Substrate manufacturing method and surface treatment method

Abstract

To provide means capable of sufficiently removing residues remaining on the surface of a polished object to be polished having a layer containing a silicon-containing material.SOLUTION: A substrate manufacturing method includes forming a layer containing a water-soluble polymer on the surface of a polished object to be polished having a layer containing a silicon-containing material, and the layer containing the water-soluble polymer has a thickness of 2 nm or more and 22 nm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a substrate and a method for treating a surface of the substrate. [Background technology]

[0002] In recent years, with the trend toward multilayer wiring on the surface of semiconductor substrates, a so-called chemical mechanical polishing (CMP) technique is used to physically polish and flatten the semiconductor substrate when manufacturing devices. CMP is a method for flattening the surface of an object to be polished (piece to be polished) such as a semiconductor substrate by using a polishing composition (slurry) containing abrasive grains such as silica, alumina, ceria, etc., an anticorrosive agent, a surfactant, etc., and the object to be polished (piece to be polished) is a wiring, plug, etc. made of silicon, polysilicon, silicon oxide, silicon nitride, metal, etc.

[0003] After the CMP process, a large amount of impurities (also called "foreign matter" or "defects") remain on the surface of a semiconductor substrate. The impurities include organic matter such as abrasive grains, metals, anticorrosives, and surfactants derived from the polishing composition used in CMP, silicon-containing materials that are the objects to be polished, silicon-containing materials and metals generated by polishing metal wiring, plugs, etc., and organic matter such as pad debris generated from various pads, etc.

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

[0005] As such a cleaning composition, for example, Patent Document 1 discloses a cleaning composition for semiconductor substrates that contains a polycarboxylic acid or a hydroxycarboxylic acid, a sulfonic acid type anionic surfactant, a carboxylate type anionic surfactant, and water, and discloses that this composition can remove foreign matter without corroding the substrate surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2012-74678 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technique of Patent Document 1 has a problem in that foreign matter (residue) cannot be sufficiently removed when cleaning a polished object having a layer containing a silicon-containing material.

[0008] Therefore, an object of the present invention is to provide a means capable of sufficiently removing residues remaining on the surface of a polished object having a layer containing a silicon-containing material. [Means for solving the problem]

[0009] In view of the above problems, the present inventors have conducted intensive research and have found that the above problems can be solved by a method for manufacturing a substrate, the method including forming a layer containing a water-soluble polymer and having a specific thickness range on a surface of a polished object having a layer containing a silicon-containing material, and have completed the present invention.

[0010] That is, the present invention is a method for manufacturing a substrate, which includes forming a layer containing a water-soluble polymer on a surface of a polished object having a layer containing a silicon-containing material, and the thickness of the layer containing a water-soluble polymer is 2 nm or more and 22 nm or less. Effect of the Invention

[0011] According to the present invention, a means can be provided that can sufficiently remove residues remaining on the surface of a polished object having a layer containing a silicon-containing material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention is a method for manufacturing a substrate, comprising forming a layer containing a water-soluble polymer on a surface of a polished object having a layer containing a silicon-containing material, the layer containing a water-soluble polymer having a thickness of 2 nm to 22 nm. According to the manufacturing method of the present invention, residues remaining on the surface of the polished object having a layer containing a silicon-containing material can be sufficiently removed.

[0013] The present inventors speculate that the mechanism by which such a configuration can remove residues on the surface of a polished object is as follows.

[0014] That is, by forming a layer containing a water-soluble polymer (hereinafter, also simply referred to as a "water-soluble polymer layer") on the surface of the polished object, it is possible to prevent the re-adhesion of residues (contaminants) to the surface of the polished object. Furthermore, by making the thickness of the water-soluble polymer layer 2 nm or more and 22 nm or less, the adhesive force (adhesive force) between the water-soluble polymer on the surface of the polished object and the residues is reduced, making it easier for the residues to detach from the water-soluble polymer on the surface of the polished object, and as a result, it is believed that the residues can be sufficiently removed from the surface of the polished object.

[0015] It should be noted that the above mechanism is based on speculation, and the present invention is not limited to the above mechanism in any way.

[0016] Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to only the following embodiments. In this specification, unless otherwise specified, operations and measurements of physical properties are performed under the conditions of room temperature (20°C or higher and 25°C or lower) and relative humidity of 40% RH or higher and 50% RH or lower.

[0017] <Residue> In this specification, residue refers to foreign matter that adheres to the surface of the polished object.The example of residue is not particularly limited, but can be, for example, organic residue described later, particle residue derived from abrasive grain contained in polishing composition, residue made of components other than particle residue and organic residue, mixture of particle residue and organic residue, and other residues.

[0018] The total number of residues refers to the total number of all residues regardless of type. The total number of residues can be measured using a wafer defect inspection device. Details of the method for measuring the number of residues will be described in the examples below.

[0019] In this specification, the organic residue refers to components of foreign matter adhering to the surface of a polished object, such as organic substances such as organic low molecular weight compounds and high molecular weight compounds, and organic salts.

[0020] Examples of organic residues adhering to the polished object include pad waste generated from the pad used in the polishing process or rinse polishing process described below, or components derived from additives contained in the polishing composition used in the polishing process or the rinse polishing composition used in the rinse polishing process.

[0021] Since organic residues and other foreign matter are significantly different in color and shape, whether or not a foreign matter is an organic residue can be determined by visual observation using, for example, a scanning electron microscope (SEM) SU8000 (manufactured by Hitachi High-Tech Corporation). In addition, whether or not a foreign matter is an organic residue can be determined by elemental analysis using an energy dispersive X-ray analyzer (EDX) attached to the SEM, as necessary. The number of organic residues can be measured using a wafer defect inspection device and SEM or EDX elemental analysis.

