KR20070021672A - Polyimide film and copper clad laminate using the same - Google Patents

Abstract

The present invention relates to a polyimide film and a copper clad laminate using the same.

The polyimide film according to the present invention is excellent in chemical resistance, in particular alkali resistance, and has no properties without deterioration in mechanical properties or bending properties without the use of a separate inorganic filler.

Description

Polyimide film and copper clad laminate using the same

The present invention relates to a polyimide film and a copper clad laminate using the same.

Polyimide resins having various excellent properties such as heat resistance and electrical insulation are widely used in the electronic field. For example, it is used for a flexible printed circuit board, a base film for COF use, a TAB tape, a base film for high density recording media, or a PVD2 layer metal laminate. Moreover, polyimide resin is used in various forms, such as a solid molded object and a coating agent other than a film body. In the case where the polyimide resin is a film body, it has been widely used in the form of a laminate in which copper is adhered to the film surface with an adhesive, sputtering-copper electroplating of copper, or cast or coated polyimide resin on the copper field. . Thus, when using a polyimide film for the above electronic materials, the dimensional stability at the time of processing is calculated | required for the use.

On the other hand, in order to produce a conductor pattern by the photo etching method, the photosensitive resist is laminated | stacked in the vicinity of 100 degreeC. The photosensitive resist forms a pattern to be left on the conductor with a resist film and is used to remove unnecessary conductors by etching. Flexible printed circuit board manufacturers mainly use dry film as a resist film.

The panel on which the photosensitive agent layer is formed is exposed to ultraviolet rays through a mask to form a latent image of the conductor pattern. In forming the latent pattern image, a mask film based on a polyester film is usually closely adhered by vacuum, and a batch exposure is performed. In many cases, the latent image generated in the exposure process is developed in a sodium carbonate developer, and then the unnecessary copper exposed without a resist is dissolved and removed with an etching solution. Next, the developing resist is stripped using an alkaline solution such as sodium hydroxide, and a series of processes from development to stripping are continuously performed by spraying liquid with a spray on a horizontal conveyor apparatus.

The circuit pattern thus formed is generally stacked and used in multiple layers, and is laminated between 150 and 200 ° C. using a bonding sheet during lamination. At this time, the bending portion does not use the bonding sheet to secure the flexibility. However, even though the bonding sheet was not used, weak adhesion between the imides (not separated) appears at the bent portion. This adhesion phenomenon is related to the chemical resistance of the polyimide. Polyimides are etched by alkali in various chemicals or solvents that go through the pattern formation process. That is, the imide denatures again to amic acid by alkali. Since the surface of the polyimide film modified with amic acid is press-molded by applying heat and pressure in the bonding sheet stacking process, weak adhesion between the amic acids occurs. When such an adhesive phenomenon occurs, the bent portions behave like laminates, and thus the flexibility cannot be exhibited.

Therefore, in order to solve this adhesive phenomenon, the inorganic filler etc. were used for the polyimide part. However, when a large amount of such an inorganic filler or the like is used, there is a problem in that mechanical properties are lowered and flexibility is not expressed.

Thus, the inventors of the present invention while studying a polyimide film without any deterioration in mechanical properties or bending properties without using an additional inorganic filler, the etching rate by 50 ℃, 50% by weight aqueous potassium hydroxide solution By lowering to 0.3 μm / min or less, the polyimide film showed no adhesion phenomenon and confirmed no deterioration in mechanical properties or flexibility.

An object of the present invention is to provide a polyimide film having an etching rate of 0.3 µm / min or less as a polyimide film obtained by reacting a diamine and a dianhydride component.

In addition, the present invention is to provide a copper clad laminate using the polyimide film.

The present invention provides a polyimide film having an etching rate of 0.3 µm / min or less as a polyimide film obtained by reacting a diamine and a dianhydride component.

Moreover, this invention provides the copper clad laminated board in which the said polyimide film is laminated | stacked in one or more layers on the copper field and copper field.

Hereinafter, the present invention will be described in detail.

The present invention provides a polyimide film obtained by reacting a diamine with a dianhydride component and having an etching rate of 0.3 μm / min or less at 50 ° C. and a 50% by weight aqueous potassium hydroxide solution.

As for the etching rate by the said 50 degreeC, 50 weight% potassium hydroxide aqueous solution, 0.1 micrometer / min or less is preferable.

