WO2013105603A1 - Barrier layer forming composition, barrier layer, production method for solar cell substrate, and production method for solar cell element - Google Patents

Barrier layer forming composition, barrier layer, production method for solar cell substrate, and production method for solar cell element Download PDF

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WO2013105603A1
WO2013105603A1 PCT/JP2013/050306 JP2013050306W WO2013105603A1 WO 2013105603 A1 WO2013105603 A1 WO 2013105603A1 JP 2013050306 W JP2013050306 W JP 2013050306W WO 2013105603 A1 WO2013105603 A1 WO 2013105603A1
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barrier layer
forming
composition
metal
mass
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PCT/JP2013/050306
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French (fr)
Japanese (ja)
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明博 織田
吉田　誠人
野尻　剛
倉田　靖
岩室　光則
茂 野部
悠平 岡田
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日立化成株式会社
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Priority to JP2013518614A priority Critical patent/JP5339011B1/en
Publication of WO2013105603A1 publication Critical patent/WO2013105603A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/22—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
    • H01L21/225—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities using diffusion into or out of a solid from or into a solid phase, e.g. a doped oxide layer
    • H01L21/2251—Diffusion into or out of group IV semiconductors
    • H01L21/2254—Diffusion into or out of group IV semiconductors from or through or into an applied layer, e.g. photoresist, nitrides
    • H01L21/2255—Diffusion into or out of group IV semiconductors from or through or into an applied layer, e.g. photoresist, nitrides the applied layer comprising oxides only, e.g. P2O5, PSG, H3BO3, doped oxides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention relates to a barrier layer forming composition, a barrier layer, a method for manufacturing a solar cell substrate, and a method for manufacturing a solar cell element.
  • a p-type silicon substrate having a texture structure formed on the light receiving surface (surface) is prepared so as to promote the light confinement effect, and then a mixed gas of phosphorus oxychloride (POCl 3 ), nitrogen and oxygen.
  • a tens of minutes of treatment is performed at 800 ° C. to 900 ° C. in an atmosphere to form an n-type diffusion layer uniformly on the surface of the p-type silicon substrate.
  • an electrode paste such as silver (Ag) on the light receiving surface and an electrode paste such as aluminum (Al) on the back side
  • the solar cell element was obtained by firing.
  • a method of forming such a back electrode type solar cell will be described.
  • a barrier layer is formed on the entire light receiving surface and back surface of the n-type silicon substrate.
  • the barrier layer has a function of suppressing the diffusion of the dopant into the silicon substrate.
  • a part of the barrier layer on the back surface of the silicon substrate is removed to form an opening.
  • a p + -type diffusion layer is formed only in a region corresponding to the opening.
  • a barrier layer is formed again on the entire back surface of the silicon substrate.
  • a part of the barrier layer in a region different from the region where the p + -type diffusion layer is formed is removed to form an opening, and an n-type dopant is diffused from the opening to the back surface of the silicon substrate.
  • a + type diffusion layer is formed.
  • a p + -type diffusion layer and an n + -type diffusion layer are formed on the back surface.
  • a back electrode type solar cell is completed by forming a texture structure, an antireflection film, a passivation film, an electrode, and the like.
  • barrier layer As the barrier layer, a method using an oxide film formed on the surface of a silicon substrate by a thermal oxidation method has been proposed (see, for example, JP-A-2002-329880). On the other hand, a method for forming a barrier layer using a masking paste containing a SiO 2 precursor has also been proposed (see, for example, Japanese Patent Application Laid-Open No. 2007-49079).
  • the method of generating an oxide film on the surface of a silicon substrate by the thermal oxidation method described in Japanese Patent Application Laid-Open No. 2002-329880 described above has a problem that the manufacturing cost is high because the throughput is long.
  • it is intended to physically prevent diffusion of a donor element or an acceptor element, and further a barrier made of SiO 2. Since it is difficult to form a dense film in the layer, pinholes are easily formed. Therefore, it is difficult to sufficiently prevent diffusion of the dopant into the substrate.
  • the present invention has been made in view of the above conventional problems, and a barrier layer forming composition capable of sufficiently preventing the diffusion of a donor element or an acceptor element into a semiconductor substrate and suppressing the surface roughness of the semiconductor substrate. It is an object to provide an object, a barrier layer formed using the same, a method for manufacturing a solar cell substrate using the same, and a method for manufacturing a solar cell element.
  • ⁇ 1> Contains an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, and one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils.
  • a composition for forming a barrier layer containing an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, and one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils.
  • composition for forming a barrier layer according to ⁇ 1> wherein the specific compound includes one or more selected from the group consisting of silicon alkoxide, methyl silicate oligomer, and ethyl silicate oligomer.
  • ⁇ 3> The barrier layer according to ⁇ 1> or ⁇ 2>, wherein the specific compound includes silicon alkoxide, and the silicon alkoxide includes one or more selected from the group consisting of tetramethoxysilane and tetraethoxysilane. Forming composition.
  • composition for forming a barrier layer according to any one of ⁇ 1> to ⁇ 3>, wherein the content of the specific compound in the nonvolatile component is 0.5% by mass or more and 50% by mass or less. .
  • the alkaline earth metal or the metal compound containing an alkali metal is selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium, and radium as the metal element.
  • the alkaline earth metal or the metal compound containing an alkali metal is selected from magnesium oxide, calcium oxide, potassium oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, calcium sulfate, calcium nitrate, magnesium hydroxide, and calcium hydroxide.
  • composition for forming a barrier layer according to ⁇ 8> wherein the organic binder includes one or more selected from the group consisting of an acrylic resin, a butyral resin, and a cellulose resin.
  • the dispersion medium contains one or more selected from the group consisting of water, alcohol solvents, ether solvents, glycol monoether solvents, and terpene solvents. 2.
  • ⁇ 11> Any one of the above ⁇ 1> to ⁇ 10>, wherein a content ratio of the alkaline earth metal or the metal compound containing the alkali metal in the nonvolatile component is 0.5% by mass or more and less than 100% by mass 2.
  • composition for forming a barrier layer according to any one of ⁇ 1> to ⁇ 11>, wherein the viscosity at 25 ° C. is 0.5 Pa ⁇ s or more and 400 Pa ⁇ s or less.
  • ⁇ 13> The barrier layer according to ⁇ 1> to ⁇ 12>, wherein a content of the alkaline earth metal or the metal compound containing the alkali metal in the nonvolatile component is 10% by mass to 55% by mass. Forming composition.
  • composition for forming a barrier layer according to any one of ⁇ 1> to ⁇ 13>, wherein the viscosity at 25 ° C. is 40 Pa ⁇ s or more and 200 Pa ⁇ s or less.
  • the alkaline earth metal or the metal compound containing an alkali metal includes one or more selected from the group consisting of calcium oxide and calcium carbonate
  • a barrier layer which is a dried body of the composition for forming a barrier layer according to any one of ⁇ 1> to ⁇ 17>.
  • ⁇ 20> The method for producing a solar cell substrate according to ⁇ 19>, wherein the method for applying the barrier layer forming composition is a printing method or an inkjet method.
  • a method for producing a solar cell element comprising a step of forming an electrode on a diffusion layer of a solar cell substrate obtained by the production method according to ⁇ 19> or ⁇ 20>.
  • a barrier layer forming composition that can sufficiently prevent the diffusion of a donor element or an acceptor element into a semiconductor substrate and suppress the surface roughness of the semiconductor substrate, a barrier layer formed using the composition, The manufacturing method of the board
  • the composition for forming a barrier layer of the present invention will be described, and then the method for manufacturing a solar cell substrate and the method for manufacturing a solar cell element using the composition for forming a barrier layer will be described.
  • the term “process” is not limited to an independent process, and is included in the term if the purpose of the process is achieved even when it cannot be clearly distinguished from other processes.
  • “ ⁇ ” indicates a range including the numerical values described before and after the values as the minimum value and the maximum value, respectively.
  • the amount of each component in the composition is the sum of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. Means quantity.
  • the donor element or the acceptor element may be referred to as a dopant.
  • the barrier layer in the present invention includes not only the case where the barrier layer is formed on the entire surface when the semiconductor substrate is observed as a plan view, but also the case where the barrier layer is formed on a part thereof.
  • the composition for forming a barrier layer of the present invention includes an alkaline earth metal or a metal compound containing an alkali metal (hereinafter also referred to as “specific alkali compound”), a dispersion medium, a metal alkoxide, a silicon alkoxide, a silicate oligomer, and a silicone. And one or more specific compounds selected from the group consisting of oils.
  • the composition for forming a barrier layer of the present invention inhibits diffusion of a donor element or an acceptor element, which is a dopant, into a semiconductor substrate.
  • the donor element and the acceptor element are diffused in the region. It can be sufficiently prevented. Therefore, it is possible to selectively form a doping region in the semiconductor substrate. The reason for this can be considered as follows.
  • the specific alkali compound is preferably a basic compound.
  • the specific alkali compound of the basic compound undergoes an acid-base reaction with the doping compound, and this acid-base reaction is highly reactive, thereby more effectively preventing the donor element or acceptor element from diffusing into the semiconductor substrate. .
  • the specific alkali compound is preferably a metal compound that is thermally stable even at a high temperature of 500 ° C. or higher.
  • the basic metal compound an alkaline earth metal or a metal compound containing an alkali metal is preferable.
  • An alkaline earth metal or a metal compound containing an alkali metal does not act as a carrier recombination center in a semiconductor substrate when it is dissolved in the semiconductor substrate, thereby suppressing the problem of reducing the conversion efficiency of the solar cell substrate. be able to.
  • the barrier layer-forming composition of the present invention contains one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils.
  • the composition for forming a barrier layer containing the specific compound By using the composition for forming a barrier layer containing the specific compound, the erosion of the semiconductor substrate by the specific alkali compound is suppressed in the barrier layer forming step, and the occurrence of surface roughness of the semiconductor substrate can be suppressed.
  • damage to the silicon substrate, which is a semiconductor substrate can be suppressed, and a decrease in power generation characteristics of a solar cell element using the semiconductor substrate can be suppressed.
  • the composition for forming a barrier layer of the present invention contains an alkaline earth metal or a metal compound containing an alkali metal.
  • the alkaline earth metal or the metal compound containing the alkali metal may be liquid or solid at room temperature (about 20 ° C.). From the viewpoint that it is necessary to be chemically stable even at a high temperature in order to maintain a sufficient barrier layer performance even at a high temperature, it is preferably a solid at a high temperature (for example, 500 ° C. or higher) at which heat is diffused.
  • the alkaline earth metal or the metal compound containing an alkali metal includes an alkaline earth metal or a metal oxide containing an alkali metal, and an alkaline earth metal or a metal salt containing an alkali metal. .
  • the metal compound containing an alkaline earth metal or an alkali metal is not particularly limited, and is preferably a material that changes to a basic compound at a high temperature of 700 ° C. or higher at which a donor element or an acceptor element is thermally diffused.
  • the metal compound contains at least one selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium as a metal element. It is more preferable that it contains at least one selected from the group consisting of magnesium, calcium, barium, potassium and sodium, and more preferably contains at least one selected from the group consisting of magnesium, calcium and potassium.
  • the viewpoint of low toxicity and availability it is particularly preferable to contain one or more selected from the group consisting of magnesium and calcium.
  • the group consisting of metal oxides, metal carbonates, metal nitrates, metal sulfates and metal hydroxides containing one or more selected from the group consisting of these metal elements It is preferable that it is 1 or more types selected, and it is more preferable that it is 1 or more types selected from the group which consists of a metal oxide, a metal carbonate, and a metal hydroxide.
  • metal oxides such as sodium oxide, potassium oxide, lithium oxide, calcium oxide, magnesium oxide, rubidium oxide, cesium oxide, beryllium oxide, strontium oxide, barium oxide, radium oxide, and complex oxides thereof; sodium hydroxide, Metal hydroxides such as potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, beryllium hydroxide, strontium hydroxide, barium hydroxide, radium hydroxide; sodium carbonate, carbonic acid Metal carbonates such as potassium, lithium carbonate, calcium carbonate, magnesium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, strontium carbonate, barium carbonate, radium carbonate; sodium nitrate, potassium nitrate, lithium nitrate, calcium nitrate Metal nitrates such as magnesium nitrate, rubidium nitrate, cesium nitrate, beryllium nitrate, strontium oxide,
  • sodium carbonate, sodium oxide, potassium carbonate, potassium oxide, calcium carbonate, calcium hydroxide, calcium oxide, magnesium carbonate, magnesium hydroxide, magnesium sulfate, calcium sulfate It is preferable to use at least one selected from calcium nitrate and magnesium oxide, magnesium oxide, calcium oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, calcium sulfate, calcium nitrate, potassium oxide, magnesium hydroxide, calcium stearate, And at least one selected from the group consisting of calcium hydroxide, calcium carbonate, calcium oxide, potassium oxide, calcium hydroxide, magnesium carbonate, and magnesium oxide. More preferably to use at least one selected from Neshiumu, calcium carbonate, it is particularly preferable to use at least one selected from calcium oxide.
  • the base strength of an alkaline earth metal or a metal compound containing an alkali metal or a compound obtained by heat-treating it in air or in an inert atmosphere at 800 ° C. or higher is preferably 12.2 or higher, and 17.2 or higher. It is more preferable that it is 26.5 or more.
  • 800 ° C. or higher is a temperature that can be adopted as a temperature for actually diffusing a donor element or an acceptor element and reflects an actual use environment.
  • the surface area and particle diameter of an alkaline earth metal or a metal compound containing an alkali metal are the same, the higher the base strength, the more the barrier ability of the barrier layer formed using it, i.e., the diffusion of donor and acceptor elements. Increases ability to inhibit.
  • the base strength here is an acidity function H ⁇ using a Hammett indicator and can be measured by a change in color when the indicator is adsorbed. Specifically, when 2,4,6-trinitroaniline is used as an indicator, H ⁇ is 12.2 or more when yellow changes to red-orange, and when 2,4-dinitroaniline is used, it changes from yellow to purple. When H ⁇ is 15.0 or higher and 4-chloro-2-nitroaniline is used, the color changes from yellow to orange. When H ⁇ is 18.4 or higher and 4-chloroaniline is used, the color changes from yellow to pink. In this case, H ⁇ is 26.5 or more.
  • the surface of the alkaline earth metal or the metal compound containing the alkali metal may be surface-treated with a metal oxide such as silicon oxide, zirconium oxide, zinc oxide, titanium oxide, or aluminum oxide.
  • a metal oxide such as silicon oxide, zirconium oxide, zinc oxide, titanium oxide, or aluminum oxide.
  • the particle diameter of the particles is preferably 30 ⁇ m or less. It is more preferably from 01 ⁇ m to 30 ⁇ m, further preferably from 0.02 ⁇ m to 10 ⁇ m, and particularly preferably from 0.03 ⁇ m to 5 ⁇ m.
  • the particle diameter is 30 ⁇ m or less, the donor element or the acceptor element is easily diffused (doped) into a desired region of the semiconductor substrate.
  • the alkaline earth metal or the metal compound containing an alkali metal may be dissolved in the dispersion medium.
  • the particle diameter represents a volume average particle diameter, and can be measured with a laser scattering diffraction particle size distribution measuring apparatus or the like.
  • the volume average particle diameter can be calculated based on the Mie scattering theory by detecting the relationship between the scattered light intensity and the angle of the laser light applied to the particles.
  • the method for obtaining particles of a specific alkali compound having a particle size of 30 ⁇ m or less is not particularly limited, and can be obtained by, for example, pulverization.
  • a grinding method a dry grinding method and a wet grinding method can be employed.
  • a jet mill, a vibration mill, a ball mill, or the like can be employed.
  • a wet pulverization method a bead mill, a ball mill or the like can be used.
  • the lifetime of the carriers in the semiconductor substrate may be reduced. It is preferable to select a material with little influence.
  • the material of the container and the like that are preferably used during pulverization include alumina and partially stabilized zirconia.
  • a gas phase oxidation method, a hydrolysis method, or the like can be used in addition to the pulverization method.
  • the particles of the specific alkali compound are particles made of a compound other than an alkaline earth metal or a metal compound containing an alkali metal (for example, silicon oxide particles) as a carrier, and an alkaline earth metal or alkali is formed on the surface of the carrier.
  • a material in which a metal compound containing a metal is coated or dispersedly supported may be used.
  • it is possible to increase the effective surface area of the alkaline earth metal or the metal compound containing the alkali metal it is possible to increase the effective surface area of the alkaline earth metal or the metal compound containing the alkali metal, and there is a possibility that the property of inhibiting the diffusion of the donor element or the acceptor element into the semiconductor substrate may be improved. .
  • the carrier is preferably a material having a BET specific surface area of 10 m 2 / g or more, and examples thereof include particles of inorganic materials such as SiO 2 , activated carbon, carbon fiber, and zinc oxide.
  • the shape of the particles of the specific alkali compound is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a scale shape, a block shape, an oval shape, a plate shape, a sea gall shape, a porous sphere shape, and a rod shape.
  • the shape of the particles can be confirmed by an electron microscope or the like.
  • the content of the alkaline earth metal or the metal compound containing the alkali metal in the composition for forming the barrier layer is determined in consideration of the coating property, the diffusibility of the donor element or the acceptor element, and the like.
  • the content of the alkaline earth metal or the metal compound containing an alkali metal in the barrier layer forming composition is preferably 0.1% by mass or more and 95% by mass or less, and more preferably 0.1% by mass or more. It is more preferably 80% by mass or less, further preferably 0.1% by mass or more and 70% by mass or less, particularly preferably 2% by mass or more and 60% by mass or less, and 10% by mass or more and 55% by mass or less.
  • the content of the alkaline earth metal or the metal compound containing the alkali metal is 0.1% by mass or more, the diffusion of the donor element or the acceptor element into the semiconductor substrate can be sufficiently inhibited.
  • the content is 95% by mass or less, the dispersibility of the alkaline earth metal or the metal compound containing the alkali metal in the barrier layer forming composition is improved, and the coating property to the substrate is improved.
  • the content of the alkaline earth metal and the metal compound containing the alkali metal in the total nonvolatile components of the barrier layer forming composition is preferably 0.5% by mass or more and less than 100% by mass, preferably 5% by mass. It is more preferably 70% by mass or less, and further preferably 10% by mass or more and 55% by mass or less. Within the above range, a sufficient barrier layer control effect tends to be obtained.
  • the non-volatile component refers to a component that does not volatilize when heat-treated at 600 ° C. or higher and 1500 ° C. or lower.
  • the non-volatile component can be obtained by a thermogravimetric analyzer TG, and the total content of the alkaline earth metal and the metal compound containing the alkali metal in the non-volatile component is determined by ICP emission spectroscopy / mass spectrometry (ICP-MS). Method) and atomic absorption method.
  • the composition for forming a barrier layer of the present invention contains one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils.
  • specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils.
  • the roughness of the surface of the semiconductor substrate is the arithmetic average roughness (Ra), maximum height (Ry), ten-point average roughness (Rz), and average interval of irregularities (Sm) in each part extracted at random from the surface of the semiconductor substrate. ),
  • the arithmetic average roughness (Ra) of the obtained semiconductor substrate is preferably 0.1 ⁇ m or less, more preferably 0.05 ⁇ m or less, and still more preferably 0.01 ⁇ m or less.
  • Ra is 0.1 ⁇ m or less, the characteristics of a solar cell using the same tend not to be deteriorated.
  • the content of the specific compound in all nonvolatile components of the barrier layer forming composition is preferably 0.5% by mass or more and 50% by mass or less, and more preferably 1% by mass or more and 25% by mass or less. Preferably, it is 5 mass% or more and 20 mass% or less.
  • the metal alkoxide is a compound obtained by reacting a specific metal atom and an alcohol, and is preferably represented by the following general formula (1).
  • M is Li, Na, K, Mg, Ca, Sr, Ba, La, Ti, B, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co
  • a is a positive number from 1 to 7 depending on the valence of the metal M
  • R 1 excludes the OH group of the alcohol Residue.
  • Examples of the alcohol that forms the metal alkoxide include those represented by the following formula (2).
  • R 1 represents a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, or a saturated or saturated group having 2 to 20 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms.
  • An unsaturated hydrocarbon group is a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, or a saturated or saturated group having 2 to 20 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms. An unsaturated hydrocarbon group.
  • the saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms represented by R 1 may be linear, branched or cyclic. Moreover, it is preferable that it is a saturated hydrocarbon group.
  • R 1 is a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms
  • examples of the alcohol represented by the formula (2) include methanol, ethanol, 1-propanol 2-propanol, butanol, amyl alcohol, cyclohexanol and the like.
