DE19830038C2 - Solution and method for pretreating copper surfaces - Google Patents

Description

The invention relates to a solution and a method for pretreatment of Copper surfaces for subsequent formation of an adherent bond between the pretreated copper surfaces and plastic substrates. The Solution is preferably used for pretreatment of copper layers the PCB inner layers for the purpose of the subsequent formation of a haft firm bond between the PCB inner layers and PCB Resin resin layers and pretreatment of copper layers the printed circuit boards for adherent bonding of the copper layers with art existing resists.

In the production of printed circuit boards, various sub-processes go through performed in which copper surfaces adherent to an organic substrate ge need to be tied. In some cases, the required adhesion of the Ensured compounds formed over a very long period of time his. In other cases, a strong bond must be only temporarily, For example, if the organic substrate only during the manufacturing process ses the circuit board remains on the copper surfaces. For example, must the adherent bond of dry film resists used to structure the Conductor tracks on printed circuit boards are used, with the copper surfaces only during the Be guaranteed PCB manufacturing process. After the formation of the ladder The resists can be removed again.

The easiest way to increase the adhesive strength is to use the Etch copper surfaces before forming the compound while doing so roughen. For this purpose, microetching solutions, for example sulfuric acid Lö solutions of hydrogen peroxide or sodium peroxodisulfate.  

Another method is described in US-A-3,645,772. After that, a Pretreatment solution used for the copper surfaces, for example Contains 5-aminotetrazole.

A long-term stability is especially in the laminating process for Mehrlagenlei terplatten required. For these purposes are other pretreatment methods required for the copper surfaces.

In the manufacture of multilayer printed circuit boards, several printed circuit boards are used layers together with insulating synthetic resin layers (so-called prepregs: fiberglass reinforced epoxy resin films). The inner co The content of a laminate must be constant throughout the life of the conductor stay upright. For this the auflie on the inner layers must ing copper layers, preferably the Leiterzugstrukturen, superficially be treated. To solve this problem, various procedures have been adopted developed.

The one commonly used for pretreatment before lamination Method is to form an oxide layer on the copper surfaces. In this process known as black or brown oxide process set very aggressive reaction conditions for oxide formation. A disadvantage of the method is that ver the adhesion to the resin layer average oxide layer only a low resistance to acid, insbesonde hydrochloric acid, has treatment solutions, so that they can be used in subsequent processes sen for metallizing the through holes attacked in printed circuit boards and the bond to form delaminations of the attacked Positions are lifted again (pink ring phenomenon: visible from the outside Attack of the black oxide layer in the immediate vicinity of a hole in Circuit boards by discoloration of the originally black oxide layer, in the the pink copper layer of the inner layer can be recognized as an annular defect becomes; wedge void phenomenon: in a through a treated hole in ladder plates made cross section recognizable defect in the form of a gap between a copper inner layer and the adjacent circuit board resin  by the attack of acidic treatment solutions on the black oxide layer).

One solution to the problem described above is to use the oxide layer before the lamination process superficially reduce. The reduced Black oxide has opposite to that at the via of the passage holes used a higher stability than normal Black oxide. However, by the additional reduction step are erhebli costs. In addition, they are used for the reduction treatment baren chemicals against oxidation by air little resistant, so that the Service life of the baths and the durability of the additives chemicals limited are. This problem is to be solved according to JP-A-08097559 in that then the reduced copper oxide layers ver with a protective layer by treating them with an aqueous solution, in an aminothiazole and / or aminobenzothiazole compound is contained. However, on the one hand the cost problem of expensive reduction chemicals and their lack of oxidation resistance and on the other Also, the acid instability of the layer can not be completely eliminated.

