CN1004987B - Process for producing coating copper-laminated for printed circuit boards - Google Patents

Abstract

A Cu-coated substrate for printed circuits is made by impregnating a glass fibre fabric with an accelerated resin system and pre- hardening, pre-heating to reduce the viscosity of the resin system, feeding into the pressure zone of a double-band press, pressing together with a Cu foil at increased temp. and cutting the substrate strip to required length. Pref. pressing is at an increasing temp. from 150-210 deg.C, and 25-80 bars. The substrate obtd. may be cooled under pressure, pref. in a cooling zone within the press and may be post-tempered. A release film may be applied to the side away from the Cu film, and be removed after leaving the press. The process is continuous and gives substrates of uniform, high quality.

Description

Make the production method of covering metal laminate of use in printed circuit board

The invention relates to according to preamble in the claim 1 describedly, produce the process of covering metal laminate as printed circuit board (PCB).

The metal laminate that covers that is used for printed circuit board (PCB) generally uses discontinuous method manufacturing.During manufacturing, the laminated material that is impregnated with thermosetting resin that is cut into certain size is suppressed on multidaylight press with metal forming.This manufacture method is the cost height not only, and every of being produced covers metal laminate, and quality is uneven.Therefore, wish to use certain continuous producing method for a long time always.

At UK Patent Application № .2, in 108,427, a kind of method is disclosed, this method is produced to step towards serialization and is gone a step further.The method of putting down in writing in this article adopts the press that two blocks of heated plates are housed intermittently to suppress, and its mode of operation is: the piece of cloth and the Copper Foil that are admitted in this press are all fixing during pressurized operation, regularly send the compacted products that makes.Therefore, the product that this method is made is sectional, and its size is subjected to the heating plate size and limits, and is connected to each other together by uninflated part, that is to say by out of use part to be connected to each other together.Even so, the quality of different parts is also inequality on a plate, therefore when the user needs the uniform product of quality, must cause scrapping in a large number of product.

As the purpose on basis of the present invention, be to propose the continuous processing method of covering metal laminate of a kind of production as use in printed circuit board.

This goal of the invention that is proposed is that those technical characterictics by characteristic in the claim 1 reach.

Heating in advance scribbles the method for operating of the laminated material plate of aathermoset resin system under pressurized conditions not, make and adopt suitable double belt press to become possibility, thereby continuously the quality of production good cover metal laminate.This fact is all beyond one's expectations, especially more unexpected when expecting following phenomenon, promptly the resin (that is to say finish react resin) after the sclerosis is an inertia, and can not have bonding force again, coagulated and prevulcanized resin system is because the result that the laminated material plate is preheated by short in addition, its sclerous reaction is further quickened.If according to the top viewpoint of mentioning in that part UK Patent Application, the unexpected sympathetic meeting utmost point of the sort of height of brainstrust impression occurs significantly so.Because for fear of do not wish the reaction in advance that occurs, suggestion that is to say and preserves this resin total overall reaction activity, so that producing adhesive effect during the pressing operation between each layer at this resin of cooling after the resin-coating and before the pressurized operation in that part application.If think, normally harden, that is to say at coagulating and the method for this recommendation that proposes of pre-hardening resin not at certain without short, it is measure of the present invention, it is the measure of a kind of like this resin of preheating, this resin is because pre-hardening has lost the partial reaction activity, and the blood coagulation enhancing effect between the period of heating makes its reactivity disappear with faster rate, and so this viewpoint is seemingly very absurd.Yet, though the direct contradiction of being recommended in this preheating measure and the prior art in fact but makes the metal laminate that covers of continuous production printed circuit board (PCB) become possibility.Obviously, this is coagulated and prevulcanized resin produces pre-reaction by short owing to preheating, and the result of this pre-reaction makes this resin in adding to depress in the reaction and be activated subsequently, so that this resin itself produces instantaneous bonding force in press.

Owing to adopt the result of the inventive method, viewed shortcoming in the hit and miss method of top introduction or batch process, promptly concerning every block of plate, its marginal zone quality is low, middle part quality height, the shortcoming that exists difference in quality on this different parts is eliminated, therefore make make to cover the metal laminate quality high and evenly, and can be cut into certain length, make the uniform plate of quality.