  • examples of the alcohol represented by the formula (2) include methoxymethanol, methoxyethanol, Examples thereof include ethoxymethanol, ethoxyethanol, methoxypropanol, ethoxypropanol, and propoxypropanol.
  • the silicon alkoxide is preferably represented by the following formula (3).
  • R 2 represents a methyl group, a phenyl group, a vinyl group, an epoxy group, a styryl group, a methacryl group, an acrylic group, an amino group, a ureido group, a mercapto group, a sulfide group or an isocyanate group
  • R 3 Represents a methyl group, an ethyl group or a propyl group, and n represents 0 to 3.
  • R 2 is preferably a methyl group or a phenyl group
  • R 3 is preferably a methyl group or an ethyl group.
  • n is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
  • the silicon alkoxide it is preferable to use one or more selected from the group consisting of tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane, and tetraethoxysilane and tetramethoxysilane. It is more preferable to use one or more selected from the group consisting of Since tetraethoxysilane and tetramethoxysilane are rich in reactivity, it is easy to form a silicon oxide layer at the interface between the semiconductor substrate and the specific alkali compound, and to suppress surface roughness of the semiconductor substrate.
  • silicon alkoxide is preferable from the viewpoint of suppressing surface roughness of the semiconductor substrate.
  • Silicon alkoxide may be used in the form of a partially polymerized silicate oligomer or silicone oil. That is, you may use in the state which the hydrolysis and polycondensation of silicon alkoxide advanced.
  • Catalysts include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, boric acid, phosphoric acid, hydrofluoric acid; and formic acid, acetic acid, propionic acid, butyric acid, oleic acid, linoleic acid, salicylic acid, benzoic acid, phthalic acid, oxalic acid And organic acids such as lactic acid and succinic acid.
  • bases such as ammonia and an amine, as a catalyst.
  • An alkaline earth metal or a metal compound containing an alkali metal may also serve as a catalyst.
  • the silicate oligomer here is a compound represented by Si n O n-1 (OR) 2 (n + 1) obtained by hydrolysis and polycondensation of silicon alkoxide [R represents a methyl group, an ethyl group or a propyl group, n is preferably an integer of 3 to 10.
  • the silicate oligomer may be dissolved or dispersed in an alcohol solvent such as methanol, ethanol, propanol, or butanol.
  • silicate oligomer or silicone oil examples include silicates manufactured by Tama Chemical Co., Ltd. (silicate 40, silicate 45, M silicate 51, etc.), and silicates manufactured by Colcoat Co., Ltd. (methyl silicate 51, methyl silicate 53A, ethyl silicate 40).
  • Silicate oligomers such as ethyl silicate 48) and EMS-485, methyl silicone oils such as polydimethylsiloxane, silicone oils such as methylphenyl silicone oil, methyl hydrogen silicone oil, and modified silicone oil.
  • the inclusion of one or more selected from the group consisting of silicon alkoxide, methyl silicate oligomer and ethyl silicate oligomer is preferable because it tends to suppress surface roughness without reducing barrier performance.
  • the barrier layer forming composition of the present invention contains a dispersion medium.
  • the dispersion medium is a medium in which the alkaline earth metal or the metal compound containing the alkali metal is dispersed or dissolved in the composition.
  • the solvent examples include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, methyl-n-pentyl ketone, methyl-n-hexyl ketone, diethyl ketone, Ketone solvents such as propyl ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone; diethyl ether, methyl ethyl ether, methyl-n-propyl ether, diisopropyl Ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene
  • Alcohol solvents ethylene glycol monomethyl ether, ethylene glycol monoethyl ether (cellosolve), ethylene glycol Nophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl Glycol monoether solvents such as ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether; ⁇ -terpinene, ⁇ -terpineol, myrcene, alloocimene, limonene, dipentene, ⁇ -pinene, ⁇ -pinene, terpineol, carvone, Terpene solvents such as osymene and ferrand
  • the dispersion medium is preferably water, an alcohol solvent, a glycol monoether solvent, or a terpene solvent, and is water, alcohol, cellosolve, ⁇ -terpineol, diethylene glycol monoester.
  • N-Butyl ether or diethylene glycol mono-n-butyl ether is preferred, and water, alcohol, ⁇ -terpineol or cellosolve are preferred.
  • the content of the dispersion medium in the barrier layer forming composition is determined in consideration of the coating property and the dopant concentration.
  • the content is preferably 5% by mass or more and 99% by mass or less. It is more preferably 20% by mass or more and 95% by mass or less, and further preferably 40% by mass or more and 90% by mass or less.
  • the barrier layer-forming composition of the present invention preferably contains an organic binder.
  • the organic binder By containing the organic binder, the alkaline earth metal or the metal compound containing the alkali metal is bound to each other at a high temperature, and the alkaline earth metal or the metal compound containing the alkali metal is bound to the semiconductor substrate. It becomes easy to make.
  • organic binder examples include polyvinyl alcohol; polyacrylamide resin; polyvinyl amide resin; polyvinyl pyrrolidone resin; polyethylene oxide resin; polysulfone resin; acrylamide alkyl sulfone resin; cellulose derivatives such as cellulose ether, carboxymethyl cellulose, hydroxyethyl cellulose, and ethyl cellulose; Starch, starch derivative; sodium alginate; xanthan; guar, gua derivative; scleroglucan, scleroglucan derivative; tragacanth, tragacanth derivative; dextrin, dextrin derivative; (meth) acrylic acid resin; alkyl (meth) (Meth) acrylic acid ester resins such as acrylate resins and dimethylaminoethyl (meth) acrylate resins; Tajien resin; a styrene resin; butyral resin; and may select these copolymers as appropriate.
  • an acrylic acid resin, a butyral resin, or a cellulose derivative is included from a viewpoint of decomposability and prevention of dripping at the time of screen printing. These are used singly or in combination of two or more.
  • the molecular weight of the organic binder is not particularly limited, and it is desirable to adjust appropriately in view of the desired viscosity as the composition.
  • the content rate in the case of containing an organic binder is 0.5 mass% or more and 30 mass% or less in the composition for barrier layer formation, and it is 3 mass% or more and 25 mass% or less. More preferably, it is 3 mass% or more and 20 mass% or less.
  • the mass ratio of the total content of the alkaline earth metal and the metal compound containing the alkali metal to the total content of the organic binder (alkaline earth metal and alkali metal metal compound) / (organic binder) is 99.9. /0.1 to 0.1 / 99.9 is preferable, and 99/1 to 20/80 is more preferable.
  • a dispersion medium in which an organic binder is dissolved may be used as the dispersion medium and the organic binder.
  • composition for barrier layer formation may use isobornyl cyclohexanol exemplified as a solvent together with the organic binder or as a material replacing the organic binder.
  • Isobornylcyclohexanol is commercially available as “Telsolve® MTPH” (trade name, manufactured by Nippon Terpene Chemical Co., Ltd.).
  • Isobornylcyclohexanol has a high boiling point of 308 ° C to 318 ° C, and when it is removed from the barrier layer, it does not need to be degreased by firing like an organic binder, but must be vaporized by heating. Can do.
  • the content of isobornylcyclohexanol is 0.5% by mass to 85% by mass in the total mass of the composition for forming a barrier layer. It is preferably 1% by mass to 80% by mass, more preferably 2% by mass to 80% by mass.
  • the composition for forming a barrier layer is one or more specific compounds selected from the group consisting of an alkaline earth metal or an alkali metal-containing metal compound, a dispersion medium, a metal alkoxide, a silicon alkoxide, a silicate oligomer, and a silicone oil.
  • various additives such as a thickener, a wetting agent, a surfactant, an inorganic powder, and a thixotropic agent may be contained as necessary.
  • the surfactant examples include nonionic surfactants, cationic surfactants, and anionic surfactants.
  • nonionic surfactants or cationic surfactants are preferable because impurities such as heavy metals are not brought into the semiconductor device.
  • silicon surfactants, fluorine surfactants and hydrocarbon surfactants are exemplified as nonionic surfactants, and since they are rapidly baked during heating such as diffusion, hydrocarbon surfactants are preferable.
  • hydrocarbon-based surfactant examples include ethylene oxide-propylene oxide block copolymers, acetylene glycol compounds, and the like, and acetylene glycol compounds are more preferable because variations in resistance values of semiconductor devices are further reduced.
  • Examples of the inorganic powder include silicon oxide, silicon nitride, silicon oxide, silicon carbide powder and the like.
  • the barrier layer forming composition may contain a thixotropic agent.
  • a thixotropic property can be easily controlled, and a barrier layer forming composition for screen printing having a viscosity suitable for screen printing and a barrier layer forming composition for ink jet having a viscosity suitable for ink jet printing are provided. Can be configured. Furthermore, since the thixotropy is controlled, it is possible to suppress bleeding and sagging from the printed pattern of the barrier layer forming composition during printing.
  • thixotropic agents polyether compounds, fatty acid amide, organic filler, inorganic filler, hydrogenated castor oil, urea urethane amide, bio gum, guar gum, locust bean gum, carrageenan, pectin, agar, ⁇ -glucan, tamarind seed gum, psyllium seed gum , Polyvinyl pyrrolidone, silicone-based thickening gelling agent and oil-based gelling agent (trade name: Gelol (manufactured by Nippon Nippon Chemical Co., Ltd.)).
  • the organic binder described above may also serve as a thixotropic agent. Examples of such a material include ethyl cellulose.
  • the composition for forming a barrier layer of the present invention does not contaminate the semiconductor substrate, that is, from the viewpoint of suppressing carrier recombination in the semiconductor substrate, the content of iron, tungsten, gold, nickel, chromium, manganese, etc.
  • it is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 1% by mass or less.
  • the viscosity of the barrier layer forming composition is not particularly limited. Specifically, the viscosity measured at 25 ° C. with an E-type viscometer at a rotational speed of 0.5 rpm to 5 rpm is preferably 0.5 Pa ⁇ s to 400 Pa ⁇ s, preferably 40 Pa ⁇ s to 200 Pa ⁇ s. It is more preferable that When the barrier layer forming composition has a viscosity of 0.5 Pa ⁇ s or more, liquid dripping hardly occurs when applied to a semiconductor substrate, and when it is 400 Pa ⁇ s or less, a fine coating pattern can be formed. Become.
  • the composition for forming a barrier layer of the present invention is one or more selected from the group consisting of an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, a metal alkoxide, a silicon alkoxide, a silicate oligomer, and a silicone oil.
  • a component added as necessary can be obtained by mixing using a blender, a mixer, a mortar, or a rotor.
  • the heating temperature at this time can be, for example, 30 ° C. to 100 ° C.
  • the barrier layer forming composition is formed on a semiconductor substrate to form a patterned barrier layer, and the barrier layer on the semiconductor substrate is formed. And a step of diffusing a donor element or an acceptor element in a portion where the diffusion layer is not formed to partially form a diffusion layer in the semiconductor substrate.
  • the manufacturing method of the solar cell element of this invention includes the process of forming an electrode on the diffusion layer of the board
  • FIG. 1 is a schematic cross-sectional view conceptually showing an example of a manufacturing process of a solar cell substrate and a solar cell element of the present invention.
  • FIG. 1 demonstrates a back electrode type solar cell substrate and a solar cell element
  • the composition for forming a barrier layer of the present invention can be applied to any type of solar cell substrate and solar cell element.
  • a selective emitter type and a double-sided light receiving type can be exemplified.
  • a diffusion layer having a dopant concentration higher than that of other regions is formed immediately below the electrode on the light receiving surface side.
  • the barrier layer forming composition of the present invention can be used to form the high concentration diffusion layer region.
  • finger bars and bus bars are formed on both surfaces as electrodes, an n + type diffusion layer is formed on one surface of the semiconductor substrate, and a p + type diffusion layer is formed on the other surface.
  • the barrier layer forming composition of the present invention can be used.
  • an alkaline solution is applied to a silicon substrate which is an n-type semiconductor substrate 10 to remove a damaged layer, and a texture structure is obtained by etching.
  • the damaged layer on the surface of the silicon substrate generated when slicing from the ingot is removed with 20% by mass caustic soda.
  • the silicon substrate is etched with a mixed solution of 1% by mass caustic soda and 10% by mass isopropyl alcohol to form a texture structure on the n-type semiconductor substrate 10 (the description of the texture structure is omitted in the figure).
  • the solar cell element by forming a texture structure on the light-receiving surface (front surface) side of the n-type semiconductor substrate 10, a light confinement effect is promoted, and high efficiency is achieved.
  • the barrier layer forming composition 11 of the present invention is applied to the front surface (that is, the light receiving surface) of the n-type semiconductor substrate 10 and the back surface opposite to the light receiving surface.
  • the application method is not limited, and examples thereof include a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method, and it is preferable to use a printing method or an ink jet method.
  • the composition for forming a barrier layer there is no particular limitation as application amount of the composition for forming a barrier layer, it is possible to 0.01 g / m 2 or more 100 g / m 2 or less and preferably, 0.1 g / m 2 or more 20 g / m 2 or less Is more preferable.
  • a drying step for volatilizing the dispersion medium contained in the composition may be necessary after application.
  • drying is performed at a temperature of about 80 ° C. to 300 ° C. for about 1 to 10 minutes when using a hot plate, and about 10 to 30 minutes when using a dryer or the like.
  • This drying condition depends on the content of the dispersion medium of the barrier layer forming composition and is not particularly limited to the above condition in the present invention.
  • the barrier layer can be obtained as a dried product obtained by drying the barrier layer forming composition.
  • the patterned barrier layer can be obtained by applying the barrier layer forming composition 11 in a pattern in the case of a printing method, an inkjet method or the like.
  • the barrier layer forming composition 11 is applied to the entire surface, it is partially removed by etching or the like.
  • the barrier layer is obtained.
  • coating diffusion materials 12 and 13 for forming an n + type diffusion layer and a p + type diffusion layer are applied.
  • an n + -type diffusion layer 14 and a p + -type diffusion layer 15 are formed on the n-type semiconductor substrate 10 by thermal diffusion.
  • the heat treatment temperature for thermal diffusion is not particularly limited, but the heat treatment is preferably performed at a temperature of 750 ° C. to 1050 ° C. for 1 minute to 300 minutes.
  • a method of forming the n + -type diffusion layer 14 and the p + -type diffusion layer 15 at the same time is illustrated, but they may be diffused individually. That is, first, the coating diffusion material 13 for forming the p + -type diffusion layer 15 is applied and thermally diffused to remove the fired product 13 ′ of the coating diffusion material, and then the n + -type diffusion layer 14 is formed. The coating diffusion material 12 may be applied and thermally diffused to remove the fired product 12 'of the coating diffusion material.
  • the present invention can be similarly applied to a method using POCl 3 gas or BBr 3 gas.
  • a region where the p + -type diffusion layer 15 is to be formed is used as an opening, and a barrier layer is formed using the barrier layer forming composition other than the region used as the opening.
  • the barrier layer is removed.
  • a region where the n + -type diffusion layer 14 is to be formed is used as an opening, and a barrier layer is formed using the barrier layer forming composition other than the region used as the opening.
  • an n + type diffusion layer 14 is formed in the n type semiconductor substrate 10 corresponding to the opening.
  • the barrier layer forming composition 11 and the fired products 12 ′ and 13 ′ of the diffusion material for coating are removed to obtain a solar cell substrate.
  • the removal method include a method of immersing in an aqueous solution containing an acid, and a diffusion for coating for forming the barrier layer forming composition 11, and the n + type diffusion layer 14 and the p + type diffusion layer 15. It is preferably determined by the composition of the fired product 12 ', 13' of the material. Specifically, it is preferable to include a step of etching a glass layer formed on the semiconductor substrate by a thermal diffusion treatment with an aqueous solution containing hydrofluoric acid.
  • an alkaline earth metal or a metal compound containing an alkali metal is removed with hydrochloric acid (for example, 10% by mass HCl aqueous solution), washed with water, and further hydrofluoric acid aqueous solution (for example 2.5% by mass HF).
  • hydrochloric acid for example, 10% by mass HCl aqueous solution
  • hydrofluoric acid aqueous solution for example 2.5% by mass HF.
  • an antireflection film 16 is provided on the front surface which is a light receiving surface, and a passivation film 17 is provided on the back surface.
  • the antireflection film 16 and the passivation film 17 may have the same composition or different compositions.
  • Examples of the antireflection film 16 include a silicon nitride film, and examples of the passivation film 17 include a silicon oxide film.
  • the thickness of the antireflection film and the passivation film is not particularly limited, and is preferably 10 nm to 300 nm, and more preferably 30 nm to 150 nm.
  • a portion for forming an electrode is opened in the passivation film 17.
  • the opening can be formed by applying an etching solution (for example, a solution containing hydrofluoric acid, ammonium fluoride, or phosphoric acid) to a portion where the opening is desired by an inkjet method or the like, and performing heat treatment.
  • an etching solution for example, a solution containing hydrofluoric acid, ammonium fluoride, or phosphoric acid
  • an n electrode 18 and a p electrode 19 are formed on the n + type diffusion layer 14 and the p + type diffusion layer 15, respectively.
  • the material and forming method of the n electrode 18 and the p electrode 19 are not particularly limited.
  • the n-electrode 18 and the p-electrode 19 may be formed by applying an electrode forming paste containing aluminum, silver, or copper metal and drying the paste.
  • the n electrode 18 and the p electrode 19 are fired to complete the solar cell element.
  • the step of opening shown in FIG. 1 (7) can be omitted.
  • the glass frit melts the passivation film 17 on the back side, and the metal particles in the paste (For example, silver particles) form a contact portion with the silicon substrate 10 and solidify. Thereby, the formed surface electrodes 18 and 19 and the silicon substrate 10 are electrically connected. This is called fire-through.
  • the solar cell includes one or more of the solar cell elements, and is configured by arranging a wiring material on the electrode of the solar cell element.
  • a plurality of solar cell elements may be connected via a wiring material as necessary, and may be further sealed with a sealing material.
  • the wiring material and the sealing material are not particularly limited, and can be appropriately selected from those usually used in the industry.
  • % Means “% by mass” unless otherwise specified.
  • the volume average particle size of the alkaline earth metal or the metal compound containing the alkali metal in the examples is measured using a laser diffraction scattering method particle size distribution analyzer (LS 13 320 manufactured by Beckman Coulter), and the particle size in a dispersed state. Was measured.
  • composition 1 for forming a barrier layer 10 g (18% by mass) of calcium oxide (“CSQ” manufactured by Ube Materials, volume average particle diameter of 15.0 ⁇ m, amorphous particles), 10 g of tetraethoxysilane (“Taka Kagaku Kogyo”, “normal ethyl silicate”), pure water 25 g and 8.75 g of butyl carbitol (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a zirconia pot. Further, 50 g of a 3 mm bead mill was put in a zirconia pot, and a dispersion was obtained using a planetary ball mill (“pulverisete” manufactured by Fritsch) for 30 minutes at 600 rpm.
  • CSQ calcium oxide
  • Fritsch planetary ball mill
  • terpineol-LW manufactured by Terpene Chemical
  • ethylcellulose manufactured by Dow Chemical Co., Ltd., STD200
  • the viscosity of this composition 1 for forming a barrier layer 1 at 25 ° C. and 5 rpm was 45 Pa ⁇ s.
  • the viscosity was measured using an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) with the sampling amount of the barrier layer forming composition being 0.5 ml.
  • the barrier layer-forming composition 1 was applied by screen printing (MT-320T, manufactured by Microtech) and heated at 150 ° C. After drying on the plate for 5 minutes, it was dried on a hot plate at 500 ° C. for 1 minute. This is a substrate with a barrier layer.
  • a phosphorus diffusion solution was spin-coated at 500 rpm (MS-A100, manufactured by Mikasa) and dried at 200 ° C. This is a counter diffusion substrate.
  • the substrate with the barrier layer and the counter diffusion substrate were opposed to each other at a distance of 1 mm, and heated at 950 ° C. for 10 minutes to diffuse phosphorus into the substrate with the barrier layer. Thereafter, the substrate with the barrier layer was immersed in a 10% by mass HCl aqueous solution for 5 minutes, washed with water, and further immersed in a 2.5% by mass HF aqueous solution for 5 minutes. This was washed with water and dried, and then evaluated as follows.
  • the sheet resistance of the substrate to which the barrier layer forming composition 1 was applied was measured by a four-probe method using a Loresta-EP MCP-T360 type low resistivity meter manufactured by Mitsubishi Chemical Corporation.
  • the sheet resistance of the portion to which the barrier layer forming composition 1 was applied was 240 ⁇ / ⁇ .
  • the sheet resistance of the uncoated part was 40 ⁇ / ⁇ .
