JP6946210B2 - Diffusion agent composition and semiconductor substrate manufacturing method - Google Patents

Description

The present invention relates to a diffusing agent composition used for diffusing an impurity diffusing component in a semiconductor substrate, and a method for manufacturing a semiconductor substrate using the diffusing agent composition.

Semiconductor substrates used for semiconductor elements such as transistors, diodes, and solar cells are manufactured by diffusing impurity diffusion components such as phosphorus and boron into the semiconductor substrate. Regarding such a semiconductor substrate, when manufacturing a semiconductor substrate for a multigate element such as a Fin-FET or a nanowire FET, for example, with respect to a semiconductor substrate having a three-dimensional structure having minute voids on the nanometer scale on its surface. The impurities may be diffused.

Here, as a method for diffusing an impurity diffusion component on a semiconductor substrate, for example, an ion implantation method (see, for example, Patent Document 1) and a CVD method (see, for example, Patent Document 2) are known. In the ion implantation method, ionized impurity diffusion components are implanted into the surface of the semiconductor substrate. In the CVD method, an oxide film such as silicon oxide doped with an impurity diffusion component such as phosphorus or boron is formed on the semiconductor substrate by CVD, and then the semiconductor substrate having the oxide film is heated by an electric furnace or the like. , The impurity diffusion component is diffused from the oxide film to the semiconductor substrate.

Japanese Unexamined Patent Publication No. 06-318559 International Publication No. 2014/064873

However, in the ion implantation method as described in Patent Document 1, when light ions such as B (boron) are implanted into the semiconductor substrate, point defects and point defect clusters are formed in a region near the surface of the substrate. Cheap. For example, when an element such as a CMOS image sensor is formed by diffusing an impurity diffusion component on a semiconductor substrate by an ion implantation method, the occurrence of such a defect directly leads to a decrease in the performance of the element.

Further, the semiconductor substrate has a three-dimensional structure for forming a multi-gate element called a Fin-FET, which includes, for example, a plurality of source fins, a plurality of drain fins, and a gate orthogonal to those fins. When a nanoscale three-dimensional structure such as the above is provided on the surface, in the ion implantation method, uniform ions are generated on the side surface and the upper surface of the fin or the gate, or the entire inner surface of the recess surrounded by the fin and the gate. It is difficult to implant.
The non-uniformity of diffusion of impurities into a semiconductor substrate having a nanoscale three-dimensional structure is also a factor in reducing the performance of elements such as the CMOS image sensor described above.

When the impurity diffusion component is diffused into a semiconductor substrate having a nanoscale three-dimensional structure by an ion implantation method, even if uniform ion implantation is possible, there are the following problems. For example, when a logic LSI device or the like is formed using a semiconductor substrate having a three-dimensional pattern having fine fins, crystals of a substrate material such as silicon are easily destroyed by ion implantation. Such crystal damage is considered to cause problems such as variations in device characteristics and generation of standby leakage current.

In a semiconductor substrate having a nanoscale three-dimensional structure on its surface, it is conceivable to use a coating type diffusing agent composition in order to improve the uniformity of diffusion of impurity diffusing components.
In a substrate having a three-dimensional structure having nanoscale minute voids on its surface, if the coating type diffusing agent composition can be uniformly applied to the entire surface including the entire inner surface of the minute voids, such a three-dimensional surface can be obtained. Impurities such as boron can be uniformly diffused in the semiconductor substrate.

However, when a diffusing agent composition containing a boron compound as an impurity diffusion component is applied onto a semiconductor substrate, a film is not formed on the surface of the semiconductor substrate and minute particles are formed or fogging occurs, resulting in a film thickness. Tends to form a uniform coating film.
If such a defect occurs during the formation of the coating film, it is difficult to uniformly diffuse impurities on the surface of the semiconductor substrate.

Further, it is desired that the coating type diffusing agent composition can satisfactorily diffuse impurities even when the heating and cooling cycles are shortened and the heating is performed at a low temperature. It has become more necessary to control the diffusion length with the three-dimensionalization, but it is considered that the diffusion length can be shortened by diffusing by heating at a low temperature.

The present invention has been made in view of the above problems, and is a case where the semiconductor substrate to which the impurity diffusion component is diffused has a three-dimensional structure having nanoscale minute voids on the surface thereof. Even if there is, a uniform coating film having a uniform film thickness and no fogging can be formed on the surface of the semiconductor substrate including the entire inner surface of minute voids, whereby, for example, when heating at a low temperature of 1000 ° C. or lower. Another object of the present invention is to provide a diffusing agent composition capable of diffusing boron in a semiconductor substrate well and uniformly, and a method for producing a semiconductor substrate using the diffusing agent composition.

In the diffusing agent composition containing the impurity diffusing component (A), the present inventors use a first boron compound and a second boron compound, which are two specific boron compounds, as the impurity diffusing component (A). It has been found that the above-mentioned problems can be solved by containing the compound, and the present invention has been completed. More specifically, the present invention provides the following.

（式（ａ２ａ）中、Ｒ^１は、それぞれ独立に水素原子、炭素原子数１〜１０の炭化水素基であり、Ｒ^２は、水素原子、又は炭素原子数１〜１０の炭化水素基であり、ただしＲ^１及びＲ^２の少なくとも一方は炭化水素基であり、Ｒ^３は、炭素原子数１〜１０の２価の脂肪族炭化水素基であり、
式（ａ２ｂ）中、Ｒ^４は、炭素原子数１〜１０の炭化水素基であり、Ｒ^５は、水素原子、又は炭素原子数１〜１０の炭化水素基であり、Ｒ^６は炭素原子数１〜１０の２価の脂肪族炭化水素基であり、
式（ａ２ｃ）中、Ｒ^７は、それぞれ独立に炭素原子数１〜１０の炭化水素基であり、Ｒ^８は、それぞれ独立に水素原子、又は炭素原子数１〜１０の炭化水素基であり、Ｒ^９は、炭素原子数１〜１０の２価の炭化水素基であり、ｐは、０又は１であり、
式（ａ２ｄ）中、Ｒ^１０は、それぞれ独立に水素原子、炭素原子数１〜１０の炭化水素基であり、Ｒ^１１は、それぞれ独立に水素原子、又は炭素原子数１〜１０の炭化水素基であり、ただしＲ^１０及びＲ^１１の少なくとも一方は炭化水素基であり、Ｒ^１２は、それぞれ独立に炭素原子数１〜１０の２価の炭化水素基である。）
で表される化合物からなる群より選択される１種以上である、拡散剤組成物である。 A first aspect of the present invention is a diffusing agent composition used for diffusing impurities into a semiconductor substrate.
Contains the impurity diffusion component (A)
The impurity diffusion component (A) contains a first boron compound (A1) and a second boron compound (A2).
The first boron compound (A1) is produced by boron hydride or hydrolysis.
The following equation (a1e) and equation (a1f):
B (R ^1a ) ₂ OH ... (a1e)
B (R ^1a ) (OH) ₂ ... (a1f)
(In the formula (A1e), and ^{(A1f), R 1a} is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
A boron compound capable of producing one or more compounds selected from the group consisting of the compounds represented by.
The second boron compound (A2) is a boron compound other than the first boron compound (A1), and the following formulas (a2a) to (a2d):

(In the formula (a2a), R ¹ is a hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, respectively, and R ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However ^{, at least one of R 1} and R ² is a hydrocarbon group, and R ³ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.
In the formula (a2b), R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ is a hydrocarbon group having 1 to 10 carbon atoms. It is a divalent aliphatic hydrocarbon group of 1 to 10.
In the formula (a2c), R ⁷ is an independent hydrogen group having 1 to 10 carbon atoms, and R ⁸ is an independent hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ⁹ is a divalent hydrocarbon group having 1 to 10 carbon atoms, and p is 0 or 1.
In the formula (a2d), R ¹⁰ is an independently hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, and R ¹¹ is an independently hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However ^{, at least one of R 10} and R ¹¹ is a hydrocarbon group, and R ¹² is a divalent hydrocarbon group having 1 to 10 carbon atoms independently. )
It is a diffusing agent composition which is one or more selected from the group consisting of a compound represented by.

