CN104471715A - Composition for forming passivation layer, semiconductor substrate with passivation layer and manufacturing method thereof, solar cell element and manufacturing method thereof, and solar cell - Google Patents

Abstract

The composition for forming a passivation layer of the present invention comprises an organoaluminum compound represented by the following general formula and at least one alkoxide compound selected from titanium alkoxides, zirconium alkoxides, and silicon alkoxides. In the following general formula , R¹Each independently represents an alkyl group having 1 to 8 carbon atoms; n represents an integer of 0 to 3; x²And X³Each independently represents an oxygen atom or a methylene group; r²、R³And R⁴Each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

Description

Composition for forming passivation layer, semiconductor substrate with passivation layer and manufacturing method thereof, solar cell element and manufacturing method thereof, and solar cell

technical field

The present invention relates to a composition for forming a passivation layer, a semiconductor substrate with a passivation layer, its manufacturing method, a solar cell element, its manufacturing method, and a solar cell.

Background technique

The manufacturing process of the conventional silicon solar cell element is demonstrated.

First, in order to enhance the light trapping effect and achieve high efficiency, a p-type silicon substrate with _a textured structure formed on the light-receiving surface side was prepared, and then the °C to 900 °C for tens of minutes to form an n-type diffused layer uniformly.

In this conventional method, since phosphorus is diffused using a mixed gas, an n-type diffused layer is formed not only on the surface of the light-receiving surface but also on the side and rear surfaces. Therefore, side etching is performed to remove the n-type diffusion layer formed on the side surface. In addition, the n-type diffused layer formed on the rear surface needs to be converted into a p ⁺ -type diffused layer. Therefore, an aluminum electrode is formed by applying an aluminum paste containing aluminum powder and a binder on the entire back surface and heat-treating (firing), thereby making the n-type diffusion layer a p ⁺ -type diffusion layer and simultaneously obtaining an ohmic contact .

However, an aluminum electrode formed from an aluminum paste has low electrical conductivity. Therefore, in order to reduce the sheet resistance, the aluminum electrode generally formed on the entire rear surface must have a thickness of about 10 μm to 20 μm after heat treatment (firing). Furthermore, since the thermal expansion coefficients of silicon and aluminum are very different, large internal stresses are generated in the silicon substrate on which the aluminum electrodes are formed during the heat treatment (firing) and cooling process, resulting in grain boundary damage. , crystalline defect growth and warpage.

In order to solve this problem, there is a method of reducing the coating amount of the aluminum paste to reduce the thickness of the back electrode layer. However, if the coating amount of the aluminum paste is reduced, the amount of aluminum diffused from the surface of the p-type silicon semiconductor substrate to the inside becomes insufficient. As a result, the required BSF (Back Surface Field) effect (the effect of improving the collection efficiency of generated carriers due to the presence of the p ⁺ -type diffusion layer) cannot be realized, so that the problem of lowering the characteristics of the solar cell arises.

Based on the above circumstances, a method of locally forming a point contact between a p ⁺ -type diffusion layer and an aluminum electrode by applying an aluminum paste to a part of the surface of a silicon substrate has been proposed (for example, refer to Japanese Patent No. 3107287).

In the case of such a solar cell having a point contact structure on the side opposite to the light-receiving surface (hereinafter also referred to as "back side"), it is necessary to suppress the recombination speed of minority carriers on the surface other than the aluminum electrode. . As a passivation layer for the rear side (hereinafter also simply referred to as a "passivation layer") used for this purpose, a SiO ₂ film or the like has been proposed (for example, refer to JP-A-2004-6565). The passivation effect due to the formation of such an oxide film includes an effect of reducing the density of surface levels that cause recombination by blocking unbonded bonds of silicon atoms in the back surface layer of the silicon substrate.

In addition, as another method of suppressing recombination of minority carriers, there is a method of reducing the density of minority carriers by using an electric field generated by fixed charges in the passivation layer. Such a passivation effect is generally called an electric field effect, and an aluminum oxide (Al ₂ O ₃ ) film or the like has been proposed as a material having a negative fixed charge (see, for example, Japanese Patent No. 4767110).

Such a passivation layer is usually formed by methods such as ALD (Atomic Layer Deposition, atomic layer deposition) or CVD (Chemical Vapor Depositon, chemical vapor deposition) (for example, refer to Journal of Applied Physics, 104 (2008), 113703-1～ 113703-7.). In addition, as a simple method of forming an aluminum oxide film on a semiconductor substrate, a method using a sol-gel method has been proposed (for example, refer to Thin Solid Films, 517 (2009), 6327-6330 and Chinese Physics Letters, 26 (2009), 088102-1～088102-4.).

On the other hand, if a layer with a large refractive index and a large passivation effect is formed on the light-receiving surface side of the silicon substrate, the improvement of the light trapping effect and the recombination speed of minority carriers can be suppressed, and the power generation of the solar cell can be improved. efficiency. For example, a method of increasing the refractive index of the film by forming an oxide film obtained by combining metals such as titanium and aluminum by a sol-gel method has been proposed (for example, refer to Japanese Journal of Applied Physics, 45 (2006), 5894-5901.).

Contents of the invention

The problem to be solved by the invention

The methods described in Journal of Applied Physics, 104 (2008), 113703-1 to 113703-7. include complicated manufacturing steps such as vapor deposition, and therefore it may be difficult to increase productivity. In addition, in the passivation layer forming composition used for the method described in Thin Solid Films, 517 (2009), 6327-6330. and Chinese Physics Letters, 26 (2009), 088102-1-088102-4. Defects such as gelation may occur over time, and the storage stability cannot be said to be sufficient. Furthermore, for the passivation layer obtained by the method described in Japanese Journal of Applied Physics, 45 (2006), 5894-5901., its refractive index is also difficult to be called sufficiently large, and there is a photocatalytic effect originating from titanium oxide. There is concern about the effect, and damage may be imparted to the sealing resin of the solar cell element.

This invention is made|formed in view of the above conventional problem, and the subject is to provide the composition for passivation layer forming which can form the passivation layer with a sufficiently large refractive index of a desired shape by a simple method, and is excellent in storage stability. Furthermore, the object of the present invention is to provide a semiconductor substrate with a passivation layer having a passivation layer having a sufficiently large refractive index obtained using the composition for forming a passivation layer, and a method for manufacturing the same, a solar cell element, and a method for manufacturing the same. , and solar cells.

means to solve the problem

Specific means for solving the above-mentioned problems are as follows.

<1> A passivation layer forming composition comprising an organoaluminum compound represented by the following general formula (I) and at least one alkoxide selected from titanium alkoxides, zirconium alkoxides, and silicon alkoxides compound.

【Chemical 1】

[In general formula (I), R ¹ each independently represents an alkyl group having 1 to 8 carbon atoms. n represents an integer of 0-3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbons. ]

<2> The composition for passivation layer formation as described in <1> which contains niobium alkoxide further.

<3> The composition for forming a passivation layer according to <2>, wherein the niobium alkoxide is at least A sort of.

<4> The composition for forming a passivation layer according to any one of <1> to <3>, wherein the alkoxide compound contains at least the titanium alkoxide, and the titanium alkoxide is selected from titanium methoxide, Titanium ethoxide, titanium isopropoxide, titanium n-propoxide, titanium n-butoxide, titanium tert-butoxide, titanium isobutoxide, titanium diisopropoxybisacetylacetonate and tetrakis (2-ethyl-1-hexanol) at least one of titanium.

<5> The composition for forming a passivation layer according to any one of <1> to <4>, wherein the alkoxide compound contains at least the zirconium alkoxide, and the zirconium alkoxide is selected from the group consisting of zirconium alkoxide, At least one of zirconium isopropoxide, zirconium n-propoxide, zirconium n-butoxide, zirconium t-butoxide, zirconium acetylacetonate, zirconium trifluoroacetylacetonate and zirconium hexafluoroacetylacetonate.

<6> The composition for forming a passivation layer according to any one of <1> to <5>, wherein the alkoxide compound contains at least the silicon alkoxide, and the silicon alkoxide has the following general formula ( II) Silicon alkoxides shown.

(R ⁵ O) _(4-m) SiR ⁶ _m (II)

[In the general formula (II), R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 8 carbon atoms. m represents an integer of 0-3. ]

<7> The composition for passivation layer formation in any one of <1>-<6> which contains resin further.

<8> The composition for passivation layer formation in any one of <1>-<7> which contains the compound represented by following general formula (III) further.

【Chemical 2】

<9> A semiconductor substrate with a passivation layer, which has a semiconductor substrate and a passivation layer provided on the entire surface or a part of the semiconductor substrate, and the passivation layer is any one of <1> to <8> The heat-processed thing of the composition for passivation layer forming of the item.

<10> A method for producing a semiconductor substrate with a passivation layer, comprising: imparting the composition for forming a passivation layer according to any one of <1> to <8> on the entire surface or a part of the semiconductor substrate and a step of forming a composition layer; and a step of heat-treating the composition layer to form a passivation layer.

<11> A solar cell element comprising: a semiconductor substrate in which a p-type layer and an n-type layer are pn-joined; a passivation layer provided on the entire surface or a part of the semiconductor substrate; A heat-treated product of the composition for forming a passivation layer according to any one of <1> to <8>; and one or more layers selected from the p-type layer and n-type layer arranged on the semiconductor substrate on the electrodes.

<12> A method of manufacturing a solar cell element, comprising: forming a p-n junction formed by joining a p-type layer and an n-type layer and including one or more selected from the p-type layer and the n-type layer. A step of applying the passivation layer-forming composition according to any one of <1> to <8> to at least a part of the surface of the semiconductor substrate having an electrode on the layer to form a composition layer; and The process of heat-treating the said composition layer and forming a passivation layer.

<13> A solar cell comprising the solar cell element according to <11> and a wiring material disposed on an electrode of the solar cell element.

Invention effect

According to this invention, the composition for passivation layer formation which can form the passivation layer which has a desired shape by a simple method and has a sufficiently large refractive index, and is excellent in storage stability can be provided. Furthermore, according to the present invention, a semiconductor substrate with a passivation layer having a passivation layer having a sufficiently large refractive index obtained using the composition for forming a passivation layer, a manufacturing method thereof, a solar cell element, and a manufacturing method thereof can also be provided. , and solar cells.

Description of drawings

FIG. 1( a ) to FIG. 1( d ) are cross-sectional views schematically showing an example of a method for manufacturing a solar cell element having a passivation layer according to one embodiment of the present invention.

