CN102131345A - Metalized polyimide film and flexible circuit board with the same - Google Patents
Metalized polyimide film and flexible circuit board with the same Download PDFInfo
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- CN102131345A CN102131345A CN201010141682XA CN201010141682A CN102131345A CN 102131345 A CN102131345 A CN 102131345A CN 201010141682X A CN201010141682X A CN 201010141682XA CN 201010141682 A CN201010141682 A CN 201010141682A CN 102131345 A CN102131345 A CN 102131345A
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- 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
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- 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
- B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
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- 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
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
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- 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
- B32B2311/12—Copper
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- 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
- B32B2311/22—Nickel or cobalt
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- 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
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- 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
- B32B2457/08—PCBs, i.e. printed circuit boards
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- Microelectronics & Electronic Packaging (AREA)
- Laminated Bodies (AREA)
Abstract
The present invention provides a metalized polyimide film which can be used for obtaining a flexible circuit board with an extensibility that is reduced for 50% compared with that of the prior-art flexible circuit board in an OLB (outer lead bonding) step, and a flexible circuit board with the film. The invention is provided according to the metalized polyimide film, etc. The invention is characterized in that: the metalized polyimide film is formed through directly setting a metal film on the polyimide film through a plating method. When the thickness of the polyimide film is 35-40 mu m, the water absorption is 1wt%-3wt%. Furthermore a thermal expansion coefficient in a TD direction (width direction) is 3-8ppm/DEG C, and the thermal expansion coefficient in a MD direction (length direction) is 9-15ppm/DEG C.
Description
Technical field
The present invention relates to metallized polyimide film and the flexible PCB that uses it, in more detail, the present invention relates to following metallized polyimide film and the flexible PCB that uses it, the elongation when this metallized polyimide film can obtain OLB (lead wire bonding) operation reduces by 50% flexible PCB than existing product.
Background technology
The substrate that forms electronic circuit and these electronic units are installed comprise " the lead wire circuit plate " of hardboard shape and film like and have flexibility, can free bend " flexible PCB " (below, be also referred to as FPC sometimes).Wherein, FPC is owing to apply flexibly its flexibility, can in lcd driver (driver) requires the part of bendability like that with the hinge portion of circuit board, hard disk drive (HDD), Digital video disc (DVD) module, mobile phone, use, so its demand is increasing gradually.
, this flexible PCB uses the base material that is provided with metal level on the surface of polyimide film, by relief method or semi-additive process this metal level is processed, thereby is obtained circuit.In passing the situation that obtains flexible PCB by relief method is described, at first, on the layer on surface of metal of base material, resist layer is set, on this resist layer, places mask with specified circuit pattern, expose, develop by irradiation ultraviolet radiation on it, acquisition is used for the etching mask of etch metal layers, and then, the metal part that exposes is removed in etching, then remove residual resist layer, washing if desired, is carried out specific plating on the conductor terminal of circuit part etc.
Under situation about obtaining by semi-additive process, 1 dose of layer against corrosion is set in the metal surface of base material, on this resist layer, place mask with specified circuit pattern, expose by irradiation ultraviolet radiation on it, develop, acquisition is used for the plating mask in the layer on surface of metal electro-coppering, the metal level that opening portion exposes is electroplated as negative electrode, form circuit part, remove resist layer then, carry out soft etching, remove the metal level of circuit part above-mentioned substrate surface in addition, thereby finish circuit part, washing if desired, is carried out specific plating on the conductor terminal of circuit part etc.
Now, that LCD (below, be also referred to as LCD sometimes), mobile phone, digital camera and various electrical equipment all require is frivolous, small-sized, lightweight quantizes, cost degradation, and the electronic unit of An Zhuaning is also carrying out the trend of miniaturization certainly therein.As a result, requiring the circuit spacing of the flexible PCB of use is below the 25 μ m.
In order to satisfy this requirement, needing to obtain the circuit spacing is the flexible PCB of 25 μ m, obtaining by relief method under the situation of circuit, because the influence that produces is carved in the lateral erosion when not having circuit to make, therefore in order to obtain the good circuit of cross section rectangular shape, be necessary for below the 20 μ m in the above-mentioned metal layer thickness that is provided with on the base material.In addition, when obtaining circuit by semi-additive process, above-mentioned metal layer thickness is necessary for several μ m.
Method as obtaining this base material is recommended on the insulative resin film surface, obtains metallic film by dry plating, obtains the copper film by dry plating thereon, by the wet method plating copper film is set thereon, thereby obtains the method for metal level.This is because this base material obtains whole formation films by the plating method, therefore can control metal layer thickness arbitrarily.
In addition, in the circuit fine pitchization, also require to improve the tack of metal level and insulating properties film.This is because when semiconductor element is installed in flexible PCB, the electrode of semiconductor component surfaces and the circuit inside conductor bonding that partly goes between, but in order to shorten production time per piece at this moment, the bonding that goes between of need at high temperature exerting pressure.
In LCD, because the fine pitchization of circuit, therefore during OLB (lead wire bonding) operation in being connected of the glass substrate of LCD and COF (covering brilliant film), need use ACF (anisotropic conducting film) bonding.ACF is the film of pick-up metal particulate in thermosetting resin, in the position of carrying out OLB, glass substrate by LCD and COF seize on both sides by the arms and heat and pressurize, thus, the overlapping contact of metal particle in the ACF, only on compression aspect, can guarantee conductivity, on the other hand, between the circuit on the glass substrate and can guarantee the insulating properties of AFC between the circuit on the COF.
When this OLB (lead wire bonding) operation, AFC heats in 150 ℃～200 ℃ scope, pressurizes under the pressure more than the 1MPa.Therefore, under this condition,, then can't guarantee conductivity, the insulating properties stipulated, so the dimensional stability of COF is extremely important if the size of COF changes.
In addition, the adhesive strength of improving the metal level that is provided with on polyimide film and this surface is to develop the research topic that has not stopped since this base material, has carried out a large amount of tests.
Therefore, the applicant has proposed to use and has comprised pyromellitic acid dianhydride (PMDA) and 4,4 '-diaminodiphenyl ether (ODA) is as principal component, or contain by pyromellitic acid dianhydride (PMDA) and 4, the composition that 4 '-diaminodiphenyl ether (ODA) constitutes and by bibenzene tetracarboxylic dianhydride (BPDA) and 4, the composition that 4 '-diaminodiphenyl ether (ODA) constitutes is as the polyimide film of principal component, by plasma treatment is carried out on this polyimide film surface, upgrading is carried out in corona discharge or wet treatment, thereby import the hydrophilic functional group on this surface, make the thickness of this upgrading layer be
Below, thereon by sputtering method, adopt the metallic that is selected from nickel, chromium and alloy thereof at least layer that makes preparations for sowing, the copper layer of thickness 8 μ m is set by the plating method thereon, thereby prepares the method (referring to the 1st, 2 pages of patent documentations 1) of 2 layers of plating coating copper polyimide substrate.
By this method, the initial stage adhesive strength of the polyimide surface of gained base material and metal level is under 150 ℃, in atmosphere, place after 168 hours and the adhesive strength after carrying out 100 hours PCT test under 121 ℃, humidity 95%, 2 atmospheric pressure is value (referring to the 5th page of patent documentation 1) excellent like this more than the 400N/m.
