JP7645325B2 - RINSE COMPOSITION AND RINSE METHOD - Google Patents

Description

The present invention relates to a rinsing composition used to rinse an object to be polished after polishing, and a method for rinsing an object to be polished using the rinsing composition.

Precision polishing is performed on the surfaces of materials such as metals, semi-metals, non-metals, and oxides thereof using a polishing composition containing abrasive grains. For example, the surface of a silicon wafer used as a component of a semiconductor device is generally finished into a high-quality mirror surface through a lapping process (rough polishing process) and a polishing process (precision polishing process). The polishing process typically includes a preliminary polishing process (preliminary polishing process) and a finish polishing process (final polishing process). Patent documents 1 to 3 are examples of technical documents related to polishing semiconductor substrates such as silicon wafers.

JP 2017-183478 A International Publication No. 2016/129215 Patent No. 6193959

When an object to be polished is polished using a polishing composition containing abrasive grains, the abrasive grains contained in the polishing composition usually adhere to the surface of the object to be polished after polishing. Since there are various problems if the abrasive grains remain attached to the surface of the object to be polished, it is common to rinse the surface of the object to be polished after polishing with a rinsing composition in order to remove the attached abrasive grains.
In recent years, the demand for surface quality after polishing by a finish polishing process (particularly, a finish polishing process for semiconductor substrates such as silicon wafers and other substrates) has become higher. In order to realize a high-quality surface after polishing, a rinsing composition used after polishing is required to have the performance of protecting the surface of the object to be polished well during rinsing, reducing the number of PIDs (Polish Induced Defects) after polishing, and reliably removing abrasive grains and the like attached to the surface of the object to be polished after rinsing. However, conventional rinsing compositions do not fully satisfy these demands, and there is still room for improvement.

The present invention therefore aims to provide a rinsing composition that contains a water-soluble polymer and does not contain abrasive grains, and that can reduce the number of defects on an object to be polished after polishing. Another related object is to provide a method for rinsing an object to be polished after polishing using such a rinsing composition.

In this specification, reducing the number of defects refers to reducing the number of defects called LLS (Localized Light Scatterers). A surface defect inspection device is used to measure LLS. A typical surface defect inspection device detects the presence and size of defects by irradiating the surface of the object to be polished with light such as laser light, receiving and analyzing the reflected light as a signal. The LLS detected by the surface defect inspection device include foreign matter and residues on the object to be polished that were not completely removed in the polishing process, rinsing process, and cleaning process, i.e., PID and abrasive grain residue. A defect review SEM (Scanning Electron Microscope) or the like is used to analyze the defect type of the detected LLS.

The rinse composition provided by this specification is a rinse composition containing a water-soluble polymer and no abrasive grains, wherein the water-soluble polymer is a compound represented by the following formula (I):
W1/W0×100 (I);
The present invention is characterized in that the composition contains a water-soluble polymer A having a desorption parameter of 150 or more, as expressed by the following formula: W0 in the above formula (I) is the static contact angle, with deionized water, of a wafer before SC-1 cleaning treatment, obtained by applying an aqueous solution of the water-soluble polymer to the surface of a silicon wafer and then rinsing with water. W1 in the above formula (I) is the static contact angle, with deionized water, of a wafer after SC-1 treatment, obtained by subjecting the wafer before SC-1 cleaning treatment to cleaning treatment (specifically, cleaning treatment for 10 seconds with a room temperature SC-1 cleaning solution containing 29% ammonia water, 31% hydrogen peroxide solution, and water in a volume ratio of 0.5:0.5:8). In this specification, the contact angle is expressed in units of "degrees (°)". In addition, in this specification, the concentration and content are expressed by weight unless otherwise specified. Rinsing with a rinsing composition containing the water-soluble polymer A can reduce the number of defects on the polishing object. For example, the number of abrasive grain residues can be reduced, and the number of PIDs can be reduced.

In some embodiments of the rinsing composition disclosed herein, the rinsing composition further contains a water-soluble polymer B having a desorption parameter represented by the above formula (I) of less than 150. In such a configuration of the rinsing composition, the number of defects on the object to be polished can be further effectively reduced.

As the water-soluble polymer A, a water-soluble polymer containing a nitrogen atom-containing polymer can be preferably used. In this embodiment, the number of defects on the polished object after rinsing can be suitably reduced.

In some embodiments of the rinsing composition disclosed herein, the rinsing composition further comprises a surfactant. Such a rinsing composition can further effectively reduce the number of defects on the surface of the polishing object after rinsing.

In some embodiments of the rinsing composition disclosed herein, the rinsing composition further contains a basic compound. Such a rinsing composition can effectively reduce the number of defects on the object to be polished.

This specification also provides a rinsing method including a rinsing step in which an object to be polished that has been polished in a polishing step using a polishing composition containing abrasive grains is rinsed by supplying a rinsing liquid containing any of the rinsing compositions disclosed herein. The rinsing method described above can effectively reduce the number of defects in the object to be polished after rinsing.

In some aspects of the rinsing method disclosed herein, in the rinsing step, it is preferable to supply the rinsing liquid to the object to be polished on the platen of the polishing device used in the polishing step. The effect of reducing the number of defects in the object to be polished can be more effectively achieved in such aspects.

The rinsing method disclosed herein can be preferably used to rinse silicon wafers that have been polished using a polishing composition containing abrasive grains. By performing rinsing using this method after the polishing process, surface defects can be reduced, and a high-quality silicon wafer surface can be preferably achieved.

The following describes preferred embodiments of the present invention. Note that matters other than those specifically mentioned in this specification that are necessary for implementing the present invention can be understood as design matters for a person skilled in the art based on the prior art in the relevant field. The present invention can be implemented based on the contents disclosed in this specification and common technical knowledge in the relevant field.

<Water-soluble polymer>
The rinse composition disclosed herein includes a water-soluble polymer. The water-soluble polymer can be useful for protecting the surface of the object to be polished. As the water-soluble polymer, a polymer having at least one functional group selected from a cationic group, an anionic group, and a nonionic group in the molecule can be used alone or in combination of two or more. More specifically, for example, one or more polymers selected from polymers having a hydroxyl group, a carboxyl group, an acyloxy group, a sulfo group, an amide structure, an imide structure, a vinyl structure, a heterocyclic structure, etc. in the molecule can be used as the water-soluble polymer. The water-soluble polymer can include water-soluble polymers such as nitrogen atom-containing polymers, vinyl alcohol-based polymers, polymers containing oxyalkylene units, cellulose derivatives, and starch derivatives.

As the polymer containing nitrogen atoms, both a polymer containing nitrogen atoms in the main chain and a polymer having nitrogen atoms in a side chain functional group (pendant group) can be used. Examples of the polymer containing nitrogen atoms in the main chain include homopolymers and copolymers of N-acyl alkylene imine type monomers. Specific examples of N-acyl alkylene imine type monomers include N-acetyl ethylene imine, N-propionyl ethylene imine, and the like. Examples of the polymer having nitrogen atoms in the pendant group include, for example, polymers containing N-vinyl type monomer units. For example, homopolymers and copolymers of N-vinyl pyrrolidone can be employed. Non-limiting examples of the polymer containing nitrogen atoms include polymers containing N-vinyl type monomer units such as N-vinyl lactams and N-vinyl linear amides; imine derivatives; polymers containing N-(meth)acryloyl type monomer units; and the like.