A second aspect of the present invention is
The formation of a coating film by applying the diffusing agent composition according to the first aspect on the semiconductor substrate, and
This is a method for manufacturing a semiconductor substrate, which comprises diffusing the impurity diffusion component (A) in the diffusing agent composition onto the semiconductor substrate.

According to the present invention, even when the semiconductor substrate for which the impurity diffusion component is diffused has a three-dimensional structure having nanoscale minute voids on its surface, the entire inner surface of the minute voids is provided. A uniform coating film having a uniform film thickness and no fogging can be formed on the surface of the semiconductor substrate containing the above, whereby boron is diffused well and uniformly on the semiconductor substrate even when heated at a low temperature of 1000 ° C. or lower, for example. It is possible to provide a diffusing agent composition that can be used and a method for producing a semiconductor substrate using the diffusing agent composition.

≪Diffusing agent composition≫
A diffusing agent composition used for diffusing impurities into a semiconductor substrate, which contains an impurity diffusing component (A).
The impurity diffusion component (A) contains a first boron compound and a second boron compound, which will be described later.
By using the impurity diffusion component (A), boron can be satisfactorily diffused into the semiconductor substrate by using the diffusing agent composition.
Further, even when the semiconductor substrate to which the impurity diffusing component is diffused by using the above-mentioned diffusing agent composition has a three-dimensional structure having nanoscale minute voids on its surface, even when the surface thereof is provided with a three-dimensional structure. A uniform coating film having a uniform film thickness and no fogging can be formed on the surface of the semiconductor substrate including the entire inner surface of the minute voids. As a result, boron is uniformly diffused on the semiconductor substrate.

Hereinafter, essential or optional components contained in the diffusing agent composition will be described.

[Impurity diffusion component (A)]
The impurity diffusion component (A) can form a diffusion layer by being applied to the surface of a semiconductor substrate, and contains a boron compound. The impurity diffusion component (A) contains a first boron compound (A1) and a second boron compound (A2).

<First boron compound>
The first boron compound (A1) is produced by boron hydride or hydrolysis.
The following equation (a1e) and equation (a1f):
B (R ^1a ) ₂ OH ... (a1e)
B (R ^1a ) (OH) ₂ ... (a1f)
(In the formula (A1e), and ^{(A1f), R 1a} is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
It is a boron compound capable of producing one or more compounds selected from the group consisting of the compounds represented by.
When the impurity diffusion component (A) is applied to a semiconductor substrate to form a film, the first boron compound is hydrolyzed to produce a compound having a B—OH group such as the above formula (a1e) or (a1f). Let me. Boron hydride also produces a decomposition product having a B-OH group by hydrolysis. It is speculated that the compound represented by the above formula (a1e) or (a1f) or the decomposition product of boron hydride may appropriately attract water into the reaction system and assist the hydrolysis reaction. As a result, it is considered that defects in the coating film are suppressed and the uniformity of the film is improved.

In the formula (a1e) and the formula (a1f), R ^1a is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
The hydrocarbon group as R ^1a may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a group in which these are combined.
Preferable specific examples of the hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group and n-. Alkyl groups such as hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, and n-decyl group; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, Cycloalkyl groups such as cyclooctyl group, cyclononyl group, and cyclodecyl group; alkenyl group such as vinyl group, allyl group (2-propenyl group), 3-butenyl group, 4-pentenyl group, and 5-hexenyl group; phenyl group , Arophilic hydrocarbon groups such as naphthalene-1-yl group, naphthalene-2-yl group; aralkyl groups such as benzyl group and phenethyl group; o-tolyl group, m-tolyl group, p-tolyl group, o- Examples thereof include alkyl-substituted aromatic hydrocarbon groups such as an ethylphenyl group, an m-ethylphenyl group, and a p-ethylphenyl group.

（式（ａ１ａ）中、Ｒ^１３及びＲ^１４は、それぞれ独立に炭素原子数１〜１０の炭化水素基であり、ｑは１又は２の整数であり、
式（ａ１ｂ）中、Ｒ^１５は、それぞれ独立に炭素原子数１〜１０の炭化水素基であり、
式（ａ１ｃ）中、Ｒ^１６は、それぞれ独立に炭素原子数１〜１０の炭化水素基であり、Ｒ^１７は、水素原子、又はそれぞれ独立に炭素原子数１〜１０の炭化水素基であり、ｒは１又は２であり、
式（ａ１ｄ）中、Ｒ^１８及びＲ^１９は、それぞれ独立に、水素原子、又は炭素原子数１〜１０の炭化水素である。）
で表される化合物と、からなる群より選択される１種以上が好ましい。
以下、第１ホウ素化合物の好ましい例について説明する。 Examples of the first boron compound (A1) include boron hydride having 2 to 10 boron atoms and the following formulas (a1a) to (a1d):
B (R ¹³ ) _q (OR ¹⁴ ) _(3-q) ... (a1a)

(In the formula (a1a), R ¹³ and R ¹⁴ are each independently a hydrocarbon group having 1 to 10 carbon atoms, and q is an integer of 1 or 2.
Wherein ^{(a1b), R 15} are each independently a hydrocarbon group having 1 to 10 carbon atoms,
In the formula (a1c), R ¹⁶ is a hydrocarbon group having 1 to 10 carbon atoms independently, and R ¹⁷ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms independently. r is 1 or 2
In the formula (a1d), R ¹⁸ and R ¹⁹ are independently hydrogen atoms or hydrocarbons having 1 to 10 carbon atoms. )
It is preferable that one or more selected from the group consisting of the compound represented by.
Hereinafter, preferred examples of the first boron compound will be described.

(Boron hydride)
As the boron hydride having 2 to 10 boron atoms, a well-known boron hydride compound can be used. Preferable examples of boron hydride include borane, diborane, tetraborane, pentaborane, decaborane and the like. Of these, decabolane is preferable because it is easily available and easy to handle.

(Compound represented by the formula (a1a))
In the formula (a1a), R ¹³ and R ¹⁴ are each independently a hydrocarbon group having 1 to 10 carbon atoms, and q is an integer of 1 or 2. q is preferably 1.
In the formula ^{(a1a), R 13,} or ^{R 14} is a plurality, the plurality of ^{R 13,} or ^{R 14} may be different even in the same.
Preferable examples of hydrocarbon groups having 1 to 10 carbon atoms as R ¹³ and R ^{14 are the same as those of R 1a} .

Preferable specific examples of the compound represented by the formula (a1a) include dimethyl methylboronate, diethyl methylboronate, din-propyl methylboronate, di-n-butyl methylboronate, dimethyl ethylboronate, diethyl ethylboronate, and ethylboronic acid. Di-n-propyl, di-n-butyl ethylboronate, dimethyl n-propylboronate, diethyl n-propylboronate, din-propyl n-propylboronate, di-n-butyl n-propylboronate, allylboronic acid Diisopropyl, dimethyl vinylboronate, diethyl vinylboronate, din-propyl vinylboronate, din-butyl vinylboronate, dimethyl phenylboronate, diethyl phenylboronate, din-propyl phenylboronate, and din-butyl phenylboronate Can be mentioned.

(Compound represented by the formula (a1b))
In the formula (a1b), R ¹⁵ is a hydrocarbon group having 1 to 10 carbon atoms independently. In the formula (a1b), the plurality of R ^15s may be the same or different.
Preferable examples of the hydrocarbon group having 1 to 10 carbon atoms as R ^{15 are the same as those of R 1a} .

Specific examples of the compound represented by the formula (a1b) include the following compounds.

(Compound represented by the formula (a1c))
In the formula (a1c), R ¹⁶ and R ¹⁷ are each independently a hydrocarbon group having 1 to 10 carbon atoms, and r is 1 or 2.
Preferable examples of hydrocarbon groups having 1 to 10 carbon atoms as R ¹⁶ and R ^{17 are the same as those of R 1a} .

