JP4945858B2 - Organic insulating film material and organic insulating film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is excellent in electrical characteristics, thermal characteristics, mechanical characteristics, and physical characteristics, semiconductor interlayer insulating film, protective film, multilayer circuit interlayer insulating film, flexible copper-clad cover coat, solder resist film, liquid crystal alignment The present invention relates to an organic insulating film material and an organic insulating film suitable for applications such as a film.
[0002]
[Prior art]
As materials for semiconductors, inorganic materials, organic materials, and the like are used in various portions depending on required characteristics. For example, as an interlayer insulating film for a semiconductor, an inorganic oxide film such as silicon dioxide produced by a chemical vapor deposition method is used. However, with the recent increase in speed and performance of semiconductors, the inorganic oxide film as described above has a problem that the relative dielectric constant is high. As one of the improvement means, application of organic materials is being studied.
[0003]
Examples of organic materials for semiconductor use include polyimide resins having excellent heat resistance, electrical properties, mechanical properties, and the like, and are used for solder resists, coverlays, liquid crystal alignment films, and the like. However, since polyimide resins generally have two carbonyl groups in the imide ring, there are problems in water absorption and electrical characteristics. For these problems, attempts have been made to improve water absorption and electrical characteristics by introducing fluorine or fluorine-containing groups into the organic polymer, and some have been put into practical use. In addition, there are polybenzoxazole resins that exhibit superior performance in terms of heat resistance, water absorption, and electrical characteristics compared to polyimide resins, and application to various fields has been attempted. For example, one having a structure consisting of 4,4′-diamino-3,3′-dihydroxybiphenyl and terephthalic acid, a structure consisting of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and terephthalic acid There are polybenzoxazole resins and the like.
[0004]
However, in the advanced field where further improvements in stricter heat resistance, electrical characteristics, water absorption, etc. are required, no material that satisfies all such requirements has yet been obtained. In other words, it exhibits excellent heat resistance, but electrical properties such as dielectric constant are not sufficient, and although the electrical properties are improved by introducing fluorine, corrosive gas is generated in the multilayer wiring formation process that causes a decrease in heat resistance. There is a problem that there is a possibility of In particular, when an organic material is applied as an interlayer insulating film for a semiconductor, heat resistance, mechanical properties, and water absorption comparable to those of inorganic materials are required, and further lower dielectric constant is required.
[0005]
In response to such a demand for higher performance, a method for reducing the density and reducing the relative dielectric constant by opening fine holes in the inorganic oxide film, which is an inorganic material, has been studied. On the other hand, as a technique for obtaining micropores in an organic material, a technique for heat-treating a block copolymer to produce a resin having micropores on the order of submicrometers is disclosed (US Pat. No. 5,776,990). ). However, in order to obtain a resin composition having fine pores while satisfying not only the dielectric constant but also mechanical properties, electrical properties, water absorption resistance, and heat resistance, resin, blocking technology, thermal decomposable components, etc. In fact, the combination of these is very limited, and no combination that satisfies all the characteristics has been obtained.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a heat-resistant organic insulating film material and an organic insulating film which are excellent in all of electric characteristics, thermal characteristics and physical characteristics in semiconductor applications, and particularly have a very low dielectric constant.
[0007]
[Means for Solving the Problems]
In view of the problems of such conventional organic insulating film materials, the present inventors have made extensive studies and, as a result, obtained a polybenzoxazole resin obtained by reacting a diaminophenol compound having a specific structure with a dicarboxylic acid compound. However, by synthesizing from a monomer that does not contain fluorine in the structure, has high heat resistance, and has a bulky structure, the density of the resin can be reduced without forming micropores in the resin. The inventors have found that low dielectric constant characteristics can be obtained, and have further studied and completed the present invention.
[0008]
That is, the present invention provides a polybenzo represented by the general formula (7) obtained by reacting the diaminophenol compound represented by the general formula (1) with the dicarboxylic acid compound represented by the general formula (4). An organic insulating film material comprising a polymer having an oxazole resin precursor as a main structure, and further comprising an organic insulating film obtained using the organic insulating film material, wherein An organic insulating film comprising a resin layer having a main structure of a polybenzoxazole resin represented by the general formula (8), prepared through a condensation reaction.
