KR101170201B1 - Laminate for wiring board - Google Patents

Abstract

Wiring with aromatic polyimide resin layer having excellent heat resistance, thermal dimensional stability, moderate elastic modulus, and low hygroscopicity, low humidity expansion coefficient, and low dielectric constant while suppressing warpage due to humidity without accompanying various problems originating from the adhesive layer. It relates to a laminate for substrates.

This laminated board for wiring boards is a laminated body which has metal foil in the single side | surface or both surfaces of a polyimide resin layer, and at least one layer of the said polyimide resin layer contains 10 mol% or more of structural units represented by following General formula (1). do.

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.

Thermal Dimensional Stability, Flexure, Elastic Modulus, Heat Resistance, Laminates for Wiring Boards, Metal Foil

Description

Laminated body for wiring board {LAMINATE FOR WIRING BOARD}

TECHNICAL FIELD This invention relates to the laminated body for wiring boards used for a flexible printed wiring board, HDD suspension, etc.

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

Generally, the film which consists of polyimide resin excellent in various characteristics is widely used for the insulation film of FPC, The epoxy resin and acrylic resin which are excellent in low temperature processability are used for the insulation adhesive layer between an insulation film and a 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, the method of coating and forming a polyimide resin layer directly on metal foil has been employ | adopted in recent years without forming an adhesive layer. Patent Document 1 discloses a method of providing an FPC having excellent adhesive strength and thermal dimensional stability by multilayering a polyimide resin layer with a plurality of polyimides having different thermal expansion coefficients. However, since these polyimides have high hygroscopicity, problems such as expansion when immersed in a solder bath and poor connection due to dimensional change after moisture absorption during thin wire processing are caused, and in general, metals used in conductors have humidity. Since the expansion coefficient was close to zero or zero, the dimensional change after moisture absorption was also a cause of the defects such as bending, curling, and twisting of the laminate.

As a prior document related to this invention, there exist the following documents.

Patent Document 1: Japanese Patent Application Laid-open No. Hei 2-225522

Patent Document 2: Japanese Patent Application Laid-Open No. 2001-11177

Patent Document 3: Japanese Patent Application Laid-open No. Hei 8-217877

Patent Document 4: Japanese Patent Application Laid-Open No. 2000-63543

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

Patent Document 6: WO01 / 28767A1

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 drawbacks include an increase in manufacturing cost or poor adhesion to metal materials. have. 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 maintained.

In addition, the polyimide has a structure in which a tetracarboxylic dianhydride component and a diamine component are alternately bonded, but a polyimide using diaminobiphenyl or diaminobiphenyls in which methoxy is substituted as diamine is disclosed in Patent Document 2 Although illustrated in, the specific example is not shown and it cannot predict what kind of characteristics they have.

Moreover, in patent documents 5-6, the monomer which provides high heat resistance, a high elastic modulus, and low hygroscopic 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 applied to such a use, the moderate elasticity modulus which is not too rigid is calculated | required, and the balance with the other physical 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 polyimides contain a strong imide group, most have a dielectric constant of 3.5 or more, and development of lower dielectric constant materials has been desired.

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, and moderate elastic modulus, and has realized low hygroscopicity, low humidity expansion coefficient and low dielectric property. It aims to provide.

That is, this invention is a laminated body which has metal foil in the single side | surface or both surfaces of a polyimide resin layer, WHEREIN: At least 1 layer of the said polyimide resin layer contains 10 mol% or more of structural units represented by 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 layer or a multilayer polyimide resin layer. As metal foil, the copper foil of 10-50 micrometers in thickness is suitable for using for a flexible printed wiring board use, and when using as a board | substrate for HDD suspension, the stainless steel foil of 10-70 micrometers in thickness is suitable. At least 1 layer of the said polyimide resin layer contains 10 mol% or more of structural units represented by the said 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 from this is also called this polyimide resin layer or this polyamic acid layer.

In the structural unit represented by the general formula _(1), Ar 1 is a tetravalent organic group having at least one aromatic ring, may be referred to as aromatic tetracarboxylic acid or the acid is an aromatic tetracarboxylic acid residue resulting from such anhydrides . Therefore, Ar ₁ is understood by explaining the aromatic tetracarboxylic acid to be used. Typically, the described case to synthesize a polyimide or a polyamic acid having the structural unit, since the aromatic tetracarboxylic a multitude of being 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'-benzophenone tetracarboxylic dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic dianhydride, 2,3 , 3 ', 4'-benzophenonetetracarboxylic 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-hexa Hydronaphthalene-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-tetracarboxylic acid dianhydride Water, 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-tetracarbon Dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7-tetracar Dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarb Dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride Can be 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 a suitable quantity 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 a suitable thing so as to express the characteristics necessary for the purpose of use, such as the thermal expansion coefficient, thermal decomposition temperature, and glass transition temperature of the polyimide obtained by superposition | polymerization heating.

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 can be 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%, further preferably at least one layer of the polyimide resin layer. It is good to include 90 to 100 mol%.