Specific examples of the compound represented by the formula (a1c) include the following compounds.

In the formula (a1d), R ¹⁸ and R ¹⁹ are independently hydrogen atoms or hydrocarbons having 1 to 10 carbon atoms. )
Preferable examples of hydrocarbon groups having 1 to 10 carbon atoms as R ¹⁸ and R ^{19 are the same as those of R 1a} .
Preferable examples of the compound represented by the formula (a1d) include dimethylaminoborane, diethylaminoborane, din-propylaminoborane, diisopropylaminoborane and the like.

（式（ａ２ａ）中、Ｒ^１は、それぞれ独立に水素原子、炭素原子数１〜１０の炭化水素基であり、Ｒ^２は、水素原子、又は炭素原子数１〜１０の炭化水素基であり、ただしＲ^１及びＲ^２の少なくとも一方は炭化水素基であり、Ｒ^３は、炭素原子数１〜１０の２価の脂肪族炭化水素基であり、
式（ａ２ｂ）中、Ｒ^４は、炭素原子数１〜１０の炭化水素基であり、Ｒ^５は、水素原子、又は炭素原子数１〜１０の炭化水素基であり、Ｒ^６は炭素原子数１〜１０の２価の脂肪族炭化水素基であり、
式（ａ２ｃ）中、Ｒ^７は、それぞれ独立に炭素原子数１〜１０の炭化水素基であり、Ｒ^８は、それぞれ独立に水素原子、又は炭素原子数１〜１０の炭化水素基であり、Ｒ^９は、炭素原子数１〜１０の２価の炭化水素基であり、ｐは、０又は１であり、
式（ａ２ｄ）中、Ｒ^１０は、それぞれ独立に水素原子、炭素原子数１〜１０の炭化水素基であり、Ｒ^１１は、それぞれ独立に水素原子、又は炭素原子数１〜１０の炭化水素基であり、ただしＲ^１０及びＲ^１１の少なくとも一方は炭化水素基であり、Ｒ^１２は、それぞれ独立に炭素原子数１〜１０の２価の炭化水素基である。）
で表される化合物からなる群より選択される１種以上である。 <Second boron compound>
The second boron compound (A2) is a boron compound other than the first boron compound (A1). The second boron compound has the following formulas (a2a) to (a2d):

(In the formula (a2a), R ¹ is a hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, respectively, and R ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However ^{, at least one of R 1} and R ² is a hydrocarbon group, and R ³ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.
In the formula (a2b), R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ is a hydrocarbon group having 1 to 10 carbon atoms. It is a divalent aliphatic hydrocarbon group of 1 to 10.
In the formula (a2c), R ⁷ is an independent hydrogen group having 1 to 10 carbon atoms, and R ⁸ is an independent hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ⁹ is a divalent hydrocarbon group having 1 to 10 carbon atoms, and p is 0 or 1.
In the formula (a2d), R ¹⁰ is an independently hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, and R ¹¹ is an independently hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However ^{, at least one of R 10} and R ¹¹ is a hydrocarbon group, and R ¹² is a divalent hydrocarbon group having 1 to 10 carbon atoms independently. )
It is one or more selected from the group consisting of the compounds represented by.

A divalent aliphatic hydrocarbon group is bonded to the nitrogen atom in the BN bond, and a hydrogen atom is not bonded to the boron atom and the nitrogen atom in the BN bond at the same time. The commonality of this structure is that the formation of an inorganic compound such as boric acid due to hydrolysis can be suppressed from the second boron compound, and the non-uniformity of the film due to the increase of the inorganic compound can be suppressed, so that a homogeneous coating film can be formed. It is presumed that it is prompting.
Hereinafter, the compounds represented by the formulas (a2a) to (a2d) will be described.

(Compound represented by the formula (a2a))
In the formula (a2a), R ¹ is a hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, respectively, and R ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ³ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms. However, ^{at least one of R 1} and R ² is a hydrocarbon group.
Preferable examples of hydrocarbon groups having 1 to 10 carbon atoms as R ¹ and R ^{2 are the same as those of R 1a} . The R ^1, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group, and benzyl group are preferable. The R ^2, a hydrogen atom, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group, and benzyl group are preferable.

The aliphatic hydrocarbon group as R ³ may be linear or branched, but is preferably linear. Preferred examples of R ³ are methylene, ethane-1,2-diyl group, propane-1,3-diyl, butane-1,4-diyl group, pentane-1,5-diyl group, hexane - It is a 1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, and a decane-1,10-diyl group.
The R ^3, ethane-1,2-diyl group and propane-1,3-diyl group, is preferred.

Specific examples of the compound represented by the formula (a2a) include the following compounds.

(Compound represented by the formula (a2b))
In the formula (a2b), R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ is a hydrocarbon group having 1 to 10 carbon atoms. It is a divalent aliphatic hydrocarbon group of 1 to 10.
Preferable examples of hydrocarbon groups having 1 to 10 carbon atoms as R ⁴ and R ^{5 are the same as those of R 1a} . The R ^4, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group, and benzyl group are preferable. The R ^5, a hydrogen atom, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group, and benzyl group are preferable.
Preferable examples of the divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms as R ^{6 are the same as those of R 3} . The R ^6, propane-1,3-diyl and butane-1,4-diyl group, is preferred.

Specific examples of the compound represented by the formula (a2a) include the following compounds.

(Compound represented by formula (a2c))
In the formula (a2c), R ⁷ is an independent hydrogen group having 1 to 10 carbon atoms, and R ⁸ is an independent hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ⁹ is a divalent hydrocarbon group having 1 to 10 carbon atoms, and p is 0 or 1. The p is preferably 1.
Preferable examples of hydrocarbon groups having 1 to 10 carbon atoms as R ⁷ and R ^{8 are the same as those of R 1a} . The R ^7, methyl group, ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group and a benzyl group, are preferred, tert- butyl group , And a benzyl group are more preferred. As R ^8, a hydrogen atom, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group, and benzyl group are preferred, methyl A group, an ethyl group, and an n-propyl group are more preferable.
Preferable examples of the divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms as R ^{9 are the same as those of R 3} . As R ⁹ , ethane-1,2-diyl group, propane-1,3-diyl group, and butane-1,4-diyl group are preferable.

Specific examples of the compound represented by the formula (a2c) include the following compounds.

(Compound represented by the formula (a2d))
In the formula (a2d), R ¹⁰ is a hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms ^{, respectively, and R 11} is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However ^{, at least one of R 10} and R ¹¹ is a hydrocarbon group, and R ¹² is a divalent hydrocarbon group having 1 to 10 carbon atoms independently.
Preferable examples of hydrocarbon groups having 1 to 10 carbon atoms as R ¹⁰ and R ^{11 are the same as those of R 1a} . The R ^10, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group and a benzyl group, are preferred, tert- butyl group , And a benzyl group are more preferred. The R ^11, a hydrogen atom, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, isobutyl group, sec- butyl group, tert- butyl group, a phenyl group, and benzyl group are preferred, methyl A group, an ethyl group, and an n-propyl group are more preferable.
Preferable examples of the divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms as R ^{12 are the same as those of R 3} . As R ¹² is preferably a methylene group and ethane-1,2-diyl group, a methylene group is more preferable.

Specific examples of the compound represented by the formula (a2d) include the following compounds.

The content of the impurity diffusion component (A) in the diffusing agent composition is not particularly limited. The content of the impurity diffusion component (A) in the diffusing agent composition is preferably 0.01 to 20% by mass, more preferably 0.05 to 15% by mass, and particularly preferably 0.1 to 10% by mass.

