JP2011139048A - Substrate for solar cell roughened in at least one surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for a solar cell having a texture structure attaining low reflectance regardless of use of a polycrystalline or amorphous material. <P>SOLUTION: The substrate for the solar cell roughened in at least one surface is obtained by exposing the substrate in which a thin film containing at least one kind of organic compounds having N-F coupling is entirely or partially formed on at least one surface to light from the thin film side and then removing the thin film together with residue between the thin film and the substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solar cell substrate having at least one surface roughened.

  Solar cells are the most important technology as a countermeasure against global warming these days, and are currently focused on development. Efficiency improvement measures in the development of solar cells are very important, but since there are limits to the efficiency improvement by materials, measures for improving the efficiency of the entire device are being studied.

  As a measure for improving the efficiency, it is known that if the light absorption efficiency on the light receiving surface of the device is improved, the efficiency can be greatly improved. For this reason, the light confinement effect due to the optimization of the surface texture structure has attracted attention, and the formation method of this texture structure has been energetically studied.

  At present, development of a thin film solar cell using amorphous silicon is being actively studied because it is more advantageous than a single crystal silicon solar cell in terms of energy and cost, and can further increase the area. However, there is a problem that both durability and power generation efficiency are low, and measures for improving efficiency are particularly important.

  Information on texture structures that can efficiently absorb light has become popular due to improvements in calculation methods. On the other hand, a pyramidal texture is known as an antireflection surface structure that has been most often used so far. This shape is used because, in the single-crystal silicon solar cells that have been studied for the longest time, anisotropic etching of the (100) plane with alkali has progressed, and as a result, a pyramidal texture structure can be easily formed. It is. For this reason, there are very few practical antireflection surface processing methods other than this texture structure.

  The texture structure formation methods that have been studied are roughly classified into wet etching processes (one using an alkaline solution (Patent Document 1), one using an acidic solution (Non-Patent Documents 1 to 3)), a dry etching process ( Plasma dry etching method (patent documents 2 to 8, non-patent documents 4 to 5), plasmaless dry etching method (non-patent document 6), sputtering method (patent document 9), laser patterning (non-patent document 7)), machine Typical polishing processes (Non-Patent Documents 8 to 9) and the like. Also, it has been studied to create an optimum shape by combining a plurality of these methods (Patent Documents 10 to 11).

  However, since the dry process is the same as the semiconductor manufacturing process, it is possible to create a precise surface shape. However, since the apparatus is expensive, it cannot cope with an increase in area. In addition, since high energy is used, particularly plasma and laser beams, the device is damaged during the surface treatment.

  On the other hand, the wet etching method is the most popular method. However, the principle of texture structure formation is that this wet etching method is anisotropically etched according to the crystal orientation of a material such as silicon. Therefore, taking a silicon solar cell as an example, it can be applied only to a single crystal silicon solar cell using a wafer having a (100) plane. That is, it cannot be applied to a solar cell using a polycrystalline or amorphous material.

  As described above, the conventional method cannot form an appropriate texture structure particularly in a solar cell using a polycrystalline or amorphous material. Accordingly, there is a demand for a technique for processing an antireflection texture structure that can be generally and easily applied to all types of solar cells including solar cells using polycrystalline or amorphous materials.

JP 2000-183378 A JP 2000-012517 A JP 2002-353484 A JP 2003-197940 A JP 05-0775152 A JP 09-102625 A Japanese Patent Application Laid-Open No. 11-312665 Japanese Patent Publication No. 60-027195 Japanese Patent Laid-Open No. 06-204536 JP 2000-101111 A JP 2004-235274 A

Panek et al., Journal of Materials Science, 2005, 40, 1459. Nishimoto et al., Journal of the Electrochemical Society, 1999, 146, 457. Matsumura et al., Solar Energy Materials and Solar Cells, 2006, 90, 100 J. Yoo et al., Journal of Physics D: Applied Physics, 2008, 41, 125205 Inomata et al., Solar Energy Materials and Solar Cells, 1997, 48, 237. Saito et al., Seikei University Science and Engineering Research Report, 2007, 44, 43 Kiyama et al., Japan Society for Precision Engineering, 1990, 56, 2069 Machida et al., Solar Energy Materials and Solar Cells, 1997, 48, 243. Nomoto et al., Sharp Technical Report, April 1998, p. 40

  An object of the present invention is to provide a solar cell substrate having a texture structure capable of achieving a low reflectance even when a polycrystalline or amorphous material is used as well as a solar cell made of single crystal silicon. To do.

In order to solve the above-mentioned problems, the present inventors have conducted intensive research, and as a result, exposed a substrate on which a thin film containing at least one organic compound having an NF bond is formed at least on one side or in part. Then, by removing the thin film together with the residue between the thin film and the substrate, a texture structure that can achieve low reflectance even when using a polycrystalline or amorphous material as well as single crystal silicon. The present inventors have found that a solar cell substrate can be provided and have completed the present invention. Of course, the technique of the present invention is not limited to a polycrystalline material and an amorphous material, but can be effectively used in a single crystal silicon solar cell as well. That is, the present invention has the following configuration.
Item 1. A substrate in which a thin film containing at least one organic compound having an N—F bond is formed on at least one side of the whole or a part thereof is obtained, and then the thin film is removed together with a residue between the thin film and the substrate. A solar cell substrate having at least one surface roughened.
Item 2. Item 2. The solar cell substrate according to item 1, wherein the organic compound having an NF bond has a structural unit represented by formula (1).

(Where

Is the conjugate base of Bronsted acid. )
Item 3. Item 3. The solar cell substrate according to item 1 or 2, wherein the organic compound having an NF bond is represented by formula (A1), (A2), or (A3).

[In formulas (A1) to (A3), adjacent R ¹ and R ² , R ² and R ³ , R ³ and R ^4, or R ⁴ and R ⁵ are linked, and —CR ⁶ = CR ⁷ -CR ⁸ ═CR ⁹ —, and R ¹ ′ and R ² ′, R ² ′ and R ³ ′, R ³ ′ and R ⁴ ′ or R ⁴ ′ and R ⁵ ′ are linked, ^{-CR 6 '= CR 7' -CR} 8 '= CR 9' - may be in the ^{form, R 1, R 2, R} 3, R 4, R 5, R 6, R 7, R 8, R ⁹ , R ¹ ′, R ² ′, R ³ ′, R ⁴ ′, R ⁵ ′, R ⁶ ′, R ⁷ ′, R ⁸ ′ and R ⁹ ′ are the same or different and all are hydrogen atoms; halogen Nitro group; hydroxy group; cyano group; carbamoyl group; halogen atom, hydroxyl group, alkoxy group having 1 to 5 carbon atoms, aryloxy group having 6 to 10 carbon atoms, acyl group having 1 to 5 carbon atoms, 1 carbon atom An alkyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of an acyloxy group having 5 and an aryl group having 6 to 10 carbon atoms; a halogen atom and an aryl group having 6 to 10 carbon atoms An alkenyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of: a group having at least one selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms A good alkynyl group having 1 to 15 carbon atoms; an aryl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms; at least one kind An acyl group having 1 to 15 carbon atoms which may be substituted with a halogen atom; a small amount selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms Or an optionally substituted alkoxycarbonyl group having 2 to 15 carbon atoms; a carbon atom having 7 carbon atoms that may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms. An aryloxycarbonyl group having 15 to 15 carbon atoms; an alkylsulfonyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms; a halogen atom and a carbon number An arylsulfonyl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of 1 to 5 alkyl groups; at least selected from the group consisting of halogen atoms and aryl groups having 6 to 10 carbon atoms C1-C15 alkyl sulfinyl group which may be substituted by 1 type; A halogen atom and a C1-C5 alkyl group An arylsulfinyl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of: a halogen atom and at least one selected from the group consisting of aryl groups having 6 to 10 carbon atoms An optionally substituted alkoxy group having 1 to 15 carbon atoms; an aryloxy group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms; An acyloxy group having 1 to 15 carbon atoms which may be substituted with one halogen atom; an acylthio group having 1 to 15 carbon atoms which may be substituted with at least one halogen atom; a halogen atom and 6 to 6 carbon atoms An alkanesulfonyloxy group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of 10 aryl groups; Arylsulfonyloxy group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a rogen atom and an alkyl group having 1 to 5 carbon atoms; an alkyl group having 1 to 5 carbon atoms and 6 carbon atoms A carbamoyl group optionally substituted with at least one selected from the group consisting of 10 to 10 aryl groups; may be substituted with at least one selected from the group consisting of an acyl group having 1 to 5 carbon atoms and a halogen atom A good amino group; an N-alkylpyridinium having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom, an aryl group having 6 to 10 carbon atoms and an alkyl group having 1 to 5 carbon atoms A base; substituted with at least one selected from the group consisting of a halogen atom, an aryl group having 6 to 10 carbon atoms and an alkyl group having 1 to 5 carbon atoms Which may N- aryl pyridinium base of carbon number 11 to 15; a or an organic polymer ^{chain, R 1, R 2, R} 3, R 4, R 5, R 6, R 7, R 8, R 9, R 1 ', R ² ', R ³ ', R ⁴ ', R ⁵ ', R ⁶ ', R ⁷ ', R ⁸ ' and R ⁹ 'can be combined in various combinations with or without a heteroatom. In formula (A2), one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ is

