CN107531921A

CN107531921A - Liquid crystal polymer films and circuit board

Info

Publication number: CN107531921A
Application number: CN201680024465.8A
Authority: CN
Inventors: 砂本辰也; 中岛崇裕; 高桥健; 小野寺稔
Original assignee: Kuraray Co Ltd
Current assignee: Kuraray Co Ltd
Priority date: 2015-04-27
Filing date: 2016-04-26
Publication date: 2018-01-02
Also published as: WO2016174868A1; JPWO2016174868A1; TWI760302B; TW201702067A; TW202126480A

Abstract

The present invention relates to a kind of liquid crystal polymer films, the toughness for utilizing film that the method using ASTM D882 as foundation measures, after the liquid crystal polymer films and conductor layer hot pressing are connected together is more than 30MPa below 100MPa.

Description

Liquid crystal polymer films and circuit board

Technical field

The present invention is that (below, have on a kind of liquid crystal polymer films for forming optical anisotropy melting behaviors When be referred to as liquid crystal polymer films or simply referred to as liquid crystal polymer film) and circuit board.

Background technology

In recent years, the communication equipment field such as the field of information processing such as PC, mobile phone has significant development, these Frequency forward direction gigahertz (GHZ) regional development used in electronics, communication equipment.However, in general well known is in this high frequency Transmission loss can become big in band, therefore require to reduce transmission loss.

More than conductor losses, dielectric loss are also relevant with the transmission loss of high-frequency signal.Then, believe to suppress high frequency Number transmission loss, lifting information processing rate be signal transmission speed, it is desirable to a kind of excellent electric insulation of dielectric property Property baseplate material.

From the point of view, using the dielectric loss liquid crystal polymer films smaller than Kapton as Insulative substrate, and utilize the mode circuit that the liquid crystal polymer film and conductor layer are fit together and formed of thermo-compression bonding Plate is just attracted attention.

As peel strength when determining liquid crystal polymer film and conductor layer being crimped together, (peel strength is glutinous Close intensity) height key element, it is contemplated that have：Anchoring effect caused by the surface roughness of conductor layer be mechanicalness combine, Combination with conductor layer surface treatment compounds and resin chemically combines.As improve conductor layer anchoring effect technology, Carry out improving anchoring effect by forming bumps in conductor layer, so that it is guaranteed that when conductor layer and insulating barrier are crimped together Peel strength processing, and studying the optimization of the concaveconvex shape.

For example, disclose a kind of metal-coating lamination in patent document 1 (International Publication WO2012/020818 pamphlets) Plate, its be on the single or double of liquid crystalline polymer layer have metal foil metal-coated laminated board, wherein metal foil and liquid The face of crystalline polymer layer contact has been carried out roughening treatment and has had thrust in skin section.Also disclose：By the height of thrust H is spent relative to the depth-width ratio (H/L) represented by the width L of the foundation part of thrust ratio in the range of 3~20, and is dashed forward The height of thing is played in the range of 0.1~2 μm, liquid crystalline polymer layer has 10~2000 μm of thickness, and film thickness tolerance is less than 6%.

Patent document 1：International Publication WO2012/020818 pamphlets

The content of the invention

The technical problems to be solved by the invention

If increasing the surface roughness of conductor layer to improve the anchoring effect of conductor layer, gather with thermoplastic liquid crystal High frequency characteristics of the insulation layer stackup such as compound film when getting up and forming circuit board will reduce, therefore from ensuring high frequency characteristics From the point of view of viewpoint, preferably using the low conductor layer of surface roughness.On the other hand, just using high frequency characteristics is excellent, table For the low conductor layer of surface roughness, peel strength when being gathered into folds with film layer is low, and the surface roughness of conductor layer is to high frequency Characteristic is opposite with being influenceed caused by peel strength.Then, it is desirable to a kind of liquid crystal polymer films, the thermoplasticity Liquid crystal polymer film also can in the case where the low conductor layer stackup of, surface roughness excellent with high frequency characteristics gets up Produce high-peeling strength.

The first object of the present invention is to provide a kind of liquid crystal polymer films, and the thermoplastic liquid crystal polymer is thin Film is in the case where conductor layer low with surface roughness etc. is connected together by adherend hot pressing, it may have produces high-peeling strength Specific toughness.

The second object of the present invention is to provide a kind of liquid crystal polymer films, and the thermoplastic liquid crystal polymer is thin Film is in the case where conductor layer low with surface roughness etc. is connected together by adherend hot pressing, it may have produces high-peeling strength , specific toughness and specific Young's modulus.

The third object of the present invention is to provide a kind of liquid crystal polymer films, and the thermoplastic liquid crystal polymer is thin Film toughness rate of descent after being connected together with conductor layer etc. by adherend hot pressing is also relatively low, can maintain specific toughness.

The fourth object of the present invention is to provide a kind of circuit board, and the circuit board is that the thermoplastic liquid crystal polymer is thin Film and conductor layer etc. are crimped together and are formed by adherends.

To solve the technical scheme of technical problem

The present inventors are concentrated on studies to achieve the above object, and result is to be found that following phenomenons, So as to complete the present invention.I.e.：As long as the toughness after being connected together with conductor layer hot pressing is fallen into the range of particular value Liquid crystal polymer films, then in the feelings being connected together with the conductor layer low such as surface roughness by adherend hot pressing Under condition, good high frequency characteristics also can be both maintained, realizes high-peeling strength again.

The present inventors also found following phenomenons, so as to complete the present invention.I.e.：As long as with specific The liquid crystal polymer films of toughness and specific Young's modulus, then in the quilt with the conductor layer low such as surface roughness In the case that adherend hot pressing is connected together, good high frequency characteristics also can be both maintained, realizes higher peel strength again.

The present inventors also found following phenomenons, so as to complete the present invention.I.e.：By using with specific The liquid crystal polymer films of toughness, and the liquid crystal polymer films toughness will not change must exceed spy Under conditions of determining scope, conductor layer etc. is connected together by adherend and the liquid crystal polymer films hot pressing, it becomes possible to High-peeling strength is also maintained after thermo-compression bonding.

I.e.：The first aspect of the present invention is related to a kind of liquid crystal polymer films, utilizes using ASTM D882 as foundation Method measure, the thermoplastic liquid crystal after liquid crystal polymer films are connected together with conductor layer hot pressing polymerize The toughness of thing film is more than 30MPa below 100MPa.

Can be such liquid crystal polymer films：Utilize what the method using ASTM D882 as foundation was measured Young's modulus is more than 2.0GPa below 4.0GPa.

It is also possible that liquid crystal polymer films：In -30 DEG C of the fusing point of liquid crystal polymer films After liquid crystal polymer films and conductor layer etc. are connected together by adherend hot pressing at following temperature, thermoplasticity liquid The toughness rate of descent of crystalline polymer film is within 30%.

In addition, the second aspect of the present invention be related to a kind of liquid crystal polymer films and conductor layer stackup get up and The circuit board of formation.

It can be such circuit board：Method of the utilization using ISO4287-1997 as foundation is measured, conductor layer surface 10 mean roughness (Rz_JIS) it is less than 3 μm.

It is also possible that circuit board：Method of the utilization using JIS C5016-1994 as foundation is measured, thermoplasticity Liquid crystal polymer film and the bonding strength between the conductor layer that sticks together of the liquid crystal polymer films are More than 0.6kN/m.

