SE435779B - COATED COPPER FILM COMPREHENSIVE ARSENIC CONTENT LAYER AND SET TO MAKE FILM - Google Patents

Description

g79oe2s2-7 10 15- 20 25 30 35 long-term heating, for example, a peeling strength of at least 0.357 kp / cmz after heat treatment during 56 days at 135 ° C. Although such durability with respect to de-on the peel strength after long-term heating natural largely depends on its characteristics the organic substrate of the film, that is, about it thermal destruction which is unavoidable to organs technical substances has been sufficiently reduced, this also depends on the treatment of the surface of the parfoil, which is bonded to the substrate.

With respect to residual peel strength after long-term heating, it can be mentioned that this strength is a property, which can not be measured according to the heat tests, t hitherto used in conventional standard tests on copper-plated laminates, for example soldering tests or peeling strength after heat treatment on a soldering bath for a period of between 5-20 seconds and several hours. For laminates prepared in the above-mentioned known manner most products fully meet the requirements of origin peel strength, adhesion between copper foil and organic adhesive layer and peeling strength after heating treatment for seconds or minutes, which so far generally required with regard to unilateral or bilateral sided copper foil coated laminates, for example blistering test during soldering, which means heat test at 2600 C for a few tens of seconds, or peeling strength after heat treatment in a solder bath for 5-20 seconds, or similar the. Most products that pass these tests lose however, all strength in the above test according to Unn standard, ie heat resistance at 153 ° c for 56 days, not to mention the remaining peeling strength of 0.357 kp / cmz. On the other hand, it has in the production of printed circuits are required, not only for the above-mentioned tests. without also as a problem in practice, that the copper foil as well shall have a sufficiently high residual strength after time heating. An example of this is laminate coated a variety of copper layers. In the production of such 10 15 20 25 30 35 7906252-7 layer laminate comes a double-sided sheet, as later forms an inner layer laminated by hot pressing, to be subjected to different treatments in the formation of the the risk circuits, for example the circuit design itself, drilling or punching, plating in through holes etc. Then additional, outer layers are placed on it prepared and treated copper foil laminate and compressed with this by hot pressing. When a multiple lamination is carried out two or more times, the the foil heats under pressure for several hours. This has the same effect as if heating in the temperature range those listed in the U.L. Standard are repeated several times, why the heating situation is completely different from the one that exists in the conventional tests at 2600 C below a certain number seconds in an open atmosphere.

In the production of such multiple layer laminates circuit boards are required, except for durability in the adhesion between copper foil and organic substrate laminate, density in the adhesion between the different metal layers, for example between copper foil and secondary electrolytically applied layers respectively copper layer and alloy layer, at the rolytic coating of copper foil by a variety of electrolytic treatments. The object of the present invention is to achieve one for printed circuits with high adhesion strength suitable coated copper foil with high heat resistance, for which purpose a coated copper foil according to the invention exists of a copper foil and a plurality of electrodeposited layers comprising an arsenic-containing copper layer, which precipitated on the copper foil and a plating layer, which consists of zinc and tin or alloy of at least one zinc and tin with copper, which electrodepositions directly on the arsenic-containing copper layer, the metals, which forming the various layers in the diversity includes further electrodeposited metal layers with a composition, at which the metals have diffused through each other.

A method of making a coated copper foil according to above is characterized by the following process steps: elëktrO * 10 15 20 25 30 35 7906252-7 precipitation of an arsenic-containing copper layer on the surface of a copper foil by means of an electrolyte containing grooves of arsenic, electrodeposition on this arsenic-containing copper layer of a plating layer consisting of zinc and tin or an alloy of zinc or tin with copper as well treatment of the material in the arsenic-containing copper layer and the plating layer so that they diffuse into each other.