In addition, proposed excellent in dimensional stability, be suitable for fine pitch circuit substrate, especially on the thin-film width direction with the polyimide film of the COF (covering brilliant film) of thin space distribution with cover copper laminated body (patent documentation 2) used as base material.Wherein, put down in writing to be desirably in and used 4 more than the specified quantitative in two amine components, 4 '-diaminobenzene formailide, from the viewpoint of dimensional stability, the thermal coefficient of expansion of regulation polyimide film makes thermal coefficient of expansion consistent with the thermal coefficient of expansion of metal.In the circuit substrate that uses metallized polyimide film, not only require dimensional stability, also require adhesive strength.Yet in patent documentation 2, for not record of adhesive strength, metallized polyimide is not the material that can have both dimensional stability and tack.
[prior art document]
[patent documentation]
[patent documentation 1] TOHKEMY 2007-318177 communique (referring to the 1st, 2,5 page)
[patent documentation 2] TOHKEMY 2009-67859 communique
Summary of the invention
In view of above-mentioned prior art problems point, the purpose of this invention is to provide a kind of can the acquisition when carrying out OLB operation (lead wire bonding), elongation is than the metallized polyimide film and the flexible PCB that uses it of the flexible PCB of existing product reduction by 50%.
The inventor is in order to solve above-mentioned problem, carried out various research, found that if use when thickness is 35 μ m～40 μ m, thermal coefficient of expansion is 3ppm/ ℃～8ppm/ ℃ in TD direction (Width), in MD direction (than length direction) is the specific metallization polyimide film of 9ppm/ ℃～15ppm/ ℃, then can obtain the initial stage adhesion strength and have more than the 600N/m, when the OLB operation, elongation is reduced to 50% circuit substrate of existing product, thereby finishes the present invention.
Promptly, according to the 1st invention of the present invention, a kind of metallized polyimide film is provided, this metallized polyimide film is on the surface of polyimide film metal film to be set directly by the plating method to form, it is characterized in that: when this polyimide film was 35 μ m～40 μ m at thickness, water absorption rate was 1 quality %～3 quality %, and, thermal coefficient of expansion is 3ppm/ ℃～8ppm/ ℃ in TD direction (Width), is 9ppm/ ℃～15ppm/ ℃ in MD direction (than length direction).
In addition, according to the 2nd invention of the present invention, a kind of metallized polyimide film is provided, it is characterized in that, in above-mentioned the 1st invention, the humidity expansion coefficient of above-mentioned polyimide film is 7ppm/%HR～13ppm/%HR in TD direction (Width), is 12ppm/%HR～15ppm/%HR in MD direction (than length direction).
In addition, according to the 3rd invention of the present invention, a kind of metallized polyimide film is provided, it is characterized in that, in the above-mentioned the 1st or the 2nd invention, above-mentioned polyimide film contains the imide bond that is formed by bibenzene tetracarboxylic and diamine compound in polyimide molecule, when measuring (Cu K α incidence angle=0.1 °) its surperficial TD direction (Width) by the film X-ray diffraction method, in each scope of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 °, has halfwidth and is the peak below 1.5 °.
In addition, according to the 4th invention of the present invention, a kind of metallized polyimide film is provided, it is characterized in that, in above-mentioned the 3rd invention, above-mentioned metal film is made of a kind that is selected from nickel, chromium or nickel alloy underlying metal film that forms and the copper layer that is arranged on this underlying metal film at least.
In addition, according to the 5th invention of the present invention, provide a kind of metallized polyimide film, it is characterized in that, in above-mentioned the 4th invention, above-mentioned copper layer is the copper film.
In addition,, provide a kind of metallized polyimide film, it is characterized in that, in above-mentioned the 4th invention, in above-mentioned copper layer, on the surface of copper film, also be laminated with copper film according to the 6th invention of the present invention.
In addition,, provide a kind of metallized polyimide film, it is characterized in that in the above-mentioned the 5th or the 6th invention, above-mentioned metallic film and copper film form by dry plating according to the 7th invention of the present invention.
In addition,, provide a kind of metallized polyimide film, it is characterized in that in the above-mentioned the 6th or the 7th invention, above-mentioned copper film forms by the wet method plating according to the 8th invention of the present invention.
In addition, according to of the present invention the 9th the invention, a kind of metallized polyimide film is provided, it is characterized in that, above-mentioned the 1st～the 8th the invention each in, the thickness of above-mentioned metal film is below the 20 μ m.
In addition, according to the 10th invention of the present invention, a kind of flexible PCB is provided, in this circuit board, on the surface of polyimide film, be provided with the circuit pattern of metal film, it is characterized in that: aforementioned polyimide film contains the imide bond that is formed by bibenzene tetracarboxylic and diamine compound in polyimide molecule, when measuring (Cu K α incidence angle=0.1 °) its surperficial TD direction by the film X-ray diffraction method, in 2 θ=12 °～18 °, 2 θ=26 °～32 °, in each scope of 2 θ=42 °～48 °, has halfwidth and is the peak below 1.5 °.
In addition, according to the 11st invention of the present invention, a kind of flexible PCB is provided, it is characterized in that, in above-mentioned the 10th invention, above-mentioned metal film is made of a kind that is selected from nickel, chromium or nickel alloy underlying metal film that forms and the copper layer that is arranged on this underlying metal film at least.
In addition,, provide a kind of flexible PCB, it is characterized in that in the above-mentioned the 10th or the 11st invention, the thickness of above-mentioned metal film is below the 20 μ m according to the 12nd invention of the present invention.
In addition, according to the 13rd invention of the present invention, a kind of flexible PCB is provided, it is characterized in that, in the above-mentioned the 10th～the 12nd each invention, remove the aforementioned metal rete in etching, when exposing the film surface after the circuit fabrication, measure the TD direction on (Cu K α incidence angle=0.1 °) polyimide film surface by the film X-ray diffraction method, in each scope of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 °, have halfwidth and be the peak below 1.5 °.
In addition, according to the 14th invention of the present invention, provide a kind of flexible PCB, it is characterized in that, the metallized polyimide film that uses the 1st～the 9th each invention to be put down in writing processes by relief method or semi-additive process.
Metallized polyimide film of the present invention is because when thickness is 35 μ m～40 μ m, thermal coefficient of expansion is 3ppm/ ℃～8ppm/ ℃ in TD direction (Width), in MD direction (than length direction) is 9ppm/ ℃～15ppm/ ℃, less, therefore can be reduced to below 50% of existing product by the elongation when carrying out OLB (lead wire bonding) operation, have initial stage bonding density and be the above such characteristic of 600N/m, can obtain to have the flexible PCB of the circuit part of fine pitch.Therefore, by using this metallized polyimide film, even the line bonding operation under the high temperature that requires in the present fitting operation also can fully meet the requirements, industrial value of the present invention is very high.
Description of drawings
Fig. 1 is the spectrogram of the film X-ray diffraction of the TD direction of the polyimide film of use in the embodiment of the invention 1.
Fig. 2 is in the present invention (embodiment 1) COF, to not covering metal level, exposes the spectrogram that film X-ray diffraction that the polyimides face carries out the TD direction obtains.
Fig. 3 is the skeleton diagram of expression metallized polyimide film structure of the present invention.
Fig. 4 is the skeleton diagram of expression other structures of metallized polyimide film of the present invention.
Embodiment
Below, use accompanying drawing, metallized polyimide film of the present invention, flexible PCB and their manufacture method are elaborated.
1. metallized polyimide film
Metallized polyimide film of the present invention is the metallized polyimide film that metal film directly is set on the surface of polyimide film by the plating method, above-mentioned polyimide film is characterised in that, when thickness is 35 μ m～40 μ m, water absorption rate is 1 quality %～3 quality %, and, thermal coefficient of expansion is 3ppm/ ℃～8ppm/ ℃ in TD direction (Width), is 9ppm/ ℃～15ppm/ ℃ in MD direction (than length direction).