In addition, the third aspect of the present invention is related to a kind of circuit board, it includes liquid crystal polymer films and layer The conductor layer being stacked on liquid crystal polymer films, wherein：That method of the utilization using ASTM D882 as foundation is measured, Conductor layer is being stripped down to the toughness of the later liquid crystal polymer films from liquid crystal polymer films For more than 30MPa below 100MPa.

Invention effect

Because the liquid crystal polymer films of the present invention are with being able to maintain that good high frequency characteristics, rough surface Spend in the case that low conductor layer hot pressing is connected together, can also produce high-peeling strength, therefore both can maintain conductor layer Good high frequency characteristics be in high frequency band low transmission loss, and with high-peeling strength by liquid crystal polymer films with Conductor layer stackup gets up, and wherein the low conductor layer of the surface roughness is to utilize the method using ISO4287-1997 as foundation to measure , 10 mean roughness (Rz of conductor layer surface_JIS) it is less than 3 μm of conductor layers.

In addition, according to the liquid crystal polymer films of the present invention, thermoplastic liquid crystal can be gathered with high-peeling strength Compound film is with being able to maintain that good conductor layer stackup high frequency characteristics, that surface roughness is low.Therefore, will not be with Distance that liquid crystal polymer films are laminated between the concaveconvex shape for the conductor layer surface got up, bumps etc. is limited to specific shape In the case that shape, numerical value etc. just get up liquid crystal polymer films and conductor layer stackup, it can meet simultaneously good High frequency characteristics and high-peeling strength, so as to improve productivity, realize cost degradation.

Because the liquid crystal polymer films of the present invention can significantly reflect and liquid crystal polymer films Conductor layer of crimping etc. is by the anchoring effect of adherend, therefore in the conductor layer surface roughness that can maintain good high frequency characteristics That is, utilize 10 mean roughness (Rz of the conductor layer surface that method using ISO4287-1997 as foundation measures_JIS) it is 3 μm In following scope, the liquid crystal polymer films of anchoring effect high conductor layer and the present invention by surface roughness height Combine and be laminated, so as to produce higher peel strength.

In addition, the liquid crystal polymer films of the present invention its toughness rate of descent after thermo-compression bonding is relatively low, and And high-peeling strength can be also maintained after getting up with conductor layer stackup.

Brief description of the drawings

Fig. 1 is the schematic sectional view for illustrating the manufacturing process of the circuit board involved by one embodiment of the present invention, (a) state before stacking is shown, (b) shows the state after stacking.

Embodiment

[liquid crystal polymer films]

In the present invention, liquid crystal polymer films are as the unit electricity formed with conductor layer on single or double The insulating properties base material floor of road plate uses, but also (is sometimes referred to as below as to the circuit board material that is binded to conductor layer Make adhesion material) use.It should be noted that circuit board material can be selected from adhesive film (bonding sheet) and cover At least one of epiphragma (coverlay), preferably adhesive film.

Liquid crystal polymer films are formed by the liquid crystal polymer for being capable of melt-shaping.The thermoplastic liquid crystal gathers As long as compound is capable of the liquid crystal polymer of melt-shaping, its chemical component is not particularly limited, such as can be enumerated Go out：Thermoplastic liquid crystal polyester has imported thermoplastic liquid crystal polyesteramide of amido link etc. to it.

In addition, thermoplastic liquid crystal polymer can also be that aromatic polyester or aromatic polyester acid amides are further imported Imide bond, carbonic acid ester bond, carbodiimide key, isocyanurate-bond etc. are derived from the polymer that key of isocyanates etc. forms.

As the specific example of thermoplastic liquid crystal polymer used in the present invention, can include by being categorized into following institute Known thermoplastic liquid crystal polyester and thermoplastic liquid crystal polyester derived from (1) to the compound and its derivative of (4) illustrated Acid amides.However, can form the polymer of optically anisotropic melting behaviors to be formed, the combination of various starting compounds is worked as So there is appropriate scope.

(1) aromatic series or aliphatic dihydroxy compounds (typical example is with reference to table 1)

[table 1]

(2) aromatic series or aliphatic dicarboxylic acid (typical example is with reference to table 2)

[table 2]

(3) aromatic hydroxy-carboxylic (typical example is with reference to table 3)

[table 3]

(4) aromatic diamine, aromatic hydroxyl amine or aromatic amine yl carboxylic acid (typical example is with reference to table 4)

[table 4]

As the typical example of the liquid crystal polymer obtained by these starting compounds, can enumerate with shown in table 5 and table 6 Construction unit copolymer.

[table 5]

[table 6]

In these copolymers, preferably at least comprising P-hydroxybenzoic acid and/or 6-Hydroxy-2-naphthoic acid as weight The polymer of multiple unit, particularly preferably following (i), the polymer of (ii).(i) comprising P-hydroxybenzoic acid and 6- hydroxyls- The polymer of the repeat unit of 2- naphthoic acids.(ii) polymer of the repeat unit comprising following compositions：Selected from by para hydroxybenzene At least one of the group of formic acid and 6-Hydroxy-2-naphthoic acid composition aromatic hydroxy-carboxylic；Selected from by 4,4 '-dihydroxybiphenyl And at least one of group of quinhydrones composition aromatic diol；Selected from by terephthalic acid (TPA), M-phthalic acid and 2,6- naphthalene diformazan At least one of the group of acid composition aromatic dicarboxylic acid.

For example, for the polymer of (i), P-hydroxybenzoic acid and 6- hydroxyls are comprised at least in thermoplastic liquid crystal polymer In the case of the repeat unit of base -2- naphthoic acids, in liquid crystal polymer, as repeat unit (A) P-hydroxybenzoic acid with Mol ratio (A)/(B) as the 6-Hydroxy-2-naphthoic acid of repeat unit (B) is preferably that (A)/(B)=10/90~90/10 is left The right side, more preferably (A)/(B)=50/50~85/15 or so, more preferably (A)/(B)=60/40~80/20 or so.

In addition, for the polymer of (ii), in the group being made up of P-hydroxybenzoic acid and 6-Hydroxy-2-naphthoic acid At least one aromatic hydroxy-carboxylic (C)；Selected from least one of the group being made up of 4,4 '-dihydroxybiphenyl and quinhydrones virtue Fragrant race's glycol (D)；And selected from least one of group being made up of terephthalic acid (TPA), M-phthalic acid and NDA Aromatic dicarboxylic acid (E), each repeat unit in liquid crystal polymer mol ratio can be aromatic hydroxy-carboxylic (C): The aromatic diol (D):The aromatic dicarboxylic acid (E)=30~80:35~10:35~10 or so, it can be more preferably (C):(D):(E)=35~75:32.5~12.5:32.5~12.5 or so, can more preferably (C):(D):(E)=40 ~70:30~15:30~15 or so.

In addition, constitutional repeating unit of the constitutional repeating unit from aromatic dicarboxylic acid with being derived from aromatic diol rubs You are than being preferably (D)/(E)=95/100~100/95.If deviateing the scope, just occur that the degree of polymerization does not rise and mechanical strength The tendency of reduction.

It should be noted that the optically anisotropic melting behaviors (optical anisotropy during melting) referred in the present invention Such as can be assert by following manner, i.e.,：Sample is put on heating microscope carrier, in a nitrogen environment heating heating, seen Examine the transmitted light of sample.

It is preferably its fusing point (hereinafter referred to as Tm as thermoplastic liquid crystal polymer₀) in the range of 260~360 DEG C, more Preferably Tm₀In the range of 270~350 DEG C.It should be noted that Tm₀Can be by using differential scanning calorimeter (SHIMADZU CORPORATION DSC) is measured and tried to achieve to the temperature for main endothermic peak occur.

