JP2016134557A - Composition for forming passivation layer, semiconductor substrate with passivation layer using the same and method for manufacturing the same, solar battery element and method for manufacturing the same, and solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition having a good pattern formation and capable of forming a passivation layer with a good passivation effect in a simple manner, a semiconductor substrate with the passivation layer using the same and a method for manufacturing the same, a solar battery element and a method for manufacturing the same, and a solar battery.SOLUTION: A composition 5 for forming a passivation layer contains a compound represented by a general formula (I) and an organic compound represented by a general formula (II), and a content of the general formula (II) is 30 to 90 mass%, based on 100 mass% of the composition for forming the passivation layer. In the general formula(I), M represents at least one selected from the group consisting of Al, Nb, Ta, V, Y and Hf. R1 independently represents alkyl group or aryl group. The m represents an integer of 1-5.SELECTED DRAWING: Figure 1

Description

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

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 achieve high efficiency, and then 800 to 900 ° C. in a mixed gas atmosphere of phosphorus oxychloride (POCl ₃ ), nitrogen and oxygen. The n-type diffusion layer is uniformly formed by performing several tens of minutes. 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 formed on the side surface. Further, the n-type diffusion layer formed on the back surface needs to be converted into a p ⁺ -type diffusion layer. For this reason, by applying an aluminum paste containing aluminum powder and a binder to the entire back surface and heat-treating (baking) it, the n-type diffusion layer is converted into a p ⁺ -type diffusion layer and an aluminum electrode is formed. Get ohmic contact.

  However, an aluminum electrode formed from an aluminum paste has low conductivity, and in order to reduce sheet resistance, an aluminum electrode generally formed on the entire back surface must have a thickness of about 10 to 20 μm after heat treatment (firing). Don't be. Furthermore, since the thermal expansion coefficient differs greatly between silicon and aluminum, a large internal stress is generated in the silicon substrate during the heat treatment (firing) and cooling in the silicon substrate on which the aluminum electrode is formed, and the grain boundary Cause damage, crystal defect growth, and warping.

In order to solve this problem, there is a method of reducing the coating amount of the aluminum paste and reducing the thickness of the back 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, a point contact technique has been proposed in which an aluminum paste is applied to a part of the surface of a silicon substrate to partially form a p ⁺ -type diffusion layer and an aluminum electrode (for example, see Patent Document 1). ).
In the case of a solar cell having a point contact structure on the surface opposite to the light receiving surface (hereinafter also referred to as “back surface”), it is necessary to suppress the recombination rate of minority carriers on the surface of the portion other than the aluminum electrode. is there. For this purpose, a SiO ₂ film or the like has been proposed as a passivation layer for the back surface (see, for example, Patent Document 2). As a passivation effect by forming such a SiO ₂ film, there is an effect of terminating the dangling bonds of silicon atoms in the back surface layer portion of the silicon substrate and reducing the surface state density causing recombination.

As another method of 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 layer. Such a passivation effect is generally called a field effect, and an aluminum oxide (Al ₂ O ₃ ) film or the like has been proposed as a material having a negative fixed charge (see, for example, Patent Document 3).
Such a passivation layer is generally formed by a method such as an ALD (Atomic Layer Deposition) method or a CVD (Chemical Vapor Deposition) method (for example, see Non-Patent Document 1). 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 and 3).

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

Journal of Applied Physics, 104 (2008), 113703-1 to 113703-7. Thin Solid Films, 517 (2009), 6327-6330 Chinese Physics Letters, 26 (2009), 088102-1 to 088102-4

  Since the method described in Non-Patent Document 1 includes complicated manufacturing processes such as vapor deposition, it may be difficult to improve productivity. Moreover, in the composition for forming a passivation layer used in the methods described in Non-Patent Documents 2 and 3, since the spin coating method is included in the manufacturing process, it may be difficult to form a film in a target pattern in a short process. .

  The present invention has been made in view of the above-described conventional problems, and provides a composition for forming a passivation layer capable of forming a passivation layer having an excellent pattern forming property and an excellent passivation effect by a simple method. The task is to do. In addition, the present invention provides a semiconductor substrate with a passivation layer, which is obtained using the composition for forming a passivation layer of the present invention and has a passivation layer having an excellent passivation effect, a manufacturing method thereof, and a solar cell having excellent conversion efficiency. It is an object to provide an element, a manufacturing method thereof, and a solar cell.

Specific means for achieving the above object are as follows.
<1> A composition for forming a passivation layer, comprising a compound represented by the following general formula (I) and an organic compound represented by the following general formula (II), wherein the content of the general formula (II) is The composition for formation of a passivation layer which is 30-90 mass% with respect to 100 mass%.

［一般式（Ｉ）中、Ｍは、Ａｌ、Ｎｂ、Ｔａ、Ｖ、Ｙ及びＨｆからなる群より選択される少なくとも１種を表す。Ｒ^１はそれぞれ独立してアルキル基又はアリール基を表す。ｍは１〜５の整数を表す。］

[In General Formula (I), M represents at least one selected from the group consisting of Al, Nb, Ta, V, Y, and Hf. R ¹ independently represents an alkyl group or an aryl group. m represents an integer of 1 to 5. ]

<2> The composition for forming a passivation layer according to <1>, further comprising a compound represented by the following general formula (III).

［一般式（ＩＩＩ）中、Ｒ^２はそれぞれ独立してアルキル基を表す。ｎは１〜３の整数を表す。Ｘ^２及びＸ^３はそれぞれ独立して酸素原子又はメチレン基を表す。Ｒ^３、Ｒ^４及びＲ^５はそれぞれ独立して水素原子又はアルキル基を表す。］

[In General Formula (III), each R ² independently represents an alkyl group. n represents an integer of 1 to 3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ³ , R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group. ]

<3> a semiconductor substrate and a passivation layer that is a heat treatment product of the composition for forming a passivation layer according to <1> or <2>, provided on at least a part of at least one surface of the semiconductor substrate. A semiconductor substrate with a passivation layer.

<4> forming a composition layer by applying the passivation layer forming composition according to <1> or <2> to at least a part of at least one surface of the semiconductor substrate; and A method of manufacturing a semiconductor substrate with a passivation layer, comprising: a step of forming a passivation layer by heat treatment.

<5> The semiconductor substrate according to <1> or <2>, which is provided on at least a part of at least one surface of the semiconductor substrate having a pn junction part in which a p-type layer and an n-type layer are pn-junctioned. A solar cell element comprising: a passivation layer that is a heat treatment product of the passivation layer forming composition; and an electrode disposed on at least one of the p-type layer and the n-type layer.

<6> The composition for forming a passivation layer according to <1> or <2>, wherein at least part of at least one surface of a semiconductor substrate having a pn junction formed by pn junction of a p-type layer and an n-type layer. An electrode is disposed on at least one of the p-type layer and the n-type layer, and a step of forming a passivation layer by heat-treating the composition layer. And a method for producing a solar cell element.

<7> A solar cell comprising the solar cell element according to <5> and a wiring material disposed on the electrode of the solar cell element.

  ADVANTAGE OF THE INVENTION According to this invention, the composition for passivation layer formation which can form the passivation layer excellent in the pattern formation property and excellent in the passivation effect by a simple method can be provided. Further, according to the present invention, a semiconductor substrate with a passivation layer, which is obtained using the composition for forming a passivation layer of the present invention and has a passivation layer having an excellent passivation effect, a manufacturing method thereof, and a solar having excellent conversion efficiency A battery element, a manufacturing method thereof, and a solar battery can be provided.

It is sectional drawing which shows typically an example of the manufacturing method of the solar cell element which has a passivation layer which concerns on this embodiment. It is sectional drawing which shows typically another example of the manufacturing method of the solar cell element which has a passivation layer which concerns on this embodiment. It is sectional drawing which shows typically another example of the manufacturing method of the solar cell element which has a passivation layer which concerns on this embodiment. It is a schematic plan view which shows an example of the light-receiving surface of the solar cell element of this embodiment. It is a schematic plan view which shows an example of the formation pattern in the back surface of the passivation layer which concerns on this embodiment. It is a schematic plan view which shows another example of the formation pattern in the back surface of the passivation layer which concerns on this embodiment. It is the schematic plan view to which the A section of FIG. 5 was expanded. It is the schematic plan view to which the B section of FIG. 5 was expanded. It is a schematic plan view which shows an example of the back surface of the solar cell element of this embodiment. It is a figure for demonstrating an example of the manufacturing method of the solar cell of this embodiment.

  In this specification, the term “process” is not limited to an independent process, and is included in this term if the purpose of the process is achieved even when it cannot be clearly distinguished from other processes. Moreover, the numerical range shown using "to" shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively. Furthermore, the content of each component in the composition means 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. In addition, in the present specification, the term “layer” includes a configuration of a shape formed in part in addition to a configuration of a shape formed on the entire surface when observed as a plan view.