  • the n-type silicon substrate after slicing was immersed in a 2.5% by mass HF aqueous solution for 5 minutes, washed with water, and measured for sheet resistance after drying, which was 240 ⁇ / ⁇ . .
  • the surface roughness of the portion where the barrier layer was applied was measured using a surface roughness measuring device (manufactured by Mitutoyo Corporation, Surf Test “SJ-2100”.
  • the average surface roughness Ra was 0.01 ⁇ m or less.
  • the surface roughness was measured on one side of the pyramid shape of the texture structure.
  • the barrier layer forming composition contains an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, and one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils. It has been found that by using the barrier layer forming composition, it is possible to sufficiently prevent the dopant from diffusing into the semiconductor substrate and to suppress the occurrence of roughness on the surface of the semiconductor substrate where the barrier layer is formed.

Abstract

A barrier layer forming composition, containing: a metal compound containing an alkaline earth metal or an alkaline metal; a dispersion medium; and at least one type of specific compound selected from a group comprising a metal alkoxide, a silicon alkoxide, a silicate oligomer, and a silicone oil.

Description

バリア層形成用組成物、バリア層、太陽電池用基板の製造方法及び太陽電池素子の製造方法Barrier layer forming composition, barrier layer, method for producing solar cell substrate, and method for producing solar cell element
　本発明は、バリア層形成用組成物、バリア層、太陽電池用基板の製造方法及び太陽電池素子の製造方法に関する。 The present invention relates to a barrier layer forming composition, a barrier layer, a method for manufacturing a solar cell substrate, and a method for manufacturing a solar cell element.
　従来のシリコン太陽電池素子の製造工程について説明する。
　まず、光閉じ込め効果を促して高効率化を図るよう、受光面（表面）にテクスチャー構造を形成したｐ型シリコン基板を準備し、続いてオキシ塩化リン（ＰＯＣｌ３）、窒素及び酸素の混合ガス雰囲気において８００℃～９００℃で数十分の処理を行って、ｐ型シリコン基板の表面に一様にｎ型拡散層を形成する。次いで、受光面に銀（Ａｇ）等の電極ペースト、裏面側にアルミニウム（Ａｌ）等の電極ペーストを塗布した後、焼成することにより、太陽電池素子を得ていた。 The manufacturing process of the conventional silicon solar cell element is demonstrated.
First, a p-type silicon substrate having a texture structure formed on the light receiving surface (surface) is prepared so as to promote the light confinement effect, and then a mixed gas of phosphorus oxychloride (POCl 3 ), nitrogen and oxygen. A tens of minutes of treatment is performed at 800 ° C. to 900 ° C. in an atmosphere to form an n-type diffusion layer uniformly on the surface of the p-type silicon substrate. Next, after applying an electrode paste such as silver (Ag) on the light receiving surface and an electrode paste such as aluminum (Al) on the back side, the solar cell element was obtained by firing.
　しかしながら、受光面側の電極の直下には太陽光が入射しないため、その部分では発電しない。そこで受光面に電極がなく、裏面にｎ＋型拡散層とｐ＋型拡散層を有し、それぞれの拡散層の上にｎ電極及びｐ電極を有する裏面電極型太陽電池が開発されている（例えば、特開２０１１－５０７２４６号公報参照）。 However, since sunlight does not enter directly under the electrode on the light receiving surface side, power is not generated in that portion. Therefore, a back electrode type solar cell having no electrode on the light receiving surface, having an n + type diffusion layer and a p + type diffusion layer on the back surface, and having an n electrode and a p electrode on each diffusion layer has been developed ( For example, refer to JP 2011-507246 A).
　このような裏面電極型太陽電池を形成する方法について説明する。ｎ型シリコン基板の受光面及び裏面の全面にバリア層を形成する。ここで、バリア層は、シリコン基板内にドーパントが拡散するのを抑制する機能を有する。次に、シリコン基板の裏面のバリア層の一部を除去して開口部を形成する。そして、バリア層の開口部からｐ型ドーパントをシリコン基板の裏面に拡散させると、開口部に対応する領域のみｐ＋型拡散層が形成される。次に、シリコン基板の裏面のバリア層をすべて除去した後に、再度シリコン基板の裏面の全面にバリア層を形成する。そして、前記ｐ＋型拡散層を形成した領域とは異なる領域のバリア層の一部を除去して開口部を形成し、その開口部からｎ型ドーパントをシリコン基板の裏面に拡散させて、ｎ＋型拡散層を形成する。続いて、シリコン基板の裏面のバリア層をすべて除去することで、裏面にｐ＋型拡散層及びｎ＋型拡散層が形成される。更に、テクスチャー構造、反射防止膜、パッシベーション膜、電極等を形成することで裏面電極型太陽電池が完成する。 A method of forming such a back electrode type solar cell will be described. A barrier layer is formed on the entire light receiving surface and back surface of the n-type silicon substrate. Here, the barrier layer has a function of suppressing the diffusion of the dopant into the silicon substrate. Next, a part of the barrier layer on the back surface of the silicon substrate is removed to form an opening. Then, when the p-type dopant is diffused from the opening of the barrier layer to the back surface of the silicon substrate, a p + -type diffusion layer is formed only in a region corresponding to the opening. Next, after all the barrier layer on the back surface of the silicon substrate is removed, a barrier layer is formed again on the entire back surface of the silicon substrate. Then, a part of the barrier layer in a region different from the region where the p + -type diffusion layer is formed is removed to form an opening, and an n-type dopant is diffused from the opening to the back surface of the silicon substrate. A + type diffusion layer is formed. Subsequently, by removing all the barrier layer on the back surface of the silicon substrate, a p + -type diffusion layer and an n + -type diffusion layer are formed on the back surface. Furthermore, a back electrode type solar cell is completed by forming a texture structure, an antireflection film, a passivation film, an electrode, and the like.
　前記バリア層として、熱酸化法によりシリコン基板表面に生成させた酸化膜を利用する方法が提案されている（例えば、特開２００２－３２９８８０号公報参照）。一方、ＳｉＯ２前駆体を含むマスキングペーストを用いたバリア層の形成方法も提案されている（例えば、特開２００７－４９０７９号公報参照）。 As the barrier layer, a method using an oxide film formed on the surface of a silicon substrate by a thermal oxidation method has been proposed (see, for example, JP-A-2002-329880). On the other hand, a method for forming a barrier layer using a masking paste containing a SiO 2 precursor has also been proposed (see, for example, Japanese Patent Application Laid-Open No. 2007-49079).
　しかし、前述の特開２００２－３２９８８０号公報に記載の、熱酸化法によりシリコン基板表面に酸化膜を生成させる方法では、スループットが長いため、製造コストが高くなるという問題があった。
　また、特開２００７－４９０７９号公報に記載の、ＳｉＯ２前駆体を含有するマスキングペーストを用いる方法では、物理的にドナー元素又はアクセプター元素の拡散を防ぐものであること、更にＳｉＯ２からなるバリア層は緻密な膜を形成することが困難であるためピンホールを形成しやすいことから、ドーパントの基板への拡散を充分に防ぐことが困難であった。 However, the method of generating an oxide film on the surface of a silicon substrate by the thermal oxidation method described in Japanese Patent Application Laid-Open No. 2002-329880 described above has a problem that the manufacturing cost is high because the throughput is long.
Further, in the method using a masking paste containing a SiO 2 precursor described in Japanese Patent Application Laid-Open No. 2007-49079, it is intended to physically prevent diffusion of a donor element or an acceptor element, and further a barrier made of SiO 2. Since it is difficult to form a dense film in the layer, pinholes are easily formed. Therefore, it is difficult to sufficiently prevent diffusion of the dopant into the substrate.
　そこで本発明は、以上の従来の問題点に鑑みなされたものであり、ドナー元素又はアクセプター元素の半導体基板への拡散を充分に防ぎ、半導体基板の表面荒れを抑えることが可能なバリア層形成組成物、それを用いて形成されたバリア層、それを用いる太陽電池用基板の製造方法、及び太陽電池素子の製造方法を提供することを課題とする。 Therefore, the present invention has been made in view of the above conventional problems, and a barrier layer forming composition capable of sufficiently preventing the diffusion of a donor element or an acceptor element into a semiconductor substrate and suppressing the surface roughness of the semiconductor substrate. It is an object to provide an object, a barrier layer formed using the same, a method for manufacturing a solar cell substrate using the same, and a method for manufacturing a solar cell element.
　前記課題を解決するための具体的手段は以下の通りである。
＜１＞　アルカリ土類金属又はアルカリ金属を含有する金属化合物と、分散媒と、金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物と、を含有する、バリア層形成用組成物。 Specific means for solving the above problems are as follows.
<1> Contains an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, and one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils. A composition for forming a barrier layer.
＜２＞　前記特定化合物が、シリコンアルコキシド、メチルシリケートオリゴマー及びエチルシリケートオリゴマーからなる群より選択される１種以上を含む、前記＜１＞に記載のバリア層形成用組成物。 <2> The composition for forming a barrier layer according to <1>, wherein the specific compound includes one or more selected from the group consisting of silicon alkoxide, methyl silicate oligomer, and ethyl silicate oligomer.
＜３＞　前記特定化合物がシリコンアルコキシドを含み、前記シリコンアルコキシドが、テトラメトキシシラン及びテトラエトキシシランからなる群より選択される１種以上を含む、前記＜１＞又は＜２＞に記載のバリア層形成用組成物。 <3> The barrier layer according to <1> or <2>, wherein the specific compound includes silicon alkoxide, and the silicon alkoxide includes one or more selected from the group consisting of tetramethoxysilane and tetraethoxysilane. Forming composition.
＜４＞　不揮発成分中の、前記特定化合物の含有率が０．５質量％以上５０質量％以下である、前記＜１＞～＜３＞のいずれか１項に記載のバリア層形成用組成物。 <4> The composition for forming a barrier layer according to any one of <1> to <3>, wherein the content of the specific compound in the nonvolatile component is 0.5% by mass or more and 50% by mass or less. .
＜５＞　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、金属元素として、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される１種以上を含む、前記＜１＞～＜４＞のいずれか１項に記載のバリア層形成用組成物。 <5> The alkaline earth metal or the metal compound containing an alkali metal is selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium, and radium as the metal element. The composition for forming a barrier layer according to any one of <1> to <4>, comprising at least one kind.
＜６＞　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、酸化マグネシウム、酸化カルシウム、酸化カリウム、炭酸マグネシウム、炭酸カルシウム、硫酸マグネシウム、硫酸カルシウム、硝酸カルシウム、水酸化マグネシウム及び水酸化カルシウムからなる群より選択される１種以上を含む、前記＜１＞～＜５＞のいずれか１項に記載のバリア層形成用組成物。 <6> The alkaline earth metal or the metal compound containing an alkali metal is selected from magnesium oxide, calcium oxide, potassium oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, calcium sulfate, calcium nitrate, magnesium hydroxide, and calcium hydroxide. The composition for forming a barrier layer according to any one of <1> to <5>, comprising at least one selected from the group consisting of:
＜７＞　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、常温で固体の粒子であり、前記粒子の体積平均粒子径が３０μｍ以下である、前記＜１＞～＜６＞のいずれか１項に記載のバリア層形成用組成物。 <7> The above <1> to <6>, wherein the alkaline earth metal or the metal compound containing an alkali metal is a solid particle at room temperature, and the volume average particle diameter of the particle is 30 μm or less. 2. The barrier layer forming composition according to item 1.
＜８＞　更に有機バインダを含む、前記＜１＞～＜７＞のいずれか１項に記載のバリア層形成用組成物。 <8> The composition for forming a barrier layer according to any one of <1> to <7>, further comprising an organic binder.
＜９＞　前記有機バインダが、アクリル樹脂、ブチラール樹脂及びセルロース樹脂からなる群より選択される１種以上を含む、前記＜８＞に記載のバリア層形成用組成物。 <9> The composition for forming a barrier layer according to <8>, wherein the organic binder includes one or more selected from the group consisting of an acrylic resin, a butyral resin, and a cellulose resin.
＜１０＞　前記分散媒が、水、アルコール系溶剤、エーテル系溶剤、グリコールモノエーテル系溶剤及びテルペン系溶剤からなる群より選択される１種以上を含む、前記＜１＞～＜９＞のいずれか１項に記載のバリア層形成用組成物。 <10> Any of the above <1> to <9>, wherein the dispersion medium contains one or more selected from the group consisting of water, alcohol solvents, ether solvents, glycol monoether solvents, and terpene solvents. 2. The composition for forming a barrier layer according to item 1.
＜１１＞　不揮発成分中の、前記アルカリ土類金属又はアルカリ金属を含有する金属化合物の含有率が、０．５質量％以上１００質量％未満である、前記＜１＞～＜１０＞のいずれか１項に記載のバリア層形成用組成物。 <11> Any one of the above <1> to <10>, wherein a content ratio of the alkaline earth metal or the metal compound containing the alkali metal in the nonvolatile component is 0.5% by mass or more and less than 100% by mass 2. The barrier layer forming composition according to item 1.
＜１２＞　２５℃における粘度が０．５Ｐａ・ｓ以上４００Ｐａ・ｓ以下である前記＜１＞～＜１１＞のいずれか１項に記載のバリア層形成用組成物。 <12> The composition for forming a barrier layer according to any one of <1> to <11>, wherein the viscosity at 25 ° C. is 0.5 Pa · s or more and 400 Pa · s or less.
＜１３＞　不揮発成分中の、前記アルカリ土類金属又はアルカリ金属を含有する金属化合物の含有率が、１０質量％以上５５質量％以下である、前記＜１＞～＜１２＞に記載のバリア層形成用組成物。 <13> The barrier layer according to <1> to <12>, wherein a content of the alkaline earth metal or the metal compound containing the alkali metal in the nonvolatile component is 10% by mass to 55% by mass. Forming composition.
＜１４＞　２５℃における粘度が４０Ｐａ・ｓ以上２００Ｐａ・ｓ以下である前記＜１＞～＜１３＞のいずれか１項に記載のバリア層形成用組成物。 <14> The composition for forming a barrier layer according to any one of <1> to <13>, wherein the viscosity at 25 ° C. is 40 Pa · s or more and 200 Pa · s or less.
＜１５＞　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、酸化カルシウム及び炭酸カルシウムからなる群より選択される１種以上を含む、前記＜１＞～＜１４＞のいずれか１項に記載のバリア層形成用組成物。 <15> In any one of the above items <1> to <14>, wherein the alkaline earth metal or the metal compound containing an alkali metal includes one or more selected from the group consisting of calcium oxide and calcium carbonate The composition for forming a barrier layer as described.
＜１６＞　更に、チキソ剤を含有する、前記＜１＞～＜１５＞のいずれか１項に記載のバリア層形成用組成物。 <16> The composition for forming a barrier layer according to any one of <1> to <15>, further comprising a thixotropic agent.
＜１７＞　半導体基板に部分的に拡散層を形成するためのバリア層の形成に用いられる、前記＜１＞～＜１６＞のいずれか１項に記載のバリア層形成用組成物。 <17> The composition for forming a barrier layer according to any one of <1> to <16>, which is used for forming a barrier layer for partially forming a diffusion layer on a semiconductor substrate.
＜１８＞　前記＜１＞～＜１７＞のいずれか１項に記載のバリア層形成用組成物の乾燥体であるバリア層。 <18> A barrier layer, which is a dried body of the composition for forming a barrier layer according to any one of <1> to <17>.
＜１９＞　前記＜１＞～＜１７＞のいずれか１項に記載のバリア層形成用組成物を半導体基板上に付与してパターン状のバリア層を形成する工程と、
　前記半導体基板上の前記バリア層が形成されていない部分に、ドナー元素又はアクセプター元素を拡散して、前記半導体基板内に部分的に拡散層を形成する工程と、
　を含む、太陽電池用基板の製造方法。 <19> A step of applying the barrier layer forming composition according to any one of <1> to <17> onto a semiconductor substrate to form a patterned barrier layer;
A step of diffusing a donor element or an acceptor element in a portion where the barrier layer is not formed on the semiconductor substrate, and forming a diffusion layer partially in the semiconductor substrate;
The manufacturing method of the board | substrate for solar cells containing.
＜２０＞　前記バリア層形成用組成物を付与する方法が、印刷法又はインクジェット法である、前記＜１９＞に記載の太陽電池用基板の製造方法。 <20> The method for producing a solar cell substrate according to <19>, wherein the method for applying the barrier layer forming composition is a printing method or an inkjet method.
＜２１＞　前記＜１９＞又は＜２０＞に記載の製造方法により得られる太陽電池用基板の拡散層上に、電極を形成する工程を含む、太陽電池素子の製造方法。 <21> A method for producing a solar cell element, comprising a step of forming an electrode on a diffusion layer of a solar cell substrate obtained by the production method according to <19> or <20>.
　本発明によれば、ドナー元素又はアクセプター元素の半導体基板への拡散を充分に防ぎ、半導体基板の表面荒れを抑えることが可能なバリア層形成用組成物、それを用いて形成されたバリア層、それを用いる太陽電池用基板の製造方法、及び太陽電池素子の製造方法を提供することができる。 According to the present invention, a barrier layer forming composition that can sufficiently prevent the diffusion of a donor element or an acceptor element into a semiconductor substrate and suppress the surface roughness of the semiconductor substrate, a barrier layer formed using the composition, The manufacturing method of the board | substrate for solar cells using it, and the manufacturing method of a solar cell element can be provided.
本発明の太陽電池用基板及び太陽電池素子の製造工程の一例を概念的に示す断面図である。It is sectional drawing which shows notionally an example of the manufacturing process of the board | substrate for solar cells of this invention, and a solar cell element.
　まず、本発明のバリア層形成用組成物について説明し、次にバリア層形成用組成物を用いる太陽電池用基板の製造方法及び太陽電池素子の製造方法について説明する。
　尚、本明細書において「工程」との語は、独立した工程だけではなく、他の工程と明確に区別できない場合であってもその工程の目的が達成されれば、本用語に含まれる。また本明細書において「～」は、その前後に記載される数値をそれぞれ最小値及び最大値として含む範囲を示すものとする。更に本明細書において組成物中の各成分の量は、組成物中に各成分に該当する物質が複数存在する場合には、特に断らない限り、組成物中に存在する当該複数の物質の合計量を意味する。 First, the composition for forming a barrier layer of the present invention will be described, and then the method for manufacturing a solar cell substrate and the method for manufacturing a solar cell element using the composition for forming a barrier layer will be described.
In the present specification, the term “process” is not limited to an independent process, and is included in the term if the purpose of the process is achieved even when it cannot be clearly distinguished from other processes. In the present specification, “˜” indicates a range including the numerical values described before and after the values as the minimum value and the maximum value, respectively. Further, in this specification, the amount of each component in the composition is the sum of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. Means quantity.
　また、ドナー元素又はアクセプター元素を、ドーパントという場合がある。
　なお、本発明におけるバリア層は、半導体基板を平面図として観察したときに、全面に形成される場合のみならず、一部に形成される場合をも包含される。 In addition, the donor element or the acceptor element may be referred to as a dopant.
Note that the barrier layer in the present invention includes not only the case where the barrier layer is formed on the entire surface when the semiconductor substrate is observed as a plan view, but also the case where the barrier layer is formed on a part thereof.
＜バリア層形成用組成物＞
　本発明のバリア層形成用組成物は、アルカリ土類金属又はアルカリ金属を含有する金属化合物（以下、「特定アルカリ化合物」ともいう）と、分散媒と、金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物と、を含有する。本発明のバリア層形成用組成物は、ドーパントであるドナー元素又はアクセプター元素の半導体基板への拡散を阻害する。そのため、半導体基板においてドナー元素又はアクセプター元素を拡散したくない領域に、本発明のバリア層形成用組成物を用いてバリア層を形成することで、前記領域でのドナー元素及びアクセプター元素の拡散を充分に防止することができる。よって、半導体基板内に選択的にドーピング領域を形成することが可能である。この理由について、以下のように考えることができる。 <Barrier layer forming composition>
The composition for forming a barrier layer of the present invention includes an alkaline earth metal or a metal compound containing an alkali metal (hereinafter also referred to as “specific alkali compound”), a dispersion medium, a metal alkoxide, a silicon alkoxide, a silicate oligomer, and a silicone. And one or more specific compounds selected from the group consisting of oils. The composition for forming a barrier layer of the present invention inhibits diffusion of a donor element or an acceptor element, which is a dopant, into a semiconductor substrate. Therefore, by forming a barrier layer using the barrier layer forming composition of the present invention in a region where the donor element or the acceptor element is not desired to be diffused in the semiconductor substrate, the donor element and the acceptor element are diffused in the region. It can be sufficiently prevented. Therefore, it is possible to selectively form a doping region in the semiconductor substrate. The reason for this can be considered as follows.
