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WO2018003141A1 - Composition de formation de couche de passivation, substrat semi-conducteur à couche de passivation, procédé de fabrication de substrat semi-conducteur à couche de passivation, élément de cellule solaire, procédé de fabrication d'élément de cellule solaire, et cellule solaire - Google Patents

Composition de formation de couche de passivation, substrat semi-conducteur à couche de passivation, procédé de fabrication de substrat semi-conducteur à couche de passivation, élément de cellule solaire, procédé de fabrication d'élément de cellule solaire, et cellule solaire Download PDF

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WO2018003141A1
WO2018003141A1 PCT/JP2016/086248 JP2016086248W WO2018003141A1 WO 2018003141 A1 WO2018003141 A1 WO 2018003141A1 JP 2016086248 W JP2016086248 W JP 2016086248W WO 2018003141 A1 WO2018003141 A1 WO 2018003141A1
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passivation layer
composition
forming
semiconductor substrate
layer
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Japanese (ja)
Inventor
麻理 清水
野尻　剛
田中　直敬
光祥 濱田
真年 森下
剛 早坂
児玉　俊輔
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Resonac Corp
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Hitachi Chemical Co Ltd
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/30—Coatings
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a composition for forming a passivation layer, a semiconductor substrate with a passivation layer, a method for manufacturing a semiconductor substrate with a passivation layer, a solar cell element, a method for manufacturing a solar cell element, and a solar cell.
  • a p-type silicon substrate having a textured structure is prepared so as to promote the light confinement effect and increase the efficiency.
  • a mixed gas atmosphere of phosphorus oxychloride (POCl 3 ), nitrogen and oxygen is used at 800 ° C. to 900 ° Several tens of minutes are performed at a temperature to uniformly form the n-type diffusion layer on the surface of the p-type silicon substrate.
  • n-type diffusion layers are formed not only on the light-receiving surface of the p-type silicon substrate but also on the side surface and the back surface. Therefore, side etching is performed to remove the n-type diffusion layer formed on the side surface. Further, the n-type diffusion layer formed on the back surface needs to be converted into a p + -type diffusion layer. For this reason, an aluminum paste containing aluminum powder, a binder, etc. is applied to the whole or a part of the back surface, and this is heat-treated (fired) to form an aluminum electrode, and an n-type diffusion layer is formed as a p + -type diffusion. Ohmic contact is obtained by converting into layers.
  • the aluminum electrode formed from the aluminum paste has low conductivity. Therefore, in order to reduce the sheet resistance of the aluminum electrode, the aluminum electrode generally formed on the entire back surface must have a thickness of about 10 ⁇ m to 20 ⁇ m after heat treatment (firing). Furthermore, since the thermal expansion coefficient differs greatly between silicon and aluminum, a large internal stress is generated in the silicon substrate during the heat treatment (firing) and cooling for forming the aluminum electrode on the silicon substrate. This large internal stress causes crystal grain boundary damage, crystal defect growth and warpage.
  • an aluminum paste is applied to a part of the surface opposite to the light receiving surface of the silicon substrate (hereinafter also referred to as “back surface”) to partially form a p + -type diffusion layer and an aluminum electrode.
  • a point contact technique has been proposed (see, for example, Patent Document 1).
  • a SiO 2 film or the like as a back surface passivation layer (see, for example, Patent Document 2).
  • the passivation effect by providing such a SiO 2 film is exhibited by the action of terminating the dangling bonds of silicon atoms in the back surface layer portion of the silicon substrate and reducing the surface state density that causes recombination.
  • Such a passivation effect is generally called a field effect, and an aluminum oxide (Al 2 O 3 ) film or the like has been proposed as a material having a negative fixed charge (see, for example, Patent Document 3).
  • Such a passivation layer is generally formed by a method such as an ALD (Atomic Layer Deposition) method or a CVD (Chemical Vapor Deposition) method (for example, see Non-Patent Document 1).
  • Non-Patent Document 1 since the method described in Non-Patent Document 1 includes a complicated manufacturing process such as vapor deposition, it may be difficult to improve productivity.
  • the present inventors have studied a passivation layer forming composition containing an aluminum oxide precursor as a simple technique for forming an aluminum oxide layer on a semiconductor substrate.
  • the passivation layer can be formed on the semiconductor substrate by a simple method such as printing.
  • voids may be generated in the formed passivation layer, or a heterogeneous passivation layer may be formed, which may reduce the lifetime of the semiconductor substrate. .
  • the present invention has been made in view of the above problems, and provides a composition for forming a passivation layer capable of forming a passivation layer having excellent denseness and a sufficient passivation effect by a simple technique. Let it be an issue. Moreover, this invention makes it a subject to provide the semiconductor substrate with a passivation layer which has sufficient passivation effect, a solar cell element, and a solar cell. Furthermore, this invention makes it a subject to provide the manufacturing method of the semiconductor substrate with a passivation layer which can form the passivation layer which has sufficient passivation effect by a simple method, and the manufacturing method of a solar cell element.
  • a composition for forming a passivation layer comprising an aluminum oxide precursor and a silicon compound.
  • each R 1 independently represents an alkyl group.
  • n represents an integer of 0 to 3.
  • X 2 and X 3 each independently represent an oxygen atom or a methylene group.
  • R 2 , R 3 and R 4 each independently represent a hydrogen atom or an alkyl group.
  • composition for forming a passivation layer according to ⁇ 1> or ⁇ 2> wherein the content of the silicon compound is 0.01% by mass to 35% by mass in the composition for forming a passivation layer.
  • ⁇ 4> The composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 3>, wherein the silicon atom content is 0.001% by mass to 15% by mass in the composition for forming a passivation layer. .
  • composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 4>, wherein the silicon compound includes at least one selected from the group consisting of a silicate compound, silicon alkoxide, and silicone oil.
  • composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 5>, wherein the silicon compound includes a silicate compound, and the silicate compound includes a compound represented by the following general formula (II): . Si n O n-1 (RO) 2 (n + 1) (II)
  • R represents an alkyl group having 1 to 8 carbon atoms.
  • n represents an integer of 1 to 10.
  • composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 6>, wherein the silicon compound includes a silicon alkoxide, and the silicon alkoxide includes a silane coupling agent.
  • a passivation layer which is a heat treatment product of the composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 9>, provided on at least a part of at least one surface of the semiconductor substrate;
  • a semiconductor substrate with a passivation layer is a heat treatment product of the composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 9>, provided on at least a part of at least one surface of the semiconductor substrate.
  • ⁇ 12> a semiconductor substrate having a pn junction part in which a p-type layer and an n-type layer are pn-junction;
  • a solar cell element having
  • the passivation layer according to any one of ⁇ 1> to ⁇ 9>, provided on at least a part of at least one surface of a semiconductor substrate having a pn junction formed by joining a p-type layer and an n-type layer.
  • the solar cell element according to ⁇ 12> which includes a semiconductor substrate, a heat-treated product layer, and an electrode; A wiring material disposed on the electrode; A solar cell having:
  • this invention it is possible to provide a composition for forming a passivation layer capable of forming a passivation layer having excellent denseness and a sufficient passivation effect by a simple technique. Moreover, this invention can provide the semiconductor substrate with a passivation layer which has sufficient passivation effect, a solar cell element, and a solar cell. Furthermore, this invention can provide the manufacturing method of the semiconductor substrate with a passivation layer which can form the passivation layer which has sufficient passivation effect by a simple method, and the manufacturing method of a solar cell element.
  • a numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
  • the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range.
  • the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
  • the content rate or content of each component in the composition is such that when there are a plurality of substances corresponding to each component in the composition, the plurality of kinds present in the composition unless otherwise specified. It means the total content or content of substances.
  • the term “layer” includes a configuration formed in a part in addition to a configuration formed in the entire surface when observed as a plan view. Further, in this specification, “layer” may be referred to as “film”.
  • composition for forming a passivation layer of this embodiment contains an aluminum oxide precursor and a silicon compound.
  • the composition for forming a passivation layer may further contain other components as necessary.
  • a passivation layer-forming composition containing an aluminum oxide precursor and a silicon compound is applied to a semiconductor substrate to form a composition layer, which is then heat-treated (fired) to provide a passivation layer having an excellent passivation effect.
  • the composition for forming a passivation layer contains a silicon compound
  • the surface tension is controlled, thickness unevenness of the composition layer that is a coating film is suppressed, and variations in the thickness of the formed passivation layer are suppressed.
  • surface tension is controlled, generation
  • the denseness of the passivation layer can be evaluated by visually confirming the occurrence of unevenness and voids from the contrast of the observed image using a transmission electron microscope.
  • the passivation layer forming composition When the passivation layer forming composition is heat-treated (fired), Al 2 O 3 is generated from the aluminum oxide precursor. At this time, Al 2 O 3 starts to be generated from a plurality of starting points, gradually increases to form a phase, and adjacent phases have different crystallinity, generation direction, and the like, so that an interface is formed. For this reason, the interface also occurs between the Al 2 O 3 phase and the Al 2 O 3 phase. For example, when Nb is included in addition to Al, it occurs between the Nb 2 O 5 phase and the AlNbO 4 phase. Can be considered. In some cases, the phase in the passivation layer can be observed from an image of a transmission electron microscope.
  • the passivation layer obtained by heat-treating (firing) the composition for forming a passivation layer may have a plurality of phases and an interface between phases. At this interface, it is assumed that the entry speed of a substance (such as a hydrogen atom) that inhibits the passivation effect existing outside is faster than that in the phase. This phenomenon occurs because the diffusion rate of the substance depends on the density in the moving medium. Since the inside of the phase is filled with the substance, the entry speed of hydrogen atoms from the outside is slow. On the other hand, it can be said that hydrogen atoms and the like easily enter because there are voids, defects, and the like in atomic size as the material changes at the phase interface. For this reason, hydrogen atoms and the like existing outside may be diffused by reaching the substrate through the interface, and as a result, the passivation effect may be reduced.
  • a substance such as a hydrogen atom
  • silicon compound when contained in the composition for forming a passivation layer, it is presumed that when heat treatment (firing), silicon atoms move to the interface and are unevenly distributed there. This is considered to be due to the fact that the atomic radius of silicon atoms is a size that is easy to move in the phase by heat treatment (firing) and that it is suitable for existing at the interface.