<Composition for forming a passivation layer>
The first composition for forming a passivation layer of the present invention is represented by a compound represented by the following general formula (I) (hereinafter also referred to as “compound of formula (I)”) and the following general formula (II). Organic compounds (hereinafter also referred to as “compounds of formula (II)”).
The composition for forming a passivation layer of the present invention may further contain other components as necessary. When the composition for forming a passivation layer of the present invention contains the above components, it is possible to form a passivation layer having excellent pattern forming properties and excellent passivation effect by a simple technique.

In general formula (I), M represents at least one selected from the group consisting of Al, Nb, Ta, V, Y, and Hf. R ¹ independently represents an alkyl group or an aryl group. m represents an integer of 1 to 5.

  A composition for forming a passivation layer containing a compound of formula (I) and a compound of formula (II) is applied to a semiconductor substrate to form a composition layer of a desired shape, and this is heat-treated (fired). A passivation layer having a passivation effect can be formed in a desired shape. The method using the composition for forming a passivation layer 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 layer can be formed in a desired shape without requiring a complicated process such as mask processing. In addition, since the composition for forming a passivation layer contains the compound of formula (I), occurrence of problems such as gelation is suppressed, and the storage stability with time is excellent. Since the composition for forming a passivation layer of the present invention contains an organic compound represented by the general formula (II), a composition layer having a desired shape can be formed, while represented by the general formula (II). Since the organic compound can be eliminated by vaporization by heating, the generation of black residue is suppressed.

  In this specification, the passivation effect of a semiconductor substrate is obtained by reflecting the effective lifetime of minority carriers in a semiconductor substrate on which a passivation layer is formed, using a 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 between the passivation layer and the semiconductor substrate and the internal characteristics of the semiconductor substrate such as dangling bonds can be evaluated.

  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.

(Compound represented by formula (I))
The composition for forming a passivation layer contains at least one compound represented by the general formula (I) (compound of formula (I)). When the composition for forming a passivation layer contains at least one compound of formula (I), a passivation layer having an excellent passivation effect can be formed. The reason for this can be considered as follows.

  The metal oxide formed by heat-treating (firing) the passivation layer-forming composition containing the compound of formula (I) is considered to have defects of metal atoms or oxygen atoms and easily generate fixed charges. When this fixed charge generates charge near the interface of the semiconductor substrate, the concentration of minority carriers can be reduced. As a result, the carrier recombination rate at the interface is suppressed, and an excellent passivation effect is achieved. Conceivable.

  Here, as for the state of the passivation layer that generates a fixed charge on the semiconductor substrate, the cross section of the semiconductor substrate is subjected to electron transmission loss electron spectroscopy (EELS, Electron Energy Loss Spectroscopy) using a Scanning Transmission Electron Microscope (STEM, Scanning Transmission Electron Microscope). It can be evaluated by examining the binding mode in the analysis of). In addition, by measuring an X-ray diffraction spectrum (XRD, X-ray diffraction), the crystal phase near the interface of the passivation layer can be confirmed. Furthermore, the fixed charge of the passivation layer can be evaluated by a CV method (Capacitance Voltage measurement).

  In the general formula (I), M is at least one selected from the group consisting of Al, Nb, Ta, V, Y, and Hf. The passivation effect, the pattern forming property of the composition for forming a passivation layer, and the passivation From the viewpoint of workability in preparing the layer forming composition, M is preferably at least one selected from the group consisting of Al, Nb, Ta and Y.

In the general formula (I), each R ¹ independently represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 14 carbon atoms, and an alkyl group having 1 to 8 carbon atoms. Are more preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable. The alkyl group represented by R ¹ may be linear or branched.
Examples of the alkyl group represented by R ¹ include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, hexyl group, An octyl group, an ethylhexyl group, etc. can be mentioned.
Specific examples of the aryl group represented by R ¹ include a phenyl group.
The alkyl group and aryl group represented by R ¹ may have a substituent, and examples of the substituent include methyl group, ethyl group, i-propyl group, amino group, hydroxy group, carboxy group, sulfo group. Group, nitro group and the like.
Among these, R ¹ is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, and more preferably an unsubstituted alkyl group having 1 to 4 carbon atoms, from the viewpoint of reactivity with water and a passivation effect. preferable.

  In general formula (I), m represents an integer of 1 to 5. Here, from the viewpoint of reactivity with water, m is preferably 3 when M is Al, m is preferably 5 when M is Nb, and M is Ta. In some cases, m is preferably 5, m is preferably V when m is V, m is preferably 3 when M is Y, and M is Hf. In this case, m is preferably 4.

As the compound of formula (I), M is at least one selected from the group consisting of Al, Nb, Ta and Y, R ¹ is an unsubstituted alkyl group having 1 to 4 carbon atoms, and m is It is preferably an integer of 1 to 5, more preferably M is Nb, R ¹ is an unsubstituted alkyl group having 1 to 4 carbon atoms, and m is 5.

  The state of the compound represented by the general formula (I) may be solid or liquid. From the viewpoint of the storage stability of the composition for forming a passivation layer and the miscibility in the case where a compound represented by the general formula (III) described later is used in combination, the compound represented by the general formula (I) may be a liquid. preferable.

  The compound of formula (I) is aluminum methoxide, aluminum ethoxide, aluminum-i-propoxide, aluminum-n-propoxide, aluminum-n-butoxide, aluminum-t-butoxide, aluminum-i-butoxide, niobium methoxide. , Niobium ethoxide, niobium-i-propoxide, niobium-n-propoxide, niobium-n-butoxide, niobium-t-butoxide, niobium-i-butoxide, tantalum methoxide, tantalum ethoxide, tantalum-i-propoxy Tantalum-n-propoxide, tantalum-n-butoxide, tantalum-t-butoxide, tantalum-i-butoxide, yttrium methoxide, yttrium ethoxide, yttrium-i-propoxide, yttrium-n-propoxide, Yttrium-n-butoxide, yttrium-t-butoxide, yttrium-i-butoxide, vanadium oxymethoxide, vanadium oxyethoxide, vanadium oxy-i-propoxide, vanadium oxy-n-propoxide, vanadium oxy-n-butoxide , Vanadium oxy-t-butoxide, vanadium oxy-i-butoxide, hafnium methoxide, hafnium ethoxide, hafnium-i-propoxide, hafnium-n-propoxide, hafnium-n-butoxide, hafnium-t-butoxide, hafnium -I-butoxide and the like, among which aluminum ethoxide, aluminum-i-propoxide, aluminum-n-butoxide, niobium ethoxide, niobium-n-propoxide, niobium Bed -n- butoxide, tantalum ethoxide, tantalum -n- propoxide, tantalum -n- butoxide, yttrium -i- propoxide, and yttrium -n- butoxide are preferred.

  In addition, the compound of formula (I) may be a prepared product or a commercially available product. Commercially available products include, for example, pentamethoxyniobium, pentaethoxyniobium, penta-i-propoxyniobium, penta-n-propoxyniobium, penta-i-butoxyniobium, penta-n-butoxyniobium from High Purity Chemical Laboratory Co. , Penta-sec-butoxy niobium, pentamethoxy tantalum, pentaethoxy tantalum, penta-i-propoxy tantalum, penta-n-propoxy tantalum, penta-i-butoxy tantalum, penta-n-butoxy tantalum, penta-sec-butoxy tantalum , Penta-t-butoxytantalum, vanadium (V) trimethoxide oxide, vanadium (V) triethoxy oxide, vanadium (V) tri-i-propoxide oxide, vanadium (V) tri-n-propoxide oxide, vanadium (V Tri-i-butoxide oxide, vanadium (V) tri-n-butoxide oxide, vanadium (V) tri-sec-butoxide oxide, vanadium (V) tri-t-butoxide oxide, tri-i-propoxy yttrium, tri-n -Butoxy yttrium, tetramethoxy hafnium, tetraethoxy hafnium, tetra-i-propoxy hafnium, tetra-t-butoxy hafnium, pentaethoxyniobium, pentaethoxy tantalum, pentaboxy tantalum, yttrium-n-butoxide from Hokuko Chemical Co., Ltd. Hafnium-tert-butoxide, vanadium oxytriethoxide, vanadium oxytrinormal propoxide, vanadium oxytrinormal butoxide, vanadium oxy from Nichia Corporation Riisobutokishido, it can be mentioned vanadium oxy-tri secondary butoxide and the like.

  The compound of formula (I) is prepared by reacting a specific metal (M) halide with an alcohol in the presence of an inert organic solvent, and further adding ammonia or amines to extract the halogen (specialty). Known manufacturing methods such as Japanese Utility Model Laid-Open No. 63-227593 and Japanese Patent Laid-Open No. 3-291247) can be used.

  A part of the compound of formula (I) may be contained in the composition for forming a passivation layer of the present invention as a compound in which a chelate structure is formed by mixing with a compound having a specific structure having two carbonyl groups described later. .

