JP2014072449A - Composition for formation of semiconductor substrate passivation film, semiconductor substrate with passivation film and manufacturing method thereof, and solar battery element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for formation of a semiconductor substrate passivation film which makes possible to form a semiconductor substrate passivation film in a desired shape by a simple and convenient method, and which has good storage stability, suppresses the occurrence of unevenness in printing, and allows a good coating film uniformity to develop.SOLUTION: A composition for formation of a semiconductor substrate passivation film comprises: an organic aluminum compound expressed by the general formula (I) below; and at least one selected from a fluorine-based surfactant and a silicone-based surfactant. In the formula (I), R's represent an alkyl group with 1-8 carbon atoms independently of each other; n represents an integer of 0-3; Xand Xrepresent an oxygen atom or a methylene group independently of each other; and R, Rand Rrepresent a hydrogen atom or an alkyl group with 1-8 carbon atoms independently of each other. [Formula (I)]

Description

  The present invention relates to a composition for forming a semiconductor substrate passivation film, a semiconductor substrate with a passivation film, a method for producing the same, and a solar cell element.

The manufacturing process of the conventional silicon solar cell element is demonstrated.
First, a p-type silicon substrate having a textured structure is prepared so as to promote the light confinement effect and increase the efficiency, and subsequently, 800 ° C. to 900 ° C. in a mixed gas atmosphere of phosphorus oxychloride (POCl ₃ ), nitrogen, and oxygen. An n-type diffusion layer is uniformly formed by performing several tens of minutes at a temperature.
In this conventional method, since phosphorus is diffused using a mixed gas, n-type diffusion layers are formed not only on the surface but also on the side surface and the back surface. Therefore, side etching is performed to remove the n-type diffusion layer on the side surface. In addition, the n-type diffusion layer formed on the back surface needs to be converted into a p ⁺ -type diffusion layer. By applying aluminum powder and a binder aluminum paste to the entire back surface, and baking this to form an aluminum electrode, At the same time that the n-type diffusion layer is changed to the p ⁺ -type diffusion layer, an ohmic contact is obtained.

  Here, the aluminum electrode formed from the aluminum paste has low electrical conductivity, and in order to reduce the sheet resistance, the aluminum electrode generally formed on the entire back surface must have a thickness of about 10 μm to 20 μm after firing. However, since the thermal expansion coefficients of silicon and aluminum, which are substrates, differ greatly, a large internal stress is generated in the silicon substrate during firing and cooling, causing grain boundary damage, crystal defect growth, and warping. It becomes.

In order to solve this problem, there is a method of reducing the coating amount of the aluminum paste and thinning the aluminum electrode layer. However, when the amount of aluminum paste applied is reduced, the amount of aluminum diffusing from the surface of the p-type silicon semiconductor substrate becomes insufficient. As a result, the desired BSF (Back Surface Field) effect (the effect of improving the collection efficiency of the generated carriers due to the presence of the p ⁺ -type diffusion layer) cannot be achieved, resulting in a problem that the characteristics of the solar cell deteriorate. .

In relation to the above, there has been proposed a point-contant method in which an aluminum paste is applied to a part of the silicon substrate surface to partially form a p ⁺ -type diffusion layer and an aluminum electrode (for example, Patent Document 1). reference). In the case of a solar cell having a point contact structure on the side opposite to the light receiving surface (hereinafter also referred to as “back side”), in order to suppress the recombination rate of minority carriers on the surface of the portion other than the aluminum electrode A semiconductor substrate passivation film for the back side (hereinafter also simply referred to as “passivation film”) is used. As such a passivation film, a SiO ₂ film or the like has been proposed (for example, see Patent Document 2). As a passivation effect by forming such an oxide film, there is an effect of terminating the dangling bonds of silicon atoms on the back surface portion of the silicon substrate and reducing the surface state density that causes recombination.

As another method for suppressing recombination of minority carriers, there is a method of reducing the minority carrier density by an electric field that generates fixed charges in the passivation film. Such a passivation effect is generally called a field effect, and an aluminum oxide (Al ₂ O ₃ ) film or the like has been proposed as a material having a negative fixed charge (see, for example, Patent Document 3).
Such a passivation film is generally formed by a method such as an ALD (Atomic Layer Deposition) method or a CVD (Chemical Vapor Depositon) method (see, for example, Non-Patent Document 1). As a simple method for forming an aluminum oxide film on a semiconductor substrate, a sol-gel method has been proposed (see, for example, Non-Patent Documents 2 to 4).

Japanese Patent No. 3107287 Japanese Patent Laid-Open No. 2004-6565 Japanese Patent No. 4767110

Journal of Applied Physics, 104 (2008), 113703-1-113703-7 Thin Solid Films, 517 (2009), 088102-1〜088102-4 Chinese Physics Letters, 26 (2009), 088102 Nippon Seramikkusu Kyokai Gakujitsu Ronbunshi, 97 (1989) 369-399

Since the method described in Non-Patent Document 1 includes a complicated manufacturing process such as vapor deposition, it may be difficult to improve productivity. Moreover, in the composition for forming a passivation film used in the methods described in Non-Patent Documents 2 to 4, problems such as gelation occur with time, and it is difficult to say that the storage stability is sufficient.
Further, the passivation film forming composition used in the methods described in Non-Patent Documents 2 and 3 has poor wettability with a semiconductor substrate, and therefore, in the step of forming an aluminum oxide film by a sol-gel method, printing unevenness or coating film It was difficult to form a coating film with a uniform thickness and a passivation film with a uniform thickness. Printing unevenness is a phenomenon that the composition for forming a semiconductor substrate passivation film becomes extremely thinner than the surroundings because the wetness with the semiconductor substrate is insufficient when the screen plate is separated from the silicon substrate.

  The present invention has been made in view of the above-described conventional problems. A semiconductor substrate passivation film having a desired shape can be formed by a simple method, has excellent storage stability, suppresses printing unevenness, and is excellent. It is an object of the present invention to provide a composition for forming a semiconductor substrate passivation film that exhibits coating film uniformity. Another object of the present invention is to provide a semiconductor substrate with a passivation film and a solar cell element using the composition for forming a semiconductor substrate passivation film. Furthermore, this invention makes it a subject to provide the manufacturing method of the semiconductor substrate with a passivation film using this composition for formation of a semiconductor substrate passivation film.

Specific means for solving the above problems are as follows.
<1> A composition for forming a semiconductor substrate passivation film, comprising an organoaluminum compound represented by the following general formula (I) and at least one selected from a fluorine-based surfactant and a silicone-based surfactant.

In the formula, each R ¹ independently represents an alkyl group having 1 to 8 carbon atoms. n represents an integer of 0 to 3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

<2> The composition for forming a semiconductor substrate passivation film according to <1>, wherein in the general formula (I), each R ¹ is independently an alkyl group having 1 to 4 carbon atoms.

<3> In the above general formula (I), in the above <1> or <2>, n is an integer of 1 to 3, and R ⁴ is independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The composition for forming a semiconductor substrate passivation film as described.

<4> The fluorine-containing surfactant is contained, and the fluorine-containing surfactant is at least one selected from an oligomer-type fluorine-containing surfactant and an active energy ray-curable fluorine-containing surfactant. The composition for forming a semiconductor substrate passivation film according to any one of 1> to <3>.

<5> The above-mentioned silicone surfactant, wherein the silicone surfactant is at least one selected from side chain type silicone oil, one-end type silicone oil, and both-end type silicone oil The composition for forming a semiconductor substrate passivation film according to any one of> to <4>.

<6> The composition for forming a semiconductor substrate passivation film according to any one of <1> to <5>, including the silicone-based surfactant, wherein the silicone-based surfactant is a silane coupling agent. object.

<7> The composition for forming a semiconductor substrate passivation film according to any one of <1> to <6>, further including a resin.

<8> The composition for forming a semiconductor substrate passivation film according to any one of <1> to <7>, further including a compound represented by the following general formula (II).

<9> The semiconductor substrate according to any one of <1> to <8>, wherein a total content of the fluorine-based surfactant and the silicone-based surfactant is 0.01% by mass to 10% by mass. A composition for forming a passivation film.

<10> a semiconductor substrate, and a fired product layer of the composition for forming a semiconductor substrate passivation film according to any one of <1> to <9> provided on the entire surface or a part of the semiconductor substrate; A semiconductor substrate with a passivation film.

