles, the cerium-based particles being surface-treated with a silane compound. Hereinafter, the cerium-based particles surface-treated with a silane compound will be referred to as "cerium-based particles P". The abrasive grains according to this embodiment may contain cerium-based particles P and particles other than cerium-based particles P (for example, cerium-based particles not surface-treated with a silane compound).

[0014] The abrasive grains according to this embodiment can achieve a high polishing rate for silicon nitride. According to the abrasive grains according to this embodiment, in the evaluation described in the [Examples] below, a relative ratio of the silicon nitride polishing rate of, for example, 1.10 or higher (preferably 1.30 or higher, 1.40 or higher, 1.50 or higher, 2.00 or higher, 2.50 or higher, etc.) can be obtained. When silicon nitride is polished using a slurry containing abrasive grains including cerium-based particles, ammonia may be generated locally. In this case, the cerium-based particles may aggregate due to a change in the pH of the slurry (e.g., an increase), potentially reducing the polishing rate. On the other hand, with the abrasive grains according to this embodiment, since the cerium-based particles are surface-treated with a silane compound, the zeta potential of the cerium-based particles can be easily adjusted. Therefore, even if ammonia is generated and the pH of the slurry changes, aggregation of cerium-based particles is suppressed, which is presumed to result in a high polishing rate for silicon nitride. However, the factors that contribute to achieving a high polishing rate for silicon nitride are not limited to the above.

[0015] The abrasive grains according to this embodiment, and the techniques using such abrasive grains, may be used to polish any material to be polished, may be used to polish silicon nitride, or may be used to polish materials other than silicon nitride, as long as they have the characteristic of being able to achieve a high polishing speed of silicon nitride.

[0016] Cerium-based particles are particles containing cerium and may contain cerium compounds. Examples of cerium compounds include cerium oxide, cerium hydroxide, cerium ammonium nitrate, cerium acetate, cerium sulfate hydrate, cerium bromate, cerium bromide, cerium chloride, cerium oxalate, cerium nitrate, and cerium carbonate. The abrasive grains according to this embodiment may contain components other than cerium compounds. Examples of such components include silicon oxide, aluminum oxide, silicon nitride, zirconium oxide, titanium oxide, yttrium oxide, and silicon carbide.

[0017] The cerium compound content in the abrasive grains 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, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 92% by mass or more, 93% by mass or more, 95% by mass or more, 97% by mass or more, 98% by mass or more, or 99% by mass or more, based on the total mass of the abrasive grains (total mass of abrasive grains contained in the slurry), from the viewpoint of easily obtaining a high polishing speed of silicon nitride.

[0018] In the abrasive grains according to this embodiment, the cerium-based particles are surface-treated with a silane compound. In the abrasive grains according to this embodiment, at least one selected from the group consisting of silane compounds and compounds derived from silane compounds may be present on the surface of the cerium-based particles.

[0019] From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may have a trialkoxysilyl group. The trialkoxysilyl group has three alkoxy groups bonded to the silicon atom, and the number of carbon atoms of the three alkoxy groups may be the same or different. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the number of trialkoxysilyl groups in the silane compound may be 1 to 3 or 1 to 2 or 1. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the trialkoxysilyl group in the silane compound may have alkoxy groups with 1 to 5, 1 to 4, 1 to 3, or 1 to 2 carbon atoms bonded to the silicon atom. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the trialkoxysilyl group in the silane compound may have 1 to 3 or 2 to 3 methoxy groups bonded to the silicon atom. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may contain aminoalkyltrialkoxysilane.

[0020] From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may have at least one selected from the group consisting of primary amino groups, secondary amino groups, and tertiary amino groups, and may have both primary and secondary amino groups. The silane compound may have a primary amino group, or it may not have a primary amino group. The silane compound may have a secondary amino group, or it may not have a secondary amino group. The silane compound may have a tertiary amino group, or it may not have a tertiary amino group.

[0021] The silane compound may have a secondary amino group that constitutes a heterocycle, and may also have a secondary amino group that does not constitute a heterocycle, from the viewpoint of easily obtaining a high polishing rate for silicon nitride. The silane compound may have a tertiary amino group that does not constitute a heterocycle, and may also have a tertiary amino group that constitutes a heterocycle, from the viewpoint of easily obtaining a high polishing rate for silicon nitride.