In the range of the effect of the present invention is not undermined, poly terephthalic acid can be added in thermoplastic liquid crystal polymer Glycol ester, modified polyethylene terephthalate, polyolefin, makrolon, polyarylate, polyamide, polyphenylene sulfide, polyethers The thermoplastic polymers such as ether ketone, fluororesin, various additives, filler can also be added according to demand.

Liquid crystal polymer films used in the present invention be to thermoplastic liquid crystal polymer carry out extrusion molding and Obtain.As long as the direction of the rigid rod-like molecules of thermoplastic liquid crystal polymer can be controlled, then arbitrary extruding can be used Forming process, but known T modulus methods, layered product pulling method, blowing (inflation) method etc. in industrial production advantageously.It is special It is not blow moulding, layered product pulling method, not only the machining direction (hereinafter referred to as MD directions) of film can be applied should Power, stress can also be applied to orthogonal direction (hereinafter referred to as TD directions), therefore can obtain controlling MD directions With the film of the dielectric property in TD directions.

In extrusion molding, in order to control orientation, preferably along with progress stretch processing, example while extruding Such as, in the extrusion molding carried out using T modulus methods, Ke Yishi：It is not only on the MD directions of film, but in MD directions and TD The molten mass sheet material squeezed out from T moulds is stretched simultaneously on the two directions of direction；Or first in the MD direction to from T The molten mass sheet material that mould squeezes out is stretched, and is then stretched on TD directions.

In addition, using blow moulding carry out extrusion molding in, can be with defined drawing ratio (equivalent to the stretching in MD directions Multiplying power) and blow-up ratio (equivalent to the stretching ratio in TD directions), to the cylindrical shape gone out from ring-like mould (ring die) melt extruded Sheet material is stretched.

For the stretching ratio of this extrusion molding, as the stretching ratio (or drawing ratio) on MD directions, such as can Think 1.0~10 or so, preferably 1.2~7 or so, more preferably 1.3~7 or so.In addition, as the stretching on TD directions times Rate (or blow-up ratio), such as can be 1.5~20 or so, preferably 2~15 or so, more preferably 2.5~14 or so.

MD directions for example can be less than 2.6 with the ratio between respective stretching ratio on TD directions (TD directions/MD directions), excellent Elect 0.4~2.5 or so as.

Furthermore, it is possible to liquid crystal polymer films are stretched as required after extrusion.Stretching side Method is known method in itself, can use any of biaxial stretch-formed, uniaxial tension, but from being more easily controlled molecularly oriented From the viewpoint of degree, preferably using biaxial stretch-formed.In addition, can be used known uniaxial tension machine, Dual-shaft synchronous stretching machine, by Secondary biaxial stretcher etc. is stretched.

Furthermore, it is possible to as required, known or usual heat treatment is carried out to adjust liquid crystal polymer films Fusing point and/or thermal coefficient of expansion.Heat treatment condition can be suitably set according to purpose, for example, can be by liquid crystal polymer Fusing point (Tm₀) more than -10 DEG C (such as Tm₀- 10~Tm₀+ 30 DEG C or so, preferably Tm₀~Tm₀+ 20 DEG C or so) at a temperature of A few houres are heated, so that the fusing point (Tm) of liquid crystal polymer films rises.

The liquid crystal polymer films of the invention obtained in this way have good dielectric property, agent of low hygroscopicity Deng, therefore it is suitable as circuit board material.

In addition, for liquid crystal polymer films, cause it in low sheraing region due to its rigid structure Melting viscosity typically can be higher, for example, the liquid crystal polymer films at 300 DEG C melting viscosity (shear rate 1, 000 second^-1) can be such as more than 100Pas, be preferably capable of for 200~100,000Pas or so (such as 150~ 100,000Pas or so), it more preferably can be 200~10,000Pas or so.It should be noted that melting viscosity Viscoelastic rheometer (such as TA Instrucment Japan AR2000) can be used, 3 DEG C/min of programming rate, Measured under conditions of frequency 1Hz, strain 0.1%, normal stress 5N.

From the purpose for the desired heat resistance and processability for obtaining film, the fusing point of liquid crystal polymer films (Tm) in the range of may be selected from 200~400 DEG C or so, preferably 250~360 DEG C or so, more preferably 260~340 DEG C or so. It should be noted that it can be observed by using thermal behavior of the differential scanning calorimeter to film and obtain the molten of film Point.As long as that is, the position of following endothermic peaks is recorded as to the fusing point of film, i.e.,:Speed with 20 DEG C/min makes After experiment is heated up with film and it is melted completely, fused mass is quenched to 50 DEG C with 50 DEG C/min of speed, then with 20 DEG C/ The endothermic peak occurred after the speed heating of minute.

Liquid crystal polymer films used in the present invention can be arbitrary thickness, wherein being also comprising thickness Below 5mm tabular or the liquid crystal polymer films of sheet.But, in the case of for high-frequency transmission line, heat The thickness of plasticity liquid crystal polymer film is thicker, and transmission loss preferably polymerize thermoplastic liquid crystal as far as possible with regard to smaller The thickness of thing film is thickening.In the case where using liquid crystal polymer films as electric insulation layer, the thickness of the film Preferably in the range of 10~500 μm, more preferably in the range of 15~200 μm.In the excessively thin situation of the thickness of film Under, the rigidity and intensity of film can diminish, therefore can also use and be laminated film of the film thickness in the range of 10~200 μm Get up to obtain the method for any thickness.

In this invention it is important that what is be connected together with conductor layer hot pressing is liquid crystal polymer films, sharp The toughness after being connected together with conductor layer hot pressing measured to the method that ASTM D882 are foundation is more than 30MPa Below 100MPa, it is preferably capable of as more than 35MPa below 100MPa, more preferably can is more than 50MPa 100MPa Below, it is further preferred that can be more than 60MPa below 100MPa, particularly preferably can be more than 70MPa 90MPa Below.The liquid crystal polymer films fallen into by using the toughness after being connected together with conductor layer hot pressing in the range of this, And peel strength when being got up with conductor layer etc. by adherend stacking can be improved, high stripping is also able to maintain that after thermo-compression bonding From intensity.

For the liquid crystal polymer films of the present invention, even in the film is superimposed together with copper foil, use Vacuum hot pressing device, crimping temperature (temperature of heating plate) is set in Tm-35 DEG C of the fusing point of the film, in 4MPa pressure Under, after having carried out the thermo-compression bonding of 10 minutes, the toughness of the film after copper foil is peeled off also can more than 30MPa 100MPa with Under.Particularly preferably following such liquid crystal polymer films, i.e.,：Even under the conditions of above-mentioned crimping, will press Jointing temp is set in any temperature in less than more than Tm-35 DEG C Tm-10 DEG C of scope under such circumstances, and toughness also can be More than 30MPa below 100MPa.

Further, since the higher film of toughness more can significantly reflect the anchoring effect of conductor layer and produce high stripping Intensity, therefore, it is possible to by by the high film of toughness and surface roughness it is big and the high conductor layer of anchoring effect combine into Row crimping, to obtain higher peel strength.