Since the polyimide film according to the present invention is less affected by alkali because of a low etching rate by 50 ° C. and 50% by weight aqueous potassium hydroxide solution, the degree of polyimide back to the polyamic acid even when contacted with alkali is insignificant. Do. If the etching rate exceeds 0.3 μm / min, adhesion phenomenon occurs, and the flexibility is not expressed. Therefore, the polyimide film according to the present invention has the property of not deteriorating mechanical properties or flexibility without adhesion. Therefore, the copper clad laminate using the polyimide film can be usefully used for flexible printed circuit boards, base films for COF applications, TAB tapes, base films for high density recording media, or PVD2 layer metal laminates.

The diamine component used in the present invention is selected from para-phenylenediamine (p-PDA: para-Phenylene diamine) or 4,4'-oxydianiline (4,4'-ODA: 4,4'-Oxydianiline). 3,4'-oxydianiline (3,4'-ODA: 3,4'-oxydianiline) and meta-phenylenediamine (m-PDA: m-Phenylene diamine) other than the diamine component , 2,2-bis (4- [4-aminophenoxy] -phenyl) propane (BAPP: 2,2-bis (4- [4-aminophenoxy] -phenyl) propane), 2,2'-dimethyl-4 , 4'-diamino biphenyl (m-TB-HG: 2,2'-Dimethyl-4,4'-diamino biphenyl), 1,3-bis (4-aminophenoxy) benzene (TPER: 1,3 -bis (4-aminophenoxy) benzene), 4,4'-diamino benzanilide (DABA: 4,4'-diamino benzanilide), or 4,4'-bis (4-aminophenoxy) biphenyl (BAPB : At least one selected from the group consisting of 4,4'-bis (4-aminophenoxy) biphenyl), and the sum of the total mole% of the selected diamine components is 50 to 100 based on the total mole% of the diamine components used. Mol%, preferably Crab is 80-100 mol%. If the sum of the total mole% of the diamine components used is less than 50 mole%, adhesion occurs.

The dianhydride component used in the present invention is pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA: 3,3', 4,4'-biphenyltetracarboxylic dianhydride), 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA: 3,3', 4,4'-benzophenonetetracarboxilic dianhydride), 4,4'-oxy At least one selected from the group consisting of diphthalic anhydride (ODPA: 4,4'-oxydiphthalic anhydride), wherein the sum of the total mole percent of the selected dianhydride component is the total mole of the dianhydride component used. It should be 50-100 mol%, preferably 70-100 mol% with respect to%. If the sum of the total mole% of the dianhydride components used is less than 50 mole%, adhesion occurs.

However, pyromellitic dianhydride (PMDA) of the dianhydride component has the advantage of increasing the glass transition temperature, but when used in excess of 60 mol% PMDA is less alkali resistance, so PMDA is used dianhydride Preference is given to using up to 60 mol% relative to the total mol% of the ride component.

In the present invention, it is also possible to add a small amount of other diamines, other dianhydrides, or other compounds other than the above compounds as necessary.

The manufacturing method of the polyimide film which concerns on this invention,

1) adding a diamine component to an organic solvent and stirring to dissolve,

2) stirring and polymerizing with adding dianhydride while cooling the solution obtained in step 1) to obtain a polyamic acid varnish,

3) coating the polyamic acid varnish obtained in step 2) on a substrate, and

4) hardening the coated polyamic acid varnish obtained in step 3) to obtain a polyimide film.

Diamine and dianhydride used in the present invention is preferably reacted at the same molar ratio. If a large amount of carboxylic acid remains in the polyimide film, a problem of accelerating the hydrolysis rate of the polyimide film occurs, thereby deteriorating the stability of the polyimide film. In addition, in the case where a large amount of amine remains in the polyimide film, the viscosity of the polyamic acid solution does not become high enough, so that the film forming ability of the polyimide film is low, making molding into a film difficult.

As a solvent that may be used for the preparation of the polyamic acid varnish according to the present invention, N-methylpyrrolidinone (NMP: N-methylpyrrolidinone), N, N-dimethylacetamide (DMAc: N, N-dimethylacetamide), tetrahydro Furan (THF: tetrahydrofuran), N, N-dimethylformamide (DMF: N, N-dimethylformamide), dimethyl sulfoxide (DMSO: dimethylsulfoxide), cyclohexane, acetonitrile or mixtures thereof are preferred. Do. However, the kind of the solvent is not limited to these.

