Abstract: Electroless metal plating solutions are formulated and controlled to provide high quality metal deposits by establishing the intrinsic cathodic reaction rate of the solution less than 110% of the intrinsic anodic reaction rate. Methods are provided to formulate electroless copper plating solutions which can deposit copper on printed wiring boards of quality sufficient to pass a thermal stress of 10 seconds contact with molten solder at 288.degree. C. without cracking the copper deposits on the surface of the printed wiring boards or in the holes. The ratio of the anodic reaction rate to the cathodic reaction rate can be determined by electrochemical measurements, or it can be estimated by varying the concentration of the reactants and measuring the plating rates.

Abstract: Method for electroplating non-metallic surfaces on a substrate, e.g. of plating holes in metal clad laminates, is disclosed. Metallic sites are formed on the surface and the resulting site-containing surface is electroplated by means of an electroplating bath comprising a component which causes the plating to preferentially occur at said sites in comparison to the plating on surfaces of the same metal as the one plated out; whereby a rate differential of the plating-reaction on site-surfaces is achieved with respect to the plating-reaction on a surface consisting of the metal to be plated out.

Abstract: The metallic surfaces of plating equipment in use during electroless copper deposition, such as vessels, racks supporting substrates being plated, plumbing, and the like are rendered substantially resistant to electroless copper deposition for extended periods by initially imposing on such equipment surfaces an electrical potential more positive than the mixed potential of the electroless copper solution and sufficiently positive to resist electroless deposition, electrolessly depositing copper on the substrate being plated, and while depositing such copper maintaining on the equipment surface a potential sufficiently positive to resist the formation of adherent electroless copper deposits.

Abstract: Sensitizing solutions for rendering surfaces receptive to the deposition of adherent electroless metal comprising a precious metal and a stoichiometric excess of a Group IV metal which is capable of two valence states are stabilized against precious metal separation by adding a Lewis Base, e.g., hydroquinone or hydroxylamine. Processes for rendering surfaces receptive to the deposition of an electroless metal are also provided in which there are employed the stabilized sensitizing solutions.

Abstract: Methods are provided for separating by-products from alkanolamine complexing agents and heavy metals complexed with alkanolamines, and for the waste-treating of solutions containing such complexed heavy metals and complexing agents. Illustratively, the pH of an electroless metal deposition bath or bath effluent which contains an alkanolamine complexing agent and an alkanolamine-complexed heavy metal is adjusted to render the complexing agent and complexed heavy metal extractable by an ion exchange medium, the pH-adjusted bath liquid is contacted with an ion-exchange medium capable of extracting the complexed heavy metal and complexing agent, the contacted bath liquid, which contains by-products and is substantially free of the complexed heavy metal and the complexing agent is removed from the ion exchange medium and the complexed heavy metal and complexing agent are recovered from the exchange medium for further use in electroless metal deposition baths.

Abstract: Sensitizing solutions for rendering surfaces receptive to the deposition of adherent electroless metal comprising a precious metal and a stoichiometric excess of a Group IV metal which is capable of two valence states are stabilized against precious metal separation by adding a Lewis Base, e.g., hydroquinone or hydroxylamine. Processes for rendering surfaces receptive to the deposition of an electroless metal are also provided in which there are employed the stabilized sensitizing solutions.

Abstract: There are provided stable, non-colloidal solutions for sensitizing a surface to the deposition of adherent electroless metal, the solutions comprising a liquid medium and dissolved therein an effective, sensitizing amount of a reaction product of the general formula:A .sup.. D .sup.. E .sup.. Gwherein A is an ion of a precious metal selected from those of the fifth and sixth periods of Groups VIII and IB of the Periodic Table of elements; D is a group IV metal of the Periodic Table of Elements which is capable of two valence states; E is an anion capable of forming a stable complex with components A and D; and G is a hydroxyl group-containing aromatic organic compound capable of forming a stable complex with component A, or component D.

Abstract: Sensitizing solutions for rendering surfaces receptive to the deposition of adherent electroless metal comprising a precious metal and a stoichiometric excess of a Group IV metal which is capable of two valence states are stabilized against precious metal separation by adding a Lewis Base, e.g., hydroquinone or hydroxylamine. Processes for rendering surfaces receptive to the deposition of an electroless metal are also provided in which there are employed the stabilized sensitizing solutions.

Abstract: Electroless metal deposition solutions are provided which comprise, in combination, an ion of a metal whose electroless metal deposition is desired; a complexing agent for said ion; a reducing agent for said ion; a pH regulator; and less than about 25 parts per million of metal ions which have an oxidation potential greater than the oxidation potential of the ion of the metal whose electroless deposition is desired.