JP4722169B2 - Polyimide metal laminate - Google Patents

Description

  The present invention relates to a polyimide metal laminate for Chip on Film (hereinafter abbreviated as COF) widely used in TAB tape processing lines. More specifically, the present invention relates to a polyimide metal laminate suitable for a COF base material, which has good copper wiring image recognition at the time of chip mounting using an inner lead bonder after circuit processing.

  Conventionally, as a COF base material, a polyimide metal laminate obtained mainly by sputtering metal on a polyimide film has been used. However, in the case of the sputtering method, the yield is likely to deteriorate due to pinholes in the metal layer, and a polyimide metal laminate without pinholes has been desired.

  As a polyimide metal laminated board without a pinhole, there exists a flexible circuit board which laminated | stacked the rolled copper foil or the electrolytic copper foil, and the polyimide. Since the surface shape of the surface of the metal foil on the side where the polyimide is laminated is transferred to the polyimide, the flexible circuit board is metal through the film from the side where the polyimide metal foil is not laminated when the surface shape of the metal foil is rough. There was a problem that it was difficult to see the wiring due to diffuse reflection of light.

  In addition, since the TAB line adopting chip mounting by the flip chip bonder recognizes the image of the metal wiring position from the metal wiring side when positioning the chip and the metal wiring, it can be positioned. However, in a TAB line that uses an inner lead bonder that is not a flip chip type, wiring is performed via a polyimide layer from the opposite side of the polyimide layer metal foil when the chip is mounted after circuit processing. Since the position is image-recognized, image recognition is difficult when the roughness of the metal foil is rough. In order to improve the image recognition, when a polyimide metal laminate is formed and then the metal foil is completely etched and the light transmittance is measured, light having a wavelength of 600 nm is 55% or more, preferably 60% or more. Permeation is desired to improve image recognition.

  The present invention provides a polyimide metal laminate in which a thermoplastic polyimide layer is formed on one surface of one or more non-thermoplastic polyimide layers, and a metal is laminated on the surface of the thermoplastic polyimide layer. When the measurement surface is assumed to be smooth, the value divided by the area is 1.0018 or less. By laminating polyimide on the metal foil, the opposite side where the metal foil was laminated after circuit processing It was found that the circuit can be image-recognized through the polyimide film from the surface, that is, when the metal foil is completely etched and the light transmission is measured, light having a wavelength of 600 nm can be transmitted by 55% or more. completed.

  That is, the present invention is a polyimide metal laminate in which a thermoplastic polyimide layer is formed on one surface of one or more non-thermoplastic polyimide layers, and a metal is laminated on the surface of the thermoplastic polyimide layer. Surface area ratio of the metal surface to be bonded to the thermoplastic polyimide (value obtained by dividing the actual surface area by the area when the measurement surface is assumed to be smooth) The present invention relates to a metal laminated plate characterized by having a value of 1.0018 or less.

  According to the present invention, a polyimide metal laminate having an excellent light transmittance of a polyimide layer, in which circuit positioning is possible with an inner lead bonder that is not a flip chip method, that is, metal wiring can be recognized through a polyimide layer. Can be provided.

The present invention is described in detail below.
The polyimide metal laminate referred to in the present invention is obtained by applying a thermoplastic polyimide or a varnish containing polyamic acid which is a precursor of the thermoplastic polyimide on one surface of a non-thermoplastic polyimide layer, drying and curing the thermoplastic polyimide layer. It is formed by thermocompression bonding the surface of the metal foil having a specific surface shape to the surface of the thermoplastic polyimide layer.

  Specific examples of the metal used in the present invention include copper and copper alloys, stainless steel and alloys thereof, nickel and nickel alloys (including 42 alloys), aluminum and aluminum alloys, and the like. Copper and copper alloy are preferable.

  Moreover, the metal surface shape of the surface joined to the thermoplastic polyimide layer has a great influence on the performance of the polyimide metal laminate. The metal used in the present invention is one in which the surface of the metal bonded to the thermoplastic polyimide is not roughened, but the surface of the metal is not roughened. Even if the maximum surface roughness is small, if the surface unevenness density is large, it may be difficult to recognize the image of the copper wiring after circuit processing at the time of chip mounting.

  In the present invention, from this point of view, the surface shape of the metal to be bonded to the thermoplastic polyimide layer is obtained by dividing the actual surface area by the area when the measurement surface is assumed to be smooth (hereinafter referred to as the surface area ratio). It is important to select and use a metal having a surface area ratio of 1.0018 or less.