The ratio (mass ratio) of the content of the first boron compound (A1) to the content of the second boron compound (A2) in the diffusing agent composition is the content of the first boron compound (A1): second. The content of the boron compound (A2) is preferably 0.05: 1 to 4: 1, more preferably 0.1: 1-3: 1, and particularly preferably 0.2: 1 to 2.5: 1.
When the diffusing agent composition contains the first boron compound (A1) and the second boron compound (A2) in the above ratio, a homogeneous film having a high boron content can be formed, so that the diffusing property is good even at a low temperature. It is thought that it can be obtained.

[Hydrolyzable silane compound (B)]
The diffusing agent composition may contain a hydrolyzable silane compound (B). When the diffusing agent composition contains the hydrolyzable silane compound (B), when the diffusing agent composition is applied to the semiconductor substrate to form a thin film, the hydrolyzable silane compound is hydrolyzed and condensed in the coating film. A silicon oxide-based ultrathin film is formed on the surface. When a silicon oxide-based ultrathin film is formed in the coating film, the above-mentioned impurity diffusion component (A) is suppressed from being diffused to the outside of the substrate, and the film made of the diffusing agent composition is a thin film. However, it is easy to diffuse the impurity diffusion component (A) on the semiconductor substrate in a good and uniform manner.

The hydrolyzable silane compound (B) has a functional group that generates a hydroxyl group by hydrolysis and is bonded to a Si atom. Examples of the functional group that generates a hydroxyl group by hydrolysis include an alkoxy group, an isocyanate group, a dimethylamino group and a halogen atom. As the alkoxy group, a linear or branched aliphatic alkoxy group having 1 to 5 carbon atoms is preferable. Specific examples of suitable alkoxy groups include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group and the like. As the halogen atom, a chlorine atom, a fluorine atom, a bromine atom, and an iodine atom are preferable, and a chlorine atom is more preferable.

As the functional group that generates a hydroxyl group by hydrolysis, the isocyanate group and the number of carbon atoms 1 to 1 are considered from the viewpoints of being easily hydrolyzed and the handleability and availability of the hydrolyzable silane compound (B). The linear or branched aliphatic alkoxy group of 5 is preferable, and the methoxy group, the ethoxy group, and the isocyanate group are more preferable.

Specific examples of the hydrolyzable silane compound (B) having a linear or branched aliphatic alkoxy group having 1 to 5 carbon atoms include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetra. Isopropoxysilane, tetra-n-butoxysilane, tetra-n-pentyloxysilane, trimethoxymonoethoxysilane, dimethoxydiethoxysilane, monomethoxytriethoxysilane, trimethoxymono-n-propoxysilane, dimethoxydi-n-propoxy Orchid, monomethoxytri-n-propoxysilane, trimethoxymono-n-butoxysilane, dimethoxydi-n-butoxysilane, monomethochitri-n-tributoxysilane, trimethoxymono-n-pentyloxysilane, dimethoxydi-n-pentyl Oxysilane, monomethoxytri-n-pentyloxysilane, triethoxymono-n-propoxysilane, diethoxydi-n-propoxysilane, monoethoxytri-n-propoxysilane, triethoxymono-n-butoxysilane, diethoxydi-n -Butoxysilane, monoethoxytri-n-butoxysilane, triethoxymono-n-pentyloxysilane, diethoxydi-n-pentyloxysilane, monoethoxytri-n-pentyloxysilane, tri-n-propoxymono-n- Butoxysilane, di-n-propoxydi-n-butoxysilane, mono-n-propoxytri-n-propoxysilane, tri-n-propoxymono-n-pentyloxysilane, di-n-propoxydi-n-pentyloxysilane , Mono-n-propoxytri-n-pentyloxysilane, tri-n-butoxymono-n-pentyloxysilane, di-n-butoxydi-n-pentyloxysilane, mono-n-butoxytri-n-pentyloxysilane, Methyltrimethoxysilane, Methyltriethoxysilane, Methyltri-n-propoxysilane, Methyltri-n-propoxysilane, Methyltri-n-butoxysilane, Methyltri-n-pentyloxysilane, Ethyltrimethoxysilane, Ethyltriethoxysilane, Ethyltri Examples thereof include -n-propoxysilane, ethyltri-n-butoxysilane, and ethyltri-n-pentyloxysilane. These hydrolyzable silane compounds (B) may be used alone or in combination of two or more. Further, the partially hydrolyzed condensate of the above alkoxysilane compound can also be used as the hydrolyzable silane compound (B).

Among these, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane are preferable, and tetramethoxysilane and tetraethoxysilane are particularly preferable.

As the hydrolyzable silane compound (B) having an isocyanate group, a compound represented by the following formula (b1) is preferable.
(R ^b1 ) _4-n Si (NCO) _n ... (b1)
(In formula (b1), R ^b1 is a hydrocarbon group and n is an integer of 3 or 4.)

^{The hydrocarbon group as R b1} in the formula (b1) is not particularly limited as long as it does not impair the object of the present invention. As R ^b1 , an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 1 to 12 carbon atoms, and an aralkyl group having 1 to 12 carbon atoms are preferable.

Preferable examples of the aliphatic hydrocarbon group having 1 to 12 carbon atoms are a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group and a tert-butyl group. , N-pentyl group, isopentyl group, neopentyl group, cyclopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, cycloheptyl group, n-octyl group, cyclooctyl group, n-nonyl group, n-decyl group. , N-Undecyl group, and n-dodecyl group.

Preferable examples of aromatic hydrocarbon groups having 1 to 12 carbon atoms include phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2-ethylphenyl group and 3-ethylphenyl. Examples include a group, a 4-ethylphenyl group, an α-naphthyl group, a β-naphthyl group, and a biphenylyl group.

Preferable examples of the aralkyl group having 1 to 12 carbon atoms are a benzyl group, a phenethyl group, an α-naphthylmethyl group, a β-naphthylmethyl group, a 2-α-naphthylethyl group, and a 2-β-naphthylethyl group. Can be mentioned.

Among the hydrocarbon groups described above, a methyl group and an ethyl group are preferable, and a methyl group is more preferable.

Among the hydrolyzable silane compounds (B) represented by the formula (b1), tetraisocyanate silane, methyl triisocyanate silane, and ethyl triisocyanate silane are preferable, and tetraisocyanate silane is more preferable.

The hydrolyzable silane compound (B) having an isocyanate group and the hydrolyzable silane compound (B) having a linear or branched aliphatic alkoxy group having 1 to 5 carbon atoms may be used in combination. can. In this case, the hydrolyzable silane compound (B) having a molar number X of the hydrolyzable silane compound (B) having an isocyanate group and a linear or branched aliphatic alkoxy group having 1 to 5 carbon atoms. The ratio X / Y to the number of moles Y is preferably 1/99 to 99/1, more preferably 50/50 to 95/5, and particularly preferably 60/40 to 90/10.

When the diffusing agent composition contains the hydrolyzable silane compound (B), the content of the hydrolyzable silane compound (B) in the diffusing agent composition is not particularly limited, but the concentration of Si is 0.001 to 0.001. 3.0% by mass is preferable, and 0.01 to 1.0% by mass is more preferable. When the diffusing agent composition contains the hydrolyzable silane compound (B) at such a concentration, the external diffusion of the impurity diffusing component (A) from the thin coating film formed by using the diffusing agent composition is good. It is easy to suppress it, and it is easy to diffuse the impurity diffusion component to the semiconductor substrate in a good and uniform manner.

[Organic solvent (S)]
The diffusing agent composition usually contains an organic solvent (S) as a solvent so that a thin film coating film can be formed. The type of the organic solvent (S) is not particularly limited as long as it does not interfere with the object of the present invention.

When the diffusing agent composition contains the hydrolyzable silane compound (B), it is preferable that the diffusing agent composition does not substantially contain water. When the diffusing agent composition is substantially free of water, the diffusing agent is an amount of water in which the hydrolyzable silane compound (B) is hydrolyzed to the extent that the desired effect cannot be obtained by its addition. It means that the composition is not contained.

