Polishing composition, method for producing the same, polishing method, and method for producing substrate

Abstract

The present invention provides a means to realize a high polishing rate for a specific material, while also realizing a significantly high selectivity ratio and a significantly high step reduction effect between dissimilar materials. The present invention relates to a polishing composition containing silica with an organic acid fixed on its surface and polyalkylene glycol, wherein the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC) regarding the polyalkylene glycol has two or more peaks within a predetermined molecular weight range, at least one of which is a peak derived from polyethylene glycol, and the pH is 3 or higher and 6 or lower.

Description

Technology Field

[0001] The present invention relates to a polishing composition, a method for manufacturing the same, a polishing method, and a method for manufacturing a substrate. Background Technology

[0002] In the semiconductor device manufacturing process, as the performance of semiconductor devices improves, there is a growing need for technology that manufactures wiring with higher density and greater integration. Chemical Mechanical Polishing (CMP) has become an essential process in the manufacturing of such semiconductor devices. As semiconductor circuits become more miniaturized, the required flatness regarding the irregularities of pattern wafers increases, necessitating the realization of nano-order high flatness through CMP. To achieve high smoothness through CMP, it is desirable to polish the convex areas of the pattern wafer at a high polishing speed while minimizing polishing of the concave areas.

[0003] Semiconductor wafers are composed of heterogeneous materials, such as polycrystalline silicon that forms circuits, silicon oxide which is an insulating material, and silicon nitride which protects the surface of silicon dioxide from damage during etching, rather than being part of a trench or via. Because of this, there is a problem in that step heights remain due to phenomena such as dishing, where some materials are excessively removed compared to others, caused by differences in the polishing speed of each material by the polishing composition. In this regard, it is required to sufficiently eliminate step heights during the polishing process of pattern wafers.

[0004] As a technology to meet this requirement, for example, Japanese Patent Publication No. 2012-040671 discloses a polishing composition capable of polishing a polishing target with poor chemical reactivity, such as silicon nitride, at a high speed compared to polycrystalline silicon, etc. Specifically, as such a polishing composition, a polishing composition containing colloidal silica with an immobilized organic acid and having a pH of 6 or less is disclosed.

[0005] In addition, for example, International Publication No. 2016 / 052281 discloses a polishing composition capable of reducing step height by suppressing the polishing speed of polycrystalline silicon or silicon oxide while maintaining or improving the polishing speed of silicon nitride, etc. Specifically, as such a polishing composition, a polishing composition is disclosed that contains silica with an organic acid fixed to its surface and a polyoxyalkylene group-containing compound, wherein the molecular weight distribution of the weight average molecular weight (converted to polyethylene glycol) by gel permeation chromatography (GPC) regarding the polyoxyalkylene group-containing compound has two or more peaks and the pH is 7 or lower. The problem to be solved

[0006] However, in recent years, as the performance required for semiconductor devices and the like improves, further improvement in polishing performance by polishing compositions is expected. For example, polishing compositions are expected to exhibit a higher selectivity ratio between dissimilar materials than the polishing compositions described in Japanese Patent Publication No. 2012-040671 and International Publication No. 2016 / 052281, and to exhibit a higher step reduction effect when polishing a workpiece containing dissimilar materials.

[0007] Therefore, the present invention aims to provide a means capable of realizing a high polishing speed for a specific material, while also realizing a significantly high selectivity ratio and a significantly high step reduction effect between dissimilar materials. means of solving the problem

[0008] The above problem of the present invention can be solved by the following means:

[0009] Silica with organic acids fixed to its surface, and

[0010] polyalkylene glycol

[0011] Contains,

[0012] The molecular weight distribution of the polyethylene glycol equivalent by gel permeation chromatography (GPC) regarding the above polyalkylene glycol has two or more peaks, and

[0013] At least one peak of the above molecular weight distribution is a peak with a peak top molecular weight of 1,000 or more and 6,000 or less, and

[0014] At least one peak of the above molecular weight distribution is a peak with a peak top molecular weight of 100 or more and 800 or less, and

[0015] The above polyalkylene glycol contains polyethylene glycol,

[0016] At least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol, and

[0017] A polishing composition having a pH of 3 or higher and 6 or lower.

[0018] In addition, the above problem of the present invention can also be solved by the following means:

[0019] Silica with organic acids fixed to its surface, and

[0020] polyalkylene glycol

[0021] It has a mixing process for mixing,

[0022] The molecular weight distribution of the polyethylene glycol equivalent by gel permeation chromatography (GPC) regarding the above polyalkylene glycol has two or more peaks, and

[0023] At least one peak of the above molecular weight distribution is a peak with a peak top molecular weight of 1,000 or more and 6,000 or less, and

[0024] At least one peak of the above molecular weight distribution is a peak with a peak top molecular weight of 100 or more and 800 or less, and

[0025] The above polyalkylene glycol contains polyethylene glycol, and at least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol,

[0026] A method for preparing a polishing composition having a pH of 3 or higher and 6 or lower.

[0027] And, the above problem of the present invention can also be solved by the following means:

[0028] Silica with organic acids fixed to its surface, and

[0029] Polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less in the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC), and

[0030] Polyalkylene glycol having a peak top molecular weight of 100 or more and 800 or less in the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC).

[0031] having a mixing process for mixing

[0032] A method for preparing a polishing composition having a pH of 3 or higher and 6 or lower. Specific details for implementing the invention

[0033] Embodiments of the present invention are described below. Furthermore, the present invention is not limited to the following embodiments. Also, in this specification, "X to Y" indicating a range means "X or greater and Y or less." Additionally, unless specifically stated otherwise, operations and measurements of physical properties, etc. are performed under conditions of room temperature (range of 20°C or higher and 25°C or lower) and relative humidity of 40%RH or higher and 50%RH or lower.

[0034] Abrasive composition

[0035] One embodiment of the present invention relates to a polishing composition comprising silica with an organic acid fixed on its surface and polyalkylene glycol, wherein the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC) regarding the polyalkylene glycol has two or more peaks, at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 100 or more and 800 or less, wherein the polyalkylene glycol contains polyethylene glycol, and at least one peak with a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol, and the pH is 3 or more and 6 or less. According to the present embodiment, means can be provided to realize a high polishing rate for a specific material while realizing a significantly high selectivity ratio between dissimilar materials and a significantly high step reduction effect.

[0036] According to such a polishing composition, a means can be provided to realize a high polishing rate for a specific material, while also realizing a significantly high selectivity ratio between dissimilar materials and a significantly high step reduction effect.

[0037] In particular, in one embodiment of the present invention, the effect of the present invention is more pronounced in a polishing object comprising at least one of a material having silicon-nitrogen bonds such as silicon nitride, a material having silicon-oxygen bonds such as silicon oxide, and a material having silicon-silicon bonds such as polycrystalline silicon (polysilicon, Poly-Si). More specifically, the polishing speed of the material having silicon-nitrogen bonds is higher. In one embodiment of the present invention, the ratio of the polishing speed of the material having silicon-nitrogen bonds to the polishing speed of the material having silicon-oxygen bonds (selectivity ratio of the material having silicon-nitrogen bonds to the material having silicon-oxygen bonds) and the ratio of the polishing speed of the material having silicon-nitrogen bonds to the material having silicon-silicon bonds (selectivity ratio of the material having silicon-nitrogen bonds to the material having silicon-silicon bonds) are higher. In one embodiment of the present invention, the step reduction effect of a polishing target comprising a material having silicon-nitrogen bonds such as silicon nitride and a material having silicon-oxygen bonds such as silicon oxide is further enhanced. In one embodiment of the present invention, the step reduction effect of a polishing target comprising a material having silicon-nitrogen bonds such as silicon nitride and a material having silicon-silicon bonds such as polycrystalline silicon is further enhanced.

[0038] Although the detailed reason why the present invention can achieve a high polishing rate for a specific material while realizing a significantly high selectivity ratio and a significantly high step reduction effect between dissimilar materials is unclear, it is presumed to be due to the following mechanism.

[0039] The zeta potential of silica with organic acids immobilized on its surface is negative, and its absolute value also increases. Additionally, some materials included in the object to be polished have a positive zeta potential at pH 6 or lower. Therefore, if the pH of the polishing composition is 6 or lower, the silica with organic acids immobilized on its surface in the polishing composition and the material with a positive zeta potential in this pH range do not repel each other electrically but rather attract each other. Furthermore, silica with organic acids immobilized on its surface possesses functional groups derived from organic acids, which are functional groups other than hydroxyl groups. Since these organic acid-derived functional groups do not interact with polyalkylene glycols, the hydrophilicity inherent to silica becomes more easily exhibited. Moreover, under acidic conditions, because the zeta potential of silica with organic acids immobilized on its surface is high, electrical repulsion occurs between the silicas with organic acids immobilized on their surfaces, thereby improving the dispersion stability of the silica with organic acids immobilized on its surface. In this regard, in a polishing composition with a pH of 6 or lower, by using silica with organic acid fixed to its surface as abrasive particles, a high polishing rate is obtained for materials in which the zeta potential becomes positive in this pH range. In addition, materials in which the zeta potential becomes positive in the pH range of 6 or lower include, for example, materials having silicon-nitrogen bonds such as silicon nitride.

[0040] Furthermore, polyalkylene glycol is adsorbed onto the surface of the object to be polished through actions such as hydrogen bonding. Additionally, polyalkylene glycol acts to protect the surface of the object to be polished from mechanical action by abrasive particles. Here, the ease of adsorption of polyalkylene glycol varies depending on the type of object to be polished. In this regard, by selecting the type of object to be polished, the type of polyalkylene glycol in the polishing composition, and combinations thereof, it becomes possible to control the polishing speed and the selectivity ratio between different materials using the polishing composition. Moreover, by including polyalkylene glycol having a molecular weight distribution with two or more peaks in the polishing composition, the gaps where components with larger molecular weights are adsorbed are further filled by components with smaller molecular weights. As a result, a denser protective film is formed on the surface of the object to be polished, thereby further enhancing the step reduction effect.

