Constricted-type linked silica particles, a dispersion of constricted-type linked silica particles containing a plurality of such particles, and a method for producing the same

Abstract

To provide a constriction-type silica particle conjugate that exhibits excellent abrasiveness when used as a polishing composition.SOLUTION: A constriction-type silica particle conjugate comprises 5 to 50 primary silica particles connected to one another and meets requirements of (A) to (C) below. (A) An average particle size of the silica primary particles is 5 to 600 nm. (B) A particle size coefficient of variation (CV value) of the silica primary particles is 15 to 90%. (C) A specific connecting portion where the silica primary particles that are three in number, respectively having a particle size of a, b, and c, are connected in this order and a>b and c>b are satisfied is present.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to linked silica particles having a constricted structure, i.e., linked silica particles, a dispersion of linked silica particles in which the linked silica particles are dispersed in a solvent, and a method for producing the same. [Background technology]

[0002] Among silica microparticle dispersions (silica sols) in which silica microparticles are dispersed in a solvent, silica microparticle dispersions in which the silica microparticles have a shape other than spherical include those in which the silica microparticles have an external shape of chain, bead, spheroid, or linked particles (linked silica microparticles). In particular, those in which the silica microparticles are linked particles (linked silica particles) are called linked silica microparticle dispersions, and are used as abrasive dispersions for polishing various substrates, including hard disk substrates.

[0003] Patent Document 1 discloses a particle-linked alumina-silica composite sol, comprising particle-linked alumina-silica composite microparticles dispersed in a dispersion medium, each of which comprises a structure in which two or more alumina-silica composite primary particles are bonded together. The average particle diameter, as measured by image analysis, is in the range of 5 to 300 nm. It also discloses a method for producing the same. Patent Document 1 describes a particle-linked alumina-silica composite microparticle that contains, as alumina-silica composite primary particles, spherical particles having multiple wart-like protrusions on their surfaces. This invention has a unique structure that differs from ordinary particle-linked silica microparticles or non-spherical alumina-silica composite microparticles. For this reason, the sol is useful, for example, as an abrasive and a polishing composition, and is particularly effective in achieving a high polishing rate. However, aluminum is undesirable because it can be a contaminant depending on the type of substrate being polished.

[0004] Patent Document 2 discloses a particle-linked silica sol comprising particle-linked silica microparticles dispersed in a dispersion medium, the particle-linked silica microparticles comprising a structure in which two or more primary silica particles are bonded together, and the average particle diameter measured by image analysis is in the range of 5 to 300 nm. Patent Document 2 describes a particle-linked silica microparticle characterized in that the primary silica particles comprise spherical particles having multiple wart-like protrusions on their surfaces. This invention has a unique structure distinct from ordinary particle-linked silica microparticles or non-spherical silica microparticles, making it useful, for example, as an abrasive and a polishing composition, and is particularly effective in achieving a high polishing rate. However, the inclusion of a tetrapod-type bond and the presence of wart-like protrusions can easily cause localized stress concentration on the polished substrate, potentially resulting in scratches and other polishing defects. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-155180 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-016702 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide constricted linked silica particles that exhibit excellent polishing properties when used in a polishing composition, a dispersion of constricted linked silica particles containing a plurality of such particles, and a method for producing the same. [Means for solving the problem]

[0007] The present inventors have conducted extensive research and have completed the present invention, which comprises the following (1) to (9). (1) A constricted silica particle linked body in which 5 to 50 silica primary particles are linked and which satisfies the following requirements (A) to (C): (A) The average particle size of the silica primary particles is 5 to 600 nm. (B) The particle size coefficient of variation (CV value) of the silica primary particles is 15 to 90%. (C) Three of the silica primary particles having particle diameters a, b, and c are connected in this order to form a specific connecting portion that satisfies a>b and c>b. (2) The constricted silica particle linked structure according to (1) above, which further satisfies the following requirement (D): (D) a-b ≥ (b / 10) and c-b ≥ (b / 10). (3) The constricted silica particle linked structure according to (1) or (2) above, which further satisfies the following requirement (E): (E) Contains two or more of the specific linking portions. (4) A particle group at least partly comprising the constricted silica particle linked bodies according to any one of (1) to (3) above is dispersed in a dispersion medium, The particle group has an average particle size of 50 to 600 nm as measured by dynamic light scattering. (5) The dispersion liquid of linked constricted silica particles according to (4) above, wherein the proportion (number ratio) of the linked constricted silica particles in the particle group is 10 to 100%. (6) A dispersion of linked constricted silica particles, comprising a particle group dispersed in a dispersion medium, at least some of which are linked constricted silica particles having specific linking portions satisfying a>b and c>b, each of which is composed of three primary silica particles having particle diameters a, b, and c, linked in that order, and the specific linking portions satisfying a>b and c>b, and the dispersion satisfies the following requirements [1] to [4]: [1] The average particle size of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a portion of the particle group is 5 to 600 nm. [2] The particle size coefficient of variation (CV value) of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a portion of the particle group is 15 to 90% on average. [3] In the plurality of constricted linked silica particles constituting at least a part of the particle group, the number of primary silica particles constituting one constricted linked silica particle is 5 to 50 on average. [4] The average particle size measured by dynamic light scattering is 50 to 600 nm. (7) The dispersion of linked constricted silica particles according to the above (6), which further satisfies the following requirement [5]: [5] The particle group contains the constricted silica particle linked bodies in an amount (number ratio) of 10 to 100%. (8) a preparation step of preparing dispersions in which two types of silica primary particles having an average particle size difference of 10% or more are dispersed, and mixing these to obtain a preparation dispersion; adding a cationic organic polymer component to the preparatory dispersion; a method for producing a dispersion of linked constricted silica particles, which provides the dispersion of linked constricted silica particles described in any one of (4) to (7) above. (9) In the adding step, The method for producing a dispersion of linked constricted silica particles according to (8) above, wherein the cationic organic polymer component is added to the preparatory dispersion, and then a silicic acid solution is further added to grow necks. [Effects of the Invention]

[0008] According to the present invention, there are provided constricted linked silica particles that exhibit excellent polishing properties when used as a polishing composition, a dispersion of constricted linked silica particles containing a plurality of such particles, and a method for producing the same. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a simulated photograph or image obtained by observing the linked body of the present invention under a transmission electron microscope at 200,000 magnifications. [Figure 2] FIG. 1 is another diagram showing a simulated photograph or image obtained by observing the linked body of the present invention under a transmission electron microscope at 200,000 magnifications. [Figure 3] Figure 3(a) is an image of the conjugate of the present invention obtained by observing it under a transmission electron microscope at 200,000 magnifications, and Figure 3(b) is a photograph of the outline of the conjugate of the present invention shown in Figure 3(a). [Figure 4]FIG. 10 is another diagram showing a simulated photograph or image obtained by observing the linked body of the present invention under a transmission electron microscope at 200,000 magnifications. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will now be described. The present invention provides a constricted silica particle linked body in which 5 to 50 silica primary particles are linked together and which satisfies the following requirements (A) to (C): (A) The average particle size of the silica primary particles is 5 to 600 nm. (B) The particle size coefficient of variation (CV value) of the silica primary particles is 15 to 90%. (C) Three of the silica primary particles having particle diameters a, b, and c are connected in this order to form a specific connecting portion that satisfies a>b and c>b. Such a single constricted silica particle linked body will hereinafter also be referred to as the "linked body of the present invention."

[0011] The present invention also provides a dispersion liquid of constricted silica particle links, in which a particle group at least partly comprising the linked particles of the present invention is dispersed in a dispersion medium, and the average particle diameter measured by dynamic light scattering is 50 to 600 nm. Such a dispersion of linked constricted silica particles will hereinafter also be referred to as the "first dispersion of the present invention."

[0012] The present invention also provides a dispersion liquid of linked constricted silica particles, which is obtained by dispersing in a dispersion medium a particle group at least partly made up of linked constricted silica particles having specific linking parts where three primary silica particles having particle diameters a, b, and c are linked in that order and satisfy the relationships a>b and c>b, and which satisfies the following requirements [1] to [4]: [1] The average particle size of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a portion of the particle group is 5 to 600 nm. [2] The particle size coefficient of variation (CV value) of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a portion of the particle group is 15 to 90% on average. [3] In the plurality of constricted linked silica particles constituting at least a part of the particle group, the number of primary silica particles constituting one constricted linked silica particle is 5 to 50 on average. [4] The average particle size measured by dynamic light scattering is 50 to 600 nm. Such a dispersion of linked constricted silica particles is hereinafter also referred to as the "second dispersion of the present invention."

[0013] The first dispersion of the present invention and the second dispersion of the present invention may be the same.

[0014] In the following description, when simply referring to "the dispersion of the present invention," this refers to both or either of "the first dispersion of the present invention" and "the second dispersion of the present invention."

[0015] The present invention also provides a method for producing a dispersion of linked constricted silica particles, the method comprising: a preparatory step of preparing dispersions in which two types of silica primary particles having an average particle size difference of 10% or more are dispersed, and mixing the dispersions to obtain a preparatory dispersion; and an adding step of adding a cationic organic polymer component to the preparatory dispersion, thereby obtaining the dispersion of the present invention. Such a method for producing a dispersion of linked constricted silica particles is hereinafter also referred to as the "production method of the present invention."

[0016] <The linker of the present invention> The connector of the present invention will now be described. A single particle of the linked particle of the present invention is formed by linking together primary silica particles. The connection between the silica primary particles and other silica primary particles involves a physical and / or chemical bond, for example, a chemical bond such as a siloxane bond formed by a condensation reaction between silanol groups on the surface of each silica primary particle.

[0017] The shape of the silica primary particles is not particularly limited, and is preferably spherical or approximately spherical, but may also be oval, rod-shaped, or the like.

[0018] <Number of connected silica primary particles> The linked particles of the present invention have 5 to 50 linked primary silica particles per particle.

[0019] When the number of linked silica primary particles in one particle of the linked particle of the present invention (hereinafter also referred to as "linkage number") is 5 to 50, when a dispersion containing a large number of the linked particles of the present invention is used as a polishing abrasive, the polishing rate is excellent and the occurrence of defects is suppressed, resulting in excellent polishing performance. When the linkage number is less than 5, when a dispersion containing a large number of the linked particles of the present invention is used as a polishing abrasive, the dynamic contact area with the object to be polished may not be sufficient, and the desired polishing rate may not be achieved. On the other hand, when the linkage number exceeds 50, when a dispersion containing the linked particles of the present invention is used as a polishing abrasive, defects, etc. may occur.

