JP2007234871A - Method and precursor solution for formation of interlayer insulating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming an interlayer insulating film which suppresses the hinderance of a polymerization reaction and has an excellent mechanical strength and a low permittivity, and to provide a precursor solution which is used in the method. <P>SOLUTION: A solution containing an adamantane derivative (10a) having an aldehyde group and an aromatic amine derivative (10b) is coated on a substrate, and thereafter the substrate is subjected to heat treatment in an atmosphere containing oxygen to form an interlayer insulating film as an organic polymer film (10d) having an adamantine skeleton and a benzoxazole skeleton. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for forming an interlayer insulating film and a precursor solution for forming an interlayer insulating film, and more specifically, a method for forming an interlayer insulating film made of a polymer material having high mechanical strength and low density. , And a precursor solution used in the formation method thereof.

Conventionally, an organic polymer film made of a polymer obtained by polymerizing aromatic molecules has been used as an interlayer insulating film for VLSI (Large Scale Integration) or the like in order to improve heat resistance. Specifically, polyimide derivatives, polyallyl ether derivatives, polyquinoline derivatives, polyparaxylene derivatives and the like are known. Since these polymers contain carbon as a main component, the polarizabilities of the constituent molecules are lower than those of SiO ₂ -based interlayer insulating films, and are attracting attention as low dielectric constant interlayer insulating films.

Specifically, the relative dielectric constant of the organic polymer mainly composed of carbon is, for example, about 2.4 to 3.0, and the dielectric constant of the SiO ₂ interlayer insulating film is about 3.3 to 4.5. Low compared to some. However, even in SiO ₂ materials, an interlayer insulating film having a relative dielectric constant of about 2.9 is known for organic SOG (Spin On Glass) into which an organic component is introduced.

For these conventional organic polymer films, the dielectric constant has been reduced because the polarizability of the organic polymer is smaller than the polarizability of SiO _2. However, in recent years, for the purpose of further reducing the relative dielectric constant. Making it porous is being studied. However, by making it porous, it is possible to significantly reduce the relative dielectric constant, while causing a decrease in adhesion and a decrease in mechanical strength. This is due to the fact that the low dielectric constant due to the porous structure is realized by reducing the cross-linking density of the organic polymer, thereby having a fundamental defect. The mechanical strength of the organic polymer film is higher as the crosslink density is higher. However, the decrease in the crosslink density due to the porous structure lowers the hardness of the material itself and also lowers the glass transition temperature. When the adhesion and mechanical strength are reduced, for example, in a multilayer wiring structure, the wiring structure is destroyed during planarization processing by chemical mechanical polishing. On the other hand, the decrease in the glass transition temperature causes the interlayer insulating film to be softened by the heat treatment after the interlayer insulating film made of the organic polymer film is formed. As a result, the multilayer wiring structure is deformed or broken.

By the way, in order to reduce the dielectric constant of an organic polymer film without causing a decrease in adhesion and a decrease in mechanical strength, a molecule having a structure having pores inside is synthesized and the molecule is polymerized. Thus, there has been proposed a method of forming an organic polymer film having a three-dimensional polymer structure containing three-dimensional pores (see, for example, Patent Document 1). For example, by forming a copolymer of a three-dimensional polymerizable monomer having four functional groups and a linear two-dimensional polymerizable monomer having two functional groups chemically bonded to the functional group A method of forming a three-dimensionally polymerized polymer structure having three-dimensional pores of molecular size is disclosed.
JP 2001-332543 A

  By the way, as a combination of a three-dimensional polymerizable monomer and a two-dimensional polymerizable monomer, a combination of an adamantane derivative having a carboxyl group and an amine derivative is known. When such a low molecular weight monomer is used, the volatilization temperature and the polymerization temperature of the two-dimensional polymerizable amine derivative monomer, which is a two-dimensional polymerizable monomer, are in substantially the same temperature range. It proceeds simultaneously with the volatilization of the dimensionally polymerizable amine derivative monomer. For this reason, since the two-dimensional polymerizable amine derivative monomer is reduced by volatilization, there is a problem that the polymerization reaction is inhibited and a high molecular weight polymer cannot be formed. As a result, there is a problem that the glass transition temperature is lowered and the mechanical strength is further lowered.

  In view of the above, an object of the present invention is to provide a method of forming an interlayer insulating film that suppresses inhibition of polymerization reaction, has excellent mechanical strength, and has a low dielectric constant, and a precursor solution used in the method. .

  In view of the above-mentioned problems, the present inventors have made extensive studies in order to achieve a low polymerization temperature. As a result, it is possible to lower the polymerization temperature by using an adamantane derivative having an aldehyde group as a monomer. I found it. The present invention has been made based on the above findings. Specifically, the first aspect of the present invention is for forming an interlayer insulating film containing an adamantane derivative having an aldehyde group and an aromatic amine derivative. An interlayer insulating film is formed by applying a precursor solution to a substrate and then performing a heat treatment in an atmosphere containing oxygen.

  According to the first aspect of the present invention, since the polymerization temperature of the monomer composed of an adamantane derivative having an aldehyde group and the monomer composed of an aromatic amine derivative is lowered, it is possible to suppress volatilization of the monomer composed of the aromatic amine derivative. it can. Therefore, since a high molecular weight polymer can be formed, an interlayer insulating film having excellent mechanical strength and a low dielectric constant can be formed.