In addition, metallized polyimide film of the present invention is direct on the surface of the specific polyimide film of following detailed description, does not promptly form metal film by adhesive.Metal film constitutes by underlying metal film with at the surperficial copper layer that is provided with of underlying metal film.The copper layer constitutes by the copper film or by copper film and copper film.Promptly, metallized polyimide film of the present invention is not use adhesive that the duplexer of metal film just is set on the surface of polyimide film 1, and metal film is the stepped construction (referring to Fig. 3) or the underlying metal film 2 of underlying metal film 2 and copper film 3 that constitutes the copper layer and copper film 4 and the stepped construction (referring to Fig. 4) that constitutes the copper film 3 of copper layer.
2. polyimide film
When the polyimide film that uses among the present invention was 35 μ m～40 μ m at thickness, water absorption rate was 1 quality %～3 quality %.
Surface at polyimide film forms underlying metal film and copper film by dry plating, and then, by the wet method plating, especially galvanoplastic form under the situation of specific thickness copper film, form the tensile stress of electrostatic stress form in copper film.This tensile stress is the reason that metal film and polyimide layer are peeled off.
When by the wet method plating copper film being set, polyimide film is dipping in plating is bathed.The water absorption of polyimide film is good, if flood in plating is bathed, then can absorb water expands.In addition, owing to after plating finishes, carry out heat drying, therefore can shrink the state that is returned to before plating is handled.Therefore, as long as because the speed of expansion that the polyimide film suction causes is suitable, then can finish copper film on the surface of the polyimide film that suitably expands, pass through heat drying then, polyimide film shrinks, can prolong copper film, thereby reduce in copper film with the residual tensile stress of internal stress form.
In addition, in the present invention, except the speed of expansion that causes, also must consider water absorption rate because polyimide film absorbs water.In the present invention, using water absorption rate is the polyimide film of 1～3 quality %, if water absorption rate less than 1 quality %, then the swell increment of the polyimide film that is caused by suction is less, can't realize purpose of the present invention.If water absorption rate surpasses 3 quality %, then because the swell increment that the suction of polyimide film causes is excessive, under the situation of heat drying, in the copper layer, compression stress can be produced as internal stress, enough initial stage adhesive strengths and PCT adhesive strength can't be obtained sometimes.
In addition, have as above-mentioned absorptive reason, can consider as follows as polyimide film.
Usually, known polyimide film is because crystallization takes place in its thermal endurance and forming method easily.In the polyimide film of crystallization, the polyimide molecule proper alignment passes in and out moisture easily between this molecule and the molecule.That is, in the polyimides of suitable crystallization, using thickness is the polyimide film of 35 μ m～40 μ m, and can make water absorption rate is 1～3 quality %.
In order to confirm whether crystallization of polyimide film, can carry out the film X-ray diffraction method to the polyimide film surface and measure.Under the situation of crystallization, its crystallization degree is also inconsistent, and usually, a plurality of peaks can be confirmed on spectrogram.In the present invention, if measure TD direction (Width), then as shown in fig. 1, preferably in each scope of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 °, has halfwidth and is the peak below 1.5 °.The number at peak is as long as there is 1 in scope separately.This is because so long as the crystallization polyimide film of this degree, it is exactly the polyimide film that the present invention has the suitable water absorption rate and the coefficient of expansion, as a result, by on metallized polyimide film, processing, thereby can guarantee the adhesive strength expected and the dimensional stability of COF.
In addition, in the polyimide film that the present invention uses, measure (Cu K α incidence angle=0.1 °) if carry out the film X-ray diffraction method in TD direction (Width), then preferably not have halfwidth be peak below 1.5 ° to the position below 2 θ=11 °.In present polyimide film, if carry out same mensuration, then to have halfwidth be peak below 1.5 ° to the position below 2 θ=11 °, the film that uses in metallized polyimide film of the present invention demonstrates by the elongation technology in the improved thin film film formation process, thereby can realize the speciality of low-thermal-expansion.Specifically, use and present same raw material, by changing the mixed proportion of raw material, and in film formation process, embody anisotropy, thereby can improve elongation technology, in addition, by glass transition temperature is also risen to about Tg:350 ° from about Tg:320 ° of existing product, be controlled near silicon and glass 3ppm/ ℃～8ppm/ ℃ by the thermal coefficient of expansion that makes TD direction (Width), if measure (Cu K α incidence angle=0.1 °) thereby carry out the film X-ray diffraction method in TD direction (Width), then obtaining position below 2 θ=11 °, not have halfwidth be the polyimide film at the peak below 1.5 °.
By adopting this polyimide film, owing to can suppress because circuit and the LSI that the heating of bonding process causes, or the departing from or be offset of mutual alignment between circuit and glass, therefore can be high-precision bonding, the possibility raising of promotion productivity ratio raising.If this is to measure (Cu K α incidence angle=0.1 °) because existing product is carried out the film X-ray diffraction method on TD direction (Width), then, therefore there is the big such problem of deviation of carrying out elongation in the OLB bond sequence by orientation because the position below 2 θ=11 ° has halfwidth is peak below 1.5 °.
Polyimide film can directly be provided with metal level on the surface, at this moment, the coefficient of thermal expansion differences of metal level and polyimide film is big more, and the heat during online bonding causes producing load on the circuit part of narrow width and the polyimide film bonding face, just easy peeling off more.Therefore, in order to avoid this problem, the thermal coefficient of expansion of used polyimide film is necessary for 3ppm/ ℃～8ppm/ ℃ in the TD direction, is necessary for 9ppm/ ℃～15ppm/ ℃ in the MD direction.By in this scope, thereby directly be provided with on the polyimide film surface under the situation of metal level,, also be difficult to produce and peel off even the heat during online bonding causes producing load on the circuit part of narrow width and the polyimide film bonding face.
In addition, humidity expansion coefficient is 7ppm/%HR～13ppm/%HR in the TD direction, is 12ppm/%HR～15ppm/%HR in the MD direction.This is because so long as the polyimide film of humidity expansion coefficient in this scope, just can be by being processed into metallized polyimide film, thus guarantee the adhesive strength expected and the dimensional stability of COF.
As the polyimide film that uses among the present invention, as long as have above-mentioned characteristic, in addition, just there is no particular limitation.As described later, preferably use with the polyimide film of bibenzene tetracarboxylic as principal component.Be that the polyimide film of principal component is because therefore thermal endurance, excellent in dimensional stability be preferred with the bibenzene tetracarboxylic.
The thickness of the polyimide film that uses among the present invention has no particular limits, but the qualification rate when considering to guarantee bendability and metal film forming is 25～50 μ m, is preferably 25～45 μ m.
In addition, in order to improve the various characteristics of films such as sliding, heat conductivity, can also use the product that adds filler.In this case, be silicon dioxide, titanium oxide, aluminium oxide, silicon nitride, boron nitride, calcium monohydrogen phosphate, calcium phosphate, mica etc. preferably as the material of filler.
The particle diameter of the filler filling kind of the film characteristics of upgrading and interpolation as required is different, and there is no particular limitation, and average grain diameter is 0.05～100 μ m usually, is preferably 0.1～75 μ m, and more preferably 0.1～50 μ m is preferably 0.1～25 μ m especially.If particle diameter is lower than this scope, then be difficult to embody the effect of upgrading, if exceed this scope, then probably can damage surface characteristic significantly, reduce mechanical property greatly.