(R is a single bond or an alkylene group having 1 to 5 carbon atoms), and in the formula (A3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ One of R ¹ ′, R ² ′, R ³ ′, R ⁴ ′, R ⁵ ′, R ⁶ ′, R ⁷ ′, R ⁸ ′ and R ⁹ ′ with a single bond A chain is formed. Also,

Is the conjugate base of Bronsted acid. ]
Item 4. Item 4. The solar cell substrate according to Item 3, wherein in formula (A1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are the same or different, and each is a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. .
Item 5. In formulas (A1) and (A3),

Item 5. The solar cell substrate according to Item 3 or 4, wherein is a perfluoroalkanesulfonate.
Item 6. In formulas (A1) and (A3),

Item 5. The solar cell substrate according to Item 3 or 4, wherein is tetrafluoroborate.
Item 7. Item 7. The solar cell substrate according to any one of Items 1 to 6, wherein the thin film containing at least one organic compound having an NF bond further contains at least one ionic liquid.
Item 8. Item 8. The solar cell substrate according to any one of Items 1 to 7, wherein the substrate is a semiconductor or an insulator.
Item 9. Item 9. The solar cell substrate according to Item 8, wherein the semiconductor is a polycrystalline semiconductor or an amorphous semiconductor.
Item 10. Semiconductors are single crystal silicon, polycrystalline silicon, amorphous silicon, silicon carbide (SiC), germanium, silicon germanium, gallium arsenide, gallium aluminum arsenide, indium gallium arsenide, indium phosphide, indium antimony, copper indium selenium, copper indium gallium. Item 10. The solar cell substrate according to Item 8 or 9, which is at least one selected from the group consisting of selenium, indium tin oxide, cadmium tellurium, cadmium sulfide, zinc oxide, copper aluminum oxide, tin oxide, gallium nitride, and aluminum nitride.
Item 11. Item 8. The insulator is at least one selected from the group consisting of zirconium oxide, hafnium oxide, tantalum oxide, aluminum oxide, titanium oxide, chromium oxide, and silicates, silicon oxide, silicon nitride, and sapphire. The solar cell substrate described.
Item 12. A thin film containing at least one organic compound having an N—F bond is formed by spin coating, dipping, spraying, ink jetting, or doctor blade method so that the entire surface of the substrate has an N—F bond. Item 12. The solar cell substrate according to any one of Items 1 to 11, which is formed by applying a compound.
Item 13. Item 1-12, wherein the thin film containing at least one organic compound having an NF bond is formed by applying droplets made of an organic compound having an NF bond to the surface of the substrate by an inkjet method. The solar cell substrate according to any one of the above.
Item 14. Item 14. The solar cell substrate according to any one of Items 1 to 13, wherein the thin film containing at least one organic compound having an NF bond is crystalline, polycrystalline, amorphous, or liquid.
Item 15. Item 15. The solar cell substrate according to any one of Items 1 to 14, wherein the exposure is performed by irradiating visible light, ultraviolet rays, infrared rays, X-rays, electron beams, ion beams or laser beams.
Item 16. Item 16. The solar cell according to any one of Items 1 to 15, obtained by removing a thin film containing at least one organic compound having an NF bond and then wet-etching the surface of the substrate on which the thin film was formed. substrate.
Item 17. The method for producing a solar cell substrate according to any one of Items 1 to 16, wherein
(1) forming a thin film containing at least one organic compound having an NF bond on the surface of the substrate (2) exposing the substrate; and (3) forming the thin film between the thin film and the substrate. The manufacturing method of the board | substrate for solar cells including the process removed with a residue.
Item 18. After step (3)
(4) The method for producing a solar cell substrate according to item 17, including a step of performing wet etching on the surface of the substrate on which the thin film containing at least one organic compound having an NF bond is formed.
Item 19. Item 17. A solar cell comprising the solar cell substrate according to any one of Items 1 to 16.
Item 20. Item 17. A solar cell in which a thin film made of a semiconductor material is formed on the solar cell substrate according to any one of items 1 to 16.
Item 21. Item 11. A solar cell in which the solar cell substrate according to item 10 is formed on an insulating material or an electrode material.

  According to the present invention, it is possible to provide a solar cell substrate having a texture structure that can achieve low reflectance even when a polycrystalline or amorphous material is used as well as single crystal silicon.

It is a schematic sectional drawing which shows the manufacturing method of the board | substrate for solar cells in the 1st embodiment of this invention. It is a schematic sectional drawing which shows the manufacturing method of the board | substrate for solar cells in the 2nd embodiment of this invention. It is a schematic sectional drawing which shows the manufacturing method of the board | substrate for solar cells in the 3rd embodiment of this invention. It is a schematic sectional drawing which shows the manufacturing method of the board | substrate for solar cells in the 4th embodiment of this invention. It is a figure which shows the result of having observed the surface of the board | substrate for solar cells obtained in Example 1 with the phase shift interference microscope. It is a figure which shows the result of having observed the surface of the board | substrate for solar cells obtained in Example 2 with the phase shift interference microscope. It is a figure which shows the result of having observed the surface of the board | substrate for solar cells obtained in Example 3 with the phase shift interference microscope. It is a figure which shows the result of having observed the surface of the board | substrate for solar cells obtained in Example 4 with the phase shift interference microscope. It is a figure which shows the result of having observed the surface of the board | substrate for solar cells obtained in Example 5 with the phase shift interference microscope. It is a figure which shows the result of having observed the surface of the board | substrate for solar cells obtained in Example 6 with the phase shift interference microscope. In Example 6, it is the schematic which shows the experimental system which measured the light reflectivity. It is a figure which shows the result of having observed the surface of the board | substrate for solar cells obtained in Example 7 with the phase shift interference microscope. In addition, in FIG. 12, the middle figure and the lower figure are the figures which expanded the hole part of the upper figure.

1. Substrate for solar cell The substrate for solar cell having at least one surface roughened according to the present invention is a substrate on which a thin film containing at least one organic compound having an NF bond is formed on the entire surface or part of at least one surface. Is exposed, and then the thin film is removed together with the residue between the thin film and the substrate. In other words,
(1) A step of forming a thin film containing at least one organic compound having an NF bond on the surface of the substrate (2) a step of exposing the substrate from the thin film side; and (3) the thin film as the thin film It is obtained by a manufacturing method including a step of removing together with the residue between the substrate.

  In addition, in this invention, the board | substrate for solar cells is a concept including the back surface electrode which consists of an insulating material or an electrode material, the semiconductor thin film layer etc. which are formed on the said back surface electrode.

  Details will be described below.

Process (1)
In step (1), a thin film containing at least one organic compound having an NF bond is formed on the surface of the substrate.

<Organic compound having NF bond>
The organic compound having an NF bond is known as a fluorinating agent, and the compound represented by the formula (1) is preferable.

(Where

Is the conjugate base of Bronsted acid. )
In equation (1),

Examples of Bronsted acids that produce methanesulfonic acid, butanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, nitrobenzenesulfonic acid, dinitrobenzenesulfonic acid, trinitrobenzenesulfonic acid, trifluoromethanesulfonic acid, trifluoroethanesulfone Acid, perfluorobutanesulfonic acid, perfluorooctanesulfonic acid, perfluoro (2-ethoxyethane) sulfonic acid, perfluoro (4-ethylcyclohexane) sulfonic acid, trichloromethanesulfonic acid, difluoromethanesulfonic acid, trifluoroethanesulfone Acid, fluorosulfonic acid, chlorosulfonic acid, camphorsulfonic acid, bromocamphorsulfonic acid, Δ ⁴ -cholesten-3-one-6-sulfonic acid, 1-hydroxy-p-men Sulfonic acids such as tan-2-sulfonic acid, p-styrenesulfonic acid, β-styrenesulfonic acid, vinylsulfonic acid, perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid; sulfuric acid, phosphoric acid Mineral acids such as nitric acid; halogen acids such as perchloric acid, perbromic acid, periodic acid, chloric acid and bromic acid; monoalkyl sulfuric acids such as monomethyl sulfuric acid and monoethyl sulfuric acid; acetic acid, formic acid, trichloroacetic acid and trifluoroacetic acid , Carboxylic acids such as pentafluoropropionic acid, dichloroacetic acid, and acrylic acid; HAlF ₄ , HBF ₄ , HB ₂ F ₇ , HPF ₆ , HSbF ₄ , HSbF ₆ , HSb ₂ F ₁₁ , HAsF ₆ , HAlCl ₄ F, HAlCl ₃ F _{, HAlF 3 Cl, hBCl 4,} hBCl 3 F, HBBr 3 F, HSbCl 6, HSbCl 5 F , etc. Le of Compounds of acetic acid and hydrogen halide; HBPh ₄ (Ph is phenyl group),

Aryl substituted boron compounds such as: (FSO ₂ ) ₂ NH, (PhSO ₂ ) ₂ NH, (CF ₃ SO ₂ ) ₂ NH, (C ₄ F ₉ SO ₂ ) ₂ NH, CF ₃ SO ₂ NHSO ₂ C ₆ F ₁₃ ,

(FSO ₂ ) ₃ CH, (CF ₃ SO ₂ ) ₃ CH, (PhOSO ₂ ) ₃ CH (Ph is a phenyl group), (CF ₃ SO ₂ ) ₂ CH ₂ , (CF ₃ SO ₂ ) ₃ CH, (C ₄ F ₉ SO ₂ ) ₃ CH, (C ₈ F ₁₇ SO ₂ ) ₃ CH and other carbon acid compounds.