[0009]
[Chemical 9]
In the formula, X represents a structure which is one selected from the formula (2).
[0010]
[Chemical Formula 10]
In the formula, X ₁ represents a structure selected from the formula (3), and at least one of the hydrogen atoms on the benzene ring in these structures is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, It may be substituted with a monovalent organic group selected from the group consisting of an isobutyl group, a t-butyl group, and a phenyl group.
[0011]
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[0012]
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In formula, Y shows the structure which is one selected from Formula (5) or Formula (6).
[0013]
Embedded image
At least one of the hydrogen atoms on the structure of the formula (5) is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a phenyl group, a trimethylsilyl group, a triethylsilyl group, Substitution with a monovalent organic group selected from the group consisting of adamantyl groups.
[0014]
Embedded image
At least one of the hydrogen atoms in the structure of the formula (6) is from a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a phenyl group, a trimethylsilyl group, or a triethylsilyl group. It may be substituted with a monovalent organic group selected from the group consisting of
[0015]
Embedded image
In the formula, n represents an integer of 2 to 1000, X represents a structure selected from Formula (2), and Y represents one selected from Formula (5) or Formula (6).
[0016]
Embedded image
In the formula, n represents an integer of 2 to 1000, X represents a structure selected from Formula (2), and Y represents one selected from Formula (5) or Formula (6).
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The organic insulating film material of the present invention includes a diaminophenol compound having a bulky substituent structure as shown in the general formula (1), and a dicarboxylic acid compound having a bulky substituent structure as shown in the general formula (4). The main purpose is to lower the dielectric constant of the polymer by reacting with the polymer. In the presence of a dehydrating condensing agent such as the conventional acid chloride method, active ester method, polyphosphoric acid or dicyclohexylcarbodiimide. It can be obtained by a synthesis method or the like by a condensation reaction.
[0018]
In the present invention, the molar ratio (N / M) of the diaminophenol compound (M mol) represented by the general formula (1) and the dicarboxylic acid (N mol) represented by the general formula (4) is 0.00. It is preferable to react in the range of 5 to 0.99 to obtain a polymer having a branched structure. When the molar ratio (N / M) is larger than 0.99, the effect of lowering the dielectric constant due to the bulky substituent of the dicarboxylic acid may be lowered, and the molar ratio (N / M) is more than 0.5. If the molecular weight is too small, the molecular weight of the resulting polymer does not increase and the unreacted diaminophenol compound remains, which may cause a problem in the formation of the organic insulating film or may become a brittle organic insulating film.
[0019]
Examples of the diaminophenol compound represented by the general formula (1) used in the present invention include 2,4-diaminoresorcinol, 4,6-diaminoresorcinol, and 2,2-bis (3-amino-4-hydroxyphenyl). Propane, 2,2-bis (4-amino-3-hydroxyphenyl) propane, 3,3′-diamino-4,4′-dihydroxybiphenyl sulfone, 4,4′-diamino-3,3′-dihydroxybiphenyl sulfone 3,3′-diamino-4,4′-dihydroxybiphenyl, 4,4′-diamino-3,3′-dihydroxybiphenyl, 9,9-bis- {4-((4-amino-3-hydroxy) Phenoxy) phenyl} fluorene, 9,9-bis- {4-((3-amino-4-hydroxy) phenoxy) phenyl} fluorene, 9,9-bis- {4-((4 Amino-3-hydroxy) phenoxy-3-phenyl) phenyl} fluorene, 9,9-bis- {4-((3-amino-4-hydroxy) phenoxy-3-phenyl) phenyl} fluorene, 3,3′- Examples include diamino-4,4′-dihydroxydiphenyl ether, 4,4′-diamino-3,3′-dihydroxydiphenyl ether, but are not necessarily limited thereto. It is also possible to use a combination of these two or more diaminophenol compounds.
