KR20070106779A - Laminate for wiring board - Google Patents

Abstract

Disclosed is a laminate for wiring boards comprising an aromatic polyimide resin layer which has excellent heat resistance, thermal dimensional stability and adequate elastic modulus, while realizing low moisture absorption, low moisture expansion coefficient and low permittivity. The aromatic polyimide resin layer is suppressed in warping without suffering from problems caused by an adhesive layer. Specifically disclosed is a laminate for wiring boards wherein a metal foil is arranged on one or both sides of polyimide resin layers, and at least one of the polyimide resin layers contains not less than 10% by mole of a constitutional unit represented by the following general formula (1). In the formula, Ar1 represents a tetravalent organic group having one or more aromatic rings and R represents a hydrocarbon group having 2-6 carbon atoms.

Description

Laminated body for wiring board {LAMINATE FOR WIRING BOARD}

The present invention relates to a laminate for wiring boards that can be used for flexible printed wiring boards, HDD suspensions, and the like.

Background Art In recent years, high performance, high functionality, and miniaturization of electronic devices have been rapidly progressed, and the demand for higher density and higher performance has increased for electronic components used in electronic devices and substrates on which they are mounted. With regard to the flexible printed wiring board (hereinafter referred to as "FPC"), thin wire processing, multilayer formation, and the like are performed, and the thinning and dimensional stability of the material constituting the FPC are strictly required.

In general, a film made of polyimide resin excellent in various properties is widely used as the insulating film of FPC, and epoxy resin and acrylic resin excellent in low temperature processability are used as the insulating adhesive layer between the insulating film and the metal. However, these adhesive layers have a problem of causing deterioration of heat resistance and thermal dimensional stability.

In order to solve such a problem, in recent years, the method of coating and forming a polyimide resin layer directly on metal foil, without forming an adhesive layer, is employ | adopted. Patent Document 1 discloses a method of providing an FPC excellent in adhesive strength and thermal dimensional stability by multilayering a polyimide resin layer on a plurality of polyimides having different thermal expansion coefficients. However, since these polyimides have high hygroscopicity, problems such as components when immersed in a solder bath or poor connection due to dimensional change after moisture absorption during thin wire processing are caused. Since the humidity expansion coefficient was close to zero or zero, the dimensional change after the moisture absorption caused the defects such as warpage, curling, and twisting of the laminate.

As a prior art document related to the present invention, there are the following documents.

Patent Document 1: Patent Publication No. Hei 2-225522

Patent Document 2: Patent Publication No. 2001-11177

Patent Document 3: Patent Publication No. Hei 8-217877

Patent Document 4: Patent Publication No. 2000-63543

Patent Document 5: Korean Patent Application Laid-Open No. 01-261421

Patent Document 6: W001 / 28767Al

From these backgrounds, in recent years, the demand for polyimide resin having excellent low hygroscopicity and post-moisture dimensional stability has been increasing, and various studies have been conducted on it. For example, in Patent Literatures 1 and 2, polyimide that improves hydrophobicity and exhibits low hygroscopicity by introducing fluorine-based resins has been proposed, but there are disadvantages in that the manufacturing cost increases or the adhesion with a metal material is poor. . Also in the case of coping with other low hygroscopicity, as shown in Patent Literatures 3 to 4 and the like, good characteristics of polyimide such as low hygroscopicity and low thermal expansion coefficient were exhibited, but high heat resistance could not be retained.

In addition, although the polyimide has the structure which the tetracarboxylic dianhydride component and the diamine component couple | bonded alternately, the polyimide using diamino biphenyl or the diamino biphenyls which methoxy substituted into this diamine is patent document 2 Although illustrated in, the specific example is not shown and cannot predict what kind of characteristics they have.

Moreover, in patent documents 5-6, the monomer which gives a high heat resistance, a high elastic modulus, and low absorption polyimide resin is proposed. However, since the polyimide resin described here is rigid, it was high in elastic modulus. In recent years, the laminated board used for the flexible printed wiring board which uses a polyimide as an insulating layer is used for bending applications, such as a mobile telephone. And when it applies to such a use, the moderate elasticity modulus which is not too rigid is calculated | required, and the balance with the other material property is satisfied, and the reliability to the laminated board in the said use is satisfied. When polyimide resin is used as an insulating layer such as a wiring board, high-speed transfer of information may be required, and in that case, low dielectric constant and low dielectric loss tangent are required as electrical characteristics of the polyimide. Since polyimide contains a strong imide group, most have a dielectric constant of 3.5 or more, and development of a lower dielectric constant material was expected.