[0022] <Polished object> In this specification, the term "polished object" refers to an object that has been polished in a polishing step. The polishing step is not particularly limited, but is preferably a CMP step.

[0023] The polished object according to the present invention has a layer containing a silicon-containing material. Examples of the silicon-containing material include, for example, elemental silicon and silicon compounds. Examples of elemental silicon include, for example, single crystal silicon, polycrystalline silicon (polysilicon), and amorphous silicon. Examples of the silicon compounds include, for example, silicon nitride, silicon oxide, silicon carbide, and silicon germanium. The silicon-containing material also includes low-dielectric constant materials having a relative dielectric constant of 3 or less. In addition, n-type impurity-doped polysilicon and p-type impurity-doped polysilicon are also included in the concept of the polished object according to the present invention. These silicon-containing materials may be used alone or in combination of two or more kinds.

[0024] The polished object according to the present invention may contain other materials as long as it has a layer containing a silicon-containing material. Examples of other materials include carbon and metals. Examples of carbon include crystalline carbon and amorphous carbon. Examples of metals include tungsten, copper, aluminum, hafnium, cobalt, nickel, titanium, tantalum, gold, silver, platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals may be contained in the form of an alloy or a metal compound. These metals may be used alone or in combination of two or more.

[0025] [Substrate manufacturing method] The method for producing a substrate of the present invention includes forming a layer containing a water-soluble polymer and having a thickness of 2 nm to 22 nm on a surface of a polished object having a layer containing a silicon-containing material. The method for forming the layer containing a water-soluble polymer is not particularly limited, but is preferably a method for treating the surface of the polished object using a surface treatment composition containing the water-soluble polymer.

[0026] The above-mentioned surface treatment composition and its production method, as well as a method for treating the surface of a polished object using the surface treatment composition (surface treatment method) will be described below.

[0027] (Surface treatment composition) The surface treatment composition according to the present invention preferably contains a water-soluble polymer. The water-soluble polymer referred to here refers to a water-soluble polymer (single polymer; homopolymer) having the same repeating structural unit, or a water-soluble polymer (copolymer; copolymer) having different repeating structural units, and may typically be a compound having a weight average molecular weight (Mw) of 1000 or more. There is no particular restriction on the type of polymer used as the water-soluble polymer, and any of anionic, cationic, nonionic, and amphoteric polymers can be used. In addition, when the water-soluble polymer is a copolymer, the form of the copolymer may be any of block copolymers, random copolymers, graft copolymers, alternating copolymers, and periodic copolymers.

[0028] Examples of anionic water-soluble polymers include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polymethallyl sulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprene sulfonic acid, polyacrylic acid, and polymethacrylic acid.

[0029] Examples of the cationic water-soluble polymer include polyethyleneimine (PEI), polyvinylamine, polyallylamine, polyvinylpyridine, cationic acrylamide polymers, etc. Specific examples of polyallylamine include polydiallyldimethylammonium chloride, etc.

[0030] Examples of nonionic water-soluble polymers include polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polyvinylpyrrolidone, polyacrylamide, poly(N-vinylacetamide), polyamines, polyvinyl ethers (polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether, etc.), polyalkylene oxides (polyethylene oxide, polypropylene oxide, etc.), polyglycerin, polyethylene glycol, polypropylene glycol, water-soluble cellulose (hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose), and other polysaccharides, alginic acid polyhydric alcohol esters, water-soluble urea resins, dextrin derivatives, casein, etc. In addition to those having such a main chain structure, graft copolymers having a nonionic polymer structure in the side chain can also be suitably used.

[0031] Examples of amphoteric water-soluble polymers include copolymers of a vinyl monomer having an anionic group and a vinyl monomer having a cationic group, and vinyl-based amphoteric polymers having a carboxybetaine group or a sulfobetaine group. Specific examples include acrylic acid / dimethylaminoethyl methacrylic acid copolymers and acrylic acid / diethylaminoethyl methacrylic acid copolymers.

[0032] Furthermore, copolymers of the water-soluble polymers exemplified above can also be used.

[0033] The water-soluble polymer may be used alone or in combination of two or more kinds. In addition, the water-soluble polymer may be a commercially available product or a synthetic product.

[0034] Among these water-soluble polymers, from the viewpoint of facilitating detachment from the substrate after rinse polishing, nonionic water-soluble polymers are preferred, and polyvinyl alcohol, ethylene-vinyl alcohol copolymer, poly-N-vinylacetamide, hydroxyethyl cellulose (HEC), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and ethyl cellulose are more preferred.

[0035] The lower limit of the weight average molecular weight (Mw) of the water-soluble polymer is preferably 1,000 or more, more preferably 1,500 or more, even more preferably 2,000 or more, and even more preferably 5,000 or more. The upper limit of the weight average molecular weight (Mw) of the water-soluble polymer is preferably 1,500,000 or less, more preferably 800,000 or less, even more preferably 500,000 or less, even more preferably 100,000 or less, and particularly preferably 80,000 or less. The weight average molecular weight (Mw) of the water-soluble polymer can be measured as a polyethylene glycol equivalent value using gel permeation chromatography (GPC).