Another possibility for adhesion mediation is the Kupferoberflä with an aqueous or alcoholic solution of an azole compound to treat. Such a method is for example from WO 96/19097 A1 known. Thereafter, the copper surfaces are treated with a solution, in the 0.1 to 20 wt .-% hydrogen peroxide, an inorganic acid, for example sulfuric acid, an organic corrosion inhibitor, for example Ben zotriazole, and a wetting agent are included. Due to the corrosive action of water peroxide, the copper surfaces are etched, so that mikrorauhe Ober surfaces arise.

To increase the adhesion of a photoresist layer on top of copper Surface is proposed in US-A-3,645,772, the copper surfaces before the Applying the resist layer with a solution to treat the nitrogen ent organic compounds containing at least one heteroatom which is derived from  Nitrogen is different, and with at least one five- or six-membered Ring contains. As nitrogen-containing organic compounds be. Be agreed compounds from the classes of thiazoles, benzothiazoles, imidazoles, Benzimidazoles, triazoles, benzotriazoles, naphthotriazoles, thiazolines, tetrazoles, Benzoxazole and benzanilides used. According to information in the document can also resist the resistance of a chemical Attack be reinforced by using these solutions.

Also, from US-A-4,917,758 etching solutions are known, but for Abdün serve copper cladding on the PCB materials. In the Solutions are also hydrogen peroxide, sulfuric acid and a Nitrogen-containing compound, preferably aminobenzoic acid, aminote trazol or phenylurea.

Further etching solutions are given in US-A-4,158,593 and US-A-4,140,646. These solutions for etching copper on printed circuit boards contain sulfur acid and hydrogen peroxide and inorganic compounds of selenium in the oxidation state + IV, preferably selenium dioxide, selenious acid or their Salts.

In US-A-3,801,512 u. a. with amidosulfuric acid, sulfoxides, sulfolanes, Sulfolenes and sulfones stabilized acidic hydrogen peroxide solutions be written, which are used for example for etching copper.

In US-A-3,770,530 etching solutions for copper, especially for use in Circuit board production, described the peroxodisulfate and additives to Increase the etching rate included. As additives are 1,2,3-triazoles, 1,2,4-tri azoles and tetrazoles proposed.

In Patent Abstract of Japan, C-1209, 1994, Vol. 296, JP 6-57 453 A are Etching solutions for copper described with which an etching process for the production of printed circuit boards without substantial lateral attack of copper surfaces possible  is. The etching solutions contain cupric (II) chloride, hydrochloric acid and 2-amino benzothiazole or its derivatives.

The present invention is therefore based on the problem, the Nachtei To avoid le of the prior art and in particular a pre-treatment solution and to provide a method of adherence from copper surfaces to plastic surfaces. The procedure should be simple, safe to use and cheap. It is also important that by treatment with the solution also a material compound is available, in successor processes in the manufacture of printed circuit boards, for example in the metallization of through holes in printed circuit board material, not leads to problems (pink ring, wedge void formation). Preferably, the Vor treatment solution therefore for use in Leiterplattenherstellverfah be used.

This problem is solved by the solution according to claim 1 and Be A method of action according to claim 18.

The solution according to the invention is used for the pretreatment of copper surfaces for the subsequent formation of an adhesive bond with plastic substrates and contains

• a) hydrogen peroxide,
• b) at least one acid,
• c) at least one nitrogen-containing, five-membered heterocyclic Compound which is not a sulfur, selenium or tellurium atom in the heterocycle has, as well
• d) additionally at least one adhesion-promoting compound selected from the group consisting of sulfinic acids, selenic acids, telluric acids, heterocyclic compounds which contain at least one sulfur, selenium and / or teleur atom in the heterocycle, as well as sulfonium, selenonium and telluronium salts the sulfonium, selenonium and telluronium salts are compounds having the general formula A.
  where A = S, Se or Te,
  R ₁ , R ₂ and R ₃ = alkyl, substituted alkyl, alkenyl, phenyl, substituted phenyl, benzyl, cycloalkyl, substituted cycloalkyl,
  wherein R ₁ , R ₂ and R ₃ are the same or different, and
  X ^- = anion of an inorganic or organic acid or hydroxide,
  with the proviso that for component b. selected acid does not match those for component d. selected sulfinic, selenic or tellurin acids is identical.