The mode of operation of double belt press is for example disclosed with in the plywood production at decoration.But in production method of the present invention, the temperature and pressure that uses for the double belt press has stricter requirement.For the stable and consistent of product surface quality of sending by press and size, stricter requirement is arranged also.For the type of the double belt press that is suitable for using,, once did introduction in 026,396 and 0,026,401 for example at european patent application № .0.

Preferably each layer scribbled the laminated material of thermosetting resin system, be delivered to together before the preheating zone of double belt press.This resin system is generally the B-state here by pre-hardening.The target here preferably reaches more senior B-state, that is to say with pre-hardening in the multilayer pressing during to compare resin flow littler.The structure of this multilayer preheating zone before being in pressor areas is in the ordinary course of things heated equably.Because in the resin deliquescing with when becoming plasticity, its viscosity reduction is so any uneven part that may exist is able to leveling in this stage.Used preheat temperature depends on the system of resin, and the temperature of preferentially selecting for use is 80～100 ℃.Sandwich construction feeds pressor areas from the preheating zone under about 100 ℃ of temperature, preferably a slice or two metal formings of preheating combine separately at once with in advance to make its one or both sides, and preferably under the condition that temperature increases progressively, under for example 150 °～210 ℃ the condition, compacting, pressure for example are 25 to 80 crust.Cooling this moment cover metal laminate by what several layer materials constituted then, be preferably in cooling pressure under, it is to cool off under the condition that keeps press power, and its temperature is reduced to below the glass state temperature of this resin to well.In case of necessity, it is done further heat treatment, be cut into required size then.Depress cooling adding, that is to say in press and cool off that purpose is to guarantee that the metal laminate that covers with this continuation method makes has very high quality, specifically to prevent its distortion.

Some can be used as the resin of rapid hardening aathermoset resin system, as epoxy resin, polyester and phenolic resins.

Using epoxy resin hardener-catalyst system, is favourable as the rapid hardening aathermoset resin system.And in the pyridine based compound, following pyridine compounds is the coagulant that is suitable for:

The 2-benzoylpyridine

The 3-benzoylpyridine

The 4-benzoylpyridine

2-benzyl pyridine

3-benzyl pyridine

4-benzyl pyridine

2-benzyl aminopyridine

4-dimethylaminopyridine

The 2-methoxypyridine

The 4-tert .-butylpyridine

The 3-cyanopyridine

2 hydroxy pyrimidine

6-amino-2-pyridine

The 2-aminopyridine

3-ethylpyridine

3-ethyl-4-picoline

The 2-phenylpyridine

2, the 6-diamino-pyridine

The 3-picoline

The 2-(amino methyl)-pyridine

2-amino-4-picoline

2, the 4-lutidines

Operable second group of coagulant is the imidazolium compounds class of itself known replacement, comprising imidazoles itself, specifically includes:

The N-methylimidazole

Glyoxal ethyline

The 2-phenylimidazole

The 4-phenylimidazole

4-methylimidazole

The 2-tolimidazole

5, the 6-dimethylbenzimidazole

1-methyl-2-Phenylbenzimidazole

1, the 2-methylimidazole

4, the 5-diphenyl-imidazole

2-ethyl-4-methylimidazole

The phosphinylidyne diimidazole

Imidazoles

The 2-undecyl imidazole

1-cyanoethyl-2-phenylimidazole

2-Phenylbenzimidazole

By application make dicyano diamides or benzyl dimethyl amine with above the method that combines of the pyridines mentioned or glyoxaline compound, obtained extraordinary result.Simultaneously, catalogue of the present invention be to obtain than known resin system higher blood coagulation enhancing effect is arranged, especially on this press, obtain economically reasonably through flow velocity.