Examples of polymers containing N-vinyl type monomer units include polymers containing repeating units derived from monomers having a nitrogen-containing heterocycle. An example of a nitrogen-containing heterocycle is a lactam ring. Examples of polymers containing such repeating units include homopolymers and copolymers of N-vinyl lactam type monomers, and homopolymers and copolymers of N-vinyl linear amides. The N-vinyl lactam type monomer copolymer may be, for example, a copolymer in which the copolymerization ratio of N-vinyl lactam type monomer exceeds 50% by weight. The N-vinyl linear amide copolymer may be, for example, a copolymer in which the copolymerization ratio of N-vinyl linear amide exceeds 50% by weight.

In this specification, unless otherwise specified, the term "copolymer" refers collectively to various copolymers such as random copolymers, alternating copolymers, block copolymers, and graft copolymers. From the viewpoint of more uniformly protecting the surface of the object to be polished during rinsing, random copolymers can be preferably used in some embodiments. In particular, when a copolymer is used as a water-soluble polymer, a random copolymer can be preferably used as the copolymer.

Specific examples of N-vinyl lactam type monomers include N-vinyl pyrrolidone (VP), N-vinyl piperidone, N-vinyl morpholinone, N-vinyl caprolactam (VC), N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholinedione. Specific examples of polymers containing N-vinyl lactam type monomer units include polyvinyl pyrrolidone, polyvinyl caprolactam, random copolymers of VP and VC, random copolymers of one or both of VP and VC with other vinyl monomers, block copolymers and graft copolymers containing polymer chains containing one or both of VP and VC. The other vinyl monomers may be, for example, acrylic monomers, vinyl ester monomers, and the like. The acrylic monomers herein refer to monomers having a (meth)acryloyl group. Specific examples of N-vinyl chain amides include N-vinyl acetamide, N-vinyl propionic acid amide, and N-vinyl butyric acid amide.

Examples of polymers containing N-(meth)acryloyl type monomer units include homopolymers and copolymers of N-(meth)acryloyl type monomers. Examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. The copolymers of the above-mentioned N-(meth)acryloyl type monomers may be, for example, copolymers in which the copolymerization ratio of N-(meth)acryloyl type monomers exceeds 50% by weight.

Examples of chain amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, and N-n-butyl (meth)acrylamide; and N,N-dialkyl (meth)acrylamides such as N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, and N,N-di(n-butyl) (meth)acrylamide. Examples of polymers containing chain amides having an N-(meth)acryloyl group as monomer units include homopolymers of N-isopropylacrylamide and copolymers of N-isopropylacrylamide. The copolymers of N-isopropylacrylamide may be, for example, copolymers in which the copolymerization ratio of N-isopropylacrylamide exceeds 50% by weight.

Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine. Examples of polymers containing cyclic amides having an N-(meth)acryloyl group as monomer units include homopolymers of N-acryloylmorpholine and copolymers of N-acryloylmorpholine. The above-mentioned copolymers of N-acryloylmorpholine may be, for example, copolymers in which the copolymerization ratio of N-acryloylmorpholine exceeds 50% by weight.

As the vinyl alcohol-based polymer, a water-soluble organic substance (typically a water-soluble polymer) containing a vinyl alcohol unit as a repeating unit is used. Here, the vinyl alcohol unit (hereinafter also referred to as "VA unit") is a structural portion represented by the following chemical formula: -CH ₂ -CH(OH)-. The vinyl alcohol-based polymer may contain only VA units as repeating units, or may contain repeating units other than VA units (hereinafter also referred to as "non-VA units") in addition to VA units. The vinyl alcohol-based polymer may be a random copolymer containing VA units and non-VA units, or may be a block copolymer or a graft copolymer. The vinyl alcohol-based polymer may contain only one type of non-VA unit, or may contain two or more types of non-VA units.

The vinyl alcohol-based polymer used in the rinse composition disclosed herein may be unmodified polyvinyl alcohol (unmodified PVA) or modified polyvinyl alcohol (modified PVA). Unmodified PVA here refers to a vinyl alcohol-based polymer that is produced by hydrolysis (saponification) of polyvinyl acetate and does not substantially contain repeating units other than repeating units (-CH ₂ -CH(OCOCH ₃ )-) having a structure in which vinyl acetate is vinyl-polymerized and VA units. The degree of saponification of the unmodified PVA may be, for example, 60% or more, and from the viewpoint of water solubility, may be 70% or more, 80% or more, or 90% or more. In some embodiments, unmodified PVA having a degree of saponification of 95% or more or 98% or more may be preferably used as the water-soluble polymer compound.

The vinyl alcohol polymer may be a modified PVA containing VA units and non-VA units (e.g., non-VA units having at least one structure selected from an oxyalkylene group, a carboxy group, a sulfo group, an amino group, a hydroxyl group, an amide group, an imide group, a nitrile group, an ether group, an ester group, and salts thereof). Examples of non-VA units that may be contained in the modified PVA include, but are not limited to, repeating units derived from N-vinyl monomers and N-(meth)acryloyl monomers described below, repeating units derived from ethylene, repeating units derived from alkyl vinyl ethers, and repeating units derived from vinyl esters of monocarboxylic acids having 3 or more carbon atoms. A suitable example of the N-vinyl monomer is N-vinylpyrrolidone. A suitable example of the N-(meth)acryloyl monomer is N-(meth)acryloylmorpholine. The alkyl vinyl ether may be, for example, a vinyl ether having an alkyl group having 1 to 10 carbon atoms, such as propyl vinyl ether, butyl vinyl ether, or 2-ethylhexyl vinyl ether. The vinyl ester of a monocarboxylic acid having 3 or more carbon atoms may be, for example, a vinyl ester of a monocarboxylic acid having 3 to 7 carbon atoms, such as vinyl propanoate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate.

The vinyl alcohol polymer may be a modified PVA in which a part of the VA units contained in the vinyl alcohol polymer is acetalized with an aldehyde. Examples of the aldehyde include formaldehyde; linear or branched alkyl aldehydes such as acetaldehyde, propionaldehyde, n-butyl aldehyde, isobutyl aldehyde, t-butyl aldehyde, and hexyl aldehyde; alicyclic or aromatic aldehydes such as cyclohexanecarbaldehyde and benzaldehyde; and the like. These may be used alone or in combination of two or more. In addition, except for formaldehyde, one or more hydrogen atoms may be substituted with a halogen or the like. Among these, linear or branched alkyl aldehydes are preferred in terms of high solubility in water and easy acetalization reaction. Among them, preferred aldehydes include acetaldehyde, n-propylaldehyde, n-butylaldehyde, and n-pentylaldehyde. In addition to the above, aldehyde compounds having 8 or more carbon atoms, such as 2-ethylhexylaldehyde, nonylaldehyde, and decylaldehyde, may also be used.
As the vinyl alcohol polymer, a cationically modified polyvinyl alcohol having a cationic group such as a quaternary ammonium structure introduced therein may be used. Examples of the cationically modified polyvinyl alcohol include those having a cationic group derived from a monomer having a cationic group such as a diallyldialkylammonium salt or an N-(meth)acryloylaminoalkyl-N,N,N-trialkylammonium salt introduced therein.