[0041] In addition, by setting the pH range of the polishing composition containing silica with an organic acid fixed to its surface and polyalkylene glycol to 3 or higher and 6 or lower, the selectivity ratio between heterogeneous materials regarding a specific combination of materials, for example, the selectivity ratio of a material having a silicon-nitrogen bond to a material having a silicon-oxygen bond, can be significantly improved.

[0042] However, during the investigation, the inventors found that in this pH range, the effect of inhibiting the polishing speed for certain materials, such as silicon-silicon bonds like polycrystalline silicon, is reduced compared to other pH ranges. This indicates that the effect of improving the selectivity ratio between different heterogeneous materials, such as silicon-nitrogen bonds like silicon nitride, compared to silicon-silicon bonds like polycrystalline silicon, is reduced compared to other pH ranges.

[0043] Therefore, the inventors further investigated. As a result, they discovered that the reduction in the suppression effect of the polishing speed for a specific material in this pH range is resolved by polyalkylene glycol containing a specific component and having a specific molecular weight distribution, and thus completed the present invention. That is, the present invention uses a polishing composition containing silica with an organic acid fixed to its surface and polyalkylene glycol containing a specific component and having a specific molecular weight distribution, with a pH range of 3 or higher and 6 or lower. By using such a polishing composition, a significantly high selectivity ratio and a significantly high step reduction effect are obtained between heterogeneous materials in a wide range of combinations. The reason for this is believed to be that within this pH range, the attractive force, repulsive force, adsorption, and desorption are optimized between each material included in the object to be polished and the silica and polyalkylene glycol with the organic acid fixed to its surface in the polishing composition. Furthermore, it is believed that the selectivity ratio and step reduction effect between heterogeneous materials are significantly improved due to this synergistic effect.

[0044] Furthermore, the above mechanism is based on conjecture, and its accuracy does not affect the technical scope of the present invention.

[0045] Below, each component that may be included in the polishing composition, each raw material used in the manufacture of the polishing composition, the physical properties and characteristics of the polishing composition, and the object to be polished will be described.

[0046] (Silica with organic acid fixed to the surface)

[0047] A polishing composition according to one embodiment of the present invention comprises silica with an organic acid fixed to its surface. Furthermore, in a method for manufacturing a polishing composition according to one embodiment of the present invention, silica with an organic acid fixed to its surface is used as a raw material. "Silica with an organic acid fixed to its surface" is silica in which an organic acid is chemically bonded to its surface and used as abrasive particles.

[0048] In the case of silica with an organic acid fixed on its surface, the silica prior to organic acid fixation is not particularly limited, but examples include fumed silica and colloidal silica. Among these, colloidal silica is preferred. Furthermore, in the case of silica with an organic acid fixed on its surface, the method of manufacturing the silica prior to organic acid fixation is not particularly limited. However, from the perspective of enabling production with high purity and further enhancing the effects of the present invention, the method of manufacturing the silica prior to organic acid fixation is preferably the sodium silicate method or the sol-gel method (sol-gel method), and the sol-gel method is more preferred. That is, as for the silica prior to organic acid fixation, it is preferable to use colloidal silica manufactured by the sol-gel method or the sodium silicate method (for example, at least one of colloidal silica manufactured by the sol-gel method and colloidal silica manufactured by the sodium silicate method), and it is more preferable to use colloidal silica manufactured by the sol-gel method.

[0049] In silica with an organic acid fixed to its surface, the organic acid is not particularly limited, but examples include sulfonic acid, carboxylic acid, and phosphoric acid. Among these, it is preferably sulfonic acid or carboxylic acid, and more preferably sulfonic acid. Furthermore, on the surface of the silica with the organic acid fixed to its surface, acidic groups derived from the organic acid (e.g., sulfonate groups, carboxylic acid groups, phosphoric acid groups, etc.) are fixed by covalent bonding (in some cases, through a linker structure).

[0050] Silica with organic acids fixed on its surface may be a synthetic product or a commercially available product. In addition, silica with organic acids fixed on its surface may be used alone or in a mixture of two or more types.

[0051] The method of introducing an organic acid onto the silica surface is not particularly limited, and examples include introducing it onto the silica surface in the form of a mercapto group or an alkyl group, and then oxidizing it to a sulfonic acid or a carboxylic acid. Additionally, examples include introducing it onto the silica surface in the form of a protecting group attached to an acidic group derived from the organic acid, and then removing the protecting group. Furthermore, when introducing an organic acid onto the silica surface, it is preferable that the compound used has at least one functional group capable of becoming an organic acid group, and also includes a functional group used for bonding with a hydroxyl group on the silica surface, a functional group introduced to control hydrophobicity and hydrophilicity, and a functional group introduced to control stereochemical volume expansion.

[0052] As a specific synthesis method for silica with an organic acid immobilized on its surface, if sulfonic acid, a type of organic acid, is immobilized on the surface of silica, it can be carried out, for example, by the method described in “Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem. Commun. 246-247 (2003). Specifically, silica with a sulfonic acid immobilized on its surface can be obtained by coupling a silane coupling agent having a thiol group, such as 3-mercaptopropyltrimethoxysilane, to silica and then oxidizing the thiol group with hydrogen peroxide. Alternatively, if carboxylic acid is immobilized on the surface of silica, it can be carried out, for example, by the method described in “Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel”, Chemistry Letters, 3, 228-229 (2000). Specifically, silica with a carboxylic acid immobilized on its surface can be obtained by coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to silica and then irradiating it with light.

[0053] The average primary particle size of silica with organic acid fixed to its surface in the polishing composition is not particularly limited, but it is preferably 5 nm or larger, more preferably 7 nm or larger, and even more preferably 10 nm or larger. In addition, the average primary particle size of silica with organic acid fixed to its surface in the polishing composition is preferably 50 nm or smaller, more preferably 45 nm or smaller, and even more preferably 40 nm or smaller. Within these ranges, the polishing speed of a specific material by the polishing composition is further improved, and the selectivity ratio between dissimilar materials is further improved. In addition, the step reduction effect is also further improved. Therefore, an example of a preferred average primary particle size of silica with organic acid fixed to its surface is 10 nm or larger and 50 nm or smaller. In addition, the value of the average primary particle size of silica with organic acid fixed to its surface can be calculated based on the specific surface area of ​​silica with organic acid fixed to its surface, for example, measured by the BET method.

[0054] The average secondary particle size of silica with organic acid fixed to its surface in the polishing composition is not particularly limited, but it is preferably 10 nm or larger, more preferably 15 nm or larger, and even more preferably 20 nm or larger. In addition, the average secondary particle size of silica with organic acid fixed to its surface in the polishing composition is not particularly limited, but it is preferably 150 nm or smaller, more preferably 100 nm or smaller, and even more preferably 80 nm or smaller. Within these ranges, the polishing speed of a specific material by the polishing composition is further improved, and the selectivity ratio between dissimilar materials is further improved. In addition, the step reduction effect is also further improved. Therefore, an example of a preferred average secondary particle size of silica with organic acid fixed to its surface is 20 nm or larger and 100 nm or smaller. In addition, the value of the average secondary particle size of silica with organic acid fixed to its surface can be calculated based on, for example, a light scattering method measurement using laser light.

[0055] The degree of aggregation of silica with organic acid fixed to its surface in the polishing composition is not particularly limited, but it is preferably 1 or higher, more preferably 2 or higher, and even more preferably 2.5 or higher. In addition, the degree of aggregation of silica with organic acid fixed to its surface in the polishing composition is preferably 10 or lower, more preferably 8 or lower, and even more preferably 5 or lower. Within this range, the polishing speed of a specific material by the polishing composition is further improved, and the selectivity ratio between dissimilar materials is further improved. In addition, the step reduction effect is also further improved. Furthermore, the degree of aggregation of silica with organic acid fixed to its surface can be calculated by dividing the value of the average secondary particle size by the value of the average primary particle size.

[0056] The zeta potential of silica with an organic acid fixed to its surface in the polishing composition is preferably a negative value, preferably -5 mV or less, more preferably -10 mV or less, and even more preferably -15 mV or less. Within this range, aggregation of silica becomes less likely to occur. Furthermore, the zeta potential of silica with an organic acid fixed to its surface in the polishing composition is preferably -70 mV or more, more preferably -60 mV or more, and even more preferably -50 mV or more. Within this range, adhesion of abrasive particles to the object to be polished becomes less likely to occur. Additionally, the zeta potential of silica with an organic acid fixed to its surface can be specifically measured by the method described in the examples.

[0057] The shapes of the primary and secondary particles of silica with organic acid fixed on the surface are not particularly limited and may be spherical or non-spherical, respectively. Among these, the shape of the secondary particles is preferably cocoon-shaped or a shape in which deformation is more advanced than in cocoon-shaped, such as chain-shaped or branched-shaped, and it is more preferable for them to be cocoon-shaped.

[0058] The content (amount added) of silica with organic acid fixed to its surface in the polishing composition is not particularly limited, but it is preferable that it be 0.001 mass% or more, more preferable that it be 0.01 mass% or more, and even more preferable that it be 0.1 mass% or more. Within this range, the polishing speed of the object to be polished by the polishing composition is further improved. In addition, the content of silica with organic acid fixed to its surface in the polishing composition is preferably 10 mass% or less, more preferable that it be 8 mass% or less, and even more preferable that it be 5 mass% or less. Within this range, polishing of a specific material by the polishing composition is further suppressed, and the selectivity ratio between different materials is further improved.

[0059] In addition, in a polishing composition according to one embodiment of the present invention, it is essential to use silica with an organic acid fixed to its surface as abrasive particles, but in some cases, other abrasive particles, such as silica without an organic acid fixed to its surface, may be used in combination. However, the content ratio of silica with an organic acid fixed to its surface that accounts for the total abrasive particles is not particularly limited, but it is preferable that it be 50 mass% or more by mass, more preferable that it be 80 mass% or more, even more preferable that it be 90 mass% or more, particularly preferable that it be 95 mass% or more, and most preferable that it be 100 mass%.

