Polishing method and method for manufacturing a semiconductor substrate, and a set of polishing compositions

Abstract

The present invention provides a means to reduce surface defects of a substrate after polishing. The present invention relates to a polishing method for a substrate, wherein the polishing method comprises a polishing process, wherein the polishing process comprises two or more polishing stages, wherein the substrate is polished by rotating the polishing plate while supplying a polishing composition to the contact surface of the substrate and a polishing pad installed on the polishing plate, and wherein the two or more polishing stages comprise a polishing stage 1 that polishes using a polishing composition S1 on the polishing plate, and a polishing stage 2 that polishes using a polishing composition S2 on the same polishing plate as the polishing stage 1 after the polishing stage 1, wherein the polishing composition S1 contains abrasive 1, water, and a water-soluble polymer having an abrasive adsorption parameter of 5 or more, and the polishing composition S2 contains abrasive 2, water, and a water-soluble polymer having an abrasive adsorption parameter of less than 5, and furthermore, does not contain the water-soluble polymer having an abrasive adsorption parameter of 5 or more in an amount of 0.005 mass% or more.

Description

Technology Field

[0001] The present invention relates to a polishing method, a method for manufacturing a semiconductor substrate, and a set of polishing compositions. Background Technology

[0002] The surface of semiconductor substrates, such as silicon wafers, and other substrates used as components of semiconductor products is generally finished into a high-quality mirror surface through a lapping process (rough polishing process) and a polishing process (precision polishing process). As a polishing method in the above polishing process, the chemical mechanical polishing method (CMP method) using a polishing slurry containing abrasive particles in a liquid is widely adopted. This polishing method is based on the combined action of mechanical polishing action by abrasive particles and chemical polishing action by components other than abrasive particles contained in the liquid, and it is known that a mirror surface with excellent smoothness and low defects can be obtained using this method.

[0003] In addition, in order to realize high integration and high speed of integrated circuits such as ULSI used in computers, the miniaturization of design rules for semiconductor devices is progressing year after year. Along with this, there is an increasing number of cases where even smaller surface defects adversely affect the performance of semiconductor devices, and the importance of managing nano-order defects, which were not previously a problem, is growing.

[0004] In recent years, there has been a demand for higher-quality surfaces for semiconductor substrates and other substrates such as silicon wafers, and various polishing compositions capable of meeting these demands have been examined. As such, Japanese Patent Publication No. 2017-183478 discloses a method for polishing a silicon wafer comprising a finishing polishing process, a pre-polishing process one step prior to the finishing polishing process, and a rinsing process for rinsing the silicon wafer after the pre-polishing process, which is located between the finishing polishing process and the pre-polishing process. In this method, the pre-polishing composition and the rinsing agent are selected such that the hydrophilic parameter of the rinsing agent used to rinse the silicon wafer in the rinsing process becomes smaller than the hydrophilic parameter of the pre-polishing composition used in the pre-polishing process. Furthermore, this document discloses that, according to this method, it is possible to achieve a high-quality polished surface on the silicon wafer after polishing by reducing haze and micro-defects. The problem to be solved

[0005] In recent years, the demand for reducing surface defects in semiconductor substrates, silicon wafers, and other substrates has been increasing. In response to this demand, the present invention aims to provide a means for reducing surface defects of a substrate after polishing. means of solving the problem

[0006] The above problem of the present invention can be solved by the following means:

[0007] It is a method for polishing a substrate, and

[0008] The above polishing method includes a polishing process, and

[0009] The polishing process comprises two or more polishing stages that polish the substrate by rotating the polishing plate while supplying a polishing composition to the contact surface of the substrate and a polishing pad installed on the polishing plate.

[0010] The above two or more grinding stages are,

[0011] A grinding step 1 that grinds using a grinding composition S1 on a grinding plate, and

[0012] After the above grinding step 1, the grinding step 2 is performed using a grinding composition S2 on the same grinding plate as the above grinding step 1, and

[0013] The above polishing composition S1 contains abrasive 1, water, and a water-soluble polymer having an abrasive adsorption parameter of 5 or more calculated by the steps of (1) to (4) below, and

[0014] The polishing composition S2 comprises abrasive particles 2, water, and a water-soluble polymer having an abrasive particle adsorption parameter of less than 5, and further comprises not containing a water-soluble polymer having an abrasive particle adsorption parameter of 5 or more in an amount of 0.005 mass% or more.

[0015] Polishing method:

[0016] (1) Prepare a test solution L containing 0.08 mass% of colloidal silica with an average primary particle size of 25 nm and an average secondary particle size of 50 nm, 0.004 mass% of a water-soluble polymer to be measured and 0.005 mass% of ammonia, with the remainder being water.

[0017] (2) Measure the total organic carbon concentration (TOC value) of the above test solution L, and set the obtained TOC value as the total organic carbon concentration W0 of the water-soluble polymer of the subject to measurement contained in the above test solution L, and

[0018] (3) The above test solution L is centrifuged at a rotational speed of 26,000 rpm for 30 minutes to separate it into a precipitate and a supernatant, and the TOC value of the supernatant is measured, and the obtained TOC value is set as the total organic carbon concentration W1 of the water-soluble polymer of the subject to measurement contained in the supernatant.

[0019] (4) Calculate the adsorption ratio of the water-soluble polymer of the measurement target using the following formula, and use this value as the particle adsorption parameter.

[0020]

[0021] In addition, the above problem of the present invention can also be solved by the following means:

[0022] It is a set of polishing compositions used in a method for polishing a substrate, and

[0023] The above polishing method includes a polishing process, and

[0024] The polishing process comprises two or more polishing stages that polish the substrate by rotating the polishing plate while supplying a polishing composition to the contact surface of the substrate and a polishing pad installed on the polishing plate.

[0025] The above two or more grinding stages are,

[0026] Grinding plate 1, which is ground on a grinding plate, and

[0027] After the above grinding step 1, it includes a grinding step 2 that is ground on the same grinding plate as the above grinding step 1, and

[0028] The above set of polishing compositions is,

[0029] A polishing composition S1 used in the polishing step 1, comprising abrasive particles 1, water, and a water-soluble polymer having an abrasive particle adsorption parameter of 5 or more calculated by the steps of (1) to (4) below, and

[0030] A polishing composition S2 used in the polishing step 2, comprising abrasive particles 2, water, and a water-soluble polymer having an abrasive particle adsorption parameter of less than 5, and also not comprising a water-soluble polymer having an abrasive particle adsorption parameter of 5 or more in an amount of 0.005 mass% or more.

[0031] A set of abrasive compositions comprising:

[0032] (1) Prepare a test solution L containing 0.08 mass% of colloidal silica with an average primary particle size of 25 nm and an average secondary particle size of 50 nm, 0.004 mass% of a water-soluble polymer to be measured and 0.005 mass% of ammonia, with the remainder being water.

[0033] (2) Measure the total organic carbon concentration (TOC value) of the above test solution L, and set the obtained TOC value as the total organic carbon concentration W0 of the water-soluble polymer of the subject to measurement contained in the above test solution L, and

[0034] (3) The above test solution L is centrifuged at 26,000 rpm for 30 minutes to separate it into a precipitate and a supernatant, and the TOC value of the supernatant is measured, and the obtained TOC value is set as the total organic carbon concentration W1 of the water-soluble polymer of the subject to measurement contained in the supernatant.

[0035] (4) Calculate the adsorption ratio of the water-soluble polymer of the measurement target using the following formula, and use this value as the particle adsorption parameter.

[0036]

[0037] Embodiments of the present invention are described below. Furthermore, the present invention is not limited to the following embodiments. Also, unless otherwise noted, operations and measurements of physical properties, etc. are performed under conditions of room temperature (range of 20°C or higher and 25°C or lower) and relative humidity of 40% RH or higher and 50% RH or lower.

[0038] Furthermore, in this specification, "(meth)acrylic acid" is a general term for acrylic acid and methacrylic acid. Likewise, "other compounds containing (meth)" is a general term for compounds having "meth" in their names and compounds not having "meth."

[0039] <Polishing Method>

[0040] One aspect of the present invention is a method for polishing a substrate, and

[0041] The above polishing method includes a polishing process, and

[0042] The polishing process comprises two or more polishing stages that polish the substrate by rotating the polishing plate while supplying a polishing composition to the contact surface of the substrate and a polishing pad installed on the polishing plate.

[0043] The above two or more grinding stages are,

[0044] A grinding step 1 that grinds using a grinding composition S1 on a grinding plate, and

[0045] After the above grinding step 1, the grinding step 2 is performed using a grinding composition S2 on the same grinding plate as the above grinding step 1, and

[0046] The above polishing composition S1 contains abrasive 1, water, and a water-soluble polymer having an abrasive adsorption parameter of 5 or more calculated by the steps of (1) to (4) described below, and

[0047] The present invention relates to a polishing method in which the polishing composition S2 contains abrasive particles 2, water, and a water-soluble polymer having an abrasive particle adsorption parameter of less than 5, and does not contain a water-soluble polymer having an abrasive particle adsorption parameter of 5 or more in an amount of 0.005 mass% or more (i.e., the concentration of the water-soluble polymer having an abrasive particle adsorption parameter of 5 or more in the polishing composition S2 is less than 0.005 mass% relative to the total mass of the polishing composition S2). According to the present embodiment, it is possible to provide a means for reducing surface defects of a substrate after polishing.

[0048] The inventors of the present invention surmise the mechanism by which the above problem can be solved by the present invention as follows. Water-soluble polymers with a large abrasive adsorption parameter are prone to adsorption onto silica, etc. First, in polishing step 1, a substrate is polished using a polishing composition containing a water-soluble polymer with a large abrasive adsorption parameter. At this time, the water-soluble polymer with a large abrasive adsorption parameter adsorbs onto the abrasive particles or the substrate, thereby protecting the substrate. From this, in polishing step 1, processing of the substrate can proceed while suppressing damage to the substrate. Subsequently, in polishing step 2, the substrate is polished using a polishing composition containing a water-soluble polymer with a small abrasive adsorption parameter. At this time, the water-soluble polymer with a small abrasive adsorption parameter does not adsorb much onto the abrasive particles and acts to remove the abrasive particles remaining on the substrate. From this, in polishing step 2, the substrate can be cleaned well. As a result, the substrate obtained after polishing using the polishing method related to the present invention has less damage and also has fewer abrasive particles remaining on the substrate, thereby significantly reducing surface defects. Furthermore, the above mechanism is based on conjecture, and its errors do not affect the technical scope of the present invention.

[0049] A method for polishing a substrate according to one embodiment of the present invention comprises a polishing process, wherein the polishing process comprises two or more polishing stages, wherein the substrate is polished by rotating the polishing plate while supplying a polishing composition to the contact surface of the substrate and a polishing pad installed on the polishing plate, and the two or more polishing stages comprise a polishing stage 1 that polishes using a polishing composition S1 on the polishing plate, and a polishing stage 2 that polishes using a polishing composition S2 on the same polishing plate as the polishing stage 1 after the polishing stage 1.

[0050] [Grinding Process]

[0051] Hereinafter, a polishing process included in a polishing method related to one embodiment of the present invention will be described.