In general, the surface roughness of conductor layer is higher, anchoring effect just becomes higher, but transmission loss can be because table The bumps in face become the Kelvin effect caused by big this case and become big.Can be by the scope for not causing transmission loss to become big Interior (such as 10 mean roughness (Rz of the conductor layer surface measured using the method according to ISO4287-1997_JIS) it is 3 μm Conductor layer surface roughness is improved below), so as to both maintain good high frequency characteristics, realizes high-peeling strength again.It is small with regard to toughness For 30MPa liquid crystal polymer films, when with not causing to improve surface in the big scope of transmission loss change In the case that the conductor layer of roughness is crimped together, larger peel strength can not be obtained, due to being necessary to carry out special add Work, therefore manufacturing process is cumbersome, manufacturing condition is restricted, and the special processing is：Limit the concaveconvex shape of conductor layer surface, incite somebody to action Distance between bumps is limited in particular range etc..

For as resin film as liquid crystal polymer films and conductor layer by the layered product of adherend, By resin film and in the case of being peeled away by adherend, it is believed that the mode of stripping have interface peel and cohesional failure this Two ways.In the case where the peel strength of layered product reaches to a certain degree by force, the mode of stripping is mainly drawn by cohesional failure Hair.It is considered that：If the toughness of resin film during cohesional failure is stronger, resin film is difficult to be destroyed when peeling off, therefore Become strong by the peel strength of adherend and resin film.

The method for improving the toughness of liquid crystal polymer films is not particularly restricted, such as can pass through progress It is heat-treated to improve the toughness of film.For example, heat treatment temperature, heat treatment time, heating when can be heat-treated by controlling Speed etc. assigns the toughness of film to adjust, such as has following tendencies：If heat treatment is improved under the conditions of specific programming rate Temperature, then assigning the toughness of liquid crystal polymer films can improve, if in addition, growth heat treatment time, assigns thermoplastic The toughness of property liquid crystal polymer film can also improve.

This condition of heat treatment temperature is not particularly restricted, such as can be the molten of liquid crystal polymer films Point (Tm) more than -30 DEG C (such as Tm-20 DEG C~Tm+10 DEG C or so, preferably Tm~Tm+10 DEG C or so).

This condition of heat treatment time is not particularly restricted, such as can be 1 hour~20 hours or so (such as 5 Hour~15 hours or so, preferably 6 hours~10 hours or so).

From the viewpoint of the toughness for improving liquid crystal polymer films, this condition of programming rate is preferably for example 1 DEG C/min~6 DEG C/min, more preferably 1 DEG C/min~3 DEG C/min, if considering productivity, particularly preferably 2 DEG C/minute Clock.

For example, using single-screw extrusion machine, at 280~300 DEG C to by 27 moles of % of 6-Hydroxy-2-naphthoic acid unit, The thermotropic liquor polyester that 73 moles of % of P-hydroxybenzoic acid unit are formed carries out heating mixing, then utilizes diameter 40mm, slit Interval 0.6mm blow molding die (inflationdie) is extruded, so as to make the thermoplasticity liquid of 280 DEG C of fusing point, 50 μm of thickness Crystalline polymer film.By the way that in baking box in a nitrogen environment, programming rate 2 is carried out to the liquid crystal polymer films DEG C/min or so, 280 DEG C or so of heat treatment temperature, the heat treatment time heat treatment of 6 hours or so, just can obtain toughness is 80MPa or so liquid crystal polymer films；And 4 DEG C/min of programming rate is carried out to the liquid crystal polymer films Left and right, 280 DEG C or so of heat treatment temperature, the heat treatment time heat treatment of 5 hours or so, then it is left for 70MPa can to obtain toughness Right liquid crystal polymer films.

For example, the toughness of liquid crystal polymer films can be improved by heat treatment as described above etc., and By the way that the toughness of liquid crystal polymer films is set in higher value, then it is thermally compressed by the film and conductor layer After together, also the toughness of the liquid crystal polymer films can be made to maintain more than 30MPa below 100MPa, even if so as to Good peel strength is also able to maintain that after thermo-compression bonding has been carried out.

In order to further improve peel strength when liquid crystal polymer films and conductor layer hot pressing are connected together, The Young's modulus for the liquid crystal polymer films that the method using ASTM D882 specifications as foundation of utilization is measured is preferably More than 2.0GPa below 4.0GPa, more preferably more than 2.5GPa below 4GPa, more preferably more than 2.5GPa 3.5GPa Below.

The method for adjusting the Young's modulus of liquid crystal polymer films is not particularly restricted, such as can be passed through It is heat-treated to adjust Young's modulus.

For example, in the presence of if heat treatment temperature is improved, assigning the Young's modulus of liquid crystal polymer films will drop Low tendency.For example, using single-screw extrusion machine, at 280~300 DEG C to by 27 moles of % of 6-Hydroxy-2-naphthoic acid unit, The thermotropic liquor polyester that 73 moles of % of P-hydroxybenzoic acid unit are formed carries out heating mixing, then utilizes diameter 40mm, slit Interval 0.6mm blow molding die is extruded, and so as to make the liquid crystal polymer films of 280 DEG C of fusing point, 50 μm of thickness, is led to Cross in baking box in a nitrogen environment, the liquid crystal polymer films are carried out with 2 DEG C/min of programming rate or so, heat treatment 280 DEG C or so of temperature, the heat treatment time heat treatment of 6 hours or so, so as to obtain toughness as 80MPa or so, Young's modulus For 3.5GPa or so liquid crystal polymer films.

If additionally, there are reduce heat treatment temperature, the tendency that Young's modulus just improves, for example, being extruded using single screw rod Machine, to being made up of 73 moles of 27 moles of % of 6-Hydroxy-2-naphthoic acid unit, P-hydroxybenzoic acid unit % at 280~300 DEG C Thermotropic liquor polyester carry out heating mixing, then extruded using diameter 40mm, slit separation 0.6mm blow molding die, from And 280 DEG C of fusing point, the liquid crystal polymer films of 50 μm of thickness are made, when in baking box in a nitrogen environment, to the heat Plasticity liquid crystal polymer film has carried out 2 DEG C/min of programming rate or so, 260 DEG C or so of heat treatment temperature, heat treatment time 10 In the case of the heat treatment of or so hour, the thermoplasticity liquid that toughness is 80MPa or so, Young's modulus is 5.0GPa or so is obtained Crystalline polymer film.

Following tendencies be present：The temperature of the heat treatment carried out to liquid crystal polymer films is higher, the toughness of film Just become higher；Heat treatment time is longer, and the toughness of film just becomes higher.Therefore, thin to thermoplastic liquid crystal polymer When film assigns specific toughness, heat treatment temperature can be improved and shorten heat treatment time, heat treatment temperature can also be reduced And increase heat treatment time.The Young's modulus of liquid crystal polymer films has what is influenceed by such as heat treatment time Tendency, if sometimes heat treatment time is longer, Young's modulus just uprises, therefore can take into account liquid crystal polymer films Heat treatment temperature and heat treatment time are adjusted for balance between toughness and Young's modulus, so as to by toughness and Young mould Amount is set in particular range.Such as it can be fitted according to Young's modulus such heat treatment time condition in particular range is made Locality setting heat treatment temperature, so as to which liquid crystal polymer films are assigned with the toughness and Young's modulus of particular range.

In scope of the toughness in more than 30MPa below 100MPa of liquid crystal polymer films and thermoplastic liquid crystal In the case that the Young's modulus of thin polymer film is in more than 2.0GPa below 4.0GPa scope, the toughness that film be present is higher And Young's modulus is lower, the peel strength when being crimped together with conductor layer etc. by adherend just becomes higher tendency. From the viewpoint of further raising peel strength, film is adjusted when heat treatment via liquid crystal polymer films etc. Toughness and Young's modulus when, if by toughness improve and Young's modulus reduce in a manner of be adjusted if it is even more ideal.

