Post-chemical mechanical polishing and cleaning composition, post-chemical mechanical polishing and cleaning method, and method for manufacturing a semiconductor substrate

Abstract

The present invention provides a means for effectively removing residue remaining on the surface of a polished object containing silicon-based material. [Solution] A post-chemical mechanical polishing and cleaning composition comprising an anionic polymer containing a sulfonic acid group and a nitrogen-containing nonionic polymer with a weight-average molecular weight of 2,000 or more and 20,000 or less.

Description

[Technical Field]

[0001] The present invention relates to a post-chemical mechanical polishing and cleaning composition, a post-chemical mechanical polishing and cleaning treatment method, and a method for manufacturing a semiconductor substrate. [Background technology]

[0002] In recent years, with the increasing use of multilayer wiring on semiconductor substrate surfaces, chemical mechanical polishing (CMP) technology, which physically polishes and flattens semiconductor substrates, has been utilized during device manufacturing. CMP is a method of flattening the surface of a workpiece (object to be polished), such as a semiconductor substrate, using a polishing composition (slurry) containing abrasive particles such as silica, alumina, and ceria, as well as corrosion inhibitors and surfactants. The workpieces to be polished include wiring and plugs made of silicon-containing materials such as silicon, polysilicon, silicon oxide, and silicon nitride, or metals.

[0003] After the CMP (Chemical Polishing) process, a large amount of impurities (also referred to as foreign matter or residue) remain on the surface of the semiconductor substrate. These impurities include abrasive particles, metals, corrosion inhibitors, surfactants and other organic substances derived from the polishing composition used in CMP, silicon-containing materials that were polished, silicon-containing materials and metals generated by polishing metal wiring and plugs, and organic substances such as pad debris generated from various pads.

[0004] If the semiconductor substrate surface is contaminated with these impurities, it can adversely affect the electrical properties of the semiconductor and reduce the reliability of the device. Therefore, it is desirable to introduce a cleaning process after the CMP process to remove these impurities from the semiconductor substrate surface.

[0005] As an example of such a cleaning composition, Patent Document 1 discloses a rinsing composition for silicon wafers containing a water-soluble polymer that satisfies specific conditions, which can remove foreign matter from the silicon wafer after polishing and reduce defects in the silicon wafer after polishing. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-167237 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the technology described in Patent Document 1 had the problem that it could not adequately remove foreign matter (residue) when cleaning polished objects containing silicon-based materials.

[0008] Therefore, the present invention aims to provide a means that can sufficiently remove residue remaining on the surface of a polished object containing a silicon-containing material. [Means for solving the problem]

[0009] In view of the above problems, the inventors conducted thorough research. As a result, they found that the above problems could be solved by a post-chemical mechanical polishing and cleaning composition comprising an anionic polymer containing a sulfonic acid group and a nitrogen-containing nonionic polymer with a weight-average molecular weight of 2,000 to 20,000, and thus completed the present invention. [Effects of the Invention]

[0010] The present invention provides a means for sufficiently removing residue remaining on the surface of a polished object containing a silicon-containing material. [Modes for carrying out the invention]

[0011] One embodiment of the present invention is a post-chemical mechanical polishing and cleaning composition comprising an anionic polymer containing a sulfonic acid group and a nitrogen-containing nonionic polymer having a weight-average molecular weight of 2,000 or more and 20,000 or less.

[0012] In this specification, a post-chemical mechanical polishing and cleaning composition having the above configuration will also be referred to as "post-chemical mechanical polishing and cleaning composition according to this embodiment," "post-CMP cleaning composition," or "post-CMP cleaning composition according to this embodiment."

[0013] According to the post-chemical mechanical polishing and cleaning composition (post-CMP cleaning composition) of this embodiment, residues remaining on the surface of polished objects, particularly silicon-containing materials such as silicon nitride, silicon oxide, and polysilicon, can be sufficiently removed (e.g., abrasive residues (especially silicon compounds), organic residues).

[0014] In this specification, "polished object" refers to an object that has been polished with an abrasive composition. In the present invention, the polished object includes a silicon-containing material. A polished object containing silicon nitride means that the polished object has a film (layer) containing silicon nitride, a polished object containing silicon oxide means that the polished object has a film (layer) containing silicon oxide, and a polished object containing polysilicon means that the polished object has a film (layer) containing polysilicon. In other words, the polished object according to this embodiment has at least one silicon-containing material selected from the group consisting of silicon nitride, silicon oxide, and polysilicon. Hereinafter, "polished object containing silicon-containing material" may be simply referred to as "polished object".

[0015] By configuring the post-CMP cleaning composition according to this embodiment as described above, the nitrogen-containing nonionic polymer and the anionic polymer containing sulfonic acid groups become more effectively adsorbed onto the polished object. This is thought to allow for more efficient removal of residue from the surface of the polished object while preventing the re-adhesion of residue (e.g., abrasive residue and / or contaminants such as organic residue) to the surface of the polished object. The inventors speculate that the above configuration allows for the removal of residue from the surface of the polished object as follows.

[0016] For example, sulfonic acid groups in anionic polymers containing sulfonic acid groups can still attract hydrogen ions (H) even in solutions with a low pH (e.g., solutions with a pH of 2-4). + ) emits ionized (R-SO3) - ) . As a result, the anionic polymer containing sulfonic acid groups can adsorb to the surface of the polished object and the abrasive residue, and their zeta potentials can both be controlled to be negative (negative). This creates an electrostatic repulsion between the polished object and the abrasive residue, allowing the abrasive residue to efficiently detach from the polished object and preventing it from reattaching to the polished object. The anionic polymer containing sulfonic acid groups is particularly easily adsorbed by films containing silicon nitride, and the above effect can be suitably exhibited in films containing silicon nitride.

[0017] Furthermore, nitrogen-containing nonionic polymers exhibit good compatibility with hydrophobic substances through intermolecular and hydrophobic interactions. As a result, they adsorb onto the surface of hydrophobic polished objects (e.g., films containing silicon dioxide and / or polysilicon), and act to efficiently detach organic residues from the polished objects.

[0018] However, the inventors discovered a trade-off: while nitrogen-containing nonionic polymers can reduce organic residue, they tend to leave more abrasive residue. Therefore, the inventors focused on the fact that the abrasive residue reduction effect of anionic polymers containing sulfonic acid groups is inhibited by the inclusion of nitrogen-containing nonionic polymers.

[0019] Therefore, the present inventor has studied means for satisfying both of the above requirements that are in a trade-off relationship, that is, means capable of reducing both abrasive grain residues and organic residues. As a result, it has been found that the value of the weight average molecular weight of the nitrogen-containing nonionic polymer affects the value of the zeta potential of the polished object to be polished (for example, a film containing silicon nitride) that is negatively charged by the anionic polymer containing a sulfonic acid group. The present inventor speculates that regarding this phenomenon, the nitrogen-containing nonionic polymer adsorbs to the anionic polymer containing a sulfonic acid group, affects the negative charge of the anionic polymer containing a sulfonic acid group, and as a result, may be affecting the negative charging of the polished object to be polished. And it has been found that the smaller the weight average molecular weight of the nitrogen-containing nonionic polymer, the less it inhibits the negative charging of the polished object to be polished by the anionic polymer containing a sulfonic acid group. However, it has also been found that the smaller the weight average molecular weight of the nitrogen-containing nonionic polymer, the lower the effect of adsorbing the nitrogen-containing nonionic polymer to hydrophobic substances (for example, hydrophobic polished objects to be polished), and the lower the reduction effect of organic residues. As a result of such intensive studies, the present inventor has found that if the weight average molecular weight of the nitrogen-containing nonionic polymer is 2,000 or more and 20,000 or less, the reduction effect of abrasive grain residues can be maintained, and the reduction effect of organic residues by the nitrogen-containing nonionic polymer can also be maintained.

[0020] Furthermore, with the above configuration, each component adsorbed on the surface of the polished object to be polished (nitrogen-containing nonionic polymer and anionic polymer containing a sulfonic acid group) can also be easily desorbed from the surface of the polished object to be polished, and each component adsorbed on the surface of the polished object to be polished itself hardly becomes a residue or can be in a state where there is no residue. From the above, it is considered that the post-CMP cleaning composition of the present invention can sufficiently remove residues.

[0021] Note that the above mechanism is based on speculation, and the present invention is not limited to the above mechanism at all.

[0022] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to only the following embodiments and can be variously modified within the scope of the claims. The embodiments described in this specification can be combined arbitrarily to form other embodiments. In this specification, unless otherwise specified, measurements such as operations and physical properties are performed under the conditions of room temperature (20°C or higher and 25°C or lower) / relative humidity of 40%RH or higher and 50%RH or lower.

[0023] <Residue> In this specification, the residue refers to foreign matter adhering to the surface of the polished object to be polished. Examples of the residue are not particularly limited, and include, for example, organic residues described later, particle residues derived from abrasive grains contained in the polishing composition, residues composed of components other than particle residues and organic residues, and other residues such as mixtures of particle residues and organic residues.

[0024] In this specification, the organic residue refers to a component composed of an organic substance such as an organic low molecular compound or a polymer compound, or an organic salt among the foreign matters adhering to the surface of the polished object to be polished (surface treatment object).

[0025] The organic residues adhering to the polished object to be polished include, for example, pad debris generated from the pad used in the polishing process or the rinse polishing process described later, or components derived from additives contained in the polishing composition used in the polishing process or the post-CMP cleaning composition used in the rinse polishing process.

[0026] Since the organic residue and other foreign matters are significantly different in color and shape, the determination of whether the foreign matter is an organic residue can be visually performed by SEM observation. Further, the determination of whether the foreign matter is an organic residue can be determined by elemental analysis using an energy dispersive X-ray analyzer (EDX) as necessary. The number of organic residues can be measured using a wafer defect inspection device and SEM or EDX elemental analysis.

[0027] <Polished object to be polished> In this specification, "polished object" refers to an object that has been polished in the polishing process. The polishing process is the CMP process.

[0028] The polished object to be polished according to this embodiment includes at least one silicon-containing material selected from the group consisting of silicon nitride (Si3N4), silicon oxide (SiO2), and polysilicon (polycrystalline silicon). In one embodiment, the polished object to be polished according to this embodiment includes silicon nitride (Si3N4), silicon oxide (SiO2), and polysilicon (polycrystalline silicon). In another embodiment, the polished object to be polished according to this embodiment includes at least one selected from the group consisting of silicon nitride (Si3N4) and polysilicon (polycrystalline silicon).

[0029] The material included in the object to be polished according to this embodiment is not particularly limited as long as it includes at least one silicon-containing material selected from the group consisting of silicon nitride (Si3N4), silicon oxide (SiO2), and polysilicon (polycrystalline silicon). For example, it may further include carbon-containing silicon such as silicon carbonitride (SiCN), amorphous silicon, silicon materials doped with impurities, elemental metals, alloys, metal nitrides, compound semiconductors such as SiGe, etc.