  • the silicon atoms present at the interface are considered to fill the voids, defects and the like at the interface, and the entrance rate of hydrogen atoms and the like from the outside is reduced, and it is assumed that a sufficient passivation effect is obtained as a result.
  • the passivation effect of a semiconductor substrate is obtained by reflecting the effective lifetime of minority carriers in a semiconductor substrate on which a passivation layer is formed using a reflection microwave conduction device using a device such as WT-2000PVN (Nihon Semi-Lab Co., Ltd.). It can be evaluated by measuring by the attenuation method.
  • the effective lifetime ⁇ is expressed by the following equation (A) by the bulk lifetime ⁇ b inside the semiconductor substrate and the surface lifetime ⁇ s of the semiconductor substrate surface.
  • ⁇ s becomes long, resulting in a long effective lifetime ⁇ .
  • the bulk lifetime ⁇ b is increased and the effective lifetime ⁇ is increased. That is, by measuring the effective lifetime ⁇ , the interface characteristics between the passivation layer and the semiconductor substrate and the internal characteristics of the semiconductor substrate such as dangling bonds can be evaluated.
  • the composition for forming a passivation layer contains an aluminum oxide precursor.
  • the aluminum compound is not particularly limited as long as it generates aluminum oxide by heat treatment (firing).
  • An aluminum oxide precursor may be used individually by 1 type, or may use 2 or more types together.
  • the aluminum oxide precursor becomes aluminum oxide (Al 2 O 3 ) by heat treatment (firing). At this time, the formed aluminum oxide tends to be in an amorphous state, and a four-coordinate aluminum oxide layer is easily formed in the vicinity of the interface with the semiconductor substrate. It is considered that due to the four-coordinate aluminum oxide layer, a large negative fixed charge can be provided in the vicinity of the interface with the semiconductor substrate. Thereby, an electric field is generated in the vicinity of the interface with the semiconductor substrate, and the concentration of minority carriers can be reduced. As a result, it is considered that the carrier recombination rate at the interface with the semiconductor substrate is suppressed, and an excellent passivation effect is obtained.
  • Tetracoordinated aluminum oxide is considered to be a structure in which the center of silicon dioxide (SiO 2 ) is isomorphously substituted from silicon to aluminum, and is formed as a negative charge source at the interface between silicon dioxide and aluminum oxide like zeolite and clay. It is known.
  • the state of the formed aluminum oxide can be confirmed by measuring an X-ray diffraction spectrum (XRD, X-ray diffraction). For example, it can be confirmed that the XRD has an amorphous structure by not showing a specific reflection pattern.
  • the negative fixed charge which aluminum oxide has can be evaluated by CV method (Capacitance Voltage measurement).
  • the passivation layer formed from the passivation layer forming composition of the present embodiment has a surface state density obtained by the CV method that is larger than that of an aluminum oxide layer formed by the ALD method or the CVD method. It may become.
  • the passivation layer formed from the composition for forming a passivation layer according to this embodiment has a large electric field effect, the minority carrier concentration decreases and the surface lifetime ⁇ s increases. Therefore, the surface state density is not a relative problem.
  • the aluminum oxide precursor may be liquid or solid. From the viewpoint of the passivation effect and storage stability, when using a liquid medium with stability at normal temperature (for example, 25 ° C.), use an aluminum oxide precursor having good solubility or dispersibility in the liquid medium. Is desirable. By using such an aluminum oxide precursor, the homogeneity of the formed passivation layer is further improved, and a desired passivation effect tends to be stably obtained.
  • an organic aluminum oxide precursor is preferably used, and examples thereof include compounds represented by the following general formula (I) (hereinafter also referred to as “specific aluminum compounds”).
  • the composition for forming a passivation layer may contain a hydrolyzate of a specific aluminum compound.
  • each R 1 independently represents an alkyl group.
  • n represents an integer of 0 to 3.
  • X 2 and X 3 each independently represent an oxygen atom or a methylene group.
  • R 2 , R 3 and R 4 each independently represent a hydrogen atom or an alkyl group.
  • a plurality of groups represented by the same symbol may be the same or different.
  • each R 1 independently represents an alkyl group, preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.
  • the alkyl group represented by R 1 may be linear or branched.
  • the alkyl group represented by R 1 may have a substituent or may be unsubstituted, and is preferably unsubstituted. Examples of the substituent for the alkyl group include an amino group, a hydroxy group, a carboxy group, a sulfo group, and a nitro group. Note that the carbon number of the alkyl group represented by R 1 does not include the carbon number of the substituent.
  • the alkyl group represented by R 1 is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms from the viewpoint of storage stability and a passivation effect, and is an unsubstituted alkyl group having 1 to 4 carbon atoms. It is more preferable.
  • alkyl group represented by R 1 examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, and an n-hexyl group. N-octyl group, 2-ethylhexyl group, 3-ethylhexyl group and the like.
  • n represents an integer of 0 to 3. From the viewpoint of suppressing the occurrence of defects such as gelation and ensuring storage stability over time, n is preferably an integer of 1 to 3, more preferably 1 or 3, and from the viewpoint of solubility. Is more preferably 1.
  • X 2 and X 3 each independently represent an oxygen atom or a methylene group. From the viewpoint of storage stability, at least one of X 2 and X 3 is preferably an oxygen atom.
  • R 2 , R 3 and R 4 in the general formula (I) each independently represent a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, It is more preferably 1 to 4 alkyl groups.
  • the alkyl group represented by R 2 , R 3 and R 4 may be linear or branched.
  • the alkyl group represented by R 2 , R 3 and R 4 may have a substituent or may be unsubstituted, and is preferably unsubstituted. Examples of the substituent for the alkyl group include an amino group, a hydroxy group, a carboxy group, a sulfo group, and a nitro group. Note that the carbon number of the alkyl group represented by R 2 , R 3, and R 4 does not include the carbon number of the substituent.
  • R 2 and R 3 in formula (I) are preferably each independently a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms. Or it is more preferably an unsubstituted alkyl group having 1 to 4 carbon atoms.
  • R 4 in the general formula (I) is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms from the viewpoint of storage stability and a passivation effect, and is preferably a hydrogen atom or a carbon atom having 1 to 4 carbon atoms. It is more preferably an unsubstituted alkyl group.
  • alkyl group represented by R 2 , R 3 and R 4 in the general formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a sec-butyl group.
  • the specific aluminum compound is a compound in which n in the general formula (I) is 0 and R 1 is each independently an alkyl group having 1 to 4 carbon atoms from the viewpoint of storage stability and a passivation effect, N in the formula (I) is an integer of 1 to 3, R 1 is independently an alkyl group having 1 to 4 carbon atoms, and at least one of X 2 and X 3 is an oxygen atom, R 2 and R 3 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 4 is each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. It is preferable that at least one selected.
  • the specific aluminum compound is a compound in which n in the general formula (I) is 0, and each R 1 is independently an unsubstituted alkyl group having 1 to 4 carbon atoms, and the general formula (I ) Is an integer of 1 to 3, R 1 is each independently an unsubstituted alkyl group having 1 to 4 carbon atoms, and at least one of X 2 and X 3 is an oxygen atom, When R 2 or R 3 bonded to the oxygen atom is an alkyl group having 1 to 4 carbon atoms and X 2 or X 3 is a methylene group, R 2 or R 3 bonded to the methylene group is a hydrogen atom. In addition, it is preferable that at least one selected from the group consisting of compounds in which R 4 is a hydrogen atom.
  • the specific aluminum compound has a general formula (I) in which n is 1 to 3, and R 4 is independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A certain compound is preferable.
  • Specific examples of the specific aluminum compound (aluminum trialkoxide) in which n is 0 in the general formula (I) include trimethoxyaluminum, triethoxyaluminum, triisopropoxyaluminum, trisec-butoxyaluminum, monosec-butoxy- Examples thereof include diisopropoxyaluminum, tri-t-butoxyaluminum, and tri-n-butoxyaluminum.
  • n is an integer of 1 to 3
  • specific aluminum compound in the general formula (I) where n is an integer of 1 to 3 include aluminum ethyl acetoacetate diisopropylate, aluminum methyl acetoacetate diisopropylate, aluminum tris (ethyl acetoacetate), aluminum Examples thereof include monoacetylacetonate bis (ethylacetoacetate) and aluminum tris (acetylacetonate).
  • the specific aluminum compound in which n is an integer of 1 to 3 may be prepared or commercially available.
  • Commercially available products include, for example, trade names of Kawaken Fine Chemical Co., Ltd., ALCH, ALCH-50F, ALCH-75, ALCH-TR, ALCH-TR-20, aluminum chelate M, aluminum chelate D, and aluminum chelate A (W ).
  • the specific aluminum compound in which n is an integer of 1 to 3 can be prepared by mixing an aluminum trialkoxide and a compound having a specific structure having two carbonyl groups.
  • an aluminum trialkoxide and a compound having a specific structure having two carbonyl groups are mixed, at least a part of the alkoxy group of the aluminum trialkoxide is substituted with a compound having a specific structure to form an aluminum chelate structure.
  • a liquid medium may be present, and heat treatment, addition of a catalyst, and the like may be performed.
  • the stability of the specific aluminum compound to hydrolysis and polymerization reaction is improved, and the storage stability of the composition for forming a passivation layer containing this is further improved. To do. Further, the closer the reactivity to a silicon compound described later, the easier it is to form a dense passivation layer.
  • the compound having a specific structure having two carbonyl groups is at least one selected from the group consisting of ⁇ -diketone compounds, ⁇ -ketoester compounds, and malonic acid diesters from the viewpoints of reactivity and storage stability. Is preferred.
  • Specific compounds having two carbonyl groups include, for example, acetylacetone, 3-methyl-2,4-pentanedione, 2,3-pentanedione, 3-ethyl-2,4-pentanedione, 3-butyl-2 , 4-pentanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 2,6-dimethyl-3,5-heptanedione, 6-methyl-2,4-heptanedione, etc.
  • Diketone compounds methyl acetoacetate, ethyl acetoacetate, n-propyl acetoacetate, isopropyl acetoacetate, isobutyl acetoacetate, n-butyl acetoacetate, t-butyl acetoacetate, n-pentyl acetoacetate, isopentyl acetoacetate, acetoacetic acid n-hexyl, n-octyl acetoacetate, n-heptyl acetoacetate, 3-pentyl acetoacetate, 2-acetyl Ethyl heptanoate, ethyl 2-methylacetoacetate, ethyl 2-butylacetoacetate, ethyl hexylacetoacetate, ethyl 4,4-dimethyl-3-oxovalerate, ethyl 4-methyl-3-oxovalerate, ethyl 2-eth
  • the number of aluminum chelate structures is not particularly limited as long as it is 1 to 3. Among these, 1 or 3 is preferable from the viewpoint of storage stability, and 1 is more preferable from the viewpoint of solubility.