[0022] The following numbers of amino groups in the silane compound may be within the following ranges, from the viewpoint of easily obtaining a high polishing rate for silicon nitride. The number of primary amino groups may be 1 to 5, 1 to 4, 1 to 3, or 1 to 2, or 1. The number of secondary amino groups may be 1 to 5, 1 to 4, 1 to 3, 1 to 2, 2 to 5, 2 to 4, or 2 to 3, or 1, or 2. The number of tertiary amino groups may be 1 to 5, 1 to 4, 1 to 3, or 1 to 2, or 1. The total number of primary and secondary amino groups may be 1 to 5, 1 to 4, 1 to 3, 1 to 2, 2 to 5, 2 to 4, 2 to 3, 3 to 5, or 3 to 4. The total number of primary and tertiary amino groups may be 1 to 5, 1 to 4, 1 to 3, or 1 to 2, or 1. The total number of secondary and tertiary amino groups may be 1-5, 1-4, 1-3, 1-2, 2-5, 2-4, or 2-3. The total number of primary, secondary, and tertiary amino groups may be 1-5, 1-4, 1-3, 1-2, 2-5, 2-4, 2-3, 3-5, or 3-4.

[0023] From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may have at least one selected from the group consisting of alkyl group A11, which is bonded to a silicon atom (e.g., a silicon atom of a trialkoxysilyl group) and a primary amino group; alkyl group A12, which is bonded to a silicon atom (e.g., a silicon atom of a trialkoxysilyl group) and a secondary amino group; and alkyl group A13, which is bonded to a silicon atom (e.g., a silicon atom of a trialkoxysilyl group) and a tertiary amino group. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the number of carbon atoms in the at least one selected from the group consisting of alkyl group A11, alkyl group A12, and alkyl group A13 may be 1 to 5, 1 to 4, 1 to 3, 2 to 5, 2 to 4, 2 to 3, 3 to 5, or 3 to 4.

[0024] From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may have an alkyl group A21 to which two nitrogen atoms are bonded, an alkyl group A22 to which two secondary amino groups are bonded, and an alkyl group A23 to which one primary amino group and one secondary amino group are bonded. The number of carbon atoms in at least one element selected from the group consisting of alkyl group A21, alkyl group A22, and alkyl group A23 may be 1 to 8, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 1 to 2, 2 to 8, 2 to 6, 2 to 5, 2 to 4, 2 to 3, 3 to 8, 3 to 6, 3 to 5, 3 to 4, 4 to 8, 4 to 6, 4 to 5, 5 to 8, 5 to 6, or 6 to 8.

[0025] Silane compounds may or may not have heterocycles. Heterocycles may or may not have nitrogen atoms. Heterocycles may or may not have oxygen atoms. Examples of heterocycles include oxirane rings (epoxy rings, epoxy groups), morpholine rings, imidazole rings, pyrazole rings, pyridine rings, pyrimidine rings, pyrrole rings, indole rings, triazine rings, etc. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the heterocycle may include at least one selected from the group consisting of oxirane rings and morpholine rings, and may include oxirane rings or morpholine rings. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the number of heterocycles in the silane compound may be 1 to 3 or 1 to 2, or may be 1.

[0026] The silane compound may have an ether group, but may not have an ether group from the viewpoint of easily obtaining a high polishing rate of silicon nitride. The silane compound may have an ether group E1 constituting a heterocycle, and may have an ether group E2 that does not constitute a heterocycle, from the viewpoint of easily obtaining a high polishing rate of silicon nitride. The following numbers of ether groups in the silane compound may be within the following ranges from the viewpoint of easily obtaining a high polishing rate of silicon nitride. The number of ether groups (total of ether groups E1 and ether groups E2) may be 1 to 5, 1 to 4, 1 to 3, 1 to 2, 2 to 5, 2 to 4, or 2 to 3. The number of ether groups E1 may be 1 to 5, 1 to 4, 1 to 3, or 1 to 2, and may be 1. The number of ether groups E2 may be 1 to 5, 1 to 4, 1 to 3, or 1 to 2, and may be 1.

[0027] From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may have a glycidyl group and may have a glycidyloxy group. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may have an alkyl group to which a silicon atom (e.g., a silicon atom of a trialkoxysilyl group) and a glycidyloxy group are bonded. From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the number of carbon atoms in such an alkyl group may be 1 to 5, 1 to 4, 1 to 3, 2 to 5, 2 to 4, 2 to 3, 3 to 5, or 3 to 4.

[0028] From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may have an alkyl group to which a silicon atom (e.g., a silicon atom of a trialkoxysilyl group) and a heterocycle are bonded, or it may have an alkyl group to which a silicon atom (e.g., a silicon atom of a trialkoxysilyl group) and a morpholine ring are bonded. The number of carbon atoms in such alkyl groups may be 1 to 5, 1 to 4, 1 to 3, 2 to 5, 2 to 4, 2 to 3, 3 to 5, or 3 to 4, from the viewpoint of easily obtaining a high polishing rate of silicon nitride.

[0029] The silane compound may or may not have urea bonds. The number of urea bonds in the silane compound may be 1 to 3 or 1 to 2, or 1, from the viewpoint of easily obtaining a high polishing rate of silicon nitride.