[0020] The number of linked units is preferably 5 to 15.

[0021] The number of linked molecules in one linked molecule of the present invention can be measured by observing the linked molecule of the present invention under a transmission electron microscope or a scanning electron microscope at 200,000 magnifications.

[0022] <Average particle size of primary silica particles> The average particle size of the primary silica particles constituting one particle of the linked body of the present invention is 5 to 600 nm, preferably 5 to 400 nm, and more preferably 10 to 300 nm. When the average particle size is in the range of 5 to 600 nm, an excellent polishing rate is exhibited when a dispersion containing a large number of the linked particles of the present invention is used as a polishing abrasive. This is presumably because, when the linked particles of the present invention are in this particle size range, each linked particle is in the form of a single particle, the number ratio of the linked particles in the dispersion is in an appropriate range, and a sufficient contact area with the workpiece can be maintained. If the average particle size is less than 5 nm, the linked bodies of the present invention tend to form clumps, and as a result, in polishing applications, a sufficient polishing rate may not be achieved, possibly because stress concentration on the polishing substrate is not achieved. On the other hand, if the average particle size exceeds 600 nm, for example, in polishing applications, the contact area between the object to be polished (e.g., a substrate) and the linked body of the present invention may decrease, resulting in a decrease in the polishing rate, and scratches (linear marks) may occur on the polished surface of the object to be polished.

[0023] The method for determining the average particle size of the primary silica particles constituting one linked particle of the present invention will be described with reference to FIG. First, a single linked complex of the present invention is observed under a transmission electron microscope at 200,000 magnifications to obtain a photograph or image. Figure 1 is a diagram showing a simulated view of the linked complex of the present invention shown in the photograph or image obtained in this manner. The linked complex of the present invention may have a three-dimensional structure, but in the photograph or image observed under a transmission electron microscope as shown in Figure 1, it is treated as two-dimensional. Eight primary silica particles are linked together in the linked body of the present invention shown in Fig. 1. Here, the eight primary silica particles are designated as P1, P2, P3, P4, P5, P6, P7, and P8, and P1 to P6 are linked together in this order, with P5 to P7 and P8 branching out and linked together. The linker of the present invention is not limited to the embodiment shown in FIG. 1, and may be, for example, unbranched. In a photograph or image obtained by observing the linked body of the present invention at 200,000 magnification using a transmission electron microscope, two tangent lines are drawn that touch both two adjacent silica primary particles, as shown in Figure 1. First, two tangent lines are drawn that touch both P1 and P2, and these are designated C12a and C12b, respectively. Then, at P1, the two tangent lines (C12a, C12b) are joined at two points of contact, and the length of this line segment is measured to determine the particle diameter L1. Similarly, at P2, the two tangent lines (C12a, C12b) are joined at two points of contact, and the length of this line segment is measured to determine the particle diameter L2a. Next, two tangent lines (C23a, C23b) are drawn that touch both P2 and P3. Then, at P2, the two tangent lines (C23a, C23b) are joined at two points of contact, and the length of this line segment is measured and defined as the particle diameter L2b. Similarly, at P3, the two tangent lines (C23a, C23b) are joined at two points of contact, and the length of this line segment is measured and defined as the particle diameter L3a. Similarly, for other primary silica particles, two tangent lines are drawn that touch both of two adjacent primary silica particles, and two contact points that touch the two tangent lines are connected, and the length of the line segment is measured to determine the particle diameter of the primary silica particle. When three silica primary particles (P4, P6, P7) are in contact, as in the case of P5 shown in Figure 1, three particle sizes (L5a, L5b, L5c) are measured. Although not included in the case of Figure 1, the same applies when four or more silica primary particles are in contact, and the same number of particle sizes as the number of contacting silica primary particles are measured. In this way, by drawing two tangent lines that touch both of two adjacent silica primary particles and measuring the lengths of the two line segments at which they contact, one line segment length (particle diameter L1, particle diameter L6, and particle diameter L7) is measured for each of the silica primary particles at the extreme ends of the linked silica primary particles constituting the linked aggregate of the present invention, i.e., P1, P6, and P8 in the case of Figure 1. Furthermore, for particles other than those at the extreme ends, i.e., P2 to P5 and P7 in the case of Figure 1, two or more line segment lengths are measured for each. For example, for P2, particle diameter L2a and particle diameter L2b are measured, and for P5, particle diameter L5a, particle diameter L5b, and particle diameter L5c are measured. For the silica primary particles constituting the linked body of the present invention that are located at the extreme ends, such as P1, P6, and P8 shown here, the particle diameter of each silica primary particle (P1, P6, and P8) is the particle diameter of one line segment, i.e., particle diameter L1, particle diameter L6, and particle diameter L8. For the silica primary particles constituting the linked body of the present invention that are not located at the extreme ends, such as P2 to P5 and P7 shown here, the average value of two or more line segments is taken as the particle diameter of the silica primary particle. For example, in the case of P2, the particle diameter of P2 is taken as the simple average of particle diameter L2a and particle diameter L2b. Similarly, in the case of P5, the particle diameter of P5 is taken as the simple average of particle diameter L5a, particle diameter L5b, and particle diameter L5c. The same applies when four or more silica primary particles are in contact with each other; the particle diameters of the same number of silica primary particles in contact are measured, and the simple average of these particle diameters is taken as the particle diameter of the silica primary particle. After determining the particle sizes of all the primary silica particles constituting the linked body of the present invention in this manner, the values ​​are simply averaged to determine the average particle size of one primary silica particle constituting the linked body of the present invention. It should be noted that a scanning electron microscope photograph may be used instead of a transmission electron microscope photograph.

[0024] <Particle size variation coefficient (CV value) of primary silica particles> The particle size coefficient of variation (CV value) of the primary silica particles constituting one linked particle of the present invention is 15 to 90%, preferably 15 to 60%, and more preferably 15 to 50%. When the particle size coefficient of variation (CV value) is within the above range, there is an appropriate difference in particle size between the primary silica particles constituting the linked particles of the present invention, which is preferable in that it increases the dynamic contact area while suppressing a decrease in stress concentration. If the coefficient of variation is smaller than the above range, the static contact area between the primary particles constituting the linked particles and the object to be polished increases, which may result in a decrease in stress concentration and make it impossible to obtain the desired polishing rate. On the other hand, if the coefficient of variation is larger than the above range, the static contact area between the primary particles constituting the linked particles and the polishing substrate decreases, which may result in an increase in stress concentration and may cause scratches (linear marks) on the polishing surface of the object to be polished, which is undesirable.

[0025] A method for measuring the particle size coefficient of variation (CV value) of the primary silica particles constituting one linked particle of the present invention will be described. First, the particle diameter of each of the primary silica particles constituting the linked bodies of the present invention is determined by the method for determining the average particle diameter of the primary silica particles described above with reference to Fig. 1. In the case of the example shown in Fig. 1, the particle diameter of each of the primary silica particles P1 to P8 is determined. Then, after calculating the standard deviation from these values, the standard deviation is divided by the value of the average particle diameter calculated by the method for calculating the average particle diameter of silica primary particles explained above with reference to FIG. 1, and the obtained quotient is used as the particle diameter coefficient of variation (CV value).

[0026] <Specific connection part> The linked material of the present invention is formed by linking primary silica particles as described above, and has a specific linking portion as a part thereof. The specific connection portion refers to a portion where three primary silica particles having particle sizes a, b, and c are connected in this order, satisfying a>b and c>b.

[0027] The specific connecting portion will be explained with reference to FIGS. Fig. 2 is a diagram showing a simulated photograph or image obtained by observing the linked body of the present invention with a transmission electron microscope at 200,000 magnifications. When the particle diameters of the primary silica particles constituting the linked body of the present invention are determined by the method for determining the average particle diameter of the primary silica particles described above with reference to Fig. 1, it is assumed that the particle diameters of the three primary silica particles (p1, p2, p3) are a, b, and c, respectively. As shown in FIG. 2, when a>b and c>b are satisfied, among the silica primary particles constituting the linked body of the present invention, these three silica primary particles (p1, p2, p3) are considered to constitute a specific linked portion.

[0028] Next, Figure 3(a) is an image obtained by observing the linker of the present invention at 200,000 magnifications using a transmission electron microscope, and Figure 3(b) is a photograph showing the outline of the linker of the present invention shown in Figure 3(a). The connected silica primary particles shown in FIG. 3 are designated as p1 to p8 as shown in FIG. Then, the particle diameter of each of these primary silica particles p1 to p8 was determined using the method for determining the average particle diameter of the primary silica particles described above with reference to FIG. 1, and the results were p1: 48.0 nm, p2: 45.0 nm, p3: 45.0 nm, p4: 45.0 nm, p5: 26.0 nm, p6: 47.0 nm, p7: 41.0 nm, and p8: 44.0 nm. In this case, if the particle diameters of p4, p5, and p6 are a, b, and c, respectively, then a>b and c>b are satisfied. Therefore, p4, p5, and p6 constitute a specific linking portion. Furthermore, when the particle diameters of p6, p7, and p8 are a, b, and c, respectively, a>b and c>b are satisfied. Therefore, p6, p7, and p8 constitute a specific linking portion.

[0029] Since the linked particles of the present invention have the specific linking moieties described above, when a dispersion containing particles containing the linked particles dispersed in a dispersion medium is used to polish an object to be polished, the large silica primary particles tend to come into contact with the substrate during polishing and are susceptible to stress concentration, thereby contributing to an increase in the polishing rate. Furthermore, since the silica primary particle diameters at the specific linking moieties satisfy the relationships a > b and c > b, the strength of the linked particles themselves can be increased, thereby suppressing particle collapse during polishing and achieving the desired polishing performance.

[0030] Furthermore, the specific linking portion consisting of p4, p5, and p6 and the specific linking portion consisting of p6, p7, and p8 both satisfy a-b ≥ (b / 10) and c-b ≥ (b / 10). Although it is not essential for the linked particles of the present invention to satisfy a-b ≥ (b / 10) and c-b ≥ (b / 10), it is preferable for the linked particles to satisfy a-b ≥ (b / 10) and c-b ≥ (b / 10), which is advantageous in that it prevents the linked particles from collapsing and provides the desired polishing performance.