[0030] Examples of silicon dioxide-containing films include, for example, TEOS (Tetraethyl Orthosilicate) type silicon dioxide films (hereinafter also simply referred to as "TEOS films") produced using tetraethyl orthosilicate as a precursor, HDP (High Density Plasma) films, USG (Undoped Silicate Glass) films, PSG (Phosphorus Silicate Glass) films, BPSG (Boron-Phospho Silicate Glass) films, and RTO (Rapid Thermal Oxidation) films. The silicon dioxide-containing films contained in the polished object may be a single type or a combination of two or more types.

[0031] The polished object to be polished is preferably a polished semiconductor substrate, specifically a semiconductor substrate after the CMP (Chemical Polishing) process. This is because residue can cause defects in semiconductor devices, and therefore, when the polished object to be polished is a polished semiconductor substrate, the cleaning process for the semiconductor substrate must be able to remove as much residue as possible.

[0032] Furthermore, a post-CMP cleaning composition according to one embodiment of the present invention can reduce surface residue even on polished objects that contain both hydrophilic and hydrophobic materials. Here, a hydrophilic material refers to a material with a contact angle with water of less than 50°, and a hydrophobic material refers to a material with a contact angle with water of 50° or more. The contact angle with water is a value measured using a DropMaster (DMo-501) contact angle meter manufactured by Kyowa Interface Science Co., Ltd.

[0033] Specific examples of hydrophilic materials include, for example, silicon oxide, silicon nitride, silicon oxynitride, tungsten, titanium nitride, tantalum nitride, and boron-containing silicon. These hydrophilic materials may be used individually or in combination of two or more. According to one preferred embodiment of the present invention, the hydrophilic material is silicon nitride. According to one preferred embodiment of the present invention, the hydrophilic materials are silicon nitride and silicon oxide. Specific examples of hydrophobic materials include, for example, polysilicon (polycrystalline silicon), monocrystalline silicon, amorphous silicon, and carbon-containing silicon. These hydrophobic materials may be used individually or in combination of two or more. According to one preferred embodiment of the present invention, the hydrophobic material is polysilicon (polycrystalline silicon).

[0034] In other words, according to a preferred embodiment of the present invention, the hydrophilic material is silicon nitride, and the hydrophobic material is polysilicon (polycrystalline silicon). Alternatively, according to a preferred embodiment of the present invention, the hydrophilic material is silicon nitride and silicon oxide, and the hydrophobic material is polysilicon (polycrystalline silicon).

[0035] <Post-chemical mechanical polishing and cleaning composition (post-CMP cleaning composition)> The post-chemical mechanical polishing and cleaning composition (post-CMP cleaning composition) according to this embodiment comprises a nitrogen-containing nonionic polymer and an anionic polymer containing a sulfonic acid group. Herein, "polymer" means a compound with a weight-average molecular weight (Mw) of 1,000 or more. Furthermore, in this specification, "nonionic polymer" means a polymer that does not have anionic groups such as carboxylic acid groups, sulfonic acid groups, or phosphate groups, or cationic groups such as amino groups or quaternary ammonium groups in its molecule. "Anionic polymer" means a polymer that has anionic groups such as carboxylic acid groups, sulfonic acid groups, or phosphate groups in its molecule.Each polymer will be described below.

[0036] [Nitrogen-containing nonionic polymer] The nitrogen-containing nonionic polymer contained in the post-CMP cleaning composition according to this embodiment refers to a nonionic polymer that contains a nitrogen atom in its molecule. The nitrogen-containing nonionic polymer contained in the post-CMP cleaning composition according to this embodiment has a weight-average molecular weight of 2,000 or more and 20,000 or less. If the weight-average molecular weight of the nitrogen-containing nonionic polymer is less than 2,000, the adsorption effect of the nitrogen-containing nonionic polymer to hydrophobic substances (e.g., hydrophobic polished abrasive objects) decreases, and the effect of reducing organic residue decreases. If the weight-average molecular weight of the nitrogen-containing nonionic polymer exceeds 20,000, the nitrogen-containing nonionic polymer inhibits the negative abrasiveization of polished abrasive objects by anionic polymers containing sulfonic acid groups, and the effect of reducing abrasive residue decreases.

[0037] The weight-average molecular weight of the nitrogen-containing nonionic polymer is preferably 3,000 or more, more preferably 5,000 or more, even more preferably 7,000 or more, even more preferably 8,000 or more, particularly preferably 8,500 or more, and most preferably 9,000 or more. Furthermore, the weight-average molecular weight of the nitrogen-containing nonionic polymer is preferably 18,000 or less, more preferably 15,000 or less, even more preferably 14,000 or less, even more preferably 13,000 or less, particularly preferably 12,000 or less, and most preferably 11,000 or less. Specifically, the weight-average molecular weight of the nitrogen-containing nonionic polymer is preferably 3,000 to 18,000, more preferably 5,000 to 15,000, even more preferably 7,000 to 14,000, even more preferably 8,000 to 13,000, particularly preferably 8,500 to 12,000, and most preferably 9,000 to 11,000. When the weight-average molecular weight of the nitrogen-containing nonionic polymer is within the above range, residue on the surface of the polished object after treatment with the post-CMP cleaning composition can be removed more efficiently, and the intended effects of the present invention are more fully realized.

[0038] The nitrogen-containing nonionic polymer can be any nonionic polymer having a nitrogen atom, such as polyamines, polyvinylpyrrolidone, polyacrylamide, poly-N-vinylacetamide, polydimethylacrylamide, polyacryloylmorpholine, poly-N-vinylcaprolactam, poly-N-isopropylacrylamide, and oxazoline group-containing polymers. Not only polymers having the main chain structure described above, but also graft copolymers having nonionic polymer structures in their side chains can be suitably used as nitrogen-containing nonionic polymers. The nitrogen-containing nonionic polymer may be a polymer having identical (homopolymer) or different (copolymer) repeating structural units, and when the nitrogen-containing nonionic polymer is a copolymer, the copolymer may take the form of a block copolymer, random copolymer, graft copolymer, or alternating copolymer.

[0039] The nitrogen-containing nonionic polymer is preferably a polymer having an amide bond or an oxazoline group, more preferably a polymer having an amide bond or an oxazoline group in the structure of its side chain, and even more preferably at least one selected from the group consisting of polyvinylpyrrolidone, poly-N-vinylacetamide, polydimethylacrylamide, polyvinylcaprolactam, N-isopropylacrylamide, and oxazoline group-containing polymers. The nitrogen-containing nonionic polymer may be used alone or in combination of two or more types. Furthermore, the nitrogen-containing nonionic polymer may be a commercially available product or a synthesized product.

[0040] The nitrogen-containing nonionic polymer content in the post-CMP cleaning composition is preferably more than 1 ppm by mass, more preferably 5 ppm or more, even more preferably 10 ppm or more, even more preferably 50 ppm or more, particularly preferably 100 ppm or more, and most preferably 150 ppm or more, based on the total mass of the post-CMP cleaning composition. The nitrogen-containing nonionic polymer content in the post-CMP cleaning composition is preferably 5% by mass (50,000 ppm by mass) or less, more preferably 3% by mass (30,000 ppm by mass) or less, even more preferably 2% by mass (20,000 ppm by mass) or less, even more preferably 1.5% by mass (15,000 ppm by mass) or less, particularly preferably 1% by mass (10,000 ppm by mass) or less, and most preferably 0.5% by mass (5,000 ppm by mass) or less, based on the total mass of the post-CMP cleaning composition. In other words, the content of nitrogen-containing nonionic polymer is preferably more than 1 ppm by mass and 5% by mass or less, more preferably 5 ppm by mass and 3% by mass or less, even more preferably 10 ppm by mass and 2% by mass or less, even more preferably 50 ppm by mass and 1.5% by mass or less, particularly preferably 100 ppm by mass and 1% by mass or less, and most preferably 150 ppm by mass and 0.5% by mass or less. When the content of nitrogen-containing nonionic polymer is within the above range, residue on the surface of the polished object after treatment with the post-CMP cleaning composition can be removed more efficiently, and the intended effects of the present invention are more fully realized.

[0041] According to one embodiment, in the post-CMP cleaning composition, the content of nitrogen-containing nonionic polymer is 10 ppm by mass or more and 1% by mass or less, based on the total mass of the post-CMP cleaning composition.

[0042] If a post-CMP cleaning composition contains two or more nitrogen-containing nonionic polymers, the content of the nitrogen-containing nonionic polymers shall be the sum of these amounts.

[0043] [Anionic polymer containing sulfonic acid groups] The anionic polymer containing sulfonic acid groups contained in the post-CMP cleaning composition according to this embodiment acts as a dispersant in the post-CMP cleaning composition. By including the anionic polymer containing sulfonic acid groups in the post-CMP cleaning composition, the zeta potential of the surface of the polished object (e.g., a polished object containing silicon nitride) and the zeta potential of defect sources such as abrasive grains and organic residues are both controlled to be negative, forming an electrostatic repulsion layer, and as a result, the number of defects in the polished object can be reduced.

[0044] The weight-average molecular weight of the anionic polymer containing sulfonic acid groups is preferably 1,500 or more, more preferably 3,000 or more, even more preferably 4,000 or more, even more preferably 5,000 or more, particularly preferably 6,000 or more, particularly more preferably 7,000 or more, and most preferably 8,000 or more. Furthermore, the weight-average molecular weight of the anionic polymer containing sulfonic acid groups is preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 100,000 or less, even more preferably 50,000 or less, particularly preferably 25,000 or less, particularly more preferably 20,000 or less, and most preferably 15,000 or less. Specifically, the weight-average molecular weight of the anionic polymer containing sulfonic acid groups is preferably 1,500 to 1,000,000, more preferably 3,000 to 500,000, even more preferably 4,000 to 100,000, even more preferably 5,000 to 50,000, particularly preferably 6,000 to 25,000, particularly more preferably 7,000 to 20,000, and most preferably 8,000 to 15,000. When the weight-average molecular weight of the anionic polymer containing sulfonic acid groups is within the above range, residue on the surface of the polished object after treatment with the post-CMP cleaning composition can be removed more efficiently, and the intended effects of the present invention are more fully realized.

[0045] Anionic polymers containing sulfonic acid groups can be any polymer that has sulfonic acid groups. Specific examples include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polymethallyl sulfonic acid, poly(2-acrylamide-2-methylpropanesulfonic acid), polyisoprene sulfonic acid, (meth)acrylic acid-isoprene sulfonic acid copolymer, (meth)acrylic acid-[2-(meth)acrylamide-2-methylpropanesulfonic acid] copolymer, and (meth)acrylic acid-isoprene sulfonic acid-[2-(meth)acrylamide-2-methylpropanesulfonic acid] copolymer. These anionic polymers containing sulfonic acid groups may also exist in the form of neutralized salts.