<11> A step of forming a composition layer by applying the composition for forming a semiconductor substrate passivation film according to any one of <1> to <9> to the entire surface or a part of the semiconductor substrate;
Baking the composition layer to form a passivation film;
A method for manufacturing a semiconductor substrate with a passivation film, comprising:

<12> a semiconductor substrate in which a p-type layer and an n-type layer are pn-junction;
A fired product layer of the composition for forming a semiconductor substrate passivation film according to any one of <1> to <9> provided on the entire surface or a part of the semiconductor substrate;
An electrode disposed on the p-type layer or n-type layer of the semiconductor substrate;
A solar cell element having

  According to the present invention, it is possible to form a semiconductor substrate passivation film having a desired shape by a simple method, forming a semiconductor substrate passivation film that has excellent storage stability, suppresses printing unevenness, and exhibits good coating uniformity. A composition can be provided. Moreover, this invention can provide the semiconductor substrate with a passivation film and solar cell element which used this composition for semiconductor substrate passivation film formation. Furthermore, this invention can provide the manufacturing method of the semiconductor substrate with a passivation film using this semiconductor substrate passivation film formation composition.

It is sectional drawing which shows typically an example of the manufacturing method of the solar cell element which has the semiconductor substrate passivation film concerning this embodiment. It is sectional drawing which shows typically another example of the manufacturing method of the solar cell element which has the semiconductor substrate passivation film concerning this embodiment. It is sectional drawing which shows typically an example of the back surface electrode type solar cell element which has the semiconductor substrate passivation film concerning this embodiment.

  In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. . In the present specification, a numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, in the present specification, the content of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. Means.

<Composition for forming a semiconductor substrate passivation film>
The composition for forming a semiconductor substrate passivation film of the present invention is at least one selected from at least one organoaluminum compound represented by the following general formula (I), a fluorine-based surfactant, and a silicone-based surfactant. And including. The composition for forming a semiconductor substrate passivation film may further contain other components as necessary.

In the formula, each R ¹ independently represents an alkyl group having 1 to 8 carbon atoms. n represents an integer of 0 to 3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Here, when there are a plurality of any of R ^{1 to} R ⁴ , X ² and X ³ , the plurality of groups represented by the same symbol may be the same or different.

  The composition for forming a semiconductor substrate passivation film of the present invention is applied to a semiconductor substrate to form a composition layer having a desired shape, and this is fired to form a passivation film having an excellent passivation effect in a desired shape. Can be formed. The method of the present invention is a simple and highly productive method that does not require a vapor deposition apparatus or the like. Further, the passivation film can be formed in a desired shape without requiring a complicated process such as mask processing. Moreover, since the composition for forming a semiconductor substrate passivation film contains a specific organoaluminum compound, the occurrence of problems such as gelation is suppressed and the storage stability with time is excellent.

  In this specification, the passivation effect of a semiconductor substrate is obtained by reflecting the effective lifetime of minority carriers in a semiconductor substrate provided with a semiconductor substrate passivation film using a device such as WT-2000PVN manufactured by Nippon Semilab Co., Ltd. It can be evaluated by measuring by the method.

Here, the effective lifetime τ is expressed by the following equation (A) by the bulk lifetime τ _b inside the semiconductor substrate and the surface lifetime τ _s of the semiconductor substrate surface. When the surface state density on the surface of the semiconductor substrate is small, τ _s becomes long, resulting in a long effective lifetime τ. Further, even if defects such as dangling bonds in the semiconductor substrate are reduced, the bulk lifetime τ _b is increased and the effective lifetime τ is increased. That is, by measuring the effective lifetime τ, the interface characteristics of the passivation film / semiconductor substrate and the internal characteristics of the semiconductor substrate such as dangling bonds can be evaluated.
1 / τ = 1 / τ _b + 1 / τ _s (A)
Note that the longer the effective lifetime, the slower the recombination rate of minority carriers. Moreover, conversion efficiency improves by comprising a solar cell element using the semiconductor substrate with a long effective lifetime.

(Organic aluminum compound)
The composition for forming a semiconductor substrate passivation film contains at least one organoaluminum compound represented by the general formula (I) (hereinafter sometimes referred to as “specific organoaluminum compound”). The specific organoaluminum compound includes compounds called aluminum alkoxide, aluminum chelate and the like, and preferably has an aluminum chelate structure in addition to the aluminum alkoxide structure. Further, as described in Nippon Seramikkusu Kyokai Gakujitsu Ronbunshi, 97 (1989) 369-399, the organoaluminum compound is converted to aluminum oxide (Al ₂ O ₃ ) by firing treatment.

The inventors consider the reason why a passivation film having an excellent passivation effect can be formed when the composition for forming a semiconductor substrate passivation film contains the organoaluminum compound represented by the general formula (I) as follows. ing. However, the present invention is not limited to the following reasons.
Aluminum oxide formed by firing the semiconductor passivation film-forming composition of the present invention containing the specific organoaluminum compound is likely to be in an amorphous state, and a four-coordinate aluminum oxide layer is formed near the interface with the semiconductor substrate. It is thought that it can have a large negative fixed charge. This large negative fixed charge generates an electric field in the vicinity of the interface of the semiconductor substrate, so that the concentration of minority carriers can be reduced, and as a result, the carrier recombination rate at the interface can be suppressed. Therefore, it is considered that the composition for forming a semiconductor passivation film of the present invention containing a specific organoaluminum compound can form a passivation film having an excellent passivation effect.

Here, the state of the tetracoordinated aluminum oxide layer, which is a cause of negative fixed charges on the surface of the semiconductor substrate, is obtained by measuring the cross section of the semiconductor substrate by electron energy loss spectroscopy using a scanning transmission electron microscope (STEM). The binding mode can be examined by analysis of (EELS, Electron Energy Loss Spectroscopy). Tetracoordinate aluminum oxide is considered to have a structure in which the center of silicon dioxide (SiO ₂ ) is isomorphously substituted from silicon to aluminum, and is formed as a negative charge source at the interface between silicon dioxide and aluminum oxide like zeolite and clay. It has been known.

The state of the formed aluminum oxide can be confirmed by measuring an X-ray diffraction spectrum (XRD, X-ray diffraction). For example, it can be confirmed that the XRD has an amorphous structure by not showing a specific reflection pattern. The negative fixed charge of aluminum oxide can be evaluated by the CV method (Capacitance Voltage measurement). However, for the aluminum oxide fired layer formed from the semiconductor substrate passivation film forming composition of the present invention, the surface state density obtained from the CV method is the same as that of the aluminum oxide layer formed by ALD or CVD method. In some cases, the value may be large. However, the passivation film formed from the composition for forming a semiconductor substrate passivation film of the present invention has a large electric field effect and a low minority carrier concentration, resulting in a long surface lifetime τ _s . Therefore, the surface state density is not a relative problem.

In general formula (I), each R ¹ independently represents an alkyl group having 1 to 8 carbon atoms, and preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by R ¹ may be linear or branched. Specific examples of the alkyl group represented by R ¹ include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, hexyl group, octyl group, and ethylhexyl group. Etc. Among them, the alkyl group represented by R ¹ is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms from the viewpoint of storage stability and a passivation effect, and is an unsubstituted alkyl group having 1 to 4 carbon atoms. More preferably.

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

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

Among these, from the viewpoint of storage stability and a passivation effect, R ² and R ³ are each independently preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms, and preferably a hydrogen atom or 1 to 4 carbon atoms. The unsubstituted alkyl group is more preferable.
R ⁴ is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms from the viewpoint of storage stability and a passivation effect, and is a hydrogen atom or an unsubstituted alkyl group having 1 to 4 carbon atoms. More preferably.

In the organoaluminum compound represented by the general formula (I), n is 1 to 3 and R ⁴ is independently a hydrogen atom or an alkyl having 1 to 4 carbon atoms from the viewpoint of suppressing reactivity by chelation. It is preferably a compound that is a group.

In addition, the organoaluminum compound represented by the general formula (I) is a compound in which n is 0 and R ¹ is independently an alkyl group having 1 to 4 carbon atoms from the viewpoint of storage stability and a passivation effect. N is 1 to 3, R ¹ is independently an alkyl group having 1 to 4 carbon atoms, at least one of X ² and X ³ is an oxygen atom, and R ² and R ³ are each It is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁴ is at least one selected from the group consisting of a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. More preferably, a compound in which n is 0 and R ¹ is each independently an unsubstituted alkyl group having 1 to 4 carbon atoms; and n is 1 to 3 and each R ¹ is independently carbon. An unsubstituted alkyl group having 1 to 4 carbon atoms, at least one of X ² and X ³ is an oxygen atom, and R ² or R ³ bonded to the oxygen atom is an alkyl group having 1 to 4 carbon atoms; When X ² or X ³ is a methylene group, R ² or R ³ bonded to the methylene group is a hydrogen atom, and at least one selected from the group consisting of compounds wherein R ⁴ is a hydrogen atom.

  Specific examples of the aluminum trialkoxide, which is an organoaluminum compound represented by the general formula (I) and n is 0, include trimethoxyaluminum, triethoxyaluminum, triisopropoxyaluminum, trisec-butoxyaluminum, monosec-butoxy -Diisopropoxyaluminum, tritert-butoxyaluminum, tri-n-butoxyaluminum and the like can be mentioned.