Specific examples of the organic solvent (S) include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether. Propropylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene Glycol monoethers such as glycol monobutyl ether, dipropylene glycol monophenyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether; diisopentyl ether ( Diisoamyl ether), dibutyl ether, diisobutyl ether, tert-butyl methyl ether, benzyl methyl ether, benzyl ethyl ether, dioxane, tetrahydrofuran, anisole, perfluoro-2-butyl tetrahydrofuran, and monoethers such as perfluorotetratetra; ethylene. Glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether , Diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dipropyl ether, and chain diethers of glycols such as dipropylene glycol dibutyl ether; cyclic diethers such as 1,4-dioxane; 1-octanone, 2-octane Tanon, 1-nonanonone, 2-nonanonone, acetone, 2-heptanone, 4-heptanone, 1-hexanone, 2-hexanone, 3-pentanone, diisobutylketone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethylketone, methylisobutylketone, ethyl Ketones such as isobutyl ketone, acetyl acetone, acetonyl acetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methylnaphthyl ketone, and isophorone; methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate , Ethethyl methoxyacetate, ethyl ethoxyacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol Monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol mono Butyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol mono Ethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl -3-Methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate , Propyl Glycoldiacetate, Methyl formate, Ethyl formate, Butyl formate, Propyl formate, Ethyl carbonate, Propyl carbonate, Butyl carbonate, Methyl pyruvate, Ethyl pyruvate, Propyl pyruvate, Butyl pyruvate, Methyl acetoacetate, Ethyl acetoacetate , Methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypro Pionate and esters such as isopropyl-3-methoxypropionate, propylene carbonate, and γ-butyrolactone; N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphos. Amido-based solvents that do not have active hydrogen atoms such as holictriamide and 1,3-dimethyl-2-imidazolidinone; sulfoxides such as dimethylsulfoxide; pentane, hexane, octane, decane, 2,2,4-trimethyl An aliphatic hydrocarbon solvent which may contain halogens such as pentane, 2,2,3-trimethylhexane, perfluorohexane, perfluoroheptane, limonene, and pinene; benzene, toluene, xylene, ethylbenzene, propylbenzene, Aromatic hydrocarbon solvents such as 1-methylpropylbenzene, 2-methylpropylbenzene, diethylbenzene, ethylmethylbenzene, trimethylbenzene, ethyldimethylbenzene, and dipropylbenzene; methanol, ethanol, n-propanol, isopropanol, butanol, Monovalent alcohols such as isobutanol, 2-methoxyethanol, 2-ethoxyethanol, 3-methyl-3-methoxybutanol, hexanol, cyclohexanol, benzyl alcohol, and 2-phenoxyethanol; ethylene glycol, propylene glycol, diethylene glycol, and Examples thereof include glycols such as dipropylene glycol. In the above-mentioned example of the preferable organic solvent (S), the organic solvent containing an ether bond and an ester bond is classified into esters. These may be used alone or in combination of two or more.

When the diffusing agent composition contains the hydrolyzable silane compound (B), the organic solvent (S) preferably has no functional group that reacts with the hydrolyzable silane compound (B). In particular, when the hydrolyzable silane compound (B) has an isocyanate group, it is preferable to use an organic solvent (S) having no functional group that reacts with the hydrolyzable silane compound (B).

The functional groups that react with the hydrolyzable silane compound (B) include both a functional group that directly reacts with a group that can generate a hydroxyl group by hydrolysis and a functional group that reacts with a hydroxyl group (silanol group) generated by hydrolysis. Is included. Examples of the functional group that reacts with the hydrolyzable silane compound (B) include a hydroxyl group, a carboxyl group, an amino group, and a halogen atom.

Preferable examples of the organic solvent having no functional group that reacts with the hydrolyzable silane compound (B) are monoethers, chain diethers, and cyclic diethers among the specific examples of the organic solvent (S) described above. , Ketones, esters, amide solvents having no active hydrogen atom, sulfoxides, aliphatic hydrocarbon solvents that may contain halogens, and organic solvents listed as specific examples of aromatic hydrocarbon solvents. Can be mentioned.

[Other ingredients]
The diffusing agent composition may contain various additives such as a surfactant, an antifoaming agent, a pH adjusting agent, and a viscosity adjusting agent as long as the object of the present invention is not impaired. Further, the diffusing agent composition may contain a binder resin for the purpose of improving the coating property and the film forming property. Various resins can be used as the binder resin, and an acrylic resin is preferable.

A diffusing agent composition can be obtained by uniformly mixing a predetermined amount of each of the above-described components.

≪Manufacturing method of semiconductor substrate≫
The manufacturing method of the semiconductor substrate is
The formation of a coating film by applying the above-mentioned diffusing agent composition and
Includes diffusion of the impurity diffusion component (A) in the diffusing agent composition onto the semiconductor substrate.
Hereinafter, the step of forming the coating film is also referred to as a “coating step”, and the step of diffusing the impurity diffusion component (A) onto the semiconductor substrate is also referred to as a “diffusion step”. Hereinafter, the coating process and the diffusion process will be described in order.

[Applying process]
In the coating step, the diffusing agent composition is applied onto the semiconductor substrate to form a coating film. Hereinafter, the coating process will be described in the order of the diffusing agent composition, the semiconductor substrate, and the coating method.

(Semiconductor substrate)
As the semiconductor substrate, various substrates conventionally used as targets for diffusing impurity diffusion components can be used without particular limitation. As the semiconductor substrate, a silicon substrate is typically used. Since the impurity diffusion component contained in the diffusing agent composition contains boron, an n-type silicon substrate is preferably used as the silicon substrate.
A semiconductor substrate such as a silicon substrate often includes a natural oxide film formed by naturally oxidizing the surface of the semiconductor substrate. For example, a silicon substrate often includes a natural oxide film _{mainly composed of SiO 2.}
When the impurity diffusion component is diffused in the semiconductor substrate, the natural oxide film on the surface of the semiconductor substrate is typically removed by using an aqueous solution of hydrofluoric acid or the like.
However, when the above-mentioned diffusing agent composition is used, the natural oxide film on the surface of the semiconductor substrate may or may not be removed.
When the natural oxide film on the surface of the semiconductor substrate is not removed, the impurity diffusion component tends to diffuse into the semiconductor substrate slightly better than when the natural oxide film is removed.
For example, when the natural oxide film on the surface of the silicon substrate is not removed, the boron atom (boron compound) is incorporated into the natural oxide film having a relatively low density of silicon, so that the boron atom (boron compound) is efficiently transferred to the surface layer of the semiconductor substrate. Boron compound) is considered to be incorporated.
As a result, it is presumed that a borosilicate glass-like thin film is formed on the surface of the semiconductor substrate, and boron is satisfactorily diffused in the semiconductor substrate.

The semiconductor substrate may have a three-dimensional structure on the surface on which the diffusing agent composition is applied. According to the present invention, even when the semiconductor substrate has such a three-dimensional structure, particularly a three-dimensional structure having a nanoscale minute pattern on its surface, the diffusing agent composition described above can be obtained, for example, at 30 nm or less. By forming a thin coating film formed by coating so as to have the same thickness as the above, the impurity diffusion component can be diffused well and uniformly on the semiconductor substrate.

The shape of the pattern is not particularly limited, but typically, a linear or curved line or groove having a rectangular cross-sectional shape, or a hole shape can be mentioned.

When the semiconductor substrate is provided with a pattern in which a plurality of parallel lines are repeatedly arranged as a three-dimensional structure, the width between the lines can be applied to a width of 1 μm or less, 100 nm or less, 60 nm or less, or 20 nm or less. .. As the height of the line, it can be applied to a height of 30 nm or more, 100 nm or more, 1 μm or more, or 5 μm or more.