It should be selected adhesion-promoting compounds that are in the acidic, preferably sulfuric acid, solution has sufficient solubility sen.

To carry out the process according to the invention, the copper top surfaces were brought into contact with the solution.

The problem underlying the invention is particularly by the uses of the solution according to claims 19 and 20 solved. Thereafter, the aforementioned solution is preferably used for pretreatment of copper layers having printed circuit board inner layers for forming a Adhesive bond between the PCB inner layers and Kunstharzla gene as well as for pretreatment of copper layers having printed circuit boards for forming an adherent bond between the copper layers and out Plastics existing Resisten.

Preferred embodiments of the invention are in the subclaims specified.  

Preferred sulfinic acids are adhesion-promoting compounds having the chemical formula B

with R ₄ , R ₅ and R ₆ = hydrogen, alkyl, phenyl, substituted phenyl or R ₇ - (CO) - with R ₇ = hydrogen, alkyl, phenyl, substituted phenyl, wherein R ₄ , R ₅ and R _{6 are the} same or can be different
and aromatic sulfinic acids.

Preferably, formamidinesulfinic acid is an adhesion-promoting compound in the Solution included. As aromatic sulfinic acids may preferably benzenesulfine acid, toluenesulfinic acid, chlorobenzenesulfinic acids, nitrobenzenesulfinic acids and Carboxybenzenesulfinic acids are used.

As adhesion-promoting heterocyclic compounds are preferably thio phenes, thiazoles, isothiazoles, thiadiazoles and thiatriazoles used.

Suitable thiophenes are compounds having the chemical formula C.

with R ₈ , R ₉ , R ₁₀ , R ₁₁ = hydrogen, alkyl, substituted alkyl, phenyl, substituted phenyl, halogen, amino, alkylamino, dialkylamino, hydroxy, alkoxy, carboxy, carboxyalkyl, alkoxycarbonyl, aminocarbonyl, R ₁₂ - CONH- with R ₁₂ = hydrogen, alkyl, phenyl or substituted phenyl, wherein R ₈ , R ₉ , R ₁₀ and R _{11 may be the} same or different and part of condensed to the thiophene ring homo- or heterocyclic rings.

Particularly preferred thiophenes are aminothiophenecarboxylic acids, their Esters and amides. For example, 3-aminothiophene-2-carboxylic acid methyl be used advantageously ester.

Suitable thiazoles are compounds having the chemical formula D:

with R ₁₃ , R ₁₄ , R ₁₅ = hydrogen, alkyl, substituted alkyl, phenyl, substituted phenyl, halogen, amino, alkylamino, Dial kylamino, hydroxy, alkoxy, carboxy, carboxyalkyl, alkoxycarbonyl, aminocarbonyl, R ₁₆ -CONH- with R ₁₆ = hydrogen, alkyl, phenyl or substituted phenyl, wherein R ₁₃ , R ₁₄ and R _{15 may be the} same or different and R ₁₄ and R _{15 may be} part of a ring fused to the thiazole homo- or heterocyclic ring.

Particularly suitable thiazoles are aminothiazole and substituted aminothia Zole. Furthermore, preferred thiadiazoles are adhesion-promoting compounds the group consisting of aminothiadiazole and substituted aminothiadiazole len.

Further, as sulfonium salts, preferably trimethylsulfonium, Triphenylsulfonium, Methioninalkylsulfonium- and Methioninbenzylsulfonium salts used as adhesion-promoting compounds.

As nitrogen-containing, five-membered heterocyclic compounds that no Sulfur, selenium or tellurium contained in the heterocycle, monocyclic  and polycyclic fused ring systems are used. at For example, the compound may be a fused benzene, naphthalene or Pyrimidine ring included. For the selection of these compounds, please note that they should have sufficient solubility in the acidic solution. Preferably, triazoles, tetrazoles, imidazoles, pyrazoles and purines or their derivatives contained in the solution.

