JP2007311732A - Low dielectric material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low dielectric material excellent as an interlayer insulating material that dispenses with the arrangement of holes. <P>SOLUTION: The low dielectric material including a polyindan derivative having a structure expressed by the formula (1) or the formula (2). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a low dielectric material. More specifically, the present invention relates to a low dielectric material made of a polyindane derivative and used as an interlayer insulating film material of a semiconductor device in the electric / electronic field.

  Low dielectric materials are widely used as materials in electrical and electronic parts in order to solve problems such as charging and resistance value increase. A low dielectric material is used for the purpose of lowering the dielectric constant of a member, and is often used for a portion that generates heat or as a thin film. For this reason, low dielectric materials are also required to improve heat resistance and strength at the same time.

In particular, low dielectric materials are useful as semiconductor interlayer insulating film materials, and materials having low dielectric constant, high heat resistance, high strength, and economy are being actively developed.
Currently, siloxane compounds are mainly used as semiconductor interlayer insulating film materials, which are the main applications of low dielectric materials. Siloxane compounds are mainly composed of silicon and oxygen. However, since the dielectric constant increases as the dipole moment of the molecule increases, a siloxane compound having many unshared electron pairs is disadvantageous. However, until now, the required value of the dielectric constant k of the low dielectric material may be relatively high, about 3 to 4, and siloxane compounds are used from the viewpoint of balance of strength and adhesion to the silicon wafer. It was.

In recent years, there has been a demand for finer semiconductor circuit width due to demand for higher performance of semiconductors, and it has become necessary to further lower the dielectric constant. At that time, since the problem of dielectric breakdown due to the strength of the entire semiconductor chip, physical stress, etc. becomes serious, it is necessary to maintain the strength as a thin film.
On the other hand, from the viewpoint of lowering the dielectric constant, the siloxane compound has shifted from an inorganic siloxane compound to an organic siloxane compound, and the technology has advanced to the introduction of controlled nanometer level vacancies. However, if the amount of introduced holes is increased in order to cope with further lowering of the dielectric constant, the material strength is lowered, and there is a limit to lowering the dielectric constant without lowering the strength.

Therefore, new materials such as organic polymers have been proposed. However, in addition to insulation, low dielectric constant, and high strength, there has been no material having high heat resistance particularly capable of withstanding the heat load applied during semiconductor manufacturing.
Further, organic / inorganic polymers such as borazine-silicon polymers exemplified in Patent Document 1 have been proposed. However, although it has a low dielectric constant, high strength, and high heat resistance, there is no process for removing the platinum catalyst necessary for polymerization, so that problems remain in terms of dielectric breakdown caused by residual platinum atoms and low stability.

Patent Document 2 discloses polyindanbisphenol and is characterized by a low dielectric constant. However, the dielectric constant k is not disclosed. This document also describes that conventional polyindane polymers are brittle and have undesirable mechanical properties.
Moreover, in patent document 3, polyindan is illustrated as an example of a low dielectric material. However, the “low dielectric material” in this document is only defined as a material having a k value lower than the dielectric constant k (k: about 4.0) of silicon dioxide. Nothing is disclosed about the structure or k value.
JP 2002-359240 A JP-T-2002-504531 Japanese translation of PCT publication No. 2002-510878

  An object of the present invention is to provide a low dielectric material having a low dielectric constant without introducing vacancies and suitable as an interlayer insulating film material.