(Applying method)
The film thickness of the coating film formed by using the diffusing agent composition is not particularly limited. The diffusing agent composition is applied onto the semiconductor substrate so that the film thickness of the coating film formed by using the diffusing agent composition is preferably 30 nm or less, more preferably 1 to 10 nm.
The coating film may be heated to a temperature of about 100 to 300 ° C., preferably about 150 to 250 ° C. The heating time is not particularly limited, but is, for example, about 60 to 180 seconds. By performing such heating, the stability of the film tends to be improved.
The method of applying the diffusing agent composition is not particularly limited as long as a coating film having a desired film thickness can be formed. As a method for applying the diffusing agent composition, a spin coating method, an inkjet method, and a spray method are preferable. The film thickness of the coating film is an average value of the film thicknesses of 5 points or more measured using an ellipsometer.

The film thickness of the coating film is appropriately set to an arbitrary film thickness according to the shape of the semiconductor substrate and the degree of diffusion of the impurity diffusion component (A) which is arbitrarily set.

It is also preferable to rinse the surface of the semiconductor substrate with an organic solvent while the diffusing agent composition is being applied to the surface of the semiconductor substrate. By rinsing the surface of the semiconductor substrate during the formation of the coating film, the film thickness of the coating film can be made more uniform. In particular, when the semiconductor substrate has a three-dimensional structure on its surface, the film thickness of the coating film tends to increase at the bottom (step portion) of the three-dimensional structure. However, by rinsing the surface of the semiconductor substrate after forming the coating film, the film thickness of the coating film can be made uniform.

As the organic solvent used for rinsing, the above-mentioned organic solvent which may be contained in the diffusing agent composition can be used.

[Diffusion process]
In the diffusion step, the impurity diffusion component (A) in the thin coating film formed on the semiconductor substrate is diffused on the semiconductor substrate by using the diffusing agent composition. The method of diffusing the impurity diffusing component (A) on the semiconductor substrate is not particularly limited as long as it is a method of diffusing the impurity diffusing component (A) from the coating film made of the diffusing agent composition by heating.

As a typical method, a method of heating a semiconductor substrate provided with a coating film made of a diffusing agent composition in a heating furnace such as an electric furnace can be mentioned. At this time, the heating conditions are not particularly limited as long as the impurity diffusion component (A) is diffused to a desired degree.

Usually, after the organic matter in the coating film is fired and removed in an atmosphere containing oxygen, the semiconductor substrate is heated in an atmosphere of an inert gas to diffuse the impurity diffusion component (A) into the semiconductor substrate.
The heating for firing the organic matter is preferably carried out at a temperature of preferably 300 to 1000 ° C., more preferably 400 to 800 ° C., preferably 1 second to 10 minutes, more preferably 5 seconds to 5 minutes.
The heating for diffusing the impurity diffusion component (A) is preferably at a temperature of 700 ° C. or higher and 1400 ° C. or lower, more preferably 700 ° C. or higher and lower than 1200 ° C., preferably for 1 to 120 minutes, more preferably 5 to 60 minutes. It is done for a minute.
Since the diffusing agent composition containing the above-mentioned impurity diffusing component (A) is used, the impurity diffusing component (A) is contained in the semiconductor substrate even at a low temperature such as 1000 ° C. or lower at the time of diffusion. Spreads well.
In addition, in the case of the typical composition of the present invention, since it does not contain much organic matter, heating for firing may be skipped.

Further, when the semiconductor substrate can be rapidly raised to a predetermined diffusion temperature at a temperature rise rate of 25 ° C./sec or more, the diffusion temperature holding time is 60 seconds or less, 30 seconds or less, 10 seconds or less, or It may be a very short time such as less than 1 second. In this case, the impurity diffusion component (A) is likely to be diffused at a high concentration in a shallow region on the surface of the semiconductor substrate.

According to the method described above, even when a semiconductor substrate having a three-dimensional structure having minute voids on the nanometer scale is used on its surface, the semiconductor substrate can be formed while suppressing the occurrence of defects in the semiconductor substrate. Impurity diffusion components can be diffused well and uniformly.
Therefore, the method according to the present invention can be suitably applied to the production of a multigate device having a minute three-dimensional structure. Since the method according to the present invention can suppress the occurrence of defects on the semiconductor substrate when the impurity diffusion component is diffused, it is particularly preferably applied to the manufacture of elements such as CMOS image sensors and semiconductor elements such as logic LSI devices. can.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[Comparative Examples 1 to 5]
In Comparative Examples 1 to 5, the following compounds A1 to A5 were used as the impurity diffusion component (component (A)).
A1: Trimethylborate A2: Decaborane A3: Compound of the following formula (triethylamine borane)
A4: Dibutyl vinylboronate A5: Compound of the following formula (tris (n-amyloxy) boroxine)

The components (A) of the types shown in Table 1 below were each dissolved in butyl acetate so as to have a concentration of 0.5% by mass to obtain the diffusing agent compositions of Comparative Examples 1 to 5.

The diffusing agent compositions of Comparative Examples 1 to 5 were each applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to obtain a coating film having the film thickness shown in Table 1. Formed. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used. Table 1 shows the observation results of the state of the coating film.
Regarding the diffusing agent composition of Comparative Example 4 using A4 (dibutyl vinylboronate), impurities were not diffused because the coating film was not attached on the substrate.
After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (ramp annealing device), heating was performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec to achieve the diffusion temperature and diffusion time of 1 second shown in Table 1. Diffusion processing was performed. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

As a result of the diffusion treatment of the impurity diffusion component, it was confirmed whether or not the semiconductor substrate was inverted from n-type to p-type. When it is inverted, it is evaluated as ◯, and when it is not inverted, it is evaluated as ×. In the case of inversion, the sheet resistance value was measured. The results of these evaluations are shown in Table 1.
It should be noted that the diffusion test at 1200 ° C. is performed in order, and the diffusion test at a temperature lower than the temperature initially evaluated as × is not performed.

From Comparative Examples 1 to 5, when various boron compounds are used alone as an impurity diffusing agent composition, the impurity diffusing component cannot be satisfactorily diffused at a low diffusion temperature of 1000 ° C. or lower (Comparative Examples 1 to 5). 3) It can be seen that the coating film cannot be formed (Comparative Example 4), or problems such as particle formation and clouding occur in the formed coating film (Comparative Example 1, Comparative Example 2, and Comparative Example 5). ..

[Comparative Examples 6 to 11]
In Comparative Examples 6 to 11, the following compounds A6 to A11 were used as the impurity diffusion component (component (A)).
A6: Compound of the following formula (Tetrakis (dimethylamino) diboron)
A7: Compound of the following formula (diethyl (3-pyridyl) borane)
A8: Compound of the following formula (Trispirolidinoborane)
A9: Compound of the following formula (diazaborocyclohexane)
A10: Compound of the following formula (diisopropylaminoborane)
A11: Boric acid

The components (A) of the types shown in Table 2 below were each dissolved in an organic solvent (S) so as to have a concentration of 0.5% by mass to obtain the diffusing agent compositions of Comparative Examples 1 to 5. In Comparative Examples 6 to 10, butyl acetate was used as the organic solvent (S). In Comparative Example 11, a mixed solvent of PE (propylene glycol monomethyl ether) / water was used as the organic solvent (S).

The diffusing agent compositions of Comparative Examples 6 to 11 are each applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to obtain a coating film having the film thickness shown in Table 2. Formed. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used. In Comparative Examples 6 and 9, rinsing with butyl acetate was performed during coating. Table 2 shows the observation results of the state of the coating film.
Regarding the diffusing agent composition of Comparative Example 10 using A10 (diisopropylaminoborane), impurities were not diffused because the coating film did not adhere to the substrate.
After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (lamp annealing device), heating is performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec, and the diffusion temperature (1000 ° C.) and diffusion shown in Table 2 are performed. Diffusion treatment was performed at a time of 1 second. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

In both Comparative Examples 6 to 9 and Comparative Example 11, the semiconductor substrate was inverted from n-type to p-type by the diffusion treatment at 1000 ° C. Table 2 shows the measured values of sheet resistance.