  • the number of aluminum chelate structures can be controlled, for example, by appropriately adjusting the ratio of mixing aluminum trialkoxide and a compound capable of forming a chelate with aluminum. Moreover, you may select suitably the compound which has a desired structure from a commercially available aluminum chelate compound.
  • the presence of the aluminum chelate structure and the presence of the alkoxide structure in the specific aluminum compound can be confirmed by a commonly used analysis method. Specifically, it can be confirmed using an infrared spectrum, a nuclear magnetic resonance spectrum, a melting point and the like.
  • the specific aluminum compound represented by the general formula (I) is selected from the group consisting of aluminum ethyl acetoacetate diisopropylate and triisopropoxyaluminum from the viewpoint of the passivation effect and compatibility with the solvent contained as necessary. It is preferable to contain at least one selected from the group consisting of aluminum ethyl acetoacetate diisopropylate.
  • the content of the specific aluminum compound in the aluminum oxide precursor is, for example, preferably 80% by mass or more, more preferably 90% by mass or more, and 95 More preferably, it is at least mass%.
  • the content of the aluminum oxide precursor contained in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the content of the aluminum oxide precursor is preferably, for example, 0.1% by mass to 60% by mass with respect to the total mass of the composition for forming a passivation layer.
  • the content is more preferably 0.5% by mass to 55% by mass, further preferably 1% by mass to 50% by mass, and particularly preferably 1% by mass to 45% by mass.
  • the composition for forming a passivation layer contains a silicon compound.
  • the silicon compound is passivated by a physical or chemical interaction or chemical bond with a specific aluminum compound in the composition for forming a passivation layer (and, if necessary, a resin, a liquid medium, etc.).
  • the surface tension of the layer forming composition can be controlled. Thereby, the thickness nonuniformity of a composition layer is suppressed and the variation in the thickness of the passivation layer formed is suppressed.
  • generation of voids in the heat-treated product layer (baked product layer) of the composition for forming a passivation layer is suppressed, the denseness of the passivation layer is improved, and a uniform passivation layer is formed. Is obtained.
  • a silicon compound will not be specifically limited if the silicon atom is contained in the molecule
  • the silicon compound is preferably a compound in which an oxygen atom is bonded to a silicon atom from the viewpoint of easy preparation of the composition for forming a passivation layer.
  • the compound in which an oxygen atom is bonded to a silicon atom may form a complex with at least one selected from the group consisting of an organic compound and an inorganic compound.
  • Specific examples of the silicon compound include silicon alkoxides, silicate compounds, and silicone oils and siloxane resins that are compounds having a siloxane bond. Among these, silicon alkoxides, silicate compounds, and silicone oils are preferable.
  • the silicone oil may be a copolymer of a compound having a siloxane bond and another compound.
  • the silicon alkoxide and silicate compound may be oligomers.
  • silicate compound oligomer examples include compounds represented by the following general formula (II). Si n O n-1 (RO) 2 (n + 1) (II)
  • R represents an alkyl group having 1 to 8 carbon atoms.
  • n represents an integer of 1 to 10.
  • the silicate compound include methyl silicate, ethyl silicate, isopropyl silicate, n-propyl silicate, n-butyl silicate, n-pentyl silicate, and acetyl silicate.
  • methyl silicate and its oligomer include methyl silicate 51 manufactured by Fuso Chemical Industry Co., Ltd. or Colcoat Co., Ltd., methyl silicate 53A manufactured by Colcoat Co., Ltd., and the like.
  • ethyl silicate and oligomers thereof include ethyl silicate 40 of Tama Chemical Co., Ltd.
  • the silicon compound preferably contains a compound represented by the general formula (II).
  • the compound represented by the general formula (II) has a slow reaction with the aluminum oxide precursor in the heat treatment (firing), and the reaction can be suppressed to a specific temperature state.
  • the reaction occurs uniformly, the generation of voids in the heat-treated product layer (baked product layer) is suppressed, and the denseness of the passivation layer is improved.
  • the silicate compound is preferably an ethyl silicate compound or an oligomer of ethyl silicate.
  • the plurality of RO groups possessed by the silicate compound may be the same or different.
  • the RO group preferably includes both a methoxy group and an ethoxy group.
  • the ratio of the equivalent number of methoxy groups to the equivalent number of ethoxy groups is preferably, for example, 30/70 to 70/30 40/60 to 60/40, more preferably 45/55 to 55/45, and the number of equivalents of methoxy group and the number of equivalents of ethoxy group are particularly preferably close to equivalent.
  • An example of a silicate compound having approximately equal amounts of methoxy group and ethoxy group is EMS-485 manufactured by Colcoat Co., Ltd.
  • the silicate compound may be used alone or in combination of two or more.
  • the silicate compound may be used in combination with water, a catalyst, a liquid medium, or the like, if necessary.
  • the silicon alkoxide is not particularly limited as long as it has a silicon atom and an alkoxy group bonded to the silicon atom.
  • Specific examples of the silicon alkoxide include compounds represented by the following general formula (III). R n Si (OR 1 ) 4-n (III)
  • R represents an alkyl group or an aryl group, the alkyl group and the aryl group may have a substituent, and R 1 represents a saturated or unsaturated carbon atom having 1 to 6 carbon atoms.
  • R 1 represents a saturated or unsaturated carbon atom having 1 to 6 carbon atoms.
  • a hydrogen group or a hydrocarbon group having 1 to 6 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms is shown.
  • n represents 1 to 3, and preferably 1 or 2.
  • the alkyl group represented by R in the general formula (III) preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, and still more preferably 1 to 3 carbon atoms.
  • the aryl group represented by R in the general formula (III) preferably has 6 to 14 carbon atoms, and more preferably a phenyl group.
  • examples of the substituent that the alkyl group represented by R may have include a fluorine atom, a (meth) acryloxy group, a vinyl group, an epoxy group, a styryl group, and an amino group.
  • the amino group may further have a substituent, and examples of the amino group having a substituent include an N-2- (aminoethyl) -3-amino group and an N-phenyl-3-amino group.
  • Examples of the saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms represented by R 1 in the general formula (III) include methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, cyclohexyl Etc.
  • Examples of the hydrocarbon group having 1 to 6 carbon atoms substituted by an alkoxy group having 1 to 6 carbon atoms represented by R 1 in the general formula (III) include methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl , Methoxypropyl, ethoxypropyl, propoxypropyl and the like.
  • the silicon alkoxide preferably contains a silane coupling agent.
  • the silane coupling agent is not particularly limited as long as it is a compound having a silicon atom, an alkoxy group, and an organic functional group other than the alkoxy group in one molecule.
  • a silane coupling agent may be used individually by 1 type, and may use 2 or more types together.
  • Examples of the silicon alkoxide include the following compounds (a) to (g) containing a silane coupling agent.
  • Silicon alkoxide having (meth) acryloxy group (b) Epoxy group such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane Or a silicon alkoxide having a glycidoxy group (c) N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-amino Silicon alkoxide having amino group such as propyltriethoxysilane (d) Silicon alkoxide having mercapto group such as 3-mercaptopropyltrimethoxysilane (e) Methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldi
  • Silicon alkoxide having an alkyl group Silicon alkoxide having a phenyl group such as phenyltrimethoxysilane, phenyltriethoxysilane, etc.
  • phenyl group such as phenyltrimethoxysilane, phenyltriethoxysilane, etc.
  • g Trifluoropropyltrimethoxy Silicon alkoxide having a trifluoroalkyl group run like
  • the silicon alkoxide preferably includes a silicon alkoxide having an acryloxy group, a methacryloxy group, an epoxy group, an alkyl group, or a trifluoroalkyl group. Silicon alkoxide may be used in combination with water, a catalyst, a liquid medium, or the like, if necessary.
  • Silicone oil is not particularly limited. Specific examples of the silicone oil include dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, fluorine-modified silicone oil, amino-modified silicone oil, and mercapto. Modified silicone oil, epoxy modified silicone oil, carboxyl modified silicone oil, higher fatty acid modified silicone oil, carnauba modified silicone oil, amide modified silicone oil, radical reactive group containing silicone oil, terminal reactive silicone oil, ionic group containing silicone oil Etc.
  • the content of the silicon compound is, for example, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, with respect to the total mass of the composition for forming a passivation layer, More preferably, it is at least mass%.
  • the content of the silicon compound is 0.01% by mass or more, the surface tension of the passivation layer forming composition is lowered, and the coatability and printability tend to be improved.
  • the content of the silicon compound is, for example, preferably 35% by mass or less, more preferably 30% by mass or less, and 20% by mass or less with respect to the total mass of the composition for forming a passivation layer. More preferably, it is particularly preferably 10% by mass or less, and from the viewpoint of applicability, it is extremely preferably 8% by mass or less. It exists in the tendency for the passivation effect to be more fully acquired as the content rate of a silicon compound is 35 mass% or less.
  • the silicon atom content in the composition for forming a passivation layer is preferably 0.001% by mass to 15% by mass, more preferably 0.01% by mass to 10% by mass, and 0.05% by mass. More preferably, the content is from 5% to 5% by mass.
  • the composition for forming a passivation layer may further contain another metal compound containing a metal element other than aluminum.
  • the metal compound include metal alkoxides containing metal elements other than aluminum, metal complexes such as chelate complexes, and organometallic compounds.
  • Another metal compound may be used individually by 1 type, and may use 2 or more types together.
  • the composition for forming a passivation film contains other metal compounds, a larger negative fixed charge is developed, and the passivation effect tends to be further improved.
  • a passivation layer forming composition containing another metal compound is heat-treated (fired)
  • a composite oxide having a large refractive index may be generated by aluminum and the other metal.
  • the passivation layer containing a complex oxide with a high refractive index improves the power generation performance because sunlight is refracted at the interface with the semiconductor substrate and re-enters the solar cells while preventing the sunlight from escaping to the back side. Tend to.
  • the other metal compound preferably contains a metal alkoxide from the viewpoint of reactivity with the aluminum oxide precursor and the silicon compound.
