JP4009918B2 - Polyimide film, method for producing the same, and metal laminate using the same - Google Patents

Description

【表２】

【表３】

【００４１】
【発明の効果】
本発明で得られるポリイミドフィルムはブロック重合ポリイミド成分とランダム共重合ポリイミド成分とが分子結合によって構成された共重合ポリイミドを延伸して複屈折を０．０１以下、熱膨張係数を１０〜２２ｐｐｍ／℃にすることにより、機械特性が向上し、低熱膨張性、低吸水性を併せ持つことができ、さらに得られた金属積層板の反り量を低減できるので高い寸法安定性および高加工性を必要とする半導体パッケージ用途として充分機能を果たすことができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyimide film having high elasticity, low thermal expansion comparable to that of metals and low water absorption, a method for producing the same, and a metal laminate having improved warpage based thereon.
[0002]
[Prior art]
Polyimide obtained by polycondensation of pyromellitic anhydride and 4,4′-diaminodiphenyl ether is excellent in heat resistance and electrical insulation and is mainly used for applications such as flexible printed boards. Recently, it has also been developed for semiconductor package applications, and high workability and high precision are required. Polyimide properties are required to have high elastic modulus, low thermal expansion comparable to metal, and low water absorption, and various studies have been conducted. It has been broken. For example, in Japanese Patent Laid-Open Nos. 60-210629, 64-16832, 64-16883, 64-16834, 1-13-11241, and 1-113142, the elastic modulus is increased. Describes an example of a three-component polyimide using pyromellitic anhydride, 4,4′-diaminodiphenyl ether, and paraphenylenediamine in combination with paraphenylenediamine as a diamine component. In order to further increase the elastic modulus, development into a four-component polyimide in which 3,3′-4,4′-biphenyltetracarboxylic dianhydride is added to the above three-component system has also been performed. For example, JP-A 59-164328 and JP-A 61-111359 describe examples of quaternary polyimides. Another attempt to improve physical properties by controlling the monomer addition procedure during polymerization using a 4-component polyimide is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-25273. An attempt to improve the physical properties by stretching at the time of film formation is disclosed in, for example, JP-A-1-20238.
[0003]
[Problems to be solved by the invention]
As described above, in order to be used in semiconductor package applications, its properties require high elastic modulus, low thermal expansion comparable to metal, and low water absorption. However, the ternary polyimides obtained in JP-A-60-210629, JP-A-64-1683, JP-A-64-16833, JP-A-64-16834, JP-A-1-1311241, and JP-A-1-131242 are not anhydrous. Although the elastic modulus is higher than that of polyimide obtained from pyromellitic acid and 4,4′-diaminodiphenyl ether, it still cannot provide a sufficient elastic modulus for semiconductor package applications. In addition, in the four-component polyimides obtained in JP-A-59-164328 and JP-A-61-111359, in order to obtain a sufficient elastic modulus, it is necessary to increase the amount of paraphenylenediamine, and as a result, thermal expansion. There is a problem that the rate is too low than metal. In addition, the 4-component polyimide obtained in Japanese Patent Laid-Open No. 5-25273 has sufficient elasticity and thermal expansibility, but has a problem of high water absorption. In addition, the ternary polyimide obtained in JP-A-1-20238 has a remarkably high elastic modulus due to stretching, loses flexibility, significantly reduces the coefficient of thermal expansion, and increases the difference in thermal behavior with metal when bonded to a film. There's a problem.
[0004]
Accordingly, it is an object of the present invention to provide a polyimide film having high elasticity, low thermal expansion comparable to metals, and low water absorption, a method for producing the polyimide film, and a metal laminate having improved warpage using the polyimide film.