[0046] Furthermore, as anionic polymers containing sulfonic acid groups, not only those having the main chain structure described above, but also graft copolymers having anionic polymer structures containing sulfonic acid groups in their side chains can be suitably used. The above anionic polymers containing sulfonic acid groups may be polymers having identical (homopolymer) or different (copolymer) repeating structural units, and when the anionic polymer containing sulfonic acid groups is a copolymer, the form of the copolymer may be a block copolymer, a random copolymer, a graft copolymer, or an alternating copolymer. In addition, the repeating structure of the copolymer may consist of repeating structures having sulfonic acid groups and repeating structures not having sulfonic acid groups, or it may consist only of repeating structures having two or more types of sulfonic acid groups.

[0047] Furthermore, the anionic group in the anionic polymer containing a sulfonic acid group may consist solely of a sulfonic acid group, or it may contain one or more anionic groups other than a sulfonic acid group.

[0048] Anionic polymers containing sulfonic acid groups may be used individually or in combination of two or more. In post-CMP cleaning compositions, if two or more anionic polymers containing sulfonic acid groups are included, the content of anionic polymers containing sulfonic acid groups shall be the total amount of these polymers. Furthermore, commercially available or synthetic anionic polymers containing sulfonic acid groups may be used.

[0049] The content of anionic polymers containing sulfonic acid groups in the post-CMP cleaning composition is not particularly limited, but is preferably more than 0.0002 ppm and 2% by mass or less, more preferably 0.001 ppm and 1% by mass or less, even more preferably 0.005 ppm and 5,000 ppm by mass or less, even more preferably more than 0.01 ppm and 2,500 ppm by mass or less, particularly preferably 0.05 ppm and 2,000 ppm by mass or less, and most preferably 0.1 ppm and 1,500% by mass or less. According to one embodiment, the content of anionic polymers containing sulfonic acid groups is 0.1 ppm and 1,000 ppm by mass or less. When the content of anionic polymers containing sulfonic acid groups is within the above range, residue on the surface of the polished object can be removed more efficiently after treatment with the post-CMP cleaning composition, and the intended effects of the present invention are more fully realized.

[0050] [Other polymers] The post-CMP cleaning composition according to this embodiment may further contain other polymers other than the nitrogen-containing nonionic polymer and the anionic polymer containing sulfonic acid groups. The other polymers can be cationic polymers, amphoteric polymers, nitrogen-free nonionic polymers, or anionic polymers that do not contain sulfonic acid groups. Furthermore, the other polymers are preferably water-soluble polymers. Here, a water-soluble polymer refers to a water-soluble polymer having the same repeating structural units (homopolymer) or a water-soluble polymer having different repeating structural units (copolymer), and is typically a compound with a weight-average molecular weight (Mw) of 1000 or more.

[0051] Examples of cationic polymers include polyethyleneimine (PEI), polyvinylamine, polyallylamine, polyvinylpyridine, and polymers of cationic acrylamide.

[0052] Examples of amphoteric polymers include copolymers of vinyl monomers having anionic groups and vinyl monomers having cationic groups, and vinyl-based amphoteric polymers having carboxybetaine groups or sulfobetaine groups. Specifically, examples include acrylic acid / dimethylaminoethyl methacrylic acid copolymers and acrylic acid / diethylaminoethyl methacrylic acid copolymers.

[0053] As a nitrogen-free nonionic polymer, any nonionic polymer that does not contain nitrogen atoms is acceptable, but it is preferable that it is a nonionic polymer that does not contain nitrogen atoms but contains oxygen atoms. Examples of nitrogen-free nonionic polymers include polyvinyl alcohol, polyvinyl ethers (polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether, etc.), polyalkylene oxides (polyethylene oxide, polypropylene oxide, polybutylene oxide, etc.), water-soluble polysaccharides such as polyglycerin, polyethylene glycol, polypropylene glycol, polybutylene glycol, hydroxyethylcellulose, alginic acid polyhydric alcohol esters, and dextrin derivatives.

[0054] In one embodiment, the content of polymers other than the nitrogen-containing nonionic polymer and the anionic polymer containing sulfonic acid groups is not particularly limited, but is, for example, 0.15% by mass or less, preferably 0.10% by mass or less, more preferably less than 0.10% by mass, and even more preferably 0.05% by mass or less, relative to the entire post-CMP cleaning composition. If the post-CMP cleaning composition contains two or more of the nitrogen-containing nonionic polymers and anionic polymers containing sulfonic acid groups, the content is the sum of these amounts. In one embodiment, the post-CMP cleaning composition according to this embodiment may not contain polymers other than the nitrogen-containing nonionic polymer and the anionic polymer containing sulfonic acid groups. Furthermore, the post-CMP cleaning composition according to this embodiment may or may not contain nitrogen-free nonionic polymers, but from the viewpoint of better demonstrating the effect of the nitrogen-containing nonionic polymers, it is preferable that the post-CMP cleaning composition according to this embodiment does not contain nitrogen-free nonionic polymers.

[0055] [solvent] The post-CMP cleaning composition according to this embodiment preferably contains a solvent. The solvent has the function of dispersing or dissolving each component. The solvent preferably contains water, and more preferably contains only water. Alternatively, the solvent may be a mixed solvent of water and an organic solvent for the dispersion or dissolution of each component. In this case, examples of organic solvents that can be used include acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, and propylene glycol, which are organic solvents that are miscible with water. Alternatively, these organic solvents may be used without mixing with water to disperse or dissolve each component, and then mixed with water. These organic solvents can be used individually or in combination of two or more.

[0056] From the viewpoint of preventing contamination of the polished object or interference with the action of other components, it is preferable that the water contains as few impurities as possible. For example, water with a total transition metal ion content of 100 ppb by mass or less is preferred. Here, the purity of the water can be increased by operations such as removing impurity ions using ion exchange resin, removing foreign matter by filtration, or distillation. Specifically, it is preferable to use, for example, deionized water (ion-exchanged water), pure water, ultrapure water, or distilled water. In this specification, the transition metal ion content can be measured, for example, by ICP emission spectrometry.

[0057] [Chelating agent] A post-CMP cleaning composition according to one embodiment of the present invention preferably contains a chelating agent. The inclusion of a chelating agent in the post-CMP cleaning composition further promotes the adsorption of nitrogen-containing nonionic polymers to the polished surface of the object to be polished, thereby further reducing residue. The chelating agent also has the function of adjusting the pH of the post-CMP cleaning composition. Furthermore, by forming chelates with impurities such as metal ions, the function of nitrogen-containing nonionic polymers and anionic polymers containing sulfonic acid groups can be improved. As the chelating agent, an organic compound having at least one phosphate group (-OP(=O)(OH)2) is preferred, and an organic compound having two or more phosphate groups (-OP(=O)(OH)2) is more preferred. That is, in one embodiment, the post-CMP cleaning composition of the present invention further contains a chelating agent having two or more phosphate groups. Examples of chelating agents include orthophosphate, methyl acid phosphate, ethyl acid phosphate, ethyl glycol acid phosphate, isopropyl acid phosphate, butyl acid phosphate, 2-ethylhexyl acid phosphate, pentetic acid, phytic acid, EDTA, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP, also called etidronic acid), polyphosphate, metaphosphate, hexametaphosphate, phosphonobutanetricarboxylic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, aminotrimethylenephosphonic acid, or salts thereof.

[0058] If the post-CMP cleaning composition contains a chelating agent, the content of the chelating agent is not particularly limited, but is preferably 0.003% by mass or more and 0.2% by mass or less, more preferably 0.005% by mass or more and 0.1% by mass or less, and even more preferably 0.006% by mass or more and 0.06% by mass or less, relative to the total mass of the post-CMP cleaning composition.

[0059] [Surfactants] The post-CMP cleaning composition according to this embodiment may further contain a surfactant. The type of surfactant is not particularly limited and may be a nonionic, anionic, cationic, or amphoteric surfactant. In one embodiment, the molecular weight of the surfactant may be less than 1,000.

[0060] Examples of nonionic surfactants include compounds other than the nitrogen-containing nonionic polymers mentioned above, such as alkyl ether types like polyoxyethylene lauryl ether and polyoxyethylene oleyl ether; alkylphenyl ether types like polyoxyethylene octylphenyl ether; alkyl ester types like polyoxyethylene laurate; alkylamine types like polyoxyethylene laurylamino ether; alkylamide types like polyoxyethylene lauric acid amide; polypropylene glycol ether types like polyoxyethylene polyoxypropylene ether; alkanolamide types like oleic acid diethanolamide; and allylphenyl ether types like polyoxyalkylene allylphenyl ether. In addition, propylene glycol, diethylene glycol, monoethanolamine, alcohol ethoxylates, alkylphenol ethoxylates, tertiary acetylene glycol, alkanolamides, etc., can also be used as nonionic surfactants. Note that since the nitrogen-containing nonionic polymers mentioned above can function as nonionic surfactants, it is not necessary to add a separate nonionic surfactant.

[0061] Examples of anionic surfactants include compounds other than the anionic polymers containing the sulfonic acid group mentioned above. These include carboxylic acid types such as sodium myristate, sodium palmitate, sodium stearate, sodium laurate, and potassium laurate; sulfate ester types such as sodium octyl sulfate; phosphate ester types such as lauryl phosphate and sodium lauryl phosphate; and sulfonic acid types such as sodium dioctyl sulfosuccinate and sodium dodecylbenzenesulfonate. Since the anionic polymers containing the sulfonic acid group mentioned above can function as anionic surfactants, it is not necessary to add a separate anionic surfactant.

[0062] Examples of cationic surfactants include amines such as laurylamine hydrochloride; quaternary ammonium salts such as polyethoxyamine and lauryltrimethylammonium chloride; and pyridium salts such as laurylpyridinium chloride.

[0063] Examples of amphoteric surfactants include lecithin, alkylamine oxides, alkylbetaines such as N-alkyl-N,N-dimethylammonium betaine, and sulfobetaines.

[0064] Surfactants can be used individually or in combination of two or more types. Furthermore, commercially available surfactants or synthetic surfactants may be used.

[0065] When the post-CMP cleaning composition contains a surfactant, the lower limit of the surfactant content is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more, based on 100% by mass of the total mass of the post-CMP cleaning composition. The upper limit of the surfactant content in the post-CMP cleaning composition is preferably 5% by mass or less, and more preferably 1% by mass or less, based on 100% by mass of the total mass of the post-CMP cleaning composition. When the post-CMP cleaning composition contains two or more surfactants, the surfactant content refers to the total amount of these surfactants.

