Palladium plating prodedure

Claim 2

A process for electroplating a metallic substance on a surface, said metallic substance consists essentially of at least 10 mole percent palladium, remainder selected from the group consisting of silver, copper and nickel, comprising the step of passing current through a cathode, an electroplating bath and an anode with a cathode potential great enough to electroplate palladium, said electrochemical bath having a conductivity greater than a 10 -3 mho-cm and a pH between 7.5 and 13.5, characterized in that the electroplating bath comprises an aqueous solution of palladium-aliphatic polyamine complex in which the aliphatic polyamine is selected from the group consisting of diaminopropane (including 1,3-diaminopropane), 1,4-diaminobutane, 1,6-diaminohexane, N,N,N',N'-tetramethyl-ethylenediamine and 2-hydroxy-1,3-diaminopropane.

Claim 3

The process of claim 1 in which the metallic substance consists essentially of palladium.

Claim 4

The process of claim 1 in which the aliphatic polyamine is 1,3-diaminopropane.

Claim 5

The process of claim 1 in which the pH varies from 11.0 to 12.5.

Claim 6

The process of claim 1 in which the electroplating bath comprises a buffer.

Claim 7

The process of claim 5 in which the buffer comprises hydrogen phosphate ion and phosphate ion.

Claim 8

The process of claim 6 in which the buffer concentration varies from 0.1 to 2 Molar and the ratio of hydrogen phosphate to phosphate ion is from 5/1 to 1/5.

Claim 9

The process of claim 1 in which the electroplating process is carried out at a temperature between room temperature and 80 degrees C.

Claim 10

The process of claim 8 in which the temperature is between 40 and 60 degrees C.

Claim 11

The process of claim 1 in which the palladium concentration is from 0.01 Molar to saturation.

Claim 12

The process of claim 10 in which the palladium is from 0.05 to 1.0 Molar.

Claim 13

The process of claim 1 in which the molar concentration of aliphatic polyamine is from 0.5 times the molar concentration of palladium to saturation of the aliphatic polyamine.

Claim 14

The process of claim 12 in which the concentration of aliphatic polyamine is from two to 12 times the mole concentration of palladium.

Claim 15

The process of claim 1 in which the plating current density is between 50 and 1000 ASF.

Claim 16

The process of claim 1 in which the palladium in the electroplating bath is replenished by the addition of a source of palladium.

Claim 17

The process of claim 15 in which the source of palladium is palladium chloride.

Claim 18

The process of claim 15 in which the source of palladium is a source of tetrachloropalladate ion.

Claim 19

The process of claim 1 in which the plating current density is up to 50 ASF.

Claim 20

A process for electroplating a metallic substance on a surface, said metallic substance consisting essentially of at least 10 mole percent palladium remainder selected from the group consisting of silver, copper and nickel, comprising the step of passing current through a cathode, an electroplating bath and an anode with a cathode potential great enough to electroplate palladium, said electrochemical bath having a conductivity greater than 10 -3 mho-cm and a pH between 7.5 and 13.5, characterized in that the electrochemical bath comprises an aqueous solution of palladium-aliphatic polyamine complex, said complex the same as results from reacting a source of palladium with at least one aliphatic polyamine selected from the group consisting of diaminopropane (including 1,3-diaminopropane), 1,4-diaminobutane, 1,6-diaminohexane, N,N,N',N'-tetramethylethylene diamine and 2-hydroxy-1,3-diaminopropane.

Claim 21

A process for electroplating a metallic substance on a surface, said metallic substance consisting essentially of at least 10 mole percent palladium remainder selected from the group consisting of silver, copper and nickel, comprising the step of passing current through a cathode, an electroplating bath and an anode with a cathode potential great enough to electroplate palladium, said electrochemical bath having a conductivity greater than 10 -3 mho-cm and a pH between 7.5 and 13.5, characterized in that the electrochemical bath comprises an aqueous solution of palladium-aliphatic polyamine complex, said complex the same as results from reacting a source of palladium with at least one aliphatic polyamine selected from the group consisting of diaminopropane (including 1,3-diaminopropane), 1,4-diaminobutane, 1,6-diaminohexane, N,N,N',N'-tetramethylethylene diamine and 2-hydroxy-1,3-diaminopropane.

Claim 22

The process of claim 19 in which the source of palladium is palladium chloride.

Claim 23

The process of claim 19 in which the aliphatic polyamine is 1,3-diaminopropane.

Claim 24

The process of claim 19 in which the metallic substance consists essentially of palladium.

Claim 25

A process for electroplating a metallic substance on a surface, said metallic substance consists essentially of at least 10 mole percent palladium, remainder selected from the group consisting of silver, copper and nickel, comprising the step of passing current through a cathode, an electroplating bath and an anode with a cathode potential great enough to electroplate palladium, said electrochemical bath having a conductivity greater than 10 -3 mho-cm and a pH between 7.5 and 13.5, characterized in that the electroplating bath comprises an aqueous solution of palladium-aliphatic polyamine complex in which the aliphatic polyamine is diethylenetriamine and the molar concentration of diethylenetriamine is from 0.5 times the molar concentration of palladium to saturation of the diethylenetriamine.

Claim 26

A process for electroplating a metallic substance on a surface, said metallic substance consists essentially of at least 10 mole percent palladium, remainder selected from the group consisting of silver, copper and nickel, comprising the step of passing current through a cathode, an electroplating bath and an anode with a cathode potential great enough to electroplate palladium, said electrochemical bath having a conductivity greater than 10 -3 mho-cm and a pH between 7.5 and 13.5, characterized in that the electroplating bath comprises an aqueous solution of palladium-aliphatic polyamine complex in which the aliphatic polyamine is diethylenetriamine and the molar concentration of diethylenetriamine is from 0.5 times the molar concentration of palladium to saturation of the diethylenetriamine.

Claim 27

A process for electroplating a metallic substance consisting essentially of at least 10 mole percent palladium remainder selected from the group consisting of silver, copper and nickel, comprising the step of passing current through a cathode, an electroplating bath and an anode with a cathode potential great enough to electroplate palladium, said electrochemical bath having a conductivity greater than 10 -3 mho-cm and a pH between 7.5 and 13.5, characterized in that the electrochemical bath comprises an aqueous solution of palladium-aliphatic polyamine complex, said complex the same as results from reacting a source of palladium with diethylenetriamine and the molar concentration of diethylenetriamine is from 0.5 times the molar concentration of palladium to saturation of diethylenetriamine.

Claim 28

A process for electroplating a metallic substance consisting essentially of at least 10 mole percent palladium remainder selected from the group consisting of silver, copper and nickel, comprising the step of passing current through a cathode, an electroplating bath and an anode with a cathode potential great enough to electroplate palladium, said electrochemical bath having a conductivity greater than 10 -3 mho-cm and a pH between 7.5 and 13.5, characterized in that the electrochemical bath comprises an aqueous solution of palladium-aliphatic polyamine complex, said complex the same as results from reacting a source of palladium with diethylenetriamine and the molar concentration of diethylenetriamine is from 0.5 times the molar concentration of palladium to saturation of diethylenetriamine.