[0031] The linked body of the present invention preferably contains two or more of the above-mentioned specific linking moieties, as exemplified in Figure 3. In this case, it is preferable in that a high polishing rate can be obtained while suppressing particle collapse.

[0032] <Neck and its depth> The bond between one of the primary silica particles constituting one linked particle of the present invention and another primary silica particle directly bonded thereto is called a neck portion, and the depth of the neck portion varies depending on the degree of reinforcement by silicic acid liquid, etc.

[0033] Here, the neck portion and the depth of the neck portion will be explained with reference to FIG. Figure 4 is a simulated photograph or image of a single linked particle of the present invention observed at 200,000 magnifications under a transmission electron microscope. The linked particle of the present invention shown in Figure 4 is composed of five linked primary silica particles. Also, as shown in FIG. 4, the five silica primary particles are designated as P1, P2, P3, P4, and P5, and are connected in this order. First, in a photograph or image obtained by observing the linked complex of the present invention at 200,000 magnification using a transmission electron microscope, two tangent lines are drawn that touch both two adjacent silica primary particles, as shown in Figure 4. First, two tangent lines are drawn that touch both P1 and P2, and these lines are designated C12a and C12b. Then, when perpendicular lines are drawn from each of the two tangent lines (C12a and C12b) to the contours representing the outer edges of P1 and P2, the contours where the perpendicular lines intersect with the longest perpendicular lines represent the boundary between P1 and P2, and this boundary is considered to be the end of the neck portion. The length of the longest perpendicular line (the length designated by Lm12a and Lm12b in Figure 4) is considered to be the depth of the neck portion between P1 and P2. The same applies to other primary silica particles; when two tangent lines are drawn that touch both of two adjacent primary silica particles, and perpendicular lines are drawn from each of the two tangent lines to the contours that represent the outer edges of the two primary silica particles, if the perpendicular lines are the longest, the contours where the perpendicular lines intersect represent the boundary between the two primary silica particles, and this boundary is the end of the neck portion of the two primary silica particles, and the length of the longest perpendicular line is the depth (Lm) of the neck portion of the two primary silica particles.

[0034] When the average particle size of the silica primary particles determined by the method described above with reference to FIG. 1 is F, Lm is preferably F / 3 or less, more preferably less than F / 6, and even more preferably less than F / 9. In this case, the bond strength between the two silica primary particles bonded to each other tends to be high, so when a polishing object is polished using a dispersion in which a particle group containing such a linked body of the present invention is dispersed in a dispersion medium, the overall linked structure is maintained even under polishing load, a large contact area is obtained between the linked body of the present invention and the polishing substrate, and the desired polishing performance is easily obtained.

[0035] <Coefficient of variation of neck depth> The depth of all necks in the linked body of the present invention is measured by the above-mentioned method. For example, in the case where five silica primary particles are linked together as shown in Figure 4, there are four necks, and therefore the neck depth (Lm) is measured at eight locations. The coefficient of variation of these neck depths (Lm) (coefficient of variation of eight neck depths in the embodiment shown in Figure 4) is preferably 0 to 40%, more preferably 0 to 35%, and even more preferably 0 to 30%. When a polishing object is polished using a dispersion in which particles containing the linked body of the present invention are dispersed in a dispersion medium, particle collapse during polishing is unlikely to occur, the polishing rate is stable, and the contact area between the linked body of the present invention and the polishing object is constant, increasing the polishing rate and reducing the occurrence of defects such as scratches.

[0036] The coefficient of variation of the neck depth means the value obtained by calculating the standard deviation and simple average value from the values ​​of all neck depths (Lm) in one linked body of the present invention (eight neck depths in the case of the embodiment shown in Figure 4), and dividing the standard deviation by the simple average value.

[0037] <Cationic organic polymer component> The linker of the present invention preferably contains a cationic organic polymer component inside. Usually, when cationic organic polymer components coexist with silica microparticles, they are adsorbed onto the surface of the silica microparticles. When silica microparticles with such cationic organic polymer components adsorbed onto their surfaces are used as polishing abrasives, the polishing rate may decrease, possibly because the cationic organic polymer components act as a cushion layer between the object to be polished (substrate, etc.) and the silica microparticles. In addition, the cationic organic polymer components desorbed from the surface of the silica microparticles are undesirably adsorbed onto the object to be polished and contaminate it. In contrast, the linker of the present invention has the advantage that it does not cause the above-mentioned decrease in polishing rate or contamination of the substrate because it encapsulates most of the cationic organic polymer component. When the linker of the present invention encapsulates a cationic organic polymer component inside, the presence of the cationic functional group has an effect, and the surface charge of the linker of the present invention can be preferably controlled.

[0038] In a dispersion liquid in which the particle group containing the linked body of the present invention is dispersed in a dispersion medium, at least a part of the cationic organic polymer component may migrate into the dispersion medium.

[0039] Whether or not the linker of the present invention encapsulates a cationic organic polymer component inside can be confirmed by measuring the chemical oxygen demand (COD) using potassium permanganate. Conversely, when the chemical oxygen demand (COD) of the conjugate of the present invention is measured using potassium permanganate as described below, if the COD is equal to or greater than a specific value, the conjugate of the present invention is deemed to contain a cationic organic polymer component therein. First, 100 g of the conjugate of the present invention is placed in a 300 mL Erlenmeyer flask, water is added to make 100 mL, 10 mL of sulfuric acid (1 + 2) (volume ratio of sulfuric acid 1: water 2) is added, 5 mL of silver nitrate solution (200 g / L) is added, and the mixture is shaken. Then, 10 mL of 5 mmol / L potassium permanganate solution is added, and the flask is placed in a boiling water bath and heated for 30 minutes. At this time, the surface of the boiling water bath should always be above the surface of the sample. Next, add 10 mL of sodium oxalate solution (12.5 mmol / L) and back-titrate with 5 mmol / L potassium permanganate solution while maintaining the temperature at 50-60°C. The endpoint is when the solution turns a pale red color. Separately, a blank test using water is carried out under the same conditions. Then, calculate the amount of oxygen consumed by potassium permanganate in mgO / L using the following formula: COD = (ab) × f × 1000 / V × 0.2 COD: Oxygen consumption by potassium permanganate (mgO / L) a: Amount (mL) of 5mmol / L potassium permanganate solution required for titration b: Amount (mL) of 5 mmol potassium permanganate solution required for titration in the blank test f: Factor of 5mmol / L potassium permanganate solution V: Sample volume (mL) Oxygen equivalent (mg) of 1 mL of 0.2:5 mmol / L potassium permanganate solution When the COD value thus determined is 1000 mg / L or more, the conjugate of the present invention is deemed to contain a cationic organic polymer component therein.

[0040] The cationic organic polymer component that can be encapsulated in the linker of the present invention is not particularly limited, and the molecular structure thereof is also not limited, and may be linear, planar-branched, or three-dimensionally branched.

[0041] The cationic organic polymer component contains a cationic functional group, and may further contain at least one selected from the group consisting of an anionic functional group and a nonionic functional group.

[0042] The weight average molecular weight of the cationic organic polymer component is preferably 300 or more and 10000 or less, more preferably 300 or more and 5000 or less, and particularly preferably 300 or more and 2000 or less. When the weight average molecular weight of the cationic organic polymer component is below the above range, a large amount of the cationic organic polymer component is required to promote the aggregation of the conjugate of the present invention, which is not economically preferable. Further, when the weight average molecular weight of the cationic organic polymer component exceeds the above range, it is difficult to control the aggregation of the conjugate of the present invention, and it tends to be difficult to obtain desired particles.

[0043] Here, the weight average molecular weight of the cationic organic polymer component is measured by a conventionally known method. Examples of the conventionally known method include a light scattering method, an aqueous size exclusion chromatography method (SEC), a gel permeation chromatography method (GPC), and an elevation of boiling point method. Further, when the molecular weight is clear from the information provided by the supplier, that information may be used.

[0044] The cationic organic polymer component is not particularly limited, and examples thereof include poly(diethylaminoethyl methacrylate) (PDEAEM), poly(dimethyldiallylammonium chloride) (PDMDAAC), polyalkyleneimine, and collagen. Here, polyalkyleneimine means, for example, a polymer obtained by polymerizing alkyleneimines having 2 to 8 carbon atoms such as ethyleneimine, propyleneimine, butyleneimine, dimethylethyleneimine, pentyleneimine, hexyleneimine, heptyleneimine, and octyleneimine, and a polymer chemically modified by reacting these with various compounds. Further, collagen means, for example, atelocollagen, gelatin, collagen peptide, and a collagen derivative chemically modified by reacting these with various compounds.

[0045] <Ratio of Ca, Mg, Al and Fe> The linker of the present invention may contain at least one element selected from the group consisting of Ca, Mg, Al, and Fe. However, the total content of Ca, Mg, Al, and Fe in the linker of the present invention is preferably 150 ppm or less, more preferably 50 ppm or less, and even more preferably 25 ppm or less. Furthermore, the Ca content in the linker of the present invention is preferably 10 ppm or less. Furthermore, the Mg content in the linker of the present invention is preferably 10 ppm or less. The Al content in the connected body of the present invention is preferably 60 ppm or less. The Fe content in the linked body of the present invention is preferably 20 ppm or less.

[0046] In the linked body of the present invention, the primary silica particles are directly bonded to each other, for example, by a chemical bond such as a siloxane bond, rather than by a binder component such as CaO, MgO, Al2O3, or Fe2O3. If the linked body of the present invention does not contain CaO, MgO, Al2O3, Fe2O3, etc., when a dispersion in which particle groups containing these particles are dispersed in a dispersion medium is used for polishing semiconductor devices such as semiconductor substrates and wiring boards, there is little risk of metal contamination problems caused by these binder components occurring.

[0047] <First dispersion of the present invention> The first dispersion of the present invention will now be described. The first dispersion of the present invention is one in which a particle group containing a plurality (usually a large number) of the above-described linked bodies of the present invention is dispersed in a dispersion medium. The particle group may all be the linked bodies of the present invention. That is, the particle group in the first dispersion of the present invention may include particles that do not fall under the category of the linker of the present invention. Examples of particles that do not fall under the category of the linked particles of the present invention include silica particles, silica aggregates, and linked particles of silica particles, which do not fall under the category of the linked particles of the present invention. Specific examples include silica fine particles as single particles, and linked silica fine particles in which the number of linked particles is 4 or less.