（式中、Ｒ^１〜Ｒ^５及びＲ^８は、それぞれ水素、置換あるいは非置換の炭素数１〜２０の直鎖状脂肪族基、置換あるいは非置換の炭素数３〜２０の分岐状脂肪族基、置換あるいは非置換の炭素数５〜５０の脂環式置換基、置換あるいは非置換の炭素数６〜３０の芳香族基、フッ素含有脂肪族基又はフッ素含有芳香族基を表す。
Ｒ^６，Ｒ^７及びＲは、それぞれ置換あるいは非置換の炭素数１〜２０の直鎖状脂肪族基、置換あるいは非置換の炭素数３〜２０の分岐状脂肪族基、置換あるいは非置換の炭素数５〜５０の脂環式置換基、置換あるいは非置換の炭素数６〜３０の芳香族基、フッ素含有脂肪族基又はフッ素含有芳香族基を表す。
Ｒ^１〜Ｒ^８及びＲは同一でも、それぞれ異なっていてよい。
ｋは０〜３であり、Ｒが複数ある場合、Ｒの位置はいずれでもよく、それぞれ同一でも異なっていてもよい。
ｌ及びｍは、それぞれ０〜１１の整数であり、ｌ及びｍが１〜１０である場合、Ｒ^６及びＲ^７の位置はいずれでもよい。また、ｌ及びｍが２〜１１である場合、Ｒ^６及びＲ^７はそれぞれ同一でも異なっていてもよい。
ｎは、１０〜１０，０００の整数である。）
２．前記式（１）又は式（２）のＲが、置換又は非置換の炭素数５〜５０の脂環式置換基であって、ｋが０．０１〜３である１に記載の低誘電材料。
３．前記式（１）又は式（２）のＲが、置換又は非置換のシクロヘキシル基、アダマンチル基又はビアダマンチル基である２に記載の低誘電材料。
４．上記１〜４のいずれかに記載の低誘電材料からなる半導体用層間絶縁膜材料。
５．上記１〜４のいずれかに記載の低誘電材料を有機溶媒に溶解させた塗料。
６．上記１〜４のいずれかに記載の低誘電材料からなる薄膜。
７．上記６に記載の薄膜を有する半導体装置。
８．上記６に記載の薄膜を有する電子回路装置。 According to the present invention, the following low dielectric materials and the like are provided.
1. A low dielectric material comprising a polyindane derivative having a structure represented by the following formula (1) or formula (2).

(Wherein R ^{1 to} R ⁵ and R ⁸ are each hydrogen, a substituted or unsubstituted linear aliphatic group having 1 to 20 carbon atoms, a substituted or unsubstituted branched aliphatic group having 3 to 20 carbon atoms. Represents a group, a substituted or unsubstituted alicyclic substituent having 5 to 50 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a fluorine-containing aliphatic group, or a fluorine-containing aromatic group.
R ⁶ , R ⁷ and R are each a substituted or unsubstituted linear aliphatic group having 1 to 20 carbon atoms, a substituted or unsubstituted branched aliphatic group having 3 to 20 carbon atoms, a substituted or unsubstituted group. An alicyclic substituent having 5 to 50 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a fluorine-containing aliphatic group, or a fluorine-containing aromatic group.
R ^{1 to} R ⁸ and R may be the same or different.
k is 0 to 3, and when there are a plurality of R, the position of R may be any, and may be the same or different.
l and m are each an integer of 0 to 11, and when l and m are 1 to 10, the positions of R ⁶ and R ⁷ may be any. When l and m are 2 to 11, R ⁶ and R ⁷ may be the same or different.
n is an integer of 10 to 10,000. )
2. 2. The low dielectric material according to 1, wherein R in the formula (1) or (2) is a substituted or unsubstituted alicyclic substituent having 5 to 50 carbon atoms, and k is 0.01 to 3 .
3. 3. The low dielectric material according to 2, wherein R in the formula (1) or the formula (2) is a substituted or unsubstituted cyclohexyl group, adamantyl group or biadamantyl group.
4). 5. A semiconductor interlayer insulating film material comprising the low dielectric material according to any one of 1 to 4 above.
5). 5. A paint obtained by dissolving the low dielectric material according to any one of 1 to 4 in an organic solvent.
6). A thin film comprising the low dielectric material according to any one of 1 to 4 above.
7). 7. A semiconductor device having the thin film as described in 6 above.
8). 7. An electronic circuit device having the thin film as described in 6 above.

According to the present invention, it is possible to provide an excellent low dielectric material as an interlayer insulating film material without introducing holes.
Further, by using the low dielectric material of the present invention, the performance of a semiconductor device such as ULSI can be improved.

One of the low dielectric materials of the present invention is a polyindane derivative having a structure represented by the following formula (1).

In the formula (1), R ^{1 to} R ⁵ and R are each hydrogen, a substituted or unsubstituted linear aliphatic group having 1 to 20 carbon atoms, a substituted or unsubstituted branched fatty acid having 3 to 20 carbon atoms. Represents a group, a substituted or unsubstituted alicyclic substituent having 5 to 50 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a fluorine-containing aliphatic group, or a fluorine-containing aromatic group. R is not hydrogen. R ^{1 to} R ⁵ and R may be the same or different.

