Loading patent…
AssigneeAtotech Deutschland GmbH
InventorsCarl Hutchinson, Hartmut Mahlkow, Christian Sparing
Estimating the term…
Known methods of improving the solderability of copper surfaces on printed circuit boards present the disadvantage that outer layers of an irregular thickness are formed at the metal surfaces, that these layers are very expensive or that the constituents used in manufacturing them are harmful to the environment. Furthermore, the metal surfaces are to be suited to form bond connections as well as electrical contacts. To overcome these problems there are disclosed a bath and a method of electroless plating of silver by way of charge exchange reaction on surfaces of metals that are less noble than silver, more particularly on copper, that contain at least one silver halide complex and not containing any reducing agent for Ag+ ions.
A bath for electroless plating of silver onto metal surfaces being less noble than silver by way of charge exchange reaction, the bath containing at least one silver halide complex and not containing any reducing agent for Ag+ ions.
The bath according to any of the previous claims, wherein the pH of the bath is adjusted to a value in the range of from 0 to 6.
The bath according to any of the previous claims, wherein the bath does not contain any anion selected from the group, comprising nitrate, sulfite, thiosulfate and derivatives of these anions.
The bath according to any of the previous claims, wherein the bath additionally contains at least one copper inhibitor.
The bath according to any of the previous claims, wherein the bath additionally contains at least one complexing agent for Cu2+ ions.
The bath according to any of the previous claims, wherein the bath additionally contains at least one surface-active agent.
A method of electroless plating of silver onto metal surfaces by way of charge exchange reaction the metal of the metal surfaces being less noble than silver, the method comprising the following method steps:
Dependencies are inferred from the claim text.