[0030] Silane compounds may have a functional group containing a heteroatom (excluding a functional group corresponding to a trialkoxysilyl group) from the viewpoint of easily obtaining a high polishing rate of silicon nitride, and may have a trialkoxysilyl group and a functional group containing a heteroatom (excluding a functional group corresponding to a trialkoxysilyl group). Examples of heteroatoms include nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms, etc.

[0031] The silane compound may include at least one selected from the group consisting of aminoalkyltrialkoxysilane, glycidyloxyalkyltrialkoxysilane, [(aminoalkylamino)alkyl]trialkoxysilane, [(aminoalkylamino)alkylamino]alkyltrialkoxysilane, [(trialkoxysilyl)alkyl]morpholine, and [(trialkoxysilyl)alkyl]urea, from the viewpoint of easily obtaining a high polishing rate of silicon nitride. It may contain at least one selected from the group consisting of dimethoxysilane, [(trimethoxysilyl)alkyl]morpholine, and [(trimethoxysilyl)alkyl]urea, and may also contain at least one selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, [3-(2-aminoethylamino)propyl]trimethoxysilane, [3-(6-aminohexylamino)propyl]trimethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, 4-[3-(trimethoxysilyl)propyl]morpholine, and 1-[3-(trimethoxysilyl)propyl]urea.

[0032] From the viewpoint of easily obtaining a high polishing rate of silicon nitride, the silane compound may include compounds that do not have an aromatic ring, compounds that do not have an aryl group, compounds that do not have a phenyl group, and compounds that do not contain a sulfur atom.

[0033] The particle size D50 of the abrasive grains according to this embodiment (50% cumulative diameter in the mass-based cumulative particle size distribution curve) may be within the following range, from the viewpoint of easily obtaining a high polishing speed for silicon nitride. The particle size D50 may be 100 nm or less, 80.0 nm or less, 50.0 nm or less, 40.0 nm or less, 30.0 nm or less, 25.0 nm or less, 20.0 nm or less, 15.0 nm or less, 12.0 nm or less, 10.0 nm or less, less than 10.0 nm, 9.5 nm or less, 9.0 nm or less, 8.5 nm or less, 8.0 nm or less, 7.5 nm or less, 7.0 nm or less, 6.5 nm or less, 6.2 nm or less, 6.1 nm or less, 6.0 nm or less, 5.5 nm or less, or 5.0 nm or less. The particle size D50 may be 0.10 nm or larger, 0.50 nm or larger, 1.0 nm or larger, 1.5 nm or larger, 2.0 nm or larger, 2.5 nm or larger, 3.0 nm or larger, 3.5 nm or larger, 4.0 nm or larger, 4.5 nm or larger, 5.0 nm or larger, 5.5 nm or larger, 6.0 nm or larger, 6.1 nm or larger, 6.2 nm or larger, 6.5 nm or larger, 7.0 nm or larger, 7.5 nm or larger, or 8.0 nm or larger. From these perspectives, the particle size D50 may be 0.10 to 100 nm, 0.10 to 50.0 nm, 0.10 nm or more and less than 10.0 nm, 0.10 to 8.0 nm, 1.0 to 100 nm, 1.0 to 50.0 nm, 1.0 nm or more and less than 10.0 nm, 1.0 to 8.0 nm, 4.0 to 100 nm, 4.0 to 50.0 nm, 4.0 nm or more and less than 10.0 nm, or 4.0 to 8.0 nm.

[0034] The particle size D90 of the abrasive grains according to this embodiment (90% cumulative diameter in the mass-based cumulative particle size distribution curve) may be within the following range, from the viewpoint of easily obtaining a high polishing speed for silicon nitride. The particle size D90 may be 200 nm or less, 160 nm or less, 150 nm or less, 120 nm or less, 100 nm or less, 80.0 nm or less, 60.0 nm or less, 50.0 nm or less, 40.0 nm or less, 30.0 nm or less, 25.0 nm or less, 20.0 nm or less, less than 20.0 nm, 18.0 nm or less, 16.0 nm or less, 15.0 nm or less, 14.5 nm or less, 14.0 nm or less, 13.5 nm or less, 13.0 nm or less, 12.5 nm or less, 12.0 nm or less, 11.7 nm or less, 11.6 nm or less, 11.5 nm or less, 11.0 nm or less, 10.5 nm or less, 10.0 nm or less, 9.5 nm or less, 9.0 nm or less, or 8.5 nm or less. The particle size D90 may be 1.0 nm or larger, 2.0 nm or larger, 3.0 nm or larger, 4.0 nm or larger, 5.0 nm or larger, 5.5 nm or larger, 6.0 nm or larger, 6.5 nm or larger, 7.0 nm or larger, 7.5 nm or larger, 8.0 nm or larger, 8.5 nm or larger, 9.0 nm or larger, 9.5 nm or larger, 10.0 nm or larger, 10.5 nm or larger, 11.0 nm or larger, 11.5 nm or larger, 11.6 nm or larger, 11.7 nm or larger, 12.0 nm or larger, or 12.5 nm or larger. From these perspectives, the particle size D90 may be 1.0–200 nm, 1.0–100 nm, 1.0–50.0 nm, 1.0–15.0 nm, 5.0–200 nm, 5.0–100 nm, 5.0–50.0 nm, 5.0–15.0 nm, 8.0–200 nm, 8.0–100 nm, 8.0–50.0 nm, or 8.0–15.0 nm.