Examples of the linear aliphatic group having 1 to 20 carbon atoms represented by R ^{1 to} R ⁵ and R include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, hexyl group, n- Heptyl, octyl, nonyl, decyl, dodecyl, tetrahexadecyl, hexadecyl and octadecyl are preferred. Moreover, as R < ¹ > -R < ⁵ >, hydrogen is preferable.
In addition, when the substituent is couple | bonded with a C1-C20 linear aliphatic group, as a substituent, a phenyl group, a trifluoromethyl group, and an adamantyl group are preferable.

As the branched aliphatic group having 3 to 20 carbon atoms represented by R ^{1 to} R ⁵ and R, an isopropyl group, an isobutyl group, and a 2-ethylhexyl group are preferable.
In addition, when a substituent is bonded to a branched aliphatic group having 3 to 20 carbon atoms, the substituent is preferably a phenyl group, a trifluoromethyl group, or an adamantyl group.

Examples of the alicyclic substituent having 5 to 50 carbon atoms represented by R ^{1 to} R ⁵ and R include an alicyclic substituent having a monocyclic, bicyclic or polycyclic structure, and specifically, a cyclohexyl group. , Cyclooctyl group, cyclodecyl group, cyclododecyl group, cyclotetradecyl group, norbornyl group, adamantyl group and diamantyl group are preferable.
In addition, when a substituent has couple | bonded with a C5-C50 alicyclic substituent, as a substituent, a methyl group, an ethyl group, n-butyl group, a phenyl group, and an adamantyl group are preferable.

As the aromatic group having 6 to 30 carbon atoms represented by R ^{1 to} R ⁵ and R, a phenyl group, a biphenyl group, a naphthyl group, and an anthracenyl group are preferable.
In addition, when a substituent has couple | bonded with a C6-C30 aromatic group, as a substituent, a methyl group, an ethyl group, n-butyl group, a phenyl group, and an adamantyl group are preferable.

The fluorine-containing aliphatic group represented by R ^{1 to} R ⁵ and R is preferably a trifluoromethyl group or a pentafluoroethyl group. R ^{1 to} R ⁵ and R may be a fluorine-containing alicyclic group, and in this case, a perfluoroadamantyl group is preferable.

As the fluorine-containing aromatic group represented by R ^{1 to} R ⁵ and R, a pentafluorophenyl group, a 4-fluorophenyl group, a heptafluoronaphthyl group, and a nonafluoroanthracenyl group are preferable.

R ^{1 to} R ⁵ and R may be a substituent formed by combining the above substituents. Specific examples include 4-trifluoromethylphenyl group, 3-methyladamantyl group, 3-trifluoromethyladamantyl group, 3-phenyladamantyl group, and biadamantyl group.

  n is an integer of 10 to 10,000, preferably 10 to 1000. If n is less than 10, heat resistance and stability may be lowered, and if n exceeds 10,000, the solubility in an organic solvent may be lowered, and it may be difficult to form a desired form such as a thin film.

k is 0 to 3, and when there are a plurality of R, the position of R may be any, and may be the same or different. From the viewpoint of ease of production of the polyindane derivative, k is preferably 0, but in order to further lower the dielectric constant, k is preferably 0.01 to 3.
In the present invention, in the compound having R, a benzene ring partially or completely substituted by the substituent (R) and a benzene ring not substituted by the substituent (R) may be mixed, The number k may be less than 1. That is, one or more Rs may be bonded to the entire compound represented by the formula (1) or the formula (2), not within the repeating unit.

  As the terminal group of the polyindane derivative, isopropenyl group, 4-isopropenylphenyl group, isopropyl group, 4-isopropylphenyl group, hydroxyisopropyl group, 4- (hydroxyisopropyl) phenyl group, chloroisopropyl group, 4- (chloroisopropyl) ) Phenyl group and the like.