[0060] (Polyalkylene glycol)

[0061] A polishing composition according to one embodiment of the present invention comprises polyalkylene glycol. In addition, in a method for manufacturing a polishing composition according to one embodiment of the present invention, polyalkylene glycol is used as a raw material.

[0062] It is preferable that the polyalkylene glycol has two or more peaks in its molecular weight distribution in terms of polyethylene glycol equivalent by gel permeation chromatography (GPC). Here, "having two or more peaks" means that the chart of the molecular weight distribution (differential molecular weight distribution curve) of the polyalkylene glycol by GPC has two or more maximum values. Typically, as described in the section on the method for manufacturing a polishing composition to be described later, a polishing composition can be obtained by using two or more types of polyalkylene glycols with different peak top molecular weights in the molecular weight distribution in terms of polyethylene glycol equivalent by GPC, for example, to manufacture the polishing composition. Here, it is preferable that at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 100 or more and 800 or less. And, the above polyalkylene glycol contains polyethylene glycol, and it is preferable that at least one of the peaks with a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol.

[0063] Here, in the molecular weight distribution of polyalkylene glycol converted by GPC, it is preferable that at least one peak with a peak top molecular weight of 100 or more and 800 or less is a peak derived from polyethylene glycol. Furthermore, it is preferable that the polyalkylene glycol further comprises polypropylene glycol or polybutylene glycol, and that at least one peak with a peak top molecular weight of 100 or more and 800 or less is a peak derived from polypropylene glycol or polybutylene glycol. In addition, it is particularly preferable that the polyalkylene glycol included in the polishing composition according to one embodiment of the present invention is only polyethylene glycol, and that all peaks are peaks derived from polyethylene glycol.

[0064] The number of peaks in the molecular weight distribution of polyethylene glycol equivalent by GPC of polyalkylene glycol is not particularly limited as long as it is 2 or more, but it is preferably 2 or 10 or less, more preferably 2 or 3, and even more preferably 3. In addition, the number of peaks with a peak top molecular weight of 1,000 or more and 6,000 or less in the molecular weight distribution of polyalkylene glycol equivalent by GPC is not particularly limited as long as it is 1 or more, but it is preferably 1 or 5 or less, more preferably 1 or 2, and even more preferably 1. Furthermore, the number of peaks with a peak top molecular weight of 100 or more and 800 or less in the molecular weight distribution of polyalkylene glycol equivalent by GPC is not particularly limited as long as it is 1 or more, but it is preferably 1 or 5 or less, more preferably 1 or 2, and even more preferably 2. Within these ranges, the dispersion state of polyethylene glycol becomes better. In addition, more uniform and dense adsorption of the workpiece is possible, enabling better control of step shapes that could not be achieved with a single peak.

[0065] In the molecular weight distribution of polyethylene glycol equivalent by GPC of polyalkylene glycol, at least one peak having a peak top molecular weight of 1,000 or more and 6,000 or less is not particularly limited, but it is preferable that it has a peak top molecular weight of 1,100 or more and 5,000 or less, and more preferable that it has a peak top molecular weight of 1,200 or more and 4,000 or less. Within this range, the selectivity ratio between heterogeneous materials is further improved. In addition, the step difference reduction effect is also further improved. Furthermore, when polyalkylene glycol has multiple peaks having a peak top molecular weight of 1,000 or more and 6,000 or less, it is preferable that all peaks have a peak top molecular weight within the above range. In this case, the selectivity ratio between heterogeneous materials is further improved. In addition, the step difference reduction effect is also further improved.

[0066] In the molecular weight distribution of polyethylene glycol equivalent by GPC of polyalkylene glycol, at least one peak with a peak top molecular weight of 100 or more and 800 or less is not particularly limited, but it is more preferable that it has a peak top molecular weight of 150 or more and 700 or less, and even more preferable that it has a peak top molecular weight of 200 or more and 600 or less. Within this range, the selectivity ratio between dissimilar materials is further improved. In addition, the step difference reduction effect is also further improved. Furthermore, when polyalkylene glycol has multiple peaks with a peak top molecular weight of 100 or more and 800 or less, it is preferable that all peaks are within the above range. In this case, the selectivity ratio between dissimilar materials is further improved. In addition, the step difference reduction effect is also further improved.

[0067] In addition, when two or more types of polyalkylene glycols are used as raw materials, the polyalkylene glycols used as raw materials are not particularly limited, but examples include polyalkylene glycols having a peak top molecular weight in the same range as the preferred range of each of the above peaks.

[0068] In addition, the molecular weight distribution of polyethylene glycol equivalent by GPC for polyalkylene glycol, or the peak top molecular weight, can be specifically measured by the method described in the examples. Furthermore, the number average molecular weight and weight average molecular weight can also be measured by the same method.

[0069] The polyalkylene glycol included in the polishing composition may be a commercially available product or a synthetic product. In addition, the polyalkylene glycol included in the polishing composition may be composed of a single type of polyalkylene glycol or two or more types of polyalkylene glycols. Among these, it is preferable that the polyalkylene glycol be composed of a single type of polyalkylene glycol.

[0070] The types of polyalkylene glycols are not particularly limited, but examples include polyalkylene glycols such as at least two copolymers selected from the group consisting of polyethylene glycol, polypropylene glycol, polybutylene glycol, and ethylene glycol, propylene glycol, and glycol. Among these, polyethylene glycol and polypropylene glycol are preferred, and polyethylene glycol is more preferred.

[0071] In addition, when two or more types of polyalkylene glycols are used as raw materials, the polyalkylene glycols used as raw materials are not particularly limited, but examples include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol. As commercially available products, examples include polyethylene glycol 200, 600, 1,000, 1,540, 2,000, 4,000, 6,000, 8,000, and 20,000 (manufactured by Fujifilm Wako Junyaku Co., Ltd.), Polyethylene glycol 10,000 (manufactured by Alfa Aesar), and polypropylene glycol, diol type, 400 (manufactured by Fujifilm Wako Junyaku Co., Ltd.). In addition, examples include block polymers represented by the Pronon (registered trademark) series, such as Pronon (registered trademark) 102 and Pronon (registered trademark) 201 (manufactured by Nichiyu Kabushiki Kaisha). Among these, polyethylene glycol and polypropylene glycol are preferred, and polyethylene glycol is more preferred.

[0072] The content (amount added) of polyalkylene glycol in the polishing composition is not particularly limited, but it is preferable that it be 0.001 g / L or more, more preferable that it be 0.01 g / L or more, and even more preferable that it be 0.1 g / L or more. In addition, the content of polyalkylene glycol in the polishing composition is preferably 100 g / L or less, more preferable that it be 10 g / L or less, and even more preferable that it be 5 g / L or less. Within these ranges, the selectivity ratio between dissimilar materials is further improved. In addition, the step difference reduction effect is also further improved.

[0073] In the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC) as a raw material, when polyethylene glycol with a peak top molecular weight of 1,000 or more and 6,000 or less and polyalkylene glycol with a peak top molecular weight of 100 or more and 800 or less are used, the ratio of the amount of polyethylene glycol with a peak top molecular weight of 1,000 or more and 6,000 or less to the total amount of these added is not particularly limited, but it is preferable that it be 10 mass% or more, more preferable that it be 20 mass% or more, even more preferable that it be 40 mass% or more, even more preferable that it be 70 mass% or more, and particularly preferable that it be 75 mass% or more. In addition, the ratio of the amount of polyethylene glycol with a peak top molecular weight of 1,000 or more and 6,000 or less to the total amount of these added is preferably 90 mass% or less, more preferably 85 mass% or less, and even more preferably 80 mass% or less.

[0074] (Abrasive accelerator)

[0075] A polishing composition according to one embodiment of the present invention preferably includes a polishing accelerator. In addition, in a method for manufacturing a polishing composition according to one embodiment of the present invention, it is preferable to use a polishing accelerator as a raw material. The polishing accelerator acts to improve the polishing speed of a specific material by the polishing composition. As a result, the selectivity ratio between dissimilar materials is further improved.

[0076] As for the polishing accelerator, there are no particular limitations, but it is preferable that it be a compound capable of improving the polishing speed of a material having a positive zeta potential at the pH of the polishing composition (a polishing accelerator for a material having a positive zeta potential). Furthermore, it is more preferable that it be a compound capable of improving the polishing speed of a material having a silicon-nitrogen bond, such as silicon nitride (a polishing accelerator for a material having a silicon-nitrogen bond, preferably a polishing accelerator for silicon nitride). Such a compound can achieve a higher polishing speed and a higher selectivity ratio when using silica with an organic acid having a negative zeta potential fixed on its surface, even when the absolute value of the positive zeta potential of the material to be polished is small.

[0077] Examples of polishing promoters for materials having silicon-nitrogen bonds, such as silicon nitride, are not particularly limited but include N-methyl-D-glucamine, D-glucamine, N-ethyl-D-glucamine, N-propyl-D-glucamine, N-octyl-D-glucamine, N-acetyl-D-glucosamine, tris(hydroxymethyl)aminomethane, bis(2-hydroxyethyl)aminotris(hydroxymethyl)methane, N-(2-acetamide)imino-2-acetic acid, N,N-di(2-hydroxyethyl)glycine, N-[tris(hydroxymethyl)methyl]glycine, hydroxyethylimino-2-acetic acid, imino-2-acetic acid, hydroxyethylidenediphosphonic acid (HEDP), nitrilotrismethylenephosphonic acid, phosphonobutanetricarboxylic acid, and salts thereof. In addition, alkanolamines, amino acids, and their salts may be used. Among these, N-methyl-D-glucarmine is preferred.

[0078] Abrasive accelerators may be synthetic or commercially available. Additionally, abrasive accelerators may be used alone or in combination of two or more types.