In order to obtain a copper foil for printed circuits which is particularly suitable for the production of In layered circuits of the type mentioned above, it has been found to be no the stability of the bond between the metal surfaces is dependent of the two previously mentioned problems, that is heat resistance for a long time in the various secondary electrodeposited layers between them and in the organic the base substance in the laminated matrix. With this starting point point, detailed studies have been carried out with a focus on positively prevent copper transition thermally and physically or chemically from copper foil to the organic the base material during long-term heating, for example from heating at about 1700 C for one hour in the lamination pressure to over 56 days according to UL-Standard, and also with focus on maintaining adhesion between the layers when copper and copper-based alloy layers are exposed to route precipitation treatments. In doing so, it has been shown that in the former case a layer of a three-component alloy, consisting of three layers of tin, zinc and one under .diffusion of alloy formed by tin and zinc gives a very effective barrier against the transfer of copper from the surface to be formed to the organic base provides thermal stability during long time, and in the latter case to tight adhesion between copper layer with each other and between copper layer and copper clay layers are obtained on arsenic, which is otherwise avoided at electro-refining of copper according to old due to that it has given a raw surface, which is difficult to thermally treat, used. On this basis, surveys have been conducted to obtain a copper foil that satisfies the requirements according to UL-Standard and multilayer laminate. Results have been 10 15 20 25 30 35 7906252-7 confirmed that laminates of the above three-component alloy layers and arsenic-containing copper layers provide a synergistic effect, so that it was possible to obtain a copper foil that is resistant to the harsh long-term treatments.

The invention provides a very marked efficiency when it is a matter of carrying out continuous electrocoating of two or more layers on that surface of a copper foil to be treated, that is to say it surface of the foil, with which the latter is to be adhered to one base plate of organic material or other adhesion.

When the invention is applied for special surface area enhancement electrodeposition treatment, in which an electrodeposition., copper layers are obtained by overlying a plurality times, the density of the respective deposited layers is increased each time by means of an intermediate layer containing traces of arsenic. Furthermore, it is also possible to apply this in combination with techniques to prevent lami ~ stains, transfers or the like during manufacture of printed circuits, caused by physical or chemical transfer of copper, caused by the formation of bonding of secondary electrodeposited copper layers on contact below heat and with a large specific surface area, directly on a laminate of organic material, for example in lamination according to a technology that we have previously proposed and published in Japanese Offenlegungsschrift 74537/1977, according to which an electrodeposited layer of a binary alloy is applied to one copper foil, after which this treatment according to the Japanese the publication 111428/1977 can be followed by an heating to form a layer of a tertiary alloy.

In addition, it is possible to achieve residual peeling strength after long-term heating, which is not always the case safety has been achieved through the mere combination of these without at the same time the effect of the combination as such deteriorated. Thus, it has been possible to broaden the areas of application of copper-plated laminates, for example heat-resistant base materials, and also improve reliability in cases where the material has been used as inner copper foil in multilayer laminate for multiple circuits. 10 '15 20 25 'ao 35 1906252-7e The invention is further apparent from the following descriptions. in connection with the accompanying drawing, which illustrates a method of making a coated copy paraffin according to the invention. In the drawing, I I a first electrodeposition vessel in which a copper plate 7 tering is performed to form a fine particle layer which gives the copper foil a roughened surface. This surface does possible to bind the copper foil more firmly to a substrate.

The electrodeposited layer in this first treatment step may, if deemed necessary, be supplemented by a second, layers mentioned below and can also be dispensed with if the parfoil_as such has a surface suitable for adhesion. The fed copper foil 1 forms negative electrode in a bath In the carriage 1, connected to a kentectrul 2 with negative polarity, Before transporting down into the vessel I, the surface of the foil is cleaned in a washbasin 3 in acid bath {Med 4 denotes in electrolyte in vessel I and also in a number of the following vessels II-V immersed anodes. The copper foil passes through electrolytes in the vessels with the surface to be electrocoated facing the anodes.

In the different vessels the anodes 4 are connected to separate voltages. sources.

In the first step, the foil is treated with a current density in near the limit current or higher than this, so that you get a finely particulate surface, which increases the speoifika of the foil ytarea. For example, when using an acidic copper sulphate bath, it is possible to select the following operating conditions: cuso4 (calculated on kepper) '_ 12 - 20 g cu / 1 nH2SO4 45 and 120 g / l Solution temperature _ -_ o 22 -_35 ° C Current density (based on average _ cathode area) - _ 6 - l8 A / dmz Passage time 8? 25 s_ When the copper foil 1 has passed the first electrodeposition ningskärlet I o fl xvda ävwtryknullar electrodeposition vessel II, still covered by a lot 5 goes into a second thin liquid film to prevent oxidation, subjected the one in the second vessel II an electrodeposition, in which 10 15 20 25 30 35 7906252-7 7 an even copper layer precipitated, of which it in the first the step of deposited layer is prevented from falling off when the foil treated in the following treatment steps. The vessel in the vessel II the deposited layer is so thin that the roughened surface is maintained.

As an example of suitable data for the precipitation of this the following layers can be selected: CuSO4 (calculated as copper) '' 40 - 85 g Cu / l Hzsos' _ ~ _ g 40 -_ ~ izo g / i Solution temperature No. I 36 - 55 ° C Current density (average based on 'cathodic surface area)' 12 - 30 A / dmz Passage time 10 - 25 s Because the amount precipitated in the first step depends on current density, it is necessary to take into account traces of pollutants with transition valence, for example for example iron, chromium, arsenic, etc. and also for bathing setting and electrodeposition conditions, while in the second stage has considerably broader conditions and an precipitation at limit current density or lower, which gives a smooth plating on the surface.

Then the copper foil leaves the second vessel II and goes into vessel III for a third electrodeposition step then solution_from the vessel II has been removed with rollers 5 so that the the composition of the bath in vessel III not during the treatment will change significantly. U the third vessel an arsenic-containing copper layer is applied to improve the the adhesion strength of the copper foil and intermediate electrodeposited layers. For this purpose, prepare in advance an arsenic-containing solution.

As an arsenic source, for example, arsenic acid can be used in the form of an aqueous solution obtained by dissolving the acid in an aqueous solution of sodium hydroxide so that non-toxic arsing gas (AsH3) is formed. The composition of the bath in the third step and the precipitation conditions are shown in as an example: CuSo4 (calculated on Cu) 7 - 10 g Cu / 1- 7905252-1 10 l5 20 gzs 30 35 HZSO4 to - 70 g / l Added arsenic-containing solution (calculated pâyarsenik) z Solution temperature 18 f 22 ° C Current density (calculated on cathodic junction area on average) I 4 - 6 A / cmz Passage time s ~ zo s The applied arsenic-containing coupling layer at the third the precipitation step is applied so that it is present in the layer. 'the arsenic' must diffuse into the rough as well the copper surface layer as in a fourth electrodeposited layer, which in a subsequent step is formed on the arsenic-containing copper layer, so that an integration between the arsenic-containing the copper layer and the overlying and underlying layers achieved. Consequently, the thickness of the arsenic laminated copper layer does not necessarily have to be large, but it may be sufficient for such a thickness to be layered contains enough arsenic that can diffuse.

However, it should be with regard to the arsenic-containing the copper layer as the third layer is mentioned that alsocmnbad- and the electrodeposition conditions Q are set within those above mentioned limits, the arsenic content of the arsenic oily copper layer does not always have to be proportional on the other hand, but to some extent deviate depending on the surface conditions. those of the underlying copper layer or copper foil and differ significantly from the analytical values of a senic-containing precipitation that is obtained by electro-precipitation in a beaker test or the like with only this electrically precipitated layers. Furthermore, it may be mentioned that the thickness of it the arsenic-containing copper layer can be assessed using of its color by default._This color varies greatly from a color that is almost unchanged in relation to the color in pure electro-precipitated copper, when the thickness of the layer is very small, to black, depending on the layer thickness * increases until the acicular mass on the surface of the layer shoots out until it falls off. However, it is not necessary to produce layers of such thickness that the layer begins - 0.05 - 075 g As / l 10 15 20 25 30 35 7906252-7 loosen, but suitably select such a layer thickness that the color is within a range of gray-brown, in which the pair color to a considerable extent remains, to light brown color, then already the purpose of the layer in question has been fully achieved.

In the previous part of the description, the arsenic content the copper layer is mentioned as a third electrodeposition layers on a first and a second. However, an ar- senic-containing copper layer also electrodeposited directly on surface of the copper foil, however, it is desirable that the arsenic-containing copper layer is simultaneously given a surface roughening effect instead of surface roughening on copper the foil, the arsenic-containing copper precipitating until the thickness is such that the product gets a pale brown color.

When the layer has reached such a thickness, acicular protrusions are formed on the surface, which markedly increases the efficiency of the adhesion both for the copper foil and for an additional imposed alloy layer.

When the copper foil in the example now described has left electrodeposition in the third stage of vessel III and washing with sufficient water on both sides in a washbasin. vessel 6 and further washed on both sides by spraying with water so that arsenic-containing solution does not shall be mixed with a reducible metal bath in the following steps, it is inserted into a vessel IV for electrodeposition in one fourth step. If an arsenic association were to join the bath present in vessel IV, would be in danger for the formation of arsing gas, which makes thorough washing necessary. 'I The fourth precipitation step taken in vessel IV is intended to provide a pre-alloy layer of a zinc-tin mixture, which will later diffuse in in the arsenic-containing copper layer as a base to form an alloy layer during a subsequent drying of the copper foil, application and drying of adhesives, lamination pressing, etc. Regarding the treatment in the fourth the electrodeposition step may have the following processes based on two technical ideas are described with application to copper foil laminate.

The first relates to a method of electrodepositioning a 790625Ä-7 10 15 20 25 10 layer with the main focus on that complete prevent the transfer of copper and the other in one way I to apply thin alloy layers on both sides of one copper foil, so that the layers at the same time provide a corrosion protective effect. . ¿ In the first case, the electrodeposition can be performed , under the following conditions: 0.8 - 2.0 g / l (as Zn) ZnSO4 (denoted as Zn) Sn (SO4) 2 (calculated as Sn) 0.05 ~ 1.0 g / l (as Sn) K4P2o7-3H2o 20 - 40 g / l pH _ j 10.7 - 11.5 Solution temperature 40 - 480 C Current density (calculated on cathodic surface area, on average) 0.5 - 5.5 A / dm2 Passage time l0 ~ 25 s in Tin (II) sulphate can be used instead of tin (IV) - sulphate and zinc and tin can be used in the form of pyrophosphate barrel. 'I in In the first of the above cases, wherein it is necessary that the layer has a thickness that.sufficient: & k to safely prevent the passage of copper, one is selected thickness corresponding to pale gray color to such an amount that the copper color through which the bottom is visible, the layer thickness the game can be judged using the color change as one standard.

In the second of the above cases, the following precipitation conditions are stated: ZnSO4 (calculated as Zn)) 0 - 2.5 g / l (as Zn) SnSO4 (calculated as Sn) 0.1 - 2.5 g / l (as Sn) K4P2o7 15 - 50 g / l pH V l0.5. ~ ll.7 Solution temperature 40 - 48 ° C Current density (calculated on load side surface of the copper foil) 0.3 - 3 A / dmz 10 15 20 25 30 35 ï '7906252-7 ll Current density (blank side of ' copper foil) 0.05 - 2 A / dmz Uppehåustia 1 é 1o s Substitutions of zinc salt and tin salt can be de- ' same as mentioned in the first case. In addition, current-tight selected and assessed on the basis of the above-mentioned depending on the specific surface areas of both surfaces, the amount of current applied and the dio- tion of Zn-Sn in the copper surface at the next step and thereby arising appearance.

The vessel IV for the fourth precipitation step according to The illustration illustrates a case where a thin precipitation treatment ling is used on both surfaces to simultaneously get layers with anti-corrosion function, whereby an anode 7 is arranged in the middle of the vessel.

To prevent the surface-treated copper foil oxidized and stained during treatment necessary for manufacture of circuit boards; for example coating with adhesive and lamination, and during storage periods between the various steps, it is necessary to carry out a preventive treatment of it otherwise for the production circuit board surface-treated copper foil. After the fourth step is thus performed a fifth step of giving product corrosion resistance. If the above, i the second step process is used in the fourth precipitation of course, it is not necessary to implement take a fifth step to give the film corrosion resistance. density. However, this durability can be improved by treatment in a fifth step, Thereby one can apply one conventional method using organic antioxidants dants, for example triazoles, imidazoles, silane coupling agents, etc., but are preferably used a chromate in a fifth treatment step to achieve of corrosion resistance in combination with the above fourth electrodeposition step, which gives a synergistic effect with respect to the prevention of corrosion by Zn-Sn, which penetrated and remains together with chromate. This results in a highly efficient corrosion pyrazolones, 10 15 20 25 30 35 u Chromium trioxide solution ll79os2§2-7 12 durability. In the implementation of the chromate treatment as a fifth step, the copper foil is subjected thereafter fourth step a washing treatment with water, so that the bath in the fifth stage does not become contaminated.l l__ The chromate treatment can be carried out by using the foil immersed in a chromium oxide solution. Alternatively, you can reverse electrodeposition. Treatment with chromium trioxide solution can be implemented as follows: 0.3 - 3 g / l Residence time '10 - 2Q see __ In the case of chromate treatment during electrodeposition, the following conditions apply: Chromium trioxide solution 0.2 -0.6 g / l current density o, oz -f o, 2 li / amz Residence time 5 - 15 s i When both surfaces of the copper foil are exposed to cathodic bee action under the above conditions, it is possible 'to apply satisfactory corrosion prevention treatment on the electrically precipitated layer in the fourth step. _ The last step in the surface treatment of the copper foil after the above-mentioned fifth step is washing with water, pressing and drying. The last wash water should be deionized water, especially water that is free from chlorine ion. I i To save energy during drying, you can use an "air scraper" 9 or compression rollers 5 before drying ning. '_ When drying, it is advisable to use purified heat air. In particular, stable storage results are achieved for the following storage. products if the copper foil is dried at a temperature of between 60 and 1200 C for 30 s or longer with the electro- utfauaa layer of znêsn begins to aiffunaera aqh 1 certain extent forms alloy. In the drawing, one is indicated heating element 10, a cooling fan 11 and an apparatus 12 for winding up the foil. '' The application of the invention is not limited to 10 15 20 25 30 35 7906252-7 13 the example described here.

Using the invention, one can produce one product which is a copper foil with a larger or smaller diversity of electrodeposited layers obtained by electrodeposition precipitation of an arsenic-containing layer directly on copper the surface of the foil or on the surface of two or more electro- folded copper layers, and a plating layer; consisting of zinc and tin or an alloy of at least one of them with copper on the surface of the treated copper foil, and after storage for some time or heating provided at least one arsenic-containing copper layer, which has been applied between layers of copper and copper-based alloy, var- by the strength between these metal layers, they may the invention sought good properties.

The invention is further illustrated by the following example.

EXAMPLE 1 ~ Using a continuously operating surface treatment by means of which copper foil with a width of 1.1 m and a nominal thickness of 35 μm is treated, electrodeposition was performed as follows: Composition of the bath in the first treatment step CuSO4 (calculated on Cu) _ 14 g / l (as Cu) H2so4 _ «§_ 65 g / 1 Bath temperature 26 110 C The foil passed through the bath and was treated with one average current density on the cathodic surface of 12 A / dmz for about 13 s and then went to treatment ling in the second step.

Composition of the bath in the second treatment step CuSO4 (calculated on CU) 50 g / l (as Cu) HZSO4 Bath temperature 7o_g / 1 48 ° C The foil is passed through the electrodeposition vessel and is exposed for an average current density on the cathodic surface of 7906252-7 'ten 15 tzo 25 j- so 14 15 A / dm2 for 17 s and then passes over squeezing rolls to the third step, aar ae conditions as shown in the following Table l is maintained. ' table 1 Experiment No. 1 - A l - B l ~ C Cu concentration, g / l 8 _ 9 9.5 _ (marked on Cu) ' jn2sø4, g / 1 _33. 44 48 Asphaltic solution; g / l (calculated on As) 0.08 0.2 0.4 Bath temperature, ° c 21,: 0.5 19 1 0.5 1st: 0.5 Cathodic current density, I - A / amz 5, s i s 4 [s : uppehâ11stia, s_ '17 13 j 7' _ After the third step, the kdppar foil goes to the fourth via squeezing rollers, water shower, a water bath and a - additional shower.

For comparison, copper foil co-treated with L - A, B and C immediately for a chromate treatment without going through the fourth precipitation step. These equals leading examples are hereinafter referred to as 1-A (0), 1-B- (0) 1-C- (0). The rest was treated in the fourth step with one bath of the following composition: j and ZnSO 4 (calculated on Zn) 1.5 g / ll SnSO 4 (calculated on Sn) 0.6 g / l K4P2o7 34 g / l Bath temperature '46 1 l ° C 'pH _ 10.9 The precipitation treatment was carried out with an average catholic current density of 4.5 A / amz for 13 s. 10 15 20 25 30 35 _79oe2s2-7 15 a precipitate was formed, the thickness of which immediately after the installation was estimated at between 0.05 and 0.15 μm, whereby the presence of the layer was clearly discernible. After this fourth step, the foil was washed in water and showered and corrosion protection was treated on both surfaces.

Composition of the bath in the fifth treatment step Chromium trioxide 2.5 g / l Bath temperature 20 f lo C Current density on the fourth the step treated the surface 0 Cathodic current density on it blank surface o .03 A / dmz Then the foil had to go through squeezing rollers and washed first with tap water and then with deionized water on both sides and squeezed with rollers and dried. Insignificant amount of residual moisture was removed with hot air at 60 «65 ° C with" air knife ".

The foil was then passed through a drying zone with infrared heating. mare and compressed air at 1000 C for 80 s, after which it was dry, cooled in air stream and wound on a spool.

As a comparative example, a copper foil was prepared with omitting only the electrodeposition in the third step.

This comparative example is hereinafter referred to as 1- (0).

The various copper foils produced were press glued together 1700 C for one hour under a pressure of 17 kp / cmz with use of commercial, impregnated glass cloth of the type FR-4 intended for glass-epoxy-based copper-plated laminates, which was then subjected to assessment tests. Original peeling strengths, peeling strengths after heating on solder bath at 2600 C for 20 s, copper transition at the time for the measurement of the initial scaling strength, ' staining conditions after etching and changes in scale strength for each two-week period for 56 days at 1530 C is shown in Table 2.

The table shows that in terms of the general characteristics required by standard for standard copper-plated laminates, can also products, in which the process steps according to 7906252-7 10 the present invention has been omitted, having practically the same level as in treatment according to the invention, but as regards the durability of the peel strength after long-term heating are the products according to the invention 5 superior.a U 7906252-7 Q H.ov w ~. @ Wm.Q om.N mmn fl u m fl pmßux N «. ~ Q \ _ .UV O Q ^ Qv | u | H O H.ov mm. ° w ~ .H «m. ~ Mmn fi u mn wm_ ~ O \ Amv Q 0 ^ ov | m | H fl wv flfl O H.Qv ~ m.o øH.H w ~. ~ Mmn fl u nmuwmn H ~. ~ O \ Amy 0 Q ^ ov | «| H Hm.o mm. ° mw. @ NH.H oH. ~ Nwma fl: mmc fi om. ~ Q ÅHV Aov Q 0 uu fi m @. ° øm.o @@. o @ ~ .H wo. ~ mwmn fl .nwmc fl «H. ~ Q AHV Amy O O ml fi > m_ø H> .o ow.o wH.H øo. ~ nwmn fi nwwø fl wø. ~ Q AHV A fl v Q Q <| H 0 fl. Ov m «.o« m.H «H. ~ nmmn fl awmø fi ~ H. ~ 0 fifl v H 0 O .cvl fl m om u ooww mc fl cwm fl uw fl mw mn flfl mßw E0 \ mM wm Nw wm wa dxnhuw Hwßmm mnmm mxnæum fl ääm uww fi s Hwøcø Hwv flfl Hmø flfl | .fl HmMm .fl MUmHm.uw> ß | fl U.% fl Hmxw .OHR2 mwum mmum mwvm mmuw ao \ mx .o omm fl H fifi u .naHm> nmma flfi. lmm fl Hwumw mxumummm flfi n fi mxw nw fl msmn Pm wm m wnwmëwb> oHm .> 0Hm wUcmH © mEmm S00 H Homñwxw Qu flflfi m Qmm flfi d flfi mmm fl um flflfl o w flfi ow> ø m flfl G> onm N H fi wnmü 10 15 20 25 7906252-7 l8 Example 2 A treated copper foil was prepared under the same procedure. conditions as in Example 1, except that the conditions in the fourth electrodeposition step it was changed to that the following bath composition and precipitation conditions applied: Composition of the bath in the fourth treatment step ZnSQ4 (calculated on Znf '_l, 0 g / l SnSO¿ (calculated on Sn) _ 0.9 g / l KZPZO7 .fl g / l The bath temperature was 420 ° C and the pH was adjusted to 11.2.

In this bath, copper foils washed with water were introduced after the third step and was subjected to a protection treatment by precipitation of Sn-Zn layers on the treated and the glossy surface at an average current density of l, l A / dmz calculated on the surface of one side below about 3 s. The samples thus obtained are referred to below 2-A, 2-B and 2-C corresponding to the treatment conditions in the third rose. For comparison, an experiment was conducted with foil, for which the electrodeposition treatment in only the third step omitted. This test is called 2- (0).

The different copper foils were laminated on the same laminate. züngsbas as in Example 1 and subjected to the same test as in Example 1. The results are shown in Table 3.

As shown in Table 3, the effect achieved is according to the present invention does not depend on the thickness of the fourth layer, but is due to a synergistic effect between the arsenic-containing copper layer as the third layer and the plating layer as the fourth layer. 19 7906252-'7 | o ... H-GV wN-o oH-a mmfn: wmc fl Gmmn fi .Oo.N O KNv. . \. o. 0 AOV l N nio Noó 3.0 omr ».med owo fi aooo fi Sd o Qv So o o o .. w Ro. “Oo Qno Hou ... ooà ooooo ooooo mod o nu. m: o. o. o »N . Éo ood oïo 3A oorm owoš. ooooo moá o So 9: - o .. o o. ..- N m om.

U oowm ïm _ ” on fi nøma _. cmæm. fl www: www fl mmv Hwumw flfl ømuw W Enímx . wm Nw wN ._ wa .mxumvm nwvmw wcmmw mxuæum Qo fi w HwUGD Hwø fl b Hww fl b. HmmšD L fl amxw .Åšom fi h .Hmšßäö .... | .Qamv fl m IOHHQM mwwm mwvw mwvm mwßm . -. _. . ._. . . auäš .u ammo 34.3 Äauuw fl, _ nmmø Hwuuw mxwl fi mwmn fifl adxm. _ Hmm flflfl w fl m fl wn bm. wm fl mnwwñmb _> 0nm .bonm wø fl mnmmñm fi 300 N .fi ømšwxw ßm flfi mw Qmm flflfi ø fi wmm fl umä fifl w m fifl ou> m mn fi mboum m HHMQMH. 7906252-7 10 15 20 25 30 35 20 Exemgel 3 e_ An electrolysed copper foil with a thickness of 35 μm and the width 1.1 m was unwound from a spool and passed over an electric contact roller for power supply and was subjected to electrodeposition, with it being roughened surface provided side constituted cathode, using Å the following bath composition: ' cuso4 (calculated on cu) 9 g / l HZSO4 19 g / l Added arsenic-containing solution (calculated on As) 0.3 g / l Bath temperature 180 C The foil fish go through the bath at a cathodic current-tight 4.3 A / dmz for 13 s. The foil thus treated by squeezing rollers, washed thoroughly with water shower to remove each trace of As and then received go through a vessel for precipitation of tin-zinc alloy as Plating. _ å This bath for applying a plating layer which fourth layer had the following composition: ZnSO4 (calculated as Zn) 2.2 g / l SnSO 4 (calculated as Sn) 0.9 g / l Bath temperature 45 and 20 C The foil was coated on both sides at one cathodic current density of 1.3 A / dmz for about 7 s the resulting layer also has the effect of preventing corrosion layer.

The foil was then washed with water in a water tank. and in water shower to remove excess zinc salt etc. (the precipitated metallic tin does not dissolve removed during the dissolution of Zn), dried with an air knife and then had to pass through a drying zone with compressed air and infrared red element at 1100 C for about 90 s, after which it -I cooled with cold air and purged. The foil thus obtained hereinafter referred to as s-A. 3-15 denotes a product in 10 20 7906252-7 21 prepared with the addition of 2.5 g / l chromium trioxide to the wash water tank to provide corrosion protection with chromate. In addition, a sample (3) was prepared for comparison by using only electrodeposition of the arsenic nik-containing copper layer with the omission of plating layer but treatment with a 1% solution of benzotriazole, which is a known anti-decolorizing agent, under 15 seconds with subsequent washing with water and drying.

A comparative sample (4) is a product obtained using chromate treatment as corrosion protection for the above-mentioned 3-B instead of the triazole in the leading example (3). The copper foils thus obtained were coated with commercial adhesives, which are most suitable for respectively foils, manufactured by manufacturer M and manufacturer respectively E, accompanied by drying, so as to obtain adhesive foils, of which laminates are formed with glass fiber reinforcements lined epoxy sheets. The products produced were exposed to samples similar to those of Example 1 and the results are shown in Table 4. ' The advantages of a copier treated according to the invention parfolie is clearly shown in Table 4, even when the method applied directly to the surface of an untreated film of electro- small cups. 22 S: Nm ... 36 QÄ of ïå>>> oum c äämä šwå šw šwå mämnäm fi m o. \ E: \ \ .Hwwsww TS mm ... 3.0 get 3A S; . Kai 0 b. Šwá šwå Em ššå mmq fi uopm z så \ S: \. \ .Umwamn MAN ¶WN.o ~ @ _ ° @@. O °> .H Qw ^ @>. H ¶,. : wma fl n šâv šmá Bio šßå än šwâ âm fiäm fi m o ä, E. \ \ fn fi mm: feel mmá Éà gå ¶ Q; 3A å; _ nwmødê šáv Río šäé ÉÉH Bm šßå ñænâm fi m H A3 ä: \ \ »n fl mma w ¶ Q m M m m m Eo \ M1 QS ua .Häm w N H . U omm Mwwø: mxnæum .nt 9. m w m m m äämm äå fi: må w mc fl mwn fl: nwuëä »A293 me m .w Ehöm mä må mä .fl šw .SME Hwßmw umä m flfi .wa "O æ U mm fl w fi> .nßumnmmd mxnmum m flfl n | wG5Hmm HH "w ü Hmm flfifl w fl msmn Hwuowmfmxumummmø fi c fl mv fi m ... adšw .pøummwm 3.6. Fe c A å. Wm fl wuwmemw 7906252-7 7.> OHm ww fl mhnmëmn nämm ww fl mumw flfl um fi x fi øumu uum soc m fl wmämxm umwa fl m Qmm fifl nn fi wmmmø um fififi w w fi aom> m mQ fi n> 0Hm w A fl wnmß

Claims (8)

A layered copper foil for printed circuits, consisting of a copper foil and a number of layers of electrodeposited on the copper foil, characterized in that the layers comprise an arsenic-containing copper layer which is electrodeposited on at least one side of the foil and a plating layer, consisting of zinc and tin or an alloy of at least either zinc or tin with copper, which is electrodeposited directly on the arsenic-containing copper layer, the metals forming the respective layer and any further electrodeposited layers having compositions in which the metals dif - thought through each other. 2, Copper foil for printed circuits according to claim 1, characterized in that the copper foil is layered on both side surfaces. Copper foil for printed circuits according to one of the preceding claims, characterized in that the plating layer consists of 10-100% by weight of tin and the remainder zinc. 4. Copper foil for printed circuits according to any one of the preceding claims, characterized in that the surface on one or both sides of the copper foil coated with said layer is provided with an electro-precipitated, finely particulate copper layer and a smooth copper plating electrodeposed over this layer. 5. Copper foil for printed circuits according to any one of claims 1-4, characterized in that the layered copper foil has an outer layer, which is treated with anti-corrosion with a chromate. 6. A method of producing a layered copper foil for printed circuits, characterized in that an arsenic-containing copper layer is electrodeposited on the surface of said copper foil using an electrolyte containing traces of arsenic, then on said arsenic-containing copper layer electro-790625 -7 24 precipitates a plating layer, consisting of zinc and tin or an alloy of at least either zinc or tin with copper and then causes metals forming the latter layer and the arsenic-containing copper layer to diffuse into each other. 7. A method according to claim 6, characterized in that the diffusion is effected by heating the coated copper foil to 1000 C or higher. 8. A method according to claim 6 or 7, characterized in that the latter electrodeposited layer is subjected to a corrosion protection treatment with a chromate or an organic antioxidant.