FIG. 2( a ) to FIG. 2( e ) are cross-sectional views schematically showing another example of the method for manufacturing a solar cell element having a passivation layer according to one embodiment of the present invention.

3 is a cross-sectional view schematically showing a back electrode type solar cell element having a passivation layer according to an embodiment of the present invention.

Detailed ways

In this specification, the term "process" is not only an independent process, but also a case where it cannot be clearly distinguished from other processes. In this case, as long as the purpose of the process can be achieved, it is also included in this term. In addition, the numerical range shown using "-" shows the range which includes the numerical value described before and after "-" as a minimum value and a maximum value, respectively. Furthermore, the content of each component in the composition refers to the total amount of the plurality of substances present in the composition, unless otherwise specified, when a plurality of substances corresponding to each component exist in the composition. . In addition, the term "layer" in this specification includes not only the configuration formed in the shape of the entire surface when viewed in plan view, but also the configuration formed in the shape of a part when viewed in plan view.

<Composition for Passivation Layer Formation>

The passivation layer forming composition of the present invention comprises an organoaluminum compound represented by the following general formula (I) (hereinafter also referred to as "specific organoaluminum compound") and At least one alkoxide compound in silicon (hereinafter also referred to as "specific alkoxide compound"). The said composition for passivation layer forming may contain other components as needed. By making the composition for passivation layer forming contain a specific organoaluminum compound and a specific alkoxide compound, the passivation layer which has a desired shape and has a sufficiently large refractive index can be formed with a simple method. Moreover, the storage stability of this composition for passivation layer forming is excellent.

【Chemical 3】

In the general formula (I), R ¹ each independently represent an alkyl group having 1 to 8 carbon atoms. n represents an integer of 0-3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbons. Here, when there is a plurality of any one of R ¹ , R ² , R ³ , R ⁴ , X ² and X ³ , the plurality of groups represented by the same symbol may be the same or different.

Provide a passivation layer-forming composition containing a specific organoaluminum compound and a specific alkoxide compound on a semiconductor substrate to form a composition layer of a desired shape, and heat-treat (fire) it, whereby the A passivation layer having an excellent passivation effect and having a sufficiently large refractive index is formed in a desired shape. The method of the present invention is a simple and highly productive method that does not require a vapor deposition device or the like. Furthermore, the passivation layer of a desired shape can be formed without requiring complicated processes, such as a mask process. Moreover, since the said composition for passivation layer formation contains a specific organoaluminum compound and a specific alkoxide compound, generation|occurrence|production of troubles, such as gelation, is suppressed over time, and it is excellent in storage stability.

In this description, using devices such as WT-2000PVN (Japan Shimei Lebo Co., Ltd.), the effective lifetime of the minority carriers in the semiconductor substrate formed with the passivation layer is measured by the microwave reflection photoconductivity attenuation method. This can evaluate the passivation effect of the semiconductor substrate.

Here, the effective lifetime τ can be represented by the bulk lifetime τ _b inside the semiconductor substrate and the surface lifetime τ _s on the surface of the semiconductor substrate as in the following equation (A). When the surface level density on the surface of the semiconductor substrate is small, τ _s becomes longer, and as a result, the effective lifetime τ becomes longer. In addition, even if defects such as dangling bonds inside the semiconductor substrate are reduced, the bulk lifetime τ _b becomes longer, and the effective lifetime τ also becomes longer. That is, the interface characteristics between the passivation layer and the semiconductor substrate and internal characteristics of the semiconductor substrate such as dangling bonds can be evaluated by measuring the effective lifetime τ.

1/τ＝1/τ _b +1/τ _s (A)

In addition, the longer the effective lifetime, the slower the recombination speed of minority carriers. In addition, the conversion efficiency can be improved by constituting the solar cell element using a semiconductor substrate with a long effective life.

(specific organoaluminum compounds)

The said composition for passivation layer formation contains at least 1 sort(s) of organoaluminum compounds represented by the said General formula (I) (it is also called a "specific organoaluminum compound" hereafter). The organoaluminum compound includes compounds called aluminum alkoxides, aluminum chelates, and the like, and preferably has an aluminum chelate structure in addition to the aluminum alkoxide structure. In addition, as described in Nippon Seramikkusu Kyokai Gakujitsu Ronbunshi, 97 (1989) 369-399, a specific organoaluminum compound is converted into alumina (Al ₂ O ₃ ) by heat treatment (firing).

The inventors of the present invention think as follows about the reason why the composition for passivation layer forming can form the passivation layer which has the excellent passivation effect by containing the organoaluminum compound represented by General formula (I).

It is considered that the aluminum oxide formed by heat-treating (firing) the composition for forming a passivation layer containing a specific organoaluminum compound and a specific alkoxide compound tends to be in an amorphous state, and therefore tends to form an amorphous state at the interface with the semiconductor substrate. A 4-coordinated alumina layer is formed nearby, and may have a large negative fixed charge due to 4-coordinated alumina. And it is believed that: the larger negative fixed charges generate an electric field near the interface of the semiconductor substrate, thereby reducing the concentration of minority carriers, and as a result, the recombination speed of carriers on the interface is suppressed, so that an excellent passivation can be formed. The passivation layer of the effect. Furthermore, it is considered that the refractive index of the passivation layer formed becomes large by further containing a specific alkoxide compound in addition to an organoaluminum compound.

Here, the state of the 4-coordinated alumina layer on the surface of the semiconductor substrate, which is the cause of the negative fixed charge, can be confirmed by using electron energy dissipation capability using a scanning transmission electron microscope (STEM, Scanning Transmission electron Microscope). Spectroscopy (EELS, Electron Energy Loss Spectroscopy) analysis, cross-sectional investigation of semiconductor substrates and combination methods. 4-coordinated alumina is considered to have a structure in which the center of silica (SiO ₂ ) is isomorphously replaced by silicon (isomorphous substitution), and forms a negative charge at the interface of silica and alumina like zeolite and clay. source.

In addition, the state of the formed alumina can be confirmed by measuring an X-ray diffraction pattern (XRD, X-ray diffraction). For example, an amorphous structure can be confirmed because XRD does not show a specific reflection pattern. In addition, the negative fixed charge that alumina has can be evaluated by a CV method (Capacitance Voltage measurement, capacitance voltage measurement method). However, the value of the surface level density obtained by the CV method may be larger than the aluminum oxide layer formed by ALD or CVD method about the heat treatment layer of the aluminum oxide formed from the composition for passivation layer forming of this invention. However, the passivation layer formed from the passivation layer-forming composition of the present invention has a large electric field effect, reduces the concentration of minority carriers, and lengthens the surface lifetime τ _s . Therefore, the surface level density is relatively unproblematic.

In the general formula (I), R ¹ each independently represent an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by R ¹ may be linear or branched. As the alkyl group represented by ^R , specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, hexyl, octyl, 2- Ethylhexyl, 3-ethylhexyl, etc. Among them, the alkyl group represented by R ¹ is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, more preferably an unsubstituted alkyl group having 1 to 4 carbon atoms, from the viewpoint of storage stability and passivation effect.

In general formula (I), n represents the integer of 0-3. n is preferably an integer of 1-3, more preferably 1 or 3, from the viewpoint of storage stability. In addition, X ² and X ³ each independently represent an oxygen atom or a methylene group. From the viewpoint of storage stability, at least one of ^X2 and ^X3 is preferably an oxygen atom.

R ² , R ³ and R ⁴ in the general formula (I) each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. The alkyl groups represented by R ² , R ³ and R ⁴ may be linear or branched. The alkyl group represented by R ² , R ³ and R ⁴ may have a substituent or may be an unsubstituted alkyl group, and is preferably an unsubstituted alkyl group. The alkyl group represented by R ² , R ³ and R ⁴ is an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by R ² , R ³ or R ⁴ is an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. Specifically, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, hexyl, octyl, 2-ethylhexyl, 3-ethylhexyl wait.

Among them, from the viewpoint of storage stability and passivation effect, it is preferable to make ^R2 and ^R3 in the general formula (I) each independently be a hydrogen atom or an unsubstituted alkyl group with 1 to 8 carbon atoms, more preferably A hydrogen atom or an unsubstituted alkyl group having 1 to 4 carbon atoms.

In addition, from the viewpoint of storage stability and passivation effect, R in the general formula (I) is preferably a hydrogen atom or an unsubstituted alkyl group ^with 1 to 8 carbons, more preferably a hydrogen atom or an unsubstituted alkyl group with 1 to 8 carbons. 4 unsubstituted alkyl.

From the viewpoint of storage stability, the organoaluminum compound represented by the general formula (I) is preferably a compound in which n is 1 to 3 and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbons.

From the standpoint of storage stability and passivation effect, the organoaluminum compound represented by the general formula (I) is preferably selected from compounds where n is 0 and ^R is independently an alkyl group with 1 to 4 carbon atoms and n is an integer of 1 to 3, ^R1 is each independently an alkyl group with 1 to 4 carbons, at least one of ^X2 and ^X3 is an oxygen atom, ^R2 and ^R3 are each independently a hydrogen atom or a carbon number 1 ~4 alkyl groups and ^R4 are each independently at least one of a hydrogen atom or an alkyl group having 1 to 4 carbons.

The organoaluminum compound represented by the general formula (I) is more preferably selected from compounds in which n is 0 and ^R is independently an unsubstituted alkyl group with 1 to 4 carbons, and n is an integer of 1 to 3, R ¹ each independently is an unsubstituted alkyl group having 1 to 4 carbon atoms, at least one of ^X2 and ^X3 is an oxygen atom, and ^R2 or ^R3 bonded to the oxygen atom is an alkyl group having 1 to 4 carbon atoms And when X ² or X ³ is a methylene group, at least one of the compounds in which R ² or R ³ bonded to the methylene group is a hydrogen atom and R ⁴ is a hydrogen atom.

Specific organoaluminum compounds (aluminum trialkoxide) in which n is 0 in the general formula (I) include aluminum trimethoxide, aluminum triethoxide, aluminum triisopropoxide, aluminum tri-sec-butoxide, Mono-sec-butoxy aluminum diisopropoxide, aluminum tri-tert-butoxide, aluminum tri-n-butoxide, etc.

In addition, as the specific organoaluminum compound represented by the general formula (I), n is an integer of 1 to 3, specifically, ethyl acetoacetate diisopropoxide aluminum, methyl acetoacetate diisopropoxide Aluminum, aluminum tris(ethylacetoacetate), aluminum bis(ethylacetoacetate) monoacetylacetonate, aluminum tris(acetylacetonate), and the like.