[0005]
[Means for Solving the Problems]
The polyimide film of the present invention that solves the above problems includes a polyimide block component comprising paraphenylenediamine and pyromellitic dianhydride, 4,4′-diaminodiphenyl ether, pyromellitic dianhydride, and 3,3 ′. , 4,4′-biphenyltetracarboxylic dianhydride or 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride copolymerized polyimide random component and a copolymer formed by molecular bonding A polyimide film formed by biaxially stretching polyimide with a birefringence of 0.01 or less, a thermal expansion coefficient of 10 to 22 ppm / ° C., an elastic modulus of 520 to 680 kg / mm ² , and a water absorption of 1.5 to 2.1%.
(However, in the wholly aromatic diamine component, paraphenylenediamine is 12 to 30 mol%, 4,4′-diaminodiphenyl ether is 70 to 88 mol%, and pyromellitic dianhydride in the wholly aromatic tetracarboxylic acid component. Is 50 to 80 mol%, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride or 3,3', 4,4'-benzophenonetetracarboxylic dianhydride is 20 to 50 mol% .)
Moreover, the manufacturing method of the polyimide film of the present invention is as follows: (1) In a non-reactive organic solvent with respect to the reaction component, pyrophenylene diamine and pyromellitic dianhydride with respect to paraphenylene diamine. After mixing for the time required for the reaction at a ratio of 95 to 105 mol% of acid dianhydride, (2) 4,4′-diaminodiphenyl ether is added, followed by addition of pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride or 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride is converted into a wholly aromatic tetracarboxylic acid component and a wholly aromatic diamine component. Is added in an amount of approximately equimolar, and mixed for the time required for the reaction. (3) The resulting copolymerized polyamic acid solution is cyclized, and then biaxially stretched and desolvated to form. A method for producing Li imide film.
Moreover, the metal laminated board of this invention is a metal laminated board characterized by laminating | stacking this and a metal on the basis of said polyimide film or the polyimide film obtained by said method.
[0006]
The polyimide block component constituting the copolymerized polyimide of the present invention is a repeating polyimide molecular chain obtained from paraphenylenediamine (hereinafter sometimes referred to as a rigid aromatic diamine compound) and pyromellitic dianhydride. And obtained by forming in the first stage of polymerization. The random component of the copolymerized polyimide comprises 4,4′-diaminodiphenyl ether (hereinafter sometimes referred to as a flexible diamine compound), pyromellitic dianhydride, and 3,3 ′, 4 in the second stage of polymerization. , 4′-biphenyltetracarboxylic dianhydride or 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride . The polyimide film formed by stretching the copolymerized polyimide, which comprises the polyimide block component and the random component of the copolymerized polyimide by molecular bonding, is excellent in high elasticity, low thermal expansion comparable to metals, and low water absorption. It can have physical properties.
[0007]
The birefringence of the polyimide film obtained by stretching needs to be controlled to 0.01 or less. A birefringence of 0.01 or more is not preferable because the anisotropy of the film increases and warpage is likely to occur when bonded to a metal.
[0008]
Further, it is desirable to control the thermal expansion coefficient of the polyimide film obtained by stretching in the range of 10 to 22 ppm / ° C. Outside this range, there may be differences in the thermal behavior of metals, IC chips, epoxy substrates, etc., and the dimensional change becomes large, which may be undesirable.
[0015]
The ratio of the aromatic diamine compound used is 12 mol% to 30 mol% of the rigid aromatic diamine compound and 70 mol% to 88 mol of the flexible aromatic diamine compound with respect to the total aromatic diamine component. % Or less is preferably used. If the use ratio of the rigid structure aromatic diamine compound is less than the above ratio and the use ratio of the flexible structure aromatic diamine compound is too large, the elastic modulus of the resulting polyimide film is decreased, or the thermal expansion coefficient is It is not preferable because it increases, and if the use ratio of the aromatic diamine compound having a rigid structure is larger than the above ratio and the use ratio of the aromatic diamine compound having a flexible structure is decreased, the water absorption rate of the polyimide film increases, This is not preferable because the expansion coefficient is too low or the elastic modulus is too high and the moldability is impaired.
[0016]
As the aromatic tetracarboxylic acid compound to be used, one or more selected from pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid and 3,3 ′, 4,4′-benzophenonetetracarboxylic acid are selected. Is preferred.