[0036] The content of the water-soluble polymer in the surface treatment composition is appropriately set depending on the type of the water-soluble polymer used, and the lower limit of the content is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, based on the total mass of the surface treatment composition being 100% by mass. The upper limit of the content of the water-soluble polymer in the surface treatment composition is preferably 10% by mass or less, more preferably 5.0% by mass or less, and even more preferably 1.0% by mass or less, based on the total mass of the surface treatment composition being 100% by mass.

[0037] When the surface treatment composition contains two or more water-soluble polymers, the content of the water-soluble polymers refers to the total amount thereof.

[0038] <Surfactant> From the viewpoint of further improving the effects of the present invention, it is preferable that the surface treatment composition according to the present invention further contains a surfactant. The type of the surfactant is not particularly limited, and may be any of nonionic, anionic, cationic, and amphoteric surfactants.

[0039] Examples of nonionic surfactants include alkyl ether types such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether, alkyl phenyl ether types such as polyoxyethylene octylphenyl ether, alkyl ester types such as polyoxyethylene laurate, alkyl amine types such as polyoxyethylene lauryl amino ether, alkyl amide types such as polyoxyethylene lauric acid amide, polypropylene glycol ether types such as polyoxyethylene polyoxypropylene ether, alkanolamide types such as oleic acid diethanolamide, and allyl phenyl ether types such as polyoxyalkylene allyl phenyl ether. In addition, propylene glycol, diethylene glycol, monoethanolamine, alcohol ethoxylate, alkylphenol ethoxylate, tertiary acetylene glycol, alkanolamide, etc. can also be used as nonionic surfactants.

[0040] Examples of anionic surfactants include carboxylic acid types such as sodium myristate, sodium palmitate, sodium stearate, sodium laurate, and potassium laurate; sulfate types such as sodium octyl sulfonate; phosphate types such as lauryl phosphoric acid and sodium lauryl phosphate; and sulfonic acid types such as sodium dioctyl sulfosuccinate and sodium dodecylbenzenesulfonate.

[0041] Examples of cationic surfactants include amines such as laurylamine hydrochloride; quaternary ammonium salts such as polyethoxyamine and lauryltrimethylammonium chloride; and pyridinium salts such as laurylpyridinium chloride.

[0042] Examples of amphoteric surfactants include lecithin, alkylamine oxide, alkylbetaines such as N-alkyl-N,N-dimethylammonium betaine, and sulfobetaines.

[0043] The surfactant may be used alone or in combination of two or more kinds. In addition, the surfactant may be a commercially available product or a synthetic product.

[0044] Among these surfactants, nonionic or anionic surfactants are preferred, and nonionic surfactants are more preferred from the viewpoint of facilitating desorption from the substrate after rinse polishing.

[0045] When the surface treatment composition contains a surfactant, the lower limit of the surfactant content is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, based on 100% by mass of the total mass of the surface treatment composition. The upper limit of the water-soluble polymer content in the surface treatment composition is preferably 5.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on 100% by mass of the total mass of the surface treatment composition.

[0046] When the surface treatment composition contains two or more surfactants, the content of the surfactants refers to the total amount of these surfactants.

[0047] <Solvent> The surface treatment composition according to the present invention may contain a solvent. The solvent has the function of dispersing or dissolving each component. The solvent preferably contains water, and more preferably contains only water. The solvent may also be a mixed solvent of water and an organic solvent for dispersing or dissolving each component. In this case, examples of the organic solvent used include acetone, acetonitrile, ethanol, methanol, isopropanol, glycerin, ethylene glycol, propylene glycol, and the like, which are organic solvents miscible with water. These organic solvents may also be used without mixing with water, and then mixed with water after dispersing or dissolving each component. These organic solvents may be used alone or in combination of two or more.

[0048] The water content in the surface treatment composition is not particularly limited, but is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 97% by mass or more, and may be, for example, 99% by mass or more. When the water content in the surface treatment composition is within the above range, the effects of the present invention tend to be more pronounced.

[0049] The water is preferably water that contains as little residue as possible from the viewpoint of preventing contamination of the polished object and inhibition of the action of other components. For example, water with a total transition metal ion content of 100 ppb or less is preferable. Here, the purity of the water can be increased by, for example, removing residual ions using an ion exchange resin, removing foreign matter using a filter, distillation, or other operations. Specifically, for example, deionized water (ion-exchanged water), pure water, ultrapure water, distilled water, etc. are preferably used.

[0050] <Other additives> The surface treatment composition according to the present invention may contain other additives at an arbitrary ratio within a range that does not inhibit the effects of the present invention. However, components other than the essential components of the surface treatment composition according to the present invention may cause residues, so it is desirable to contain them as little as possible, and thus the content is preferably as small as possible. Examples of other additives are not particularly limited, and include, for example, abrasive grains, preservatives, reducing agents, oxidizing agents, and the like.

[0051] <pH and pH adjuster> The lower limit value of the pH of the surface treatment composition according to the present invention is not particularly limited, but is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, even more preferably 4 or more, and particularly preferably 5 or more. Also, the upper limit value of the pH is not particularly limited, but is preferably 12 or less, more preferably 11 or less, still more preferably 10 or less, even more preferably 9 or less, particularly preferably 8 or less, most preferably 7 or less, and may be, for example, 6 or less. Within this range, the possibility of deteriorating consumable members such as polishing devices and contacting polishing pads is further reduced, and the possibility of the generation of residues and scratches due to the products generated by the deterioration is also further reduced. The pH value of the surface treatment composition can be confirmed by a pH meter (manufactured by Horiba, Ltd., product name: LAQUA (registered trademark)).

[0052] The pH value of the surface treatment composition can be adjusted with a pH adjuster.

