JPH08294993A - Flexible copper plated laminate board - Google Patents

Abstract

PURPOSE: To improve a heat resistance, a workability, and an adhesiveness by employing a thermoplastic polyimide copolymer having specific repeating units as an intermediate layer interposed between a base film layer and a conductive layer consisting of a good electric conductor. CONSTITUTION: The flexible copper plated laminate board preferably adapted to a method of packaging semiconductor elements or a wiring board for mounting them is formed of a base film, an intermediate layer consisting of thermoplastic polyimide copolymer having a repeating unit A and B represented by the formulae I, II and mole fraction A/B of the repeating units A, B being in the range of 50/50-99/1, and a good electric conductor. In the formulae, R1 represents a bivalent organic group, R2 represents a bivalent aromatic group, and R3 represents a quadrivalent aromatic group. Such thermoplastic polyimide copolymer has a low glass transition temperature, excellent adhesiveness at low temperature, low moisture absorption, and enhances heat resistance or the like of the laminate board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible copper clad laminate, and more specifically, a thermoplastic polyimide copolymer having excellent heat resistance and adhesiveness, particularly low water absorption and low dielectric properties, as an intermediate layer. To a flexible copper clad laminate.

[0002]

2. Description of the Related Art In recent years, electronic devices have become more sophisticated, have higher performance,
The miniaturization is progressing, and the miniaturization and the weight reduction of the electronic components used in association with them are demanded. Therefore, semiconductor device packaging methods and wiring boards for mounting them have also been required to have higher density, higher functionality, and higher performance. FP to meet this demand
Fine line processing of C, multi-layer formation, etc. have come to be performed, and FP
A high-density FPC such as a component mounting FPC in which components are directly mounted on C, a double-sided FPC in which circuits are formed on both sides, or a multi-layer FPC in which a plurality of FPCs are stacked and interconnected between layers has appeared. .

By the way, the FPC basically has a structure in which a circuit pattern is formed on a flexible and thin base film and a cover lay is applied to the surface thereof, in order to obtain the densified FPC as described above. Is required to improve the performance of insulating adhesives and insulating organic films used as the materials. In particular, when it is used as a high-density mounting material such as LOC package or MCM, a printed wiring board material such as multi-layer FPC, or an aerospace material, it has high heat resistance, mechanical strength, workability and adhesiveness. It is required to have excellent properties, particularly low hygroscopicity, and also have various properties such as electrical properties and dimensional stability.

At present, a film made of a polyimide resin as an organic insulating material used as a base film or a coverlay film of FPC has high heat resistance and mechanical strength, and is excellent in electric characteristics. It is preferably used as a film.

However, the polyimide resin is almost infusible and insoluble in the ring-closed state, and there are almost no application examples as an adhesive. As an insulating adhesive used in such applications, low temperature (180 ° C. or less) processability is used. Epoxy resin and acrylic resin are often used because of their excellent workability. However, these adhesives have inferior properties such as heat resistance as compared with polyimide, and for example, high temperature (2
If the temperature is higher than 50 ° C.), the adhesive deteriorates, and there is a problem that the characteristics of the polyimide used as the base film cannot be fully utilized. Furthermore, post-curing for a long time is required, and there is a strong demand for a higher-performance adhesive for the above-mentioned high-density packaging material applications.

Therefore, in order to solve such a problem, an example in which a polyimide-based adhesive is used as an adhesive has recently been proposed. For example, Japanese Patent Laid-Open No. 2-1387
In No. 89, an adhesive film obtained from a resin composition obtained by mixing an aromatic polyimide obtained from 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and an aromatic diamine and a polymaleimide is used, A method of manufacturing an FPC in which a base material such as a film and a copper foil are bonded to each other has been proposed. In addition, JP-A-5-179224 and JP-A-5-11
No. 2768 proposes various thermoplastic polyimide adhesive materials which can be pressure-bonded by heating and pressing.

These polyimide-based adhesives are adhesives having excellent melt flowability, excellent adhesiveness when heated and pressed, and excellent heat resistance. They are polyimide films used as base films for FPCs. It has been attracting attention as an adhesive that can fully exhibit the above characteristics.