  • the metal alkoxide is not particularly limited as long as it is a compound obtained by reacting a metal atom with an alcohol.
  • Specific examples of the metal alkoxide include a compound represented by the following general formula (1) (hereinafter also referred to as “compound (1)”) and a compound represented by the following general formula (2) (hereinafter referred to as “formula ( 2) Compound ”).
  • M 1 represents at least one selected from the group consisting of Nb, Ta, VO, Y, and Hf.
  • R 5 each independently represents an alkyl group, an aryl group or an acyl group.
  • p represents the valence of M 1.
  • M 2 represents a metal element having a valence of 1 to 7 (excluding Al, Nb, Ta, VO, Y, and Hf).
  • R 6 represents a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms, or a hydrocarbon group having 1 to 6 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms.
  • t represents the valence of M 2.
  • M 1 is at least one selected from the group consisting of Nb, Ta, VO, Y, and Hf, and includes a passivation effect, a pattern forming property of the composition for forming a passivation layer, and a passivation. From the viewpoint of workability when preparing the layer forming composition, M 1 is preferably at least one selected from the group consisting of Nb, Ta, and Y. From the viewpoint of the passivation effect, Nb is more preferable.
  • each R 5 independently represents an alkyl group, an aryl group, or an acyl group, and is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms, or 1 to 10 carbon atoms.
  • the acyl group is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms.
  • the alkyl group represented by R 5 may be linear or branched.
  • the alkyl group and aryl group represented by R 5 may have a substituent or may be unsubstituted, and is preferably unsubstituted.
  • substituent for the alkyl group include an amino group, a hydroxy group, a carboxy group, a sulfo group, and a nitro group.
  • substituent for the aryl group include a methyl group, an ethyl group, an isopropyl group, an amino group, a hydroxy group, a carboxy group, a sulfo group, and a nitro group.
  • the acyl group represented by R 5 includes a carbonyl group moiety and a hydrogen atom directly bonded to a carbon atom of the alkyl group moiety, aryl group moiety or carbonyl group moiety.
  • the alkyl group moiety in the acyl group represented by R 5 may be linear or branched.
  • the alkyl group part and aryl group part in the acyl group represented by R 5 may have a substituent or may be unsubstituted, and is preferably unsubstituted.
  • Examples of the substituent of the alkyl group moiety in the acyl group represented by R 5 include a phenyl group, an amino group, a hydroxy group, a carboxy group, a sulfo group, and a nitro group, and an aryl group in the acyl group represented by R 5.
  • Examples of the substituent of the group part include a methyl group, an ethyl group, an isopropyl group, an amino group, a hydroxy group, a carboxy group, a sulfo group, and a nitro group. Note that the carbon number of the alkyl group and aryl group represented by R 5 does not include the carbon number of the substituent.
  • Examples of the alkyl group represented by R 5 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-hexyl group, Examples thereof include n-octyl group, 2-ethylhexyl group, and 3-ethylhexyl group.
  • Examples of the aryl group represented by R 5 include a phenyl group.
  • Specific examples of the acyl group represented by R 5 include a formyl group, an acetyl group, a benzoyl group, and a 2-ethylhexanoyl group.
  • R 5 is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, and more preferably an unsubstituted alkyl group having 1 to 4 carbon atoms.
  • p represents the valence of M 1 .
  • P is preferably 5 when M 1 is Nb, p is preferably 5 when M 1 is Ta, and p is 3 when M 1 is VO.
  • M 1 is Y, p is preferably 3, and when M 1 is Hf, p is preferably 4.
  • a compound in which M 1 is at least one selected from the group consisting of Nb, Ta, and Y, and R 5 is an unsubstituted alkyl group having 1 to 4 carbon atoms is preferable.
  • a compound in which M 1 is Nb and R 5 is an unsubstituted alkyl group having 1 to 4 carbon atoms is more preferable.
  • Examples of the compound of formula (1) in which R 5 is an alkyl group include niobium methoxide, niobium ethoxide, niobium isopropoxide, niobium n-propoxide, niobium n-butoxide, niobium t-butoxide, niobium isobutoxide, Tantalum methoxide, tantalum ethoxide, tantalum isopropoxide, tantalum n-propoxide, tantalum n-butoxide, tantalum t-butoxide, tantalum isobutoxide, yttrium methoxide, yttrium ethoxide, yttrium isopropoxide, yttrium n-propoxy Yttrium n-butoxide, yttrium t-butoxide, yttrium isobutoxide, vanadium oxymethoxide, vanadium oxy
  • R 5 is an aryl group
  • Specific examples of the compound of formula (1) in which R 5 is an aryl group include niobium phenoxide, tantalum phenoxide, yttrium phenoxide, hafnium phenoxide, and the like.
  • R 5 is an acyl group
  • niobium formate niobium acetate, niobium 2-ethylhexanoate, tantalum acetate, tantalum 2-ethylhexanoate, yttrium formate, yttrium acetate, yttrium 2-ethylhexanoate
  • hafnium formate hafnium acetate
  • hafnium 2-ethylhexanoate examples include hafnium formate, hafnium acetate, and hafnium 2-ethylhexanoate.
  • a prepared product or a commercially available product may be used.
  • commercially available products include pentamethoxyniobium, pentaethoxyniobium, penta-i-propoxyniobium, penta-n-propoxyniobium, penta-i-butoxyniobium and penta-n-butoxyniobium from High Purity Chemical Laboratory Co., Ltd.
  • Penta-sec-butoxy niobium pentamethoxy tantalum, pentaethoxy tantalum, penta-i-propoxy tantalum, penta-n-propoxy tantalum, penta-i-butoxy tantalum, penta-n-butoxy tantalum, penta-sec-butoxy tantalum Penta-t-butoxytantalum, vanadium (V) trimethoxide oxide, vanadium (V) triethoxide oxide, vanadium (V) tri-i-propoxide oxide, vanadium (V) tri-n-propoxide oxide, vanadium( ) Tri-i-butoxide oxide, vanadium (V) tri-n-butoxide oxide, vanadium (V) tri-sec-butoxide oxide, vanadium (V) tri-t-butoxide oxide, tri-i-propoxy yttrium, tri- n-butoxy yttrium, tetramethoxy
  • Hafnium-tert-butoxide, vanadium oxytriethoxide, vanadium oxytrinormal propoxide, vanadium oxytrinormal butoxide, vanadium oxy from Nichia Corporation Triisobutoxide include vanadium oxy-tri secondary butoxide and the like.
  • the compound of formula (1) is prepared by reacting a halide of a specific metal (M 1 ) with an alcohol in the presence of an inert organic solvent, and further adding ammonia or amines to extract the halogen (Known manufacturing methods such as JP-A-63-227593 and JP-A-3-291247) can be used.
  • a part of the compound of the formula (1) is contained in the composition for forming a passivation layer as a compound having a chelate structure formed by mixing with a compound having a specific structure having two carbonyl groups, like the specific aluminum compound. Also good.
  • the presence of the alkoxide structure in the compound of formula (1) can be confirmed by a commonly used analysis method. For example, it can be confirmed using an infrared spectrum, a nuclear magnetic resonance spectrum, a melting point, or the like.
  • the compound of formula (1) may be solid or liquid at normal temperature (25 ° C.) and is not particularly limited. From the viewpoint of storage stability of the composition for forming a passivation layer and miscibility with other components such as a specific aluminum compound, the compound of formula (1) is preferably liquid at normal temperature (25 ° C.).
  • the content of the compound of the formula (1) contained in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the content of the compound of formula (1) is preferably 0.1% by mass to 60% by mass with respect to the total mass of the composition for forming a passivation layer,
  • the content is more preferably 0.5% by mass to 50% by mass, further preferably 1% by mass to 40% by mass, and particularly preferably 1% by mass to 30% by mass.
  • M 2 represents a metal element having a valence of 1 to 7 (excluding Al, Nb, Ta, VO, Y, and Hf).
  • M 2 Li, Na, K , Mg, Ca, Sr, Ba, La, Ti, B, Zr, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Zn, Pb
  • at least one metal element selected from the group consisting of Bi is Li, Na, K, Mg, Ca, Sr, Ba, La, Ti, B, Zr, Mo, Co, Zn, Pb.
  • at least one metal element selected from the group consisting of Bi and more preferably at least one metal element selected from the group consisting of Ti, Zr and Bi.
  • R 6 represents a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms or a hydrocarbon group having 1 to 6 carbon atoms substituted with an alkoxy group having 1 to 6 carbon atoms.
  • t represents the valence of M 2.
  • Examples of the group represented by R 6 in the general formula (2) include the same groups as the group represented by R 1 in the general formula (III).
  • the content of the other metal compound can be appropriately selected as necessary.
  • the total content of other metal compounds is preferably, for example, 0.1% by mass to 60% by mass with respect to the total mass of the composition for forming a passivation layer.
  • the content is more preferably 0.1% by mass to 50% by mass, further preferably 0.5% by mass to 50% by mass, particularly preferably 0.5% by mass to 30% by mass.
  • a mass% to 20 mass% is very particularly preferred.
  • the composition for forming a passivation layer may further contain a resin.
  • the shape stability of the composition layer formed by applying the composition for forming a passivation layer on a semiconductor substrate is further improved, and the passivation layer is formed in a desired shape. It can be selectively formed at a desired position.
  • the type of resin is not particularly limited.
  • the resin is preferably a resin whose viscosity can be adjusted within a range in which a satisfactory pattern can be formed when the composition for forming a passivation layer is applied onto a semiconductor substrate.
  • Specific examples of the resin include polyvinyl alcohol, polyacrylamide, polyacrylamide derivatives, polyvinylamide, polyvinylamide derivatives, polyvinylpyrrolidone, polyethylene oxide, polyethylene oxide derivatives, polysulfonic acid, polyacrylamide alkylsulfonic acid, cellulose, and cellulose derivatives (carboxymethylcellulose).
  • Cellulose ethers such as hydroxyethyl cellulose and ethyl cellulose
  • gelatin gelatin derivatives, starch, starch derivatives, sodium alginate, sodium alginate derivatives, xanthan, xanthan derivatives, guar gum, guar gum derivatives, scleroglucan, scleroglucan derivatives, tragacanth, Tragacanth derivative, dextrin, dextrin derivative, (meta)
  • crylic acid resin (meth) acrylic acid ester resin (alkyl (meth) acrylate resin, dimethylaminoethyl (meth) acrylate resin, etc.), butadiene resin, styrene resin, siloxane resin, and copolymers thereof.