[0017]
The aromatic tetracarboxylic acid compound used is pyromellitic acid or its dianhydride as pyromellitic acid, and 3,3'-4,4 'as 3,3'-4,4'-biphenyltetracarboxylic acid. -Biphenyltetracarboxylic acid or its dianhydride, and 3,3'-4,4'-benzophenonetetracarboxylic acid as 3,3'-4,4'-benzophenonetetracarboxylic acid or its dianhydride, respectively. be able to.
[0018]
As a ratio of the aromatic tetracarboxylic acid compound to be used, pyromellitic acid is 50 mol% or more and 80 mol% or less, 3,3′-4,4′-biphenyl tetracarboxylic acid, based on the total aromatic tetracarboxylic acid component. And / or 3,3′-4,4′-benzophenonetetracarboxylic acid is preferably used in an amount of 20 mol% to 50 mol%. When the usage ratio of 3,3′-4,4′-biphenyltetracarboxylic acid and / or 3,3′-4,4′-benzophenonetetracarboxylic acid is less than the above ratio, the elastic modulus of the resulting polyimide film Is not preferable because of a decrease in water content and an increase in water absorption, and the proportion of 3,3′-4,4′-biphenyltetracarboxylic acid and / or 3,3′-4,4′-benzophenonetetracarboxylic acid used If the ratio is larger than the above-mentioned ratio, the gas permeability of the resulting polyimide film is deteriorated, and bubbles are generated on the surface of the film or the adhesive strength of the film is lowered. Incidentally, 3,3′-4,4′-biphenyltetracarboxylic acids and 3,3′-4,4′-benzophenonetetracarboxylic acids may be used alone or in combination.
[0019]
Next, the manufacturing method of the polyimide film of this invention is demonstrated. First, in order to form a polyimide block component, a rigid aromatic diamine compound and one aromatic tetracarboxylic acid in a first stage of polymerization are reacted in a non-reactive organic solvent with a reactive component. Mix for at least 1 hour. The ratio of the aromatic tetracarboxylic acid to the aromatic diamine compound used here is preferably 95 to 105 mol%. However, in order to efficiently form a block component and molecularly bond with the random component formed in the second stage, 97 to 100 mol% is more preferable.
[0020]
Subsequently, in order to form a random component of the copolymerized polyimide, a flexible aromatic diamine compound is added as the second stage of polymerization, then the aromatic tetracarboxylic acid (A) is added and stirred for 1 hour or more, and further aromatic Tetracarboxylic acids (B; A ≠ B) are added in an amount such that the wholly aromatic tetracarboxylic acid component and the wholly aromatic diamine component are approximately equimolar, and stirred for 1 hour or longer. During such a series of polymerizations, it is possible to obtain a copolymerized polyamic acid solution in which the block polymerized polyamic acid component and the random copolymerized polyamic acid component formed in the first stage and the second stage, respectively, are molecularly bonded. A desired polyimide film can be obtained by stretching and removing the solvent after cyclization of the acid solution.
[0021]
The stretching in the production method will be described. First, the polyamic acid obtained by a series of reactions is chemically cyclized using a cyclization catalyst and a dehydrating agent, or thermally cyclized by heat treatment to obtain a polyimide gel film. Next, it is preferable to fix the edge part of this gel film, and to extend | stretch by the magnification of 1.05-1.5 in the vertical direction, and 1.05-2.0 in the horizontal direction. It is preferable to perform such biaxial stretching because the resulting polyimide film has improved mechanical properties and isotropic properties.
[0022]
In the first stage polymerization in the production method, any of pyromellitic acids, 3,3′-4,4′-biphenyltetracarboxylic acids, 3,3′-4,4′-benzophenonetetracarboxylic acids as aromatic tetracarboxylic acids However, although it may be used alone, it is preferable to use pyromellitic acids because the elastic modulus of the finally obtained polyimide film is increased. A rigid aromatic diamine compound is used as the aromatic diamine component.