In addition, as the specific organoaluminum compound in which n in the general formula (I) is an integer of 1 to 3, a prepared organoaluminum compound or a commercially available one may be used. Examples of commercially available products include ALCH, ALCH-50F, ALCH-75, ALCH-TR, ALCH-TR-20, Alumichelate M, Alumichelate D, and Alumichelate A(W), which are trade names of Kawaken Fine Chemicals Co., Ltd. wait.

In addition, the specific organoaluminum compound in which n in the general formula (I) is an integer of 1 to 3 can be produced by mixing the above-mentioned aluminum trialkoxide and the above-mentioned compound having a specific structure having two carbonyl groups. In addition, commercially available aluminum chelate compounds can also be used.

When the aluminum trialkoxide and the compound having the specific structure are mixed, at least a part of the alkanol groups of the aluminum trialkoxide is substituted with the compound of the specific structure to form an aluminum chelate structure. At this time, a solvent may be present as needed, and heat treatment, addition of a catalyst, and the like may be performed. By substituting at least a part of the aluminum alkoxide structure with an aluminum chelate structure, while improving the stability of a specific organoaluminum compound with respect to hydrolysis and a polymerization reaction, the storage stability of the composition for passivation layer formation is further improved. In addition, the closer the reactivity is to the niobium alkoxide, titanium alkoxide, zirconium alkoxide, and silicon alkoxide described later, the easier it is to form a composite oxide that is dense, has a small photocatalytic effect, and has a large refractive index.

The compound having a specific structure having two carbonyl groups is preferably at least one selected from the group consisting of β-diketone compounds, β-ketoester compounds, and malonate diesters from the viewpoint of reactivity and storage stability. Specific examples of compounds having a specific structure having two carbonyl groups include: acetylacetone, 3-methyl-2,4-pentanedione, 2,3-pentanedione, 3-ethyl-2, 4-pentanedione, 3-butyl-2,4-pentanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 2,6-dimethyl-3,5 -Heptanedione, 6-methyl-2,4-heptanedione and other β-diketone compounds; methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, isobutyl acetoacetate, butyl acetoacetate, tert-butyl acetoacetate, amyl acetoacetate, isopentyl acetoacetate, hexyl acetoacetate, n-octyl acetoacetate, heptyl acetoacetate, 3-pentyl acetoacetate, ethyl 2-acetylheptanoate, -Butyl ethyl acetoacetate, 4,4-dimethyl-3-oxopentanoic acid ethyl ester, 4-methyl-3-oxopentanoic acid ethyl ester, 2-ethyl acetoacetate ethyl ester, hexyl acetyl Ethyl acetate, methyl 4-methyl-3-oxopentanoate, isopropyl acetoacetate, ethyl 3-oxohexanoate, ethyl 3-oxopentanoate, methyl 3-oxopentanoate , Methyl 3-oxohexanoate, ethyl 2-methylacetoacetate, ethyl 3-oxoheptanoate, methyl 3-oxohexanoate, 4,4-dimethyl-3-oxopentyl β-keto ester compounds such as methyl ester; dimethyl malonate, diethyl malonate, dipropyl malonate, diisopropyl malonate, dibutyl malonate, di tert-butyl ester, dihexyl malonate, tert-butyl ethyl malonate, diethyl methyl malonate, diethyl ethyl malonate, diethyl isopropyl malonate, butyl Diethyl malonate, diethyl sec-butylmalonate, diethyl isobutylmalonate, diethyl 1-methylbutylmalonate and other malonate diesters.

When the above-mentioned specific organoaluminum compound has an aluminum chelate structure, as long as the number of aluminum chelate structures is 1-3, it will not specifically limit. Among them, the number of aluminum chelate structures is preferably 1 or 3 from the viewpoint of storage stability, and the number of aluminum chelate structures is more preferably 1 from the viewpoint of solubility. The number of aluminum chelate structures can be controlled, for example, by appropriately adjusting the mixing ratio of the aluminum trialkoxide and the compound capable of forming a chelate with aluminum. In addition, a compound having a desired structure can also be appropriately selected from commercially available aluminum chelate compounds.

Among the organoaluminum compounds represented by the general formula (I), specifically, aluminum diisopropoxide ethylacetoacetate and At least one kind of aluminum triisopropoxide, more preferably aluminum diisopropoxide ethyl acetoacetate.

The existence of the aluminum chelate structure in the above-mentioned specific organoaluminum compound can be confirmed by a commonly used analysis method. For example, infrared spectroscopy, nuclear magnetic resonance spectroscopy, melting point, and the like can be used for confirmation.

The content rate of the said specific organoaluminum compound contained in the said composition for passivation layer forming can be selected suitably as needed. From the viewpoint of storage stability and passivation effect, the content of the organoaluminum compound in the composition for forming a passivation layer may be 1% by mass to 70% by mass, preferably 3% by mass to 60% by mass, more preferably It is 5 mass % - 50 mass %, More preferably, it is 10 mass % - 30 mass %.

The organoaluminum compound may be liquid or solid, and is not particularly limited. From the viewpoint of passivation effect and storage stability, it is preferable to use a specific organoaluminum compound that is stable at normal temperature (25° C.) and has good solubility or dispersibility in a solvent when a solvent is used. By using such a specific organoaluminum compound, there exists a tendency for the homogeneity of the passivation layer to be formed to be further improved, and a desired passivation effect to be acquired stably.

(specific alkoxide compounds)

The passivation layer-forming composition of the present invention further contains at least one alkoxide compound (hereinafter also referred to as "specific aluminum compound") selected from the group consisting of titanium alkoxide, zirconium alkoxide, and silicon alkoxide in addition to the specific organoaluminum compound. alkoxide compounds"). By containing at least one compound selected from specific alkoxide compounds, it is possible to produce a complex oxide having a large refractive index together with an organoaluminum compound, and to further enhance the passivation effect.

The refractive index of the passivation layer formed by heat-processing (baking) the composition for passivation layer formation of this invention becomes larger than the passivation layer formed only from an organoaluminum compound. For example, in a solar cell element in which a passivation layer having a large refractive index is formed on the light receiving surface, since the utilization efficiency of light is further improved, the power generation efficiency is improved. The refractive index of the passivation layer formed from the composition for passivation layer forming becomes like this. Preferably it is 1.4 or more, More preferably, it is 1.6 or more, More preferably, it is 1.6-2.5.

There are no particular limitations on the titanium alkoxide, and it can be appropriately selected from commonly used titanium alkoxides. Among them, titanium alkoxide is preferably reacted with the organoaluminum compound represented by the general formula (I) and composited to form a denser composite oxide from the viewpoint of making it difficult to decompose the resin in contact with the formed passivation layer. titanium alkoxides. Specific examples of the titanium alkoxide include titanium methoxide, titanium ethoxide, titanium isopropoxide, titanium n-propoxide, titanium n-butoxide, titanium tert-butoxide, titanium isobutoxide, and diisopropoxybisacetylacetone. Titanium, tetrakis(2-ethyl-1-hexanol)titanium, and the like. It is generally known that titanium oxide obtained by heat-treating (calcining) titanium alkoxide has a large refractive index. However, when titanium oxide itself is added to the composition for forming a passivation layer and used, the resin in contact with the passivation layer may be decomposed by sunlight or the like due to the photocatalytic action of titanium oxide. . On the other hand, when a titanium alkoxide is applied to the composition for forming a passivation layer, the titanium alkoxide forms a composite oxide together with an organoaluminum compound, which suppresses photocatalysis and can form a passivation layer with a large refractive index. layer.

The zirconium alkoxide is not particularly limited as long as it reacts with the organoaluminum compound represented by the general formula (I) to form a composite oxide. The zirconium alkoxide specifically includes zirconium ethoxide, zirconium isopropoxide, zirconium n-propoxide, zirconium n-butoxide, zirconium tert-butoxide, zirconium acetylacetonate, zirconium trifluoroacetylacetonate, zirconium hexafluoroacetylacetonate, etc. . It is generally known that zirconium oxide obtained by heat-treating (calcining) a zirconium alkoxide has a large refractive index. However, when zirconia itself is added to the composition for forming a passivation layer and used, resins in contact with the passivation layer may be decomposed by sunlight or the like due to the photocatalytic action of zirconia. . On the other hand, in the case where zirconium alkoxide is applied to the passivation layer forming composition, zirconium alkoxide forms a composite oxide together with the organoaluminum compound, which can suppress photocatalysis and form a passivation layer with a large refractive index. layer.

Silicon alkoxides will be described. Alumina formed by heat-treating (calcining) the composition for forming a passivation layer containing an organoaluminum compound represented by general formula (I) tends to be in an amorphous state, and partly generates tetracoordinate alumina. When 4-coordinated alumina is produced, a negative fixed charge is obtained. Here, if silicon alkoxide is contained in the composition for passivation layer formation, 4 coordinate silicon oxide will generate|occur|produce simultaneously by heat processing (baking). It is known that 4-coordinate silicon oxide substituted the central atom from silicon to aluminum by isomorphic substitution. Therefore, when 4-coordinated silicon oxide is formed in the alumina layer, 4-coordinated alumina having a negative fixed charge is correspondingly easily produced. Although the refractive index of silicon oxide itself obtained by heat-treating (calcining) silicon alkoxide is lower than that of alumina, it is easy to generate 4-coordinate alumina as a source of negative fixed charges by compounding, so it does not make the The use of silicon alkoxide to such an extent that the refractive index is greatly lowered results in a more excellent passivation effect.

As the silicon alkoxide, as long as it reacts with an organoaluminum compound represented by the general formula (I), a titanium alkoxide, a zirconium alkoxide, or a niobium alkoxide contained as needed to form a composite oxide, there are no silicon alkoxides. Special restrictions. Among them, the silicon alkoxide is preferably a compound represented by the following general formula (II).

(R ⁵ O) _(4-m) SiR ⁶ _m (II)

In formula (II), R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 8 carbon atoms. n represents an integer of 0-3. Here, when a plurality of any one of R ⁵ and R ⁶ exists, the plurality of R ⁵ or R ⁶ present may be the same or different, respectively.

Specific examples of the silicon alkoxide include silicon tetramethoxide, silicon tetraethoxide, and silicon tetrapropoxide.

Among the alkoxide compounds selected from titanium alkoxides, zirconium alkoxides and silicon alkoxides, it is preferable to use At least one selected from titanium alkoxide and zirconium alkoxide, more preferably at least one selected from titanium isopropoxide, zirconium ethoxide and zirconium isopropoxide, more preferably titanium isopropoxide and zirconium ethoxide at least one of the

In the passivation layer forming composition, the total content of specific alkoxide compounds selected from titanium alkoxides, zirconium alkoxides, and silicon alkoxides is preferably 0.5 mass % to 65 mass %, more preferably 1 % by mass to 65% by mass, more preferably 2% by mass to 60% by mass.