  Further, the second aspect of the present invention is a copolymer of the adamantane derivative and the aromatic amine derivative obtained by heat-treating a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative. An interlayer insulating film is formed by applying a precursor solution for forming an interlayer insulating film containing the oligomer, and applying heat treatment in an oxygen-containing atmosphere after coating on the substrate.

  According to the second aspect of the present invention, in addition to the effects of the first aspect described above, the precursor solution for forming an interlayer insulating film containing an oligomer has a three-dimensional polymer skeleton formed in the solution state. Since film shrinkage due to heat treatment after coating can be suppressed, density reduction can be improved and an interlayer insulating film having a lower dielectric constant can be formed. In addition, by forming an oligomer in the precursor solution for forming the interlayer insulating film, the volatilization of the monomer composed of the aromatic amine derivative is suppressed even when the temperature of the heat treatment for the polymerization reaction performed after coating is increased. can do.

  According to a third aspect of the present invention, a first solution made of an adamantane derivative having an aldehyde group and a second solution containing an aromatic amine derivative are prepared separately, and then the first solution and the An interlayer insulating film is formed by applying a precursor solution for forming an interlayer insulating film prepared by mixing with the second solution onto the substrate and then performing a heat treatment in an atmosphere containing oxygen. Is.

  According to the third aspect of the present invention, in addition to the effect of the first aspect described above, the interlayer insulating film produced by mixing the first solution and the second solution immediately before coating on the substrate Since the precursor solution for formation can be used, the solution used for the polymerization reaction can be stored for a long time. In particular, depending on the type of aromatic amine derivative contained in the second solution, when the adamantane derivative having an aldehyde group is dissolved and stored in the same solution, the polymerization reaction gradually proceeds to gel at room temperature. In this case, the third aspect of the present invention is effective.

  According to the present invention, since the polymerization temperature of the monomer composed of an adamantane derivative having an aldehyde group and the monomer composed of an aromatic amine derivative is lowered, volatilization of the monomer composed of the aromatic amine derivative can be suppressed. Therefore, since a high molecular weight polymer can be formed, an interlayer insulating film having excellent mechanical strength and a low dielectric constant can be formed.

(First embodiment)
In the first embodiment of the present invention, an interlayer insulating film forming method and an interlayer insulating film forming precursor solution according to the first aspect of the present invention described above will be described.

  The precursor solution for forming an interlayer insulating film according to the first embodiment of the present invention is a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative, and the interlayer solution according to the first embodiment of the present invention. In the method of forming an insulating film, an interlayer insulating film made of an organic polymer film is formed by applying the precursor solution on a substrate and then performing a heat treatment in an atmosphere containing oxygen.

--Adamantane derivative having aldehyde group--
First, an adamantane derivative having an aldehyde group will be described.

  The adamantane derivative having an aldehyde group has the following general formula:

(However, each combination of X ₁ , X ₂ , X ₃ , and X ₄ is a combination shown in the following [Table 1], and each of R _{1 to} R ₁₂ in the following [Table 1] is hydrogen or Organic group.)
Are one type or a plurality of types.

In addition, although the types of combinations that X _{1 to} X ₄ can take are as shown in [Table 1], specifically, in the case of the combination 1a, X _{1 to} X ₄ are substituents represented by (1). In the case of the combination 1b, X _{1 to} X ₃ are the substituents shown in (1), and X ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 1c, X 1 ₁ and X ₂ are the substituents shown in (1), and X ₃ and X ₄ are hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 1d, X ₁ is shown in (1) It is a substituent, and X _{2 to} X ₄ are hydrogen, an aliphatic group or an aromatic group. Further, in the case of the combination 1e, X _{1 to} X ₄ are the substituents shown in (2), and in the case of the combination 1f, X _{1 to} X ₃ are the substituents shown in (2), and X ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 1g, X ₁ and X ₂ are the substituents shown in (2), and X ₃ and X ₄ are hydrogen, an aliphatic group or an aromatic group, in the case of combination 1h, a substituent shown in X ₁ is (2), and, X ₂ to X ₄ is hydrogen, an aliphatic group or an aromatic group.

  Here, in this embodiment, it is preferable to use an adamantane derivative having three or more aldehyde groups, for example, the combinations 1a, 1b, 1e, and 1f in [Table 1]. Since the adamantane derivative having three or more aldehyde groups is bulky, the formed interlayer insulating film has a low density and can realize a high crosslinking density.

--Aromatic amine derivatives--
Next, the aromatic amine derivative will be described.

  Aromatic amine derivatives include the following [Table 2],

(However, at least one of X _{1 to} X ₄ in [Table 2] is an NH ₂ group, and at least one of the remaining three is an OH group.)
[Table 3] below and

  The following general formula [Chemical 126]

(However, each of Y ₁ , Y ₂ , Y ₃ , and Y ₄ is a combination shown in [Table 4], [Table 5], and [Table 6] below, and [Table 4], Each of R _{1 to} R ₁₂ in [Table 5] and the following [Table 6] is hydrogen or an organic group.)
Are one type or a plurality of types.