As the diamine used for copolymerization other than the aromatic diamine represented by General formula (2), although it does not specifically limit, 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'-diaminodiphenyl ether, 3,3-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophen 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-aminophen Til) 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 all 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 above reaction is applied onto an adhesive layer formed on a metal foil or a metal foil serving as a support using an applicator, and imidated by a thermal imidization method or a chemical imidization method to provide the wiring of the present invention. The laminated body for board | substrates is obtained. Thermal imidation is performed by pre-drying for 2 to 60 minutes at the temperature of 150 degrees C or less, and heat-processing normally for about 2 to 30 minutes at the temperature of about 130-360 degreeC. 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 copper foil thickness 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, after repeating the operation of applying and drying a polyamic acid solution, heat treatment is performed to remove the solvent, and heat treatment is carried out at a higher temperature to imidize the polyimide resin layer having a multilayer structure. Can be formed. 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 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 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 transition temperature of the polyimide resin used. In addition, about hot press pressure, although it depends on the kind of press apparatus to be used, it is preferable that it is the range of 1-500 kg / cm <^2> . Moreover, the same thing as said metal foil can be used for the preferable metal foil used at this time, 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 used for the various combination 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 lower and a storage modulus at 23 ° C. of 6 GPa or lower, and a humidity expansion coefficient of 5 ppm /% RH or lower, and from the viewpoint of heat resistance, at the glass transition temperature. Pyrolysis temperature (Td5%) which is 350 degreeC or more and 5% weight loss temperature in a thermogravimetric analysis is 450 degreeC or more. Moreover, the dielectric constant in 15GHz of the preferable polyimide resin layer which comprises the laminated body for wiring boards of this invention 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 an overall numerical value.

The wiring board laminate of the present invention has a polyimide resin layer, and thus the polyimide resin layer serving as the insulating layer has excellent heat resistance, low moisture absorption and low dielectric properties, and excellent dimensional stability. It also has the effect of suppressing the warpage caused by humidity. 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, the polyimide resin layer is characterized in that it is not anisotropic in plane and can be widely applied to parts 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 Transition Temperature (Tg), Storage Modulus (E ')]

The polyimide film (10 mm x 22.6 mm) obtained in each example was measured by dynamic thermomechanical analysis device (DMA) to measure the dynamic viscoelasticity when the temperature was raised from 20 ° C to 500 ° C at 5 ° C / min. 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%)]

5% weight reduction temperature (Td5%) by measuring the weight change when a polyimide film weighing 10-20 mg was heated in a nitrogen atmosphere at a constant rate using a thermogravimetric analysis (TG) device at a constant rate from 30 ° C to 550 ° C. ) Was obtained.

[Measurement of moisture absorption rate]

After drying 4 cm x 20 cm of polyimide films (3 pieces each) at 120 degreeC for 2 hours, they were left to stand in 23 degreeC / 50% RH constant-temperature humidity chamber for 24 hours or more, and the following formula was changed from the weight change before and after that. Obtained by

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 12 points of 1 mm diameter are arrange | positioned at four sides of a 30 cm square at 10 cm intervals. 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 copper foil points due to humidity was measured by a two-dimensional measuring instrument. , The coefficient of humidity expansion was 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 type molecular orientation meter MOA-6015 in a constant temperature and humidity chamber at 23 ° C. and 50% RH.

[Measurement of Adhesive Strength]

Adhesive force is fixed by tension tester, fixing the resin side of copper-clad product of 10mm width to aluminum plate with double-sided tape, and peeling copper at 50mm / min in 180 ° direction. It was.

Example

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

A laminated body 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. A laminated body 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, 13 types of polyimide films A to K and M to N were prepared by etching and removing copper foil using an aqueous ferric chloride solution. (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.

Table 2 shows the measurement results.

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 the 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 the polyamic acid L prepared in the synthesis example 12 on the polyamic acid F layer was apply | coated uniformly to thickness of 37 micrometers, and it dried by heating at 140 degreeC, and removed the solvent. Then, it heat-treated and imidated at room temperature over 360 degreeC for about 5 hours, and obtained the laminated body M1 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, 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 copper foil were obtained. The kind of polyamic acid applied on the copper foil and the thickness after drying were, in order, the laminate M2 was L about 2.5 μm / C about 19 μm / L about 3.5 μm, and the laminate M3 was L about 2.5 μm / H about 19 μm. / L is about 3.5 mu m.

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

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, which are generated from the polyimide precursor solutions of Synthesis Examples 1 to 11, are 450 ° C or higher at a heat resistance required for insulating resin applications such as flexible printed laminates, that is, 5% by weight reduction temperature (Td 5%). It was possible to lower the modulus of elasticity for the purpose of the present invention and lower the dielectric constant while maintaining. In addition, although the polyimide films of Comparative Examples 1-2 produced in 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 a 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). For laminates. [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 less, a storage modulus at 23 占 폚 of 6 GPa or less, and a humidity expansion coefficient of 5 ppm /% RH or less. sieve. 2. The laminate for wiring boards according to claim 1, wherein said polyimide resin layer has a dielectric constant of 3.2 or less at 15 GHz.