The polyamic acid varnish may be prepared in the form of random (random copolymer) or block copolymer (block copolyimer), the reaction temperature is preferably in the range of 0 ~ 100 ℃. The viscosity of the polyamic acid varnish is preferably 2,000 to 50,000 cps, which is preferable in terms of process for producing an imide film or copper clad laminate.

In order to obtain the polyimide film of this invention from a polyamic-acid solution, various methods, such as the thermal method of thermally dehydrating and ring closing, and the chemical method using a dehydrating agent, can be used. When the chemical method is used, mechanical properties such as elongation and tensile strength of the resulting polyimide film are excellent, and there are advantages such as imidization in a short time. In the present invention, a thermosetting or chemical curing method may be used alone, or both may be used in combination.

Moreover, this invention provides the copper clad laminated board in which the said polyimide film is laminated | stacked in one or more layers on the copper field and copper field.

The copper clad laminated board can form copper directly by vapor-depositing or sputtering copper to a polyimide film, and may be a copper clad laminated board which bonded the metal foil and the polyimide film using the adhesive agent. At this time, the adhesive used is an epoxy resin, a polyamide resin, a phenol resin, an acrylic resin, a polyimide resin, a rubber resin, or the like, mixed with a solvent alone or in various mixing ratios. What added the additive can be used.

When the polyimide film according to the present invention is used in a copper clad laminate, the coefficient of linear expansion (CTE) is preferably 30 × 10 ⁻⁶ / ° C. or less, more preferably 25 × 10 ⁻⁶ / ° C. or less. In addition, the polyimide film preferably has a glass transition temperature (Tg) of 300 ° C or higher. If the coefficient of linear expansion of the polyimide film itself exceeds 30 × 10 ⁻⁶ / ° C., the polyimide film becomes larger than the coefficient of linear expansion of 17 × 10 ⁻⁶ / ° C. and the curl of the copper clad laminate becomes severe and difficult to use. In addition, if the glass transition temperature of the polyimide film is less than 300 ° C., even in the case of the continuous curing step, there may not be a big problem, but when the thermal imidization is performed in a batch manner, it is wound on the roll. Thermal curing can lead to the bonding of polyimide films with copper.

In order to achieve the linear expansion coefficient, 4,4'-oxydianiline (4,4'-ODA) or 3,4'-oxydianiline (3,4'-ODA) component as a diamine component in the production of polyimide film When using these, they are each preferably 50 mol% or less with respect to the total mol% of the diamine component used. Further, 2,2-bis (4- [4-aminophenoxy] -phenyl) propane (BAPP), 1,3-bis (4-aminophenoxy) benzene (TPER), 4,4'-bis (4 When using -aminophenoxy) biphenyl (BAPB), they are preferably 20 mol% or less relative to the total mol% of the diamine components used in terms of coefficient of thermal expansion. In addition, since the glass transition temperature tends to decrease as the content of these components increases, it is preferable not to exceed the above mol% in terms of glass transition temperature.

In addition, when the polyimide film is used for the production of a copper clad laminate, 4,4'-oxydiphthalic anhydride (ODPA) is used as a dianhydride component in the production of the polyimide film in consideration of the coefficient of linear expansion and the glass transition temperature. Or when using 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA), they are preferably used at 30 mole% or less relative to the total mole% of the dianhydride component used. .

Hereinafter, preferred examples are provided to aid in understanding the present invention. However, the following examples are merely provided to more easily understand the present invention, and the contents of the present invention are not limited thereto.

The physical property evaluation method in an Example and a comparative example is as follows.

[ Coefficient of linear expansion (CTE)  Measure]

Using Mettler Toledo's TMA (SDTA840), the temperature was raised to 250 ° C. at a temperature increase rate of 10 ° C./min, held at that temperature for 10 minutes, and then cooled to 50 ° C. at 10 ° C./min. The temperature was further raised at a temperature increase rate of 10 ° C./min to 350 ° C. to calculate an average CTE from 100 ° C. to 200 ° C. during the temperature increase. In addition, the glass transition temperature (Tg) was measured from this TMA apparatus.