[0020]
Examples of the dicarboxylic acid represented by the general formula (4) used in the present invention include 4-methylisophthalic acid, 4-phenylisophthalic acid, 4-t-butylisophthalic acid, 4-trimethylsilylisophthalic acid, 4-adamantylisophthalic acid. Acid, 5-methylisophthalic acid, 5-phenylisophthalic acid, 5-t-butylisophthalic acid, 5-trimethylsilylisophthalic acid, 5-adamantylisophthalic acid, 2-methylterephthalic acid, 2-phenylterephthalic acid, 2-t -Butyl terephthalic acid, 2-trimethylsilyl terephthalic acid, 2-adamantyl terephthalic acid, 4,4'-bis (2-methyl) phenyl dicarboxylic acid, 4,4'-bis (3-methyl) phenyl dicarboxylic acid, 4,4 '-Bis (2-t-butyl) phenyldicarboxylic acid, 4,4'-bis (3-t-butyl) Phenyldicarboxylic acid, 4,4′-bis (2-trimethylsilyl) phenyldicarboxylic acid, 4,4′-bis (3-trimethylsilyl) phenyldicarboxylic acid, 4,4′-bis (2-adamantyl) phenyldicarboxylic acid, 4 , 4'-bis (3-adamantyl) phenyldicarboxylic acid, 6-methylnaphthalene-1,4-dicarboxylic acid, 6-t-butylnaphthalene-1,4-dicarboxylic acid, 6-trimethylsilylnaphthalene-1,4-dicarboxylic acid Acid, 6-adamantylnaphthalene-1,4-dicarboxylic acid, 4-methylnaphthalene-2,6-dicarboxylic acid, 4-t-butylnaphthalene-2,6-dicarboxylic acid, 4-trimethylsilylnaphthalene-2,6-dicarboxylic acid Acid, 4-adamantylnaphthalene-2,6-dicarboxylic acid, and the like. It is not something that can be done. It is also possible to use a combination of these two or more dicarboxylic acids.
[0021]
Examples of the dicarboxylic acid having a structure represented by the general formula (6) used in the present invention include 1,3-adamantanedicarboxylic acid, 2,5-dimethyladamantane-1,3-dicarboxylic acid, and 2,5. -Diphenyladamantane-1,3-dicarboxylic acid, 2,5-bis (t-butyl) adamantane-1,3-dicarboxylic acid and the like can be mentioned, but are not necessarily limited thereto. It is also possible to use a combination of these two or more dicarboxylic acids.
[0022]
As a method for producing the organic insulating film material, for example, in the acid chloride method, first, the acid chloride to be used is prepared. As an example, in the presence of a catalyst such as N, N-dimethylformamide, a dicarboxylic acid represented by the general formula (4), for example, 5-t-butylisophthalic acid and an excess amount of thionyl chloride are allowed to react at room temperature to 75 ° C. The excess thionyl chloride is distilled off by heating and reduced pressure, and the residue is recrystallized with a solvent such as hexane to obtain 5-t-butylisophthalic acid chloride.
[0023]
Next, a diaminophenol compound represented by the general formula (1), such as 2,2-bis (3-amino-4-hydroxyphenyl) propane, is usually converted into N-methyl-2-pyrrolidone, N, N- By dissolving the dicarboxylic acid chloride compound prepared in advance in a polar solvent such as dimethylacetamide in the presence of an acid acceptor such as triethylamine at room temperature to −30 ° C., the general formula (7) An organic insulating film material made of a polymer having a polybenzoxazole precursor represented as a main structure can be obtained.
[0024]
Moreover, an organic insulating film material can be obtained also by making the active ester compound of the dicarboxylic acid compound represented by General formula (4) react with a diaminophenol compound instead of the said acid chloride compound.