In addition, from the viewpoint of the refractive index of the composite oxide produced and the passivation effect, the ratio of the content of the above-mentioned specific alkoxide compound to the content of the organoaluminum compound represented by the general formula (I) (specific alkoxide compound/organoaluminum compound represented by the general formula (I)) is preferably 0.01-1000, more preferably 0.05-500, still more preferably 0.1-100.

(niobium alkoxide)

The composition for passivation layer formation may contain at least 1 sort(s) of niobium alkoxide. It is known that niobium oxide obtained by heat-treating (firing) niobium alkoxide has a large refractive index, so by heat-treating (firing) a composition for forming a passivation layer containing niobium alkoxide, the refractive index Larger passivation layer.

The niobium alkoxide is not particularly limited as long as it reacts with the organoaluminum compound represented by the general formula (I) to form a composite oxide. Specific examples of niobium alkoxide include niobium ethoxide, niobium isopropoxide, niobium n-propoxide, niobium n-butoxide, and niobium phenoxide.

When the composition for forming a passivation layer contains niobium alkoxide, the content of the niobium alkoxide is preferably 0.2% by mass to 50% by mass, more preferably 0.5% by mass, based on the total mass of the composition for forming a passivation layer ~48% by mass, more preferably 1% by mass to 46% by mass.

In addition, when the composition for forming a passivation layer contains niobium alkoxide, from the viewpoint of the refractive index of the complex oxide produced and the passivation effect, the content of the niobium alkoxide relative to that represented by the general formula (I) The content ratio of the organoaluminum compound (niobium alkoxide/organoaluminum compound represented by the general formula (I)) is preferably 0.01-1000, more preferably 0.05-500, even more preferably 0.1-100.

Furthermore, when the composition for passivation layer formation contains a niobium alkoxide, from the viewpoint of the refractive index of the composite oxide produced|generated and a passivation effect, the total content of a specific alkoxide compound and niobium alkoxide is relative to The ratio of the content of the organoaluminum compound represented by the general formula (I) is preferably 0.01-1000, more preferably 0.05-500, and even more preferably 0.1-100.

In the passivation layer forming composition, the total content of the organoaluminum compound represented by the general formula (I), the specific alkoxide compound, and optionally the niobium alkoxide contained in the passivation layer forming composition In mass, it is preferable that it is 1 mass % - 70 mass %, it is more preferable that it is 3 mass % - 60 mass %, and it is still more preferable that it is 5 mass % - 50 mass %.

(resin)

The composition for passivation layer formation may contain at least 1 sort(s) of resin further. By containing the resin, the shape stability of the composition layer formed by applying the above passivation layer forming composition on the semiconductor substrate is further improved, and it can be selectively formed in a desired shape in the region where the above composition layer is formed. passivation layer.

The kind of resin is not particularly limited. When providing the composition for passivation layer forming on a semiconductor substrate, it is preferable that resin can adjust viscosity to the range which can form a favorable pattern. As the resin, specifically, polyvinyl alcohol; polyacrylamides; polyvinylamides; polyvinylpyrrolidone; polyethylene oxides; polysulfonic acid; polyacrylamide alkylsulfonic acid; cellulose ; Cellulose derivatives such as carboxymethyl cellulose, carboxyethyl cellulose, ethyl cellulose and other cellulose ethers; gelatin and gelatin derivatives; starch and starch derivatives; sodium alginate and sodium alginate derivatives; Xanthan gum and xanthan gum derivatives; guar gum and guar gum derivatives; scleroglucan and scleroglucan derivatives; tragacanth and tragacanth derivatives; dextrin and dextrin derivatives; (Meth)acrylic resins; (meth)acrylate resins (such as alkyl (meth)acrylate resins, dimethylaminoethyl (meth)acrylate resins, etc.); butadiene resins, styrene resins, silicon Oxane resins, copolymers of these substances, and the like. These resins may be used alone or in combination of two or more.

Among these resins, it is preferable to use a neutral resin that does not have acidic and basic functional groups from the viewpoint of storage stability and pattern formation, and it is more preferable to use a neutral resin that can easily adjust viscosity and thixotropy even when the content is small. Preference is given to using cellulose derivatives.

Moreover, the molecular weight of these resins is not specifically limited, It is preferable to adjust suitably in view of the required viscosity of the composition for passivation layer forming. The weight average molecular weight of the resin is preferably 1,000 to 10,000,000, more preferably 3,000 to 5,000,000 from the viewpoints of storage stability and pattern formability. In addition, the weight average molecular weight of resin was calculated|required by converting the molecular weight distribution measured using GPC (gel permeation chromatography) using the calibration curve of standard polystyrene.

When the composition for passivation layer formation contains resin, the content rate in the composition for passivation layer formation of resin can be selected suitably as needed. For example, it is preferable that the content rate of resin is 0.1 mass % - 30 mass % in the gross mass of the composition for passivation layer forming. From the viewpoint of expressing thixotropy for easier pattern formation, the above content is more preferably 1% by mass to 25% by mass, still more preferably 1.5% by mass to 20% by mass, still more preferably 1.5% by mass to 10% by mass .

When the composition for passivation layer formation contains resin, the content ratio of the said organoaluminum compound in the said composition for passivation layer formation, and the said resin can be selected suitably as needed. Among them, from the viewpoint of pattern formation and storage stability, the content ratio of the resin to the organoaluminum compound (resin/organoaluminum compound) is preferably 0.001 to 1000, more preferably 0.01 to 100, and even more preferably 0.1 to 1. .

(high boiling point material)

In the composition for passivation layer formation, you may use a high boiling point material together with resin, or may use a high boiling point material as a material instead of resin. The high-boiling point material is preferably a compound that is easily vaporized when heated and does not require degreasing treatment. In addition, the high-boiling point material is particularly preferably a high-viscosity high-boiling point material capable of maintaining a printed shape after printing and coating. Examples of materials satisfying these conditions include isobornylcyclohexanol represented by the general formula (III).

【Chemical 4】

The isobornylcyclohexanol represented by the general formula (III) is commercially available "TerusolveMTPH" (NIPPON TERPENE CHEMICALS, INC., trade name). The boiling point of isobornyl cyclohexanol is as high as 308°C to 318°C, and when removing this isobornylcyclohexanol from the composition layer, degreasing treatment by heat treatment (calcination) is not performed like resin, and it is vaporized by heating. Melting will make it disappear. Therefore, in the drying step after applying the composition for forming a passivation layer on the semiconductor substrate, most of the solvent and isobornylcyclohexanol contained in the composition as needed can be removed, and heat treatment ( Black residue after firing).

When the composition for passivation layer formation contains a high boiling point material, the content rate of a high boiling point material is preferably 0.5 mass % - 85 mass % in the gross mass of the composition for passivation layer formation, More preferably, it is 1 mass % ~80% by mass, particularly preferably 2% by mass to 80% by mass.

(solvent)

The said composition for passivation layer forming may contain a solvent. By making the composition for passivation layer forming contain a solvent, it exists in the tendency which can adjust a viscosity more easily, improve provision property more, and can form a more uniform passivation layer. The above-mentioned solvent is not particularly limited, and can be appropriately selected as necessary. Among them, a solvent capable of forming a uniform solution by dissolving the organoaluminum compound represented by the general formula (I) and the specific alkoxide compound is preferable, and it is more preferable to contain at least one organic solvent.

As the solvent, specifically, acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, methyl N-hexyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetone ketone solvents such as methyl acetone; diethyl ether, methyl ethyl ether, methyl n-propyl ether, diisopropyl ether, tetrahydrofuran, methyl tetrahydrofuran, dioxane, dimethyldioxane, ethylene dioxane Alcohol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-propyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, Ethylene glycol methyl ethyl ether, diethylene glycol methyl n-propyl ether, diethylene glycol methyl n-butyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether , Diethylene glycol methyl n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl n-butyl ether, Triethylene glycol di-n-butyl ether, triethylene glycol methyl n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol Glycol methyl n-butyl ether, tetraethylene glycol di-n-butyl ether, tetraethylene glycol methyl n-hexyl ether, tetraethylene glycol di-n-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether , propylene glycol di-n-propyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol methyl n-butyl ether, dipropylene glycol di-n-propyl ether Dipropylene glycol di-n-butyl ether, dipropylene glycol methyl n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol methyl ethyl ether, tripropylene glycol methyl n-butyl ether, Tripropylene glycol di-n-butyl ether, tripropylene glycol methyl n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetrapropylene glycol methyl ethyl ether, tetrapropylene glycol methyl n-butyl ether, tetrapropylene glycol di Ether solvents such as n-butyl ether, tetrapropylene glycol methyl n-hexyl ether, tetrapropylene glycol di-n-butyl ether; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isoacetic acid Butyl ester, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, acetic acid 2-(2-Butoxyethoxy) ethyl ester, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol acetate Methyl ether ester, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol ethyl ether acetate, ethylene glycol diacetate, methoxytriethylene glycol acetate, propane Ethyl lactate, n-butyl propionate, isoamyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-pentyl lactate, ethylene glycol methyl Ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate , propylene glycol propyl ether acetate, γ-butyrolactone, γ-valerolactone and other ester solvents; acetonitrile, N-methylpyridine Rolidone, N-ethylpyrrolidone, N-propylpyrrolidone, N-butylpyrrolidone, N-hexylpyrrolidone, N-cyclohexylpyrrolidone, N,N-dimethylformamide, N,N-dimethyl Aprotic polar solvents such as acetamide and dimethyl sulfoxide; dichloromethane, chloroform, dichloroethane, benzene, toluene, xylene, hexane, octane, ethylbenzene, 2-ethylhexanoic acid , methyl isobutyl ketone, methyl ethyl ketone and other hydrophobic organic solvents; , 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n- Octanol, 2-ethylhexanol, sec-octyl alcohol, n-nonanol, n-decyl alcohol, sec-undecanol, trimethylnonanol, sec-tetradecanol, sec-heptadecanol, cyclohexanol, Alcohol solvents such as methylcyclohexanol, benzyl alcohol, ethylene glycol, 1,2-propylene glycol, 1,3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; ethylene glycol Monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, Ethylene glycol mono-n-hexyl ether, ethoxytriethylene glycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether Glycol monoether solvents such as base ethers _; ), carvone, ocimene, phellandrene and other terpene solvents; water, etc. These solvents may be used alone or in combination of two or more.