[conductor layer]

Conductor layer is formed by least conductive metal, and known circuit fabrication side is utilized in the conductor layer Method is formed with circuit.As the method that conductor layer is formed in the insulating properties base material being made up of liquid crystal polymer films, Known method can be used, such as metal level can be deposited, metal level can also be formed via chemical plating, plating.This Outside, it can also utilize the mode of thermo-compression bonding that metal foil (such as copper foil) is crimped onto to the surface of liquid crystal polymer films On.

Form conductor layer metal foil be preferred for the metal foil of electrical connection, in addition to copper foil, additionally it is possible to include gold, The various metal foils such as silver, nickel, aluminium, the alloy that substantial (such as more than 98 mass %) are made up of these metals can also be included Paper tinsel.

In these metal foils, preferably using copper foil.As long as the copper foil that can be used in the circuit board, without special Limitation, can be any one of rolled copper foil, electrolytic copper foil.

In addition, conductor layer can also be in its surface formed with inoxidizability film.For example, in the case, element circuit The preparation process of plate can include：Metal foil is thermally compressed the hot pressing on the single or double of liquid crystal polymer films Connect step；And the inoxidizability film forming step of inoxidizability film is formed in the metal foil surface in thermo-compression bonding.

Silane coupler is set to be attached in conductor layer surface in addition, the preparation process of element circuit plate may further include Silane coupler attachment steps.

As inoxidizability film, can include for example：Inoxidizability alloy-layer, inoxidizability coating layer, BTA Antirust oxidant layer such as class etc..

It should be noted that can be according to conductor layer and the species of inoxidizability film, before circuit fabrication or circuit fabrication Inoxidizability film is formed afterwards.

For example, in the case where conductor layer includes the metal foil being thermally compressed, come from the viewpoint for for example improving adhesion See, as inoxidizability alloy-layer preferably with the alloy including at least the metal for forming metal foil.For example, led in composition In the case that the metal foil of body layer is copper foil, alloy-layer can be the alloy including at least copper.For example, it is preferable to in circuit fabrication Preceding formation inoxidizability alloy-layer.

For example, can be peddled with MEC Co., Ltd.s " FlatBOND GT " etc. form this alloy-layer.

It should be noted that there are following situations：The alloy component of not cupric in the part away from copper foil be present.In this feelings Under condition, etching solution can be utilized, the alloy component of not cupric is etched.As this etching solution, can include for example： " MEC REMOVER S-651A " (MEC Co., Ltd. system), " S-BACK H-150 " (SASAKI CHEMICAL CO., LTD. System), the aqueous solution comprising inorganic acids such as nitric acid etc..

In order to reduce due to the influence of Kelvin effect caused by the bumps of conductor layer, to maintain low transmission to be lost, preferably It is smaller for the surface roughness of conductor layer.It is averagely thick as 10 points measured by the method for foundation using ISO4287-1997 as utilizing Rugosity (Rz_JIS), the surface roughness of conductor layer is preferably capable of as less than 3 μm, more preferably can be less than 2.0 μm, It can be further preferably less than 1.5 μm.10 mean roughness (Rz_JIS) lower limit be not particularly restricted, such as It can be more than 0.1 μm, or more than 0.3 μm, can also be more than 0.5 μm.

In the present invention with said structure, when forming layered product, the face without the upper adhesive film of bonding of conductor layer Can also be smooth.It should be noted that though processing is formed with circuit in conductor layer, remaining conductor after circuit fabrication Surface can also be smooth.

The thickness of conductor layer is for example preferably in the range of 1~50 μm, more preferably in the range of 5~20 μm.

Furthermore from the viewpoint of the adhesion for improving conductor layer, known or usual silane coupler can also be made attached On conductor layer (particularly alloy-layer) surface.

[circuit board]

The circuit board that circuit board (being preferably multilayer circuit board) can be discussed further below, i.e.,：Possesses more than one unit Circuit board and it is a more than circuit board material, wherein the element circuit plate be by single or double formed with conductor layer What liquid crystal polymer films were formed, the circuit board material is by the heat for being binded with the conductor layer of the element circuit plate What plasticity liquid crystal polymer film was formed.Also, utilize using ISO4287-1997 as measured by the method for foundation and circuit board 10 mean roughness (Rz of the conductor layer surface of that side of material bonding_JIS) can be less than 3 μm.

For example, the circuit board of the present invention can be circuit board with following structure etc..

(i) possess element circuit plate and adhesive film, and more than two pieces of element circuit plate get up via adhesive film stacking and Into circuit board (multilayer circuit board), the wherein element circuit plate has the insulating barrier that is made up of liquid crystal polymer films (substrate layer) and form the conductor layer on the single or double of film；

(ii) possesses element circuit plate and for covering the circuit board of the cover layer of the conductor layer of the element circuit plate (individual layer or double-layer circuit board), wherein the element circuit plate have the insulating barrier (base being made up of liquid crystal polymer films Material layer) and form conductor layer on the single or double of film；

(iii) possess element circuit plate, adhesive film and cover layer, more than two pieces of element circuit plate is laminated via adhesive film Get up, and the outermost layer of circuit board is the circuit board (multilayer circuit being made up of the cover layer of the conductor layer of capping unit circuit board Plate), the circuit board has the structure that combination above-mentioned (i) and (ii) forms；

(iv) possesses the element circuit that polylith has the insulating barrier (substrate layer) being made up of liquid crystal polymer films Plate, and more than two pieces of element circuit plate is just directly laminated the circuit board (multilayer circuit board) of getting up not via adhesive film； And

(v) possess more than two pieces of element circuit plate and cover layer, more than two pieces of element circuit plate is not via bonding Piece just directly get up, and the outermost layer of circuit board is the circuit being made up of the cover layer of the conductor layer of capping unit circuit board by stacking Plate (multilayer circuit board), the circuit board have the structure that combination above-mentioned (ii) and (iv) forms.

Circuit board can be by the high-melting-point liquid crystal polymer film with high-fire resistance and with gathering than the high-melting-point liquid crystal The low-melting point liquid crystal thin polymer film of the low heat resistance of compound film is formed, for example, in insulated substrate, adhesive film and cover layer At least two circuit board materials can be by the high-melting-point liquid crystal polymer film with high-fire resistance and with than the high-melting-point liquid The low-melting point liquid crystal thin polymer film of the low heat resistance of crystalline polymer film is formed.In this case, high-melting-point liquid crystal polymer The fusing point difference of film and low-melting point liquid crystal thin polymer film is preferably 0~70 DEG C or so, more preferably 0~60 DEG C or so.

For example, showing layered product (circuit board) 30 in shown example in Fig. 1, the layered product 30 is via adhesive film Second unit circuit board 20 is layered in what is formed on first module circuit board 10 by 3, and wherein the first module circuit board 10 is to lead Body layer (copper foil) 4 is bonded on what insulating barrier formed on the two sides of liquid crystal polymer films 1, the second unit circuit board 20 be that conductor layer 4 is formed on the one side (upper surface) of the i.e. liquid crystal polymer films 2 of insulating barrier and formed, but is illustrated Structure be not intended to limit the present invention circuit board.For example, circuit board only can have two conductor layers, it is possible to have four Conductor layer more than individual.In addition, in order to cover conductor layer, circuit board can also possess by liquid crystal polymer film structure in outermost layer Into cover layer.