  In order to obtain an organic compound having a highly stable NF bond,

As a conjugated base of Bronsted acid having an acidity stronger than that of acetic acid (pKa: 4.56).

Examples of the conjugate base, for ^{_{example, - BF 4, - PF 6}} , - AsF 6, - SbF 6, - AlF 4, - AlCl 4, - SbCl 6, - SbCl 5 F, - Sb 2 F 11, - B 2 ^{_{F 7, - OClO 3, -}} OSO 2 F, - OSO 2 Cl, - OSO 2 OH, - OSO 2 OCH 3, - OSO 2 CH 3, - OSO 2 CF 3, - OSO 2 CCl 3, - OSO 2 C ^{_{4 F 9, - OSO 2 C}} 6 H 5, - OSO 2 C 6 H 4 CH 3, - OSO 2 C 6 H 4 NO 2, - N (SO 2 CF 3) 2 are particularly preferred. Among them, tetrafluoroborate ^(- BF ₄₎ or perfluoroalkane sulfonate ^{_{(- OSO 2 CF 3, -}} OSO 2 C 4 F 9 , etc.) is preferred.

  Examples of the organic compound having an NF bond satisfying the formula (1) include an N-fluoropyridinium compound (A), an N-fluoroquinuclidinium salt (B), and an N-fluoro-1,4-diazonia. And bicyclo [2.2.2] octane compound (C).

  Preferred compounds as the N-fluoropyridinium compound (A) are those represented by the following formula (A1), (A2) or (A3).

In the formulas (A1) to (A3), adjacent R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ or R ⁴ and R ⁵ are connected to each other, and —CR ⁶ = CR ⁷ —CR ⁸ = CR ⁹ − may be formed, and R ¹ ′ and R ² ′, R ² ′ and R ³ ′, R ³ ′ and R ⁴ ′, or R ⁴ ′ and R ⁵ ′ CR ⁶ ′ = CR ⁷ ′ —CR ⁸ ′ = CR ⁹ ′ — may be formed, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹ ′, R ² ′, R ³ ′, R ⁴ ′, R ⁵ ′, R ⁶ ′, R ⁷ ′, R ⁸ ′ and R ⁹ ′ are the same or different, and all are hydrogen atoms; halogen atoms Nitro group; hydroxy group; cyano group; carbamoyl group; halogen atom, hydroxyl group, alkoxy group having 1 to 5 carbon atoms, aryloxy group having 6 to 10 carbon atoms, acyl group having 1 to 5 carbon atoms, 1 to carbon atoms An alkyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of an acyloxy group and an aryl group having 6 to 10 carbon atoms; a halogen atom and an aryl group having 6 to 10 carbon atoms An alkenyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group; and optionally substituted with at least one selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms An alkynyl group having 1 to 15 carbon atoms; an aryl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms; at least one halogen An acyl group having 1 to 15 carbon atoms which may be substituted with an atom; less selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms May be substituted with one kind of an alkoxycarbonyl group having 2 to 15 carbon atoms; 7 carbon atoms that may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms An aryloxycarbonyl group having 15 to 15 carbon atoms; an alkylsulfonyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms; a halogen atom and a carbon number An arylsulfonyl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of 1 to 5 alkyl groups; at least selected from the group consisting of halogen atoms and aryl groups having 6 to 10 carbon atoms An alkylsulfinyl group having 1 to 15 carbon atoms which may be substituted with one kind; a halogen atom and an alkyl group having 1 to 5 carbon atoms; An arylsulfinyl group having 6 to 15 carbon atoms that may be substituted with at least one selected from the group consisting of: a halogen atom and an aryl group having 6 to 10 carbon atoms that is substituted with at least one selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms An optionally substituted alkoxy group having 1 to 15 carbon atoms; an aryloxy group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms; An acyloxy group having 1 to 15 carbon atoms which may be substituted with one halogen atom; an acylthio group having 1 to 15 carbon atoms which may be substituted with at least one halogen atom; a halogen atom and 6 to 6 carbon atoms An alkanesulfonyloxy group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of 10 aryl groups; An arylsulfonyloxy group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a gen atom and an alkyl group having 1 to 5 carbon atoms; an alkyl group having 1 to 5 carbon atoms and 6 carbon atoms A carbamoyl group optionally substituted with at least one selected from the group consisting of 10 to 10 aryl groups; may be substituted with at least one selected from the group consisting of an acyl group having 1 to 5 carbon atoms and a halogen atom A good amino group; an N-alkylpyridinium having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom, an aryl group having 6 to 10 carbon atoms and an alkyl group having 1 to 5 carbon atoms A base; substituted with at least one selected from the group consisting of a halogen atom, an aryl group having 6 to 10 carbon atoms and an alkyl group having 1 to 5 carbon atoms Good N- aryl pyridinium base of carbon number 11 to 15; a or an organic polymer ^{chain, R 1, R 2, R} 3, R 4, R 5, R 6, R 7, R 8, R 9, R 1 ' , R ² ′, R ³ ′, R ⁴ ′, R ⁵ ′, R ⁶ ′, R ⁷ ′, R ⁸ ′ and R ⁹ ′ form a ring structure in various combinations with or without a heteroatom. In formula (A2), one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ is

(R is a single bond or an alkylene group having 1 to 5 carbon atoms), and in the formula (A3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ One of R ¹ ′, R ² ′, R ³ ′, R ⁴ ′, R ⁵ ′, R ⁶ ′, R ⁷ ′, R ⁸ ′ and R ⁹ ′ with a single bond A chain is formed. Also,

Is the same as equation (1),

Is the same.

  Among the N-fluoropyridinium salts (A) used in the present invention, particularly preferable compounds include the following formula (A1a):

(In the formula, R ^1a , R ^2a , R ^3a , R ^4a and R ^5a are the same or different, and all are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a haloalkyl group having 1 to 4 carbon atoms, a halogen atom, A phenyl group optionally substituted with a methyl group or a halogen, an alkoxy group having 1 to 4 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, or an alkoxycarbonyl group having 2 to 4 carbon atoms Cyano group or nitro group;

Is a conjugate base of Bronsted acid with a pKa of 4.56 or less)
And the compound (A1a) represented by the following formula (A2a):

[Wherein one of R ^1a , R ^2a , R ^3a , R ^4a and R ^5a is

(R is an integer of 0 to 5, preferably 0 to 2), and the others are the same or different, all of which are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a haloalkyl group having 1 to 4 carbon atoms, or a halogen atom. Is]
And an N-fluoropyridinium salt selected from the group consisting of the compound represented by formula (A2a).

  Further, the following formula (A3a):

(Wherein R ^1a , R ^2a , R ^3a , R ^4a , R ^5a , R ^1a ′, R ^2a ′, R ^3a ′, R ^4a ′ and R ^5a ′ are the same or different, and all are hydrogen atoms, carbons An alkyl group having 1 to 4 carbon atoms, a haloalkyl group having 1 to 4 carbon atoms, a halogen atom, a methyl group or a phenyl group optionally substituted with a halogen, an alkoxy group having 1 to 4 carbon atoms, an acyl having 2 to 4 carbon atoms Group, an acyloxy group having 2 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a cyano group or a nitro group, and one of R ^1a , R ^2a , R ^3a , R ^4a and R ^5a is R ^1a. A single bond with one of ', R ^2a ', R ^3a ', R ^4a ', R ^5a 'to form a bond chain;

Is a conjugate base of Bronsted acid having a pKa of 4.56 or less)
The compound (A3a) represented by these is also mentioned.

  As N-fluoroquinuclidinium salt (B), particularly preferred compounds are represented by the following formula (B):

(Where

Is the same as equation (1))
It is shown by.

  Further, particularly preferred compounds as the N-fluoro-1,4-diazoniabicyclo [2.2.2] octane compound (C) are those represented by the formula (C):

(In the formula, Rc is a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, a haloalkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 10 carbon atoms;

Are the same or different and both are the same as in formula (1))
It is shown by.

