Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
  • B32B37/10—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
  • B32B15/088—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyamides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
  • B32B27/281—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42 comprising polyimides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/03—3 layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
  • B32B2307/206—Insulating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
  • B32B2309/02—Temperature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
  • B32B2309/12—Pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2311/00—Metals, their alloys or their compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2379/00—Other polymers having nitrogen, with or without oxygen or carbon only, in the main chain
  • B32B2379/08—Polyimides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2457/00—Electrical equipment

Definitions

• the present invention relates to a thick layer polyimide metal clad laminate, and more particularly to a thick layer polyimide metal clad laminate in which a polyimide film has a specific range of mechanical and thermal properties for producing a product with excellent process stability and superior dimensional stability.
• a flexible metal clad laminate is a laminate of a conductive metal foil and an insulating polymer, is amendable to microcircuit processing, and allows bending in a narrow space. Thus, it has been used increasingly in a wide spectrum of applications, as current electronic appliances have been downsized in dimension and weight.
• These flexible metal clad laminates are classified into a two-layered and a three-layered type.
• the three-layered type metal clad laminate is manufactured by attaching a polyimide film with a metal foil, using an epoxy-based or urethane-based adhesive layer.
• heat resistance and flame retardancy are deteriorated due to thermally unstable adhesive layers as well as thermal stability, dimensional changes are large after an etching and a heat treatment process. It can reduce the productivity of a manufacturing process of printed circuit boards.
• a two-layered type flexible metal clad laminate without using an adhesive layer has been developed and used. There are two different methods to prepare the two-layered flexible metal laminates which have excellent heat resistance, a casting method and a lamination method. In the case of casting method, the flexible metal clad laminate is manufactured by following description.
• a polyamic acid solution is coated on a conductive metal foil and then thermal curing is conducted to change polyamic acid to polyimide on the conductive metal foil.
• a thermoplastic polyimide layer is introduced onto an outermost polyimide layer and then laminated with the metal foil to prepare the double-sided metal clad laminate.
• a thermoplastic polyimide layer is formed on one side or both sides of a polyimide film and then laminate with a metal foil to prepare a single-sided or a double-sided metal clad laminate.
• an appearance problem such as a formation of foam
• the mechanical strength and chemical resistance are reduced by decreasing in the degree of curing of polyamic acid.
• the dimensional stability is also reduced because a remaining solvent in the film is difficult to remove.
• a thick layer polyimide metal clad laminate having a thick polyimide layer may be manufactured by using the lamination method.
• the present inventors found problems in an appearance (creases, oblique lines, longitudinal stripes, or the like) and a dimensional stability of two-layered flexible copper clad laminate prepared by the lamination method. In order to solve these problems, the present inventors have conducted various studies and then finally completed the present invention.
• An object of the present invention is to provide mechanical and thermal properties of a polyimide film, which are needed for producing a metal clad laminate having a thick polyimide with good appearance and mechanical properties using lamination method.
• the present invention is directed to providing a metal clad laminate with thick polyimide layer.
• the present inventors found that when thick layer polyimide metal clad laminate having a thick polyimide is prepared by lamination method, the mechanical and thermal properties of polyimide film, which is used for core layer in polyimide laminate, should have a specific range to get the excellent process stability and dimensional stability, and then completed the present invention.
• the thick layer polyimide metal clad laminate according to the present invention can be prepared by a lamination method.
• the appearance problems creases, oblique lines, longitudinal stripes, or the like
• these metal clad laminate have an excellent dimensional stability.
• the present invention is directed to providing a manufacturing of single sided, which means one side attachment of metal with polyimide film, or double sided, which means both sides attachment of metal foil with polyimide film, thick layer polyimide metal clad laminates using lamination method
• the polyimide laminate which consists of a thermoplastic polyimide layer formed on one side or both sides of the core polyimide film, and the core polyimide film has an elongation of 30% or less and a tensile modulus of 3GPa or more, which is measured by IPC-TM-650 (2.4.19) method, and a coefficient of thermal linear expansion (CTE) of 5 to 30ppm/°C, which is calculated from 100 to 250°C.
• CTE coefficient of thermal linear expansion
• the present invention can improve appearance defects occurring after lamination process, by defining ranges of mechanical and thermal properties of the core polyimide film, and furthermore, the present invention was completed by finding an improvement of dimensional stability of the thick layer polyimide metal clad laminate.