[0052] A polishing device used in a polishing process related to one embodiment of the present invention and polishing conditions that can be employed in polishing stage 1 and polishing stage 2 are described.

[0053] As for the polishing device, there are no particular limitations, but for example, a general polishing device may be used that has a holding support (holder) for holding and supporting a substrate having a workpiece to be polished, a motor capable of changing the rotational speed, and a polishing plate capable of attaching a polishing pad (polishing cloth). For example, a single-sided polishing device or a double-sided polishing device may be used. Commercially available polishing devices are not particularly limited, but as a single-sided polishing device, for example, the sheet-fed polisher of the model “PNX 332B” manufactured by Okamoto Kosaku Kikai Seisakusho Co., Ltd.

[0054] When polishing an object to be polished using a single-sided polishing device, the object to be polished is held and supported using a holding support called a template, and a polishing plate with a polishing pad (polishing cloth) attached is pressed against one side of the object to be polished, and the polishing plate is rotated while supplying a polishing composition, thereby polishing one side of the object to be polished.

[0055] When polishing an object to be polished using a double-sided polishing device, the object to be polished is held and supported using a holding support called a carrier, and a polishing plate with a polishing pad (polishing cloth) attached is pressed against both sides of the object to be polished from both sides, and the two sides of the object to be polished are polished by rotating the polishing plates on both sides while supplying a polishing composition.

[0056] By using a polishing device such as these, a polishing composition is supplied to the contact surface between the substrate and the polishing pad installed on the polishing plate, and the substrate is polished by rotating the polishing plate.

[0057] As such, the polishing in the polishing process may be either single-sided polishing or double-sided polishing, but single-sided polishing is preferred.

[0058] As for the polishing pad, general non-woven fabric type, polyurethane type, suede type, etc., can be used without particular restrictions. A polishing pad with groove processing for collecting the polishing composition may also be used. Commercially available polishing pads are not particularly limited, but examples of non-woven fabric types include, for instance, the product name "FP55" manufactured by Fujibo Ehime Co., Ltd., and examples of suede types include, for instance, the product name "POLYPAS275NX" manufactured by Fujibo Ehime Co., Ltd.

[0059] Regarding grinding conditions, the desirable range varies depending on the purpose of grinding in each grinding stage. Therefore, grinding conditions are not particularly limited, and appropriate conditions can be adopted according to the purpose of grinding in each grinding stage.

[0060] Polishing is preferably performed by rotating the platen, and more preferably by moving the substrate and the platen relatively (e.g., rotational movement). The rotational speed of the platen and the rotational speed of the head (carrier, template) are not particularly limited, but are each independently, preferably 10 rpm (0.17 s -1 ) or more at 100rpm (1.67s -1 ) or less, and more preferably 20 rpm (0.33s -1 ) or more 60rpm(1s -1 ) or less, and more preferably 25 rpm (0.42 s -1 ) or more 55rpm(0.92s-1 ) is less than or equal to. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced, and production efficiency is further improved. In addition, the rotational speed of the platen (polishing plate) and the rotational speed of the head (carrier, template) may be the same or different.

[0061] Typically, the substrate is pressed by a polishing plate. The pressure (polishing load) at this time is not particularly limited, but is preferably 5 kPa or more and 30 kPa or less, and more preferably 10 kPa or more and 25 kPa or less. Within this range, surface defects occurring on the polished surface of the substrate are further reduced, and production efficiency is further improved.

[0062] Each polishing composition may be in a concentrated form before being supplied to the object to be polished. The concentrated form refers to the form of a concentrated liquid of the polishing composition, and can also be understood as the original liquid of the polishing composition. A polishing composition in such a concentrated form is advantageous in terms of convenience and cost reduction during manufacturing, distribution, and storage. The concentration ratio is not particularly limited and, for example, can be between 2 and 100 times in volume; typically, between 5 and 50 times, for example, between 10 and 40 times, is suitable. This concentrated liquid can be used in a manner where the polishing composition is prepared by diluting it at a desired timing and supplied to the object to be polished. Dilution can be performed, for example, by adding water to the concentrated liquid and mixing.

[0063] The supply speed of the polishing composition is not particularly limited as it can be appropriately selected according to the size of the polishing plate, but it is preferable that the supply amount be sufficient to cover the entire object to be polished. Considering economic efficiency, the supply speed of the polishing composition is more preferably 0.1 L / min or more and 5 L / min or less, and even more preferably 0.2 L / min or more and 2 L / min or less. Within this range, surface defects occurring on the polished surface of the substrate are further reduced, and production efficiency is further improved.

[0064] The method of supplying the abrasive composition is not particularly limited, and a method of continuous supply using a pump or the like (flow type) may be adopted.

[0065] There are no particular limitations on the holding temperature in the polishing device of the polishing composition, but from the perspective of the stability of the polishing speed and the effect of reducing surface defects occurring on the polished surface of the substrate, it is preferable that the temperature be 15°C or higher and 40°C or lower, and more preferable that the temperature be 18°C ​​or higher and 25°C or lower.

[0066] In addition, the polishing composition may be recovered after being used to polish an object, and after adjusting the composition by adding each component that may be included in the polishing composition as needed, it may be reused to polish an object.

[0067] In addition to polishing stage 1 and polishing stage 2, the polishing process may include other polishing stages as needed, and it is preferable to include other polishing stages. At this time, the positions of polishing stage 1 and polishing stage 2 are not particularly limited, but it is preferable that polishing stage 1 be one polishing stage before polishing stage 2, and more preferable that polishing stage 1 be one polishing stage before the final polishing stage, and that polishing stage 2 be the final polishing stage. The number of polishing stages included in the polishing process is preferably 2 or more and 10 or less, and more preferable that it is 3 or more and 6 or less.

[0068] In polishing stage 1 and polishing stage 2, the substrate is polished on the same polishing plate. Additionally, if the polishing process includes another polishing stage in addition to polishing stage 1 and polishing stage 2, in the other polishing stage, the substrate may be polished on the same polishing plate as polishing stage 1 and polishing stage 2, or may be polished on a different polishing plate than polishing stage 1 and polishing stage 2; however, in the other polishing stage, it is preferable that the substrate be polished on a different polishing plate than polishing stage 1 and polishing stage 2.

[0069] It does not matter what type of polishing is performed by polishing unit 1 and polishing unit 2. However, it is preferable that polishing unit 1 is a polishing unit that performs finishing polishing, and that polishing unit 2 is a polishing unit that performs rinse polishing. A polishing unit that performs finishing polishing refers to a polishing unit that more finely polishes a substrate roughly polished by a polishing unit that performs pre-polishing, such as preliminary polishing. Furthermore, a polishing unit that performs rinse polishing refers to a polishing unit that removes residue on the surface of a polished object by means of frictional force (physical action) by the polishing pad and the action of a polishing composition (rinse polishing composition), which is performed on a polishing platen equipped with a polishing pad. Accordingly, it is preferable that the polishing composition S2 is a rinse polishing composition.

[0070] From this, in a preferred embodiment of the present invention, the polishing process further comprises a polishing stage 1, a polishing stage 2, and one or more other polishing stages disposed before polishing stage 1, and furthermore, polishing stage 1 is a polishing stage one step prior to the final polishing stage and is a polishing stage that performs finishing polishing, and polishing stage 2 is a final polishing stage and is a polishing stage that performs rinse polishing.

[0071] The relationship between the polishing time of polishing stage 1 and the polishing time of polishing stage 2 is not particularly limited, but it is preferable that the polishing time in polishing stage 2 be shorter than the polishing time in polishing stage 1. In this case, surface defects occurring on the polished surface of the substrate are further reduced.

[0072] The polishing time of polishing step 1 is not particularly limited, but preferably greater than 80 seconds, more preferably greater than 100 seconds, and even more preferably greater than 150 seconds. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. Additionally, the polishing time of polishing step 1 is not particularly limited, but preferably less than 500 seconds, more preferably less than 300 seconds, and even more preferably less than 250 seconds. Within these ranges, production efficiency is improved.

[0073] The polishing time of polishing step 2 is not particularly limited, but preferably 1 second or more, more preferably 3 seconds or more, and even more preferably 5 seconds or more. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. In addition, the polishing time of polishing step 2 is not particularly limited, but preferably 80 seconds or less, more preferably 60 seconds or less, and even more preferably 40 seconds or less. Within these ranges, production efficiency is further improved.

[0074] The above polishing device and polishing conditions are merely described as a simple example, and may be outside the scope or the settings may be changed appropriately.

[0075] [Other processes]

[0076] The polishing method related to one embodiment of the present invention may further include other processes. Examples of other processes include, for instance, a cleaning process.

[0077] The cleaning process may be provided before, during, or after the polishing process. However, it is preferable to perform the cleaning treatment of the substrate during the cleaning process after the polishing process. The cleaning method in the cleaning process is not particularly limited, but as a preferred example, a first cleaning tank containing a cleaning solution and a second cleaning tank containing a cleaning solution are prepared, and the substrate polished in the polishing process is immersed in the first cleaning tank, then immersed in the second cleaning tank, and these immersions are repeated as needed. The immersion time in the first cleaning tank (the immersion time per immersion in the case of multiple immersions) is not particularly limited, but for example, it may be 1 minute or more and 10 minutes or less. In addition, the immersion time in the second cleaning tank (the immersion time per immersion in the case of multiple immersions) is not particularly limited, but may be 1 minute or more and 30 minutes or less. As for the cleaning solution, there are no particular limitations, but examples include pure water or a solution of NH4OH (29 mass%):H2O2 (31 mass%):deionized water (DIW) = 2:5.3:48 (volume ratio). Additionally, it is preferable that the cleaning solution in the first cleaning tank is a solution of NH4OH (29 mass%):H2O2 (31 mass%):deionized water (DIW) = 2:5.3:48 (volume ratio), and that the cleaning solution in the second cleaning tank is pure water. In this case, it is more preferable that the cleaning solution in the second cleaning tank is ultrapure water at 25°C. Immersion in the cleaning solution may be performed while the ultrasonic oscillator is in operation. Additionally, the temperature of the cleaning solution is not particularly limited, but it is preferable to have it in the range of 40°C to 80°C. Furthermore, after cleaning, it is preferable to dry the substrate using a known drying device such as a spin dryer.

[0078] [Abrasive composition]

[0079] Hereinafter, polishing compositions S1 and S2 used in a polishing method related to one embodiment of the present invention will be described. Additionally, polishing compositions S1 and S2 included in a set of polishing compositions related to another aspect of the present invention described later will be described.

[0080] (Georip)

[0081] Polishing composition S1 and polishing composition S2 contain abrasive particles. In this specification, the abrasive particles included in polishing composition S1 are referred to as abrasive particles 1, and the abrasive particles included in polishing composition S2 are referred to as abrasive particles 2. Abrasive particles 1 have the function of physically polishing the surface of a substrate. Abrasive particles 2 have the function of physically reducing surface residues on the substrate.