[0079] The content (amount added) of the polishing accelerator in the polishing composition is not particularly limited, but it is preferable that it be 0.01 g / L or more, more preferable that it be 0.1 g / L or more, and even more preferable that it be 1 g / L or more. Within this range, the effect of improving the polishing speed of a specific material by the polishing accelerator is higher. In addition, the content of the polishing accelerator in the polishing composition is preferably 100 g / L or less, more preferable that it be 50 g / L or less, and even more preferable that it be 10 g / L or less. Within this range, the possibility of reprecipitation of the polishing accelerator can be further reduced. In addition, the possibility of deterioration of the polishing composition due to the reaction between the polishing accelerator and other additives can be further reduced.

[0080] (Standard Improver)

[0081] A polishing composition according to one embodiment of the present invention preferably includes a step modifier. In addition, in a method for manufacturing a polishing composition according to one embodiment of the present invention, it is preferable to use a step modifier as a raw material. The step modifier acts to reduce unintended step differences occurring between heterogeneous materials regarding a combination of specific materials, or unintended step differences occurring between dense parts of a pattern.

[0082] As a step improvement agent, it is not particularly limited, but it is preferable to have a compound capable of further enhancing the step reduction effect of a polishing target including a material having silicon-nitrogen bonds such as silicon nitride and a material having silicon-oxygen bonds such as silicon oxide (preferably, a step improvement agent of a material having silicon-nitride bonds and a material having silicon-oxygen bonds, more preferably, a step improvement agent of silicon nitride and silicon oxide). In addition, it is preferable to have a compound capable of further enhancing the step reduction effect of a polishing target including a material having silicon-nitride bonds such as silicon nitride and a material having silicon-silicon bonds such as polycrystalline silicon (preferably, a step improvement agent of a material having silicon-nitride bonds and a material having silicon-silicon bonds, more preferably, a step improvement agent of silicon nitride and polycrystalline silicon).

[0083] As a step improvement agent for materials having silicon-nitrogen bonds such as silicon nitride and materials having silicon-oxygen bonds such as silicon oxide, or for materials having silicon-silicon bonds such as silicon nitride and materials having silicon-silicon bonds such as polycrystalline silicon, preferred examples include an aromatic ring, a compound having a sulfonate group that is directly bonded to said aromatic ring, and a salt thereof, although there are no particular limitations. As for the aromatic ring, it may be an aromatic hydrocarbon ring, an aromatic heterocyclic ring, a monocyclic ring, or a ring formed by the condensation of two or more rings. More specifically, it is preferred to be at least one selected from the group consisting of, for example, a compound represented by the following chemical formula (1) and its salt, a compound represented by the following chemical formula (2) and its salt, and a (co)polymer comprising a structural unit represented by the following chemical formula (3) and its salt. That is, it is preferable that at least one is selected from the group consisting of a compound represented by the following chemical formula (1), a compound represented by the following chemical formula (2), a (co)polymer containing a structural unit represented by the following chemical formula (3), and salts thereof. In addition, the term (co)polymer refers to a general term including copolymers and homopolymers.

[0084] [Chemical Formula 1]

[0085]

[0086] In the above chemical formula (1), R 1 to R 6 Each is independently a hydrogen atom, a hydroxyl group, a sulfone group, an anionic group not containing a sulfone group, a cationic group, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms, wherein R 1 to R 6 At least one of them is a drinking spree.

[0087] [Chemical Formula 2]

[0088]

[0089] In the above chemical formula (2), R 7 to R 14 Each is independently a hydrogen atom, a hydroxyl group, a sulfone group, an anionic group not containing a sulfone group, a cationic group, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms, wherein R 7 to R 14 At least one of them is a drinking spree.

[0090] [Chemical Formula 3]

[0091]

[0092] In the above chemical formula (3), R 15 to R 19 Each is independently a hydrogen atom, a hydroxyl group, a sulfone group, an anionic group not containing a sulfone group, a cationic group, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms, wherein R 15 to R 19 At least one of them is a drinking spree, and R 20 to R 22 Each is a hydrocarbon group having 1 to 10 carbon atoms that is independently substituted with or unsubstituted with a hydrogen atom, a hydroxyl group, an anionic group that does not contain a sulfonate group, a cationic group, an alkoxycarbonyl group having 2 to 6 carbon atoms, or an anionic group that does not contain a hydroxyl group, a cationic group, or an alkoxycarbonyl group having 2 to 6 carbon atoms.

[0093] In addition, in the above chemical formulas (1) to (3), an anionic group refers to a functional group in which a counter ion dissociates to become an anion. In addition, in the above chemical formulas (1) to (3), a cationic group refers to a functional group in which a counter ion dissociates or combines with a cationic species formed by the ionization of another ionic compound to become a cation. As for the cationic group, examples include amino groups, etc.

[0094] In addition, in the above chemical formulas (1) to (3), the amino group represents a -NH2 group, a -NHR group, or a -NRR' group (R and R' represent substituents). In addition, in the above chemical formulas (1) to (3), the alkoxycarbonyl group having 2 to 6 carbon atoms is not particularly limited, but preferred examples include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyloxycarbonyl group, an isopropyloxycarbonyl group, an n-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert-butoxycarbonyl group, etc. Also, in the above chemical formulas (1) to (3), the hydrocarbon group having 1 to 10 carbon atoms is not particularly limited, but preferred examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, etc.

[0095] In addition, the copolymer or its salt containing the structural unit represented by the above chemical formula (3) may further contain structural units derived from other monomers. The structural units derived from other monomers in the copolymer or its salt containing the structural unit represented by the above chemical formula (3) are not particularly limited, but preferred examples include constituent units derived from ethylenically unsaturated monomers, diamines, or diepoxides. In addition, the weight average molecular weight of the (co)polymer or its salt containing the structural unit represented by the above chemical formula (3) is not particularly limited, but is preferably 1,000 or more. Furthermore, the weight average molecular weight of the (co)polymer or its salt containing the structural unit represented by the above chemical formula (3) is preferably 1,000,000 or less. In addition, the weight average molecular weight of the (co)polymer or its salt containing the structural unit represented by the above chemical formula (3) can be obtained as a polystyrene equivalent value measured by GPC.

[0096] Among these, in terms of the step reduction effect of a polishing target including a material having silicon-nitrogen bonds such as silicon nitride and a material having silicon-oxygen bonds such as silicon oxide, and the step reduction effect of a polishing target including a material having silicon-nitrogen bonds such as silicon nitride and a material having silicon-silicon bonds such as polycrystalline silicon, a compound represented by the above chemical formula (1) or a salt thereof is preferred as a step reduction agent. In addition, the compound represented by the above chemical formula (1) or a salt thereof, wherein R in the above chemical formula (1) 1 This is giving up alcohol, and R 2 to R 6 Preferably, the compound or its salt is each independently containing a hydrogen atom, a hydroxyl group, an anionic group that does not contain a sulfonate group, a cationic group, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms. And, the compound or its salt represented by the above formula (1) is, in the above formula (1), R 1 This is giving up alcohol, and R 2 to R 6 It is more preferable that each is a compound or a salt thereof that is independently a hydrogen atom, an -NH2 group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group. Additionally, the compound or salt thereof represented by the above formula (1) is, in the above formula (1), R 1 This is giving up alcohol, and R 2 to R 6 It is more preferable that each be a compound that is independently a hydrogen atom or a methyl group, or a salt thereof.

[0097] In addition, regarding the step reduction effect of a polishing target including a material having silicon-nitrogen bonds such as silicon nitride and a material having silicon-oxygen bonds such as silicon oxide, and the step reduction effect of a polishing target including a material having silicon-nitrogen bonds such as silicon nitride and a material having silicon-silicon bonds such as polycrystalline silicon, specific examples of preferred step reduction agents are not particularly limited, but may include m-xylenesulfonic acid or its salt, p-toluidine-2-sulfonic acid or its salt, 2-naphthol-6-sulfonic acid or its salt, 1-naphthalenesulfonic acid or its salt, parastyrenesulfonic acid-styrene copolymer or its salt, etc. Accordingly, specific examples of desirable step reduction agents are not particularly limited, but may include m-xylenesulfonic acid, p-toluidine-2-sulfonic acid, 2-naphthol-6-sulfonic acid, 1-naphthalenesulfonic acid, parastyrenesulfonic acid-styrene copolymer, and salts thereof. Among these, m-xylenesulfonic acid or its salt, p-toluidine-2-sulfonic acid or its salt, which are compounds represented by the above chemical formula (1) or salts thereof, are more preferred, m-xylenesulfonic acid or its salts are even more preferred, and m-xylenesulfonic acid is particularly preferred. Accordingly, more preferred embodiments include m-xylenesulfonic acid, p-toluidine-2-sulfonic acid and salts thereof, more preferred embodiments include m-xylenesulfonic acid and salts thereof, and particularly preferred embodiments include m-xylenesulfonic acid.

[0098] In addition, if the step modifier is a salt, the sulfate group, or some or all of other functional groups capable of forming a salt, may be a salt.

[0099] Composite step modifiers may be used, or commercially available products may be used. Additionally, step modifiers may be used alone or in combination of two or more types.

[0100] The content (amount added) of the step modifier in the polishing composition is not particularly limited, but it is preferable that it be 0.01 g / L or more, more preferable that it be 0.1 g / L or more, and even more preferable that it be 1 g / L or more. Within this range, the effect of reducing unintended steps occurring between dissimilar materials regarding a specific material combination, or unintended steps occurring between dense parts of a pattern, is further enhanced. In addition, the content of the step modifier in the polishing composition is preferably 100 g / L or less, more preferable that it be 50 g / L or less, and even more preferable that it be 10 g / L or less. Within this range, the possibility of reprecipitation of the step modifier can be further reduced. Furthermore, the possibility of deterioration of the polishing composition due to the reaction between the step modifier and other additives can be further reduced.

