JP4401893B2 - Polyimide precursor resin composition - Google Patents

Description

  The present invention is excellent in chemical resistance, low water absorption, adhesion, and heat resistance, which is used as an insulating material for multilayer wiring boards that can be sequentially laminated and an insulating protective film forming material for electronic components such as semiconductor chips. The present invention relates to a low-temperature curable polyimide precursor resin composition and a structure containing a polyimide resin derived from the precursor.

  Conventionally, epoxy resin has been used as an interlayer insulating resin for circuit boards. Epoxy resins are widely used for electronic materials because they are easy to handle because they have high fluidity and low processing temperature. However, they have a high coefficient of thermal expansion and are thermosetting resins, so other general thermosetting resins are used. In the same way as in the mechanical strength measurement, mechanical properties such as elongation at break and tensile strength / elongation are not sufficient, and the material is generally brittle. As a method of lowering the thermal expansion coefficient of an epoxy resin, a method of mixing a filler component having a low thermal expansion coefficient such as silica is used, but it causes a decrease in toughness and becomes a brittle material, such as tensile strength and elongation. Therefore, cracks are a problem when subjected to a reliability test as an electronic device such as a thermal shock test.

  On the other hand, polyimide resins have been widely used as substrates for electronic circuits and interlayer insulating resin layers as materials having high glass transition temperature / high chemical resistance / excellent mechanical properties / excellent electrical characteristics. However, in order to express characteristics, ordinary polyimide resins have an imidization curing temperature of 300 ° C. or higher, which is higher than thermosetting resins such as epoxy resins, which limits the range of use. It was. As a method for lowering the imidization curing temperature, a method of introducing a highly flexible structure into a polyimide molecular structure and a method of using a chemical imidizing agent such as acetic anhydride and pyridine are known. However, in the former, by introducing a highly flexible structure into the molecular chain, the glass transition temperature of polyimide has to be remarkably lowered, and the performance such as thermal expansion coefficient, heat resistance, chemical resistance and mechanical properties are impaired. There were many things. In the latter case, it is possible to lower the curing temperature for imidization, but it is difficult to control the curing rate, and it is the stage of solvent drying during storage and application to electronic circuit boards and electronic device manufacturing processes. Thus, imidization proceeds, and preferable characteristics in the production process cannot be obtained. For example, after coating a coating solution containing polyamic acid, drying a solvent at a low temperature of about 90 to 120 ° C., forming a photoresist thereon, and developing a polyamide provided in the lower layer when developing a photoresist made of an alkaline aqueous solution The method of etching holes in the acid layer at the same time, and polyimide is formed by high-temperature heating after peeling of the photoresist to obtain a holed polyimide layer has been adopted in the semiconductor chip manufacturing process etc. When a known chemical imidizing agent is used, imidization proceeds excessively at low temperature drying, so that the etching property is remarkably impaired.

In Patent Document 1, a film containing polyamic acid is heat-dried at a temperature of 80 to 200 ° C., and is semi-cured formed on a release film having a thickness of 50 μm or less and an imidization ratio of 10 to 50%. Although a technique for forming a polyamic acid film in a state is disclosed, even in this case, after the heating and drying temperature, the imidization ratio becomes 10% or more, so that the fluidity of the resin is lowered, and the composition is used as an electronic circuit wiring. There is a problem that good embedding of the resin between the wirings cannot be obtained when it is used as a laminate material for a substrate having unevenness. Patent Document 2 discloses a polyimide resin composition that can be cured at 200 ° C. or lower, but can be cured at 200 ° C. by using a chemical imidizing agent. Similarly, since the imidization ratio is 35% or more, and the fluidity of the resin is lowered, when the composition is used as a laminate material for a substrate having unevenness of electronic circuit wiring, between the wirings. There is a problem that good embedding property of the resin cannot be obtained. It has been difficult to suppress imidization at around 100 ° C. with known chemical imidizing agents.
As described above, in order to utilize the excellent physical properties of polyimide in a wider range of applications, polyimide formation does not substantially proceed in a drying process at a relatively low temperature of about 100 ° C. It has been desired to develop a material that can be completely imidized in the process of heat imidization at a low temperature.