[0025]
In general, the organic insulating film material of the present invention is preferably dissolved in a solvent having a weight about 4 times that of the organic insulating film material and used in the form of a varnish. Solvents include N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol Monomethyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, methyl-1,3-butylene glycol acetate, 1,3-butylene glycol-3-monomethyl ether, methyl pyruvate, ethyl pyruvate, methyl-3-methoxypropio Nate, cyclohexanone, etc. can be used alone or in combination of two or more.
[0026]
In addition, the organic insulating film material of the present invention may include a surfactant, a coupling agent, or the like as various additives, if necessary, to provide an interlayer insulating film for a semiconductor, a protective film, an interlayer insulating film for a multilayer circuit, a flexible copper It can be used as a cover coat for a tension plate, a solder resist film, a liquid crystal alignment film, and the like.
[0027]
In the method for producing an insulating film of the present invention, the organic insulating film material of the present invention is dissolved in the above solvent and applied as a varnish to a suitable support such as glass, metal, silicon wafer, ceramic substrate or the like. Examples of the coating method include spin coating using a spinner, spray coating using a spray coater, dipping, printing, roll coating, and the like. Thus, after forming a coating film, it heat-processes and converts into a polybenzoxazole resin by a dehydration condensation reaction, From the resin layer which has the structure represented by General formula (8) as a main structure It is preferable to obtain an organic insulating film.
[0028]
The organic insulating film material of the present invention can be used as a photosensitive resin composition by using it together with a naphthoquinone diazide compound as a photosensitive agent.
[0029]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the content of an Example at all. For the characteristic evaluation, dielectric constant, heat resistance, and density were measured using the films prepared in Examples and Comparative Examples. The measurement conditions for each characteristic were as follows, and the measurement results are summarized in Table 1. Hereinafter, a part shows a weight part.
[0030]
1. Using a HP-4284A Precision LCR meter manufactured by Hewlett Packard, a dielectric constant was measured at a measurement frequency of 1 MHz.
[0031]
2. Using TG / DTA220 manufactured by heat resistant Seiko Instruments Inc., the temperature at which the weight loss reached 5% was measured under a nitrogen gas flow under a temperature increase rate of 10 ° C./min.
[0032]
3. A gradient solution of density water-sodium iodide is prepared at a density of 1.17 to 1.25 at 23 ° C., and measurement is performed using a density gradient type specific gravity measuring device B type manufactured by Shibayama Scientific Machinery Co., Ltd. went.
[0033]
"Example 1"
9.65 parts (10 mmol) of 9,9-bis- {4-((4-amino-3-hydroxy) phenoxy-3-phenyl) phenyl} fluorene was dried under a dry nitrogen atmosphere with 40 parts of N- Dissolved in methyl-2-pyrrolidone, to this was slowly added 2.06 parts (9.5 mmol) of 5-methylisophthalic acid dichloride at 5 ° C. over 30 minutes. Then, it returned to room temperature and stirred at room temperature for 1 hour. Thereafter, 2.45 parts (22 mmol) of triethylamine was added dropwise at 30C over 30 minutes. After completion of dropping, the mixture was returned to room temperature and reacted at room temperature for 3 hours to obtain a polybenzoxazole precursor (organic insulating film material). When the number average molecular weight (Mn) of polystyrene conversion was obtained for the obtained polybenzoxazole precursor using GPC manufactured by Tosoh Corporation, 7.0 × 10 ³ and the weight average molecular weight (Mw) was 1. It was 36 × 10 ⁴ .
[0034]
10 g of this polybenzoxazole precursor was dissolved in N-methyl-2-pyrrolidone to form a 20% solution, and filtered through a Teflon filter having a pore size of 0.2 μm to obtain a varnish. This varnish was applied onto a silicon wafer using a spin coater. After coating, after drying for 240 seconds on a 90 ° C. hot plate, using an oven in which nitrogen is introduced and the oxygen concentration is controlled to 100 ppm or less, in the order of 250 ° C./60 minutes, 350 ° C./60 minutes. It heated and converted into polybenzoxazole resin by dehydration condensation reaction, and the resin film for insulating films was obtained. Various characteristics were evaluated using the obtained film.