R ^{1 to} R ⁵ and R in the above formula (1) are particularly preferably hydrogen (excluding R), methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group or n-heptyl group. . A compound in which R ^{1 to} R ⁵ and R are an n-hexyl group, an n-decyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a pentamethylphenyl group, a pentafluorophenyl group, or a trifluoromethyl group is also preferable.
The structural formula of the preferred polyindane derivative of formula (1) is shown below.

Another form of the low dielectric material of the present invention is a polyindane derivative having a structure represented by the following formula (2).

In the formula (2), R ^{4 to} R ⁸ , R, k and n are the same as R ^{1 to} R ⁵ , R, k and n in the formula (1). However, R ⁶ and R ⁷ are not hydrogen. The terminal group is the same.
In Formula (2), l and m are each an integer of 0 to 11, and when l and m are 1 to 10, the positions of R ⁶ and R ⁷ may be any. When l and m are 2 to 11, R ⁶ and R ⁷ may be the same or different.

Preferable specific examples of the polyindane represented by the formula (2) include compounds in which k, l and m are 0. Such compounds are advantageous in terms of ease of manufacture. Further, R 4 ^{to R} 8, ^R is, n- hexyl, n- decyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, pentamethylphenyl group, compounds pentafluorophenyl group or a trifluoromethyl group .
The structural formula of the preferred polyindane derivative of the formula (2) is shown below.

  Among the polyindanes represented by the formulas (1) and (2), those in which a substituted or unsubstituted alicyclic substituent having 5 to 50 carbon atoms is bonded as R are particularly preferable. By introducing an alicyclic substituent as R, a compound having a particularly low dielectric constant can be obtained. This is because the intermolecular distance between the molecules constituting the thin film is relatively long and the intermolecular voids can be secured when entering as a pendant as compared to the case where the alicyclic substituent enters the main chain structure. Therefore, it is considered that the dielectric constant decreases because the density of electronic polarization that leads to an increase in dielectric constant decreases. Further, although all molecules have electronic polarization, it is considered that alicyclic substituents have low electronic polarization, so that it is difficult to contribute to an increase in dielectric constant when introduced as a pendant.

  In the present invention, the alicyclic substituent which is R is preferably directly bonded to the benzene ring. When bonded via an alkyl group or the like, the side chain bends at the intervening group portion, making it difficult to sufficiently separate the intermolecular distance. Also, from the viewpoint of heat resistance, it may be undesirable because it causes molecular movement due to rotation during heating.

  R is particularly preferably a substituted or unsubstituted cyclohexyl group, adamantyl group or a biadamantyl group represented by the following formula among the substituents described above.

（式中、Ｒ^１１は炭素数１〜２０の脂肪族炭化水素基であり、ビアダマンチル基の任意の位置に０．１〜１７個の範囲で結合している。）

(In the formula, R ¹¹ is an aliphatic hydrocarbon group having 1 to 20 carbon atoms and is bonded to an arbitrary position of the biadamantyl group in a range of 0.1 to 17).

  As the aliphatic hydrocarbon group having 1 to 20 carbon atoms, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, and the like are preferable. The number of substitutions is preferably 0.2 to 10, particularly preferably 0.5 to 6.

The conventional method of introducing dielectrics at the nanometer level, which is a method for reducing the dielectric constant, has a limit in reducing the dielectric constant without reducing the strength of the material. Needed to be introduced. That is, it is necessary to introduce vacancies of atomic size and increase the intermolecular free volume.
In the present invention, the dielectric constant can be lowered without introducing pores, and further, heat resistance and strength can be improved. In order to lower the dielectric constant, it is effective to lower the molecular polarizability by reducing the π electrons and hydrogen atoms of the molecule, but the low dielectric material of the present invention has an indane structure as the main chain. This is because the basic skeleton is a polymer compound constructed only from an alicyclic structure and an aromatic ring structure, and the molecular polarizability is low.

The dielectric constant k of the low dielectric material of the present invention is 2.7 or less. Preferably it is 2.6 or less, More preferably, it is 2.5 or less. Although it is not necessary to specify the lower limit value of the dielectric constant k, a practical value is about 1.5.
The dielectric constant k varies depending on the structure of the polyindane represented by the above formula (1) or (2), particularly the types of the substituents R ^{1 to} R ⁸ and R, the number and position of the substituents R. For example, when an alicyclic substituent, a fluorine-containing aliphatic group, or a fluorine-containing aromatic substituent is used, the dielectric constant is relatively low.
The dielectric constant k is a value obtained by the mercury probe method.