• the present invention is characterized in that the core polyimide film has an elongation of 30% or less and a tensile modulus of 3GPa or more, which is measured by IPC-TM-650 (2.4.19) method, and a coefficient of thermal linear expansion (CTE) of 5 to 30ppm/°C, which is calculated from 100 to 250°C.
• the present invention was completed by finding that, if the above ranges are satisfied, a thick layer polyimide metal clad laminate can be manufactured by a lamination method and this metal clad laminate having excellent dimensional stability can be manufactured.
• the polyimide film can be laminated with the metal foil through a lamination process, when it has an elongation of 30% or less, more specifically, 25% or less, and more preferably in a range of 5 to 30%. If above 30%, flairs may occur, and thus appearance defects, such as, longitudinal stripes, wrinkles, or the like, may occur on the product after lamination, with the result that a product having favorable appearance cannot be manufactured.
• the polyimide film in this invention has a tensile modulus of 3GPa or more, more specifically, 4GPa or more, and more preferably, 4 to 8GPa. If PI film has a tensile modulus of below 3GPa, appearance defects are shown after lamination process because the polyimide film has a soft characteristic and its elongation is high, as described above.
• the polyimide film in this invention has a coefficient of thermal linear expansion (CTE) of 5 to 30ppm/°C, and more preferably 10 to 25ppm/°C, which is calculated from 100 to 250°C, a metal clad laminate with excellent dimensional stability can be manufactured. If above 30ppm/°C or below 5ppm/°C, a difference in CTE between the polyimide film and the metal foil, especially, a copper foil, becomes large, thereby increasing dimensional changes after etching and heat treatment.
• CTE coefficient of thermal linear expansion
• the polyimide film In order to manufacture a thick layer polyimide metal clad laminate, the polyimide film preferably has a thickness of 25 ⁇ m or more, and specifically, 25 to 150 ⁇ m.
• the polyimide laminate is prepared by coating thermoplastic polyamic acid on one side or both sides of the core polyimide film, followed by drying and heat treatment.
• the lamination process means that the polyimide laminates are attached with the conductive metal foil through high-temperature lamination.
• the conductive metal foil may be formed on one side or both sides of the polyimide laminate.
• the conductive metal foil may be a copper foil, a stainless foil, an aluminum foil, a nickel foil, an alloy foil of two or more kinds, or the like, but the kind of conductive metal foil is not limited as long as the objects pursued in the present invention can be satisfied. Also, the thickness of the conductive metal foil is not limited, but preferably, may be 9 to 70 ⁇ m for good processability.
• the polyimide film used as the core layer may be subjected to surface treatment, for example, corona treatment, plasma treatment, or the like, so as to improve the adhesive strength with the thermoplastic polyimide layer, but the method for treatment is not limited as long as the objects pursued in the present invention can be satisfied.
• surface treatment methods may be used to increase roughness or change a chemical structure of a surface layer of the polyimide film.
• thermoplastic polyimide layer used in the present invention is not particularly limited.
• a polyamic acid solution which is a precursor of thermoplastic polyimide
• thermoplastic polyimide layer is formed on the core polyimide film.
• knife coating, roll coating, die coating, curtain coating, and the like in a method for coating the polyamic acid solution on the polyimide film, but the coating method is not limited as long as the objects pursued in the present invention can be satisfied.
• the polyamic acid solution which is a polyimide precursor
• the heat treatment method any methods may be applied, but the heat treatment method is generally performed by forming the gel film through the applying and drying of partially imidized polyimide resin or polyimide precursor resin and then fixing it within a drying furnace for a predetermined time or continuous moving it into the drying furnace for a predetermined time.
• the temperature for heat treatment is generally 300°C and more, and more preferably, the high-temperature treatment of 300 to 500°C is performed.
• any known heating method may be applied as long as the objects pursued in the present invention can be satisfied.
• thermoplastic polyimide and thermoplastic polyamic acid used in the present invention
• a glass transition temperature (Tg) is 180°C or higher, and more preferably, 200 to 300°C, which are measured after complete imidization.
• any thermoplastic polyimide resin or polyamic acid solution, which has thermoplastic property may be used, and the kind thereof is particularly not limited.