Therefore, the present invention solves the above-mentioned problems, and has a laminate for wiring boards having an aromatic polyimide layer which has excellent heat resistance, thermal dimensional stability, moderate elastic modulus, and at the same time realizes low hygroscopicity, low humidity expansion coefficient and low dielectric property. It aims to provide.

That is, the present invention provides a laminate having metal foil on one or both sides of the polyimide resin layer, wherein at least one layer of the polyimide resin layer contains 10 mol% or more of the structural unit represented by the following general formula (1). It is a laminated body for wiring boards characterized by the above-mentioned.

(In the formula, Ar ₁ is a tetravalent organic group having one or more aromatic rings, and R is a hydrocarbon group having 2 to 6 carbon atoms.)

EMBODIMENT OF THE INVENTION Below, the laminated body for wiring boards of this invention is demonstrated.

The laminate for wiring boards of the present invention has a structure in which metal foil is laminated on one side or both sides of one or multiple layers of polyimide resin layers. As the metal foil, a copper foil having a thickness of 10 to 50 µm is suitable for use in a flexible printed wiring board, and a stainless steel foil having a thickness of 10 to 70 µm is suitable when used as a substrate for HDD suspension. At least one layer of the polyimide resin layer contains 10 mol% or more of the structural unit represented by the general formula (1). In this specification, the polyamic acid of such a polyimide resin or its precursor is also called this polyimide resin or this polyamic acid, and the layer formed hereafter is also called this polyimide resin layer or this polyamic acid layer.

In the structural unit represented by General formula (1), Ar1 is a tetravalent organic group which has one or more aromatic rings, and can be called aromatic tetracarboxylic acid residue made from aromatic tetracarboxylic acid, its acid dianhydride, etc. Therefore, Ar ₁ is understood by explaining the aromatic tetracarboxylic acid to be used. Usually, it will be described the case to synthesize a polyimide or a polyamic acid having the structural unit, since the aromatic tetracarboxylic this there is much that anhydride is used, the preferred Ar _1, below with an aromatic tetracarboxylic acid is used the anhydride .

It does not specifically limit as said aromatic tetracarboxylic dianhydride, A well-known thing can be used. Specific examples include pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 2, 3,3 ', 4'-benzophenone tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene- 1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8- Dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7- Hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4, 5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene 1,4,5,8-tetracarboxylic dianhydride, 1,4,5,8-tetrachloronaphthalene-2,3 , 6,7-tetracarbonic acid Anhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 2,3,3 ', 4'-biphenyl Tetracarboxylic dianhydride, 3,3 '', 4,4 ''-p-terphenyltetracarboxylic dianhydride, 2,2 '', 3,3 ''-p-terphenyltetracarboxylic dianhydride, 2,3,3 '', 4 ''-p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -propane dianhydride, 2,2-bis (3,4 Dicarboxyphenyl) -propane dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride , Bis (2,3-dicarboxyphenyl) sulfon dianhydride, bis (3,4-dicarboxyphenyl) sulfon dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1 -Bis (3,4-dicarboxyphenyl) ethane dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, phen Relene-4,5,10,11-tetraka Levonic dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7- Tetracarboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6- Tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-oxydiphthalic acid Anhydrides etc. are mentioned. In addition, these can be used individually or in mixture of 2 or more types.

Among these, pyromellitic dianhydride (PMDA), naphthalene-2,3,6,7-tetracarboxylic dianhydride (NTCDA) and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) Is preferably selected from. In particular, in order to realize a low thermal expansion coefficient, it is preferable to use PMDA or NTCDA. By mixing and using an appropriate amount of BPDA to this, it can adjust to the thermal expansion coefficient of the same grade as a metal foil, and can adjust to the value below 20 ppm / degreeC practically required. It is possible to suppress generation | occurrence | production of curvature, curl, etc. of a laminated body by this. Although these aromatic tetracarboxylic dianhydride can also be used together with another aromatic tetracarboxylic dianhydride, it is good to use 50 mol% or more of the whole, Preferably it is 70 mol% or more. That is, in selecting tetracarboxylic dianhydride, it is preferable to specifically select the thing suitable for expressing the characteristic required by the purpose of use, such as the thermal expansion coefficient of a polyimide obtained by superposition | polymerization heating, a thermal decomposition temperature, and a glass potential temperature.