  Polyindanes represented by formula (1) and formula (2) are described in, for example, Makromolecular Chemistry, 193, 3083-3096 (1992), Makromol. Chem. 193, 487-500 (1992). Specifically, it is produced from a corresponding monomer (such as a diisopropenylbenzene derivative) by a cationic polymerization method using an acid catalyst. In addition, it can be produced from the corresponding monomer by a radical polymerization method using a radical initiator.

  As the acid catalyst used in these production methods, general strong acids such as sulfuric acid, trifluoroacetic acid, trifluoromethanesulfonic acid and the like are preferably used. As the radical initiator, compounds that suitably generate free radicals such as azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobismethylpropionamidine, and the like can be preferably used.

In order to introduce the above-described alicyclic substituent as R in the formula (1) or formula (2), a halide compound (R—X) of R and a starting compound in which R is not bonded are converted to a Lewis acid. It is obtained by reacting by the Friedel-Craft reaction in the presence.
As the halide of R (R—X), for example, 3-bromo-5,5′-dibutyl-1,1′-biadamantane is preferable.
As the Lewis acid, a compound having a known Lewis acidity can be used.
Specifically, aluminum chloride, aluminum bromide, aluminum fluoride, boron trifluoride, boron trichloride, boron tribromide, tris (pentafluorophenyl) boron, phosphorus pentafluoride, scandium triflate, titanium, zirconium Known compounds such as metal alkoxide compounds are exemplified.
Aluminum chloride and aluminum bromide are preferred. You may use combining these.

  The amount of Lewis acid added is preferably 0.001 equivalent to 10 equivalents relative to the halogenated alicyclic compound used. Preferably it is 0.01 equivalent-1 equivalent.

  The preferred Lewis acid type and amount to be added vary depending on the combination of aromatic compound and halogenated alicyclic compound and reaction conditions of the substrate, but from the viewpoint of reactivity and economy, aluminum chloride and / or aluminum bromide is used. 0.01 equivalent to 1 equivalent is used.

  Depending on the reaction substrate used and the reaction conditions, the reaction can be carried out with or without a solvent. In general, the solvent may be used because the concentration of the reaction substrate and the catalyst may decrease due to the solvent, and the reaction rate may decrease, or the solvent itself may participate in the reaction and decrease the selectivity of the reaction. There are many examples where it is preferable not to. However, a halogenated hydrocarbon solvent is generally used when it is preferable to use a solvent due to the form of the substrate or the like due to reaction limitations or post-treatment limitations. The halogenated hydrocarbon is preferably 1,1,2,2-tetrachloroethane.

  In carrying out the Friedel-Crafts reaction, alcohol solvents and basic organic solvents such as pyridine are not preferred because they suppress the catalytic action of Lewis acid. An aromatic solvent is not preferable because it reacts with a halogenated alicyclic compound as a reaction substrate to give a by-product.

  The reaction temperature for carrying out the Friedel-Crafts reaction is preferably −100 ° C. to 200 ° C., more preferably −78 ° C. to 100 ° C. If it is less than −78 ° C., a sufficient reaction rate may not be obtained, and if it exceeds 100 ° C., side reactions may progress and the yield of the desired compound may be reduced.

After polymerization, the polyindane derivative represented by the formula (1) and the formula (2) is polymerized and then purified by a purification method such as washing, ion exchange resin treatment, reprecipitation, recrystallization, microfiltration, and drying, for example, Fe ³⁺ , Cl ^−. It is preferable to remove ionic impurities such as Na ⁺ , Ca ²⁺ , reaction solvent, post-treatment solvent, moisture and the like. Thereby, a dielectric constant further falls and heat resistance or intensity | strength improves. Specifically, the amount of the ionic impurities mixed up to ppm order or less is removed by reprecipitation with ultrapure water, recrystallization, microfiltration after washing, and ion exchange resin treatment of an organic solvent solution such as toluene and acetone. be able to. Further, the removal of the purified solvent, moisture, etc. by vacuum drying or hot air drying can further reduce the dielectric constant and improve the heat resistance or strength.