The possible combinations of Y _{1 to} Y ₄ are as shown in [Table 4] to [Table 6]. Specifically, in [Table 4], in the case of the combination 4a, Y _{1 to} Y ₄ are substituents shown in (3), and in the case of the combination 4b, Y _{1 to} Y ₃ are substituents shown in (3), and Y ₄ is hydrogen, an aliphatic group or aromatic In the case of the combination 4c, Y ₁ and Y ₂ are the substituents shown in (3), and Y ₃ and Y ₄ are hydrogen, an aliphatic group or an aromatic group, and the combination 4d In this case, Y ₁ is the substituent shown in (3), and Y _{2 to} Y ₄ are hydrogen, an aliphatic group, or an aromatic group. In the case of the combination 4e, Y _{1 to} Y ₄ are the substituents shown in (4), and in the case of the combination 4f, Y _{1 to} Y ₃ are the substituents shown in (4), and Y ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 4g, Y ₁ and Y ₂ are substituents shown in (4), and Y ₃ and Y ₄ are hydrogen, an aliphatic group Or in the case of the combination 4h, Y < ₁ > is a substituent shown in (4), and Y < ₂ > -Y < ₄ > is hydrogen, an aliphatic group, or an aromatic group.

Further, in the case of the combination 4i, Y _{1 to} Y ₄ are substituents shown in (5), and in the case of the combination 4j, Y _{1 to} Y ₃ are substituents shown in (5), and Y ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 4k, Y ₁ and Y ₂ are the substituents shown in (5), and Y ₃ and Y ₄ are hydrogen and an aliphatic group Or in the case of the combination 4l, Y < ₁ > is a substituent shown in (5), and Y < ₂ > -Y < ₄ > is hydrogen, an aliphatic group, or an aromatic group. In the case of the combination 4m, Y _{1 to} Y ₄ are the substituents shown in (6), and in the case of the combination 4n, Y _{1 to} Y ₃ are the substituents shown in (6), and Y ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 4o, Y ₁ and Y ₂ are substituents shown in (6), and Y ₃ and Y ₄ are hydrogen and an aliphatic group. Or in the case of the combination 4p, Y < ₁ > is a substituent shown in (6), and Y < ₂ > -Y < ₄ > is hydrogen, an aliphatic group, or an aromatic group.

  The combinations 5a to 5p using the substituents (7) to (10) shown in [Table 5] and the combinations 6a to 6p using the substituents (11) to (14) shown in [Table 6]. Since the others are the same except that the substituents (3) to (6) in the combinations 4a to 4p shown in [Table 4] described above are different, the same description is omitted here.

Here, in the present embodiment, the combination of [Table 2] and Y _{1 to} Y ₄ has a hydroxyl group represented by [Chemical Formula 125] in the case of [Table 4] and [Table 5]. It is preferable to use an aromatic amine derivative. When an aromatic amine derivative having a hydroxyl group is used, the polymerization reaction does not proceed at room temperature, so that a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative can be stored for a long period of time.

In the present embodiment, it is preferable to use an aromatic amine derivative having a hydroxyl group represented by [Chemical Formula 125] in which the combination of Y _{1 to} Y ₄ is the case of [Table 4] and [Table 5]. In this case, since the volatilization temperature of the aromatic amine derivative having a hydroxyl group can be increased, it becomes possible to increase the heat treatment temperature after coating the precursor solution on the silicon wafer. Throughput can be increased. In this case, the aromatic amine derivative having a hydroxyl group is an amine derivative having a larger excluded volume. For this reason, it becomes possible to reduce the density of the cross-linked structure of the skeleton in the formed organic polymer film, and the dielectric constant can be further reduced.

  In addition, as described above, when an aromatic amine derivative having a hydroxyl group is used as the aromatic amine derivative, the above-described adamantane derivative having three or more aldehyde groups is used as the adamantane derivative having an aldehyde group. Each effect can be realized simultaneously.

  A first example embodying the first embodiment of the present invention will be described below.

-Example 1-
In Example 1, as the adamantane derivative having an aldehyde group, when the combination of X _{1 to} X ₄ is the combination 1a shown in the above [Table 1], the above [Chemical Formula 125] (provided that all of R _{1 to} R ₁₂ are all Interlayer insulation comprising an adamantane derivative <A1> represented by (when it is a hydrogen group) and diaminodihydroxybiphenyl <B1> corresponding to (2o) of [Table 2] above as an aromatic amine derivative having a hydroxyl group An example in which an interlayer insulating film is formed using a precursor solution for film formation will be described with reference to FIG.

  Interlayer insulation obtained by dissolving 300 mg of an adamantane derivative <A1> having an aldehyde group (molecular weight 553) and 234 mg of diaminodihydroxybiphenyl <B1> (molecular weight 216) as an aromatic amine derivative having a hydroxyl group in 10 ml of dimethylacetamide A precursor solution 21 for film formation was prepared in the chemical bottle 20. Next, by pressurizing the chemical solution bottle 20 with helium gas, the precursor solution 21 passes through the chemical solution nozzle 22 and passes through a filter 23 made of, for example, fluororesin (tetrafluoroethylene resin) having a thickness of 0.2 μm. 1 ml of the precursor solution 21 is dropped on a silicon wafer (semiconductor substrate) 26 having a diameter of 300 nm installed on the rotation support base 25 in the rotation 24 and rotated for 30 seconds so that the rotation speed of the silicon wafer 26 becomes 3000 rpm. The thin film 27 was formed on the silicon wafer 26 by coating.

  Next, the silicon wafer 26 on which the thin film 27 was formed was heat-treated at 120 ° C. for 100 seconds using a hot plate, thereby volatilizing the solvent from the thin film 27. Thereafter, heat treatment was further performed on a hot plate at 160 ° C. for 30 minutes in an oxygen-containing atmosphere. As a result, the polymerization reaction between the adamantane derivative <A1> having an aldehyde group and diaminodihydroxybiphenyl <B1> can proceed on the silicon wafer 26 in the thin film 27. Thereafter, heat treatment was further performed in an electric furnace at 400 ° C. for 30 minutes in a nitrogen atmosphere. As a result, an interlayer insulating film made of an organic polymer film having an adamantane skeleton and a benzoxazole skeleton was formed on the silicon wafer 26.