The diamine used as an essential component in the synthesis | combination of the polyimide resin used by this invention is an aromatic diamine represented by following General formula (2).

Here, R has the same meaning as R in general formula (1) and is a C2-C6 hydrocarbon group, Preferably it is an ethyl group, a propyl group, or a phenyl group.

The polyimide resin used in the present invention is advantageously obtained by reacting an aromatic tetracarboxylic dianhydride with a diamine containing 10 mol% or more of the aromatic diamine represented by the general formula (2).

In this invention, other diamine other than that can be used with the aromatic diamine represented by the said General formula (2) in 90 mol% or less, and it can be set as a copolymerized polyimide by this.

The structural unit represented by the general formula (1) is 10 to 100 mol%, preferably 50 to 100 mol%, more preferably 70 to 100 mol%, still more preferably 90 to 1 layer of the polyimide resin layer. It is good to contain 100 mol%.

In addition to the aromatic diamine represented by General formula (2), although it does not specifically limit as diamine used for copolymerization, For example, 4, 6- dimethyl- m-phenylenediamine, 2, 5- dimethyl- p-phenylene Diamine, 2,4-diaminomethylene, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xyldine, 4,4'-methylene-2,6- Diethylaniline, 2,4-toluenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'- Diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 2,2-bis [4- (4- Aminophenoxy) phenyl] propane, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 3,3'-diamino Diphenylsulfone, 4,4'-diaminodiphenylether, 3,3-diaminodiphenylether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy ) Benzene, 1,4-bis (4-aminophenoxy) benzene, benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3 ' -Dimethoxybenzidine, 4,4'-diamino-p-terphenyl, 3,3'-diamino-p-terphenyl, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t -Butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5 aminopentyl ) Benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5 -Diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino- 1,3,4-oxadiazole, piperazine, 2,2'-dimethyl-4,4'- diaminobiphenyl, etc. are mentioned.

Among these, 4,4'- diamino diphenyl ether (DAPE), 1, 3-bis (4-aminophenoxy) benzene (TPE-R), p-phenyldiamine (p-PDA), 2,2'- Dimethyl-4,4'-diaminobiphenyl (m-TB) etc. are used preferably. Moreover, when using these diamine, the use ratio becomes like this. Preferably it is 0-50 mol% of a total diamine, More preferably, it is the range of 0-30 mol%.

The polyamic acid which becomes a precursor of a polyimide resin can be manufactured by the well-known method of superposing | polymerizing in an organic solvent using the aromatic diamine component and aromatic tetracarboxylic dianhydride component shown above in 0.9-1.1 molar ratio. That is, after dissolving aromatic diamine in organic solvents, such as N, N- dimethylacetamide and N-methyl- 2-pyrrolidone, under nitrogen stream, aromatic tetracarboxylic dianhydride is added, and it is about 3 to 4 hours at room temperature. It is obtained by making it react. At this time, the molecular terminal may be sealed with an aromatic monoamine or dicarboxylic acid anhydride.

When using the aromatic tetracarboxylic dianhydride component containing a naphthalene skeleton, for example, after melt | dissolving an aromatic diamine component in m-cresol under nitrogen stream, the catalyst and aromatic tetracarboxylic dianhydride component are added and 190 degreeC It is obtained by heating at for 10 hours and then reacting for 8 hours after returning to room temperature.

The polyamic acid solution obtained by the said reaction is apply | coated using the applicator on the adhesive layer formed on the metal foil shape or metal foil used as a support body, and is imidated by the thermal imidation method or the chemical imidation method, The laminated body for wiring boards of this invention is obtained. Thermal imidation is performed by pre-drying for 2 to 60 minutes at the temperature of 150 degrees C or less, and then heat-processing about 2 to 30 minutes at the temperature of about 130-360 degreeC normally. Chemical imidation is performed by adding a dehydrating agent and a catalyst to this polyamic acid. At this time, as metal foil used, copper foil or SUS foil is preferable, The preferable thickness range is 50 micrometers or less, Advantageously, it is 5-40 micrometers. The thinner one is suitable for formation of a fine pattern, and from such a viewpoint, the range of 8-15 micrometers is preferable.

