JP4106929B2 - Metal laminated film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal laminated film that can be used as a flexible printed wiring board and has excellent adhesion between a metal and an insulating layer.
[0002]
[Prior art]
Conventionally, a flexible printed wiring board having a three-layer structure of polyimide film / adhesive / metal foil using epoxy, acrylic, polyamide, phenol, or the like as an adhesive is well known. There were many cases where there was a problem in the adhesive strength because it was determined by the properties of the agent. Also, JP-A-4-146690 and JP-A-2000-167980 are known as examples of using a thermoplastic polyimide precursor as an adhesive for improving heat resistance and thermocompression bonding of a metal foil at a high temperature. However, since the metal foil must be thermocompression bonded at a high temperature, there is a problem of residual distortion after processing, or the thickness of the metal foil used for pressure bonding is usually 10 μm or more, and patterning with a narrow pitch is difficult. there were.
[0003]
In addition, a flexible printed wiring board having a two-layer structure in which a metal is directly metalized on a non-thermoplastic polyimide is also known, but has a drawback that adhesion is low and particularly a decrease in adhesion after thermal load is large.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned disadvantages of the prior art and provide a laminated film in which the adhesion between a metal layer and a film insulating layer is improved in a laminated film in which a polyimide film and a metal are laminated.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have studied, and after coating a thermoplastic polyimide varnish on one side or both sides of a non-thermoplastic polyimide film, it is dried, and the thickness of the thermoplastic polyimide after drying There Ri 0.4 to 5 [mu] m der, and a metal laminated film improves adhesion of the metal layer formed by metallization on one or both sides of the glass transition temperature of Ru 0.99 ° C. to 280 ° C. der film of the thermoplastic polyimide The present inventors have found that there is an effect, and that a metal laminated film obtained by copper plating on the metal laminated film is effective in improving the adhesion, and has led to the present invention.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the non-thermoplastic polyimide means a polyimide that does not further cure by applying heat, but does not have a property of being softened by heat. For example, pyromellitic dianhydride Examples thereof include polyimide obtained by dehydrating and curing polyamic acid obtained from 4,4′-diaminodiphenyl ether.
[0007]
Specific examples of non-thermoplastic polyimides include non-thermoplastic polyimide series under the trade name “Kapton” (manufactured by Toray DuPont and DuPont), and non-thermoplastic polyimide series under the trade name “UPILEX” (manufactured by Ube Industries). And non-thermoplastic polyimide series under the trade name “Apical” (manufactured by Kaneka Chemical Co., Ltd.).
[0008]
The thermoplastic polyimide refers to a polyimide that generates plasticity when heated, and examples thereof include those that reduce the cohesion between molecules by reducing the concentration of the generated imide group in the repeating unit.
[0009]
Specific examples of the thermoplastic polyimide varnish include trade name “Iupite UPA-N111” (manufactured by Ube Industries), trade name “Iupite UPA-N221” (manufactured by Ube Industries), and the like. It is preferable to apply the thermoplastic polyimide varnish so that the coating thickness after drying is 0.4 μm to 5 μm. The drying temperature is preferably in the range of 100 ° C to 300 ° C, and the drying time is preferably in the range of 1 minute to 20 minutes. The glass transition point of the coated thermoplastic polyimide is preferably in the range of 150 ° C to 280 ° C.
[0010]
The term “metalizing” as used in the present invention refers to deposition of metal vapor on the surface of a film or sputtering, and is distinguished from metal plating, metal foil lamination, and the like. Specific methods of metallizing include sputtering, vacuum deposition, ion beam deposition, electron beam deposition, etc., but considering the stability of processing, the simplification of the process, less curling, film uniformity, etc. A sputtering method is preferred. The metal used for metalizing is at least one selected from copper, nickel, chromium, manganese, aluminum, iron, molybdenum, cobalt, tungsten, vanadium, titanium, tantalum and the like. 1-500 nm is preferable and, as for the thickness of the metal thin film formed by metalizing, the range of 5 nm-200 nm is more preferable.
[0011]
After metallizing, a copper plating layer is formed by electrolytic plating or electroless plating. The thickness of the copper plating layer is preferably in the range of 1 μm to 40 μm. If the thickness of the copper plating layer is less than 1 μm, problems such as an increase in wiring resistance when wiring is formed are undesirable. If the thickness exceeds 40 μm, the accuracy of the pitch width of high-density wiring decreases. It is not preferable.