  When the film thickness of the interlayer insulating film was measured using a spectroscopic ellipsometer, it was 420 nm. Further, when the relative dielectric constant of the interlayer insulating film was measured using a mercury prober, a value of 2.2 was obtained.

  In this embodiment, the heat treatment in an oxygen-containing atmosphere is performed at 160 ° C., but it is preferable to perform the heat treatment in a temperature range of 100 ° C. or more and 200 ° C. or less. This is because the volatilization temperature of the monomer composed of the aromatic amine derivative is 200 ° C. or higher, so that the polymerization reaction with the monomer composed of the adamantane derivative having an aldehyde group suppresses the volatilization of the monomer composed of the aromatic amine derivative. Can do. In addition, such a temperature range is suitable as a temperature range in which the formation rate of the polybenzoxazole film on the silicon wafer 26 is practically high and the volatilization of the monomer composed of the aromatic amine derivative can be suppressed. It is.

  In addition, when an experiment was conducted on storage of a precursor solution for forming an interlayer insulating film containing an adamantane derivative having an aldehyde group and an aromatic amine derivative, 300 mg of the adamantane derivative <A1> (molecular weight 553) having the above aldehyde group and the above A solution of 234 mg of diaminodihydroxybiphenyl <B1> (molecular weight 216) dissolved in 10 ml of dimethylacetamide did not gel after standing at room temperature for 24 hours.

  Finally, a synthesis example of the organic polymer film having the above-described adamantane skeleton and benzoxazole skeleton will be described. For example, as shown in FIG. 2, an adamantane derivative (10a) having an aldehyde group and an aromatic amine derivative (10b) is polymerized to form a Schiff base (10c), and then a dehydration reaction is caused by oxidation to synthesize an organic polymer film (10d) having an adamantane skeleton and a benzoxazole skeleton.

(Second Embodiment)
In the second embodiment of the present invention, a method for forming an interlayer insulating film and a precursor solution for forming an interlayer insulating film according to the above-described second aspect of the present invention will be described.

  The precursor solution for forming an interlayer insulating film according to the second embodiment of the present invention is obtained by heat-treating a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative, and the adamantane derivative and the A solution containing an oligomer made of a copolymer with an aromatic amine derivative, and the method for forming an interlayer insulating film according to the second embodiment of the present invention comprises applying the precursor solution on a substrate, and then oxygen. An interlayer insulating film made of an organic polymer film is formed by performing a heat treatment in an atmosphere containing it.

  Here, examples of the adamantane derivative and the aromatic amine derivative having an aldehyde group are the same as those in the first embodiment described above, and thus the description thereof is omitted here.

  Further, as in the first embodiment, it is preferable to use an adamantane derivative having three or more aldehyde groups as the adamantane derivative having an aldehyde group. In addition, as in the first embodiment, it is preferable to use an aromatic amine derivative having a hydroxyl group as the aromatic amine derivative. Furthermore, it is more preferable to use an aromatic amine derivative having a hydroxyl group as the aromatic amine derivative and to use an adamantane derivative having three or more aldehyde groups as the adamantane derivative having an aldehyde group. It is the same.

-Example 2-
A second example embodying the second embodiment of the present invention will be described below.

In Example 2, as the adamantane derivative having an aldehyde group, when the combination of X _{1 to} X _{4 is} the combination (1a) shown in the above [Table 1], the above [Chemical Formula 125] (however, R _{1 to} R ₁₂ And a diaminodihydroxybiphenyl <B1> corresponding to (2o) of [Table 2] above as an aromatic amine derivative having a hydroxyl group. An example in which an interlayer insulating film is formed using a precursor solution for forming an interlayer insulating film will be described with reference to FIG.

   A solution is prepared by dissolving 300 mg of an adamantane derivative <A1> having an aldehyde group (molecular weight 553) and 234 mg of diaminodihydroxybiphenyl <B1> (molecular weight 216) as an aromatic amine derivative having a hydroxyl group in 10 ml of dimethylacetamide. After that, the solution was stirred at 160 ° C. for 6 hours to form an oligomer which is a copolymer of an adamantane derivative having an aldehyde group and an aromatic amine derivative having a hydroxyl group. A precursor solution 21 for forming an interlayer insulating film containing the oligomer was prepared in the chemical solution bottle 20. Next, by pressurizing the chemical solution bottle 20 with helium gas, the precursor solution 21 passes through the chemical solution nozzle 22 and passes through a filter 23 made of, for example, fluororesin (tetrafluoroethylene resin) having a thickness of 0.2 μm. 1 ml of the precursor solution 21 is dropped on a silicon wafer (semiconductor substrate) 26 having a diameter of 300 nm installed on the rotation support base 25 in the rotation 24 and rotated for 30 seconds so that the rotation speed of the silicon wafer 26 becomes 3000 rpm. The thin film 27 was formed on the silicon wafer 26 by coating.