  Among these organic compounds having an NF bond, the N-fluoropyridinium compound (A) is preferable because it has an aromatic ring skeleton that easily accepts electrons.

  In the present invention, only one type of organic compound having an NF bond may be used, or two or more types may be used in combination. When two or more organic compounds having an NF bond are used in combination, the organic compounds having an NF bond may be arbitrarily combined, and the composition ratio may be adjusted as appropriate.

<Second component in the thin film>
Furthermore, it is also preferably used to improve the function by combining these organic compounds having an NF bond and a compatible second component. For example, by adding an ionic liquid, it is possible to adjust film viscosity, uniformity, ease of application, adhesion such as wettability with a substrate described later, and the like.

  Specific ionic liquids include imidazolium salts, pyridinium salts, and ammonium salts described in reagent catalogs that contain ionic liquids from Aldrich, or reagent catalogs that contain aliphatic ionic liquids from Kanto Chemical Co., Inc. And compounds such as phosphonium salts.

  For example, for the purpose of improving the adhesion in a silicon substrate having a hydrogen termination, a counter cation or counter anion having a long alkyl chain length or a relatively large molecular weight of these ions is preferably used.

  Specific examples include 1-Hexadecyl-3-methylimidazolium chloride, 1-Hexylpylidinium trifluoromethanesulfonate, Trihexyltetradecylphosphonium dicyanamide, and the like.

  Further, as the second component, an organic solvent having high compatibility with an organic compound having an NF bond, a polymer, an oil, or the like may be mixed and used.

  Examples of the organic solvent include acetonitrile, propionitrile, benzonitrile, methyl ethyl ketone, t-butyl methyl ketone, acetone, methyl acetate, ethyl acetate, methyl formate, ethyl formate, diethyl ether, diisopropyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran. , Dioxane, 1,3-dioxolane, dimethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, γ-butyrolactone, γ-valerolactone, Examples include sulfolane and methyl sulfolane.

  In addition, as the polymer, a hydrophilic polymer containing a polar group in the molecule, such as polyvinyl alcohol, polyoxyalkylene, or an ion exchange polymer having compatibility with an organic compound having an NF bond, fluorine-containing polymer Examples thereof include alkyl ether polymers.

  As the oil, animal and vegetable oils such as squalene and fatty acid esters, and synthetic oils such as silicone oil composed of dimethylsiloxane can be used.

<Board>
As a material for the substrate, a semiconductor, an insulator, or the like can be used.

  As the semiconductor, not only a single crystal semiconductor but also a polycrystalline semiconductor, an amorphous semiconductor, and the like can be used. For example, silicon such as single crystal silicon, polycrystalline silicon, and amorphous silicon, silicon carbide (SiC), germanium, Silicon germanium, gallium arsenide, gallium aluminum arsenide, indium gallium arsenide, indium phosphide, indium antimony, copper indium selenium, copper indium gallium selenium, indium tin oxide, cadmium tellurium, cadmium sulfide, zinc oxide, copper aluminum oxide, tin oxide, nitriding Gallium, aluminum nitride, etc. can be used. Examples of the insulator include metal oxides such as zirconium oxide, hafnium oxide, tantalum oxide, aluminum oxide, titanium oxide, and chromium oxide, and silicates thereof, silicon oxide such as silicon dioxide and quartz, silicon nitride, Sapphire can be used.

  Note that these substrates may be ones that have been mirror-polished on the entire surface, or ones that are mirror-polished only on the surface on which a thin film containing an organic compound having an NF bond is formed. .

  The organic compound having an NF bond in a thin film containing at least one organic compound having an NF bond formed on the substrate is preferably a single crystal, a polycrystal, or an amorphous material. The thin film containing at least one organic compound having s is not necessarily solid, and may be partly liquid. In that case, it is preferable that the thin film containing at least one organic compound having an NF bond is uniformly applied to the substrate surface and does not easily flow out even if the coating surface is not kept horizontal. As a result, transportation becomes easy, it becomes possible to perform etching by setting the application surface of the substrate in various directions, and it is also possible to etch the entire surface of the substrate. Note that the applied organic compound having an NF bond is preferably amorphous so that the irradiated light is not diffusely reflected.

  The thickness of the substrate is not particularly limited, but is preferably about 500 nm to 1000 μm. Note that there is an optimum value for the thickness of the substrate depending on the material and the type of solar cell, which is about 300 μm to 1000 μm for single crystal materials, 150 μm to 300 μm for polycrystalline materials, and about 500 nm to 50 μm for amorphous materials.

<Method for forming a thin film containing at least one organic compound having an NF bond on a substrate>
As a method for forming a thin film containing at least one organic compound having an NF bond on the surface of a substrate, specifically,
(1A) A method of dissolving an organic compound having an N—F bond in a solvent, applying the organic compound to the surface of the substrate, and removing the solvent can be mentioned.

Note that when the organic compound having an NF bond is liquid or can be liquefied by heating or the like, the liquefied one can be applied to the surface of the substrate. In that case, as a method for forming a thin film containing at least one organic compound having an NF bond on the surface of the substrate,
(1B) A method in which an organic compound having an NF bond is liquefied and applied to the surface of the substrate is also exemplified.

  When employing the method (1A) as the step (1), the solvent for dissolving the organic compound having an NF bond is not particularly limited, but examples thereof include acetonitrile, propionitrile, benzonitrile, Methyl ethyl ketone, t-butyl methyl ketone, acetone, methyl acetate, ethyl acetate, methyl formate, ethyl formate, diethyl ether, diisopropyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, dimethoxyethane, diethylene glycol dimethyl ether, tri Ethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, γ-butyrolactone, γ-valerolactone , Sulfolane, methyl sulfolane and the like. Of these, acetonitrile, acetone, tetrahydrofuran, and dimethoxyethane are preferred because the solubility of the organic compound having an NF bond is high.

  A method for applying a solvent in which an organic compound having an NF bond is dissolved or a liquefied organic compound having an NF bond to a substrate is not particularly limited. For example, a spin coating method is used. It can be applied by a dipping method, a spray method, an ink jet method or a doctor blade method.

  In that case, you may apply | coat to the whole surface of a board | substrate, and may apply only partially. In addition, when applying partially, the method of spraying with a mask and the method of apply | coating by the inkjet method are preferable. Further, a mask may be formed after an organic compound having an NF bond is applied to the entire surface. The material for masking is not particularly limited as long as it can be shielded from light when the substrate is irradiated with light, such as metal materials such as Si, Cu, SUS (stainless steel), ceramics, etc. Inorganic materials or organic materials such as organic polymers can also be used. The shape of the mask is not particularly limited, and may be set according to the shape of the substrate to be finally obtained. A photomask having a predetermined width may be used, or a fine metal mesh may be used. A complicated shape may be used. In addition, when applying droplets using inkjet, the size of the applied droplets determines the resolution of the etching shape. Here, the size of the droplet that can be applied depends on the shape of the inkjet head and the viscosity of the liquid to be ejected, and the smaller the viscosity, the smaller the droplet that can be applied. Accordingly, in order to apply an organic compound having an N—F bond to a substrate in a desired size, when applying droplets by an inkjet method, temperature control is performed on the inkjet head to control the temperature of the inkjet head. It is desirable to control the viscosity of the organic compound having an NF bond so as to facilitate the control of the spot size during coating.

  The film thickness when applying the organic compound having an NF bond is not particularly limited, but if it is thin, the effect of etching the substrate is not seen, and if it is thick, the light irradiated in step (2) described later is dispersed. From the viewpoint of difficulty in fine processing, 100 nm to 500 μm is preferable, and 200 nm to 100 μm is more preferable. In addition, when etching deeply, it is preferable to apply thickly.

  In the method (1A), the method for removing the solvent is not particularly limited, but for example, a method of removing by heat treatment at 0.1 kPa to 0.1 MPa, 25 to 100 ° C., or room temperature (25 ° C. Degree) and a method of blowing air under normal pressure (about 0.1 MPa).

  When the method (1B) is employed as the step (1), when the organic compound having an NF bond can be liquefied by heating, the heat treatment is preferably 0 to 150 ° C., although it depends on the melting point, the freezing point, and the like. . In addition, the melting point is lowered by mixing another compound having compatibility with an organic compound having an NF bond having a different structure or an organic compound having an NF bond such as an ionic liquid, an organic acid salt, or an amine salt, Liquefaction is also preferably used.

  Here, if a specific example is given, organic compound (I) which has NF bond: N-fluoro-3-methylpyridinium tetrafluoroborate (melting point 59 degreeC) and organic compound (IV) which has NF bond When N: fluoro-4-methylpyridinium tetrafluoroborate (melting point 66 ° C.) is mixed 2: 1, the melting point is lowered to −17 ° C. Therefore, when the thin film is used as a solid, (I) and (IV) are each used alone, and when used as a liquid, an organic compound having at least two kinds of NF bonds is mixed. Can be used.