  The presence of the chelate structure in the compound represented by the general formula (I) 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 rate of the compound of Formula (I) contained in the said composition for formation of a passivation layer can be suitably selected as needed. The content rate of a compound of a formula (I) can be 0.1-80 mass% in the composition for passivation layer formation from a viewpoint of storage stability and a passivation effect, and is 0.5-70 mass%. It is preferably 1 to 60% by mass, more preferably 1 to 50% by mass.

(Organic compound represented by general formula (II))
The composition for forming a passivation layer contains an organic compound (compound of formula (II)) represented by general formula (II).

  The composition for forming a passivation layer can improve the passivation effect by containing the organic compound represented by the general formula (II), and can suppress a black residue after heat treatment (firing). . As an organic compound represented by general formula (II), isobornyl cyclohexanol is mentioned, for example.

  As isobornyl cyclohexanol, “Telsolve MTPH” (Nippon Terpene Chemical Co., Ltd., trade name) is commercially available. Isobornyl cyclohexanol has a high boiling point of 308 to 318 ° C, and when it is removed from the composition layer, it does not need to be degreased by heat treatment (firing) like a resin, but disappears by vaporizing by heating. Can be made. For this reason, most of the solvent and isobornylcyclohexanol contained in the passivation layer forming composition can be removed as necessary in the drying step after coating on the semiconductor substrate, and after heat treatment (baking) The black residue can be suppressed.

It is thought that the passivation effect becomes higher by combining the compound represented by the general formula (I) and the organic compound represented by the general formula (II). This can be thought of as follows.
When the composition for forming a passivation layer containing a binder resin is used, voids are generated in the passivation layer due to the removal of the binder resin by the degreasing treatment, and the passivation layer tends to be formed unevenly. On the other hand, the organic compound represented by the general formula (II) can be vaporized by heating and eliminated without performing a degreasing treatment. Therefore, in the passivation layer formed by using the composition for forming a passivation layer of the present invention in which the compound represented by the general formula (I) and the organic compound represented by the general formula (II) are combined, voids are generated. Thus, the uniformity of the passivation layer is also improved, and as a result, the passivation effect due to the electric field effect is considered to be sufficient.

  The content of the organic compound represented by the general formula (II) contained in the composition for forming a passivation layer is preferably 30 to 99.9% by mass, more preferably 40 to 95% by mass, More preferably, it is 60-90 mass%.

(Compound represented by formula (III))
The composition for forming a passivation layer of the present invention may contain at least one compound represented by the following general formula (III) (hereinafter referred to as “organoaluminum compound”).

In general formula (III), each R ² independently represents an alkyl group. n represents an integer of 1 to 3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ³ , R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group.

  The passivation effect can be further improved because the composition for forming a passivation layer of the present invention contains the organoaluminum compound. This can be considered as follows.

The 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. In addition, Journal of the Ceramic Society of Japan (Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi), vol. 97, pp 396-399 (1989), the organoaluminum compound becomes aluminum oxide (Al ₂ O ₃ ) by heat treatment (firing). At this time, since the formed aluminum oxide is likely to be in an amorphous state, a four-coordinate aluminum oxide layer is easily formed in the vicinity of the interface with the semiconductor substrate, and may have a large negative fixed charge due to the four-coordinate aluminum oxide. It is considered possible. At this time, it is considered that a passivation layer having an excellent passivation effect can be formed as a result of compounding with the compound derived from the formula (I) having a fixed charge or an oxide derived from the hydrolyzate thereof.

  In addition to the above, by combining the compound of formula (I) or a hydrolyzate thereof and an organoaluminum compound as in the present invention, it is considered that the passivation effect is further enhanced by the respective effects in the passivation layer. Further, the compound (I) or the hydrolyzate thereof and the organoaluminum compound are heat-treated (fired), whereby the metal (M) and aluminum (Al) contained in the compound (I) are mixed. It is considered that the reactivity as a composite metal alkoxide and physical properties such as vapor pressure are improved, the denseness of the passivation layer as a heat-treated product (baked product) is improved, and as a result, the passivation effect is further enhanced.

In general formula (III), R ² represents an alkyl group independently, preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by R ² may be linear or branched. Examples of the alkyl group represented by R ² include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, hexyl group, An octyl group, an ethylhexyl group, etc. can be mentioned. Among them, the alkyl group represented by R ² 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 (III), n represents an integer of 1 to 3. n is preferably 1 or 3 from the viewpoint of storage stability, and more preferably 1 from the viewpoint of solubility.
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 ³ , R ⁴ and R ⁵ in the general formula (III) each independently represent a hydrogen atom or an alkyl group. The alkyl group represented by R ³ , R ⁴ and R ⁵ may be linear or branched. The alkyl group represented by R ³ , R ⁴ and R ⁵ is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. As alkyl groups having 1 to 8 carbon atoms, methyl group, ethyl group, propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, hexyl group, octyl group, ethylhexyl Groups and the like.

Among these, from the viewpoint of storage stability and a passivation effect, R ³ and R ⁴ are preferably each independently a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms, More preferably, it is an unsubstituted alkyl group of 4.
R ⁵ 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.

From the viewpoint of storage stability, the organoaluminum compound is preferably a compound in which n is an integer of 1 to 3, and R ⁵ is independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

From the viewpoint of storage stability and passivation effect, the organoaluminum compound is an integer from 1 to 3, R ² is each independently an alkyl group having 1 to 4 carbon atoms, and at least X ² and X ³ One is an oxygen atom, R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁵ is a compound that is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. It is preferable. In the organoaluminum compound, n is an integer of 1 to 3, R ² is each independently an unsubstituted alkyl group having 1 to 4 carbon atoms, and at least one of X ² and X ³ is an oxygen atom, When R ³ or R ⁴ bonded to the oxygen atom is an alkyl group having 1 to ⁴ carbon atoms and X ² or X ³ is a methylene group, R ³ or R ⁴ bonded to the methylene group is a hydrogen atom. More preferably, R ⁵ is a hydrogen atom.

  Examples of the organoaluminum compound represented by the general formula (III), where n is an integer of 1 to 3, include aluminum ethyl acetoacetate di-i-propylate and tris (ethyl acetoacetate) aluminum.

  Moreover, as the organoaluminum compound represented by the general formula (III) and n being an integer 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-50F, ALCH-75, ALCH-TR, ALCH-TR-20, and the like.

The organoaluminum compound represented by the general formula (III) and n is an integer of 1 to 3 is prepared by mixing the aluminum trialkoxide and a compound having a specific structure having two carbonyl groups described later. be able to. A commercially available aluminum chelate compound may also be used.
When the aluminum trialkoxide is mixed with a compound having a specific structure having two carbonyl groups, 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 liquid medium may be present, and heat treatment, addition of a catalyst, and the like 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 passivation layer containing this is further improved. To do.

  The compound having a specific structure having two carbonyl groups may be 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 reactivity and storage stability. preferable. As the compound having a specific structure having the two carbonyl groups, acetylacetone, 3-methyl-2,4-pentanedione, 2,3-pentanedione, 3-ethyl-2,4-pentanedione, 3-butyl-2, Β- such as 4-pentanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 2,6-dimethyl-3,5-heptanedione, 6-methyl-2,4-heptanedione, etc. Diketone compound, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, acetoacetate-i-propyl, acetoacetate-i-butyl, acetoacetate-n-butyl, acetoacetate-t-butyl, acetoacetate-n -Pentyl, acetoacetate-i-pentyl, acetoacetate-n-hexyl, acetoacetate-n-octyl, acetoacetate-n-heptyl, acetoacetate 3-pen , Ethyl 2-acetylheptanoate, ethyl 2-methylacetoacetate, ethyl 2-butylacetoacetate, ethyl hexylacetoacetate, ethyl 4,4-dimethyl-3-oxovalerate, ethyl 4-methyl-3-oxovalerate, Ethyl 2-ethylacetoacetate, methyl 4-methyl-3-oxovalerate, ethyl 3-oxohexanoate, ethyl 3-oxovalerate, methyl 3-oxovalerate, methyl 3-oxohexanoate, 3-oxoheptanoic acid Β-ketoester compounds such as ethyl, methyl 3-oxoheptanoate, methyl 4,4-dimethyl-3-oxovalerate, dimethyl malonate, diethyl malonate, di-n-propyl malonate, di-i-malonate Propyl, di-n-butyl malonate, di-t-butyl malonate, dihexyl malonate, tert-butyl malonate Malonic acid such as diethyl methylmalonate, diethyl ethylmalonate, diethyl i-propylmalonate, diethyl n-butylmalonate, diethyl sec-butylmalonate, diethyl i-butylmalonate, diethyl 1-methylbutylmalonate A diester etc. can be mentioned.

  The number of aluminum chelate structures can be controlled, for example, by appropriately adjusting the ratio of mixing the aluminum trialkoxide and a compound having a specific structure having two carbonyl groups. Moreover, you may select suitably the compound which has a desired structure from a commercially available aluminum chelate compound.

  Among organoaluminum compounds, at least one selected from aluminum ethyl acetoacetate di-i-propylate and tri-i-propoxyaluminum, specifically from the viewpoint of the passivation effect and compatibility with the solvent contained as necessary It is preferable to use seeds, and it is more preferable to use aluminum ethyl acetoacetate di-i-propylate.