Considerable other principal advantages of the inventive method is as follows:

-because the semi-finished product stock of producing is a continuous slab, can be cut into required size, so can utilize prepared sheet material semi-finished product fullest;

-owing to only need to repair the both sides of the plate of producing, so the energy economical with materials;

-owing to the energy consumption in the multidaylight press method of having avoided cooling down operation and therefore having caused, so the energy conserve energy;

-improved the quality of laminated plate, especially guaranteed the constant unanimity of its size;

-owing to copper foil surface more cleans, so reduced percent defective.

Compare with the sort of intermittent type production method in the so-called multidaylight press method, the present invention can reduce a large amount of process operation programs, and the specific operation process that can save has; With prepreg be cut into regulation length, with metal forming be cut into the length of regulation, in advance carry the semi-solid preparation straight sheet pile, lamination straight sheet pile Cheng Duo, with the lamination straight sheet pile separately, can save expensive increased pressure board, and only avoid using can be with once backing paper etc.

Referring now to the suitable concrete facilities and equipments (for the explanation of accompanying drawing ills) of implementing the inventive method, the present invention done illustrating in greater detail.

Equipment shown in the figure is double belt press 1, and it has a pressor areas 2 and a nothing that is in pressor areas the place ahead to press preheating zone 3.This pressor areas 2 is divided into two subareas; The long thermal treatment zone 4 of adjoining with preheating zone 3 and be in short cooling zone 5 after this thermal treatment zone 4.The thermal treatment zone 4 itself has three the sub-temperature provinces that can control separately mutually 41,42 and 43.In the front of the pressor areas 2 of double belt press 1, have a pair of heated inclination cylinder 6 and 6 that inwardly draws material ', these two cylinders have been mounted to sizable distance between mutually; In addition, after pressor areas 2, also have the inclination cylinder that is pulled outwardly material 7,7 of a pair of respective design ', and it is shorter to be mounted to mutual distance, after this is to the inclination cylinder that inwardly draws material, have several to support the support roller 11,11 that this double belt press 1 adds pressure zone 8 and 8 ' usefulness '.In order to keep temperature constant, utilize a pair of insulation board 9 and 9 ' block from add in the double belt laminating machine 1 pressure zone 8 and 8 ' heat, limit preheating zone 3 with this.The said pressure zone 8 and 8 ' be of adding is by the inclination cylinder 6 and 6 that inwardly draws material ' heating.This is made up of coldplate insulation board.Cooling worm made of copper is used in cooling, can be controlled at the coolant flow speed that this cooling is flow through in coiled pipe, can control temperature exactly like this.Also can use cooling device, replace this cooling worm with forward connection guide groove.Used insulation board 9 and 9 ' be installed into and can move by along continuous straight runs is so that the preheating zone of the controlled temperature system of making can shift near or away from this pressor areas 2, in other words, also can control the locus of preheating zone 3.

The operating principle of double belt press used herein is a foundation with the following fact, and promptly institute's applied pressure on the sheet material that moves continuously by this press is evenly distributed on the whole width of this piece sheet material, and pressure does not change in time yet.Even, the constant reason of pressure is, in the double belt press, pressure is through being installed in the pressure buffer pad (not drawing among the figure) on this press, be delivered to closed steel by this press and the sheet material synchronous operation of being processed add pressure zone 8 and 8 ' on, this steel adds pressure zone and also plays a part finishing machine simultaneously.What preferentially select for use is the pressure zone that adds that has relatively large quality (for example thickness is approximately 2 millimeters), guarantees excellent heat transfer.

The length of the thermal treatment zone 4 of this press 1 for example is 3 meters, and the maximum total length of whole double belt press 1 is selected 4 meters for use, that is to say that whole pressor areas length is expected to be 4 meters.The length of preheating zone 3 under this condition is preferably 40 to 100 centimetres.In the preferable specific embodiments that illustrates, the length of cooling zone 5 is 1 meter.

Front at the double belt press, two spindle formula unwinders 12 and 13 are installed, wherein each unwinder all has two spindle 14-17 that use around prepreg, and the prepreg that is twined is glass fibre (fabric fibre or cotton) or the quires layer that scribbles resin system; In addition, another one spindle formula unwinder 18 is installed also, two spindles of using around metal forming 19 and 21 are arranged on it.Between spindle formula unwinder 18 and double belt press 1, be equipped with metal forming directive wheel 22 and 22 '.