[0012]
【Example】
Examples of the present invention are shown below. However, the present invention is not limited to the following examples.
[0013]
The measurement in this example was performed according to the following method.
<Measurement of film thickness>
It measured from the cross-sectional photograph of SEM.
<Measurement of adhesion of metal layer: Peel test>
The metal laminated film was cut into a width of 10 mm and a length of 100 mm, and a 90-degree peel test was performed under the condition of a pulling speed of 50 mm / min.
[Example 1]
On one side of 25 μm thick “Kapton 100EN” (trade name, manufactured by Toray DuPont) which is a non-thermoplastic polyimide film, “Iupitite UPA-N111C” (trade name, manufactured by Ube Industries) is a thermoplastic polyimide varnish. A solution diluted with tetrahydrofuran to a solid content of 15% was applied and dried at 120 ° C. for 1 minute and then at 180 ° C. for 10 minutes. The thickness of the coating part was 0.7 μm. The film thus obtained is put into a sputtering apparatus (SAMCO PD-10 type), and the pressure is reduced to 1.3 × 10 −3 Pa while cooling the diffusion pump using liquid nitrogen to remove the impure gas. After that, argon gas was introduced and copper was sputtered at 0.27 Pa to form a copper thin film on the film surface. The thickness of the copper thin film was 150 nm. Thereafter, electroplating with an aqueous copper sulfate solution was performed under a current density of 3 A / dm 2 to obtain a metal laminated film. The thickness of the copper layer by electrolytic plating was 8 μm. This metal laminated film was cut into a width of 10 mm and a length of 100 mm, and a 90-degree peel test was performed under the condition of a pulling speed of 50 mm / min. The measurement result at room temperature was 9.1 N / cm, and the measurement result after thermal load at 150 ° C. × 240 hr was 6.1 N / cm.
[0014]
[Example 2]
A 25 μm thick “Kapton 100EN” (trade name: manufactured by Toray DuPont) film is coated with “Iupite UPA-N221C” (trade name: manufactured by Ube Industries), which is a thermoplastic polyimide varnish, in tetrahydrofuran with a solid content of 15%. The diluted solution was applied and dried at 120 ° C. for 1 minute and then at 180 ° C. for 10 minutes. The thickness of the coating part was 0.9 μm. The film thus obtained is put into a sputtering apparatus (SAMCO PD-10 type), and the pressure is reduced to 1.3 × 10 −3 Pa while cooling the diffusion pump using liquid nitrogen to remove the impure gas. After that, argon gas was introduced and copper was sputtered at 0.27 Pa to form a copper thin film on the film surface. The thickness of the copper thin film was 80 nm. Thereafter, electroplating with an aqueous copper sulfate solution was performed under a current density of 3 A / dm 2 to obtain a metal laminated film. The thickness of the copper layer by electrolytic plating was 10 μm. This metal laminated film was cut into a width of 10 mm and a length of 100 mm, and a 90-degree peel test was performed under the condition of a pulling speed of 50 mm / min. The measurement result at room temperature was 9.8 N / cm, and the measurement result after a thermal load of 150 ° C. × 240 hr was 6.8 N / cm.
[0015]
[Example 3]
Apply a solution of "Iupitite UPA-N111C" (trade name: manufactured by Ube Industries Co., Ltd.) diluted with tetrahydrofuran to a solid content of 15% to "Kapton 100EN" (trade name: manufactured by Toray DuPont) with a thickness of 25 µm. And then dried at 120 ° C. for 1 minute and then at 180 ° C. for 10 minutes. The thickness of the coating part was 0.7 μm. The film thus obtained is put into a sputtering apparatus (SAMCO PD-10 type), and the pressure is reduced to 1.3 × 10 −3 Pa while cooling the diffusion pump using liquid nitrogen to remove the impure gas. After that, argon gas was introduced and copper was sputtered at 0.27 Pa to form a copper thin film on the film surface. The thickness of the copper thin film was 150 nm. Thereafter, electroplating with an aqueous copper sulfate solution was performed under a current density of 3 A / dm 2 to obtain a metal laminated film. The thickness of the copper layer by electrolytic plating was 25 μm. This metal laminated film was cut into a width of 10 mm and a length of 100 mm, and a 90-degree peel test was performed under the condition of a pulling speed of 50 mm / min. The measurement result at room temperature was 11.0 N / cm, and the measurement result after thermal load at 150 ° C. × 240 hr was 7.1 N / cm.