The ratio of the number of moles of VA units to the number of moles of all repeating units constituting the vinyl alcohol-based polymer may be, for example, 5% or more, 10% or more, 20% or more, or 30% or more. Although not particularly limited, in some embodiments, the ratio of the number of moles of the VA units may be 50% or more, 65% or more, 75% or more, 80% or more, or 90% or more (e.g., 95% or more, or 98% or more). Substantially 100% of the repeating units constituting the vinyl alcohol-based polymer may be VA units. Here, "substantially 100%" means that the vinyl alcohol-based polymer does not contain non-VA units at least intentionally, and typically includes the case where the ratio of the number of moles of non-VA units to the number of moles of all repeating units is less than 2% (e.g., less than 1%), and 0%. In some other embodiments, the ratio of the number of moles of VA units to the number of moles of all repeating units constituting the vinyl alcohol-based polymer may be, for example, 95% or less, 90% or less, 80% or less, or 70% or less.

The content of VA units in the vinyl alcohol-based polymer (content by weight) may be, for example, 5% by weight or more, 10% by weight or more, 20% by weight or more, or 30% by weight or more. Although not particularly limited, in some embodiments, the content of the VA units may be 50% by weight or more (e.g., more than 50% by weight), 70% by weight or more, or 80% by weight or more (e.g., 90% by weight or more, 95% by weight or more, or 98% by weight or more). Substantially 100% by weight of the repeating units constituting the vinyl alcohol-based polymer may be VA units. Here, "substantially 100% by weight" means that at least intentionally, non-VA units are not contained as repeating units constituting the vinyl alcohol-based polymer, and typically means that the content of non-VA units in the vinyl alcohol-based polymer is less than 2% by weight (e.g., less than 1% by weight). In some other embodiments, the content of VA units in the vinyl alcohol-based polymer may be, for example, 95% by weight or less, 90% by weight or less, 80% by weight or less, or 70% by weight or less.

A vinyl alcohol-based polymer may contain multiple polymer chains with different VA unit contents within the same molecule. Here, a polymer chain refers to a portion (segment) that constitutes a part of a single polymer molecule. For example, a vinyl alcohol-based polymer may contain, within the same molecule, polymer chain A with a VA unit content of more than 50% by weight and polymer chain B with a VA unit content of less than 50% by weight (i.e., a non-VA unit content of more than 50% by weight).

Polymer chain A may contain only VA units as repeating units, or may contain non-VA units in addition to VA units. The content of VA units in polymer chain A may be 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. In some embodiments, the content of VA units in polymer chain A may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting polymer chain A may be VA units.

Polymer chain B may contain only non-VA units as repeating units, or may contain VA units in addition to non-VA units. The content of non-VA units in polymer chain B may be 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. In some embodiments, the content of non-VA units in polymer chain B may be 95% by weight or more, or 98% by weight or more. Substantially 100% by weight of the repeating units constituting polymer chain B may be non-VA units.

Examples of vinyl alcohol-based polymers containing polymer chain A and polymer chain B in the same molecule include block copolymers and graft copolymers containing these polymer chains. The graft copolymer may be a graft copolymer having a structure in which polymer chain B (side chain) is grafted to polymer chain A (main chain), or a graft copolymer having a structure in which polymer chain A (side chain) is grafted to polymer chain B (main chain). In one embodiment, a vinyl alcohol-based polymer having a structure in which polymer chain B is grafted to polymer chain A can be used.

Examples of polymer chain B include polymer chains whose main repeating units are repeating units derived from N-vinyl type monomers, polymer chains whose main repeating units are repeating units derived from N-(meth)acryloyl type monomers, and polymer chains whose main repeating units are oxyalkylene units. In this specification, the term "main repeating unit" refers to a repeating unit that is contained in an amount of more than 50% by weight, unless otherwise specified.

A suitable example of polymer chain B is a polymer chain having an N-vinyl type monomer as the main repeating unit, i.e., an N-vinyl polymer chain. The content of repeating units derived from N-vinyl type monomers in the N-vinyl polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or 95% by weight or more. Substantially all of polymer chain B may be repeating units derived from N-vinyl type monomers.

In this specification, examples of N-vinyl type monomers include monomers having a nitrogen-containing heterocycle (e.g., lactam ring) and N-vinyl chain amides. Specific examples of N-vinyl lactam type monomers include N-vinyl pyrrolidone, N-vinyl piperidone, N-vinyl morpholinone, N-vinyl caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, and the like. Specific examples of N-vinyl chain amides include N-vinyl acetamide, N-vinyl propionic acid amide, N-vinyl butyric acid amide, and the like. Polymer chain B may be, for example, an N-vinyl polymer chain in which more than 50% by weight (e.g., 70% by weight or more, 85% by weight or more, or 95% by weight or more) of its repeating units are N-vinyl pyrrolidone units. Substantially all of the repeating units constituting polymer chain B may be N-vinyl pyrrolidone units.

Another example of polymer chain B is a polymer chain whose main repeating unit is a repeating unit derived from an N-(meth)acryloyl type monomer, i.e., an N-(meth)acryloyl-based polymer chain. The content of repeating units derived from N-(meth)acryloyl type monomers in the N-(meth)acryloyl-based polymer chain is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or 95% by weight or more. Substantially all of polymer chain B may be repeating units derived from N-(meth)acryloyl type monomers.

In this specification, examples of N-(meth)acryloyl type monomers include linear amides having an N-(meth)acryloyl group and cyclic amides having an N-(meth)acryloyl group. Examples of linear amides having an N-(meth)acryloyl group include (meth)acrylamide; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-n-butyl(meth)acrylamide; and N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di(n-butyl)(meth)acrylamide. Examples of cyclic amides having an N-(meth)acryloyl group include N-(meth)acryloylmorpholine and N-(meth)acryloylpyrrolidine.

Other examples of polymer chain B include polymer chains containing oxyalkylene units as the main repeating units, i.e., oxyalkylene-based polymer chains. The content of oxyalkylene units in the oxyalkylene-based polymer chains is typically more than 50% by weight, and may be 70% by weight or more, 85% by weight or more, or 95% by weight or more. Substantially all of the repeating units contained in polymer chain B may be oxyalkylene units.

Examples of oxyalkylene units include oxyethylene units, oxypropylene units, and oxybutylene units. Each of these oxyalkylene units may be a repeating unit derived from the corresponding alkylene oxide. The oxyalkylene units contained in the oxyalkylene polymer chain may be one type, or two or more types. For example, the oxyalkylene polymer chain may contain a combination of oxyethylene units and oxypropylene units. In an oxyalkylene polymer chain containing two or more types of oxyalkylene units, the oxyalkylene units may be a random copolymer of the corresponding alkylene oxide, or may be a block copolymer or a graft copolymer.

Further examples of polymer chain B include polymer chains containing repeating units derived from alkyl vinyl ethers (e.g., vinyl ethers having an alkyl group with 1 to 10 carbon atoms), polymer chains containing repeating units derived from monocarboxylic acid vinyl esters (e.g., vinyl esters of monocarboxylic acids with 3 or more carbon atoms), polymer chains in which some of the VA units have been acetalized with an aldehyde (e.g., an alkyl aldehyde having an alkyl group with 1 to 7 carbon atoms), and polymer chains into which a cationic group (e.g., a cationic group having a quaternary ammonium structure) has been introduced.