  Further, the thickness of the metal is not limited as long as it can be used in the form of a tape, but preferably 2 to 150 μm. Examples of commercially available metal foils that can be used include Furukawa Circuit Foil Co., Ltd., trade name: F0-WS (electrolytic copper foil), and Mitsui Metal Mining Co., Ltd. VLP foil (non-roughened copper foil). Is mentioned.

  As the thermoplastic polyimide forming the thermoplastic polyimide layer, a composition synthesized from a specific diamine and a specific tetracarboxylic dianhydride can be used. Specific diamines include 1,3-bis (3-aminophenoxy) benzene (hereinafter abbreviated as APB), 4,4-bis (3-aminophenoxy) biphenyl (hereinafter abbreviated as m-BP), and 3, At least one diamine selected from 3′-diammibenzophenone (hereinafter abbreviated as DABP) is preferred.

  Specific tetracarboxylic dianhydrides include 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride (hereinafter abbreviated as ODPA), 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride. Selected from anhydride (hereinafter abbreviated as BTDA), pyromellitic dianhydride (hereinafter abbreviated as PMDA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter abbreviated as BPDA) At least one tetracarboxylic dianhydride is preferred.

  In other words, the thermoplastic polyimide of the present invention comprises at least one diamine component selected from the diamine group consisting of APB, m-BP and DABP, and at least one tetra selected from the group consisting of ODPA, BTDA, PMDA and BPDA. It is preferable to use a polycondensation polymer obtained using a carboxylic dianhydride component. The reaction molar ratio of the diamine component and tetracarboxylic dianhydride is usually in the range of 0.75 to 1.25.

As the non-thermoplastic polyimide forming the non-thermoplastic polyimide layer, a composition synthesized from a specific diamine and a specific tetracarboxylic dianhydride can be used. As specific diamines, o- phenylenediamine, p- phenylenediamine, m- phenylenediamine, 4,4'-diamino-di phenyl ether, 3,4-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'- Diaminodiphenyl ether is mentioned. These may be used alone or in combination of two or more. Moreover, when using the said amine compound together, the usage-amount of a specific diamine component is at least 70 mol% or more, Preferably it is 80 mol% or more.

  Specific tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid, etc. Is mentioned. These may be used alone or in combination of two or more.

  Moreover, a commercially available non-thermoplastic polyimide film can be used as the non-thermoplastic polyimide. Examples of commercially available non-thermoplastic polyimide films that can be used include Upilex S, Upilex SGA, Upilex SN (manufactured by Ube Industries, Ltd., trade name), Kapton H, Kapton V, Kapton EN (manufactured by Toray DuPont, Product name), Apical AH, Apical NPI, Apical HP (trade name, manufactured by Kaneka Chemical Co., Ltd.). The surface of the non-thermoplastic polyimide may be subjected to plasma treatment, corona discharge treatment or the like.

  The thickness of the thermoplastic polyimide layer is selected depending on the purpose and is not limited, but a range of 0.5 to 10 μm is preferable. The thickness of the non-thermoplastic polyimide layer is not limited depending on the purpose, but a range of 5 to 250 μm can be suitably used.

  Furthermore, you may laminate | stack non-thermoplastic polyimide on the side which does not laminate | stack a thermoplastic polyimide layer of a commercially available non-thermoplastic polyimide film.

  The polyimide metal laminate provided by the present invention can recognize a metal wiring image from the surface on which the metal of the polyimide layer is not laminated after circuit processing, and can be positioned during chip mounting with an inner lead bonder.

Hereinafter, the present invention will be described in more detail with reference to examples.
In addition, about the surface area ratio of the metal shown in the Example, and copper wiring recognizability, it measured by the following method.
(1) Surface area ratio The surface shape of the sample is measured by Nanopics (contact type surface shape measuring device) manufactured by Seiko Instruments Inc., and the actual surface area is divided by the area when the measurement surface is assumed to be smooth. The surface area ratio was calculated.
(2) Light transmittance (%)
Using a sample obtained by etching and removing the metal with a ferric oxide hydrochloric acid solution maintained at a liquid temperature of 40 ° C., washing and drying, and using a light transmittance measuring device (UV-Vis-NIR manufactured by JASCO Corporation), Light having a wavelength of 200 nm to 850 nm is transmitted through the sample, and linearly transmitted light is observed among the transmitted light. Thereafter, the light transmittance at 600 nm is obtained.