  Next, the silicon wafer 26 on which the thin film 27 was formed was heat-treated at 120 ° C. for 100 seconds using a hot plate, thereby volatilizing the solvent from the thin film 27. Thereafter, heat treatment was further performed on a hot plate at 160 ° C. for 30 minutes in an oxygen-containing atmosphere. Thereby, the polymerization reaction of the adamantane derivative <A1> having an aldehyde group and diaminodihydroxybiphenyl <B1> can be advanced in the thin film 27 on the silicon wafer 26. Thereafter, heat treatment was further performed in an electric furnace at 400 ° C. for 30 minutes in a nitrogen atmosphere. As a result, an interlayer insulating film made of an organic polymer film having an adamantane skeleton and a benzoxazole skeleton was formed on the silicon wafer 26.

  When the film thickness of the interlayer insulating film was measured using a spectroscopic ellipsometer, it was 330 nm. Further, when the relative dielectric constant of the interlayer insulating film was measured using a mercury prober, a value of 2.0 was obtained.

  As described above, in this embodiment, since the oligomer is formed in the precursor solution for forming the interlayer insulating film, the three-dimensional polymer skeleton is formed in the solution state, so that the film shrinkage due to the heat treatment after coating is suppressed. Therefore, the density can be reduced and an interlayer insulating film having a lower dielectric constant can be formed. In addition, by forming an oligomer in the precursor solution for forming the interlayer insulating film, the volatilization of the monomer composed of the aromatic amine derivative is suppressed even when the temperature of the heat treatment for the polymerization reaction performed after coating is increased. can do. In addition, although the molecular weight of an oligomer is not specifically limited, It is desirable that it is the molecular weight which is about 10000 or more and about 100,000, and does not produce gelling.

  In this embodiment, the heat treatment in an oxygen-containing atmosphere is performed at 160 ° C., but it is preferable to perform the heat treatment in a temperature range of 100 ° C. or more and 400 ° C. or less. Such a temperature range is a suitable temperature range in which the formation rate of the polybenzoxazole film on the silicon wafer 26 is practically high and the volatilization of the monomer composed of the aromatic amine derivative can be suppressed. It is. In addition, the upper limit of the temperature range is higher than that of the first embodiment, as described above, by using a precursor solution for forming an interlayer insulating film containing an oligomer, heat treatment for a polymerization reaction performed after coating. This is because the volatilization of the monomer composed of the aromatic amine derivative can be suppressed even when the temperature of is increased.

  In addition, an interlayer insulating film containing an oligomer made of a copolymer of an adamantane derivative having an aldehyde group and an aromatic amine derivative obtained by heat-treating a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative An experiment was conducted on the storage of the precursor solution. 300 mg of the adamantane derivative <A1> (molecular weight 553) having the above aldehyde group and 234 mg of the above diaminodihydroxybiphenyl <B1> (molecular weight 216) were dissolved in 10 ml of dimethylacetamide, followed by heat treatment at 160 ° C. for 6 hours. The latter solution did not gel after standing at room temperature for 24 hours.

  Note that the synthesis example of the organic polymer film having the adamantane skeleton and the benzoxazole skeleton described above is the same as that described with reference to FIG. 2 in the first embodiment.

(Third embodiment)
In the third embodiment of the present invention, an interlayer insulating film forming method and an interlayer insulating film forming precursor solution according to the above-described third aspect of the present invention will be described.

  The precursor solution for forming an interlayer insulating film according to the third embodiment of the present invention includes a first solution made of an adamantane derivative having an aldehyde group and a second solution containing an aromatic amine derivative, which are separately produced. In the method for forming an interlayer insulating film according to the first embodiment of the present invention, the first solution and the second solution are mixed before being applied onto the substrate. The precursor solution is prepared, and the precursor solution is applied onto the substrate, and then heat treatment is performed in an atmosphere containing oxygen to form an interlayer insulating film made of an organic polymer film.

  Here, examples of the adamantane derivative having an aldehyde group are the same as those in the first embodiment described above. Further, as in the first embodiment, it is preferable to use an adamantane derivative having three or more aldehyde groups as the adamantane derivative having an aldehyde group.

  Next, the aromatic amine derivative used in this embodiment will be described.

Aromatic amine derivatives are represented by the general formulas shown in [Table 2], [Table 3], and [Chemical 126] above (provided that each of Y ₁ , Y ₂ , Y ₃ , and Y ₄ represents the following [Table 6], and each of R _{1 to} R ₁₂ in [Table 6] below is hydrogen or an organic group.)
Are one type or a plurality of types.

The possible combinations of Y _{1 to} Y ₄ are as shown in [Table 6]. Specifically, in [Table 6], in the case of the combination 6a, Y _{1 to} Y ₄ are ( 11), in the case of the combination 6b, Y _{1 to} Y ₃ are the substituents shown in (11), and Y ₄ is hydrogen, an aliphatic group, or an aromatic group. in the case of 6c, a substituent shown in Y ₁ and Y ₂ (11), and, Y ₃ and Y ₄ are hydrogen, an aliphatic group or an aromatic group, in the case of combination. 6d, Y ₁ Is a substituent represented by (11), and Y _{2 to} Y ₄ are hydrogen, an aliphatic group or an aromatic group. In the case of the combination 6e, Y _{1 to} Y ₄ are the substituents shown in (12), and in the case of the combination 6f, Y _{1 to} Y ₃ are the substituents shown in (12), and Y ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 6g, Y ₁ and Y ₂ are substituents shown in (12), and Y ₃ and Y ₄ are hydrogen, an aliphatic group Or in the case of the combination 6h, Y < ₁ > is a substituent shown in (12), and Y < ₂ > -Y < ₄ > is hydrogen, an aliphatic group, or an aromatic group.