According to producer to, what be installed in double belt press back is trimming equipment 23 and is used to cut into the cutter sweep 24 that required size is used thereafter.

In operating process, four prepregs that is to say to scribble resin curing agent/coagulant system and by the laminated material of pre-hardening under the senior B state, pull out from spindle formula unwinder 12 and 13, are sent to preheating zone 3 together.3 these four layers of prepregs are heated under about 80～100 ℃ of temperature under the condition that is not stressed in the preheating zone, make resin system begin effect.Meanwhile, supply with metal formings by two spindles 19 on the spindle formula unwinder 18 and 21, these metal formings be directed under the condition of separating with those prepregs specific insulation board 9 or 9 ' and add pressure zone 8 or 8 ' between, before pressor areas 2, combine with those prepregs rapidly then.Though the preheating zone temperature was up to 100 ℃ (this point was pointed out), the cylinder temperature of feeding in machine is higher, and therefore the metal forming that is admitted in the machine is heated than prepreg temperature height.There are three sub-humidity provinces 41,42 and 43 thermal treatment zone 4 of pressor areas 2, which floor raw material that here combines, be increased to be pressed under about 190 ℃ condition by 150 ℃ and cover metal laminate at the pressure and temperatures that are higher than 25 crust, and, make it to be bonded together owing to still have the hardening of resin effect of reactivity.The temperature of the first sub-humidity province 41 is lower, and the second sub-humidity province, 42 temperature are higher; The latter's temperature can equate with the temperature of the 3rd sub-humidity province, is approximately 190～200 ℃.Covering metal laminate is cooled in cooling zone 5 subsequently under pressure.Add pressure energy in this complicated stage and stop quality to descend, particularly can prevent the product distortion.Be cooled to about 100 ℃ metal laminate that covers, begin to leave cooling zone 5 this moment.In trimmer 23 subsequently, prune from the both sides of covering metal laminate through the edge of pressurization, then on cutting machine 24 thereafter, be cut into needed size.

Between cooling zone and trimmer, can be provided for guaranteeing covering second heat-treatment zone of the base material constant dimension of metal laminate.

The equipment that illustrates preferably is to have in the thermal treatment zone 4 under the condition of certain holdup time and works, in this holdup time and the double belt press charging rate be about 3 meters/minute quite.Holdup time and charging rate depend on the reaction rate of employed hardening temperature and resin-curing agent-coagulant system.

When only producing single face and covering metal laminate, can use the stable on heating separating foil of a slice to replace metal forming, this separating foil is wrapped on the corresponding spindle and is admitted in the double belt press.Used this separating foil for example can be aluminium foil of crossing with siloxane treated or the aluminium foil that posts one deck polytetrafluoroethylene (PTFE).When through after the covering metal laminate and from the double belt press, send of machine-shaping, this separating foil can be extracted out from production board, reuse.

Be illustrated though process of the present invention is covered metal laminate with reference to six layers, have covering metal laminate and can certainly being made of different lamination numbers.

Illustrated operating condition depends on used resin system basically, and can make corresponding change.

Method and apparatus of the present invention not only can be used the copper lamination, and can come lamination with other metal forming.Method and apparatus of the present invention is particularly suited for producing the metal laminate that covers with composite metallic material, and for example the sort of Cu/Al of the having paper tinsel of high accuracy use in printed circuit board covers metal laminate (but but being what is called etching-spalling plate).