[Measurement of Etching Speed]

A 50 wt% aqueous potassium hydroxide solution was prepared and used as an etching solution. The formed polyimide film thickness was measured 10 times and the average value was x micrometer. The polyimide film having the thickness measured was immersed in the solution after the etching solution was heated to 50 ° C., and the film was stirred inside the solution. It was immersed so that both surfaces were etched, and the time which all the polyimide resin disappeared was measured, and the value which divided the initial thickness by the time required for etching was made into the etching rate. In addition, about the polyimide film with long etching time, the value which divided | segmented the quantity which reduced the film thickness by the time required for etching was made into the etching rate.

[Adhesive phenomenon observation]

The prepared polyamic acid varnish was coated on the copper field for easy handling and cured, and then the sample was cut into a size of 15 cm × 15 cm. The cut sample was immersed in 50 ° C. 50% potassium hydroxide solution with stirring for 15 minutes. After washing with water, it was dried for 30 minutes in a dry oven at 50 ℃. After preparing two such samples, the polyimide surface was brought into contact with each other, and a vacuum pad was performed at 180 ° C. for 1 hour using a cushion pad.

Example  One  : Production of Polyimide Film

21.52 g of p-phenylene diamine (p-PDA) (0.20 mol) was flowed with nitrogen into a 2000 ml four-necked round bottom flask equipped with a thermometer, stirrer and nitrogen inlet and powder dispensing funnel. To 20.42 g of 2,2-bis (4- [4-aminophenoxy] -phenyl) propane (BAPP) (0.05 mol) was added 1000 ml of N-methylpyrrolidinone (NMP) and stirred to dissolve completely. 21.96 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) (0.08 mol) and 56.11g of 3,3', 4,4 ' -Benzophenonetetracarboxylic dianhydride (BTDA) (0.17 mol) was gradually added while stirring and polymerization to obtain a polyamic acid varnish having a viscosity of 15,000 cps.

The obtained polyamic acid varnish was coated on a glass plate using a doctor blade. The coated varnish was heated in an oven at 400 ° C. for 5 minutes to obtain a polyimide film having a final thickness of 15 μm. The film was evaluated for properties, and the results are shown in Table 1.

Example  2 ~ 5  : Production of Polyimide Film

It mix | blended in the ratio of the diamine and dianhydride component shown in Table 1, and carried out similarly to the method of Example 1, and obtained the polyimide film. The characteristics of this film were evaluated and the results are shown in Table 1.

Compounding cost Example 1 Example 2 Example 3 Example 4 Example 5 Diamine (mol%) 4,4'-ODA - - 20 - 20 4,4'-PDA 80 70 80 50 60 m-TB-HG - 30 - 50 - BAPP 20 - - - 20 Dianhydride (mol%) PMDA - 50 - - 50 BPDA 30 - 100 20 50 BTDA 70 50 80 - CTE 44.7 20.0 14.3 43.5 42.13 Etching speed 0.06 0.10 0.09 0.05 0.24 Adhesion none none none none none

As shown in Table 1, the polyimide film according to the present invention was confirmed that the etching rate is 0.3㎛ / min or less, no adhesion phenomenon.

Therefore, it can be seen that the polyimide film according to the present invention has an etching rate of 0.3 μm / min or less without using an inorganic filler, and does not exhibit adhesive properties, thereby reducing mechanical properties and flexibility.

Comparative example  One  :

17.15 g of p-phenylene diamine (p-PDA) (0.159 mol) and 4,4'- were flowed into a 2000 ml four-necked round bottom flask equipped with thermometer, stirrer and nitrogen inlet and powder inlet. 1000 ml of N-methylpyrrolidinone (NMP) was added to oxydianiline (4,4'-ODA) (0.106 mol), followed by stirring to dissolve completely. 57.67 g of pyromellitic dianhydride (PMDA) (0.264 mol) was gradually added while cooling the solution to 15 DEG C or lower, followed by polymerization to obtain a polyamic acid varnish having a viscosity of 15,000 cps.

The obtained polyamic acid varnish was coated on a glass plate using a doctor blade. The coated varnish was heated in an oven at 400 ° C. for 5 minutes to obtain a polyimide film having a final thickness of 15 μm. The characteristics of this film were evaluated and the results are shown in Table 2.