[0035] The particle sizes D50 and D90 of the abrasive grains in this embodiment may be the particle sizes of the abrasive grains in the slurry, or they may be the particle sizes of the abrasive grains before obtaining the slurry. The particle sizes D50 and D90 of the abrasive grains can be measured by the method described in the [Examples] below.

[0036] In this embodiment, the zeta potential (at 25°C) of the abrasive grains may be positive in the slurry. Since silicon nitride tends to have a negative zeta potential, if the zeta potential of the abrasive grains is positive, the abrasive grains are more likely to approach silicon nitride, making it easier to obtain a high polishing speed for silicon nitride.

[0037] The zeta potential (25°C) of the abrasive grains according to the present embodiment may be within the following range. Since the abrasive grains tend to approach silicon nitride, from the viewpoint of easily obtaining a high polishing rate of silicon nitride, it may be more than 0 mV, 5 mV or more, 10 mV or more, 12 mV or more, 15 mV or more, 18 mV or more, or 20 mV or more. The zeta potential of the abrasive grains is adjusted so that the relationship of the zeta potential is appropriately adjusted without excessive deviation of the zeta potential of the abrasive grains from the zeta potential of silicon nitride, and the abrasive grains can be desorbed without excessive adsorption to silicon nitride. Therefore, from the viewpoint of easily obtaining a high polishing rate of silicon nitride, it may be 100 mV or less, 90 mV or less, 80 mV or less, 75 mV or less, 70 mV or less, 65 mV or less, 60 mV or less, or 55 mV or less. From these viewpoints, the zeta potential of the abrasive grains may be more than 0 mV and 100 mV or less, more than 0 mV and 80 mV or less, more than 0 mV and 60 mV or less, more than 0 mV and 55 mV or less, 10 to 100 mV, 10 to 80 mV, 10 to 60 mV, 10 to 55 mV, 20 to 100 mV, 20 to 80 mV, 20 to 60 mV, or 20 to 55 mV. The zeta potential of the abrasive grains can be measured by the method described in [Examples] below.

[0038] In the abrasive grains according to the present embodiment, the content of the cerium-based particles P is 50% by mass or more, more than 50% by mass, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 93% by mass or more, 95% by mass or more, 98% by mass or more, or 99% by mass or more based on the total mass of the abrasive grains (the total mass of the abrasive grains contained in the slurry) from the viewpoint of easily obtaining a high polishing rate of silicon nitride. The abrasive grains according to the present embodiment may be in a mode substantially composed of cerium-based particles P (a mode in which substantially 100% by mass of the abrasive grains are cerium-based particles P).

[0039] The method for producing abrasive grains according to the present embodiment includes a surface treatment step of surface-treating cerium-based particles with a silane compound. In the surface treatment step, the silane compound may be brought into contact with the surface of the cerium-based particles, and the silane compound may be brought into contact with the surface of the cerium-based particles by stirring a liquid containing the cerium-based particles and the silane compound.

[0040] The slurry according to this embodiment contains abrasive grains according to this embodiment. The slurry according to this embodiment can be used as a slurry for polishing silicon nitride, can be used as a cerium-based polishing liquid, and can be used as a CMP polishing liquid.

[0041] As the content of the abrasive grains according to this embodiment or the content of the cerium-based particles P, the content C may be in the following range based on the total mass of the slurry from the viewpoint of easily obtaining a high polishing rate of silicon nitride. The content C may be 0.001% by mass or more, 0.005% by mass or more, 0.010% by mass or more, 0.015% by mass or more, 0.020% by mass or more, 0.025% by mass or more, 0.030% by mass or more, 0.035% by mass or more, 0.040% by mass or more, 0.045% by mass or more, or 0.050% by mass or more. The content C may be 1.000% by mass or less, 0.800% by mass or less, 0.500% by mass or less, 0.300% by mass or less, 0.250% by mass or less, 0.200% by mass or less, 0.150% by mass or less, 0.100% by mass or less, 0.080% by mass or less, or 0.050% by mass or less. From these viewpoints, the content C may be 0.001 to 1.000% by mass, 0.001 to 0.500% by mass, 0.001 to 0.100% by mass, 0.005 to 1.000% by mass, 0.005 to 0.500% by mass, 0.005 to 0.100% by mass, 0.010 to 1.000% by mass, 0.010 to 0.500% by mass, or 0.010 to 0.100% by mass.