As the vinyl alcohol-based polymer in the rinse composition disclosed herein, a non-modified PVA may be used, a modified PVA may be used, or a combination of a non-modified PVA and a modified PVA may be used. In an embodiment in which a non-modified PVA and a modified PVA are used in combination, the amount of modified PVA used relative to the total amount of vinyl alcohol-based polymer contained in the rinse composition may be, for example, less than 50% by weight, 30% by weight or less, 10% by weight or less, 5% by weight or less, or 1% by weight or less. The rinse composition disclosed herein may be preferably implemented, for example, in an embodiment in which only one or more types of non-modified PVA are used as the vinyl alcohol-based polymer.

Examples of the polymer containing an oxyalkylene unit include polyethylene oxide (PEO), block copolymers of ethylene oxide (EO) and propylene oxide (PO) or butylene oxide (BO), and random copolymers of EO and PO or BO. Among these, block copolymers of EO and PO or random copolymers of EO and PO are preferred. The block copolymers of EO and PO may be diblock copolymers or triblock copolymers containing a PEO block and a polypropylene oxide (PPO) block. Examples of the triblock copolymers include PEO-PPO-PEO type triblock copolymers and PPO-PEO-PPO type triblock copolymers. Among these, PEO-PPO-PEO type triblock copolymers are more preferred.
In a block copolymer or random copolymer of EO and PO, the molar ratio of EO to PO (EO/PO) constituting the copolymer is preferably greater than 1, more preferably 2 or more, and even more preferably 3 or more (e.g., 5 or more), from the viewpoints of solubility in water, washability, etc.

Cellulose derivatives are polymers that contain β-glucose units as the main repeating unit, such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose (HEC), methylhydroxyethyl cellulose, etc. Starch derivatives are polymers that contain α-glucose units as the main repeating unit, such as pregelatinized starch, pullulan, carboxymethyl starch, cyclodextrin, etc.

(Water-soluble polymer A)
The rinsing composition disclosed herein is characterized by including, as the water-soluble polymer, at least one water-soluble polymer A having a desorption parameter of 150 or more. The desorption parameter is determined as a percentage of the static contact angle W1 of the surface of a silicon wafer coated with the water-soluble polymer to be evaluated, with deionized water, relative to the static contact angle W0 of the surface of the silicon wafer, after the silicon wafer is treated with an SC-1 cleaning solution for 10 seconds. More specifically, the desorption parameter is measured by the following method.

[Method of measuring desorption parameters]
(1) A test piece (hereinafter simply referred to as the test piece) cut into a size of 30 mm x 60 mm from a commercially available silicon single crystal wafer (conductivity type: P type, crystal orientation: <100>, COP (Crystal Originated Particle) free) with a diameter of 300 mm is first treated with an SC-1 cleaning solution and then immersed in a 2.5% hydrogen fluoride (HF) aqueous solution for 30 seconds to perform a pretreatment to remove the surface oxide film.
(2) Prepare a test solution containing the water-soluble polymer to be evaluated at a concentration of 0.18% and adjusted to pH 10 with ammonia. Place the test piece in a petri dish and pour in the test solution so that the test piece is immersed. Place a mixed nonwoven fabric of polyester and cellulose on top of the test piece and rotate it at a speed of 60 rpm for 1 minute while applying a load of 1 kg. After applying the test solution to the test piece in this way, immerse the test piece in deionized water to remove excess water-soluble polymer.
(3) The test piece is immersed in a 2.5% HF aqueous solution for 30 seconds to remove the surface oxide film formed in the above step (2).
(4) The static contact angle W0 of the test piece (wafer before SC-1 processing) to deionized water is measured within 3 seconds after being exposed to the deionized bath liquid.
(5) The test piece is subjected to a cleaning process in which it is immersed in deionized water and then treated with SC-1 cleaning solution for 10 seconds, and then immersed in deionized water and further in a 2.5% HF aqueous solution for 30 seconds to remove the surface oxide film.
(6) The static contact angle W1 of the test piece (wafer after SC-1 treatment) with deionized water is measured within 3 seconds after the deionized bath liquid is applied.
(7) From the thus obtained W0 and W1, the desorption parameter is calculated by the following formula: W1/W0×100.

In the above steps (1) and (5), the treatment with the SC-1 cleaning solution can be suitably carried out by placing the SC-1 cleaning solution, which is a mixture of 29% ammonia water, 31% hydrogen peroxide water, and deionized water in a volume ratio of 0.5:0.5:8, in a cleaning tank and immersing the test piece in this cleaning solution at room temperature. However, the above treatment conditions can be appropriately changed depending on the initial state of the test piece to be used so that the static contact angles W0 and W1 can be measured appropriately.

In addition, in steps (4) and (6) above, the contact angle measuring device may be a contact angle meter such as DropMaster DMo-501 manufactured by Kyowa Interface Science Co., Ltd. or an equivalent product.

The surface of a clean silicon wafer is hydrophobic. Water-soluble polymers attached to the surface of a silicon wafer reduce the static contact angle with deionized water. For this reason, water-soluble polymers with a small W0 value are considered to protect the test piece surface well. On the other hand, water-soluble polymers with a large W1 value tend to be easily removed by cleaning treatment using an SC-1 cleaning solution (hereinafter also referred to as SC-1 treatment). Therefore, the desorption parameter can be an indicator of the surface protection effect of the water-soluble polymer and the ease of removing the water-soluble polymer by SC-1 treatment.

The reason why the above-mentioned effect of reducing the number of surface defects can be obtained by rinsing with a rinsing composition containing a water-soluble polymer A having a desorption parameter of 150 or more is not particularly limited, but it is believed that a water-soluble polymer with a high desorption parameter reduces the number of PIDs by protecting the surface of the object to be polished well during rinsing, and is easily removed together with the abrasive grains contained in the polishing composition in the SC-1 cleaning solution treatment, thereby reducing the number of abrasive grain residues. As a result, the above-mentioned rinsing composition can suitably achieve both a reduction in the number of PIDs and a reduction in the number of abrasive grain residues. By rinsing an object to be polished that has been polished with a polishing composition using such a rinsing composition containing a water-soluble polymer A, the number of defects on the object to be polished can be reduced. From this perspective, in some embodiments, the desorption parameter of the water-soluble polymer A may be, for example, 170 or more, 200 or more, or 300 or more.

The water-soluble polymer A is not particularly limited as long as it has a desorption parameter of 150 or more, and one or more of the known water-soluble polymers described above may be appropriately selected and used. In some embodiments, a nonionic polymer may be preferably used as the water-soluble polymer A, since it is easy to obtain a polymer that exhibits the preferred desorption parameters disclosed herein.
For example, the water-soluble polymer A may be selected from the above-mentioned vinyl alcohol-based polymers, polymers containing oxyalkylene units, nitrogen-containing polymers, cellulose derivatives, starch derivatives, and the like, which have an elimination parameter of 150 or more. In some embodiments, a nitrogen-containing polymer may be preferably selected as the water-soluble polymer A. Among these, a nitrogen-containing polymer containing an N-(meth)acryloyl-type monomer unit, such as a linear or cyclic amide having an N-(meth)acryloyl group, is preferred.