  The presence of the aluminum chelate structure in the 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 organoaluminum compound may be liquid or solid and is not particularly limited. From the viewpoint of the passivation effect and storage stability, the homogeneity of the formed passivation layer is further improved by using an organoaluminum compound having good stability at room temperature (25 ° C.) and solubility or dispersibility. A desired passivation effect can be stably obtained.

In the composition for forming a passivation layer of the present invention, when an organoaluminum compound is included, the content of the organoaluminum compound is not particularly limited. Among them, the content of the organoaluminum compound when the total content of the compound of formula (I) or a hydrolyzate thereof and the organoaluminum compound is 100% by mass is preferably 0.5 to 80% by mass, It is more preferably 1 to 75% by mass, still more preferably 2 to 70% by mass, and particularly preferably 3 to 70% by mass.
By setting the content of the organoaluminum compound to 0.5% by mass or more, the storage stability of the composition for forming a passivation layer tends to be improved. Moreover, it exists in the tendency for the passivation effect to improve by making an organoaluminum compound 80 mass% or less.

  When the composition for forming a passivation layer of the present invention contains an organoaluminum compound, the content of the organoaluminum compound in the composition for forming a passivation layer can be appropriately selected as necessary. The content of the organoaluminum compound can be 0.1 to 60% by mass in the composition for forming a passivation layer and 0.5 to 55% by mass from the viewpoint of storage stability and a passivation effect. Preferably, it is 1-50 mass%, More preferably, it is 1-45 mass%.

(Liquid medium)
The composition for forming a passivation layer of the present invention may contain a liquid medium (solvent or dispersion medium). When the composition for forming a passivation layer contains a liquid medium, the viscosity can be easily adjusted, the impartability can be further improved, and a more uniform passivation layer can be formed. The liquid medium is not particularly limited and can be appropriately selected as necessary. Among these, a liquid medium capable of dissolving the compound of formula (I) and the compound of formula (II) and the organoaluminum compound added as necessary to give a uniform solution is preferable, and includes at least one organic solvent. More preferred. A liquid medium means a medium in a liquid state at room temperature (25 ° C.).

  Liquid media 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, methyl-n-hexyl ketone, diethyl Ketone solvents such as ketone, di-n-propyl 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 di-n-butyl 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 Recall methyl-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 di-n-butyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, Dipropylene glycol methyl ethyl ether, dipro Pyrene glycol methyl-n-butyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene Glycol methyl ethyl ether, tripropylene glycol methyl-n-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl-n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetrapropylene glycol methyl ethyl ether Tetrapropylene glycol methyl-n-butyl ether, Ether solvents such as lapropylene glycol di-n-butyl ether, tetrapropylene glycol methyl-n-hexyl ether, tetrapropylene glycol di-n-butyl ether, methyl acetate, ethyl acetate, acetic acid-n-propyl, acetic acid-i-propyl, Acetic acid-n-butyl, acetic acid-i-butyl, acetic acid-sec-butyl, acetic acid-n-pentyl, acetic acid-sec-pentyl, acetic acid-3-methoxybutyl, acetic acid methylpentyl, acetic acid-2-ethylbutyl, acetic acid-2 -Ethylhexyl, 2- (2-butoxyethoxy) ethyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, Acid dipropylene glycol methyl ether, acetic acid dipropylene glycol ethyl ether, diacetic acid glycol, methoxytriethylene glycol acetate, acetic acid-i-amyl, ethyl propionate, propionic acid-n-butyl, propionic acid-i-amyl, oxalic acid Diethyl, di-n-butyl oxalate, methyl lactate, ethyl lactate, lactate-n-butyl, lactate-n-amyl, ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, Ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, γ-butyrolac , Ester solvents such as γ-valerolactone, acetonitrile, N-methylpyrrolidinone, N-ethylpyrrolidinone, Nn-propylpyrrolidinone, Nn-butylpyrrolidinone, Nn-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N , N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, and other aprotic polar solvents, methylene chloride, chloroform, dichloroethane, benzene, toluene, xylene, hexane, octane, ethylbenzene, 2-ethylhexanoic acid, etc. Organic 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-octanol , N-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, benzyl alcohol, ethylene glycol, 1,2 -Alcohol solvents such as propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, Tylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol mono- glycol monoether solvents such as n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, terpinene, terpineol, myrcene, alloocimene, limonene, dipentene, pinene, carvone, Oshmen, Fu Terpene solvents such Randoren like. These liquid media are used alone or in combination of two or more.

  Among these, the liquid medium 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 impartability to a semiconductor substrate and pattern formation, and is selected from the group consisting of a terpene solvent. More preferably, it contains at least one selected from the above.

  When the composition for forming a passivation layer includes a liquid medium, the content of the liquid medium is determined in consideration of the imparting property, the pattern forming property, and the storage stability. For example, the content of the liquid medium is preferably 5 to 98% by mass, and preferably 10 to 95% by mass in the total mass of the composition for forming a passivation layer, from the viewpoint of the impartability of the composition and the pattern forming property. More preferably.

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

The type of resin is not particularly limited. The resin is preferably a resin whose viscosity can be adjusted within a range where a good pattern can be formed when the composition for forming a passivation layer of the present invention is applied on a semiconductor substrate. Examples of resins include polyvinyl alcohol, polyacrylamide, polyacrylamide derivatives, polyvinylamide, polyvinylamide derivatives, polyvinylpyrrolidone, polyethylene oxide, polyethylene oxide derivatives, polysulfonic acid, polyacrylamide alkylsulfonic acid, cellulose, cellulose derivatives (carboxymethylcellulose, hydroxyethylcellulose) , Cellulose ethers such as ethyl cellulose), gelatin, gelatin derivatives, starch, starch derivatives, sodium alginate, sodium alginate derivatives, xanthan, xanthan derivatives, guar gum, guar gum derivatives, scleroglucan, scleroglucan derivatives, tragacanth, tragacanth derivatives, Dextrin, dextrin derivative, (meth) acrylic Resins, (meth) acrylic acid ester resin (alkyl (meth) acrylate resin, dimethylaminoethyl (meth) acrylate resin, etc.), butadiene resins, styrene resins, siloxane resins, copolymers thereof and the like. These resins are used singly or in combination of two or more.
In the present invention, (meth) acryl represents acryl or methacryl, and (meth) acrylate represents acrylate or methacrylate.

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.
Moreover, the molecular weight of these resins is not particularly limited, and it is preferable to adjust appropriately in view of a desired viscosity as a composition for forming a passivation layer. The weight average molecular weight of the resin is preferably 1000 to 10,000,000, and more preferably 1,000 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 the molecular weight distribution measured using GPC (gel permeation chromatography).

When the composition for forming a passivation layer of the present invention contains a resin, the content of the resin in the composition for forming a passivation layer can be appropriately selected as necessary. For example, the resin content is preferably 0.1 to 50% by mass in the total mass of the composition for forming a passivation layer. From the viewpoint of expressing thixotropy that facilitates pattern formation, the resin content is more preferably 0.2 to 25% by mass, still more preferably 0.5 to 20% by mass, It is especially preferable that it is 0.5-15 mass%.
In addition, since the composition for forming a passivation layer of the present invention is excellent in thixotropy, it is not necessary to develop thixotropy with a resin. Therefore, the content of the resin contained in the composition for forming a passivation layer of the present invention is preferably 0.5% by mass or less, more preferably 0.2% by mass or less, still more preferably 0.1% by mass or less, and substantially It is particularly preferable that no resin is contained.

(Other ingredients)
The composition for forming a passivation layer of the present invention may further contain other components that are usually used in the art as needed, in addition to the components described above.
The composition for forming a passivation layer of the present invention may contain an acidic compound or a basic compound. When the composition for forming a passivation layer contains an acidic compound or a basic compound, from the viewpoint of storage stability, the content of the acidic compound or the basic compound is 1% by mass or less in the composition for forming a passivation layer, respectively. It is preferable that the content is 0.1% by mass or less.
Examples of the acidic compound include Bronsted acid and Lewis acid, inorganic acids such as hydrochloric acid and nitric acid, and organic acids such as acetic acid. Examples of basic compounds include Bronsted bases and Lewis bases. Examples of basic compounds include inorganic bases such as alkali metal hydroxides and alkaline earth metal hydroxides, trialkylamines, and pyridines. An organic base etc. can be mentioned.

  Examples of other components include plasticizers, dispersants, surfactants, thixotropic agents, other metal alkoxide compounds, and high-boiling materials. Among these, it is preferable to include at least one selected from thixotropic agents. By including at least one selected from thixotropic agents, the shape stability of the composition layer formed by applying the composition for forming a passivation layer of the present invention on a semiconductor substrate is further improved, and the passivation layer is formed as described above. It can be formed in a desired shape in the region where the composition layer is formed.

