TW201639007A - Impurity diffusion composition, method for manufacturing semiconductor element using same, and solar cell - Google Patents

Abstract

The purpose of the present invention is to provide an impurity diffusion composition with which it is possible to obtain a uniform diffusion and excellent printability with respect to a semiconductor substrate. Another purpose of the present invention is to provide an impurity diffusion composition for forming a film having a sufficient masking property with respect to another impurity diffusion composition after diffusion. In order to achieve the above purposes, the present invention is configured as follows. An impurity diffusion composition containing (A) a wet gel measuring 1-50 [mu]m and (B) an impurity diffusion component.

Description

Impurity diffusion composition, method of manufacturing semiconductor device using the same, and solar cell

The present invention relates to an impurity diffusion composition for diffusing impurities in a semiconductor substrate, a method for producing a semiconductor device using the same, and a solar cell.

At present, in the production of a solar cell, when an n-type or p-type impurity diffusion layer is formed in a semiconductor substrate, a method of forming a diffusion source on a substrate and diffusing impurities into the semiconductor substrate by thermal diffusion is employed. The diffusion source is formed by a solution coating method of a chemical vapor deposition (CVD) method or a liquid impurity diffusion composition.

For example, in the case of using a liquid impurity diffusion composition, a thermal oxide film is first formed on the surface of the semiconductor substrate, and then a resist having a predetermined pattern is laminated on the thermal oxide film by photolithography. Resist. Then, using the resist as a mask, a portion of the thermal oxide film that is not covered by the resist is etched by an acid or a base, and the resist is peeled off to form a mask formed of a thermal oxide film. Then, an n-type or p-type diffusion composition is applied to adhere the diffusion composition to the portion of the opening of the mask. Thereafter, the impurity component in the composition is thermally diffused into the semiconductor substrate at 600 ° C to 1250 ° C to form an n-type or p-type impurity diffusion layer.

In the production of such a solar cell, in recent years, it has been studied to form a solar cell at low cost by simply performing patterning of an impurity diffusion source by a printing method or the like without using an existing photolithography technique.

In order to obtain excellent printability, a thixo agent such as silica fine particles is added to the impurity diffusion composition (see, for example, Patent Documents 1 to 2). By adding a thixotropic agent, the ratio of the viscosity (η ₁ ) at low shear stress to the viscosity (η ₂ ) at high shear stress (η ₁ /η ₂ ) can be increased, and the screen printed pattern can be improved. Precision. It is due to the following reasons. The impurity-dispersing composition containing a thixotropic agent is less likely to cause clogging of the screen during screen printing due to low viscosity under high shear stress, and is not easily caused to ooze immediately after printing due to high viscosity at low shear stress. Or the line width of the pattern becomes thicker. [Prior Art Document] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2010-56465. Patent Document 2: Japanese Patent Laid-Open No. 2014-175407

[Problems to be Solved by the Invention] However, the conventional impurity-dispersing composition containing a thixotropic agent has a problem that the uniformity of diffusion of impurities into the semiconductor substrate is low. It can be considered to be due to the following reasons. When heated for diffusion of impurities, voids are generated at the diffusion source due to thermal decomposition of the thixotropic agent or its agglomerates. Since the impurity concentration is low in the pores, a sufficient amount of impurities are not diffused in the semiconductor substrate at the portion where the pores are in contact with the semiconductor substrate. Further, even when voids are not formed, since the concentration of impurities in the aggregate of the thixotropic agent is low, diffusion at a portion where the aggregate contacts the semiconductor substrate is insufficient.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an impurity diffusion composition which can achieve excellent printability and uniform diffusion of a semiconductor substrate. Further, it is an object of the invention to provide an impurity diffusion composition which forms a film having sufficient masking properties for other impurity diffusion compositions after diffusion. [Means for solving the problem]

In order to solve the above problems, the impurity diffusion composition of the present invention has the following constitution. That is, an impurity diffusion composition containing (A) a wet gel having a size of 1 μm or more and 50 μm or less and (B) an impurity diffusion component. [Effects of the Invention]

According to the present invention, it is possible to provide an impurity diffusion composition which is excellent in printability of a substrate and uniformity of diffusion of impurities. Further, the impurity diffusion composition of the present invention can be used as a masking material for other impurity diffusion compositions.

The impurity diffusion composition of the present invention contains (A) a wet gel having a size of 1 μm or more and 50 μm or less and (B) an impurity diffusion component. Hereinafter, each component contained in the impurity diffusion composition of the present invention will be described in detail.

(A) Wet gel having a size of 1 μm or more and 50 μm or less The wet gel of the present invention is a liquid-preserving gel, specifically, a dispersion medium containing a solid and a liquid dispersion medium, and the smallest dispersion is formed. A three-dimensional network formed by physical interaction of a unit into which a gel having a dispersion medium enters. In order to obtain sufficient printability in screen printing or the like, there is a need for a large difference in viscosity at the time of high shear and low shear, that is, thixotropy. In the wet gel of the present invention, by using a relatively weak physical interaction such as a van der Waals force, a part or all of the interaction is cut by an external force such as shear to generate fluidity. When the external force does not act, no fluidity is generated, so that sufficient thixotropy can be obtained.

The physical interaction refers to an interaction other than a covalent bond. Specifically, in addition to the van der Waals force, an interionic interaction, a hydrogen bond, a dipole interaction, and the like can be cited.

In the present invention, the size of the wet gel is 1 μm or more and 50 μm or less. By having a size of 1 μm or more, thixotropy required for ensuring printability can be obtained, and by having a size of 50 μm or less, uniform impurity diffusibility can be obtained.

In addition, when the impurity diffusion composition is produced, foreign matter may be mixed in. Therefore, it is necessary to remove the foreign matter by filtration. However, since the screen opening diameter of the screen printing plate is about 50 μm, in order to avoid foreign matter due to printing. The resulting screen clogging is ideally filtered by a filter having an opening of 50 μm or less. If the size of the wet gel is 50 μm or less, the foreign matter removing step using the filter can be effectively carried out. The lower limit of the size of the wet gel is preferably 3 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more. Further, the upper limit is preferably 40 μm or less, more preferably 30 μm or less.

In the present invention, the projected area of the wet gel is calculated by image processing of an optical microscope photograph, and the diameter of a circle having the same area as the obtained projected area is defined as a single size of the wet gel. The case where the impurity-containing diffusion composition contains a wet gel having a size of 1 μm or more and 50 μm or less can be analyzed as follows. The impurity-diffusing composition was filtered through a filter having a pore size of 0.1 μm, and the solid matter remaining on the filter was taken to measure the presence or absence of gel phase phase transfer. If a gel volume phase transition is observed, the impure diffusion composition contains a wet gel. Differential scanning calorimetry (DSC) or the like can be used for the measurement of the gel volume phase transition.

Further, the size of the gel can be measured by observing a substantially elliptical gel taken on the filter with an optical microscope or the like. In the present invention, individual sizes of 50 gels were measured, and the average of these was set to the gel size.

The dispersion medium used in the present invention is not particularly limited as long as it forms a wet gel into the dispersed network structure, and water or various organic solvents can be used. Specific examples of the organic solvent include methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, rosinol, texanol, diethylene glycol methyl ethyl ether, and ethylene glycol. Ethyl acetate, ethylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, diacetone alcohol, propylene glycol monomethyl ether acetate, 3-methoxy-3-methyl-1-butanol , dipropylene glycol monomethyl ether, dipropylene glycol n-butyl ether, γ-butyrolactone, diethylene glycol monoethyl ether acetate, diethylene glycol butyl ether acetate, ethyl acetate ethyl acetate, N-methyl- 2-pyrrolidone, N,N-dimethylimidazolidinone, dipropylene glycol methyl ether acetate, 1,3-butanediol diacetate, diisobutyl ketone, propylene glycol tert-butyl ether, propylene glycol N-butyl ether, acetamidine acetone, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, and the like. These can also be used in combination.

The dispersoid used in the present invention can use a substance which stably forms a three-dimensional network structure by physical interaction. Specific examples thereof include cellulose, cellulose derivatives, sodium alginate, xanthan gum polysaccharides, gellan gum polysaccharides, and guar gums. Carbohydrate, carrageenan polysaccharide, locust bean gum polysaccharide, carboxyvinyl polymer, Disparlon 308 (manufactured by Nanben Chemical Co., Ltd.), hydrogenated castor oil, Flownon EC-121 ( Oxidized polyethylene, oxidized polyethylene and amide series, such as amide wax, special fatty acid, and Disparlon 4200-10 (manufactured by Nanben Chemical Co., Ltd.) Bentonite such as a mixture of a fatty acid-based polycarboxylic acid, a long-chain polyamine amide and a phosphoric acid, a special modified polyamine, or Organite D (the above is manufactured by Hojun Co., Ltd.), Montmorillonite, magnesian montmorillonite, iron montmorillonite, iron-magnesium montmorillonite, beidellite, aluminum beidellite, saponite ), aluminosilicate, laponite, aluminum niobate, aluminum magnesium niobate, hectorite, cerium oxide, colloidal alumina, calcium carbonate, etc., but cerium oxide, etc. Inorganic particles.