[0053] The pH adjuster is not particularly limited, and known pH adjusters used in the field of surface treatment compositions can be used. Among these, it is preferable to use known acids, bases, or salts thereof. Examples of pH adjusters include 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, mellitic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, Examples of suitable acids include carboxylic acids such as adipic acid, fumaric acid, maleic acid, aconitic acid, amino acids, and anthranilic acid, and organic acids such as sulfonic acids and organic phosphonic acids; inorganic acids such as nitric acid, carbonic acid, hydrochloric acid, phosphoric acid, hypophosphorous acid, phosphorous acid, phosphonic acid, boric acid, hydrofluoric acid, orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, metaphosphoric acid, and hexametaphosphoric acid; hydroxides of alkali metals such as potassium hydroxide (KOH); hydroxides of Group 2 elements; ammonia (ammonium hydroxide); and organic bases such as quaternary ammonium hydroxide compounds.

[0054] The pH adjuster may be a synthetic product or a commercially available product, and these pH adjusters may be used alone or in combination of two or more kinds.

[0055] The content of the pH adjuster in the surface treatment composition may be appropriately selected so as to give a desired pH value to the surface treatment composition.

[0056] (Method of manufacturing surface treatment composition) The method for producing the surface treatment composition according to the present invention preferably includes mixing the water-soluble polymer according to the present invention, a solvent, and other components as necessary. For example, the surface treatment composition according to the present invention can be obtained by stirring and mixing the water-soluble polymer according to the present invention, a solvent, and other components as necessary. The temperature at which each component is mixed is not particularly limited, but is preferably 10°C or higher and 40°C or lower, and may be heated to increase the dissolution rate. The mixing time is also not particularly limited.

[0057] [Surface treatment method] As described above, the method for manufacturing a substrate of the present invention includes forming a layer containing a water-soluble polymer having a thickness of 2 nm to 22 nm on the surface of a polished object having a layer containing a silicon-containing material. The method for forming the layer containing a water-soluble polymer is not particularly limited, but is preferably a surface treatment method for treating the surface of a polished object using a surface treatment composition containing the water-soluble polymer. Therefore, according to another aspect of the present invention, a surface treatment method is provided, which includes treating the surface of a polished object having a layer containing a silicon-containing material using a surface treatment composition containing a water-soluble polymer, and forming a layer containing the water-soluble polymer on the surface of the polished object having a layer containing a silicon-containing material, and the thickness of the layer containing the water-soluble polymer is 2 nm to 22 nm.

[0058] In this specification, the surface treatment refers to a treatment for removing residues on the surface of a polished object, and represents a treatment for performing cleaning in a broad sense. The surface treatment method according to one embodiment of the present invention is performed by a method in which a surface treatment composition is directly contacted with a polished object. The surface treatment is not particularly limited, but is preferably performed by, for example, a rinse polishing treatment or a cleaning treatment.

[0059] The surface treatment method according to one embodiment of the present invention is preferably a method using a rinse polishing treatment, because this makes it possible to more efficiently obtain a water-soluble polymer layer having a desired thickness.

[0060] In this specification, the rinse polishing process refers to a process performed on a polishing table (platen) on which a polishing pad is attached, in which a layer of a water-soluble polymer is formed on the surface of a polished object by the frictional force (physical action) of the polishing pad and the action of a surface treatment composition, and a process for removing residues on the surface of the polished object. A specific example of the rinse polishing process is a process in which, after a final polishing (finish polishing) is performed on the object to be polished, the polished object is placed on the polishing table (platen) of a polishing device, the polished object is brought into contact with the polishing pad, and the polished object and the polishing pad are slid relative to each other while supplying a surface treatment composition to the contacting portion.

[0061] More specifically, the rinse polishing treatment is preferably carried out using a general polishing device that is equipped with a holder for holding the object to be polished, a motor capable of changing the rotation speed, and the like, and has a polishing platen on which a polishing pad (polishing cloth) can be attached. The polishing device may be either a single-sided polishing device or a double-sided polishing device. The polishing pad may be made of general nonwoven fabric, polyurethane, porous fluororesin, and the like, without any particular restrictions. Among them, a more preferred polishing pad is polyurethane. The polishing pad is preferably provided with grooves for collecting the polishing liquid. In addition, when the chemical mechanical polishing and the rinse polishing treatment are carried out using the same polishing device, it is preferable that the polishing device is equipped with a nozzle for discharging the surface treatment composition according to one embodiment of the present invention in addition to a nozzle for discharging the polishing composition.

[0062] The condition of rinse polishing is not particularly limited, and can be appropriately set according to the characteristics of the surface treatment composition and the polished object, but in order to obtain a layer containing water-soluble polymer with a desired thickness of 2 nm or more and 22 nm or less, the polishing pressure (polishing load) during rinse polishing is important.In general, if the polishing pressure (polishing load) during rinse polishing is high, the thickness of the water-soluble polymer layer becomes thin, and if the polishing pressure (polishing load) during rinse polishing is low, the thickness of the water-soluble polymer layer becomes thick.