  • (meth) acryl means at least one of acryl and methacryl
  • (meth) acrylate means at least one of acrylate and methacrylate.
  • the molecular weight of these resins is not particularly limited, and it is preferable to adjust appropriately in view of the desired viscosity as the composition for forming a passivation layer.
  • the weight average molecular weight of the resin is preferably, for example, 1,000 to 10,000,000, more preferably 1,000 to 5,000,000, from the viewpoint of storage stability and pattern formation. .
  • the weight average molecular weight of resin is calculated
  • the content of the resin in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the resin content is preferably 0.1% by mass to 50% by mass with respect to the total mass of the passivation layer forming composition.
  • the resin content is more preferably 0.2% by mass to 25% by mass, and more preferably 0.5% by mass to 20% by mass. Is more preferable, and 0.5 to 15% by mass is particularly preferable.
  • the content ratio of the aluminum oxide precursor and the resin in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the content ratio of the resin to the aluminum oxide precursor is preferably 0.001 to 1000, for example, 0.01 to 100 More preferably, it is more preferably 0.1-1.
  • the content of the resin contained in the composition for forming a passivation layer is preferably 0.5% by mass or less, and 0.2% by mass or less. More preferably, it is more preferably 0.1% by mass or less, and it is particularly preferable that the resin is substantially not contained.
  • the composition for forming a passivation layer may use a high boiling point material together with the resin or as a material replacing the resin.
  • the high boiling point material is preferably a compound that is easily vaporized when heated and does not need to be degreased.
  • the high boiling point material has a high viscosity so that the shape can be maintained after the composition for forming a passivation layer is applied to the semiconductor substrate.
  • An example of a material that satisfies these conditions is isobornylcyclohexanol.
  • Isobornyl cyclohexanol is commercially available, for example, as “Telsolve MTPH” (Nippon Terpene Chemical Co., Ltd., trade name). Isobornyl cyclohexanol has a high boiling point of 308 ° C. to 318 ° C. When it is removed from the composition layer, it does not need to be degreased by heat treatment (firing) like a resin, but is vaporized by heating. Can be eliminated. For this reason, most of the solvent and isobornyl cyclohexanol contained in the composition for forming a passivation layer as necessary can be removed in the drying step after application on the semiconductor substrate.
  • the content of the high boiling point material is, for example, 0.5% by mass to 95% by mass with respect to the total mass of the composition for forming a passivation layer. It is preferably 1% by mass to 90% by mass, more preferably 2% by mass to 80% by mass, and particularly preferably 5% by mass to 80% by mass.
  • the composition for forming a passivation layer may further contain a liquid medium (solvent or dispersion medium).
  • a liquid medium means a medium in a liquid state at room temperature (25 ° C.), except for water.
  • the liquid medium is not particularly limited and can be appropriately selected.
  • the liquid medium is a liquid medium in which an aluminum oxide precursor and a silicon compound (further, the compound of formula (I), the compound of formula (2) and a resin which may be contained if necessary) can be dissolved to form a uniform solution.
  • some specific aluminum compounds easily cause a reaction such as hydrolysis and polymerization reaction to be solidified as they are. However, the reaction is suppressed by being present in the solvent, and the storage stability tends to be improved as compared with the case where the specific aluminum compound is not present in the liquid medium.
  • liquid medium 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 di-n-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 di
  • Phenol solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monophenyl ether Ter, 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 ether, Examples include glycol monoether solvents such as dipropylene glycol monoethyl ether and tripropylene glycol monomethyl ether; terpene solvents such as terpinene, terpineol, myrcene, allocymene, limonene, dipentene, pinene, carvone, oximene, and ferrandrene. These liquid media may be used individually by 1 type, and may use 2 or more
  • the liquid medium preferably contains at least one selected from the group consisting of terpene solvents, ester solvents, and alcohol solvents, and is selected from the group consisting of terpene solvents. More preferably, it contains at least one of the above.
  • the content of the liquid medium is determined in consideration of impartability, pattern formability, and storage stability.
  • the content of the liquid medium is 5% by mass to 98% by mass with respect to the total mass of the composition for forming a passivation layer, from the viewpoint of impartability of the composition for forming a passivation layer and pattern forming properties. It is preferably 10% by mass to 95% by mass.
  • the composition for forming a passivation layer may contain water.
  • an aluminum oxide precursor, a silicon compound, and a compound of formula (1) and a compound of formula (2) contained as necessary is an alkoxy compound (including an acyloxy compound), for forming a passivation layer
  • an alkoxy compound including an acyloxy compound
  • the hydrolyzate may contain a reaction product of an aluminum oxide precursor, a silicon compound, a compound of formula (1) and a compound of formula (2) that are contained as necessary.
  • the hydrolyzate is considered to form a network between metal compounds.
  • this network is easily broken when the composition for forming a passivation layer is flowing, and is re-formed when the composition becomes stationary again.
  • This network increases the viscosity when the composition for forming a passivation layer is stationary, and decreases the viscosity when the composition is flowing.
  • the viscosity ratio at the high shear rate and the low shear rate of the composition for forming a passivation layer, that is, the thixotropy is improved, and the thixotropy necessary for pattern formation is expressed.
  • a composition layer formed by applying a composition for forming a passivation layer with improved thixotropy on a semiconductor substrate has improved shape stability, and the passivation layer is selectively formed at a desired position in a desired shape. Will be able to. Therefore, in the composition for forming a passivation layer containing water, at least one of a thixotropic agent and a resin (hereinafter, at least one of the thixotropic agent and the resin may be referred to as a thixotropic agent) in order to express desired thixotropic properties. Even if a thixotropic agent or the like is used, the amount of addition can be reduced as compared with the conventional passivation layer forming composition.
  • the thixotropic agent When forming a passivation layer using a composition for forming a passivation layer containing a thixotropic agent composed of an organic substance, the thixotropic agent is thermally decomposed and scattered from the passivation layer through a degreasing process. Become. However, a thermal decomposition product such as a thixotropic agent may remain as an impurity in the passivation layer even after a degreasing process, and the remaining thermal decomposition product such as a thixotropic agent may affect the characteristics of the passivation layer.
  • the thixotropic agent when forming a passivation layer using a composition for forming a passivation layer containing a thixotropic agent composed of an inorganic substance, the thixotropic agent may not be scattered and remain in the passivation layer even after a heat treatment (firing) step. is there. The remaining thixotropic agent may affect the properties of the passivation layer.
  • the hydrolyzate of water or the alkoxy compound behaves as a thixotropic agent.
  • Water is more likely to scatter from the passivation layer than a conventional thixotropic agent or the like in a heat treatment (firing) step or the like that is performed when the passivation layer is formed using the passivation layer forming composition. For this reason, it is difficult to cause a decrease in the passivation effect of the passivation layer due to the presence of the residue in the passivation layer.
  • the composition for forming a passivation layer contains water, it is possible to form a passivation layer having excellent pattern forming properties and excellent passivation effect by a simple technique. Moreover, a passivation layer having a desired shape can be formed by using a composition for forming a passivation layer having excellent pattern formability. This makes it possible to manufacture an excellent semiconductor substrate with a passivation layer, a solar cell element, and a solar cell.
  • the water state may be solid or liquid. From the viewpoint of miscibility with the alkoxy compound, water is preferably a liquid.
  • the content of water contained in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the water content is preferably, for example, 0.01% by mass or more with respect to the total mass of the composition for forming a passivation layer.
  • the content is more preferably 03% by mass or more, further preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more.
  • the content rate of water is 80 mass% or less with respect to the total mass of the composition for passivation layer formation from a viewpoint of pattern formation property and a passivation effect, for example, and it is 70 mass% or less. Is more preferably 60% by mass or less, and particularly preferably 50% by mass or less.
  • the amount of water that has acted on the alkoxy compound in the composition for forming a passivation layer can be calculated from the amount of alcohol or carboxylic acid liberated from the alkoxy compound.
  • alcohol or carboxylic acid is liberated from the alkoxy compound.
  • the amount of the released alcohol or carboxylic acid is proportional to the number of functional groups of the alkoxy compound to which water has acted. Therefore, the amount of water that has acted on the alkoxy compound can be calculated by measuring the amount of the liberated alcohol or carboxylic acid. Measurement of the amount of liberated alcohol or carboxylic acid can be confirmed using, for example, gas chromatography mass spectrometry (GC-MS).
  • GC-MS gas chromatography mass spectrometry
  • the content of alcohol or carboxylic acid contained in the composition for forming a passivation layer is, for example, preferably 0.5% by mass to 70% by mass, more preferably 1% by mass to 60% by mass. More preferably, the content is from 50% by mass to 50% by mass.
  • the composition for forming a passivation layer may contain at least one hydrolyzate of an aluminum oxide precursor, and may contain at least one hydrolyzate of a silicon compound, as necessary.
  • at least one hydrolyzate of the compound of the formula (1) may be contained, and at least one hydrolyzate of the compound of the formula (2) may be contained.
  • the hydrolyzate of the aluminum oxide precursor may contain a dehydration condensate of the hydrolyzate of the aluminum oxide precursor, and the hydrolyzate of the silicon compound includes dehydration of the hydrolyzate of the silicon compound.
  • a condensate may be contained, and the hydrolyzate of the compound of formula (1) may contain a dehydration condensate of the hydrolyzate of the compound of formula (1).
  • the decomposition product may contain a dehydration condensate of the hydrolysis product of the compound of formula (2).
  • the content of the aluminum oxide precursor is the total content of the aluminum oxide precursor and the hydrolyzate of the aluminum oxide precursor in the composition for forming the passivation layer.
  • the content of the silicon compound is the total content of the silicon compound and the hydrolyzate of the silicon compound in the composition for forming the passivation layer.
  • the content of the compound of formula (1) is the total content of the compound (1) and the hydrolyzate of the compound of formula (1) in the composition for forming a passivation layer.
  • the content of the compound of the formula (2) is the total content of the compound (2) and the hydrolyzate of the compound of the formula (2) in the composition for forming the passivation layer. Rate.
  • the composition for forming a passivation layer may further contain at least one of an acidic compound and a basic compound.
  • an acidic compound or a basic compound from the viewpoint of storage stability, the content of the acidic compound or the basic compound is, for example, relative to the total mass of the composition for forming a passivation layer Each of them is preferably 1% by mass or less, and more preferably 0.1% by mass or less.