　特定アルカリ化合物をバリア層形成用組成物に含有させ、このバリア層形成用組成物を半導体基板に塗布した後に、ドーパントを含有するドーピング化合物を付与すると、特定アルカリ化合物とドーピング化合物との間で反応が起こる。この反応は、ドーピング化合物と半導体基板との反応よりも反応性が高いため、ドナー元素又はアクセプター元素が半導体基板へ拡散するのが阻害されると考えられる。 When a specific alkali compound is contained in the composition for forming a barrier layer, and the composition for forming a barrier layer is applied to a semiconductor substrate, and a doping compound containing a dopant is applied, a reaction occurs between the specific alkali compound and the doping compound. Happens. Since this reaction is more reactive than the reaction between the doping compound and the semiconductor substrate, it is considered that the diffusion of the donor element or the acceptor element into the semiconductor substrate is hindered.
　なお、一般的に、ドナー元素又はアクセプター元素を含有するドーピング化合物としては、酸化リン、酸化ホウ素、オキシ塩化リン等が用いられ、これらはいずれも酸性化合物（又は水と反応して酸性を示す化合物）である。そのため、特に、特定アルカリ化合物は塩基性化合物であることが好ましい。塩基性化合物の特定アルカリ化合物は、ドーピング化合物との間で酸塩基反応し、この酸塩基反応は反応性が高いため、より効果的にドナー元素又はアクセプター元素が半導体基板へ拡散するのを阻害する。 In general, as a doping compound containing a donor element or an acceptor element, phosphorus oxide, boron oxide, phosphorus oxychloride, or the like is used, and these are all acidic compounds (or compounds that react with water to show acidity). ). Therefore, in particular, the specific alkali compound is preferably a basic compound. The specific alkali compound of the basic compound undergoes an acid-base reaction with the doping compound, and this acid-base reaction is highly reactive, thereby more effectively preventing the donor element or acceptor element from diffusing into the semiconductor substrate. .
　前記特定アルカリ化合物としては、５００℃以上の高温でも熱的に安定な金属化合物であることが好ましい。塩基性の金属化合物としては、アルカリ土類金属又はアルカリ金属を含有する金属化合物が好ましい。 The specific alkali compound is preferably a metal compound that is thermally stable even at a high temperature of 500 ° C. or higher. As the basic metal compound, an alkaline earth metal or a metal compound containing an alkali metal is preferable.
　アルカリ土類金属又はアルカリ金属を含有する金属化合物は、半導体基板に溶け込んだ際に、半導体基板中でキャリアの再結合中心として作用しないため、太陽電池用基板の変換効率を低下させるという不具合を抑えることができる。 An alkaline earth metal or a metal compound containing an alkali metal does not act as a carrier recombination center in a semiconductor substrate when it is dissolved in the semiconductor substrate, thereby suppressing the problem of reducing the conversion efficiency of the solar cell substrate. be able to.
　また、本発明のバリア層形成用組成物は、金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物を含む。特定化合物を含むバリア層形成用組成物を用いることで、バリア層の形成工程において、特定アルカリ化合物による半導体基板の侵食が抑制され、半導体基板の表面荒れの発生を抑制することができる。半導体基板の表面荒れの発生を抑制することで、半導体基板であるシリコン基板への損傷を抑えることができ、それを用いた太陽電池素子の発電特性の低下を抑制することができる。 The barrier layer-forming composition of the present invention contains one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils. By using the composition for forming a barrier layer containing the specific compound, the erosion of the semiconductor substrate by the specific alkali compound is suppressed in the barrier layer forming step, and the occurrence of surface roughness of the semiconductor substrate can be suppressed. By suppressing the occurrence of surface roughness of the semiconductor substrate, damage to the silicon substrate, which is a semiconductor substrate, can be suppressed, and a decrease in power generation characteristics of a solar cell element using the semiconductor substrate can be suppressed.
（アルカリ土類金属又はアルカリ金属を含有する金属化合物）
　本発明のバリア層形成用組成物は、アルカリ土類金属又はアルカリ金属を含有する金属化合物を含有する。アルカリ土類金属又はアルカリ金属を含有する金属化合物を含有するバリア層形成用組成物を用いることで、ドナー元素又はアクセプター元素が半導体基板へ拡散するのを阻害することができる。 (Alkaline earth metal or metal compound containing alkali metal)
The composition for forming a barrier layer of the present invention contains an alkaline earth metal or a metal compound containing an alkali metal. By using the composition for forming a barrier layer containing an alkaline earth metal or a metal compound containing an alkali metal, it is possible to inhibit the donor element or the acceptor element from diffusing into the semiconductor substrate.
　アルカリ土類金属又はアルカリ金属を含有する金属化合物は、常温（約２０℃）において液体であっても固体であってもよい。高温においても充分なバリア層性能を保持するには高温でも化学的に安定である必要があるという観点からは、熱拡散する高温（例えば５００℃以上）において固体であることが好ましい。ここで、例えば、アルカリ土類金属又はアルカリ金属を含有する金属化合物としては、アルカリ土類金属又はアルカリ金属を含有する金属酸化物、及びアルカリ土類金属又はアルカリ金属を含有する金属塩が挙げられる。 The alkaline earth metal or the metal compound containing the alkali metal may be liquid or solid at room temperature (about 20 ° C.). From the viewpoint that it is necessary to be chemically stable even at a high temperature in order to maintain a sufficient barrier layer performance even at a high temperature, it is preferably a solid at a high temperature (for example, 500 ° C. or higher) at which heat is diffused. Here, for example, the alkaline earth metal or the metal compound containing an alkali metal includes an alkaline earth metal or a metal oxide containing an alkali metal, and an alkaline earth metal or a metal salt containing an alkali metal. .
　アルカリ土類金属又はアルカリ金属を含有する金属化合物としては、特に制限されず、ドナー元素又はアクセプター元素を熱拡散する７００℃以上の高温において、塩基性化合物に変化する材料であることが好ましい。更に強い塩基性を示す観点から、金属化合物が金属元素としてマグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される１種以上を含有することが好ましく、マグネシウム、カルシウム、バリウム、カリウム、ナトリウムからなる群より選択される１種以上を含有することがより好ましく、マグネシウム、カルシウム及びカリウムからなる群より選択される１種以上を含有することが更に好ましく、低毒性、入手の容易さという観点から、マグネシウム及びカルシウムからなる群より選択される１種以上を含有することが特に好ましい。そして、化学的安定性の観点から、これらの金属元素からなる群より選択される１種以上を含有する金属酸化物、金属炭酸塩、金属硝酸塩、金属硫酸塩及び金属水酸化物からなる群より選択される１種以上であることが好ましく、金属酸化物、金属炭酸塩及び金属水酸化物からなる群より選択される１種以上であることがより好ましい。 The metal compound containing an alkaline earth metal or an alkali metal is not particularly limited, and is preferably a material that changes to a basic compound at a high temperature of 700 ° C. or higher at which a donor element or an acceptor element is thermally diffused. From the viewpoint of exhibiting stronger basicity, the metal compound contains at least one selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium as a metal element. It is more preferable that it contains at least one selected from the group consisting of magnesium, calcium, barium, potassium and sodium, and more preferably contains at least one selected from the group consisting of magnesium, calcium and potassium. More preferably, from the viewpoint of low toxicity and availability, it is particularly preferable to contain one or more selected from the group consisting of magnesium and calcium. And from the viewpoint of chemical stability, from the group consisting of metal oxides, metal carbonates, metal nitrates, metal sulfates and metal hydroxides containing one or more selected from the group consisting of these metal elements It is preferable that it is 1 or more types selected, and it is more preferable that it is 1 or more types selected from the group which consists of a metal oxide, a metal carbonate, and a metal hydroxide.
　特に、酸化ナトリウム、酸化カリウム、酸化リチウム、酸化カルシウム、酸化マグネシウム、酸化ルビジウム、酸化セシウム、酸化ベリリウム、酸化ストロンチウム、酸化バリウム、酸化ラジウム等の金属酸化物及びこれらの複合酸化物；水酸化ナトリウム、水酸化カリウム、水酸化リチウム、水酸化カルシウム、水酸化マグネシウム、水酸化ルビジウム、水酸化セシウム、水酸化ベリリウム、水酸化ストロンチウム、水酸化バリウム、水酸化ラジウム等の金属水酸化物；炭酸ナトリウム、炭酸カリウム、炭酸リチウム、炭酸カルシウム、炭酸マグネシウム、炭酸ルビジウム、炭酸セシウム、炭酸ベリリウム、炭酸ストロンチウム、炭酸バリウム、炭酸ラジウム等の金属炭酸塩；硝酸ナトリウム、硝酸カリウム、硝酸リチウム、硝酸カルシウム、硝酸マグネシウム、硝酸ルビジウム、硝酸セシウム、硝酸ベリリウム、硝酸ストロンチウム、硝酸バリウム、硝酸ラジウム等の金属硝酸塩；硫酸ナトリウム、硫酸カリウム、硫酸リチウム、硫酸カルシウム、硫酸マグネシウム、硫酸ルビジウム、硫酸セシウム、硫酸ベリリウム、硫酸ストロンチウム、硫酸バリウム、硫酸ラジウム等の金属硫酸塩；シュウ酸カルシウム、シュウ酸マグネシウム、シュウ酸バリウム、シュウ酸カリウム、シュウ酸ナトリウム、シュウ酸リチウム等のシュウ酸塩；塩化カリウム、塩化リチウム、塩化ナトリウム、塩化マグネシウム、塩化カルシウム、塩化バリウム、塩化ストロンチウム、塩化セシウム、塩化ルビジウム等の塩化物；などを用いることが好ましい。
　より好ましくは、前記金属酸化物及びこれらの複合酸化物、金属水酸化物、及び金属炭酸塩からなる群より選択される１種以上を用いることである。 In particular, metal oxides such as sodium oxide, potassium oxide, lithium oxide, calcium oxide, magnesium oxide, rubidium oxide, cesium oxide, beryllium oxide, strontium oxide, barium oxide, radium oxide, and complex oxides thereof; sodium hydroxide, Metal hydroxides such as potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, beryllium hydroxide, strontium hydroxide, barium hydroxide, radium hydroxide; sodium carbonate, carbonic acid Metal carbonates such as potassium, lithium carbonate, calcium carbonate, magnesium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, strontium carbonate, barium carbonate, radium carbonate; sodium nitrate, potassium nitrate, lithium nitrate, calcium nitrate Metal nitrates such as magnesium nitrate, rubidium nitrate, cesium nitrate, beryllium nitrate, strontium nitrate, barium nitrate, radium nitrate; sodium sulfate, potassium sulfate, lithium sulfate, calcium sulfate, magnesium sulfate, rubidium sulfate, cesium sulfate, beryllium sulfate, Metal sulfates such as strontium sulfate, barium sulfate and radium sulfate; oxalates such as calcium oxalate, magnesium oxalate, barium oxalate, potassium oxalate, sodium oxalate, lithium oxalate; potassium chloride, lithium chloride, chloride It is preferable to use chlorides such as sodium, magnesium chloride, calcium chloride, barium chloride, strontium chloride, cesium chloride, and rubidium chloride.
More preferably, at least one selected from the group consisting of the metal oxides and their composite oxides, metal hydroxides, and metal carbonates is used.
　これらの中でも、低毒性及び入手の容易さという観点から、炭酸ナトリウム、酸化ナトリウム、炭酸カリウム、酸化カリウム、炭酸カルシウム、水酸化カルシウム、酸化カルシウム、炭酸マグネシウム、水酸化マグネシウム、硫酸マグネシウム、硫酸カルシウム、硝酸カルシウム、及び酸化マグネシウムから選択される１種以上を用いることが好ましく、酸化マグネシウム、酸化カルシウム、炭酸マグネシウム、炭酸カルシウム、硫酸マグネシウム、硫酸カルシウム、硝酸カルシウム、酸化カリウム、水酸化マグネシウム、ステアリン酸カルシウム、及び水酸化カルシウムからなる群より選択される１種以上を用いることがより好ましく、炭酸カルシウム、酸化カルシウム、酸化カリウム、水酸化カルシウム、炭酸マグネシウム及び酸化マグネシウムから選択される１種以上を用いることが更に好ましく、炭酸カルシウム、酸化カルシウムから選択される１種以上を用いることが特に好ましい。 Among these, from the viewpoint of low toxicity and easy availability, sodium carbonate, sodium oxide, potassium carbonate, potassium oxide, calcium carbonate, calcium hydroxide, calcium oxide, magnesium carbonate, magnesium hydroxide, magnesium sulfate, calcium sulfate, It is preferable to use at least one selected from calcium nitrate and magnesium oxide, magnesium oxide, calcium oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, calcium sulfate, calcium nitrate, potassium oxide, magnesium hydroxide, calcium stearate, And at least one selected from the group consisting of calcium hydroxide, calcium carbonate, calcium oxide, potassium oxide, calcium hydroxide, magnesium carbonate, and magnesium oxide. More preferably to use at least one selected from Neshiumu, calcium carbonate, it is particularly preferable to use at least one selected from calcium oxide.
　アルカリ土類金属又はアルカリ金属を含有する金属化合物、又はそれを８００℃以上で空気中又は不活性雰囲気中で熱処理した化合物の塩基強度は、１２．２以上であることが好ましく、１７．２以上であることがより好ましく、２６．５以上であることが更に好ましい。８００℃以上とは、実際にドナー元素やアクセプター元素を拡散する温度として採用され得る温度であり、実際の使用環境を反映している。アルカリ土類金属又はアルカリ金属を含有する金属化合物の表面積や粒子径が同等の場合、塩基強度が大きいほど、それを用いて形成したバリア層のバリア能力、つまり、ドナー元素やアクセプター元素の拡散を阻害する能力が高くなる。 The base strength of an alkaline earth metal or a metal compound containing an alkali metal or a compound obtained by heat-treating it in air or in an inert atmosphere at 800 ° C. or higher is preferably 12.2 or higher, and 17.2 or higher. It is more preferable that it is 26.5 or more. 800 ° C. or higher is a temperature that can be adopted as a temperature for actually diffusing a donor element or an acceptor element and reflects an actual use environment. When the surface area and particle diameter of an alkaline earth metal or a metal compound containing an alkali metal are the same, the higher the base strength, the more the barrier ability of the barrier layer formed using it, i.e., the diffusion of donor and acceptor elements. Increases ability to inhibit.
　ここでいう塩基強度とは、Ｈａｍｍｅｔｔ指示薬を用いた酸度関数Ｈ－であり、指示薬を吸着させたときの色の変化によって測定できる。具体的には、指示薬として２，４，６－トリニトロアニリンを用い、黄色から赤橙色へ変化した場合のＨ－が１２．２以上、２，４－ジニトロアニリンを用い、黄色から紫色に変化した場合のＨ－が１５．０以上、４－クロロ－２－ニトロアニリンを用い、黄色から橙色に変化した場合のＨ－が１８．４以上、４－クロロアニリンを用い、黄色から桃色に変化した場合のＨ－が２６．５以上である。 The base strength here is an acidity function H − using a Hammett indicator and can be measured by a change in color when the indicator is adsorbed. Specifically, when 2,4,6-trinitroaniline is used as an indicator, H − is 12.2 or more when yellow changes to red-orange, and when 2,4-dinitroaniline is used, it changes from yellow to purple. When H − is 15.0 or higher and 4-chloro-2-nitroaniline is used, the color changes from yellow to orange. When H − is 18.4 or higher and 4-chloroaniline is used, the color changes from yellow to pink. In this case, H − is 26.5 or more.
　アルカリ土類金属又はアルカリ金属を含有する金属化合物の表面は、酸化ケイ素、酸化ジルコニウム、酸化亜鉛、酸化チタン、酸化アルミニウム等の金属酸化物で表面処理されていてもよい。表面処理が施されることによって、アルカリ土類金属又はアルカリ金属を含有する金属化合物とシリコン基板との反応性を抑制でき、これを付与した半導体基板の表面荒れを抑制できる傾向にある。
　金属酸化物による表面処理量としては特に制限はなく、金属化合物の表面における金属酸化物の量は、アルカリ土類金属又はアルカリ金属を含有する金属化合物に対して０．０１質量％以上３０質量％以下であることが好ましく、０．５質量％以上２０質量％以下であることがより好ましく、１質量％以上１５質量％以下であることが更に好ましい。 The surface of the alkaline earth metal or the metal compound containing the alkali metal may be surface-treated with a metal oxide such as silicon oxide, zirconium oxide, zinc oxide, titanium oxide, or aluminum oxide. By performing the surface treatment, the reactivity between the alkaline earth metal or the metal compound containing the alkali metal and the silicon substrate can be suppressed, and the surface roughness of the semiconductor substrate to which the silicon substrate is provided tends to be suppressed.
There is no restriction | limiting in particular as surface treatment amount by a metal oxide, The quantity of the metal oxide in the surface of a metal compound is 0.01 mass% or more and 30 mass% with respect to the metal compound containing an alkaline-earth metal or an alkali metal. Or less, more preferably 0.5% by mass or more and 20% by mass or less, and further preferably 1% by mass or more and 15% by mass or less.
　アルカリ土類金属又はアルカリ金属を含有する金属化合物が、常温（２５℃）で固体の場合であって粒子形状を呈している場合、その粒子の粒子径は３０μｍ以下であることが好ましく、０．０１μｍ～３０μｍであることがより好ましく、０．０２μｍ～１０μｍであることが更に好ましく、０．０３μｍ～５μｍであることが特に好ましい。
　粒子径が３０μｍ以下であると、半導体基板の所望の領域に均一にドナー元素又はアクセプター元素を拡散（ドープ）させやすい。また、０．０１μｍ以上であると、バリア層形成用組成物中にアルカリ土類金属又はアルカリ金属を含有する金属化合物を分散させやすい。また、アルカリ土類金属又はアルカリ金属を含有する金属化合物は分散媒に溶解していてもよい。
　なお、粒子径は、体積平均粒子径を表し、レーザー散乱回折法粒度分布測定装置等により測定することができる。体積平均粒子径は、粒子に照射したレーザー光の散乱光強度と角度の関係を検出し、Ｍｉｅ散乱理論に基づいて算出することができる。測定する際の分散媒に特に制限はないが、測定対象とする粒子が溶解しない分散媒を用いることが好ましい。 When the alkaline earth metal or the metal compound containing the alkali metal is solid at room temperature (25 ° C.) and has a particle shape, the particle diameter of the particles is preferably 30 μm or less. It is more preferably from 01 μm to 30 μm, further preferably from 0.02 μm to 10 μm, and particularly preferably from 0.03 μm to 5 μm.
When the particle diameter is 30 μm or less, the donor element or the acceptor element is easily diffused (doped) into a desired region of the semiconductor substrate. Moreover, it is easy to disperse | distribute the alkaline earth metal or the metal compound containing an alkali metal in the composition for barrier layer formation as it is 0.01 micrometer or more. Moreover, the alkaline earth metal or the metal compound containing an alkali metal may be dissolved in the dispersion medium.
The particle diameter represents a volume average particle diameter, and can be measured with a laser scattering diffraction particle size distribution measuring apparatus or the like. The volume average particle diameter can be calculated based on the Mie scattering theory by detecting the relationship between the scattered light intensity and the angle of the laser light applied to the particles. Although there is no restriction | limiting in particular in the dispersion medium at the time of measuring, It is preferable to use the dispersion medium which the particle | grains made into a measurement object do not melt | dissolve.
　粒子径が３０μｍ以下の特定アルカリ化合物の粒子を得る方法としては特に制限は無く、例えば粉砕処理をして得ることができる。粉砕手法としては、乾式粉砕法及び湿式粉砕法が採用できる。乾式粉砕法としては、ジェットミル、振動ミル、ボールミル等が採用できる。湿式粉砕法としてはビーズミル、ボールミル等が使用できる。 The method for obtaining particles of a specific alkali compound having a particle size of 30 μm or less is not particularly limited, and can be obtained by, for example, pulverization. As a grinding method, a dry grinding method and a wet grinding method can be employed. As the dry pulverization method, a jet mill, a vibration mill, a ball mill, or the like can be employed. As the wet pulverization method, a bead mill, a ball mill or the like can be used.