  Examples of the thixotropic agent include fatty acid amides, polyalkylene glycol compounds, organic fillers, and inorganic fillers. Examples of the polyalkylene glycol compound include compounds represented by the following general formula (IV).

In general formula (IV), R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group, and R ⁸ represents an alkylene group. n is an arbitrary integer of 3 or more. Incidentally, R ⁸ in the presence of a plurality of (O-R ⁸⁾ may or may not be the same.

  Examples of the fatty acid amide include compounds represented by the following general formulas (1), (2), (3) and (4).

In general formulas (1), (2), (3) and (4), R ⁹ and R ¹¹ each independently represent an alkyl group or alkenyl group having 1 to 30 carbon atoms, and R ¹⁰ represents 1 to ¹⁰ carbon atoms. Represents an alkylene group. R ⁹ and R ¹¹ may be the same or different.

  Examples of the organic filler include acrylic resin, cellulose resin, and polystyrene resin.

  Examples of the inorganic filler include particles such as silicon dioxide, aluminum hydroxide, aluminum nitride, silicon nitride, aluminum oxide, zirconium oxide, silicon carbide, and glass.

The volume average particle diameter of the organic filler or inorganic filler is preferably 0.01 to 50 μm.
In the present invention, the volume average particle diameter of the filler can be measured by a laser diffraction scattering method.

  Examples of other metal alkoxide compounds include titanium alkoxide, zirconium alkoxide, and silicon alkoxide.

  The composition for forming a passivation layer of the present invention contains at least one oxide selected from the group consisting of Al, Nb, Ta, V, Y, and Hf (hereinafter referred to as “specific oxide”). May be. Since the specific oxide is an oxide generated by heat-treating (sintering) the compound of formula (I), the passivation layer formed from the composition for forming a passivation layer containing the specific oxide has an excellent passivation effect. Is expected to be played.

The viscosity of the composition for forming a passivation layer of the present invention is not particularly limited, and can be appropriately selected depending on a method for applying the composition to a semiconductor substrate. For example, the viscosity (25 ° C.) of the composition for forming a passivation layer can be 0.01 to 100,000 Pa · s. Among these, from the viewpoint of pattern formability, the viscosity of the composition for forming a passivation layer is preferably 0.1 to 10,000 Pa · s. The viscosity is measured at 25 ° C. and a shear rate of 1.0 s ⁻¹ using a rotary shear viscometer.

There is no restriction | limiting in particular in the manufacturing method of the said composition for passivation layer formation. For example, the specific compound represented by the general formula (I), the organic compound represented by (II), the compound represented by the general formula (III) contained as necessary, a liquid medium, and a resin Etc. can be produced by mixing them by a commonly used mixing method.
The components contained in the composition for forming a passivation layer and the content of each component are determined by thermal analysis such as TG / DTA, spectral analysis such as NMR and IR, and chromatographic analysis such as HPLC and GPC. Can be confirmed.

<Semiconductor substrate with passivation layer>
The semiconductor substrate with a passivation layer of the present invention includes a semiconductor substrate and a passivation layer that is a heat treatment product of the composition for forming a passivation layer of the present invention provided on at least a part of at least one surface of the semiconductor substrate. The semiconductor substrate with a passivation layer of the present invention exhibits an excellent passivation effect by having a passivation layer that is a heat-treated product of the composition for forming a passivation layer (composition layer) of the present invention.

The semiconductor substrate is not particularly limited, and can be appropriately selected from those usually used according to the purpose. Examples of the semiconductor substrate include those obtained by doping (diffusing) p-type impurities or n-type impurities into silicon, germanium, or the like. 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 layer is formed is a semiconductor substrate having 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, the thickness of the semiconductor substrate can be 50 to 1000 μm, and preferably 75 to 750 μm.

The thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and can be appropriately selected depending on the purpose. For example, the thickness is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, and still more preferably 15 nm to 20 μm.
In addition, the average thickness of the formed passivation layer was measured by measuring the thickness at three points by an ordinary method using an interference film thickness meter (for example, Filmetrics F20 film thickness measurement system), and the arithmetic average value thereof Calculated.

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

<Method for manufacturing semiconductor substrate with passivation layer>
The method for producing a semiconductor substrate with a passivation layer of the present invention comprises a step of forming a composition layer by applying the composition for forming a passivation layer of the present invention to at least a part of at least one surface of a semiconductor substrate, and the composition Forming a passivation layer by heat-treating (baking) the physical layer. The manufacturing method may further include other steps as necessary.
By using the composition for forming a passivation layer of the present invention, a passivation layer having excellent pattern forming properties and an excellent passivation effect can be formed by a simple method.

  The method for producing a semiconductor substrate with a passivation layer of the present invention 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 passivation layer forming composition of the present invention 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 cleaning method using an alkaline aqueous solution, a generally known cleaning method using RCA cleaning or the like can be exemplified. For example, by immersing the semiconductor substrate in a mixed solution of ammonia water and hydrogen peroxide solution and treating at 60 to 80 ° C., organic substances and particles can be removed and washed. The cleaning time is preferably 10 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes.

  There is no particular limitation on the method of forming the composition layer by applying the composition for forming a passivation layer of the present invention on a semiconductor substrate. For example, the method of providing the composition for forming a passivation layer of the present invention on a semiconductor substrate can be exemplified using a known coating method or the like. Specific examples include an immersion method, a screen printing method, an inkjet method, a dispenser method, a spin coating method, a brush coating method, a spray method, a doctor blade method, and a roll coating method. Among these, from the viewpoint of pattern formability and productivity, a screen printing method, an inkjet method, and the like are preferable.

  The application amount of the composition for forming a passivation layer of the present invention can be appropriately selected according to the purpose. For example, the thickness of the passivation layer to be formed can be appropriately adjusted so as to have a desired thickness.

A passivation layer is formed on a semiconductor substrate by heat-treating (baking) the composition layer formed by the composition for forming a passivation layer to form a heat-treated material layer (fired material layer) derived from the composition layer. can do.
The heat treatment (firing) conditions of the composition layer are the compound (I) contained in the composition layer and, if necessary, the organoaluminum compound, a metal oxide or composite oxide that is the heat treated product (firing product). There is no particular limitation as long as it can be converted to. In order to effectively give a fixed charge to the passivation layer and obtain a more excellent passivation effect, specifically, the heat treatment (firing) temperature is preferably 300 to 900 ° C, more preferably 450 to 800 ° C. The heat treatment (firing) time can be appropriately selected according to the heat treatment (firing) temperature and the like. For example, it can be 0.1 to 10 hours, and preferably 0.2 to 5 hours.

  In the method for producing a semiconductor substrate with a passivation layer of the present invention, the composition for forming a passivation layer is formed by applying the composition for forming a passivation layer of the present invention to a semiconductor substrate and before forming the passivation layer by heat treatment (firing). You may further have the process of drying the composition layer which consists of a thing. By including the step of drying the composition layer, a passivation layer having a more uniform passivation effect can be formed.

  If the step of drying the composition layer is capable of removing at least a part of water contained in the composition for forming a passivation layer and at least a part of a liquid medium that may be contained in the composition for forming a passivation layer. There is no particular restriction. The drying treatment can be, for example, a heat treatment at 30 to 250 ° C. for 1 to 60 minutes, and is preferably a heat treatment at 40 to 220 ° C. for 3 to 40 minutes. The drying treatment may be performed under normal pressure or under reduced pressure.

  When the composition for forming a passivation layer contains a resin, the method for manufacturing a semiconductor substrate with a passivation layer according to the present invention provides the composition for forming a passivation layer, and then before the step of forming the passivation layer by heat treatment (firing). The composition layer comprising the composition for forming a passivation layer may further include a step of degreasing the composition layer. By having a step of degreasing the composition layer, a passivation layer having a more uniform passivation effect can be formed.

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

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

  It does not restrict | limit especially as a semiconductor substrate which provides the composition for formation of the passivation layer of this invention, According to the objective, it can select suitably from what is normally used. As the semiconductor substrate, those described in the section of the semiconductor substrate with a passivation layer of the present invention can be used, and those that can be suitably used are also the same. It is preferable that the surface of the semiconductor substrate provided with the passivation layer of the present invention is the back surface of the solar cell element.

The thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and can be appropriately selected according to the purpose. For example, the average thickness of the passivation layer is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, and still more preferably 15 nm to 20 μm.
There is no restriction | limiting in the shape and magnitude | size of the solar cell element of this invention. For example, it is preferable that one side is a substantially square of 125 to 156 mm.

<Method for producing solar cell element>
The method for producing a solar cell element according to the present invention comprises the composition for forming a passivation layer according to the present invention on at least a part of at least one surface of a semiconductor substrate having a pn junction formed by pn junction of a p-type layer and an n-type layer. On the at least one of the p-type layer and the n-type layer, a step of applying a product to form a composition layer, a step of heat-treating (firing) the composition layer to form a passivation layer, Arranging the electrodes. The method for manufacturing a solar cell element of the present invention may further include other steps as necessary.