The circuit board of the present invention for example can be that the bonding strength between liquid crystal polymer film and conductor layer (is peeled off strong Degree) it is more than 0.6kN/m (such as 0.6~2kN/m), more preferably preferably more than 0.8kN/m, more than 1.0kN/m.Need Bright, the bonding strength (peel strength) can be following values：The method using JIS C5016-1994 as foundation is utilized, every Under minute 50mm speed, by the adhesion material being made up of liquid crystal polymer film towards relative to the liquid crystal polymer film Direction in 90 ° strips down with the layered product of conductor layer, while utilizes cupping machine [NIDEC-SHIMPO CORPORATION systems, DIGITAL FORCE GAUGEFGP-2] value of peel strength measured.

Because the circuit board of the present invention has used the good thermoplastic liquid crystal polymer of dielectric property as insulating materials, because This is be especially suitable for high-frequency circuit board.High-frequency circuit not only comprising the circuit for only transmitting high-frequency signal, also includes and is used for passing The circuit that the transmission path of the signal of defeated non-high-frequency signal is also located on same plane in the lump, wherein, for transmitting non-high frequency letter Number the transmission path of signal be, for example, following transmission paths etc., i.e.,：High-frequency signal is converted into low frequency signal, and by generation Low frequency signal transports to the transmission path of outside；For supplying the transmission path of power supply, the power supply is supplied to drive high-frequency unit.

For example, under 10GHz frequency, the relative dielectric constant (ε of circuit board_r) for example can be 2.6~3.5, it is more excellent Choosing be can be 2.6~3.4.

In addition, for example under 10GHz frequency, the dielectric loss angle tangent (Tan δ) of circuit board for example can be 0.001 More preferably can be 0.001 to 0.008 to 0.01.

[manufacture method of circuit board]

Hereinafter, the manufacture method of the circuit board of the present invention is illustrated.

(preparatory unit circuit board)

First, more than one element circuit plate is prepared, the element circuit plate has by liquid crystal polymer films structure Into insulating properties base material layer and form conductor layer on the single or double of the substrate layer.Liquid crystal polymer films Liquid crystal polymer films and conductor layer with above-mentioned illustrated structure can be used with conductor layer.

(preparing the circuit board material for being binded with conductor layer)

, can be with addition to said units circuit board as the circuit board material (adhesion material) for being binded with conductor layer Prepare to be used for the circuit board material binded with the conductor layer of element circuit plate more than a in addition.As long as adhesion material thermoplastic Property liquid crystal polymer film, for example, can specifically include selected from least one of adhesive film and cover layer.

It should be noted that as adhesion materials'use liquid crystal polymer film can use it is above-mentioned described in heat Plasticity liquid crystal polymer film.According to the structure of circuit board, the fusing point as the liquid crystal polymer film of adhesion materials'use Can be identical with the fusing point of the base material of element circuit plate, but be preferably using liquid crystal polymer of the fusing point than forming element circuit plate The low liquid crystal polymer film of film.In the case, both fusing point differences for example can be 0~70 DEG C or so, more preferably 0 ~60 DEG C or so.

(thermo-compression bonding step)

The method that liquid crystal polymer films are connected together with conductor layer hot pressing is not particularly restricted, such as Batch (batch) formula vacuum hot-pressing, roll-in method, double belt pressing (double belt press) etc. can be used.Roll-in Method, double belt pressing can also be roll-in method, the double belt pressings carried out in a manner of roll-to-roll (Roll to Roll).

Liquid crystal polymer films and conductor layer (such as metal foil) are being laminated using batch vacuum hot-pressing In the case of getting up, such as vacuum hot pressing device can be used, the liquid crystal polymer films of prescribed level will be cut into Between two pieces of heating plates of the vacuum hot pressing device being placed on metal foil overlapping, and be thermally compressed under vacuum conditions (batch Secondary formula vacuum hotpressing layered manner).

Formed liquid crystal polymer films are got up with conductor layer (such as metal foil) stacking using roll-in method Layered product, in the case of producing one side metal-coated laminated board, can be it is such, i.e.,：Carry thermoplastic liquid crystal polymerization Thing film is allowed to advance with metal foil, and they are overlapped while introducing warmed-up metallic roll and being connect with the metallic roll Between tactile rubber rollers, make them by being connected together between roller and hot pressing, so as to form layered product, thus make metal foil It is bonded on the one side metal-coated laminated board formed on the one side of film.At this point it is possible to there is preheating step, in the preheating step In, before by between roller, make film into registration rubber rollers, metal foil is merged with the film stack and be bonded on one temporarily Rise, preheating step can be following such preheating steps, i.e.,：With the angle that film contacts with rubber rollers relative to rubber rollers with The mode that this benchmark of the point of contact of metallic roll is fallen into the range of 90~120 ° introduces film.

Using roll-in method by conductor layer (such as metal foil) be layered on the two sides of liquid crystal polymer films come Formed layered product, in the case of producing two-sided metal-coated laminated board, can by crimped between heating roller come Manufacture metal foil is bonded on the two-sided metal-coated laminated board formed on the two sides of liquid crystal polymer films.At this point it is possible to Manufactured using the manufacture method of two-sided metal-coated laminated board, the method is characterized in that carrying out following three steps.(1) First step：Two panels metal foil is preheated respectively before two panels metal foil contacts with heating roller.(2) second step：Through The metal foil that the two panels crossed after first step is preheated to 100~250 DEG C of temperature connects with a pair of corresponding heating rollers respectively Touch, and be by relative to this benchmark of the point of contact of a pair of heating rollers into 70~200 ° of angle, θ in a manner of contact, metal foil While transported on heating roller, one side thermal expansion and turn into non-tension.(3) third step：By carrying out second step And as non-tension and the two panels metal foil transported respectively on a pair of corresponding heating rollers and in two panels gold The liquid crystal polymer films being transported between category paper tinsel are crimped and are integrally formed between heating roller, thus resulting Laminate is just transported between heating roller.

Liquid crystal polymer films and conductor layer (such as metal foil) stacking are being got up using double belt pressing And in the case of forming layered product, Ke Yishi：First, liquid crystal polymer films and metal foil are overlapped, then, double In belt press, at a temperature of between the fusing point of liquid crystal polymer films and the deterioration point of film, apply about 5 ~500 bars of pressure presses metal foil and the film, them is bonded together and forms layered product.Now, the pressure of pressing Power can also be about 5~100 bars, alternatively, it is also possible to when making that film is in the delay of the temperature higher than its fusing point in pressing Between be 0.5~1000 second, in addition, temperature can also be can obtain peel strength be per straight line 1cm more than 10N and size it is steady Qualitatively thermoplastic liquid crystal polymer/metal foil layer laminate as temperature of the change less than ± 0.2%.

Hot pressing jointing temp when liquid crystal polymer films and conductor layer hot pressing are connected together is preferably film Tm-30 DEG C of fusing point below, more preferably can be less than Tm-35 DEG C, it is further preferred that can for Tm-40 DEG C with Under.By being thermally compressed in this temperature range, and the thermoplastic liquid crystal polymer that can further suppress after thermo-compression bonding is thin The toughness rate of descent of film.

Under the toughness of liquid crystal polymer film after liquid crystal polymer films and conductor layer hot pressing are connected together Drop rate is preferably within 30%, within more preferably 25%, within more preferably 15%, still more preferably for 5% with It is interior.When the toughness rate of descent of the liquid crystal polymer film after thermo-compression bonding is fallen into the range of this, also it is able to maintain that after thermo-compression bonding Higher peel strength.