As the cerium oxide particles, RX200, R8200, RY200, R104, R976, RX3000, RY300, R202, RY200S, NX90G, NY50 (above, manufactured by Aerosil Co., Ltd.), HDKN20P, HDKT40, HDKH30, HDKH2000 can be used. , HDKH3004 (above is manufactured by Asahikasei Wacker Co., Ltd.), ST-30, ST-50, ST-N, ST-N-40, ST-O (above manufactured by Nissan Chemical Industry Co., Ltd.) Wait. These can also be used in combination.

The size of the inorganic particles is preferably a number average particle diameter of 5 nm or more and 500 nm or less. By setting it as the said range, moderate intermolecular interaction can be acquired, and high thixotropy can be given. Regarding the size of the inorganic particles, the number average particle diameter is preferably 7 nm or more and 100 nm or less, and most preferably 10 nm or more and 30 nm or less.

The size of the inorganic particles in the impurity diffusion composition of the present invention can be analyzed by the following method. The wet gel taken by the same method as the size measurement of the gel was uniformly dispersed in a solvent having a polarity close to that of the inorganic particles. A part of the dispersion was dropped onto a copper mesh and observed by a transmission electron microscope. The long diameters of the randomly selected 10 particles were measured, and the average value thereof was defined as the number average particle diameter.

The content of the dispersoid is preferably 0.5% by weight or more and 5% by weight or less in the impurity-diffusing composition. By this range, sufficient thixotropy can be obtained while a dense film can be formed.

The wet gel of the (A) size of the present invention having a size of 1 μm or more and 50 μm or less is not particularly limited, and can be produced by the following method. First, the dispersoid is mixed with the dispersion medium, and if necessary, heated while stirring. The obtained wet gel is pulverized by a pulverizer such as a three-rod roll mill, a beads mill, or a dyno-mill, thereby being adjusted to 1 μm or more and 50. Sizes below μm.

Since the wet gel has elasticity, it is difficult to adjust the size to 50 μm or less by simple stirring. In addition, it is necessary to apply a shear stress/compression force corresponding to the desired gel size, and it is important to select an appropriate pulverizer, and to adjust the roll spacing or bead size. As another method, after the dispersoid is mixed with the dispersion medium, other components may be added, and then the pulverization step may be carried out.

(B) Impurity diffusion component In the impurity diffusion composition of the present invention, the impurity diffusion component is a component for forming an impurity diffusion layer in a semiconductor substrate. The n-type impurity diffusion component is preferably a compound containing a group 15 element, of which a phosphorus compound is preferred. The p-type impurity diffusion component is preferably a compound containing a 13-member element, and among them, a boron compound is preferred.

The phosphorus compound can be exemplified by phosphorus pentoxide, phosphoric acid, polyphosphoric acid, methyl phosphate, dimethyl phosphate, trimethyl phosphate, ethyl phosphate, diethyl phosphate, triethyl phosphate, propyl phosphate, dipropyl phosphate. Phosphate esters such as esters, tripropyl phosphate, butyl phosphate, dibutyl phosphate, tributyl phosphate, phenyl phosphate, diphenyl phosphate, triphenyl phosphate, or methyl phosphite, dimethyl phosphite, Trimethyl phosphite, ethyl phosphite, diethyl phosphite, triethyl phosphite, propyl phosphite, dipropyl phosphite, tripropyl phosphite, butyl phosphite, dibutyl phosphite And phosphites such as tributyl phosphite, phenyl phosphite, diphenyl phosphite, and triphenyl phosphite. Among them, in terms of doping property, phosphoric acid, phosphorus pentoxide or polyphosphoric acid is preferred.

Examples of the boron compound include boric acid, boron trioxide, methyl boric acid, phenylboronic acid, trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, trioctyl borate, triphenyl borate, and the like. .

The SiO ₂ equivalent mass of the Si component contained in the impurity diffusion composition and the impurity atom mass contained in the impurity diffusion composition are preferably in the range of SiO ₂ : impurity atom = 99:1 to 30:70. By setting the range, excellent doping performance can be obtained. The converted mass ratio is further preferably in the range of 95:5 to 40:60, and most preferably in the range of 90:10 to 50:50. Here, the SiO ₂ equivalent mass of the Si component is a value obtained by converting the content of the Si component in the composition into the mass of SiO ₂ . This mass ratio can be calculated by inorganic analysis such as inductively coupled plasma (ICP) luminescence analysis or fluorescent X-ray analysis.

The impurity diffusion composition of the present invention preferably further contains (C) polyoxyalkylene. In the present invention, the term "polysiloxane" means a group having Si-O-Si bonds and containing five or more Si-O units as a unit. By containing a polyoxyalkylene, a more uniform film can be formed and a more uniform diffusion can be obtained. The polyoxyalkylene is not particularly limited, and a polyoxyalkylene obtained by polycondensation of a trifunctional organodecane is preferably used, and a polyoxyalkylene represented by the following formula (1) is particularly preferably used.

[Chemical 1]

In the formula, R ¹ represents an aryl group having 6 to 15 carbon atoms, and a plurality of R ^{1 's} may be the same or different. R ³ represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and a plurality of R ^{3 's} may be the same or different. R ² and R ^{4 each} represent a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a decyloxy group having 1 to 6 carbon atoms, and a plurality of R ² and R ⁴ may be the same or different. n and m represent the composition ratio (%) of the components in each bracket, and preferably n + m = 100, and n: m = 95: 5 - 25: 75.

Further, the terminal group is any one of hydrogen, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nonyloxy group having 1 to 6 carbon atoms, and an alkenyl group having 2 to 10 carbon atoms. .

The carbon number in the present invention means the total carbon number which also includes the base substituted on the base. For example, the methoxy-substituted butyl has a carbon number of 5. Further, the polyoxyalkylene represented by the formula (1) may be a block copolymer or a random copolymer.

By including a unit containing 25 mol% or more of an aryl group having 6 to 15 carbon atoms in terms of Si atom in the polyoxyalkylene, the crosslinking density of the polyoxyalkylene skeletons does not become too high, even if For thick film, crack is further suppressed. Thereby, cracks are less likely to occur in the calcination and thermal diffusion steps, so that the stability of diffusion of impurities can be improved. In addition, the masking property of the impurity diffusion layer to other impurity diffusion compositions can be further improved after thermal diffusion of impurities. In order to maintain the masking property, it is preferable that the film thickness after the diffusion is large, and it is preferable to use the impurity diffusion composition of the present invention which is less likely to cause cracks even in the case of a thick film. Further, even in a composition in which a thermally decomposable component such as a thickener is added, pores formed by thermal decomposition can be filled by a reflow effect of decane, and a void can be formed. Dense film. Therefore, it is not easily affected by the environment at the time of diffusion, and high opacity to other impurities can be obtained.

On the other hand, when the unit containing an aryl group in the polyoxyalkylene is 95 mol% or less in terms of Si atom, the peeling residue after diffusion can be removed. It is considered that the residue is a carbide which is not completely decomposed and volatilized by the organic matter, and not only hinders the doping property, but also increases the contact resistance of the electrode formed later and causes the efficiency of the solar cell to decrease. When the unit containing an aryl group exceeds 95 mol%, it is considered that the composition film becomes too dense and the residue is likely to be generated before the organic component is completely decomposed and volatilized.

From the viewpoint of further improving the crack resistance, the shielding property, the storage stability, and the effect of reducing the diffusion environment, the polysiloxane containing the carbon number of 6 to 15 in the polysiloxane diffusing composition is contained. The unit is more preferably 35 mol% or more, and still more preferably 40 mol% or more. Further, in order not to be affected by the environment or the film thickness, no residue is generated, and it is preferable that the unit containing an aryl group is 80 mol% or less. That is, it is particularly preferable that n: m = 80: 20 to 40: 60. When R ³ is an alkyl group, by setting the carbon number to 6 or less, the generation of the residue can be suppressed, and the reflow effect by the aryl group of R ¹ can be sufficiently exhibited.

The aryl group having 6 to 15 carbon atoms in R ¹ of the formula (1) may be either an unsubstituted or substituted group, and may be selected depending on the properties of the composition. Specific examples of the aryl group having 6 to 15 carbon atoms include a phenyl group, a p-tolyl group, an m-tolyl group, an o-tolyl group, a p-hydroxyphenyl group, a p-styryl group, a p-methoxyphenyl group, and a naphthyl group. Preferred is phenyl, p-tolyl, m-tolyl.

The alkyl group having 1 to 6 carbon atoms and the alkenyl group having 2 to 10 carbon atoms in R ³ of the formula (1) may be either an unsubstituted or substituted group, and may be carried out according to the characteristics of the composition. select.

Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, n-hexyl group, trifluoromethyl group, and 3,3,3. -Trifluoropropyl, 3-methoxy-n-propyl, glycidyl, 3-glycidoxypropyl, 3-aminopropyl, 3-mercaptopropyl, 3-isocyanatepropyl, as a residue On the other hand, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, and a t-butyl group having a carbon number of 4 or less are preferable.