[0008]

However, although these polyimide-based adhesives have excellent melt flowability of polyimide and can be used as adhesives, these adhesives require high temperature and long time for adhesion. That is, there is a problem that the bonding cannot be performed unless the temperature is increased to 300 ° C. or higher. Further, there is a problem that these polyimide-based adhesives easily absorb moisture and have poor electrical characteristics after absorbing moisture.

That is, these adhesives easily absorb moisture due to moisture in the air, and have poor electrical characteristics during storage, so that it is difficult to store them in a polyimide state. Therefore, these adhesives cannot be supplied as, for example, a film-like adhesive sheet, and when used as an adhesive, a solution of a polyamic acid which is a precursor thereof is used as a base film or a coverlay film at the time of use. A step of forming an adhesive layer by coating on an insulating film, drying and then heating to imidize was required. Therefore, it is necessary to use FPC with polyimide adhesive.
However, there is a problem that it is difficult to reduce the manufacturing time when manufacturing such products. The process of forming the adhesive layer at the time of use is troublesome, and a method for further simplifying the production of the FPC or the like is required.

Further, in order to manufacture an FPC, after the adhesive layer is formed on the base film in this way, the base film layer on which the adhesive layer is formed and the copper foil or the like are superposed at 300 ° C. or higher. Heat-press to make a copper clad laminate,
After that, a copper foil or the like is etched to form a circuit, and a coverlay film is attached through several steps, but the adhesive layer sometimes absorbs moisture during the manufacturing process of the FPC. As a result, the electrical characteristics of the adhesive layer may be deteriorated, which may cause deterioration of the quality of the final product.

In view of such circumstances, the inventors of the present invention have solved the above-mentioned problems and have a flexible copper clad laminate having an intermediate layer of a high-performance adhesive having various properties required for high-density mounting material applications. As a result of earnestly researching for the purpose of providing a thermoplastic polyimide copolymer having sufficient mechanical strength, excellent heat resistance, processability and adhesiveness, and particularly low water absorption and low dielectric properties. They found a coalescence and reached the present invention.

[0012]

The gist of the flexible copper-clad laminate according to the present invention includes a base film layer and a compound represented by the general formula (1):

[Chemical 6] And the general formula (2) 7

[Chemical 7] (In the formula, R ₁ is a divalent organic group, R ₂ is a divalent aromatic group,
R ₃ represents a tetravalent aromatic group. ) Has the repeating units (A) and (B), and the above repeating unit (A)
(B) Molar fraction ([A] / [B]) in the range of 50/50 to 99/1, composed of an intermediate layer made of a thermoplastic polyimide copolymer, and a conductor layer made of a good electrical conductor. To be done.

In such a flexible copper-clad laminate, the R ₁ group in the general formulas (1) and (2) is

Embedded image In is any of the divalent organic group represented, R ₂ groups of 9

[Chemical 9] In a divalent aromatic group represented, R ₃ groups of 10

[Chemical 10] Is a tetravalent aromatic group represented by.

[0014]

The flexible copper clad laminate according to the present invention will be described below. The flexible copper clad laminate of the present invention comprises a base film layer and a compound represented by the general formula (1).

[Chemical 11] And the general formula (2)

[Chemical 12] (In the formula, R ₁ is a divalent organic group, R ₂ is a divalent aromatic group,
R ₃ represents a tetravalent aromatic group. ) Has the repeating units (A) and (B), and the above repeating unit (A)
It is composed of an intermediate layer which is an adhesive layer composed of a thermoplastic polyimide copolymer having a molar fraction of (B) [(A) / (B)] in the range of 50/50 to 99/1, and an electrically good conductor. And a conductor layer.

Such a thermoplastic polyimide copolymer has a low glass transition temperature, exhibits excellent adhesiveness at low temperatures, has a low water absorption rate, and has excellent dielectric properties, and is used as an adhesive for flexible copper-clad laminates. It can be preferably used, and specifically, it can be obtained by the following method.