In addition, because the addition of filler is also by the decisions such as particle diameter of film characteristics that needs upgrading and filler, therefore there is no particular limitation.Usually, with respect to 100 weight portion polyimides, the addition of filler is 0.01～100 weight portion, is preferably 0.01～90 weight portion, more preferably 0.02～80 weight portion.If the filler addition is lower than this scope, then be difficult to embody because the upgrading effect that filler obtains if surpass this scope, then probably can be damaged the mechanical property of film greatly.
As the example of this polyimide film, can enumerate for example KAPTON 150EN-A (registered trade mark) of You East レ デ ユ Port Application Co., Ltd. sale.
2. the manufacture method of polyimide film
The polyimide film that uses among the present invention is unqualified to its manufacture method, can the following method of illustration: at first make the polyamic acid as precursor, be converted to polyimides then, carry out filming again.
(1) as the manufacturing of the polyamic acid of precursor
In order to obtain polyamic acid, the method that can use known method and their are made up.As representational polymerization, can be listed below the method for (a)～(e).That is,
(a) in organic polar solvent, dissolve aromatic diamine, carry out polymerization to wherein adding equimolar aromatic tetracarboxylic acid's dianhydride.
(b) in organic polar solvent, make the less aromatic diamine compound reaction of aromatic tetracarboxylic acid's dianhydride and relative its mole, obtain to have the prepolymer of anhydride group at two ends.Then, add aromatic diamine compound and carry out polymerization, finally make the first-class substantially mole of aromatic tetracarboxylic acid's dianhydride and aromatic diamine compound.
(c) in organic polar solvent, make the more aromatic diamine compound reaction of aromatic tetracarboxylic acid's dianhydride and relative its mole, obtain to have amino prepolymer at two ends.Then, add aromatic tetracarboxylic acid's dianhydride compound and carry out polymerization, finally make the first-class substantially mole of aromatic tetracarboxylic acid's dianhydride and aromatic diamine compound.
(d) in organic polar solvent, behind dissolving and/or the dispersion aromatic tetracarboxylic acid dianhydride, add equimolar basically aromatic diamine compound, carry out polymerization.
(e) in organic polar solvent, make the mixture reaction of equimolar basically aromatic tetracarboxylic acid's dianhydride and aromatic diamine, carry out polymerization.
In order to obtain polyamic acid, can use any method of this (a)～(e), also can partly be used in combination.All can be by the polyamic acid that arbitrary method obtains as the raw material of used polyimide film among the present invention.
In addition, as above-mentioned acid dianhydride, comprise pyromellitic acid dianhydride, 2,3,6,7-naphthalenetetracarbacidic acidic dianhydride, 3,3 ', 4,4 '-bibenzene tetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarbacidic acidic dianhydride, 2,2 ', 3,3 '-bibenzene tetracarboxylic dianhydride, 3,3 ', 4,4 '-benzophenone tetracarboxylic dianhydride (BTDA), 4,4 '-oxo O-phthalic acid dianhydride, 2,2-two (3,4-dicarboxyl phenyl) propane dianhydride, 3,4,9,10-perylene tetracarboxylic acid dianhydride, two (3,4-dicarboxyl phenyl) propane dianhydride, 1, two (2,3-dicarboxyl phenyl) the ethane dianhydrides of 1-, 1,1-two (3,4-dicarboxyl phenyl) ethane dianhydride, two (2,3-dicarboxyl phenyl) methane dianhydride, two (3,4-dicarboxyl phenyl) ethane dianhydride, the oxydiphthalic acid dianhydride, two (3,4-dicarboxyl phenyl) sulfone dianhydride, TOPOT 2,2 (trimellitic acid monoesters acid anhydrides), ethylenebis (trimellitic acid monoesters acid anhydrides), bisphenol-A two (trimellitic acid monoesters acid anhydrides) and their analogs, the preferred mixture that uses or use arbitrary proportion separately of these materials.
In these acid dianhydrides, especially preferably use pyromellitic acid dianhydride and/or 3,3 ', 4,4 '-bibenzene tetracarboxylic dianhydride and/or 4,4 '-oxo O-phthalic acid dianhydride, and/or 3,3 ', 4,4 '-bibenzene tetracarboxylic dianhydride, more preferably use and contain 3,3 ', 4, the mixture of the acid dianhydride of 4 '-bibenzene tetracarboxylic dianhydride.
As above-mentioned aromatic diamine compound; can enumerate 4; 4 '-diamino-diphenyl propane; 4; 4 '-diaminodiphenyl-methane; benzidine; 3; 3 '-dichloro-benzidine; 3; 3 '-dimethylbenzidine; 2; 2 '-dimethylbenzidine; 3; 3 '-dimethoxy benzidine; 2; 2 '-dimethoxy benzidine; 4; 4 '-diamino-diphenyl thioether; 3; 3 '-diamino diphenyl sulfone; 4; 4 '-diamino diphenyl sulfone; 4; 4 '-oxo diphenylamines; 3; 3 '-oxo diphenylamines; 3; 4 '-oxo diphenylamines; 1; the 5-diaminonaphthalene; 4; 4 '-diamino-diphenyl diethylsilane; 4; 4 '-diamino-diphenyl silane; 4,4 '-diamino-diphenyl ethyl sulfinyl oxide; 4,4 '-diamino-diphenyl N-methylamine; 4; 4 '-diamino-diphenyl N-aniline; 1; 4-diaminobenzene (P-pHENYLENE dI AMINE); 1, the 3-diaminobenzene; 1, the 2-diaminobenzene; two { 4 (4-amino-benzene oxygen) phenyl } sulfone; two { 4 (3-amino-benzene oxygen) phenyl } sulfone; 4; 4 '-two (4-amino-benzene oxygen) biphenyl; 4; 4 '-two (3-amino-benzene oxygen) biphenyl; 1, two (3-amino-benzene oxygen) benzene of 3-; 1, two (4-amino-benzene oxygen) benzene of 3-; 1; two (4-amino-benzene oxygen) benzene of 3-; 1; two (3-amino-benzene oxygen) benzene of 3-; 3,3 '-diaminourea benzophenone; 4,4-diaminourea benzophenone and their analog etc.
The polyamic acid that the polyimide film that uses among the present invention is used can be by selecting kind, the mixing ratio of aromatic acid tetracarboxylic dianhydride and aromatic diamine in the above range, and polymerization obtains then.
Be used for the preferred solvent of synthesizing polyamides acid so long as can dissolve the solvent of polyamic acid, just can use material arbitrarily.The preferred amide kind solvent, i.e. N, dinethylformamide, N, N-dimethylacetylamide, N-N-methyl-2-2-pyrrolidone N-etc., preferred especially N, dinethylformamide, N, N-dimethylacetylamide.
(2) be converted into polyimides and filming by polyamic acid
Then, the organic solution that will comprise thus obtained polyamic acid casts on the supports such as glass plate, aluminium foil, metallic tape loop, metallic cylinder as resin molding.At this moment, by on support, heating, thus can be partly solidified and/or dry, at this moment, so long as give hot blast or far-infrared radiation heat gets final product.In addition, can also directly heat support self.In addition, can make up method that gives hot blast or far-infrared radiation heat and the method that directly heats support self.
Resin molding by the heating casting is the semi-solid preparation film with self-supporting, and so-called gel film can be peeled off by support.This gel film is the interstage that is solidified into polyimides by polyamic acid, promptly has self-supporting by the part imidizate, has residual volatile ingredients such as solvent.
Then, heat above-mentioned gel film, dry to remove residual solvent, finish curing (imidizate) simultaneously, in order to avoid the contraction of dry and gel film when solidifying, can be fixed on the stenter framework with the end with gel film such as safety pin or stenter clamp, be delivered in the heating furnace, 200～400 ℃ of heating down, obtain polyimide film.