　粉砕処理に際して粉砕装置に起因する不純物がバリア層形成用組成物に混入すると、半導体基板内のキャリアのライフタイム低下を招く恐れがあるため、粉砕容器、ビーズ、ボール等の材質は半導体基板への影響の少ない材質を選択することが好ましい。粉砕時に好適に用いられる容器等の材質としては、アルミナ、部分安定化ジルコニア等が挙げられる。また、粒子径が３０μｍ以下の特定アルカリ化合物の粒子を得る方法としては、粉砕手法以外に、気相酸化法、加水分解法等を用いることができる。 When impurities resulting from the pulverization apparatus are mixed into the barrier layer forming composition during the pulverization process, the lifetime of the carriers in the semiconductor substrate may be reduced. It is preferable to select a material with little influence. Examples of the material of the container and the like that are preferably used during pulverization include alumina and partially stabilized zirconia. As a method for obtaining particles of a specific alkali compound having a particle size of 30 μm or less, a gas phase oxidation method, a hydrolysis method, or the like can be used in addition to the pulverization method.
　また、特定アルカリ化合物の粒子は、アルカリ土類金属又はアルカリ金属を含有する金属化合物以外の化合物で構成された粒子（例えば酸化ケイ素粒子）を担体とし、この担体の表面にアルカリ土類金属又はアルカリ金属を含有する金属化合物が被覆又は分散担持された材料であってもよい。この形態では、アルカリ土類金属又はアルカリ金属を含有する金属化合物の有効表面積を大きくすることが可能であり、ドナー元素又はアクセプター元素の半導体基板への拡散を阻害する特性が向上する可能性がある。 In addition, the particles of the specific alkali compound are particles made of a compound other than an alkaline earth metal or a metal compound containing an alkali metal (for example, silicon oxide particles) as a carrier, and an alkaline earth metal or alkali is formed on the surface of the carrier. A material in which a metal compound containing a metal is coated or dispersedly supported may be used. In this embodiment, it is possible to increase the effective surface area of the alkaline earth metal or the metal compound containing the alkali metal, and there is a possibility that the property of inhibiting the diffusion of the donor element or the acceptor element into the semiconductor substrate may be improved. .
　前記担体としては１０ｍ２／ｇ以上のＢＥＴ比表面積を示す材料が好ましく、ＳｉＯ２、活性炭、カーボンファイバー、酸化亜鉛等の無機材料の粒子を例示することができる。 The carrier is preferably a material having a BET specific surface area of 10 m 2 / g or more, and examples thereof include particles of inorganic materials such as SiO 2 , activated carbon, carbon fiber, and zinc oxide.
　特定アルカリ化合物の粒子の形状は特に制限されず、略球状、扁平状、鱗片状、ブロック状、楕球状、板状、海胆状、多孔質球状及び棒状のいずれであってもよい。前記粒子の形状は、電子顕微鏡等によって確認することができる。 The shape of the particles of the specific alkali compound is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a scale shape, a block shape, an oval shape, a plate shape, a sea gall shape, a porous sphere shape, and a rod shape. The shape of the particles can be confirmed by an electron microscope or the like.
　バリア層形成用組成物中のアルカリ土類金属又はアルカリ金属を含有する金属化合物の含有量は、塗布性、ドナー元素又はアクセプター元素の拡散性等を考慮し決定される。一般には、バリア層形成用組成物中のアルカリ土類金属又はアルカリ金属を含有する金属化合物の含有率は、０．１質量％以上９５質量％以下であることが好ましく、０．１質量％以上８０質量％以下であることがより好ましく、０．１質量％以上７０質量％以下であることが更に好ましく、２質量％以上６０質量％以下であることが特に好ましく、１０質量％以上５５質量％以下であることが極めて好ましい。アルカリ土類金属又はアルカリ金属を含有する金属化合物の含有率が０．１質量％以上であると、ドナー元素又はアクセプター元素の半導体基板中への拡散を充分に阻害することができる。９５質量％以下であると、バリア層形成用組成物中のアルカリ土類金属又はアルカリ金属を含有する金属化合物の分散性が良好になり、基板への塗布性が向上する。 The content of the alkaline earth metal or the metal compound containing the alkali metal in the composition for forming the barrier layer is determined in consideration of the coating property, the diffusibility of the donor element or the acceptor element, and the like. In general, the content of the alkaline earth metal or the metal compound containing an alkali metal in the barrier layer forming composition is preferably 0.1% by mass or more and 95% by mass or less, and more preferably 0.1% by mass or more. It is more preferably 80% by mass or less, further preferably 0.1% by mass or more and 70% by mass or less, particularly preferably 2% by mass or more and 60% by mass or less, and 10% by mass or more and 55% by mass or less. Very preferably, When the content of the alkaline earth metal or the metal compound containing the alkali metal is 0.1% by mass or more, the diffusion of the donor element or the acceptor element into the semiconductor substrate can be sufficiently inhibited. When the content is 95% by mass or less, the dispersibility of the alkaline earth metal or the metal compound containing the alkali metal in the barrier layer forming composition is improved, and the coating property to the substrate is improved.
　また、バリア層形成用組成物の全不揮発成分中のアルカリ土類金属及びアルカリ金属を含有する金属化合物の含有率は、０．５質量％以上１００質量％未満であることが好ましく、５質量％以上７０質量％以下であることがより好ましく、１０質量％以上５５質量％以下であることが更に好ましい。上記範囲内であることで、充分なバリア層制御効果が得られる傾向にある。 The content of the alkaline earth metal and the metal compound containing the alkali metal in the total nonvolatile components of the barrier layer forming composition is preferably 0.5% by mass or more and less than 100% by mass, preferably 5% by mass. It is more preferably 70% by mass or less, and further preferably 10% by mass or more and 55% by mass or less. Within the above range, a sufficient barrier layer control effect tends to be obtained.
　ここで、不揮発成分とは６００℃以上１５００℃以下で熱処理した際に揮発しない成分のことを指す。なお不揮発成分は熱重量分析計ＴＧにより求めることが可能であり、不揮発成分中のアルカリ土類金属及びアルカリ金属を含有する金属化合物の総含有率はＩＣＰ発光分光分析／質量分析法（ＩＣＰ－ＭＳ法）、原子吸光法により求めることが可能である。 Here, the non-volatile component refers to a component that does not volatilize when heat-treated at 600 ° C. or higher and 1500 ° C. or lower. The non-volatile component can be obtained by a thermogravimetric analyzer TG, and the total content of the alkaline earth metal and the metal compound containing the alkali metal in the non-volatile component is determined by ICP emission spectroscopy / mass spectrometry (ICP-MS). Method) and atomic absorption method.
（特定化合物）
　本発明のバリア層形成用組成物は金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物を含む。特定化合物を含むことで、バリア層の形成工程における半導体基板の侵食が抑制され、半導体基板の表面荒れの発生を抑制することができる。 (Specific compounds)
The composition for forming a barrier layer of the present invention contains one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils. By including the specific compound, the erosion of the semiconductor substrate in the barrier layer forming step can be suppressed, and the occurrence of surface roughness of the semiconductor substrate can be suppressed.
　半導体基板の表面荒れは、半導体基板の表面からランダムに抜き取った各部分における、算術平均粗さ（Ｒａ）、最大高さ（Ｒｙ）、十点平均粗さ（Ｒｚ）、凹凸の平均間隔（Ｓｍ）、局部山頂の平均間隔（Ｓ）の算術平均値又は負荷長さ率（ｔｐ）の算術平均値で評価することができる。具体的には、ＪＩＳ　Ｂ０６３３：２００１／ＩＳＯ　４２８８：１９９６に準拠して測定し、評価することができ、この中でも算術平均粗さ（Ｒａ）で評価することが好ましい。 The roughness of the surface of the semiconductor substrate is the arithmetic average roughness (Ra), maximum height (Ry), ten-point average roughness (Rz), and average interval of irregularities (Sm) in each part extracted at random from the surface of the semiconductor substrate. ), The arithmetic average value of the average interval (S) of the local peaks, or the arithmetic average value of the load length ratio (tp). Specifically, it can be measured and evaluated according to JIS B0633: 2001 / ISO 4288: 1996, and among these, it is preferable to evaluate by arithmetic mean roughness (Ra).
　得られた半導体基板の算術平均粗さ（Ｒａ）は、０．１μｍ以下であることが好ましく、０．０５μｍ以下であることがより好ましく、０．０１μｍ以下であることが更に好ましい。Ｒａが０．１μｍ以下であると、それを用いた太陽電池の特性が低下しにくい傾向にある。 The arithmetic average roughness (Ra) of the obtained semiconductor substrate is preferably 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.01 μm or less. When Ra is 0.1 μm or less, the characteristics of a solar cell using the same tend not to be deteriorated.
　バリア層形成用組成物の全不揮発成分中の、前記特定化合物の含有率は、０．５質量％以上５０質量％以下であることが好ましく、１質量％以上２５質量％以下であることがより好ましく、５質量％以上２０質量％以下であることが更に好ましい。 The content of the specific compound in all nonvolatile components of the barrier layer forming composition is preferably 0.5% by mass or more and 50% by mass or less, and more preferably 1% by mass or more and 25% by mass or less. Preferably, it is 5 mass% or more and 20 mass% or less.
〔金属アルコキシド〕
　金属アルコキシドは、特定金属原子とアルコールとが反応した化合物であり、下記一般式（１）で表されるものであることが好ましい。
　　　Ｍ（ＯＲ１）ａ　　　　　（１） [Metal alkoxide]
The metal alkoxide is a compound obtained by reacting a specific metal atom and an alcohol, and is preferably represented by the following general formula (1).
M (OR 1 ) a (1)
　式（１）中、Ｍは、Ｌｉ、Ｎａ、Ｋ、Ｍｇ、Ｃａ、Ｓｒ、Ｂａ、Ｌａ、Ｔｉ、Ｂ、Ｚｒ、Ｈｆ、Ｖ、Ｎｂ、Ｔａ、Ｃｒ、Ｍｏ、Ｗ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｐｂ及びＢｉから選択される金属を表しており、ａは、金属Ｍの価数に応じた１～７の正数であり、Ｒ１は、アルコールのＯＨ基を除いた残基である。 In formula (1), M is Li, Na, K, Mg, Ca, Sr, Ba, La, Ti, B, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co Represents a metal selected from Ni, Cu, Zn, Pb and Bi, a is a positive number from 1 to 7 depending on the valence of the metal M, and R 1 excludes the OH group of the alcohol Residue.
　上記金属アルコキシドを形成するアルコールとしては、例えば、下記式（２）に示すものを好適例として挙げることができる。 Examples of the alcohol that forms the metal alkoxide include those represented by the following formula (2).
　　Ｒ１ＯＨ　　　　　（２） R 1 OH (2)
　式（２）中、Ｒ１は、炭素原子数１～６の飽和若しくは不飽和の炭化水素基、又は炭素原子数１～６のアルコキシ基で置換された総炭素原子数２～２０の飽和若しくは不飽和の炭化水素基を示す。 In the formula (2), R 1 represents a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, or a saturated or saturated group having 2 to 20 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms. An unsaturated hydrocarbon group.
　上記一般式（２）において、Ｒ１で示される炭素原子数１～６の飽和又は不飽和の炭化水素基は、直鎖、分岐鎖状及び環状のいずれであってもよい。また、飽和の炭化水素基であることが好ましい。 In the above general formula (2), the saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms represented by R 1 may be linear, branched or cyclic. Moreover, it is preferable that it is a saturated hydrocarbon group.
　上記一般式（２）において、Ｒ１が炭素原子数１～６の飽和又は不飽和の炭化水素基の場合は、式（２）で示されるアルコールとしては、例えば、メタノール、エタノール、１－プロパノール、２－プロパノール、ブタノール、アミルアルコール、シクロヘキサノール等を挙げることができる。 In the general formula (2), when R 1 is a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, examples of the alcohol represented by the formula (2) include methanol, ethanol, 1-propanol 2-propanol, butanol, amyl alcohol, cyclohexanol and the like.
　また、上記一般式（２）において、Ｒ１で示される炭素原子数１～６のアルコキシ基で置換された総炭素原子数２～２０の飽和若しくは不飽和の炭化水素基の場合、直鎖、分岐鎖状及び環状のいずれの炭化水素基であってもよい。また、飽和の炭化水素基であることが好ましい。更に、アルコキシ基の置換数は、１～５であることが好ましく、１～４であることがより好ましく、１～３であることが更に好ましい。 In the general formula (2), in the case of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms substituted by an alkoxy group having 1 to 6 carbon atoms represented by R 1 , Either a branched or cyclic hydrocarbon group may be used. Moreover, it is preferable that it is a saturated hydrocarbon group. Furthermore, the number of alkoxy group substitutions is preferably 1 to 5, more preferably 1 to 4, and still more preferably 1 to 3.
　上記一般式（２）において、Ｒ１が炭素原子数１～６のアルコキシ基で置換された炭化水素基の場合は、式（２）で示されるアルコールとしては、例えば、メトキシメタノール、メトキシエタノール、エトキシメタノール、エトキシエタノール、メトキシプロパノール、エトキシプロパノール、プロポキシプロパノール等を挙げることができる。 In the general formula (2), when R 1 is a hydrocarbon group substituted with an alkoxy group having 1 to 6 carbon atoms, examples of the alcohol represented by the formula (2) include methoxymethanol, methoxyethanol, Examples thereof include ethoxymethanol, ethoxyethanol, methoxypropanol, ethoxypropanol, and propoxypropanol.
〔シリコンアルコキシド〕
　シリコンアルコキシドは、下記式（３）で表されるものであることが好ましい。 [Silicon alkoxide]
The silicon alkoxide is preferably represented by the following formula (3).
　　　　（Ｒ２）ｎＳｉ（ＯＲ３）４－ｎ　　　（３） (R 2 ) n Si (OR 3 ) 4-n (3)
　式（３）中、Ｒ２は、メチル基、フェニル基、ビニル基、エポキシ基、スチリル基、メタクリル基、アクリル基、アミノ基、ウレイド基、メルカプト基、スルフィド基又はイソシアネート基を表し、Ｒ３は、メチル基、エチル基又はプロピル基を表し、ｎは０～３を表す。 In formula (3), R 2 represents a methyl group, a phenyl group, a vinyl group, an epoxy group, a styryl group, a methacryl group, an acrylic group, an amino group, a ureido group, a mercapto group, a sulfide group or an isocyanate group, and R 3 Represents a methyl group, an ethyl group or a propyl group, and n represents 0 to 3.
　式（３）において、Ｒ２は、メチル基又はフェニル基であることが好ましく、Ｒ３は、メチル基又はエチル基であることが好ましい。ｎは０～２であることが好ましく、０又は１であることがより好ましく、０であることが更に好ましい。 In Formula (3), R 2 is preferably a methyl group or a phenyl group, and R 3 is preferably a methyl group or an ethyl group. n is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
　具体的には、シリコンアルコキシドとしては、テトラエトキシシラン、テトラメトキシシラン、メチルトリメトキシシラン及びメチルトリエトキシシランからなる群より選択される１種以上を用いることが好ましく、テトラエトキシシラン及びテトラメトキシシランからなる群より選択される１種以上を用いることがより好ましい。テトラエトキシシラン及びテトラメトキシシランは反応性に富んでいるため、半導体基板と特定アルカリ化合物との界面に酸化ケイ素層を形成しやすく、半導体基板の表面荒れを抑制しやすい。 Specifically, as the silicon alkoxide, it is preferable to use one or more selected from the group consisting of tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane, and tetraethoxysilane and tetramethoxysilane. It is more preferable to use one or more selected from the group consisting of Since tetraethoxysilane and tetramethoxysilane are rich in reactivity, it is easy to form a silicon oxide layer at the interface between the semiconductor substrate and the specific alkali compound, and to suppress surface roughness of the semiconductor substrate.
　金属アルコキシドとシリコンアルコキシドとを比較すると、半導体基板の表面荒れを抑制する観点からは、シリコンアルコキシドが好ましい。 When metal alkoxide and silicon alkoxide are compared, silicon alkoxide is preferable from the viewpoint of suppressing surface roughness of the semiconductor substrate.
〔シリケートオリゴマー、シリコーンオイル〕
　また、シリコンアルコキシドは一部重合されたシリケートオリゴマー又はシリコーンオイルの状態で使用してもよい。つまり、シリコンアルコキシドの加水分解及び重縮合が進行した状態で使用してもよい。 [Silicate oligomer, silicone oil]
Silicon alkoxide may be used in the form of a partially polymerized silicate oligomer or silicone oil. That is, you may use in the state which the hydrolysis and polycondensation of silicon alkoxide advanced.
　加水分解を進行させるため、必要により、水、触媒等を添加してもよい。触媒としては、塩酸、硝酸、硫酸、ホウ酸、リン酸、フッ化水素酸等の無機酸；及び蟻酸、酢酸、プロピオン酸、酪酸、オレイン酸、リノール酸、サリチル酸、安息香酸、フタル酸、蓚酸、乳酸、コハク酸等の有機酸；を例示することができる。また、触媒として、アンモニア、アミン等の塩基を加えてもよい。アルカリ土類金属又はアルカリ金属を含有する金属化合物が触媒としての機能を兼ねていてもよい。 In order to promote hydrolysis, water, a catalyst, etc. may be added as necessary. Catalysts include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, boric acid, phosphoric acid, hydrofluoric acid; and formic acid, acetic acid, propionic acid, butyric acid, oleic acid, linoleic acid, salicylic acid, benzoic acid, phthalic acid, oxalic acid And organic acids such as lactic acid and succinic acid. Moreover, you may add bases, such as ammonia and an amine, as a catalyst. An alkaline earth metal or a metal compound containing an alkali metal may also serve as a catalyst.
　ここでいうシリケートオリゴマーとは、シリコンアルコキシドを加水分解及び重縮合したＳｉｎＯｎ－１（ＯＲ）２（ｎ＋１）で表される化合物〔Ｒは、メチル基、エチル基又はプロピル基を示し、ｎは３～１０の整数を示す〕であることが好ましい。シリケートオリゴマーは、メタノール、エタノール、プロパノール、ブタノール等のアルコール系溶媒に溶解又は分散されていてもよい。 The silicate oligomer here is a compound represented by Si n O n-1 (OR) 2 (n + 1) obtained by hydrolysis and polycondensation of silicon alkoxide [R represents a methyl group, an ethyl group or a propyl group, n is preferably an integer of 3 to 10. The silicate oligomer may be dissolved or dispersed in an alcohol solvent such as methanol, ethanol, propanol, or butanol.
　このようなシリケートオリゴマー又はシリコーンオイルとしては、多摩化学工業株式会社製のシリケート（シリケート４０、シリケート４５、Ｍシリケート５１等）、コルコート株式会社製のシリケート（メチルシリケート５１、メチルシリケート５３Ａ、エチルシリケート４０、エチルシリケート４８）、ＥＭＳ－４８５のようなシリケートオリゴマー、ポリジメチルシロキサン等のメチルシリコーンオイル、メチルフェニルシリコーンオイル、メチルハイドロジェンシリコーンオイル、変性シリコーンオイル等のシリコーンオイル類が挙げられる。 Examples of such silicate oligomer or silicone oil include silicates manufactured by Tama Chemical Co., Ltd. (silicate 40, silicate 45, M silicate 51, etc.), and silicates manufactured by Colcoat Co., Ltd. (methyl silicate 51, methyl silicate 53A, ethyl silicate 40). Silicate oligomers such as ethyl silicate 48) and EMS-485, methyl silicone oils such as polydimethylsiloxane, silicone oils such as methylphenyl silicone oil, methyl hydrogen silicone oil, and modified silicone oil.
　これら特定化合物の中でも、シリコンアルコキシド、メチルシリケートオリゴマー及びエチルシリケートオリゴマーからなる群より選択される１種以上を含むことが、バリア性能を低下させることなく、表面荒れを抑制できる傾向にあることから好ましい。 Among these specific compounds, the inclusion of one or more selected from the group consisting of silicon alkoxide, methyl silicate oligomer and ethyl silicate oligomer is preferable because it tends to suppress surface roughness without reducing barrier performance. .
（分散媒）
　本発明のバリア層形成用組成物は分散媒を含有する。分散媒とは、組成物中において上記アルカリ土類金属又はアルカリ金属を含有する金属化合物を分散又は溶解させる媒体である。 (Dispersion medium)
The barrier layer forming composition of the present invention contains a dispersion medium. The dispersion medium is a medium in which the alkaline earth metal or the metal compound containing the alkali metal is dispersed or dissolved in the composition.