[0048] The proportion (number ratio) of the constricted silica particle linked bodies in the particle group is preferably 10 to 100%, more preferably 30 to 100%, and even more preferably 50 to 100%. This abundance ratio (number ratio) is calculated by observing the particle group at 200,000 magnification with a scanning electron microscope and determining whether or not 100 randomly selected particles correspond to constricted silica particle linked bodies.

[0049] The dispersion medium is not particularly limited and may be, for example, water, an organic solvent, or a mixture thereof. Examples of the organic solvent include water-soluble organic solvents such as alcohols (methyl alcohol, ethyl alcohol, isopropyl alcohol, etc.), ethers, esters, and ketones.

[0050] The average particle size of the particle group in the first dispersion of the present invention measured by dynamic light scattering is 50 to 600 nm, preferably 60 to 400 nm, and more preferably 70 to 200 nm.

[0051] This average particle diameter is measured using a laser particle analyzer after adding 0.58% aqueous ammonia to a dispersion in which particle groups at least partly comprising the linked bodies of the present invention are dispersed in a dispersion medium, adjusting the silica concentration, converted to SiO2, to 1 mass%. An example of a laser particle analyzer is the Zeta Potential / Particle Size Measurement System ELSZ-1000 manufactured by Otsuka Electronics Co., Ltd. The measurement conditions are as follows: the light source wavelength is 665.70 nm, the temperature is adjusted within a range of 10 to 90° C., and a 10 mm square plastic cell is used.

[0052] The solid content of the first dispersion of the present invention is preferably 2 to 50% by mass, more preferably 5 to 30% by mass. Within this range, particles are less likely to settle over time, and storage stability is excellent. If the solids concentration is too high, particle aggregation and subsequent sedimentation are likely to occur. In this case, when the first dispersion of the present invention is applied to polishing applications, the polishing rate and polishing efficiency may be reduced. Furthermore, during the process of storing or supplying the polishing abrasive dispersion for polishing processing, the polishing abrasive dispersion adhering to the inner wall of the container or supply device easily dries and becomes agglomerates, which may be mixed back into the polishing abrasive dispersion and cause scratches during the polishing processing. If the solid content concentration is too low, the first dispersion of the present invention will need to be concentrated in order to be used for various purposes.

[0053] Here, the solid content concentration in the first dispersion of the present invention can be determined by carrying out ignition loss at 1000°C and weighing.

[0054] <Second dispersion of the present invention> The second dispersion of the present invention will now be described. The second dispersion of the present invention is a constricted silica particle linked dispersion that is obtained by dispersing in a dispersion medium a particle group at least partly made up of constricted silica particle linked structures in which three or more silica primary particles are linked together, three of which form specific linking moieties, and that satisfies specific requirements.

[0055] The second dispersion of the present invention is one in which particle groups are dispersed in a dispersion medium. The particle group contains a plurality (usually a large number) of constricted silica particle linked bodies having a specific linking portion, and the particle group may entirely consist of constricted silica particle linked bodies.

[0056] The particle group in the second dispersion of the present invention may include particles that do not fall under the category of constricted silica particle linked bodies having a specific linking portion. Examples of the constricted silica particle linked bodies that do not include silica particles, silica aggregates, or linked bodies of silica particles as single bodies but that do not have specific linking parts include those.

[0057] In each of the constricted silica particle linked bodies contained in the second dispersion of the present invention, at least three or more silica primary particles are linked together. The connection between the silica primary particles and other silica primary particles involves a physical and / or chemical bond, for example, a chemical bond such as a siloxane bond formed by a condensation reaction between silanol groups on the surface of each silica primary particle.

[0058] The shape of the silica primary particles is not particularly limited, and is preferably spherical or approximately spherical, but may also be oval, rod-shaped, or the like.

[0059] <Specific connection part> The constricted silica particle linked bodies contained in the second dispersion of the present invention are formed by linking primary silica particles as described above, and also have a specific linking moiety as a part thereof. This specific linking portion is the same as the specific linking portion possessed by the aforementioned linked body of the present invention, and refers to a portion in which three primary silica particles having particle diameters a, b, and c are linked in this order, satisfying a>b and c>b. The method for measuring the particle diameters (a, b, c, etc.) of the primary silica particles is the same as that for the linked body of the present invention described above.

[0060] When a polishing target is polished using the second dispersion of the present invention containing the constricted silica particle linked bodies having such specific linking moieties, the large-sized primary silica particles are likely to come into contact with the substrate during polishing and are susceptible to stress concentration, thereby contributing to an increase in the polishing rate. Furthermore, the rotational movement of the constricted silica particle linked bodies increases the dynamic contact area with the polishing substrate, which also contributes to an increase in the polishing rate.

[0061] As in the case of the aforementioned linked compound of the present invention, it is preferable that a-b ≥ (b / 10) and c-b ≥ (b / 10) are satisfied.

[0062] As in the case of the linked particles of the present invention described above, it is preferable that one constricted silica particle linked particle contains two or more specific linking moieties.

[0063] <Number of connected silica primary particles> In the plurality of constricted silica particle linked bodies constituting at least a part of the particle group in the second dispersion of the present invention, the number of primary silica particles constituting one constricted silica particle linked body is 5 to 50 on average, and preferably 5 to 15 on average. If this number is less than 5, when the second dispersion of the present invention is used as an abrasive for polishing, the dynamic contact area with the object to be polished may not be sufficient and the desired polishing rate may not be achieved. On the other hand, if this number exceeds 50, when the second dispersion of the present invention is used as an abrasive for polishing, defects may occur.

[0064] The number of primary silica particles constituting one constricted silica particle linked unit among the plurality of constricted silica particle linked units constituting at least a part of the particle group in the second dispersion of the present invention is measured as follows. First, the particle group dispersed in the second dispersion of the present invention is observed under a scanning electron microscope at 200,000 magnifications to identify 200 particles containing the specific linking portion described above. Next, for each of the 200 identified particles, the number of silica primary particles that make up the particle is counted. Then, the average number of primary silica particles in each of the 200 particles is calculated, and the obtained value is regarded as the number.

[0065] <Average particle size of primary silica particles> The particle diameter of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a part of the particle group is 5 to 600 nm on average, preferably 5 to 400 nm, and more preferably 10 to 300 nm. If the average particle size is less than 5 nm, the constricted silica particle linked bodies contained in the second dispersion of the present invention tend to form clumps. As a result, in polishing applications, a sufficient polishing rate may not be achieved, possibly because stress concentration on the polishing substrate is not achieved. On the other hand, if the average particle size exceeds 600 nm, for example, in polishing applications, the contact area between the object to be polished (e.g., a substrate) and the constricted silica particle linked bodies contained in the second dispersion of the present invention may decrease, resulting in a decrease in the polishing rate, and scratches (linear marks) may be generated on the polished surface of the object to be polished.

[0066] The average particle size of the primary silica particles in the plurality of linked constricted silica particles constituting at least a part of the particle group is measured as follows. First, the particle group dispersed in the second dispersion of the present invention is observed under a scanning electron microscope at 200,000 magnifications to identify 100 particles containing the specific linking portion described above. Next, each of the 100 identified particles is observed under a transmission electron microscope at 200,000 magnifications to obtain a photograph or image. Next, for each of the 100 identified particles, the particle sizes of all the primary silica particles are measured by the same method as that for measuring the particle sizes of the primary silica particles in the linked composite of the present invention described above. Then, the particle diameters of all the primary silica particles contained in the identified 100 particles are obtained, and then these are simply averaged to determine the average particle diameter of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a part of the particle group.

[0067] <Particle size variation coefficient (CV value) of primary silica particles> The particle size coefficient of variation (CV value) of the primary silica particles in the plurality of constricted silica particle linked bodies that constitute at least a part of the particle group is, on average, 15 to 90%, preferably 15 to 60%, and more preferably 15 to 50%. The particle size coefficient of variation (CV value) is preferably within the above range for the same reasons as those for the linked body of the present invention described above.

[0068] The average particle size coefficient of variation (CV value) of the primary silica particles in the plurality of constricted silica particle linked bodies constituting at least a part of the particle group is measured as follows. As described above, the average particle size of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a part of the particle group is determined. Since the particle sizes of all primary silica particles contained in the 200 particles identified here are obtained, the standard deviation is calculated from these values. Then, this standard deviation is divided by the average value, and the obtained quotient is defined as the particle size coefficient of variation (CV value).

[0069] <Neck and its depth> The definition of the neck and its depth is the same as that in the connector of the present invention described above. As described above, in the second dispersion of the present invention, the particle diameter of the primary silica particles in the plurality of constricted silica particle linked bodies constituting at least a part of the particle group is 5 to 600 nm on average. When this average value is F' and the average value of the neck depth is Lm', Lm' is preferably F' / 3 or less, more preferably less than F' / 6, and even more preferably less than F' / 9. In this case, the bond strength between the two silica primary particles bonded to each other tends to be high, so when an object to be polished is polished using such a second dispersion of the present invention, the overall connected structure is maintained even under a polishing load, a large contact area is obtained between the particle group contained in the second dispersion of the present invention and the polishing substrate, and the desired polishing performance is easily obtained.

[0070] Here, a method for measuring the average neck depth Lm' will be described. First, the particle group dispersed in the second dispersion of the present invention is observed under a scanning electron microscope at 200,000 magnifications to identify 200 particles containing the specific linking portion described above. Next, each of the 200 identified particles is observed under a transmission electron microscope at 200,000 magnifications to obtain a photograph or image. Next, for each of the 200 identified particles, the depth of all the neck portions is measured in the same manner as in the case of the above-described conjugate of the present invention. Then, the average value Lm' is calculated by simply averaging the depths of all the necks contained in the identified 200 particles.

[0071] <Coefficient of variation of neck depth> After measuring the depth of all neck portions of each of the 200 identified particles using the above method, the standard deviation of the neck depth (Lm) is calculated from the measurements and divided by the average value Lm'. The coefficient of variation is preferably 0 to 40%, more preferably 0 to 35%, and even more preferably 0 to 30%. When a polishing object is polished using the second dispersion of the present invention, particle collapse during polishing is unlikely to occur, and the polishing rate is stable. In addition, the contact area between the particles contained in the second dispersion of the present invention and the polishing object is constant, increasing the polishing rate and making it difficult for defects such as scratches to occur.