[0063] The lower limit of the polishing pressure (polishing load) during rinse polishing is preferably more than 0.2 psi (1.38 kPa), more preferably 0.3 psi (2.07 kPa) or more, even more preferably 0.4 psi (2.76 kPa) or more, even more preferably 0.5 psi (3.45 kPa) or more, even more preferably 0.7 psi (4.83 kPa) or more, and particularly preferably 1 psi (6.9 kPa) or more. The upper limit of the polishing pressure (polishing load) is preferably less than 5 psi (34.8 kPa), more preferably 4.5 psi (30.1 kPa) or less, even more preferably 4.0 psi (26.6 kPa) or less, even more preferably 3.5 psi (24.1 kPa) or less, and particularly preferably 3.0 psi (20.9 kPa) or less. That is, the polishing pressure (polishing load) during rinse polishing is preferably more than 0.2 psi (1.38 kpa) and less than 5 psi (34.8 kpa), more preferably 0.3 psi (2.07 kpa) or more and 4.5 psi (30.1 kpa) or less, even more preferably 0.4 psi (2.76 kpa) or more and 4.0 psi (26.6 kpa) or less, even more preferably 0.5 psi (3.45 kPa) or more and 3.5 psi (24.1 kPa) or less, particularly preferably 0.7 psi (4.83 kPa) or more and 3.5 psi (24.1 kPa) or less, and most preferably 1 psi (6.9 kPa) or more and 3.0 psi (20.9 kPa) or less. When the water-soluble polymer is PNVA, the polishing pressure (polishing load) during rinse polishing is particularly preferably 1 psi (6.9 kPa) or more and 2 psi (13.8 kPa) or less. If the polishing pressure (polishing load) during rinse polishing is within this range, it becomes easy to form a water-soluble polymer layer having a desired thickness, and residues can be removed efficiently.

[0064] The polishing time during rinse polishing may be appropriately set so as to obtain a water-soluble polymer layer having a desired thickness, and is not particularly limited, but is generally preferably 5 seconds or more, more preferably 10 seconds or more, even more preferably 15 seconds or more, and even more preferably 20 seconds or more. In addition, the polishing time during rinse polishing is preferably 180 seconds or less, more preferably 150 seconds or less, even more preferably 120 seconds or less, and even more preferably 100 seconds or less, from the viewpoint of efficiently removing residues.

[0065] The rotation speed of the platen is not particularly limited and may be appropriately set so as to obtain a water-soluble polymer layer having a desired thickness. Generally, the rotation speed is 10 rpm (0.17 s -1 ) or more 500rpm (8.3s -1 ) or less, and -1 ) or more than 300 rpm (5 s -1 ) or less, and 30 rpm (0.5 s -1 ) or more 200rpm(3.3s -1 ) or less is even more preferable.

[0066] The method of supplying the surface treatment composition is not particularly limited, and a method of continuously supplying the composition (flowing) using a pump or the like may be adopted. The supply amount of the surface treatment composition (flow rate of the surface treatment composition) is not particularly limited as long as the entire polished object is covered with the composition, but is generally preferably 100 mL / min or more and 5000 mL / min or less.

[0067] The surface treatment method may be a method using a cleaning treatment, so long as a layer containing a water-soluble polymer having a thickness of 2 nm to 22 nm can be obtained. In this specification, the cleaning treatment refers to a treatment performed in a state in which the polished object is removed from the polishing table (platen), and the residue on the surface of the polished object is removed mainly by the chemical action of the surface treatment composition. A specific example of the cleaning treatment is a treatment in which the polished object is removed from the polishing table (platen) after the final polishing (finish polishing) of the object to be polished, or after the final polishing followed by a rinse polishing treatment, and the polished object is brought into contact with the surface treatment composition. In the contact state between the surface treatment composition and the polished object to be polished, a means for applying a frictional force (physical action) to the surface of the polished object to be polished may be further used.

[0068] The cleaning method, cleaning device, and cleaning conditions are not particularly limited, and known methods, devices, conditions, etc. can be appropriately used. The cleaning method is not particularly limited, and examples thereof include a method of immersing a polished object in a surface treatment composition and performing ultrasonic treatment as necessary, and a method of contacting a cleaning brush with the polished object while holding the polished object, and scrubbing the surface of the polished object with the brush while supplying the surface treatment composition to the contact area.

[0069] Before or after the step of carrying out the surface treatment method according to one embodiment of the present invention, washing with water may be performed, or both. After that, water droplets adhering to the surface of the polished object may be removed by a spin dryer, an air blower, or the like, and the surface may be dried.

[0070] <Thickness of water-soluble polymer layer> In the substrate manufacturing method and surface treatment method according to the present invention, the thickness of the water-soluble polymer layer formed on the ground object is 2 nm or more and 22 nm or less. If the thickness is less than 2 nm, the residue is likely to adhere to the ground object, making it difficult to remove the residue. On the other hand, if the thickness exceeds 22 nm, the viscoelasticity of the water-soluble polymer layer increases, and the entanglement between the residue and the water-soluble polymer increases, making it difficult to remove the residue. The lower limit of the thickness of the water-soluble polymer layer is preferably 3 nm or more, more preferably 5 nm or more. The upper limit of the thickness of the water-soluble polymer layer is preferably 20 nm or less, more preferably 15 nm or less.

[0071] In the present invention, the thickness of the water-soluble polymer layer is measured by spectroscopic ellipsometry. The method for measuring the thickness of the water-soluble polymer layer is described in detail in the Examples.

[0072] <Adhesive strength> The water-soluble polymer layer having the above thickness has a small adhesive force with the residue, facilitating the detachment of the residue. The adhesive force between the residue and the water-soluble polymer layer can be measured by the adhesive strength of the water-soluble polymer layer to the SiO2 probe when measured by an atomic force microscope (AFM) using a SiO2 probe. The SiO2 probe is made of the same compound as silica abrasive grains that are generally used in polishing, and it can be said that the smaller the adhesive strength of the water-soluble polymer layer to the SiO2 probe, the easier it is to remove the residue from the polished object. That is, according to a preferred embodiment of the present invention, the adhesive strength of the layer containing the water-soluble polymer to the SiO2 probe when measured by an atomic force microscope using a SiO2 probe is 5.0 nN or less. The adhesive strength also tends to be proportional to the tip curvature radius of the SiO2 probe.