[0042] The slurry according to this embodiment may contain water. The water is not particularly limited, and examples thereof include deionized water, ion-exchanged water, and ultrapure water.

[0043] The slurry according to this embodiment may contain additives (components that do not correspond to abrasive grains and water). Examples of such additives include acid components, bases, polymer compounds, organic solvents (such as ethanol and acetone).

[0044] The slurry according to this embodiment may contain at least one selected from the group consisting of acidic components and bases, or it may not contain at least one selected from the group consisting of acidic components and bases. The acidic component may include an inorganic acid component or an organic acid component. The inorganic acid component may include at least one selected from the group consisting of inorganic acids and inorganic salts. Examples of inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, boric acid, etc. Examples of inorganic salts include metal salts such as alkali metal salts and alkaline earth metal salts. The organic acid component may include at least one selected from the group consisting of organic acids and organic salts. Examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, lactic acid, maleic acid, phthalic acid, citric acid, succinic acid, etc. Examples of organic salts include ammonium salts, alkali metal salts, and alkaline earth metal salts. Examples of bases include metal hydroxides and amine compounds. Examples of metal hydroxides include sodium hydroxide, potassium hydroxide, and calcium hydroxide. Examples of amine compounds include tris(hydroxyalkyl)aminomethane (e.g., tris(hydroxymethyl)aminomethane), diethanolamine, dimethylethanolamine, diethylethanolamine, triethanolamine, and other alkanolamines. The slurry according to this embodiment may contain an acid component, an inorganic acid component, at least one selected from the group consisting of acetic acid and acetate salts, a base, an amine compound, an alkanolamine, and tris(hydroxyalkyl)aminomethane (e.g., tris(hydroxymethyl)aminomethane), from the viewpoint of easily obtaining a high polishing rate of silicon nitride.

[0045] The pH (at 25°C) of the slurry according to this embodiment may be within the following range, from the viewpoint of easily obtaining a high polishing rate for silicon nitride. The pH may be 1.0 or higher, 1.5 or higher, 2.0 or higher, greater than 2.0, 2.5 or higher, 3.0 or higher, greater than 3.0, 3.5 or higher, 4.0 or higher, greater than 4.0, 4.2 or higher, 4.5 or higher, 4.8 or higher, 5.0 or higher, greater than 5.0, 5.2 or higher, 5.5 or higher, 5.8 or higher, 6.0 or higher, greater than 6.0, 6.2 or higher, 6.5 or higher, 6.8 or higher, 7.0 or higher, greater than 7.0, 7.2 or higher, 7.5 or higher, 7.8 or higher, 8.0 or higher, greater than 8.0, 8.2 or higher, 8.5 or higher, 8.8 or higher, or 9.0 or higher. The pH may be 13.0 or less, 12.5 or less, 12.0 or less, 11.5 or less, 11.0 or less, 10.5 or less, 10.0 or less, less than 10.0, 9.5 or less, 9.0 or less, less than 9.0, 8.8 or less, 8.5 or less, 8.2 or less, 8.0 or less, less than 8.0, 7.8 or less, 7.5 or less, 7.2 or less, 7.0 or less, less than 7.0, 6.8 or less, 6.5 or less, 6.2 or less, 6.0 or less, less than 6.0, 5.8 or less, 5.5 or less, 5.2 or less, 5.0 or less, less than 5.0, 4.8 or less, 4.5 or less, 4.2 or less, or 4.0 or less. From these viewpoints, the pH may be 1.0 to 13.0, 1.0 to 10.0, 1.0 to 8.0, 1.0 to 6.0, 3.0 to 13.0, 3.0 to 10.0, 3.0 to 8.0, 3.0 to 6.0, 4.0 to 13.0, 4.0 to 10.0, 4.0 to 8.0, or 4.0 to 6.0. The pH can be measured by the method described in the [Examples] below. The pH of the slurry according to this embodiment may vary depending on the type and content of the components contained in the slurry. Furthermore, when surface treatment of cerium particles is performed by contacting the silane compound with the surface of the cerium particles in a liquid containing cerium particles and a silane compound, the pH of the liquid containing cerium particles after surface treatment may also change depending on the type of silane compound. Such a liquid may be used as is as slurry (slurry according to this embodiment), or additives may be added to such a liquid to obtain slurry (slurry according to this embodiment).

[0046] The slurry according to this embodiment may be stored as a storage liquid with a reduced amount of water compared to that used during polishing. One embodiment of the slurry according to this embodiment may be such a storage liquid. The storage liquid can be used by diluting it with water before or during polishing.