[0101] When mixing the step improvement agent during the preparation of the polishing composition, it may be in the state of the step improvement agent itself or in the state of its hydrate. In addition, when mixing the step improvement agent in the state of its hydrate, the content of the step improvement agent in the polishing composition shall be expressed as the content calculated from the mass excluding the hydrated water.

[0102] (pH adjuster)

[0103] A polishing composition according to one embodiment of the present invention preferably includes a pH adjusting agent. In addition, in a method for manufacturing a polishing composition according to one embodiment of the present invention, it is preferable to use a pH adjusting agent as a raw material. The pH adjusting agent acts to adjust the pH of the polishing composition to a desired value by adding an appropriate amount to the polishing composition.

[0104] As a pH adjuster, any known pH adjuster used in the field of abrasive compositions may be used without particular limitation. Among these, it is preferable to use known acids, bases, salts thereof, etc.

[0105] The acid used as a pH adjuster is not particularly limited and may be an inorganic or an organic acid. As for inorganic acids, there are no particular limitations, but examples include carbonic acid, hydrochloric acid, nitric acid, phosphoric acid, hypophosphorous acid, phosphoric acid, phosphonic acid, sulfuric acid, boric acid, hydrofluoric acid, orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, metaphosphoric acid, hexametaphosphoric acid, etc. Among these, nitric acid is preferred.

[0106] Examples of organic acids include carboxylic acids, organic phosphorus-based acids having a phosphonic acid or phosphate group, and sulfonic acids. Among these, it is preferable that it be a carboxylic acid.

[0107] In addition, as an organic acid, it may be an organic acid having only one organic acid group in the molecule, or an organic acid having two or more organic acid groups in the molecule. As for an organic acid having only one organic acid group in the molecule, it is not particularly limited, but it is preferable to have at least one organic acid group selected from the group consisting of, for example, a carboxyl group, a phosphonic acid group or a phosphate group and a sulfonate group (sulfonic acid group). Specifically, examples include monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, hydroxyisobutyric acid, salicylic acid, and lactic acid, monosulfonic acids such as methanesulfonic acid, ethanesulfonic acid, and isethionic acid, and monovalent organic phosphorus-based acids. In addition, the organic acid having two or more organic acid groups in the molecule is not particularly limited, but it is preferable to have at least one organic acid group selected from the group consisting of, for example, a carboxyl group, a phosphonic acid group, a phosphate group, and a sulfonyl group (sulfonic acid group) in the molecule. Specific examples are not particularly limited, but include polycarboxylic acids such as succinic acid, adipic acid, glutaric acid, pimetic acid, phthalic acid, isophthalic acid, terephthalic acid, oxalic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, 2-penteneic acid, methylene succinic acid, allyl malonic acid, isopropylidene succinic acid, 2,4-hexadienoic acid, acetylene dicarboxylic acid, citric acid, malic acid, tartaric acid, aconitic acid, itaconic acid, and melic acid, polysulfonic acids, phytic acid, and polyvalent organic phosphorus-based acids such as hydroxyethylidene diphosphonic acid.

[0108] Specific examples of bases are not particularly limited, but include, for example, hydroxides of alkali metals such as potassium hydroxide, ammonia, quaternary ammonium salts such as tetramethylammonium and tetraethylammonium, and amines such as ethylenediamine and piperazine.

[0109] Among these, it is preferable that it be an acid, more preferable that it be an acid having two or more acidic groups in the molecule, and even more preferable that it be an organic acid having two or more organic acid groups in the molecule. Furthermore, it is even more preferable that it be a polycarboxylic acid, particularly preferable that it be an aliphatic polycarboxylic acid, and particularly preferable that it be an unsaturated aliphatic polycarboxylic acid. Moreover, it is highly preferable that it be an unsaturated aliphatic dicarboxylic acid, and most preferable that it be maleic acid.

[0110] The content (amount added) of the pH adjuster in the polishing composition is not particularly limited as long as the amount makes the pH of the polishing composition 3 or higher and 6 or lower, but it is preferable to add an amount that makes the polishing composition described below have a desirable pH value.

[0111] (Dispersed)

[0112] A polishing composition according to one embodiment of the present invention preferably comprises a dispersion medium. Furthermore, in a method for manufacturing a polishing composition according to one embodiment of the present invention, it is preferable to use a dispersion medium as a raw material. The dispersion medium acts to disperse or dissolve each component.

[0113] The dispersion medium is not particularly limited, but may include water or organic solvents. As for the organic solvent, any known organic solvent may be used without particular limitation. Among these, it is preferable for the dispersion medium to include water, and it is more preferable for it to consist solely of water. Furthermore, from the perspective of preventing impurities from affecting other components of the polishing composition, it is preferable to use water of the highest possible purity. Specifically, pure water, ultrapure water, or distilled water is preferred, which has been purified by removing impurity ions with an ion exchange resin and then passing through a filter to remove foreign substances. Additionally, as a dispersion medium, for the purpose of controlling the dispersibility of other components of the polishing composition, organic solvents that are miscible with water, such as acetone, acetonitrile, methanol, ethanol, isopropanol, glycerin, ethylene glycol, and propylene glycol, may be added in addition to water. When using an organic solvent that is miscible with water in addition to water, the water and the organic solvent may be mixed, and each component may be added to the resulting mixed solvent to disperse or dissolve. In addition, these organic solvents may be used without mixing with water, and then mixed with water after dispersing or dissolving each component. Such water-miscible organic solvents may be used alone or in combination of two or more types.

[0114] (Other ingredients)

[0115] The polishing composition according to one embodiment of the present invention may additionally include other known components used in the field of polishing compositions, if necessary. Furthermore, in the method for manufacturing the polishing composition according to one embodiment of the present invention, other known components used in the field of polishing compositions may additionally be used as raw materials, if necessary. Other components are not particularly limited, but examples may include chemistry agents, metal corrosion inhibitors, preservatives, antifungal agents, oxidizing agents, reducing agents, electrical conductivity modifiers, and water-soluble polymers other than the components described above. Among these, it is preferable to include a preservative or an antifungal agent.

[0116] As preservatives or antifungal agents, known preservatives or known antifungal agents used in the field of abrasive compositions may be used, without particular limitation. Specifically, examples include isothiazoline-based preservatives such as 2-methyl-4-isothiazolin-3-one or 5-chloro-2-methyl-4-isothiazolin-3-one, parahydroxybenzoic acid esters, phenoxyethanol, etc.

[0117] (pH of the abrasive composition)

[0118] In one embodiment of the present invention, the pH of the polishing composition is 3 or higher and 6 or lower. If the pH value is greater than 6, the absolute value of the positive zeta potential of the material with a positive zeta potential becomes smaller; therefore, when using silica with an organic acid with a negative zeta potential fixed to its surface, it becomes difficult to polish at a high polishing speed. Furthermore, as a result, the selectivity between dissimilar materials containing such materials is reduced. Additionally, it is preferable that the pH of the polishing composition be 5.5 or lower, and more preferable that it be 5 or lower. Within this range, it is possible to polish the material with a positive zeta potential using the polishing composition at a sufficient polishing speed, while obtaining a higher selectivity and a higher step reduction effect between dissimilar materials in a wide combination including this. On the other hand, if the pH value is less than 3, the selectivity between dissimilar materials is reduced. For example, if a material having silicon-oxygen bonds, such as silicon oxide, is present in the vicinity of a material having silicon-nitrogen bonds, such as silicon nitride, on a workpiece, it becomes impossible to sufficiently secure the selectivity ratio of the material having silicon-nitrogen bonds to the material having silicon-oxygen bonds. It is preferable that the pH of the polishing composition be 3.5 or higher, and more preferable that it be 4.5 or higher. Within this range, a higher selectivity ratio and a higher step reduction effect can be obtained between heterogeneous materials in a wide combination including materials with a positive zeta potential. Furthermore, the pH of the polishing composition can be measured by the method described in the examples. Additionally, the pH of the polishing composition can be adjusted, for example, by the amount of a pH adjuster added.

[0119] (Type of abrasive composition)

[0120] The polishing composition according to one embodiment of the present invention, or the polishing composition prepared by the method for preparing the polishing composition according to one embodiment of the present invention, may be a single-component type or a multi-component type including a two-component type. In the case of a multi-component type, the polishing composition according to one embodiment of the present invention, or the polishing composition prepared by the method for preparing the polishing composition according to one embodiment of the present invention, may be one of the liquids, two or more liquids, or all liquids. Furthermore, the polishing composition according to one embodiment of the present invention, or the polishing composition prepared by the method for preparing the polishing composition according to one embodiment of the present invention, may be adjusted by diluting the original solution of the polishing composition with a diluent such as water, for example, by 10 times or more.

[0121] (Object to be polished)

[0122] The polishing composition according to one embodiment of the present invention, the polishing composition produced by the manufacturing method according to another embodiment of the present invention described below, the polishing method according to another embodiment of the present invention described below, and the manufacturing method of a substrate according to yet another embodiment of the present invention described below are not particularly limited and can be applied to known polishing objects used in the CMP field. Examples of polishing objects include, for instance, a polishing object comprising a metal, a material having a silicon-nitrogen bond, and other silicon-containing materials.

[0123] It is preferable that the workpiece to be polished comprises two or more types of materials, and it is more preferable that the workpiece to be polished comprises (a) a material having a silicon-nitrogen bond and (b) other silicon-containing materials.

[0124] (a) Material having silicon-nitrogen bonds

[0125] Materials having silicon-nitrogen bonds are not particularly limited, but examples include silicon nitride (SiN) and silicon carbonitride (SiCN).

[0126] (b) Other silicon-containing materials

[0127] Other silicon-containing materials are not particularly limited as long as they are silicon-containing materials other than the silicon-nitrogen bonding material mentioned above, but examples include the following.