Specific examples of the alkenyl group having 2 to 10 carbon atoms include a vinyl group, a 1-propenyl group, a 1-butenyl group, a 2-methyl-1-propenyl group, a 1,3-butadienyl group, and a 3-methyl group. Oxy-1-propenyl, 3-propenyloxypropyl, 3-methylpropenyloxypropyl, in terms of residue, vinyl or 1-propenyl having a carbon number of 4 or less is particularly preferable. , 1-butenyl, 2-methyl-1-propenyl, 1,3-butadienyl, 3-methoxy-1-propenyl.

The alkoxy group having 1 to 6 carbon atoms and the decyloxy group having 1 to 6 carbon atoms in R ² and R ⁴ in the formula (1) may be either an unsubstituted or substituted group, and may be The characteristics of the composition are selected.

Specific examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group, a n-butoxy group, and a third butoxy group.

Specific examples of the decyloxy group having 1 to 6 carbon atoms include an ethoxycarbonyl group, a propenyloxy group, an acryloxy group, and a benzamidine group.

Further, the polyoxyalkylene of the present invention preferably has a 20% thermal decomposition temperature of 550 ° C or higher. As a result, the organic component other than the polysiloxane can be thermally decomposed and completely removed, whereby the reflux effect by the decane can be obtained, so that a denser film with less residue can be obtained. Here, the 20% thermal decomposition temperature is a temperature at which the weight of the polyoxyalkylene is reduced by 20% by thermal decomposition. The thermal decomposition temperature can be measured using a thermogravimetric analyzer (thermogravimetric analyzer (TGA)) or the like.

As a specific example of the organodecane which is a raw material of the unit of the formula (1) having R ¹ and R ² , a phenyltrimethoxydecane, a phenyltriethoxydecane or a p-hydroxyphenyltrimethoxy group can be preferably used. Decane, p-tolyltrimethoxydecane, p-styryltrimethoxydecane, p-methoxyphenyltrimethoxydecane, 1-naphthyltrimethoxynonane, 2-naphthyltrimethoxynonane, 1- Naphthyltriethoxydecane, 2-naphthyltriethoxydecane. Among them, phenyltrimethoxydecane, p-tolyltrimethoxydecane, and p-methoxyphenyltrimethoxydecane are particularly preferable.

Specific examples of the organic decane which is a raw material of the unit having R ³ and R ⁴ in the general formula (1) include methyltrimethoxydecane, methyltriethoxydecane, and methyltriisopropoxydecane. Methyl tri-n-butoxy decane, ethyl trimethoxy decane, ethyl triethoxy decane, ethyl triisopropoxy decane, ethyl tri-n-butoxy decane, n-propyl trimethoxy decane, N-propyl triethoxy decane, n-butyl trimethoxy decane, n-butyl triethoxy decane, glycidyl trimethoxy decane, vinyl trimethoxy decane, vinyl triethoxy decane, three Fluoromethyltrimethoxydecane, trifluoromethyltriethoxydecane, 3,3,3-trifluoropropyltrimethoxydecane, 3-aminopropyltrimethoxydecane, 3-aminopropyl Triethoxy decane, 3-mercaptopropyltrimethoxydecane, and the like. Further, the organic decane may be used singly or in combination of two or more.

The polyoxyalkylene represented by the formula (1) can be obtained by hydrolyzing the organodecane compound, and subjecting the hydrolyzate to a condensation reaction in the presence of a solvent or without a solvent. The various conditions of the hydrolysis reaction, for example, the acid concentration, the reaction temperature, the reaction time, and the like, may be appropriately set in consideration of the reaction scale, the size and shape of the reaction vessel, and the like. For example, it is preferred to add the organodecane compound in a solvent for 1 minute to 180 minutes. After the acid catalyst and water, the reaction is carried out at room temperature to 110 ° C for 1 minute to 180 minutes. By carrying out the hydrolysis reaction under such conditions, the impatient reaction can be suppressed. The reaction temperature is more preferably from 30 ° C to 130 ° C.

The hydrolysis reaction is preferably carried out in the presence of an acid catalyst. Examples of the acid catalyst include hydrogen halide-based inorganic acids such as hydrochloric acid, hydrobromic acid, and hydroiodic acid; and other inorganic acids such as sulfuric acid, nitric acid, phosphoric acid, hexafluorophosphoric acid, hexafluoroantimonic acid, boric acid, tetrafluoroboric acid, and chromic acid; Sulfonic acid such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid; acetic acid, citric acid, formic acid, gluconic acid, lactic acid, oxalic acid, tartaric acid, pyruvic acid, citric acid, succinic acid , carboxylic acid such as fumaric acid or malic acid. From the viewpoint of doping, the acid catalyst of the present invention preferably contains no atoms other than ruthenium, hydrogen, carbon, oxygen, nitrogen, or phosphorus, and preferably phosphoric acid, formic acid, acetic acid, or carboxylic acid. Acid catalyst. Among them, phosphoric acid is preferred.

The content of the acid catalyst is preferably from 0.1 part by weight to 5 parts by weight based on 100 parts by weight of all the organic decane compound used in the hydrolysis reaction. By setting the amount of the acid catalyst to the above range, the hydrolysis reaction can be easily controlled to make it necessary and sufficient.

The solvent to be used in the hydrolysis reaction of the organic decane compound and the condensation reaction of the hydrolyzate is not particularly limited, and may be appropriately selected in consideration of stability, coatability, volatility, and the like of the resin composition. Further, two or more solvents may be combined, and the reaction may be carried out without a solvent. Specific examples of the solvent include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tert-butanol, 1-methoxy-2-propanol, pentanol, and 4-methyl-2. -pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxy-1-butanol, 1-tert-butoxy-2-propanol, diacetone alcohol, rosinol, Alcohols such as Texanol; glycols such as ethylene glycol and propylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol Tributyl ether, propylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethyl ether, diethylene glycol methyl ethyl ether, dipropylene glycol n-butyl ether, dipropylene glycol Ethers such as monomethyl ether, diisopropyl ether, di-n-butyl ether, diphenyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, ethylene glycol monobutyl ether; methyl ethyl Ketone, acetoacetone, methyl propyl ketone, methyl butyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, 2-heptanone, diisobutyl ketone, cyclohexanone, Ketones such as cycloheptanone; guanamines such as dimethylformamide and dimethylacetamide Ethyl acetate, propyl acetate, butyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, Glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, two Ethylene glycol butyl ether acetate, 1,3-butylene glycol diacetate, diethylene glycol diethyl ether acetate, dipropylene glycol methyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, Acetate such as triethyl decyl glycerin; aromatic or aliphatic hydrocarbon such as toluene, xylene, hexane, cyclohexane, ethyl benzoate, naphthalene, 1,2,3,4-tetrahydronaphthalene, γ- Butyrolactone, N-methyl-2-pyrrolidone, N,N-dimethylimidazolidinone, dimethyl azine, propylene carbonate, and the like.

When a solvent is produced by a hydrolysis reaction, it can also be hydrolyzed without a solvent. It is also preferred to adjust the concentration to a suitable concentration as a resin composition by further adding a solvent after completion of the reaction. Further, after the hydrolysis, the alcohol may be distilled off under heating and/or reduced pressure, and an appropriate amount of alcohol may be removed, and then a preferred solvent may be added.

The amount of the solvent used in the hydrolysis reaction is preferably 80 parts by weight or more and 500 parts by weight or less based on 100 parts by weight of the total of the organic decane compound. By setting the amount of the solvent to the above range, the hydrolysis reaction can be easily controlled to make it necessary and sufficient. Further, the water used in the hydrolysis reaction is preferably ion-exchanged water. The amount of water can be arbitrarily selected, and is preferably used in the range of 1.0 mol to 4.0 mol with respect to 1 mol of Si atom.

The impurity diffusion composition of the present invention preferably contains a solvent. The solvent is not particularly limited, but a solvent having a boiling point of 100 ° C or higher is preferred from the viewpoint of further improving the printability in the case of a screen printing method, a spin coating method, or the like. When the boiling point is 100 ° C or more, for example, when the printing plate used in the screen printing method prints the impurity diffusion composition, the impurity diffusion composition can be prevented from drying and adhering to the printing plate.

The content of the solvent having a boiling point of 100 ° C or higher is preferably 20% by weight or more based on the total amount of the solvent. The solvent having a boiling point of 100 ° C or more can be exemplified by diethylene glycol methyl ethyl ether (boiling point: 176 ° C), ethylene glycol monoethyl ether acetate (boiling point: 156.4 ° C), ethylene glycol monomethyl ether acetate (boiling point 145). °C), methyl lactate (boiling point 145 ° C), ethyl lactate (boiling point 155 ° C), diacetone alcohol (boiling point 169 ° C), propylene glycol monomethyl ether acetate (boiling point 145 ° C), 3-methoxy-3 -Methyl-1-butanol (boiling point 174 ° C), dipropylene glycol monomethyl ether (boiling point 188 ° C), dipropylene glycol n-butyl ether (boiling point 229 ° C), γ-butyrolactone (boiling point 204 ° C), diethylene Alcohol monoethyl ether acetate (boiling point 217 ° C), diethylene glycol butyl ether acetate (boiling point 246 ° C), ethyl acetate ethyl acetate (boiling point 181 ° C), N-methyl-2-pyrrolidone (boiling point) 204 ° C), N,N-dimethylimidazolidinone (boiling point 226 ° C), dipropylene glycol methyl ether acetate (boiling point 213 ° C), 1,3-butylene glycol diacetate (boiling point 232 ° C), Diisobutyl ketone (boiling point 168 ° C), propylene glycol tert-butyl ether (boiling point 151 ° C), propylene glycol n-butyl ether (boiling point 170 ° C), acetamidine acetone (boiling point 140 ° C), diethylene glycol monobutyl ether (boiling) 171 ℃), diethylene glycol monobutyl ether acetate (boiling point 245 ℃).