Japanese Patent Laid-Open No. 4-339834 JP-A-8-245879

  The present invention has been made in view of the above situation, and maintains the high glass transition temperature, high chemical resistance, and excellent mechanical properties inherent to polyimide, and imidization is substantially achieved at a temperature of solvent drying. It is possible to imidize by heating at a temperature of 220 ° C. or lower, while maintaining the performance required in the manufacturing process of electronic device circuit boards and electronic elements such as resin flowability and etchability with alkaline aqueous solution. The object is to provide a composition.

As a result of intensive studies to solve the above problems, the present inventor, when using a compound having a specific structure, imidation does not proceed at a heating temperature for solvent drying, while heating at 220 ° C. or lower. The present inventors have found a polyimide precursor resin resin composition having a high latent curing property that can be completely imidized at a temperature, and have reached the present invention.
That is, the present invention is as follows.
(1) a) a polyamic acid and b) a diazabicyclo derivative represented by the following general formula (I) as essential components, and based on 100 parts by mass of the sum of the components a) and b), the component a) is 70 The low-temperature-curable polyimide resin composition, which is ˜99.9 parts by mass and the component b) is 0.1 to 30 parts by mass.

（ただし、一般式（Ｉ）中、ｍ、ｎはそれぞれ独立した整数であり、ｍ＋ｎ≦８、ｍ、ｎ≧０である。−（ＣＨ₂）−基と−（ＣＨ）−基の順序に制限は無い。Ｘは、−Ｎ（ｎ−Ｂｕ）₂、ＣＨ₃、Ｈから選ばれる少なくとも１種の基であり、Ｒは、炭素数１〜２０の有機酸残基及び／又は無機酸残基である。）
（２）上記（１）の低温硬化性ポリイミド前駆体樹脂組成物をイミド閉環させてなるポリイミド樹脂を含む構造体。

(In the general formula (I), m and n are independent integers, and m + n ≦ 8, m, and n ≧ 0. In the order of — (CH ₂ ) — group and — (CH) — group) There is no limitation, X is at least one group selected from —N (n-Bu) ₂ , CH ₃ and H, and R is an organic acid residue and / or inorganic acid residue having 1 to 20 carbon atoms. Group.)
(2) A structure containing a polyimide resin obtained by ring-closing an imide ring of the low-temperature curable polyimide precursor resin composition of (1).

According to the present invention, chemical resistance after imidization, low water absorption, adhesion, heat resistance, etc. used for insulating materials of multilayer wiring boards that can be sequentially laminated and insulating protective film forming materials in electronic parts such as semiconductor chips A polyimide precursor resin composition capable of being cured at low temperature was obtained.
In the low-temperature curable polyimide resin composition according to the present invention, imidization does not substantially proceed under heating conditions in a molding process necessary for application to an electronic circuit board or an electronic element manufacturing process, while 220 It is a polyimide resin composition that can be imidized by performing a heat treatment at a temperature of ℃ or less.
According to the present invention, not only the manufacturing process using polyamic acid in the electronic device manufacturing process such as the semiconductor manufacturing process becomes easy, but also the application of the polyamic acid to the electronic circuit board has been expanded.

Hereinafter, the present invention will be specifically described.
The polyamic acid which is component a) in the low-temperature curable polyimide resin composition of the present invention is obtained by reacting tetracarboxylic dianhydride and diamine, and if necessary, dicarboxylic acid anhydride is also added. You may make it react.
Examples of the tetracarboxylic dianhydride include pyromellitic acid, benzenetetracarboxylic acid, cyclobutanetetracarboxylic acid, cyclohexanetetracarboxylic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, oxydiphthalic acid, diphenylsulfonetetracarboxylic acid, and naphthalene. And dianhydrides such as tetracarboxylic acid. Examples of the diamine include phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, and 2,2-bis [4- (4-aminophenoxy) phenyl] propane. Furthermore, each of dicarboxylic acid anhydride, tetracarboxylic dianhydride, and diamine can be used singly or in combination of two or more.
These polyamic acids are obtained by reacting the tetracarboxylic dianhydride component and the diamine acid component, but these components may be contained in blocks or randomly.