The present invention will be further specified by following examples:

Embodiment 1

With weight is 200 gram/rice ²The finished glass fabric, for example normally used the sort of glass fabric when making the glass fibre that is covered with Copper Foil of use in printed circuit board-epoxy resin laminate plate floods with certain resin solution.Used the sort of resin solution is made up of following one-tenth branch: contain 1～15%, preferably contain the bisphenol-A-glycidol ether of part bromination of 100 parts of polymerizations of 5～12% epoxidised phenolic resin varinishes, 3.2 part dicyano diamides, 0.25 part of 3-picoline and 80 parts of Propylene Glycols.Soak into this resin by this way and in 165 ℃ of dry prepregs of crossing, contained 42% resin and 10% resin flux.Seven this prepregs are preheated to 80 ℃, then temperature increases to 195 ℃ condition by 150 ℃ under, under 45 bar pressures, with present device with its Copper Foil with two 35 micron thickness, pressurize in the mode that moves continuously, make the double-sided copper-clad laminate plate of 1.5 millimeters thick.This double-sided copper-clad laminate plate is tested back proof, and this laminated plate has reached above-mentioned medium good standard unexpectedly aspect dimensional uniformity, and the character of others and traditional laminated plate are suitable.

The allowable deviation of obtained copper-coated laminated board thickness is ± 3/100 millimeter.As a comparison, the allowable deviation of stipulating in the copper-coated laminated board rigidity standard is ± 13/100 millimeter, and has utilized this numerical value fully with the made copper-coated laminated board of multidaylight press.

Embodiment 2

The sort of glass fabric with for example narrating in embodiment 1 soaks into resin solution.Used resin solution is made up of following ingredients: 100 parts wherein contain 1～15%, preferably contain 5～12% epoxidation phenol varnish gums and through the poly-bisphenol-A-glycidol ether of part bromination, 3.4 part dicyano diamides, 0.33 part of 4-dimethylamino naphthyridine and 80 parts of Propylene Glycols.Soak into by this way and under 170 ℃ of temperature the dry prepreg of crossing, contain 44% resin and 8% resin flux.Several such prepregs are preheated to 85 ℃, then temperature increases to 200 ℃ and 50 bar pressure conditions from 155 ℃ under, to make it with two thickness be 35 micron copper foils pressurizes in the mode that moves continuously with present device, makes thickness and be two two copper-coated laminated boards of 1.5 millimeters.Test with regard to the copper-coated laminated board of making in this example, found that its dimensional stability equates with above-mentioned standard value, and other performance and the conventional articles of laminate are suitable.

Embodiment 3

Weight is equaled 100 gram/rice ²And, soak into certain resin compound according to the glass fabric of purposes described in the embodiment 1.Employed resin compound contains following composition: 100 parts of polymerization bisphenol-A-glycidol ethers that wherein contain 1～15%, are preferably the part bromination of 5～12% epoxidised novolaks resins (wherein the epoxy resin equivalent is between 350 and 520), 3.0 part dicyano diamides, 0.40 part of 2-amino-4-picoline and 80 parts of Propylene Glycols.Dry down at 165 ℃ then.Resin content is 44%, and resin flux content is 10%.Two this prepregs are preheated to after 80 ℃, is 35 microns single face Copper Foil in the mode that moves continuously with a thickness, under the condition of using separating foil, pressurize with equipment of the present invention, the pressor areas temperature increases to 190 ℃ by 150 ℃, pressure is 50 crust, is 0.2 millimeter single face copper-coated laminated board to make thickness.Identical among the result who obtains after the check and the embodiment 2.

Embodiment 4-13

Embodiment 4-13 compositions for use or operating condition all are illustrated in below the table.

Table

(the continuous table of going up)

Claims (18)

1, a kind of continuous production is used for the method for covering metal laminate of printed circuit board (PCB), it is characterized in that:

To flood also with the short resin system that coagulates, prevulcanized laminated material sheet passes through a stress-free preheating zone continuously, these laminated material sheets are carried out preheating under not stressed condition, to reduce the viscosity of this resin, then the laminated material sheet that is impregnated with above-mentioned resin with this preheating combines with the metal forming of a slice preheating at least, send into the pressor areas of biobelt press then, in this district, under the temperature of pressure and rising gradually, above-mentioned laminated material sheet and metal forming are pressed together, thereby obtain a kind of metal laminate that covers of continuous length, this continuous metal laminate that covers is cooled off in the cooling zone, leave the cooling zone again, then cut the edge of both sides pressurized, be cut into required size at last.