That is, in an atmosphere of an inert gas such as argon or nitrogen, the general formula (3) NH ₂ —R ₂ —H ₂ N (3) (in the formula, R ₂ represents a divalent aromatic group) The aromatic diamine represented by is dissolved or diffused in an organic solvent. In this solution, the compound of the general formula (4) 13

[Chemical 13] (Wherein R ₁ represents a divalent organic group) and an aromatic diester dianhydride represented by the general formula (5)

Embedded image An aromatic tetracarboxylic dianhydride represented by the formula (in the formula, R ₃ represents a tetravalent aromatic group) is added in the form of a solution or slurry with a solid or organic solvent. And
-10 to 50 ° C, more preferably -5 to 20 ° C, 30
A polyamic acid copolymer solution, which is a precursor of the thermoplastic polyimide copolymer used in the present invention, can be obtained by reacting for 6 minutes to 6 hours.

In such a reaction, the ratio of the acid dianhydride component can be arbitrarily selected, but the aromatic diester acid dianhydride represented by the general formula (4) and the general formula (5) It is preferable to use it so that the molar ratio of the aromatic tetracarboxylic acid dianhydride represented by (4) is in the range of 50:50 to 99: 1. This is because if the proportion of the aromatic diester dianhydride is smaller than 50%, the processing temperature, that is, the glass transition temperature becomes high, and if it is larger than 99%, the polymer becomes poor in self-supporting property. The aromatic diamine represented by the general formula (3) is preferably used in an equimolar amount to the total amount of the acid dianhydride component.

In the reaction, contrary to the above, first, the acid dianhydride component represented by the general formula (4) and the general formula (5) is dissolved or diffused in an organic solvent,
A solution or slurry of a solid or organic solvent of the aromatic diamine represented by the general formula (3) may be added to the solution.

More specifically, as the aromatic diamine represented by the general formula (3), aromatic diamines having any structure can be used, but R ₂ in the general formula (3) is particularly preferable.
Group is 15

[Chemical 15] It is preferable to use 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) represented by

In the acid dianhydride component, as the aromatic diester dianhydride represented by the general formula (4), aromatic diester dianhydrides having any structure can be used, but in particular, Is an R ₁ group in the general formula (4)

Embedded image 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ', 4,4'-tetracarboxylic dianhydride (ESDA), or 3,3', 4, 4'-ethylene glycol dibenzoate tetracarboxylic dianhydride (E
It is preferred to use either GDA) or 3,3 ′, 4,4′-propylene glycol dibenzoate tetracarboxylic dianhydride (TMPG).

As the aromatic tetracarboxylic acid dianhydride represented by the general formula (5), aromatic tetracarboxylic acid dianhydrides having any structure can be used, and particularly, the general formula (5) The R ₃ group in

[Chemical 17] It is preferable to use 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) represented by

Examples of the organic solvent used in the reaction for producing the aromatic polyamic acid copolymer solution include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, N, N-dimethylformamide, and the like.
Examples thereof include formamide solvents such as N, N-diethylformamide and acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide. These may be used alone or as a mixed solvent of two or three or more. Further, these polar solvents can be used as a mixed solvent with a non-solvent of a polyamic acid copolymer such as acetone, methanol, ethanol, isopropanol and benzenemethylcellosolve.

By such a reaction, the above repeating units (A) and (B), which are used as an adhesive in the present invention and serve as an intermediate layer of the flexible copper-clad laminate of the present invention, are contained in the repeating units (A) and (B). The mole fraction ([A] / [B]) of
Thus, a solution of a polyamic acid copolymer which is a precursor of the thermoplastic polyimide copolymer in the range of 50/50 to 99/1 can be obtained.

Then, this polyamic acid copolymer solution is formed into a film and thermally and / or chemically dehydrated and cyclized (imidized) to form a thermoplastic polyimide which is preferably used as an adhesive in the present invention. A film made of the copolymer can be obtained.