Further, specific examples of the solvent having a boiling point of less than 100 ° C include alcohols such as methanol, ethanol, propanol, isopropanol, and third butanol; ethers such as diethyl ether and diisopropyl ether; and methyl ethyl ketone; Ketones; acetates such as isopropyl acetate, ethyl acetate, propyl acetate, n-propyl acetate, 3-methyl-3-methoxybutyl acetate; aliphatic hydrocarbons such as hexane and cyclohexane Wait.

The impurity diffusion composition of the present invention may also contain a surfactant. By including a surfactant, coating unevenness is improved, and a uniform coating film can be obtained. As the surfactant, a fluorine-based surfactant or an anthrone-based surfactant can be preferably used.

Specific examples of the fluorine-based surfactant include a fluorine-based surfactant having a compound having a fluorocarbon or a fluoroalkyl group in at least any of a terminal, a main chain and a side chain: 1, 1, 2, 2 - 4 Fluorinyl (1,1,2,2-tetrafluoropropyl)ether, 1,1,2,2-tetrafluorooctylhexyl ether, octaethylene glycol di(1,1,2,2-tetrafluoro Butyl)ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl)ether, octapropylene glycol bis(1,1,2,2-tetrafluorobutyl)ether, hexapropylene glycol Bis(1,1,2,2,3,3-hexafluoropentyl)ether, sodium perfluorododecylsulfonate, 1,1,2,2,8,8,9,9,10,10 - decafluorododecane, 1,1,2,2,3,3-hexafluorodecane, N-[3-(perfluorooctanesulfonamide)propyl]-N,N'-dimethyl -N-carboxymethylene ammonium betaine, perfluoroalkylsulfonamide propyltrimethylammonium salt, perfluoroalkyl-N-ethylsulfonylglycine, bis (N-perfluoro) octylsulfonyl-N-ethylaminoethyl ester, monoperfluoroalkylethyl phosphate, and the like. In addition, commercially available products include Megafac F142D, Megafac F172, Megafac F173, Megafac F183, Megafac F444, Megafac F475, Megafac F477 (above manufactured by Dainippon Ink And Chemicals Co., Ltd.), Eftop EF301, Eftop 303, Eftop 352 (manufactured by New Akita Chemical Co., Ltd.), Fluorad FC-430, Fluorad FC-431 (manufactured by Sumitomo 3M Co., Ltd.), AsahiGuard AG710, Surflon S-382, Surflon SC-101, Surflon SC-102, Surflon SC-103, Surflon SC-104, Surflon SC-105, Surflon SC-106 (manufactured by Asahi Glass Co., Ltd.), BM-1000, BM-1100 (manufactured by Yushang Co., Ltd.), NBX-15, FTX-218 A fluorine-based surfactant such as DFX-218 (manufactured by Neos Co., Ltd.).

Commercial products of an anthrone-based surfactant include SH28PA, SH7PA, SH21PA, SH30PA, and ST94PA (above, manufactured by Toray Dow Corning Co., Ltd.), BYK067A, BYK310, BYK322, BYK331, BYK333, and BYK355. (The above is manufactured by BYK-Chemie Japan Co., Ltd.) and the like. Further, in the case where the anthrone-based surfactant also conforms to the (C) polyoxane, the indolinone-based surfactant is calculated as (C) polydecane in the calculation of the content ratio. .

In the case of addition, the content of the surfactant is preferably from 0.0001% by weight to 1% by weight in the impurity-diffusing composition.

In order to adjust the viscosity, the impurity diffusion composition of the present invention preferably contains a thickener. Thereby, the coating can be performed in a more precise pattern by a printing method such as screen printing. Further, the thickener is a component which is independent of the solid matter remaining on the filter when the impurity-diffusing composition is filtered by a filter having a pore size of 0.1 μm.

Examples of the thickener include polyvinylpyrrolidone, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyurethane resin, polyurea resin, and the like. Polyimine resin, polyamide resin, epoxy resin, polystyrene resin, polyester resin, synthetic rubber, natural rubber, polyacrylic acid, various acrylic resins, polyethylene glycol, polyethylene oxide, Polypropylene glycol, polypropylene oxide, silicone oil, sodium alginate, cellulose, cellulose derivatives, starch, starch derivatives, Sanxian gum polysaccharides, orchid gum polysaccharides, guar gum Polysaccharide, carrageenan polysaccharide, locust bean gum polysaccharide, carboxyvinyl polymer, hydrogenated castor oil, hydrogenated castor oil and fatty acid amide wax, special fatty acid, oxidized polyethylene, oxidized polyethylene A mixture with a guanamine system, a fatty acid polycarboxylic acid, a long chain polyamine amide and a phosphate salt, a special modified polyamine system, and the like.

In the inorganic system, examples thereof include bentonite, montmorillonite, magnesium montmorillonite, iron montmorillonite, iron-magnesium montmorillonite, beidellite, aluminum beidellite, saponite, aluminosilicate, and laponite. , aluminum niobate, aluminum magnesium niobate, organic hectorite, fine particles of cerium oxide, colloidal alumina, calcium carbonate and the like. These can be used in combination.

Moreover, the commercial item of the organic thickener can mention the following.

Acrylic thickeners include: #2434T, KC-7000, KC-1700P (above is manufactured by Kyoeisha Chemical Co., Ltd.), AC-10LHPK, AC-10SHP, 845H, PW-120 (above is East Asia Synthetic Shares) Ltd. manufactured) and so on.

Among the polysaccharide thickeners, thickeners other than the cellulose derivative include Viscarin PC209, Viscarin PC389, SeaKem XP8012 (above, manufactured by FMC Chemical Co., Ltd.), CAM-H, GJ-182, and SV-300. , LS-20, LS-30, XGT, XGK-D, G-100, LG-10 (all are Mitsubishi Corporation).

Among the polysaccharide thickeners, the cellulose derivatives may be: 1110, 1120, 1130, 1140, 1150, 1160, 1170, 1180, 1190, 2200, 2260, 2280, 2450 (above is Daicel FineChem) )), Ethocel 10cP, Ethocel 20cP, Ethocel 45cP, Ethocel 100cP, Ethocel 200cP (above, manufactured by Nisshin Chemical Co., Ltd.).

Hydrogenated castor oil thickeners include Disparlon 308, NAMLONT-206 (above, manufactured by Nanben Chemical Co., Ltd.), T-20SF, T-75F (above, manufactured by Ito Oil Co., Ltd.), and the like.

Oxidized polyethylene thickeners are D-10A, D-120, D-120-10, D-1100, DS-525, DS-313 (above manufactured by Ito Oil Co., Ltd.), Disparlon 4200-20, Disparlon PF-911, Disparlon PF-930, Disparlon 4401-25X, Disparlon NS-30, Disparlon NS-5010, Disparlon NS-5025, Disparlon NS-5810, Disparlon NS-5210, Disparlon NS-5310 (above is Nanben Chemical Co., Ltd.) The company manufactures), Flownon SA-300, Flownon SA-300H (above is manufactured by Kyoeisha Chemical Co., Ltd.), PEO-1, PEO-3 (above, manufactured by Sumitomo Seika Co., Ltd.).

The guanamine thickeners are T-250F, T-550F, T-850F, T-1700, T-1800, T-2000 (above manufactured by Ito Oil Co., Ltd.), Disparlon 6500, Disparlon 6300, Disparlon 6650, Disparlon 6700, Disparlon 3900EF (above manufactured by Nanben Chemical Co., Ltd.), Talen 7200, Talen 7500, Talen 8200, Talen 8300, Talen 8700, Talen 8900, Talen KY-2000, KU-700, Talen M-1020, Talen VA -780, Talen VA-750B, Talen 2450, Flownon SD-700, Flownon SDR-80, Flownon EC-121 (above, manufactured by Kyoeisha Chemical Co., Ltd.).

Further, commercially available products of inorganic thickeners include the following.

Bentonite thickeners can be listed as: Bengel, Bengel HV, Bengel HVP, Bengel F, Bengel FW, Bengel Bright 11, Bengel A, Bengel W-100, Bengel W-100U, Bengel W-300U, Bengel SH, MultiBen, S -Ben, S-Ben C, S-Ben E, S-Ben W, S-Ben P, S-Ben WX, Organite, Organite D (above, manufactured by Hojun Co., Ltd.).