  By using the composition for forming a passivation layer of the present invention, a solar cell element excellent in conversion efficiency can be produced by a simple method.

  As a method for disposing the electrode on at least one of the p-type layer and the n-type layer in the semiconductor substrate, a commonly used method can be employed. An electrode can be manufactured by applying a paste for forming an electrode such as a silver paste or an aluminum paste to a desired region of a semiconductor substrate and performing a heat treatment (firing) as necessary.

The surface of the semiconductor substrate provided with the passivation layer of the present invention 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 a passivation layer using the composition for forming a passivation layer of the present invention are the same as the method for manufacturing a semiconductor substrate with a passivation layer described above, and the preferred embodiments are also the same.

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

  In FIG. 1A, the p-type semiconductor substrate 1 is washed with an alkaline aqueous solution to remove organic substances, particles, and the like on the surface of the p-type semiconductor substrate 1. Thereby, the passivation effect improves more. As a cleaning method using an alkaline aqueous solution, a method using generally known RCA cleaning and the like can be mentioned.

  Thereafter, as shown in FIG. 1B, the surface of the p-type semiconductor substrate 1 is subjected to alkali etching or the like to form irregularities (also referred to as texture) on the surface. Thereby, reflection of sunlight can be suppressed on the light receiving surface side. For alkali etching, an etching solution composed of NaOH and IPA (i-propyl alcohol) can be used.

Next, as shown in FIG. 1 (3), by thermally diffusing phosphorus or the like on the surface of the p-type semiconductor substrate 1, an n ⁺ -type diffusion layer 2 is formed with a thickness on the order of submicrons, A pn junction is formed at the boundary with the p-type bulk portion.

As a method for diffusing phosphorus, for example, a method of performing several tens of minutes at 800 to 1000 ° C. in a mixed gas atmosphere of phosphorus oxychloride (POCl ₃ ), nitrogen and oxygen can be cited. In this method, since phosphorus is diffused using a mixed gas, the n ⁺ -type diffusion layer 2 is formed not only on the light receiving surface (front surface) but also on the back surface and side surfaces (not shown) as shown in FIG. Is formed. A PSG (phosphosilicate glass) layer 3 is formed on the n ⁺ -type diffusion layer 2. Therefore, side etching is performed to remove the side PSG layer 3 and the n ⁺ -type diffusion layer 2.

Thereafter, as shown in FIG. 1 (4), the PSG layer 3 on the light receiving surface and the back surface is removed using an etching solution such as hydrofluoric acid. Further, as shown in FIG. 1 (5), the back surface is separately etched to remove the n ⁺ -type diffusion layer 2 on the back surface.

Then, as shown in FIG. 1 (6), an antireflection film 4 such as silicon nitride is formed on the n ⁺ -type diffusion layer 2 on the light-receiving surface by a PECVD (Plasma Enhanced Chemical Vapor Deposition) method or the like at a thickness of about 90 nm. Provide.

  Next, as shown in FIG. 1 (7), after applying the passivation layer forming composition of the present invention to a part of the back surface by screen printing or the like, heat treatment (baking) is performed at a temperature of 300 to 900 ° C. after drying. Then, the passivation layer 5 is formed.

In FIG. 5, an example of the formation pattern of the passivation layer in the back surface is shown as a schematic plan view. FIG. 7 is an enlarged schematic plan view of a portion A in FIG. FIG. 8 is an enlarged schematic plan view of a portion B in FIG. In the case of the passivation layer formation pattern shown in FIG. 5, as can be seen from FIGS. 7 and 8, the back surface passivation layer 5 is formed in a dot shape except for the portion where the back surface output extraction electrode 7 is formed in a later step. The pattern semiconductor substrate 1 is formed with an exposed pattern. The pattern of the dot-shaped openings is defined by the dot diameter (L _a ) and the dot interval (L _b ), and is preferably arranged regularly. Dot diameter _{(L a)} and the dot interval _{(L b)} is can be arbitrarily set, in view of suppressing the recombination of the passivation effect and minority carriers, that _{L a} is _{L b} in 5μm~2mm is 10μm~3mm It is more preferable that L _a is 10 μm to 1.5 mm and L _b is 20 μm to 2.5 mm, and it is more preferable that L _a is 20 μm to 1.3 mm and L _b is 30 μm to 2 mm.

In the case where the composition for forming a passivation layer has an excellent pattern forming property, the dot diameter (L _a ) and the dot interval (L _b ) are more regularly arranged in this dot-like opening pattern. For this reason, a preferable dot-shaped opening pattern can be formed by suppressing minority carrier recombination, and the power generation efficiency of the solar cell element is improved.

  Here, a passivation layer having a desired shape is formed by applying the passivation layer forming composition to a portion where the passivation layer is to be formed (portion other than the dot-shaped opening) and heat-treating (sintering). . On the other hand, the passivation layer forming composition can be applied to the entire surface including the dot-shaped opening, and the passivation layer in the dot-shaped opening can be selectively removed by laser, photolithography, etc. after heat treatment (firing). . Alternatively, the passivation layer forming composition can be selectively applied by previously masking a portion such as a dot-shaped opening where the passivation layer forming composition is not desired to be applied with a mask material.

  Next, as shown in FIG. 1 (8), a silver electrode paste containing glass particles is applied to the light receiving surface by screen printing or the like. FIG. 4 is a schematic plan view showing an example of the light receiving surface of the solar cell element. As shown in FIG. 4, the light receiving surface electrode includes a light receiving surface current collecting electrode 8 and a light receiving surface output extraction electrode 9. In order to secure a light receiving area, it is necessary to suppress the formation area of these light receiving surface electrodes. In addition, from the viewpoints of resistivity and productivity of the light receiving surface electrode, the width of the light receiving surface current collecting electrode 8 is preferably 10 to 250 μm, and the width of the light receiving surface output extraction electrode 9 is preferably 100 μm to 2 mm. In FIG. 4, two light receiving surface output extraction electrodes 9 are provided. However, from the viewpoint of minority carrier extraction efficiency (power generation efficiency), the number of light receiving surface output extraction electrodes 9 may be three or four. it can.

  On the other hand, as shown in FIG. 1 (8), an aluminum electrode paste containing glass powder and a silver electrode paste containing glass particles are applied to the back surface by screen printing or the like. FIG. 9 is a schematic plan view showing an example of the back surface of the solar cell element. Although the width | variety of the back surface output extraction electrode 7 is not restrict | limited in particular, From viewpoints, such as connectivity of the wiring material in the manufacturing process of a later solar cell, it is preferable that the width | variety of the back surface output extraction electrode 7 is 100 micrometers-10 mm.

  After applying the electrode paste to the light receiving surface and the back surface, after drying, the light receiving surface and the back surface are both heat-treated (fired) at a temperature of about 450 to 900 ° C. in the atmosphere, and the light receiving surface collecting electrode 8 is applied to the light receiving surface. The back surface collecting aluminum electrode 6 and the back surface output extracting electrode 7 are formed on the back surface, respectively.

After heat treatment (firing), as shown in FIG. 1 (9), on the light receiving surface, the glass particles contained in the silver electrode paste forming the light receiving surface electrode react with the antireflection film 4 (fire through), The light-receiving surface electrode (light-receiving surface current collecting electrode 8, light-receiving surface output extraction electrode 9) and the n ⁺ -type diffusion layer 2 are electrically connected (ohmic contact). On the other hand, on the back surface, in the portion where the p-type semiconductor substrate 1 is exposed in a dot shape (the portion where the passivation layer 5 is not formed), the aluminum in the aluminum electrode paste is transferred into the p-type semiconductor substrate 1 by heat treatment (firing). By diffusing, the p ⁺ -type diffusion layer 10 is formed. In the present invention, by using the composition for forming a passivation layer of the present invention having excellent pattern formability, a passivation layer having excellent passivation effect can be formed by a simple method, and a solar cell element having excellent power generation performance is produced. be able to.

FIG. 2 is a cross-sectional view showing another example of a method for manufacturing a solar cell element having a passivation layer according to this embodiment, and the n ⁺ -type diffusion layer 2 on the back surface is removed by an etching process. After that, the solar cell element can be manufactured in the same manner as in FIG. 1 except that the back surface is further flattened. When flattening, a technique such as immersing the back surface of the semiconductor substrate in a mixed solution of nitric acid, hydrofluoric acid and acetic acid or a potassium hydroxide solution can be used.

FIG. 3 is a cross-sectional view showing a process diagram illustrating another example of a method for manufacturing a solar cell element having a passivation layer according to the present embodiment. This method is the same as the method of FIG. 1 until the step of forming the texture structure, the n ⁺ -type diffusion layer 2 and the antireflection film 4 on the p-type semiconductor substrate 1 (FIGS. 3 (19) to (24)). .

  After the antireflection film 4 is formed, a passivation layer forming composition 5 is applied as shown in FIG. In FIG. 6, an example of the formation pattern of the passivation layer in the back surface is shown as a schematic plan view. In the formation pattern of the passivation layer shown in FIG. 6, dot-like openings are arranged on the entire back surface, and dot-like openings are also arranged on the portion where the back-surface output extraction electrode is formed in a later step.