Further, in the case of the combination 6i, Y _{1 to} Y ₄ are the substituents shown in (13), and in the case of the combination 6j, Y _{1 to} Y ₃ are the substituents shown in (13), and Y ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 6k, Y ₁ and Y ₂ are the substituents shown in (13), and Y ₃ and Y ₄ are hydrogen and an aliphatic group or an aromatic group, in the case of combination 6l, a substituent shown in Y ₁ is (13), and, Y ₂ to Y ₄ is hydrogen, an aliphatic group or an aromatic group. In the case of the combination 6m, Y _{1 to} Y ₄ are the substituents shown in (14), and in the case of the combination 6n, Y _{1 to} Y ₃ are the substituents shown in (14), and Y ₄ is hydrogen, an aliphatic group or an aromatic group, and in the case of the combination 6o, Y ₁ and Y ₂ are the substituents shown in (14), and Y ₃ and Y ₄ are hydrogen and an aliphatic group Or in the case of the combination 6p, Y < ₁ > is a substituent shown in (14), and Y < ₂ > -Y < ₄ > is hydrogen, an aliphatic group, or an aromatic group.

In the third embodiment, as the aromatic amine derivative, [Table 3] and an aromatic amine derivative represented by [Chemical 126] in which the combination of Y _{1 to} Y ₄ is [Table 6] are used. It is particularly effective when. In this case, when dissolved in the same solution as the monomer composed of an adamantane derivative having an aldehyde group, the polymerization reaction proceeds gradually even at room temperature and gels. Therefore, the first solution and the second solution are combined. After preparing separately, the first solution and the second solution are mixed just before coating on the substrate to prepare a precursor solution for forming an interlayer insulating film, thereby suppressing the gelation of the precursor solution Thus, an interlayer insulating film made of an organic polymer film can be formed.

In the present embodiment, it is preferable to use an aromatic amine derivative represented by [Chemical 126] in which the combination of Y _{1 to} Y ₄ is [Table 6]. In this case, since the volatilization temperature of the aromatic amine derivative can be increased, the heat treatment temperature after the precursor solution is applied on the silicon wafer can be increased, so that the throughput of the film formation can be increased. It becomes possible. In this case, the aromatic amine derivative is an amine derivative having a larger excluded volume. For this reason, it becomes possible to reduce the density of the cross-linked structure of the skeleton in the formed organic polymer film, and the dielectric constant can be further reduced.

-Example 3-
A third example embodying the third embodiment of the present invention will be described below.

In Example 3, as the adamantane derivative having an aldehyde group, the above-mentioned [Chemical Formula 125] (provided that R _{1 to} R ₁₂ ) when the combination of X _{1 to} X _{4 is} the combination (1a) shown in [Table 1] above. And a diaminobenzidine <B2> which is a case shown in (3o) of [Table 3] above as a first solution containing an adamantane derivative <A1> represented by (when all are hydrogen groups) and an aromatic amine derivative An example in which an interlayer insulating film is formed using a precursor solution for forming an interlayer insulating film formed by mixing a second solution containing, will be described with reference to FIG.

  A first solution 31 prepared by dissolving 300 mg of an adamantane derivative <A1> having an aldehyde group (molecular weight 553) in 5 ml of dimethylacetamide is prepared in the first chemical bottle 30, and diaminobenzidine <B2> (molecular weight 214). A second solution 35 in which 230 mg is dissolved in 5 ml of dimethylacetamide is prepared in the second chemical solution bottle 34. Thereafter, the first solution 31 and the second solution 34 are respectively passed through the first chemical liquid nozzle 32 and the second chemical liquid nozzle 36, for example, a fluororesin (tetrafluoroethylene resin) having a thickness of 0.2 μm. A precursor for forming an interlayer insulating film formed by filtering through a first filter 33 and a second filter 37 and mixing a first solution 31 and a second solution 34 in a third chemical solution bottle 38. Solution 39 was prepared. Next, by pressurizing the chemical solution bottle 39 with helium gas, the precursor solution 39 passes through the third chemical solution nozzle 40 and is a silicon wafer (semiconductor substrate) having a diameter of 300 nm installed on the rotation support base 42 in the coater cup 41. 1 ml of the precursor solution 39 was dropped on 43, and spin coating was performed for 30 seconds so that the rotational speed of the silicon wafer 43 was 3000 rpm, whereby a thin film 44 was formed on the silicon wafer 43.

  Next, the silicon wafer 43 on which the thin film 44 was formed was heat treated on a hot plate at 120 ° C. for 100 seconds to volatilize the solvent from the thin film 44. Thereafter, heat treatment was further performed on a hot plate at 160 ° C. for 30 minutes in an oxygen-containing atmosphere. Thereby, the polymerization reaction of the adamantane derivative <A1> having an aldehyde group and the aromatic amine derivative <B2> can proceed in the thin film 44 on the silicon wafer 43. Thereafter, heat treatment was further performed in an electric furnace at 400 ° C. for 30 minutes in a nitrogen atmosphere. As a result, an interlayer insulating film made of an organic polymer film having an adamantane skeleton and a benzimidazole skeleton was formed on the silicon wafer 43. In this example, the heat treatment in an oxygen-containing atmosphere was performed at 160 ° C., but it is desirable that the heat treatment be performed in a temperature range of 100 ° C. or higher and 200 ° C. or lower, as in the first embodiment. It is.