Comparative example  2 ~ 5  :

It mix | blended in the ratio of the diamine and dianhydride component shown in Table 2, and carried out similarly to the method of the comparative example 1, and obtained the polyimide film. The characteristics of this film were evaluated and the results are shown in Table 2.

Compounding cost Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Diamine (mol%) 4,4'-ODA 40 40 100 40 100 4,4'-PDA 60 60 60 - Dianhydride (mol%) PMDA 100 70 100 70 30 BPDA - 30 - - - ODPA - - - 30 - BPADA - - - - 70 CTE 24.4 24.0 40.3 34.4 45.0 Etching speed 6.55 0.45 8.33 0.56 0.85 Adhesion has exist has exist has exist has exist has exist

※ BPADA: Bisphenol-A dianhydride

As shown in Table 2, the polyimide film prepared in the comparative example was confirmed that the etching rate is 0.3㎛ / min or more, the adhesion phenomenon occurs.

The polyimide film according to the present invention is excellent in chemical resistance, in particular alkali resistance, and has no properties without deterioration in mechanical properties or bending properties without the use of a separate inorganic filler. Therefore, the copper clad laminate using the polyimide film can be usefully used for flexible printed circuit boards, base films for COF applications, TAB tapes, base films for high density recording media, or PVD2 layer metal laminates.

Claims (7)

A polyimide film obtained by reacting a diamine with a dianhydride component, wherein the polyimide film has an etching rate of 0.3 µm / min or less at 50 ° C. and a 50% by weight aqueous potassium hydroxide solution. The method of claim 1, wherein the diamine component is para-phenylenediamine (p-PDA: para-Phenylene diamine) or 4,4'- oxydianiline (4,4'-ODA: 4,4'-Oxydianiline) 3,4'-oxydianiline (3,4'-ODA: 3,4'-oxydianiline), meta-phenylenediamine (m-PDA: m-Phenylene diamine) in addition to the diamine component ), 2,2-bis (4- [4-aminophenoxy] -phenyl) propane (BAPP: 2,2-bis (4- [4-aminophenoxy] -phenyl) propane), 2,2'-dimethyl- 4,4'-diamino biphenyl (m-TB-HG: 2,2'-Dimethyl-4,4'-diamino biphenyl), 1,3-bis (4-aminophenoxy) benzene (TPER: 1, 3-bis (4-aminophenoxy) benzene), 4,4'-diamino benzanilide (DABA: 4,4'-diamino benzanilide), or 4,4'-bis (4-aminophenoxy) biphenyl ( BAPB: at least one selected from the group consisting of 4,4'-bis (4-aminophenoxy) biphenyl), wherein the sum of the total mole% of the selected diamine components is 50 to the total mole% of the diamine components used. Characterized by being 100 mol% Polyimide film made into. 3. The diamine component according to claim 2, wherein the 4,4'-oxydianiline (4,4'-ODA) or 3,4'-oxydianiline (3,4'-ODA) component of the diamine component is used. 50 mole% or less relative to the total mole%, and 2,2-bis (4- [4-aminophenoxy] -phenyl) propane (BAPP), 1,3-bis (4-aminophenoxy) benzene (TPER ), And the molar ratio of 4,4'-bis (4-aminophenoxy) biphenyl (BAPB) is 20 mol% or less relative to the total mole percent of the diamine component used. According to claim 1, The dianhydride component, pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride), 3,3', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA: 3,3 ', 4,4'-benzophenonetetracarboxilic dianhydride), 4,4' -Oxydiphthalic anhydride (ODPA: 4,4'-oxydiphthalic anhydride) containing at least one selected from the group consisting of, the sum of the total mole percent of the selected dianhydride component of the dianhydride component used It is 50-100 mol% with respect to a total mol%, The polyimide film characterized by the above-mentioned. 5. The polyimide film of claim 4, wherein the pyromellitic dianhydride (PMDA) in the dianhydride component comprises less than 60 mol% relative to the total mole% of the dianhydride component used. 6. 5. The method of claim 4, wherein 4,4′-oxydiphthalic anhydride (ODPA) or 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) of the dianhydride component is used. 30 mole% or less relative to the total mole% of the dianhydride component. The copper clad laminated board in which the polyimide film of any one of Claims 1-6 is laminated | stacked on the copper field and the copper field in one or more layers.