Examples of microparticle cerium oxide thickeners include: AEROSIL R972, AEROSIL R974, AEROSIL NY50, AEROSIL RY200S, AEROSIL RY200, AEROSIL RX50, AEROSIL NAX50, AEROSIL RX200, AEROSIL RX300, AEROSIL VPNKC130, AEROSIL R805, AEROSIL R104, AEROSIL R711, AEROSIL OX50, AEROSIL 50, AEROSIL 90G, AEROSIL 130, AEROSIL 200, AEROSIL 300, AEROSIL 380 (above is manufactured by Aerosil Co., Ltd.), WACKER HDK S13, WACKER HDK V15, WACKER HDK N20, WACKER HDK N20P, WACKER HDK T30, WACKER HDK T40, WACKER HDK H15, WACKER HDK H18, WACKER HDK H20, WACKER HDK H30 (above, manufactured by Asahi Kasei Co., Ltd.).

The thickener preferably has a 90% thermal decomposition temperature of 400 ° C or less in terms of forming a dense film or reducing residue. Specifically, polyethylene glycol, polyethylene oxide, polypropylene glycol, polypropylene oxide, cellulose derivatives, and various acrylate resins are preferred, of which polyethylene oxide and polyepoxy are preferred. Propane or acrylate resin. In terms of storage stability, the cellulose derivative or the acrylate resin is more preferably a cellulose derivative from the viewpoint of printability. Here, the 90% thermal decomposition temperature is a temperature at which the weight of the thickener is reduced by 90% due to thermal decomposition. The thermal decomposition temperature can be measured using a thermogravimetric measuring device (TGA) or the like.

Examples of the acrylate-based resin include polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, and polypropyl acrylate. Polyacrylates such as polybutyl acrylate, polyhydroxyethyl methacrylate, polybenzyl methacrylate, polyglycidyl methacrylate, and copolymers thereof. In the case of the copolymer, the acrylate component may be 60 mol% or more in terms of a polymerization ratio, and as the other copolymer component, a component which can be vinyl-polymerized such as polyacrylic acid or polystyrene may be copolymerized.

Further, as for the polyethylene oxide and the polypropylene oxide, the two copolymers are also preferable. The acrylate resin, polyethylene oxide, and polypropylene oxide are preferably those having a weight average molecular weight of 100,000 or more and having a high thickening effect.

The content of the thickener is preferably 3% by weight or more and 20% by weight or less in the impurity-diffusing composition. By this range, a sufficient viscosity adjustment effect can be obtained, and at the same time, a dense film can be formed.

The viscosity of the impurity diffusion composition of the present invention is not limited, and can be appropriately changed depending on the printing method and the film thickness. Here, for example, in the case of a screen printing method which is one of preferable printing methods, the viscosity of the diffusion composition is preferably 5,000 mPa·s or more. The reason for this is that the bleeding of the printed pattern can be suppressed to obtain a good pattern. Further, a preferred viscosity is 10,000 mPa·s or more. The upper limit is not particularly limited, and is preferably 100,000 mPa·s or less from the viewpoint of storage stability or workability. Here, in the case where the viscosity is less than 1,000 mPa·s, it is based on Japanese Industrial Standards (JIS) Z 8803 (1991) "Solid Viscosity - Measurement Method", using an E-type digital viscometer at a number of revolutions of 5 When the viscosity is 1,000 mPa·s or more, the value measured by rpm is measured by a B-type digital viscometer at a number of revolutions of 5 rpm based on JIS Z 8803 (1991) "Solid viscosity-measurement method". value.

Thixotropy can be determined from the ratio of the viscosity at different numbers of revolutions obtained by the viscosity measurement method. In the present invention, the ratio (η ₅ /η ₅₀ ) of the viscosity (η ₅₀ ) at a revolution of 50 rpm to the viscosity (η ₅ ) at a number of revolutions of 5 rpm is defined as thixotropy. In order to perform pattern formation with high precision by screen printing, the thixotropy is preferably 1.5 or more and less than 5.0, more preferably 2.0 or more and less than 3.0.

The solid content concentration of the impurity diffusion composition of the present invention is not particularly limited, and a preferred range is from 1% by weight to 90% by weight. When the concentration is lower than the concentration range, the coating film thickness becomes too thin, and the desired doping property is not easily obtained. When the concentration is higher than the concentration range, the storage stability is lowered.

A method of forming an impurity diffusion layer using the impurity diffusion composition of the present invention and a method of producing a semiconductor element using the same will be described. A method of manufacturing a semiconductor device according to the present invention includes the steps of: printing an impurity diffusion composition on a semiconductor substrate to form an impurity diffusion composition film; and forming a impurity diffusion layer by diffusing the impurity from the impurity diffusion composition film to form an impurity diffusion layer . Here, the printing is preferably screen printing. Further, it is preferable to include a step of forming a second impurity diffusion composition film by using the impurity diffusion composition film as a mask layer and printing an impurity diffusion composition containing a second impurity different from the impurity.

Further, the method for producing a semiconductor device of the present invention includes the steps of: printing the impurity diffusion composition on a semiconductor substrate to form a first impurity diffusion composition film; and printing an impurity diffusion composition containing the second impurity to form a second impurity; a step of diffusing the composition film; and a step of forming the first impurity diffusion layer and the second impurity diffusion layer by simultaneously heating the first impurity diffusion composition film and the second impurity diffusion composition film.

Hereinafter, a method of forming an impurity diffusion layer which can be applied to the method of manufacturing the semiconductor elements will be described using a drawing. Furthermore, as an example, the method applicable to the method of manufacturing a semiconductor device of the present invention is not limited to these.

1(a) to 1(e) show a method of forming an impurity diffusion layer, comprising: a step of coating an impurity diffusion composition; and diffusing an n-type impurity from the impurity diffusion composition to the semiconductor substrate And the step of diffusing the p-type impurity to the semiconductor substrate by using the impurity diffusion composition as a mask. 2(f) to 2(h) illustrate a method of manufacturing a semiconductor element using the impurity diffusion layer as an example of a method of manufacturing a back surface bonded solar cell.

First, as shown in FIG. 1(a), an n-type impurity diffusion composition 2 is formed on the semiconductor substrate 1.

Examples of the semiconductor substrate 1 include n-type single crystal germanium having an impurity concentration of 10 ¹⁵ atoms/cm ³ to 10 ¹⁶ atoms/cm ³ , polycrystalline germanium, and a crystalline germanium substrate in which other elements such as germanium or carbon are mixed. A p-type crystal germanium or a semiconductor other than germanium can also be used. The semiconductor substrate 1 is preferably a substantially quadrangular shape having a thickness of 50 μm to 300 μm and an outer shape of 100 mm to 250 mm. Further, in order to remove slice damage or a natural oxide film, it is preferred to etch the surface in advance using a hydrofluoric acid solution or an alkali solution.

A protective film may be formed on the light receiving surface of the semiconductor substrate 1. As the protective film, a known protective film such as ruthenium oxide or tantalum nitride which is formed by a method such as a CVD (Chemical Vapor Deposition) method or a spin-on glass (SOG) method can be applied.

Examples of the method for forming the n-type impurity diffusion composition 2 include a screen printing method, an inkjet printing method, a slit coating method, a spray coating method, a relief printing method, and a gravure printing method. After the coating film is formed by these methods, the n-type impurity diffusion composition 2 is preferably dried in a range of 50 to 200 ° C for 30 seconds to 30 minutes by using a hot plate, an oven or the like. . When the masking property of the p-type impurity is considered, the film thickness of the n-type impurity diffusion composition 2 after drying is preferably 200 nm or more, and is preferably 5 μm or less from the viewpoint of crack resistance.

Next, as shown in FIG. 1(b), the impurity in the n-type impurity diffusion composition 2 is diffused into the semiconductor substrate 1 to form the n-type impurity diffusion layer 3. The diffusion method of the n-type impurity can be carried out by a known thermal diffusion method, and for example, electric heating, infrared heating, laser heating, microwave heating or the like can be used.

The time and temperature of thermal diffusion can be suitably set in such a manner that the diffusion characteristics required for the diffusion concentration and diffusion depth of the impurity can be obtained. For example, by heating and diffusing at 800 ° C or more and 1200 ° C or less for 1 minute to 120 minutes, an n-type impurity diffusion layer having a surface impurity concentration of 10 ¹⁹ to 10 ²¹ can be formed.

The diffusion environment is not particularly limited, and it can be carried out in the air, or an inert gas such as nitrogen or argon can be used, and the amount of oxygen in the environment can be appropriately controlled. From the viewpoint of shortening the diffusion time, it is preferred to set the oxygen concentration in the environment to 3% or less. Further, it is also possible to carry out calcination in the range of 200 ° C to 850 ° C before the diffusion.

After the n-type impurity is diffused to the semiconductor substrate 1, the n-type impurity diffusion composition 2 can be peeled off by the peeling of a known etching liquid such as hydrofluoric acid. Thereafter, printing of the p-type impurity diffusion composition and diffusion of the p-type impurity may be performed on the semiconductor substrate 1 on which the n-type impurity diffusion layer is formed, or the n-type impurity diffusion composition 2 may not be peeled off as described below. Printing of the p-type impurity diffusion composition and diffusion of the p-type impurity are preferable from the viewpoint of reducing the number of steps.