  When the film thickness of the interlayer insulating film was measured using a spectroscopic ellipsometer, it was 500 nm. Further, when the relative dielectric constant of the interlayer insulating film was measured using a mercury prober, a value of 2.4 was obtained.

As described above, in this embodiment, the first solution and the second solution are separately prepared, and then the first solution and the second solution are mixed immediately before being applied onto the substrate, so that the interlayer insulating film is mixed. Since the precursor solution for formation is prepared, as described above, for example, [Table 3] and the aromatic represented by [Chemical 126] in which the combination of Y _{1 to} Y ₄ is [Table 6] Suppresses gelation that occurs when an amine derivative and an adamantane derivative having an aldehyde group are dissolved in the same solution, enabling the formation of an interlayer insulating film made of an organic polymer film having an adamantane skeleton and a benzimidazole skeleton To do.

  Finally, a synthesis example of the organic polymer film having the above-described adamantane skeleton and benzimidazole skeleton will be described. For example, as shown in FIG. 4, an adamantane derivative (50a) having an aldehyde group and an aromatic amine derivative (50b) is polymerized to form a Schiff base (50c), and then a dehydration reaction is caused by oxidation to synthesize an organic polymer film (50d) having an adamantane skeleton and a benzimidazole skeleton.

  The method for forming an interlayer insulating film and the precursor solution for forming the interlayer insulating film of the present invention are useful for forming an interlayer insulating film made of an organic polymer film having a high strength and a low dielectric constant.

It is a figure which shows the apparatus used for the spin coating method in the Example of the 1st Embodiment of this invention. It is a figure which shows an example of the synthetic | combination process of the organic polymer film which has an adamantane skeleton and a benzoxazole skeleton in the Example of the 1st Embodiment of this invention. It is a figure which shows the apparatus used for the spin coating method in the Example of the 3rd Embodiment of this invention. It is a figure which shows an example of the synthetic | combination process of the organic polymer film which has an adamantane frame | skeleton and a benzimidazole frame | skeleton in the Example of the 3rd Embodiment of this invention.

Explanation of symbols

20 Chemical solution bottle 21 Precursor solution for forming interlayer insulation film 22 Chemical solution nozzle 23 Filter 24 Coater cup 25 Rotating support base 26 Silicon wafer 27 Thin film 30 First chemical solution bottle 31 First solution 32 First chemical solution nozzle 33 First Filter 34 Second chemical bottle 35 Second solution 36 Second chemical nozzle 37 Second filter 38 Third chemical bottle 39 Precursor solution 40 for forming an interlayer insulating film Third chemical nozzle 41 Coater cup 42 Rotating support 43 Silicon wafer 44 Thin film

Claims (26)

Applying a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative on a substrate;
And a step of performing a heat treatment in an atmosphere containing oxygen. The step of applying the solution includes
The first solution containing the adamantane derivative having the aldehyde group and the second solution containing the aromatic amine derivative are mixed to form the solution, and then the solution is applied onto the substrate. A method of forming an interlayer insulating film characterized by the above.   The method for forming an interlayer insulating film according to claim 1, wherein the adamantane derivative has three or more aldehyde groups.   The method for forming an interlayer insulating film according to claim 1, wherein the aromatic amine derivative has a hydroxyl group. The adamantane derivative has three or more aldehyde groups,
The method for forming an interlayer insulating film according to claim 1, wherein the aromatic amine derivative has a hydroxyl group. Heat-treating a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative;
Applying the solution on a substrate after the heat treatment;
And a step of performing a heat treatment in an atmosphere containing oxygen.   The method for forming an interlayer insulating film according to claim 6, wherein the adamantane derivative has three or more aldehyde groups.   The method for forming an interlayer insulating film according to claim 6, wherein the aromatic amine derivative has a hydroxyl group. The adamantane derivative has three or more aldehyde groups,
The method for forming an interlayer insulating film according to claim 6, wherein the aromatic amine derivative has a hydroxyl group. The adamantane derivative having an aldehyde group has the following general formula:

(However, each of X ₁ , X ₂ , X ₃ , and X ₄ is a substituent represented by the following [Chemical 2], a substituent represented by the following [Chemical 3], a hydrogen atom, an aliphatic group, and an aromatic group. Any one type selected from the group consisting of:

At least one of the X _{1 to} X ₄ is a substituent shown in the above [Chemical 2] or the above [Chemical 3], and each of R _{1 to} R ₁₂ is hydrogen or an organic group. )
The method of forming an interlayer insulating film according to claim 1, 2, or 6. The adamantane derivative having three or more aldehyde groups is represented by the following general formula:

(However, each of X ₁ , X ₂ , X ₃ and X ₄ is a substituent represented by the following [Chemical 5], a substituent represented by the following [Chemical 6], a hydrogen atom, an aliphatic group, and an aromatic group. Any one type selected from the group consisting of:

Three or four of X _{1 to} X ₄ are all the substituents shown in [Chemical 5] or [Chemical 6], and each of R _{1 to} R ₁₂ is hydrogen or an organic group. . )
The method of forming an interlayer insulating film according to claim 1, 2, or 6. The amine derivative has the following general formulas [Chemical Formula 7] to [Chemical Formula 27] below, and

(However, in each of [Chemical 7] to [Chemical 27], at least one of X _{1 to} X ₄ is an NH ₂ group, and at least one of the remaining three is an OH group. .)
The following general formula