[0082] As for the abrasive particles, there are no particular limitations, but examples include inorganic particles, organic particles, and organic-inorganic composite particles. Specific examples of inorganic particles are not particularly limited, but examples include particles containing oxides such as silica, alumina, cerium oxide, chromium oxide, titanium dioxide, zirconium oxide, magnesium oxide, manganese dioxide, zinc oxide, Bengala, etc. (oxide particles); particles containing nitrides such as silicon nitride, boron nitride, etc. (nitride particles); particles containing carbides such as silicon carbide, boron carbide, etc. (carbide particles); particles containing diamond; particles containing carbonates such as calcium carbonate or barium carbonate, etc. Specific examples of organic particles are not particularly limited, but examples include particles containing polymethyl methacrylate (PMMA). In addition, particles containing one or more of the materials exemplified above may be used. Among these, silica is preferred. That is, abrasive particle 1 and abrasive particle 2 are preferably silica. Specific examples of silica include colloidal silica, fumed silica, and sol-gel silica. Among these, colloidal silica or fumed silica is preferred, and colloidal silica is more preferred, from the perspective of further reducing surface defects occurring on the polished surface of the substrate. It is preferable that abrasive particles 1 and 2 each include at least one type selected from the group consisting of the particles listed above.

[0083] The average primary particle size of the abrasive grains is not particularly limited, but is preferably 1 nm or larger, more preferably 5 nm or larger, even more preferably 10 nm or larger, and particularly preferably 20 nm or larger. Within these ranges, the polishing speed is improved. Additionally, the average primary particle size of the abrasive grains is not particularly limited, but is preferably 100 nm or smaller, more preferably 70 nm or smaller, even more preferably 50 nm or smaller, and particularly preferably 30 nm or smaller. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. The value of the average primary particle size of the abrasive grains is calculated from the specific surface area measured, for example, by the BET method. The measurement of the specific surface area of ​​the abrasive grains can be performed, for example, using the "FlowSorb II 2300" manufactured by Micromeritis. Examples of the range of the average primary particle size of desirable particles include 1 nm or more and 100 nm or less, 5 nm or more and 70 nm or less, 10 nm or more and 50 nm or less, 20 nm or more and 30 nm or less, but are not limited to these.

[0084] The relationship between the average primary particle size of abrasive 1 and the average primary particle size of abrasive 2 is not particularly limited, but it is preferable that the average primary particle size of abrasive 2 be less than or equal to the average primary particle size of abrasive 1. In addition, the ratio of the average primary particle size of abrasive 2 to the average primary particle size of abrasive 1 (average primary particle size of abrasive 2 / average primary particle size of abrasive 1) is not particularly limited, but is preferably 0.1 or more and 1 or less, more preferably 0.4 or more and 1 or less, even more preferably 0.8 or more and 1 or less, and particularly preferably 1. In these cases, surface defects occurring on the polished surface of the substrate can be further reduced.

[0085] The average secondary particle size of the abrasive grain is not particularly limited, but is preferably 10 nm or larger, more preferably 20 nm or larger, and even more preferably 30 nm or larger. Within these ranges, the polishing speed is improved. Additionally, the average secondary particle size of the abrasive grain is not particularly limited, but is preferably 200 nm or smaller, more preferably 150 nm or smaller, and even more preferably 100 nm or smaller. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. The value of the average secondary particle size of the abrasive grain can be measured, for example, by dynamic light scattering using the "UPA-UT151" model manufactured by Nikkiso Co., Ltd. Examples of the preferred range of the average secondary particle size of the abrasive grain include 10 nm or larger and 200 nm or smaller, 20 nm or larger and 150 nm or smaller, and 30 nm or larger and 100 nm or smaller, but are not limited to these.

[0086] The average aggregation degree of the abrasive grains is not particularly limited, but is preferably 1.2 or higher, more preferably 1.4 or higher, and even more preferably 1.5 or higher. In this specification, the average aggregation degree refers to a value obtained by dividing the value of the average secondary particle size of the abrasive grains by the value of the average primary particle size. Within these ranges, the polishing speed is further improved. In addition, the average aggregation degree of the abrasive grains is not particularly limited, but is preferably 4 or lower, more preferably 3.5 or lower, and even more preferably 3 or lower. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. Examples of the preferred range of the abrasive grain aggregation degree include 1.2 or higher and 4 or lower, 1.4 or higher and 3.5 or lower, 1.5 or higher and 3 or lower, etc., but are not limited thereto.

[0087] For the abrasives, commercially available products or synthetic products may be used. Additionally, for the abrasives, one type may be used alone or two or more types may be used in combination.

[0088] The concentration of abrasive grain 1 in the polishing composition S1 is not particularly limited, but is preferably 0.001 mass% or more with respect to the total mass of the polishing composition S1, more preferably 0.01 mass% or more, and even more preferably 0.05 mass% or more. Within these ranges, the polishing speed is improved. In addition, the concentration of abrasive grain 1 in the polishing composition S1 is not particularly limited, but is preferably 3 mass% or less with respect to the total mass of the polishing composition S1, more preferably 1 mass% or less, even more preferably 0.5 mass% or less, even more preferably 0.1 mass% or less, and particularly preferably 0.08 mass% or less. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. Examples of the range of concentration of abrasive particles 1 in a preferred polishing composition S1 include, but are not limited to, 0.001 mass% or more and 3 mass% or less, 0.01 mass% or more and 1 mass% or less, 0.05 mass% or more and 0.5 mass% or less, 0.05 mass% or more and 0.1 mass% or less, and 0.05 mass% or more and 0.08 mass% or less, based on the total mass of the polishing composition S1.

[0089] The concentration of abrasive particles 2 in the polishing composition S2 is not particularly limited, but is preferably 0.001 mass% or more and more preferably 0.01 mass% or more with respect to the total mass of the polishing composition S2. Within these ranges, the polishing speed is improved. In addition, the concentration of abrasive particles 2 in the polishing composition S2 is not particularly limited, but is preferably 3 mass% or less with respect to the total mass of the polishing composition S2, more preferably 1 mass% or less, even more preferably 0.5 mass% or less, even more preferably 0.1 mass% or less, and particularly preferably 0.08 mass% or less. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. Examples of the concentration of abrasive particles 2 in a preferred polishing composition S2 include, but are not limited to, 0.001 mass% or more and 3 mass% or less, 0.01 mass% or more and 1 mass% or less, 0.01 mass% or more and 0.5 mass% or less, 0.01 mass% or more and 0.1 mass% or less, and 0.01 mass% or more and 0.08 mass% or less, based on the total mass of the polishing composition S2.

[0090] From the above, in a preferred embodiment of the present invention, the concentration of abrasive grain 1 in the polishing composition S1 is 0.001 mass% or more and 3 mass% or less with respect to the total mass of the polishing composition S1, and the concentration of abrasive grain 2 in the polishing composition S2 is 0.001 mass% or more and 3 mass% or less with respect to the total mass of the polishing composition S2.

[0091] The relationship between the concentration of abrasive 2 in polishing composition S2 and the concentration of abrasive 1 in polishing composition S1 is not particularly limited, but it is preferable that the concentration of abrasive 2 in polishing composition S2 be less than or equal to the concentration of abrasive 1 in polishing composition S1. In addition, the ratio of the concentration of abrasive 2 in polishing composition S2 to the concentration of abrasive 1 in polishing composition S1 (concentration of abrasive 2 in polishing composition S2 / concentration of abrasive 1 in polishing composition S1) is not particularly limited, but is preferably 0.1 or more and 1 or less, and more preferably 0.4 or more and 1 or less. In these cases, surface defects occurring on the polished surface of the substrate can be further reduced. The above ratio can be, for example, 0.8 or more and 1 or less, and for example, 1.

[0092] (Water-soluble polymer)

[0093] Polishing composition S1 and polishing composition S2 contain a water-soluble polymer. In this specification, "water-soluble" means having a solubility in water (at 25°C) of 1 g / 100 mL or more, and "polymer" refers to a compound having a weight-average molecular weight of 1,000 or more. The weight-average molecular weight can be measured in polyoxyethylene equivalent by gel permeation chromatography (GPC). Specifically, the value measured by the method described in the examples may be adopted.

[0094] The polishing composition S1 contains a water-soluble polymer having an abrasive adsorption parameter (also referred to simply as "abrasive adsorption parameter" in this specification) of 5 or more, calculated by the steps of (1) to (4) described below. Additionally, it is preferable that the polishing composition S1 further contains a water-soluble polymer having an abrasive adsorption parameter of less than 5. Additionally, the polishing composition S2 contains a water-soluble polymer having an abrasive adsorption parameter of less than 5. Furthermore, the polishing composition S2 does not contain a water-soluble polymer having an abrasive adsorption parameter of 5 or more in an amount (concentration) of 0.005 mass% or more. That is, the concentration of the water-soluble polymer having an abrasive adsorption parameter of 5 or more in the polishing composition S2 is less than 0.005 mass% (less than 0.005 mass% relative to the total mass of the polishing composition S2). The water-soluble polymer having an abrasive adsorption parameter of 5 or more acts to protect the surface of the abrasive. Water-soluble polymers with a particle adsorption parameter of less than 5 act to reduce surface residue on the substrate.

[0095] The adsorption parameters of the water-soluble polymer particles can be calculated by the following steps (1) to (4):

[0096] (1) Prepare a test solution L containing 0.08 mass% of colloidal silica (PL-2 manufactured by Fuso Chemical Co., Ltd., average primary particle size 25 nm, average secondary particle size 50 nm), 0.004 mass% of a water-soluble polymer to be measured, and 0.005 mass% of ammonia, with the remainder being water.

[0097] (2) Measure the total organic carbon concentration (TOC value) of test solution L, and set the obtained TOC value as the total organic carbon concentration W0 [mass ppm] of the water-soluble polymer of the subject to measurement contained in test solution L, and

[0098] (3) Centrifugation treatment is performed on test solution L at 26,000 rpm for 30 minutes using a centrifuge such as the Avanti HP-30I manufactured by Beckmann Coulter Co., Ltd., to separate the precipitate and the supernatant, and the TOC value of the supernatant is measured, and the obtained TOC value is set as the total organic carbon concentration W1 [mass ppm] of the water-soluble polymer of the subject to measurement contained in the supernatant, and

[0099] (4) Calculate the adsorption ratio of the water-soluble polymer of the measurement target using the following formula, and use this value as the adsorption parameter of the abrasive particles.

[0100]

[0101] The total organic carbon concentration W0 [mass ppm] of the water-soluble polymer of the subject to measurement contained in test solution L and the total organic carbon concentration W1 [mass ppm] of the water-soluble polymer of the subject to measurement contained in the supernatant after centrifugation treatment of test solution L can be evaluated, for example, using the total organic carbon-based TOC-L manufactured by Shimadzu Seisakusho Co., Ltd.

[0102] In addition, details of the method for calculating the abrasive particle adsorption parameters are described in the examples.

[0103] It is thought that colloidal silica precipitates upon centrifugation of test solution L. Furthermore, the water-soluble polymer contained in the supernatant after centrifugation of test solution L is thought to be primarily the portion of the total water-soluble polymer that is not adsorbed onto the colloidal silica.

[0104] It is thought that as the abrasive particle adsorption parameter increases, the amount of water-soluble polymer contained in the supernatant after centrifugation of test solution L decreases, and the amount of water-soluble polymer adsorbed onto colloidal silica increases. Therefore, it is presumed that the higher the abrasive particle adsorption parameter of the water-soluble polymer, the easier it is for the water-soluble polymer to adsorb onto the abrasive particles in the actual polishing composition, and the amount of adsorption increases.