[0073] The adhesive strength is preferably 5.0 nN or less, more preferably 4.0 nN or less, even more preferably 3.0 nN or less, even more preferably 2.0 nN or less, particularly preferably 1.0 nN or less, and most preferably 0.5 nN or less, and may be, for example, less than 0.45 nN, typically 0.3 nN or less, or 0.15 nN or less. The lower limit of the adhesive strength is preferably 0 nN or more, more preferably 0.001 nN or more, and even more preferably 0.01 nN or more.

[0074] The details of the method for measuring the adhesive strength are as described in the Examples.

[0075] [Method of manufacturing semiconductor substrate] As described above, the method for manufacturing a substrate according to one embodiment of the present invention includes forming a layer containing a water-soluble polymer having a thickness of 2 nm to 22 nm on a surface of a ground object having a layer containing a silicon-containing material. In particular, the method for manufacturing a substrate according to one embodiment of the present invention is preferably applied when the ground object is a ground semiconductor substrate. That is, according to another preferred embodiment of the present invention, there is also provided a method for manufacturing a semiconductor substrate, in which the ground object is a ground semiconductor substrate, and the method includes forming a layer containing a water-soluble polymer on the surface of the ground semiconductor substrate by the above-mentioned surface treatment method, and the layer containing a water-soluble polymer has a thickness of 2 nm to 22 nm.

[0076] Details of the semiconductor substrate to which this manufacturing method is applied are as described above for the polished object to be surface-treated with the surface treatment composition.

[0077] In addition, the method for producing a substrate is not particularly limited as long as it includes a step (surface treatment step) of surface-treating the surface of a ground object (preferably a ground semiconductor substrate) with a surface treatment composition according to one embodiment of the present invention. For example, such a production method includes a method having a polishing step for forming a ground object and a surface treatment step. These steps will be described below.

[0078] [Polishing process] In the method for manufacturing a substrate according to a preferred embodiment of the present invention, the step of obtaining a polished object is a step of polishing an object (preferably a semiconductor substrate) to form a polished object.

[0079] The polishing step is not particularly limited as long as it is a step of polishing an object to be polished (preferably a semiconductor substrate), but is preferably a chemical mechanical polishing (CMP) step. The polishing step may be a polishing step consisting of a single step or a polishing step consisting of multiple steps. Examples of the polishing step consisting of multiple steps include a step of performing a finish polishing step after a preliminary polishing step (rough polishing step), and a step of performing one or more secondary polishing steps after a primary polishing step, and then performing a finish polishing step. The surface treatment step using the surface treatment composition according to the present invention is preferably performed after the above-mentioned finish polishing step.

[0080] The polishing composition may be a known polishing composition depending on the characteristics of the semiconductor substrate, and may preferably be, for example, a composition containing abrasive grains, a dispersion medium, and an acid. Specific examples of such polishing compositions include a polishing composition containing colloidal silica, water, and maleic acid.

[0081] The polishing device may be a general polishing device that is equipped with a holder for holding the object to be polished, a motor capable of changing the rotation speed, and a polishing platen to which a polishing pad (polishing cloth) can be attached. Either a single-sided polishing device or a double-sided polishing device may be used.

[0082] The polishing pad may be made of any material, including general nonwoven fabric, polyurethane, and porous fluororesin, without any particular limitations. Among them, polyurethane is more preferred. The polishing pad is preferably provided with grooves for collecting the polishing liquid.

[0083] There are no particular limitations on the polishing conditions. For example, the rotation speed of the polishing plate and the head (carrier) are 10 rpm (0.17 s -1 ) or more 100rpm(1.67s -1 ) or less, and the pressure applied to the object to be polished (polishing pressure) is preferably 0.5 psi (3.45 kPa) or more and 10 psi (68.9 kPa) or less. The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying the composition with a pump or the like (flowing) is adopted. There is no limit to the amount of supply, but it is preferable that the surface of the polishing pad is always covered with the polishing composition, and the supply rate is preferably 10 mL / min to 5000 mL / min, more preferably 20 mL / min to 4000 mL / min, even more preferably 30 mL / min to 3000 mL / min, even more preferably 35 mL / min to 2000 mL / min, particularly preferably 40 mL / min to 1000 mL / min, and most preferably 45 mL / min to 500 mL / min, and may be, for example, 50 mL / min to 300 mL / min, typically 55 mL / min to 150 mL / min. The polishing time is not particularly limited, but for the step using the polishing composition, it is preferably from 5 seconds to 180 seconds, more preferably from 10 seconds to 150 seconds, and even more preferably from 15 seconds to 120 seconds.

[0084] [Surface treatment process] The surface treatment step refers to a step including forming a layer containing a water-soluble polymer on the surface of a polished object using the surface treatment composition of the present invention and reducing residues. In the manufacturing method of a semiconductor substrate, after the rinse-polishing step, a cleaning step may be performed as a surface treatment step, or only the rinse-polishing step or only the cleaning step may be performed.

[0085] The details of the rinse polishing method and the cleaning method used in the rinse polishing step and the cleaning step are as described above in the explanation of the rinse polishing treatment and the cleaning treatment.