Explaining by way of example, in the method of thermal dehydration ring closure, first, the solution of the polyamic acid copolymer is flowed on a support plate, an organic film such as PET, or a support such as a drum or an endless belt. It is spread or coated to form a film, and dried to obtain a film having self-supporting property. This drying is preferably carried out at a temperature of 150 ° C. or lower for about 5 to 90 minutes. Then, this is further heated and dried to be imidized, and the above repeating units (A) and (B) used in the present invention are used.
A film made of a thermoplastic polyimide copolymer having At the time of heating, it is preferable to peel off this self-supporting film from the support and fix the ends in that state to obtain a film having a small coefficient of thermal expansion. The temperature during heating is preferably in the range of 150 to 350 ° C. There is no limitation on the rate of temperature increase during heating, but it is preferable that the maximum temperature reaches the above temperature by gradually heating. The heating time varies depending on the film thickness and the maximum temperature, but in general, it is preferably in the range of 10 seconds to 5 minutes after the maximum temperature is reached.

In the method of chemically dehydrating and ring-closing, the same method as in the case of thermally dehydrating by adding a stoichiometric or more stoichiometric dehydrating agent and a catalytic amount of a tertiary amine to the solution of the polyamic acid copolymer is used. When treated by the method, the desired polyimide film can be obtained in a shorter time than when thermally dehydrated.

Comparing the thermal imidization method and the chemical imidization method, the chemical method has the advantage that the obtained polyimide film has a large mechanical strength and a small thermal expansion coefficient. is there. In addition, it is also possible to use the method of thermally imidizing and the method of chemically imidizing together.

The molecular weights of the polyamic acid copolymer and the polyimide copolymer are not particularly limited, but in order to maintain the strength of the obtained film, the number average molecular weight is 50,000 or more, and further, It is preferably 80,000 or more, particularly 100,000 or more, and more preferably 120,000 or more. However,
In many cases, it is difficult to directly measure the molecular weight of the polyimide copolymer, and in such a case, an indirect method is used to estimate the molecular weight. For example, when the polyimide copolymer is synthesized from the polyamic acid copolymer, the value corresponding to the molecular weight of the polyamic acid is the molecular weight of the polyimide copolymer.

By such a method, the molar fraction [(A) / (B)] of the repeating units (A) and (B) represented by the above general formulas (1) and (2) is 50/50 to 99. A film made of a thermoplastic polyimide copolymer in the range of / 1 is obtained. The thermoplastic polyimide copolymer film has excellent thermoplasticity, heat resistance, low-temperature adhesiveness, low water absorption, and low dielectric properties, and has the intermediate properties of the flexible copper-clad laminate of the present invention. It can be preferably used as a layer.

That is, the above-mentioned thermoplastic polyimide copolymer has excellent heat resistance which is a characteristic of polyimide, has a clear glass transition temperature between 100 and 250 ° C. depending on its composition, and has a glass transition temperature higher than the glass transition temperature. Excellent adhesion is obtained by laminating at temperature. Further, these copolymers show a low water absorption rate of 1% or less when immersed in pure water at 20 ° C. for 24 hours, and also have a dielectric constant of 1
It has a low dielectric constant of 3.0 or less at MHz (normal state).

Then, the film made of the thermoplastic polyimide copolymer is inserted as an adhesive between the base film and the conductor layer such as a copper foil, and the films are superposed in three layers and thermocompression-bonded. A flexible copper clad laminate can be obtained.

The base film referred to in the present invention is FP.
Any film may be used as long as it can be used as a base film such as C, but a polyimide film having excellent heat resistance is particularly preferably used. Specifically, as the polyimide film used as the base film, for example, a polyimide film having no adhesiveness such as "Apical (registered trademark; manufactured by Kaneka Kagaku Kogyo Co., Ltd.)" can be used, and any other structure can be used. It may be a polyimide film.

As another method for obtaining the flexible copper-clad laminate of the present invention, a film adhesive made of the polyimide copolymer is laminated on both sides or one side of the base film and thermocompression bonded to produce a bonding sheet. After that, copper foil may be overlapped on both sides or one side thereof and thermocompression bonded.