[0105] For water-soluble polymers with a grit adsorption parameter of less than 5, the grit adsorption parameter is not particularly limited, but is typically 0 or greater. Additionally, the grit adsorption parameter is not particularly limited, but is preferably 2 or less. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced.

[0106] For water-soluble polymers with an abrasive adsorption parameter of 5 or higher, the abrasive adsorption parameter is not particularly limited, but is preferably 60 or higher. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. Additionally, the abrasive adsorption parameter is not particularly limited, but is typically 100 or lower.

[0107] The water-soluble polymer used in the present invention is not particularly limited, but, for example, may be a polymer having at least one functional group selected from the group consisting of a cation, an anion, and a non-ionic group in the molecule. Specifically, examples may include a polymer having a partial structure containing a hydroxyl group, a carboxyl group or a salt thereof, an acyloxy group, a sulfon group or a salt thereof, or a nitrogen atom in the molecule (e.g., an amide group, an amidino group, an imino group, an imide group, a quaternary nitrogen structure, a heterocyclic structure containing a nitrogen atom as a ring-forming atom), a heterocyclic structure containing a heteroatom other than a nitrogen atom as a ring-forming atom, a vinyl structure, a polyoxyalkylene structure, etc.

[0108] As for water-soluble polymers having an abrasive adsorption parameter of 5 or higher, they are not particularly limited, but preferably include cellulose derivatives, polymers having a partial structure containing nitrogen atoms within the molecule, polymers containing two or more hydroxyl groups within the molecule and having an unsubstituted polyoxyalkylene structure, etc. The water-soluble polymer having an abrasive adsorption parameter of 5 or higher included in the polishing composition S1 preferably includes at least one selected from the group consisting of these compounds.

[0109] Cellulose derivatives are not particularly limited, but examples include hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, etc.

[0110] Polymers having a partial structure containing nitrogen atoms within the molecule are not particularly limited, but examples include poly(meth)acrylamide, polyalkylaminoalkyl(meth)acrylamide, polyhydroxyalkyl(meth)acrylamide, polyN-(meth)acryloylmorpholine, polyN-vinylpyrrolidone, copolymers containing polyN-vinylpyrrolidone in part of the structure, polyN-vinylimidazole, polyN-vinylcarbazole, polyN-vinylcaprolactam, copolymers containing polyN-vinylcaprolactam in part of the structure, polyN-vinylpiperidine, polyamidine, polyethyleneimine, hydrophilized polyimide, various polyamino acids, imine derivatives such as poly(N-acylalkyleneimine), etc.

[0111] Polymers having two or more hydroxyl groups within the molecule and having an unsubstituted polyoxyalkylene structure are not particularly limited, but examples include polyethylene oxide (PEO), polypropylene oxide (PPO), polybutylene oxide (PBO), block copolymers of ethylene oxide (EO) and propylene oxide (PO), and random copolymers of EO and PO.

[0112] Among these, hydroxyethylcellulose or polyN-(meth)acryloylmorpholine is preferred, and polyN-acryloylmorpholine is more preferred, from the perspective that surface defects occurring on the polished surface of the substrate are further reduced.

[0113] The weight-average molecular weight of a water-soluble polymer having an abrasive adsorption parameter of 5 or higher is not particularly limited, but is preferably 1,000 or higher, more preferably 10,000 or higher, even more preferably 100,000 or higher, and particularly preferably 200,000 or higher. The weight-average molecular weight of a water-soluble polymer having an abrasive adsorption parameter of 5 or higher can be, for example, 300,000 or higher. In addition, the weight-average molecular weight of a water-soluble polymer having an abrasive adsorption parameter of 5 or higher is not particularly limited, but is preferably 2,000,000 or lower, more preferably 1,500,000 or lower, even more preferably 1,000,000 or lower, and particularly preferably 500,000 or lower. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. The weight-average molecular weight of a water-soluble polymer having a particle adsorption parameter of 5 or higher can be measured in polyoxyethylene equivalent by gel permeation chromatography (GPC). In addition, specific measurement methods are described in the examples. Examples of weight-average molecular weights of a water-soluble polymer having a preferred particle adsorption parameter of 5 or higher include, but are not limited to, 1,000 or higher and 2,000,000 or lower, 10,000 or higher and 1,500,000 or lower, 100,000 or higher and 1,000,000 or lower, 200,000 or higher and 500,000 or lower, 300,000 or higher and 500,000 or lower.

[0114] As for water-soluble polymers with an abrasive adsorption parameter of less than 5, they are not particularly limited, but preferably include polymers having two or more hydroxyl groups in the molecule and having a substituted polyoxyalkylene structure, polymers having two or more hydroxyl groups in the molecule and having a structural unit derived from vinyl alcohol, polymers having an anionic group in the molecule, etc. The water-soluble polymer with an abrasive adsorption parameter of less than 5 included in the polishing composition S2 preferably includes at least one selected from the group consisting of these compounds.

[0115] In a polymer comprising two or more hydroxyl groups within the molecule and having a substituted polyoxyalkylene structure, a hydroxyl group is preferred as the substituent substituting the polyoxyalkylene group. The polymer comprising two or more hydroxyl groups within the molecule and having a substituted polyoxyalkylene structure is not particularly limited, but examples include polyglycerin.

[0116] In a polymer comprising two or more hydroxyl groups within the molecule and a structural unit derived from vinyl alcohol, the structural unit derived from vinyl alcohol refers to a vinyl alcohol unit (a structural portion represented by -CH2-CH(OH)-; hereinafter also referred to as a "VA unit"). Furthermore, a polymer comprising two or more hydroxyl groups within the molecule and having a structural unit derived from vinyl alcohol may be a copolymer comprising, in addition to the VA unit, a non-vinyl alcohol unit (a structural unit derived from a monomer other than vinyl alcohol, hereinafter also referred to as a "non-VA unit"). Examples of non-VA units are not particularly limited and may include structural units derived from ethylene, vinyl acetate, vinyl propionate, vinyl hexanoate, 2-butenediol, etc. A polymer comprising structural units derived from vinyl alcohol may include only one type of non-VA unit or two or more types of non-VA units when including non-VA units. In a polymer comprising structural units derived from vinyl alcohol and containing two or more hydroxyl groups within the molecule, the molar ratio of VA units to the total molar ratio of repeating units is not particularly limited, but is preferably 50% or more, more preferably 65% ​​or more, even more preferably 70% or more, and particularly preferably 75% or more (upper limit 100%). The total repeating units may substantially consist of VA units. The degree of saponification of polyvinyl alcohol is not particularly limited, but is preferably 50 mol% or more, more preferably 65 mol% or more, even more preferably 70 mol% or more, and particularly preferably 75 mol% or more (upper limit 100 mol%). Polymers containing two or more hydroxyl groups within the molecule and structural units derived from vinyl alcohol are not particularly limited, but examples include polyvinyl alcohol (PVA), acetalized polyvinyl alcohol, vinyl alcohol-ethylene copolymer, vinyl alcohol-butanediol copolymer, etc.When the polymer containing structural units derived from vinyl alcohol is acetalized polyvinyl alcohol, the type of acetalization is not particularly limited, but examples include polyvinylformal, polyvinylacetoacetal, polyvinylpropyral, polyvinyl ethyral, polyvinyl butyral, etc. The degree of acetalization is not particularly limited, but preferably 1 mol% or more and 50 mol% or less, more preferably 10 mol% or more and 45 mol% or less, and even more preferably 20 mol% or more and 40 mol% or less.

[0117] Polymers having anionic groups within the molecule are not particularly limited, but preferably include polymers having a carboxyl group or a salt thereof within the molecule, polymers having a sulfon group or a salt thereof within the molecule, etc. Specific examples include poly(meth)acrylic acid, poly(meth)acrylamide alkylsulfonic acid, polyisoprenesulfonic acid, polyvinylsulfonic acid, polyallylsulfonic acid, polyisoamilenesulfonic acid, polystyrenesulfonic acid, salts thereof, etc.

[0118] Among these, a polymer having a structural unit derived from vinyl alcohol and containing two or more hydroxyl groups within the molecule is preferred in terms of further reducing surface defects occurring on the polished surface of the substrate, polyvinyl alcohol or acetalized polyvinyl alcohol is more preferred, and acetalized polyvinyl alcohol is even more preferred.

[0119] In this regard, in a preferred embodiment of the present invention, the water-soluble polymer having a particle adsorption parameter of 5 or more is at least one polymer selected from the group consisting of a cellulose derivative, a polymer having a partial structure containing a nitrogen atom within the molecule, and a polymer having two or more hydroxyl groups within the molecule and having an unsubstituted polyoxyalkylene structure, and the water-soluble polymer having a particle adsorption parameter of less than 5 is at least one polymer selected from the group consisting of a polymer having two or more hydroxyl groups within the molecule and having a substituted polyoxyalkylene structure, a polymer having two or more hydroxyl groups within the molecule and having a structural unit derived from vinyl alcohol, and a polymer having an anionic group within the molecule.

[0120] The weight-average molecular weight of a water-soluble polymer with an abrasive adsorption parameter of less than 5 is not particularly limited as long as it is 1,000 or more, but preferably 2,000 or more, more preferably 5,000 or more, even more preferably 9,000 or more, even more preferably 10,000 or more, and particularly preferably 12,000 or more. In addition, the weight-average molecular weight of a water-soluble polymer with an abrasive adsorption parameter of less than 5 is not particularly limited, but preferably 2,000,000 or less, more preferably 1,000,000 or less, even more preferably 500,000 or less, even more preferably 100,000 or less, and particularly preferably 80,000 or less. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. In addition, the weight-average molecular weight of a water-soluble polymer with an abrasive adsorption parameter of less than 5 can be, for example, 50,000 or less. The weight-average molecular weight of a water-soluble polymer with a particle adsorption parameter of less than 5 can be measured in polyoxyethylene equivalent by gel permeation chromatography (GPC). In addition, specific measurement methods are described in the examples. Examples of a preferred range of weight-average molecular weight of a water-soluble polymer with a particle adsorption parameter of less than 5 include 2,000 or more and 2,000,000 or less, 5,000 or more and 1,000,000 or less, 9,000 or more and 500,000 or less, 9,000 or more and 100,000 or less, 9,000 or more and 80,000 or less, 9,000 or more and 50,000 or less, but are not limited thereto.

[0121] Water-soluble polymers with a particle adsorption parameter of 5 or higher and water-soluble polymers with a particle adsorption parameter of less than 5 may each be commercially available products or synthetic products. In addition, water-soluble polymers with a particle adsorption parameter of 5 or higher and water-soluble polymers with a particle adsorption parameter of less than 5 may each be used as a single type or in combination of two or more types.