[0016]
[Example 4]
“Iupitite UPA-N111C” (trade name: manufactured by Ube Industries) is applied to “Kapton 100EN” (trade name: manufactured by Toray DuPont) having a thickness of 25 μm, followed by 1 minute at 120 ° C., followed by 10 at 180 ° C. Minute drying was performed. The thickness of the coating part was 2.0 μm. The film thus obtained is put into a sputtering apparatus (SAMCO PD-10 type), and the pressure is reduced to 1.3 × 10 −3 Pa while cooling the diffusion pump using liquid nitrogen to remove the impure gas. After that, argon gas was introduced and copper was sputtered at 0.27 Pa to form a copper thin film on the film surface. The thickness of the copper thin film was 100 nm. Thereafter, electroplating with an aqueous copper sulfate solution was performed under a current density of 3 A / dm 2 to obtain a metal laminated film. The thickness of the copper layer by electrolytic plating was 35 μm. This metal laminated film was cut into a width of 10 mm and a length of 100 mm, and a 90-degree peel test was performed under the condition of a pulling speed of 50 mm / min. The measurement result at room temperature was 8.0 N / cm, and the measurement result after heat load at 150 ° C. × 240 hr was 6.1 N / cm.
[0017]
[Comparative Example 1]
“Kapton 100EN” (trade name: manufactured by Toray DuPont) with a thickness of 25 μm is placed in a sputtering apparatus (PD-10 model manufactured by SAMCO), and the pressure is 1.3 × 10 while cooling the diffusion pump using liquid nitrogen. The impure gas was degassed by reducing the pressure to -3 Pa, and then argon gas was introduced and copper was sputtered at 0.27 Pa to form a copper thin film on the film surface. The thickness of the copper thin film was 150 nm. Thereafter, electroplating with an aqueous copper sulfate solution was performed under a current density of 3 A / dm 2 to obtain a metal laminated film. The thickness of the copper layer by electrolytic plating was 8 μm. This metal laminated film was cut into a width of 10 mm and a length of 100 mm, and a 90-degree peel test was performed under the condition of a pulling speed of 50 mm / min. The measurement result at room temperature was 4.8 N / cm, and the measurement result after thermal load of 150 ° C. × 240 hr was 2.0 N / cm.
[0018]
[Comparative Example 2]
“Kapton 100EN” (trade name: manufactured by Toray DuPont) with a thickness of 25 μm is placed in a sputtering apparatus (PD-10 model manufactured by SAMCO), and the pressure is 1.33 × 10 while cooling the diffusion pump using liquid nitrogen. The impure gas was degassed by reducing the pressure to −3 Pa, and then argon gas was introduced and copper was sputtered at 0.266 Pa to form a copper thin film on the film surface. The thickness of the copper thin film was 80 nm. Thereafter, electroplating with an aqueous copper sulfate solution was performed under a current density of 3 A / dm 2 to obtain a metal laminated film. The thickness of the copper layer by electrolytic plating was 10 μm. This metal laminated film was cut into a width of 10 mm and a length of 100 mm, and a 90-degree peel test was performed under the condition of a pulling speed of 50 mm / min. The measurement result at room temperature was 4.8 N / cm, and the measurement result after thermal load at 150 ° C. × 240 hr was 1.5 N / cm.
[0019]
【The invention's effect】
As described above, according to the present invention, a metal laminated film having excellent adhesion between the metal layer and the insulating layer can be obtained.

Claims (4)

After coating the thermoplastic polyimide varnish on one or both sides of the non-thermoplastic polyimide film, it is dried, the thickness of the thermoplastic polyimide after drying Ri 0.4 to 5 [mu] m der, and the glass transition of the thermoplastic polyimide metal laminated film temperature is by metallizing a metal layer on one or both sides of 0.99 ° C. to 280 ° C. der Ru film. The metal laminated film according to claim 1, wherein the metal layer by metalizing has a thickness of 1 to 500 nm . The metal laminated film formed by copper-plating the metal laminated film surface of Claim 1 or 2 . The metal laminated film according to claim 3, wherein the copper plating layer has a thickness of 1 to 40 μm .