The content (weight-based content) of the water-soluble polymer A in the rinse composition is not particularly limited. For example, it can be 1.0×10 ⁻⁴ wt % or more. From the viewpoint of reducing the number of defects, the content is preferably 2.0×10 ⁻⁴ wt % or more, more preferably 5.0×10 ⁻⁴ wt % or more, even more preferably 1.0×10 ⁻³ wt % or more, for example 2.0×10 ⁻³ wt % or more. From the viewpoint of cleaning efficiency, the content is preferably 0.2 wt % or less, more preferably 0.1 wt % or less, and even more preferably 0.05 wt % or less (for example, 0.02 wt % or less). In addition, when the rinse composition contains two or more water-soluble polymers having a desorption parameter of 150 or more, the content of the water-soluble polymer A refers to the total content (weight-based content) of all water-soluble polymers having a desorption parameter of 150 or more contained in the rinse composition.

The weight average molecular weight (Mw) of the water-soluble polymer A is not particularly limited. From the viewpoint of easily obtaining the suitable desorption parameters disclosed herein, the Mw of the water-soluble polymer A is usually preferably 200×10 ⁴ or less, 150×10 ⁴ or less, or 100×10 ⁴ or less. From the viewpoint of improving cleaning properties, in some embodiments, the Mw of the water-soluble polymer A may be, for example, 50×10 ⁴ or less, 30×10 ⁴ or less, 20×10 ⁴ or less, 10×10 ⁴ or less, 5×10 ⁴ or less, or 3×10 ⁴ or less. In addition, from the viewpoint of easily obtaining the effect of reducing the number of defects, the Mw of the water-soluble polymer A is usually appropriately 2000 or more, may be 3000 or more, or may be 3500 or more. The technology disclosed herein may also be implemented in an embodiment using a water-soluble polymer A having an Mw of 1×10 ⁴ or more or 2×10 ⁴ or more. In this specification, the weight average molecular weight of the water-soluble polymer and the surfactant described later can be a value based on aqueous gel permeation chromatography (GPC) (aqueous, polyethylene oxide equivalent) or a molecular weight calculated from a chemical formula. As a GPC measuring device, it is recommended to use a model named "HLC-8320GPC" manufactured by Tosoh Corporation. The measurement can be performed, for example, under the following conditions. The same method is also used in the examples described later.
[GPC measurement conditions]
Sample concentration: 0.1% by weight
Column: TSKgel GMPWXL
Detector: differential refractometer Eluent: 100 mM sodium nitrate aqueous solution/acetonitrile = 10-8/0-2
Flow rate: 1mL/min Measurement temperature: 40℃
Sample injection volume: 200 μL

(Water-soluble polymer B)
The rinsing composition disclosed herein may contain, as the water-soluble polymer, in addition to the water-soluble polymer A having a desorption parameter of 150 or more, a water-soluble polymer B having a desorption parameter of less than 150. A rinsing composition further containing the water-soluble polymer B in combination with the water-soluble polymer A is preferred from the viewpoint of surface protection of the object to be polished during rinsing, and is also preferred from the viewpoint of ease of removal by SC-1 treatment after rinsing, reduction in the number of abrasive grain residues, etc. From such a viewpoint, in some embodiments, the desorption parameter of the water-soluble polymer B may be, for example, less than 140, 130 or less, or 120 or less.

The water-soluble polymer B is not particularly limited as long as the desorption parameter is less than 150, and one or more of the above-mentioned known water-soluble polymers may be appropriately selected and used. In some embodiments, a nonionic polymer may be preferably used as the water-soluble polymer B.
For example, the water-soluble polymer B may be selected from the above-mentioned vinyl alcohol-based polymers, polymers containing oxyalkylene units, nitrogen atom-containing polymers, cellulose derivatives, starch derivatives, etc., which have a detachment parameter of less than 150. In some embodiments, a vinyl alcohol-based polymer may be preferably used as the water-soluble polymer B. A preferred example of the rinsing composition disclosed herein is a rinsing composition that includes a nitrogen atom-containing polymer having a detachment parameter of 150 or more as the water-soluble polymer A, and further includes a vinyl alcohol-based polymer having a detachment parameter of less than 150 as the water-soluble polymer B.

When the rinse composition disclosed herein contains a water-soluble polymer B, the content of the water-soluble polymer B in the rinse composition (content based on weight, when two or more kinds of water-soluble polymers B are contained, the total content thereof) is not particularly limited. For example, it can be 1.0×10 ⁻⁴ wt % or more. From the viewpoint of reducing the number of defects, etc., the content is preferably 2.0×10 ⁻⁴ wt % or more, more preferably 5.0×10 ⁻⁴ wt % or more, even more preferably 1.0×10 ⁻³ wt % or more, for example, 2.0×10 ⁻³ wt % or more. From the viewpoint of cleaning efficiency, etc., the content is preferably 0.2 wt % or less, more preferably 0.1 wt % or less, and even more preferably 0.05 wt % or less (for example, 0.02 wt % or less).

The proportion of the content of water-soluble polymer B in the total content of water-soluble polymers contained in the rinse composition (when two or more types of water-soluble polymer B are contained, the total content of them) may be, for example, 25% by weight or more, preferably 40% by weight or more, 50% by weight or more, more than 50% by weight, 70% by weight or more, 80% by weight or more, or 95% by weight or more. In this specification, the total content of water-soluble polymers refers to the total content (content by weight) of all water-soluble polymers contained in the rinse composition.

The weight average molecular weight (Mw) of the water-soluble polymer B is not particularly limited. Usually, the Mw of the water-soluble polymer B is preferably 200×10 ⁴ or less, 150×10 ⁴ or less, or 100×10 ⁴ or less. From the viewpoint of improving cleaning properties, in some embodiments, the Mw of the water-soluble polymer B may be, for example, 50×10 ⁴ or less, 30×10 ⁴ or less, 20×10 ⁴ or less, 10×10 ⁴ or less, 5×10 ⁴ or less, or 3×10 ⁴ or less. Also, from the viewpoint of easily obtaining the effect of reducing the number of defects in the polishing object after rinsing in combination with the water-soluble polymer A, the Mw of the water-soluble polymer B is usually appropriate to be 2000 or more, may be 3000 or more, or may be 3500 or more. The technology disclosed herein may also be implemented in an embodiment using a water-soluble polymer B having an Mw of 1×10 ⁴ or more or 2×10 ⁴ or more.

<Basic Compound>
The rinse composition disclosed herein may further contain a basic compound. In this specification, the basic compound refers to a compound that dissolves in water and has the function of increasing the pH of the aqueous solution. The basic compound may be used alone or in combination of two or more.
Examples of the basic compound that can be used include organic or inorganic basic compounds containing nitrogen, basic compounds containing phosphorus, hydroxides of alkali metals, hydroxides of alkaline earth metals, various carbonates and hydrogen carbonates, etc. Examples of the basic compound containing nitrogen include quaternary ammonium compounds, ammonia, amines (preferably water-soluble amines), etc. Examples of the basic compound containing phosphorus include quaternary phosphonium compounds.