Among them, from the viewpoint of imparting properties to the semiconductor substrate and pattern forming properties, the above-mentioned solvent preferably contains at least one selected from terpene-based solvents, ester-based solvents, and alcohol-based solvents, and more preferably includes at least one selected from terpene-based solvents. at least one.

When the composition for passivation layer formation contains a solvent, the content rate of a solvent considers provision property, pattern formation property, and storage stability, and is determined. For example, it is preferable that the content rate of a solvent is 5 mass % - 98 mass % in the composition for passivation layer formation from the viewpoint of the imparting property of a composition, and a pattern formability, More preferably, it is 10 mass % - 95 mass %.

(other additives)

The said composition for passivation layer formation may contain an acidic compound or a basic compound. When the composition for passivation layer formation contains an acidic compound or a basic compound, it is preferable to make the content rate of an acidic compound or a basic compound into the composition for passivation layer formation each 1 from a viewpoint of storage stability. mass % or less, more preferably 0.1 mass % or less.

Examples of the acidic compound include Bronsted acid and Lewis acid. Specifically, inorganic acids such as hydrochloric acid and nitric acid; organic acids such as acetic acid; and the like. In addition, examples of basic compounds include Bronsted bases and Lewis bases. Specifically, inorganic bases such as alkali metal hydroxides and alkaline earth metal hydroxides; organic bases such as trialkylamines and pyridine; and the like.

(physical value)

The viscosity of the said composition for passivation layer formation is not specifically limited, According to the provision method etc. to a semiconductor substrate, it can select suitably. For example, the viscosity of the composition for passivation layer forming can be 0.01 Pa·s - 10000 Pa·s. Especially, it is preferable that the viscosity of the composition for passivation layer formation is 0.1 Pa*s - 1000 Pa*s from a viewpoint of pattern formation property. In addition, the above-mentioned viscosity was measured at 25° C. at a shear rate of 1.0 s ⁻¹ using a rotational shear viscometer.

Moreover, although the shear viscosity of the composition for passivation layer formation is not specifically limited, It is preferable to make the composition for passivation layer formation have thixotropy. In particular, when the composition for forming a passivation layer contains a resin, from the viewpoint of pattern formation, the shear viscosity η at a shear rate of 1.0 ^s _is divided by the shear viscosity at a shear rate of 10 ^s The thixotropic ratio (η ₁ /η ₂ ) calculated from η ₂ is preferably 1.05-100, more preferably 1.1-50. In addition, the shear viscosity was measured at a temperature of 25° C. using a rotational shear viscometer equipped with a cone and plate (diameter: 50 mm, cone angle: 1°).

On the other hand, when _the composition for forming a passivation layer contains a high-boiling point material instead of a resin, from the viewpoint of pattern formation, the shear viscosity η at a shear rate of 1.0 s ^-1 is divided by the shear rate The thixotropic ratio (η ₁ /η ₃ ) calculated from the shear viscosity η ₃ at 1000 s ^-1 is preferably 1.05-100, more preferably 1.1-50.

(Manufacturing method of the composition for passivation layer formation)

The manufacturing method of the said composition for passivation layer formation is not specifically limited. For example, the composition for forming a passivation layer can be produced by mixing an organoaluminum compound represented by the general formula (I), a specific alkoxide compound, and optionally a resin, a solvent, and the like by a commonly used mixing method. Moreover, the said composition for passivation layer formation can also be manufactured by mixing the organoaluminum compound represented by General formula (I) and a specific alkoxide compound, after dissolving resin in a solvent.

Furthermore, the organoaluminum compound represented by the general formula (I) can also be prepared by mixing an aluminum alkoxide and a compound capable of forming a chelate with aluminum. At this time, a solvent may be used as needed, or heat treatment may be performed. The composition for passivation layer formation can also be manufactured by mixing the organoaluminum compound represented by general formula (I) prepared in this way, and a specific alkoxide compound, and resin or the solution containing resin.

In addition, the components contained in the composition for forming a passivation layer and the content of each component can be determined using thermal analysis such as differential thermogravimetry (TG/DTA), nuclear magnetic resonance (NMR), infrared spectroscopy (IR ) and other spectroscopic analysis, high performance liquid chromatography (HPLC), gel permeation chromatography (GPC) and other chromatographic analysis for confirmation.

<Semiconductor substrate with passivation layer>

The semiconductor substrate with a passivation layer of the present invention has a semiconductor substrate and a passivation layer provided on the entire surface or a part of the semiconductor substrate, and the passivation layer is heat-treated with the composition for forming a passivation layer of the present invention. Things (fired things). The said semiconductor substrate with a passivation layer shows the passivation effect outstanding by having the passivation layer which is the heat-processed material layer (baked material layer) of the said composition for passivation layer formation.

The semiconductor substrate is not particularly limited, and may be appropriately selected from commonly used semiconductor substrates according to the purpose. Examples of the semiconductor substrate include semiconductor substrates in which silicon, germanium, or the like is doped (diffused) with p-type impurities or n-type impurities. Among them, a silicon substrate is preferable. In addition, the semiconductor substrate may be either a p-type semiconductor substrate or an n-type semiconductor substrate. Among these, a semiconductor substrate in which the surface on which the passivation layer is formed is a p-type layer is preferable from the viewpoint of the passivation effect. The p-type layer on the above-mentioned semiconductor substrate can be a p-type layer derived from a p-type semiconductor substrate, or can be formed on an n-type semiconductor substrate or a p-type semiconductor substrate in the form of a p-type diffusion layer or a p ⁺ type diffusion layer. the p-type layer.

In addition, the thickness of the above-mentioned semiconductor substrate is not particularly limited, and can be appropriately selected according to the purpose. For example, the thickness of the semiconductor substrate can be set to 50 μm to 1000 μm, preferably 75 μm to 750 μm.

The average thickness of the passivation layer formed on the said semiconductor substrate is not specifically limited, It can select suitably according to the objective. For example, the average thickness of the passivation layer is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, and even more preferably 15 nm to 20 μm. The average thickness of the passivation layer can be measured with an interferometric film thickness meter etc.

The above-mentioned semiconductor substrate with a passivation layer can be applied to solar cell elements, light emitting diode elements, and the like. For example, by applying it to a solar cell element, a solar cell element excellent in conversion efficiency can be obtained. When applying the above-mentioned semiconductor substrate with a passivation layer to a solar cell element, the passivation layer is preferably provided on the light-receiving surface side of the solar cell element.

<Manufacturing method of semiconductor substrate with passivation layer>

The manufacturing method of the semiconductor substrate with a passivation layer of this invention, it comprises: the process of forming a composition layer by applying the composition for passivation layer formation of this invention to the whole surface or a part of a semiconductor substrate; Layer heat treatment (firing) to form a passivation layer process. The above-mentioned production method may further include other steps as necessary.

By using the said composition for passivation layer formation, the passivation layer which has a desired shape and has an excellent passivation effect and a large refractive index can be formed with a simple method.

It is preferable that the manufacturing method of the said semiconductor substrate with a passivation layer further has the process of providing alkaline aqueous solution on a semiconductor substrate before the process of forming the said composition layer. That is, it is preferable to wash|clean the surface of a semiconductor substrate with alkaline aqueous solution before providing the said composition for passivation layer forming on a semiconductor substrate. By washing with an aqueous alkali solution, organic substances, fine particles, etc. present on the surface of the semiconductor substrate can be removed, and the passivation effect can be further improved. Generally known RCA washing etc. can be illustrated as a washing|cleaning method by aqueous alkali solution. For example, the semiconductor substrate is immersed in a mixed solution of ammonia water and hydrogen peroxide water and treated at 60° C. to 80° C., whereby organic matter and fine particles can be removed and cleaned. The washing time is preferably 10 seconds to 10 minutes, more preferably 30 seconds to 5 minutes.

In RCA cleaning, first, the wafer is placed in a dilute hydrofluoric acid aqueous solution (HF) to dissolve the thin Si oxide film on the surface and simultaneously remove many foreign substances adhering thereto. Furthermore, organic matter and fine particles are removed with a mixed solution of ammonia water (NH ₄ OH)-hydrogen peroxide (H ₂ O ₂ ) as described above, and then metals are removed with hydrochloric acid (HC1) and hydrogen peroxide (H ₂ O ₂ ). . Then, a final wash is done with ultrapure water.

The method of providing the said composition for passivation layer forming on a semiconductor substrate, and forming a composition layer is not specifically limited. For example, the method of providing the said composition for passivation layer forming on a semiconductor substrate using a well-known coating method etc. is mentioned. Specifically, a dipping method, a printing method, a spin coating method, a brush coating method, a spray method, a doctor blade method, a roll coating method, an inkjet method, etc. are mentioned. Among these, various printing methods, inkjet methods, and the like are preferable from the viewpoint of pattern formation properties.

The provision amount of the said composition for passivation layer formation can be selected suitably according to the objective. For example, the thickness of the passivation layer formed can be adjusted suitably so that it may become desired thickness mentioned later.

A passivation layer can be formed on a semiconductor substrate by heat-processing (baking) the composition layer formed from the composition for passivation layer formation, and forming the heat-processed material layer (baked material layer) derived from the said composition layer.

Regarding the heat treatment (firing) conditions of the composition layer, as long as the organoaluminum compound represented by the general formula (I) and the specific alkoxide compound contained in the composition layer can be converted into Aluminum oxide (Al ₂ O ₃ ) and composite oxides are not particularly limited. Among them, heat treatment (firing) conditions are preferable to form a layer containing Al ₂ O ₃ having no specific crystal structure and an amorphous shape. By making the passivation layer consist of a layer containing amorphous Al ₂ O ₃ , the passivation layer can be negatively charged more effectively, and a more excellent passivation effect can be obtained. Specifically, the heat treatment (calcination) temperature is preferably 400°C to 900°C, more preferably 450°C to 800°C. In addition, the heat treatment (firing) time can be appropriately selected according to the heat treatment (firing) temperature and the like. For example, it can be 0.1 hour - 10 hours, Preferably it is 0.2 hour - 5 hours.

The thickness of the passivation layer manufactured by the manufacturing method of the said semiconductor substrate with a passivation layer is not specifically limited, It can select suitably according to the objective. For example, the average thickness of the passivation layer is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, and even more preferably 15 nm to 20 μm.

In addition, the average thickness of the passivation layer formed is by using a stylus type height difference-surface shape measuring device (such as Ambios company), an interferometric film thickness meter (such as FILMETRICS company) etc. and measuring the thickness of 3 points according to a conventional method, Then calculate its arithmetic mean.