[0066] <pH of post-CMP washing composition> The pH of the post-CMP cleaning composition according to this embodiment is preferably less than 7.0. When the pH of the post-CMP cleaning composition is less than 7.0, the potential on the surface of the polished object becomes positive, and the anionic polymer containing negatively charged sulfonic acid groups is more easily adsorbed onto the surface of the polished object by electrostatic attraction. This makes it easier for the surface of the polished object to be protected, and the zeta potential of the surface of the polished object during cleaning tends to become negative, further reducing the number of defects. The pH of the post-CMP cleaning composition is preferably 2 or more and less than 7.0, more preferably 2 or more and less than 6, even more preferably 2.3 or more and less than 5.5, even more preferably 2.4 or more and less than 5, particularly preferably 2.4 or more and less than 4, and most preferably 2.4 or more and less than 3.5.

[0067] [pH adjuster] The pH of the post-CMP cleaning composition can also be adjusted by anionic polymers containing sulfonic acid groups or chelating agents as described above, but the post-CMP cleaning composition may further contain a pH adjusting agent.

[0068] The pH adjusting agent is not particularly limited, and known pH adjusting agents used in the field of post-CMP cleaning compositions can be used. For example, known acids, bases, or salts thereof other than the chelating agents mentioned above can be used. Examples of pH adjusting agents include, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, lactic acid, malic acid, citric acid, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, melitic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and fumaroleic acid. Examples include carboxylic acids such as ruic acid, maleic acid, aconitic acid, and anthranilic acid; organic acids such as amino acids, sulfonic acids, and organic phosphonic acids; inorganic acids such as nitric acid, carbonic acid, hydrochloric acid, hypophosphorous acid, phosphorous acid, phosphonic acid, boric acid, and hydrofluoric acid; alkali metal hydroxides such as potassium hydroxide (KOH); alkali metal carbonates such as potassium carbonate (K2CO3) and sodium carbonate (Na2CO3); hydroxides of Group 2 elements (alkaline earth metals); ammonia (ammonium hydroxide); and organic bases such as quaternary ammonium hydroxide compounds.

[0069] pH adjusters may be synthetic or commercially available. Furthermore, these pH adjusters can be used individually or in combination of two or more.

[0070] The amount of pH adjuster in the post-CMP cleaning composition should be appropriately selected to achieve the desired pH value of the post-CMP cleaning composition.

[0071] The pH of the post-CMP cleaning composition shall be the value measured by the method described in the examples.

[0072] [Other additives] A post-CMP cleaning composition according to one embodiment of the present invention may contain other additives in any proportion as needed, as long as they do not hinder the effects of the present invention. However, components other than the essential components of the post-CMP cleaning composition according to one embodiment of the present invention may cause foreign matter (residue), so it is desirable not to add them unless necessary, and even if they are added, it is preferable to add as little as possible. Examples of other additives include antifungal agents (preservatives), dissolved gases, reducing agents, oxidizing agents, etc. The post-CMP cleaning composition according to this embodiment is preferably acidic. The post-CMP cleaning composition according to this embodiment also contains polymers. For this reason, it is preferable that the post-CMP cleaning composition according to this embodiment contains an antifungal agent (preservative). The antifungal agent that can be used in the post-CMP cleaning composition according to this embodiment is not particularly limited and can be appropriately selected depending on the type of polymer. Specifically, these include isothiazolinopropyl alcoholic preservatives such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one; methyl parahydroxybenzoate (methyl parahydroxybenzoate), butyl parahydroxybenzoate (butyl parahydroxybenzoate); phenylphenol (2-phenylphenol, 3-phenylphenol, 4-phenylphenol); unsaturated fatty acids such as sorbic acid; 1,2-alkanediols such as 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol; alkylglyceryl ethers such as 2-ethylhexylglyceryl ether (ethylhexylglycerin); capric acid, dehydroacetic acid, and phenoxyethanol.

[0073] The above-mentioned antifungal agents may be used individually or in combination of two or more types.

[0074] When a post-CMP cleaning composition contains an antifungal agent, the lower limit of the antifungal agent content (concentration) is not particularly limited, but it is preferably 0.000001% by mass or more, more preferably 0.000002% by mass or more, even more preferably 0.000005% by mass or more, and particularly preferably 0.00001% by mass or more, based on the total mass of the post-CMP cleaning composition. Similarly, the upper limit of the antifungal agent content (concentration) is not particularly limited, but it is preferably 3% by mass or less, more preferably 0.6% by mass or less, even more preferably 0.3% by mass or less, and particularly preferably 0.06% by mass or less. In other words, the content (concentration) of the antifungal agent in the post-CMP cleaning composition is preferably 0.000001% to 3% by mass, more preferably 0.000002% to 0.6% by mass, even more preferably 0.000005% to 0.3% by mass, and particularly preferably 0.00001% to 0.06% by mass, relative to the total mass of the post-CMP cleaning composition. Within this range, a sufficient effect for inactivating or destroying microorganisms can be obtained. If the post-CMP cleaning composition contains two or more antifungal agents, the above content refers to the total amount of these agents.

[0075] In other words, in one embodiment of the present invention, the post-CMP cleaning composition is substantially composed of a nitrogen-containing nonionic polymer, an anionic polymer containing a sulfonic acid group, and water, as well as at least one selected from the group consisting of a chelating agent, an antifungal agent, an organic solvent, a pH adjuster, and a surfactant. In one embodiment of the present invention, the post-CMP cleaning composition is substantially composed of a nitrogen-containing nonionic polymer, an anionic polymer containing a sulfonic acid group, and water, as well as at least one of a chelating agent, an antifungal agent, and an organic solvent. In one embodiment of the present invention, the post-CMP cleaning composition is substantially composed of a nitrogen-containing nonionic polymer, an anionic polymer containing a sulfonic acid group, water, a chelating agent, an antifungal agent, and an organic solvent.

[0076] In this embodiment, "the post-CMP cleaning composition is substantially composed of X" means that the total content of X exceeds 99% by mass (upper limit: 100% by mass) when the total mass of the post-CMP cleaning composition is taken as 100% by mass (relative to the post-CMP cleaning composition). Preferably, the post-CMP cleaning composition is composed of X (total content = 100% by mass). For example, "The post-CMP cleaning composition is substantially composed of a nitrogen-containing nonionic polymer, an anionic polymer containing a sulfonic acid group, and water, as well as at least one of a chelating agent, an antifungal agent, and an organic solvent" means that the total content of the nitrogen-containing nonionic polymer, the anionic polymer containing a sulfonic acid group, and water, as well as at least one of the chelating agent, antifungal agent, and organic solvent, exceeds 99% by mass (upper limit: 100% by mass) of the total mass of the post-CMP cleaning composition (with a total content of 100% by mass). It is preferable that the post-CMP cleaning composition is composed of a nitrogen-containing nonionic polymer, an anionic polymer containing a sulfonic acid group, and water, as well as at least one of a chelating agent, an antifungal agent, and an organic solvent (total content = 100% by mass).

[0077] To further improve the foreign matter removal effect, it is preferable that the post-chemical mechanical polishing cleaning composition (post-CMP cleaning composition) of the present invention substantially does not contain abrasive particles. Here, "substantially does not contain abrasive particles" means that the abrasive particle content relative to the entire post-CMP cleaning composition is less than 0.1% by mass (preferably less than 0.01% by mass). That is, in one embodiment, the post-CMP cleaning composition of the present invention has an abrasive particle content of less than 0.1% by mass, with the total mass of the post-CMP cleaning composition being 100% by mass.

[0078] Furthermore, in order to further improve the foreign matter removal effect, it is preferable that the post-CMP cleaning composition according to this embodiment substantially does not contain transition metal ions. Here, "substantially does not contain transition metal ions" means that the content of transition metal ions relative to the entire post-CMP cleaning composition is less than 0.1% by mass (preferably less than 0.01% by mass). That is, in one embodiment of the post-CMP cleaning composition of the present invention, the content of transition metal ions is less than 0.1% by mass, with the total mass of the post-CMP cleaning composition being 100% by mass.

[0079] <Electrical conductivity of post-chemical mechanical polishing and cleaning compositions (post-CMP cleaning compositions)> The electrical conductivity (EC) of the post-CMP cleaning composition according to this embodiment is not particularly limited, but is preferably 0.20 mS / cm or higher, more preferably 0.30 mS / cm or higher, and even more preferably 0.35 mS / cm or higher. Furthermore, the upper limit of the electrical conductivity (EC) of the post-CMP cleaning composition according to this embodiment is not particularly limited, but is preferably 0.95 mS / cm or lower, more preferably 0.90 mS / cm or lower, and even more preferably 0.60 mS / cm or lower. In other words, the electrical conductivity (EC) of the post-CMP cleaning composition according to this embodiment is preferably 0.20 mS / cm or higher and 0.95 mS / cm or lower, more preferably 0.30 mS / cm or higher and 0.90 mS / cm or lower, and even more preferably 0.35 mS / cm or higher and 0.60 mS / cm or lower. The electrical conductivity of the post-CMP cleaning composition can be adjusted by the type and amount of anionic polymers containing sulfonic acid groups, pH adjusters, etc. The electrical conductivity (EC) of the post-CMP cleaning composition can be measured by the method described in the examples.

[0080] <Water contact angle of polished objects during post-CMP cleaning treatment with post-CMP cleaning composition> As described above, it is presumed that using the post-CMP cleaning composition according to this embodiment allows for the removal of residues present on the surface of the polished object by adsorption of nitrogen-containing nonionic polymers (and anionic polymers containing sulfonic acid groups) onto the surface of the polished object. More specifically, it is presumed that in the post-chemical mechanical polishing cleaning composition according to this embodiment, nitrogen-containing nonionic polymers adsorb onto the surface of the Poly-Si substrate during the post-CMP cleaning treatment. If the molecular weight of the nitrogen-containing nonionic polymer is 2,000 or more, it is thought that the hydrophilicity of the Poly-Si substrate can be sufficiently improved, and the effect of reducing organic residues by the nitrogen-containing nonionic polymer can be fully demonstrated.

[0081] Here, a small water contact angle on the surface of a polished object indicates high wettability of that surface. This is thought to be due to the adsorption of nitrogen atoms of the nitrogen-containing nonionic polymer onto the surface of the polished object, improving its hydrophilicity. Therefore, the high wettability of the surface of a polished object supports the idea that the nitrogen-containing nonionic polymer is acting as described above.

[0082] Therefore, it is preferable for the water contact angle of the polished object during the post-CMP cleaning process to be small. For example, when the polished object is a substrate having a film containing polysilicon (Poly-Si substrate), a water contact angle of 40° or less is acceptable, 35° or less is preferred, 32° or less is more preferred, 20° or less is even more preferred, and 15° or less is particularly preferred. There is no particular lower limit to the water contact angle when the polished object is a substrate having a film containing polysilicon (Poly-Si substrate), but it should be 5° or more. The water contact angle of the polished object can be measured by the method described in the examples.

