Abstract Copper and copper alloys, in particular copper-coated laminates, are etched by immersing them in or spraying them with a solution of cupric chloride and regenerating the formed cuprous chloride during continuing operation by adding hydrogen peroxide and hydrochloric acid to the etching solution, the amount of the addition being controlled by measurements of the redox potential by means of a redox electrode and the control being adjusted to add predetermined amounts of the said two additives whenever the copper-I-ion concentration reaches a predetermined value, preferably 0.4 g/l so as to maintain a constant etching speed. An apparatus for use in this method comprises a tank for the etching solution, means for applying the solution to the copper or copper alloy material, a redox electrode immersed in the said tank, supply vessels for holding the regenerating additives, a conduit between said supply vessels and the tank, valve means for passing the regenerating liquid from the supply vessels to the tank and control means for operatively connecting the valve means to the redox electrode.
A METHOD FOR CONTINUOUSLY ETCHING COPPER CONDUCCTIVE PLATES WHICH COMPRISES CONTACTING THE COPPER CONDUCTIVE PLATE TO BE ETCHED WITH AN ETCHING SOLUTION OF CUPRIC CHLORIDE (COPPER (II) CHLORIDE) AND REGENERATING THE ETCHING SOLUTION CONTAINING CUPROUS CHLORDE (COPPER (I) CHLORIDE) FORMED IN THE ETCHING BY REACTION BETWEEN SAID COPPER CONDUCTIVE PLATE AND SAID ETCHING SOLUTION BY INTRODUCING HYDROGEN PEROXIDE AND HYDROCHLORIC ACID INTO SAID ETCHING SOLUTION, THE AMOUNTS OF HYDROGEN PEROXIDE AND HYDROCHLORIC ACID INTRODUCED BEING REGULATED BY CONTINUOUSLY MEASURING THE REDOX POTENTIAL OF SAID ETCHING SOLUTION BY MEANS OF A REDOX ELECTRODE AND AUTOMATICALLY INTRODUCING SAID HYDROGEN PEROXIDE AND HYDROCHLORIC ACID WHENEVER THE CUPROUS ION (CU(I) ) CONCENTRATION IN SAID ETCHING SOLUTION EXCEEDS 4 G/L IN AN AMOUNT AT LEAST SUFFICIENT TO REDUCE SAID CUPROUS ION (CU(I) ) CONCENTRATION BELOW SAID VALUE WHEREBY THE CUPROUS ION CONCENTRATION IS CONTINUOUSLY MAINTAINED BELOW SAID VALUE AND A CONSTANT ETCHING SPEED IS MAINTAINED.
Claim 2
Independent Claim
150 words
A METHOD FOR CONTINUOUSLY ETCHING COPPER CONDUCCTIVE PLATES WHICH COMPRISES CONTACTING THE COPPER CONDUCTIVE PLATE TO BE ETCHED WITH AN ETCHING SOLUTION OF CUPRIC CHLORIDE (COPPER (II) CHLORIDE) AND REGENERATING THE ETCHING SOLUTION CONTAINING CUPROUS CHLORDE (COPPER (I) CHLORIDE) FORMED IN THE ETCHING BY REACTION BETWEEN SAID COPPER CONDUCTIVE PLATE AND SAID ETCHING SOLUTION BY INTRODUCING HYDROGEN PEROXIDE AND HYDROCHLORIC ACID INTO SAID ETCHING SOLUTION, THE AMOUNTS OF HYDROGEN PEROXIDE AND HYDROCHLORIC ACID INTRODUCED BEING REGULATED BY CONTINUOUSLY MEASURING THE REDOX POTENTIAL OF SAID ETCHING SOLUTION BY MEANS OF A REDOX ELECTRODE AND AUTOMATICALLY INTRODUCING SAID HYDROGEN PEROXIDE AND HYDROCHLORIC ACID WHENEVER THE CUPROUS ION (CU(I) ) CONCENTRATION IN SAID ETCHING SOLUTION EXCEEDS 4 G/L IN AN AMOUNT AT LEAST SUFFICIENT TO REDUCE SAID CUPROUS ION (CU(I) ) CONCENTRATION BELOW SAID VALUE WHEREBY THE CUPROUS ION CONCENTRATION IS CONTINUOUSLY MAINTAINED BELOW SAID VALUE AND A CONSTANT ETCHING SPEED IS MAINTAINED.
Claim 3
Dependent Claim
26 words
Method according to claim 1 wherein hydrogen peroxide and hydrochloric acid are automatically introduced into said etching solution whenever the cuprous ion concentration exceeds 0.4 g/l.
Claim 4
Dependent Claim
26 words
Method according to claim 1 wherein hydrogen peroxide and hydrochloric acid are automatically introduced into said etching solution whenever the cuprous ion concentration exceeds 2 g/l.
Claim 5
Dependent Claim
25 words
Method according to claim 1 wherein said hydrogen peroxide and hydrochloric acid are introduced in a molar ratio of 1:2 hydrogen peroxide to hydrochloric acid.