  • acidic compounds include Bronsted acid and Lewis acid. Specific examples include inorganic acids such as hydrochloric acid and nitric acid; organic acids such as acetic acid.
  • basic compounds include Bronsted bases and Lewis bases.
  • the basic compound include inorganic bases such as alkali metal hydroxides and alkaline earth metal hydroxides, and organic bases such as trialkylamine and pyridine.
  • the composition for forming a passivation layer of the present embodiment may further contain other components that are usually used in the field as necessary, in addition to the above-described components.
  • Other components include, for example, organic fillers, inorganic fillers, thixotropic agents such as organic acid salts, wettability improvers, leveling agents, surfactants, plasticizers, fillers, antifoaming agents, stabilizers, and oxidation.
  • flavor are mentioned.
  • the content of the other components is not particularly limited.
  • each component is added to each of 0.1 parts by mass with respect to 100 parts by mass of the total composition for forming a passivation layer. It may be used in an amount of about 01 to 20 parts by mass.
  • Other components may be used individually by 1 type, and may use 2 or more types together.
  • the viscosity of the composition for forming a passivation layer is not particularly limited, and can be appropriately selected depending on a method for applying the composition to a semiconductor substrate.
  • the viscosity of the composition for forming a passivation layer can be 0.01 Pa ⁇ s to 10,000 Pa ⁇ s, and is preferably 0.1 Pa ⁇ s to 1000 Pa ⁇ s from the viewpoint of pattern formation.
  • the viscosity is measured with a rotary shear viscometer at 25 ° C. and a shear rate of 1.0 s ⁇ 1 .
  • the shear viscosity of the composition for forming a passivation layer is not particularly limited, and preferably has thixotropy. From the viewpoint of pattern formability, shear viscosity eta 1 at a shear rate of 1.0 s -1, thixotropic index is calculated by dividing the shear viscosity eta 2 at a shear rate of 10s -1 ( ⁇ 1 / ⁇ 2 ) is, For example, it is preferably 1.05 to 100, more preferably 1.1 to 50. In this specification, the shear viscosity is measured at a temperature of 25 ° C. using a rotary shear viscometer equipped with a cone plate (diameter 50 mm, cone angle 1 °).
  • shear viscosity eta 1 at a shear rate of 1.0 s -1 the shear viscosity at a shear rate of 1000 s -1 eta
  • the thixo ratio ( ⁇ 1 / ⁇ 3 ) calculated by dividing by 3 is, for example, preferably from 1.05 to 100, and more preferably from 1.1 to 50.
  • Method for producing a composition for forming a passivation layer There is no restriction
  • it can be produced by mixing an aluminum oxide precursor, a silicon compound, and a resin, a liquid medium, water, and the like contained as necessary by a commonly used mixing method.
  • a composition for forming a passivation layer containing a resin and a liquid medium is prepared, the resin is dissolved or dispersed in the liquid medium, and then the passivation layer is mixed with the aluminum oxide precursor and the silicon compound.
  • a forming composition may be produced.
  • the aluminum oxide precursor When a specific aluminum compound is used as the aluminum oxide precursor, it may be prepared by mixing an aluminum alkoxide and a compound capable of forming a chelate with aluminum. At that time, a liquid medium may be appropriately used or heat treatment may be performed.
  • the components contained in the composition for forming a passivation layer, and the content of each component can be determined by thermal analysis such as a differential thermal-thermogravimetric measuring device (TG / DTA), nuclear magnetic resonance (NMR), infrared spectroscopy ( It can be confirmed by spectral analysis such as IR), chromatographic analysis such as high performance liquid chromatography (HPLC), gel permeation chromatography (GPC) and the like.
  • thermal analysis such as a differential thermal-thermogravimetric measuring device (TG / DTA), nuclear magnetic resonance (NMR), infrared spectroscopy ( It can be confirmed by spectral analysis such as IR), chromatographic analysis such as high performance liquid chromatography (HPLC), gel permeation chromatography (GPC) and the like.
  • the semiconductor substrate with a passivation layer of the present embodiment includes a semiconductor substrate and a passivation layer that is a heat treatment product of the composition for forming a passivation layer of the present embodiment provided on at least a part of at least one surface of the semiconductor substrate.
  • the semiconductor substrate with a passivation layer may further include other components as necessary.
  • the semiconductor substrate with a passivation layer exhibits an excellent passivation effect by having a passivation layer that is a heat-treated product of the composition for forming a passivation layer of the present embodiment.
  • the semiconductor substrate is not particularly limited, and can be appropriately selected from those usually used according to the purpose.
  • the semiconductor substrate for example, a substrate made of silicon, germanium, or the like, doped (diffused) with p-type impurities or n-type impurities can be used.
  • the semiconductor substrate is preferably a silicon substrate. Further, the semiconductor substrate may be a p-type semiconductor substrate or an n-type semiconductor substrate. From the viewpoint of the passivation effect, the surface on which the passivation layer is formed is preferably a semiconductor substrate having a p-type layer.
  • the p-type layer on the semiconductor substrate is a p-type layer derived from the p-type semiconductor substrate
  • the p-type layer is formed on the n-type semiconductor substrate or the p-type semiconductor substrate as a p-type diffusion layer or a p + -type diffusion layer. It may be a thing.
  • the thickness of the semiconductor substrate is not particularly limited and can be appropriately selected according to the purpose.
  • the thickness of the semiconductor substrate can be 50 ⁇ m to 1000 ⁇ m, preferably 75 ⁇ m to 750 ⁇ m.
  • the thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and can be appropriately selected depending on the purpose.
  • the average thickness of the passivation layer is preferably 200 nm or less, more preferably 5 nm to 200 nm, still more preferably 10 nm to 190 nm, and particularly preferably 15 nm to 180 nm.
  • the average thickness of the formed passivation layer is calculated as an arithmetic average value by measuring the thickness at nine points by an ordinary method using an automatic ellipsometer (for example, MARY-102 manufactured by Fibrabo).
  • the content of silicon element in the passivation layer is preferably 0.01 atm% or more, more preferably 0.05 atm% or more, further preferably 0.1 atm% or more, and 0.2 atm%. The above is particularly preferable.
  • the content of silicon element in the passivation layer is, for example, preferably 0.01% by mass to 40% by mass, more preferably 0.1% by mass to 35% by mass, and 0.5% by mass to 30% by mass. More preferably, it is mass%.
  • the silicon element content in the passivation layer is determined by energy dispersive X-ray spectroscopy (EDX), secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), or high frequency inductively coupled plasma mass spectrometry ( ICP-MS).
  • EDX energy dispersive X-ray spectroscopy
  • SIMS secondary ion mass spectrometry
  • XPS X-ray photoelectron spectroscopy
  • ICP-MS high frequency inductively coupled plasma mass spectrometry
  • the semiconductor substrate with a passivation layer can be applied to solar cell elements, light emitting diode elements, and the like.
  • a solar cell element excellent in power generation performance can be obtained by applying to a solar cell element.
  • the passivation layer is preferably provided on the light receiving surface side of the solar cell element.
  • the method for manufacturing a semiconductor substrate with a passivation layer of the present embodiment includes a step of forming the composition layer by applying the passivation layer forming composition of the present embodiment to at least a part of at least one surface of the semiconductor substrate; Forming a passivation layer by heat-treating (sintering) the composition layer.
  • the manufacturing method may further include other steps as necessary.
  • the semiconductor substrate to which the composition for forming a passivation layer is applied those described in the above-described semiconductor substrate with a passivation layer can be used.
  • the method for producing a semiconductor substrate with a passivation layer preferably further includes a step of applying an alkaline aqueous solution on the semiconductor substrate before the step of forming the composition layer. That is, it is preferable to wash the surface of the semiconductor substrate with an alkaline aqueous solution before applying the composition for forming a passivation layer on the semiconductor substrate. By washing with an alkaline aqueous solution, organic substances, particles and the like present on the surface of the semiconductor substrate can be removed, and the passivation effect is further improved.
  • the semiconductor substrate can be immersed in a mixed solution of ammonia water and hydrogen peroxide solution and treated at 60 ° C. to 80 ° C. to remove organic substances and particles for cleaning.
  • the washing time is preferably 10 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes.
  • the method for forming the composition layer by applying the passivation layer forming composition on the semiconductor substrate is not particularly limited, and a known coating method or the like may be used. Specific examples include an immersion method, a printing method, a spin coating method, a dispenser method, a brush coating method, a spray method, a doctor blade method, a roll coating method, and an ink jet method. From the viewpoint of pattern formability, a printing method such as screen printing, an ink jet method and the like are preferable, and a screen printing method is more preferable.
  • the amount of the passivation layer forming composition applied to the semiconductor substrate can be appropriately selected depending on the purpose.
  • the thickness of the passivation layer to be formed can be appropriately adjusted so as to be the above-described desired thickness.
  • a passivation layer is formed on a semiconductor substrate by heat-treating (baking) the composition layer formed by the composition for forming a passivation layer to form a heat-treated material layer (baked material layer) derived from the composition layer.
  • the heat treatment (firing) conditions of the composition layer are not particularly limited as long as the aluminum oxide precursor contained in the composition layer can be converted into aluminum oxide (Al 2 O 3 ) that is the heat treated product (firing product).
  • the heat treatment (firing) conditions that can form an amorphous Al 2 O 3 layer having no specific crystal structure are preferable.
  • the heat treatment (firing) temperature is preferably 400 ° C. to 900 ° C., more preferably 450 ° C. to 800 ° C.
  • the heat treatment (firing) time can be appropriately selected according to the heat treatment (firing) temperature and the like. For example, it is preferably 30 seconds to 10 hours, and more preferably 1 minute to 5 hours.
  • a method for manufacturing a semiconductor substrate with a passivation layer is obtained by applying a composition for forming a passivation layer to a semiconductor substrate to form a composition layer, and then forming the composition layer before the step of forming the passivation layer by heat treatment (firing). You may have further the process of drying. By having a process of drying the composition layer, a passivation layer having a more uniform thickness tends to be formed.
  • the step of drying the composition layer is not particularly limited as long as at least a part of the liquid medium and water that may be contained in the composition for forming a passivation layer can be removed.
  • the drying treatment is preferably a heat treatment at 30 ° C. to 600 ° C. for 5 seconds to 60 minutes, and more preferably a heat treatment at 40 ° C. to 450 ° C. for 30 seconds to 40 minutes.