　前記溶剤としては、例えば、アセトン、メチルエチルケトン、メチル－ｎ－プロピルケトン、メチルイソプロピルケトン、メチル－ｎ－ブチルケトン、メチルイソブチルケトン、メチル－ｎ－ペンチルケトン、メチル－ｎ－ヘキシルケトン、ジエチルケトン、ジプロピルケトン、ジイソブチルケトン、トリメチルノナノン、シクロヘキサノン、シクロペンタノン、メチルシクロヘキサノン、２，４－ペンタンジオン、アセトニルアセトン等のケトン系溶剤；ジエチルエーテル、メチルエチルエーテル、メチル－ｎ－プロピルエーテル、ジイソプロピルエーテル、テトラヒドロフラン、メチルテトラヒドロフラン、ジオキサン、ジメチルジオキサン、エチレングリコールジメチルエーテル、エチレングリコールジエチルエーテル、エチレングリコールジ－ｎ－プロピルエーテル、エチレングリコールジブチルエーテル、ジエチレングリコールモノブチルエーテル、ジエチレングリコールジメチルエーテル、ジエチレングリコールジエチルエーテル、ジエチレングリコールメチルエチルエーテル、ジエチレングリコールメチル－ｎ－プロピルエーテル、ジエチレングリコールメチル－ｎ－ブチルエーテル、ジエチレングリコールジ－ｎ－プロピルエーテル、ジエチレングリコールジ－ｎ－ブチルエーテル、ジエチレングリコールメチル－ｎ－ヘキシルエーテル、トリエチレングリコールジメチルエーテル、トリエチレングリコールジエチルエーテル、トリエチレングリコールメチルエチルエーテル、トリエチレングリコールメチル－ｎ－ブチルエーテル、トリエチレングリコールジ－ｎ－ブチルエーテル、トリエチレングリコールメチル－ｎ－ヘキシルエーテル、テトラエチレングリコールジメチルエーテル、テトラエチレングリコールジエチルエーテル、テトラエチレングリコールメチルエチルエーテル、テトラエチレングリコールメチル－ｎ－ブチルエーテル、ジエチレングリコールジ－ｎ－ブチルエーテル、テトラエチレングリコールメチル－ｎ－ヘキシルエーテル、テトラエチレングリコールジ－ｎ－ブチルエーテル、プロピレングリコールジメチルエーテル、プロピレングリコールジエチルエーテル、プロピレングリコールジ－ｎ－プロピルエーテル、プロピレングリコールジブチルエーテル、ジプロピレングリコールジメチルエーテル、ジプロピレングリコールジエチルエーテル、ジプロピレングリコールメチルエチルエーテル、ジプロピレングリコールメチル－ｎ－ブチルエーテル、ジプロピレングリコールジ－ｎ－プロピルエーテル、ジプロピレングリコールジ－ｎ－ブチルエーテル、ジプロピレングリコールメチル－ｎ－ヘキシルエーテル、トリプロピレングリコールジメチルエーテル、トリプロピレングリコールジエチルエーテル、トリプロピレングリコールメチルエチルエーテル、トリプロピレングリコールメチル－ｎ－ブチルエーテル、トリプロピレングリコールジ－ｎ－ブチルエーテル、トリプロピレングリコールメチル－ｎ－ヘキシルエーテル、テトラプロピレングリコールジメチルエーテル、テトラプロピレングリコールジエチルエーテル、テトラプロピレングリコールメチルエチルエーテル、テトラプロピレングリコールメチル－ｎ－ブチルエーテル、テトラプロピレングリコールジ－ｎ－ブチルエーテル、テトラプロピレングリコールメチル－ｎ－ヘキシルエーテル、テトラプロピレングリコールジ－ｎ－ブチルエーテル等のエーテル系溶剤；酢酸メチル、酢酸エチル、酢酸ｎ－プロピル、酢酸イソプロピル、酢酸ｎ－ブチル、酢酸イソブチル、酢酸ｓｅｃ－ブチル、酢酸ｎ－ペンチル、酢酸ｓｅｃ－ペンチル、酢酸３－メトキシブチル、酢酸メチルペンチル、酢酸２－エチルブチル、酢酸２－エチルヘキシル、酢酸２－（２－ブトキシエトキシ）エチル、酢酸ベンジル、酢酸シクロヘキシル、酢酸メチルシクロヘキシル、酢酸ノニル、アセト酢酸メチル、アセト酢酸エチル、酢酸ジエチレングリコールメチルエーテル、酢酸ジエチレングリコールモノエチルエーテル、酢酸ジエチレングリコールモノ－ｎ－ブチルエーテル、酢酸ジプロピレングリコールメチルエーテル、酢酸ジプロピレングリコールエチルエーテル、ジ酢酸グリコール、酢酸メトキシトリグリコール、プロピオン酸エチル、プロピオン酸ｎ－ブチル、プロピオン酸イソアミル、シュウ酸ジエチル、シュウ酸ジ－ｎ－ブチル、乳酸メチル、乳酸エチル、乳酸ｎ－ブチル、乳酸ｎ－アミル、エチレングリコールメチルエーテルプロピオネート、エチレングリコールエチルエーテルプロピオネート、エチレングリコールメチルエーテルアセテート、エチレングリコールエチルエーテルアセテート、プロピレングリコールメチルエーテルアセテート、プロピレングリコールエチルエーテルアセテート、プロピレングリコールプロピルエーテルアセテート、γ－ブチロラクトン、γ－バレロラクトン等のエステル系溶剤；アセトニトリル、Ｎ－メチルピロリジノン、Ｎ－エチルピロリジノン、Ｎ－プロピルピロリジノン、Ｎ－ブチルピロリジノン、Ｎ－ヘキシルピロリジノン、Ｎ－シクロヘキシルピロリジノン、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミド、ジメチルスルホキシド等の非プロトン性極性溶剤；メタノール、エタノール、ｎ－プロパノール、イソプロパノール、ｎ－ブタノール、イソブタノール、ｓｅｃ－ブタノール、ｔ－ブタノール、ｎ－ペンタノール、イソペンタノール、２－メチルブタノール、ｓｅｃ－ペンタノール、ｔ－ペンタノール、３－メトキシブタノール、ｎ－ヘキサノール、２－メチルペンタノール、ｓｅｃ－ヘキサノール、２－エチルブタノール、ｓｅｃ－ヘプタノール、ｎ－オクタノール、２－エチルヘキサノール、ｓｅｃ－オクタノール、ｎ－ノニルアルコール、ｎ－デカノール、ｓｅｃ－ウンデシルアルコール、トリメチルノニルアルコール、ｓｅｃ－テトラデシルアルコール、ｓｅｃ－ヘプタデシルアルコール、フェノール、シクロヘキサノール、メチルシクロヘキサノール、ベンジルアルコール、イソボルニルシクロヘキサノール、エチレングリコール、１，２－プロピレングリコール、１，３－ブチレングリコール、ジエチレングリコール、ジプロピレングリコール、トリエチレングリコール、トリプロピレングリコール等のアルコール系溶剤；エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル（セロソルブ）、エチレングリコールモノフェニルエーテル、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノ－ｎ－ブチルエーテル、ジエチレングリコールモノ－ｎ－ヘキシルエーテル、エトキシトリグリコール、テトラエチレングリコールモノ－ｎ－ブチルエーテル、プロピレングリコールモノメチルエーテル、ジプロピレングリコールモノメチルエーテル、ジプロピレングリコールモノエチルエーテル、トリプロピレングリコールモノメチルエーテル等のグリコールモノエーテル系溶剤；α－テルピネン、α－テルピネオール、ミルセン、アロオシメン、リモネン、ジペンテン、α－ピネン、β－ピネン、ターピネオール、カルボン、オシメン、フェランドレン等のテルペン系溶剤、イソボルニルフェノール、１－イソプロピル－４－メチル－ビシクロ［２．２．２］オクタ－５－エン－２，３－ジカルボン酸無水物、及びｐ－メンテニルフェノール；が挙げられる。これらは１種類を単独で又は２種類以上を組み合わせて使用される。 Examples of the solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, methyl-n-pentyl ketone, methyl-n-hexyl ketone, diethyl ketone, Ketone solvents such as propyl ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone; diethyl ether, methyl ethyl ether, methyl-n-propyl ether, diisopropyl Ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol Cold di-n-propyl ether, ethylene glycol dibutyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl n-propyl ether, diethylene glycol methyl n-butyl ether, diethylene glycol di-n-propyl ether , Diethylene glycol di-n-butyl ether, diethylene glycol methyl-n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl n-butyl ether, triethylene glycol di- -Butyl ether, triethylene glycol methyl-n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol methyl n-butyl ether, diethylene glycol di-n-butyl ether, tetraethylene glycol Methyl-n-hexyl ether, tetraethylene glycol di-n-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, Dipropylene glycol methyl Ethyl ether, dipropylene glycol methyl-n-butyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl Ether, tripropylene glycol methyl ethyl ether, tripropylene glycol methyl-n-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl-n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetrapropylene Glycol methyl ethyl ether, tetrapropylene glycol methyl Ether solvents such as butyl ether, tetrapropylene glycol di-n-butyl ether, tetrapropylene glycol methyl-n-hexyl ether, tetrapropylene glycol di-n-butyl ether; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, N-butyl acetate, isobutyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2- (2-butoxy acetate) Ethoxy) ethyl, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate Diethylene glycol mono-n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, diacetic acid glycol, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, isoamyl propionate, diethyl oxalate, sulphate Di-n-butyl acid, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate , Propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate Ester solvents such as γ-butyrolactone and γ-valerolactone; acetonitrile, N-methylpyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N, Aprotic polar solvents such as N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide; methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, n-pen Tanol, isopentanol, 2-methylbutanol, sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutane Nord, sec-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, Such as phenol, cyclohexanol, methylcyclohexanol, benzyl alcohol, isobornylcyclohexanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, etc. Alcohol solvents; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether (cellosolve), ethylene glycol Nophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl Glycol monoether solvents such as ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether; α-terpinene, α-terpineol, myrcene, alloocimene, limonene, dipentene, α-pinene, β-pinene, terpineol, carvone, Terpene solvents such as osymene and ferrandrene, isobornylphenol, 1-isopropyl-4-methyl-bicyclo [2.2.2] oct-5-ene-2,3-dicarboxylic anhydride, and p-mentenyl phenol. These are used singly or in combination of two or more.
　これらの中でも、半導体基板への塗布性の観点から、分散媒としては、水、アルコール系溶剤、グリコールモノエーテル系溶剤、又はテルペン系溶剤が好ましく、水、アルコール、セロソルブ、α－テルピネオール、ジエチレングリコールモノ－ｎ－ブチルエーテル、又は酢酸ジエチレングリコールモノ－ｎ－ブチルエーテルが好ましく、水、アルコール、α－テルピネオール又はセロソルブが好ましい。 Among these, from the viewpoint of applicability to a semiconductor substrate, the dispersion medium is preferably water, an alcohol solvent, a glycol monoether solvent, or a terpene solvent, and is water, alcohol, cellosolve, α-terpineol, diethylene glycol monoester. N-Butyl ether or diethylene glycol mono-n-butyl ether is preferred, and water, alcohol, α-terpineol or cellosolve are preferred.
　バリア層形成用組成物中の分散媒の含有率は、塗布性、及びドーパント濃度を考慮し決定され、例えばバリア層形成用組成物において、５質量％以上９９質量％以下であることが好ましく、２０質量％以上９５質量％以下であることがより好ましく、４０質量％以上９０質量％以下であることが更に好ましい。 The content of the dispersion medium in the barrier layer forming composition is determined in consideration of the coating property and the dopant concentration. For example, in the barrier layer forming composition, the content is preferably 5% by mass or more and 99% by mass or less. It is more preferably 20% by mass or more and 95% by mass or less, and further preferably 40% by mass or more and 90% by mass or less.
（有機バインダ）
　本発明のバリア層形成用組成物は、有機バインダを含有することが好ましい。有機バインダを含有することで、高温下においてアルカリ土類金属又はアルカリ金属を含有する金属化合物同士を結着させ、また、アルカリ土類金属又はアルカリ金属を含有する金属化合物と半導体基板とを結着させることが容易となる。 (Organic binder)
The barrier layer-forming composition of the present invention preferably contains an organic binder. By containing the organic binder, the alkaline earth metal or the metal compound containing the alkali metal is bound to each other at a high temperature, and the alkaline earth metal or the metal compound containing the alkali metal is bound to the semiconductor substrate. It becomes easy to make.
　有機バインダとしては、例えば、ポリビニルアルコール；ポリアクリルアミド樹脂；ポリビニルアミド樹脂；ポリビニルピロリドン樹脂；ポリエチレンオキサイド樹脂；ポリスルホン樹脂；アクリルアミドアルキルスルホン樹脂；セルロースエーテル、カルボキシメチルセルロース、ヒドロキシエチルセルロース、エチルセルロース等のセルロース誘導体；ゼラチン、ゼラチン誘導体；澱粉、澱粉誘導体；アルギン酸ナトリウム類；キサンタン；グア、グア誘導体；スクレログルカン、スクレログルカン誘導体；トラガカント、トラガカント誘導体；デキストリン、デキストリン誘導体；（メタ）アクリル酸樹脂；アルキル（メタ）アクリレート樹脂、ジメチルアミノエチル（メタ）アクリレート樹脂等の（メタ）アクリル酸エステル樹脂；ブタジエン樹脂；スチレン樹脂；ブチラール樹脂；及びこれらの共重合体を適宜選択し得る。
　これらの中でも、分解性、及びスクリーン印刷した際の液ダレ防止の観点から、アクリル酸樹脂、ブチラール樹脂又はセルロース誘導体を含むことが好ましい。これらは１種類を単独で又は２種類以上を組み合わせて使用される。 Examples of the organic binder include polyvinyl alcohol; polyacrylamide resin; polyvinyl amide resin; polyvinyl pyrrolidone resin; polyethylene oxide resin; polysulfone resin; acrylamide alkyl sulfone resin; cellulose derivatives such as cellulose ether, carboxymethyl cellulose, hydroxyethyl cellulose, and ethyl cellulose; Starch, starch derivative; sodium alginate; xanthan; guar, gua derivative; scleroglucan, scleroglucan derivative; tragacanth, tragacanth derivative; dextrin, dextrin derivative; (meth) acrylic acid resin; alkyl (meth) (Meth) acrylic acid ester resins such as acrylate resins and dimethylaminoethyl (meth) acrylate resins; Tajien resin; a styrene resin; butyral resin; and may select these copolymers as appropriate.
Among these, it is preferable that an acrylic acid resin, a butyral resin, or a cellulose derivative is included from a viewpoint of decomposability and prevention of dripping at the time of screen printing. These are used singly or in combination of two or more.
　有機バインダの分子量は特に制限されず、組成物としての所望の粘度を鑑みて適宜調整することが望ましい。なお、有機バインダを含有する場合の含有率は、バリア層形成用組成物中で、０．５質量％以上３０質量％以下であることが好ましく、３質量％以上２５質量％以下であることがより好ましく、３質量％以上２０質量％以下であることが更に好ましい。 The molecular weight of the organic binder is not particularly limited, and it is desirable to adjust appropriately in view of the desired viscosity as the composition. In addition, it is preferable that the content rate in the case of containing an organic binder is 0.5 mass% or more and 30 mass% or less in the composition for barrier layer formation, and it is 3 mass% or more and 25 mass% or less. More preferably, it is 3 mass% or more and 20 mass% or less.
　また、アルカリ土類金属及びアルカリ金属を含有する金属化合物の総含有量と有機バインダの総含有量の質量比率（アルカリ土類金属及びアルカリ金属の金属化合物）／（有機バインダ）が、９９．９／０．１～０．１／９９．９であることが好ましく、９９／１～２０／８０であることがより好ましい。 Further, the mass ratio of the total content of the alkaline earth metal and the metal compound containing the alkali metal to the total content of the organic binder (alkaline earth metal and alkali metal metal compound) / (organic binder) is 99.9. /0.1 to 0.1 / 99.9 is preferable, and 99/1 to 20/80 is more preferable.
　なお、前記分散媒及び有機バインダとして、有機バインダが溶解した分散媒を用いてもよい。 Note that a dispersion medium in which an organic binder is dissolved may be used as the dispersion medium and the organic binder.
　なお、バリア層形成用組成物は、有機バインダと共に又は有機バインダに替わる材料として、溶剤として例示したイソボルニルシクロヘキサノールを用いてもよい。イソボルニルシクロヘキサノールは「テルソルブ ＭＴＰＨ」（日本テルペン化学社製、商品名）として商業的に入手可能である。イソボルニルシクロヘキサノールは沸点が３０８℃～３１８℃と高く、またバリア層から除去する際には、有機バインダのように焼成による脱脂処理を行うまでもなく、加熱により気化させることによって消失させることができる。 In addition, the composition for barrier layer formation may use isobornyl cyclohexanol exemplified as a solvent together with the organic binder or as a material replacing the organic binder. Isobornylcyclohexanol is commercially available as “Telsolve® MTPH” (trade name, manufactured by Nippon Terpene Chemical Co., Ltd.). Isobornylcyclohexanol has a high boiling point of 308 ° C to 318 ° C, and when it is removed from the barrier layer, it does not need to be degreased by firing like an organic binder, but must be vaporized by heating. Can do.
　バリア層形成用組成物がイソボルニルシクロヘキサノールを含有する場合、イソボルニルシクロヘキサノールの含有率は、バリア層形成用組成物の総質量中に０．５質量％～８５質量％であることが好ましく、１質量％～８０質量％であることがより好ましく、２質量％～８０質量％であることが更に好ましい。 When the composition for forming a barrier layer contains isobornylcyclohexanol, the content of isobornylcyclohexanol is 0.5% by mass to 85% by mass in the total mass of the composition for forming a barrier layer. It is preferably 1% by mass to 80% by mass, more preferably 2% by mass to 80% by mass.
（その他の成分）
　バリア層形成用組成物は、アルカリ土類金属又はアルカリ金属を含有する金属化合物と、分散媒と、金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物と、に加え、必要に応じて、その他の成分として、増粘剤、湿潤剤、界面活性剤、無機粉末、チキソ剤等の各種添加剤を含有してもよい。 (Other ingredients)
The composition for forming a barrier layer is one or more specific compounds selected from the group consisting of an alkaline earth metal or an alkali metal-containing metal compound, a dispersion medium, a metal alkoxide, a silicon alkoxide, a silicate oligomer, and a silicone oil. In addition to these, as necessary, various additives such as a thickener, a wetting agent, a surfactant, an inorganic powder, and a thixotropic agent may be contained as necessary.
　前記界面活性剤としては、ノニオン系界面活性剤、カチオン系界面活性剤、アニオン系界面活性剤等が挙げられる。中でも、半導体デバイスへの重金属等の不純物の持ち込みが少ないことからノニオン系界面活性剤又はカチオン系界面活性剤が好ましい。更にはノニオン系界面活性剤としてシリコン系界面活性剤、フッ素系界面活性剤及び炭化水素系界面活性剤が例示され、拡散等の加熱時に速やかに焼成されることから、炭化水素系界面活性剤が好ましい。 Examples of the surfactant include nonionic surfactants, cationic surfactants, and anionic surfactants. Among these, nonionic surfactants or cationic surfactants are preferable because impurities such as heavy metals are not brought into the semiconductor device. Furthermore, silicon surfactants, fluorine surfactants and hydrocarbon surfactants are exemplified as nonionic surfactants, and since they are rapidly baked during heating such as diffusion, hydrocarbon surfactants are preferable.
　炭化水素系界面活性剤としては、エチレンオキサイド－プロピレンオキサイドのブロック共重合体、アセチレングリコール化合物等が例示され、半導体デバイスの抵抗値のバラツキをより低減することから、アセチレングリコール化合物がより好ましい。 Examples of the hydrocarbon-based surfactant include ethylene oxide-propylene oxide block copolymers, acetylene glycol compounds, and the like, and acetylene glycol compounds are more preferable because variations in resistance values of semiconductor devices are further reduced.
　無機粉末としては、酸化ケイ素、窒化ケイ素、酸化ケイ素、炭化ケイ素等の粉末を例示することができる。 Examples of the inorganic powder include silicon oxide, silicon nitride, silicon oxide, silicon carbide powder and the like.
　バリア層形成用組成物は、チキソ剤を含有してもよい。これにより容易にチキソ性を制御することができ、スクリーン印刷に適切な粘度をもつスクリーン印刷用のバリア層形成用組成物、インクジェット印刷に適切な粘度をもつインクジェット用のバリア層形成用組成物を構成することができる。更にまた、チキソ性が制御されていることより、印刷時におけるバリア層形成用組成物の印刷パターンからの滲みやダレを抑制することができる。 The barrier layer forming composition may contain a thixotropic agent. Thus, a thixotropic property can be easily controlled, and a barrier layer forming composition for screen printing having a viscosity suitable for screen printing and a barrier layer forming composition for ink jet having a viscosity suitable for ink jet printing are provided. Can be configured. Furthermore, since the thixotropy is controlled, it is possible to suppress bleeding and sagging from the printed pattern of the barrier layer forming composition during printing.