[0023]
In the second stage polymerization, the aromatic tetracarboxylic acids are selected from pyromellitic acids, 3,3′-4,4′-biphenyltetracarboxylic acids and 3,3′-4,4′-benzophenonetetracarboxylic acids 1 It is preferable to use more than one kind of compound, and in order to increase the elastic modulus of the finally obtained polyimide film, a combination of pyromellitic acids and 3,3′-4,4′-biphenyltetracarboxylic acids is used. Is preferred. A flexible aromatic diamine compound is used as the aromatic diamine component.
[0024]
Solvents used in the production method include dimethyl sulfoxide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone and dimethyl Examples thereof include sulfones, and these are preferably used alone or in combination.
[0025]
The copolymerized polyamic acid obtained by the production method is prepared in a proportion of 10 to 30% by weight in the solvent.
[0026]
When the copolymerized polyamic acid obtained by the production method is cyclized to form a copolymerized polyimide, either a chemical ring closure method using a dehydrating agent and a catalyst or a thermal ring closure method in which thermal dehydration is performed may be used. However, it is preferable to use the chemical ring closure method because the polyimide film obtained has a high elastic modulus, a low thermal expansion coefficient, and chemical etching properties necessary for TAB applications. Examples of the dehydrating agent used in the chemical ring closure method include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as phthalic anhydride, and these are preferably used alone or in combination. Examples of the catalyst include heterocyclic tertiary amines such as pyridine, picoline and quinoline, aliphatic tertiary amines such as triethylamine, and aromatic tertiary amines such as N, N-dimethylaniline. These are preferably used alone or in combination.
[0027]
The metal laminate of the present invention has a three-layer structure in which a conductive metal foil is laminated on the surface of a polyimide film as a base material via an adhesive such as a polyester base, an acrylic base, an epoxy base or a polyimide base. Any of a two-layer structure in which a conductive metal layer is directly laminated on the surface of a polyimide film without using an adhesive may be used.
[0028]
【Example】
Hereinafter, the present invention will be described by way of specific examples. In the examples, PPD is paraphenylenediamine, ODA is 4,4′-diaminodiphenyl ether, PMDA is pyromellitic dianhydride, BPDA is 3,3′-4,4′-diphenyltetracarboxylic dianhydride, BTDA is 3,3′-4,4′-benzophenonetetracarboxylic dianhydride, DMAc represents N, N-dimethylacetamide.
[0029]
Example 1
DMAc 239.1g was put into a 500 ml separable flask, PPD1.870g (0.0173mol) and PMDA3.659g (0.0168mol) were thrown in here, and it was made to react at normal temperature normal pressure for 1 hour. Next, ODA25.398g (0.1268mol) was thrown here and it stirred until it became uniform, Then, BPDA8.481g (0.0288mol) was added, and it was made to react for 1 hour. Subsequently, 21.491 g (0.0985 mol) of PMDA was added thereto, and the mixture was further reacted for 1 hour to obtain a polyamic acid solution. In this polymerization, the addition molar ratio of each raw material was carried out at the ratio shown in Table 1, and the total solid content weight was adjusted to 60.9 g. 15 g of this polyamic acid solution was taken and placed on a 125 μm-thick polyester film, and then rotated for 1 minute at a rotation speed of 2500 rpm with a 1H-360S spin coater manufactured by Mikasa. Subsequently, this was immersed in a mixed solution of acetic anhydride and β-picoline for 10 minutes to cause an imidization reaction, and then the polyimide gel film was peeled off from the polyester film, and the end of the gel film was pinned, and the longitudinal direction was 1.15 times. The film was stretched 1.30 times in the transverse direction. Then, after heat-drying at 300 ° C. for 20 minutes and then at 400 ° C. for 5 minutes, the pinning was removed to obtain a polyimide film having a thickness of about 25 μm. Each characteristic of this film was evaluated, and the results are shown in Table 1.
[0030]
Each characteristic was evaluated by the following method.