  Specific examples of the organoaluminum compound represented by the general formula (I) where n is 1 to 3 include aluminum ethyl acetoacetate diisopropylate (ethyl acetoacetate aluminum diisopropylate), aluminum tris (ethyl acetoacetate). And aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum tris (acetylacetonate), and the like.

  As the organoaluminum compound represented by the general formula (I) and n of 1 to 3, a prepared product or a commercially available product may be used. Examples of commercially available products include Kawaken Fine Chemical Co., Ltd. trade names, ALCH, ALCH-TR, ALCH-TR, aluminum chelate D, alkylate A, and the like.

The organoaluminum compound represented by the general formula (I) and n is 1 to 3 can be prepared by mixing the aluminum trialkoxide and a compound having a specific structure having two carbonyl groups.
When the aluminum trialkoxide and a compound having a specific structure having two carbonyl groups are mixed, at least a part of the alkoxide group of the aluminum trialkoxide is substituted with the compound having the specific structure to form an aluminum chelate structure. At this time, if necessary, a solvent may be present, or heat treatment or addition of a catalyst may be performed. By replacing at least a part of the aluminum alkoxide structure with the aluminum chelate structure, the stability of the organoaluminum compound to hydrolysis and polymerization reaction is improved, and the storage stability of the composition for forming a semiconductor substrate passivation film containing the same is improved. More improved.

  The compound having a specific structure having two carbonyl groups is preferably at least one selected from the group consisting of a β-diketone compound, a β-ketoester compound, and a malonic acid diester from the viewpoint of storage stability. Specific examples of the compound having a specific structure having the 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 Β-diketone compounds such as methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, isobutyl acetoacetate, butyl acetoacetate, tert-butyl acetoacetate, pentyl acetoacetate, hexyl acetoacetate, n-octyl acetoacetate , Heptyl acetoacetate, 3-pentyl acetoacetate, ethyl 2-acetylheptanoate, 2-butylacetate Ethyl acetate, ethyl 4,4-dimethyl-3-oxovalerate, ethyl 4-methyl-3-oxovalerate, ethyl 2-ethylacetoacetate, ethyl hexylacetoacetate, methyl 4-methyl-3-oxovalerate, Isopropyl acetoacetate, ethyl 3-oxohexanoate, ethyl 3-oxovalerate, methyl 3-oxovalerate, methyl 3-oxohexanoate, ethyl 2-methylacetoacetate, ethyl 3-oxoheptanoate, 3-oxoheptanoic acid Β-ketoester compounds such as methyl, methyl 4,4-dimethyl-3-oxovalerate; dimethyl malonate, diethyl malonate, dipropyl malonate, diisopropyl malonate, dibutyl malonate, di-tert-butyl malonate, malon Dihexyl acid, tert-butylethyl malonate, diethyl methylmalonate, Chirumaron diethyl, isopropyl diethyl malonate, butyl diethyl malonate, sec- butyl diethyl malonate, isobutyl diethyl malonate, and the like malonic acid diester, such as 1-methyl butyl diethylmalonate.

  When the specific organoaluminum compound has an aluminum chelate structure, the number of aluminum chelate structures is not particularly limited as long as it is 1 to 3. Among these, 1 or 3 is preferable from the viewpoint of storage stability, and 1 is more preferable from the viewpoint of solubility. The number of aluminum chelate structures can be controlled, for example, by appropriately adjusting the ratio of mixing the aluminum trialkoxide and a compound capable of forming a chelate with aluminum. Moreover, you may select suitably the compound which has a desired structure from a commercially available aluminum chelate compound.

  Of the organoaluminum compounds represented by the general formula (I), from the viewpoint of reactivity during firing and storage stability as a composition, specifically, an organoaluminum compound in which n is 1 to 3 may be used. Preferably, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), aluminum monoacetylacetonate bis (ethyl acetoacetate), aluminum tris (acetylacetonate) are more preferably used, and ethyl acetoacetate aluminum diisopropylate is more preferable. More preferably, the rate is used.

  The presence of the aluminum chelate structure in the specific organoaluminum compound can be confirmed by a commonly used analytical method. For example, it can be confirmed using an infrared spectrum, a nuclear magnetic resonance spectrum, a melting point, or the like.

  The content of the specific organoaluminum compound contained in the composition for forming a semiconductor substrate passivation film can be appropriately selected as necessary. For example, from the viewpoint of storage stability and a passivation effect, the composition for forming a semiconductor substrate passivation film is preferably 1% by mass to 70% by mass, more preferably 3% by mass to 60% by mass. It is more preferable that it is mass%-50 mass%, and it is especially preferable that it is 10 mass%-30 mass%.

  The specific organoaluminum compound may be liquid or solid and is not particularly limited. Passivation formed by being a compound with good stability at room temperature, good stability or solubility at room temperature, and good solubility or dispersibility from the viewpoint of passivation effect and storage stability The uniformity of the film is further improved, and a desired passivation effect can be stably obtained.

(Fluorine-based surfactant, silicone-based surfactant)
The composition for forming a semiconductor substrate passivation film of the present invention contains at least one of a fluorine-based surfactant and a silicone-based surfactant in order to suppress printing unevenness and improve coating film uniformity. It has been found that the composition for forming a semiconductor substrate passivation film does not lower the passivation effect even if it contains a fluorine-based surfactant or a silicone-based surfactant.

  The cause of the occurrence of uneven printing on the semiconductor substrate and the coating film uniformity of the semiconductor substrate passivation film forming composition is that the surface energy of the semiconductor substrate passivation film forming composition is larger than the surface energy of the semiconductor substrate. is there. In the composition for forming a semiconductor substrate passivation film of the present invention, the surface energy is adjusted by blending a fluorine-based surfactant or a silicone-based surfactant having a high surface energy reducing ability, and the above problems are improved. it is conceivable that.

Although there is no restriction | limiting in particular as a fluorine-type surfactant, The thing containing the perfluoroalkyl group which expresses a surface energy reduction effect more is preferable, an oligomer type fluorine-type surfactant or an active energy ray hardening type fluorine-type interface is preferable. More preferred is an activator.
The oligomer type fluorosurfactant has a group containing a perfluoroalkyl group in the side chain of the oligomer, specifically, Megafac F-430, F-477, F-552, F-553, manufactured by DIC, F-554, F-555, F-556, F-557, F-558, F-559, F-561, F-562, R-40, R-41, TF-1540, TF-1760, etc. be able to.

  The active energy ray-curable fluorosurfactant has a perfluoroalkyl group and a reactive double bond-containing group in the oligomer. Specifically, Megafac RS-72-K and RS-75 manufactured by DIC are used. RS-76-E, RS-76-NS, and the like.

As the silicone-based surfactant, a compound containing a silicone chain or a silane coupling agent is preferable.
Although the silicone chain of the compound having a silicone chain is not as effective in reducing the surface energy as the perfluoroalkyl group of the fluorosurfactant, it has a certain viscosity, so the composition for forming a semiconductor substrate passivation film and the semiconductor substrate Printing unevenness and coating film uniformity can be improved. As the silicone-based surfactant, side chain type silicone oil, one-end type silicone oil, or both-end type silicone oil is preferable.

  The side chain type silicone oil is a modified silicone oil having a specific functional group in the side chain of the silicone chain as the main chain, specifically, amino-modified KF-868, KF-865, KF- manufactured by Shin-Etsu Chemical Co., Ltd. 864, KF-859, KF-393, KF-860, KF-880, KF-8004, KF-8002, KF-8005, KF-867, KF-869, KF-861, KF-877; epoxy modified KF- 101, KF-102, KF-1001, KF-1002; mercapto-modified KF-2001, KF-2004; polyether-modified KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A , KF-945, KF-640, KF-642, KF-643, KF-6020, KF-6011, KF-6 12, KF-6015, KF-6017; fluoroalkyl-modified FL-5, FL-100-100cs, FL-100-450cs, FL-100-1000cs, FL-100-10000cs; long-chain alkyl-modified KF-412, KF -413, KF-414, KF-145, KF-4003, KF-4701, KF-4917, KF-7235B; higher fatty acid ester-modified KF-910; higher fatty acid-containing modified KF-3935; phenyl-modified KF-50-100cs , KF-50-300cs, KF-50-1000cs, KF-50-3000cs, KF-53, KF-54 and the like.

  One-end type silicone oil is a modified silicone oil having a specific functional group at one end of a silicone chain that is a main chain. Specifically, epoxy-modified X-22-173DX manufactured by Shin-Etsu Chemical Co., Ltd .; carbinol-modified X-22-170BX, X-22-170DX; diol-modified X-22-176DX, X-22-176GX-A; methacryl-modified X-22-174ASX, X-22-174DX, X-22-2426, X- 22-2475; carboxyl-modified X-22-3710 and the like.