3. metallized polyimide film and manufacture method thereof
Metallized polyimide film of the present invention can be direct on the specific polyimide film surface as above-mentioned acquisition, promptly need not adhesive and just form metal film.
Shown in Fig. 3,4, metal film is made of with copper layer 4 underlying metal film 2 and the copper film 3 that is provided with on the surface of underlying metal film 2 or copper film 3.Promptly, metallized polyimide film of the present invention is the duplexer that metal film is not set by adhesive on the surface of polyimide film 1, and metal film is stepped construction or the underlying metal film 2 and the copper film 3 that constitutes the copper layer and the stepped construction of copper layer 4 of underlying metal film 2 and the copper film 3 that constitutes the copper layer.Underlying metal film 2 forms by the plating method with 3 expectations of copper film.In the latter, can after underlying metal film 2 and copper film 3 are set, the copper film 4 of specific thickness be set by the wet method plating.
(a) underlying metal film
Underlying metal film is the film that is used to guarantee polyimide film and reliabilities such as metal film tack and thermal endurance.Therefore, the material of underlying metal film is selected from nickel, chromium and their alloy any in order to improve the adhesive force of polyimide film and copper layer, and easy etching is set out when being prepared by bond strength and circuit, preferred nichrome.In addition, for the concentration gradient of nichrome is set, can also constitute metallic film with the different a plurality of nichrome layers of chromium concn.As long as constitute, just can improve corrosion resistance, the resistance to migration of metallized polyimide film with these metals.
In addition, in order further to improve the corrosion resistance of underlying metal film, can also in above-mentioned metal, add palladium, titanium, molybdenum, cobalt etc.
In addition, before carrying out dry plating,, preferably passing through corona discharge or ion exposure etc. in order to improve the tack of polyimide film and underlying metal film, after the polyimide film surface carried out surface treatment, under the oxygen atmosphere, carry out ultraviolet irradiation and handle.There is no particular limitation to these treatment conditions, can be the condition that adopts in the manufacture method of common metallized polyimide film.
The thickness of above-mentioned underlying metal film is preferably 3～50nm.Not enough 3nm, if the metal level of above-mentioned metallized polyimide film is carried out etching and prepares circuit, then the above-mentioned metallic film of etching solution meeting etch is invaded between polyimide film and the above-mentioned metallic film, circuit can float sometimes, is not preferred.On the other hand, if surpass 50nm, then prepare under the situation of circuit in etching, can't remove metallic film fully, its form with residue remains between circuit, probably can produce the defective insulation between circuit.
Above-mentioned underlying metal film is preferably by the dry plating film forming.In dry plating, comprise sputtering method, magnetron sputtering system, ion plating method, ion beam method, vacuum vapour deposition, CVD method etc., can use arbitrarily, in industry, use magnetron sputtering system.This is because production efficiency is higher.
(b) copper film
In the present invention, stacked copper film preferably forms by dry plating on underlying metal film.The dry plating that adopts can use any of above-mentioned sputtering method, magnetron sputtering system, ion plating method, ion beam method, vacuum vapour deposition, CVD method etc.Can also by magnetron sputtering system with above-mentioned metallic film film forming after, by vapour deposition method above-mentioned copper film is set.That is, can adopt identical above-mentioned metallic film of method dry plating and copper film, also can adopt different dry platings to form.
If the reason of above-mentioned copper film is set is that the resistance of then switching on improves, the current density instability of plating owing to directly by galvanoplastic above-mentioned copper layer is set on above-mentioned metallic film.By above-mentioned copper film is set, thereby can reduce energising resistance, make the current density stabilisation when electroplating.The thickness of this copper film is 10nm～1 μ m, is preferably 20nm～0.8 μ m.If this is that if the energising resistance in the time of then can't fully reducing plating blocked up, then can spend a large amount of time when film forming because thinner than this value, productivity is worsened, economy incurs loss.
(c) copper film
In metallized polyimide film of the present invention, can on the copper film, copper film be set as required.The necessity of copper film suitably determines according to the manufacturing process of flexible PCB.
The thickness of copper film is preferably 1.0～20.0 μ m.If this is that if surpass 20 μ m, then the internal stress of copper film is excessive because less than 1.0 μ m then when forming circuit, can't obtain enough conductivity sometimes.
Copper film preferably is provided with by the wet method plating.In dry plating, the thickness for plating becomes to stipulate requires a great deal of time, and productivity is worsened, and economy incurs loss.In the wet method plating, comprise that galvanoplastic and electroless plating apply method, can use any, also can be used in combination, galvanoplastic are simple, and the gained copper film is careful, are preferred therefore.In addition, the plating condition can be carried out under known condition.
Be provided with under the situation of copper film by galvanoplastic, if use sulfuric acid bath, the electroplating copper film that then can obtain to have suitable tensile stress, flexible by the expansion of polyimide film, can more easily obtain the balance of internal stress, so be preferred.
Obtaining under the state of the internal stress of this copper film before the polyimide film drying, to be preferably the tensile stress of 5～30MPa under the situation of copper film by galvanoplastic.If this is because not enough 5MPa, then when dry polyimide film, the flexible effect of polyimide film is big inadequately, if surpass the tensile stress of 30MPa, the flexible effect of the polyimide film during then dry polyimide film is too small.
Electroplate as long as under common condition by the copper that sulfuric acid bath is carried out.As plating bath, can use the commercially available copper sulphate plating bath of in common copper is electroplated, using.In addition, the average cathode-current density of the preferred coating bath of cathode-current density is 1～3A/dm
2This is because the not enough 1A/dm of the average cathode-current density of cathode-current density
2, the hardness of gained copper film is higher, is difficult to guarantee bendability, even use the gained metallized polyimide film to obtain flexible PCB, the gained flexible PCB also can't become on flexibility well.On the other hand, if be because average cathode-current density surpasses 3A/dm
2, then can produce inhomogeneous in the residual stress that in the gained copper film, produces.
Use the electro-coppering device of sulfuric acid bath identical with the dry plating operation, roll out the polyimide film of roller shape from the machine of rolling out that is arranged on electro-coppering device portal side, carry and also pass through plating coating groove successively, the electroplanting device of the roll-to-roll mode of carrying out when batching with coiling machine, because production efficiency improves, manufacturing cost reduces, and is preferred therefore.In this case, the transporting velocity of film preferably is adjusted into 50～150m/h.If the not enough 50m/h of transporting velocity, then productivity is low excessively, if surpass 150m/h, then needs to improve the electrical current amount, must use large-scale supply unit, has the higher such problem of equipment price.
In thus obtained metallized polyimide film of the present invention, estimate based on JPCABM01-11.5.3 (B method) (peel strength), be that the initial stage adhesive strength is more than the 600N/m, the elongation the when ACF during the OLB operation is bonding is to have the circuit substrate that reduces existing product 50% elongation function below the 0.023mm like this and use its flexible PCB that obtains.
4. flexible PCB and manufacture method thereof
Flexible PCB of the present invention uses metallized polyimide film of the present invention, obtains by relief method or semi-additive process processing.
Above-mentioned metal film is by at least a kind that is selected from nickel, chromium or nickel alloy metallic film that forms, the copper film that on this metallic film, is provided with and the 3 layers of formation of copper layer that are provided with thereon again, and above-mentioned thickness of metal film is below the 20 μ m.