After the diffusion of the n-type impurity, the n-type impurity diffusion composition 2 is calcined as needed, and then, as shown in FIG. 1(c), the n-type impurity diffusion composition 2 is used as a mask to coat the p-type impurity diffusion composition. Matter 4. In this case, as shown in FIG. 1(c), the p-type impurity diffusion composition 4 may be formed on the entire surface, or may be formed only in the portion where the n-type impurity diffusion composition 2 is not present. Further, a part of the p-type impurity diffusion composition 4 may be applied so as to overlap the n-type impurity diffusion composition 2.

The method of coating the p-type impurity diffusion composition 4 can be exemplified in the method of forming the n-type impurity diffusion composition.

Next, as shown in FIG. 1(d), the n-type impurity diffusion composition 2 after calcination is used as a mask layer, and the p-type impurity diffusion composition 4 is diffused to the semiconductor substrate 1 to form a p-type impurity diffusion layer 5. The method of diffusing the p-type impurity may be the same as the method of diffusing the n-type impurity.

Next, as shown in FIG. 1(e), the n-type impurity diffusion composition 2 and the p-type impurity diffusion composition 4 formed on the surface of the semiconductor substrate 1 are removed by a known etching method. The material to be used for the etching is not particularly limited, and for example, a material containing at least one of hydrogen fluoride, ammonium, phosphoric acid, sulfuric acid, and nitric acid as an etching component and containing water or an organic solvent as a component other than the above is preferable. By the above steps, an n-type and p-type impurity diffusion layer can be formed on the semiconductor substrate. By setting this step, the steps can be simplified as compared with the conventional method.

Here, an example in which the p-type impurity diffusion composition is coated and diffused after application and diffusion of the n-type impurity diffusion composition is exemplified, but may be performed after application/diffusion of the p-type impurity diffusion composition. Application and diffusion of a type of impurity diffusion composition.

Next, a method of manufacturing the semiconductor device of the present invention will be described by taking a back junction type solar cell as an example using FIGS. 2(f) to 2(h). First, as shown in FIG. 2(f), the protective film 6 is formed on the entire back surface of the semiconductor substrate 1 on which the n-type impurity diffusion layer 3 and the p-type impurity diffusion layer 5 are formed on the back surface. Then, as shown in FIG. 2(g), the protective film 6 is patterned by an etching method or the like to form a protective film opening 6a. Further, as shown in FIG. 2(h), the electrode paste is patterned and fired in a region including the protective film opening 6a by a stripe coating method or a screen printing method, thereby forming an n-type contact electrode. 7 and p-type contact electrode 8. Thereby, the back junction type solar cell 9 can be obtained.

Further, a method of forming another impurity diffusion layer using the impurity diffusion composition of the present invention will be described with reference to Figs. 3(a) to 3(d). 3(a) to 3(d) show a method of forming an impurity diffusion layer, comprising: a step of forming a pattern using an n-type impurity diffusion composition; and coating the n-type impurity diffusion composition as a mask a step of diffusing the p-type impurity diffusion composition; and a step of diffusing the n-type and p-type impurities from the n-type impurity diffusion composition and the p-type impurity diffusion composition into the semiconductor substrate.

First, as shown in FIG. 3(a), the n-type impurity diffusion composition 2 of the present invention is patterned on the semiconductor substrate 1. Next, if the n-type impurity diffusion composition 2 is calcined as needed, as shown in FIG. 3(b), the p-type impurity diffusion composition 4 is coated with the n-type impurity diffusion composition 2 as a mask. Then, as shown in FIG. 3(c), the n-type impurity diffusion component in the n-type impurity diffusion composition 2 and the p-type impurity diffusion component in the p-type impurity diffusion composition 4 are simultaneously diffused into the semiconductor substrate 1 to form The n-type impurity diffusion layer 3 and the p-type impurity diffusion layer 5 are used. The coating method, the calcination method, and the diffusion method of the impurity diffusion composition may be the same as those described above.

Next, as shown in FIG. 3(d), the n-type impurity diffusion composition 2 and the p-type impurity diffusion composition 4 formed on the surface of the semiconductor substrate 1 are removed by a known etching method. By the above steps, an n-type and p-type impurity diffusion layer can be formed on the semiconductor substrate. By setting this step, the steps can be further simplified as compared with the conventional method.

Further, a method of forming another impurity diffusion layer using the impurity diffusion composition of the present invention will be described with reference to FIGS. 4(a) to 4(d).

As shown in FIG. 4(a), the p-type impurity diffusion composition 4 of the present invention is applied onto the semiconductor substrate 1. After the p-type impurity diffusion composition 4 is calcined as needed, as shown in FIG. 4(b), an n-type impurity is coated on the surface of the semiconductor substrate 1 opposite to the surface on which the p-type impurity diffusion composition 4 is formed. Diffusion composition 2. Then, as shown in FIG. 4(c), the p-type impurity diffusion composition 4 and the n-type impurity diffusion composition 2 are simultaneously diffused into the semiconductor substrate 1 to form the p-type impurity diffusion layer 5 and the n-type impurity diffusion layer 3. The coating method, the calcination method, and the diffusion method of the impurity diffusion composition may be the same as those described above.

Then, as shown in FIG. 4(d), the p-type impurity diffusion composition 4 and the n-type impurity diffusion composition 2 formed on the surface of the semiconductor substrate 1 are removed by a known etching method. By the above steps, an n-type and p-type impurity diffusion layer can be formed on the semiconductor substrate. By setting this step, the steps can be simplified as compared with the conventional method.

Here, an example in which the p-type impurity diffusion composition is applied and then the n-type impurity diffusion composition is applied is described. However, the application of the p-type impurity diffusion composition may be performed after the application of the n-type impurity diffusion composition. .

The present invention is not limited to the above-described embodiments, and various modifications such as design changes may be applied based on the knowledge of the manufacturer. Such an embodiment in which deformation is applied is also included in the scope of the present invention.

The impurity diffusion composition of the present invention may be developed to a photovoltaic element such as a solar cell or a semiconductor element in which an impurity diffusion region is patterned on a semiconductor surface, such as a transistor array or a diode array. Photodiode array, transducer, and the like. [Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples. In addition, among the compounds used, the abbreviations are shown below.

γ-BL: γ-butyrolactone MMB: 3-methoxy-3-methyl-1-butanol.

(1) Solution viscosity and thixotropy The impurity composition of the impurity having a viscosity of less than 1,000 mPa·s is a rotary viscometer TVE-25L (E-type digital viscometer) manufactured by Toki Sangyo Co., Ltd., and the liquid temperature is measured at 25 ° C. The viscosity at 5 rpm. Further, the impurity diffusion composition having a viscosity of 1,000 mPa·s or more was a RVDV-11+P (B-type digital viscometer) manufactured by Brookfield, and the viscosity at a liquid temperature of 25 ° C and each number of revolutions was measured. The measured value at the number of revolutions. 5 rpm to the viscosity measured value will be transferred ₍₅₀ [eta]) in the number of 50 rpm at the measured value and the number of revolutions of ₅ rpm (η 5) ratio (η ₅ / η ₅₀₎ to Thixotropy.

(2) Measurement of wet gel size The imperfect diffusion composition was subjected to pressure filtration using a polytetrafluoroethylene (PTFE) membrane filter having a pore size of 0.1 μm using pressurized air (0.1 MPa). The solid matter remaining on the filter was observed by a digital microscope VHX-1000 (manufactured by Keyence Co., Ltd.), and the projected area of 50 gels was measured by image analysis, and the projection was calculated. The diameter of the circle having the same area is set to the wet gel size.

(3) Pattern accuracy The impurity diffusion composition was patterned into a stripe shape by screen printing, and the stripe width accuracy was confirmed.

The substrate was a semiconductor substrate containing n-type single crystal germanium of 156 mm on one side, and both surfaces were subjected to alkaline etching in order to remove slice damage or natural oxide. At this time, an infinite number of irregularities having a width of 40 μm to 100 μm and a depth of about 3 μm to 4 μm are formed on both surfaces of the semiconductor substrate as a coated substrate.

Using a screen printing machine (TM-750 manufactured by Micro-Tec Co., Ltd.), the screen mask was formed using 175 openings of 200 μm in width and 200 μm in length and 13.5 cm in length. The company (manufactured by SUS Co., Ltd., 400 mesh, wire diameter 23 μm) formed a stripe pattern.

After the impurity diffusion composition was screen-printed, the substrate was heated in air at 140 ° C for 5 minutes and further heated at 230 ° C for 30 minutes, thereby forming a thickness of about 1.5 μm, a width of about 210 μm, and a pitch of 600 μm. A pattern of 13.5 cm in length.

Here, the line width is measured every 10 points at equal intervals for any one line, and the standard deviation of the coating width is judged to be excellent (AA) within 12.5 μm, and it is judged that it is more than 12.5 μm and 15 μm or less. (A) is judged to be good (B) when it exceeds 15 μm and 17.5 μm, and is judged as pass (C) when it exceeds 17.5 μm and 20 μm, and is judged to be bad (D) when it exceeds 20 μm.