  The low dielectric material of the present invention can be suitably used as a semiconductor interlayer insulating film material. For example, when used as an interlayer insulating film material of a ULSI multilayer wiring structure in the manufacture of a semiconductor device, heat resistance, strength, substrate adhesion, stability, etc. are required. Since it differs depending on the part, it cannot be defined unconditionally. However, when used as an interlayer insulating film material, it is generally desirable that the dielectric constant and the like are low, and the heat resistance, strength, substrate adhesion, stability, etc. are high. The low dielectric material of the present invention has these properties.

  In addition, the low dielectric material of the present invention does not require high-temperature polymerization (thermal curing) after being formed into a thin film, has a simple chemical structure, and can be manufactured from inexpensive raw materials without complicated processes. For this reason, it is economical with respect to the conventional thermosetting organic system interlayer insulation film material. Furthermore, since it is not necessary to add a catalyst or a crosslinking agent for thermosetting, these do not remain in the film and can be suitably used as an interlayer insulating film material.

The heat resistant temperature of the low dielectric material of the present invention is preferably in the range of 290 ° C. to 600 ° C. when used as an interlayer insulating film material. The heat-resistant temperature varies depending on the main chain structure, molecular weight, type of substituent, substitution position, and number of substitution of the polymer compound as the material. The heat-resistant temperature is improved by increasing the molecular weight, and the decomposition of the substituents, the generation of radicals due to heat that causes depolymerization, or an alicyclic substituent that is effective in improving stability, an aromatic group, Improving by introducing a fluorine-containing aromatic group into the substituents R ^{1 to} R ⁵ and R of the compound of formula (1) or to the substituents R ^{4 to} R ⁷ and R of the compound of formula (2). Can do.

  The heat resistance evaluation method can be performed by general thermophysical property evaluation such as a differential scanning calorimeter (DSC), a differential thermothermal weight simultaneous measurement device (TG / DTA). The shape of the evaluation sample can be selected as appropriate within the limits of the apparatus used in the evaluation method, whether it is in the form of a thin film, or a powder or a block that is a precursor thereof. In the present application, the heat-resistant temperature means a thermal decomposition start temperature.

The thin film elastic modulus of the low dielectric material of the present invention is preferably in the range of 5 to 100 gigapascal (GPa). The preferred value of the thin film elastic modulus cannot be generally defined by the type and structure of a semiconductor device or electronic circuit device using a thin film made of a low dielectric material, the part used, the thickness of the thin film, etc. From the viewpoint of damage in the manufacturing process of the multilayer structure composed of thin films, durability of the multilayer structure, and the like, the above range is preferable.
The thin film elastic modulus, which is a measure of the strength of the low dielectric material, means a value evaluated by the nanoindentation method.

  The thin film made of the low dielectric material of the present invention is inferior in adhesion to a substrate such as silicon as compared with a conventionally known material. The substrate adhesion can be evaluated by a tape test (evaluated by the number of thin films that are peeled off when the prepared thin film is scratched by a grid pattern and the tape is applied and peeled off).

Further, in the low dielectric material of the present invention, the main chain structure is composed of an aromatic structure and an alicyclic structural formula, and therefore has high chemical stability and physical stability. For this reason, the stability of a low dielectric material or a thin film is high mainly in a heating operation, an etching operation, an electrode wiring installation operation, and the like, which are performed when manufacturing a semiconductor device and an electronic circuit device.
From the above, the low dielectric material of the present invention has sufficient strength, substrate adhesion, and stability, for example, as an interlayer insulating film material of a ULSI multilayer wiring structure in semiconductor manufacturing.

The low dielectric material of the present invention can be dissolved in an organic solvent and used as a paint.
The low dielectric material of the present invention can be dissolved in a general organic solvent. Specific organic solvents include dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, DMF, NMP, DMSO, propylene glycol methyl ether acetate, ethyl lactate, cyclohexanone toluene, benzene, acetone, etc. Is mentioned.
The blending amount of the low dielectric material in the paint can be appropriately adjusted in consideration of the thickness of the thin film to be produced, the viscosity of the paint, and the like, but is generally about 0.01% by weight to 50% by weight.