[0035]
"Example 2"
In Example 1, all except that 2.46 parts (9.5 mmol) of 5-t-butylisophthalic acid dichloride was used instead of 2.06 parts (9.5 mmol) of 5-methylisophthalic acid dichloride. 1, a polybenzoxazole precursor (organic insulating film material) was synthesized. When the molecular weight was measured by GPC, Mn was 7.0 × 10 ³ and Mw was 1.37 × 10 ⁴ in terms of polystyrene. Then, the varnish was prepared like Example 1, the resin film for insulating films was produced, and evaluation was performed.
[0036]
"Example 3"
Example 1 is the same as Example 1 except that 2.61 parts (9.5 mmol) of 5-trimethylsilylisophthalic acid dichloride was used instead of 2.06 parts (9.5 mmol) of 5-methylisophthalic acid dichloride. Similarly, a polybenzoxazole precursor (organic insulating film material) was synthesized. When the molecular weight was measured by GPC, Mn was 7.0 × 10 ³ and Mw was 1.37 × 10 ⁴ in terms of polystyrene. Then, the varnish was prepared like Example 1, the resin film for insulating films was produced, and evaluation was performed.
[0037]
Example 4
In Example 1, in place of 2.06 parts (9.5 mmol) of 5-methylisophthalic acid dichloride, all except that 5.20 parts (9.5 mmol) of 5-adamantylisophthalic acid dichloride were used. Similarly, a polybenzoxazole precursor (organic insulating film material) was synthesized. When the molecular weight was measured by GPC, Mn was 6.7 × 10 ³ and Mw was 1.23 × 10 ⁴ in terms of polystyrene. Then, the varnish was prepared like Example 1, the resin film for insulating films was produced, and evaluation was performed.
[0038]
"Example 5"
In Example 1, all except that 2.48 parts (9.5 mmol) of 1,3-adamantyl dicarboxylic acid were used instead of 2.06 parts (9.5 mmol) of 5-methylisophthalic acid dichloride. In the same manner as above, a polybenzoxazole precursor (organic insulating film material) was synthesized. When molecular weight was measured by GPC, Mn was 6.5 × 10 ³ and Mw was 1.12 × 10 ⁴ in terms of polystyrene. Then, the varnish was prepared like Example 1, the resin film for insulating films was produced, and evaluation was performed.
[0039]
Reference example
In a separable flask equipped with a stirrer, a nitrogen introducing tube, and a dropping funnel, 14.65 parts (40 mmol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane was dried with dimethylacetamide 200. After the addition of 7.92 parts (200 mmol) of pyridine, 16.92 g of 4,4′-hexafluoroisopropylidenebiphenyl dicarboxylic acid dichloride was added to 100 g of dimethylacetamide at −15 ° C. with introduction of dry nitrogen. 40 mmol) was added dropwise over 30 minutes, and the precipitate was collected and dried to obtain a polybenzoxazole precursor (organic insulating film material) powder. When the molecular weight was measured by GPC, Mn was 3.8 × 10 ⁴ and Mw was 8.03 × 10 ⁴ in terms of styrene. Thereafter, a varnish was prepared in the same manner as in Example 1, a resin film for an insulating film was prepared and evaluated. As a result, the dielectric constant was 2.60, the heat resistance was 505 ° C., and the density was 1.43 g / cm ^3. It was.
[0040]
“Comparative Example 1”
The same procedure as in Example 1 was conducted except that 1.93 parts (9.5 mmol) of isophthalic acid dichloride was used instead of 2.06 parts (9.5 mmol) of 5-methylisophthalic acid dichloride. A polybenzoxazole precursor (organic insulating film material) was synthesized. When the molecular weight was measured by GPC, Mn was 7.3 × 10 ³ and Mw was 1.42 × 10 ⁴ in terms of polystyrene. Then, the varnish was prepared like Example 1, the resin film for insulating films was produced, and evaluation was performed.