Specific examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Specific examples of carbonates or hydrogen carbonates include ammonium hydrogen carbonate, ammonium carbonate, potassium hydrogen carbonate, potassium carbonate, sodium hydrogen carbonate, and sodium carbonate. Specific examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, anhydrous piperazine, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, guanidine, and azoles such as imidazole and triazole. Specific examples of quaternary phosphonium compounds include quaternary phosphonium hydroxides such as tetramethylphosphonium hydroxide and tetraethylphosphonium hydroxide.

As the quaternary ammonium compound, quaternary ammonium salts (typically strong bases) such as tetraalkylammonium salts and hydroxyalkyltrialkylammonium salts can be preferably used. The anion component in such quaternary ammonium salts can be, for example, OH ^- , F ^- , Cl ^- , Br ^- , I ^- , ClO ₄ ^- , BH ₄ ^- , etc. Among them, preferred examples include quaternary ammonium salts whose anion is OH ^- , that is, quaternary ammonium hydroxides. Specific examples of quaternary ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, and tetrahexylammonium hydroxide; hydroxyalkyltrialkylammonium hydroxides such as 2-hydroxyethyltrimethylammonium hydroxide (also called choline); and the like.

Among these basic compounds, at least one basic compound selected from, for example, alkali metal hydroxides, quaternary ammonium hydroxides, and ammonia can be preferably used. Among these, potassium hydroxide, tetraalkylammonium hydroxide (for example, tetramethylammonium hydroxide), and ammonia are more preferable, and ammonia is particularly preferable.

<Surfactant>
The rinsing composition disclosed herein may contain a surfactant as necessary. By adding a surfactant to the rinsing composition, the number of defects on the surface of the polishing object after rinsing can be reduced. Any of anionic, cationic, nonionic, and amphoteric surfactants can be used as the surfactant. Usually, anionic or nonionic surfactants can be preferably used. From the viewpoint of low foaming and ease of pH adjustment, nonionic surfactants are more preferable. For example, nonionic surfactants include oxyalkylene polymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyoxyalkylene derivatives such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene fatty acid esters, polyoxyethylene glyceryl ether fatty acid esters, and polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyalkylene adducts); and copolymers of multiple types of oxyalkylenes (e.g., diblock copolymers, triblock copolymers, random copolymers, and alternating copolymers). The surfactant preferably includes a surfactant containing a polyoxyalkylene structure. The surfactants can be used alone or in combination of two or more.

Specific examples of nonionic surfactants containing a polyoxyalkylene structure include block copolymers of ethylene oxide (EO) and propylene oxide (PO) (diblock copolymers, PEO (polyethylene oxide)-PPO (polypropylene oxide)-PEO type triblock copolymers, PPO-PEO-PPO type triblock copolymers, etc.), random copolymers of EO and PO, polyoxyethylene glycol, 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 tetra ... Examples of the polyoxyethylene oleyl ether include polyoxyethylene phenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, polyoxyethylene dioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitoate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil. Among these, preferred surfactants include block copolymers of EO and PO (particularly triblock copolymers of the PEO-PPO-PEO type), random copolymers of EO and PO, and polyoxyethylene alkyl ethers (e.g., polyoxyethylene decyl ether).

The weight average molecular weight (Mw) of the surfactant is typically less than 2000, and is preferably 1900 or less (e.g., less than 1800) from the viewpoint of cleaning properties. In addition, the Mw of the surfactant is usually appropriate to be 200 or more from the viewpoint of surface activity, and is preferably 250 or more (e.g., 300 or more) from the viewpoint of the effect of reducing the number of defects. The more preferable range of the Mw of the surfactant may vary depending on the type of the surfactant. For example, when a polyoxyethylene alkyl ether is used as the surfactant, the Mw is preferably 1500 or less, and may be 1000 or less (e.g., 500 or less). In addition, when a PEO-PPO-PEO type triblock copolymer is used as the surfactant, the Mw may be, for example, 500 or more, 1000 or more, or even 1200 or more.

When the rinse composition disclosed herein contains a surfactant, the content is not particularly limited as long as it is within a range that does not significantly impair the effects of the present invention. Usually, from the viewpoint of cleaning properties, the content of the surfactant in the rinse composition (content based on weight) can be, for example, 1.0×10 ⁻⁵ wt % or more. From the viewpoint of reducing the number of defects, the content is preferably 2.0×10 ⁻⁵ wt % or more, more preferably 5.0×10 ⁻⁵ wt % or more, even more preferably 1.0×10 ⁻⁴ wt % or more, for example 2.0×10 ⁻⁴ wt % or more. From the viewpoint of cleaning efficiency, the content is preferably 0.02 wt % or less, more preferably 0.01 wt % or less, and even more preferably 0.005 wt % or less (for example 0.002 wt % or less). Alternatively, from the viewpoint of simplifying the composition, the rinse composition disclosed herein can be preferably implemented in an embodiment that does not substantially contain a surfactant.

<Water>
The rinse composition disclosed herein typically contains water. As the water, ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, etc. can be preferably used. In order to avoid as much as possible the inhibition of the action of other components contained in the rinse composition, it is preferable that the water used has a total transition metal ion content of, for example, 100 ppb or less. For example, the purity of the water can be increased by removing impurity ions with an ion exchange resin, removing foreign matter with a filter, distillation, or other operations.

<Other ingredients>
In addition, the rinse composition disclosed herein may further contain, as necessary, known additives such as a chelating agent, an organic acid, an organic acid salt, an inorganic acid, an inorganic acid salt, a preservative, or an antifungal agent, as long as the effects of the present invention are not significantly impaired.

The rinse composition disclosed herein is preferably substantially free of an oxidizing agent. Specific examples of the oxidizing agent include hydrogen peroxide (H ₂ O ₂ ), sodium persulfate, ammonium persulfate, and sodium dichloroisocyanurate. The rinse composition being substantially free of an oxidizing agent means that the oxidizing agent is not intentionally contained at least. Therefore, a rinse composition that inevitably contains a small amount of oxidizing agent (for example, the molar concentration of the oxidizing agent in the rinse composition is 0.0005 mol/L or less, preferably 0.0001 mol/L or less, more preferably 0.00001 mol/L or less, particularly preferably 0.000001 mol/L or less) due to raw materials, manufacturing method, etc., can be included in the concept of a rinse composition that does not substantially contain an oxidizing agent as described herein.

The rinsing composition disclosed herein does not contain abrasive grains. In addition, when the rinsing composition does not contain abrasive grains, it means that the rinsing composition does not contain abrasive grains, at least intentionally. When the rinsing composition that does not contain abrasive grains is used for rinsing, the number of abrasive grains remaining after rinsing can be reduced.

<pH>
The pH of the rinsing composition disclosed herein is typically 8.0 or more, preferably 8.5 or more, more preferably 9.0 or more. From the viewpoint of compatibility with the polishing composition used immediately before the rinsing step, the pH of the rinsing composition is usually appropriate to be 12.0 or less, preferably 11.0 or less, more preferably 10.8 or less, and even more preferably 10.5 or less.

The pH can be determined by using a pH meter (for example, a glass electrode type hydrogen ion concentration indicator (model number F-23) manufactured by Horiba, Ltd.) and performing three-point calibration using standard buffer solutions (phthalate pH buffer solution, pH: 4.01 (25°C), neutral phosphate pH buffer solution, pH: 6.86 (25°C), carbonate pH buffer solution, pH: 10.01 (25°C)), then placing the glass electrode in the composition to be measured and measuring the value after it has stabilized for at least two minutes.