[0083] As described above, the post-CMP cleaning composition according to this embodiment can reduce the water contact angle of the polished object. Therefore, according to one embodiment of the present invention, a post-chemical mechanical polishing cleaning composition is provided that controls the water contact angle of polysilicon to 5° or more and 40° or less (more preferably 5° or more and 35° or less).

[0084] <Zeta potential of polished objects during post-CMP cleaning treatment with post-CMP cleaning composition> As described above, the post-CMP cleaning composition according to this embodiment contains an anionic polymer containing a sulfonic acid group, which allows for the control of the zeta potential of both the surface of the polished object and the surface of the residue (contaminants) to be negative. Therefore, it is presumed that the residue (contaminants) is efficiently detached from the polished object by utilizing electrostatic repulsion, and that re-adhesion to the polished object is suppressed.

[0085] More specifically, in the post-chemical mechanical polishing and cleaning composition according to this embodiment, it is hypothesized that during the post-CMP cleaning treatment, the nitrogen-containing nonionic polymer is adsorbed onto the anionic polymer containing sulfonic acid groups, and the anionic polymer containing sulfonic acid groups is then adsorbed onto the surface of the Si3N4 substrate. The anionicity of the anionic polymer containing sulfonic acid groups to which the nitrogen-containing nonionic polymer is adsorbed decreases. This is thought to suppress the negative affinity of the Si3N4 substrate by the anionic polymer containing sulfonic acid groups, and as a result, inhibit the abrasive residue reduction effect of the anionic polymer containing sulfonic acid groups. It is also possible that the nitrogen-containing nonionic polymer is adsorbed onto the surface of the Si3N4 substrate, inhibiting the adsorption of the anionic polymer containing sulfonic acid groups onto the Si3N4 substrate, thereby suppressing the negative affinity of the Si3N4 substrate by the anionic polymer containing sulfonic acid groups, and thus inhibiting the abrasive residue reduction effect of the anionic polymer containing sulfonic acid groups. However, when the weight-average molecular weight of the nitrogen-containing nonionic polymer is between 2,000 and 20,000, the anionic polymer containing sulfonic acid groups can sufficiently make the Si3N4 substrate negatively charged, and the effect of reducing abrasive residue by the anionic polymer containing sulfonic acid groups can be maintained. This negative charging of the Si3N4 substrate by the anionic polymer containing sulfonic acid groups can be confirmed by the zeta potential of the Si3N4 substrate.

[0086] As described above, the zeta potential of the surface of the polished object after post-CMP cleaning is preferably a negative value. For example, when the polished object is a substrate (Si3N4 substrate) having a film containing silicon nitride, the zeta potential is acceptable if it is -5mV or less, preferably less than -5mV, more preferably -10mV or less, even more preferably -15mV or less, particularly preferably -20mV or less, and most preferably -25mV or less. The zeta potential of the surface of the polished object after post-CMP cleaning can be estimated by the method described in the examples.

[0087] As described above, the post-CMP cleaning composition according to this embodiment can control the zeta potential of the polished object to a negative value. Therefore, according to one embodiment of the present invention, a post-chemical mechanical polishing cleaning composition is provided that controls the zeta potential of the silicon nitride surface to -50mV or more and -10mV or less (more preferably -50mV or more and -20mV or less).

[0088] <Method for producing post-chemical mechanical polishing and cleaning compositions (post-CMP cleaning compositions)> The present invention provides a method for producing a post-CMP cleaning composition, for example, by stirring and mixing a nitrogen-containing nonionic polymer, an anionic polymer containing a sulfonic acid group, a solvent, and other components as needed. The temperature during mixing of the components is not particularly limited, but 10°C to 40°C is preferred, and heating may be used to increase the dissolution rate. The mixing time is also not particularly limited.

[0089] <Post-chemical mechanical polishing and cleaning method (post-CMP cleaning method; surface treatment method)> Another embodiment of the present invention is a post-chemical mechanical polishing and cleaning method (also referred to herein as "post-CMP cleaning method" or "surface treatment method") which includes performing a post-chemical mechanical polishing and cleaning treatment (also referred to herein as "post-CMP cleaning treatment" or "surface treatment") on a polished object using the above-mentioned post-chemical mechanical polishing and cleaning composition (post-CMP cleaning composition). In this specification, a post-chemical mechanical polishing and cleaning method (post-CMP cleaning method) refers to a method for reducing residue on the surface of a polished object, and is a method for performing cleaning in a broad sense.

[0090] According to one embodiment of the present invention, a post-CMP cleaning treatment method can sufficiently remove residue remaining on the surface of a polished object. That is, according to another embodiment of the present invention, a method for reducing residue on the surface of a polished object is provided, which involves performing a post-chemical mechanical polishing cleaning treatment (post-CMP cleaning treatment) on a polished object using the above-mentioned post-chemical mechanical polishing cleaning composition (post-CMP cleaning composition). Furthermore, according to yet another embodiment of the present invention, a post-chemical mechanical polishing cleaning treatment method (post-CMP cleaning treatment method) is also provided, which involves performing a post-chemical mechanical polishing cleaning treatment (post-CMP cleaning treatment) on a polished object containing a silicon-containing material using the above-mentioned post-chemical mechanical polishing cleaning composition (post-CMP cleaning composition) to reduce residue on the surface of the polished object. Here, the silicon-containing material includes at least one selected from the group consisting of silicon oxide, polysilicon, and silicon nitride.

[0091] A post-CMP cleaning treatment method according to one embodiment of the present invention is performed by directly contacting the post-CMP cleaning composition according to this embodiment with a polished object.

[0092] Post-chemical mechanical polishing and cleaning treatment methods (post-CMP cleaning treatment methods) mainly include (I) a rinse polishing treatment method and (II) a cleaning treatment method. That is, according to one embodiment of the present invention, the above post-chemical mechanical polishing and cleaning treatment (post-CMP cleaning treatment) is preferably performed by a rinse polishing treatment or a cleaning treatment. That is, the above post-chemical mechanical polishing and cleaning treatment method (post-CMP cleaning treatment method) is preferably a rinse polishing treatment method or a cleaning treatment method. Rinse polishing treatment and cleaning treatment are performed to remove foreign matter (particles, metal contamination, organic residue, pad debris, etc.) from the surface of the polished object and to obtain a clean surface. The above (I) and (II) will be described below.

[0093] (I) Rinse polishing treatment The post-CMP cleaning composition according to this embodiment is suitably used in rinse polishing. That is, the post-CMP cleaning composition according to one embodiment of the present invention can be suitably used as a rinse polishing composition. Rinse polishing is performed on a polishing platen with a polishing pad attached, after the final polishing (finish polishing) of the object to be polished, for the purpose of removing foreign matter from the surface of the object to be polished. At this time, the rinse polishing is performed by bringing the post-CMP cleaning composition according to this embodiment into direct contact with the polished object. As a result, foreign matter on the surface of the polished object is removed by the frictional force (physical action) of the polishing pad and the chemical action of the post-CMP cleaning composition. Among the foreign matter, particles and organic residues are particularly easy to remove by physical action. Therefore, in rinse polishing, particles and organic residues can be effectively removed by utilizing the friction with the polishing pad on the polishing platen.

[0094] In other words, in this specification, rinse polishing treatment, rinse polishing method, and rinse polishing process refer to treatment, methods, and processes, respectively, that use a polishing pad to reduce residue on the surface of an object to be treated with post-CMP cleaning.

[0095] Specifically, the rinse polishing process can be performed by placing the polished surface of the workpiece after the polishing process on the polishing platen of the polishing apparatus, bringing the polishing pad into contact with the polished semiconductor substrate, and supplying a post-CMP cleaning composition to the contact area while sliding the polished workpiece and the polishing pad relative to each other.

[0096] As a polishing device, a general polishing device can be used that has a holder for holding the object to be polished, a motor with adjustable rotation speed, and a polishing platen to which a polishing pad (abrasive cloth) can be attached.

[0097] The rinse polishing process can be carried out using either a single-sided polishing device or a double-sided polishing device. Furthermore, it is preferable that the polishing device includes a discharge nozzle for a post-CMP cleaning composition in addition to a discharge nozzle for the polishing composition. The operating conditions of the polishing device during the rinse polishing process are not particularly limited and can be set appropriately by those skilled in the art.

[0098] As the polishing pad, general nonwoven fabrics, polyurethanes, and porous fluororesins can be used without particular limitations. Preferably, the polishing pad has grooves that allow the post-CMP cleaning composition to accumulate.

[0099] There are no particular restrictions on the rinse polishing conditions. For example, the rotation speed of the polishing platen and the rotation speed of the head (carrier) can be 10 rpm (0.17 s). -1 ) or more 100rpm(1.67s -1 It is preferable that the pressure applied to the polished workpiece (polishing pressure) is 0.5 psi (3.4 kPa) or more and 10 psi (68.9 kPa) or less. The method of supplying the post-CMP cleaning composition to the polishing pad is not particularly limited, and for example, a method of continuous supply using a pump or the like (flow-through) is employed. There is no limit to the amount supplied, but it is preferable that the surface of the polishing pad is always covered with the post-CMP cleaning composition, and it is preferable that it is 10 mL / min or more and 5000 mL / min or less. The rinsing polishing time is also not particularly limited, but it is preferable that it is 5 seconds or more and 180 seconds or less.

[0100] After rinsing and polishing with a post-CMP cleaning composition according to one embodiment of the present invention, it is preferable that the polished object (object subjected to post-chemical mechanical polishing and cleaning treatment) is lifted up and removed while applying the post-CMP cleaning composition according to one embodiment of the present invention.

[0101] (II) Washing process The post-CMP cleaning composition according to this embodiment may be used in a cleaning process. That is, the post-CMP cleaning composition according to one embodiment of the present invention can preferably be used as a cleaning composition. The cleaning process is preferably performed after the final polishing (finish polishing) of the object to be polished, after the rinse polishing process described above, or after the rinse polishing process using a rinse polishing composition other than the post-CMP cleaning composition of the present invention, for the purpose of removing foreign matter from the surface of the polished object (object to be cleaned). Note that the cleaning process and the rinse polishing process described above are classified according to the location in which these processes are performed. The cleaning process is a surface treatment performed in a location other than on the polishing platen, and is preferably a surface treatment performed after the polished object has been removed from the polishing platen. In the cleaning process as well, the post-CMP cleaning composition according to this embodiment can be brought into direct contact with the polished object to remove foreign matter from the surface of the object.