  When a thin film containing at least one organic compound having an NF bond is formed on the substrate by the above method, if the thin film contains a liquid or liquid material, it may be dried thereafter. What is necessary is just to adjust drying conditions suitably with the organic compound which has a NF bond to be used. Alternatively, an organic compound having an NF bond may be liquefied by heating and applied, and then solidified by cooling. In this case, the heating may be at or above the melting point of the organic compound having an NF bond, and the cooling temperature may be at or below the freezing point.

Step (2)
Next, in step (2), the substrate is exposed from the side of the organic compound having an NF bond.

  Examples of the exposure method include a method of irradiating visible light, ultraviolet rays, infrared rays, X-rays, electron beams, ion beams and the like. At this time, the entire surface coated with the organic compound having an NF bond may be irradiated. However, in the case of partial irradiation, a masking method can be used, but a projector or the like can be used easily. A desired location can be irradiated. Among these lights, visible light or ultraviolet light is preferable. In addition, when X-rays are used, the spatial resolution can be improved.

  Here, visible light has a wavelength of about 400 to 800 nm, ultraviolet light has a wavelength of about 10 to 400 nm, infrared light has a wavelength of about 800 nm to 25 μm, X-ray has a wavelength of about 0.01 to 70 nm, and electron beam has an acceleration. The voltage is about 0.1 kV to 200 kV, and the ion beam means an acceleration voltage of about 1 kV to 200 kV. The laser beam is excellent in that the light irradiation range can be controlled accurately and easily, and can be used regardless of the pulse width, output, wavelength, oscillation method and medium.

Exposure intensity is, 0.001~100W / mm ^2, further preferably 0.01 to 10 / mm ^2. The exposure time is preferably 1 second to 24 hours, more preferably 10 seconds to 5 hours. Further, exposure amount, 0.001~100W · h / mm ^2, further preferably 0.01~10W · h / mm ^2.

  By exposing in the step (2), the irradiated portion of the substrate can be directly etched without developing the applied organic compound having an NF bond. Although this principle is not necessarily clear, the substrate activated by exposure and an organic compound having an NF bond undergo some kind of reaction and are etched (electron excitation occurs from the solid material due to light irradiation, resulting in N- It reacts with an organic compound having an F bond, and the active species generated here react with the solid material to cause etching to proceed).

  Considering the above mechanism, the etching rate can be improved by placing the substrate-derived fluoride in a state where it can be easily removed. Specifically, the etching rate can be improved by etching under heating, etching under reduced pressure, or a combination thereof.

  Furthermore, it is also preferable to perform the second processing operation before the step (3) of removing the thin film containing an organic compound having an NF bond from the substrate. According to this continuous etching operation, a complicated shape can be processed in one step. The advantages of the substrate processing process obtained here cannot be achieved by ordinary etching operations. Furthermore, by adjusting the light irradiation intensity in steps, it is possible to process a substrate having a texture structure with a complicated structure. Specifically, slopes, phase structures, etc. can be created.

  In addition to the above-described continuous etching, a substrate having a texture structure with a complicated shape can be created by adding gradation to the light intensity during exposure. For example, when the projector is used, this gradation can change the intensity of light emitted for each grid of about 10 μm × 10 μm.

Process (3)
As described above, after etching the solid material by the steps (1) and (2),
(3) For a solar cell having at least one surface roughened and having a desired shape by removing a thin film containing at least one organic compound having an NF bond together with a residue between the thin film and the substrate. A substrate is obtained.

  At this time, a specific method for removing the thin film containing at least one organic compound having an NF bond is not particularly limited. For example, acetonitrile, propionitrile, benzonitrile, methyl ethyl ketone, t -Butyl methyl ketone, acetone, methyl acetate, ethyl acetate, methyl formate, ethyl formate, diethyl ether, diisopropyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, dimethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether , Tetraethylene glycol dimethyl ether, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, γ-butyrolactone, γ-valerolactone, sulfo Examples thereof include a method of immersing in an organic solvent such as run and methylsulfolane, and a method of spraying the organic solvent while rotating.

  In addition, after removing the thin film containing at least one organic compound having an N—F bond, the substrate is immersed in the organic solvent again, and subjected to stirring, ultrasonic irradiation, or the like as necessary, to thereby obtain a substrate such as a silicon substrate. The residue adhering to the top can be removed more reliably.

  As described above, the solar cell substrate of the present invention is etched from various directions without using high environmental loads that cause global warming, or reactive, toxic and dangerous fluorine gas or hydrofluoric acid. Therefore, it is possible to easily and safely manufacture an etching processed product having a more complicated shape with the same apparatus configuration.

  The solar cell substrate of the present invention thus obtained has a width of several tens of nanometers to several tens of μm on the surface, and the depth is several nanometers to several nanometers, although the thickness of the substrate differs depending on the material. It has irregularities of about μm. As a result, the reflectance of incident sunlight is reduced from that of the untreated one, and the antireflection effect can be achieved by several tens of percent, although it depends on the wavelength of the incident light. By achieving this antireflection effect, the energy conversion efficiency as a solar cell is improved by about several percent to 10% as compared with an untreated one.

  Hereinafter, embodiments of the solar cell substrate of the present invention will be specifically described with reference to the drawings. In the following, in order to simplify the description, a case where a silicon substrate is used as the substrate and an N-fluoropyridinium salt is used as the organic compound having an NF bond will be described.

First Embodiment FIG. 1 is a schematic cross-sectional view showing a step of selectively etching a silicon substrate in a first embodiment of the present invention to obtain a solar cell substrate having a desired shape.

  First, as shown in FIG. 1A, an N-fluoropyridinium salt 3 is applied on a silicon substrate 4, and then a photomask 2 attached to the photomask substrate 1 is laminated. At this time, a photomask having a complicated shape such as a fine metal mesh can be used as the photomask, whereby a substrate having a complicated shape can be formed. When a fine metal mesh is used, the mesh diameter, pitch diameter, thickness, etc. are not particularly limited, and may be set as appropriate according to the shape of the substrate to be obtained.

  Thereafter, exposure through the photomask 2 causes a chemical reaction at the interface between the N-fluoropyridinium salt 3 and the silicon substrate 4 as shown in FIG. 1B, whereby the silicon substrate 4 can be selectively etched. Although FIG. 1 shows the case where light having the same intensity is irradiated, a substrate having a complicated shape can be formed by adding gradation to the intensity of light irradiation.

  Then, as shown in FIG.1 (c), the board | substrate for solar cells which has the etching trace 6 of a desired shape is obtained by removing the layer of N-fluoro pyridinium salt 3. FIG.

Second Embodiment FIG. 2 is a schematic cross-sectional view showing a step of selectively etching a silicon substrate in a second embodiment of the present invention to obtain a solar cell substrate having a desired shape.

  Note that the difference from the first embodiment is that the photomask 2 is directly laminated on the layer of the N-fluoropyridinium salt 3, and the other portions are the same.

  First, as shown in FIG. 2A, an N-fluoropyridinium salt 3 is applied on a silicon substrate 4, and then a photomask 2 is laminated. At this time, a photomask having a complicated shape such as a fine metal mesh can be used as the photomask, whereby a substrate having a complicated shape can be formed. When a fine metal mesh is used, the mesh diameter, pitch diameter, thickness, etc. are not particularly limited, and may be set as appropriate according to the shape of the substrate to be obtained.

  Thereafter, by exposing through the photomask 2, a chemical reaction occurs at the interface between the N-fluoropyridinium salt 3 and the silicon substrate 4 as shown in FIG. 2B, and the silicon substrate 4 can be selectively etched. Note that FIG. 2 shows a case where light having the same intensity is irradiated, but a substrate having a complicated shape can be formed by adding gradation to the intensity of light irradiation.

  Then, as shown in FIG.2 (c), the board | substrate for solar cells which has the etching trace 6 of a desired shape is obtained by removing the layer of N-fluoro pyridinium salt 3. As shown in FIG.

Third Embodiment FIG. 3 is a schematic cross-sectional view showing a step of obtaining a solar cell substrate having a desired shape by selectively etching a silicon substrate in a third embodiment of the present invention.

  Note that the difference from the first embodiment and the second embodiment is that the photomask 2 is not laminated and is selectively exposed at a desired location, and the other locations are the same.

  First, as shown in FIG. 3A, an N-fluoropyridinium salt 3 is applied on a silicon substrate 4 and then selectively exposed using a projector or the like.

  As a result, as shown in FIG. 3B, a chemical reaction occurs at the interface between the N-fluoropyridinium salt 3 and the silicon substrate 4, and the silicon substrate 4 can be selectively etched. Although FIG. 3 shows a case where light having the same intensity is irradiated, a substrate having a complicated shape can be formed by adding gradation to the intensity of light irradiation.