[0047] The polishing method according to this embodiment comprises a polishing step of polishing a member to be polished using a slurry according to this embodiment. The member to be polished may contain silicon nitride, or it may contain a material to be polished other than silicon nitride. The shape of the member to be polished is not particularly limited and may be, for example, a film. In the polishing step, it is possible to polish the surface of the member to be polished, and the surface to be polished in which silicon nitride is present may be polished. In the polishing step, at least a part of the member to be polished can be polished and removed. The member to be polished is not particularly limited and may be a wafer (e.g., a semiconductor wafer) or a chip (e.g., a semiconductor chip). The member to be polished may be a wiring board or a circuit board.

[0048] The method for manufacturing a component according to this embodiment includes a component manufacturing step of obtaining a component using a member to be polished by the polishing method according to this embodiment. The component according to this embodiment is a component obtained by the method for manufacturing a component according to this embodiment. The component according to this embodiment is not particularly limited, but 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 embodiment of the method for manufacturing a component according to this embodiment, the method for manufacturing an electronic component according to this embodiment obtains an electronic component using a member to be polished by the polishing method according to this embodiment. As one embodiment of the method for manufacturing a component according to this embodiment, the method for manufacturing a semiconductor component according to this embodiment obtains a semiconductor component (e.g., a semiconductor package) using a member to be polished by the polishing method according to this embodiment. The method for manufacturing a component according to this embodiment may include a polishing step of polishing the member to be polished by the polishing method according to this embodiment before the component manufacturing step.

[0049] As one aspect of the component manufacturing process according to this embodiment, the component manufacturing process may include a piece-forming step in which the member to be polished by the polishing method according to this embodiment is pieced into individual pieces. The piece-forming 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 a chip (e.g., a semiconductor chip). As one aspect of the component manufacturing process according to this embodiment, the electronic component manufacturing process according to this embodiment may include a step of obtaining an electronic component (e.g., a semiconductor component) by piece-forming the member to be polished by the polishing method according to this embodiment. As one aspect of the component manufacturing process according to this embodiment, the semiconductor component manufacturing process according to this embodiment may include a step of obtaining a semiconductor component (e.g., a semiconductor package) by piece-forming the member to be polished by the polishing method according to this embodiment.

[0050] The method for manufacturing a part according to this embodiment may include, as one aspect of the part manufacturing process, a connection step of connecting (for example, electrically connecting) a member to be polished by the polishing method according to this embodiment to another connected body. The connected body connected to the member to be polished by the polishing method according to this embodiment is not particularly limited and may be the member to be polished by the polishing method according to this embodiment, or it may be a connected body different from the member to be polished by the polishing method according to this embodiment. In the connection step, the member to be polished and the connected body may be directly connected (connected in a state where the member to be polished and the connected body are in contact), or they may be connected via another member (such as a conductive member). The connection step can be performed before the individualization step, after the individualization step, or before and after the individualization step.

[0051] The connection step may be a step of connecting the surface of the member to be polished, which has been polished by the polishing method according to this embodiment, to the connected body, or a step of connecting the connecting surface of the member to be polished, which has been polished by the polishing method according to this embodiment, to the connecting surface of the connected body. The connecting surface of the member to be polished may be the surface of the member to be polished, which has been polished by the polishing method according to this embodiment. By the connection step, a connected body comprising the member to be polished and the connected body can be obtained. In the connection step, if the connecting surface of the member to be polished has a metal part, the connected body may be brought into contact with the metal part. In the connection step, if the connecting surface of the member to be polished has a metal part and the connecting surface of the connected body has a metal part, the metal parts may be brought into contact with each other. The metal part may contain copper.

[0052] The device according to this embodiment (for example, an electronic device such as a semiconductor device) comprises a member to be polished by the polishing method according to this embodiment, and at least one selected from the group consisting of the component according to this embodiment.

[0053] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0054] <Preparation of cerium compound particles> First, 7603g of water was placed in a container. Next, a 50% by mass aqueous solution of cerium ammonium nitrate (Ce(NH)) was added to this container. ４ ) ２ (NO ３ ) ６ A metal salt aqueous solution was obtained by adding 1037 g of (formula weight 548.2 g / mol, manufactured by Nippon Chemical Industrial Co., Ltd., product name: 50% CAN solution) and mixing, and then adjusting the liquid temperature to 40°C.

[0055] Next, imidazole was dissolved in water to obtain 4566 g of an aqueous solution with a concentration of 0.7 mol / L, and then the solution temperature was adjusted to 20-25°C to obtain an alkaline solution.

[0056] The container holding the above metal salt aqueous solution was placed in a water tank, and the water temperature in the tank was adjusted to 40°C using an external circulation device, the Coolnics Circulator (manufactured by Tokyo Rikakikai Co., Ltd. (EYELA), product name: Cooling Thermo Pump CTP101). The temperature of the metal salt aqueous solution was maintained at 40°C, and a stirring speed of 400 min was maintained using a 3-blade pitch paddle with a blade length of 5 cm. －１ While stirring the metal salt aqueous solution, add 0.0000085 ml of the above alkaline solution. ３ By adding it to the container at a mixing rate of 8.5 mL / min, a slurry precursor 1 (pH: 2.2) containing abrasive particles including cerium compound particles was obtained.

