Etchant with increased etch rate

Claim 2

A process for the manufacture of a printed circuit board comprising the step of contacting a copper clad printed circuit board base material, having an etch resist over the surface of the copper defining a circuit pattern, with an etchant for a time sufficient to remove all exposed copper, said etchant comprising an aqueous solution of a peroxide and sulfuric acid, each in an amount sufficient to provide a sustained rate of etching, and propionic acid in an amount sufficient to exalt the etch rate to a rate in excess of that achievable by the peroxide-sulfuric mixture alone.

Claim 3

The process of claim 1 where the propionic acid is present in an amount sufficient to double the etch rate relative to said etchant free of the carboxylic acid.

Claim 4

The process of claim 1 where the peroxide content varies between about 0.5 and 2.5 moles per liter.

Claim 5

The process of claim 1 where the concentration of the propionic acid ranges from about 0.1 to 2.5 moles per liter of solution.

Claim 6

A process for dissolving a copper containing metal comprising contact of the copper metal with an etchant that is an aqueous solution of a peroxide and sulfuric acid, each in amounts sufficient to provide a sustained rate of etching of the copper metal, and a low molecular weight carboxylic acid in an amount sufficient to exalt the etch rate to a rate at least double that achievable with the peroxide-sulfuric mixture alone.

Claim 7

A process for dissolving a copper containing metal comprising contact of the copper metal with an etchant that is an aqueous solution of a peroxide and sulfuric acid, each in amounts sufficient to provide a sustained rate of etching of the copper metal, and a low molecular weight carboxylic acid in an amount sufficient to exalt the etch rate to a rate at least double that achievable with the peroxide-sulfuric mixture alone.

Claim 8

The process of claim 5 where the copper metal is contacted with the etchant for a time sufficient to dissolve a copper layer having a thickness of at least 0.1 mils.

Claim 9

The process of claim 5 where the peroxide content varies between 0.5 and 2.5 moles per liter.

Claim 10

The process of claim 6 where the carboxylic acid conforms to the general formula: ##STR2## where R is hydrogen or alkyl having from 1 to 6 carbon atoms.

Claim 11

The process of claim 8 where the carboxylic acid is propionic acid.

Claim 12

The process of claim 5 where the carboxylic acid is present in an amount of from 0.1 to 2.5 moles per liter of solution.

Claim 13

The process of claim 6 where the contact of the copper metal is by immersion of the copper metal in a solution of the etchant.

Claim 14

The process of claim 6 where the contact of the copper metal is by spraying the etchant onto the surface of the copper metal.

Claim 15

A process for the manufacture of a printed circuit board comprising the step of contacting a copper clad printed circuit board base material, having an etch resist over the surface of the copper defining a circuit pattern, with an etchant for a time sufficient to remove all exposed copper, said etchant comprising an aqueous solution of a peroxide and sulfuric acid, each in an amount sufficient to provide a sustained rate of etching, and a low molecular weight carboxylic acid in an amount sufficient to exalt the etch rate to a rate in excess of that achievable by the peroxide-sulfuric mixture alone.

Claim 16

A process for the manufacture of a printed circuit board comprising the step of contacting a copper clad printed circuit board base material, having an etch resist over the surface of the copper defining a circuit pattern, with an etchant for a time sufficient to remove all exposed copper, said etchant comprising an aqueous solution of a peroxide and sulfuric acid, each in an amount sufficient to provide a sustained rate of etching, and a low molecular weight carboxylic acid in an amount sufficient to exalt the etch rate to a rate in excess of that achievable by the peroxide-sulfuric mixture alone.

Claim 17

The process of claim 13 where the carboxylic acid is present in an amount sufficient to double the etch rate relative to said etchant free of the carboxylic acid.

Claim 18

The process of claim 13 where the peroxide content varies between about 0.5 and 2.5 moles per liter.

Claim 19

The process of claim 15 where the carboxylic acid conforms to the general formula: ##STR3## where R is hydrogen or alkyl having from 1 to 6 carbon atoms.

Claim 20

The process of claim 16 where the carboxylic acid is propionic acid.

Claim 21

The process of claim 13 where the concentration of the carboxylic acid ranges from about 0.1 to 2.5 moles per liter of solution.

Claim 22

The process of claim 13 where the etch resist is solder or immersion tin.

Claim 23

The process of claim 19 where the etchant contains a solution soluble phosphate.

Claim 24

The process of claim 13 where the contact of the printed circuit board base material is by immersion in a solution of the etchant.

Claim 25

The process of claim 13 where the contact of the circuit board base material is by spraying the etchant onto the surface of the printed circuit board base material.

Claim 26

A process for exalting the etch rate of a hydrogen peroxide-sulfuric acid etchant, said process comprising adding a low molecular weight carboxylic acid to the etchant in a concentration sufficient to double the etch rate compared to an etchant free of the carboxylic acid.

Claim 27

A process for exalting the etch rate of a hydrogen peroxide-sulfuric acid etchant, said process comprising adding a low molecular weight carboxylic acid to the etchant in a concentration sufficient to double the etch rate compared to an etchant free of the carboxylic acid.

Claim 28

The process of claim 23 where the peroxide content varies between 0.5 and 2.5 moles per liter.

Claim 29

The process of claim 23 where the carboxylic acid conforms to the general formula ##STR4## where R is hydrogen or alkyl having from 1 to 6 carbon atoms.

Claim 30

The process of claim 25 where the carboxylic acid is propionic acid.

Claim 31

The process of claim 26 where the carboxylic acid is present in an amount of from 0.1 to 2.5 moles per liter of solution.