[0122] The concentration of the water-soluble polymer having an abrasive adsorption parameter of 5 or higher in the polishing composition S1 is not particularly limited, but is preferably 0.0001 mass% or higher with respect to the total mass of the polishing composition S1, more preferably 0.001 mass% or higher, even more preferably 0.003 mass% or higher, and particularly preferably 0.004 mass% or higher. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. This is presumed to be because the protective effect of the abrasives in polishing step 1 is further improved. In addition, the concentration of the water-soluble polymer having an abrasive adsorption parameter of 5 or higher in the polishing composition S1 is not particularly limited, but is preferably 1 mass% or lower with respect to the total mass of the polishing composition S1, and more preferably 0.01 mass% or lower. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. This is presumed to be because the amount of water-soluble polymer having an abrasive adsorption parameter of 5 or higher remaining after polishing step 1 becomes smaller. In addition, the concentration of the water-soluble polymer having an abrasive adsorption parameter of 5 or higher in the polishing composition S1 can be, for example, 0.008 mass% or less with respect to the total mass of the polishing composition S1, and for example, 0.005 mass% or less. Examples of the range of concentrations of the water-soluble polymer having an abrasive adsorption parameter of 5 or higher in the preferred polishing composition S1 include, but are not limited to, 0.0001 mass% or more and 1 mass% or less, 0.001 mass% or more and 0.01 mass% or less, 0.003 mass% or more and 0.008 mass% or less, and 0.004 mass% or more and 0.005 mass% or less with respect to the total mass of the polishing composition S1.

[0123] When the polishing composition S1 includes a water-soluble polymer with an abrasive adsorption parameter of less than 5, the concentration of the water-soluble polymer with an abrasive adsorption parameter of less than 5 in the polishing composition S1 is not particularly limited, but is preferably 0.0001 mass% or more, more preferably 0.001 mass% or more, even more preferably 0.002 mass% or more, and particularly preferably 0.003 mass% or more with respect to the total mass of the polishing composition S1. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. This is presumed to be because, due to the presence of the water-soluble polymer with an abrasive adsorption parameter of less than 5, the abrasive particles remaining after polishing step 1 or the water-soluble polymer with an abrasive adsorption parameter of 5 or more becomes smaller. In addition, the concentration of the water-soluble polymer having an abrasive adsorption parameter of less than 5 in the polishing composition S1 is not particularly limited, but is preferably 1 mass% or less and more preferably 0.01 mass% or less with respect to the total mass of the polishing composition S1. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. It is presumed that this is because the inhibition of adsorption of abrasive particles in polishing step 1 or water-soluble polymers having an abrasive adsorption parameter of 5 or more onto the substrate by the water-soluble polymer having an abrasive adsorption parameter of less than 5 becomes less likely to occur, and thus the effect of removing defects in polishing step 1 is obtained more favorably. In addition, the concentration of the water-soluble polymer having an abrasive adsorption parameter of less than 5 in the polishing composition S1 can be, for example, 0.008 mass% or less, and for example, 0.005 mass% or less with respect to the total mass of the polishing composition S1. Examples of the concentration range of a water-soluble polymer having an abrasive particle adsorption parameter of less than 5 in a preferred polishing composition S1 include, with respect to the total mass of the polishing composition S1, 0.0001 mass% or more and 1 mass% or less, 0.001 mass% or more and 0.01 mass% or less, 0.002 mass% or more and 0.008 mass% or less, 0.Examples include 0.003 mass% or more and 0.005 mass% or less, but are not limited to these.

[0124] In this regard, the concentration of the water-soluble polymer in the polishing composition S1 (i.e., the sum of the concentration of the water-soluble polymer with an abrasive adsorption parameter of 5 or more and the concentration of the water-soluble polymer with an abrasive adsorption parameter of less than 5 in the polishing composition S1, hereinafter the same) is not particularly limited, but is preferably 0.0001 mass% or more with respect to the total mass of the polishing composition S1, more preferably 0.001 mass% or more, even more preferably 0.003 mass% or more, and particularly preferably 0.004 mass% or more. In addition, the concentration of the water-soluble polymer in the polishing composition S1 is not particularly limited, but is preferably 2 mass% or less with respect to the total mass of the polishing composition S1, more preferably 0.02 mass% or less, even more preferably 0.016 mass% or less, and particularly preferably 0.01 mass% or less. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. Examples of the concentration of the water-soluble polymer in the preferred polishing composition S1 include, but are not limited to, 0.0001 mass% or more and 2 mass% or less, 0.001 mass% or more and 0.02 mass% or less, 0.003 mass% or more and 0.016 mass% or less, and 0.004 mass% or more and 0.01 mass% or less, based on the total mass of the polishing composition S1.

[0125] The concentration of the water-soluble polymer having an abrasive particle adsorption parameter of less than 5 in the polishing composition S2 is not particularly limited, but is preferably 0.0001 mass% or more with respect to the total mass of the polishing composition S2, more preferably 0.001 mass% or more, even more preferably 0.002 mass% or more, and particularly preferably 0.003 mass% or more. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. It is presumed that this is because the cleaning effect in polishing step 2, that is, the reduction effect of abrasive particles or water-soluble polymers, is further improved. In addition, the concentration of the water-soluble polymer having an abrasive particle adsorption parameter of less than 5 in the polishing composition S2 is not particularly limited, but is preferably 1 mass% or less with respect to the total mass of the polishing composition S2, more preferably 0.01 mass% or less, and even more preferably 0.008 mass% or less. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. This reason is presumed to be because the amount of water-soluble polymer with an abrasive adsorption parameter of less than 5 remaining after polishing step 2 becomes smaller. In addition, the concentration of water-soluble polymer with an abrasive adsorption parameter of less than 5 in the polishing composition S2 can be, for example, 0.005 mass% or less with respect to the total mass of the polishing composition S2. Examples of the concentration of water-soluble polymer with an abrasive adsorption parameter of less than 5 in the preferred polishing composition S2 include, but are not limited to, 0.0001 mass% or more and 1 mass% or less, 0.001 mass% or more and 0.01 mass% or less, 0.002 mass% or more and 0.008 mass% or less, 0.003 mass% or more and 0.005 mass% or less with respect to the total mass of the polishing composition S2.

[0126] The polishing composition S2 does not contain a water-soluble polymer with an abrasive adsorption parameter of 5 or higher in an amount (concentration) of 0.005 mass% or higher. The concentration of the water-soluble polymer with an abrasive adsorption parameter of 5 or higher in the polishing composition S2 is not particularly limited as long as it is less than 0.005 mass% (less than 0.005 mass% relative to the total mass of the polishing composition S2). However, it is preferable that the polishing composition S2 does not substantially contain a water-soluble polymer with an abrasive adsorption parameter of 5 or higher, and it is most preferable that it does not contain a water-soluble polymer with an abrasive adsorption parameter of 5 or higher. Furthermore, in this specification, the phrase “the polishing composition S2 does not substantially contain a water-soluble polymer with an abrasive adsorption parameter of 5 or higher” indicates that the concentration of the water-soluble polymer with an abrasive adsorption parameter of 5 or higher is less than 0.0001 mass% relative to the total mass of the polishing composition S2. In this case, surface defects occurring on the polished surface of the substrate are further reduced. It is presumed that this is because the amount of water-soluble polymer with an abrasive adsorption parameter of 5 or more remaining after polishing step 2 is reduced, and furthermore, the effect of removing abrasive particles or water-soluble polymers in polishing step 2 is less likely to be inhibited, and thus the effect of reducing abrasive particles or water-soluble polymers in polishing step 2 is further improved. Examples of the concentration of water-soluble polymers with an abrasive adsorption parameter of 5 or more in a preferred polishing composition S2 include less than 0.0001 mass% with respect to the total mass of the polishing composition S2, or not containing water-soluble polymers with an abrasive adsorption parameter of 5 or more, but are not limited to these.

[0127] In this regard, the concentration of the water-soluble polymer in the polishing composition S2 (i.e., the sum of the concentration of the water-soluble polymer with an abrasive adsorption parameter of 5 or more and the concentration of the water-soluble polymer with an abrasive adsorption parameter of less than 5 in the polishing composition S2, hereinafter the same) is not particularly limited, but is preferably 0.0001 mass% or more with respect to the total mass of the polishing composition S2, more preferably 0.001 mass% or more, even more preferably 0.002 mass% or more, and particularly preferably 0.003 mass% or more. In addition, the concentration of the water-soluble polymer in the polishing composition S2 is not particularly limited, but is preferably 1 mass% or less with respect to the total mass of the polishing composition S2, more preferably 0.01 mass% or less, even more preferably 0.008 mass% or less, and particularly preferably 0.005 mass% or less. In these cases, surface defects occurring on the polished surface of the substrate are further reduced. Examples of the concentration of the water-soluble polymer in the preferred polishing composition S2 include, but are not limited to, 0.0001 mass% or more and 1 mass% or less, 0.001 mass% or more and 0.01 mass% or less, 0.002 mass% or more and 0.008 mass% or less, and 0.003 mass% or more and 0.005 mass% or less, based on the total mass of the polishing composition S2.

[0128] Accordingly, in a preferred embodiment of the present invention, the concentration of the water-soluble polymer in the polishing composition S1 is 0.0001 mass% or more and 2 mass% or less with respect to the total mass of the polishing composition S1, and the concentration of the water-soluble polymer in the polishing composition S2 is 0.0001 mass% or more and 1 mass% or less with respect to the total mass of the polishing composition S2.

[0129] The relationship between the concentration of the water-soluble polymer in polishing composition S2 and the concentration of the water-soluble polymer in polishing composition S1 is not particularly limited, but it is preferable that the concentration of the water-soluble polymer in polishing composition S2 be less than or equal to the concentration of the water-soluble polymer in polishing composition S1. In addition, the ratio of the concentration of the water-soluble polymer in polishing composition S2 to the concentration of the water-soluble polymer in polishing composition S1 (concentration of the water-soluble polymer in polishing composition S2 / concentration of the water-soluble polymer in polishing composition S1) is not particularly limited, but is preferably 0.1 or more and 1 or less, and more preferably 0.2 or more and 0.95 or less. In these cases, surface defects occurring on the polished surface of the substrate can be further reduced. In addition, the above ratio can be, for example, 0.3 or more and 0.6 or less, and for example, 0.4 or more and 0.5 or less.

[0130] (Basic compound)

[0131] Polishing composition S1 and polishing composition S2 may each independently further contain a basic compound. Furthermore, it is more preferable that polishing composition S1 and polishing composition S2 further contain a basic compound. Depending on the type of substrate, the basic compound may chemically act upon the polishing surface of the substrate to chemically polish the substrate.

[0132] Basic compounds are not particularly limited, but examples include hydroxides of alkali metals or alkaline earth metals or their salts, quaternary ammonium, ammonia, quaternary ammonium hydroxide or its salts, amines, etc.

[0133] Specific examples of alkali metals are not particularly limited, but include potassium, sodium, etc. Alkaline earth metals are not particularly limited, but include calcium, etc. Salts of alkali metals or alkaline earth metals are not particularly limited, but examples include their carbonates, bicarbonates, sulfates, acetates, etc. Specific examples of hydroxides of alkali metals or alkaline earth metals or their salts are not particularly limited, but examples include calcium hydroxide, potassium hydroxide, potassium carbonate, potassium bicarbonate, potassium sulfate, potassium acetate, potassium chloride, sodium hydroxide, sodium bicarbonate, sodium carbonate, calcium hydroxide, etc.

[0134] Specific examples of quaternary ammonium include, but are not particularly limited, tetramethylammonium, tetraethylammonium, tetrabutylammonium, etc.