The diazabicyclo derivative represented by the following general formula (I), which is the component b) in the low-temperature curable polyimide precursor resin composition of the present invention, is a compound composed of a diazabicyclo compound and an acid, where m and n are Each is an independent integer, and m + n ≦ 8, m, and n ≧ 0. - (CH ₂₎ - group and - (CH) - restricted to the orders of the groups no. X is at least one group selected from —N (n-Bu) ₂ , CH ₃ , and H, and R is an organic acid residue or inorganic acid residue having 1 to 20 carbon atoms.

ｍ＋ｎはジアザビシクロ誘導体の化学安定性の観点から３以上８以下が好ましい。上記ジアザビシクロ誘導体を構成するジアザビシクロ化合物としては、ジアザビシクロウンデセン、ジアザビシクロノネンがあげられる。ポリイミド樹脂との反応性の観点からジアザビシクロウンデセンが好ましい。ジアザビシクロ化合物の骨格中にジノルマルブチルアミノ基やメチル基などの置換基が導入されていてもよい。ジノルマルブチルアミノ基が導入された６−ジブチルアミノ−１、８−ジアザビシクロウンデセンなどが挙げられる。

m + n is preferably 3 or more and 8 or less from the viewpoint of chemical stability of the diazabicyclo derivative. Examples of the diazabicyclo compound constituting the diazabicyclo derivative include diazabicycloundecene and diazabicyclononene. From the viewpoint of reactivity with the polyimide resin, diazabicycloundecene is preferred. Substituents such as a di-normal butylamino group and a methyl group may be introduced into the skeleton of the diazabicyclo compound. Examples include 6-dibutylamino-1,8-diazabicycloundecene and the like into which a dinormalbutylamino group has been introduced.

Moreover, as an acid residue, R is a C1-C20 organic acid residue and / or an inorganic acid residue. Organic acid residues include aliphatic carboxylic acids such as formic acid, acetic acid and maleic acid, aromatic carboxylic acids such as succinic acid and benzoic acid, phenols such as phenol and catechol, and aromatics such as p-toluenesulfonic acid. Acid residues such as aromatic sulfonic acids, and inorganic acid residues include acid residues such as hydrochloride, sulfate, carbonate, phosphate and borate.
Due to compatibility with polyamic acid and solubility in organic solvents, acids include aliphatic carboxylic acids such as formic acid, acetic acid and maleic acid, aromatic carboxylic acids such as succinic acid and benzoic acid, and phenol and catechol. Preferred are organic acid residues such as phenols and aromatic sulfonic acids such as p-toluenesulfonic acid.

Among these, p-toluenesulfonic acid and phenol that can be easily dissociated at a temperature higher than room temperature and have good compatibility with the polyimide resin are more preferable.
In addition, the corresponding acid can be used alone or in combination of two or more with respect to the diazabicyclo derivative.
The mixing ratio of the component a) and the component b) is based on 100 parts by mass of the sum of the components a) and b), the component a) is 70 to 99.9 parts by mass, and the component b) is 0.1 to It is preferable that it is 30 mass parts, More preferably, a) component is 80-99.5 mass parts, b) A component is 0.5-20 mass parts. From the viewpoint of low-temperature curability such as curing at 220 ° C. or less, the component b) is preferably 0.1 parts by mass or more, and preferably 30 parts by mass or less from the viewpoint of controlling the curing rate of imidization.