The above-mentioned method for producing a semiconductor substrate with a passivation layer may further include a combination of forming the passivation layer-forming composition after applying the passivation layer-forming composition and before the step of forming the passivation layer by heat treatment (firing). The process of drying the material layer. By having the process of drying a composition layer, the passivation layer which has a more uniform passivation effect can be formed.

The process of drying a composition layer will not be specifically limited if at least a part of the solvent which may be contained in the composition for passivation layer formation can be removed. The drying treatment may be, for example, heat treatment at 30°C to 250°C for 1 minute to 60 minutes, preferably heat treatment at 40°C to 220°C for 3 minutes to 40 minutes. In addition, the drying treatment may be performed under normal pressure or under reduced pressure.

In the case where the composition for passivation layer formation contains resin, the manufacturing method of the said semiconductor substrate with a passivation layer may be performed before the process of forming a passivation layer by heat treatment (firing) after imparting the composition for passivation layer formation. It also has the process of degreasing the composition layer formed from the composition for passivation layer forming. Since there is a step of degreasing the composition layer, it is possible to form a passivation layer having a more uniform semiconductor substrate passivation effect.

The step of degreasing the composition layer will not be particularly limited as long as at least a part of the resin that may be contained in the composition for passivation layer formation can be removed. The degreasing treatment can be performed, for example, at 250° C. to 400° C. for 3 minutes to 120 minutes, preferably at 300° C. to 450° C. for 10 minutes to 60 minutes. In addition, the degreasing treatment is preferably performed in the presence of oxygen, more preferably in the air.

<Solar cell element>

The solar cell element of the present invention has: a semiconductor substrate formed by pn-joining a p-type layer and an n-type layer; A heat-treated product (fired product) of the composition for forming a passivation layer of the present invention; and an electrode disposed on one or more layers selected from the p-type layer and the n-type layer of the semiconductor substrate. The above-mentioned solar cell element may further have other constituent elements as needed.

The said solar cell element becomes excellent in conversion efficiency by having the passivation layer formed from the composition for passivation layer forming of this invention.

It does not specifically limit as a semiconductor substrate which provides the composition for passivation layer formation, It can select suitably from the semiconductor substrate normally used according to the objective. As the semiconductor substrate, the semiconductor substrate described in the semiconductor substrate with a passivation layer can be used, and the semiconductor substrate that can be preferably used is also the same. The surface of the semiconductor substrate on which the passivation layer is provided may be a p-type layer or an n-type layer. Among them, a p-type layer is preferable from the viewpoint of conversion efficiency. The p-type layer on the above-mentioned semiconductor substrate can be a p-type layer derived from a p-type semiconductor substrate, or can be formed on an n-type semiconductor substrate or a p-type semiconductor substrate in the form of a p-type diffusion layer or a p ⁺ type diffusion layer. the p-type layer. Moreover, it is preferable that the surface of the semiconductor substrate provided with the said passivation layer is a light-receiving surface in a solar cell element.

The thickness of the above-mentioned semiconductor substrate is not particularly limited, and can be appropriately selected according to the purpose. For example, it can be set to 50 μm to 1000 μm, preferably 75 μm to 750 μm.

In addition, the thickness of the passivation layer formed on the said semiconductor substrate is not specifically limited, It can select suitably according to the objective. For example, the average thickness of the passivation layer is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, and even more preferably 15 nm to 20 μm.

There are no limitations on the shape, size, etc. of the above-mentioned solar cell element. For example, it is preferably a square whose side length is 125 mm to 156 mm.

<Manufacturing method of solar cell element>

The method for manufacturing a solar cell element according to the present invention includes: having a pn junction formed by joining a p-type layer and an n-type layer and having an electrode on one or more layers selected from the p-type layer and n-type layer A step of applying the composition for forming a passivation layer of the present invention to at least a part of the surface having the electrode of the semiconductor substrate to form a composition layer; and forming a passivation layer by heat-treating (firing) the composition layer process. The manufacturing method of the said solar cell element may further have another process as needed.

By using the said composition for passivation layer forming, the solar cell element which has the passivation layer which has an excellent passivation effect and has a large refractive index, and is excellent in conversion efficiency can be manufactured by a simple method. Furthermore, the passivation layer can be formed in a desired shape on the semiconductor substrate on which the electrode was formed, and the productivity of a solar cell element can be made excellent.

A semiconductor substrate having a pn junction in which an electrode is arranged on at least one of the p-type layer and the n-type layer can be produced by a generally used method. For example, the semiconductor substrate can be produced by applying an electrode-forming paste such as silver paste or aluminum paste to a desired region of the semiconductor substrate, and performing heat treatment (firing) as necessary.

The surface of the semiconductor substrate on which the passivation layer is provided may be a p-type layer or an n-type layer. Among them, a p-type layer is preferable from the viewpoint of conversion efficiency.

The detail of the method of forming a passivation layer using the said composition for passivation layer formation is the same as the manufacturing method of the semiconductor substrate with a passivation layer already mentioned, and a preferable aspect is also the same.

The thickness of the passivation layer formed on the said semiconductor substrate is not specifically limited, It can select suitably according to the objective. For example, the average thickness of the passivation layer is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, and even more preferably 15 nm to 20 μm.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1( a ) to FIG. 1( d ) are process diagrams schematically showing an example of the method for manufacturing a solar cell element having a passivation layer according to the present embodiment as a cross-sectional view. However, this process diagram does not limit the present invention in any way.

As shown in (a) of FIG. 1 , an n ⁺ -type diffusion layer 2 is formed near the surface of a p-type semiconductor substrate 1 , and an antireflection film 3 is formed on the outermost surface. As the antireflection film 3, a silicon nitride film, a titanium oxide film, etc. are mentioned. A surface protection film (not shown) such as silicon oxide may further exist between the antireflection film 3 and the p-type semiconductor substrate 1 . In addition, since the passivation layer of the present invention has a large refractive index, it is preferable to form the passivation layer (not shown) between the antireflection film 3 and the p-type semiconductor substrate 1 . Although not shown in FIG. 1( a ) to FIG. 1( d ), a method for manufacturing a solar cell element having a passivation layer on the light-receiving surface side will be described later using FIG. 3 .

Next, as shown in FIG. 1( b ), after applying a material for forming the back electrode 5 such as an aluminum electrode paste on a part of the back surface of the p-type semiconductor substrate 1, heat treatment (firing) is performed to form the back electrode 5, Then, aluminum atoms are diffused into p-type semiconductor substrate 1 to form p ⁺ -type diffusion layer 4 .

Next, as shown in FIG. 1( c ), after coating the electrode-forming paste on the light-receiving surface side of the p-type semiconductor substrate 1 , heat treatment (firing) is performed to form the light-receiving surface electrode 7 . By using a material containing glass powder having fire through properties as the paste for electrode formation, the antireflection film 3 can be formed on the n ⁺ -type diffusion layer 2 as shown in (c) of FIG. 1 . The light-receiving surface electrode 7 is in ohmic contact.

In addition, in Fig. 1(a) to Fig. 1(d), Fig. 1(b) and Fig. 1(c) are shown as separate steps, but Fig. 1( The steps of b) and (c) of FIG. 1 are combined into one step. Specifically, after applying a material for forming the rear electrode 5 such as an aluminum electrode paste on a part of the rear surface in (b) of FIG. 1 above and before performing heat treatment (firing) for forming the rear electrode 5, the The electrode-forming paste is applied on the light-receiving surface side, and heat treatment (firing) is performed at this stage. In the case of this method, the electrodes on the back surface and the light-receiving surface are formed by one heat treatment, thereby simplifying the process.

Then, as shown in FIG. 1( d ), the composition for passivation layer formation is provided on the back p-type layer except the area|region in which the back electrode 5 was formed, and the composition layer is formed. The application can be performed by methods such as screen printing, for example. The passivation layer 6 is formed by heat-treating (firing) the composition layer formed on the p-type layer. A solar cell element excellent in power generation efficiency can be manufactured by forming the passivation layer 6 formed from the said composition for passivation layer forming on the back p-type layer.

In the solar cell element manufactured by the manufacturing method including the manufacturing steps shown in (a) to (d) of FIG. Qu and so on. Furthermore, by using the said composition for passivation layer forming, a passivation layer can be formed with excellent productivity only in a specific position (specifically, on the p-type layer except the region in which an electrode was formed).

In addition, the method of forming a passivation layer only in the back part of the semiconductor substrate 1 was shown in (d) of FIG. This is then heat-treated (fired) to form passivation layer 6 (not shown) also on the side surface (edge) of semiconductor substrate 1 . Thereby, a solar cell element with better power generation efficiency can be manufactured.

Moreover, you may form a passivation layer by applying the composition for passivation layer formation of this invention only to a side surface, and heat-processing (baking) it, without forming a passivation layer in a back surface part. When the composition for passivation layer formation of this invention is used for the position with many crystal defects like a side surface, the effect is large especially.

In Fig. 1(a) to Fig. 1(d), the method of forming the passivation layer after the formation of the electrodes has been described, but it is also possible to form aluminum in the desired area by vapor deposition or the like after the formation of the passivation layer. etc. electrodes.

2( a ) to 2( e ) are process diagrams schematically showing another example of the method for manufacturing a solar cell element having a passivation layer according to one embodiment of the present invention in cross-sectional view. Specifically, Fig. 2(a) to Fig. 2(e) are sectional views illustrating process diagrams including the following steps: p-type diffusion that can form a p ⁺ -type diffusion layer using aluminum electrode paste or thermal diffusion treatment. After forming the p ⁺ -type diffusion layer with the layer-forming composition, the heat-treated product of the aluminum electrode paste or the heat-treated product of the p ⁺ -type diffusion layer-forming composition is removed. Here, examples of the composition for forming a p-type diffusion layer include compositions containing an acceptor element-containing substance and a glass component.

As shown in FIG. 2( a ), n ⁺ -type diffusion layer 2 is formed near the surface of p-type semiconductor substrate 1 , and antireflection film 3 is formed on the surface. As the antireflection film 3, a silicon nitride film, a titanium oxide film, etc. are mentioned.

Next, as shown in FIG. 2( b ), the p ⁺ -type diffusion layer-forming composition is applied to a part of the back surface, and then heat-treated to form the p ⁺ -type diffusion layer 4 . Heat-treated product 8 of the p ⁺ -type diffusion layer-forming composition is formed on p ⁺ -type diffusion layer 4 .