  The low dielectric material of the present invention is preferably used in the form of a thin film such as an interlayer insulating film. A thin film made of the low dielectric material of the present invention can be formed by a generally known method such as a coating method such as a spin coating method or a spray coating method, or a CVD method using the above-described paint. A thin film having a thickness of 10 nm to 10 μm can be formed. The thin film made of the low dielectric material of the present invention can be suitably used as an interlayer insulating film for a semiconductor device (integrated circuit) or an electronic circuit device.

  Since the low dielectric material of the present invention has a low dielectric constant and excellent transparency, strength, stability, etc., a thin film produced from the low dielectric material of the present invention is a semiconductor device such as a CPU, DRAM, flash memory or the like. It can be used as an electronic circuit device such as a small electronic circuit device for information processing and an electronic circuit device for high-frequency communication, a member such as an image display device and an optical communication device, a surface protective film, a heat-resistant film, and the like.

Example 1
[Manufacture of polyindane derivatives (low dielectric materials)]
1,4-diisopropenylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 50 ml of dichloromethane in a 200 ml two-necked flask equipped with a reflux condenser and a dropping funnel and equipped with a magnetic stirrer as a stirring means 9.1 mmol) and stirred vigorously. 35.1 mmol of trifluoroacetic acid dissolved in 20 ml of dichloromethane was placed in the dropping funnel and quickly added into the vigorously stirred flask. During the addition of trifluoroacetic acid, the color of the reaction mixture changed to dark green. The reaction mixture was then stirred at room temperature for 3 hours. The reaction mixture was then placed in 180 milliliters of 2-propanol to complete the reaction. The precipitated polymer was filtered, redissolved in 10 milliliters of dichloromethane, reprecipitated in 180 milliliters of 2-propanol and filtered. The obtained solid was vacuum-dried at 70 ° C. to obtain 1.1 g of polyindane represented by the following formula (3).

Example 2
[Manufacture of polyindane derivatives (low dielectric materials)]
In the same manner as in Example 1 except that 9.1 mmol of 1,3-diisopropenylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 1,4-diisopropenylbenzene, the following formula (4 1.0 g of polyindane as shown in FIG.

Example 3
[Manufacture of polyindane derivatives (low dielectric materials)]
Instead of 1,4-diisopropenylbenzene, 9.1 mmol of 1,4-di (1-cyclohexylvinyl) benzene synthesized by the method described in Makromolecular Chemistry, 193, 3083-3096 (1992) was used. In the same manner as in Example 1, 1.5 g of polyindane represented by the following formula (5) was obtained.

Example 4
A dibutylbiadamantyl group was introduced onto the benzene ring of the polyindane derivative represented by the formula (3) synthesized in Example 1.
Specifically, a polyindane represented by the formula (3) (weight average molecular weight 7830, 0.16 g, 1 mmol as a unit monomer) and Tetrahedron Letters, 42,8645 (in a nitrogen atmosphere, in a 100 ml volume flask) 2001)), 3-bromo-5,5′-dibutyl-1,1′-biadamantane (0.46 g, 1 mmol) synthesized, and 1,1,2,2-tetrachloroethane were added. (15 ml) was added and stirred to obtain a homogeneous solution. The solution was cooled to 0 ° C. while stirring in an ice bath, and then anhydrous aluminum bromide (0.27 g, 1 mmol) was added under a nitrogen atmosphere and stirred for 3 hours while cooling to 0 ° C. Carried out.
Next, the reaction is stopped by adding methanol (1 ml) dropwise with cooling and stirring, and by adding methanol (50 ml), the product is precipitated as a white solid, filtered and washed with methanol. Dibutylbiadamantyl-substituted polyindane was obtained (0.27 g, yield 72%).
The structure of the obtained dibutylbiadamantyl-substituted polyindane was confirmed by ¹ H-NMR (FIG. 1). As a result, 0.42 mol of dibutylbiadamantyl groups were substituted for 1 mol of the unit monomer of polyindane represented by the formula (3).

[Performance evaluation of polymer]
About the polyindane derivative obtained in Examples 1-4, the weight average molecular weight, the thermal decomposition start temperature, the thin film elastic modulus, and the dielectric constant were evaluated by the following methods. The results are shown in Table 1.