[0031]
(Evaluation methods)
(1) Elastic modulus equipment: RTM-250
Tensile speed: 100 mm / min
Load: 10kg
(2) Coefficient of thermal expansion: TMA-50
Measurement temperature range: 50-200 ° C
Temperature increase rate: 10 ° C / min
(3) Water absorption rate: 98% The sample was allowed to stand in a desiccator under an RH atmosphere for 2 days, and evaluated by an increase in weight% relative to the original weight.
[0032]
(4) Birefringence equipment: KOBRA-21ADH
Light source: Sodium light incident angle: 0 ° Measurement formula: ΔN _xy = (retardation) / film thickness
(5) Evaluation of warpage amount of metal laminate plate An epoxy-based adhesive was applied to a polyimide film, and a copper foil was bonded thereto at a temperature of 130 ° C. Thereafter, the temperature is raised to a maximum temperature of 160 ° C. to cure the adhesive, and the obtained metal laminate is cut into a sample size of 35 mm * 120 mm and left at 25 ° C. and 60 RH% for 24 hours, and then the warpage of each sample is performed. Was measured. The warpage was evaluated by placing the sample on a flat ground and measuring and averaging the heights of the four corners. When the amount of warpage exceeds 3 mm, when it is used as a metal laminate, it is often difficult to handle in a subsequent process.
[0033]
Examples 2-10
In the same procedure as in Example 1, after obtaining the polyamic acid solution in the ratio shown in Table 1 for the aromatic diamine component and the aromatic tetracarboxylic acid component, the stretching ratios in the transverse and longitudinal directions are as shown in Table 1. Each characteristic evaluation of the polyimide film obtained by the same operation as Example 1 was performed, and the results are shown in Table 1. Table 3 shows the results of warpage of the metal laminate for the polyimide film obtained in Example 3 (thermal expansion coefficient: 17.5 ppm / ° C., birefringence 0.0094).
[0034]
Example 11
A polyimide obtained by the same operation as in Example 1, after replacing BPDA with BTDA and performing the same procedure as in Example 1 to obtain a polyamic acid solution, except that the addition amount of raw materials was changed as shown in Table 1. The physical properties of the film were evaluated, and the results are shown in Table 1.
[0035]
Example 12
DMAc 239.1g was put into a 500 ml separable flask, PPD and BPDA were put here, and it was made to react at normal temperature normal pressure for 1 hour. Next, ODA was added here and stirred until uniform, then BPDA was added and allowed to react for 1 hour. Subsequently, PMDA was added thereto and reacted for another hour to obtain a polyamic acid solution. In addition, the addition amount of each raw material was performed by this polymerization in the ratio shown in Table 1, and the total solid content weight was adjusted to 60.9 g. Thereafter, an operation for obtaining a polyimide film from the polyamic acid solution was carried out in the same manner as in Example 1. Table 1 shows the results of evaluation of physical properties of the polyimide film.
[0036]
Comparative Example 1
After reacting and imidizing the aromatic diamine component and aromatic tetracarboxylic acid component in the same proportions and procedure as in Example 1, the ends were pinned without stretching, and then at 300 ° C. for 20 minutes, followed by After heat drying at 400 ° C. for 5 minutes, the pinning was removed, and a polyimide film having a thickness of about 25 μm was obtained. The physical property evaluation results of this film are shown in Table 2.
[0037]
Comparative Example 2
DMAc 239.1g was put into a 500 ml separable flask, ODA and PMDA were put here, and it was made to react at normal temperature normal pressure for 1 hour, and the polyamic-acid solution was obtained. The molar ratio of ODA to PMDA was approximately 1: 1, and the total solid content weight was adjusted to 60.9 g. Thereafter, the operation for obtaining the polyimide film from the polyamic acid solution was carried out in the same manner as in Example 1 except that the transverse and longitudinal stretching ratios were as shown in Table 2, and the physical property evaluation results of the obtained polyimide film were obtained. Are shown in Table 2.