The solution contains in particular triazoles with the chemical formula E1

with R ₁₇ R ₁₈ = hydrogen, alkyl, amino, phenyl, substituted phenyl, carboxyalkyl, where R ₁₇ and R _{18 may be the} same or different and part of a homo- or heterocyclic ring fused to the triazole ring.

Particularly preferred are benzotriazole, methylbenzotriazole, ethylbenzotriazole and dimethylbenzotriazole.

In addition, the solution may contain tetrazoles having the chemical formula E2

where R _{19 is} hydrogen, alkyl, haloalkyl, amino, phenyl, substituted phenyl, benzyl, carboxy, carboxyalkyl, alkoxycarbonyl, aminocarbonyl, R ₂₀ -CONH where R _{20 is} hydrogen, alkyl, phenyl or substituted phenyl.

As a preferred tetrazole compound, 5-aminotetrazole and 5-phenyltetra used. As a preferred imidazole compound, benzimidazole is used.  5-aminotetrazole, 5-phenyltetrazole, benzotriazole, methylbenzotriazole and Ethylbenzotriazole are in particular because of their good solubility in the Vor treatment solution and preferred because of the easy availability Verbin fertilize.

Preferred combinations are benzotriazole, methylbenzotriazole, ethylbenzene zotriazole, 5-aminotetrazole and 5-phenyltetrazole as nitrogen containing hete Rocyclic compounds with aminothiophenecarboxylic acids, their esters and Amides, aminothiazole and substituted aminothiazoles as heterocyclic Links.

The inventive method provides an extremely simple Vorbe Treatment of copper surfaces for the subsequent adherent connection with Plastics safe. Essentially, only one process step is required Lich, namely the treatment of the copper surfaces with the inventive Solution for the subsequent formation of a composite with organic Substra The adhesive strength does not decrease even after a long time. Are the haftvermit not containing compounds in the solution can not be nearly as high bond strength of the composite can be achieved. In addition, the long-term stability of the composite after pretreatment with a solution that the invented Contains adhesion-promoting compounds according to the invention, essential worse than after using a solution containing the adhesion promoting Ver contains bonds.

In addition, those related to the metallization of Through holes in PCB problems, namely the Bil Formation of pink ring and wedge voids, through the use of these additional Compounds avoided in the pretreatment solution, as with the inventions adhesion-promoting layers produced according to the invention a ausge have excellent acid resistance, while black oxide (black oxide) and reduced black oxide layers against hydrochloric acid solutions a certain Have sensitivity. It has even been shown that the adhesive strength improve a composite with organic substrates in certain cases leaves when the copper surfaces after treatment with the inventive  Solution and before preparing the composite with dilute acid be treated. Preferably hydrochloric acid can be used for this purpose.

The advantageous effect of the solution according to the invention was surprising since also a sole use of adhesion-promoting compounds in the Pretreatment solution does not give the desired high long-term adhesive strength. By using both components of the solution, the copper upper discolors surfaces and lead to the desired properties. Furthermore, in Ver same experiments, it has been found that, in particular, sulfin, selenin and telluric acids are particularly well suited as adhesion-promoting compounds are.

For safe pretreatment, the copper surfaces are usually first cleaned. All conventional cleaning solutions can be used for this purpose become. Usually wetting agents and optionally complexing agents, For example, triethanolamine containing aqueous solutions used.

After rinsing the cleaned copper surfaces, these are inventions treated solution according to the invention. The copper surfaces are discolored forming an adhesion-promoting layer of pink in a brown tone, depending on the type of combination of nitrogen-containing, five-membered heterocyclic and adhesion-promoting compounds.