[0128] (b-1) Materials having silicon-oxygen bonds

[0129] Materials having silicon-oxygen bonds are not particularly limited, but examples include silicon oxide, BD (black diamond: SiOCH), FSG (fluorosilicate glass), HSQ (hydrogen silsesquioxane), CYCLOTENE, SiLK, MSQ (methyl silsesquioxane), etc. Among these, silicon oxide is preferred. Furthermore, silicon oxide is not particularly limited, but silicon oxide derived from tetraethyl orthosilicate (TEOS) (also referred to simply as "TEOS-SiO" in this specification) is particularly preferred.

[0130] (b-2) Materials having silicon-silicon bonds

[0131] The polishing target having silicon-silicon bonds is not particularly limited, but examples include polycrystalline silicon (polysilicon, Poly-Si), amorphous silicon, single-crystal silicon, n-type doped single-crystal silicon, p-type doped single-crystal silicon, Si-based alloys such as SiGe, etc. Among these, polycrystalline silicon is preferred.

[0132] Accordingly, the polishing composition according to one embodiment of the present invention, the polishing composition manufactured by the manufacturing method according to another embodiment of the present invention described below, the polishing method according to another embodiment of the present invention described below, and the manufacturing method of a substrate according to yet another embodiment of the present invention described below are preferably used for polishing a polishing object comprising (a) a material having silicon-nitrogen bonds and (b) other silicon-containing materials.

[0133] Furthermore, it is more preferable that these polishing compositions be used for polishing a workpiece comprising (a) a material having silicon-nitrogen bonds, (b-1) a material having silicon-oxygen bonds, or (b-2) a material having silicon-silicon bonds. In addition, it is more preferable that these polishing compositions be used for polishing a workpiece comprising silicon nitride, silicon oxide (e.g., TEOS-SiO, etc.), or polycrystalline silicon. Accordingly, it is more preferable that these polishing compositions be used for polishing a workpiece comprising at least one of (a) a material having silicon-nitrogen bonds, (b-1) a material having silicon-oxygen bonds, and (b-2) a material having silicon-silicon bonds. In addition, it is more preferable that these polishing compositions be used for polishing a workpiece comprising at least one of silicon nitride, silicon oxide (e.g., TEOS-SiO, etc.), and polycrystalline silicon.

[0134] In addition, it is more preferable that these polishing compositions be used for polishing objects comprising (a) a material having silicon-nitrogen bonds, (b-1) a material having silicon-oxygen bonds, and (b-2) a material having silicon-silicon bonds. Furthermore, it is even more preferable that these polishing compositions be used for polishing objects comprising silicon nitride, silicon oxide (e.g., TEOS-SiO, etc.), and polycrystalline silicon.

[0135] By applying these polishing compositions to the polishing target as described above, it is possible to achieve a higher polishing speed for specific materials, while also realizing a higher selectivity ratio and a higher step reduction effect between dissimilar materials.

[0136] In addition, the object to be polished, comprising (a) a material having silicon-nitrogen bonds and (b) other silicon-containing materials, may include other materials as needed. Other materials are not particularly limited, but examples include metals. Metals are not particularly limited, but examples include copper, aluminum, hafnium, cobalt, nickel, titanium, tungsten, etc.

[0137] In addition, the object to be polished is preferably a substrate in the form of a product.

[0138] Method for manufacturing a polishing composition

[0139] Another aspect of the present invention relates to a method for preparing a polishing composition having a pH of 3 or higher and 6 or lower, wherein the mixing process involves mixing silica with an organic acid fixed on its surface with polyalkylene glycol, and the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC) regarding the polyalkylene glycol has two or more peaks, at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 1,000 or higher and 6,000 or lower, and at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 100 or higher and 800 or lower, and the polyalkylene glycol contains polyethylene glycol, and at least one of the peaks with a peak top molecular weight of 1,000 or higher and 6,000 or lower is a peak derived from polyethylene glycol. According to the present embodiment, a means can be provided to realize a high polishing speed for a specific material, while also realizing a significantly high selectivity ratio and a significantly high step reduction effect between dissimilar materials.

[0140] In addition, another aspect of the present invention relates to a method for preparing a polishing composition having a pH of 3 or higher and 6 or lower, comprising a mixing process of mixing silica with an organic acid fixed on its surface, polyethylene glycol having a peak top molecular weight of 1,000 or higher and 6,000 or lower in the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC), and polyalkylene glycol having a peak top molecular weight of 100 or higher and 800 or lower in the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC). Furthermore, the manufacturing method according to the present aspect may also be a preferred embodiment of the manufacturing method according to the above aspect. According to the present aspect, means can be provided to realize a high polishing speed for a specific material while realizing a significantly high selectivity ratio and a significantly high step difference reduction effect between dissimilar materials.

[0141] In these embodiments, the details regarding the raw materials, physical properties, and characteristics of the polishing composition being manufactured, or the polishing object to which the polishing composition is applied, are also the same as the description of the polishing composition.

[0142] In addition, the manufacturing method according to these embodiments may also be considered a preferred example of a manufacturing method for producing the polishing composition. Accordingly, the polishing composition produced by the manufacturing method according to these embodiments preferably contains silica with an organic acid fixed on its surface and polyalkylene glycol, wherein the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC) regarding the polyalkylene glycol has two or more peaks, at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 100 or more and 800 or less, wherein the polyalkylene glycol contains polyethylene glycol, and at least one peak with a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol, and the pH is 3 or more and 6 or less. In this case, details such as the polishing composition being manufactured, each component included therein, and the object to be polished to which it is applied are also the same as those described for the polishing composition.

[0143] The mixing process preferably includes mixing silica with an organic acid fixed on its surface and two or more types of polyalkylene glycols with different peak top molecular weights in the molecular weight distribution converted to polyethylene glycol by gel permeation chromatography (GPC). Accordingly, when mixing silica with an organic acid fixed on its surface and polyalkylene glycols in which at least one peak of the molecular weight distribution has a peak top molecular weight of 1,000 or more and 6,000 or less, and at least one peak of the molecular weight distribution has a peak top molecular weight of 100 or more and 800 or less, the mixing process preferably includes mixing polyalkylene glycols in which at least one peak of the molecular weight distribution has a peak top molecular weight of 1,000 or more and 6,000 or less, and polyalkylene glycols in which at least one peak of the molecular weight distribution has a peak top molecular weight of 100 or more and 800 or less. In addition, in this case, the mixing process preferably comprises mixing polyethylene glycol, in which at least one peak of the molecular weight distribution has a peak top molecular weight of 1,000 or more and 6,000 or less, and polyalkylene glycol, in which at least one peak of the molecular weight distribution has a peak top molecular weight of 100 or more and 800 or less.

[0144] In the mixing process, the polishing accelerator, the step improvement agent, the pH adjuster, the dispersion medium, or other components may be further mixed as needed.

[0145] The temperature at which each component is mixed is not particularly limited, but 10 to 40°C is preferred, and heating may be used to increase the dissolution rate.

[0146] In addition, a polishing composition according to one embodiment of the present invention may be adjusted by preparing a stock solution of the polishing composition by the method described above and then diluting the stock solution using a diluent such as water (e.g., diluting by 10 times or more).

[0147] <Polishing Method>

[0148] Another aspect of the present invention relates to a polishing method in which a polishing composition is prepared using the polishing composition or by the manufacturing method described above, and a polishing object is polished using the polishing composition.

[0149] The present embodiment may also be described as an example of a polishing method using the polishing composition or the polishing composition manufactured by the above manufacturing method. In this regard, details regarding the polishing composition, each component included therein, and the polishing object to which it is applied are also the same as those described for the polishing composition. Furthermore, details regarding the raw materials, physical properties, and characteristics of the polishing composition being manufactured, and details regarding the polishing object to which the polishing composition is manufactured are also the same as those described for the polishing composition or the manufacturing method of the polishing composition. Accordingly, as an example of a preferred embodiment, as described above, a polishing method in which the polishing object comprises a material having silicon-nitrogen bonds and other silicon-containing materials; a polishing method in which the polishing object comprises a material having silicon-nitrogen bonds and a material having silicon-oxygen bonds or a material having silicon-silicon bonds; Examples of polishing methods include: a polishing method in which the polishing target comprises at least one of a material having silicon-nitrogen bonds, a material having silicon-oxygen bonds, and a material having silicon-silicon bonds; a polishing method in which the polishing target comprises a material having silicon-nitrogen bonds, a material having silicon-oxygen bonds, and a material having silicon-silicon bonds; a polishing method in which the polishing target comprises silicon nitride and silicon oxide (e.g., TEOS-SiO, etc.), or polycrystalline silicon; a polishing method in which the polishing target comprises silicon nitride, silicon oxide (e.g., TEOS-SiO, etc.), and polycrystalline silicon; and the like. From this, a polishing method according to one embodiment of the present invention can be preferably used for polishing a pattern wafer such as a polysilicon pattern wafer.

[0150] In one embodiment of the present invention, when polishing an object to be polished using a polishing composition, the process may be carried out using devices or conditions used for conventional polishing. Common polishing devices include single-sided polishing devices and double-sided polishing devices. In a single-sided polishing device, a substrate is held and supported using a holding support called a carrier, and while supplying a polishing composition from above, a polishing plate with a polishing pad attached to the opposite side of the substrate is pressed and rotated to polish one side of the material to be polished (object to be polished). At this time, polishing occurs through physical action caused by friction between the polishing pad, the polishing composition, and the object to be polished, and chemical action caused by the polishing composition on the object to be polished. As the polishing pad, porous materials such as non-woven fabric, polyurethane, and suede may be used without particular limitation. It is preferable that the polishing pad be processed to allow the polishing liquid to accumulate.