2, method according to claim 1, the pressure that it is characterized in that said its pressor areas of pressure process are 25 to 80 crust, and temperature is for to increase to 210 ℃ from about 150.

3, method according to claim 1 and 2 is characterized in that covering process that metal laminate cools off and carrying out adding to depress in the cooling zone heating pressurization back is resulting, and said cooling zone preferably is within the double belt press.

4, method according to claim 1 is characterized in that the said metal laminate that covers stands heat treatment for the second time.

5, method according to claim 1, when it is characterized in that the production single face has the lamination base material of metal forming in said continuous processing, also a kind of separating foil is simultaneously sent at metal-foil-free, pressurization is then left behind separating foil after sending from the double belt press from the base material plate.

6, according to claim 1, the described method of any one of 2,4 and 5 is characterized in that said laminated material sheet and metal forming are separated preheating.

7, method according to claim 6 is characterized in that said metal forming is preheating to the temperature higher than laminated material sheet.

8, according to claim 1, the described method of any one of 2,4 and 5 is characterized in that in the said pressure process, just immediately said laminated material sheet and said metal forming is combined in the pressor areas front of press.

9, according to claim 1, the described method of any one of 2,4 and 5 is characterized in that employed laminated material sheet is to be impregnated with to be urged epoxy resin hardener/catalyst system with fixed attention and process precuring.

10, method according to claim 9, it is characterized in that containing in the short epoxy resin/curing agent/catalyst system that coagulates of the quilt that adopts in the said method from one or more compound of choosing next group material as coagulant, said material group contains substituted pyridine compounds class, imidazoles, substituted imidazoles, dicyano diamides and benzyl dimethyl amine.

11, method according to claim 10 is characterized in that containing coagulant or the accelerator admixture that is equivalent to solid epoxy resin weight 0.2～0.8% in said epoxy resin/curing agent/catalyst system of being urged to coagulate.

12, a kind of equipment of implementing the said method of claim 1, in order to the laminated material that will flood thermosetting resin with desire lamination metal forming thereon and be pressed into the metal laminate that covers, it is characterized in that wherein press is a kind ofly can will flood thermosetting resin continuously and be pressed into the heatable double belt press (1) that covers metal laminate through the laminated material and the metal forming of precuring under the condition of pressure and intensification as printed circuit board (PCB); Can supply with two spindle formula unwinders (12,13) of prepreg and the spindle formula unwinder (18) that another one can be supplied with metal forming continuously continuously in the installation of the front of this double belt press (1); A pressurized, heated district (4) is arranged in this double belt press (1) and be in cooling zone (5) afterwards, this pressurized, heated district (4), press preheating zone (3) for nothing in the front of pressurized, heated district (4); Near space nothing pressure preheating zone (3) has been installed separately laminated material sheet and metal forming guide device; Also have before in the pressurized, heated district (4) of double belt press (1) the inclination cylinder 6 and 6 of a pair of heated inside pellet ', also have the inclination cylinder that is pulled outwardly material (7,7 ') of a pair of respective design afterwards in this cooling zone (5), what be installed in double belt press (1) back is trimming equipment (23) and is used to cut into the cutter sweep (24) that required size is used thereafter.

13, double belt press according to claim 12 (1) is characterized in that being equipped with in the preheating zone (3) the but insulation board of degree (9,9 ') of a pair of controlled refrigeration.

14, double belt press according to claim 13 (1), it is characterized in that said insulation board (9,9 ') is installed into can the along continuous straight runs dislocation.

15, according to the described double belt press of each claim in the claim 12 to 14 (1), it is characterized in that in machine, drawing the distance between the pair of cylinders (6,6 ') of material, bigger than the distance of the pair of cylinders of outside machine, drawing material (7,7 ').

16,, it is characterized in that cooling zone afterwards, said pressurized, heated district (4) is the cooling zone (5) of a pressurization according to the described double belt press of each claim in the claim 12 to 14 (1).

17,, it is characterized in that the said thermal treatment zone (4) is divided into three the sub-humidity provinces that can control separately separately (41,42,43) according to the described double belt press of claim 12 to 14 (1).

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