• a thickness after final curing process of the thermoplastic polyimide layer may be 3 to 20 ⁇ m, and this thickness range is preferable since an adhesive strength with the metal foil can be stably secured and manufacturing stability can be obtained.
• the temperature of the lamination process is particularly not limited, but it is preferable to perform heating over a glass transition temperature of the thermoplastic polyimide.
• the temperature for lamination process is generally 30 to 200°C higher than a glass transition temperature (Tg) of the thermoplastic polyimide.
• the pressure for lamination process is preferably 50 to 200kgf/cm as a linear pressure. When the pressure is high, the temperature of lamination process can be lowered, thus, it is necessary to use pressure as high as possible to get the high productivity.
• the present invention proposed mechanical and thermal properties of the polyimide film used as the core layer, so as to produce a product having excellent process stability and dimensional stability, in manufacturing a thick layer metal clad laminate having a thick polyimide layer by using the lamination method. According to the present invention, process problems, which may occur when the thick layer metal clad laminate is manufactured by using the lamination method, can be minimized, and a thick layer metal clad laminate having excellent properties can be manufactured.
• a flare phenomenon is that, when a film is contacted with a high-temperature laminator roll, the film is deformed like a wave form.
• creases wrinkles
• creases may occur on a copper foil after lamination with the Cu foil. These creases are formed depending on the degree of flare of polyimide laminate.
• the degree of flare was evaluated according to the following criteria.
• ⁇ exhibits that there are big flares and creases after passing through the laminator roll are formed by these flares.
• ⁇ exhibits that there are weak flares, but creases after passing through the laminator roll are not formed.
• ⁇ exhibits the high processing stability without causing flares.
• the coefficient of thermal linear expansion was obtained by raising the temperature to 400 °C at a speed of 5°C/min and averaging the thermal expansion values measured between 100 °C and 250 °C with a thermomechanical analyzer (TMA).
• TMA thermomechanical analyzer
• the specimen was subjected to heat treatment at 150°C for 30 minutes, and then stored in a chamber with 23°C and 50% RH condition during 24 hours. Then, the distance between holes was measured again. Comparing the above measured distances with the distances of holes of original sample, MD and TD dimensional changes after heat treatment were calculated.
• Diamines of TPER 119.06g and PDA 14.68g were completely dissolved by stirring in 2,006g of DMAc solution under the nitrogen atmosphere, and then BPDA 95.88g and BTDA 70g, as dianhydride, were added thereto, divided by three times.
• the polyamic acid solution was prepared by 24hr stirring. This polyamic acid solution was casted to prepare a film, and raised up to 350°C during 60 minutes and maintained for 30 minutes. The thickness of the film reached to 20 ⁇ m after thermal curing. The measured glass transition temperature was 223°C.
• Diamines of TPER 49.7g and ODA 102.1g were completely dissolved in 2,425g of DMAc solution under the nitrogen atmosphere, and then BPDA 200g as dianhydride was added thereto, divided by three times.
• the polyamic acid solution was prepared by 24hr stirring. This polyamic acid solution was casted to prepare a film, and raised up to 350°C during 60 minutes and maintained for 30 minutes. The thickness of the film reached to 20 ⁇ m after thermal curing. The measured glass transition temperature was 236°C.
• Diamines of TPER 90.7g and PDA 33.55g were completely dissolved by stirring in 2,112g of DMAc solution under the nitrogen atmosphere, and then BPDA 91.3g and BTDA 100g, as dianhydride, were added thereto, divided by three times.
• the polyamic acid solution was prepared by 24hr stirring. This polyamic acid solution was casted to prepare a film, and raised up to 350°C during 60 minutes and maintained for 30 minutes. The thickness of the film reached to 20 ⁇ m after thermal curing. The measured glass transition temperature was 252°C.
• the polyamic acid solution prepared in Preparation Example 2 was coated on both sides of a plasma treated polyimide film (A) with a thickness of 38 ⁇ m.
• the thickness of one side casted polyamic acid on polyimide film was determined by final thickness after thermal curing of this polyamic acid film, which would be 6 ⁇ m.
• polyamic acid films on the polyimide film were formed by hot-air drying in a chamber with 130°C.