<Rinse solution>
The rinse composition disclosed herein is typically supplied to the surface of the polished object after polishing in the form of a rinse liquid containing the rinse composition, and is used to rinse the polished object. The rinse liquid may be prepared, for example, by diluting any of the rinse compositions disclosed herein (typically diluting with water). Alternatively, the rinse composition may be used as a rinse liquid as it is. That is, the concept of the rinse composition in the technology disclosed herein includes both a rinse liquid that is supplied to the polished object after polishing and used to rinse the polished object, and a concentrated liquid (undiluted rinse liquid) that is diluted and used as a rinse liquid.

<Concentrate>
The rinsing composition disclosed herein may be in a concentrated form (i.e., in the form of a concentrated rinsing liquid) before being supplied to a polished object after polishing. A rinsing composition in such a concentrated form is advantageous from the viewpoints of convenience and cost reduction during production, distribution, storage, etc. The concentration ratio is not particularly limited, and can be, for example, about 2 to 100 times in volume terms, and is usually about 5 to 50 times (e.g., about 10 to 40 times).
Such a concentrated solution can be used in such a manner that it is diluted at a desired time to prepare a rinse solution, and the rinse solution is supplied to the polishing object after polishing. The dilution can be performed, for example, by adding water to the concentrated solution and mixing it.

<Preparation of Rinse Composition>
The rinse composition used in the technology disclosed herein may be a one-component type or a multi-component type such as a two-component type. For example, the rinse composition may be configured to prepare a polishing liquid by mixing a part A containing at least a water-soluble polymer A and a part B containing at least a part of the remaining components, and mixing and diluting them at an appropriate timing as necessary.

The method for preparing the rinse composition is not particularly limited. For example, the components constituting the rinse composition may be mixed using a well-known mixing device such as a blade stirrer, ultrasonic disperser, or homomixer. The manner in which these components are mixed is not particularly limited, and for example, all the components may be mixed at once, or may be mixed in an appropriately set order.

<Applications>
The rinsing composition disclosed herein can be applied to the rinsing of the polished object having various materials and shapes after polishing.The material of the polished object can be, for example, metal or semimetal such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium, stainless steel, or their alloys; glassy material such as quartz glass, aluminosilicate glass, glassy carbon; ceramic material such as alumina, silica, sapphire, silicon nitride, tantalum nitride, titanium carbide; compound semiconductor substrate material such as silicon carbide, gallium nitride, gallium arsenide; resin material such as polyimide resin; etc.The polished object can be made of a plurality of materials among these.

The rinsing composition disclosed herein can be particularly preferably used for rinsing after polishing of a surface made of silicon (typically, polishing of a silicon wafer). A typical example of the silicon wafer referred to here is a silicon single crystal wafer, for example, a silicon single crystal wafer obtained by slicing a silicon single crystal ingot.

The rinsing composition disclosed herein can be preferably used for rinsing an object to be polished (e.g., a silicon wafer) after a polishing process. Before the polishing process, the object to be polished may be subjected to a general treatment that can be applied to the object to be polished in a process upstream of the polishing process, such as lapping or etching.

The rinsing composition disclosed herein is effective for use in rinsing after polishing of a finishing step or the polishing step immediately preceding the finishing step of an object to be polished (e.g., a silicon wafer), and is particularly preferably used for rinsing after a finishing polishing step. Here, the finishing polishing step refers to the final polishing step in the manufacturing process of the object (i.e., a step after which no further polishing is performed).

<Rinsing method>
The rinsing composition disclosed herein can be used to rinse an object to be polished after polishing, for example, in an embodiment including the following operations: Hereinafter, a preferred embodiment of a method for rinsing an object to be polished (e.g., a silicon wafer) after polishing with the rinsing composition disclosed herein will be described.
That is, a rinse liquid containing any of the rinse compositions disclosed herein is prepared. The preparation of the rinse liquid may include adjusting the concentration (e.g., diluting) or adjusting the pH of the rinse composition to prepare the rinse liquid. Alternatively, the rinse composition may be used as it is as the rinse liquid.

The rinsing liquid is then supplied to the polished object after polishing, and it is rinsed in the usual manner. For example, when rinsing a silicon wafer after a finish polishing process, typically, the silicon wafer that has undergone the finish polishing process is attached to a general polishing device, or is left attached to the polishing device that performed the finish polishing process, and the rinsing liquid is supplied to the surface of the silicon wafer to be polished through the pad of the polishing device. Typically, while the rinsing liquid is continuously supplied, the pad is pressed against the surface of the silicon wafer to be polished, and the two are moved relative to each other (e.g., rotated). Rinsing of the polished object is completed through this rinsing process.

The pads used in the above rinsing step are not particularly limited. For example, pads of a polyurethane foam type, a nonwoven fabric type, a suede type, etc. can be used. Each pad may or may not contain abrasive grains. Usually, pads that do not contain abrasive grains are preferably used.

Rinsing using the rinsing composition disclosed herein can be performed immediately after the polishing process, on the object to be polished while it is still attached to the polishing device used in the polishing process, on the same platen as the polishing platen. Alternatively, after the polishing process, the object to be polished may be removed from the polishing device and transferred to a different platen for rinsing. From the standpoint of work efficiency, etc., it is preferable to perform rinsing on the platen of the polishing device used in the polishing process.

The temperature at which the rinse composition disclosed herein is used is not particularly limited, but is preferably 5 to 60°C.

The polishing object rinsed with the rinsing composition disclosed herein is typically cleaned. Cleaning can be performed using an appropriate cleaning liquid. The cleaning liquid used is not particularly limited, and for example, SC-1 cleaning liquid (a mixture of ammonium hydroxide (NH ₄ OH), hydrogen peroxide (H ₂ O ₂ ), and water (H ₂ O)) and SC-2 cleaning liquid (a mixture of HCl, H ₂ O ₂ , and H ₂ O) that are common in the field of semiconductors and the like can be used. The temperature of the cleaning liquid can be, for example, in the range of room temperature (typically about 15° C. to 25° C.) or higher, up to about 90° C. From the viewpoint of improving the cleaning effect, a cleaning liquid of about 50° C. to 85° C. can be preferably used.

Several examples of the present invention are described below, but it is not intended that the present invention be limited to those shown in these examples. In the following description, "parts" and "%" are by weight unless otherwise specified.

<Preparation of Rinse Composition>
Example 1
A water-soluble polymer, a basic compound, a surfactant, and deionized water were mixed to prepare a rinse composition according to this example. As the water-soluble polymer, polyacryloylmorpholine (hereinafter referred to as "PACMO") having a desorption parameter of 174 and a weight average molecular weight of about 350,000, and polyvinyl alcohol (PVA) having a desorption parameter of 117, a weight average molecular weight of about 100,000, and a saponification degree of 97.5% or more were used. The content of PACMO was 0.004%. The content of PVA was 0.005%. Ammonia was used as the basic compound, and its content was 0.005%. As the surfactant, polyoxyethylene decyl ether (hereinafter referred to as "C10PEO5") having an ethylene oxide addition mole number of 5 was used, and its content was 0.0008%.