The polyimide resin layer may be a single layer or a multilayer. In the case of a multilayer polyimide resin layer, the operation of applying and drying a polyamic acid solution is repeated, followed by heat treatment to remove the solvent, followed by further heat treatment to imide to form a polyimide resin layer having a multilayer structure. can do. At this time, the total thickness of the polyimide resin layer formed is preferably in the range of 3 to 75 µm. In the case of a multilayer, at least one layer thereof needs to be a layer of the present polyimide resin containing 10 mol% or more of the structural unit represented by the general formula (1), and the thickness thereof is 30% or more of the entire polyimide resin layer, Preferably it is 50% or more, More preferably, it is good to set it as 70% or more. When it has another polyimide resin layer, it is good that this polyimide resin layer is a layer (adhesive layer) which contact | connects with metal foil.

In addition, when manufacturing the laminated body for wiring boards which has metal foil on both surfaces, after forming a direct or adhesive layer on the polyimide resin layer of the laminated body for single-sided wiring board obtained by the said method, it is obtained by heat-pressing a metal foil. Lose. Although it does not specifically limit about the heat press temperature at the time of this hot pressing, It is preferable that it is more than the glass potential temperature of the polyimide resin used. Moreover, although it depends also on the kind of press apparatus to be used about a hot press pressure, it is preferable that it is the range of 1-500 kg / cm <^2> . Moreover, the preferable metal foil used at this time can use the same thing as said metal foil, The preferable thickness is 50 micrometers or less, More preferably, it is the range of 5-40 micrometers.

The polyimide resin layer which comprises the laminated body for wiring boards of this invention is various combinations of the aromatic diamine represented by General formula (2), the other aromatic diamine used with this, aromatic tetracarboxylic acid, or its acid dianhydride. The characteristics can be controlled by Among them, the preferred polyimide resin layer has a coefficient of linear expansion of 25 ppm / ° C. or less, a storage modulus of 6 GPa or less at 23 ° C., and a humidity expansion coefficient of 5 ppm /% RH or less, and at a glass potential temperature of 350 ° C. in terms of heat resistance. The pyrolysis temperature (Td5%), which is a 5% weight loss temperature in the thermogravimetric analysis, is above 450 ° C. Moreover, in the preferable polyimide resin layer which comprises the laminated body for wiring boards of this invention, dielectric constant in 15GHz is 3.2 or less, More preferably, it is the range of 1-3.1. In particular, by setting the storage modulus of the polyimide resin layer to be in the range of 2 to 6 GPa, the laminate for wiring boards suitable for bending applications can be obtained. In addition, when a polyimide resin layer consists of multiple layers, the said numerical value is a numerical value as a whole.

In the laminate for a wiring board of the present invention, since the polyimide resin layer has the present polyimide resin layer, the polyimide resin layer serving as the insulating layer is excellent in heat resistance, low moisture absorption, low dielectric constant, and also excellent in dimensional stability. It also has the effect of suppressing warping due to humidity without being accompanied. In addition, since the polyimide resin layer of the insulating layer has a small difference in the humidity expansion coefficients in the TD direction and the MD direction, it is characterized in that it is not anisotropic in plane and can be widely applied to components in the field of electronic materials. It is especially useful for applications, such as a board | substrate for FPC and HDD suspension.

EMBODIMENT OF THE INVENTION Hereinafter, although the content of this invention is demonstrated concretely based on an Example, this invention is not limited to the range of these Examples.

The symbol used in the Example etc. is shown below.

PMDA: pyromellitic dianhydride

BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride

M-EB: 2,2'-diethyl-4,4'-diaminobiphenyl

M-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl

M-NPB: 2,2'-di-n-propyl-4,4'-diaminobiphenyl

DAPE: 4,4'-diaminodiphenyl ether

TPE-R: 1,3-bis (4-aminophenoxy) benzene

BAPP: 2,2'-bis (4-aminophenoxyphenyl) propane

DMF: N, N-dimethylformamide

DMAc: N, N-dimethylacetamide

In addition, the measuring method and conditions of various physical properties in an Example are shown below.

[Glass Potential Temperature (Tg), Storage Modulus (E ')]

Dynamic viscoelasticity was measured when the polyimide film (10 mm x 22.6 mm) obtained in each example was heated up at 5 ° C / min from 20 ° C to 500 ° C with a dynamic thermomechanical analyzer (DMA), and the glass potential temperature (tanδ) was measured. Maximum value) and storage modulus (E ') at 23 ° C.