Thereafter, as shown in FIG. 3 (26), boron or aluminum is diffused from the portion where the p-type semiconductor substrate 1 is exposed in the form of dots on the back surface (the portion where the passivation layer 5 is not formed), and p ⁺ -type diffusion is performed. Layer 10 is formed. When boron is diffused when forming the p ⁺ -type diffusion layer 10, a method of treating at a temperature around 1000 ° C. in a gas containing boron trichloride (BCl ₃ ) can be used. However, since the method of gas diffusion is the same as in the case of using phosphorus oxychloride, the p ⁺ -type diffusion layer 10 is formed on the light receiving surface, the back surface, and the side surface of the substrate. It is necessary to take measures such as masking the portions other than the openings to prevent boron from diffusing into unnecessary portions of the p-type semiconductor substrate 1.

In addition, when aluminum is diffused when forming the p ⁺ -type diffusion layer 10, the aluminum paste is applied to the dot-shaped opening, and this is heat-treated (fired) at a temperature of 450 to 900 ° C. A method may be used in which aluminum is diffused from the portion to form the p ⁺ -type diffusion layer 10 and then the heat-treated product layer (baked product layer) made of aluminum paste on the p ⁺ -type diffusion layer 10 is etched with hydrochloric acid or the like. .

  Next, as shown in FIG. 3 (27), aluminum is physically vapor-deposited on the entire back surface to form the back surface collecting aluminum electrode 11.

  Thereafter, as shown in FIG. 3 (28), a silver electrode paste containing glass particles is applied to the light receiving surface by screen printing or the like, and a silver electrode paste containing glass particles is applied to the back surface by screen printing or the like. . The silver electrode paste on the light receiving surface is applied in a pattern according to the shape of the light receiving surface electrode shown in FIG. 4, and the silver electrode paste on the back surface is applied in a pattern according to the shape of the back electrode shown in FIG.

After applying the electrode paste to the light receiving surface and the back surface, respectively, after drying, the light receiving surface and the back surface are both heat-treated (fired) at a temperature of about 450 to 900 ° C. in the atmosphere, and as shown in FIG. A light receiving surface collecting electrode 8 and a light receiving surface output extraction electrode 9 are formed on the surface, and a back surface output extraction electrode 7 is formed on the back surface. At this time, the light receiving surface electrode and the n ⁺ -type diffusion layer 2 are electrically connected on the light receiving surface, and the back surface collecting aluminum electrode 11 and the back surface output extraction electrode 7 formed by vapor deposition are electrically connected on the back surface. Is done.

<Solar cell>
The solar cell of the present invention includes at least one of the solar cell elements of the present invention, and is configured by arranging a wiring material on the electrode of the solar cell element. That is, the solar cell of this invention has the said solar cell element and the wiring material arrange | positioned on the said electrode of the said solar cell element.
If necessary, the solar cell of the present invention is 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 technical field.

  FIG. 10 is a diagram for explaining an example of a method for producing a solar cell of the present invention. For example, as shown in FIG. 10, the solar cell of the present invention is formed by laminating a glass plate 16, a sealing material 14, a solar cell element 12 connected to a wiring member 13, a sealing material 14, and a back sheet 15 in this order. Then, this laminate is vacuum laminated at a temperature of 140 ° C. for 5 minutes using a vacuum laminator (for example, NP Corporation, “LM-50 × 50-S”) so that a part of the wiring member is exposed. Can be manufactured.

  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 passivation layer)
As a compound represented by the general formula (I), 2.997 g of pentaethoxyniobium (Hokuko Chemical Co., Ltd., structural formula: Nb (OC ₂ H ₅ ) ₅ , molecular weight: 318.2) is represented by the general formula (II). 17.463 g of isobornylcyclohexanol (Nippon Terpene Chemical Co., Ltd., trade name: Tersolve MTPH) as the organic compound represented, and ethyl acetoacetate aluminum diisopropylate (Kawaken) as the compound represented by the general formula (III) A composition 1 for forming a passivation layer was prepared by mixing 3.003 g of Fine Chemical Co., Ltd. (trade name: ALCH) and 6.543 g of terpineol as a solvent and kneading for 5 minutes.

(Thixo ratio)
Immediately after preparation (within 12 hours) of the composition 1 for forming a passivation layer prepared above, a rotary shear viscometer (AntonPaar, MCR301) is equipped with a cone plate (diameter 50 mm, cone angle 1 °). The measurement was performed at a temperature of 25.0 ° C. and shear rates of 10 s ⁻¹ and 1000 s ⁻¹ .
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 2.5 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 2.5 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Formation of passivation layer)
As the semiconductor substrate, a single crystal p-type silicon substrate (SUMCO, 50 mm square, thickness: 770 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 (Kanto Chemical Co., Ltd., Frontier Cleaner-A01).
Thereafter, the passivation layer forming composition 1 was applied to the silicon substrate, and the silicon substrate was heated at 150 ° C. for 5 minutes to evaporate the liquid medium, thereby drying. Next, the silicon substrate was heat-treated (baked) at a temperature of 700 ° C. for 10 minutes and then allowed to cool at room temperature (25 ° C.). The heat treatment (firing) was performed using a diffusion furnace (ACCURON CQ-1200, Hitachi Kokusai Electric Inc.) under conditions of a maximum temperature of 700 ° C. and a holding time of 10 minutes in an air atmosphere.

(Measurement of effective lifetime)
The effective lifetime (LT1) (μs) of the evaluation substrate obtained above is reflected at a room temperature (25 ° C.) using a lifetime measurement device (Nippon Semi-Lab Co., Ltd., WT-2000PVN). It was measured by. The effective lifetime (LT1) of the region to which the composition for forming a passivation layer of the obtained evaluation substrate was applied was 1312 μs.

(Effective lifetime retention after 10 days)
The effective lifetime retention ratio obtained from the effective lifetime (LT1) (μs) obtained above and the effective lifetime (LT2) obtained by the same method as described above after 10 days from firing was 95. %Met.

<Example 2>
(Preparation of composition 2 for forming a passivation layer)
Composition for forming a passivation layer by mixing 3.015 g of pentaethoxyniobium, 20.481 g of isobornylcyclohexanol, 2.988 g of ethyl acetoacetate aluminum diisopropylate, and 3.516 g of terpineol and kneading for 5 minutes. Product 2 was prepared.

(Thixo ratio)
The composition 2 for forming a passivation layer prepared above was sheared immediately after preparation (within 12 hours), and a rotary shear viscometer was fitted with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C. respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 7.3 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 7.3 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the composition 2 for forming a passivation layer, and evaluated in the same manner. The effective lifetime was 1305 μs. The effective lifetime retention rate after 10 days was 96%.

<Example 3>
(Preparation of composition 3 for forming a passivation layer)
Composition for forming a passivation layer by mixing 2.998 g of pentaethoxyniobium, 13.996 g of isobornylcyclohexanol, 3.045 g of ethyl acetoacetate aluminum diisopropylate, and 9.963 g of terpineol and kneading for 5 minutes. Product 3 was prepared.

(Thixo ratio)
The composition 3 for forming a passivation layer prepared above was sheared immediately after preparation (within 12 hours), and a rotary shear viscometer was fitted with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C., respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 0.8 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 0.8 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the passivation layer forming composition 3 and evaluated in the same manner. The effective lifetime was 1298 μs. The effective lifetime retention rate after 10 days was 97%.

<Example 4>
(Preparation of passivation layer forming composition 4)
Composition for forming a passivation layer by mixing 1.503 g of pentaethoxyniobium, 19.409 g of isobornylcyclohexanol, 1.504 g of ethyl acetoacetate aluminum diisopropylate and 7.598 g of terpineol and kneading for 5 minutes. Product 4 was prepared.

(Thixo ratio)
The composition 4 for forming the passivation layer prepared above was sheared immediately after preparation (within 12 hours). A rotary shear viscometer was equipped with a cone plate (diameter 50 mm, cone angle 1 °), and the temperature was 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C. respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 2.6 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 2.5 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the composition 4 for forming a passivation layer, and evaluated in the same manner. The effective lifetime was 1333 μs. The effective lifetime retention rate after 10 days was 97%.

<Example 5>
(Preparation of composition 5 for forming a passivation layer)
Composition for forming a passivation layer by mixing 1.496 g of pentaethoxyniobium, 22.955 g of isobornylcyclohexanol, 1.557 g of ethyl acetoacetate aluminum diisopropylate and 3.994 g of terpineol and kneading for 5 minutes. Product 5 was prepared.

(Thixo ratio)
The composition 5 for forming a passivation layer prepared above was subjected to shear viscosity immediately after preparation (within 12 hours), and a rotary shear viscometer was fitted with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C., respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 10.9 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 10.9 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the composition 5 for forming a passivation layer, and evaluated in the same manner. The effective lifetime was 1345 μs. The effective lifetime retention rate after 10 days was 95%.