[0057] Slurry precursor 2 was obtained by ultrafiltration of slurry precursor 1 while circulating it using a hollow fiber filter with a fractionation molecular weight of 50,000. In ultrafiltration, ions were removed until the conductivity was 50 mS / m or less. Ultrafiltration was performed by adding water to maintain a constant water level in the tank containing slurry precursor 1 using a liquid level sensor. By adding water to slurry precursor 2 and adjusting the abrasive content to 1.0 mass%, slurry precursor 3 containing cerium compound particles was obtained.

[0058] <Surface treatment of cerium compound particles> The cerium compound particles in Examples 1 to 22 were surface-treated according to the following procedure.

[0059] An aqueous solution of the surface treatment agent was obtained by dissolving the surface treatment agent in water and then stirring it at 25°C for 15 minutes. The following compounds shown in Table 1 were used as the surface treatment agent. 3-aminopropyltrimethoxysilane: manufactured by FUJIFILM Wako Pure Chemical Corporation 3-glycidyloxypropyltrimethoxysilane: manufactured by FUJIFILM Wako Pure Chemical Corporation [3-(6-aminohexylamino)propyl]trimethoxysilane: manufactured by Tokyo Chemical Industry Co., Ltd. 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane: manufactured by Tokyo Chemical Industry Co., Ltd. [3-(2-aminoethylamino)propyl]trimethoxysilane: manufactured by Tokyo Chemical Industry Co., Ltd. 4-[3-(trimethoxysilyl)propyl]morpholine: manufactured by FUJIFILM Wako Pure Chemical Corporation 1-[3-(trimethoxysilyl)propyl]urea: manufactured by Tokyo Chemical Industry Co., Ltd.

[0060] After putting the above slurry precursor 3 into a container, the slurry precursor 3 was stirred at a temperature of 25°C and a stirring speed of 700 min －１ for 5 minutes. Next, an aqueous solution of the above surface treatment agent (content of the surface treatment agent: 0.6% by mass) was mixed into this container to obtain a mixed solution, and then the liquid temperature of this mixed solution was adjusted to 60°C. Then, the mixed solution was stirred at a stirring speed of 700 min －１ for 2 hours to obtain a suspension.

[0061] Using a hollow fiber filter with a molecular weight cut-off of 50,000, ultrafiltration was performed while circulating the above suspension to obtain Slurry A containing 1.0% by mass (basis: total mass of Slurry A) of abrasive grains containing surface-treated cerium compound particles. In the ultrafiltration, ionic components were removed until the conductivity became 30 mS / m or less. The ultrafiltration was performed while adding water using a liquid level sensor to keep the water level in the tank containing the suspension constant.

[0062] <Preparation of Polishing Slurry> (Examples 1-22) By mixing a pH adjusting agent and pure water with the above slurry A, slurry B (polishing slurry) containing 0.05% by mass (based on the total mass of slurry B) of abrasive grains containing surface-treated cerium compound particles was obtained. Acetic acid was used as the pH adjusting agent in Examples 1, 7-12, 14-18 and 21, and tris(hydroxymethyl)aminomethane was used in Examples 2-6, 13, 19-20 and 22. The content of the pH adjusting agent was adjusted according to the pH to be adjusted.

[0063] (Comparative Examples 1-2) By mixing the above-mentioned slurry precursor 3 with a pH adjusting agent (tris(hydroxymethyl)aminomethane) and pure water, slurry B (polishing slurry) containing 0.05% by mass (based on the total mass of slurry B) of abrasive grains containing untreated cerium compound particles was obtained. The content of the pH adjusting agent was adjusted according to the pH to be adjusted.

[0064] <Measurement of Abrasive Grain Size> The abrasive grain sizes D50 and D90 in the above-mentioned slurry B were measured under the following conditions. The grain size D50 was 6.1 nm in Examples 1 to 3, 6.2 nm in Examples 4 to 6, 8.1 nm in Examples 7 to 10, 7.1 nm in Examples 11 to 13, 6.9 nm in Examples 14 to 16, 5.1 nm in Examples 17 to 20, 4.6 nm in Examples 21 to 22, and 6.6 nm in Comparative Examples 1 to 2. The grain size D90 was 10.4 nm in Examples 1 to 3, 10.6 nm in Examples 4 to 6, 12.9 nm in Examples 7 to 10, 11.7 nm in Examples 11 to 13, 11.5 nm in Examples 14 to 16, 9.0 nm in Examples 17 to 20, 8.1 nm in Examples 21 to 22, and 10.9 nm in Comparative Examples 1 to 2. Measurement temperature: 25°C Measurement device: Wyatt Technology Co., Ltd., product name "Mobius" Measurement method: Approximately 4 mL of slurry B was placed in a 1 cm square cell, and then the cell was placed in the measurement device. Measurements were performed under the conditions of laser wavelength 532 nm, measurement temperature 25°C, measurement angle 163.5°, and number of integrations 10 times. The particle size distribution values ​​D50 and D90 were obtained by calculating the scattering intensity converted to mass from the measurement results.