Due to the micro-etching effect of the hydrogen peroxide in conjunction with the Säu microrough copper surfaces are obtained because of the surfaces magnification an increase in the adhesive strength of Ver subsequently formed Federal between the copper surfaces and the plastic substrate made possible light. It is also believed that the adhesion of the following ge formed composite in addition to this surface enlargement by the Forming an organo-copper compound improves that is true apparently made of copper, the nitrogen-containing compound and the haftver forms a mediating connection on the copper surface. As acid is in the he inventive solution preferably inorganic acid, particularly preferred  Sulfuric acid. Basically, however, are other acids used.

To stabilize hydrogen peroxide against decomposition, the solution additional additional compounds, for example p-phenolsulfonic acid, and as Solvent water and additionally organic solvents, such as alcohols, contain, for example, the solubility of the constituents contained therein, in particular the nitrogen-containing, five-membered heterocyclic Ver compounds and adhesion-promoting compounds.

In addition, other inorganic and organic compounds in be included in the solution, for example, copper sulfate and wetting agents.

The treatment is preferably carried out at a temperature of 20 to 60 ° C carried out. The treatment time is preferably 10 to 600 seconds. ever the higher the temperature, the faster the solution works. Therefore If necessary, also significantly shorter treatment times can be selected become. From a practical point of view, however, is preferably a chosen medium temperature, for example from 25 to 40 ° C to the reaction to be able to control better. Mean treatment times are 20 to 90 seconds Customer. In addition, due to possible incompatibilities of certain Components of the solution at elevated temperature, for example because of increased temperature of poorly soluble wetting agents, the requirement to comply with an upper temperature limit.

The concentration ranges preferably set in the solution are:

Sulfuric acid, conc. 10 to 250 g / l Hydrogen peroxide, 30% by weight 1 to 100 g / l five-membered nitrogen-containing heterocyclic compound 0.5 to 50 g / l Adhesive compounds: sulfinic, selenic or telluric acid 0.05 to 10 g / l adhesion-promoting heterocyclic compound 0.5 to 25 g / l Sulfonium, selenonium or telluronium salt 0.01 to 10 g / l

The optimum concentrations of the aforementioned bath components depend on the type of nitrogen-containing, heterocyclic Verbindun conditions and adhesion-promoting connections.

After treatment in the solution according to the invention, the copper rinsed surfaces again, preferably with warm, deionized water. They are then dried, for example with hot air.

Optionally, the copper surfaces after rinsing with dilute acid be treated, preferably with 10 wt .-% hydrochloric acid or 10 wt .-% Sulfuric acid. Treatment times are from 5 seconds to 300 seconds it is useful. After the acid treatment, the copper surfaces become rinsed again, preferably with deionized water.

To increase the durability of the solution according to the invention, it is favorable, the Ready-to-use treatment solution shortly before the procedure is carried out rens. For example, hydrogen peroxide can be mixed with a sulfur acidic solution of the nitrogen-containing, heterocyclic and the Haftver mixing compounds or just before use already applied solution can be supplemented to the desired concentration to adjust the individual components.

The treatment of the workpieces having the copper surfaces can be done in usual diving systems are performed. In the treatment of ladder plates, it has proven to be particularly favorable, so-called passage systems in which the printed circuit boards on a horizontal Trans guided through the plant and thereby with the treatment solutions via suitable nozzles, such as spray or splash nozzles, in contact to be brought. The PCBs can do this horizontally or vertically or be held in any other orientation.

The following examples serve to further illustrate the invention:

example 1

An aqueous solution was prepared by mixing together the following constituents:

Sulfuric acid, 96% by weight 50 ml Hydrogen peroxide, 30% by weight in water 60 ml benzotriazole 10 g formamidinesulfinic 0.5 g AL = L <Make up to 1 liter with deionized water

The solution was heated to 40 ° C, and a copper foil (PCB quality, about 25 μm thick) was immersed in the solution for 60 seconds. After the Be The film was rinsed with warm deionized water and allowed to dry then dried. The copper foil had a brown hue.

The copper foil was then laminated to a prepreg (glass fiber reinforced epoxy resin film (FR4 resin), Type 2125 MT, Thickness 0.1, from Dielektra, DE) by heating the copper and prepreg sheets at a temperature of 175 ° C a pressure of 2.5. 10 ⁶ Pa ( Δ 25 bar) were pressed together.

The peel strength of the copper foil on the prepreg sheet was measured. It peel strengths of 9.9 to 10.6 N / cm were determined.

Examples 2 to 10

Example 1 was repeated in each case with a solution which always had the following constituents:

Sulfuric acid, 96% by weight 50 ml Hydrogen peroxide, 30% by weight in water 60 ml

and additionally the further constituents listed in Table 1 (heterocycli true S, Se and Te-free compound and adhesion-promoting compound). The prepared mixtures were made up to 1 liter with deionized water.

The treated according to Example 2 copper foil had a reddish hue. The Copper foils treated according to Examples 3 to 10 had a brownish color Hue up.

The peel strength was measured in each case as in Example 1. It the values for peel strength shown in Table 1 were obtained.

Example 11

A copper foil was treated as in Example 4, but the copper foil became before lamination at room temperature for 20 seconds with 10% by weight Treated hydrochloric acid and then rinsed with deionized water.

A peel strength similar to that of Example 1 was obtained (11.1 to 11.6 N / cm).

Comparative example

Example 1 was repeated, but with a solution in which none of the liable mediating compounds was included.

Only a peel strength of 3.6 to 4.0 N / cm was obtained.  

Claims (20)

1. A solution for pretreatment of copper surfaces for subsequent Bil the an adhesive bond between the copper surfaces and plastic substrates, containing

• a) hydrogen peroxide,
• b) at least one acid and
• c) at least one nitrogen-containing, five-membered heterocyclic compound which has no sulfur, selenium or tellurium atom in the heterocycle,

characterized in that

• a) additionally at least one adhesion-promoting compound from the group consisting of sulfinic acids, selenic acids, telluric acids, heterocycli's compounds containing at least one sulfur, selenium and / or tellurium in the heterocycle, as well as sulfonium, Selenonium- and telluronium salts where the sulfonium, selenonium and telluronium salts are compounds of general formula A.
  where A = S, Se or Te,
  R ₁ , R ₂ and R ₃ = alkyl, substituted alkyl, alkenyl, phenyl, substituted phenyl, benzyl, cycloalkyl, substituted cycloalkyl wherein R ₁ , R ₂ and R _{3 are the} same or different, and
  X ^- = anion of an inorganic or organic acid or hydroxide,
  with the proviso that for component b. selected acid does not match those for component d. selected sulfinic, selenic or tellurin acids is identical.

2. A solution according to claim 1, characterized in that sulfinic acids from the group consisting of compounds having the chemical formula B
with R ₄ , R ₅ and R ₆ = hydrogen, alkyl, phenyl, substituted phenyl, R ₇ - (CO) - with R ₇ = hydrogen, alkyl, phenyl or substituted phenyl, wherein R ₄ , R ₅ and R _{6 is the} same or are different,
and aromatic sulfinic acids. 3. Solution according to one of the preceding claims, characterized in that that formamidinesulfinic acid is contained as an adhesion-promoting compound. 4. Solution according to one of claims 1 and 2, characterized in that aromatic sulfinic acids from the group consisting of benzenesulfinic acid, Toluenesulfinic acid, chlorobenzenesulfinic acids, nitrobenzenesulfinic acids and carb oxybenzenesulfinic acids. 5. Solution according to one of the preceding claims, characterized in that that at least one adhesion-promoting heterocyclic compound from the Group consisting of thiophenes, thiazoles, isothiazoles, thiadiazoles and Thiatriazoles, is included. 6. A solution according to claim 5, characterized in that at least one thiophene from the group consisting of compounds having the chemical formula C is contained
with R ₈ , R ₉ , R ₁₀ , R ₁₁ = hydrogen, alkyl, substituted alkyl, phenyl, substituted phenyl, halogen, amino, alkylamino, dialkylamino, hydroxy, alkoxy, carboxy, carboxyalkyl, alkoxycarbonyl, aminocarbonyl, R ₁₂ - CONH- with R ₁₂ = hydrogen, alkyl, phenyl or substituted phenyl, wherein R ₈ , R ₉ , R ₁₀ and R _{11 may be the} same or different and may be part of condensed on the thiophene ring homo or heterocyclic rings. 7. Solution according to one of claims 5 and 6, characterized in that at least one thiophene from the group consisting of aminothiophencar acids, their esters and their amides. 8. A solution according to any one of claims 5 to 7, characterized in that at least one thiazole from the group consisting of compounds having the chemical formula D is contained
with R ₁₃ , R ₁₄ , R ₁₅ = hydrogen, alkyl, substituted alkyl, phenyl, substituted phenyl, halogen, amino, alkylamino, Dial kylamino, hydroxy, alkoxy, carboxy, carboxyalkyl, alkoxycarbonyl, aminocarbonyl, R ₁₆ -CONH- with R ₁₆ = hydrogen, alkyl, phenyl or substituted phenyl, wherein R ₁₃ , R ₁₄ and R _{15 may be the} same or different and R ₁₄ and R _{15 may be} part of a ring fused to the thiazole homo- or heterocyclic ring. 9. Solution according to one of claims 5 to 8, characterized in that at least one thiazole from the group consisting of aminothiazole and sub substituted aminothiazoles. 10. Solution according to one of claims 5 to 9, characterized in that at least one thiadiazole from the group consisting of aminothiadiazole and substituted aminothiadiazoles. 11. Solution according to one of the preceding claims, characterized in that in that at least one sulfonium salt is selected from the group consisting of trimethyl sulfonium salts, triphenylsulfonium salts, methionine alkylsulfonium salts and Methioninbenzylsulfoniumsalzen is included. 12. Solution according to one of the preceding claims, characterized in that in that at least one nitrogen-containing, five-membered heterocyclic Ver from the group consisting of triazoles, tetrazoles, imidazoles, Pyrazoles and purines, is included. 13. The solution according to claim 12, characterized in that at least one triazole is contained with the chemical formula E1
with R ₁₇ , R ₁₈ = hydrogen, alkyl, amino, phenyl, substituted phenyl, carboxyalkyl, wherein R ₁₇ and R _{18 may be the} same or different and part of a condensed to the triazole ring homo- or heterocyclic ring. 14. Solution according to one of claims 12 and 13, characterized in that at least one triazole is selected from the group consisting of benzotriazole, Me ethylbenzotriazole, ethylbenzotriazole and dimethylbenzotriazole.   15. A solution according to any one of claims 12 to 14, characterized in that at least one tetrazole is contained with the chemical formula E2
where R _{19 is} hydrogen, alkyl, haloalkyl, amino, phenyl, substituted phenyl, benzyl, carboxy, carboxyalkyl, alkoxycarbonyl, aminocarbonyl or R ₂₀ -CONH where R _{20 is} hydrogen, alkyl, phenyl or substituted phenyl. 16. Solution according to one of claims 12 to 15, characterized in that at least one tetrazole from the group consisting of 5-aminotetrazole and 5-phenyltetrazole. 17. Solution according to one of the preceding claims, characterized in that that for component b. in the solution sulfuric acid is selected as the acid. 18. Method for pretreating copper surfaces to the following Forming an adhesive bond of the copper surfaces with plastic sub straten, in which the copper surfaces with the solution according Ansprü 1 to 17 are brought into contact.   19. The method according to claim 18, characterized in that Kupferschich having printed circuit board inner layers to form an adhesive Verbun pretreated between the PCB inner layers and synthetic resin layers become. 20. The method according to claim 18, characterized in that Kupferschich th having printed circuit boards for forming an adhesive bond between pretreated the copper layers and resists made of plastics become.