As long as in addition, what is be connected together with conductor layer hot pressing is liquid crystal polymer films, hot with conductor layer Toughness after being crimped together is more than 30MPa below 100MPa, then can be according to the property of liquid crystal polymer films The pressure applied when selecting thermo-compression bonding in the scope so wide from such as 0.5~6MPa.For example, even if press pressure be 5MPa with Under, especially for below 4.5MPa (such as 0.5MPa~3MPa, preferably 1~2.5MPa), it can also realize liquid crystal polymer The good bonding of film and conductor interlayer.

The present invention circuit board in, according to JIS C5016-1994 measure, liquid crystal polymer films with Bonding strength (peel strength) between conductor layer is preferably more than 0.6kN/m, more preferably more than 0.8kN/m, further excellent Elect more than 1.0kN/m as.

It should be noted that in the range of the effect of the present invention is not undermined, circuit board material can be carried out at surface Reason.The known methods such as surface treatment can irradiate for example, by ultraviolet, plasma irradiating, physical grinding are carried out.

Embodiment

Hereinafter, the present invention is illustrated in further detail using embodiment, but the present invention is not by any limit of the present embodiment System.It should be noted that in following examples and comparative example, various physical property are measured using following methods.

(toughness (MPa))

The toughness (MPa) of liquid crystal polymer films is according to the method measurement utilized using ASTM D882 as foundation The elongation and the measured value of the maximum tensile strength gone out, calculated and obtained using following formula (1).

Toughness=elongation × the maximum tensile strength × 1/2 (1)

In addition, the toughness (MPa) of the liquid crystal polymer films after thermo-compression bonding, is by thermoplastic liquid crystal polymer After film is connected together with conductor layer hot pressing, liquid crystal polymer films are stripped down from conductor layer, and using together What the method for sample was obtained.

(the toughness rate of descent (%) after thermo-compression bonding)

Respectively measurement thermo-compression bonding before liquid crystal polymer films toughness (MPa) and with by adherend hot pressing The toughness (MPa) of the film after being connected together, the front and rear toughness rate of descent of thermo-compression bonding is obtained.

Toughness rate of descent (%)=100 × (toughness (MPa) after toughness (MPa)-thermo-compression bonding before thermo-compression bonding)/thermo-compression bonding Preceding toughness (MPa)

(Young's modulus (GPa))

The Young's modulus (GPa) of liquid crystal polymer films is to utilize the method using ASTM D882 as foundation, is passed through Tensile load is applied to film and obtains its displacement, so as to be calculated and obtained using following formula (2).

E=(σ_n+1-σ_n)/(ε_n+1-ε_n) (2)

(here, E：Young's modulus (GPa)；σ_n+1-σ_n：The variable quantity of tensile stress when changing tensile load；ε_n+1- ε_n：The variable quantity of elongation strain when changing tensile load)

(surface roughness (Rz_JIS)(μm))

Using contact surface roughometer (Mitutoyo Corporation systems, model SJ-201), measure in layer 10 mean roughness (Rz of the copper foil surface of roughening treatment have been carried out in laminate_JIS).Measurement is utilized with ISO4287-1997 For foundation method carry out.More specifically, surface roughness (Rz_JIS) be:Its average line direction is pressed from roughness curve Sample one section of datum length, the absolute altitude of the highest summit (summit of convex curve) of the sampling part to the 5th summit Average value and minimum the lowest point (to the bottom point of recessed curve) being averaged to the absolute altitude of the 5th the lowest point of the sampling part The difference of value, the difference is μm to represent.Surface roughness (Rz_JIS) show 10 mean roughness.

(bonding strength：Peel strength (kN/m))

The method using JIS C5016-1994 as foundation is utilized, will be by liquid crystal polymer under 50mm per minute speed Under the adhesion material that film is formed is peeled off towards the direction in 90 ° of the layered product relative to liquid crystal polymer film and conductor layer Come, while surveyed using cupping machine [NIDEC-SHIMPO CORPORATION systems, DIGITAL FORCE GAUGE FGP-2] Peel strength is measured, using resulting value as bonding strength (peel strength) (kN/m).

(measurement of transmission loss (db/cm))

Use microwave network analyzer [Agilent company systems, model：8722ES] and probe (Cascade Microtech, Inc. system, model：ACP40-250), measurement frequency 10GHz S21 parameters are measured with microstrip line construction.

[embodiment 1]

335 DEG C of fusing point, toughness 80MPa, Young's modulus 3.5GPa liquid crystal polymer films are prepared.As leading Body layer is by surface roughness Rz_JISFor 2.5 μm of rolled copper foils (Mitsui Mining＆Smelting Co., Ltd.s system, SQ- VLP, 12 μm of thickness) it is folded on the liquid crystal polymer films, and vacuum hot pressing device is used, heating plate is set as 300 DEG C (Tm-35 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, carry out 10 minutes thermo-compression bonding and Layered product is produced.

For produced layered product, measure copper foil and liquid crystal polymer films peel strength and The toughness of liquid crystal polymer films after thermo-compression bonding.The toughness of liquid crystal polymer films after thermo-compression bonding is not Decline.Show the result in table 7.

[embodiment 2]

325 DEG C of fusing point, toughness 68MPa, Young's modulus 3.0GPa liquid crystal polymer films are prepared.As leading Body layer is by surface roughness Rz_JISFor 2.5 μm of rolled copper foils (Mitsui Mining＆Smelting Co., Ltd.s system, SQ- VLP, 12 μm of thickness) it is folded on the liquid crystal polymer films, and vacuum hot pressing device is used, heating plate is set as 295 DEG C (Tm-30 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, carry out 10 minutes thermo-compression bonding and Layered product is produced.

For produced layered product, measure copper foil and liquid crystal polymer films peel strength and The toughness of liquid crystal polymer films after thermo-compression bonding.The toughness of liquid crystal polymer films after thermo-compression bonding declines Rate is 19%.Show the result in table 7.

[embodiment 3]

280 DEG C of fusing point, toughness 42MPa, Young's modulus 2.5GPa liquid crystal polymer films are prepared.As leading Body layer is by surface roughness Rz_JISFor 2.5 μm of rolled copper foils (Mitsui Mining＆Smelting Co., Ltd.s system, SQ- VLP, 12 μm of thickness) it is folded on the liquid crystal polymer films, and vacuum hot pressing device is used, heating plate is set as 250 DEG C (Tm-30 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, carry out 10 minutes thermo-compression bonding and Layered product is produced.

For produced layered product, measure copper foil and liquid crystal polymer films peel strength and The toughness of liquid crystal polymer films after thermo-compression bonding.The toughness of liquid crystal polymer films after thermo-compression bonding declines Rate is 17%.Show the result in table 7.

[embodiment 4]

335 DEG C of fusing point, toughness 80MPa, Young's modulus 3.5GPa liquid crystal polymer films are prepared.As leading Body layer is by surface roughness Rz_JISFor 1.0 μm of rolled copper foils (JX Nippon Mining＆Metals Corporation systems, BHY-X, 12 μm of thickness) it is folded on the liquid crystal polymer films, and vacuum hot pressing device is used, heating plate is set For 300 DEG C (Tm-35 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, the thermo-compression bonding of 10 minutes is carried out And layered product is produced.

[embodiment 5]

335 DEG C of fusing point, toughness 80MPa, Young's modulus 3.5GPa liquid crystal polymer films are prepared.As leading Body layer is by surface roughness Rz_JISFor 1.0 μm of rolled copper foils (JX Nippon Mining＆Metals Corporation systems, BHY-X, 12 μm of thickness) it is folded on the liquid crystal polymer films, and vacuum hot pressing device is used, heating plate is set For 325 DEG C (Tm-10 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, the thermo-compression bonding of 10 minutes is carried out And layered product is produced.