In addition, a solution of the polyamic acid copolymer, which is the precursor of the polyimide copolymer, is cast and applied on both sides or one side of the base film to imidize it, and then copper foil is laminated on both sides or one side. The manufacturing method is not limited, such that it can be obtained by thermocompression bonding.

The flexible copper-clad laminate according to the present invention thus obtained has the base film and the conductor layer firmly bonded to each other by the intermediate layer composed of the thermoplastic polyimide copolymer, and serves as an insulating adhesive. It exhibits excellent heat resistance as compared with the case of using an epoxy resin or an acrylic resin, and no deterioration of the adhesive layer is observed even at a high temperature of 250 ° C. or higher. The above-mentioned thermoplastic polyimide copolymer used as the intermediate layer in the present invention has a glass transition temperature of 1
The temperature is from 0 to 250 ° C., which shows excellent adhesiveness by thermocompression bonding at a relatively low temperature for a short time as compared with a conventionally known polyimide adhesive, and a flexible copper clad laminate can be obtained very easily.

Further, in such a flexible copper-clad laminate, the base film and the intermediate layer are both made of a polyimide film, and in the case of producing an FPC or the like, for example, copper foil can be etched and then punched by alkali etching. The FPC can be manufactured relatively easily.

Furthermore, conventionally known polyimide adhesives are difficult to store in the state of polyimide due to their high water absorption, and flexible copper clad laminates using conventional polyimide adhesives are intermediate. The layer may absorb moisture during storage, or may absorb moisture during the FPC manufacturing process such as etching. On the other hand, since the thermoplastic polyimide copolymer used as the intermediate layer in the present invention exhibits a low water absorption rate as described above, the flexible copper-clad laminate of the present invention has the intermediate layer absorbing moisture as in the conventional case. There is nothing to do. Therefore, in the case of producing an FPC, it is not necessary to perform the step of forming the adhesive layer during the production of the FPC as in the conventional case, and the flexible copper-clad laminate of the present invention is produced in advance, thereby Can be further simplified.

Although the embodiments of the flexible copper-clad laminate according to the present invention have been described above, the present invention is not limited to these embodiments, and the present invention is applicable within the scope of the invention. The present invention can be implemented with various improvements, changes and modifications based on the knowledge of those skilled in the art.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. In the examples, DMF is N, N-dimethylformamide. Also, BAPP is 2,2-bis [4-
(4-aminophenoxy) phenyl] propane, and E
SDA is 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ', 4,4'-tetracarboxylic dianhydride,
BTDA is 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, EGDA is 3,3', 4,4'-ethylene glycol dibenzoate tetracarboxylic dianhydride, TMPG is 3,
It is 3 ', 4,4'-propylene glycol dibenzoate tetracarboxylic dianhydride.

Examples 1 to 3 A 500 ml three-neck separable flask (1) equipped with a stirrer was charged with 16.4 g (40 mmol) of BAPP and the amount of DMF shown in Table 1 and stirred under a nitrogen atmosphere to sufficiently dissolve them. Next, BTDA and ESDA were sampled in a 50 ml eggplant flask (2) at the ratio shown in Table 1, and B of the separable flask (1) was collected.
It was added as solid in the APP solution. The wall surface of the eggplant flask (2) was washed with 5 g of DMF and separated into a separable flask.
(1) It poured into the inside. After standing for about 1 hour while stirring, pay attention to the viscosity of the varnish in the separable flask (1) in a solution of 0.6 g of ESDA dissolved in 5.0 g of DMF in advance. While gradually throwing in. After reaching the maximum viscosity, the addition of the ESDA solution was terminated to obtain a polyamic acid solution.

[0041]

[Table 1]

The film formation was performed as follows. First, 10
Isoquinoline (10.0 g), acetic anhydride (10.0 g) and DMF (10.0 g) were placed in a 0 ml volumetric flask (3) and well stirred. Next, to 100 g of the prepared polyamic acid solution,
The solution in the volumetric flask (3) was added and well stirred for 2 minutes. After degassing, apply on PET film and apply at 80 ℃
After peeling off the PET film by heating for 25 minutes, the end is fixed and the temperature is continuously raised from 100 ° C. to 250 ° C., and after the temperature is raised, it is heated for 5 minutes to be imidized. A polyimide film was obtained.