[0072] <Cationic organic polymer component> The constricted silica particle linked bodies contained in the second dispersion of the present invention preferably contain a cationic organic polymer component inside, similar to the above-described linked bodies of the present invention. The reason for this is the same as that for the above-mentioned linker of the present invention.

[0073] At least a portion of the cationic organic polymer component encapsulated in the constricted silica particle linked bodies may migrate to the second dispersion of the present invention.

[0074] Whether or not the constricted silica particle linked bodies contained in the second dispersion of the present invention encapsulate a cationic organic polymer component therein depends on the following criteria, similar to the above-described constricted silica particle linked bodies of the present invention: This can be confirmed by measuring the chemical oxygen demand (COD) using potassium permanganate. The chemical oxygen demand (COD) by potassium permanganate is measured in the same manner as in the case of the conjugate of the present invention. When it is not less than a specific value, it is assumed that the enclosed silica particle conjugate contained in the second dispersion of the present invention contains it inside.

[0075] The form (three-dimensional structure, type, functional groups that may be contained, weight average molecular weight, etc.) of the cationic organic polymer component that the enclosed silica particle conjugate contained in the second dispersion of the present invention may contain may be the same as that of the conjugate of the present invention described above. The specific method for the weight average molecular weight of the cationic organic polymer component is also the same as that of the conjugate of the present invention described above.

[0076] <Ratio of Ca, Mg, Al and Fe> The particle group (including the enclosed silica particle conjugate) contained in the second dispersion of the present invention may contain at least one selected from the group consisting of Ca, Mg, Al and Fe. However, the total content of Ca, Mg, Al and Fe in the particle group contained in the second dispersion of the present invention is preferably 150 ppm or less, more preferably 50 ppm or less, and even more preferably 25 ppm or less. ]>Further, the Ca content in the particle group contained in the second dispersion of the present invention is preferably 10 ppm or less. Further, the Mg content in the particle group contained in the second dispersion of the present invention is preferably 10 ppm or less. Further, the Al content in the particle group contained in the second dispersion of the present invention is preferably 60 ppm or less. Further, the Fe content in the particle group contained in the second dispersion of the present invention is preferably 20 ppm or less.

[0077] The measuring methods of these components are as follows. First, for the second dispersion of the present invention, the solid content concentration is adjusted to 20% by mass to obtain a sample for measurement. Next, 1 g of the sample is precisely weighed into a platinum dish. Next, add 3 mL of phosphoric acid, 5 mL of nitric acid, and 10 mL of hydrofluoric acid, heat on a sand bath, and once it has dried, add a small amount of water and 50 mL of nitric acid to dissolve it, place it in a 100 mL measuring flask, and add water to make it 100 mL. Next, 10 mL of the solution is taken from the 100 mL solution and transferred to a 20 mL measuring flask. This operation is repeated five times to obtain five 10 mL aliquots. These are then used to perform measurements using the standard addition method on an ICP plasma optical emission spectrometer (for example, SII, model SPS5520). Next, a blank is measured in the same manner, and the blank is subtracted to obtain the measured value for each element. Next, from the above measured values, the mass ratio of each element (Ca, Mg, Al, and Fe) contained per unit mass of silica fine particles contained in the particle-linked silica fine particle dispersion is determined.

[0078] In the constricted silica particle linked bodies contained in the second dispersion of the present invention, the primary silica particles are directly bonded to each other. For example, they are bonded by chemical bonds such as siloxane bonds. In other words, the primary silica particles are not bonded to each other by binder components such as CaO, MgO, Al2O3, and Fe2O3. If the constricted silica particle linked bodies contained in the second dispersion of the present invention do not contain CaO, MgO, Al2O3, Fe2O3, etc., when a dispersion in which particle groups containing such linked bodies are dispersed in a dispersion medium is used for polishing semiconductor devices such as semiconductor substrates and wiring boards, there is little risk of metal contamination problems caused by these binder components occurring.

[0079] The proportion (number ratio) of constricted silica particle links having specific linking moieties in the particle group in the second dispersion of the present invention is preferably 10 to 100%, more preferably 30 to 100%, and even more preferably 50 to 100%. This abundance ratio (number ratio) is calculated by observing the particle group at 200,000 magnification using a scanning electron microscope and determining whether or not 200 randomly selected particles correspond to constricted silica particle linked bodies containing specific linking portions.

[0080] The dispersion medium in the second dispersion of the present invention is not particularly limited, and may be the same as the dispersion medium in the first dispersion of the present invention.

[0081] The average particle size of the particle groups in the second dispersion of the present invention measured by dynamic light scattering is 50 to 600 nm, preferably 60 to 400 nm, and more preferably 70 to 300 nm.

[0082] This average particle size is measured by the same method as the average particle size of the particle group in the first dispersion of the present invention, which is measured by dynamic light scattering.

[0083] The solid content of the second dispersion of the present invention is preferably 2 to 50% by mass, more preferably 5 to 30% by mass. Within this range, sedimentation of particles is unlikely to occur over time, and storage stability is excellent. If the solids concentration is too high, particle aggregation and subsequent sedimentation are likely to occur. In this case, when the second dispersion of the present invention is applied to polishing applications, the polishing rate and polishing efficiency may be reduced. Furthermore, during the process of storing or supplying the polishing abrasive dispersion for polishing processing, the polishing abrasive dispersion adhering to the inner wall of the container or supply device easily dries and becomes agglomerates, which may be mixed back into the polishing abrasive dispersion and cause scratches during the polishing processing. If the solid content concentration is too low, the second dispersion of the present invention will need to be concentrated in order to be used for various purposes.

[0084] Here, the solid content concentration in the second dispersion of the present invention is measured by the same method as the solid content concentration in the first dispersion of the present invention described above.

[0085] <Polishing composition> The dispersion of the present invention itself, a dispersion to which various components have been added, or a liquid containing the dispersion of the present invention can be used as a polishing composition. The polishing composition may contain one or more components selected from a polishing accelerator, a surfactant, a hydrophilic compound, a heterocyclic compound, a pH adjuster, and a pH buffer.

[0086] Examples of the polishing accelerator include acids such as sulfuric acid, nitric acid, phosphoric acid, oxalic acid, and hydrofluoric acid, as well as the sodium salts, potassium salts, and ammonium salts of these acids, and mixtures thereof. In the case of a polishing composition containing such a polishing accelerator, when polishing a workpiece made of multiple components, the polishing rate of a specific component of the workpiece can be accelerated, thereby ultimately obtaining a flat polished surface.

[0087] When the polishing composition contains a polishing accelerator, the content thereof is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less. Surfactant and / or Hydrophilic Compound: In order to improve the dispersibility and stability of the polishing composition, a cationic, anionic, nonionic, or amphoteric surfactant or hydrophilic compound can be added.

[0088] Both the surfactant and the hydrophilic compound have the effect of reducing the contact angle with the polished surface and promoting uniform polishing. The surfactant and / or hydrophilic compound can be selected from the following group, for example:

[0089] Anionic surfactants include carboxylates, sulfonates, sulfates, and phosphates. Carboxylate salts include soaps, N-acylamino acid salts, polyoxyethylene or polyoxypropylene alkyl ether carboxylates, and acylated peptides. Sulfonates include alkyl sulfonates, alkylbenzene and alkylnaphthalene sulfonates, naphthalene sulfonates, sulfosuccinates, α-olefin sulfonates, and N-acylsulfonates. Sulfate salts include sulfated oils, alkyl sulfates, alkyl ether sulfates, polyoxyethylene or polyoxypropylene alkyl allyl ether sulfates, and alkylamide sulfates. Phosphate salts include alkyl phosphates, polyoxyethylene or polyoxypropylene alkyl allyl ether phosphates, and the like.

[0090] Examples of cationic surfactants include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium chloride salts, benzethonium chloride, pyridinium salts, and imidazolinium salts. Examples of amphoteric surfactants include carboxybetaine type, sulfobetaine type, aminocarboxylate salts, imidazolinium betaine, lecithin, and alkylamine oxide.

[0091] Examples of nonionic surfactants include ether type, ether ester type, ester type, and nitrogen-containing type, and examples of ether type surfactants include polyoxyethylene alkyl and alkylphenyl ethers, alkylarylformaldehyde condensed polyoxyethylene ethers, polyoxyethylene polyoxypropylene block polymers, and polyoxyethylene polyoxypropylene alkyl ethers. Examples of ether ester type surfactants include polyoxyethylene ethers of glycerin esters, polyoxyethylene ethers of sorbitan esters, and polyoxyethylene ethers of sorbitol esters. Examples of ester type surfactants include polyethylene glycol fatty acid esters, glycerin esters, polyglycerin esters, sorbitan esters, propylene glycol esters, and sucrose esters. Examples of nitrogen-containing surfactants include fatty acid alkanolamides, polyoxyethylene fatty acid amides, and polyoxyethylene alkylamides. Other examples include fluorine-based surfactants.

[0092] The surfactant is preferably an anionic surfactant or a nonionic surfactant, and the salt includes ammonium salt, potassium salt, sodium salt, etc., with ammonium salt and potassium salt being particularly preferred.

[0093] Further, other surfactants, hydrophilic compounds, etc. include esters (glycerin esters, sorbitan esters, alanine ethyl esters, etc.), ethers (polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol alkyl ethers, polyethylene glycol alkenyl ethers, alkyl polyethylene glycols, alkyl polyethylene glycol alkyl ethers, alkyl polyethylene glycol alkenyl ethers, alkenyl polyethylene glycols, alkenyl polyethylene glycol alkyl ethers, alkenyl polyethylene glycol alkenyl ethers, polypropylene glycol alkyl ethers, polypropylene glycol alkenyl ethers, alkyl polypropylene glycols, alkyl polypropylene glycol alkyl ethers, alkyl polypropylene glycol alkenyl ethers, and alkenyl polypropylene glycols, etc.), polysaccharides (alginic acid, pectinic acid, carboxymethylcellulose, curdlan, pullulan, etc.), amino acid salts (glycine ammonium salt, glycine sodium salt ... Polycarboxylic acids and their salts (polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, ammonium polymethacrylate, sodium polymethacrylate, polyamic acid, polymaleic acid, polyitaconic acid, polyfumaric acid, poly(p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, ammonium polyacrylate, sodium polyacrylate, polyamic acid, ammonium polyamic acid, sodium polyamic acid, and polyglyoxylic acid, etc.), vinyl polymers (polyvinyl alcohol, etc.), alcohol, polyvinylpyrrolidone and polyacrolein, etc.), sulfonic acids and their salts (ammonium methyl taurate, sodium methyl taurate, sodium methyl sulfate, ethyl ammonium sulfate, butyl ammonium sulfate, sodium vinyl sulfonate, sodium 1-allylsulfonate, sodium 2-allylsulfonate, sodium methoxymethylsulfonate, ammonium ethoxymethylsulfonate, sodium 3-ethoxypropylsulfonate, etc.), and amides (propionamide, acrylamide,methylurea, nicotinamide, succinamide, sulfanilamide, etc.