It is also possible to add a solvent and an additive to the resin composition used in the present invention depending on the application. Examples of the solvent include those mixed with the above-described polyamic acid. Examples include γ-butyrolactone, γ-valerolactone, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl Examples include sulfoxide, 1,3-dioxane, 1,4-dioxane, cyclopentanone, cyclohexanone, diethylene glycol dimethyl ether, and tetramethylurea. Preferred solvents for use in the present invention are γ-butyrolactone, N, N-dimethylformamide and N-methyl-2-pyrrolidone. These can be used alone or in admixture of two or more. As additives, a dehydrating agent, a filler such as silica, and a surface modifier such as a silane coupling agent may be further added.
The structure made of the polyimide resin of the present invention is a structure containing a polyimide resin obtained by heat curing the polyimide precursor resin composition at a temperature of 220 ° C. or lower. The atmosphere at the time of heating may be an inert gas, or may be air as long as there are no problems such as oxidation in other components of the structure.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
In the following examples, the properties of polyamic acid and the degree of imidization were measured as follows.
(1) Reduced viscosity After adjusting the N-methyl-2-pyrrolidone solution so that the polymer concentration is 0.5 g / dl, a Ubbelohde viscometer tube with a viscosity meter number 1 manufactured by Shibata Kagaku Co., Ltd. is used, and the temperature is 30. The measurement was performed in a constant temperature water bath at ± 1 ° C.
(2) Imidization rate The imidation rate in this invention was calculated | required by IR method. The measuring instrument used was Centaurus manufactured by Thermo Nicolet Corporation, which was measured by the ATR method using a Ge crystal. Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 27,711-724 (1989), the imidation rate is determined from the ratio of the peak based on the imide ring formation near 1380 cm ^-1 to the peak based on the benzene ring near 1500 cm ^-1 . Draw a baseline as appropriate to connect the valleys of the peaks before and after those peaks, and define the height from the intersection of the line drawn from each peak to the baseline to the peak as the absorbance. the resin of the present invention the absorbance A1,1500cm ^-1 absorbance at 1380 cm ^-1 of the resin at the time of heat treatment 300 ° C. 60 min in a nitrogen atmosphere and A2, B1,1500cm ^-1 absorbance 1380 cm ^-1 in each condition Assuming that the absorbance of B2 is B2, the imidization ratio C in each condition was calculated by the following formula, assuming that it was 100 at 60 ° C. for 60 minutes.
Imidization rate C = [(B1 / B2) / (A1 / A2)] × 100 (%)

(3) Water absorption rate If imidization is not completed and polyamic acid remains, the water absorption rate of the polymer layer increases according to the amount. The water absorption was measured with a film in which the resin composition was heat-treated in air at 200 ° C. for 90 minutes, and the length was 5 cm × width 5 cm × thickness 10 μm. The film was heated and dried at 105 ° C. for 60 minutes, and then the mass was measured. Thereafter, the film was immersed in boiling water at 100 ° C. for 1 hour, and then water droplets on the film surface were wiped off and the mass was measured. The water absorption was calculated by the following formula.
Water absorption (%) = [(mass after soaking−mass before soaking) / mass before soaking] × 100
(4) Resin fluidity The fluidity of the resin composition is determined by cutting the resin composition layer formed on the polyester film into 10 cm square sheets and pressing them at a pressure of 2.9 MPa at 170 ° C. for 10 minutes. Evaluation was based on the mass% of the resin that flowed out. It was evaluated that there was sufficient resin fluidity when it was 7.0% by mass or more.

[Example 1]
A silica gel drying tube for absorbing water was attached to a 500 ml glass separable three-necked flask equipped with a stainless steel vertical stirrer. In this flask, 347.9 g of N-methyl-2-pyrrolidone (dehydrated) (manufactured by Wako Pure Chemical Industries, Ltd.) (hereinafter abbreviated as “NMP”), 4,4′-diaminodiphenyl ether (manufactured by Wakayama Seika Kogyo Co., Ltd.) After adding 27.5 g (hereinafter abbreviated as “ODA”) at room temperature, stirring and dissolving, the flask was cooled with ice water. When the temperature of the liquid in the flask reached 5 ° C., 0.5 g of phthalic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) (hereinafter abbreviated as “PA”) was added, and after stirring for 5 minutes, 3, 3 ′, 4 4,4′-benzophenonetetracarboxylic dianhydride (manufactured by Daicel Chemical Industries, Ltd.) (hereinafter abbreviated as “BTDA”) was gradually added to the flask and stirred for 8 hours while cooling with ice water. The reduced viscosity of the polyamic acid resin after the reaction was 1.27 dl / g. To 100 g of the polyamic acid varnish produced above (solid content concentration: 17.2 wt%), 2.1 g of diazabicycloundecene / p-toluenesulfonic acid (trade name: SA506, manufactured by San Apro Co., Ltd.) was added and stirred sufficiently. Thus, a resin composition varnish was obtained.
This varnish was applied onto a polyester film held on a smooth plate kept at 80 ° C., allowed to stand for 30 minutes, and then dried at 100 ° C. for 30 minutes in an air circulating drying oven to obtain a film. The thickness of the resin composition layer after drying was 40 μm. This film had an imidation ratio of 2% and a fluidity of 8.5% by mass, and showed a good fluidity.
From this film, the polyester film as the support film was peeled off, and heat treatment was carried out at 200 ° C. for 90 minutes in an air circulation type drying furnace. The imidation rate was 100%, and the water absorption rate was 0.8%. The results obtained are summarized in Table 1.