[0065] <Zeta Potential Measurement> The zeta potential of the abrasive grains in slurry B was measured at 25°C using the product name "DT-1202" manufactured by Dispersion Technology. In each of Examples 1 to 22 and Comparative Examples 1 to 2, the zeta potential of the abrasive grains was 20 to 55 mV.

[0066] <pH Measurement> The pH of slurry B was measured under the following conditions. The results are shown in Table 1. Measurement temperature: 25°C Measuring device: Model (D-71) manufactured by Horiba, Ltd. Measurement method: A pH meter was calibrated at three points using phthalate pH standard solution (pH: 4.01), neutral phosphate pH standard solution (pH: 6.86), and borate pH standard solution (pH: 9.18) as pH standard solutions. After that, the electrode of the pH meter was placed in slurry B, and the pH was measured using the above measuring device after it had stabilized for more than 2 minutes.

[0067] <Evaluation of polishing speed> A φ300 mm wafer with a silicon nitride (SiN) film on its surface was prepared as the blanket wafer.

[0068] The wafer was polished using the slurry B described above under the following polishing conditions: Polishing apparatus: F-REX300X (manufactured by Ebara Corporation) Slurry flow rate: 200 mL / min Polishing pad: Foamed polyurethane resin with closed cells (manufactured by Rohm & Haas Japan Co., Ltd., model number: IC1000) Polishing pressure: 14.7 kPa (2 psi) Plate rotation speed: 93 min －１ Head rotation speed: 87 min －１ Polishing time: 30 seconds. Cleaning: After polishing, the wafer was washed with water and then dried with a spin dryer.

[0069] Using an optical interferometry film thickness measuring device (device name: NOVA i500) manufactured by Nova Measuring Instruments, the film thickness of the silicon nitride film on the above wafer before and after polishing was measured at 65 points. The 65 film thickness measurements were taken on a straight line including the center of the wafer, with the wafer center as the reference point, at positions of 149 mm, 148 mm, 147 mm, and 145 mm, at 5 mm intervals between 145 mm and -145 mm (140 mm, 135 mm, ..., -135 mm, -140 mm), and at -145 mm, -147 mm, -148 mm, and -149 mm (with the wafer center as the reference point, distances opposite to positive distances are indicated by negative values). The change in film thickness was calculated using the average value of the 65 film thickness measurements. The polishing speed was calculated based on the change in film thickness and polishing time, and the relative ratio to the polishing speed of silicon nitride in Comparative Example 2 was calculated. Table 1 shows the relative polishing rates of silicon nitride.

[0070]

Claims

1. Abrasive grains for polishing silicon nitride, comprising cerium-based particles, wherein the cerium-based particles are surface-treated with a silane compound.

2. The abrasive grain according to claim 1, wherein the silane compound has a primary amino group.

3. The abrasive grain according to claim 1, wherein the silane compound comprises an aminoalkyltrialkoxysilane.

4. The abrasive grain according to claim 1, wherein the silane compound has a secondary amino group.

5. The abrasive grain according to claim 4, wherein the number of secondary amino groups in the silane compound is 1.

6. The abrasive grain according to claim 4, wherein the number of secondary amino groups in the silane compound is 2.

7. The abrasive grain according to claim 1, wherein the silane compound has a tertiary amino group.

8. The abrasive grain according to claim 1, wherein the silane compound has a heterocycle.

9. The abrasive grain according to claim 8, wherein the heterocycle includes an oxirane ring.

10. The abrasive grain according to claim 8, wherein the heterocycle includes a morpholine ring.

11. The abrasive grain according to claim 1, wherein the silane compound has a urea bond.

12. The abrasive grain according to claim 1, wherein the particle size D50 is less than 10.0 nm.

13. A slurry containing abrasive grains as described in any one of claims 1 to 12.

14. The slurry according to claim 13, wherein the pH is 3.0 to 10.

0.

15. The slurry according to claim 13, wherein the pH is 4.0 to 6.

0.

16. A polishing method comprising the step of polishing a workpiece containing silicon nitride using the slurry described in claim 13.

17. A method for manufacturing a part, comprising the step of obtaining a part using a member to be polished by the polishing method described in claim 16.

18. A method for manufacturing a semiconductor component, comprising the step of obtaining a semiconductor component using a member to be polished by the polishing method described in claim 16.

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