For produced layered product, measure copper foil and liquid crystal polymer films peel strength and The toughness of liquid crystal polymer films after thermo-compression bonding.The toughness of liquid crystal polymer films after thermo-compression bonding declines Rate is 37.5%.Show the result in table 7.

[comparative example 1]

320 DEG C of fusing point, toughness 16MPa, Young's modulus 4.0GPa liquid crystal polymer films are prepared.As leading Body layer is by surface roughness Rz_JISFor 2.5 μm of rolled copper foils (Mitsui Mining＆Smelting Co., Ltd.s system, SQ- VLP, 12 μm of thickness) it is folded on the liquid crystal polymer films, and vacuum hot pressing device is used, heating plate is set as 290 DEG C (Tm-30 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, carry out 10 minutes thermo-compression bonding and Layered product is produced.

[comparative example 2]

Using single-screw extrusion machine, at 280~300 DEG C to by 27 moles of % of 6-Hydroxy-2-naphthoic acid unit, to hydroxyl The thermotropic liquor polyester that 73 moles of % of benzoic acid unit are formed carries out heating mixing, then utilizes diameter 40mm, slit separation 0.6mm blow molding die is extruded, so as to obtain the film of 50 μm of thickness.The fusing point Tm of the film is 280 DEG C, and toughness is 20MPa。

As conductor layer by surface roughness Rz_JISFor 2.5 μm of rolled copper foils (Mitsui Mining＆Smelting Co., Ltd.'s system, SQ-VLP, 12 μm of thickness) it is folded on the liquid crystal polymer films, and vacuum hot pressing device is used, Heating plate is set as 250 DEG C (Tm-30 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, carries out 10 Minute thermo-compression bonding and produced layered product.

[comparative example 3]

Using single-screw extrusion machine, at 280~300 DEG C to by 27 moles of % of 6-Hydroxy-2-naphthoic acid unit, to hydroxyl The thermotropic liquor polyester that 73 moles of % of benzoic acid unit are formed carries out heating mixing, then utilizes diameter 40mm, slit separation 0.6mm blow molding die is extruded, so as to obtain the film of 50 μm of thickness.The fusing point Tm of the film is 280 DEG C.

Resulting film is heat-treated.In heat treatment, without the heating of temperature, but by film surface Temperature is fixed on 260 DEG C to carry out the heat treatment of 4 hours, and film surface temperature then is fixed on into 285 DEG C to carry out 6 hours Heat treatment, so as to be heat-treated with two stage temperature conditionss.The fusing point of resulting liquid crystal polymer films Tm is 350 DEG C, toughness 20MPa.

As conductor layer by surface roughness Rz_JISFor 1.0 μm of rolled copper foils (JX Nippon Mining＆Metals Corporation systems, BHY-X, 12 μm of thickness) it is folded on the liquid crystal polymer films, and be pressed using Vacuum Heat Put, heating plate is set as 300 DEG C (Tm-50 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, carry out The thermo-compression bonding of 10 minutes and produced layered product.

[comparative example 4]

Resulting film is heat-treated.In heat treatment, without the heating of temperature, but by film surface Temperature is fixed on 260 DEG C to carry out the heat treatment of 4 hours, and film surface temperature then is fixed on into 300 DEG C to carry out 6 hours Heat treatment, so as to be heat-treated with two stage temperature conditionss.The fusing point of resulting liquid crystal polymer films Tm is 335 DEG C, toughness 18MPa.

As conductor layer by surface roughness Rz_JISFor 1.0 μm of rolled copper foils (JX Nippon Mining＆Metals Corporation systems, BHY-X, 12 μm of thickness) it is folded on the liquid crystal polymer films, and be pressed using Vacuum Heat Put, heating plate is set as 305 DEG C (Tm-30 DEG C of fusing points of liquid crystal polymer films), under 4MPa pressure, carry out The thermo-compression bonding of 10 minutes and produced layered product.

[table 7]

It was found from the result of embodiment 1~3：The toughness of liquid crystal polymer films after thermo-compression bonding is higher, copper foil It is bigger with the peel strength of liquid crystal polymer films.

Moreover, understand：The toughness of the liquid crystal polymer films of comparative example 1~4 is less than 30MPa, as comparative example 1~ The peel strength of the relatively low film of 4 such toughness and copper foil is below 0.6kN/m, and shown is relatively low value.

To embodiment 4 compared with embodiment 5, it is known that：Due to being thin in thermoplastic liquid crystal polymer in example 4 Liquid crystal polymer films and copper foil are crimped together at a temperature of -35 DEG C of the fusing point (Tm) of film, therefore are thermally compressed The toughness of film afterwards is 80MPa, and the toughness after thermo-compression bonding does not decline, thus can produce as 1.2kN/m it is high peel off it is strong Degree.On the other hand, due to being by liquid crystal polymer films and copper foil pressure in embodiment 5 at a temperature of Tm-10 DEG C It is connected together, therefore the toughness of the film after thermo-compression bonding is 50MPa, its rate of descent is up to 37.5%, and result is peel strength For 0.8kN/m.The embodiment 4 that toughness rate of descent after thermo-compression bonding suppresses relatively low good result has been obtained into.

In addition, as shown in table 7, embodiment 1~5 can obtain the transmission loss equal with comparative example 1~4, can more than Know, embodiment 1~5 can both maintain good high frequency characteristics, realize high-peeling strength again.

Symbol description

1 liquid crystal polymer films

2 liquid crystal polymer films

3 adhesive films

4 conductor layers (copper foil)

10 first module circuit boards

20 second unit circuit boards

30 layered products (circuit board)

Claims

A kind of 1. liquid crystal polymer films, it is characterised in that：

It is that the method using ASTM D882 as foundation of utilization is measured, the liquid crystal polymer films and conductor layer are warm The toughness of the liquid crystal polymer films after being crimped together is more than 30MPa below 100MPa.
2. liquid crystal polymer films according to claim 1, it is characterised in that：

The Young's modulus for the liquid crystal polymer films that the method using ASTM D882 as foundation of utilization is measured is More than 2.0GPa below 4.0GPa.
3. liquid crystal polymer films according to claim 1 or 2, it is characterised in that：

At temperature below Tm-30 DEG C of the fusing point of the liquid crystal polymer films, by the thermoplastic liquid crystal polymer Film and the conductor layer hot pressing be connected together after, the toughness rates of descent of the liquid crystal polymer films for 30% with It is interior.
A kind of 4. circuit board, it is characterised in that：

The circuit board is by the liquid crystal polymer films any one of claims 1 to 3 and conductor layer stackup Get up.
5. circuit board according to claim 4, it is characterised in that：

10 mean roughness on the surface for the conductor layer that method of the utilization using ISO4287-1997 as foundation is measured Rz_JISFor less than 3 μm.
6. the circuit board according to claim 4 or 5, it is characterised in that：

Liquid crystal polymer films that method of the utilization using JIS C5016-1994 as foundation is measured, described and and the heat Bonding strength between the conductor layer that plasticity liquid crystal polymer film sticks together is more than 0.6kN/m.
7. a kind of circuit board, it includes liquid crystal polymer films and is layered in the liquid crystal polymer films On conductor layer, it is characterised in that：

It is that method of the utilization using ASTM D882 as foundation is measured, the conductor layer is thin from the thermoplastic liquid crystal polymer The toughness of the liquid crystal polymer films after being stripped down on film is more than 30MPa below 100MPa.