[0102] Examples of cleaning methods include (i) holding the polished object and bringing a cleaning brush into contact with one or both sides of the polished object, while supplying a post-CMP cleaning composition to the contact area and rubbing the surface of the polished object with the cleaning brush; and (ii) immersing the polished object in the post-CMP cleaning composition and performing ultrasonic treatment or agitation (dip method). In such methods, foreign matter on the surface of the polished object is removed by the frictional force of the cleaning brush, the mechanical force generated by ultrasonic treatment or agitation, and the chemical action of the post-CMP cleaning composition.

[0103] In the method described in (i) above, the method of contacting the polished object with the post-CMP cleaning composition is not particularly limited, but examples include a spin type in which the polished object is rotated at high speed while the post-CMP cleaning composition is flowed onto the polished object from a nozzle, and a spray type in which the post-CMP cleaning composition is sprayed onto the polished object for cleaning.

[0104] From the viewpoint of enabling more efficient contamination removal in a shorter time, the cleaning process is preferably a spin type and / or a spray type, and more preferably a spin type.

[0105] Apparatus for performing such cleaning processes include batch-type cleaning devices that simultaneously perform post-CMP cleaning on multiple polished workpieces contained in a cassette, and single-wafer cleaning devices that perform post-CMP cleaning on a single polished workpiece mounted in a holder. From the viewpoint of shortening cleaning time, the method using a single-wafer cleaning device is preferred.

[0106] Furthermore, a polishing apparatus equipped with a cleaning device for removing the polished object from the polishing platen and then scrubbing the object with a cleaning brush is also available. By using such a polishing apparatus, the cleaning process for polished objects can be carried out more efficiently.

[0107] Such a polishing apparatus can be a general-purpose polishing apparatus that includes a holder for holding the polished workpiece, a motor with adjustable rotation speed, a cleaning brush, etc. Either a single-sided polishing apparatus or a double-sided polishing apparatus may be used. When a rinse polishing process is performed after the CMP process, it is more efficient and preferable to perform the cleaning process using the same apparatus as the polishing apparatus used in the rinse polishing process.

[0108] The cleaning brush is not particularly limited, but is preferably a resin brush. The material of the resin brush is not particularly limited, but PVA (polyvinyl alcohol) is preferred. The cleaning brush is more preferably a PVA sponge.

[0109] There are no particular restrictions on the cleaning conditions, and they can be set appropriately depending on the type of polished object and the type and amount of residue to be removed. For example, the rotation speed of the cleaning brush is 10 rpm (0.17 s). -1 ) or more 200rpm(3.33s -1The rotational speed of the polished object must be less than or equal to 10 rpm (0.17 s). -1 ) or more 100rpm(1.67s -1 It is preferable that each of these values ​​is less than or equal to the following. The pressure applied to the polished workpiece (polishing pressure) is preferably 0.5 psi (3.4 kPa) or more and 10 psi (68.9 kPa) or less. The method of supplying the post-CMP cleaning composition to the cleaning brush is not particularly limited, and for example, a method of continuous supply using a pump or the like (flow-through) can be employed. There is no limit to the amount supplied, but it is preferable that the surface of the cleaning brush and the polished workpiece is always covered with the post-CMP cleaning composition, and it is preferable that it is 10 mL / min or more and 5000 mL / min or less. The cleaning time is also not particularly limited, but for the step using the post-CMP cleaning composition according to one embodiment of the present invention, it is preferable that it is 5 seconds or more and 180 seconds or less. Within this range, it is possible to remove foreign matter more effectively.

[0110] The temperature of the post-CMP cleaning composition during cleaning is not particularly limited and is usually at room temperature, but it may be heated to approximately 40°C to 70°C, as long as it does not impair performance.

[0111] In the method described in (ii) above, there are no particular restrictions on the conditions for the immersion cleaning method, and known methods can be used.

[0112] Before performing the post-CMP cleaning treatment by method (I) or (II) described above, a rinse with water may be performed.

[0113] (Post-cleaning process) Furthermore, as a post-CMP cleaning treatment method, it is preferable to further clean the polished object after the post-CMP cleaning treatment described in (I) or (II) above using a post-CMP cleaning composition according to one embodiment of the present invention. In this specification, this cleaning treatment is referred to as the post-cleaning treatment. The post-cleaning treatment is not particularly limited, but examples include simply pouring water over the polished object, or simply immersing the polished object in water. Also, similar to the post-CMP cleaning treatment by method (II) described above, examples include a method in which the surface of the polished object is rubbed with a cleaning brush while holding the polished object and bringing the cleaning brush into contact with one or both sides of the polished object, and supplying water or an aqueous solution (e.g., an NH3 aqueous solution) to the contact area, or supplying water and an aqueous solution (e.g., an NH3 aqueous solution) in any order (supplying water first and then the aqueous solution, or supplying the aqueous solution first and then water), or a method in which the polished object is immersed in water and subjected to ultrasonic treatment or stirring (dip method). Among these methods, it is preferable to hold the polished object to be polished and bring the cleaning brush into contact with one or both sides of the polished object to be polished, and then rub the surface of the polished object with the cleaning brush while supplying water or an aqueous solution (e.g., an NH3 aqueous solution) or water and an aqueous solution (e.g., an NH3 aqueous solution) to the contact area in any order (supplying water first, then the aqueous solution, or supplying the aqueous solution first, then water). For the apparatus and conditions of the post-cleaning treatment, refer to the description of the treatment in (II) above. Here, it is particularly preferable to use deionized water as the water used in the post-cleaning treatment.

[0114] By performing a post-CMP cleaning treatment with the post-CMP cleaning composition according to one embodiment of the present invention, the residue becomes extremely easy to remove. Therefore, after performing a post-CMP cleaning treatment with the post-CMP cleaning composition according to one embodiment of the present invention, further cleaning with water results in extremely effective removal of the residue.

[0115] Furthermore, it is preferable to dry the polished workpiece after post-CMP cleaning or post-cleaning by removing any water droplets adhering to the surface using a spin dryer or the like. Alternatively, the surface of the polished workpiece may be dried by air blow drying.

[0116] <Manufacturing method for semiconductor substrates> A post-CMP cleaning method according to one embodiment of the present invention is preferably applied when the polished object to be polished is a polished semiconductor substrate. That is, according to another embodiment of the present invention, a method for manufacturing a semiconductor substrate is also provided, in which the polished object to be polished is a polished semiconductor substrate, and the polished semiconductor substrate is subjected to the post-CMP cleaning method described above to reduce residue on the surface of the polished semiconductor substrate. Accordingly, according to the present invention, a method for manufacturing a semiconductor substrate is provided, comprising a polishing step of obtaining a polished semiconductor substrate by polishing a pre-polished semiconductor substrate containing a silicon-containing material, for example, at least one selected from the group consisting of silicon oxide, polysilicon and silicon nitride, using a polishing composition containing abrasive particles, and a post-chemical mechanical polishing cleaning step (also referred to herein as the "post-CMP cleaning step" or "surface treatment step") of reducing residue containing abrasive particles on the surface of the polished semiconductor substrate using the post-chemical mechanical polishing cleaning composition (post-CMP cleaning composition).

[0117] Details of the semiconductor substrate to which this manufacturing method is applied are as described in the description of the polished object to be post-CMP cleaned with the post-CMP cleaning composition described above.

[0118] Furthermore, the method for manufacturing a semiconductor substrate is not particularly limited, as long as it includes a post-CMP cleaning process using a post-CMP cleaning composition according to one embodiment of the present invention to the surface of the polished semiconductor substrate. Examples of such manufacturing methods include a method having a polishing step and a cleaning step for forming a polished semiconductor substrate. Another example is a method that includes a rinse polishing step between the polishing and cleaning steps, in addition to the polishing and cleaning steps. Each of these steps will be described below.

[0119] [Polishing process] A polishing step that may be included in the manufacturing method of a semiconductor substrate is a step of polishing the semiconductor substrate to form a polished semiconductor substrate.

[0120] The polishing process is not particularly limited as long as it is a process for polishing a semiconductor substrate, but it is a chemical mechanical polishing (CMP) process. Furthermore, the polishing process may consist of a single step or multiple steps. Examples of a polishing process consisting of multiple steps include a process in which a preliminary polishing (rough polishing) step is followed by a finish polishing step, or a process in which one or more secondary polishing steps are performed after a primary polishing step, followed by a finish polishing step. The post-CMP cleaning process using the post-CMP cleaning composition according to this embodiment is preferably performed after the finish polishing step.

[0121] As the polishing composition, known polishing compositions can be used as appropriate depending on the characteristics of the semiconductor substrate. The polishing composition is not particularly limited, but for example, those containing abrasive grains, a solvent, a water-soluble polymer, and a pH adjuster can be preferably used. Specific examples of such polishing compositions include those containing silicon dioxide (e.g., colloidal silica), polyvinylpyrrolidone, ammonia, and water.

[0122] The abrasive grains may be inorganic particles, organic particles, or organic-inorganic composite particles. Specific examples of inorganic particles include particles made of metal oxides such as silicon dioxide, alumina, ceria, and titania, as well as silicon nitride particles, silicon carbide particles, and boron nitride particles. Specific examples of organic particles include polymethyl methacrylate (PMMA) particles. The abrasive grains may be commercially available or synthetically produced. Furthermore, the abrasive grains may be surface-modified. The abrasive grains may be used individually or in combination of two or more types.

[0123] The lower limit of the average primary particle diameter of the abrasive grains is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm or more, and still more preferably 30 nm or more. Within this range, a high polishing speed can be maintained, making it suitable for use in the rough polishing process. The upper limit of the average primary particle diameter of the abrasive grains is preferably 200 nm or less, more preferably 150 nm or less, and still more preferably 100 nm or less. In some embodiments, the average primary particle diameter may be 75 nm or less, 60 nm or less, or 50 nm or less. Within this range, the occurrence of defects on the surface of the polished object after polishing can be further suppressed. The average primary particle diameter of the abrasive grains is calculated, for example, based on the specific surface area of ​​the abrasive grains measured by the BET method.

[0124] The lower limit of the average secondary particle diameter of the abrasive grains is preferably 15 nm or more, more preferably 30 nm or more, even more preferably 40 nm or more, even more preferably 50 nm or more, and particularly preferably 60 nm or more. Within this range, a high polishing speed can be maintained. The upper limit of the average secondary particle diameter of the abrasive grains is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, even more preferably 100 nm or less, and particularly preferably 80 nm or less. Within this range, the occurrence of defects on the surface of the polished object after polishing can be further suppressed. The average secondary particle diameter of the abrasive grains can be measured by dynamic light scattering. For example, it can be measured using the "FPAR-1000" model or an equivalent product manufactured by Otsuka Electronics Co., Ltd.