[0151] Polishing conditions include the polishing load, platen rotation speed, carrier rotation speed, flow rate of the polishing composition, and polishing time. Although there are no specific restrictions on these polishing conditions, for example, regarding the polishing load, it is preferable that it be 0.1 psi or more and 10 psi or less per unit area of ​​the substrate (0.7 to 68.9 kPa, and 1 psi = 6894.76 Pa; the same applies hereinafter), more preferably 0.5 psi or more and 8 psi or less (3.4 to 55.1 kPa), and even more preferably 1 psi or more and 6 psi or less (6.9 to 41.4 kPa). Generally, as the load increases, the frictional force generated by the abrasive grains increases and the mechanical processing power improves, so the polishing speed increases. Within this range, a higher polishing speed can be achieved, which can further suppress substrate breakage caused by the load or the occurrence of defects such as scratches on the surface. The platen rotation speed and carrier rotation speed are 10 to 500 rpm (0.2 to 8.3 s). -1 , also 60rpm=1s -1It is desirable that (the same applies below). The supply amount of the polishing composition is sufficient to cover the entire object to be polished (flow rate), and can be adjusted according to conditions such as the size of the object to be polished. The method of supplying the polishing composition to the polishing pad is not particularly limited, and, for example, a method of continuous supply using a pump is adopted. In addition, the processing time is not particularly limited as long as the time required to obtain the desired processing result is obtained, but it is desirable to make it shorter due to the high polishing speed.

[0152] Method for manufacturing a substrate

[0153] Another aspect of the present invention relates to a method for manufacturing a substrate comprising a process of polishing an object to be polished using the polishing method.

[0154] The present embodiment may also be described as a preferred example of a method for manufacturing a substrate, comprising the polishing composition or a polishing method using the polishing composition manufactured by the above manufacturing method. In this regard, details regarding the polishing composition, each component included therein, and the polishing target to which it is applied are also the same as those described for the polishing composition. Furthermore, details regarding the raw materials, physical properties, and characteristics of the polishing composition being manufactured, and details regarding the polishing target to which the polishing composition is manufactured, are also the same as those described for the polishing composition or the method for manufacturing the polishing composition. Additionally, details regarding the polishing method are also the same as those described for the polishing method. Accordingly, examples of preferred embodiments may include a method for manufacturing a substrate (polished substrate) in which the polishing target is a substrate, or a method for manufacturing a semiconductor substrate (polished semiconductor substrate) in which the polishing target is a semiconductor substrate. Accordingly, the method for manufacturing a substrate according to one embodiment of the present invention can be preferably used for manufacturing pattern wafers such as polysilicon pattern wafers.

[0155] Although embodiments of the present invention have been described in detail, it is clear that this is illustrative and exemplary and is not limiting, and that the scope of the present invention should be interpreted by the appended claims.

[0156] The present invention includes, but is not limited to, the following embodiments and forms:

[0157] 1. Silica with organic acid fixed to its surface, and,

[0158] polyalkylene glycol

[0159] Contains,

[0160] The molecular weight distribution of the polyethylene glycol equivalent by gel permeation chromatography (GPC) for the above polyalkylene glycol has two or more peaks, and at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 1,000 or more and 6,000 or less,

[0161] At least one peak of the above molecular weight distribution is a peak with a peak top molecular weight of 100 or more and 800 or less, and

[0162] The above polyalkylene glycol contains polyethylene glycol,

[0163] At least one of the peaks having a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol, and

[0164] A polishing composition having a pH of 3 or higher and 6 or lower;

[0165] 2. At least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polyethylene glycol, or

[0166] or,

[0167] The above polyalkylene glycol further comprises polypropylene glycol or polybutylene glycol, and at least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polypropylene glycol or polybutylene glycol,

[0168] The polishing composition described in 1. above.

[0169] 3. The polishing composition described in 1. or 2., wherein the organic acid is a sulfonic acid or a carboxylic acid.

[0170] 4. A polishing composition described in any one of 1 to 3, wherein the average primary particle size of the silica with the organic acid fixed to its surface is 10 nm or more and 50 nm or less.

[0171] 5. A polishing composition described in any one of 1 to 4, wherein the average secondary particle size of the silica with the organic acid fixed on its surface is 20 nm or more and 100 nm or less.

[0172] 6. A polishing composition described in any one of 1 to 5, wherein, in the silica having the organic acid fixed to its surface, the silica prior to fixation of the organic acid is colloidal silica produced by the sol-gel method or the sodium silicate method.

[0173] 7. A polishing composition described in any one of 1 to 6, further containing a polishing accelerator.

[0174] 8. A polishing composition described in any one of 1 to 7, further containing a step improvement agent.

[0175] 9. A polishing composition described in any one of 1 to 8, further containing acid.

[0176] 10. A polishing composition described in any one of 1 to 9, used for polishing an object to be polished, comprising at least one of a material having silicon-nitrogen bonds, a material having silicon-oxygen bonds, and a material having silicon-silicon bonds.

[0177] 11. Silica with organic acid fixed to its surface, and,

[0178] Polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less in the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC), and

[0179] Polyalkylene glycol having a peak top molecular weight of 100 or more and 800 or less in the molecular weight distribution in terms of polyethylene glycol by gel permeation chromatography (GPC).

[0180] having a mixing process for mixing,

[0181] A method for preparing a polishing composition having a pH of 3 or higher and 6 or lower.

[0182] 12. Using the polishing composition described in any one of 1. to 10. above,

[0183] or,

[0184] A polishing method for preparing a polishing composition by the manufacturing method of 11 above, and polishing an object to be polished using the said polishing composition.

[0185] 13. The polishing method described in 12, wherein the polishing target comprises at least one of a material having silicon-nitrogen bonds, a material having silicon-oxygen bonds, and a material having silicon-silicon bonds.

[0186] 14. A method for manufacturing a polished substrate, wherein the object to be polished is a substrate, and the method for polishing the object to be polished is a polishing method described in 12 or 13.

[0187] [Example]

[0188] The present invention will be explained in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. In addition, in the following examples, unless specifically stated otherwise, operations were performed under conditions of room temperature (25°C) and relative humidity of 40 to 50%RH.

[0189] <Preparation of abrasive composition>

[0190] Each polishing composition was obtained by adding abrasive particles, polyalkylene glycol or ethylene glycol (EG), a pH adjuster, and other additives as needed to water as a solvent, and stirring and mixing (mixing temperature: about 25°C, mixing time: about 10 minutes). Here, the types and concentrations (content, amount added) of each component used in the preparation of each polishing composition are shown in Table 1 and Table 2 below. In addition, the concentration (content, amount added) of the pH adjuster was set to an amount such that the resulting polishing composition has the pH listed in Table 1 and Table 2 below.

[0191] In addition, the pH of the polishing composition (liquid temperature: 25℃) was checked using a pH meter (manufactured by Horiba Seisakusho Co., Ltd. Model No.: LAQUA).

[0192] In addition, the zeta potential [mV] of the abrasive particles in the polishing composition was calculated by supplying the polishing composition to the ELS-Z2 manufactured by Otsuka Denshi Co., Ltd., measuring it using a flow cell at a measurement temperature of 25°C using the laser Doppler method (electrophoretic light scattering measurement method), and interpreting the obtained data using Smoluchowski's equation.

[0193] Details of the abrasive particles and polyalkylene glycol used in the preparation of each abrasive composition are shown below.

[0194] (Georip)

[0195] · Grain 1: Silica with sulfonic acid immobilized on the surface (average primary particle size 14 nm, average secondary particle size 34 nm, cocoon-shaped; unmodified (before modification, before organic acid immobilization) silica is colloidal silica prepared by the sol-gel method);

[0196] · Grain 2: Silica with sulfonic acid immobilized on the surface (average primary particle size 32 nm, average secondary particle size 69 nm, cocoon-shaped; unmodified (before modification, before organic acid immobilization) silica is colloidal silica prepared by the sol-gel method);

[0197] · Grain 3: Silica with sulfonic acid immobilized on the surface (average primary particle size 12 nm, average secondary particle size 53 nm, cocoon-shaped; unmodified (before modification, before organic acid immobilization) silica is colloidal silica prepared by the sodium silicate method);

[0198] · Grain A: Unmodified silica (average primary particle size 14 nm, average secondary particle size 34 nm, cocoon-shaped, colloidal silica prepared by the sol-gel method);

[0199] (Polyalkylene glycol)

[0200] · Polyethylene Glycol 200 (PEG200) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 200, polyethylene glycol having a peak with a molecular weight of 200 as the top peak);

[0201] · Polyethylene Glycol 600 (PEG600) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 600, polyethylene glycol having a peak with a molecular weight of 600 as the top peak);

[0202] · Polyethylene Glycol 1000 (PEG1000) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 1,000, polyethylene glycol having a peak with a molecular weight of 1,000 as the top peak);

[0203] · Polyethylene Glycol 1540 (PEG1540) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 1,540, polyethylene glycol having a peak with a molecular weight of 1,540 as the top peak);

[0204] · Polyethylene Glycol 2000 (PEG2000) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 2,000, polyethylene glycol having a peak with a molecular weight of 2,000 as the top peak);

[0205] · Polyethylene Glycol 4000 (PEG4000) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 4,000, polyethylene glycol having a peak with a molecular weight of 4,000 as the top peak);

[0206] · Polyethylene Glycol 6000 (PEG6000) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 6,000, polyethylene glycol having a peak with a molecular weight of 6,000 as the top peak);

[0207] · Polyethylene Glycol 8000 (PEG8000) (manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 8,000, polyethylene glycol having a peak with a molecular weight of 8,000);

[0208] · Polyethylene glycol 10000 (PEG10000) (Manufactured by Alfa Aesar, product name Polyethylene glycol 10,000, polyethylene glycol having a peak with a molecular weight of 10,000);

[0209] · Polyethylene glycol 15000 (PEG15000) (polyethylene glycol having a peak with a molecular weight of 15,000 as the top peak);

[0210] · Polyethylene Glycol 20000 (PEG20000) (Manufactured by Fujifilm Wako Junyaku Co., Ltd., product name Polyethylene Glycol 20,000, polyethylene glycol having a peak with a molecular weight of 20,000 as the peak top);

[0211] · Polypropylene Glycol 400 (PPG400) (Manufactured by Fujifilm Wako Junyaku Co., Ltd., Product name: Polypropylene Glycol, Diol type, 400, Top peak: Polypropylene glycol having a peak of molecular weight 400)

[0212] In addition, in Tables 1 and 2 below, for example, in the column of the type “peak top molecular weight less than 1000 or EG” of polishing composition 1, “PEG200 / PEG600” indicates that PEG200 and PEG600 are used together. Also, in the column of the concentration (g / L), “0.2 / 0.4” indicates that the concentration of PEG200 is 0.2 g / L and the concentration of PEG600 is 0.4 g / L. In addition, other combinations of types and combinations of concentrations are indicated in the same manner.