[0135] Specific examples of quaternary ammonium hydroxide or its salts are not particularly limited, but include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, etc.

[0136] Specific examples of amines include compounds having a structure represented by the following chemical formula (I), triethylenetetramine, piperazine anhydrous, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, azoles such as imidazole or triazole, etc.

[0137]

[0138] In the above chemical formula (I), R 1 to R 3 Each is independently a hydrogen atom, a substituted or unsubstituted alkyl group.

[0139] However, R 1 to R 3 Exclude cases where all of them are hydrogen atoms.

[0140] R 1 to R 3In the case where each of the is a substituted alkyl group, the substituent included in the substituted alkyl group is not particularly limited, but a hydroxyl group, a substituted or unsubstituted amino group is preferred, and a hydroxyl group, an unsubstituted amino group is more preferred.

[0141] R 1 to R 3 In the case where each of the is a substituted or unsubstituted alkyl group, the number of carbon atoms of the alkyl group (in the case of a substituted alkyl group, the alkyl group in an unsubstituted state) is not particularly limited, but is preferably 1 or more and 6 or less, more preferably 2 or more and 3 or less, and particularly preferably 2.

[0142] Preferred specific examples of amines include, but are not limited to, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, piperazine anhydrous, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, and azoles such as imidazole or triazole. The amine included in polishing composition S1 and polishing composition S2 preferably comprises at least one compound selected from the group consisting of these compounds.

[0143] Among these, quaternary ammonium, ammonia, quaternary ammonium hydroxide or its salt, and amine are preferred. As for the basic compound included in the polishing composition S1, quaternary ammonium, ammonia, quaternary ammonium hydroxide or its salt is more preferred, and ammo is even more preferred. The basic compound included in the polishing composition S1 preferably comprises at least one compound selected from the group consisting of these compounds. As for the basic compound included in the polishing composition S2, ammonia and a compound having a structure represented by the above chemical formula (1) are more preferred, and ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, and diethylenetriamine are more preferred, and ammonia, trimethylamine, ethylamine, diethylamine, triethylamine, and triethanolamine are more preferred, and trimethylamine, ethylamine, diethylamine, triethylamine, and triethanolamine are more preferred, and trimethylamine, ethylamine, and triethylamine are more preferred, and ethylamine and triethylamine are more preferred, and triethylamine is particularly preferred. The basic compound included in the polishing composition S2 preferably comprises at least one compound selected from the group consisting of these compounds.

[0144] Basic compounds may be commercially available or synthetic. Additionally, basic compounds may be used individually or in combination of two or more types.

[0145] The concentration of the basic compound in the polishing composition S1 is not particularly limited, but is preferably 0.0001 mass% or more with respect to the total mass of the polishing composition S1, more preferably 0.001 mass% or more, even more preferably 0.003 mass% or more, and particularly preferably 0.004 mass% or more. Within these ranges, the polishing speed is further improved. The concentration of the basic compound in the polishing composition S1 is not particularly limited, but is preferably 1 mass% or less with respect to the total mass of the polishing composition S1, more preferably 0.01 mass% or less, and even more preferably 0.008 mass% or less. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. Examples of the concentration of the basic compound in the preferred polishing composition S1 include, but are not limited to, 0.0001 mass% or more and 1 mass% or less, 0.001 mass% or more and 0.01 mass% or less, 0.003 mass% or more and 0.008 mass% or less, and 0.004 mass% or more and 0.008 mass% or less, based on the total mass of the polishing composition S1.

[0146] The concentration of the basic compound in the polishing composition S2 is not particularly limited, but is preferably 0.0001 mass% or more with respect to the total mass of the polishing composition S2, more preferably 0.0004 mass% or more, even more preferably 0.0008 mass% or more, even more preferably 0.001 mass% or more, particularly preferably 0.003 mass% or more, and also particularly preferably 0.004 mass% or more. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. The concentration of the basic compound in the polishing composition S2 is not particularly limited, but is preferably 1 mass% or less with respect to the total mass of the polishing composition S2, more preferably 0.1 mass% or less, even more preferably 0.01 mass% or less, even more preferably 0.008 mass% or less, particularly preferably 0.005 mass% or less, and also particularly preferably 0.003 mass% or less. If these ranges are within, surface defects occurring on the polished surface of the substrate are further reduced. Examples of the concentration of the basic compound in the preferred polishing composition S1 include, but are not limited to, 0.0001 mass% or more and 1 mass% or less, 0.0004 mass% or more and 0.1 mass% or less, 0.0008 mass% or more and 0.01 mass% or less, 0.0008 mass% or more and 0.008 mass% or less, 0.0008 mass% or more and 0.005 mass% or less, and 0.0008 mass% or more and 0.003 mass% or less, based on the total mass of the polishing composition S1.

[0147] (Surfactant)

[0148] Polishing composition S1 and polishing composition S2 may each independently further contain a surfactant. Additionally, it is preferable that polishing composition S1 and polishing composition S2 further contain a surfactant. The surfactant acts to suppress roughness of the polished surface of the substrate and reduce surface defects. In particular, when a basic compound is included in the polishing composition, there is a tendency for roughness to occur on the polished surface of the substrate due to chemical polishing by the basic compound. For this reason, the combined use of a basic compound and a surfactant is particularly effective.

[0149] Surfactants are not particularly limited, but examples include nonionic surfactants, cationic surfactants, and anionic surfactants. Among these, nonionic surfactants are preferred from the perspective of further reducing surface defects occurring on the polished surface of the substrate.

[0150] As nonionic surfactants, examples include homopolymers of oxyalkylene, multiple types of oxyalkylene copolymers, polyoxyalkylene adducts, etc., although not particularly limited. In addition, specific examples of polyoxyalkylene adducts include polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene alkylamines, polyoxyalkylene fatty acid esters, polyoxyalkylene glyceryl ether fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, etc.

[0151] Specific examples of nonionic surfactants are not particularly limited, but include polyoxyethylene propyl ether, polyoxyethylene butyl ether, polyoxyethylene pentyl ether, polyoxyethylene hexyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene isodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene isostearyl ether, polyoxyethylene oleyl ether, polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene styrene phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearylamide, polyoxyethylene oleylamide, polyoxyethylene monolauric acid ester, Examples include polyoxyethylene monostearic acid esters, polyoxyethylene distearic acid esters, polyoxyethylene monooleic acid esters, polyoxyethylene dioleic acid esters, monolauric acid polyoxyethylene sorbitan, monopaltimate polyoxyethylene sorbitan, monostearic acid polyoxyethylene sorbitan, monooleic acid polyoxyethylene sorbitan, trioleic acid polyoxyethylene sorbitan, tetraoleic acid polyoxyethylene sorbitan, polyoxyethylene castor oil, polyoxyethylene hardened castor oil, etc.

[0152] Among these, polyoxyalkylene adducts are preferred in terms of further reducing surface defects occurring on the polished surface of the substrate, polyoxyalkylene alkyl ethers are more preferred, polyoxyethylene alkyl ethers are even more preferred, and polyoxyethylene decyl ethers are particularly preferred.

[0153] The molecular weight of the surfactant is not particularly limited, but preferably is less than 1,000, more preferably less than 500, and even more preferably less than 400. It is preferable to use the molecular weight of the surfactant calculated from the chemical formula.

[0154] Commercial surfactants may be used, or synthetic surfactants may be used. Additionally, one type of surfactant may be used alone, or two or more types may be used in combination.

[0155] It is preferable that the surfactant included in the polishing composition S1 and the polishing composition S2 each include a nonionic surfactant. In addition, it is preferable that the nonionic surfactant included in the polishing composition S1 and the polishing composition S2 each include at least one selected from the group consisting of the compounds listed above.

[0156] The concentration of the surfactant in the polishing composition S1 is not particularly limited, but is preferably 0.0001 mass% or more with respect to the total mass of the polishing composition S1, more preferably 0.0002 mass% or more, and even more preferably 0.0004 mass% or more. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. In addition, the concentration of the surfactant in the polishing composition S1 can be, for example, 0.0006 mass% or more with respect to the total mass of the polishing composition S1. In addition, the concentration of the surfactant in the polishing composition S1 is not particularly limited, but is preferably 1 mass% or less with respect to the total mass of the polishing composition S1, more preferably 0.01 mass% or less, even more preferably 0.001 mass% or less, and particularly preferably 0.0008 mass% or less. Within these ranges, the polishing speed is further improved. Examples of the concentration of a surfactant in a preferred polishing composition S1 include, but are not limited to, 0.0001 mass% or more and 1 mass% or less, 0.0002 mass% or more and 0.01 mass% or less, 0.0004 mass% or more and 0.001 mass% or less, and 0.0004 mass% or more and 0.0008 mass% or less, based on the total mass of the polishing composition S1.

[0157] The concentration of the surfactant in the polishing composition S2 is not particularly limited, but is preferably 0.0001 mass% or more with respect to the total mass of the polishing composition S2, more preferably 0.0002 mass% or more, and even more preferably 0.0004 mass% or more. Within these ranges, surface defects occurring on the polished surface of the substrate are further reduced. In addition, the concentration of the surfactant in the polishing composition S2 can be, for example, 0.0006 mass% or more with respect to the total mass of the polishing composition S2. In addition, the concentration of the surfactant in the polishing composition S2 is not particularly limited, but is preferably 1 mass% or less with respect to the total mass of the polishing composition S2, more preferably 0.01 mass% or less, even more preferably 0.001 mass% or less, and particularly preferably 0.0008 mass% or less. Within these ranges, the polishing speed is further improved. Examples of the concentration of a surfactant in a preferred polishing composition S2 include, but are not limited to, 0.0001 mass% or more and 1 mass% or less, 0.0002 mass% or more and 0.01 mass% or less, 0.0004 mass% or more and 0.001 mass% or less, and 0.0006 mass% or more and 0.0008 mass% or less, based on the total mass of the polishing composition S2.

[0158] (Dispersed)

[0159] Polishing composition S1 and polishing composition S2 contain water as a dispersion medium. The dispersion medium acts to disperse or dissolve each component.

[0160] The water content in the dispersion medium is not particularly limited, but it is preferable that it be 50 mass% or more relative to the total mass of the dispersion medium, more preferable that it be 90 mass% or more, and even more preferable that it be water only. As for the water, water that contains as few impurities as possible is preferred from the perspective of preventing contamination of the object to be polished or interference with the action of other components. For example, water with a total content of transition metal ions of 100 mass ppb or less is preferred. Here, the purity of the water can be increased by operations such as the removal of impurity ions using an ion exchange resin, the removal of foreign matter by a filter, or distillation. Specifically, as for the water, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, etc.

[0161] Polishing composition S1 and polishing composition S2 may each contain an organic solvent in addition to water as a dispersion medium, provided that the dispersibility or solubility of each component can be improved. As for the organic solvent, any known organic solvent may be used without particular limitation. Additionally, one type of organic solvent may be used alone, or two or more types may be used in combination.

[0162] (Other ingredients)

[0163] Polishing composition S1 and polishing composition S2 may each independently contain additional components other than those exemplified above, provided that such inclusion does not impede the effects of the present invention. Other components may include known components that can be used in polishing compositions or rinse polishing compositions, without being particularly limited. Specific examples may include, but are not limited to, acids, chelating agents, preservatives, antifungal agents, dissolved gases, reducing agents, etc.