  Then, as shown in FIG.3 (c), the board | substrate for solar cells which has the etching trace 6 of a desired shape is obtained by removing the layer of N-fluoro pyridinium salt 3. As shown in FIG.

Fourth Embodiment FIG. 4 is a schematic sectional view showing a step of obtaining a solar cell substrate having a desired shape by selectively etching a silicon substrate in a fourth embodiment of the present invention.

  Note that the difference from the first embodiment, the second embodiment, and the third embodiment is that the photomask 2 is not laminated or selectively exposed to a desired location without being laminated. The N-fluoropyridinium salt 3 is applied by inkjet or the like, and other portions are the same. At this time, the N-fluoropyridinium salt to be applied does not need to be a thin film, and droplets made of the N-fluoropyridinium salt may be applied.

  First, as shown in FIG. 4A, the N-fluoropyridinium salt 3 is applied to a desired location on the silicon substrate 4.

  Thereafter, by exposure, a chemical reaction occurs at the interface between the N-fluoropyridinium salt 3 and the silicon substrate 4 as shown in FIG. 4B, and the silicon substrate 4 can be selectively etched. Although FIG. 4 shows a case where only one place is irradiated, a substrate having a complicated shape can be formed by forming the N-fluoropyridinium salt 3 at a desired place.

  Then, as shown in FIG.4 (c), the board | substrate for solar cells which has the etching trace 6 of a desired shape is obtained by removing the layer of N-fluoro pyridinium salt 3. As shown in FIG.

2. Solar Cell The solar cell of the present invention includes the above-described solar cell substrate, and the production method thereof is not particularly limited and can be produced by a known method. For example, the solar cell of this invention can be manufactured with the aspect shown below.

First Embodiment First, the solar cell substrate of the present invention is used as a back electrode. Next, a semiconductor material is formed on the uneven surface of the back electrode by a vapor deposition method, a vapor phase growth method, or the like to constitute a solar cell. In an ordinary solar cell, an antireflection film is further formed on a semiconductor material. However, in the present invention, an antireflection film may or may not be formed. This method is an effective form in the production of a solar cell using polycrystalline silicon, microcrystalline silicon, amorphous silicon, or a compound semiconductor, in which a semiconductor material is formed by vapor deposition, vapor deposition, or the like.

  Here, an insulating material or an electrode material can be used as the material of the solar cell substrate as the back electrode. As the insulating material, metal oxides such as zirconium oxide, hafnium oxide, tantalum oxide, aluminum oxide, titanium oxide, and chromium oxide, and silicon oxides such as silicate, silicon dioxide, and quartz, silicon nitride, sapphire, and the like should be used. In particular, silicon oxide is preferably used, and various semiconductor materials can be used as the electrode material. However, tin oxide, zinc oxide, indium tin oxide, and the like are preferable in terms of transparency.

  Examples of the semiconductor material include silicon such as single crystal silicon, polycrystalline silicon, and amorphous silicon, silicon carbide (SiC), germanium, silicon germanium, gallium arsenide, gallium aluminum arsenide, indium gallium arsenide, indium phosphide, and indium. Antimony, copper indium selenium, copper indium gallium selenium, indium tin oxide, cadmium tellurium, cadmium sulfide, zinc oxide, copper aluminum oxide, tin oxide, gallium nitride, aluminum nitride, or the like can be used. Examples of the insulator include metal oxides such as zirconium oxide, hafnium oxide, tantalum oxide, aluminum oxide, titanium oxide, and chromium oxide, and silicates thereof, silicon oxide such as silicon dioxide and quartz, silicon nitride, Sapphire can be used.

Second Embodiment First, an insulating material or an electrode material is used as the back electrode, and the solar cell substrate of the present invention made of a semiconductor material is formed on the back electrode. When the solar cell substrate of the present invention is formed on the back electrode, a semiconductor material is first formed on the back electrode by vapor deposition, vapor phase growth, or the like. Then, a solar cell can be comprised by etching a semiconductor material by the method similar to the method of obtaining the board | substrate for solar cells of this invention. In an ordinary solar cell, an antireflection film is further formed on a semiconductor material. However, in the present invention, an antireflection film may or may not be formed.

  In addition, as an insulating material, an electrode material, and a semiconductor material, the thing similar to what was demonstrated by said 1st form can be used.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited only to these.

  In the following examples, the following were used as the organic compound having an NF bond, the substrate, and the irradiation light source.

<Organic compound having NF bond>
Organic compound (I) having NF bond: N-fluoro-3-methylpyridinium tetrafluoroborate

  Organic compound (II) having NF bond: N-fluoro-4-methylpyridinium tetrafluoroborate

<Solid material>
Single crystal silicon substrate: produced by CZ method (dopant: B, p-type, plane orientation (100), resistivity: 8-25 Ωcm, thickness 550 μm)
Polycrystalline silicon substrate: produced in Example 3 Amorphous silicon substrate: produced in Example 4 <Irradiation Light Source>
Xenon lamp: manufactured by Hamamatsu Photonics Co., Ltd., high stability xenon lamp L2274 type 3LCD projector: manufactured by EPSON, EMP-1825 type (lamp output: 275 W, maximum brightness: 1200 lumen)

Example 1: Inkjet <Step A: Pretreatment of substrate>
A 2 cm square silicon substrate was washed with ultrapure water for 3 minutes and treated with 97% sulfuric acid and 30% hydrogen peroxide solution (sulfuric acid: hydrogen peroxide solution = 4: 1 (volume ratio)) for 10 minutes on the silicon substrate. The organic matter was removed. This was washed with ultrapure water for 10 minutes and then treated with dilute hydrofluoric acid for 1 minute to remove the surface oxide film. Furthermore, it was treated with 97% sulfuric acid and 30% hydrogen peroxide (sulfuric acid: hydrogen peroxide = 4: 1 (volume ratio)) for 10 minutes to make the surface hydrophilic, and finally washed with ultrapure water for 10 minutes. .

<Step B: Application of organic compound having NF bond>
A single crystal silicon substrate obtained by melting a mixture (weight ratio 2: 1) of an organic compound (I) having an NF bond and an organic compound (II) having an NF bond (2: 1 by weight), pretreating and drying in step A The desired portion was coated by an ink jet method.

<Process C: Light irradiation>
The single crystal silicon substrate coated with the organic compound having an N—F bond in Step B was irradiated with light containing wavelengths in the ultraviolet to infrared region for 60 minutes by a xenon lamp (exposure wavelength 220 to 2000 nm, exposure intensity 700 mW / cm). ² ).

<Step D: Removal of thin film containing organic compound having NF bond>
The thin film containing an organic compound having an NF bond on the surface of the single crystal silicon substrate was immersed in acetonitrile and removed by ultrasonic cleaning for 20 seconds. Further, the remaining residue was soaked in acetone and removed by ultrasonic irradiation for 20 seconds.

<Evaluation>
The surface of the obtained substrate was observed with a phase shift interference microscope (manufactured by ZYGO, NewView). The results are shown in FIG. From FIG. 5, it can be confirmed that only the portion where the organic compound having an NF bond is applied is etched.

Example 2: Control of light intensity <Step A: Pretreatment of substrate>
A 2 cm square silicon substrate was washed with ultrapure water for 3 minutes and treated with 97% sulfuric acid and 30% hydrogen peroxide solution (sulfuric acid: hydrogen peroxide solution = 4: 1 (volume ratio)) for 10 minutes on the silicon substrate. The organic matter was removed. This was washed with ultrapure water for 10 minutes and then treated with dilute hydrofluoric acid for 1 minute to remove the surface oxide film. Furthermore, it was treated with 97% sulfuric acid and 30% hydrogen peroxide (sulfuric acid: hydrogen peroxide = 4: 1 (volume ratio)) for 10 minutes to make the surface hydrophilic, and finally washed with ultrapure water for 10 minutes. .

<Step B: Application of organic compound having NF bond>
A single crystal silicon substrate obtained by melting a mixture (weight ratio 2: 1) of an organic compound (I) having an NF bond and an organic compound (II) having an NF bond (2: 1 by weight), pretreating and drying in step A It was applied to the entire surface of

<Process C: Light irradiation>
The single crystal silicon substrate coated with the organic compound having an NF bond in Step B was irradiated with visible light by a 3LCD projector for 240 minutes (exposure wavelength 450 to 700 nm, exposure intensity 0 to 0). 76 mW / cm ² ).

<Step D: Removal of thin film containing organic compound having NF bond>
The thin film containing an organic compound having an NF bond on the surface of the single crystal silicon substrate was immersed in acetonitrile and removed by ultrasonic cleaning for 20 seconds. Further, the remaining residue was soaked in acetone and removed by ultrasonic irradiation for 20 seconds.

<Evaluation>
The surface of the obtained substrate was observed with a phase shift interference microscope (manufactured by ZYGO, NewView). The results are shown in FIG. It can be seen from FIG. 6 that the silicon surface can be etched in a desired shape without using a mask.