• the polyamic acid films were changed to thermoplastic polyimide films through thermal imidization process. This thermal imidization process was conducted that the temperature was raised from 150°C to 395°C at a rate of 20°C/min for 9 minutes under the nitrogen atmosphere.
• thermoplastic polyimide coated polyimide film was inserted between electrodeposited (ED) copper foils with a thickness of 12 ⁇ m.
• the double-sided metal clad laminate was manufactured by attaching the ED copper foil on both sides of thermoplastic polyimide coated polyimide film using high temperature thermal lamination with 100 kgf/cm pressure.
• a double-sided metal clad laminate was manufactured by performing the same process as Example 1 except that a roll and annealed (RA) copper foil with a thickness of 18 ⁇ m was used.
• RA roll and annealed
• a double-sided metal clad laminate was manufactured by performing the same process as Example 1 except that a roll and annealed copper foil with a thickness of 18 ⁇ m was used and the polyamic acid solution prepared in Preparation Example 1 was used.
• a double-sided metal clad laminate was manufactured by performing the same process as Example 1 except that a polyimide film (B) having different mechanical and thermal properties compared with the polyimide film used in Example 1 was used and an electrodeposited copper foil with a thickness of 18 ⁇ m was used.
• a double-sided metal clad laminate was manufactured by performing the same process as Example 4 except that a roll and annealed copper foil with a thickness of 12 ⁇ m was used and the polyamic acid solution prepared in Preparation Example 3 was used.
• a double-sided metal clad laminate was manufactured by performing the same process as Example 1 except that a polyimide film (C) having different mechanical and thermal properties compared with the polyimide film used in Example 1 was used.
• a double-sided metal clad laminate was manufactured by performing the same process as Example 1 except that a polyimide film (D) having different mechanical and thermal properties compared with the polyimide film used in Example 1 was used.
• the polyamic acid solution prepared in Preparation Example 1 was coated on both sides of a plasma treated polyimide film (E) with a thickness of 50 ⁇ m.
• the thickness of one side casted polyamic acid on polyimide film was determined by final thickness after thermal curing of this polyamic acid film, which would be 3 ⁇ m.
• polyamic acid films on the polyimide film were formed by hot-air drying in a drying chamber with 130°C.
• the polyamic acid films were changed to thermoplastic polyimide films through thermal imidization process. This thermal imidization process was conducted that the temperature was raised from 150°C to 395°C at a rate of 20°C/min for 9 minutes under the nitrogen atmosphere.
• thermoplastic polyimide coated polyimide film was inserted between electrodeposited (ED) copper foils with a thickness of 35 ⁇ m.
• the double-sided metal clad laminate was prepared by attaching the ED copper foil on both sides of thermoplastic polyimide coated polyimide film using high temperature thermal lamination with 100 kgf/cm pressure.
• a double-sided metal clad laminate was prepared by conducting the same process as Example 8 except that an electrodeposited (ED) copper foil with a thickness of 12 ⁇ m was used.
• ED electrodeposited
• a double-sided metal clad laminate was manufactured by performing the same process as Example 8 except that a roll and annealed copper foil with a thickness of 18 ⁇ m was used.
• a double-sided metal clad laminate was manufactured by performing the same process as Example 8 except that a polyimide film (F) having a thickness of 50 ⁇ m and different mechanical and thermal properties compared with the polyimide film used in Example 8 was used and a roll and annealed copper foil with a thickness of 35 ⁇ m was used.
• F polyimide film
• a double-sided metal clad laminate was manufactured by performing the same process as Example 8 except that a polyimide film (G) having a thickness of 50 ⁇ m and different mechanical and thermal properties compared with the polyimide film used in Example 8 was used and a roll and annealed copper foil with a thickness of 12 ⁇ m was used.
• G polyimide film
• Table 2 showed appearance defects occurring when a thick layer polyimide copper clad laminate was manufactured by using each polyimide film in Table 1 and dimensional stability.
• high quality metal clad laminate can be prepared by lamination method. That is to say, when polyimide film has an elongation of 30% or less, a tensile modulus of 3GPa or more, and a coefficient of thermal linear expansion (CTE) of 5 to 30ppm/°C, which is calculated from 100 to 250°C, it is possible to laminate a metal foil by a lamination method.
• CTE coefficient of thermal linear expansion

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• 2010
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