[0094] When the substrate to be polished is a glass substrate or the like, any surfactant can be suitably used. However, when the substrate is a silicon substrate for a semiconductor integrated circuit or the like, and the influence of contamination by alkali metals, alkaline earth metals, halides, or the like must be avoided, it is desirable to use an acid or ammonium salt surfactant.

[0095] When the polishing composition contains a surfactant and / or a hydrophilic compound, the total content thereof is preferably 0.001 g or more and 10 g or less, more preferably 0.01 g or more and 5 g or less, and particularly preferably 0.1 g or more and 3 g or less, per liter of the polishing composition.

[0096] The content of the surfactant and / or hydrophilic compound is preferably 0.001 g or more per liter of the polishing composition in order to obtain a sufficient effect, and is preferably 10 g or less in order to prevent a decrease in the polishing rate.

[0097] The surfactant or hydrophilic compound may be used alone or in combination with two or more kinds.

[0098] When the polishing composition contains a metal, it may contain a heterocyclic compound to form a passivation layer or dissolution-inhibiting layer on the metal and thereby inhibit erosion of the substrate. Here, a "heterocyclic compound" refers to a compound having a heterocycle containing one or more heteroatoms. A heteroatom refers to an atom other than a carbon atom or a hydrogen atom. A heterocycle refers to a cyclic compound containing at least one heteroatom. A heteroatom refers only to atoms that form part of the ring system of a heterocycle, and does not refer to atoms that are external to the ring system, separated from the ring system by at least one non-conjugated single bond, or that are part of a further substituent of the ring system. Preferred heteroatoms include, but are not limited to, nitrogen, sulfur, oxygen, selenium, tellurium, phosphorus, silicon, and boron. Examples of heterocyclic compounds that can be used include imidazole, benzotriazole, benzothiazole, and tetrazole. More specific examples include 1,2,3,4-tetrazole, 5-amino-1,2,3,4-tetrazole, 5-methyl-1,2,3,4-tetrazole, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diamino-1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, and 3,5-diamino-1,2,4-triazole, but are not limited to these.

[0099] When a heterocyclic compound is incorporated into a polishing composition, the content is preferably 0.001 mass% or more and 1.0 mass% or less, more preferably 0.001 mass% or more and 0.7 mass% or less, and even more preferably 0.002 mass% or more and 0.4 mass% or less.

[0100] In order to enhance the effects of the above-mentioned additives, the pH of the polishing composition can be adjusted by adding an acid or a base as necessary.

[0101] When adjusting the pH of the polishing composition to 7 or higher, an alkaline pH adjuster is used. Preferably, sodium hydroxide, aqueous ammonia, ammonium carbonate, or an amine such as ethylamine, methylamine, triethylamine, or tetramethylamine is used.

[0102] When the polishing composition is adjusted to a pH of less than 7, an acidic pH adjuster is used. For example, hydroxy acids such as lactic acid, citric acid, malic acid, tartaric acid, and glyceric acid are used.

[0103] To maintain the pH value of the polishing composition constant, a pH buffer may be used, such as phosphates and borates such as ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and ammonium tetraborate tetrahydrate, or organic acids.

[0104] A solvent can be used for the polishing composition as needed. Water is usually used as the solvent, but alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol can be used as needed, and water-soluble organic solvents such as ethers, esters, and ketones can also be used. A mixed solvent consisting of water and an organic solvent can also be used.

[0105] The concentration of abrasive particles in the polishing composition is preferably in the range of 0.5% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 30% by mass or less. If the concentration is less than 0.5% by mass, depending on the type of substrate or insulating film, the concentration may be too low, resulting in a slow polishing rate and productivity problems. If the concentration of abrasive particles exceeds 50% by mass, the stability of the abrasive becomes insufficient, and the polishing rate and polishing efficiency do not improve further. In addition, dried matter may be generated and adhered during the process of supplying the dispersion liquid for polishing treatment, which may cause scratches.

[0106] <Production Method of the Present Invention> The manufacturing method of the present invention will be described. The manufacturing method of the present invention includes a preparation step and an addition step.

[0107] <Preparation process> In the preparation step, dispersions in which two types of silica primary particles having an average particle size difference of 10% or more are dispersed are prepared. For example, a dispersion liquid of silica primary particles having an average particle size α and a dispersion liquid of silica primary particles having an average particle size β are prepared. The dispersion in which the two types of silica primary particles are dispersed may be, for example, a conventionally known silica sol.

[0108] Here, the average particle size refers to a value measured using a scanning electron microscope (SEM) which will be described next. First, a scanning electron microscope (SEM) was used to measure the size of a given area of ​​a silica primary particle at a magnification of 3000x, with a field of view of 1.1 × 10 -3 mm 2 15 fields of view are photographed with an area of ​​100 mm. Then, for all primary silica particles contained in each individual image photographed in each field of view, the point on the image where the diameter is longest is taken as the major axis, and the length of that major axis is taken as the major diameter (DL). A point is also determined on the major axis that divides the major axis in half, and two points where a line perpendicular to this intersects with the outer edge of the primary silica particle are found. The length between these two points is measured and taken as the minor diameter (DS). The ratio of these (minor diameter / major diameter ratio) is then calculated. In this way, this ratio is calculated for all primary silica particles within the 15 fields of view, and a simple average is calculated, and the resulting value is taken as the average particle diameter.

[0109] The average particle diameters of the two prepared dispersions of primary silica particles differ by 10% or more. For example, when a dispersion of silica primary particles with an average particle size α and a dispersion of silica primary particles with an average particle size β are prepared, if α<β, then β / α will be 1.1 or more.

[0110] In this way, in the preparation step, two types of silica primary particles with an average particle size difference of 10% or more are prepared, and it is preferable that one of the two types of silica primary particle dispersions has an average particle size of 20 to 300 nm, and it is also preferable that the other of the two types of silica primary particle dispersions has an average particle size of 5 to 100 nm.

[0111] Furthermore, the mass ratio of the silica primary particles in one (large particles) to the other (small particles) of the dispersions of the two types of silica primary particles is preferably 100 parts by mass: 10 to 200 parts by mass, and more preferably 100 parts by mass: 20 to 100 parts by mass.

[0112] In the preparation step, these two types of silica primary particles are prepared and mixed to obtain a preparatory dispersion.

[0113] Here, a dispersion of primary silica particles having a different average particle size (third dispersion) may be added to the preparatory dispersion.

[0114] The concentrations of Ca, Mg, Al and Fe contained in the silica primary particles contained in the preparatory dispersion are preferably as follows, in terms of the mass of Ca, Mg, Al and Fe per unit mass of silica fine particles. Ca: 25ppm or less Mg: 25ppm or less Al: 150ppm or less Fe: 50ppm or less These contents are values ​​measured using a conventionally known inductively coupled plasma (ICP) emission spectrometer.

[0115] The SiO2 concentration in the preparatory dispersion is preferably 1.5 to 30 mass %, more preferably 4 to 18 mass %, in which case the primary silica particles contained therein tend to be easily linked together.

[0116] The preparatory dispersion may be completely free of Na. As a method for removing Na from the preparative dispersion, Na was removed using a cation exchange resin.+ ions to H + ion exchange method. Examples of cation exchange resins include strong acid cation exchange resins and weak acid cation exchange resins, and include resins having a structure substituted with -SO3H or -COOH.

[0117] The pH value of the preparatory dispersion may be within a range in which the dispersion of silica primary particles is stable. For example, the pH may be 2 to 12. pH adjustment can be performed using, for example, Na + This can be done by ion exchange.

[0118] The prepared dispersion may contain a pH buffer and / or a pH adjuster. As the pH buffer, it is desirable to use a known inorganic or organic pH buffer.

[0119] Examples of pH buffers include ammonium acetate, sodium acetate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, trisodium phosphate, tripotassium phosphate, disodium phosphate, dipotassium phosphate, sodium borate, potassium borate, sodium tetraborate (borax), potassium tetraborate, and ammonium hydroxide, etc. Among these, ammonium acetate or sodium acetate is particularly preferred.

[0120] As the pH adjuster, it is desirable to use a known inorganic or organic pH adjuster. Examples of pH adjusters include acids such as acetic acid, formic acid, carbonic acid, hydrochloric acid, nitric acid, phosphoric acid, hypophosphorous acid, phosphorous acid, phosphonic acid, sulfuric acid, boric acid, hydrofluoric acid, orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, metaphosphoric acid, and hexametaphosphoric acid. Examples of the base include alkali metal hydroxides such as potassium hydroxide, alkaline earth metal hydroxides, ammonia, etc. Among these, potassium hydroxide or ammonia is preferred because of its availability.

[0121] The resulting preparatory dispersion is preferably heated before being subjected to the next addition step. The preparatory dispersion liquid is preferably heated after the pH has been adjusted to the above range by adding the pH buffer material and / or pH adjuster, to a liquid temperature of 40°C to 98°C. Heating the mixture makes it easier for SiO2 bonds to form between adjacent primary silica particles, facilitating the production of connected particles. If the liquid temperature is too high, the primary silica particles tend to aggregate.

[0122] After the temperature of the preparatory dispersion is adjusted as described above, it is preferable to keep the dispersion for 0.5 to 64 hours. This is because the linking reaction of the primary silica particles proceeds. If the holding time is too long, it is not economically preferable.

[0123] <Addition process> In the adding step, a cationic organic polymer component is added to the preparatory dispersion liquid obtained as described above.