  The both-end type silicone oil is a modified silicone oil having specific functional groups at both ends of the silicone chain that is the main chain, specifically, amino-modified PAM-E, KF-8010, X manufactured by Shin-Etsu Chemical Co., Ltd. -22-161A, X-22-161B, KF-8012, KF-8008, X-22-1660B-3, X-22-9409; epoxy-modified X-22-163, KF-105, X-22-163A , X-22-163B, X-22-163C; cycloaliphatic epoxy modified X-22-169AS, X-22-169B; carbinol modified X-22-160AS, KF-6001, KF-6002, KF-6003 Methacryl-modified X-22-164, X-22-164AS, X-22-164A, X-22-164B, X-22-164C, X-22 164E; polyether modified X-22-4952, X-22-4272, X-22-6266, KF-6004; mercapto modified X-22-167B; carboxyl modified X-22-162C; phenol modified X-22-1821 Silanol modified X-21-5841, KF-9701; polyether methoxy modified KF-889, and the like.

The silane coupling agent can directly react with the semiconductor substrate to modify the surface and improve printing unevenness and coating film uniformity of the semiconductor substrate passivation film forming composition.
Specific examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxy. Propyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxy Silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2- (amino Til) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl- N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3 -Ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane and the like.

  Of the fluorosurfactants or silicone surfactants, from the viewpoint of improving wettability with a semiconductor substrate, it is preferable to use a fluorosurfactant, and to use an active energy ray-curable fluorosurfactant. More preferably, it is more preferable to use Megafac RS-72-K, RS-75, RS-76-E, and RS-76-NS manufactured by DIC.

  The total content of the fluorine-based surfactant and the silicone-based surfactant in the composition for forming a semiconductor substrate passivation film is preferably 0.01% by mass to 10% by mass, and 0.02% by mass to 8% by mass. %, More preferably 0.05% by mass to 7% by mass.

(resin)
The composition for forming a semiconductor substrate passivation film may further contain a resin. By including the resin, the shape stability of the composition layer formed by applying the composition for forming a semiconductor substrate passivation film on the semiconductor substrate is further improved, and the passivation film is formed in the region where the composition layer is formed. In addition, it can be selectively formed in a desired shape.

  The kind of the resin is not particularly limited. Among these, when applying the composition for forming a semiconductor substrate passivation film on a semiconductor substrate, a resin capable of adjusting the viscosity within a range in which a good pattern can be formed is preferable. Specific examples of the resin include polyvinyl alcohol, polyacrylamides, polyvinylamides, polyvinylpyrrolidone, polyethylene oxides, polysulfonic acid, polyacrylamide alkylsulfonic acid, cellulose, cellulose ethers, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl cellulose, and the like. Cellulose derivatives, gelatin and gelatin derivatives, starch and starch derivatives, sodium alginate and sodium alginate derivatives, xanthan and xanthan derivatives, gua and guar derivatives, scleroglucan and scleroglucan derivatives, tragacanth and tragacanth derivatives, dextrin and dextrin derivatives ( (Meth) acrylic acid resin, (meth) acrylic acid ester resin (for example, alkyl (meta Acrylate resins, dimethylaminoethyl (meth) acrylate resin, etc.), butadiene resins, styrene resins, siloxane resins and the like can be mentioned a copolymer thereof. These resins are used alone or in combination of two or more.

Among these resins, from the viewpoint of storage stability and pattern formation, it is preferable to use a neutral resin having no acidic or basic functional group, and even when the content is small, viscosity and From the viewpoint of adjusting the thixotropy, it is more preferable to use a cellulose derivative.
The molecular weight of these resins is not particularly limited, and is preferably adjusted appropriately in view of the desired viscosity as the composition for forming a semiconductor substrate passivation film. 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 formation. In addition, the weight average molecular weight of resin is calculated | required by converting using the analytical curve of a standard polystyrene from molecular weight distribution measured using GPC (gel permeation chromatography).

These resins are used alone or in combination of two or more.
When the composition for forming a semiconductor substrate passivation film contains a resin, the content of the resin in the composition for forming a semiconductor substrate passivation film can be appropriately selected as necessary. For example, the resin content in the composition for forming a semiconductor substrate passivation film is preferably 0.1% by mass to 30% by mass. From the viewpoint of developing thixotropy that facilitates pattern formation, the content is more preferably 0.2% by mass to 25% by mass, and 0.25% by mass to 20% by mass. More preferably, it is especially preferable that it is 0.25 mass%-10 mass%.

  Moreover, the content ratio of the specific organoaluminum compound and the resin in the composition for forming a semiconductor substrate passivation film in the case of containing a resin can be appropriately selected as necessary. Among these, from the viewpoint of pattern formation and storage stability, the content ratio of the resin to the specific organoaluminum compound (resin / specific organoaluminum compound) is preferably 0.001 to 1000, and preferably 0.01 to 100. Is more preferable, and it is still more preferable that it is 0.1-1.

(High boiling point material)
Further, the composition for forming a semiconductor substrate passivation film of the present invention is a material having a high boiling point (high boiling point material) that does not need to be easily vaporized and degreased during heating as a material replacing the resin or in combination with the resin. It may be used. In particular, the high-boiling material is preferably a high-viscosity material that can maintain a printed shape after printing and coating, and examples of the material that satisfies these include isobornylcyclohexanol represented by the following general formula (II).

  The isobornylcyclohexanol represented by the general formula (II) is commercially available as “Telsolve MTPH” (trade name, manufactured by Nippon Terpene Chemical Co., Ltd.). Isobornyl cyclohexanol has a high boiling point of 308 ° C. to 318 ° C., and can be eliminated by vaporization rather than degreasing by firing like a resin binder during heating. For this reason, most of the solvent and isobornyl cyclohexanol in the composition can be removed in the drying step after coating on the semiconductor substrate.

  When the composition for forming a semiconductor substrate passivation film contains a high-boiling material, the content of the high-boiling material is preferably 3% by mass to 95% by mass in the total mass of the composition for forming a semiconductor substrate passivation film. More preferably, it is 5 mass%-90 mass%, and it is especially preferable that it is 7 mass%-80 mass%.

(solvent)
The composition for forming a semiconductor substrate passivation film may further contain a solvent. When the composition for forming a semiconductor substrate passivation film contains a solvent, the adjustment of the viscosity becomes easier, the applicability is further improved, and a more uniform fired layer can be formed. The solvent is not particularly limited and can be appropriately selected as necessary. Among them, a solvent capable of dissolving the specific organoaluminum compound and the resin to give a uniform solution is preferable, and more preferably containing at least one organic solvent.

  Specific examples of the solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-i-propyl ketone, methyl-n-butyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, and methyl-n-hexyl ketone. , Ketone solvents such as diethyl ketone, dipropyl ketone, di-i-butyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone; diethyl ether, methyl ethyl ether, Methyl-n-propyl ether, di-i-propyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene Recall di-n-propyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl n-propyl ether, diethylene glycol methyl n-butyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di- n-butyl ether, diethylene glycol methyl-n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl-n-butyl ether, triethylene glycol di-n-butyl ether, triethylene Glico Rumethyl-n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene 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 glyco 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, tetra Propylene glycol methyl-n-butyl ether, tetrapropylene Ether solvents such as glycol di-n-butyl ether, tetrapropylene glycol methyl-n-hexyl ether, tetrapropylene glycol di-n-butyl ether; methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-acetate Butyl, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2- (2-butoxyethoxy acetate) ) Ethyl, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl acetate Ether, dipropylene glycol ethyl ether, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, lactic acid Ethyl, n-butyl lactate, n-amyl lactate, ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether Ester solvents such as acetate, propylene glycol propyl ether acetate, γ-butyrolactone, γ-valerolactone; acetonitrile, N-methyl Aprotic polarities such as rupyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide Solvent: methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i-pentanol, 2-methylbutanol, sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-octanol, 2-ethylhexanol, sec-octane Tanol, n-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, benzyl alcohol, ethylene glycol, 1, Alcohol solvents such as 2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 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 Glycol monomers such as butyl ether, diethylene glycol mono-n-hexyl ether, ethoxy triglycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether Examples include ether solvents; terpene solvents such as α-terpinene, α-terpineol, myrcene, alloocimene, limonene, dipentene, α-pinene, β-pinene, terpineol, carvone, oximene, and ferrandrene; water and the like. These are used singly or in combination of two or more.