[0125] When the polishing composition is used as is as a polishing fluid, the abrasive content is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, and even more preferably 1.0% by mass or more, relative to the polishing composition. Increasing the abrasive content improves the polishing speed. Also, when the polishing composition is used as is as a polishing fluid, from the viewpoint of preventing scratches, the abrasive content is usually appropriate at 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less. Reducing the abrasive content is also preferable from an economic standpoint. Note that when two or more types of abrasives are used in combination, the above content refers to the total content of the two or more types of abrasives.

[0126] The pH adjusters and solvents are the same as those specified in the [pH adjusters] and [solvents] sections above, respectively, so their explanation is omitted here.

[0127] As the polishing device, a general polishing device having a holder for holding the polishing object and a motor etc. whose rotation speed can be changed, and a polishing platen to which a polishing pad (polishing cloth) can be attached can be used. As the polishing device, either a single-sided polishing device or a double-sided polishing device may be used.

[0128] As the polishing pad, general non-woven fabric, polyurethane, porous fluororesin, etc. can be used without particular limitation. It is preferable that the polishing pad is subjected to groove processing so that the polishing liquid accumulates.

[0129] There are also no particular restrictions on the polishing conditions. For example, the rotation speed of the polishing platen and the rotation speed of the head (carrier) are preferably 10 rpm (0.17 s -1 ) or more and 100 rpm (1.67 s -1 ) or less, and the pressure applied to the polishing object (polishing pressure) is preferably 0.5 psi (3.4 kPa) or more and 10 psi (68.9 kPa) or less. The method of supplying the polishing composition to the polishing pad is also not particularly limited. For example, a method of continuously supplying with a pump etc. (flowing over) is adopted. There is no limitation on this supply amount, but it is preferable that the surface of the polishing pad is always covered with the polishing composition, and it is preferably 10 mL / min or more and 5000 mL / min or less. The polishing time is also not particularly limited, but for the step of using the polishing composition, it is preferably 5 seconds or more and 180 seconds or less.

[0130] <Post chemical mechanical polishing cleaning treatment step (Post CMP cleaning treatment step)> The Post CMP cleaning treatment step refers to a step of reducing residues on the surface of the polished polishing object using the Post CMP cleaning composition according to this embodiment. In the method of manufacturing a semiconductor substrate, after the rinse polishing step, a cleaning step as the Post CMP cleaning treatment step may be performed, or only the rinse polishing step or only the cleaning step may be performed.

[0131] (Rinse polishing step) A rinse polishing step may be provided between the polishing step and the cleaning step in a semiconductor substrate manufacturing method. The rinse polishing step is a step of reducing foreign matter on the surface of a polished object (polished semiconductor substrate) by a post-CMP cleaning treatment method (rinse polishing treatment method) according to one embodiment of the present invention.

[0132] Details of the rinse polishing method used in the rinse polishing process are as described in the above explanation of the rinse polishing treatment.

[0133] (Washing process) The cleaning step may be provided after the polishing step or after the rinse polishing step in the semiconductor substrate manufacturing method. The cleaning step is a step of reducing foreign matter on the surface of the polished object (polished semiconductor substrate) by a post-CMP cleaning treatment method (cleaning method) according to one embodiment of the present invention.

[0134] Details of the cleaning method used in the cleaning process are as described in the above explanation of the cleaning method.

[0135] While embodiments of the present invention have been described in detail, these are descriptive and illustrative, and not limiting, and it is clear that the scope of the present invention should be interpreted by the appended claims.

[0136] The present invention encompasses the following embodiments and forms.

[0137] [1] A post-chemical mechanical polishing and cleaning composition comprising an anionic polymer containing a sulfonic acid group and a nitrogen-containing nonionic polymer having a weight-average molecular weight of 2,000 or more and 20,000 or less; [2] The post-chemical mechanical polishing and cleaning composition according to [1] above, wherein the nitrogen-containing nonionic polymer is contained in an amount of 10 ppm by mass or more and 1% by mass or less based on the total mass of the post-chemical mechanical polishing and cleaning composition; [3] The post-chemical mechanical polishing and cleaning composition according to [1] or [2] above, which contains an anionic polymer containing the sulfonic acid group in an amount of 0.1 ppm by mass or more and 1000 ppm by mass or less based on the total mass of the post-chemical mechanical polishing and cleaning composition; [4] A post-chemical mechanical polishing and cleaning composition according to any of [1] to [3] above, which controls the water contact angle of polysilicon to 40° or less; [5] A post-chemical mechanical polishing and cleaning composition according to any of [1] to [4] above, which controls the zeta potential of the silicon nitride surface to -20 mV or less; [6] Post-chemical mechanical polishing and cleaning compositions according to any of [1] to [5] above, which substantially do not contain abrasive particles; [7] A post-chemical mechanical polishing and cleaning method for reducing residue on the surface of a polished object by surface-treating the polished object with a post-chemical mechanical polishing and cleaning composition described in any of [1] to [6] above, the polished object containing at least one selected from the group consisting of silicon dioxide, polysilicon, and silicon nitride; [8] A post-chemical mechanical polishing and cleaning method described in [7] above, which is a rinse polishing method or a cleaning method; [9] The polished object to be polished is a polished semiconductor substrate, A polishing step to obtain a polished semiconductor substrate by polishing a pre-polishing semiconductor substrate containing at least one selected from the group consisting of silicon dioxide, polysilicon, and silicon nitride using a polishing composition containing abrasive particles, A post-chemical mechanical polishing and cleaning process for reducing residue on the surface of the polished semiconductor substrate using any of the post-chemical mechanical polishing and cleaning compositions described in any of [1] to [6] above, A method for manufacturing a semiconductor substrate that includes [the specified component]. [Examples]

[0138] The present invention will be described 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. Unless otherwise specified, "%", "ppm", and "parts" mean "mass%", "mass ppm", and "mass parts", respectively. In addition, in the following examples, unless otherwise specified, the operations were carried out under conditions of room temperature (25°C) and relative humidity of 40%RH to 50%RH.

[0139] [Preparation of polymers] The following nitrogen-containing nonionic polymers and anionic polymers containing sulfonic acid groups were prepared.

[0140] "Nitrogen-containing nonionic polymer" • Polyvinylpyrrolidone; weight-average molecular weight 1,000 • Polyvinylpyrrolidone; weight-average molecular weight 10,000 • Polyvinylpyrrolidone; weight-average molecular weight 20,000 • Polyvinylpyrrolidone; weight-average molecular weight 30,000 • N-ethylpyrrolidone "Anionic polymer containing sulfonic acid groups" • Sodium salt of a copolymer of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid (hereinafter also referred to as "(acrylic acid / sulfonic acid) copolymer") (Product name: Aron A-6012 (Toagosei Co., Ltd.)); weight-average molecular weight 12,000 • Polyacrylic acid; weight-average molecular weight 15,000 The weight-average molecular weight of the above polymers was measured by the following method.

[0141] [Measurement of weight-average molecular weight (Mw) of polymers] The weight-average molecular weight (Mw) of the polymer was determined using the weight-average molecular weight (converted to polyethylene glycol) measured by gel permeation chromatography (GPC). The weight-average molecular weight was measured using the following equipment and conditions: GPC equipment: Manufactured by Shimadzu Corporation Model: Prominence + ELSD detector (ELSD-LTII) Column: VP-ODS (manufactured by Shimadzu Corporation) Mobile phase A:MeOH B: 1% aqueous solution of acetic acid Flow rate: 1mL / min Detector: ELSD, temp. 40℃, Gain 8, N2GAS 350kPa Oven temperature: 40℃ Injection volume: 40μL.

[0142] [Measurement of pH of post-CMP cleaning composition] The pH of the post-CMP cleaning composition (liquid temperature: 25°C) was confirmed using a pH meter (product name: LAQUA®, manufactured by Horiba, Ltd.).

[0143] [Electrical conductivity of post-CMP cleaning compositions] The electrical conductivity (EC) of the post-CMP cleaning composition was measured using a benchtop electrical conductivity meter (manufactured by Horiba, Ltd., model number: DS-71 LAQUA®).

[0144] [Preparation of post-CMP cleaning composition] (Example 1) Post-CMP cleaning composition A1 was prepared by stirring and mixing the following at 25°C for 5 minutes: polyvinylpyrrolidone with a weight-average molecular weight of 10,000 as a nitrogen-containing nonionic polymer; (acrylic acid / sulfonic acid) copolymer with a weight-average molecular weight of 12,000 as an anionic polymer containing sulfonic acid groups; water (deionized water) as a solvent; 1-hydroxyethane-1,1-diphosphonic acid (hereinafter referred to as "HEDP") (product name: Dequest® 2010EL (Italmatch Japan Co., Ltd.)) as a chelating agent; ammonia (product name: EL ammonia water (Kanto Chemical Co., Ltd.)) as a pH adjuster; and an antifungal agent (preservative) (San-ai Back R-30 (manufactured by San-ai Obli Co., Ltd.)).

[0145] Here, in post-CMP cleaning composition A1, the content of nitrogen-containing nonionic polymer is 125 ppm by mass relative to the total mass of post-CMP cleaning composition A1; the content of anionic polymer containing sulfonic acid groups is 100 ppm by mass relative to the total mass of post-CMP cleaning composition A1; the content of chelating agent is 150 ppm by mass relative to the total mass of post-CMP cleaning composition A1; the content of pH adjuster is an amount that makes the pH of post-CMP cleaning composition A1 3.1; and the content of antifungal agent is 0.000025% by mass relative to the total mass of post-CMP cleaning composition A1.

[0146] (Examples 2-14, Comparative Examples 1-6) Post-CMP cleaning compositions A2 to A14 and post-CMP cleaning compositions B1 to B6 were prepared in the same manner as in Example 1, except that the types and / or content of nitrogen-containing nonionic polymers and anionic polymers containing sulfonic acid groups were changed as shown in Tables 1 and 2 below.

[0147] In Tables 1 and 2, nitrogen-containing nonionic polymers are denoted as "N-containing nonionic polymers," and (acrylic acid / sulfonic acid) copolymers are denoted as "AA / SA copolymers."

[0148] In addition, in Tables 1 and 2, "PVP" represents polyvinylpyrrolidone. Furthermore, in Tables 1 and 2, a hyphen ("-") indicates that the compound was not added.

[0149] [Preparation of polished objects to be polished] Polished objects were prepared after being polished using the following chemical mechanical polishing (CMP) process.

[0150] (CMP process) As materials to be polished, we prepared (1) a silicon wafer (also referred to as a Poly-Si substrate or polysilicon substrate in this specification) with a 5000 Å thick polycrystalline silicon film formed on its surface (300 mm, blanket wafer, manufactured by D&X Corporation), and (2) a silicon wafer (also referred to as a Si3N4 substrate) (300 mm, blanket wafer, manufactured by Advantech Corporation) with a 2500 Å thick silicon nitride (Si3N4) film formed on its surface. Note that 1 Å = 0.1 nm.