[0164] (Method for manufacturing a polishing composition)

[0165] The method for manufacturing the polishing composition S1 is not particularly limited if it comprises mixing abrasive particles 1, a water-soluble polymer having an abrasive particle adsorption parameter of 5 or more, water, and other components added as necessary. Additionally, the method for manufacturing the polishing composition S2 is not particularly limited if it comprises mixing abrasive particles 2, a water-soluble polymer having an abrasive particle adsorption parameter of less than 5, water, and other components added as necessary.

[0166] The mixing method when mixing each component is not particularly limited, and known methods may be appropriately used. In addition, the mixing temperature is not particularly limited, but is generally preferred to be between 10°C and 40°C, and may be heated to increase the dissolution rate. In addition, the mixing time is not particularly limited.

[0167] [Object to be polished]

[0168] In a polishing method related to one embodiment of the present invention, the substrate to be polished is not particularly limited, but is preferably a semiconductor substrate. From this, another aspect of the present invention may be described as a method for manufacturing a semiconductor substrate comprising polishing a substrate using the polishing method. Examples of substrates include a substrate composed of a single layer, or a substrate comprising a layer to be polished and another layer (e.g., a support layer or another functional layer).

[0169] In a polishing method related to one embodiment of the present invention, the substrate to be polished is not particularly limited, but preferably comprises a material having silicon-silicon bonds. Examples of materials having silicon-silicon bonds include polysilicon, amorphous silicon, single-crystal silicon, n-type doped single-crystal silicon, p-type doped single-crystal silicon, Si-based alloys such as SiGe, etc. Among these, from the viewpoint that the effects of the present invention can be obtained more significantly, it is preferable to use single-crystal silicon, n-type doped single-crystal silicon, or p-type doped single-crystal silicon, and more preferable to use p-type doped single-crystal silicon. These materials having silicon-silicon bonds may be used alone or in combination of two or more types.

[0170] In this regard, it is preferable that the substrate be a silicon substrate (silicon wafer).

[0171] Abrasive Composition Set

[0172] Another aspect of the present invention is,

[0173] It is a set of polishing compositions used in a method for polishing a substrate, and

[0174] The above polishing method includes a polishing process, and

[0175] The polishing process comprises two or more polishing stages that polish the substrate by rotating the polishing plate while supplying a polishing composition to the contact surface of the substrate and a polishing pad installed on the polishing plate.

[0176] The above two or more grinding stages are,

[0177] Grinding plate 1, which is ground on a grinding plate, and

[0178] After the above grinding step 1, it includes a grinding step 2 that is ground on the same grinding plate as the above grinding step 1, and

[0179] The above set of polishing compositions is,

[0180] A polishing composition S1 used in the polishing step 1, comprising abrasive particles 1, water, and a water-soluble polymer having an abrasive particle adsorption parameter of 5 or more calculated by the steps of (1) to (4) below, and

[0181] A polishing composition S2 used in the polishing step 2, comprising abrasive particles 2, water, and a water-soluble polymer having an abrasive particle adsorption parameter of less than 5, and further comprising not containing a water-soluble polymer having an abrasive particle adsorption parameter of 5 or more in an amount of 0.005 mass% or more (i.e., the concentration of the water-soluble polymer having an abrasive particle adsorption parameter of 5 or more in the polishing composition S2 is less than 0.005 mass% with respect to the total mass of the polishing composition S2).

[0182] This relates to a set of abrasive compositions comprising:

[0183] (1) Prepare a test solution L containing 0.08 mass% of colloidal silica with an average primary particle size of 25 nm and an average secondary particle size of 50 nm, 0.004 mass% of a water-soluble polymer to be measured and 0.005 mass% of ammonia, with the remainder being water.

[0184] (2) Measure the total organic carbon concentration (TOC value) of the above test solution L, and set the obtained TOC value as the total organic carbon concentration W0 [mass ppm] of the water-soluble polymer of the subject to measurement contained in the above test solution L, and

[0185] (3) The above test solution L is centrifuged at 26,000 rpm for 30 minutes to separate it into a precipitate and a supernatant, and the TOC value of the supernatant is measured, and the obtained TOC value is set as the total organic carbon concentration W1 [mass ppm] of the water-soluble polymer of the subject to measurement contained in the supernatant.

[0186] (4) Calculate the adsorption ratio of the water-soluble polymer of the measurement target using the following formula, and use this value as the particle adsorption parameter.

[0187]

[0188] According to the present embodiment, it is possible to provide a means for reducing surface defects of a substrate after polishing.

[0189] In addition, the details of the polishing method are as described above. The details of the polishing process, other processes, polishing composition S1 and polishing composition S2, and the object to be polished are also as described above.

[0190] It is preferable that the polishing composition S1 is a finishing polishing composition and the polishing composition S2 is a rinse polishing composition.

[0191] The set of polishing compositions may additionally include one or more other polishing compositions as needed, in addition to polishing compositions S1 and S2. In this case, it is preferable that polishing composition S1 is a finishing polishing composition, polishing composition S2 is a rinse polishing composition, and the other polishing composition is a pre-polishing composition or a finishing polishing composition. Furthermore, it is more preferable that polishing composition S1 is a finishing polishing composition, polishing composition S2 is a rinse polishing composition, and the other polishing composition is a pre-polishing composition.

[0192] In addition, each polishing composition included in the polishing composition set may be in a concentrated form. A concentrated form refers to a concentrated liquid form of the polishing composition, and can also be understood as a raw liquid of the polishing composition. The concentration ratio is not particularly limited and, for example, can be 2 times or more and 100 times or less in terms of volume; typically, it is 5 times or more and 50 times or less, for example, 10 times or more and 40 times or less. Such a concentrated liquid can be used in a manner where it is diluted at a desired timing to prepare a polishing composition and supplied to a workpiece. Dilution can be performed, for example, by adding water to the concentrated liquid and mixing.

[0193] Examples

[0194] The present invention will be explained in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Also, unless otherwise noted, “%” and “parts” mean “mass%” and “mass parts,” respectively.

[0195] Abrasive composition

[0196] [Preparation of abrasive composition]

[0197] A polishing composition was prepared by mixing the following materials in deionized water (DIW) so as to have the compositions shown in Tables 2 to 5 below.

[0198] ·Geography

[0199] Silica A: Colloidal silica, average primary particle size by BET method 35 nm, average secondary particle size by dynamic light scattering method 70 nm,

[0200] Silica B: Colloidal silica, average primary particle size by BET method 25 nm, average secondary particle size by dynamic light scattering method 50 nm,

[0201] Silica C: Colloidal silica, average primary particle size by BET method 15 nm, average secondary particle size by dynamic light scattering method 35 nm.

[0202] · Water-soluble polymer

[0203] PVA: Polyvinyl alcohol (weight average molecular weight: 70,000, degree of saponification 98 mol% or more),

[0204] Ac-PVA: Acetalized polyvinyl alcohol (weight average molecular weight: 13,000, type of acetalization: polyvinyl ethial, degree of acetalization: 30 mol%),

[0205] Ac-PVA(2): Acetalized polyvinyl alcohol (weight average molecular weight: 9,700, type of acetalization: polyvinyl ethial, degree of acetalization: 24 mol%),

[0206] HEC: Hydroxyethylcellulose (weight average molecular weight: 250,000),

[0207] PACMO: Poly-N-Acryloylmorpholine (Weight average molecular weight: 350,000).

[0208] · Basic compounds

[0209] NH3: Water ammonia (concentration 29 mass%, values ​​listed in Tables 2 and 4 below are converted to ammonia amount),

[0210] triethylamine,

[0211] Trimethylamine,

[0212] Diethylamine,

[0213] Ethylamine,

[0214] Triethanolamine.

[0215] · Surfactants

[0216] C10EO5: Polyoxyethylene decyl ether (C 10 H 21 O(CH2CH2O)5H, molecular weight: 378).

[0217] [Weight Average Molecular Weight]

[0218] The weight-average molecular weight of the water-soluble polymer was measured using the GPC method under the following conditions.

[0219] ≪Weight-Average Molecular Weight Measurement Conditions≫

[0220] Evaluation device: HLC-8320GPC (Tosho Kabushiki Kaisha)

[0221] Sample concentration: 0.1 mass%

[0222] Column: TSKgel GMPWXL

[0223] Detector: Parallax Refractometer

[0224] Eluent: 100mM aqueous sodium nitrate solution

[0225] Flow rate: 1 mL / min

[0226] Measured temperature: 40℃

[0227] Sample injection volume: 200μL

[0228] (Polyoxyethylene equivalent).

[0229] [Grout Adsorption Parameters]

[0230] The adsorption parameters of the water-soluble polymer particles were calculated by the following steps (1) to (4).

[0231] ≪Adsorption Parameter Evaluation Conditions≫

[0232] (1) A test solution L was prepared containing 0.08 mass% of colloidal silica (PL-2 manufactured by Fuso Chemical Co., Ltd., average primary particle size 25 nm, average secondary particle size 50 nm), 0.004 mass% of a water-soluble polymer to be measured, and 0.005 mass% of ammonia, with the remainder being water.

[0233] (2) The total organic carbon concentration (TOC value) of test solution L was measured, and the obtained TOC value was defined as the total organic carbon concentration W0 [mass ppm] of the water-soluble polymer of the subject to measurement contained in test solution L.

[0234] (3) Centrifugation treatment was performed on test solution L at 26,000 rpm for 30 minutes using Avanti HP-30I manufactured by Beckmann & Coulter Co., Ltd. to separate the precipitate and the supernatant, and the TOC value of the supernatant was measured. The obtained TOC value was defined as the total organic carbon concentration W1 [mass ppm] of the water-soluble polymer of the subject to measurement contained in the supernatant.

[0235] (4) The adsorption ratio of the water-soluble polymer of the measurement target was calculated using the following formula, and this value was used as the adsorption parameter of the abrasive particles.

[0236]

[0237] Here, the total organic carbon concentration W0 [mass ppm] of the water-soluble polymer of the subject to measurement contained in test solution L and the total organic carbon concentration W1 [mass ppm] of the water-soluble polymer of the subject to measurement contained in the supernatant after centrifugation treatment of test solution L were evaluated using the total organic carbon-based TOC-L manufactured by Shimadzu Seisakusho Co., Ltd.

[0238] The values ​​of the abrasive adsorption parameters are shown in Tables 2 to 5 below. In addition, in Tables 2 to 5 below, water-soluble polymers with an abrasive adsorption parameter of less than 5 are designated as "water-soluble polymer X," and water-soluble polymers with an abrasive adsorption parameter of 5 or more are designated as "water-soluble polymer Y."

[0239] <Polishing Method>

[0240] A silicon wafer was polished by a polishing method including a polishing process comprising each polishing step listed in Table 1 below. The polishing conditions for each polishing step of the polishing method related to the examples and comparative examples are shown below.

[0241] In addition, for each polishing method related to the examples and comparative examples, the polishing composition obtained above was used as the finishing polishing composition used in the finishing polishing stage and the rinsing polishing composition used in the rinsing polishing stage, respectively. The compositions of the polishing compositions are shown in Tables 2 to 5 below.