Example 2
A rinse composition according to this example was prepared in the same manner as in Example 1, except that the content of PACMO in the composition of Example 1 was changed to 0.002%.

(Comparative Example 1)
The rinse composition of this example was prepared in the same manner as in Example 1, except that hydroxyethyl cellulose (hereinafter referred to as "HEC") having a desorption parameter of 140 and a weight average molecular weight of approximately 250,000 was used as the water-soluble polymer and its content was 0.013%.

(Comparative Example 2)
In this example, no rinsing with a rinsing composition was performed.

<Polishing, rinsing, and cleaning of silicon wafers>
As the object to be polished, a commercially available silicon single crystal wafer having a diameter of 300 mm (conductivity type: P type, crystal orientation: <100>, COP-free) that had been lapped and etched was pre-polished under the following polishing condition 1. The pre-polishing was performed using a polishing solution containing 0.95% abrasive grains (colloidal silica with an average primary particle size of 35 nm) and 0.065% potassium hydroxide in deionized water.

[Polishing condition 1]
Polishing device: Single-wafer polishing device manufactured by Okamoto Machine Tools Works, Ltd. Model "PNX-332B"
Polishing load: 20 kPa
Rotation speed of the platen: 20 rpm
Head (carrier) rotation speed: 20 rpm
Polishing pad: Fujibo Ehime Co., Ltd. Product name "POLYPAS27NX"
Supply rate of preliminary polishing liquid: 1 L/min
Temperature of preliminary polishing solution: 20°C
Temperature of cooling water for surface plate: 20°C
Polishing time: 2 minutes

The silicon wafer after the above preliminary polishing was finish-polished under the following polishing condition 2. The polishing liquid used was a polishing composition prepared by mixing abrasive grains, a water-soluble polymer, a basic compound, a surfactant, and deionized water. Colloidal silica (average primary particle size: 25 nm) was used as the abrasive grains, and its content was set to 0.18%. HEC with a weight-average molecular weight of about 250,000 and N-vinylpyrrolidone homopolymer (hereinafter referred to as "PVP") with a weight-average molecular weight of about 45,000 were used as the water-soluble polymers. The HEC content was set to 0.004%. The PVP content was set to 0.003%. Ammonia was used as the basic compound, and its content was set to 0.005%. C10PEO5 was used as the surfactant, and its content was set to 0.0002%.

[Polishing condition 2]
Polishing device: Single-wafer polishing device manufactured by Okamoto Machine Tools Works, Ltd. Model "PNX-332B"
Polishing load: 15 kPa
Rotation speed of the platen: 30 rpm
Head (carrier) rotation speed: 30 rpm
Polishing pad: Fujibo Ehime Co., Ltd. Product name "POLYPAS27NX"
Polishing liquid supply rate: 2 L/min
Polishing solution temperature: 20°C
Temperature of cooling water for surface plate: 20°C
Polishing time: 2.5 minutes

The rinsing compositions prepared above for each example were used as rinsing liquids to rinse the silicon wafers after the above finish polishing under the following rinsing conditions.

[Rinse conditions]
Equipment: Single-wafer polishing machine manufactured by Okamoto Machine Tools Works, Ltd. Model "PNX-332B"
Load: 5 kPa
Rotation speed of the platen: 30 rpm
Head (carrier) rotation speed: 30 rpm
Pad: Fujibo Ehime Co., Ltd. Product name "POLYPAS27NX"
Rinse liquid supply rate: 1 L/min
Rinse solution temperature: 20°C
Temperature of cooling water for surface plate: 20°C
Rinse time: 10 seconds

The rinsed silicon wafer was removed from the apparatus and washed with a cleaning solution of NH ₄ OH (29%): H ₂ O ₂ (31%): deionized water (DIW) = 2: 5.3: 48 (volume ratio) (SC-1 washing). Specifically, a washing tank equipped with an ultrasonic oscillator was prepared, and the above-mentioned cleaning solution was placed in the washing tank and maintained at 60°C. The polished silicon wafer was immersed in the washing tank for 6 minutes, and then rinsed with ultrapure water. This process was repeated twice, and the silicon wafer was then dried.

<Measurement of number of defects>
The surface of the silicon wafer after cleaning was inspected for surface defects using a wafer inspection device manufactured by KLA Tencor, product name "Surfscan SP2 ^XP ". Each of the detected defects was analyzed using a defect review SEM (scanning electron microscope) manufactured by Hitachi High-Technologies Corporation, product name "Review-SEM RS6000", and the number of defects was counted as the number of abrasive grain residues and the number of PIDs. The number of abrasive grain residues and the number of PIDs of each example in which rinsing was performed were calculated as a relative ratio, with the number of abrasive grain residues and the number of PIDs of Comparative Example 1 in which rinsing was not performed being set to 100, respectively. The results are shown in Table 1.

As shown in Table 1, in Examples 1 and 2, in which the object to be polished was rinsed using a rinsing composition containing PACMO, which has a desorption parameter of 150 or more, and unmodified PVA, which has a desorption parameter of less than 150, as the water-soluble polymer, a clear reduction in the number of defects (i.e., the number of abrasive residues and the number of PIDs) on the surface of the object to be polished was confirmed compared to Comparative Example 1, in which rinsing was not performed after polishing. On the other hand, in Comparative Example 2, in which the object to be polished was rinsed using a rinsing composition containing only HEC, which has a desorption parameter of less than 150, as the water-soluble polymer, the number of abrasive residues on the surface of the object to be polished was reduced compared to Comparative Example 1, in which rinsing was not performed after polishing, but no reduction in PIDs was observed and instead increased.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above.

Claims (6)

A rinse composition comprising a water-soluble polymer and no abrasive grains,
The water-soluble polymer may be a polymer having the following formula (I):
W1/W0×100 (I)
(W0 in the formula (I) is the static contact angle of deionized water of a wafer before SC-1 cleaning treatment, which is obtained by applying an aqueous solution of a water-soluble polymer to be evaluated to the surface of a silicon wafer and then rinsing with water, and W1 in the formula (I) is the static contact angle of deionized water of a wafer after SC-1 treatment, which is obtained by performing a cleaning treatment for 10 seconds on the wafer before SC-1 cleaning treatment with a room temperature SC-1 cleaning solution containing 29% ammonia water, 31% hydrogen peroxide water, and water in a volume ratio of 0.5:0.5:8.)
The water-soluble polymer A has a desorption parameter of 150 or more,
The water-soluble polymer further includes a water-soluble polymer B having an elimination parameter represented by formula (I) of less than 150,
The weight average molecular weight of the water-soluble polymer B is 2×10 ⁴ or more ,
The rinse composition further comprises a surfactant . The rinse composition according to claim 1, wherein the water-soluble polymer A includes a nitrogen atom-containing polymer. The rinse composition according to claim 1 or 2, further comprising a basic compound. A rinsing method for rinsing an object to be polished that has been polished in a polishing step using a polishing composition containing abrasive grains, comprising:
A rinsing method comprising: a rinsing step of supplying a rinsing liquid containing the rinsing composition according to claim 1 to the object to be polished to rinse the object. The rinsing method according to claim 4, wherein in the rinsing step, the rinsing liquid is supplied to the object to be polished on a platen of a polishing device used in the polishing step. The rinsing method according to claim 4 or 5, wherein the object to be polished is a silicon wafer.