In addition, remove above-mentioned metallic diaphragm in etching, when exposing the film surface after the circuit fabrication, if being carried out the film X-ray diffraction method, the TD direction on polyimide film surface measures (Cu K α incidence angle=0.1 °), then as shown in Figure 2, in each scope of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 °, has halfwidth and is the peak below 1.5 °.The quantity at peak exists in scope separately and gets final product more than 1.Wherein, the peak of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 ° conforms to the peak than the polyimide film of length direction as the metallized polyimide film raw material.
In addition, measure (Cu K α incidence angle=0.1 °) if the TD direction on polyimide film surface is carried out the film X-ray diffraction method, then preferably not have halfwidth be peak below 1.5 ° to the position below 2 θ=11 °.If this is because there is halfwidth in the position below 2 θ=11 ° is peak below 1.5 °, then exist the elongation in the OLB bond sequence to disperse to become big such problem.
In the manufacture method of flexible PCB of the present invention, circuit pattern can obtain by relief method or semi-additive process processing.
For example, when obtaining flexible PCB by null method, can resist layer be set in the metallic film surface of above-mentioned metallized polyimide film of the present invention, exposed mask with predetermined pattern is set thereon, irradiation ultraviolet radiation exposes, develops from it, obtains to be used to obtain the etching mask of circuit part.Then, the metal film that exposes is removed in etching, then removes residual etching mask, washing, the plating of expecting at necessary position, thus obtain flexible PCB of the present invention.
On the other hand, when obtaining flexible PCB by semi-additive process, can resist layer be set in the metallic film surface of above-mentioned metallized polyimide film of the present invention, mask with specified circuit pattern is set thereon, and irradiation ultraviolet radiation exposes, develops, and obtaining with the circuit is the plating mask of opening portion, pass through electrocoppering, separate out copper on the surface of the metal film that exposes opening portion, forming circuit is removed the plating mask then.Then, the metal film beyond the circuit is removed in soft etching, guarantees the insulating properties of circuit, washing, and the plating of expecting at necessary position, thus obtain flexible PCB of the present invention.
The circuit structure of flexible PCB of the present invention all can form the structure that is stacked gradually the metal film that is made of underlying metal film, copper film, copper layer by the polyimide film surface by any preparation of null method or semi-additive process.
In addition, as mentioned above, when making flexible PCB by semi-additive process, the copper layer of metallized polyimide film can suitably be selected only to be made of the copper film, or is made of copper film and copper film.
Embodiment
Below, the present invention will be described in more detail by embodiment, but the present invention is not subjected to any qualification of these embodiment.The condition determination of the film X-ray diffraction that uses among the embodiment in addition,, the conditions such as assay method of adhesive strength are as described below.
(1) film X-ray diffraction method condition determination: as diffraction instrument, use (strain) リ ガ Network manufacture level type X-ray diffraction device SmartLab, on the TD direction, measure with following condition: incidence angle (ω) is 0.1 °, specimen width is 0.1 °, measuring angle 2 θ is 2 °～60 °, and sweep speed is 4 °/minute.
(2) adhesive strength: form line width 1mm by null method, the circuit pattern of length 50mm uses its stretch release method of passing through regulation in JPCA BM01-11.5.3 (B method) (stretch release intensity) to obtain.
(3) water absorption rate: by stipulating in ASTM D570 20 ℃, 24hr infusion process (Immergion) are obtained.
(4) thermal coefficient of expansion: use TMA (Thermal Mechanical Analysis (thermo-mechanical analysis)) device, on the TD direction in 50 °～200 ° scope, obtain by pulling method.
(5) humidity expansion coefficient: the dew point that will control atmosphere gas, the device of energy controlled humidity links to each other with TMA (Thermal Mechanical Analysis (thermo-mechanical analysis)) device, under relative humidity 20,80% atmosphere, measure and extend, calculate humidity expansion coefficient.
(embodiment 1)
At first, preparing water absorption rate is 1.8 quality %, thermal coefficient of expansion is 5ppm/ ℃ in the TD direction, in the MD direction is 11ppm/ ℃, and film X-ray diffraction result can be clear and definite as shown in Figure 1, when 2 θ are 14 °, 29 °, 44 °, have halfwidth respectively and be the peak below 1.0 °, thickness be 38 μ m be the rectangular polyimide film (East レ デ ユ Port Application, KAPTON 150EN-A) of principal component with the bibenzene tetracarboxylic.Its humidity expansion coefficient is 11ppm/%HR in the TD direction, is 12ppm/%HR in the MD direction.
On the one side of this polyimide film, use the sputtering equipment that constitutes by the machine of rolling out, sputter equipment, coiling machine, form average thickness by dc sputtering
Cr is that the chromium-nickel alloy layer of 7 quality % is as metallic film.In addition, on underlying metal film, form average thickness equally
The copper film.
Then, on the copper film, the copper film of thickness 8 μ m is set, obtains metallized polyimide film by the copper galvanoplastic.The electroplating bath that uses is 27 ℃ as the copper sulphate plating bath of copper concentration 23g/l, the bath temperature during plating.In addition, coating bath by machine of rolling out and coiling machine, is carried the polyimide film continuous impregnating in each groove that is provided with metal film in one side for connecting many structures groove of a plurality of coating baths, electroplates simultaneously.Transporting velocity is 75m/h, and the average cathode density of coating bath is adjusted into 1.0～2.5A/dm
2, carry out copper facing.
Obtain the initial stage adhesive strength of gained metallized polyimide film, it is 728N/m, and the elongation the when ACF during the OLB operation engages is the flexible PCB that has the circuit substrate of the function that reduces existing product 50% elongation below the 0.021mm like this and use its acquisition.
Then, use this metallized polyimide film, prepare circuit by relief method and be spaced apart 35 μ m, the whole circuit width is the COF (covering brilliant film) of 15000 μ m.In the relief method operation, carry out etch processes by iron chloride.The IC chip is installed thereon, is used the line bonding apparatus, under 400 ℃, under 0.5 second bonding treatment conditions, the electrode of IC chip surface and the lead portion of circuit are carried out the line bonding.At this moment, the not good ratio of the lead-in wire that produces in inner lead portion and the bonding of polyimide film is 0.0001%.
(embodiment 2)
At first, preparing water absorption rate is 1.7 quality %, thermal coefficient of expansion is 5ppm/ ℃ in the TD direction, in the MD direction is 13ppm/ ℃, and film X-ray diffraction result is peak below 1.0 ° for have halfwidth respectively when 2 θ are 14 °, 29 °, 44 °, thickness is 38 μ m, is the rectangular polyimide film (East レ デ ユ Port Application of principal component with the bibenzene tetracarboxylic, KAPTON 150EN-A).Its humidity expansion coefficient is 9ppm/%HR in the TD direction, is 14ppm/%HR in the MD direction.
On the one side of this polyimide film, use the sputtering equipment that constitutes by the machine of rolling out, sputter equipment, coiling machine, form average thickness by dc sputtering
Cr is that the chromium-nickel alloy layer of 20 quality % is as metallic film.In addition, on metallic film, form average thickness equally
The copper film.
Then, on the copper film,, the copper film of thickness 8 μ m is set, obtains metallized polyimide film by the copper galvanoplastic.The electroplating bath that uses is 27 ℃ as the copper sulphate plating bath of copper concentration 23g/l, the bath temperature during plating.In addition, coating bath by machine of rolling out and coiling machine, is carried polyimide film continuous impregnating in each groove that metal film is set in one side for connecting many structures groove of a plurality of coating baths, electroplates simultaneously.Transporting velocity is 75m/h, and the average cathode-current density of coating bath is adjusted into 1.0～2.5A/dm
2, carry out copper facing.