  Above all, the solvent preferably contains at least one selected from the group consisting of a terpene solvent, an ester solvent, and an alcohol solvent, from the viewpoint of imparting properties to a semiconductor substrate and pattern forming properties. More preferably, at least one selected from the group consisting of:

  The content of the solvent in the case of using the solvent for the composition for forming a semiconductor substrate passivation film is determined in consideration of the imparting property, the pattern forming property, and the storage stability. For example, the content of the solvent is preferably 1% by mass to 95% by mass in the composition for forming a semiconductor substrate passivation film, preferably 2% by mass to 90% by mass, from the viewpoint of the impartability of the composition and the pattern formability. It is more preferable that

(Other additives)
The composition for forming a semiconductor substrate passivation film may contain an acidic compound or a basic compound. When an acidic compound or a basic compound is contained, from the viewpoint of storage stability, the content of the acidic compound or the basic compound is preferably 1% by mass or less in the composition for forming a semiconductor substrate passivation film, More preferably, it is 0.1 mass% or less.
Examples of the acidic compound include Bronsted acid and Lewis acid, and specific examples include inorganic acids such as hydrochloric acid and nitric acid; organic acids such as acetic acid. Examples of basic compounds include Bronsted bases and Lewis bases. Specifically, inorganic bases such as alkali metal hydroxides and alkaline earth metal hydroxides, and organic bases such as trialkylamines and pyridines. And so on.

(Physical property value)
The viscosity of the composition for forming a semiconductor substrate passivation film is not particularly limited, and can be appropriately selected depending on a method for applying the composition to the semiconductor substrate. For example, the viscosity of the composition for forming a semiconductor substrate passivation film may be 0.01 Pa · s to 10000 Pa · s. Among these, from the viewpoint of pattern formability, it is preferably 0.1 Pa · s to 1000 Pa · s. The viscosity is measured at 25 ° C. and a shear rate of 1.0 s ⁻¹ using a rotary shear viscometer.

The shear viscosity of the composition for forming a semiconductor substrate passivation film is not particularly limited, and preferably has thixotropy. Among them from the viewpoints of pattern formability, thixotropic ratio calculated by dividing the shear viscosity eta ₁ at shear viscosity eta ₂ at a shear rate of ^{10s -1} at a shear rate of ^{_{1.0s -1 (η 1 / η 2}} ) is 1. It is preferable that it is 05-100, and it is more preferable that it is 1.1-50.
The shear viscosity is measured at a temperature of 25 ° C. using a rotary shear viscometer equipped with a cone plate (diameter 50 mm, cone angle 1 °).
On the other hand, when the semiconductor substrate passivation film-forming composition containing high-boiling material in place of the resin, from the viewpoint of pattern formability, shear viscosity shear viscosity eta ₁ at a shear rate of 1.0 s ^-1 at a shear rate of 1000 s ^-1 preferably thixotropic ratio calculated by dividing _{η 3 (η 1 / η 3} ) is 1.05 to 100, more preferably from 1.1 to 50.

  The components contained in the composition for forming a semiconductor substrate passivation film, and the content of each component are subjected to thermal analysis such as TG / DTA, spectrum analysis such as NMR and IR, and chromatographic analysis such as HPLC and GPC. Can be confirmed.

(Method for producing composition for forming a semiconductor substrate passivation film)
There is no restriction | limiting in particular in the manufacturing method of the said composition for semiconductor substrate passivation film formation. For example, it can be produced by mixing an organoaluminum compound, at least one selected from a fluorine-based surfactant and a silicone-based surfactant and, if necessary, a solvent by a commonly used mixing method. Alternatively, at least one selected from a fluorine-based surfactant and a silicone-based surfactant may be dissolved in a solvent and then mixed with an organoaluminum compound.
Furthermore, the specific organoaluminum compound may be prepared by mixing aluminum alkoxide and a compound capable of forming a chelate with aluminum. At that time, a solvent may be appropriately used or heat treatment may be performed. The specific organoaluminum compound thus prepared and at least one selected from a fluorosurfactant and a silicone surfactant or at least one selected from a fluorosurfactant and a silicone surfactant A composition for forming a semiconductor substrate passivation film may be produced by mixing with a solution containing it.

(Use)
The passivation film on the semiconductor substrate of the present invention is a composition for forming a semiconductor substrate passivation film that is preferably used for forming a passivation film on a semiconductor substrate. In addition, the passivation film on the semiconductor substrate of the present invention can be more suitably used when the semiconductor substrate is a semiconductor substrate for solar cells.

<Semiconductor substrate with passivation film>
The semiconductor substrate with a passivation film of the present invention includes a semiconductor substrate and a fired product layer of the composition for forming a semiconductor substrate passivation film provided on the entire surface or a part of the semiconductor substrate. The semiconductor substrate with a passivation film exhibits an excellent passivation effect by having a passivation film that is a layer made of a fired product of the composition for forming a semiconductor substrate passivation film.

The semiconductor substrate to which the composition for forming a semiconductor substrate passivation film is applied is not particularly limited and can be appropriately selected from those usually used according to the purpose. The semiconductor substrate is not particularly limited as long as silicon, germanium, or the like is doped with p-type impurities or n-type impurities. Of these, a silicon substrate is preferable. The semiconductor substrate may be a p-type semiconductor substrate or an n-type semiconductor substrate. Among these, from the viewpoint of the passivation effect, it is preferable that the surface on which the passivation film is formed is a semiconductor substrate that is a p-type layer. Even if the p-type layer on the semiconductor substrate is a p-type layer derived from the p-type semiconductor substrate, the p-type layer is formed on the n-type semiconductor substrate or the p-type semiconductor substrate as a p-type diffusion layer or a p ⁺ -type diffusion layer. It may be.
The thickness of the 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, and preferably 75 μm to 750 μm.

  The thickness of the passivation film formed on the semiconductor substrate is not particularly limited and can be appropriately selected according to the purpose. For example, it is preferably 2 nm to 1 μm, preferably 3 nm to 0.9 μm, and more preferably 4 nm to 0.8 μm.

  The semiconductor substrate with a passivation film can be applied to a solar cell element, a light emitting diode element or the like. For example, the solar cell element excellent in conversion efficiency can be obtained by applying to a solar cell element.

<Method of manufacturing semiconductor substrate with passivation film>
The method for producing a semiconductor substrate with a passivation film according to the present invention comprises a step of forming a composition layer by applying the composition for forming a semiconductor substrate passivation film on the entire surface or a part of the semiconductor substrate, and the composition layer comprising: And a step of forming a passivation film by baking treatment. The manufacturing method may further include other steps as necessary.
By using the composition for forming a semiconductor substrate passivation film, a passivation film having an excellent passivation effect can be formed into a desired shape by a simple method.

  As the semiconductor substrate to which the composition for forming a semiconductor substrate passivation film is applied, those described in the above-mentioned semiconductor substrate with a passivation film can be used.

  The method for manufacturing a semiconductor substrate with a passivation film preferably further includes a step of applying an alkaline aqueous solution on the semiconductor substrate before the step of forming the composition layer. That is, it is preferable to wash the surface of the semiconductor substrate with an alkaline aqueous solution before applying the composition for forming a semiconductor substrate passivation film on the semiconductor substrate. By washing with an alkaline aqueous solution, organic substances, particles, and the like present on the surface of the semiconductor substrate can be removed, and the passivation effect is further improved.

  As a method of cleaning with an alkaline aqueous solution, generally known RCA cleaning and the like can be exemplified. For example, the organic substance and particles can be removed and washed by immersing the semiconductor substrate in a mixed solution of aqueous ammonia and hydrogen peroxide and treating at 60 ° C. to 80 ° C. The washing time is preferably 10 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes.

There is no particular limitation on the method for forming the composition layer by applying the composition for forming a semiconductor substrate passivation film on a semiconductor substrate. For example, a method of applying the composition for forming a semiconductor substrate passivation film on a semiconductor substrate using a known coating method can be exemplified.
Specific examples include immersion method, printing method, spin method, brush coating, spray method, doctor blade method, roll coater method, and ink jet method. Among these, from the viewpoint of pattern formability, various printing methods, ink jet methods, and the like are preferable.

  The application amount of the composition for forming a semiconductor substrate passivation film can be appropriately selected according to the purpose. For example, the thickness of the passivation film to be formed can be appropriately adjusted so as to be a desired film thickness described later.

A semiconductor substrate passivation film can be formed on a semiconductor substrate by baking a composition layer formed of the composition for forming a semiconductor substrate passivation film to form a fired product layer derived from the composition layer. it can.
The firing conditions of the composition layer are not particularly limited as long as the organoaluminum compound contained in the composition layer can be converted into aluminum oxide (Al ₂ O ₃ ) that is the fired product. Among these, it is preferable that the firing conditions are such that an amorphous Al ₂ O ₃ layer having no specific crystal structure can be formed. When the semiconductor substrate passivation film is composed of an amorphous Al ₂ O ₃ layer, the semiconductor substrate passivation film can effectively have a negative charge, and a more excellent passivation effect can be obtained. Specifically, the firing temperature is preferably 400 ° C to 900 ° C, more preferably 450 ° C to 800 ° C. The firing time can be appropriately selected according to the firing temperature and the like. For example, it can be 0.1 hours to 10 hours, and preferably 0.2 hours to 5 hours.