[0124] It is preferable to heat the preparatory dispersion to 40 to 98°C and then add the cationic organic polymer component.

[0125] The cationic organic polymer component may be the same as the cationic organic polymer component that may be encapsulated in the aforementioned linker of the present invention. The configuration of the cationic organic polymer component (steric structure, type, functional groups that may be contained, weight-average molecular weight, etc.) may be the same as that of the aforementioned linker of the present invention. The method for determining the weight-average molecular weight of the cationic organic polymer component is the same as that for the above-described linker of the present invention.

[0126] The amount of cationic organic polymer component added is not particularly limited, but when the mass (g) of silica in terms of SiO2 contained in the preparatory dispersion is WS1 and the amount (mass (g)) of the cationic organic polymer component added thereto is WA, it is preferable that 0.01≦WA / WS1≦0.3 is satisfied, and it is more preferable that 0.015≦WA / WS1≦0.07 is satisfied. . If WA / WS1 is within the above range, the silica primary particles tend to be easily linked together. If WA / WS1 is too high, the particles tend to be easily aggregated.

[0127] The pH after the total amount of the cationic organic polymer component has been added is preferably in the range of 9.0 to 12.0.

[0128] In the adding step, it is preferable that after the cationic organic polymer component is added to the preparatory dispersion, a silicic acid solution is further added to grow the neck portion.

[0129] It is preferable to add the silicic acid solution after adjusting the pH of the solution obtained by adding the cationic organic polymer component to the preparatory dispersion to 10.0 or higher. The pH can be adjusted by adding an alkaline component such as ammonia or water glass.

[0130] The silica concentration (SiO2 equivalent) in the liquid obtained by adding the cationic organic polymer component to the preparatory dispersion is preferably 1 to 30 mass %.

[0131] The amount of silica liquid to be added is not particularly limited, but when the mass (g) of silica in terms of SiO2 contained in the preparatory dispersion is WS2 and the mass (g) of silica in terms of SiO2 in the added silica liquid is WF, it is preferable that 0.01≦WF / WS2≦20 be satisfied. Within this range, when the dispersion of linked constricted silica particles obtained by the production method of the present invention is used in a polishing abrasive, desired polishing properties are likely to be obtained. If the WF / WS2 ratio is too low, the desired polishing properties tend to be difficult to obtain, possibly due to insufficient growth of the linkages between the silica primary particles. On the other hand, if the WF / WS2 ratio is too high, the shape of the silica particles contained in the dispersion of linked constricted silica particles obtained by the production method of the present invention tends to approach spheres, making it difficult to maintain the linked shape.

[0132] In the addition step, the temperature of the liquid after the cationic organic polymer component is added to the preparatory dispersion and the silicic acid liquid is further added is preferably 70 to 98°C.

[0133] The silicic acid solution is preferably an acidic silicic acid solution. Acidic silicic acid solution is prepared by dissolving alkali metal silicate (such as sodium silicate) in water and exchanging the alkali metal ions for hydrogen ions. One method for exchanging alkali metal ions for hydrogen ions is to use a cation exchange resin. Acidic silicic acid solution can be used as long as it has a pH of 6 or less. The SiO2 concentration of the acidic silicic acid solution can be 1% by mass or more and 6% by mass or less. If the SiO2 concentration is less than 1% by mass, a large amount of acidic silicic acid solution must be added, which is uneconomical. If the SiO2 concentration is 6% by mass or more, the acidic silicic acid solution itself becomes unstable, which is undesirable. The SiO2 concentration is more preferably 1% by mass or more and 5% by mass or less.

[0134] In the production method of the present invention, it is preferable not to use a conventionally known inorganic flocculant. The use of an organic polymer component, particularly an organic polymer component containing a cationic functional group, allows for control of the surface charge of the silica primary particles. This allows for the production of constricted silica particle linked bodies with a desired morphology without the use of an inorganic flocculant. Furthermore, compared with silica fine particles obtained by conventional methods, the content of metal impurities can be reduced, which is particularly advantageous for semiconductor polishing applications, since it can prevent contamination of the polishing substrate or polishing equipment. The inventors interpret the mechanism of the present invention as follows. In the preparation step of the manufacturing method of the present invention, the organic polymer component added to the preparatory dispersion in which the silica primary particles are dispersed partially or entirely coats the surfaces of the silica primary particles, and a portion of the cationic organic polymer component is also present in the solvent. The cationic organic polymer component acts to reduce the repulsive force between the silica primary particles, reducing the absolute value of their surface potential and making them more unstable and prone to aggregation. Furthermore, when heated in the preparation step, association of the silica primary particles coated with the cationic organic polymer component progresses, producing an aggregate of silica primary particles having a branched and three-dimensional structure (particle-linked silica fine particles having a branched and three-dimensional structure). In the addition step of the production method of the present invention, when silicic acid is added under predetermined conditions to the silica primary particle association having the branched and three-dimensional structure, particle growth proceeds while filling necks between adjacent silica fine particles in the silica primary particle association having the branched and three-dimensional structure. When silicic acid is added to the silica primary particle aggregates under predetermined conditions in this manner, the silica component is deposited on the cationic organic polymer component adsorbed on the surfaces of the silica primary particles, resulting in the formation of constricted silica particle linked bodies in which the organic component derived from the cationic organic polymer component is encapsulated inside the particles. Meanwhile, as the cationic organic polymer component present in the dispersion medium is adsorbed to the particle surface during particle growth, an increase in surface potential occurs, leading to secondary association, in which association of primary silica particles progresses even during particle growth. Therefore, the development of a branched and three-dimensional structure is further promoted in the linked silica particles of the present invention and the constricted silica particle linked silica particles contained in the second dispersion of the present invention. It is not necessary for all of the cationic organic polymer component to be encapsulated in the linked silica particles of the present invention or the constricted silica particle linked silica particles contained in the second dispersion of the present invention; the cationic organic polymer component may also be adsorbed to the particle surface. [Example]

[0135] [Analysis methods used in examples and comparative examples] The following analyses were carried out on the dispersions (1) to (3) of linked constricted silica particles obtained in Examples 1 to 3 described below.

[0136] <About single-particle constricted silica particle linkages> [I] One constricted silica particle linked particle contained in each of the constricted silica particle linked particles (1) to (3) was observed under a transmission electron microscope or a scanning electron microscope at 200,000 magnification as described above, and the number of linked particles was counted. Specifically, images or photographs of each of the linked constricted silica particle dispersions [solid content concentration: 0.1% by mass] were taken at 200,000 magnifications using a scanning electron microscope [ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation)], and the number of linked silica primary particles in the linked constricted silica particle mixtures that satisfied the following requirements was measured. Requirements: Three primary silica particles with particle sizes a, b, and c are connected in this order, and have a specific connecting part that satisfies a>b and c>b.

[0137] [II] The average particle size of the primary silica particles of one particle of linked constricted silica particles contained in each of the dispersions (1) to (3) was measured using the method described above with reference to FIG. 1. The transmission electron microscope used was an ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation).

[0138] [III] The particle size coefficient of variation (CV value) of the primary silica particles was measured using the method described above for one particle of linked constricted silica particles contained in each of the dispersions (1) to (3) of linked constricted silica particles. The transmission electron microscope used was an ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation).

[0139] The above analyses [I], [II] and [III] are carried out to confirm the presence of the conjugate of the present invention.

[0140] <Average particle size measured by dynamic light scattering> The average particle diameter of each of the constricted silica particle linked body dispersions (1) to (3) was measured by dynamic light scattering as described above. The particle size measurement device (laser particle analyzer) used was a Zeta Potential / Particle Size Measurement System ELSZ-1000 (measurement principle: dynamic light scattering, light source wavelength: 665.70 nm, cell: 10 mm square plastic cell) manufactured by Otsuka Electronics Co., Ltd. Specifically, the constricted particle-linked silica microparticle dispersion was diluted with 0.58% ammonia water to adjust the silica concentration to 1% by mass, and the silica was measured using the laser particle analyzer.

[0141] <Proportion (number ratio) of linked constricted silica particles in the particle group> For each of the constricted linked silica particle dispersions (1) to (3), the particle groups were observed at 200,000 magnifications using a scanning electron microscope, as described above, to determine the proportion (number ratio) of the constricted linked silica particles in the particle groups. The scanning electron microscope used was an ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation).

[0142] <In the case of the second dispersion of the present invention> For each of the constricted linked silica fine particle dispersions (1) to (3), the average particle size of the primary silica particles was determined by the method described above. The scanning electron microscope used was an ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation).

[0143] For each of the constricted linked silica particle dispersions (1) to (3), the average value of the particle size coefficient of variation (CV value) of the primary silica particles was determined by the method described above. The scanning electron microscope used was an ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation).

[0144] For each of the constricted linked silica particle dispersions (1) to (3), the average number of the silica primary particles constituting one constricted linked silica particle was determined by the method described above. The scanning electron microscope used was an ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation). Specifically, a 200,000-magnification image or photograph of each of the constricted silica particle dispersions [solid content concentration: 0.1% by mass] was prepared using a scanning electron microscope [ultra-high resolution field emission scanning electron microscope S-5500 (manufactured by Hitachi High-Technologies Corporation)], and the number of linked primary silica particles was measured for 100 randomly selected constricted silica particle linked particles from among the constricted silica particle linked particles satisfying the following requirements. The average value for the 100 particles was calculated, and this average value was defined as the average number of linked primary silica particles of the constricted silica particle linked particles contained in the constricted silica particle dispersion. Requirements: Three primary silica particles with particle sizes a, b, and c are connected in this order, and have a specific connecting part that satisfies a>b and c>b.

[0145] [Polishing test] Method for evaluating polishing characteristics for SiO2 insulating film (thickness 1 μm) substrate and method for preparing abrasive dispersion liquid for polishing [Preparation of abrasive dispersion for polishing] The particle-linked silica microparticle dispersion or silica microparticle dispersion obtained in each of the examples and comparative examples was diluted with ion-exchanged water to adjust the solid content to 1.0 mass %, and each was adjusted to pH 6.0 by adding an aqueous nitric acid solution (concentration 5%) to prepare abrasive grain dispersions for polishing. [Polishing test method] The substrate to be polished was an SiO2 insulating film (1 μm thick) substrate produced by thermal oxidation. This substrate was set in a polishing machine (NF300, manufactured by Nanofactor Co., Ltd.), and polishing was performed using a polishing pad (Nitta Haas "IC-1000 / SUBA400 concentric type") with a substrate load of 0.04 MPa, a table rotation speed of 90 rpm, and a polishing abrasive dispersion supplied at a rate of 200 mL / min for 1 minute. The weight change of the substrate before and after polishing was then determined to calculate the polishing rate (nm / min). The surface smoothness (surface roughness [Ra]) of the polishing substrate was also measured using an atomic force microscope (AFM, Hitachi High-Tech Science Corporation). Since smoothness and surface roughness are roughly proportional, the surface roughness is listed in Table 1.