[0151] The Poly-Si and Si3N4 substrates prepared above were polished using a polishing composition (composition: a slurry containing 10% by mass of colloidal silica (average primary particle size 35 nm, average secondary particle size 70 nm), 0.25% by mass of polyvinylpyrrolidone, and 0.33% by mass of ammonia (ammonium hydroxide), diluted five times) under the following conditions. Note: 1 rpm = 0.017 s -1 That is the case.

[0152] <Polishing equipment and polishing conditions> Polishing equipment: Applied Materials Reflexion LK 300mm single-sided CMP polishing machine. Polishing pad: Foamed polyurethane pad H800, manufactured by Fuji Spinning Holdings Co., Ltd. Conditioner (dresser): Nylon brush (made by 3M) Polishing pressure: 2.0 psi (1 psi = 6894.76 Pa, the same applies below) Polishing plate rotation speed: 80 rpm Head rotation speed: 80 rpm Supply of polishing composition: flow-through Polishing composition supply amount: 200mL / min Polishing time: 60 seconds.

[0153] [Post-chemical mechanical polishing and cleaning treatment (post-CMP cleaning treatment)] (Rinse polishing) After polishing the surface of the object to be polished in the above CMP process, the polished object was removed from the polishing platen. Subsequently, within the same polishing apparatus, the polished object was mounted on another polishing platen, and a rinse polishing treatment was performed on the surface of the polished object using post-CMP cleaning compositions A1-A14 and B1-B6 prepared in Examples 1-14 and Comparative Examples 1-6 under the following conditions.

[0154] <Rinse polishing equipment and rinse polishing conditions> Polishing equipment: Applied Materials Reflexion LK 300mm single-sided CMP polishing machine. Polishing pad: Foamed polyurethane pad H800, manufactured by Fuji Spinning Holdings Co., Ltd. Conditioner (dresser): Nylon brush (made by 3M) Polishing pressure: 1.0 psi Plate rotation speed: 80 rpm Supply of post-CMP cleaning composition: flow-through Post-CMP cleaning composition supply rate: 300 mL / min Polishing time: 60 seconds.

[0155] (Post-cleaning) After rinsing and polishing, the substrate surface was brush-cleaned with a 0.3% by mass NH3 aqueous solution for 20 seconds, followed by rinsing with deionized water for 40 seconds to obtain a polished object that had undergone rinsing and polishing.

[0156] [Evaluation 1: Residue count measurement] The number of residues on the surface of the polished substrates obtained in the [Preparation of Polished Objects] section above was subjected to cleaning treatment according to the method described in the [Post-Chemical Mechanical Polishing Cleaning Treatment (Post-CMP Cleaning Treatment)] section above, and the number of residues on the surface of the Poly-Si substrate and Si3N4 substrate was evaluated. Specifically, using the Surfscan® SP5 optical inspection machine manufactured by KLA-Tencor Co., Ltd., the number of residues with a diameter of 40 nm or more (abrasive residues) and the number of residues with a diameter of 70 nm or more (abrasive residues) were counted in the remaining portion after excluding a 5 mm wide portion from the outer edge of one side of the polished Poly-Si substrate and Si3N4 substrate (the portion from 0 mm to 5 mm wide when the outer edge is set to 0 mm). Subsequently, the number of abrasive residues and organic residues for the polished Poly-Si substrate and Si3N4 substrate were measured by SEM observation using a Review SEM RS6000 manufactured by Hitachi High-Tech Corporation. First, 100 residues were sampled from the remaining portion of one side of polished Poly-Si and Si3N4 substrates, excluding a 5mm wide area from the outer edge, using SEM observation. Next, the type of residue (abrasive grains or organic residue) was identified from the 100 sampled residues by visual SEM observation, and the number of abrasive grain residues (SiO2 residues) and organic residues (pad debris, polymers, etc.) was confirmed. The results are shown in Tables 1 and 2 below. Note that there were 0 abrasive grain residues with a diameter of 70nm or more on the Poly-Si substrates after rinsing and polishing with post-CMP cleaning compositions A1-A14 and B1-B6, and there were fewer than 5 organic residues on the Si3N4 substrates. Since post-CMP cleaning compositions A1-A14 and B1-B6 all performed similarly, detailed evaluation results have been omitted.

[0157] The number of abrasive grain residues (SiO2 residues) should be as small as possible. For example, the number of abrasive grain residues with a diameter of 40 nm or more on a Si3N4 substrate is acceptable if it is 800 or less, preferably 250 or less, more preferably 200 or less, even more preferably 100 or less, particularly preferably 70 or less, and most preferably 50 or less.

[0158] Furthermore, it is preferable to minimize the number of organic residues (such as pad debris and polymers). For example, the number of organic residues (such as pad debris and polymers) with a diameter of 70 nm or more on the Poly-Si substrate is acceptable if it is 800 or less, preferably 500 or less, more preferably 250 or less, even more preferably 200 or less, particularly preferably 150 or less, and most preferably 100 or less.

[0159] The total number of residues, which is the sum of the number of abrasive grains with a diameter of 40 nm or more on the Si3N4 substrate and the number of organic residues (such as pad debris and polymers) with a diameter of 70 nm or more on the Poly-Si substrate, should preferably be as small as possible. For example, the total number of residues, which is the sum of the number of abrasive grains with a diameter of 40 nm or more on the Si3N4 substrate and the number of organic residues with a diameter of 70 nm or more on the Poly-Si substrate, is acceptable if it is 1,000 or less, preferably 600 or less, more preferably 500 or less, even more preferably 300 or less, particularly preferably 200 or less, and most preferably 150 or less.

[0160] [Evaluation 2: Measurement of water contact angle (wettability)] The water contact angle was measured on Si3N4 substrates after rinsing and polishing using the post-CMP cleaning compositions A1-A14 and B1-B6 prepared in Examples 1-14 and Comparative Examples 1-6 described above.

[0161] Each of the substrates (Poly-Si substrates) used in the above section [Preparation of polished objects] was cut into 60 mm squares to prepare test substrates. Subsequently, polishing was performed on each of them in the same manner as described in the above section [Preparation of polished objects] to obtain polished objects. After that, the polished objects were mounted on a polishing platen in the polishing apparatus described below, and rinse polishing was performed using post-CMP cleaning compositions A1-A14 and B1-B6 prepared in Examples 1-14 and Comparative Examples 1-6 under the following conditions.

[0162] <Rinse polishing apparatus and rinse polishing conditions (for wettability evaluation)> Polishing equipment: Lapping machine EJ-380IN-C, manufactured by Nippon Engis Co., Ltd. Polishing pad: Foamed polyurethane pad H800, manufactured by Fuji Spinning Holdings Co., Ltd. Conditioner (dresser): Nylon brush (made by 3M) Polishing pressure: 1.0 psi Polishing plate rotation speed: 60 rpm Head rotation speed: 60 rpm Supply of post-CMP cleaning composition: flow-through Post-CMP cleaning composition supply rate: 100 mL / min Polishing time: 60 seconds.

[0163] As described above, after the rinse polishing process, surface moisture was removed using an air shower without any post-washing treatment to obtain a polished object that had been rinsed and polished. Subsequently, the water contact angle was measured using the θ / 2 method. A contact angle evaluation device DMo-501 manufactured by Kyowa Interface Science Co., Ltd. was used for the measurement. The results are shown in Tables 1 and 2 below.

[0164] [Evaluation 3: Measurement of Zeta Potential] The zeta potential of Si3N4 substrates during rinse polishing was measured using post-CMP cleaning compositions A1-A14 and B1-B6 prepared in Examples 1-14 and Comparative Examples 1-6 described above.

[0165] In the section above, "Preparation of Polished Objects," each substrate (Si3N4 substrate) used was cut into 30 mm squares to prepare test substrates. Subsequently, polishing was performed in the same manner as described in the section above, "Preparation of Polished Objects," to obtain polished objects for measurement. Then, these objects were placed in a solid zeta potential measuring instrument, SurPASS3 (zeta potential meter), manufactured by Anton Paar Japan Co., Ltd. Next, the post-CMP cleaning compositions A1-A14 and B1-B6 prepared in Examples 1-14 and Comparative Examples 1-6 were passed through the objects, and the zeta potential (mV) of each object was measured. This value was taken as the zeta potential of each wafer during rinse polishing. The results are shown in Tables 1 and 2 below.

[0166] [Table 1]

[0167] [Table 2]

[0168] As is clear from Tables 1 and 2 above, it was found that the post-CMP cleaning compositions A1 to A14 of Examples 1 to 14 can reduce the amount of residue on the surface of polished objects containing silicon-based materials compared to the post-CMP cleaning compositions B1 to B6 of Comparative Examples 1 to 6.

Claims

1. A post-chemical mechanical polishing and cleaning composition comprising an anionic polymer containing a sulfonic acid group and a nitrogen-containing nonionic polymer with a weight-average molecular weight of 2,000 to 20,000.

2. The post-chemical mechanical polishing composition according to claim 1, wherein the nitrogen-containing nonionic polymer is contained in an amount of 10 ppm by mass or more and 1% by mass or less based on the total mass of the post-chemical mechanical polishing composition.

3. The post-chemical mechanical polishing and cleaning composition according to claim 1 or 2, wherein the anionic polymer containing the sulfonic acid group is contained in an amount of 0.1 ppm by mass or more and 1000 ppm by mass or less, based on the total mass of the post-chemical mechanical polishing and cleaning composition.

4. A post-chemical mechanical polishing and cleaning composition according to claim 1 or 2, which controls the water contact angle of polysilicon to 5° or more and 40° or less.

5. A post-chemical mechanical polishing and cleaning composition according to claim 1 or 2, which controls the zeta potential of the silicon nitride surface to -50 mV or more and -20 mV or less.

6. A post-chemical mechanical polishing and cleaning composition according to claim 1 or 2, which substantially does not contain abrasive particles.

7. A post-chemical mechanical polishing and cleaning method, comprising surface-treating a polished object containing at least one selected from the group consisting of silicon dioxide, polysilicon, and silicon nitride using the post-chemical mechanical polishing and cleaning composition according to claim 1 or 2, thereby reducing residue on the surface of the polished object.

8. The post-chemical mechanical polishing and cleaning method according to claim 7, which is a rinsing and polishing method or a cleaning method.

9. The polished object to be polished is a polished semiconductor substrate. A polishing step to obtain a polished semiconductor substrate by polishing a pre-polishing semiconductor substrate containing at least one selected from the group consisting of silicon dioxide, polysilicon, and silicon nitride using a polishing composition containing abrasive particles, A post-chemical mechanical polishing and cleaning process for reducing residue on the surface of the polished semiconductor substrate using the post-chemical mechanical polishing and cleaning composition according to claim 1 or 2, A method for manufacturing a semiconductor substrate that includes [the specified component].

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