From Comparative Examples 6 to 11, when various boron compounds are used alone as an impurity diffusing agent composition, the impurity diffusing component cannot be diffused well at 1000 ° C. (Comparative Examples 6 and 7), or the coating is applied. It can be seen that the film cannot be formed (Comparative Example 10), or problems such as particle formation and fogging occur in the formed coating film (Comparative Example 6, Comparative Example 8, Comparative Example 9, and Comparative Example 11). ..

[Comparative Examples 12 to 26]
In Comparative Examples 12 to 26, the above-mentioned compounds A1, A2, A4, A5, A6, A7, A9, and A10, the following A12, A13, and A14, and A15 (tris (trimethylsilyl) borate) were added as impurities. It was used as a diffusion component (component (A)).
A12: Compound of the following formula (N, N', N "-tri-tert-butylborazine)
A13: Compound of the following formula (N, N', N "-tri-ethylborazine)
A14: Compound of the following formula (N, N'-di-tert-butyl-1,3-diazaborocyclopentane)

In addition, A2, A4, A10, A12, and A13 correspond to the first boron compound (A1) ((A1) component), and A14 corresponds to the second boron compound (A2) ((A2) component). , A1, A5, A6, A7, A9, and A15 correspond to other boron compounds (other components).

The components (A) of the types shown in Table 3 below were each dissolved in butyl acetate to the concentrations shown in Table 3 below to obtain the diffusing agent compositions of Comparative Examples 12 to 26.

The diffusing agent compositions of Comparative Examples 12 to 26 were each applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to obtain a coating film having the film thickness shown in Table 3. Formed. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used. Table 3 shows the observation results of the state of the coating film.
In the diffusing agent compositions of Comparative Example 15, Comparative Example 18, and Comparative Example 20, impurities were not diffused because the coating film was hardly attached on the substrate.
After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (lamp annealing device), heating is performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec, and the diffusion temperature (1000 ° C.) and diffusion shown in Table 3 are performed. Diffusion treatment was performed at a time of 1 second. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

In Comparative Examples 12 to 14, Comparative Example 16, Comparative Example 17, Comparative Example 19 and Comparative Examples 21 to 26, the semiconductor substrate was inverted from n-type to p-type by the diffusion treatment at 1000 ° C. The measured values of sheet resistance are shown in Table 3.

From Comparative Examples 12 to 26, when the first boron compound (A1) and the second boron compound (A2) are not used in combination as the impurity diffusion component (A), the impurity diffuses at a lower diffusion temperature of 1000 ° C. or lower. The components could not be diffused well (Comparative Example 26), or a coating film having a sufficient thickness could not be formed (Comparative Example 15, Comparative Example 18, and Comparative Example 20). Non-uniformity, adhesion of the diffusing agent composition to the silicon substrate in the form of particles, and problems such as fogging may occur (Comparative Examples 12 to 14, Comparative Examples 16 to 19, and Comparative Examples 21 to 25). I understand.

[Examples 1 to 22]
In Examples 1 to 22, the above-mentioned compounds A2, A4, A10, A13, and A14 were used as the impurity diffusion component (component (A)).
In addition, A2, A4, A10, and A13 correspond to the first boron compound (A1) ((A1) component), and A14 corresponds to the second boron compound (A2) ((A2) component).

The components (A) of the types shown in Table 4 below were each dissolved in butyl acetate to the concentrations shown in Table 4 below to obtain the diffusing agent compositions of Examples 1 to 22.

The diffusing agent compositions of Examples 1 to 22 are each applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to obtain a coating film having the film thickness shown in Table 4. Formed. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used. In the examples described as having a rinse in Table 4, rinsing with butyl acetate was performed during coating.
In any of Examples 1 to 22, there was no particular problem in the state of the formed coating film.
After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (lamp annealing device), heating is performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec, and the diffusion temperature (1000 ° C.) and diffusion shown in Table 4 are performed. Diffusion treatment was performed at a time of 1 second. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

In each of Examples 1 to 22, the semiconductor substrate was inverted from n-type to p-type by the diffusion treatment at 1000 ° C. The measured values of sheet resistance are shown in Table 4.

From Examples 1 to 22, when the first boron compound (A1) and the second boron compound (A2) are used in combination as the impurity diffusion component (A), the impurity diffusion component is used at a low diffusion temperature of 1000 ° C. or lower. It can be seen that the formed coating film is less likely to have problems such as non-uniformity of film thickness and cloudiness.
Further, the diffusing agent composition of the example was stored in the air for 3 hours or 6 hours, and then diffused into a semiconductor substrate. As a result, the value of the sheet resistance value did not change significantly between the test using the diffusing agent composition immediately after preparation and the test using the diffusing agent composition after storage for a predetermined time, and the diffusing agent composition of the example was used. The storage stability was good.

[Examples 23 to 29]
In Examples 23 to 29, the above-mentioned compounds A2, A4, and A14 were used as the impurity diffusion component (component (A)).
Note that A2 and A4 correspond to the first boron compound (A1) (component (A1)), and A14 corresponds to the second boron compound (A2) (component (A2)).

The components (A) of the types shown in Table 5 below were each dissolved in butyl acetate to the concentrations shown in Table 5 below to obtain the diffusing agent compositions of Examples 23 to 29.

The diffusing agent compositions of Examples 23 to 29 are each applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to obtain a coating film having the film thickness shown in Table 5. Formed. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used. During the coating, rinsing with diisoamyl ether was performed.
In any of Examples 23 to 29, there was no particular problem in the state of the formed coating film.
After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (lamp annealing device), heating is performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec, and the diffusion temperature (1000 ° C.) and diffusion shown in Table 5 are performed. Diffusion treatment was performed at a time of 1 second. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

In all of Examples 23 to 29, the semiconductor substrate was inverted from n-type to p-type by the diffusion treatment at 1000 ° C. The measured values of sheet resistance are shown in Table 5.

According to Example 23 and Example 24, it can be seen that there is no particular problem even if a plurality of types of the first boron compound (A1) are combined with the second boron compound.
Comparing Example 27 and Example 4, which have relatively close concentrations of the impurity diffusion component (A), rinsing with diisoamyl ether is more effective than rinsing with butyl acetate. It can be seen that the decrease in film thickness due to the above is small, and it is easy to form a coating film thick enough to be advantageous for diffusion of impurities.
Furthermore, according to Example 29, it can be seen that there is no particular problem even if the first boron compound (A1) is used in a larger amount than the second boron compound (A2).

[Examples 30 to 36]
In Examples 30 to 36, the above-mentioned compounds A4, A14, and A16 were used as the impurity diffusion component (component (A)). A16 is di-n-butyl n-propylboronic acid.
Note that A4 and A16 correspond to the first boron compound (A1) (component (A1)), and A14 corresponds to the second boron compound (A2) (component (A2)).

The components (A) of the types shown in Table 6 below were each dissolved in butyl acetate to the concentrations shown in Table 6 below to obtain the diffusing agent compositions of Examples 30 to 36.

The diffusing agent compositions of Examples 30 to 36 are each applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to obtain a coating film having the film thickness shown in Table 6. Formed. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used. The film thickness of the coating film was adjusted by adjusting the rotation speed of the spin coater. During coating, rinsing was performed using the solvents of the types shown in Table 6.
In Table 6, DBE is dibutyl ether and DIAE is diisoamyl ether.
In any of Examples 30 to 36, there was no particular problem in the state of the formed coating film.
In Examples 30 to 33, the coating film was heated at 200 ° C. for 1 minute prior to the diffusion treatment.
After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (lamp annealing device), heating is performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec, and diffusion is performed at the diffusion temperature and diffusion time shown in Table 6. Processing was performed. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

In each of Examples 30 to 36, the semiconductor substrate was inverted from n-type to p-type. The measured values of sheet resistance are shown in Table 6.