[0038]
Comparative Example 3
DMAc 239.1g was put into a 500 ml separable flask, PPD and PMDA were added here, and it was made to react at normal temperature normal pressure for 1 hour. Next, ODA was added thereto and stirred until uniform, then PMDA was added and reacted for 1 hour to obtain a polyamic acid solution. In this polymerization, the amount of each raw material was added in the ratio shown in Table 2, and the total solid content weight was adjusted to 60.9 g. Thereafter, the operation for obtaining the polyimide film from the polyamic acid solution was carried out in the same manner as in Example 1 except that the transverse and longitudinal stretching ratios were as shown in Table 2, and the physical property evaluation results of the obtained polyimide film were obtained. Are shown in Table 2. Table 3 shows the results of warpage of the metal laminate of the obtained polyimide film.
[0039]
Comparative Example 4
239.1 g of DMAc was put into a 500 ml separable flask, and PPD, ODA, BPDA and PMDA were sequentially added thereto and reacted at room temperature and normal pressure for 2 hours to obtain a polyamic acid solution. In this polymerization, the amount of each raw material was added in the ratio shown in Table 2, and the total solid content weight was adjusted to 60.9 g. Thereafter, the operation for obtaining the polyimide film from the polyamic acid solution was carried out in the same manner as in Example 1 except that the transverse and longitudinal stretching ratios were as shown in Table 2, and the physical property evaluation results of the obtained polyimide film were obtained. Are shown in Table 2.
[0040]
[Table 1]

[Table 2]

[Table 3]

[0041]
【The invention's effect】
The polyimide film obtained in the present invention is obtained by stretching a copolymerized polyimide in which a block polymerized polyimide component and a random copolymerized polyimide component are formed by molecular bonding to have a birefringence of 0.01 or less and a thermal expansion coefficient of 10 to 22 ppm / ° C. By improving the mechanical properties, it is possible to have both low thermal expansibility and low water absorption, and the amount of warpage of the obtained metal laminate can be reduced, so that high dimensional stability and high workability are required. It can sufficiently function as a semiconductor package application.

Claims (4)

Polyimide block component consisting of paraphenylenediamine and pyromellitic dianhydride , 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride birefringence object or 3,3 ', and a random component of the copolymerized polyimide consisting of 4,4'-benzophenonetetracarboxylic acid dianhydride was molded by biaxially stretching the copolymer polyimide obtained by molecular bonding A polyimide film having a thermal expansion coefficient of 10 to 22 ppm / ° C., an elastic modulus of 520 to 680 kg / mm ² and a water absorption of 1.5 to 2.1%.
(However, in the wholly aromatic diamine component, paraphenylenediamine is 12 to 30 mol%, 4,4′-diaminodiphenyl ether is 70 to 88 mol%, and pyromellitic dianhydride in the wholly aromatic tetracarboxylic acid component . Is 50 to 80 mol%, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride or 3,3', 4,4'-benzophenonetetracarboxylic dianhydride is 20 to 50 mol% .) (1) a para-phenylenediamine and pyromellitic dianhydride, a non-reactive organic solvent to the reaction components, pyromellitic dianhydride is 95 to 105 mol% based on p-phenylenediamine After mixing for the time required for the reaction in the ratio,
(2) 4,4′-diaminodiphenyl ether is added, followed by pyromellitic dianhydride , followed by 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride or 3,3 ′, 4 , 4'-benzophenonetetracarboxylic dianhydride is added in an amount such that the wholly aromatic tetracarboxylic acid component and the wholly aromatic diamine component are approximately equimolar, and mixed for the time required for the reaction,
(3) A method for producing a polyimide film, wherein the resulting copolymerized polyamic acid solution is cyclized and then formed by biaxial stretching and desolvation. The method for producing a polyimide film according to claim 2 , wherein the cyclization is performed by a chemical cyclization method using a cyclization catalyst and a dehydrating agent. The polyimide film of claim 1 wherein Alternatively, a polyimide film obtained in claim 2 or 3, wherein the method as a base material, metal laminate, which comprises laminating a metal thereto.