[Measurement of linear expansion coefficient (CTE)]

A polyimide film having a size of 3 mm x 15 mm was subjected to a tensile test at a temperature range of 30 ° C. to 260 ° C. at a constant heating rate while applying a load of 5.0 g by a thermomechanical analysis (TMA) apparatus. The coefficient of linear expansion was measured from the amount of stretching of the polyimide film with respect to temperature.

[Measurement of Pyrolysis Temperature (Td5%)]

Polyimide film weighing 10 to 20 mg in a nitrogen atmosphere was measured for weight change when the temperature was raised from 30 to 550 ° C. at a constant rate in a thermogravimetric analysis (TG) apparatus, and the 5% weight reduction temperature (Td 5% ) Was obtained.

[Measurement of moisture absorption rate]

The polyimide films (3 pieces each) of 4 cm x 20 cm were dried at 120 ° C for 2 hours, and then left to stand at 23 ° C / 50% RH in a constant temperature and humidity chamber for at least 24 hours. .

Moisture absorption rate (%) = [(weight after moisture-weight after drying) / weight after drying] × 100

[Measurement of Hygroscopic Expansion Coefficient (CHE)]

The etching resist layer was provided on the copper foil of 35 cmx35 cm polyimide / copper laminated body, and this was formed in the pattern which arrange | positions 12 points of 1 mm diameter at 10 cm space | interval on four sides of a 30 cm square. The copper foil exposed part of the etching resist opening part was etched, and the polyimide film for CHE measurement which has 12 copper foil remaining points was obtained. After drying the film at 120 ° C for 2 hours, the film was allowed to stand for at least 24 hours in a constant temperature and humidity chamber at 23 ° C / 50% RH, and the dimensional change between the copper foil points due to humidity was measured by a two-dimensional measuring instrument. Obtained.

[Measurement of dielectric constant]

A film sample of 5 cm × 5 cm was prepared, and the dielectric constant was measured at a frequency of 15 GHz using a microwave molecular alignment system MOA-6015 in a constant temperature and humidity chamber at 23 ° C. and 50% RH.

[Measurement of Adhesive Strength]

The adhesive force was obtained by fixing the resin side of a copper-clad product of width 10mm to an aluminum plate with a double-sided tape using a tensile tester, and peeling copper at a rate of 50 mm / min in the 180 ° direction.

Example

Synthesis Examples 1-14

Polyamic acid A-N used by the Example and the comparative example was synthesize | combined.

Under a nitrogen stream, the diamines shown in Table 1 were dissolved in solvent DMAc 100 g while stirring in 500 ml of a detachable flask. Then, tetracarboxylic dianhydride shown in Table 1 was added. DMAc was added if necessary for viscosity adjustment. Thereafter, the solution was stirred at room temperature for 4 hours to carry out a polymerization reaction to obtain a sulfur to dark brown viscous solution of 14 kinds of polyamic acids A to N serving as polyimide precursors. It was confirmed that the weight average molecular weight (Mw) of each polyamic-acid solution was 100,000 or more, and the polyamic acid of high polymerization degree was produced. Solid content and solution viscosity of polyamic acid are shown in Table 1. Here, solid content is a weight ratio of polyamic acid with respect to the total amount of polyamic acid and a solvent. Solution viscosity was measured using an E-type viscometer.

Examples 1-11

The polyamic acid A-K solution obtained in the synthesis examples 1-11 was apply | coated so that the film thickness after drying might be about 20 micrometers using an applicator on the copper foil of 18 micrometers thickness, respectively, After drying for 60 minutes, heat treatment was carried out stepwise for 2 to 30 minutes at 130 ° C., 160 ° C., 200 ° C., 230 ° C., 280 ° C., 320 ° C., and 360 ° C. to form a polyimide layer on the copper foil. The laminated body of was obtained. The laminated body obtained from the polyamic acid A obtained by the synthesis example 1 is called the laminated body A of Example 1, and it makes it the same below.

Comparative Examples 1 and 2

A laminate was obtained in the same manner as above except that the solution of polyamic acid M obtained in Synthesis Example 13 was used. This laminate is referred to as laminate M of Comparative Example 1. The laminate was obtained in the same manner as above except that the solution of polyamic acid N obtained in Synthesis Example 14 was used. This laminate is referred to as laminate N of Comparative Example 2.