Example 3: Polycrystalline silicon substrate <Preparation of polycrystalline silicon substrate>
SiO ₂ was deposited by thermal CVD with a film thickness of about 60 nm on an undoped single crystal silicon substrate. The sample size was 2 cm square.

  The obtained substrate was measured by 200 keV electron diffraction, and confirmed to be a polycrystalline silicon substrate.

<Process A: Pretreatment of substrate>
The polycrystalline silicon substrate produced as described above was impregnated in acetone, subjected to ultrasonic cleaning for 5 minutes, then with ultrapure water for 5 minutes, and further treated with UV ozone for 10 minutes to make the surface hydrophilic. .

<Step B: Application of organic compound having NF bond>
A polycrystalline silicon substrate obtained by melting a mixture (weight ratio 2: 1) of an organic compound (I) having an NF bond and an organic compound (II) having an NF bond, pretreated in step A and dried. In addition, a spot-like film having a diameter of 5 mmφ was applied by an inkjet method.

<Process C: Light irradiation>
The polycrystalline silicon substrate coated with the organic compound having an NF bond in step B was irradiated with light containing wavelengths in the ultraviolet to infrared region for 30 minutes by a xenon lamp (exposure wavelength 220 to 2000 nm, exposure intensity 1000 mW / cm). ² ).

<Step D: Removal of thin film containing organic compound having NF bond>
The thin film containing an organic compound having an NF bond on the surface of the polycrystalline silicon substrate was immersed in acetonitrile and removed by ultrasonic cleaning for 20 seconds. Further, the remaining residue was soaked in acetone and removed by ultrasonic irradiation for 20 seconds.

<Evaluation>
The surface of the obtained substrate was observed with a phase shift interference microscope (manufactured by ZYGO, NewView). The results are shown in FIG. From FIG. 7, even when a polycrystalline material is used as the substrate, it can be confirmed that only a portion where an organic compound having an NF bond is applied is etched.

Example 4: Amorphous silicon substrate <Preparation of amorphous silicon substrate>
On a single crystal silicon substrate without doping, SiO ₂ was deposited by thermal CVD with a film thickness of about 20 nm. The sample size was 2 cm square.

  The obtained substrate was measured by 200 keV electron diffraction, and confirmed to be an amorphous silicon substrate.

<Process A: Pretreatment of substrate>
The amorphous silicon substrate produced as described above was washed with ultrapure water for 5 minutes and further treated with UV ozone for 10 minutes to make the surface hydrophilic.

<Step B: Application of organic compound having NF bond>
A mixture of an organic compound (I) having an NF bond and an organic compound (II) having an NF bond (weight ratio 2: 1) is melted, pretreated in step A, and dried. It was applied to the entire surface.

<Process C: Light irradiation>
A 2 mm wide silicon piece was placed as a mask on the amorphous silicon substrate coated with an organic compound having an NF bond in Step B, and irradiated with light containing wavelengths in the ultraviolet to infrared region for 30 minutes (exposure wavelength). 220 to 2000 nm, exposure intensity 1000 mW / cm ² ).

<Step D: Removal of thin film containing organic compound having NF bond>
A thin film containing an organic compound having an NF bond on the surface of the amorphous silicon substrate was immersed in acetonitrile and removed by ultrasonic cleaning for 20 seconds. Further, the remaining residue was soaked in acetone and removed by ultrasonic irradiation for 20 seconds.

<Evaluation>
The surface of the obtained substrate was observed with a phase shift interference microscope (manufactured by ZYGO, NewView). The results are shown in FIG. From FIG. 8, even when an amorphous material is used as the substrate, it can be confirmed that only a portion irradiated with light without a mask is etched.

Example 5: Mesh mask (TEM mesh grid mesh—80 μm pitch, hole width 50 μm, mesh diameter 2.05 mm, thickness 25 μm, bar width 30 μm, material: copper)
A mixture of an organic compound (I) having an NF bond and an organic compound (II) having an NF bond with the same composition was applied to the entire surface of a silicon substrate pretreated in the same manner as in Example 2. . A grid mesh for a TEM electron microscope (80 μm pitch, hole width 50 μm, mesh diameter 2.05 mm, thickness 25 μm, bar width 30 μm, material: copper) is placed on the upper surface of this sample, and an ultraviolet to infrared region by a xenon lamp. For 60 minutes (exposure wavelength 220-2000 nm, exposure intensity 1000 mW / cm ² ).

  The surface of the obtained substrate was observed with a phase shift interference microscope (manufactured by ZYGO, NewView). The results are shown in FIG. From FIG. 9, it can be seen that the shape of the mesh used as a mask is traced with high accuracy, and irregularities are formed with a resolution of about 50 μm.

Example 6: Mesh mask (TEM mesh for TEM electron microscope-12.5 µ pitch, hole width 7.5 µm, mesh diameter 2.05 mm, thickness 4-7 µm, bar width 5 µm, material: copper))
<Process A: Pretreatment of substrate>
After treating a 2 cm square single crystal silicon substrate (dopant: B, p-type, plane orientation (100), resistivity: 10.0-20.0 Ωcm, thickness 600 ± 25 μm) with UV ozone for 10 minutes, ultrapure Rinse with water for 3 minutes. Next, this was treated with dilute hydrofluoric acid for 1 minute, rinsed with ultrapure water for 10 minutes, and further treated with UV ozone for 10 minutes to make the surface hydrophilic.

<Step B: Application of organic compound having NF bond>
A single crystal silicon substrate obtained by melting a mixture (weight ratio 2: 1) of an organic compound (I) having an NF bond and an organic compound (II) having an NF bond (2: 1 by weight), pretreating and drying in step A It was applied to the entire surface of

<Process C: Light irradiation>
A grid mesh for a TEM electron microscope (material is copper; mesh diameter 2.05 mm; 12.5 μm pitch; thickness 4 to 7 μm) is placed on the upper surface of this sample, and light containing wavelengths in the ultraviolet to infrared region is emitted by a xenon lamp. For 30 minutes (exposure wavelength 220 to 2000 nm, exposure intensity 500 mW / cm ² ).

<Step D: Removal of thin film containing organic compound having NF bond>
The thin film containing an organic compound having an NF bond on the surface of the single crystal silicon substrate was immersed in acetonitrile and removed by ultrasonic cleaning for 5 minutes. Further, the remaining residue was immersed in acetone and removed by ultrasonic irradiation for 5 minutes.

<Evaluation>
1) Surface observation The surface of the obtained substrate was observed with a phase shift interference microscope (manufactured by ZYGO, NewView). The results are shown in FIG.

2) Laser used for reflectance measurement: AlGaInP high-power laser diode (manufactured by Opnext, HL65545MG type), peak wavelength: 660 nm
Detector: Optical power / energy meter (Newport, 1918-C type), detector (detector) is Newport, 918D-UV-OD3 type The above laser was used as a light source in the experimental system shown in FIG. The light reflectance of the silicon surface obtained by steps A to D was measured. Further, the light reflectance on the surface of an untreated silicon substrate (used in Example 6) was also measured, and the change in the light reflectance before and after the treatment was evaluated.

  As a result, the light reflectance of the surface of the untreated silicon substrate was 101 to 102 μW, whereas the light reflectance of the surface of the silicon substrate subjected to the processes A to D in Example 6 was 82 to 83 μW. there were.

  From the above, the light reflectance of the silicon surface was reduced by 20% by roughening the substrate using an organic compound having an NF bond.

Example 7: Inkjet <Step A: Pretreatment of Substrate>
A 2 cm square single crystal silicon substrate was treated with UV ozone for 10 minutes, and then rinsed with ultrapure water for 3 minutes. Next, this was treated with dilute hydrofluoric acid for 1 minute, and then rinsed with ultrapure water for 10 minutes.

<Step B: Application of organic compound having NF bond>
A mixture of organic compound (I) having an NF bond and organic compound (II) having an NF bond (weight ratio 2: 1) was melted, and a patterning apparatus (FemtoJet-1000) manufactured by Microjet Co., Ltd. Was applied in a dot pattern on a single crystal silicon substrate pretreated and dried in step A (dot diameter 15 μm, pitch 50 μm).
FemtoJet-1000 operating conditions:
Nozzle head (electrostatic type: nozzle diameter 15 μm)
Nozzle head-silicon substrate distance 30 μm
Drive voltage 600V
Pulse width 20ms

<Process C: Light irradiation>
The single crystal silicon substrate coated with the organic compound having an N—F bond in Step B was irradiated with light containing a wavelength in the ultraviolet to infrared region for 60 minutes by a xenon lamp (exposure wavelength 220 to 2000 nm, exposure intensity 3000 mW / cm). ² ).

<Step D: Removal of thin film containing organic compound having NF bond>
The thin film containing an organic compound having an NF bond on the surface of the single crystal silicon substrate was immersed in acetonitrile and removed by ultrasonic cleaning for 20 seconds. Further, the remaining residue was soaked in acetone and removed by ultrasonic irradiation for 20 seconds.