(However, each of Y ₁ , Y ₂ , Y ₃ , and Y ₄ is a group consisting of a substituent, a hydrogen atom, an aliphatic group, and an aromatic group represented by the following [Chemical 29] to [Chemical 36] below. There is one type selected from

At least one of Y _{1 to} Y ₄ is a substituent represented by [Chemical 29] to [Chemical 36], and each of R _{1 to} R ₁₂ is hydrogen or an organic group. )
7. The method for forming an interlayer insulating film according to claim 1, wherein the interlayer insulating film is represented by at least one selected from the group consisting of: The amine derivative has the following general formulas [Formula 37] to [57] below, and

The general formula of the following [Chemical Formula 58]

(However, each of Y ₁ , Y ₂ , Y ₃ , and Y ₄ is a group consisting of a substituent, a hydrogen atom, an aliphatic group, and an aromatic group represented by the following [Chemical Formula 59] to [Chemical Formula 62] below. There is one type selected from

At least one of Y _{1 to} Y ₄ is a substituent represented by [Chemical Formula 59] to [Chemical Formula 62], and each of R _{1 to} R ₁₂ is hydrogen or an organic group. )
The method for forming an interlayer insulating film according to claim 6, wherein the interlayer insulating film is represented by at least one selected from the group consisting of:   A precursor solution for forming an interlayer insulating film, comprising a solution containing an adamantane derivative having an aldehyde group and an aromatic amine derivative.   14. The solution according to claim 13, wherein the solution is formed by mixing a first solution containing the adamantane derivative having the aldehyde group and a second solution containing the aromatic amine derivative. A precursor solution for forming an interlayer insulating film.   The precursor solution for forming an interlayer insulating film according to claim 13 or 14, wherein the adamantane derivative has three or more aldehyde groups.   The precursor solution for forming an interlayer insulating film according to claim 13, wherein the aromatic amine derivative has a hydroxyl group. The adamantane derivative has three or more aldehyde groups,
The precursor solution for forming an interlayer insulating film according to claim 13 or 14, wherein the aromatic amine derivative has a hydroxyl group.   A precursor solution for forming an interlayer insulating film, comprising an oligomer made of a copolymer of an adamantane derivative having an aldehyde group and an aromatic amine derivative.   The precursor solution for forming an interlayer insulating film according to claim 18, wherein the adamantane derivative has three or more aldehyde groups.   The precursor solution for forming an interlayer insulating film according to claim 18, wherein the aromatic amine derivative has a hydroxyl group. The adamantane derivative has three or more aldehyde groups,
The precursor solution for forming an interlayer insulating film according to claim 18, wherein the aromatic amine derivative has a hydroxyl group. The adamantane derivative having an aldehyde group is represented by the following general formula:

(However, X ₁ , X ₂ , X ₃ , and X ₄ are each a substituent represented by the following [Chemical Formula 64], a substituent represented by the following [Chemical Formula 65], a hydrogen atom, an aliphatic group, and an aromatic group. Any one type selected from the group consisting of:

At least one of X _{1 to} X ₄ is a substituent shown in the above [Chemical Formula 64] or [Chemical Formula 65], and each of R _{1 to} R ₁₂ is hydrogen or an organic group. )
The precursor solution for forming an interlayer insulating film according to claim 13, 14 or 18, wherein The adamantane derivative having three or more aldehyde groups is represented by the general formula:

(However, each of X ₁ , X ₂ , X ₃ , and X ₄ is a substituent represented by the following [Chemical 67], a substituent represented by the following [Chemical 68], a hydrogen atom, an aliphatic group, and an aromatic group. Any one type selected from the group consisting of:

Wherein X ₁ to X 3 or all four of the _four is a substituent shown in the [formula 67] or the Formula 68], each of R ₁ to R ₁₂ is hydrogen or an organic group . )
The precursor solution for forming an interlayer insulating film according to claim 15, 17, 19, or 21, wherein The amine derivative is represented by the following general formulas [Chemical 69] to [Chemical 89]:

(However, in each of [Chemical 69] to [Chemical 89], at least one of X _{1 to} X ₄ is an NH ₂ group, and at least one of the remaining three is an OH group. .)
The general formula of [Chemical 90] below

(However, each of Y ₁ , Y ₂ , Y ₃ , and Y ₄ is a group consisting of a substituent, a hydrogen atom, an aliphatic group, and an aromatic group represented by the following [Chemical Formula 91] to [Chemical Formula 98] below. There is one type selected from

At least one of Y _{1 to} Y ₄ is a substituent represented by [Chemical Formula 91] to [Chemical Formula 98], and each of R _{1 to} R ₁₂ is hydrogen or an organic group. )
The precursor solution for forming an interlayer insulating film according to claim 13, 14, or 18, characterized by being represented by at least one selected from the group consisting of: The amine derivative is represented by the following general formulas [Chemical 99] to [119]:

The general formula of [Chemical Formula 120] below

(However, each of Y ₁ , Y ₂ , Y ₃ , and Y ₄ is a group consisting of a substituent, a hydrogen atom, an aliphatic group, and an aromatic group represented by the following [Chemical Formula 121] to [Chemical Formula 124] below. There is one type selected from

Wherein at least one of the Y ₁ to Y ₄ is a substituent shown in the [formula 121] - the Formula 124], each of R ₁ to R ₁₂ is a hydrogen or an organic group. )
The precursor solution for forming an interlayer insulating film according to any one of claims 18 to 21, wherein the precursor solution is represented by at least one selected from the group consisting of .

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