[Examples 37 to 44]
In Examples 37 to 44, the diffusing agent compositions used in Examples 35 and 36 were used.
A diffusing agent composition was applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to form a coating film. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used. During the coating, the substrate was rinsed in a rotated state using the solvents of the types shown in Table 7.
In Table 7, DBE is dibutyl ether, DIAE is diisoamyl ether, and TBME is tert-butyl methyl ether.
The film thickness of the formed coating film is shown in Table 7.
In any of Examples 37 to 44, there was no particular problem in the state of the formed coating film.

After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (lamp annealing device), heating is performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec, and under conditions of a diffusion temperature of 1000 ° C. and a diffusion time of 1 second. Diffusion treatment was performed. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

In each of Examples 37 to 44, the semiconductor substrate was inverted from n-type to p-type. The measured values of sheet resistance are shown in Table 7.

According to Table 7, from Examples 37 to 44, it can be seen that good diffusion of the impurity diffusion component is possible regardless of the type of the rinsing solvent.

[Example 45]
The diffusing agent compositions used in Examples 25 and 26 were used.
Next, a diffusing agent composition was applied to the surface of a silicon substrate (n-type) having a plurality of grooves having a width of 350 nm and a depth of 3 μm using a spin coater to form a coating film having a film thickness of 7 nm. As the silicon substrate, a substrate from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass was used.
During the coating, rinsing with diisoamyl ether was performed.

When the cross section of the semiconductor substrate after forming the coating film was observed with an electron microscope, it was found that the coating film was formed almost uniformly on the front surface of the inner surface of the recess (groove).

Next, using a rapid thermal annealing device (lamp annealing device), heating is performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 25 ° C./sec, at a diffusion temperature of 1000 ° C. and a diffusion time of 10 seconds. Diffusion treatment was performed. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

When the surface of the semiconductor substrate after the diffusion treatment was observed by scanning capacitance microscopy (SCM method) and scanning spread resistance microscopy (SSRM method) and the carrier distribution on the surface of the semiconductor substrate was confirmed, it had irregularities. It was found that the entire surface of the semiconductor substrate was p-shaped almost uniformly.

[Examples 46 to 49]
In Examples 46 to 49, the above-mentioned compounds A4, A14, and A17 were used as impurity diffusion components (component (A)). A17 is diisopropyl allylboronate.
Note that A4 and A17 correspond to the first boron compound (A1) (component (A1)), and A14 corresponds to the second boron compound (A2) (component (A2)).

The components (A) of the types shown in Table 8 below were each dissolved in butyl acetate to the concentrations shown in Table 8 below to obtain the diffusing agent compositions of Examples 46 to 49.

The diffusing agent compositions of Examples 46 to 49 are each applied to the surface of a silicon substrate (6 inches, n-type) having a flat surface using a spin coater to obtain a coating film having the film thickness shown in Table 8. Formed. As the silicon substrate, in Examples 47 and 49, a silicon substrate having a natural oxide film on its surface was used as it was. Further, in Examples 46 and 48, substrates from which the natural oxide film on the surface had been removed by immersion in an aqueous solution of hydrofluoric acid having a concentration of 0.5% by mass were used. During the coating, the substrate was rinsed in a rotated state using the solvents of the types shown in Table 8.
In Table 8, DBE is dibutyl ether and DIAE is diisoamyl ether.
In any of Examples 46 to 49, there was no particular problem in the state of the formed coating film.
After forming the coating film, the impurity diffusion component was diffused according to the following method.
Using a rapid thermal annealing device (lamp annealing device), heating was performed under a nitrogen atmosphere with a flow rate of 1 L / m at a heating rate of 15 ° C./sec, and the diffusion temperature and diffusion time 25 seconds shown in Table 8 were obtained. Diffusion processing was performed. The starting point of the diffusion time is when the temperature of the substrate reaches a predetermined diffusion temperature. After the diffusion was complete, the semiconductor substrate was rapidly cooled to room temperature.

In each of Examples 46 to 49, the semiconductor substrate was inverted from n-type to p-type by the diffusion treatment under the conditions shown in Table 8. The measured values of sheet resistance are shown in Table 8.

From Examples 46 to 49, it can be seen that the impurity diffusion component is satisfactorily diffused on the silicon substrate regardless of whether or not the natural oxide film on the surface of the silicon substrate is removed.
Further, from the comparison between Examples 46 and 47 and the comparison between Examples 48 and 49, when the natural oxide film on the surface of the silicon substrate is not removed, compared with the case where the natural oxide film is removed, It can be seen that the impurity diffusion component is easily diffused well.

Claims (8)

A diffusing agent composition used for diffusing impurities into a semiconductor substrate.
Contains the impurity diffusion component (A)
The impurity diffusion component (A) contains a first boron compound (A1) and a second boron compound (A2).
The first boron compound (A1) is produced by boron hydride or hydrolysis.
The following equation (a1e) and equation (a1f):
B (R ^1a ) ₂ OH ... (a1e)
B (R ^1a ) (OH) ₂ ... (a1f)
(In the formula (A1e), and ^{(A1f), R 1a} is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
A boron compound capable of producing one or more compounds selected from the group consisting of the compounds represented by.
The second boron compound (A2) is a boron compound other than the first boron compound (A1), and the following formulas (a2a) to (a2d):

(In the formula (a2a), R ¹ is a hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, respectively, and R ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However ^{, at least one of R 1} and R ² is a hydrocarbon group, and R ³ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.
In the formula (a2b), R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ is a hydrocarbon group having 1 to 10 carbon atoms. It is a divalent aliphatic hydrocarbon group of 1 to 10.
In the formula (a2c), R ⁷ is an independent hydrogen group having 1 to 10 carbon atoms, and R ⁸ is an independent hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R ⁹ is a divalent hydrocarbon group having 1 to 10 carbon atoms, and p is 0 or 1.
In the formula (a2d), R ¹⁰ is an independently hydrogen atom and a hydrocarbon group having 1 to 10 carbon atoms, and R ¹¹ is an independently hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, respectively. However ^{, at least one of R 10} and R ¹¹ is a hydrocarbon group, and R ¹² is a divalent hydrocarbon group having 1 to 10 carbon atoms independently. )
A diffusing agent composition which is at least one selected from the group consisting of compounds represented by. The first boron compound (A1) is a boron hydride having 2 to 10 boron atoms, and the following formulas (a1a) to (a1d):
B (R ¹³ ) _q (OR ¹⁴ ) _(3-q) ... (a1a)

(In the formula (a1a), R ¹³ and R ¹⁴ are each independently a hydrocarbon group having 1 to 10 carbon atoms, and q is an integer of 1 or 2.
Wherein ^{(a1b), R 15} are each independently a hydrocarbon group having 1 to 10 carbon atoms,
In formula (a1c), R ¹⁶ and R ¹⁷ are each independently a hydrocarbon group having 1 to 10 carbon atoms, and r is 1 or 2.
In the formula (a1d), R ¹⁸ and R ¹⁹ are independently hydrogen atoms or hydrocarbons having 1 to 10 carbon atoms. )
The diffuser composition according to claim 1, which is one or more selected from the group consisting of the compound represented by. The diffusing agent composition according to claim 1 or 2, which comprises an organic solvent (S). Formation of a coating film by coating the diffusing agent composition according to any one of claims 1 to 3 on a semiconductor substrate.
A method for producing a semiconductor substrate, which comprises diffusing the impurity diffusion component (A) in the diffuser composition onto the semiconductor substrate. The method for manufacturing a semiconductor substrate according to claim 4, wherein the coating film is heated at a temperature of 700 ° C. or higher and lower than 1200 ° C. to diffuse the impurity diffusion component (A) onto the semiconductor substrate. The method for manufacturing a semiconductor substrate according to claim 4 or 5, wherein the coating film has a film thickness of 30 nm or less. The method for manufacturing a semiconductor substrate according to any one of claims 4 to 6, wherein the semiconductor substrate has a three-dimensional structure including convex portions and concave portions on a surface on which the diffusing agent composition is applied. The method for manufacturing a semiconductor substrate according to any one of claims 4 to 7, which comprises rinsing the coating film with an organic solvent.