Then, the thermoplastic polyimide adhesive film obtained above is laminated on both sides of the polyimide film, and copper foil (35 μm) is further laminated on both sides thereof, and the temperature is 240 ° C., 20 kg /
The flexible copper clad laminate of the present invention was obtained by hot pressing for 10 minutes under the condition of cm ² .

The glass transition point (° C.), water absorption rate (%) and dielectric constant of the obtained polyimide film were measured, and the peel strength (kg / cm) was measured using the obtained flexible copper clad laminate. did. TMA for glass transition point
The water absorption is measured according to ASTM D-570.
Measure the rate of weight change after immersion in pure water at 20 ° C according to
Was measured by Regarding peel strength, JIS
It measured according to K6471. Table 2 shows the results.

[0045]

[Table 2]

Comparative Example 1 For comparison, a polyamic acid solution was obtained in substantially the same manner as in Example 1 except that ESDA was not used, and a thermoplastic polyimide film of BTDA and BAPP having a thickness of 25 μm was prepared. To obtain a flexible copper clad laminate. The amount of the reagent for obtaining the polyamic acid solution is as shown in Table 1, and the last was 0.6 g of BT in advance.
A solution prepared by dissolving DA in 8.0 g of DMF was gradually added while paying attention to the varnish clay in the flask. And about the obtained thermoplastic polyimide film, Example 1
The glass transition point (° C.), water absorption rate (%) and dielectric constant were measured in the same manner as in, and the peel strength (kg / cm) was measured using a flexible copper clad laminate. The results are shown in Table 2.

Comparative Example 2 For comparison, a polyamic acid solution was obtained in substantially the same manner as in Example 1 except that the proportion of ESDA was reduced.
A thermoplastic polyimide film having a thickness of 5 μm was obtained, and a flexible copper-clad laminate was further obtained. The amounts of reagents for obtaining the polyamic acid solution are as shown in Table 1. Then, the glass transition point (° C.), water absorption rate (%) and dielectric constant of the obtained polyimide film were measured in the same manner as in Example 1, and the peel strength (kg / kg / cm) was measured. The results are shown in Table 2.

Examples 4 to 6 Polyamide acid solutions were obtained in substantially the same manner as in Examples 1 to 3 except that EGDA was used in place of ESDA in Examples 1 to 3, and each of them was heated to a thickness of 25 μm. A plastic polyimide film was obtained, and then a flexible copper clad laminate of the present invention was obtained. The amounts of reagents for obtaining the polyamic acid solution are as shown in Table 1. Then, the glass transition point (° C.), water absorption rate (%) and dielectric constant of the obtained polyimide film were measured in the same manner as in Example 1, and the peel strength (kg / kg / c
m) was measured. Table 3 shows the results.

[0049]

[Table 3]

Comparative Example 3 For comparison, a polyamic acid solution was obtained in substantially the same manner as in Examples 4 to 6 except that the proportion of EGDA was reduced to obtain a 25 μm thick thermoplastic polyimide film.
Further, a flexible copper clad laminate was obtained. The amounts of reagents for obtaining the polyamic acid solution are as shown in Table 1. The glass transition point (° C.), water absorption rate (%) and dielectric constant of the obtained polyimide film were measured in the same manner as in Example 1, and the peel strength (kg / cm) was measured using a flexible copper clad laminate. ) Was measured. The results are shown in Table 3 together with the results of Comparative Example 1.

Examples 7 to 9 Polyamide acid solutions were obtained in substantially the same manner as in Examples 1 to 3 except that TMPG was used in place of ESDA in Examples 1 to 3, and each of them was heated to a thickness of 25 μm. A plastic polyimide film was obtained, and then a flexible copper clad laminate of the present invention was obtained. The amounts of reagents for obtaining the polyamic acid solution are as shown in Table 1. Then, the glass transition point (° C.), water absorption rate (%) and dielectric constant of the obtained polyimide film were measured in the same manner as in Example 1, and the peel strength (kg / kg / c
m) was measured. The results are shown in Table 4.