[0086] In the method for manufacturing a substrate according to the present invention, steps other than the polishing step and the surface treatment step can be appropriately selected from steps that can be adopted in known methods for manufacturing semiconductor substrates. EXAMPLES

[0087] 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, "%" and "parts" mean "% by mass" and "parts by mass", respectively. In the following examples, unless otherwise specified, the operations were performed under the conditions of room temperature (25°C) / relative humidity of 40% RH or more and 50% RH or less.

[0088] [Preparation of water-soluble polymers] Poly N-vinylacetamide (PNVA with a weight average molecular weight (Mw) of 50,000, manufactured by Showa Denko K.K.) and polyvinyl alcohol (PVA with a weight average molecular weight (Mw) of 10,000 (saponification degree 99%), manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.) were prepared. The weight average molecular weight of the water-soluble polymer was measured by the following method.

[0089] [Measurement of weight-average molecular weight (Mw) of water-soluble polymers] The weight average molecular weight (Mw) of the water-soluble polymer was measured by gel permeation chromatography (GPC) using the weight average molecular weight (converted into polyethylene glycol). The weight average molecular weight was measured using the following apparatus and conditions: GPC equipment: Shimadzu Corporation Model: Prominence + ELSD detector (ELSD-LTII) Column: VP-ODS (Shimadzu Corporation) Mobile phase A:MeOH B: 1% acetic acid solution Flow rate: 1mL / min Detector: ELSD temp. 40℃, Gain 8, N2GAS 350kPa Oven temperature: 40℃ Injection volume: 40μL.

[0090] [Preparation of surface treatment composition] (Preparation Example 1) Poly-N-vinylacetamide, which is a water-soluble polymer, and water (deionized water) which is a solvent were mixed to prepare surface treatment composition 1. Here, the content of the water-soluble polymer was 0.2 mass% relative to the total amount of surface treatment composition 1, and the pH of surface treatment composition 1 was 5.9.

[0091] (Preparation Example 2) Polyvinyl alcohol, which is a water-soluble polymer, and water (deionized water), which is a solvent, were mixed to prepare surface treatment composition 2. Here, the content of the water-soluble polymer was 0.2 mass% relative to the total amount of surface treatment composition 2, and the pH of surface treatment composition 2 was 4.4.

[0092] [Measurement of pH of surface treatment composition] The pH of the surface treatment composition (liquid temperature: 25° C.) was confirmed using a pH meter (manufactured by Horiba, Ltd., product name: LAQUA (registered trademark)).

[0093] [Preparation of polished object] A polished polysilicon substrate that had been polished by the following chemical mechanical polishing (CMP) process was prepared as a polished object.

[0094] (CMP process) A 12-inch polycrystalline silicon (polysilicon) wafer (manufactured by Advanced Materials Technology Co., Ltd.) was prepared as an object to be polished.

[0095] The polysilicon substrate prepared above was polished using a polishing composition (composition: 4 mass% colloidal silica (average primary particle size 30 nm, average secondary particle size 60 nm), 0.018 mass% aqueous maleic acid solution with a concentration of 30 mass%, solvent: water) under the following conditions: <Polishing equipment and polishing conditions> Polishing equipment: Ebara Corporation FREX300E Polishing pad: Fujibo Holdings Co., Ltd. Polyurethane foam pad H800 Polishing pressure: 2.0 psi (1 psi = 6894.76 Pa, same below) Polishing platen rotation speed: 80 rpm Head rotation speed: 80 rpm Supply of polishing composition: free-flowing Polishing composition supply amount: 200mL / min Polishing time: 30 seconds.

[0096] (Rinse polishing process) Example 1 The polished object obtained by polishing the surface of the object in the CMP step was removed from the polishing table (platen). Next, in the same polishing apparatus, the polished object was mounted on another polishing table (platen), and the surface of the polished object was subjected to a rinse polishing treatment using the surface treatment composition 1 prepared in Preparation Example 1 under the following conditions: <Rinse polishing device and rinse polishing conditions> Polishing equipment: Ebara Corporation FREX300E Polishing pad: Fujibo Holdings Co., Ltd. Polyurethane foam pad H800 Surface treatment composition supply amount: 300 mL / min Rinse polishing time: 10 seconds Rinse polishing pressure: 0.5psi (3.4kPa) Plate rotation speed: 60 rpm.

[0097] (Examples 2 to 20) A rinse polishing process was performed in the same manner as in Example 1, except that the polishing time and polishing pressure were changed as shown in Table 1 below.

[0098] (Examples 21 to 40) A rinse polishing treatment was carried out in the same manner as in Example 1, except that the surface treatment composition 2 prepared in Preparation Example 2 above was used and the polishing time and polishing pressure were changed as shown in Table 2 below.

[0099] (Examples 41 to 42) Dodecylbenzenesulfonic acid was added to the above surface treatment composition 1 so as to give a concentration of 0.05 mass % to prepare surface treatment composition 3. The pH of surface treatment composition 3 was 5.6. Using this surface treatment composition 3, a rinse polishing treatment was performed in the same manner as in Example 1, except that the polishing time and polishing pressure were changed as shown in Table 3 below.

[0100] (Examples 43 to 44) A surface treatment composition 4 was prepared by adding oleic acid diethanolamide to the surface treatment composition 2 so that the concentration was 0.05% by mass. The pH of the surface treatment composition 4 was 5.8. A rinse polishing treatment was carried out in the same manner as in Example 1, except that the polishing time and polishing pressure were changed as shown in Table 3 below, using the surface treatment composition 4.