(4) The sheet resistance value was measured and cut into a 3 cm × 3 cm n-type silicon wafer (manufactured by Ferrotec Silicon Co., Ltd., surface resistivity 410 Ω / □) After immersing in a 1% hydrofluoric acid aqueous solution for 1 minute, it was washed with water, and after air blowing, it was treated at 140 ° C for 5 minutes using a hot plate.

The impurity-diffusion composition to be measured is applied to the tantalum wafer by a pre-bake film thickness of about 500 nm by a known spin coating method. After coating, the tantalum wafer was prebaked at 140 ° C for 5 minutes.

Then, each of the germanium wafers was placed in an electric furnace, and the impurities were thermally diffused at 900 ° C for 30 minutes in an atmosphere of nitrogen: oxygen = 99:1 (volume ratio). After the thermal diffusion, each of the tantalum wafers was immersed in a 5 wt% aqueous solution of hydrofluoric acid at 23 ° C for 1 minute to peel off the hardened diffusion composition. The p/n determination was performed using a p/n judging machine, and the surface resistance was measured using a four-probe surface resistance measuring apparatus RT-70V (manufactured by Napson Co., Ltd.). Sheet resistance value. The sheet resistance value is an indicator of the diffusibility of the impurity, and the small resistance value indicates that the amount of diffusion of the impurity is large.

(5) Diffusion uniformity The surface concentration distribution of the impurity was measured using a secondary ion mass spectrometer IMS7f (manufactured by Camera Co., Ltd.) for the diffused tantalum wafer used for the sheet resistance measurement. According to the obtained surface concentration distribution, the surface concentration of 10 points was read at intervals of 100 μm, and the ratio of the average to the standard deviation, that is, the "standard deviation / average" was calculated, and the "standard deviation / average" was determined to be 0.3 or less. In the case of (A), those who exceed 0.3 and 0.6 or less are judged to be good (B), those who exceed 0.6 and 1.0 are judged as pass (C), and those who exceed 1.0 are judged to be bad (D).

Example 1 (1) Synthesis of Polyoxane Solution To a 500 mL three-necked flask was added KBM-13 (methyltrimethoxydecane) 164.93 g (1.21 mol), KBM-103 (phenyltrimethoxydecane). 204.07 g (1.21 mol) and GBL 363.03 g, an aqueous phosphoric acid solution in which 0.125 g of phosphoric acid was dissolved in 130.76 g of water was added while stirring at 40 ° C for 30 minutes. After completion of the dropwise addition, the mixture was stirred at 40 ° C for 1 hour, and then heated to 70 ° C and stirred for 30 minutes. Thereafter, the oil bath was heated to 115 °C. The internal temperature of the solution reached 100 ° C 1 hour after the start of the temperature rise, and the mixture was heated and stirred for 1 hour from the temperature (the internal temperature was 100 ° C to 110 ° C). The obtained solution was cooled with an ice bath to obtain a polyoxyalkylene solution. The solid concentration of the polyoxyalkylene solution A was 39.8% by weight.

(2) Adjustment of wet gel solution To a 500 mL three-necked flask, 450 g of rosin alcohol as a dispersion medium and Aerosil RY200S as a dispersoid (manufactured by Aerosil Co., Ltd., number average particle diameter) were added. 16 nm) 50 g, stirred at room temperature for 1 hour. The obtained solution was poured into a three-roll mill EXAKT M-50I (manufactured by Yongsui Screen Printing Research Co., Ltd.), and dispersed at a roll speed ratio of 3.3:1.8:1 to pass it four times. Wet gel solution A was obtained.

(3) Preparation of Impurity Diffusion Composition 94 g of the synthesized polyaluminoxane solution, the adjusted wet gel solution A 103 g, phosphoric acid 34 g, PEO-1 (oxidized polyethylene) as a thickener A thickener, manufactured by Sumitomo Seika Co., Ltd., 30 g, γ-butyrolactone 189 g, and 50 g of pure water were mixed, and stirred sufficiently to become uniform, and the impurity diffusion composition A was obtained.

The viscosity and thixotropy of the obtained impurity diffusion composition A, and the wet gel size in the impurity diffusion composition A are the results shown in Table 2. Further, using the obtained impurity diffusion composition A, pattern accuracy, sheet resistance value, and diffusion uniformity were measured, and as a result, as shown in Table 2, both were good.

In order to remove the foreign matter in the impurity diffusion composition A, it was passed through a 50 μm polypropylene wound cartridge filter (manufactured by Advantec Toyo Co., Ltd.), and the result was Filtered in a blocked area.

Example 2 An impurity diffusion composition B was obtained in the same manner as in Example 1 except that the number of times of passing through the three-roll mill was changed to two. The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured, and the results were all as shown in Table 2.

In order to remove foreign matter in the impurity diffusion composition B, it was passed through a polypropylene wound filter cartridge (manufactured by Advantec Toyo Co., Ltd.) having a pore size of 50 μm, and as a result, filtration was carried out without clogging.

Example 3 An impurity diffusion composition C was obtained in the same manner as in Example 1 except that DYNO-MILL KD-6 (manufactured by Shinmaru Enterprises Co., Ltd.) was used instead of the three-roll mill. The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured, and the results were all as shown in Table 2.

In order to remove the foreign matter in the impurity diffusion composition C, it was passed through a polypropylene wound filter element (manufactured by Advantec Toyo Co., Ltd.) having a pore size of 50 μm, and as a result, filtration was carried out without clogging.

Example 4 An impurity diffusion composition D was obtained in the same manner as in Example 3 except that KC-7000 (acrylic thickener, manufactured by Kyoeisha Chemical Co., Ltd.) was used instead of PEO-1 as a thickener. . The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured, and the results were all as shown in Table 2.

In order to remove the foreign matter in the impurity diffusion composition D, it was passed through a polypropylene wound filter element (manufactured by Advantec Toyo Co., Ltd.) having a pore size of 50 μm, and as a result, filtration was carried out without clogging.

Example 5 An impurity diffusion composition E was obtained in the same manner as in Example 3 except that Ethocel 100cP (cellulose derivative, manufactured by Dow Chemical Co., Ltd.) was used instead of PEO-1 as a thickener. The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured, and the results were all as shown in Table 2.

In order to remove the foreign matter in the impurity diffusion composition E, it was passed through a polypropylene wound filter element (manufactured by Advantec Toyo Co., Ltd.) having a pore size of 50 μm, and as a result, filtration was carried out without clogging.

Example 6 50 g of MMB as a dispersion medium and 50 g of Flownon EC121 (manufactured by Kyoeisha Chemical Co., Ltd.) as a dispersion medium were added to a 500 mL three-necked flask, and the mixture was stirred at room temperature for 1 hour. The obtained solution was poured into a three-roll mill EXAKT M-50I (manufactured by Yongsui Screen Printing Research Co., Ltd.), and dispersed at a roll speed ratio of 3.3:1.8:1 to pass it four times. A moist gel solution B was obtained. Next, 94 g of a polyoxyalkylene solution, the adjusted wet gel solution B 50 g, 34 g of phosphoric acid, PEO-1 (manufactured by Sumitomo Seika Co., Ltd.) 30 g, γ-butyrolactone 242 g, 50 g of pure water was mixed, stirred well to become uniform, and the impurity-diffusing composition F was obtained.

The viscosity and thixotropy of the obtained impurity diffusion composition F and the wet gel size in the impurity diffusion composition F are the results shown in Table 2. Further, using the obtained impurity diffusion composition F, pattern accuracy, sheet resistance value, and diffusion uniformity were measured, and as a result, as shown in Table 2, both were good.

In order to remove the foreign matter in the impurity diffusion composition E, it was passed through a polypropylene wound filter element (manufactured by Advantec Toyo Co., Ltd.) having a pore size of 50 μm, and as a result, filtration was carried out without clogging.

Embodiment 7 A method for forming an n-type impurity diffusion layer and a p-type impurity diffusion layer is as shown in FIG. 5(a) by a screen printing method on an n-type germanium wafer 51 (Ferrotec Silicon Co., Ltd.) The n-type impurity diffusion composition 52 described in Example 1 was applied to a part of the surface resistivity of 410 Ω/□. After coating, the n-type germanium wafer 51 was prebaked at 140 ° C for 5 minutes.

Thereafter, the n-type germanium wafer 51 is placed in an electric furnace, and maintained at 900 ° C for 30 minutes in an atmosphere of nitrogen: oxygen = 99:1 to diffuse impurities in the n-type impurity diffusion composition 52 to the n-type. As the germanium wafer 51, as shown in FIG. 5(b), an n-type impurity diffusion layer 53 is formed.

Then, as shown in FIG. 5(c), a p-type impurity diffusion composition 54 (PBF, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the n-type germanium wafer 51 by spin coating. The whole surface was prebaked for 10 minutes at 200 ° C using a hot plate. Thereafter, the n-type germanium wafer 51 is placed in an electric furnace, and maintained at 600 ° C for 30 minutes in an oxygen atmosphere, and then maintained at 900 ° C for 30 minutes in a nitrogen atmosphere to thermally diffuse impurities, as shown in FIG. As shown in (d), a p-type impurity diffusion layer 55 is formed.