The thickness of the passivation film produced by the method for producing a semiconductor substrate with a passivation film is not particularly limited and can be appropriately selected according to the purpose. For example, it is preferably 2 nm to 1 μm, preferably 3 nm to 0.9 μm, and more preferably 4 nm to 0.8 μm.
The thickness of the formed passivation film is calculated as an arithmetic average value by measuring the thickness at three points by a conventional method using a stylus type step / surface shape measuring device (for example, manufactured by Ambios). The

  The method for manufacturing a semiconductor substrate with a passivation film includes: a composition layer comprising a composition for forming a semiconductor substrate passivation film, after the composition for forming a semiconductor substrate passivation film is applied and before the step of forming the passivation film by a baking process. You may further have the process of drying-processing. By including the step of drying the composition layer, a passivation film having a more uniform passivation effect can be formed.

  The step of drying the composition layer is not particularly limited as long as at least a part of the solvent that may be contained in the composition for forming a semiconductor substrate passivation film can be removed. The drying treatment can be, for example, a heat treatment at 30 ° C. to 250 ° C. for 1 minute to 60 minutes, and is preferably a heat treatment at 40 ° C. to 220 ° C. for 3 minutes to 40 minutes. The drying treatment may be performed under normal pressure or under reduced pressure.

<Solar cell element>
The solar cell element of the present invention includes a semiconductor substrate in which a p-type layer and an n-type layer are pn-junction, and a fired product of the composition for forming a semiconductor substrate passivation film provided on the entire surface or a part of the semiconductor substrate. A semiconductor substrate passivation film which is a layer, and electrodes disposed on at least one of the p-type layer and the n-type layer of the semiconductor substrate. The solar cell element may further include other components as necessary.
The said solar cell element is excellent in conversion efficiency by having the passivation film formed from the said composition for semiconductor substrate passivation film formation.

The surface of the semiconductor substrate on which the passivation film is provided may be a p-type layer or an n-type layer. Among these, a p-type layer is preferable from the viewpoint of conversion efficiency. Even if the p-type layer on the semiconductor substrate is a p-type layer derived from the p-type semiconductor substrate, the p-type layer is formed on the n-type semiconductor substrate or the p-type semiconductor substrate as a p-type diffusion layer or a p ⁺ -type diffusion layer. It may be.

The thickness of the semiconductor substrate is not particularly limited and can be appropriately selected according to the purpose. For example, the thickness may be 50 μm to 1000 μm, and preferably 75 μm to 750 μm. The thickness of the passivation film formed on the semiconductor substrate is not particularly limited, and can be appropriately selected according to the purpose. For example, the thickness is preferably 2 nm to 1 μm, more preferably 3 nm to 0.9 μm, and still more preferably 4 nm to 0.8 μm.
There is no restriction | limiting in the shape and magnitude | size of the said solar cell element. For example, it is preferable that one side is a square of 125 mm to 156 mm.

<Method for producing solar cell element>
The method for producing a solar cell element of the present invention includes a semiconductor substrate having a pn junction formed by joining a p-type layer and an n-type layer, and having an electrode on at least one of the p-type layer and the n-type layer. A step of forming the composition layer by applying the composition for forming a semiconductor substrate passivation film on one or both of the surfaces having the electrodes, and firing the composition layer to form a passivation film. Process. The method for manufacturing the solar cell element may further include other steps as necessary.

  By using the composition for forming a semiconductor substrate passivation film, a solar cell element having a semiconductor substrate passivation film having an excellent passivation effect and excellent in conversion efficiency can be produced by a simple method. Furthermore, the semiconductor substrate passivation film can be formed on the semiconductor substrate on which the electrodes are formed so as to have a desired shape, and the productivity of the solar cell element is excellent.

  A semiconductor substrate having a pn junction in which an electrode is disposed on at least one of a p-type layer and an n-type layer can be manufactured by a commonly used method. For example, it can be manufactured by applying an electrode forming paste such as a silver paste or an aluminum paste to a desired region of a semiconductor substrate and performing a baking treatment if necessary.

The surface of the semiconductor substrate on which the semiconductor substrate passivation film is provided may be a p-type layer or an n-type layer. Among these, a p-type layer is preferable from the viewpoint of conversion efficiency.
The details of the method for forming the semiconductor substrate passivation film by applying the composition for forming a semiconductor substrate passivation film are the same as the above-described method for manufacturing a semiconductor substrate with a passivation film, and the preferred embodiments are also the same.
The thickness of the semiconductor substrate passivation film formed on the semiconductor substrate is not particularly limited and can be appropriately selected depending on the purpose. The thickness is preferably 2 nm to 1 μm, preferably 3 nm to 0.9 μm, and more preferably 4 nm to 0.8 μm.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing an exemplary process for producing a solar cell element having a semiconductor substrate passivation film according to the present embodiment. However, this process diagram does not limit the present invention.

As shown in FIG. 1A, an n ⁺ -type diffusion layer 2 is formed in the vicinity of the surface of the p-type semiconductor substrate 1, and an antireflection film 3 is formed on the outermost surface. Examples of the antireflection film 3 include a silicon nitride film and a titanium oxide film. A surface protective film (not shown) such as silicon oxide may further exist between the antireflection film 3 and the p-type semiconductor substrate 1. Moreover, you may use the semiconductor substrate passivation film concerning this invention as a surface protective film.

Next, as shown in FIG. 1B, a material for forming the back electrode 5 such as an aluminum electrode paste is applied to a partial region of the back surface and then heat-treated to form the back electrode 5 and the p-type semiconductor substrate 1. Aluminum atoms are diffused therein to form the p ⁺ -type diffusion layer 4.

Next, as shown in FIG. 1C, the electrode 7 is applied to the light-receiving surface side and then heat-treated to form the surface electrode 7. By using those containing glass powder having a fire-through property as an electrode forming paste, reaches through the antireflective film 3, as shown in FIG. 1 (c), on the n ⁺ -type diffusion layer 2, the surface electrode 7 can be formed to obtain an ohmic contact.

  In FIG. 1, (b) and (c) are illustrated as separate steps, but the steps (b) and (c) may be combined into one step. Specifically, in (b) above, after a material for forming the back electrode 5 such as an aluminum electrode paste is applied to a partial area of the back surface, the light is received before the heat treatment for forming the back electrode 5 is performed. An electrode forming paste may be applied to the surface side, and heat treatment may be 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, and the process is simplified.

  Finally, as shown in FIG. 1 (d), a composition for forming a semiconductor substrate passivation film is applied on the p-type layer on the back surface other than the region where the back electrode 5 is formed to form a composition layer. The application can be performed by a coating method such as screen printing. The composition layer formed on the p-type layer is baked to form the semiconductor substrate passivation film 6. By forming the semiconductor substrate passivation film 6 formed from the composition for forming a semiconductor substrate passivation film on the p-type layer on the back surface, a solar cell element having excellent power generation efficiency can be manufactured.

  In the solar cell element manufactured by the manufacturing method including the manufacturing process shown in FIG. 1, the back electrode formed from aluminum or the like can have a point contact structure, and the warpage of the substrate can be reduced. Furthermore, by using the composition for forming a semiconductor substrate passivation film, a semiconductor substrate passivation film can be formed with excellent productivity only on the p-type layer other than the region where the electrodes are formed.

Further, FIG. 1D shows a method of forming a semiconductor substrate passivation film only on the back surface portion, but in addition to the back surface side of the semiconductor substrate 1, a composition for forming a semiconductor substrate passivation film is also applied to the side surface. A semiconductor substrate passivation film may be further formed on the side surface (edge) of the semiconductor substrate 1 by baking (not shown). Thereby, the solar cell element excellent in power generation efficiency can be manufactured.
Furthermore, the semiconductor substrate passivation film may be formed by applying and drying the composition for forming a semiconductor substrate passivation film of the present invention only on the side surface without forming the semiconductor substrate passivation film on the back surface portion. When the composition for forming a semiconductor substrate passivation film of the present invention is used in a place where there are many crystal defects such as side surfaces, the effect is particularly great.

  In FIG. 1, the semiconductor substrate passivation film is formed after the electrodes are formed. However, after the passivation film is formed, an electrode such as aluminum may be formed in a desired region by vapor deposition or the like.

FIG. 2 is a sectional view schematically showing another process example of a method for manufacturing a solar cell element having a semiconductor substrate passivation film according to the present embodiment. Specifically, FIG. 2 shows the heat treatment of the aluminum electrode paste after forming the p ⁺ type diffusion layer using the aluminum electrode paste or the p type diffusion layer forming composition capable of forming the p ⁺ type diffusion layer by thermal diffusion treatment. The process drawing including the process of removing the heat-treated product of the product or the p ⁺ -type diffusion layer forming composition will be described as a cross-sectional view. Examples of the p-type diffusion layer forming composition include a composition containing an acceptor element-containing substance and a glass component.

As shown in FIG. 2A, an n ⁺ -type diffusion layer 2 is formed in the vicinity of the surface of the p-type semiconductor substrate 1, and an antireflection film 3 is formed on the surface. Examples of the antireflection film 3 include a silicon nitride film and a titanium oxide film.