1. Weight average molecular weight The weight average molecular weight of polyindane was determined by Gel Permeation Chromatography (GPC) measurement using polystyrene as a standard substance.
2. Thermal decomposition start temperature The thermal decomposition start temperature was measured using a differential thermothermal gravimetric simultaneous measurement apparatus (TG / DTA apparatus, manufactured by PerkinElmer). The thermal decomposition start temperature by (TG / DTA) under a nitrogen stream was measured.

3. Thin Film Elastic Modulus The thin film elastic modulus was evaluated by the nanoindentation method for polyindan thin films. The thin film elastic modulus was measured using a nanoindentation apparatus (Triboscope, Hystron).
The polyindane thin film was prepared by applying and drying on a silicon substrate by spin coating using the 1,1,2,2-tetrachloroethane solution (concentration: 10 weight percent) of polyindane obtained in the examples. did. The film thickness was 400 to 500 nm. This thin film has a uniform film thickness, and it has been found that the material of the present invention has a high film forming property.

4). Dielectric constant k
The mercury probe method was used for evaluation. For the measurement, a mercury prober (manufactured by Four Dimensions) was used.

  From the results shown in Table 1, the polyindane derivative of the present invention has high heat resistance, high film-forming property, high thin film strength, and low dielectric constant, and is preferably used as an electronic material, a low dielectric material, and an interlayer insulating film material for semiconductors. And was able to prove that it showed extremely high performance.

Comparative Example 1
Evaluation was performed in the same manner as in Examples, using polystyrene (weight average molecular weight = 12,000) manufactured by Sigma-Aldrich. The results are shown in Table 1.
From the results shown in Table 1, polystyrene has low heat resistance and thin film elastic modulus and high dielectric constant as compared with the material of the present invention. For this reason, it was proved that it is not suitable as a semiconductor interlayer insulating film material.

  The low dielectric material of the present invention can be used as an electronic material used in a semiconductor device, an electronic circuit device or the like, a semiconductor interlayer insulating film material, a transparent material, a high strength material, a heat resistant material, or the like.

2 is a ¹ H-NMR chart of a dibutylbiadamantyl-substituted polyindane derivative obtained in Example 4. FIG.

Claims (8)

A low dielectric material comprising a polyindane derivative having a structure represented by the following formula (1) or formula (2).

(Wherein R ^{1 to} R ⁵ and R ⁸ are each hydrogen, a substituted or unsubstituted linear aliphatic group having 1 to 20 carbon atoms, a substituted or unsubstituted branched aliphatic group having 3 to 20 carbon atoms. Represents a group, a substituted or unsubstituted alicyclic substituent having 5 to 50 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a fluorine-containing aliphatic group, or a fluorine-containing aromatic group.
R ⁶ , R ⁷ and R are each a substituted or unsubstituted linear aliphatic group having 1 to 20 carbon atoms, a substituted or unsubstituted branched aliphatic group having 3 to 20 carbon atoms, a substituted or unsubstituted group. An alicyclic substituent having 5 to 50 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a fluorine-containing aliphatic group, or a fluorine-containing aromatic group.
R ^{1 to} R ⁸ and R may be the same or different.
k is 0 to 3, and when there are a plurality of R, the position of R may be any, and may be the same or different.
l and m are each an integer of 0 to 11, and when l and m are 1 to 10, the positions of R ⁶ and R ⁷ may be any. When l and m are 2 to 11, R ⁶ and R ⁷ may be the same or different.
n is an integer of 10 to 10,000. )   2. The low dielectric constant according to claim 1, wherein R in the formula (1) or the formula (2) is a substituted or unsubstituted alicyclic substituent having 5 to 50 carbon atoms, and k is 0.01 to 3. material.   The low dielectric material according to claim 2, wherein R in the formula (1) or the formula (2) is a substituted or unsubstituted cyclohexyl group, adamantyl group or a biadamantyl group.   A semiconductor interlayer insulating film material comprising the low dielectric material according to claim 1.   The coating material which melt | dissolved the low dielectric material in any one of Claims 1-3 in the organic solvent.   A thin film comprising the low dielectric material according to claim 1.   A semiconductor device comprising the thin film according to claim 6.   An electronic circuit device comprising the thin film according to claim 6.

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