[0101] (Comparative Examples 1 to 4) Poly-N-vinylacetamide, which is a water-soluble polymer, and water (deionized water) which is a solvent were mixed to prepare surface treatment composition 5. Here, the content of the water-soluble polymer was 0.2 mass% relative to the total amount of surface treatment composition 1, and the pH of surface treatment composition 5 was 5.9.

[0102] Using this surface treatment composition 5, a rinse polishing treatment was carried out in the same manner as in Example 1, except that the polishing time and polishing pressure were changed as shown in Table 3 below.

[0103] Comparative Example 5 A rinse polishing treatment was carried out in the same manner as in Example 10, except that deionized water was used instead of the surface treatment composition 1.

[0104] (Cleaning process) In the above-mentioned rinse polishing step, the polysilicon substrates (hereinafter also referred to as "rinse-polished objects") obtained by rinse-polishing the polished surfaces of the objects were transported from the polishing table (platen) to a cleaning device (cleaner tank portion) attached to the polishing device. Thereafter, the rinse-polished surfaces of the objects were cleaned using water (deionized water) while applying pressure with a polyvinyl alcohol (PVA) sponge, which was a cleaning brush, under the following conditions: <Cleaning equipment and cleaning conditions> Cleaning equipment: Ebara Corporation FREX300E Cleaning brush rotation speed: 100 rpm Polished object rotation speed: 100 rpm Type of cleaning composition: Water (deionized water) Cleaning composition supply rate: 1000mL / min Cleaning time: 60 seconds.

[0105] [evaluation] In measuring the thickness and adhesive strength of the water-soluble polymer layer, a polished object that had been subjected to the rinse-polishing process was prepared.

[0106] (Water-soluble polymer layer thickness measurement) After the rinse-polishing process, the polished object was cut into 20 mm squares and measured by a spectroscopic ellipsometry (Horiba, UVISEL Plus). The measurement was performed by immersing the sample in a glass cell filled with pure water.

[0107] (Adhesion strength measurement) After the rinse-polishing process, the polished object was cut into 10 mm squares, and the adhesive strength between the residue and the water-soluble polymer layer was measured using an atomic force microscope (AFM). The measuring device and conditions are shown below. A force curve was measured in pure water, and the force measured just before the probe jumped out on the return path was taken as the adhesive strength. The smaller the adhesive strength value, the easier it is for the residue to detach: Measuring device: S-image / NanonaviII, manufactured by SII Nano Technology Co., Ltd. Probe: Nanoworld, model qp-scont, tip curvature radius 10nm, material SiO2 Sampling frequency: 1Hz Scan range: -1nm~+200nm.

[0108] (Residue count measurement) The number of residues with a diameter of 65 nm or more remaining on the surface of the polysilicon substrate (cleaned object to be polished) after the above cleaning process was measured using an optical inspection machine, Surfscan (registered trademark) SP5, manufactured by KLA-Tencor Co., Ltd. Note that a 5 mm section around the periphery of the cleaned object to be polished was excluded from the measurement area.

[0109] The evaluation results are shown in Tables 1 to 3 below.

[0110] [Table 1]

[0111] [Table 2]

[0112] [Table 3]

[0113] As is clear from Tables 1 to 3 above, the manufacturing methods of the Examples were found to reduce the amount of residue on the surface of the polished object, as compared with the manufacturing methods of the Comparative Examples. In the cases of Examples 41 to 44, in which a surface treatment composition containing a surfactant was used, it was found that the amount of residue was further reduced.

Claims

1. A method for manufacturing a substrate, comprising forming a layer containing a water-soluble polymer on a surface of a polished object having a layer containing a silicon-containing material, the method comprising: The formation of the layer containing the water-soluble polymer includes subjecting the surface of the polished object to a rinse polishing treatment using a surface treatment composition containing the water-soluble polymer, The polishing pressure during the rinse polishing process is greater than 0.2 psi and less than 5 psi; A method for producing a substrate, wherein the thickness of the layer containing the water-soluble polymer is 2 nm or more and 22 nm or less as measured by the following measurement method: <Method for measuring the thickness of a layer containing a water-soluble polymer> The polished object after the rinse-polishing process is cut into a 20 mm square and measured by spectroscopic ellipsometry while immersing the sample in a glass cell filled with pure water.

2. SiO ２ When measured with an atomic force microscope using a probe, the SiO ２ The method according to claim 1 , wherein the adhesive strength of the layer containing the water-soluble polymer to the probe is 5.0 nN or less.

3. The method according to claim 1 or 2, wherein the water-soluble polymer is a nonionic water-soluble polymer.

4. The method according to any one of claims 1 to 3, wherein the surface treatment composition containing the water-soluble polymer further contains a surfactant.

5. The method according to claim 4, wherein the surfactant is a nonionic surfactant.

6. A surface treatment method comprising: treating a surface of a polished object having a layer containing a silicon-containing material with a surface treatment composition containing a water-soluble polymer, and forming a layer containing the water-soluble polymer on the surface of the polished object having a layer containing a silicon-containing material, the method comprising: The surface treatment is a rinse polishing treatment, The polishing pressure during the rinse polishing process is greater than 0.2 psi and less than 5 psi; A surface treatment method, wherein the thickness of the layer containing the water-soluble polymer is 2 nm or more and 22 nm or less, as measured by the following measurement method: <Method for measuring the thickness of a layer containing a water-soluble polymer> The polished object after the rinse-polishing process is cut into a 20 mm square and measured by spectroscopic ellipsometry while immersing the sample in a glass cell filled with pure water.

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