For the laminates of Examples 1 to 11 and Comparative Examples 1 and 2, copper foil was etched away using a ferric chloride solution to prepare 13 kinds of polyimide films A to K and M to N, and the glass potential temperature was obtained. (Tg), storage modulus (E '), thermal expansion coefficient (CTE), 5% weight loss temperature (Td5%), moisture absorption rate and humidity expansion coefficient (CHE), and dielectric constant were measured. The polyimide film obtained by the laminated body A is called polyimide film A, and it makes it the same below.

The measurement results are shown in Table 2.

Example 12

After using the 18-micrometer-thick copper foil and uniformly apply | coating the solution of the polyamic acid L prepared in the synthesis example 12 on this copper foil to thickness of 25 micrometers, it heat-dried at 130 degreeC and removed the solvent. Next, the solution of polyamic acid F prepared in Synthesis Example 6 was uniformly applied to a thickness of 195 μm so as to be laminated thereon, and dried by heating at 70 ° C. to 130 ° C. to remove the solvent. Furthermore, the solution of polyamic acid L prepared in Synthesis Example 12 was uniformly applied to a thickness of 37 μm on the polyamic acid F layer, and dried at 140 ° C. to remove the solvent. Then, it heat-treated and imidated at room temperature over 360 degreeC for about 5 hours, and obtained the laminated body Ml in which the insulating resin layer of about 25 micrometers in total thickness which consists of three polyimide-type resin layers was formed on copper foil. The thickness after drying of the polyamic acid apply | coated on copper foil is about 2.5 micrometers / about 19 micrometers / about 3.5 micrometers in order of L / F / L.

Examples 13-14

In the same manner as in Example 12, the laminates M2 and M3 in which an insulating resin layer having a layer thickness of about 25 µm consisting of three polyimide resin layers were formed on the copper foil. The kind of polyamic acid applied on the copper foil and the thickness after drying were sequentially, and the laminate M2 was L about 2.5 μm / C about 19 μm / L about 3.5 μm, and the laminate M3 was about 2.5 μm / H about 19 μm /. L is about 3.5 µm.

For the laminates of Examples 12 to 14, the curvature was judged visually after standing at 23 ° C. and 50% hr of a constant temperature and humidity chamber for 24 hours or more, but no curvature was found in any of them. Adhesive strength was also measured. Furthermore, copper foil was etched away using the ferric chloride solution, the polyimide film was produced, and the coefficient of thermal expansion (CTE) in the three-layer polyimide layer was measured. The measurement results are shown in Table 3.

Polyimide Stacking Number Configuration Adhesiveness (kN / m) CTE (ppm / ℃) Warpage Example 12 3rd Floor L / F / L 1.4 21 ○ Example 13 3rd Floor L / C / L 1.5 20 ○ Example 14 3rd Floor L / H / L 1.4 22 ○

The polyimide films of Examples 1 to 11 produced from the polyimide precursor solutions of Synthesis Examples 1 to 11 were 450 at a 5% weight reduction temperature (Td5%) of heat resistance required for insulating resin applications such as flexible printed laminates. It was possible to lower the modulus of elasticity and lower the dielectric constant of the present invention while maintaining the degree of C or higher. Moreover, although the polyimide films of Comparative Examples 1-2 made from the polyamic acid of the synthesis examples 13 and 14 had a low moisture absorption rate and a humidity expansion coefficient, they are the characteristic in Examples 1, 3, 8, and 10 compared with these, respectively. It can be confirmed that it keeps or lowers. In addition, it was confirmed that the laminates of Examples 12 to 14 were excellent in physical properties such as heat resistance, adhesiveness, thermal expansion coefficient, and warpage.

Claims (3)

In a laminate having metal foil on one or both sides of the polyimide resin layer, at least one layer of the polyimide resin layer contains 10 mol% or more of the structural unit represented by the following general formula (1). Laminate. [Formula 1]

Here, Ar ₁ is a tetravalent organic group which has one or more aromatic rings, and R is a C2-C6 hydrocarbon group. The laminated polyimide resin layer according to claim 1, wherein the polyimide resin layer has a coefficient of linear expansion of 25 ppm / 占 폚 or lower, a storage modulus at 23 占 폚 of 6 GPa or lower, and a humidity expansion coefficient of 5 ppm /% RH or lower. sieve. The laminate of claim 1, wherein the polyimide resin layer has a dielectric constant of 3.2 or less at 15 GHz.