Obtain the initial stage adhesive strength of gained metallized polyimide film, it is 728N/m, and the elongation the when ACF during the OLB operation engages is the flexible PCB that has the circuit substrate of the function that reduces existing product 50% elongation below the 0.020mm like this and use its acquisition.
Then, use this metallized polyimide film, prepare circuit by relief method and be spaced apart 35 μ m, the whole circuit width is the COF (covering brilliant film) of 15000 μ m.In the relief method operation, carry out etch processes by iron chloride.The IC chip is installed thereon, is used the line bonding apparatus, under 400 ℃, under 0.5 second bonding treatment conditions, the electrode of IC chip surface and the lead portion of circuit are carried out the line bonding.At this moment, the not good ratio of the lead-in wire that produces in inner lead portion and the bonding of polyimide film is 0.0002%.
The polyimide film that use is used in this embodiment 2 forms metallic film, copper film, copper film successively on its surface, remove the metal level of formation by the etching method etching of using iron chloride then.This state is called as the polyimide film that exposes the film surface after the circuit fabrication.This film is carried out X-ray diffraction, obtain the chart of Fig. 2.
The result as shown in Figure 2, the value of finding 2 θ is 14 °, 29 ° and 44 ° and has peak value.Wherein, 14 ° peak is the peak that causes owing to the rectangular polyimide film as the metallized polyimide raw material.
(embodiment 3)
At first, preparing water absorption rate is 1.6 quality %, thermal coefficient of expansion is 5ppm/ ℃ in the TD direction, in the MD direction is 15ppm/ ℃, and film X-ray diffraction result is that peak, thickness below 1.0 ° is 38 μ m, is the rectangular polyimide film (East レ デ ユ Port Application, KAPTON 150EN-A) of principal component with the bibenzene tetracarboxylic for have halfwidth respectively when 2 θ are 14 °, 29 °, 44 °.Its humidity expansion coefficient is 13ppm/%HR in the TD direction, is 15ppm/%HR in the MD direction.
Then, on the one side of this polyimide film, use the sputtering equipment that constitutes by the machine of rolling out, sputter equipment, coiling machine, form average thickness by dc sputtering
Cr is that the chromium-nickel alloy layer of 20 quality % is as metallic film.In addition, on underlying metal film, form average thickness equally
The copper film.
Then, on the copper film,, the copper film of thickness 1 μ m is set, obtains metallized polyimide film by the copper galvanoplastic.The electroplating bath that uses is 27 ℃ as the copper sulphate plating bath of copper concentration 23g/l, the bath temperature during plating.In addition, coating bath by machine of rolling out and coiling machine, is carried polyimide film continuous impregnating in each groove that metal film is set in one side for connecting many structures groove of a plurality of coating baths, electroplates simultaneously.Transporting velocity is 75m/h, and the average cathode-current density of coating bath is adjusted into 1.0～2.5A/dm
2, carry out the copper plating.
Obtain the initial stage adhesion strength of gained metallized polyimide film, it is 728N/m, and the elongation the when ACF during the OLB operation engages is the flexible PCB that has the circuit substrate of the function that reduces existing product 50% elongation below the 0.021mm like this and use its acquisition.
Then, use this metallized polyimide film, prepare by relief method that circuit is spaced apart 35 μ m, the whole circuit width is the COF (covering brilliant film) of 15000 μ m.In the relief method operation, carry out etch processes by iron chloride.The IC chip is installed thereon, is used the line bonding apparatus,, under 0.5 second bonding treatment conditions, the electrode of IC chip surface and the lead portion of circuit are carried out the line bonding at 400 times.At this moment, the not good ratio of the lead-in wire that produces in inner lead portion and the bonding of polyimide film is 0.0001%.
(embodiment 4)
Use the metallized polyimide film that obtains among the embodiment 1, except circuit is spaced apart 25 μ m, prepare flexible PCB similarly to Example 1, obtain the not good ratio of bonding similarly to Example 1.The not good ratio of the bonding of lead and polyimide film is 0.005%, even in fine pitch, enough size reliabilities is arranged also.
(comparative example 1)
Except as polyimide film, using water absorption rate is 1.7 quality %, thermal coefficient of expansion is 16ppm/ ℃ in the TD direction, in the MD direction is 17ppm/ ℃, and humidity expansion coefficient is 13ppm/%HR in the TD direction, is 17ppm/%HR in the MD direction, with the bibenzene tetracarboxylic is principal component, thickness is the polyimide film (East レ デ ユ Port Application production of 38 μ m, KAPTON 150EN) in addition, obtain metallized polyimide film similarly to Example 1.In addition, KAPTON 150EN is carried out the film X-ray diffraction, confirm when 2 θ are 10 ° and 14 °, to exist big peak.In addition, confirm in 2 θ=26 °～32 ° that not having halfwidth in each scope of 2 θ=42 °～48 ° is peak below 1.5 °.
The gained metallized polyimide film is estimated similarly to Example 1, and it is 720N/m that the initial stage is adhered to density, and the elongation during the ACF bonding during the OLB operation is 0.043mm.
Then, except using above-mentioned metallized polyimide film, similarly to Example 1, the flexible PCB of preparation circuit width 35 μ m is obtained the not good ratio of bonding similarly to Example 1.The not good ratio of the bonding that produces in the inner lead portion of circuit is 0.001%, and comparing with embodiment is relatively poor value, even circuit width is 35 μ m, and the circuit board that also can't obtain to have enough reliabilities.
(comparative example 2)
Except circuit is spaced apart 25 μ m,, obtain the not good ratio of bonding similarly to Example 1 with comparative example 1 same preparation flexible PCB.The not good ratio of bonding that produces in the inner lead portion of circuit is 0.1%, under the situation of fine pitchization, can't obtain to have the circuit board of enough reliabilities.
(comparative example 3)
Except as polyimide film, using water absorption rate is 1.4 quality %, thermal coefficient of expansion is 14ppm/ ℃ in the TD direction, in the MD direction is 16ppm/ ℃, and humidity expansion coefficient is 15ppm/%HR in the TD direction, is 16ppm/%HR in the MD direction, with the bibenzene tetracarboxylic is principal component, thickness is that the polyimide film (ProductName, emerging the producing of space portion made UPILEX 35SGA) of 35 μ m in addition, obtains metallized polyimide film similarly to Example 1.In addition, UPILEX 35SGA is carried out the film X-ray diffraction, confirm at θ to be that the position of 11 ° and 14 ° exists big peak.In addition, confirm in 2 θ=26 °～32 ° that not having halfwidth in each scope of 2 θ=42 °～48 ° is peak below 1.5 °.
The gained metallized polyimide film is estimated similarly to Example 1, and to adhere to density be 756N/m for the initial stage for it, and the elongation of the ACF when having the OLB operation when engaging is the circuit substrate of the such function of 0.044mm and the flexible PCB that uses its acquisition.
Then, except using above-mentioned metallized polyimide film, similarly to Example 1, the flexible PCB of preparation circuit width 35 μ m is obtained the not good ratio of bonding similarly to Example 1.The not good ratio of the bonding that produces in the inner lead portion of circuit is 0.001%, and comparing with embodiment is relatively poor value.
(comparative example 4)
Except circuit is spaced apart 25 μ m,, obtain the not good ratio of bonding similarly to Example 1 with comparative example 3 same preparation flexible PCBs.The not good ratio of bonding that produces in the electrode part of circuit is 0.1%, finds can't obtain to have the circuit board of enough reliabilities under the situation of fine pitchization.