[Example 2]
A silica gel drying tube for absorbing water was attached to a 300-ml glass separable three-necked flask equipped with a stainless steel vertical stirrer. NMP256.3g and ODA13.5g were added to this flask at room temperature, and after stirring and dissolving, the flask was cooled with ice water. When the temperature of the liquid in the flask reached 5 ° C., 21.4 g of BTDA was gradually added to the flask and stirred for 8 hours while cooling with ice water. The reduced viscosity of the polyamic acid resin after completion of the reaction was 0.85 dl / g. To 100 g of the polyamic acid varnish produced above (solid content concentration: 17.2 wt%), 2.1 g of diazabicycloundecene / p-toluenesulfonic acid (trade name: SA506, manufactured by San Apro Co., Ltd.) was added and stirred sufficiently. Thus, a resin composition varnish was obtained. This varnish was applied on a polyester film held on a smooth plate kept at 80 ° C. and allowed to stand for 30 minutes, and then dried at 100 ° C. for 30 minutes in an air circulation type drying furnace to obtain a resin sheet. The thickness of the resin composition layer after drying was 40 μm. This film had an imidation ratio of 2% and a fluidity of 8.5% by mass, and showed a good fluidity. The support film was peeled from this film, and heat treatment was performed at 200 ° C. for 90 minutes in an air circulation type drying furnace. The imidization rate was 100% and the water absorption rate was 0.6%. The results obtained are summarized in Table 1.

[Example 3]
Based on 100 g of the polyamic acid varnish produced in Example 2 (solid content concentration: 17.2 wt%), 2.1 g of diazabicycloundecene / p-toluenesulfonic acid (trade name: SA506, manufactured by San Apro Co., Ltd.) Was added and sufficiently stirred to obtain a resin composition varnish. This resin composition varnish was spin-coated on a Si wafer so that the film thickness after drying was 17 μm, dried at 100 ° C. for 20 minutes, and then a polyamic acid film having an imidization ratio of 4% was obtained. When the coating film was completely dissolved using a 2.38 wt% TMAH aqueous solution at 23 ° C., it was 30 seconds per 1 μm film thickness.

[Comparative Example 1]
A film was obtained in the same manner except that diazabicycloundecene / p-toluenesulfonic acid was not added to 100 g (solid content concentration: 17.2 wt%) of the polyamic acid varnish produced in Example 1.
The thickness of the resin composition layer in the film after drying at 100 ° C. for 30 minutes was 40 μm. The composition of this resin composition layer had an imidation ratio of 2% and a fluidity of 8.2% by mass, indicating a good fluidity. The support film was peeled from this film, and heat treatment was performed at 200 ° C. for 90 minutes in an air circulation type drying furnace. The imidation rate was 92% and the water absorption rate was 2.2%. The results obtained are summarized in Table 1.
When this is compared with Example 1, the imidization rate after drying at 100 ° C. does not change in Example 1, and further, the imidation rate remains at 92% in Comparative Example 1 after heat treatment at 200 ° C. In Example 1, it is 100%, and it can be seen that the chemical imidizing agent of the present invention has desirable latent curability.