[0052]

[Table 4]

Comparative Example 4 For comparison, a polyamic acid solution was obtained in substantially the same manner as in Examples 7 to 9 except that the proportion of TMPG was reduced in Examples 7 to 9 to obtain a thermoplastic polyimide having a thickness of 25 μm. A film was obtained, and a flexible copper clad laminate was further obtained. The amounts of reagents for obtaining the polyamic acid solution are as shown in Table 1. Then, for the obtained polyimide film, the glass transition point (° C.) was measured in the same manner as in Example 1.
The water absorption (%) and the dielectric constant were measured, and the peel strength (kg / cm) was measured using a flexible copper clad laminate.
The results are shown in Table 4 together with the results of Comparative Example 1.

From Tables 2 to 4, BAP was used as the diamine component.
Using P, ESDA (or EGD as an acid dianhydride component)
A or TMPG) and BTDA are mixed, and the molar ratio of the acid dianhydride component ([ESDA (or EGDA, or TM
It can be seen that the thermoplastic polyimide film obtained by using PG)]: [BTDA]) at 50:50 to 99: 1 has a low glass transition temperature, low water absorption and low dielectric constant.

[0055]

As described above, the flexible copper clad laminate of the present invention comprises the base film layer and the repeating units (A) and (B) represented by the general formulas (1) and (2). Of a thermoplastic polyimide copolymer having a molar fraction [(A) / (B)] of 50/50 to 99/1 and a conductor layer made of a good electrical conductor. Since this thermoplastic polyimide copolymer exhibits low water absorption, it can be supplied as the flexible copper-clad laminate of the present invention. Further, such a flexible copper-clad laminate can provide a high-quality product without the intermediate layer absorbing moisture in the conventional storage or in the FPC manufacturing process, even though the intermediate layer is polyimide. It is a thing.

Further, such a thermoplastic polyimide copolymer has a low glass transition temperature and exhibits excellent adhesiveness when laminated at a temperature higher than that near the glass transition temperature. Furthermore, it has excellent heat resistance, retains its excellent adhesiveness even at high temperatures, and also has excellent properties such as low dielectric properties, making it an adhesive for flexible copper-clad laminates. It is suitable. That is,
The flexible copper clad laminate of the present invention is suitable for use as a high-density mounting material such as LOC package and MCM, a printed wiring board material such as multilayer FPC, and an aerospace material because of its excellent characteristics.

Since the flexible copper-clad laminate of the present invention has the adhesive layer made of polyimide, both the base film and the adhesive layer can be made of polyimide, and the obtained copper-clad laminate is etched. After processing to form the wiring pattern, the polyimide can be further subjected to hole processing by alkali etching, and a double-sided FPC can be manufactured relatively easily. Similarly, it can be preferably used as a multilayer FPC material, and is also suitable for other uses such as a rigid flex substrate material.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H05K 1/03 670 7511-4E H05K 1/03 670A

Claims (2)

[Claims] 1. A base film layer and a compound represented by the general formula (1): And the general formula (2): (In the formula, R ₁ is a divalent organic group, R ₂ is a divalent aromatic group,
R ₃ represents a tetravalent aromatic group. ) Has the repeating units (A) and (B), and the above repeating unit (A)
(B) Molar fraction ([A] / [B]) in the range of 50/50 to 99/1, composed of an intermediate layer made of a thermoplastic polyimide copolymer, and a conductor layer made of a good electrical conductor. A flexible copper-clad laminate characterized by being formed. 2. The R ₁ group in the general formula (1) and the general formula (2) is represented by the following formula: In is any of the divalent organic group represented, R ₂ groups of 4 ## STR4 ## In a divalent aromatic group represented, R ₃ groups of 5 embedded image The flexible copper-clad laminate according to claim 1, which is a tetravalent aromatic group represented by: