NL7905675A - COPPER FOIL FOR PRINTED CIRCUITS AND METHOD OF MANUFACTURING THESE. - Google Patents

Description

t *

^ ^ Q

1 TO81TU Ry.dLE

1 '1 7 SEP. 1979

Copper foil for printed circuits and method for the manufacture thereof.

The invention relates to a copper foil for printed circuits and a method of manufacture. 4 of them. For the surface treatment of copper foils, general electrodeposition has already been proposed to double the specific surface thereof, while various other methods have also been proposed, such as a simple electrolytic powder fence coating; a two-step treatment to prevent the powder layer deposited by the aforementioned method from falling off the foil, furthermore applying a so-called smooth galvanizing layer to the above-mentioned coating at the boundary current density or lower; a method of applying a synthetic resin slurry in place of the above electrolytic powder coating to improve the tack properties; and a method of adding a colored salt of metals, such as arsenic, antimony, bismuth, etc., to a copper galvanizing solution thereby to obtain a finely roughened surface, as well as certain modifications associated with the aforementioned methods. Furthermore, in addition to these lamination methods, a method has been proposed in which simultaneously with the aforementioned bonding properties improving treatment, an alloy layer mainly composed of brass is electrolytically deposited on the surface of a copper foil, so as to cause errors caused by a physical or complex avoid chemical transfer of copper to the organic material, such as the base material. such as lamination discoloration, so-called discoloration, transition spots, which often occur during the necessary etching step for the. circuit pattern, using a copper-clad laminate as a printed circuit.

However, to the extent that the applications for printed circuit boards have increased and a high degree of effectiveness is required, the requirement has also been imposed that, in addition to their flame-retardant properties, the deterioration of the peel off 790 56 75. s * 2 strength after a long heating time small. is. According to the so-called

UL standards (as surance laboratories) which are generally recognized, require that. the peel strength after a long heating time, e.g. heating for 65 days at 153 ° C, maintained at 0.357 kg / can or 5 higher. Although such a maintenance of the peel strength after long heating obviously depends strongly on the properties of the organic substances of the laminated base material used for this purpose, whereby the inevitable thermal decomposition of the organic substances will be limited to a minimum of 10, the lifespan strongly depends on the surface treatment of the copper foil.

The residual peel strength after prolonged heating is a property which cannot be measured. The thermal tests used in the usual standard tests for copper-clad laminate, for example, the solder blow test or the peel strength after heating by a. solder bath for 5-20 sec or for hours. In. in the case of the laminates obtained according to the aforementioned prior art, for example, most products thereof meet the initial peel strength, the adhesion between copper foil and the adhering organic base layer as well as the peel strength after a heating history of sec or minutes, which specifications have been so far commonly prescribed for one or two surfaces with copper-clad laminate; such as the solder blow test which is a thermal test at 260 ° C for 10 sec or the peel strength after heating on a solder bath for 5 - 20 sec or the like type of test.

In the case of the aforementioned UL standards e.g. however, the heat resistance test at 153 ° C for 56 days, however, most products lose almost all of their residual strength after a few days to 2 weeks, let alone their residual peel strength of 0.357 kg / cm.

In addition to the aforementioned tests, it is currently also required in the manufacture of printed circuits that the copper foil has a sufficiently high residual strength after prolonged heating. Multiple copper clad laminates are a representative of 7905675 c. * * 3 image thereof. In the manufacture of these multilayer laminates, a two-surface sheet, which will later form the internal layer, is laminated by a hot press and. subjected to various treatments such as circuit formation, pressing and punching, electroplating holes, etc. Then the external layers are further applied thereto, followed by hot pressing. When the multiple lamination has been performed in two or three times, the copper foil is heated under pressure for several hours. This gives the same results as in the case where the heating in the temperature range defined by the UL standards is repeated several times, hence the heating conditions may differ differently from the usual conditions of 260 ° C and different seconds to differ. - the tens of seconds. In an open atmosphere.

In the production of these laminated multilayer plates, no consideration has been given to. the adhesion retention. thereof on the laminating organic base, a strong bond between the resp. metal layers, such as between copper foil and. secondary electrolytically deposited layers »de resp. copper layers and the alloy layers often required For the electrodeposition of copper foil by means of a multiple electrodeposition, which depends on the heating and pressure

It is an object of the invention to provide a copper foil for printed circuits with a high adhesive strength which is resistant to long-term heating. The invention now provides a copper foil for printed circuits, consisting of a copper foil with a plurality of layers electrolytically applied thereon, comprising an arsenic-containing copper layer, electrolytically deposited on the copper foil, as well as an electrolytic coating layer consisting of zinc and tin or an alloy. of at least zinc and / or tin with copper, directly electrolytically applied to the arsenic-containing copper layer, which metals containing the resp. layers of the plurality of electrolytically deposited layers form such compositions that the metals diffuse into each other. It is another object of the invention to provide a method for manufacturing the aforementioned printed circuit copper foil wherein this method is characterized by electrolytic. depositing an arsenic-containing copper-5 layer on the surface of a copper foil using an electrolyte containing a trace of arsenic; then it. electrolytic deposition on the copper layer of a galvanizing layer consisting of zinc and tin or an alloy of at least zinc and / or tin with copper, after which the metals forming the galvanizing layer and the arsenic-containing copper layer are diffused into each other.

Figure 1 provides a schematic overview of the production method of the invention.

In research to obtain. a copper foil for printed circuits that is most 'suitable' for. forming multilayer circuits as mentioned above has been found that the heat stability of the metal interfaces is related to the aforementioned problems, i.e. the long-term heat stability of the resp. secondary electrolytically deposited interlayers and of the organic laminating matrix base. It has been examined whether it was possible to positively prevent copper after a prolonged heating, e.g. after heating ranging from about 10 ° C for one hour in press lamination to more than 56 days according to UL standards, thermal, physical, or complex-cheraic transfers from the copper foil to the organic base material; In doing so, there has also been sought to maintain the bond strength between layers at the time when the copper and copper-based alloy layers are subjected to overlapping electrode deposition treatments several times. It has been found that, in the former, a three-component alloy layer consisting of three layers of tin, zinc and an alloy formed by diffusion is very effective as a barrier or barrier layer to the transition of copper from the surface to be attached. to the organic basis, in terms of long-term heat stability and that of the latter if arsenic, which has long since been rejected in the electro-refining of carbon 790 5 6 75 5 t 1 per because it has a rough surface or gives a surface layer which is thermally difficult to treat, is used positively * the strong mutual adhesion of the copper layers and which are retained between the copper layer and the copper alloy layer. Based on this finding, studies have been conducted to obtain a copper foil that meets the requirements of UL standards and multilayer laminates, i.e., the requirements for adhesion and lamination on one. printed circuit board with high peel strength after prolonged heating, confirming that in the case of the laminated structure of the above three-component alloy layer and arsenic-containing copper layer, in addition to the desired effect, a synergistic effect is achieved by both Thus, a copper foil is provided which is durable. relative to the aforementioned severe long-term conditions and processing as well as a method of manufacturing the same.

The invention is particularly effective in the case where an electrolytic coating of two layers or more in a multiple stage coating is applied continuously to the surface of a surface to be treated. copper foil, that is, the surface on which the foil is to be later adhered to an organic base or an adhesion. Namely, when used in an electrodeposition treatment to increase the specific surface, whereby an electrolyte. precipitated copper layer is obtained by depositing a layer several times, the bond strength between the resp. electrolytically deposited layers reinforced each time by an intermediate layer containing a trace of arsenic. It is furthermore also possible to combine this with techniques for combating lamination spots such as discolouration, spots, over-courses, etc. in the manufacture of printed circuits, resulting from physical or complex chemical transfer of copper caused by hot contact bonding. active copper layers of secondary electrolytic deposition with a large surface area, directly on a laminating organic base material; in the la-35 mination, e.g. a technique applied previously proposed in 790 56 75 -¾ · - s · λ; · ν ... · '-. 'λ / 6

Japanese Patent Publication 7-5337 / 1977 * wherein a binary alloy layer is electrolytically deposited on a copper foil; followed by heating to form a tertiary alloy layer, a technique proposed by Japanese Patent Publication 111 ^ 28/1977 · 5 It is further possible to maintain the peel strength during prolonged heating, which is always not easily possible without the use of electrodeposition techniques without the Affecting Effectiveness of This Combination of Techniques * Thus, it has become possible to broaden the fields of application of copper-clad laminates 10 such as the use of foam-resistant base materials and also to improve reliability in the case of these laminates being an internal copper foil of a multi-layer, multiple printed circuit laminate is used.

The invention will. now in. the following drawing will be elucidated.

Reference numeral 1 shows a first stage electrolytic plating vessel. wherein copper electroplating is performed to form the finely divided roughened surface on a copper foil. It is possible by this surface roughening to adhere the copper foil more firmly to the base. The first stage and the second stage electrode deposition layer as mentioned below can be attached or omitted as necessary depending on the surface condition of the copper foil. Supplied copper foil 'T is negatively charged via an electrical supply contact roller 2, the metal surface of which is purified in an acid washing vessel. Reference numeral b shows an anode, while a copper foil passes through an electrolyte with its electrolytically coated surface facing the anode U. This anode b. .is connected to various electrical supply systems. each barrel. In this step 3Q, it is generally treated with a current density at the limit value or higher to obtain a finely divided area and thereby increase the specific area. In the case of acidic copper sulfate baths it is h.v. select the following conditions: 790 5 6 75 7 «* Η

CuSOi (expressed in copper) 12 + 20 g / l (as

Cu) H 2 SO 4 5-120 g / l

Solution temperature 22 - 35 ° C

Current density (based on 5 on cathodic current surface, average) 6 - 18 A / dm ^

Duration 8-25 sec.

Copper foil 1, after passage through vessel I of the first stage, passes through press rollers 5 and enters a second electrolytic coating vessel II of the second stage, while maintaining a liquid film of minimum thickness to prevent oxidation. electrolytic "fence" handling in the second stage is electroplating one. smooth copper layer which is carried out to prevent the first stage electrolytic coating layer formed by electrolytic "coating carried out for roughening the surface" of the copper foil in the first stage electrode deposition vessel I when "falling down" the foil in the subsequent resp. treatment steps are used; thus, a thin plating is performed from -20 such that the roughened surface is maintained. As for the plating conditions or the composition of the plating, the current density, etc., the following example can be given.

CuSO ^ (expressed as copper) ^ 0 - 85 g / l (as Cu) 25 · 2S0k UO - 120 g / l

Solution temperature 36 - 55 ° C

Current density (based on specific cathode surface, average) 12-30 A / dm ^ 30 Lead time 10-25 sec.

Since the thickness of the electrolytic coating is strongly influenced by the current density, in the first step 790 56 75 8 it is necessary to pay attention to the presence of traces of transition metal impurities such as iron, chromium, arsenic etc. as well. the wax composition and the electrodeposition conditions, while in the second stage the conditions are markedly broader and an electrodeposition he. the · limit current density or lower, which has a smooth coating © p it. surface, gives, may be sufficient.

Be copper foil after. leaving the second stage had enters an electro-deposition vessel een of a third 1Q stage, removing 1 excess solution, by pressing on press rollers 5. such that the amount of solution is not less than that necessary for the liquid film, in order to prevent the solution from transferring to the connecting stage, whereby the wax composition would vary widely in this stage.

In the third stage vessel, an arsenic-containing copper layer is added to improve the resp. bond strength of the copper foil and the various electrolytically deposited layers present between them. For this purpose, an arsenic-containing solution is prepared in advance and then added.

Arsenic acid, e.g. used as an arsenic source and this is used in the form of. an aqueous solution obtained by dissolving it in an aqueous solution of sodium hydroxide to prevent it. harmful arsenic gas (AsH ^) is being developed.

As to the third stage had composition and the electrodeposition conditions. the following example <can be chosen:

CuSO ^ (expressed as Cu) 7 - 10 g / l (as Cu)

HgSO ^ 20 - 70 g / l (as & s) 3Q Added arsenic-containing

solution (expressed as arsenic) 0.05 - 0.5 g / l Solution temperature 18 - 22 ° C

Current density (based on specific cathodic surface, 35 average) ^ - 6 A / cm 2 7905675 * «9

Lead time 5-20 sec.

The arsenic-containing copper layer applied to the electrolytic coating of the third stage is applied for the purpose that the arsenic contained therein diffuses into the copper layer with the roughened surface as the base and is formed as a fourth electrolytically deposited layer on the arsenic. containing copper layer in the subsequent stage, allowing integration of the arsenic-containing copper layer with the above-mentioned above and. underlayers are attempted- As a result, the arsenic-containing copper layer is not necessarily very thick, but has such a thickness that the layer contains a sufficient amount of it to be able to diffuse. It should be noted that with regard to the arsenic-containing copper layer as the third layer, the arsenic content in the arsenic-containing copper layer is not. always 15 times proportional thereto, even when the bathing conditions and the electrodeposition conditions are in. the above areas are set, but the arsenic content in. differs to some extent depending on the surface condition of the copper layer or the copper foil as a base, and that. it differs greatly from the analytical value of a. arsenic-containing precipitate obtained by electrodeposition in a beaker test, etc. with this electrolytic deposited layer alone. Also, the thickness of the arsenic-containing copper layer can be assessed using its color change as standard. The color of. the arsenic-containing copper layer varies widely from a color, which is almost unchanged from that of the electrolytically coated copper layer alone, under certain circumstances in the case of a small thickness, to a black appearance resulting from the fact that when the thickness of the arsenic-containing copper layer increases, the needle-shaped fabric on the surface of the layer protrudes so strongly from the surface that it falls down. As for the arsenic-containing copper layer, it is not necessary to increase its thickness so that the projection of its surface grows until it falls as mentioned above, but 790 56 75 *. · · * - 10 if the color is limited to within an area of a gray-brown color, in which the copper color is substantially maintained, to a pale yellow chocolate color, then the target of third electrode deposition layer has been fully achieved. In the aforementioned description, the case has been discussed in which the arsenic-containing copper layer is applied as a third electrode deposition layer to the two first and second secondary electrode deposition layers. Af—. depending on the purpose and type of the. printed circuit boards, and if only the retention of peel strength after long-term heating is envisioned, however, the arsenic-containing copper layer can be directly electrolytically deposited on the surface of the. the copper foil, omitting the first layer and / or both the first and second layers.

In this case, however, it is desirable that. the arsenic-containing copper layer simultaneously has a surface roughening effect, instead of the surface roughening of the copper foil, and the arsenic-containing copper layer is electrolytically deposited until a thickness corresponding to the light brown color is obtained.

When the layer has such a thickness, a needle-shaped projection grows on the surface. which leads to a considerable effectiveness by improving the adhesion to the. copper foil, as well as "alloy" of the fourth stage as described below.

The copper foil leaving the third stage electrode deposition vessel III is washed with a sufficient amount of water on both surfaces thereof, in a water wash vessel 6, and further washed on both surfaces thereof with water spouts to mix the arsenic-containing solution in avoid a reductible metal bath in the next step and then an electrode deposition vessel IV. from the fourth stage. If an arsenic source is contained therein, there is a risk of arsenic gas being generated in an acidic reducible atmosphere, so that adequate water scrubbing is necessary. "

The fourth stage vessel IV is an electrode deposition vessel for the manufacture of. a zinc-tin mixture alloy layer which is later diffused into the arsenic-containing copper layer as a base to form an alloy layer, at the time of drying the copper foil, applying and drying an adhesive, and further laminating, pressing and bonding etc.

Fat concerns the treatment in vessel IV of the fourth stage, the following methods can be considered based on two technical ideas, taking into account the adaptability of copper foil to the opposite laminate, through a certain sensitivity, which as affinity between the two can be considered:

The first is directed to a method of electrodeposition of an alloy layer. the main aim of which is to completely prevent the transition of copper and the second is directed to a method of applying thin alloy layers to both surfaces of the copper foil, the layers simultaneously having an anticorrosive function.

The electrolytic coating according to the first method can be carried out under the following electrodeposition conditions:

ZnSO ^ (expressed as. Zn) 0.8 - 2.0 g / 1 (as Zn)

SnfeOj ^ g (expressed as Sn). 0.05 -1.0 g / 1 (Sn) ΚΗΡ20γ.2320 20 - hO g / 1 pH 10, T - 11.5

25 Solution temperature U0 - b8 ° C

Current density (based on specific cathode surface, average) 0.5 - 5.5 A / dm2

Throughput time 10-25 sec.

Tin (II) sulphate can also replace tin (IV) sulphate and zinc and tin can be used in the form of pyrophosphate.

In the case of the first method, a thickness of 790 56 75 5 «*: * - * 12 is chosen corresponding to a light gray color, such that the copper color is visible as hasis color, since it is necessary that the layer be of sufficient thickness to certainly prevent the transition of copper, while the layer-5 thickness is judged by noticing the color change. thereof, as standard.

In the case of the second method, the following electrodeposition conditions can be applied:

ZnSO ^ (expressed as> Zn) 0 - 2.5 g / 1 (as Zn) TO SnSO ^ (expressed as Sn) 0.1 - 2.5 g / 1 (as Sn) κ ^ ρ2ο7 15 - 50 g / 1 pE T0.5 - 11.7

Solution temperature ^ 0 - U8 ° C

Current density (treated 15 surface side of copper foil) 0.3 - 3 A / dm2 (gloss surface side, i.e. glossy side) 0.05 - 2 A / dm Throughput time 1 - 10 sec.

The substitutions of. zinc salt and tin salt are the same. as in the first method .. The current density can be chosen within the aforementioned conditions, depending on the specific surfaces of both surfaces, the amount of electricity supplied and the diffusion of Zn - Sn 25 in the copper surface in the next stage and the appearance on that time of day.

The fourth stage vessel IV illustrates the case where a thin electrolytic coating is applied to both surfaces, the layer being simultaneously one. anticorrosion-30 has the function of providing an anode 7 at the center of the vessel.

To prevent the surface-treated copper foil from oxidizing and discoloring during the steps necessary for the production of printed circuit boards, such as an adhesive coating step, a lamination step following the aforementioned surface treatment of the copper foil, and during the storage period between the respective stages it is necessary to carry out an anti-rust treatment on the surface-treated copper foil mentioned * Thus, the electrodeposition of the fourth stage follows an electrodeposition of the fifth stage that focuses on rust protection. If the above second method is used in the electrode position of. the fourth stage 10, of course, it is not necessary to carry out the treatment of the fifth stage. However, in order to increase the anti-rusting effectiveness, the treatment of the fifth stage can be carried out with. carried out successfully. As for the anti-rust method, a common method can be to use organic antioxidants. ' such as triazoles, pyrazolones, imidazoles, silane coupling agents etc. are used, but preferably an overlapping anti-rusting method using a chromate is used, as treatment of the fifth stage which is combined with the aforementioned electrode position of the fourth step, which leads to a synergistic effect of rust inhibition by means of. Zn - Sn that is permeated and remains with the chromate. A very effective rust-inhibiting effectiveness can thus be obtained. In carrying out the fifth stage chromate treatment, the copper foil subjected to the fourth stage process is pre-washed with water to sufficiently prevent impurities from entering the fifth stage treatment.

With regard to chromate treatment, a method in which the. foil is simply immersed - anhydrous 3Q chromic acid can be used. Where desired, an electrodeposition can also be used. When immersed in anhydrous chromic acid, the following conditions can be applied.

Anhydrous chromic acid 0.3 - 3 g / 1

Liquid transmission time 10-20 sec.

790 56 75

lU

The following electrodeposition conditions can be applied to chromate treatment via electrodeposition:

Anhydrous chromic acid 0.2 - 0.6 g / l p 5 Current density 0.02 - 0.2 A / dm

Transfer time 5-15 sec.

When both surfaces of the copper foil. subjected to a cathodic treatment under the aforementioned electrodeposition conditions, it is possible to apply an adequate anticorrosive treatment to the electrodeposition layer of the fourth stage.

The final stage of the superficial treatment of the copper foil following the aforementioned fifth stage electrode position consists of water washing, pressing and drying. The end-15 wash water is on. preferably deionized water, in particular water without chlorine ions. For energy savings at the drying stage, an air knife 9 or press rollers 5 · are used, followed by drying.

As for the drying method, it is preferable to use hot air after purification. Particularly when the copper foil is dried at a temperature of 60 DEG-12 DEG C. for 6 sec. Or longer and thereby during this treatment the electrolytically coated layer of Zn-Sn begins to diffuse as the fourth stage layer and to some extent an alloy stabilized results are obtained on subsequent storage and processing steps. Reference numerals 10, 11 and 12 show a heater, a cooling fan and a take-up reel.

The method of the invention is not limited to the aforementioned five-stage coat treatment.

If the product obtained is a copper foil with a plurality of additional electrolytically applied layers obtained by direct electrodeposition of an arsenic-containing copper layer on the surface of a copper foil or on the surface of a copper foil which is 7905675 tr -φ 15 one or two times electrolyte has already been coated. thereafter electrolytically deposited on the surface of the obtained copper foil a layer consisting of zinc and tin or an alloy of at least zinc and / or tin with copper, and after the whole has been left standing or heated, wherein at least one arsenic-containing copper layer is present between the copper layer and the copper-based alloy, the strong adhesion between these different metals is maintained and the object of the invention is achieved.

The invention will now be illustrated by the examples.

Example I

Using a continuous surface treatment device with which a copper foil with a. width of 1.1 meters and a nominal thickness of 35 micrometers was supplied, the treatments from the first through the fifth stage were successively carried out.

Treatment conditions are as follows:

First stage bath composition 20 CuSO ^ (expressed as Cu) 14 g / 1 (as Cu)

HgSO ^ 65 g / 1

Bath temperature 26 + 1 ° C

The foil is passed through the bath for about 13 seconds and electrolytically coated at an average current density on a cathodic surface of 12 A / dm, then sent to the second electrode deposition vessel.

Second stage bath composition

CuSO ^ (expressed as Cu) 50 g / 1 (as Cu)

HgSO ^ T0 g / 1

30 Bath temperature kQ + 1 ° C

The foil is passed through the electrodeposition vessel and electrolytically coated at an average current density on the cathodic surface of 15 A / dm for 17 sec. And then 7905675 16 sent via press rolls to the third stage electrodeposition vessel in which the three conditions are shown in Table A. were used.

TABLE A

5 Test 'No._1 - A_1 - B_1 - C__

Cu concentration 8 g / 1 9 9.5 (expressed as Cu) E2S0k (g / 1) 33 g / 1 kk k8 TO As-containing solution 0.08 g / 1 0.2 09k (expressed as As)

Bath temperature · (° C) 21 £ 0.5 ° C 19 + 0.5 ° C 18 + - 0.5 ° C

. Cathodic current density (A / drn ^) 5 »5 5 k, 5

15 Lead time through electrodes. 17 1-3 T

(sec)

The copper foil after leaving the third stage electrode deposition vessel was sent to the fourth stage electrode deposition vessel via light press rollers, a spray water bath, a water wash vessel and a spray water bath.

As comparative examples, the copper films were subjected to the 1-A, B and C treatments, directly subjected to a chromate treatment without entering the fourth stage electrode deposition vessel. These comparing examples are resp. called 1-A- (0), 1-B— (o) and 1-C- (o). The others were subjected to the fourth stage treatments under the same conditions.

The composition and conditions of the fourth stage bath were as follows: 30 ZnSO 2 (expressed as In) 1.5 g / l (as Zn)

SnSO ^ (expressed as Sn) 0.6 g / 1 (as Sn) V207 3k δ / 1

Bath temperature k6 ° + 1 ° C

pH measured by a pH-35 meter was 10.9.