[0242] [Jeonyeonmadang]

[0243] Single-crystal silicon wafer (Diameter: 300 mm, p-type, crystal orientation) <100> , COP free) was polished on one side under the polishing conditions shown below on a polishing plate 1 of the following polishing device using the following full polishing composition.

[0244] ≪Composition for Pre-polishing≫

[0245] A polishing composition was obtained by mixing 0.6 mass% of colloidal silica (abrasive particles, average primary particle size by BET method 35 nm, average secondary particle size by dynamic light scattering method) with respect to the total mass of the polishing composition with respect to deionized water (DIW) as a dispersion medium, 0.08 mass% of TMAH (tetramethylammonium hydroxide), and 0.0002 mass% of HEC (hydroxyethylcellulose, weight average molecular weight 1.2 million) with respect to the total mass of the polishing composition.

[0246] ≪Grinding Conditions in the Full Grinding Stage≫

[0247] Grinding device: Single-wafer grinder manufactured by Okamoto Kosaku Kikai Seisakusho, Kabushiki Kaisha, model "PNX 332B"

[0248] Grinding load: 20kPa

[0249] Plate rotation speed: 20 rpm

[0250] Template rotation speed: 20rpm

[0251] Polishing Pad: Manufactured by Fujibo Ehime Co., Ltd. Product Name "FP55"

[0252] Supply rate of abrasive composition: 1L / min

[0253] Temperature of the abrasive composition: 20℃

[0254] Surface plate cooling water temperature: 20℃.

[0255] [Finishing polishing section (polishing section 1 related to the present invention)]

[0256] Next, the single-crystal silicon wafer polished by the above-mentioned pre-polishing unit was polished on one side under the polishing conditions shown below, using the finishing polishing compositions described in Tables 2 and 3 below, by the same polishing device as the above-mentioned pre-polishing unit, on a polishing plate 2 different from the polishing plate 1.

[0257] ≪Grinding Conditions in the Finishing Grinding Stage≫

[0258] Grinding device: Single-wafer grinder manufactured by Okamoto Kosaku Kikai Seisakusho, Kabushiki Kaisha, model "PNX 332B"

[0259] Grinding load: 20kPa

[0260] Plate rotation speed: 52 rpm

[0261] Template rotation speed: 50rpm

[0262] Polishing Pad: Manufactured by Fujibo Ehime Co., Ltd. Product Name "POLYPAS (Registered Trademark) 275NX"

[0263] Polishing fluid supply rate: 1.5L / min

[0264] Polishing solution temperature: 20℃

[0265] Surface plate cooling water temperature: 20℃.

[0266] [Rinse polishing unit (polishing unit 2 related to the present invention)]

[0267] Then, the single-crystal silicon wafer polished by the finishing polishing stage was polished on one side using the rinse polishing composition described in Tables 4 and 5 below, by the same polishing device as the finishing polishing stage and the finishing polishing stage, on a polishing plate 2 identical to the finishing polishing stage, under polishing conditions identical to those in the finishing polishing stage.

[0268] [sejung]

[0269] A first cleaning tank containing a cleaning solution of NH4OH (29 mass%):H2O2 (31 mass%):deionized water (DIW) = 2:5.3:48 (volume ratio) maintained at 70°C, and a second cleaning tank containing ultrapure water at 25°C were prepared. Then, the single-crystal silicon wafer polished by the rinse polishing unit was immersed in the first cleaning tank for 6 minutes, then immersed in the second cleaning tank for 15 minutes with the ultrasonic transmitter activated, immersed again in the first cleaning tank for 6 minutes, then immersed in the second cleaning tank for 16 minutes with the ultrasonic transmitter activated, and then dried. By this, a silicon wafer after polishing was obtained.

[0270]

[0271]

[0272]

[0273]

[0274]

[0275] <Evaluation>

[0276] [Number of defects in silicon wafer after polishing]

[0277] The number of defects (pieces) of the silicon wafer after polishing obtained above was first evaluated using the optical inspection device (wafer inspection device) "SURFSCAN SP5" manufactured by KLA-TENCOR Co., Ltd., in the measurement mode: DC mode. The results are shown in Table 6 below as a ratio (%) to the number of defects of Comparative Example 2, where the number of defects (pieces) of Comparative Example 2 is set to 100%.

[0278]

[0279] From the results of Tables 1 to 6 above, it was confirmed that the substrate polished by the polishing method of Examples 1 to 10 related to the present invention has a significantly lower number of defects. On the other hand, it was confirmed that the substrate polished by the polishing method of Comparative Examples 1 to 4, which is outside the scope of the present invention, has a significantly higher number of defects compared to the substrate polished by the polishing method of Examples 1 to 10 related to the present invention.

[0280] This application is based on Japanese Patent Application No. 2021-052791 filed on March 26, 2021, the disclosure of which is incorporated by reference in its entirety.

Claims

Claim 1 A method for polishing a substrate, wherein the polishing method comprises a polishing process, wherein the polishing process comprises two or more polishing stages that polish the substrate by rotating the polishing plate while supplying a polishing composition to the contact surface between the substrate and a polishing pad installed on the polishing plate, wherein the two or more polishing stages comprise a polishing stage 1 that polishes using a polishing composition S1 on the polishing plate, and a polishing stage 2 that polishes using a polishing composition S2 on the same polishing plate as the polishing stage 1 after the polishing stage 1, wherein the polishing composition S1 contains abrasive 1, water, and a water-soluble polymer having an abrasive adsorption parameter of 5 or more calculated by the steps of (1) to (4) below, and the polishing composition S2 contains abrasive 2, water, and a water-soluble polymer having an abrasive adsorption parameter of less than 5, and furthermore, does not contain the water-soluble polymer having an abrasive adsorption parameter of 5 or more in an amount of 0.005 mass% or more. Method: (1) Prepare a test solution L containing 0.08 mass% of colloidal silica with an average primary particle size of 25 nm and an average secondary particle size of 50 nm, 0.004 mass% of a water-soluble polymer to be measured and 0.005 mass% of ammonia, with the remainder being water; (2) Measure the total organic carbon concentration (TOC value) of the test solution L and set the obtained TOC value as the total organic carbon concentration W0 of the water-soluble polymer to be measured included in the test solution L; (3) Perform centrifugation treatment at 26,000 rpm on the test solution L for 30 minutes to separate the precipitate and the supernatant, then measure the TOC value of the supernatant and set the obtained TOC value as the total organic carbon concentration W1 of the water-soluble polymer to be measured included in the supernatant; (4) Calculate the adsorption ratio of the water-soluble polymer to be measured by the following formula and use this value as the abrasive particle adsorption parameter. Claim 2 A polishing method according to claim 1, wherein the concentration of abrasive grain 1 in the polishing composition S1 is 0.001 mass% or more and 3 mass% or less with respect to the total mass of the polishing composition S1, and the concentration of abrasive grain 2 in the polishing composition S2 is 0.001 mass% or more and 3 mass% or less with respect to the total mass of the polishing composition S2. Claim 3 A polishing method according to claim 1 or 2, wherein the concentration of the abrasive grain 2 in the polishing composition S2 is less than or equal to the concentration of the abrasive grain 1 in the polishing composition S1. Claim 4 A polishing method according to claim 1 or 2, wherein the average primary particle size of the abrasive 2 is less than or equal to the average primary particle size of the abrasive 1. Claim 5 A polishing method according to claim 1 or 2, wherein the abrasive grain 1 and the abrasive grain 2 are silica. Claim 6 A polishing method according to claim 1 or 2, wherein the concentration of the water-soluble polymer in the polishing composition S1 is 0.0001 mass% or more and 2 mass% or less with respect to the total mass of the polishing composition S1, and the concentration of the water-soluble polymer in the polishing composition S2 is 0.0001 mass% or more and 1 mass% or less with respect to the total mass of the polishing composition S2. Claim 7 A polishing method according to claim 1 or 2, wherein the concentration of the water-soluble polymer in the polishing composition S2 is less than or equal to the concentration of the water-soluble polymer in the polishing composition S1. Claim 8 A polishing method according to claim 1 or 2, wherein the water-soluble polymer having an abrasive adsorption parameter of 5 or more is at least one polymer selected from the group consisting of a cellulose derivative, a polymer having a partial structure containing a nitrogen atom within the molecule, and a polymer having two or more hydroxyl groups within the molecule and having an unsubstituted polyoxyalkylene structure, and the water-soluble polymer having an abrasive adsorption parameter of less than 5 is at least one polymer selected from the group consisting of a polymer having two or more hydroxyl groups within the molecule and having a substituted polyoxyalkylene structure, a polymer having two or more hydroxyl groups within the molecule and having a structural unit derived from vinyl alcohol, and a polymer having an anionic group within the molecule. Claim 9 A polishing method according to claim 1 or 2, wherein the polishing composition S1 and the polishing composition S2 further comprise a basic compound. Claim 10 A polishing method according to claim 1 or 2, wherein the polishing composition S1 and the polishing composition S2 further comprise a surfactant. Claim 11 A polishing method according to claim 1 or 2, wherein the polishing time in the polishing step 2 is shorter than the polishing time in the polishing step 1. Claim 12 A polishing method according to claim 1 or 2, wherein the substrate is a silicon wafer. Claim 13 A method for manufacturing a semiconductor substrate, comprising polishing the substrate using the polishing method described in claim 1 or 2. Claim 14 A set of polishing compositions used in a method for polishing a substrate, wherein the polishing method comprises a polishing process, and the polishing process comprises two or more polishing stages, wherein the substrate is polished by rotating the polishing plate while supplying a polishing composition to the contact surface between the substrate and a polishing pad installed on the polishing plate, and wherein the two or more polishing stages comprise a polishing stage 1 that polishes on a polishing plate and a polishing stage 2 that polishes on the same polishing plate as the polishing stage 1 after the polishing stage 1, and wherein the set of polishing compositions comprises a polishing composition S1 used in the polishing stage 1, comprising abrasive 1, water, and a water-soluble polymer having an abrasive adsorption parameter of 5 or more calculated by the steps of (1) to (4) below, and a polishing composition used in the polishing stage 2, comprising abrasive 2, water, and a water-soluble polymer having an abrasive adsorption parameter of less than 5, and further comprising not containing the water-soluble polymer having an abrasive adsorption parameter of 5 or more in an amount of 0.005 mass% or more. A set of polishing compositions including S2: (1) prepare a test solution L containing 0.08 mass% of colloidal silica having an average primary particle size of 25 nm and an average secondary particle size of 50 nm, 0.004 mass% of a water-soluble polymer to be measured, and 0.005 mass% of ammonia, with the remainder being water; (2) measure the total organic carbon concentration (TOC value) of the test solution L, and set the obtained TOC value as the total organic carbon concentration W0 of the water-soluble polymer to be measured contained in the test solution L; (3) perform centrifugation treatment on the test solution L at 26,000 rpm for 30 minutes to separate it into a precipitate and a supernatant, measure the TOC value of the supernatant, and set the obtained TOC value as the total organic carbon concentration W1 of the water-soluble polymer to be measured contained in the supernatant; (4) calculate the adsorption ratio of the water-soluble polymer to be measured by the following formula, and this value It is used as a particle adsorption parameter.

Images