<Evaluation>
The surface of the obtained substrate was observed with a phase shift interference microscope (manufactured by ZYGO, NewView). The results are shown in FIG. From FIG. 12, it can confirm that only the place which apply | coated the organic compound which has a NF bond is etched. Moreover, it turns out that a fine etching pattern can be formed by controlling the application | coating location finely with an inkjet.

DESCRIPTION OF SYMBOLS 1 Photomask substrate 2 Photomask 3 N-fluoro pyridinium salt 4 Silicon substrate 5 Chemical reaction part 6 Etching process trace 7 Selective exposure

Claims (21)

A substrate in which a thin film containing at least one organic compound having an N—F bond is formed on at least one side of the whole or a part thereof is obtained, and then the thin film is removed together with a residue between the thin film and the substrate. A solar cell substrate having at least one surface roughened. The solar cell substrate according to claim 1, wherein the organic compound having an NF bond has a structural unit represented by the formula (1).

(Where

Is the conjugate base of Bronsted acid. ) The solar cell substrate according to claim 1 or 2, wherein the organic compound having an NF bond is represented by the formula (A1), (A2), or (A3).

[In formulas (A1) to (A3), adjacent R ¹ and R ² , R ² and R ³ , R ³ and R ^4, or R ⁴ and R ⁵ are linked, and —CR ⁶ = CR ⁷ -CR ⁸ ═CR ⁹ —, and R ¹ ′ and R ² ′, R ² ′ and R ³ ′, R ³ ′ and R ⁴ ′ or R ⁴ ′ and R ⁵ ′ are linked, ^{-CR 6 '= CR 7' -CR} 8 '= CR 9' - may be in the ^{form, R 1, R 2, R} 3, R 4, R 5, R 6, R 7, R 8, R ⁹ , R ¹ ′, R ² ′, R ³ ′, R ⁴ ′, R ⁵ ′, R ⁶ ′, R ⁷ ′, R ⁸ ′ and R ⁹ ′ are the same or different and all are hydrogen atoms; halogen Nitro group; hydroxy group; cyano group; carbamoyl group; halogen atom, hydroxyl group, alkoxy group having 1 to 5 carbon atoms, aryloxy group having 6 to 10 carbon atoms, acyl group having 1 to 5 carbon atoms, 1 carbon atom An alkyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of an acyloxy group having 5 and an aryl group having 6 to 10 carbon atoms; a halogen atom and an aryl group having 6 to 10 carbon atoms An alkenyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of: a group having at least one selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms A good alkynyl group having 1 to 15 carbon atoms; an aryl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms; at least one kind An acyl group having 1 to 15 carbon atoms which may be substituted with a halogen atom; a small amount selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms Or an optionally substituted alkoxycarbonyl group having 2 to 15 carbon atoms; a carbon atom having 7 carbon atoms that may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms. An aryloxycarbonyl group having 15 to 15 carbon atoms; an alkylsulfonyl group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an aryl group having 6 to 10 carbon atoms; a halogen atom and a carbon number An arylsulfonyl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of 1 to 5 alkyl groups; at least selected from the group consisting of halogen atoms and aryl groups having 6 to 10 carbon atoms C1-C15 alkyl sulfinyl group which may be substituted by 1 type; A halogen atom and a C1-C5 alkyl group An arylsulfinyl group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of: a halogen atom and at least one selected from the group consisting of aryl groups having 6 to 10 carbon atoms An optionally substituted alkoxy group having 1 to 15 carbon atoms; an aryloxy group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom and an alkyl group having 1 to 5 carbon atoms; An acyloxy group having 1 to 15 carbon atoms which may be substituted with one halogen atom; an acylthio group having 1 to 15 carbon atoms which may be substituted with at least one halogen atom; a halogen atom and 6 to 6 carbon atoms An alkanesulfonyloxy group having 1 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of 10 aryl groups; Arylsulfonyloxy group having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a rogen atom and an alkyl group having 1 to 5 carbon atoms; an alkyl group having 1 to 5 carbon atoms and 6 carbon atoms A carbamoyl group optionally substituted with at least one selected from the group consisting of 10 to 10 aryl groups; may be substituted with at least one selected from the group consisting of an acyl group having 1 to 5 carbon atoms and a halogen atom A good amino group; an N-alkylpyridinium having 6 to 15 carbon atoms which may be substituted with at least one selected from the group consisting of a halogen atom, an aryl group having 6 to 10 carbon atoms and an alkyl group having 1 to 5 carbon atoms A base; substituted with at least one selected from the group consisting of a halogen atom, an aryl group having 6 to 10 carbon atoms and an alkyl group having 1 to 5 carbon atoms Which may N- aryl pyridinium base of carbon number 11 to 15; a or an organic polymer ^{chain, R 1, R 2, R} 3, R 4, R 5, R 6, R 7, R 8, R 9, R 1 ', R ² ', R ³ ', R ⁴ ', R ⁵ ', R ⁶ ', R ⁷ ', R ⁸ ' and R ⁹ 'can be combined in various combinations with or without a heteroatom. In formula (A2), one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ is

(R is a single bond or an alkylene group having 1 to 5 carbon atoms), and in the formula (A3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ One of R ¹ ′, R ² ′, R ³ ′, R ⁴ ′, R ⁵ ′, R ⁶ ′, R ⁷ ′, R ⁸ ′ and R ⁹ ′ with a single bond A chain is formed. Also,

Is the conjugate base of Bronsted acid. ] ^4. The solar cell according to claim 3, wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ are the same or different in formula (A1), and each is a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. substrate. In formulas (A1) and (A3),

The substrate for solar cells according to claim 3 or 4, wherein is a perfluoroalkanesulfonate. In formulas (A1) and (A3),

The solar cell substrate according to claim 3 or 4, wherein is a tetrafluoroborate. The solar cell substrate according to any one of claims 1 to 6, wherein the thin film containing at least one organic compound having an NF bond further contains at least one ionic liquid. The substrate for a solar cell according to any one of claims 1 to 7, wherein the substrate is a semiconductor or an insulator. The solar cell substrate according to claim 8, wherein the semiconductor is a polycrystalline semiconductor or an amorphous semiconductor. Semiconductors are single crystal silicon, polycrystalline silicon, amorphous silicon, silicon carbide (SiC), germanium, silicon germanium, gallium arsenide, gallium aluminum arsenide, indium gallium arsenide, indium phosphide, indium antimony, copper indium selenium, copper indium gallium. The solar cell substrate according to claim 8 or 9, which is at least one selected from the group consisting of selenium, indium tin oxide, cadmium tellurium, cadmium sulfide, zinc oxide, copper aluminum oxide, tin oxide, gallium nitride, and aluminum nitride. . 9. The insulator is at least one selected from the group consisting of zirconium oxide, hafnium oxide, tantalum oxide, aluminum oxide, titanium oxide, chromium oxide, and silicates, silicon oxide, silicon nitride, and sapphire. The board | substrate for solar cells as described in. A thin film containing at least one organic compound having an N—F bond is formed by spin coating, dipping, spraying, ink jetting, or doctor blade method so that the entire surface of the substrate has an N—F bond. The board | substrate for solar cells in any one of Claims 1-11 formed by apply | coating a compound. The thin film containing at least one organic compound having an NF bond is formed by applying droplets made of an organic compound having an NF bond to the surface of the substrate by an inkjet method. The solar cell substrate according to any one of 12. The solar cell substrate according to any one of claims 1 to 13, wherein the thin film containing at least one organic compound having an NF bond is a crystal, a polycrystal, an amorphous or a liquid. The solar cell substrate according to any one of claims 1 to 14, wherein the exposure is performed by irradiating visible light, ultraviolet light, infrared light, X-rays, an electron beam, an ion beam, or a laser beam. The solar cell according to any one of claims 1 to 15, which is obtained by removing a thin film containing at least one organic compound having an NF bond, and then wet-etching the surface of the substrate on which the thin film has been formed. Substrate. It is a manufacturing method of the substrate for solar cells in any one of Claims 1-16,
(1) forming a thin film containing at least one organic compound having an NF bond on the surface of the substrate (2) exposing the substrate; and (3) forming the thin film between the thin film and the substrate. The manufacturing method of the board | substrate for solar cells including the process removed with a residue. After step (3)
(4) The manufacturing method of the substrate for solar cells of Claim 17 including the process of wet-etching the surface in which the thin film containing at least 1 type of organic compound which has an NF bond of a board | substrate was formed. A solar cell provided with the board | substrate for solar cells in any one of Claims 1-16. The solar cell in which the thin film which consists of semiconductor materials is formed on the board | substrate for solar cells in any one of Claims 1-16. The solar cell by which the board | substrate for solar cells of Claim 10 is formed on the insulating material or the electrode material.

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