　チキソ剤としては、ポリエーテル化合物、脂肪酸アミド、有機フィラー、無機フィラー、水素添加ひまし油、尿素ウレタンアミド、バイオガム、グアーガム、ローカストビーンガム、カラギナン、ペクチン、寒天、βグルカン、タマリンドシードガム、サイリウムシードガム、ポリビニルピロリドン、シリコーン系増粘ゲル化剤及びオイル系ゲル化剤（商品名：ゲルオール（新日本理化製））を例示することができる。
　前述の有機バインダがチキソ剤の役割を兼ねていてもよく、このような材料としてエチルセルロースを挙げることができる。 As thixotropic agents, polyether compounds, fatty acid amide, organic filler, inorganic filler, hydrogenated castor oil, urea urethane amide, bio gum, guar gum, locust bean gum, carrageenan, pectin, agar, β-glucan, tamarind seed gum, psyllium seed gum , Polyvinyl pyrrolidone, silicone-based thickening gelling agent and oil-based gelling agent (trade name: Gelol (manufactured by Nippon Nippon Chemical Co., Ltd.)).
The organic binder described above may also serve as a thixotropic agent. Examples of such a material include ethyl cellulose.
　本発明のバリア層形成用組成物は、半導体基板を汚染しない、つまり半導体基板中のキャリアの再結合を抑制する観点から、鉄、タングステン、金、ニッケル、クロム、マンガン等の含有率が、バリア層形成用組成物中で、１０質量％以下であることが好ましく、５質量％以下であることがより好ましく、１質量％以下であることが更に好ましい。 The composition for forming a barrier layer of the present invention does not contaminate the semiconductor substrate, that is, from the viewpoint of suppressing carrier recombination in the semiconductor substrate, the content of iron, tungsten, gold, nickel, chromium, manganese, etc. In the composition for layer formation, it is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 1% by mass or less.
　バリア層形成用組成物の粘度は特に制限はない。具体的には、２５℃において、Ｅ型粘度計にて、回転速度０．５ｒｐｍ～５ｒｐｍで測定した粘度が０．５Ｐａ・ｓ～４００Ｐａ・ｓであることが好ましく、４０Ｐａ・ｓ～２００Ｐａ・ｓであることがより好ましい。バリア層形成用組成物の粘度が０．５Ｐａ・ｓ以上であると半導体基板に塗布した際に液ダレが起き難く、また、４００Ｐａ・ｓ以下であると細かい塗布パターンを形成することが可能となる。 The viscosity of the barrier layer forming composition is not particularly limited. Specifically, the viscosity measured at 25 ° C. with an E-type viscometer at a rotational speed of 0.5 rpm to 5 rpm is preferably 0.5 Pa · s to 400 Pa · s, preferably 40 Pa · s to 200 Pa · s. It is more preferable that When the barrier layer forming composition has a viscosity of 0.5 Pa · s or more, liquid dripping hardly occurs when applied to a semiconductor substrate, and when it is 400 Pa · s or less, a fine coating pattern can be formed. Become.
　本発明のバリア層形成用組成物は、アルカリ土類金属又はアルカリ金属を含有する金属化合物と、分散媒と、金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物と、必要に応じて加えられる成分をブレンダー、ミキサ、乳鉢、又はローターを用いて混合することで得ることができる。また、混合する際は、必要に応じて熱を加えてもよい。このときの加熱温度は、例えば、３０℃～１００℃とすることができる。 The composition for forming a barrier layer of the present invention is one or more selected from the group consisting of an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, a metal alkoxide, a silicon alkoxide, a silicate oligomer, and a silicone oil. And a component added as necessary can be obtained by mixing using a blender, a mixer, a mortar, or a rotor. Moreover, when mixing, you may add a heat | fever as needed. The heating temperature at this time can be, for example, 30 ° C. to 100 ° C.
＜太陽電池用基板及び太陽電池素子の製造方法＞
　本発明の太陽電池用基板の製造方法は、前記バリア層形成用組成物を半導体基板上に付与してパターン状のバリア層を形成する工程と、前記半導体基板上の前記バリア層が形成されていない部分に、ドナー元素又はアクセプター元素を拡散して、前記半導体基板内に部分的に拡散層を形成する工程と、を含む。
　また、本発明の太陽電池素子の製造方法は、上記製造方法により得られる太陽電池用基板の拡散層上に、電極を形成する工程を含む。 <Method for Manufacturing Solar Cell Substrate and Solar Cell Element>
In the method for producing a solar cell substrate of the present invention, the barrier layer forming composition is formed on a semiconductor substrate to form a patterned barrier layer, and the barrier layer on the semiconductor substrate is formed. And a step of diffusing a donor element or an acceptor element in a portion where the diffusion layer is not formed to partially form a diffusion layer in the semiconductor substrate.
Moreover, the manufacturing method of the solar cell element of this invention includes the process of forming an electrode on the diffusion layer of the board | substrate for solar cells obtained by the said manufacturing method.
　ここで、本発明のバリア層形成用組成物を用いた太陽電池用基板及び太陽電池素子の製造方法について、図１を参照しながら説明する。図１は、本発明の太陽電池用基板及び太陽電池素子の製造工程の一例を概念的に表す模式断面図である。 Here, a method for manufacturing a solar cell substrate and a solar cell element using the barrier layer forming composition of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view conceptually showing an example of a manufacturing process of a solar cell substrate and a solar cell element of the present invention.
　なお、図１では裏面電極型の太陽電池用基板及び太陽電池素子について説明するが、本発明のバリア層形成用組成物はいずれの形式の太陽電池用基板及び太陽電池素子にも適用できる。
　裏面電極型以外のその他の形式としては、選択エミッタ型および両面受光型を例示することができる。選択エミッタ型の太陽電池用基板では、受光面側の電極直下に他の領域よりもドーパント濃度の高い拡散層が形成されている。この高濃度の拡散層の領域を形成するのに、本発明のバリア層形成用組成物を用いることができる。また、両面受光型の太陽電池素子では、両面に電極としてフィンガーバー及びバスバーが形成され、半導体基板の一方の面にはｎ＋型拡散層、他方の面にはｐ＋型拡散層が形成されている。このｎ＋型拡散層及びｐ＋型拡散層を位置選択的に形成するために、本発明のバリア層形成用組成物を用いることができる。 In addition, although FIG. 1 demonstrates a back electrode type solar cell substrate and a solar cell element, the composition for forming a barrier layer of the present invention can be applied to any type of solar cell substrate and solar cell element.
As other types other than the back electrode type, a selective emitter type and a double-sided light receiving type can be exemplified. In the selective emitter type solar cell substrate, a diffusion layer having a dopant concentration higher than that of other regions is formed immediately below the electrode on the light receiving surface side. The barrier layer forming composition of the present invention can be used to form the high concentration diffusion layer region. Also, in a double-sided light receiving solar cell element, finger bars and bus bars are formed on both surfaces as electrodes, an n + type diffusion layer is formed on one surface of the semiconductor substrate, and a p + type diffusion layer is formed on the other surface. ing. In order to selectively form the n + -type diffusion layer and the p + -type diffusion layer, the barrier layer forming composition of the present invention can be used.
　図１（１）では、ｎ型半導体基板１０であるシリコン基板にアルカリ溶液を付与してダメージ層を除去し、テクスチャー構造をエッチングにて得る。
　詳細には、インゴットからスライスした際に発生するシリコン基板表面のダメージ層を２０質量％苛性ソーダで除去する。次いで、１質量％苛性ソーダと１０質量％イソプロピルアルコールの混合液によりシリコン基板をエッチングし、ｎ型半導体基板１０にテクスチャー構造を形成する（図中ではテクスチャー構造の記載を省略する）。太陽電池素子は、ｎ型半導体基板１０の受光面（表面）側にテクスチャー構造を形成することにより、光閉じ込め効果が促され、高効率化が図られる。 In FIG. 1A, an alkaline solution is applied to a silicon substrate which is an n-type semiconductor substrate 10 to remove a damaged layer, and a texture structure is obtained by etching.
Specifically, the damaged layer on the surface of the silicon substrate generated when slicing from the ingot is removed with 20% by mass caustic soda. Next, the silicon substrate is etched with a mixed solution of 1% by mass caustic soda and 10% by mass isopropyl alcohol to form a texture structure on the n-type semiconductor substrate 10 (the description of the texture structure is omitted in the figure). In the solar cell element, by forming a texture structure on the light-receiving surface (front surface) side of the n-type semiconductor substrate 10, a light confinement effect is promoted, and high efficiency is achieved.
　図１（２）では、ｎ型半導体基板１０の表面（すなわち受光面）及び該受光面とは反対面である裏面に、本発明のバリア層形成用組成物１１を付与する。本発明では、付与方法には制限が無く、印刷法、スピン法、刷毛塗り、スプレー法、ドクターブレード法、ロールコーター法、インクジェット法等が挙げられ、印刷法又はインクジェット法を用いることが好ましい。
　上記バリア層形成用組成物の付与量としては特に制限は無く、０．０１ｇ／ｍ２以上１００ｇ／ｍ２以下とすることが好ましく、０．１ｇ／ｍ２以上２０ｇ／ｍ２以下であることがより好ましい。上記バリア層形成用組成物の塗布厚さに特に制限は無く、０．１μｍ以上５０μｍ以下であることが好ましく、１μｍ以上３０μｍ以下ｄであることがより好ましい。 In FIG. 1 (2), the barrier layer forming composition 11 of the present invention is applied to the front surface (that is, the light receiving surface) of the n-type semiconductor substrate 10 and the back surface opposite to the light receiving surface. In the present invention, the application method is not limited, and examples thereof include a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method, and it is preferable to use a printing method or an ink jet method.
There is no particular limitation as application amount of the composition for forming a barrier layer, it is possible to 0.01 g / m 2 or more 100 g / m 2 or less and preferably, 0.1 g / m 2 or more 20 g / m 2 or less Is more preferable. There is no restriction | limiting in particular in the coating thickness of the said composition for barrier layer formation, It is preferable that they are 0.1 micrometer or more and 50 micrometers or less, and it is more preferable that they are 1 micrometer or more and 30 micrometers or less d.
　また、バリア層形成用組成物の組成によっては、付与後に、組成物中に含まれる分散媒を揮発させるための乾燥工程が必要な場合がある。この場合には、８０℃～３００℃程度の温度で、ホットプレートを使用する場合は１分～１０分、乾燥機等を用いる場合は１０分～３０分程度で乾燥させる。この乾燥条件は、バリア層形成用組成物の分散媒の含有量に依存しており、本発明では特に上記条件に限定されない。この場合、バリア層は、バリア層形成用組成物を乾燥した乾燥体として得ることができる。 Depending on the composition of the barrier layer forming composition, a drying step for volatilizing the dispersion medium contained in the composition may be necessary after application. In this case, drying is performed at a temperature of about 80 ° C. to 300 ° C. for about 1 to 10 minutes when using a hot plate, and about 10 to 30 minutes when using a dryer or the like. This drying condition depends on the content of the dispersion medium of the barrier layer forming composition and is not particularly limited to the above condition in the present invention. In this case, the barrier layer can be obtained as a dried product obtained by drying the barrier layer forming composition.
　なお、パターン状のバリア層は、印刷法、インクジェット法等の場合には、バリア層形成用組成物１１をパターン状に付与することで得られる。一方、スピン法、刷毛塗り、スプレー法、ドクターブレード法、ロールコーター法等の場合には、バリア層形成用組成物１１を全面に塗布した後、エッチング等により部分的に除去することでパターン状のバリア層が得られる。 The patterned barrier layer can be obtained by applying the barrier layer forming composition 11 in a pattern in the case of a printing method, an inkjet method or the like. On the other hand, in the case of the spin method, brush coating, spray method, doctor blade method, roll coater method, etc., after the barrier layer forming composition 11 is applied to the entire surface, it is partially removed by etching or the like. The barrier layer is obtained.
　次いで、図１（３）では、ｎ＋型拡散層及びｐ＋型拡散層を形成するための塗布用拡散材料１２、１３を塗布する。次いで、図１（４）では、熱拡散して、ｎ型半導体基板１０にｎ＋型拡散層１４、ｐ＋型拡散層１５を形成する。熱拡散のための熱処理により、塗布用拡散材料１２、１３は塗布用拡散材料の焼成物１２’、１３’となり、一般にはガラス層を形成する。熱拡散するための熱処理温度としては特に制限はないが、７５０℃～１０５０℃の温度で１分～３００分間の条件で熱処理することが好ましい。 Next, in FIG. 1C, coating diffusion materials 12 and 13 for forming an n + type diffusion layer and a p + type diffusion layer are applied. Next, in FIG. 1 (4), an n + -type diffusion layer 14 and a p + -type diffusion layer 15 are formed on the n-type semiconductor substrate 10 by thermal diffusion. By the heat treatment for thermal diffusion, the coating diffusion materials 12 and 13 become the fired products 12 ′ and 13 ′ of the coating diffusion material and generally form a glass layer. The heat treatment temperature for thermal diffusion is not particularly limited, but the heat treatment is preferably performed at a temperature of 750 ° C. to 1050 ° C. for 1 minute to 300 minutes.
　ここではｎ＋型拡散層１４とｐ＋型拡散層１５を同時に形成する方法を図示したが、個別に拡散してもよい。つまり、まずｐ＋型拡散層１５を形成するための塗布用拡散材料１３を塗布し熱拡散させ、塗布用拡散材料の焼成物１３’を除去した後に、ｎ＋型拡散層１４を形成するための塗布用拡散材料１２を塗布し熱拡散させ、塗布用拡散材料の焼成物１２’を除去してもよい。 Here, a method of forming the n + -type diffusion layer 14 and the p + -type diffusion layer 15 at the same time is illustrated, but they may be diffused individually. That is, first, the coating diffusion material 13 for forming the p + -type diffusion layer 15 is applied and thermally diffused to remove the fired product 13 ′ of the coating diffusion material, and then the n + -type diffusion layer 14 is formed. The coating diffusion material 12 may be applied and thermally diffused to remove the fired product 12 'of the coating diffusion material.
　また、ここでは塗布用拡散材料１２、１３を用いた場合について説明したが、ＰＯＣｌ３ガスやＢＢｒ３ガスを用いた方法にも同様に適用できる。その場合、まずｎ型半導体基板１０においてｐ＋型拡散層１５を形成する予定の領域を開口部とし、その開口部とする領域以外にバリア層形成用組成物によりバリア層を形成する。そして、その開口部に対応するｎ型半導体基板１０にｐ＋型拡散層１５を形成した後、バリア層を除去する。次いで、ｎ＋型拡散層１４を形成する予定の領域を開口部とし、その開口部とする領域以外にバリア層形成用組成物によりバリア層を形成する。そして、その開口部に対応するｎ型半導体基板１０にｎ＋型拡散層１４を形成する。 Although the case where the coating diffusion materials 12 and 13 are used has been described here, the present invention can be similarly applied to a method using POCl 3 gas or BBr 3 gas. In that case, first, in the n-type semiconductor substrate 10, a region where the p + -type diffusion layer 15 is to be formed is used as an opening, and a barrier layer is formed using the barrier layer forming composition other than the region used as the opening. Then, after forming the p + -type diffusion layer 15 in the n-type semiconductor substrate 10 corresponding to the opening, the barrier layer is removed. Next, a region where the n + -type diffusion layer 14 is to be formed is used as an opening, and a barrier layer is formed using the barrier layer forming composition other than the region used as the opening. Then, an n + type diffusion layer 14 is formed in the n type semiconductor substrate 10 corresponding to the opening.
　次いで、図１（５）ではバリア層形成用組成物１１、及び塗布用拡散材料の焼成物１２’、１３’を除去して、太陽電池用基板を得る。前記除去方法としては、酸を含む水溶液に浸漬する等の方法が挙げられ、バリア層形成用組成物１１、及びｎ＋型拡散層１４及びｐ＋型拡散層１５を形成するための塗布用拡散材料の焼成物１２’、１３’の組成によって決定することが好ましい。具体的には、フッ酸を含む水溶液によって、熱拡散処理によって半導体基板上に生成したガラス層をエッチングする工程を含むことが好ましい。更に具体的には、アルカリ土類金属又はアルカリ金属を含有する金属化合物を塩酸（例えば１０質量％のＨＣｌ水溶液）によって除去した後、水洗し、更にフッ酸水溶液（例えば２．５質量％のＨＦ水溶液）によって塗布用拡散材料の焼成物１２’、１３’をエッチングした後、水洗する方法が挙げられる。 Next, in FIG. 1 (5), the barrier layer forming composition 11 and the fired products 12 ′ and 13 ′ of the diffusion material for coating are removed to obtain a solar cell substrate. Examples of the removal method include a method of immersing in an aqueous solution containing an acid, and a diffusion for coating for forming the barrier layer forming composition 11, and the n + type diffusion layer 14 and the p + type diffusion layer 15. It is preferably determined by the composition of the fired product 12 ', 13' of the material. Specifically, it is preferable to include a step of etching a glass layer formed on the semiconductor substrate by a thermal diffusion treatment with an aqueous solution containing hydrofluoric acid. More specifically, an alkaline earth metal or a metal compound containing an alkali metal is removed with hydrochloric acid (for example, 10% by mass HCl aqueous solution), washed with water, and further hydrofluoric acid aqueous solution (for example 2.5% by mass HF). An example is a method in which the fired products 12 ′ and 13 ′ of the diffusion material for coating are etched with an aqueous solution and then washed with water.
　次いで、図１（６）では、受光面である表面に反射防止膜１６、裏面にパッシベーション膜１７を付与する。反射防止膜１６とパッシベーション膜１７とは、組成が同じであっても異なっていてもよい。反射防止膜１６としては、例えば、窒化ケイ素膜が挙げられ、パッシベーション膜１７としては、例えば、酸化珪素膜が挙げられる。反射防止膜及びパッシベーション膜の膜厚に特に制限は無く、１０ｎｍ～３００ｎｍとすることが好ましく、３０ｎｍ～１５０ｎｍとすることがより好ましい。 Next, in FIG. 1 (6), an antireflection film 16 is provided on the front surface which is a light receiving surface, and a passivation film 17 is provided on the back surface. The antireflection film 16 and the passivation film 17 may have the same composition or different compositions. Examples of the antireflection film 16 include a silicon nitride film, and examples of the passivation film 17 include a silicon oxide film. The thickness of the antireflection film and the passivation film is not particularly limited, and is preferably 10 nm to 300 nm, and more preferably 30 nm to 150 nm.
　次いで、図１（７）では、パッシベーション膜１７に、電極を形成する箇所を開口する。開口する方法に特に制限はなく、例えば、開口したい箇所にエッチング液（例えばフッ酸、フッ化アンモニウム又はリン酸を含む溶液）をインクジェット法等で塗布し、熱処理することで開口することができる。 Next, in FIG. 1 (7), a portion for forming an electrode is opened in the passivation film 17. There is no particular limitation on the method of opening, and for example, the opening can be formed by applying an etching solution (for example, a solution containing hydrofluoric acid, ammonium fluoride, or phosphoric acid) to a portion where the opening is desired by an inkjet method or the like, and performing heat treatment.
　次いで、図１（８）ではｎ＋型拡散層１４、及びｐ＋型拡散層１５の上に、それぞれｎ電極１８及びｐ電極１９を形成する。本発明ではｎ電極１８及びｐ電極１９の材質や形成方法は特に限定されない。例えば、アルミニウム、銀、又は銅の金属を含む電極形成用ペーストを塗布し、乾燥させて、ｎ電極１８及びｐ電極１９を形成してもよい。次いで、ｎ電極１８及びｐ電極１９を焼成して、太陽電池素子を完成させる。 Next, in FIG. 1 (8), an n electrode 18 and a p electrode 19 are formed on the n + type diffusion layer 14 and the p + type diffusion layer 15, respectively. In the present invention, the material and forming method of the n electrode 18 and the p electrode 19 are not particularly limited. For example, the n-electrode 18 and the p-electrode 19 may be formed by applying an electrode forming paste containing aluminum, silver, or copper metal and drying the paste. Next, the n electrode 18 and the p electrode 19 are fired to complete the solar cell element.