" evaluation "
Clear and definite by above embodiment 1～4, PCT adhesive force after metallized polyimide film initial stage adhesive strength of the present invention and the PCT test is very high, therefore use it can prepare the flexible PCB of fine pitch, when in this circuit board, IC being installed, even the line bonding is carried out in pressurization under the temperature more than 400 ℃, lead-in wire can not peeled off from polyimide film yet, as flexible PCB, obtains extreme high reliability.
On the contrary, clear and definite by comparative example 1～4, if use the metallized polyimide film that does not meet condition of the present invention, then in the flexible PCB of fine pitch, or in the existing like this circuit spacing of circuit width 35 μ m, all can't obtain the high flexible PCB of reliability.
Industrial utilizability
Percentage elongation when the ACF when metallized polyimide film of the present invention can be used as initial stage adhesive strength and OLB operation engages is the following like this material of excellent circuit substrate of 0.023mm. If use metallized polyimide film of the present invention to prepare the flexible circuit board of fine pitch, when then in this circuit board, IC being installed, even the line bonding is carried out in pressurization under the temperature more than 400 ℃, lead-in wire can not peeled off from the polyimides film yet, as flexible circuit board, can obtain extreme high reliability. Therefore, the base material used as the flexible circuit board fabrication that requires recently of metallized polyimide film of the present invention is very useful.
Claims (14)
1. metallized polyimide film, this metallized polyimide film is on the surface of polyimide film metal film to be set directly by the plating method to form, it is characterized in that: when this polyimide film is 35 μ m～40 μ m at thickness, water absorption rate is 1 quality %～3 quality %, and, thermal coefficient of expansion is 3ppm/ ℃～8ppm/ ℃ in TD direction (Width), is 9ppm/ ℃～15ppm/ ℃ in MD direction (than length direction).
2. the metallized polyimide film of putting down in writing according to claim 1, it is characterized in that: the humidity expansion coefficient of aforementioned polyimide film is 7ppm/%HR～13ppm/%HR in TD direction (Width), is 12ppm/%HR～15ppm/%HR in MD direction (than length direction).
3. according to claim 1 or 2 metallized polyimide films of being put down in writing, it is characterized in that: aforementioned polyimide film contains the imide bond that is formed by bibenzene tetracarboxylic and diamine compound in polyimide molecule, when measuring (CuK α incidence angle=0.1 °) its surperficial TD direction (Width) by the film X-ray diffraction method, in each scope of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 °, has halfwidth and is the peak below 1.5 °.
4. the metallized polyimide film of putting down in writing according to claim 3 is characterized in that: the aforementioned metal film is made of a kind that is selected from nickel, chromium or nickel alloy underlying metal film that forms and the copper layer that is arranged on this underlying metal film at least.
5. the metallized polyimide film of putting down in writing according to claim 4, it is characterized in that: aforementioned copper layer is the copper film.
6. the metallized polyimide film of putting down in writing according to claim 4 is characterized in that: in aforementioned copper layer.On the surface of copper film, also be laminated with copper film.
7. according to claim 5 or 6 metallized polyimide films of being put down in writing, it is characterized in that: aforementioned metal film and copper film form by dry plating.
8. according to claim 6 or 7 metallized polyimide films of being put down in writing, it is characterized in that: aforementioned copper film forms by the wet method plating.
9. according to each metallized polyimide film of putting down in writing in the claim 1～8, it is characterized in that: the thickness of aforementioned metal film is below the 20 μ m.
10. a flexible PCB in this circuit board, is provided with the circuit pattern of metal film on the surface of polyimide film, it is characterized in that:
Aforementioned polyimide film contains the imide bond that is formed by bibenzene tetracarboxylic and diamine compound in polyimide molecule, when measuring (Cu K α incidence angle=0.1 °) its surperficial TD direction by the film X-ray diffraction method, in each scope of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 °, has halfwidth and is the peak below 1.5 °.
11. the flexible PCB according to claim 10 is put down in writing is characterized in that: the aforementioned metal film is made of a kind that is selected from nickel, chromium or nickel alloy underlying metal film that forms and the copper layer that is arranged on this metallic film at least.
12. according to claim 10 or 11 flexible PCBs of being put down in writing, it is characterized in that: the thickness of aforementioned metal film is below the 20 μ m.
13. according to each flexible PCB of putting down in writing in the claim 10～12, it is characterized in that: remove the aforementioned metal rete in etching, when exposing the film surface after the circuit fabrication, measure the TD direction on (Cu K α incidence angle=0.1 °) polyimide film surface by the film X-ray diffraction method, in each scope of 2 θ=12 °～18 °, 2 θ=26 °～32 °, 2 θ=42 °～48 °, has halfwidth and is the peak below 1.5 °.
14. use each metallized polyimide film of putting down in writing in the claim 1～9, the flexible PCB that processes by relief method or semi-additive process.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010005546A JP5347980B2 (en) | 2010-01-14 | 2010-01-14 | Metallized polyimide film and flexible wiring board using the same |
| JP2010-005546 | 2010-01-14 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102131345A true CN102131345A (en) | 2011-07-20 |
| CN102131345B CN102131345B (en) | 2014-11-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010141682.XA Active CN102131345B (en) | 2010-01-14 | 2010-03-29 | Metalized polyimide film and flexible circuit board with the same |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP5347980B2 (en) |
| KR (1) | KR101702128B1 (en) |
| CN (1) | CN102131345B (en) |
| TW (1) | TWI445618B (en) |
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| CN104247576B (en) * | 2012-04-24 | 2017-05-31 | 住友金属矿山株式会社 | 2 layers of flexible wiring substrate and flexible wiring and its manufacture method |
| CN110241389A (en) * | 2018-03-08 | 2019-09-17 | 日铁化学材料株式会社 | Deposition mask, deposition mask form the manufacturing method formed with polyamic acid, deposition mask with laminated body and deposition mask |
| CN112123196A (en) * | 2014-07-17 | 2020-12-25 | 应用材料公司 | Method and system for chemical mechanical polishing and polishing pad |
| CN112875639A (en) * | 2021-01-25 | 2021-06-01 | 上海交通大学 | Composite flexible substrate and manufacturing method thereof |
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| JP5918943B2 (en) * | 2011-08-10 | 2016-05-18 | 味の素株式会社 | Manufacturing method of semiconductor package |
| JP6090148B2 (en) * | 2013-12-19 | 2017-03-08 | 住友金属鉱山株式会社 | Method for determining adhesion strength of metal thin film / polyimide laminate, and metallized polyimide film substrate using the same |
| JP6361550B2 (en) * | 2015-03-30 | 2018-07-25 | 住友金属鉱山株式会社 | Method for judging quality of polyimide film, and method for producing copper-clad laminate and flexible wiring board using the polyimide film |
| KR20220093621A (en) | 2020-12-28 | 2022-07-05 | 주식회사 클랩 | Flexible copper foil film and manufactruing method thereof |
| KR20220093615A (en) | 2020-12-28 | 2022-07-05 | 주식회사 클랩 | Conductive metal layer, fine metal pattern, and manufacturing method thereof |
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- 2010-03-29 KR KR1020100027664A patent/KR101702128B1/en active IP Right Grant
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Also Published As
| Publication number | Publication date |
|---|---|
| TW201124266A (en) | 2011-07-16 |
| KR101702128B1 (en) | 2017-02-13 |
| KR20110083448A (en) | 2011-07-20 |
| TWI445618B (en) | 2014-07-21 |
| CN102131345B (en) | 2014-11-19 |
| JP5347980B2 (en) | 2013-11-20 |
| JP2011143595A (en) | 2011-07-28 |
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