  • the drying treatment may be performed under normal pressure or under reduced pressure.
  • the method for manufacturing a semiconductor substrate with a passivation layer includes forming the composition layer by applying the composition for forming a passivation layer, and then forming the passivation layer by heat treatment (firing). You may further have the process of degreasing a composition layer before a process. By having a step of degreasing the composition layer, a passivation layer having a more uniform passivation effect can be formed.
  • the step of degreasing the composition layer is not particularly limited as long as at least part of the resin that may be contained in the composition for forming a passivation layer can be removed.
  • the degreasing treatment is preferably, for example, a heat treatment at 30 ° C. to 600 ° C. for 5 seconds to 60 minutes, and more preferably a heat treatment at 40 ° C. to 450 ° C. for 30 seconds to 40 minutes.
  • the degreasing treatment is preferably performed in the presence of oxygen, and more preferably performed in the atmosphere.
  • the solar cell element according to the present embodiment includes a semiconductor substrate having a pn junction part in which a p-type layer and an n-type layer are pn-junction, and at least a part of at least one surface of the semiconductor substrate.
  • the solar cell element may further include other components as necessary.
  • the solar cell element of this embodiment is excellent in power generation performance by having the passivation layer formed from the composition for forming a passivation layer of this embodiment.
  • the details of the semiconductor substrate used in the solar cell element are the same as those of the semiconductor substrate with a passivation layer described above, and the preferred embodiments are also the same.
  • the thickness of the passivation layer in the solar cell element is not particularly limited, and is the same as that of the semiconductor substrate with a passivation layer described above, and the preferred embodiment is also the same.
  • the method for manufacturing a solar cell element of this embodiment is for forming a passivation layer of this embodiment on at least a part of at least one surface of a semiconductor substrate having a pn junction part formed by joining a p-type layer and an n-type layer.
  • the method for manufacturing a solar cell element may further include other steps as necessary.
  • an electrode can be produced by applying an electrode forming paste such as a silver paste or an aluminum paste to a desired region of a semiconductor substrate and performing a heat treatment (firing) as necessary.
  • the surface of the semiconductor substrate on which the passivation layer is provided may be a p-type layer or an n-type layer. From the viewpoint of power generation performance, the surface of the semiconductor substrate is preferably a p-type layer.
  • the details of the method for forming a passivation layer using the composition for forming a passivation layer of the present embodiment are the same as those of the method for manufacturing a semiconductor substrate with a passivation layer described above, and the preferred embodiments are also the same.
  • the manufacturing method of the solar cell element of this embodiment will be described with reference to the drawings, but the present invention is not limited to this.
  • size of the member in each figure is notional, The relative relationship of the magnitude
  • symbol is attached
  • FIG. 1 is a cross-sectional view schematically showing an example of a method for producing a solar cell element having a passivation layer.
  • this process diagram does not limit the present invention at all.
  • the p-type semiconductor substrate 1 is washed with an alkaline aqueous solution to remove organic substances, particles and the like on the surface of the p-type semiconductor substrate 1. Thereby, the passivation effect improves more.
  • a cleaning method using an alkaline aqueous solution a method using generally known RCA cleaning and the like can be mentioned.
  • the surface of the p-type semiconductor substrate 1 is subjected to alkali etching or the like to form irregularities (also referred to as a texture structure) on the surface.
  • irregularities also referred to as a texture structure
  • reflection of sunlight can be suppressed on the light receiving surface side.
  • alkali etching an etching solution composed of NaOH and IPA (isopropyl alcohol) can be used.
  • an n + -type diffusion layer 2 is formed with a thickness on the order of submicrons, and p A pn junction is formed at the boundary with the mold bulk portion.
  • a method for diffusing phosphorus for example, there is a method of performing treatment for several tens of minutes at 800 ° C. to 1000 ° C. in a mixed gas atmosphere of phosphorus oxychloride (POCl 3 ), nitrogen, and oxygen.
  • POCl 3 phosphorus oxychloride
  • a diffusion layer 2 is formed.
  • a PSG (phosphosilicate glass) layer 3 is formed on the n + -type diffusion layer 2. Therefore, side etching is performed to remove the side PSG layer 3 and the n + -type diffusion layer 2.
  • the PSG layer 3 on the light receiving surface and the back surface is removed using an etching solution such as hydrofluoric acid. Further, as shown in FIG. 1 (5), the back surface is separately etched to remove the n + -type diffusion layer 2 on the back surface.
  • an antireflection film 4 made of silicon nitride or the like is provided on the n + -type diffusion layer 2 on the light-receiving surface by a plasma CVD (PECVD) method or the like with a thickness of about 90 nm.
  • PECVD plasma CVD
  • the back surface may be flattened using an aqueous alkali solution such as NaOH.
  • a passivation layer forming composition is applied to a part of the back surface by a screen printing method or the like, followed by heat treatment (baking) at 300 ° C. to 900 ° C. after drying. Layer 5 is formed.
  • FIG. 5 is a schematic plan view showing an example of the formation pattern of the passivation layer on the back surface.
  • FIG. 7 is an enlarged schematic plan view of a portion A in FIG.
  • FIG. 8 is an enlarged schematic plan view of a portion B in FIG.
  • the passivation layer 5 on the back surface is a dot-like pattern except for a portion where the back surface output extraction electrode 7 is formed in a later step. Formed with.
  • the pattern of the dot-shaped openings is defined by the dot diameter (La) and the dot interval (Lb), and is preferably arranged regularly.
  • the dot diameter (La) and the dot interval (Lb) can be arbitrarily set. From the viewpoint of suppressing the passivation effect and the recombination of minority carriers, it is preferable that La is 5 ⁇ m to 2 mm and Lb is 10 ⁇ m to 3 mm. It is more preferable that Lb is 10 ⁇ m to 1.5 mm and Lb is 20 ⁇ m to 2.5 mm, and more preferable that La is 20 ⁇ m to 1.3 mm and Lb is 30 ⁇ m to 2 mm.
  • the dot-shaped opening pattern is more regularly arranged in terms of dot diameter (La) and dot interval (Lb). For this reason, recombination of minority carriers is effectively suppressed, and the power generation performance of the solar cell element is improved.
  • FIG. 9 is an enlarged schematic plan view of a portion A in FIG.
  • FIG. 10 is an enlarged schematic plan view of a portion B in FIG.
  • the passivation layer 5 on the back surface is p-type in a line shape except for a portion where the back surface output extraction electrode 7 is formed in a later step.
  • the semiconductor substrate 1 is formed with an exposed pattern.
  • the pattern of the line openings is defined by the line width (Lc) and the line interval (Ld), and is preferably arranged regularly.
  • the line width (Lc) and the line interval (Ld) can be set arbitrarily, but from the viewpoint of suppressing the passivation effect and minority carrier recombination, for example, it is preferable that Lc is 1 ⁇ m to 300 ⁇ m and Ld is 500 ⁇ m to 5000 ⁇ m. More preferably, Lc is 10 ⁇ m to 200 ⁇ m, Ld is 600 ⁇ m to 3000 ⁇ m, Lc is 30 ⁇ m to 150 ⁇ m, and Ld is 700 ⁇ m to 1500 ⁇ m.
  • the composition for forming a passivation layer has an excellent pattern forming property
  • the line width (Lc) and the line interval (Ld) are more regularly arranged in the pattern of the line-shaped openings. For this reason, recombination of minority carriers is effectively suppressed, and the power generation efficiency of the solar cell element is improved.
  • the passivation layer having a desired shape is formed by applying the passivation layer-forming composition to a portion (portion other than the opening) where the passivation layer is to be formed and heat-treating (firing).
  • the passivation layer forming composition is applied to the entire surface, and after heat treatment (firing), the passivation layer in the opening can be selectively removed by laser, photolithography, or the like to form the opening.
  • the composition for forming a passivation layer can be selectively applied by previously masking a portion such as an opening where a composition for forming a passivation layer is not desired to be applied with a mask material.
  • FIG. 4 is a schematic plan view showing an example of the light receiving surface of the solar cell element.
  • the light receiving surface electrode includes a light receiving surface current collecting electrode 8 and a light receiving surface output extraction electrode 9.
  • the width of the light receiving surface current collecting electrode 8 is preferably 10 ⁇ m to 250 ⁇ m
  • the width of the light receiving surface output extraction electrode 9 is preferably 100 ⁇ m to 2 mm.
  • two light receiving surface output extraction electrodes 9 are provided.
  • the number of light receiving surface output extraction electrodes 9 may be three or more.
  • FIG. 11 is a schematic plan view showing an example of the back surface of the solar cell element.
  • the width of the back surface output extraction electrode 7 is not particularly limited, but the width of the back surface output extraction electrode 7 is preferably 100 ⁇ m to 10 mm from the viewpoint of the connectivity of the wiring members in the subsequent manufacturing process of the solar cell.
  • the glass particles contained in the silver electrode paste forming the light receiving surface electrode react with the antireflection film 4 (fire through),
  • the light-receiving surface electrode (light-receiving surface current collecting electrode 8, light-receiving surface output extraction electrode 9) and the n + -type diffusion layer 2 are electrically connected (ohmic contact).
  • the rear surface the portion where the passivation layer 5 of the dot-like or line-like is not formed, by heat treatment (sintering), that the aluminum in the aluminum electrode paste diffuses into the p-type semiconductor substrate 1, p + -type A diffusion layer 10 is formed.
  • FIG. 2 is a cross-sectional view schematically showing another example of a method for manufacturing a solar cell element.
  • the back surface is further removed.
  • the solar cell element can be manufactured in the same manner as in FIG. 1 except that is flattened.
  • a technique such as immersing the back surface of the semiconductor substrate in a mixed solution of nitric acid, hydrofluoric acid, and acetic acid or a potassium hydroxide solution can be used.
  • FIG. 3 is a cross-sectional view schematically showing another example of a method for manufacturing a solar cell element. This method is the same as the method of FIG. 1 until the step of forming the texture structure, the n + -type diffusion layer 2 and the antireflection film 4 on the p-type semiconductor substrate 1 (FIGS. 3 (19) to (24)). is there.
  • FIG. 6 shows a schematic plan view of another example of the formation pattern of the passivation layer on the back surface.
  • openings are arranged on the entire back surface, and openings are also arranged on the portion where the back surface output extraction electrode is formed in a later step.
  • boron or aluminum is diffused from the portion where the dot-like or line-like passivation layer 5 is not formed on the back surface, and the p + -type diffusion layer 10 is formed.