[Comparative Example 2]
To 100 g of the polyamic acid varnish produced in Example 1 (solid content concentration: 17.2 wt%), 5 g of diazabicycloundecene (manufactured by San Apro Co., Ltd.) was added and stirred sufficiently to obtain a resin composition varnish.
This varnish was applied onto a polyester film held on a smooth plate kept at 80 ° C., allowed to stand for 30 minutes, and then dried at 100 ° C. for 30 minutes in an air circulating drying oven to obtain a film. The thickness of the resin composition layer after drying was 40 μm. This film had an imidization ratio of 6%, a fluidity of 6% by mass, and the fluidity was slightly lowered.
The support film in this film was peeled off, and heat treatment was performed at 200 ° C. for 90 minutes in an air circulation type drying furnace. The imidization rate was 90%, and the water absorption rate was 2.4%. The results obtained are summarized in Table 1.

[Comparative Example 3]
To 100 g of the polyamic acid varnish produced in Example 1 (solid content concentration: 17.2 wt%), 8 g of diazabicycloundecene / p-toluenesulfonic acid was added and stirred sufficiently to obtain a resin composition varnish.
This varnish was applied onto a polyester film held on a smooth plate kept at 80 ° C., allowed to stand for 30 minutes, and then dried at 100 ° C. for 30 minutes in an air circulating drying oven to obtain a film. The thickness of the resin composition layer after drying was 40 μm. This film had an imidization ratio of 13% and a fluidity of 0% by mass, and good fluidity could not be obtained.
The support film was peeled from this film, and heat treatment was performed at 200 ° C. for 90 minutes in an air circulation type drying furnace. The imidation rate was 100%, and the water absorption rate was 0.8%. The results obtained are summarized in Table 1.

[Comparative Example 4]
1.8 g of 2-ethyl-4-methylimidazole was added to the polyamic acid varnish produced in Example 1, and the mixture was sufficiently stirred to obtain a resin composition varnish.
This varnish was applied onto a polyester film held on a smooth plate kept at 80 ° C., allowed to stand for 30 minutes, and then dried at 100 ° C. for 30 minutes in an air circulating drying oven to obtain a film. The thickness of the resin composition layer after drying was 40 μm. This film had an imidation ratio of 14% and a fluidity of 0.4% by mass, and good fluidity could not be obtained.
The support film in this film was peeled off, and heat treatment was performed at 200 ° C. for 90 minutes in an air circulation type drying furnace. The imidization rate was 100%, and the water absorption rate was 0.7%. The results obtained are summarized in Table 1.

[Comparative Example 5]
To 100 g of the polyamic acid varnish produced in Example 3, 1.8 g of 2-ethyl-4-methylimidazole (solid content concentration: 17.2 wt%) was added and stirred sufficiently to obtain a resin composition varnish. This resin composition varnish was spin-coated on a Si wafer so that the film thickness after drying was 17 μm, dried at 100 ° C. for 20 minutes, and then a polyamic acid film having an imidization ratio of 14% was obtained. When the coating film was completely dissolved using a 2.38 wt% TMAH aqueous solution at 23 ° C., it was 40 seconds per 1 μm.

  The polyimide precursor resin composition of the present invention is excellent in chemical resistance, low water absorption, adhesion, and heat resistance, and can be molded as necessary because it is not imidized when the solvent is dried. Therefore, it is suitable for insulating materials for multilayer wiring boards for electronic circuit boards and insulating protective film forming materials for electronic components such as semiconductor chips.

Claims (2)

a) a polyamic acid and b) a diazabicyclo derivative represented by the following general formula (I) as essential components, and a) component is 70 to 99.9 based on 100 parts by mass of the sum of components a) and b) It is a mass part, b) Component is 0.1-30 mass parts, The polyimide precursor resin composition characterized by the above-mentioned.

(In the general formula (I), m and n are independent integers, and m + n ≦ 8, m, and n ≧ 0. The order of the — (CH ₂ ) — group and the — (CH) — group) X is at least one group selected from —N (n—Bu) ₂ , CH ₃ and H, and R is an organic acid residue having 1 to 20 carbon atoms and / or an inorganic acid. Residue.)   The structure containing the polyimide resin formed by carrying out the imide ring closure of the polyimide precursor resin composition of Claim 1.