[0213] <Evaluation of Molecular Weight Distribution and Peak Top Molecular Weight in the Molecular Weight Distribution>

[0214] The molecular weight distribution of each polyalkylene glycol used as the above raw material and the peak top molecular weight in the said molecular weight distribution were measured by gel permeation chromatography (GPC).

[0215] In addition, the molecular weight distribution of polyethylene glycol equivalent as the total polyalkylene glycol included in the polishing composition, and the peak top molecular weight of the peak in the said molecular weight distribution were measured by gel permeation chromatography (GPC).

[0216] The measurement conditions for the molecular weight distribution and peak top molecular weight of polyalkylene glycol are as follows. In addition, polyethylene glycol was used as a standard substance.

[0217] GPC device: Manufactured by Shimazu Seisakusho Co., Ltd.

[0218] Format: Prominence+ELSD Detector (ELSD-LTII)

[0219] Column: VP-ODS (Manufactured by Shimazu Seisakusho, Kabushiki Kaisha)

[0220] Mobile phase A: MeOH

[0221] B: 1% aqueous solution of acetic acid

[0222] Flow rate: 1 mL / min

[0223] Detector: ELSD temp. 40℃, Gain 8, N2GAS 350kPa

[0224] Oven temperature: 40℃

[0225] Injection volume: 40μl

[0226] As a result of this measurement, the value of the peak top molecular weight of each peak in the molecular weight distribution of the total polyalkylene glycol included in the polishing composition was substantially the same as the value of the peak top molecular weight of the peak in the molecular weight distribution relating to the respective raw material polyalkylene glycol.

[0227] <Polishing Method>

[0228] Using each polishing composition prepared above, the surface of each object to be polished was polished under the following apparatus and conditions. Here, the polishing conditions and the objects to be polished are as follows.

[0229] (Grinding conditions)

[0230] Polisher: CMP single-sided polisher for 200mm wafers

[0231] Pad: Polyurethane pad

[0232] Pressure: 3 psi (approx. 20.7 kPa)

[0233] Plate rotation speed: 90 rpm (1.5 s -1 )

[0234] Flow rate of abrasive composition: 130 ml / min

[0235] Polishing time: 1 minute

[0236] Polishing Target: 200mm Wafer (Poly-Si, SiN, TEOS-SiO)

[0237] Polycrystalline Silicon (Poly-Si): Manufactured by Low Pressure Chemical Vapor Deposition (LPCVD): Thickness 5,000 Å

[0238] Silicon Nitride (SiN): Prepared by Low Pressure Chemical Vapor Deposition (LPCVD): Thickness 3,500 Å

[0239] Silicon oxide derived from tetraethyl orthosilicate (TEOS) (TEOS-SiO): Prepared by physical vapor deposition (PVD): Thickness 10,000 Å

[0240] The polishing speed was evaluated by determining the film thickness before and after polishing using an optical interference film thickness measuring device and dividing the difference by the polishing time.

[0241] Regarding the step, an 8-inch Poly-Si pattern wafer having the following configuration was polished, and for a section with a line and space of 0.25 μm / 0.25 μm (hereinafter also referred to as the wiring section), the step difference between the wiring section and the surrounding section was measured using an AFM (atomic force microscope).

[0242] ≪8-inch Poly-Si Patterned Wafer≫

[0243] specification

[0244] Layer 1: P-TEOS-SiO (Plasma TEOS-SiO) thickness 1,000 Å

[0245] Layer 2: Poly-Si thickness 500Å

[0246] 3rd layer: 854 pattern + etching

[0247] 4th layer: SiN thickness 1,000 Å

[0248] Here, erosion refers to a phenomenon in which the Poly-Si portion of the wiring section becomes concave compared to the surrounding portion of the wiring section. Erosion was evaluated by comparing the Poly-Si portion of the wiring section after polishing with the height difference around the wiring section.

[0249] In addition, dishing refers to the phenomenon where the SiN portion of the wiring becomes concave compared to the surrounding area. For dishing, the difference in height between the SiN portion of the wiring and the surrounding area after polishing was evaluated.

[0250] In addition, in this evaluation, it was determined that a higher polishing rate of SiN is desirable.

[0251] In addition, in this evaluation, the ratio of the polishing rate of SiN (Å / min) to the polishing rate of TEOS-SiO (selectivity of SiN to TEOS-SiO: SiN / TEOS-SiO) and the ratio of the polishing rate of SiN (Å / min) to the polishing rate of Poly-Si (selectivity of SiN to Poly-Si: SiN / Poly-Si) are each preferred to be higher, and it was determined that the selectivity is excellent if both are 25 or higher.

[0252] In addition, in this evaluation, it was determined that smaller erosion and dishing are desirable, and that if erosion is 45 Å or less and dishing is 25 Å or less, the step reduction effect is excellent.

[0253] The formulations and physical properties of each polishing composition are shown in Table 1 and Table 2 below. In addition, the evaluation results of each polishing composition are shown in Table 3 below.

[0254]

[0255]

[0256]

[0257] As shown in Tables 1 to 3 above, the polishing compositions of the comparative examples correspond to at least one of the following: a low polishing rate of silicon nitride (SiN), a low selectivity ratio of SiN to TEOS-SiO, a low selectivity ratio of SiN to Poly-Si, a large erosion, and a large dishing, and it was confirmed that a sufficient effect was not obtained.

[0258] Meanwhile, it was confirmed that the polishing composition according to the present invention has a high polishing rate of silicon nitride (SiN), a significantly high selectivity ratio of SiN to TEOS-SiO and SiN to Poly-Si, and very small erosion and dishing, and a significantly excellent step reduction effect.

[0259] This application is based on Japanese Patent Application No. 2020-163619 filed on September 29, 2020 and Japanese Patent Application No. 2021-118843 filed on July 19, 2021, the entire contents of which are incorporated herein by reference.

Claims

Claim 1 The apparatus comprises silica with an organic acid immobilized on its surface and polyalkylene glycol, wherein the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC) regarding the polyalkylene glycol has two or more peaks, at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 1,000 or more and 6,000 or less, at least one peak of the molecular weight distribution is a peak with a peak top molecular weight of 100 or more and 800 or less, and at least one of the peaks with a peak top molecular weight of 1,000 or more and 6,000 or less is a peak derived from polyethylene glycol, and the polyalkylene glycol comprises polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less in the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC), and polyalkylene glycol having a peak top molecular weight of 100 or more and 800 A polishing composition containing polyalkylene glycol with a peak top molecular weight of 1,000 or more and 6,000 or less, wherein the ratio of the amount of polyalkylene glycol with a peak top molecular weight of 1,000 or more and 6,000 or less to the total amount of added polyalkylene glycol with a peak top molecular weight of 100 or more and 800 or less is 20 mass% or more and 85 mass% or less, and the pH is 3 or more and 6 or less. Claim 2 A polishing composition according to claim 1, wherein at least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polyethylene glycol, or wherein the polyalkylene glycol further comprises polypropylene glycol or polybutylene glycol and at least one of the peaks having a peak top molecular weight of 100 or more and 800 or less is a peak derived from polypropylene glycol or polybutylene glycol. Claim 3 A polishing composition according to claim 1, wherein the organic acid is a sulfonic acid or a carboxylic acid. Claim 4 A polishing composition according to claim 1, wherein the average primary particle size of the silica with the organic acid fixed on its surface is 10 nm or more and 50 nm or less. Claim 5 A polishing composition according to claim 1, wherein the average secondary particle size of the silica with the organic acid fixed on its surface is 20 nm or more and 100 nm or less. Claim 6 A polishing composition according to claim 1, wherein, in the silica having the organic acid fixed on its surface, the silica prior to the fixation of the organic acid is colloidal silica produced by the sol-gel method or the sodium silicate method. Claim 7 A polishing composition according to claim 1, further containing a polishing accelerator. Claim 8 A polishing composition according to claim 1, further containing a step improvement agent. Claim 9 A polishing composition according to claim 1, further containing acid. Claim 10 A polishing composition used for polishing an object to be polished, comprising at least one of a material having a silicon-nitrogen bond, a material having a silicon-oxygen bond, and a material having a silicon-silicon bond, in accordance with claim 1. Claim 11 A method for preparing a polishing composition having a mixing process of mixing silica with an organic acid fixed on its surface, polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less in the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC), and polyalkylene glycol having a peak top molecular weight of 100 or more and 800 or less in the molecular weight distribution of polyethylene glycol equivalent by gel permeation chromatography (GPC), wherein the ratio of the amount of polyethylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less to the total amount of added polyethylene glycol having a peak top molecular weight of 100 or more and 800 or less to the amount of added polyalkylene glycol having a peak top molecular weight of 1,000 or more and 6,000 or less is 20 mass% or more and 85 mass% or less, and the pH is 3 or more and 6 or less. Claim 12 A polishing method for polishing an object to be polished using a polishing composition described in claim 1. Claim 13 A polishing method according to claim 12, wherein the polishing target comprises at least one of a material having silicon-nitrogen bonds, a material having silicon-oxygen bonds, and a material having silicon-silicon bonds. Claim 14 A method for manufacturing a polished substrate, wherein the object to be polished is a substrate, and the method comprises a process of polishing the object to be polished using the polishing method described in claim 12.

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