7905675 m π

The electrodeposition was performed with an average cathodic straw density of k5 A / dm for 13 sec.

As a result, a precipitate amount (assumed as 0.05-0.15 micrometre just after the "coating") in which the presence of this layer was clearly visible was obtained. In this fourth step treatment, the obtained film was evaporated in a water washing vessel and sprayed with water after which an anti-rust treatment took place on both surfaces.

Composition of the bath of the fifth stage 10 Anhydrous chromic acid 2.5 g / l

Bath temperature 20 ° C + 1 ° C

Flow from the treated surface in the fourth stage 0 Gloss surface cathodic o 15 current density 0.03 A / dm.

The resulting film was passed through press rollers and then introduced into a water wash zone in which it was washed with operating water, then washed sufficiently with deionized water on both surfaces, squeezed between rolls and then sent to a drying zone. The small amount of residual moisture absorbed after pressing was further vented with hot air at 60 ° -5 ° C from an air knife. The resulting film was passed through a drying zone with an infrared heater and forced convection, at an ambient temperature of 100 ° C, for 1 minute and 25 seconds. After complete drying, the film was air-cooled by a slow fan and then taken up on a wrapper.

As a separate comparative example, a copper foil with the third stage electrode position omitted was prepared. This comparative example is called 1- (0).

The following obtained the aforementioned method, resp.

copper foils were pressed together at 100 ° C for an hour under a pressure of 17 kg / cm, using a commercially impregnated glass cloth, FR-k grade glass epoxy base, to produce copper-clad laminates, which were then - 750 56 75 18 throws of evaluation tests. The resp. initial peel strengths, peel strengths after heating in a solder bath "at 260 ° C for 20 sec, transition at the time of measuring initial peel strength, discoloration conditions, after etching, and change in peel strength after every two weeks for 56 days at 153 ° C are shown in Table B.

The table indicates that what. the general requirements set in the standards for conventional copper clad laminates, even products the steps of which have been omitted from the process of the invention, can reach almost the same level as those of the aforementioned embodiments, but in terms of retaining peel strength after prolonged heating, the products of the invention are better.

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Example II

A treated copper foil was obtained with the same samples and under the same conditions as in Example 1 except that only the conditions of the fourth stage electrodeposition were varied, i.e., the bath composition and the electrodeposition conditions.

The fourth stage bath composition was as follows:

ZnSO ^ (expressed as Zn) 1.0 g / l 10 SnSO ^ (expressed as Sn) 0.9 g / l k: 2p2ot 2T g / l

The bath temperature was 42 ° C and the pS was adjusted to 11 ', 2. In this bath copper foils were led washed with water (spraying and immersion in the vessel) after the third stage, after which an anti-rust Sn - Zn layer . electrolytically on the treated surfaces and gloss surfaces at a current density (averaged at the cathodic surface) of 1.1 A / dm / one side of the surface and deposited for an electrode lead time of about 3 seconds. The samples thus obtained were named 2-A, 2-B and 2-C, corresponding to the third stage treatment conditions. Separately, as a comparative example, a test in which only the third stage electrode position was omitted was performed.

The obtained sample was named 2- (0).

25 The resp. copper foils were laminated on the same lamination base as in Example I and subjected to the same tests as in Example I.

The results are shown in Table C. As can be seen from Table C, the effect of the invention does not depend on the thickness of the fourth layer, but results from the ayergistic effect of the arsenic-containing copper layer as the third layer and the galvanizing layer as the fourth layer.