Abbreviations for the solvents, acid dianhydrides, and diamines used in the examples are as follows.
DMAc: N, N-dimethylacetamide NMP: N-methyl-2-pyrrolidone APB: 1,3-bis (3-aminophenoxy) benzene BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride PPD: p-phenylenediamine ODA: 4,4′-diaminodiphenyl ether m-BP: 4,4′-bis (3-aminophenoxy) biphenyl PMDA: pyromellitic dianhydride BPDA: 3, 3 ′, 4, 4 '-Biphenyltetracarboxylic dianhydride

Synthesis example 1
<Synthesis of thermoplastic polyimide resin precursor>
To a container equipped with a stirrer and a nitrogen introduction tube, DMAc 1718.6 g was added as a solvent, 146.2 g of APB was added thereto, and the mixture was stirred at room temperature until dissolved. Thereafter, 157.1 g of BTDA was added and stirred at 60 ° C. to obtain a polyamic acid solution. The obtained polyamic acid solution had a polyamic acid content of 15% by weight and an E-type viscosity at 25 ° C. of 0.5 Pa · s.

Synthesis example 2
<Synthesis of precursor of non-thermoplastic polyimide resin>
To a container equipped with a stirrer and a nitrogen introducing tube, 846.9 g of DMAc and 362.9 g of NMP were added as solvents, and 16.2 g (30 mol%) of PPD and 49.1 g (49 mol%) of ODA were added thereto. Heated to ~ 60 ° C to dissolve. Then, after cooling to about 30 ° C. with ice, 25.1 g of BPDA was added, heated to 60 ° C. and stirred for about 2 hours. Furthermore, m-BP 38.7g (21mol%) was added, and it stirred, keeping temperature at 60 degreeC. Finally, 84.4 g of PMDA was added and stirred at 60 ° C. for 2 hours to obtain a polyamic acid solution. The resulting polyamic acid solution had a polyamic acid content of 15% by weight and an E-type viscosity at 25 ° C. of 0.4 Pa · s.

Example 1
Using a commercially available polyimide resin film (trade name: Kapton 100EN, manufactured by Toray DuPont Co., Ltd.), the thickness of the polyamic acid solution of Synthesis Example 1 (hereinafter referred to as varnish) is dried on a first surface by a roll coater. After coating to 4 μm and drying at 150 ° C. for 2 minutes, the varnish of Synthesis Example 2 was applied to the second surface by a roll coater so that the thickness after drying was 5 μm, and at 70 ° C. for 5 minutes, 110 After drying for 5 minutes at 140 ° C., 2 minutes at 140 ° C., 5 minutes at 180 ° C., 2 minutes at 265 ° C., drying in an air float type drying furnace, the insulating film whose first surface is a thermoplastic polyimide resin layer Got.
Thereafter, commercially available copper foil (Furukawa Circuit Foil Co., Ltd., trade name: F0-WS (thickness 9 μm or 12 μm), or Mitsui Mining Co., Ltd., VLP foil, copper foil without roughening (thickness 12 μm) ) And a roll laminator at 240 ° C. under a pressure of 1.5 MPa, the metal foil and the insulating film are laminated, and then annealed in a batch-type autoclave at a temperature of 280 ° C. for 4 hours in a nitrogen atmosphere. A laminate was obtained.

  As a result of measuring the surface area ratio and the light transmittance as described above using each of the prepared flexible metal laminates, it was as shown in Table 1.

  From the above results, when the surface area ratio is 1.0018 or less, the circuit can be image-recognized through the polyimide film from the opposite side where the metal foil was laminated after the circuit processing, that is, the metal foil is completely It was revealed that light having a wavelength of 600 nm can be transmitted by 55% or more when etched and measured for light transmittance.

Claims (4)

In a polyimide metal laminate in which a thermoplastic polyimide layer is formed on one side of one or more non-thermoplastic polyimide layers, and a metal is laminated on the surface of the thermoplastic polyimide layer,
The non-thermoplastic polyimide is o-phenylenediamine, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'- A non-thermoplastic polyimide synthesized from a diamine containing a diamine selected from diaminodiphenyl ether and tetracarboxylic dianhydride,
The surface of the metal to be bonded to the thermoplastic polyimide is not roughened, and the surface area ratio of the metal surface to be bonded to the thermoplastic polyimide (the actual surface area, assuming that the measurement surface is smooth) The value obtained by dividing by (1) is 1.0018 or less. The polyimide metal laminated board of Claim 1 whose thickness of a non-thermoplastic polyimide layer is 5-250 micrometers, and whose thickness of a thermoplastic polyimide layer is 0.5-10 micrometers.   The polyimide metal laminate according to claim 1 or 2, wherein the metal is at least one metal selected from the group consisting of copper, nickel, aluminum, stainless steel, and alloys thereof.   The polyimide metal laminate according to any one of claims 1 to 3, wherein the metal has a thickness of 2 to 150 µm.