[0146] [Example 1] As dispersions in which two types of silica primary particles were dispersed, "Cataloid SI-45P" (manufactured by JGC Catalysts and Chemicals Co., Ltd., solid content concentration 40% by mass) and "Cataloid SI-50" (manufactured by JGC Catalysts and Chemicals Co., Ltd., solid content concentration 48% by mass) were prepared. The average particle diameter of the silica primary particles contained in these was measured by the method using the scanning electron microscope (SEM) mentioned above, and was found to be 45 nm for the former and 26 nm for the latter. Next, 1.4 g of Cataloid SI-45P was diluted with 33.5 g of pure water, and then 0.06 g of Cataloid SI-50 was added thereto to obtain a preparatory dispersion (1) with a solid content concentration of 1.6 mass %. Next, 5.0 g of a polyethyleneimine aqueous solution (concentration: 0.3% by mass) was added as a cationic organic polymer component to the resulting preparatory dispersion (1). The pH of the dispersion after the addition was 10.6. Next, the liquid to which the cationic organic polymer component had been added was heated and held at 98°C for 60 minutes. As a result, a dispersion liquid (1) of linked constricted silica particles was obtained.

[0147] The thus obtained dispersion liquid (1) of linked constricted silica particles was subjected to various analyses. As described above, observation at 200,000x magnification using a transmission electron microscope confirmed the presence of a constricted silica particle linkage having a portion constituting a specific linkage, with the particle diameters of three linked silica primary particles being 62 nm, 36 nm, and 60 nm, respectively. This specific linkage satisfies a-b ≥ (b / 10) and c-b ≥ (b / 10). It was also confirmed that this constricted silica particle linkage having a specific linkage further contains another specific linkage site. Furthermore, although the numerical values ​​differ, it was confirmed that there were multiple constricted silica particle linked bodies having portions corresponding to the specific linking portions. The analysis results are shown in Table 1. As shown in Table 1, it was confirmed that the constricted silica particle linked particle dispersion (1) corresponds to the first dispersion containing the linked particles of the present invention and the second dispersion of the present invention.

[0148] [Example 2] "Cataloid SI-45P" (manufactured by JGC Catalysts and Chemicals Co., Ltd., solid content concentration 40% by mass) and "Cataloid SI-40" (manufactured by JGC Catalysts and Chemicals Co., Ltd., solid content concentration 40% by mass) were prepared as dispersions in which two types of primary silica particles were dispersed. The average particle diameter of the primary silica particles contained in these dispersions was measured using the above-mentioned scanning electron microscope (SEM) method, and was found to be 45 nm for the former and 18 nm for the latter. Next, 86 g of Cataloid SI-45P was diluted with 3366 g of pure water, and then 5.83 g of Cataloid SI-40 was added thereto to obtain a preparatory dispersion (2) with a solid content concentration of 1.1 mass %. Next, 41 g of an aqueous sodium hydroxide solution (concentration: 4.86% by mass) was added to the resulting preparatory dispersion (2) to adjust the pH. The pH of the dispersion after the pH adjustment was 11.5. Next, 250 g of an aqueous solution of polyethyleneimine (concentration: 0.3%) was added as a cationic organic polymer component to the pH-adjusted preparatory dispersion (2). Next, the liquid to which the cationic organic polymer component had been added was heated and held at 90°C for 60 minutes. Thereafter, 321 g of an acidic silicic acid solution (SiO2 concentration: 4.55% by mass) was further added over 60 minutes. As a result, a dispersion liquid (2) of linked constricted silica particles (solid content concentration: 1.3%) was obtained.

[0149] The thus obtained dispersion liquid (2) of linked constricted silica particles was subjected to various analyses. As described above, observation at 200,000x magnification using a transmission electron microscope confirmed the presence of a constricted silica particle linkage having a portion constituting a specific linkage, with the particle diameters of three linked silica primary particles being 66 nm, 23 nm, and 64 nm, respectively. This specific linkage satisfies a-b ≥ (b / 10) and c-b ≥ (b / 10). It was also confirmed that this constricted silica particle linkage having a specific linkage further contains another specific linkage site. Furthermore, although the numerical values ​​differ, it was confirmed that there were multiple constricted silica particle linked bodies having portions corresponding to the specific linking portions. The analysis results are shown in Table 1. As shown in Table 1, it was confirmed that the constricted silica particle linked particle dispersion (2) corresponds to the first dispersion containing the linked particles of the present invention and the second dispersion of the present invention.

[0150] [Example 3] The same procedure as in Example 2 was carried out, except that the amount of "Cataloid SI-40" used was changed to 16.32 g. The thus obtained dispersion liquid (3) of linked constricted silica particles was subjected to various analyses. As described above, observation at 200,000x magnification using a transmission electron microscope confirmed the presence of a constricted silica particle linkage gb, which has three linked primary silica particles with particle diameters of 66 nm, 25 nm, and 61 nm, respectively, constituting a specific linking moiety. This specific linking moiety satisfies a-b ≥ (b / 10) and c-b ≥ (b / 10). It was also confirmed that this constricted silica particle linkage with a specific linking moiety further contains two additional specific linking sites. Furthermore, although the numerical values ​​differ, it was confirmed that there were multiple constricted silica particle linked bodies having portions corresponding to the specific linking portions. The analysis results are shown in Table 1. As shown in Table 1, it was confirmed that the constricted silica particle linked particle dispersion (3) corresponds to the first dispersion containing the linked particles of the present invention and the second dispersion of the present invention.

[0151] [Comparative Example 1] For silica fine particle dispersion "Cataloid SI-50" (average particle diameter 30 nm (SEM image analysis method), solid content 48 mass%, manufactured by JGC Catalysts and Chemicals Co., Ltd.), various measurements were carried out in the same manner as in Example 1. The analysis results are shown in Table 1.

[0152] Comparative Example 2 For silica fine particle dispersion "CATALOID SI-45P" (average particle diameter 50 nm (SEM image analysis method), solid content 40 mass%, manufactured by JGC Catalysts and Chemicals Co., Ltd.), various measurements were carried out in the same manner as in Example 1. The analysis results are shown in Table 1.

[0153] Comparative Example 3 3,986 g of ion-exchanged water was added to 300 g of fumed silica (AEROSIL50, manufactured by Nippon Aerosil Co., Ltd.), and the mixture was wet-disintegrated and pulverized using high-purity silica beads (manufactured by Daiken Chemical Industry Co., Ltd. and Ashizawa Finetech Co., Ltd., Bead Mill LMZ06) with a diameter of 0.25 mm. 4,286 g of a silica microparticle dispersion with a solid content of 7% by mass was obtained. Various measurements were carried out on the obtained silica microparticle dispersion in the same manner as in Example 1. The analytical results are shown in Table 1.

[0154] [Table 1]

Claims

1. A constricted silica particle linked body in which 5 to 50 silica primary particles are linked together, and neck portions are present at all of the linking points, and when the average particle diameter of the silica primary particles is F, the depth (Lm) of all of the neck portions is F / 3 or less, and the following requirements (A) to (C) are satisfied: (A) The average particle size of the silica primary particles is 5 to 600 nm. (B) The particle size coefficient of variation (CV value) of the silica primary particles is 15 to 90%. (C) Three of the silica primary particles having particle sizes a, b, and c are connected in this order to form a specific connecting portion that satisfies a>b and c>b.

2. The constricted silica particle linked structure according to claim 1 , further satisfying the following requirement (D): (D) a-b≧(b / 10) and c-b≧(b / 10).

3. The constricted silica particle linked structure according to claim 1 or 2, further satisfying the following requirement (E): (E) Contains two or more of the specific linking portions.

4. a particle group at least partly comprising the constricted silica particle linked bodies according to any one of claims 1 to 3, dispersed in a dispersion medium; The particle group has an average particle size of 50 to 600 nm as measured by dynamic light scattering.

5. 5. The dispersion of linked constricted silica particles according to claim 4, wherein the proportion (number ratio) of the linked constricted silica particles in the particle group is 10 to 100%.

6. The constricted silica particle linked dispersion liquid is obtained by dispersing in a dispersion medium a particle group at least partly made up of constricted silica particle linked bodies having specific linking parts in which three silica primary particles having particle diameters a, b, and c are linked in this order and satisfy the conditions a>b and c>b, and satisfies the following requirements [1] to [4]: [1] The average particle size of the primary silica particles in the plurality of linked constricted silica particles that constitute at least a part of the particle group is 5 to 600 nm. [2] The particle size coefficient of variation (CV value) of the primary silica particles in the plurality of linked constricted silica particles constituting at least a part of the particle group is 15 to 90% on average. [3] In the plurality of constricted silica particle linked bodies constituting at least a part of the particle group, the number of the silica primary particles constituting one constricted silica particle linked body is 5 to 50 on average, the 5 to 50 silica primary particles are linked together, neck portions are present at all of the linking points, and when the average particle diameter of the silica primary particles is F, the depth (Lm) of all of the neck portions is F / 3 or less. [4] The average particle size measured by dynamic light scattering is 50 to 600 nm.

7. The dispersion liquid of linked constricted silica particles according to claim 6, further satisfying the following requirement [5]: [5] The particle group contains the constricted silica particle linked bodies in an amount (number ratio) of 10 to 100%.

8. a preparation step of preparing dispersions in which two types of silica primary particles having an average particle size difference of 10% or more are dispersed, and mixing these dispersions to obtain a preparation dispersion; adding a cationic organic polymer component to the preparatory dispersion; a method for producing a dispersion of linked constricted silica particles, the method comprising the steps of:

9. In the adding step, 9. The method for producing a dispersion of linked constricted silica particles according to claim 8, wherein after the cationic organic polymer component is added to the preparatory dispersion, a silicic acid solution is further added to grow necks.

Images