Here, an aluminum electrode paste may be used instead of the composition for forming a p-type diffusion layer. In the case of using an aluminum electrode paste, aluminum electrode 8 is formed on p ⁺ -type diffusion layer 4 .

Next, as shown in (c) of FIG. 2 , the heat-treated product 8 of the composition for forming a p ^- type diffusion layer formed on the p + -type diffusion layer 4 or the aluminum electrode 8 is removed by etching or the like.

Next, as shown in FIG. 2( d ), after selectively coating the electrode-forming paste on the light-receiving surface (surface) and a part of the back surface of the semiconductor substrate 1, heat treatment is performed to form a light-receiving surface (surface) on the light-receiving surface (surface). The surface electrode 7 is formed, and the back electrode 5 is formed on the back surface. By using a substance containing glass powder having fire-through properties as the paste for electrode formation coated on the light-receiving surface side, it is possible to penetrate the anti-reflection film 3 as shown in ^FIG . 2 to form a light-receiving surface electrode 7 to obtain an ohmic contact.

In addition, since the p ⁺ -type diffusion layer 4 has already been formed in the region where the back electrode is formed, the electrode-forming paste used to form the back electrode 5 is not limited to aluminum electrode paste, and silver electrode paste can also be used to form Electrode paste for electrodes with lower resistance. Accordingly, it is also possible to further improve the power generation efficiency.

Then, as shown in FIG.2(e), the composition for passivation layer formation is provided on the back p-type layer except the area|region where the back electrode 5 was formed, and the composition layer is formed. The application can be performed by methods such as screen printing, for example. The passivation layer 6 is formed by heat-treating (firing) the composition layer formed on the p-type layer. By forming the passivation layer 6 formed from the composition for passivation layer formation of this invention on the p-type layer of the back surface, the solar cell element excellent in power generation efficiency can be manufactured.

2(e) shows a method of forming a passivation layer only on the back side of the semiconductor substrate 1, but it is also possible to provide a passivation layer forming material on the side of the p-type semiconductor substrate 1 other than the back side. This is then heat-treated (fired) to form a passivation layer (not shown) also on the side (edge) of the p-type semiconductor substrate 1 . Thereby, a solar cell element with better power generation efficiency can be manufactured.

Moreover, you may form a passivation layer by providing the composition for passivation layer formation of this invention only in the side surface of a semiconductor substrate, and heat-processing (baking) it, without forming a passivation layer in a back surface part. When the composition for passivation layer formation of this invention is used for the position with many crystal defects like a side surface, the effect is large especially.

In Fig. 2(a) to Fig. 2(e), the method of forming the passivation layer after the formation of the electrodes has been described, but it is also possible to form aluminum in the desired area by vapor deposition or the like after the formation of the passivation layer. etc. electrodes.

In the above-mentioned embodiment, the case of using the p-type semiconductor substrate with the n ⁺ type diffusion layer formed on the light receiving surface has been described, but in the case of using the n type semiconductor substrate with the p ⁺ type diffusion layer formed on the light receiving surface, the A solar cell element can be produced similarly. In this case, an n ⁺ -type diffusion layer is formed on the back side.

Furthermore, the composition for passivation layer forming can also be used for forming the passivation layer 6 of the light receiving surface side or the back side of the back electrode type solar cell element which arrange|positioned the electrode only on the back side as shown in FIG.

As shown in the schematic cross-sectional view of FIG. 3 , n ⁺ -type diffusion layer 2 is formed near the light-receiving surface side of p-type semiconductor substrate 1 , and passivation layer 6 and antireflection film 3 are formed on the surface. As the antireflection film 3 , a silicon nitride film, a titanium oxide film, and the like are known. Moreover, the passivation layer 6 is formed by providing the composition for passivation layer formation of this invention, and heat-processing (baking) it. Since the passivation layer of the present invention exhibits a favorable refractive index, it is considered that power generation efficiency can be improved by providing the passivation layer on the light-receiving surface side.

A back electrode 5 is provided on the p ⁺ -type diffusion layer 4 and n ⁺ -type diffusion layer 2 on the back side of the p-type semiconductor substrate 1 , and a passivation layer 6 is provided on a region of the back where no electrodes are formed.

The p ⁺ -type diffusion layer 4 can be formed by applying a p-type diffusion layer-forming composition or an aluminum electrode paste to a desired region as described above, and then heat-treating it. In addition, the n ⁺ -type diffused layer 2 can be formed, for example, by applying a composition for forming an n -type diffused layer capable of forming an n ⁺ -type diffused layer by thermal diffusion treatment on a desired region, and then heat-treating it.

Here, examples of the composition for forming an n-type diffusion layer include compositions containing a donor element-containing substance and a glass component.

Rear electrode 5 respectively provided on p ⁺ -type diffusion layer 4 and n + -type diffusion layer 2 can be formed by using a generally used electrode-forming paste such as silver electrode paste.

In addition, the back electrode 5 provided on the p ⁺ -type diffusion layer 4 may be an aluminum electrode formed together with the p ⁺ -type diffusion layer 4 using an aluminum electrode paste.

The passivation layer 6 provided in the back surface can be formed by providing the composition for passivation layer forming in the area|region where the back surface electrode 5 is not provided, and heat-processing (baking) it.

In addition, the passivation layer 6 may be formed not only on the back surface of the semiconductor substrate 1 but also on the side surface (not shown).

In the back electrode type solar cell element shown in FIG. 3 , since no electrode is provided on the light-receiving surface side, the power generation efficiency is excellent. Furthermore, since the passivation layer is formed in the region where no electrode is formed on the back surface, the conversion efficiency is further improved.

The above shows an example of using a p-type semiconductor substrate as the semiconductor substrate, but a solar cell element excellent in conversion efficiency can also be manufactured as described above when an n-type semiconductor substrate is used. The shape and size of the solar cell element are not limited, but a square with a side length of usually 125 mm to 156 mm is preferable.

<solar battery>

A solar cell includes the solar cell element of the present invention and a wiring material disposed on electrodes of the solar cell element. The solar cell can also be connected to a plurality of solar cell elements by wiring materials such as tab wires as required, and sealed by a sealing material.

The above-mentioned wiring material and sealing material are not particularly limited, and can be appropriately selected from materials generally used in this technical field.

There is no limitation on the size of the above-mentioned solar cells. The size of the solar cell is preferably 0.5 m ² to 3 m ² .

Example

Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these Examples. In addition, unless otherwise stated, "%" is a mass standard.

<Example 1>

(Preparation of composition 1 for passivation layer formation)

Mix 5.00 g of ethyl cellulose (Nissei Co., Ltd., trade name: ETHOCEL 200cps) and 95.02 g of terpineol (NIPPON TERPENE CHEMICALS, INC.), and stir at 150°C for 1 hour to prepare an ethyl cellulose solution .

Next, 15.1 g of aluminum diisopropoxide ethylacetoacetate (Kawaken Fine Chemicals Co., Ltd., trade name: ALCH), 5.1 g of niobium ethoxide (Wako Pure Chemical Industries, Ltd.), titanium tetraisopropoxide (Wako Junyaku Kogyo Co., Ltd.) 5.0 g, 35.2 g of the above-mentioned ethyl cellulose solution, and 30.2 g of terpineol (NIPPON TERPENE CHEMICALS, INC.) were mixed to prepare composition 1 for passivation layer formation.

(formation of passivation layer)

A single-crystal p-type silicon substrate (manufactured by Sumco Corporation, 50 mm square, thickness: 625 μm) with a mirror surface shape was used as a semiconductor substrate. The silicon substrate was pretreated by immersion washing at 70° C. for 5 minutes using an RCA cleaning solution (Kanto Chemical Co., Ltd., trade name: Frontier Cleaner-A01).

Then, the above-obtained passivation layer-forming composition 1 was applied to the entire surface of the pretreated silicon substrate using a screen printing method so that the film thickness after drying became 5 μm, and the process was performed at 150° C. for 5 minutes. Dry processing. Next, after heat-processing (firing) at 700 degreeC for 10 minutes, it left to cool at room temperature, and produced the board|substrate for evaluation.

<Evaluation>

The composition for passivation layer formation obtained above and the board|substrate for evaluation produced using this composition were evaluated as follows, and the evaluation result is shown in Table 1.

(evaluation of thixotropic ratio)

Cone plate (diameter 50mm, cone angle 1°) is installed on the rotational shear viscometer (AntonPaar company, trade name: MCR301), and under the condition of temperature 25 ℃, shear rate 1.0s ^-1 and 10s ^-1 The shear viscosity of the composition 1 for passivation layer formation produced above was measured immediately after preparation (within 12 hours), respectively.

The shear viscosity (η ₁ ) at a shear rate of 1.0s ^-1 is 44.0Pa·s, and the shear viscosity (η ₂ ) at a shear rate of 10s ^-1 is 35.0Pa·s . The thixotropic ratio (η ₁ /η ₂ ) at the shear viscosities of 1.0s ^-1 and 10s ^-1 was 1.3.

(evaluation of storage stability)

The shear viscosity of the composition 1 for passivation layer formation prepared above was measured, respectively, immediately after preparation (within 12 hours) and after storing at 25 degreeC for 30 days. Cone and plate (diameter 50 mm, cone angle 1°) were mounted on MCR301 (trade name, Anton Paar Co.), and the shear viscosity was measured at a temperature of 25° C. and a shear rate of 1.0 s ⁻¹ .

The shear viscosity (η ₀ ) at 25°C immediately after preparation was 44.0 Pa·s, and the shear viscosity (η ₃₀ ) at 25°C after storage at 25°C for 30 days was 44.6 Pa·s.

The rate of change in shear viscosity after storage at 25° C. for 30 days was calculated from the following formula (B), and the storage stability was evaluated according to the following evaluation criteria.

Change rate of shear viscosity (%)=(η ₃₀ -η ₀ )/(η ₀ )×100 (B)

[evaluation criteria]

A: The rate of change in shear viscosity is less than 10%.

B: The change rate of the shear viscosity is 10% or more and less than 30%.

C: The change rate of the shear viscosity is 30% or more.

If evaluation is A or B, it is favorable as a composition for passivation layer forming.

(measurement of effective life)

The useful life (μs) of the evaluation substrate obtained above was measured at room temperature (25°C) by using a service life measuring device (Smirebo Corporation, trade name: WT-2000PVN). Determination. The effective lifetime of the region provided with the composition for semiconductor substrate passivation layer forming of the obtained board|substrate for evaluation was 300 microseconds.