　なお、前記電極形成用ペーストとしてガラスフリットを含むものを用いると、図１（７）で示した開口の工程を省略することが可能である。ガラスフリットを含む電極形成用ペーストをパッシベーション膜１７上に塗布し、６００℃～９００℃の範囲で数秒～数分間焼成すると、ガラスフリットが裏面側のパッシベーション膜１７を溶融し、ペースト中の金属粒子（例えば銀粒子）がシリコン基板１０と接触部を形成し凝固する。これにより、形成した表面電極１８、１９とシリコン基板１０とが導通される。これはファイアースルーと称されている。 In addition, if the paste containing glass frit is used as the electrode forming paste, the step of opening shown in FIG. 1 (7) can be omitted. When an electrode forming paste containing glass frit is applied on the passivation film 17 and baked for several seconds to several minutes in the range of 600 ° C. to 900 ° C., the glass frit melts the passivation film 17 on the back side, and the metal particles in the paste (For example, silver particles) form a contact portion with the silicon substrate 10 and solidify. Thereby, the formed surface electrodes 18 and 19 and the silicon substrate 10 are electrically connected. This is called fire-through.
＜太陽電池＞
　太陽電池は、前記太陽電池素子の１種以上を含み、太陽電池素子の電極上に配線材料が配置されて構成される。太陽電池は更に必要に応じて、配線材料を介して複数の太陽電池素子が連結され、更に封止材で封止されていてもよい。
　前記配線材料及び封止材としては特に制限されず、当業界で通常用いられているものから適宜選択することができる。 <Solar cell>
The solar cell includes one or more of the solar cell elements, and is configured by arranging a wiring material on the electrode of the solar cell element. In the solar cell, a plurality of solar cell elements may be connected via a wiring material as necessary, and may be further sealed with a sealing material.
The wiring material and the sealing material are not particularly limited, and can be appropriately selected from those usually used in the industry.
　なお、日本出願２０１２－００２６３３の開示はその全体が参照により本明細書に取り込まれる。
　本明細書に記載された全ての文献、特許出願、および技術規格は、個々の文献、特許出願、および技術規格が参照により取り込まれることが具体的かつ個々に記された場合と同程度に、本明細書中に参照により取り込まれる。 The entire disclosure of Japanese application 2012-002633 is incorporated herein by reference.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.
　以下、本発明の実施例を更に具体的に説明するが、本発明はこれらの実施例に制限するものではない。なお、特に記述が無い限り、薬品は全て試薬を使用した。また「％」は断りがない限り「質量％」を意味する。
　また、実施例中のアルカリ土類金属又はアルカリ金属を含有する金属化合物の体積平均粒子径はレーザー回折散乱法粒度径分布測定装置（ベックマン・コールター製ＬＳ　１３　３２０）を用い、分散状態で粒子径を測定した。 Examples of the present invention will be described more specifically below, but the present invention is not limited to these examples. Unless otherwise stated, all chemicals used reagents. “%” Means “% by mass” unless otherwise specified.
In addition, the volume average particle size of the alkaline earth metal or the metal compound containing the alkali metal in the examples is measured using a laser diffraction scattering method particle size distribution analyzer (LS 13 320 manufactured by Beckman Coulter), and the particle size in a dispersed state. Was measured.
＜実施例１＞
（バリア層形成用組成物１の調製）
　酸化カルシウム（宇部マテリアルズ製「ＣＳＱ」、体積平均粒子径１５．０μｍ、不定形粒子）１０ｇ（１８質量％）、テトラエトキシシラン（多摩化学工業製「正珪酸エチル」）１０ｇ、純水１．２５ｇ、及びブチルカルビトール（和光純薬工業製）８．７５ｇをジルコニア製ポットに入れた。更に、ジルコニア製ポットに３ｍｍのビーズミルを５０ｇ入れ、遊星型ボールミル（フリッチュ社製「ｐｕｌｖｅｒｉｓｅｔｔｅ」）を用い、６００ｒｐｍにて３０分間分散処理し、分散液を得た。 <Example 1>
(Preparation of composition 1 for forming a barrier layer)
10 g (18% by mass) of calcium oxide (“CSQ” manufactured by Ube Materials, volume average particle diameter of 15.0 μm, amorphous particles), 10 g of tetraethoxysilane (“Taka Kagaku Kogyo”, “normal ethyl silicate”), pure water 25 g and 8.75 g of butyl carbitol (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a zirconia pot. Further, 50 g of a 3 mm bead mill was put in a zirconia pot, and a dispersion was obtained using a planetary ball mill (“pulverisete” manufactured by Fritsch) for 30 minutes at 600 rpm.
　ついで、この分散液１５ｇと１５質量％のエチルセルロース（ダウケミカル製、ＳＴＤ２００）を溶解したテルピネオール（テルペン化学製「ターピネオール－ＬＷ」）１０ｇを、自転公転ミキサー（シンキー製「ＡＲ－１００」）を用いて混合し、バリア層形成組成物１を調製した。 Next, 10 g of terpineol (Terpineol-LW, manufactured by Terpene Chemical) in which 15 g of this dispersion and 15% by mass of ethylcellulose (manufactured by Dow Chemical Co., Ltd., STD200) were dissolved was used with a rotating / revolving mixer (“AR-100” manufactured by Sinky). To prepare a barrier layer forming composition 1.
　このバリア層形成用組成物１の２５℃、５ｒｐｍにおける粘度は４５Ｐａ・ｓであった。粘度は、Ｅ型粘度計（東京計器製）を用い、バリア層形成用組成物のサンプリング量を０．５ｍｌとして、測定した。 The viscosity of this composition 1 for forming a barrier layer 1 at 25 ° C. and 5 rpm was 45 Pa · s. The viscosity was measured using an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) with the sampling amount of the barrier layer forming composition being 0.5 ml.
（リン拡散液の調製）
　リン酸二水素アンモニウム（和光純薬工業製）の２０質量％水溶液を調製し、上澄みの飽和リン酸二水素アンモニウム水溶液をリン拡散液として用いた。 (Preparation of phosphorus diffusion solution)
A 20% by mass aqueous solution of ammonium dihydrogen phosphate (manufactured by Wako Pure Chemical Industries, Ltd.) was prepared, and a saturated aqueous solution of ammonium dihydrogen phosphate as a supernatant was used as the phosphorus diffusion solution.
（熱拡散及びエッチング工程）
　テクスチャー処理したｎ型シリコン基板（以下、「ｎ型シリコン基板」ともいう）表面上に、スクリーン印刷（ＭＴ－３２０Ｔ、マイクロテック製）によってバリア層形成用組成物１を塗布し、１５０℃のホットプレート上で５分間乾燥後、５００℃のホットプレートで１分間乾燥させた。これをバリア層付き基板とする。
　次いで、別のシリコン基板を用意し、リン拡散液を５００ｒｐｍでスピンコート（ミカサ社製、ＭＳ－Ａ１００）し、２００℃にて乾燥した。これを対向拡散用基板とする。 (Thermal diffusion and etching process)
On the surface of the textured n-type silicon substrate (hereinafter also referred to as “n-type silicon substrate”), the barrier layer-forming composition 1 was applied by screen printing (MT-320T, manufactured by Microtech) and heated at 150 ° C. After drying on the plate for 5 minutes, it was dried on a hot plate at 500 ° C. for 1 minute. This is a substrate with a barrier layer.
Next, another silicon substrate was prepared, and a phosphorus diffusion solution was spin-coated at 500 rpm (MS-A100, manufactured by Mikasa) and dried at 200 ° C. This is a counter diffusion substrate.
　バリア層付き基板と対向拡散用基板とを距離１ｍｍで対向させた状態で、９５０℃で１０分間加熱し、バリア層付き基板にリンを拡散させた。その後、バリア層付き基板を１０質量％ＨＣｌ水溶液に５分間浸漬した後、水洗し、更に２．５質量％ＨＦ水溶液に５分間浸漬した。これを水洗して、乾燥した後、下記評価を行った。 The substrate with the barrier layer and the counter diffusion substrate were opposed to each other at a distance of 1 mm, and heated at 950 ° C. for 10 minutes to diffuse phosphorus into the substrate with the barrier layer. Thereafter, the substrate with the barrier layer was immersed in a 10% by mass HCl aqueous solution for 5 minutes, washed with water, and further immersed in a 2.5% by mass HF aqueous solution for 5 minutes. This was washed with water and dried, and then evaluated as follows.
（シート抵抗の測定）
　バリア層形成用組成物１を塗布した部分の基板のシート抵抗は、三菱化学（株）製Ｌｏｒｅｓｔａ－ＥＰ　ＭＣＰ－Ｔ３６０型低抵抗率計を用いて四探針法により測定した。バリア層形成用組成物１を塗布した部分のシート抵抗は２４０Ω／□であった。塗布しない部分のシート抵抗は４０Ω／□であった。 (Sheet resistance measurement)
The sheet resistance of the substrate to which the barrier layer forming composition 1 was applied was measured by a four-probe method using a Loresta-EP MCP-T360 type low resistivity meter manufactured by Mitsubishi Chemical Corporation. The sheet resistance of the portion to which the barrier layer forming composition 1 was applied was 240Ω / □. The sheet resistance of the uncoated part was 40Ω / □.
　なお、参照試料として、スライス後のｎ型シリコン基板を２．５質量％ＨＦ水溶液に５分間浸漬し、これを水洗して、乾燥した後のシート抵抗を測定したところ、２４０Ω／□であった。 As a reference sample, the n-type silicon substrate after slicing was immersed in a 2.5% by mass HF aqueous solution for 5 minutes, washed with water, and measured for sheet resistance after drying, which was 240Ω / □. .
（表面粗さの測定）
　バリア層を塗布していた部分の表面粗さを、表面粗さ測定装置（株式会社ミツトヨ製、サーフテスト「ＳＪ－２１００」を用いて測定した。平均表面粗さＲａは０．０１μｍ以下であった。ここで、表面粗さは、テクスチャー構造のピラミッド形状の一面について測定を行った。 (Measurement of surface roughness)
The surface roughness of the portion where the barrier layer was applied was measured using a surface roughness measuring device (manufactured by Mitutoyo Corporation, Surf Test “SJ-2100”. The average surface roughness Ra was 0.01 μm or less. Here, the surface roughness was measured on one side of the pyramid shape of the texture structure.
＜実施例２～１１、比較例１、２＞
　表１及び２に示す組成のバリア層形成組成物を調製し、実施例１と同様にして評価した。結果を表１及び２に示す。なお、表１及び２中に示した材料は、以下の通りである。なお、表中「－」は添加していないことを示す。
　炭酸カルシウム：宇部マテリアル製
　炭酸マグネシウム：和光純薬工業製、体積平均粒子径８．９μｍ
　酸化マグネシウム：タテホ化学工業製、体積平均粒子径２．４μｍ
　シリケート４０：多摩化学工業製
　チタンイソプロポキシド：和光純薬工業製
　アセチルアセトン：和光純薬工業製
　ジルコニウムイソプロポキシド：和光純薬工業製
　ポリエチレングリコール：日油製、数平均分子量２００００
　ＭＲ－２Ｇ：総研化学社製、中実（密実）白色樹脂粒子、平均粒子径１．０μｍ
　シリコーンオイル：信越化学工業製、ジメチルシリコーンオイル、ＫＦ－９６ <Examples 2 to 11, Comparative Examples 1 and 2>
Barrier layer forming compositions having the compositions shown in Tables 1 and 2 were prepared and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2. The materials shown in Tables 1 and 2 are as follows. In the table, “-” indicates that no addition was made.
Calcium carbonate: manufactured by Ube Material Magnesium carbonate: manufactured by Wako Pure Chemical Industries, Ltd., volume average particle size 8.9 μm
Magnesium oxide: manufactured by Tateho Chemical Co., Ltd., volume average particle size 2.4 μm
Silicate 40: Tama Chemical Industries Titanium Isopropoxide: Wako Pure Chemical Industries Acetylacetone: Wako Pure Chemical Industries Zirconium Isopropoxide: Wako Pure Chemical Industries Polyethylene glycol: NOF Corporation, number average molecular weight 20000
MR-2G: manufactured by Soken Chemical Co., Ltd., solid (solid) white resin particles, average particle size 1.0 μm
Silicone oil: Shin-Etsu Chemical Co., Ltd., dimethyl silicone oil, KF-96
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　以上より、アルカリ土類金属又はアルカリ金属を含有する金属化合物と、分散媒と、金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物と、を含有するバリア層形成用組成物を用いることで、ドーパントの半導体基板への拡散を充分に防ぐことができ、また、バリア層を形成した箇所の半導体基板表面の荒れの発生を抑制できることが分かった。 As described above, it contains an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, and one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils. It has been found that by using the barrier layer forming composition, it is possible to sufficiently prevent the dopant from diffusing into the semiconductor substrate and to suppress the occurrence of roughness on the surface of the semiconductor substrate where the barrier layer is formed.

Claims (21)

  1. 　アルカリ土類金属又はアルカリ金属を含有する金属化合物と、分散媒と、金属アルコキシド、シリコンアルコキシド、シリケートオリゴマー及びシリコーンオイルからなる群より選択される１種以上の特定化合物と、を含有する、バリア層形成用組成物。 A barrier layer containing an alkaline earth metal or a metal compound containing an alkali metal, a dispersion medium, and one or more specific compounds selected from the group consisting of metal alkoxides, silicon alkoxides, silicate oligomers, and silicone oils Forming composition.
  2. 　前記特定化合物が、シリコンアルコキシド、メチルシリケートオリゴマー及びエチルシリケートオリゴマーからなる群より選択される１種以上を含む、請求項１に記載のバリア層形成用組成物。 The composition for forming a barrier layer according to claim 1, wherein the specific compound comprises one or more selected from the group consisting of silicon alkoxide, methyl silicate oligomer and ethyl silicate oligomer.
  3. 　前記特定化合物がシリコンアルコキシドを含み、前記シリコンアルコキシドが、テトラメトキシシラン及びテトラエトキシシランからなる群より選択される１種以上を含む、請求項１又は請求項２に記載のバリア層形成用組成物。 The composition for forming a barrier layer according to claim 1 or 2, wherein the specific compound includes silicon alkoxide, and the silicon alkoxide includes one or more selected from the group consisting of tetramethoxysilane and tetraethoxysilane. .
  4. 　不揮発成分中の、前記特定化合物の含有率が０．５質量％以上５０質量％以下である、請求項１～請求項３のいずれか１項に記載のバリア層形成用組成物。 The composition for forming a barrier layer according to any one of claims 1 to 3, wherein a content of the specific compound in the nonvolatile component is 0.5 mass% or more and 50 mass% or less.
  5. 　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、金属元素として、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される１種以上を含む、請求項１～請求項４のいずれか１項に記載のバリア層形成用組成物。 The alkaline earth metal or the metal compound containing an alkali metal is at least one selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium as the metal element The composition for forming a barrier layer according to any one of claims 1 to 4, comprising:
  6. 　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、酸化マグネシウム、酸化カルシウム、酸化カリウム、炭酸マグネシウム、炭酸カルシウム、硫酸マグネシウム、硫酸カルシウム、硝酸カルシウム、ステアリン酸カルシウム、水酸化マグネシウム及び水酸化カルシウムからなる群より選択される１種以上を含む、請求項１～請求項５のいずれか１項に記載のバリア層形成用組成物。 The alkaline earth metal or the metal compound containing an alkali metal is magnesium oxide, calcium oxide, potassium oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, calcium sulfate, calcium nitrate, calcium stearate, magnesium hydroxide, and calcium hydroxide. The composition for forming a barrier layer according to any one of claims 1 to 5, comprising at least one selected from the group consisting of:
  7. 　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、常温で固体の粒子であり、前記粒子の体積平均粒子径が３０μｍ以下である、請求項１～請求項６のいずれか１項に記載のバリア層形成用組成物。 The alkaline earth metal or the metal compound containing an alkali metal is a solid particle at normal temperature, and the volume average particle diameter of the particle is 30 μm or less. A barrier layer forming composition.
  8. 　更に有機バインダを含む、請求項１～請求項７のいずれか１項に記載のバリア層形成用組成物。 The barrier layer forming composition according to any one of claims 1 to 7, further comprising an organic binder.
  9. 　前記有機バインダが、アクリル樹脂、ブチラール樹脂及びセルロース樹脂からなる群より選択される１種以上を含む、請求項８に記載のバリア層形成用組成物。 The composition for forming a barrier layer according to claim 8, wherein the organic binder contains one or more selected from the group consisting of an acrylic resin, a butyral resin, and a cellulose resin.
  10. 　前記分散媒が、水、アルコール系溶剤、エーテル系溶剤、グリコールモノエーテル系溶剤及びテルペン系溶剤からなる群より選択される１種以上を含む、請求項１～請求項９のいずれか１項に記載のバリア層形成用組成物。 10. The dispersion medium according to claim 1, wherein the dispersion medium includes one or more selected from the group consisting of water, alcohol solvents, ether solvents, glycol monoether solvents, and terpene solvents. The composition for forming a barrier layer as described.
  11. 　不揮発成分中の、前記アルカリ土類金属又はアルカリ金属を含有する金属化合物の含有率が、０．５質量％以上１００質量％未満である、請求項１～請求項１０のいずれか１項に記載のバリア層形成用組成物。 The content of the alkaline earth metal or the metal compound containing the alkali metal in the nonvolatile component is 0.5 mass% or more and less than 100 mass%, according to any one of claims 1 to 10. A barrier layer forming composition.
  12. 　２５℃における粘度が０．５Ｐａ・ｓ以上４００Ｐａ・ｓ以下である請求項１～請求項１１のいずれか１項に記載のバリア層形成用組成物。 The composition for forming a barrier layer according to any one of claims 1 to 11, having a viscosity at 25 ° C of 0.5 Pa · s to 400 Pa · s.
  13. 　不揮発成分中の、前記アルカリ土類金属又はアルカリ金属を含有する金属化合物の含有率が、１０質量％以上５５質量％以下である、請求項１～請求項１２に記載のバリア層形成用組成物。 The composition for forming a barrier layer according to any one of claims 1 to 12, wherein a content of the alkaline earth metal or the metal compound containing the alkali metal in the nonvolatile component is 10% by mass or more and 55% by mass or less. .
  14. 　２５℃における粘度が４０Ｐａ・ｓ以上２００Ｐａ・ｓ以下である請求項１～請求項１３のいずれか１項に記載のバリア層形成用組成物。 The barrier layer forming composition according to any one of claims 1 to 13, which has a viscosity at 25 ° C of 40 Pa · s to 200 Pa · s.
  15. 　前記アルカリ土類金属又はアルカリ金属を含有する金属化合物が、酸化カルシウム及び炭酸カルシウムからなる群より選択される１種以上を含む、請求項１～請求項１４のいずれか１項に記載のバリア層形成用組成物。 The barrier layer according to any one of claims 1 to 14, wherein the alkaline earth metal or the metal compound containing an alkali metal includes one or more selected from the group consisting of calcium oxide and calcium carbonate. Forming composition.
  16. 　更に、チキソ剤を含有する、請求項１～請求項１５のいずれか１項に記載のバリア層形成用組成物。 The barrier layer-forming composition according to any one of claims 1 to 15, further comprising a thixotropic agent.
  17. 　半導体基板に部分的に拡散層を形成するためのバリア層の形成に用いられる、請求項１～請求項１６のいずれか１項に記載のバリア層形成用組成物。 The composition for forming a barrier layer according to any one of claims 1 to 16, which is used for forming a barrier layer for partially forming a diffusion layer on a semiconductor substrate.
  18. 　請求項１～請求項１７のいずれか１項に記載のバリア層形成用組成物の乾燥体であるバリア層。 A barrier layer, which is a dried body of the composition for forming a barrier layer according to any one of claims 1 to 17.
  19. 　請求項１～請求項１７のいずれか１項に記載のバリア層形成用組成物を半導体基板上に付与してパターン状のバリア層を形成する工程と、
    　前記半導体基板上の前記バリア層が形成されていない部分に、ドナー元素又はアクセプター元素を拡散して、前記半導体基板内に部分的に拡散層を形成する工程と、
    　を含む、太陽電池用基板の製造方法。     Applying the barrier layer forming composition according to any one of claims 1 to 17 on a semiconductor substrate to form a patterned barrier layer;
    A step of diffusing a donor element or an acceptor element in a portion where the barrier layer is not formed on the semiconductor substrate, and forming a diffusion layer partially in the semiconductor substrate;
    The manufacturing method of the board | substrate for solar cells containing.
  20. 　前記バリア層形成用組成物を付与する方法が、印刷法又はインクジェット法である、請求項１９に記載の太陽電池用基板の製造方法。 The method for producing a substrate for a solar cell according to claim 19, wherein the method for applying the composition for forming a barrier layer is a printing method or an inkjet method.
  21. 　請求項１９又は請求項２０に記載の製造方法により得られる太陽電池用基板の拡散層上に、電極を形成する工程を含む、太陽電池素子の製造方法。 A method for manufacturing a solar cell element, comprising a step of forming an electrode on a diffusion layer of a solar cell substrate obtained by the manufacturing method according to claim 19 or 20.
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