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790 56 75

Example III

22

An electrolysed copper foil (thickness 35 micrometers, average width 1.1 m) was unwound from a coil, passed through an electric contact roller to supply electricity and subjected to electrodeposition with the cathode on the roughened surface side provided (no surface) and the following bath composition was used:

CuSO ^ i 9 g / 1 (as Cu) H2S <\ -19 g / 1 1 o Added arsenic-containing solution (expressed in As) 0.3 g / 1 (as As)

Bath temperature 18 ° C

The foil; was passed through bath 13 for 13 seconds at a cathodic current density of 0.3 A / dm. The obtained. copper foil was passed through press rolls, rinsed sufficiently with water to remove any traces of As and then passed through a tin-zinc. alloy electrosis position vessel,

The bath for the fourth layer was as follows: 20 InSOj ^ (expressed as Zn) 2.2 g / l (as Zn)

. SnSO ^ (expressed as Sn) 0.9 g / 1 (as Sn) Bath temperature Uj> ° + 2 ° C

The foil was electrodepositioned on both surfaces for about 7 seconds at a cathodic current density of 1.3 A / dm. At the same time, the obtained layer had the function of anti-rust layer.

The foil was then washed with water in a washing vessel and rinsed with water. remove excess Zn salt (electrolytically precipitated tin metal is not dissolved during zinc washout), hydro-extracted with an air knife and then passed through a forced convection drying zone (using a conventional infrared heater at an atmospheric temperature of 110 ° C) for 1 minute and 7905675 for 23 seconds, followed by cooling with cold air and recording on a wrapper. The obtained film is called 3A. 3B, the product is obtained by adding 2.5 g / l anhydrous chromic acid to the water ash vessel to provide a chromate anticorrosive function. Furthermore, comparative sample (3) is the product obtained by conducting only the electrodeposition of the arsenic-containing copper layer, leaving out the galvanizing layer, immediately immersing it in a 1 # 1s solution of benzotriazole, known as anti - discoloration agent, for 15 seconds, followed by washing with water and drying.

Comparative Example (k), the product was obtained by using the chromate rust-spring treatment of the aforementioned 3-B product in place of the. triazole rust-15 inhibitor of the comparative sample (3). The adhesives thus obtained were coated with commercial adhesives most suitable for each (M and E Company), followed by drying to obtain copper foils with adhesives, from which the laminates were made with pre-impregnations for FR-2 and FR -3. The product obtained and were subjected to the same tests as those of Example 1. The results are shown in Table D. As can be seen from Table D, even when the method of the invention is applied directly to the surface of an untreated electrolyzed copper foil, a particular favorable result obtained.

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Claims (4)

1. Printed circuit copper foil consisting of a copper foil 9 a plurality of additional electrodeposition layers comprising an arsenic-containing copper layer electrolytically deposited on at least one of the surfaces of the copper foil to be treated, as well as a direct electrolytic on the arsenic-containing copper layer deposited galvanization layer consisting of zinc and tin or an alloy of zinc and / or tin with copper, the metals forming the respective layers of the multiple additional electrolytically applied layers having such a composition that the metals are in each other diffuse » Foil according to claim 1. characterized in that both foil surfaces are treated. Film according to claims 1 - 2, characterized in that the galvanizing layer consists of 10 - 100% by weight of tin with 15 as the remainder of zinc. k. Foil according to claims 1-3 », characterized in that the surfaces of the copper foil to be treated are two-stage treated surfaces which have an electrolytically deposited, finely divided copper layer and an electrolytically deposited, smooth copper galvanizing layer overlapping on the first copper layer contain. Foil according to claims 1-3, characterized in that an outer layer is present on the copper foil which has undergone a rust-preventing treatment with a chromate. 25 6 »Method for manufacturing a copper foil for printed circuits, characterized by: electrolytically depositing an arsenic-containing copper layer on one or both surfaces of the copper foil to be treated by means of an electrolyte: which contains a trace of ar-30 '; electrolytically depositing on the copper layer an electroplating layer consisting of zinc and tin or a 79056 75 alloy of zinc and / or tin with copper, after which the metals which form the last layer and the arsenic-containing copper layer are diffused into each other. T Method according to claim 6, characterized in that the diffusion is carried out by heating to a temperature of 100 ° C or higher. 8. Process according to claims 6 - T, characterized in that the electrolytically deposited and treated layer is subjected to an anti-rust treatment with a chromate or an organic antioxidant. 7905675