Next, as shown in FIG. 2B, the p ⁺ -type diffusion layer 4 is formed by applying a p ⁺ -type diffusion layer forming composition to a partial region of the back surface and then performing heat treatment. On the p ⁺ type diffusion layer 4, a heat treatment product 8 of a composition for forming a p ⁺ type diffusion layer is formed.
Here, an aluminum electrode paste may be used instead of the p-type diffusion layer forming composition. When an aluminum electrode paste is used, an aluminum electrode 8 is formed on the p ⁺ type diffusion layer 4.

Next, as shown in FIG. 2C, the heat treatment product 8 or the aluminum electrode 8 of the p-type diffusion layer forming composition formed on the p ⁺ -type diffusion layer 4 is removed by a technique such as etching.

Next, as shown in FIG. 2 (d), the electrode forming paste is selectively applied to a part of the light receiving surface (front surface) and the back surface, and then heat-treated to form the surface electrode 7 on the light receiving surface (front surface). A back electrode 5 is formed on the back surface. By using a paste containing a glass powder having fire-through property as an electrode forming paste applied to the light receiving surface side, the n ⁺ type diffusion layer 2 penetrates the antireflection film 3 as shown in FIG. A surface electrode 7 is formed on the surface to obtain an ohmic contact.
Further, since the p ⁺ -type diffusion layer 4 is already formed in the region where the back electrode is formed, the electrode forming paste for forming the back electrode 5 is not limited to the aluminum electrode paste, but may be a silver electrode paste or the like. An electrode paste capable of forming a lower resistance electrode can also be used. As a result, the power generation efficiency can be further increased.

  Finally, as shown in FIG. 2E, a composition for forming a semiconductor passivation film is formed on the p-type layer on the back surface other than the region where the back electrode 5 is formed to form a composition layer. The application can be performed by a coating method such as screen printing. The composition layer formed on the p-type layer is baked to form the semiconductor substrate passivation film 6. By forming the semiconductor substrate passivation film 6 formed from the composition for forming a semiconductor substrate passivation film on the p-type layer on the back surface, a solar cell element having excellent power generation efficiency can be manufactured.

2E shows a method of forming the semiconductor substrate passivation film only on the back surface portion, but in addition to the back surface side of the p-type semiconductor substrate 1, the semiconductor substrate passivation film forming material is applied to the side surface and dried. As a result, a semiconductor substrate passivation film may be further formed on the side surface (edge) of the p-type semiconductor substrate 1 (not shown). Thereby, the solar cell element which was further excellent in power generation efficiency can be manufactured.
Furthermore, the semiconductor substrate passivation film may be formed by applying the composition for forming a semiconductor substrate passivation film of the present invention only to the side surface without baking the semiconductor substrate passivation film on the back surface portion and baking this. When the composition for forming a semiconductor substrate passivation film of the present invention is used in a place where there are many crystal defects such as side surfaces, the effect is particularly great.

  In FIG. 2, the embodiment in which the passivation film is formed after forming the electrode has been described. However, after the passivation film is formed, an electrode such as aluminum may be formed in a desired region by vapor deposition or the like.

In the embodiment described above, the case where a p-type semiconductor substrate having an n ⁺ -type diffusion layer formed on the light-receiving surface has been described. However, an n-type semiconductor substrate having a p ⁺ -type diffusion layer formed on the light-receiving surface is described. Similarly, when used, a solar cell element can be produced. In this case, an n ⁺ type diffusion layer is formed on the back side.

Furthermore, the composition for forming a semiconductor substrate passivation film forms a semiconductor substrate passivation film 6 on the light receiving surface side or the back surface side of the back electrode type solar cell element in which electrodes are arranged only on the back surface side as shown in FIG. Can also be used.
As shown in a schematic cross-sectional view in FIG. 3, an n ⁺ -type diffusion layer 2 is formed in the vicinity of the surface on the light receiving surface side of the p-type semiconductor substrate 1, and the semiconductor substrate passivation film 6 and the antireflection film 3 are formed on the surface. Is formed. As the antireflection film 3, a silicon nitride film, a titanium oxide film, or the like is known. The semiconductor substrate passivation film 6 is formed by applying the composition for forming a semiconductor substrate passivation film of the present invention and baking it.

On the back surface side of the p-type semiconductor substrate 1, a back electrode 5 is provided on each of the p ⁺ -type diffusion layer 4 and the n ⁺ -type diffusion layer 2, and a semiconductor substrate passivation film is formed in a region where no back-side electrode is formed. 6 is provided.
The p ⁺ -type diffusion layer 4 can be formed by applying a heat treatment after applying the p-type diffusion layer forming composition or the aluminum electrode paste to a desired region as described above. Further, the n ⁺ -type diffusion layer 2 can be formed, for example, by applying a composition for forming an n-type diffusion layer capable of forming an n ⁺ -type diffusion layer by thermal diffusion treatment to a desired region and then performing a heat treatment.
Examples of the composition for forming an n-type diffusion layer include a composition containing a donor element-containing material and a glass component.

The back electrode 5 provided on each of the p ⁺ type diffusion layer 4 and the n ⁺ type diffusion layer 2 can be formed using a commonly used electrode forming paste such as a silver electrode paste. The back electrode 5 provided on the p ⁺ -type diffusion layer 4 may be an aluminum electrode formed with the p ⁺ -type diffusion layer 4 using aluminum electrode paste.

  The semiconductor substrate passivation film 6 provided on the back surface can be formed by applying a composition for forming a semiconductor passivation film to a region where the back electrode 5 is not provided and baking the composition. The semiconductor substrate passivation film 6 may be formed not only on the back surface of the semiconductor substrate 1 but also on the side surfaces (not shown).

  In the back electrode type solar cell element as shown in FIG. 3, since there is no electrode on the light receiving surface side, the power generation efficiency is excellent. Further, since the semiconductor substrate passivation film is formed in the region where the back electrode is not formed, the conversion efficiency is further improved.

  Although the example which used the p-type semiconductor substrate as the semiconductor substrate was shown above, also when an n-type semiconductor substrate is used, the solar cell element which is excellent in conversion efficiency according to the above can be manufactured.

<Solar cell>
The solar cell includes at least one of the solar cell elements, and is configured by arranging a wiring material on the electrode of the solar cell element. If necessary, the solar cell may be constituted by connecting a plurality of solar cell elements via a wiring material and further sealing with a sealing material.
The wiring material and the sealing material are not particularly limited, and can be appropriately selected from those usually used in the industry.
There is no restriction | limiting in the magnitude | size of the said solar cell. It is preferably 0.5m ² ~3m ^2.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “%” is based on mass.

<Example 1>
(Preparation of composition 1 for forming a semiconductor substrate passivation film)
40.3 g of ethyl acetoacetate aluminum diisopropylate (trade name: ALCH, manufactured by Kawaken Fine Chemical Co., Ltd.), 256.7 g of isobornylcyclohexanol (manufactured by Nippon Terpene Chemical Co., Ltd., trade name: Tersolve MTPH), terpineol (Japan) Terpen Chemical Co., Ltd.) was mixed to prepare a base composition. The content of the organoaluminum compound in the base composition is 12.6% by mass, the content of isobornylcyclohexanol is 79.9% by mass, and the content of terpineol is 7.5% by mass. 15.53 g of this base composition and 0.153 g of active energy ray-curable fluorosurfactant Megafac RS-72-K (manufactured by DIC) were mixed to prepare a composition 1 for forming a semiconductor substrate passivation film.

(Formation of passivation film)
As the semiconductor substrate, a single crystal p-type silicon substrate (manufactured by SUMCO, 50 mm square, thickness: 625 μm) having a mirror-shaped surface was used. The silicon substrate was pre-treated by immersing and cleaning at 70 ° C. for 5 minutes using an RCA cleaning solution (Frontier Cleaner-A01 manufactured by Kanto Chemical).

(Evaluation of uneven printing)
Thereafter, the composition 1 for forming a semiconductor substrate passivation film obtained as described above was applied on the entire surface of the silicon substrate using a screen printing method. At this time, printing was continuously performed on 10 silicon substrates, and it was visually confirmed that no printing unevenness occurred on all 10 of them. The results are shown in Table 1. The uneven printing refers to a phenomenon in which the above is extremely thinner than the surroundings because the wetness with the semiconductor substrate is insufficient when the screen plate is separated from the silicon substrate.
Of the printability items in Table 1, 9 or more out of 10 sheets that were not printed unevenly during printing were A, 8 or less and 6 or more B were 5 sheets. The following is written as C.