[0041]
"Comparative Example 2"
In Example 1, in place of 2.06 parts (9.5 mmol) of 5-methylisophthalic acid dichloride, 1.93 parts (9.5 mmol) of terephthalic acid dichloride was used in the same manner as in Example 1. A polybenzoxazole precursor (organic insulating film material) was synthesized. When the molecular weight was measured by GPC, Mn was 7.3 × 10 ³ and Mw was 1.42 × 10 ⁴ in terms of polystyrene. Then, the varnish was prepared like Example 1, the resin film for insulating films was produced, and evaluation was performed.
[0042]
[Table 1]
[0043]
As is clear from the results summarized in Table 1, all of the insulating film resin films produced using the organic insulating film material (polybenzoxazole precursor) of the present invention have a dielectric constant of 2.57 to 2. The dielectric constant was as low as .75, and a dielectric constant equivalent to that of the reference example, which was an example having a fluorine-containing group, was obtained, and the heat resistance was high. On the other hand, in the comparative example, although it is a polybenzoxazole resin, in Comparative Examples 1 and 2, since the dicarboxylic acid does not have a bulky structure, the density is higher than that of the Examples. The dielectric constant was higher than that of 2.97. On the other hand, in the reference example, the dielectric constant was as low as 2.60, but the heat resistance was low because the resin structure contained fluorine.
[0044]
【Effect of the invention】
INDUSTRIAL APPLICABILITY The present invention can provide a heat-resistant organic insulating film material and an organic insulating film having excellent electrical characteristics, thermal characteristics, mechanical characteristics, and physical characteristics, and extremely low dielectric constant. For example, it can be applied as an interlayer insulating film for semiconductors, a protective film, an interlayer insulating film for multilayer circuits, a cover coat of a flexible copper-clad plate, a solder resist film, a liquid crystal alignment film, and the like.

Claims (2)

The diaminophenol compound represented by the general formula (1) and the dicarboxylic acid compound represented by the general formula (4), 5-methylisophthalic acid, 5-trimethylsilylisophthalic acid, or 5-adamantylisophthalic acid , respectively. It is obtained by reacting one dicarboxylic acid compound with a molar ratio (N / M) of the diaminophenol compound (M mol) to the dicarboxylic acid (N mol) in the range of 0.5 to 0.99. An organic insulating film material comprising a polymer having a polybenzoxazole resin precursor represented by the general formula (7) as a main structure.
In the formula, X represents a structure which is one selected from the formula (2).
In the formula, X ₁ represents a structure selected from the formula (3), and at least one of the hydrogen atoms on the benzene ring in these structures is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, It may be substituted with a monovalent organic group selected from the group consisting of an isobutyl group, a t-butyl group, and a phenyl group.
In formula, Y is a structure represented by Formula (6).
At least one of the hydrogen atoms in the structure of the formula (6) is from a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a phenyl group, a trimethylsilyl group, or a triethylsilyl group. It may be substituted with a monovalent organic group selected from the group consisting of
In the formula, n is an integer of 2 to 1000, X is selected from Formula (2), Y is selected from Formula (6), 5-methylisophthalic acid, 5-trimethylsilylisophthalic acid, or 5-adamantylisophthalic acid. The structure which is only one is shown. (However, for 5-methylisophthalic acid, 5-trimethylsilylisophthalic acid, and 5-adamantylisophthalic acid, Y is shown as the structure excluding the corresponding carboxyl group.) An organic insulating film obtained by using the organic insulating film material according to claim 1, wherein the polybenzoxazole resin represented by the general formula (8) prepared through a dehydration condensation reaction is mainly used. An organic insulating film comprising a resin layer having a structure.
In the formula, n is an integer of 2 to 1000, X is selected from the above formula (2), Y is selected from the above formula (6), 5-methylisophthalic acid, 5-trimethylsilylisophthalic acid, or 5-adamantylisophthalic acid. The structure which is one of the above is shown. (However, for 5-methylisophthalic acid, 5-trimethylsilylisophthalic acid, and 5-adamantylisophthalic acid, Y is shown as the structure excluding the corresponding carboxyl group.)