  • a method of treating at a temperature around 1000 ° C. in a gas containing boron trichloride (BCl 3 ) can be used.
  • the gas diffusion method is the same as in the case of using phosphorus oxychloride, the p + -type diffusion layer 10 is formed on the light-receiving surface, the back surface, and the side surface of the p-type semiconductor substrate 1. Therefore, it is necessary to take measures such as masking the portions other than the openings to prevent boron from diffusing into unnecessary portions of the p-type semiconductor substrate 1.
  • the p + -type diffusion layer 10 when aluminum is diffused when forming the p + -type diffusion layer 10, an aluminum paste is applied to the entire back surface or the opening, and this is heat-treated (fired) at 450 ° C. to 900 ° C.
  • the p + -type diffusion layer 10 can be formed by diffusing, and then a heat-treated product layer (baked product layer) made of an aluminum paste on the p + -type diffusion layer 10 can be etched with hydrochloric acid or the like.
  • the aluminum electrode 11 for backside current collection is formed by physically depositing aluminum on the entire backside.
  • a silver electrode paste containing glass particles is applied to the light receiving surface by screen printing or the like, and a silver electrode paste containing glass particles is applied to the back surface by a screen printing method or the like.
  • the silver electrode paste on the light receiving surface is applied in a pattern according to the shape of the light receiving surface electrode shown in FIG. 4, and the silver electrode paste on the back surface is applied in a pattern according to the shape of the back electrode shown in FIG.
  • the light receiving surface and the back surface are heat-treated (fired) at a temperature of about 450 ° C. to 900 ° C. in air, as shown in FIG.
  • a light receiving surface collecting electrode 8 and a light receiving surface output extraction electrode 9 are formed on the light receiving surface, and a back surface output extraction electrode 7 is formed on the back surface.
  • the light receiving surface electrode and the n + -type diffusion layer 2 are electrically connected, and on the back surface, the back surface collecting aluminum electrode 11 and the back surface output extraction electrode 7 formed by vapor deposition are electrically connected. Connected.
  • the passivation layer is formed after forming the back surface collecting aluminum electrode 6 or 11. 5 may be formed.
  • the passivation layer forming composition is applied to the side surface in addition to the back surface of the p-type semiconductor substrate 1, and this is subjected to heat treatment (
  • the passivation layer 5 may be further formed on the side surface (edge) of the p-type semiconductor substrate 1 by baking (not shown).
  • the passivation layer 5 may be formed by applying the composition for forming a passivation layer of the present embodiment only on the side surface and drying.
  • FIGS. 1 to 3 show an example in which the p-type semiconductor substrate 1 is used as the semiconductor substrate. However, even when an n-type semiconductor substrate is used, a solar cell element having excellent power generation performance can be manufactured according to the above. .
  • the solar cell of the present embodiment includes at least one of the solar cell elements of the present embodiment, and is configured by arranging a wiring material on the electrode of the solar cell element. That is, the solar cell of this embodiment has the solar cell element and a wiring material disposed on the electrode of the solar cell element. If necessary, the solar cell may have a plurality of solar cell elements connected via a wiring material, or may be configured to be 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.
  • the size of the solar cell is not limited and is preferably 0.5 m 2 to 3 m 2 .
  • FIG. 12 shows an example of the structure of a solar cell.
  • the glass plate 16, the sealing material 14, the solar cell element 12 to which the wiring material 13 is connected, the sealing material 14, and the back sheet 15 are superposed in this order.
  • This is vacuum-laminated using a vacuum laminator (for example, LM-50 ⁇ 50, NPC Corporation) so that a part of the wiring member 13 is exposed, and a solar cell is manufactured.
  • a vacuum laminator for example, LM-50 ⁇ 50, NPC Corporation
  • Example 1> Preparation of a composition for forming a passivation layer
  • 12.0 g of aluminum ethyl acetoacetate diisopropylate manufactured by Kawaken Fine Chemical Co., Ltd., hereinafter abbreviated as ALCH
  • 5.0 g of ethyl silicate and its oligomer Teama Chemical Co., Ltd., silicate 40
  • Tersolve isobornyl 58.0 g of cyclohexanol
  • Tersolve 22.5 g of terpineol
  • Terpineol LW terpineol
  • pure water and kneaded for 5 minutes A composition 1 for forming a passivation layer was prepared.
  • composition 1 for forming a passivation layer obtained above was screen-printed on a silicon substrate (a single-crystal p-type silicon substrate having a mirror shape on the surface, manufactured by SUMCO Corporation, 50 mm square, thickness: 725 ⁇ m). And coated on the entire surface to form a composition layer. The printing of the silicon substrate was continuously performed 10 sheets.
  • the applicability was evaluated by visually confirming the presence or absence of printing unevenness and the number of silicon substrates on which printing unevenness was not confirmed.
  • the evaluation criteria of applicability are as follows. If evaluation was A and B, it was judged that applicability was good.
  • the printing unevenness refers to a state in which the thickness of the composition layer is uneven due to partial poor plate separation when the screen plate is separated from the silicon substrate.
  • the composition 1 for forming a passivation layer was applied to a silicon substrate by the same method as the evaluation of applicability. Then, after drying at 180 ° C. for 2 minutes and then baking at 800 ° C. for 10 minutes, the substrate was allowed to cool at room temperature (25 ° C.) to produce an evaluation substrate.
  • the effective lifetime ( ⁇ s) of the evaluation substrate obtained above was measured by a reflected microwave photoconductive decay method at room temperature (25 ° C.) using a lifetime measurement device (Nippon Semilab Co., Ltd., WT-2000PVN). .
  • substrate was 280 microseconds.
  • the evaluation criteria for effective lifetime are as follows. If evaluation was A and B, it was judged that the effective lifetime was favorable.
  • A 200 ⁇ s or more
  • B Less than 200 ⁇ s and 100 ⁇ s or more
  • C Less than 100 ⁇ s
  • evaluation substrate obtained above was cross-sectional processed by ion milling and observed with a transmission electron microscope (Hitachi High-Technologies Corporation, H-9000NAR). The observation image was visually checked for the presence or absence of contrast.
  • the evaluation criteria for denseness are as follows. If evaluation was A and B, it was judged that denseness was favorable.
  • Example 2 > 12.0 g of ALCH, 0.5 g of ethyl silicate and its oligomer (Tama Chemical Co., Ltd., Silicate 40), 6.0 g of ethyl cellulose (Dow Chemical Co., STD200) and 81.5 g of terpineol are mixed and kneaded for 5 minutes. Then, a composition 2 for forming a passivation layer was prepared. A passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the composition 2 for forming a passivation layer was used, and evaluation was performed in the same manner. The results are shown in Table 1.
  • Example 3 12.0 g of ALCH, 5.0 g of 3-acryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., KBM-5103), 58.0 g of tersolve, 22.5 g of terpineol, and 2.5 g of pure water were mixed. And kneading for 5 minutes to prepare a composition 3 for forming a passivation layer.
  • a passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the composition 3 for forming a passivation layer was used, and evaluation was performed in the same manner. The results are shown in Table 1.
  • Example 4 12.0 g of ALCH, 10.0 g of ethyl silicate and its oligomer (Tama Chemical Co., Ltd., silicate 40), 58.0 g of tersolve, 17.5 g of terpineol, 2.5 g of pure water and kneaded for 5 minutes Then, a passivation layer forming composition 4 was prepared. A passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the composition 4 for forming a passivation layer was used, and evaluation was performed in the same manner. The results are shown in Table 1.
  • Example 5 12.0 g of ALCH, 20.0 g of ethyl silicate and its oligomer (Tama Chemical Co., Ltd., Silicate 40), 55.0 g of tersolve, 10.5 g of terpineol, 2.5 g of pure water, and kneaded for 5 minutes. Then, a composition 5 for forming a passivation layer was prepared. A passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the composition 5 for forming a passivation layer was used, and evaluation was performed in the same manner. The results are shown in Table 1.
  • Example 6 > 12.0 g of ALCH, 30.0 g of ethyl silicate and its oligomer (Tama Chemical Co., Ltd., silicate 40), 50.0 g of tersolve, 5.5 g of terpineol, 2.5 g of pure water, and kneaded for 5 minutes. Then, a composition 6 for forming a passivation layer was prepared. A passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the passivation layer forming composition 6 was used, and evaluation was performed in the same manner. The results are shown in Table 1.
  • a composition 7 for forming a passivation layer was prepared by mixing 12.0 g of ALCH, 60.0 g of tersolve, 25.5 g of terpineol and 2.5 g of pure water and kneading for 5 minutes.
  • a passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the passivation layer forming composition 7 was used, and evaluation was performed in the same manner. The results are shown in Table 1.
  • a passivation layer having an excellent passivation effect can be formed by using the composition for forming a passivation layer of Examples 1 to 6. It can also be seen that the passivation layer forming compositions of Examples 1 to 3 are excellent in coating properties. Furthermore, it can be seen that the passivation layers formed using the compositions for forming a passivation layer of Examples 1 to 6 are excellent in denseness with reduced generation of voids. Furthermore, it can be seen that the method using the composition for forming a passivation layer of Examples 1 to 6 can form a passivation layer having a desired shape by a simple method.
  • 1 p-type semiconductor substrate
  • 2 n + -type diffusion layer
  • 3 PSG (phosphorus silicate glass) layer
  • 4 antireflection film
  • 5 passivation layer
  • 6 aluminum electrode paste, or heat-treated (fired)
  • 7 Back surface output extraction electrode paste, or back surface output extraction electrode obtained by heat treatment (baking)
  • 8 Light receiving surface current collection electrode paste, or light receiving surface current collection obtained by heat treatment (firing)
  • 10 p + type diffusion layer
  • 11 aluminum electrode for backside current collection
  • 12 solar cell element
  • 13 Wiring member
  • 14 Sealing material
  • 15 Back sheet
  • 16 Glass plate

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Abstract

Cette composition de formation de couche de passivation contient un précurseur d'oxyde d'aluminium et un composé de silicium.
PCT/JP2016/086248 2016-06-28 2016-12-06 Composition de formation de couche de passivation, substrat semi-conducteur à couche de passivation, procédé de fabrication de substrat semi-conducteur à couche de passivation, élément de cellule solaire, procédé de fabrication d'élément de cellule solaire, et cellule solaire Ceased WO2018003141A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
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