(Evaluation of storage stability)
The shear viscosity of the semiconductor substrate passivation film-forming composition 1 prepared above was measured immediately after preparation (within 12 hours) and after storage at 25 ° C. for 30 days, respectively. The shear viscosity was measured by attaching a cone plate (diameter 50 mm, cone angle 1 °) to MCR301 manufactured by Anton Paar, at a temperature of 25 ° C., and at a shear rate of 1.0 s ⁻¹ .
The rate of change in shear viscosity after storage at 25 ° C. for 30 days was calculated by 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)
η ₀ : Shear viscosity immediately after preparation (within 12 hours) η ₃₀ : Shear viscosity after storage at 5 ° C. for 30 days

[Evaluation criteria]
A: Change rate of shear viscosity was less than 10%.
B: Change rate of shear viscosity was 10% or more and less than 20%.
C: Change rate of shear viscosity was 20% or more.
If evaluation is A and B, it is favorable as a composition for forming a semiconductor substrate passivation film.

(Evaluation of coating film uniformity)
Moreover, it was visually confirmed similarly that the coated film after printing was 9 out of 10 sheets. The results are shown in Table 1. The state where the coating film is uniform indicates that the composition for forming a semiconductor substrate passivation film is present on the entire printed portion on the silicon substrate.
In addition, in the item of the coating film uniformity in Table 1, those in which the coating film was uniform visually after printing were 9 sheets out of 10 sheets A, 8 sheets or less and 6 sheets or more B The number of 5 or less is written as C.

After printing, the silicon substrate provided with the composition 1 for forming a semiconductor substrate passivation film was dried at 150 ° C. for 5 minutes. Next, the substrate was baked at 700 ° C. for 10 minutes and then allowed to cool at room temperature to prepare an evaluation substrate.
The thickness of the obtained passivation film was 1.54 μm. The thickness of the passivation film was calculated as an arithmetic average value by measuring the thickness at three points using a stylus type step / surface shape measuring device (Ambios).

(Measurement of effective lifetime)
The effective lifetime (μs) of the evaluation substrate obtained above was measured at room temperature by the reflected microwave photoelectric attenuation method using a lifetime measurement device (WT-2000PVN manufactured by Nippon Semi-Lab). The effective lifetime of the region to which the composition for forming a semiconductor substrate passivation film of the obtained evaluation substrate was applied was 310 μs.

<Example 2>
14.55 g of the above base composition and 0.155 g of the active energy ray-curable fluorine-based surfactant Megafac RS-75 (manufactured by DIC) were mixed to prepare a composition 2 for forming a semiconductor substrate passivation film.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 2 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Example 3>
The base composition 15.021 g and the active energy ray curable fluorosurfactant MegaFac RS-76-E (manufactured by DIC) (0.147 g) were mixed to prepare a semiconductor substrate passivation film forming composition 3.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 3 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Example 4>
The base composition 15.223 g and the modified silicone oil KBM 3063 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.160 g were mixed to prepare a semiconductor substrate passivation film forming composition 4.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 4 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Example 5>
The base composition 14.4849 g and the silane coupling agent KBM403 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.164 g were mixed to prepare a semiconductor substrate passivation film forming composition 5.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 5 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Example 6>
14.61 g of the above base composition and 0.161 g of silane coupling agent KBM503 (manufactured by Shin-Etsu Chemical) were mixed to prepare composition 6 for forming a semiconductor substrate passivation film.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 6 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Example 7>
The base composition 14.763 g and 0.076 g of the active energy ray-curable fluorine-based surfactant Megafac RS-72-K (manufactured by DIC) were mixed to prepare a composition 7 for forming a semiconductor substrate passivation film.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 7 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Example 8>
14.29 g of the above base composition and 0.729 g of the active energy ray-curable fluorine-based surfactant Megafac RS-72-K (manufactured by DIC) were mixed to prepare a composition 8 for forming a semiconductor substrate passivation film.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 8 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Example 9>
14.428 g of the above base composition and 1.428 g of the active energy ray-curable fluorosurfactant Megafac RS-72-K (manufactured by DIC) were mixed to prepare a composition 9 for forming a semiconductor substrate passivation film.
A passivation film was formed and evaluated in the same manner as in Example 1 except that the composition 9 for forming a semiconductor substrate passivation film was used. The results are shown in Table 1.

<Comparative Example 1>
As the semiconductor substrate, a single crystal p-type silicon substrate (manufactured by SUMCO, 50 mm square, thickness: 625 μm) having a mirror-shaped surface was used. The silicon substrate was pre-treated by immersing and cleaning at 70 ° C. for 5 minutes using an RCA cleaning solution (Frontier Cleaner-A01 manufactured by Kanto Chemical).
Then, it applied to the whole surface using the screen printing method on the silicon substrate which pre-processed the said base composition, and it dried at 150 degreeC for 5 minutes. Next, the substrate was baked at 700 ° C. for 10 minutes and then allowed to cool at room temperature to prepare an evaluation substrate.
Evaluation was performed in the same manner as in Example 1 except that the base composition was used. The results are shown in Table 1.

<Comparative example 2>
As the semiconductor substrate, a single crystal p-type silicon substrate (manufactured by SUMCO, 50 mm square, thickness: 625 μm) having a mirror-shaped surface was used. The silicon substrate was pre-treated by immersing and cleaning at 70 ° C. for 5 minutes using an RCA cleaning solution (Frontier Cleaner-A01 manufactured by Kanto Chemical).
Thereafter, the base composition was applied onto the entire surface of the silicon substrate pretreated by screen printing, and dried at 210 ° C. for 5 minutes. Next, the substrate was baked at 700 ° C. for 10 minutes and then allowed to cool at room temperature to prepare an evaluation substrate.
Evaluation was performed in the same manner as in Example 1 except that the base composition was used and the drying temperature was 210 ° C. The results are shown in Table 1.

  From the above, it can be seen that a semiconductor substrate passivation film having an excellent passivation effect can be formed by using the composition for forming a semiconductor substrate passivation film of the present invention. Moreover, it turns out that the composition for semiconductor substrate passivation film formation of this invention is excellent in storage stability. Furthermore, it can be seen that by using the composition for forming a semiconductor substrate passivation film of the present invention, the semiconductor substrate passivation film can be formed into a desired shape by a simple process.

DESCRIPTION OF SYMBOLS 1 p-type semiconductor substrate 2 n ⁺ type diffused layer 3 Antireflection film 4 p ⁺ type diffused layer 5 Back surface electrode 6 Passivation film 7 Surface electrode 8 Heat-treated product of p ⁺ type diffused layer formation composition or aluminum electrode

Claims (12)

A composition for forming a semiconductor substrate passivation film, comprising an organoaluminum compound represented by the following general formula (I) and at least one selected from a fluorine-based surfactant and a silicone-based surfactant.


[In the formula, R ¹ each independently represents an alkyl group having 1 to 8 carbon atoms. n represents an integer of 0 to 3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ] 2. The composition for forming a semiconductor substrate passivation film according to claim 1, wherein, in the general formula (I), each R ¹ is independently an alkyl group having 1 to 4 carbon atoms. In the said general formula (I), n is an integer of 1-3, R < ⁴ > is respectively independently a hydrogen atom or a C1-C4 alkyl group, The semiconductor substrate of Claim 1 or Claim 2 A composition for forming a passivation film.   The fluorosurfactant is contained, and the fluorosurfactant is at least one selected from an oligomer type fluorosurfactant and an active energy ray curable fluorosurfactant. The composition for forming a semiconductor substrate passivation film according to any one of items 3.   The silicone surfactant is contained, and the silicone surfactant is at least one selected from a side chain type silicone oil, a one-end type silicone oil, and a both-end type silicone oil. 5. The composition for forming a semiconductor substrate passivation film according to any one of 4 above.   The composition for forming a semiconductor substrate passivation film according to any one of claims 1 to 5, comprising the silicone-based surfactant, wherein the silicone-based surfactant is a silane coupling agent.   The composition for forming a semiconductor substrate passivation film according to any one of claims 1 to 6, further comprising a resin. Furthermore, the composition for semiconductor substrate passivation film formation of any one of Claims 1-7 containing the compound represented with the following general formula (II).

  The total content of the fluorine-based surfactant and the silicone-based surfactant is 0.01% by mass to 10% by mass, for forming a semiconductor substrate passivation film according to any one of claims 1 to 8. Composition.   A passivation film comprising: a semiconductor substrate; and a fired product layer of the composition for forming a semiconductor substrate passivation film according to claim 1, which is provided on the entire surface or a part of the semiconductor substrate. Attached semiconductor substrate. A step of applying a composition for forming a semiconductor substrate passivation film according to any one of claims 1 to 9 over the entire surface or part of the semiconductor substrate to form a composition layer;
Baking the composition layer to form a passivation film;
A method for manufacturing a semiconductor substrate with a passivation film, comprising: a semiconductor substrate in which a p-type layer and an n-type layer are pn-junction;
The fired product layer of the composition for forming a semiconductor substrate passivation film according to any one of claims 1 to 9, provided on the entire surface or a part of the semiconductor substrate,
An electrode disposed on the p-type layer or n-type layer of the semiconductor substrate;
A solar cell element having