After the thermal diffusion, the n-type germanium wafer 51 was immersed in a 10% by weight aqueous solution of hydrofluoric acid at 23 ° C for 1 minute to peel off the n-type impurity diffusion composition 52 and the p-type impurity diffusion composition 54. The surface resistance of the n-type tantalum wafer 51 after peeling was measured using a four-probe surface resistance measuring apparatus RT-70V (manufactured by Napson Co., Ltd.). Regarding the sheet resistance value, the portion where the n-type impurity diffusion composition 52 was applied was 24 Ω/□ (p/n was judged as n), and the portion where only the p-type impurity diffusion composition 54 was applied was 87 Ω/□ ( It was confirmed that p/n was p), and it was confirmed that the n-type and p-type impurity diffusion layers were formed.

Embodiment 8 A method for forming an n-type impurity diffusion layer and a p-type impurity diffusion layer is as shown in FIG. 6(a), by screen printing on an n-type germanium wafer 61 (Ferrotec Silicon Co., Ltd.) The n-type impurity diffusion composition 62 described in Example 1 was applied to a part of the surface resistivity of 410 Ω/□. After coating, the n-type germanium wafer 61 was prebaked at 100 ° C for 5 minutes.

Thereafter, the p-type germanium wafer 61 was placed in an electric furnace, and maintained at 700 ° C for 30 minutes in an air atmosphere, and the n-type impurity diffusion composition 62 was fired.

Then, as shown in FIG. 6(b), a p-type impurity diffusion composition 64 (PBF, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the n-type germanium wafer 61 by spin coating. The whole surface was prebaked for 10 minutes at 200 ° C using a hot plate. Thereafter, the n-type germanium wafer 61 is placed in an electric furnace, and maintained at 600 ° C for 30 minutes in an oxygen atmosphere, and then maintained at 900 ° C for 30 minutes in a nitrogen atmosphere to thermally diffuse the impurity diffusion component, such as As shown in FIG. 6(c), an n-type impurity diffusion layer 63 and a p-type impurity diffusion layer 65 are formed.

After the thermal diffusion, the n-type germanium wafer 61 was immersed in a 10% by weight aqueous solution of hydrofluoric acid at 23 ° C for 1 minute to peel off the n-type impurity diffusion composition 62 and the p-type impurity diffusion composition 64. The surface resistance of the n-type tantalum wafer 61 after peeling was measured using a four-probe surface resistance measuring apparatus RT-70V (manufactured by Napson Co., Ltd.). Regarding the sheet resistance value, the portion to which the n-type impurity diffusion composition was applied was 34 Ω/□ (p/n was judged as n), and the portion where only the p-type impurity diffusion composition 64 was applied was 85 Ω/□ (p) /n was judged to be p), and it was confirmed that the n-type and p-type impurity diffusion layers were formed.

Comparative Example 1 An impurity diffusion composition G was obtained in the same manner as in Example 1 except that the dispersion by a three-roll mill was not carried out. The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured. As a result, as shown in Table 2, the pattern accuracy and the uniformity of diffusion were poor.

In addition, in order to remove the foreign matter in the impurity diffusion composition G, it was passed through a polypropylene wound filter element having a pore size of 50 μm (manufactured by Advantec Toyo Co., Ltd.), and as a result, the filter was clogged and could not be obtained. filter.

Comparative Example 2 An impurity diffusion composition H was obtained in the same manner as in Example 1 except that a planetary mixer was used instead of the three-roll mill. The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured. As a result, as shown in Table 2, the pattern accuracy and the uniformity of diffusion were poor.

In addition, in order to remove foreign matter in the impurity diffusion composition H, it was passed through a polypropylene wound filter element (manufactured by Advantec Toyo Co., Ltd.) having a pore size of 50 μm, and as a result, the filter was clogged and could not be obtained. filter.

Comparative Example 3 An impurity diffusion composition I was obtained in the same manner as in Example 1 except that a three-roll mill was used instead of the autorotation/revolution mixer (AR-100 manufactured by Shinky). The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured. As a result, as shown in Table 2, the pattern accuracy and the uniformity of diffusion were poor.

In addition, in order to remove the foreign matter in the impurity diffusion composition I, it was passed through a polypropylene wound filter element having a pore size of 50 μm (manufactured by Advantec Toyo Co., Ltd.), and as a result, the filter was clogged and could not be obtained. filter.

Comparative Example 4 An impurity diffusion composition J was obtained in the same manner as in Example 1 except that a roll mill RM-005M (manufactured by Asada Iron Works Co., Ltd.) was used instead of the three-roll mill. The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured. As a result, as shown in Table 2, the pattern accuracy and the uniformity of diffusion were poor.

In addition, in order to remove foreign matter in the impurity diffusion composition J, it was passed through a polypropylene wound filter element (manufactured by Advantec Toyo Co., Ltd.) having a pore size of 50 μm, and as a result, the filter was clogged and could not be obtained. filter.

Comparative Example 5 An impurity diffusion composition K was obtained in the same manner as in Example 1 except that the wet gel was not used. The pattern accuracy, the sheet resistance value, and the diffusion uniformity were measured. As a result, as shown in Table 2, the pattern accuracy was greatly deteriorated.

[Table 1]

[Table 2]

1‧‧‧Semiconductor substrate
2, 52, 62‧‧‧n type impurity diffusion composition
3, 53, 63‧‧‧n type impurity diffusion layer
4, 54, 64‧‧‧p type impurity diffusion composition
5, 55, 65‧‧‧p type impurity diffusion layer
6‧‧‧Protective film
6a‧‧‧ Protective film opening
7‧‧‧n type contact electrode
8‧‧‧p type contact electrode
9‧‧‧Back junction solar cells
51, 61‧‧‧n type silicon wafer

1(a) to 1(e) are process cross-sectional views showing an example of a method of forming an impurity diffusion layer using the impurity diffusion composition of the present invention. 2(f) to 2(h) are cross-sectional views showing an example of a method of producing a back junction type solar cell using the impurity diffusion composition of the present invention. 3(a) to 3(d) are cross-sectional views showing the steps of another example of the method of forming the impurity diffusion layer using the impurity diffusion composition of the present invention. 4(a) to 4(d) are cross-sectional views showing the steps of another example of the method of forming the impurity diffusion layer using the impurity diffusion composition of the present invention. 5(a) to 5(d) are cross-sectional views showing the steps of the method of forming the impurity diffusion layer shown in the seventh embodiment of the present invention. 6(a) to 6(c) are cross-sectional views showing the steps of a method of forming an impurity diffusion layer shown in Example 8 of the present invention.

no

Claims (13)

An impurity diffusion composition comprising (A) a wet gel having a size of 1 μm or more and 50 μm or less and (B) an impurity diffusion component. As herein patentable scope of an impurity diffusion, composition, its viscosity at a rotation number of 50 rpm of (η ₅₀₎ with a viscosity in the revolution speed 5 rpm of (η ₅₎ ratio (η ₅ / η ₅₀₎ It is 1.5 or more and less than 5.0. The impurity diffusion composition according to claim 1 or 2, wherein the (A) wet gel contains inorganic particles. The impurity diffusion composition according to claim 3, wherein the inorganic particles comprise cerium oxide. The impurity diffusion composition according to any one of claims 1 to 4, further comprising (C) polyoxyalkylene. The impurity diffusion composition according to claim 5, wherein the (C) polyoxane is represented by the following general formula (1), [Chemical Formula 1] (wherein R ¹ represents an aryl group having 6 to 15 carbon atoms, and a plurality of R ^{1 's} may be the same or different; and R ³ represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 10 carbon atoms; R ³ may be the same or different, and R ² and R ^{4 each} represent a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a decyloxy group having 1 to 6 carbon atoms, and a plurality of R ² and R ⁴ may be respectively The same may be different; n and m represent the composition ratio (%) of the components in each bracket, and n+m=100, n:m=95:5 to 25:75). The impurity diffusion composition according to any one of claims 1 to 6, further comprising (D) a thickener. The impurity diffusion composition of claim 7, wherein the (D) thickener comprises a cellulose derivative. A method of manufacturing a semiconductor device, comprising: a step of forming an impurity diffusion composition film by using the impurity diffusion composition according to any one of claims 1 to 8 on a semiconductor substrate; and forming an impurity A step of forming an impurity diffusion layer from the diffusion of the impurity diffusion composition film. The method of manufacturing a semiconductor device according to claim 9, wherein the printing is screen printing. The method for producing a semiconductor device according to claim 9 or claim 10, comprising: using the impurity diffusion composition film as a mask layer to print impurity diffusion including a second impurity different from the impurity A step of forming a second impurity diffusion composition film by the composition. A method of producing a semiconductor device, comprising: a step of forming a first impurity diffusion composition film by printing an impurity diffusion composition according to any one of claims 1 to 8 on a semiconductor substrate; printing a step of forming a second impurity diffusion composition film including the impurity diffusion composition of the second impurity; and forming the first film by heating the first impurity diffusion composition film and the second impurity diffusion composition film simultaneously The step of the impurity diffusion layer and the second impurity diffusion layer. A solar cell comprising a semiconductor element obtained by the production method according to any one of the items 9 to 12 of the patent application.