(Determination of thickness and refractive index of passivation layer)

The average thickness and refractive index of the passivation layer on the board|substrate for evaluation obtained above were measured using the interferometric film thickness meter (FILMETRICS Corporation, F20 film thickness measuring system). The passivation layer has a thickness of 220 nm and a refractive index of 1.71.

<Example 2>

(Preparation of Passivation Layer Forming Composition 2)

14.9 g of aluminum ethylacetoacetate diisopropoxide, 9.8 g of titanium tetraisopropoxide, 35.1 g of the said ethyl cellulose solution, and 29.7 g of terpineol were mixed, and the composition 2 for passivation layer formation was prepared.

Except having used the composition 2 for passivation layer formation, it evaluated similarly to Example 1, and the result is shown in Table 1.

<Example 3>

(Preparation of Passivation Layer Forming Composition 3)

Mix 15.0 g of aluminum diisopropoxide ethylacetoacetate, 10.2 g of zirconium ethoxide (Wako Pure Chemical Industries, Ltd.), 35.1 g of the above-mentioned ethyl cellulose solution, and 30.4 g of terpineol to prepare a passivation layer forming combination Object 3.

Except having used the composition 3 for passivation layer formation, it evaluated similarly to Example 1, and the result is shown in Table 1.

<Example 4>

(Preparation of Passivation Layer Forming Composition 4)

15.2 g of aluminum diisopropoxide ethylacetoacetate, 10.0 g of niobium ethoxide, 5.1 g of titanium ethoxide, 4.8 g of tetraethyl orthosilicate (Wako Pure Chemical Industries, Ltd.), 34.7 g of the above-mentioned ethyl cellulose solution and terpene Pinitol 30.3g was mixed, and the composition 4 for passivation layer formation was prepared.

Except having used the composition 4 for passivation layer formation, it evaluated similarly to Example 1, and Table 1 shows the result.

<Example 5>

(Preparation of Passivation Layer Forming Composition 5)

Mix 14.9 g of aluminum diisopropoxide ethylacetoacetate, 15.2 g of titanium ethoxide, 5.2 g of tetraethyl orthosilicate, 34.8 g of the above-mentioned ethyl cellulose solution and 30.6 g of terpineol to prepare a passivation layer forming Composition 5.

Except having used the composition 5 for passivation layer formation, it evaluated similarly to Example 1, and the result is shown in Table 1.

<Example 6>

(Preparation of Passivation Layer Forming Composition 6)

Mix 15.0 g of aluminum diisopropoxide ethyl acetoacetate, 15.1 g of zirconium ethoxide, 5.1 g of tetraethyl orthosilicate, 35.3 g of the above-mentioned ethyl cellulose solution and 29.6 g of terpineol to prepare a passivation layer forming Composition 6.

Except having used the composition 6 for passivation layer forming, it evaluated similarly to Example 1, and Table 1 shows the result.

<Example 7>

(Preparation of Passivation Layer Forming Composition 7)

15.1 g of aluminum diisopropoxide ethylacetoacetate, 5.0 g of niobium ethoxide, 5.0 g of titanium isopropoxide, 35.2 g of isobornyl cyclohexanol (NIPPON TERPENE CHEMICALS, INC., trade name: Terusolve MTPH) and terpine Alcohol 14.9g was mixed, and the composition 7 for passivation layer formation was prepared.

Except having used the composition 7 for passivation layer formation, it evaluated similarly to Example 1, and the result is shown in Table 1. In addition, the thixotropic ratio is defined as the ratio (η 1 /η 3 ) of the shear viscosity (η ₁ ) at a shear rate _of 1.0 s ^-1 to the shear viscosity ( _{η 3} ) at a shear rate of 1000 s ^-1 form to calculate.

<Embodiment 8>

(Preparation of composition 8 for passivation layer formation)

15.2 g of aluminum ethylacetoacetate diisopropoxide, 10.2 g of titanium isopropoxide, 34.8 g of isobornylcyclohexanol, and 15.2 g of terpineol were mixed to prepare composition 8 for passivation layer formation.

Except having used the composition 8 for passivation layer formation, it evaluated similarly to Example 1, and Table 1 shows the result. In addition, the thixotropic ratio is defined as the ratio (η 1 /η 3 ) of the shear viscosity (η ₁ ) at a shear rate _of 1.0 s ^-1 to the shear viscosity ( _{η 3} ) at a shear rate of 1000 s ^-1 form to calculate.

<Example 9>

(Preparation of Passivation Layer Forming Composition 9)

14.8 g of aluminum ethylacetoacetate diisopropoxide, 9.8 g of zirconium ethoxide, 35.5 g of isobornylcyclohexanol, and 15.2 g of terpineol were mixed to prepare composition 9 for passivation layer formation.

Except having used the composition 9 for passivation layer formation, it evaluated similarly to Example 1, and the result is shown in Table 1. In addition, the thixotropic ratio is defined as the ratio (η 1 /η 3 ) of the shear viscosity (η ₁ ) at a shear rate _of 1.0 s ^-1 to the shear viscosity ( _{η 3} ) at a shear rate of 1000 s ^-1 form to calculate.

<Comparative example 1>

(Preparation of Passivation Layer Forming Composition 10)

15.0 g of aluminum ethylacetoacetate diisopropoxide, 35.0 g of the said ethyl cellulose solution, and 30.2 g of terpineol were mixed, and the composition 10 for passivation layer formation was prepared.

Except having used the composition 10 for passivation layer formation, it evaluated similarly to Example 1, and the result is shown in Table 1.

<Comparative example 2>

(Preparation of Passivation Layer Forming Composition 11)

15.1 g of aluminum ethylacetoacetate diisopropoxide, 34.9 g of isobornylcyclohexanol, and 15.2 g of terpineol were mixed, and the composition 11 for passivation layer formation was prepared.

Except having used the composition 11 for passivation layer formation, it evaluated similarly to Example 1, and Table 1 shows the result. In addition, the thixotropic ratio is defined as the ratio (η 1 /η 3 ) of the shear viscosity (η ₁ ) at a shear rate _of 1.0 s ^-1 to the shear viscosity ( _{η 3} ) at a shear rate of 1000 s ^-1 form to calculate.

【Table 1】

From the above, it turns out that the passivation layer which has an excellent passivation effect and has a large refractive index can be formed by using the composition for passivation layer formation of this invention. Moreover, it turned out that the composition for passivation layer formation of this invention is excellent in storage stability. Furthermore, it turned out that the passivation layer of a desired shape can be formed in a simple process by using the composition for passivation layer formation of this invention.

In addition, the disclosure of Japanese Patent Application No. 2012-156472 and Japanese Patent Application No. 2012-218389 is incorporated in this specification as a reference in its entirety.

All documents, patent applications, and technical standards described in this specification are incorporated by reference in this specification to the same extent as if each document, patent application, and technical standard were specifically and individually described.

Claims (13)

1. a passivation layer formation composition, it comprises the organo-aluminum compound shown in following general formula (I) and is selected from least one alkoxide compound in titanium alkoxide, zirconium alkoxides and silicon alkoxide,

In general formula (I), R ¹separately represent the alkyl of carbon number 1 ~ 8, n represents the integer of 0 ~ 3, X ²and X ³separately represent oxygen atom or methylene, R ², R ³and R ⁴separately represent the alkyl of hydrogen atom or carbon number 1 ~ 8.

2. passivation layer formation composition according to claim 1, it also comprises alkanol niobium.

3. passivation layer formation composition according to claim 2, wherein, described alkanol niobium is be selected from least one in ethanol niobium, isopropyl alcohol niobium, normal propyl alcohol niobium, n-butanol niobium and phenol niobium.

4. the passivation layer formation composition according to any one of claims 1 to 3, wherein, described alkoxide compound at least comprises described titanium alkoxide, and described titanium alkoxide is for being selected from least one in methyl alcohol titanium, titanium ethanolate, isopropyl titanate, normal propyl alcohol titanium, n-butyl titanium, tert-butyl alcohol titanium, titanium isobutoxide, diisopropoxy bis-acetylacetonate titanium and four (2-ethyl-1-hexanol) titanium.

5. the passivation layer formation composition according to any one of Claims 1 to 4, wherein, described alkoxide compound at least comprises described zirconium alkoxides, and described zirconium alkoxides is be selected from least one in ethanol zirconium, zirconium iso-propoxide, zirconium-n-propylate, zirconium-n-butylate, zirconium tert-butoxide, acetylacetone,2,4-pentanedione zirconium, trifluoroacetylacetone (TFA) zirconium and hexafluoroacetylacetone zirconium.

6. the passivation layer formation composition according to any one of Claims 1 to 5, wherein, described alkoxide compound at least comprises described silicon alkoxide, and described silicon alkoxide is the silicon alkoxide shown in following general formula (II),

(R ⁵O) _(4-m)SiR ⁶ _m(II)

In general formula (II), R ⁵and R ⁶separately represent the alkyl of carbon number 1 ~ 8, m represents the integer of 0 ~ 3.

7. the passivation layer formation composition according to any one of claim 1 ~ 6, it also comprises resin.

8. the passivation layer formation composition according to any one of claim 1 ~ 7, it also comprises the compound shown in following general formula (III)

9. the semiconductor substrate with passivation layer, it has semiconductor substrate and is arranged at the passivation layer of on described semiconductor substrate whole or a part, the heat treatment thing of the passivation layer formation composition of described passivation layer according to any one of claim 1 ~ 8.

10. a manufacture method for the semiconductor substrate with passivation layer, it comprises:

Passivation layer formation composition according to any one of 1 ~ 8 is required to whole on semiconductor substrate or a part of entitle and forms the operation of composition layer; With

Described composition layer is heat-treated and forms the operation of passivation layer.

11. 1 kinds of solar cell devices, it has:

P-type layer and n-layer are carried out the semiconductor substrate that pn engages;

Be arranged at the passivation layer of on described semiconductor substrate whole or a part, the heat treatment thing of the passivation layer formation composition of described passivation layer according to any one of claim 1 ~ 8; With

Be configured at the electrode on the layer of more than 1 being selected from described p-type layer and n-layer of described semiconductor substrate.

The manufacture method of 12. 1 kinds of solar cell devices, it comprises:

To there is the pn knot that p-type layer and n-layer engaged and on the layer being selected from more than 1 in described p-type layer and described n-layer, there is the semiconductor substrate of electrode, the face with described electrode at least partially, the passivation layer formation composition of entitle requirement according to any one of 1 ~ 8 and form the operation of composition layer; With

Described composition layer is heat-treated and forms the operation of passivation layer.

13. 1 kinds of solar cells, it has solar cell device according to claim 11 and is configured at the wiring material on the electrode of described solar cell device.