<Example 6>
(Preparation of passivation layer forming composition 6)
Composition for forming a passivation layer by mixing 2.227 g of pentaethoxyniobium, 18.537 g of isobornylcyclohexanol, 2.223 g of ethyl acetoacetate aluminum diisopropylate and 7.004 g of terpineol and kneading for 5 minutes. Product 6 was prepared.

(Thixo ratio)
The composition 6 for forming a passivation layer prepared above was subjected to a shear viscosity immediately after preparation (within 12 hours), and a rotary shear viscometer was fitted with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C., respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 3.7 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 3.6 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the composition 6 for forming a passivation layer, and evaluated in the same manner. The effective lifetime was 1324 μs. The effective lifetime retention rate after 10 days was 95%.

<Example 7>
(Preparation of Passivation Layer-Forming Composition 7)
A composition for forming a passivation layer is prepared by mixing 2.266 g of pentaethoxyniobium, 23.945 g of isobornylcyclohexanol, 2.274 g of ethyl acetoacetate aluminum diisopropylate and 1.504 g of terpineol and kneading for 5 minutes. Product 7 was prepared.

(Thixo ratio)
The shear viscosity of the composition 7 for forming a passivation layer prepared above was set immediately after the preparation (within 12 hours), and a rotary shear viscometer was equipped with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C. respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 24.9 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 24.9 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the passivation layer forming composition 7, and evaluated in the same manner. The effective lifetime was 1288 μs. The effective lifetime retention rate after 10 days was 97%.

<Example 8>
(Preparation of passivation layer forming composition 8)
Composition for forming a passivation layer by mixing 2.376 g of pentaethoxyniobium, 20.877 g of isobornylcyclohexanol, 2.298 g of ethyl acetoacetate aluminum diisopropylate and 4.483 g of terpineol and kneading for 5 minutes. Product 8 was prepared.

(Thixo ratio)
The composition 8 for forming a passivation layer prepared above was sheared immediately after preparation (within 12 hours), and a rotary shear viscometer was fitted with a cone plate (diameter 50 mm, cone angle 1 °), and the temperature was 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C., respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 6.4 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 6.4 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 1.0.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the passivation layer forming composition 8 and evaluated in the same manner. The effective lifetime was 1304 μs. The effective lifetime retention rate after 10 days was 95%.

<Comparative Example 1>
(Preparation of composition C1 for forming a passivation layer)
100.0 g of ethyl cellulose and 900 g of terpineol were mixed and stirred at 150 ° C. for 1 hour to prepare a 10 mass% ethyl cellulose solution. Separately, 4.143 g of pentaethoxyniobium, 4.278 g of ethyl acetoacetate aluminum diisopropylate and 6.520 g of terpineol are mixed, and then 15.061 g of 10% by weight ethylcellulose solution is mixed for 5 minutes. A composition C1 for forming a passivation layer was prepared as a colorless and transparent solution by kneading.

(Thixo ratio)
The composition C1 for forming a passivation layer prepared above was sheared immediately after preparation (within 12 hours), and a rotary shear viscometer was equipped with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C., respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 41.1 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 0.6 Pa · s. The thixo ratio (η ₁ / η ₂ ) was 69 when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ .

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on the silicon substrate pretreated with the passivation layer forming composition C1, and evaluated in the same manner. The effective lifetime was 1077 μs. The effective lifetime retention rate after 10 days was 6%.

<Comparative example 2>
(Preparation of passivation layer forming composition C2)
2.229 g of pentaethoxyniobium, 2.2235 g of ethyl acetoacetate aluminum diisopropylate, and 10.506 g of terpineol are mixed, and then 15.032 g of the 10 mass% ethylcellulose solution of Comparative Example 1 is mixed for 5 minutes. A composition C2 for forming a passivation layer was prepared as a colorless and transparent solution by kneading.

(Thixo ratio)
The composition C2 for forming a passivation layer prepared above was sheared immediately after preparation (within 12 hours). A rotary shear viscometer was equipped with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C., respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 31.3 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 0.4 Pa · s. The thixo ratio (η ₁ / η ₂ ) when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ was 78.3.

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the passivation layer forming composition C2, and evaluated in the same manner. The effective lifetime was 954 μs. The effective lifetime retention rate after 10 days was 15%.

<Comparative Example 3>
(Preparation of composition C3 for forming a passivation layer)
1.542 g of pentaethoxyniobium, 1.503 g of ethyl acetoacetate aluminum diisopropylate, and 25.364 g of terpineol were mixed, and then 1.591 g of the 10 mass% ethylcellulose solution of Comparative Example 1 was mixed for 5 minutes. A composition C3 for forming a passivation layer was prepared as a colorless and transparent solution by kneading.

(Thixo ratio)
The composition C1 for forming a passivation layer prepared above was sheared immediately after preparation (within 12 hours), and a rotary shear viscometer was equipped with a cone plate (diameter 50 mm, cone angle 1 °) at a temperature of 25.0. The measurement was carried out at a temperature of 10 s ⁻¹ and 1000 s ⁻¹ at ⁰ ° C. respectively.
The shear viscosity (η ₁ ) at a shear rate of 10 s ⁻¹ was 0.1 Pa · s, and the shear viscosity (η ₂ ) at a shear rate of 1000 s ⁻¹ was 0.01 Pa · s. The thixo ratio (η ₁ / η ₂ ) was 10.0 when the shear viscosity was 10 s ⁻¹ and 1000 s ⁻¹ .

(Effective lifetime and effective lifetime retention rate)
A passivation layer was formed in the same manner as in Example 1 on a silicon substrate pretreated with the passivation layer forming composition C3 and evaluated in the same manner. The effective lifetime was 1150 μs. The effective lifetime retention rate after 10 days was 51%.
The results of Examples 1 to 8 and Comparative Examples 1 to 3 are summarized in Table 1.

  As shown in Examples 1 to 8, a passivation layer having a good lifetime and lifetime retention rate when a composition for forming a passivation layer containing a specific organic compound represented by the general formula (II) is used. It was found that can be formed. On the other hand, Comparative Examples 1 to 3 not containing the specific organic compound represented by the general formula (II) had a low lifetime retention rate.

1: p-type semiconductor substrate, 2: n ⁺ -type diffusion layer, 3: PSG (phosphosilicate glass) layer, 4: antireflection film, 5: composition for forming passivation, 6: aluminum electrode paste, or heat treatment ( Baked back surface collecting aluminum electrode, 7: back surface output extraction electrode paste, or back surface output extraction electrode heat-treated (baked), 8: light receiving surface current collecting electrode paste, or heat-treated (fired) received light Electrode for surface current collection, 9: Light receiving surface output extraction electrode paste, or light reception surface output extraction electrode obtained by heat treatment (baking), 10: p ⁺ type diffusion layer, 11: Aluminum electrode for back surface current collection, 12: Solar cell Element: 13: Wiring member, 14: Sealing material, 15: Back sheet, 16: Glass plate.

Claims (7)

A compound represented by the following general formula (I) and an organic compound represented by the following general formula (II), wherein the content of the general formula (II) is 100% by mass of the composition for forming a passivation layer The composition for formation of a passivation layer which is 30-90 mass% with respect to.

[In General Formula (I), M represents at least one selected from the group consisting of Al, Nb, Ta, V, Y, and Hf. R ¹ independently represents an alkyl group or an aryl group. m represents an integer of 1 to 5. ]

Furthermore, the composition for passivation layer formation of Claim 1 containing the compound represented with the following general formula (III).

[In General Formula (III), each R ² independently represents an alkyl group. n represents an integer of 1 to 3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ³ , R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group. ] A semiconductor substrate;
A semiconductor substrate with a passivation layer, comprising: a passivation layer that is a heat treatment product of the composition for forming a passivation layer according to claim 1, provided on at least a part of at least one surface of the semiconductor substrate. A step of applying a passivation layer forming composition according to claim 1 or 2 to at least a part of at least one surface of a semiconductor substrate to form a composition layer;
Heat-treating the composition layer to form a passivation layer;
The manufacturing method of the semiconductor substrate with a passivation layer which has this. a semiconductor substrate having a pn junction formed by p-type junction of a p-type layer and an n-type layer;
A passivation layer, which is a heat treatment product of the composition for forming a passivation layer according to claim 1 or 2, provided on at least a part of at least one surface of the semiconductor substrate;
An electrode disposed on at least one of the p-type layer and the n-type layer;
A solar cell element having The composition for forming a passivation layer according to claim 1 or 2 is applied to at least a part of at least one surface of a semiconductor substrate having a pn junction formed by pn junction of a p-type layer and an n-type layer. Forming a composition layer,
Heat-treating the composition layer to form a passivation layer;
Disposing an electrode on at least one of the p-type layer and the n-type layer;
The manufacturing method of the solar cell element which has this. A solar cell element according to claim 5;
And a wiring material disposed on the electrode of the solar cell element.

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