Silver plating in electronics manufacture
AssigneeEnthone Inc.
InventorsYung-Herng Yau, Thomas Richardson, Joseph Abys, Karl Wengenroth, Anthony Fiore, Chen Xu, Chonglun Fan, John Fudala
Life of this patent
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Abstract
Compositions and methods for silver plating onto metal surfaces such as PWBs in electronics manufacture to produce a silver plating which is greater than 80 atomic % silver, tarnish resistant, and has good solderability.
Claims109
A process for Ag plating a metal surface comprising:
- contacting the metal surface with a composition comprising a source of Ag ions and water;
- and
- forming by immersion displacement a Ag-based coating on the metal surface, wherein the ionic content of the composition is such that it has a room temperature conductivity below about 25 mS/cm.
A plating composition for Ag plating a metal surface, the composition comprising a source of Ag ions and water and having an ionic content such that the composition has a room temperature conductivity below about 25 mS/cm.
A process for Ag plating a metal surface comprising:
- contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) an alkylene polyamine polyacetic acid compound;
- and
- c) water;
- wherein the composition has a pH between 1 and about 3 and
- forming by immersion displacement a Ag-based coating on the metal surface.
A composition for Ag plating a metal surface comprising:
- a) a source of Ag ions;
- b) an alkylene polyamine polyacetic acid compound;
- and
- c) water;
- wherein the composition has a pH between 1 and about 3.
A process for Ag plating a metal surface comprising contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) an amino acid inhibitor of Ag deposition which functions at a pH between about 4 and about 5 to slow Ag deposition rate;
- and
- c) water;
- to form a Ag-based coating on the metal surface by displacement plating under plating conditions where metal of the metal surface functions as a reducing agent for the Ag ions.
A composition for Ag plating a metal surface comprising:
- a) a source of Ag ions;
- b) an amino acid inhibitor of Ag deposition which functions at a pH between about 4 and about 5 to slow Ag deposition rate;
- and
- c) water.
A process for Ag plating a metal surface comprising:
- contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) an amino acid selected from the group consisting of chiral isomers of and racemic mixtures of alanine;
- and
- c) water;
- and
- forming by immersion displacement a Ag-based coating on the metal surface.
80-81. (canceled)
A process for Ag plating a metal surface comprising:
- contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) a hydantoin derivative;
- c) an amino acid additive;
- and
- d) water;
- and
- forming by immersion displacement a Ag-based coating on the metal surface.
A composition for Ag plating a metal surface comprising contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) a hydantoin derivative;
- and
- c) water.
A process for Ag plating a metal surface comprising:
- contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) an ethylene oxide/propylene oxide block co-polymer additive;
- and
- c) water;
- and
- forming by immersion displacement a Ag-based coating on the metal surface.
A process for Ag plating a metal surface comprising:
- contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) an alkaline earth/alkali metal-free source of alkylene polyamine polyacetic acid compound;
- and
- c) water;
- wherein the composition is free of added alkaline earth metal ions and alkali metal ions;
- and
- forming by immersion displacement a Ag-based coating on the metal surface.
A composition for Ag plating a metal surface comprising contacting the metal surface with a composition comprising:
- a) a source of Ag ions;
- b) an alkaline earth/alkali metal-free source of alkylene polyamine polyacetic acid compound;
- and
- c) water.
A process for Ag plating a Cu surface of a printed wiring board substrate having electrical interconnect recesses comprising sequentially a) applying a Ag immersion displacement plating composition comprising a source of Ag ions to the Cu surface, and b) mechanically assisting the Ag plating composition into the electrical interconnect recesses, thereby forming by immersion displacement a Ag-based coating on the Cu surface.
A process for Ag plating a Cu surface of a printed wiring board substrate comprising:
- contacting the Cu surface with a composition comprising:
- a) a source of Ag ions;
- b) HEDTA;
- c) an ethylene oxide/propylene oxide block co-polymer additive;
- d) a tarnish inhibitor;
- and
- e) water;
- wherein the composition has pH between 1 and about 3, and a room temperature conductivity of less than about 25 mS/cm,;
- and
- forming by immersion displacement a Ag-based coating on the metal surface which comprises at least about 90 atomic % Ag (bulk average).
A composition for Ag plating a Cu surface of a printed wiring board substrate, the composition comprising:
- a) a source of Ag ions;
- b) HEDTA;
- c) an ethylene oxide/propylene oxide block co-polymer additive;
- d) a tarnish inhibitor;
- and
- e) water;
- wherein the composition has pH between 1 and about 3, and a room temperature conductivity of less than about 25 mS/cm.
A process for Ag plating a Cu surface of a printed wiring board substrate comprising:
- contacting the Cu surface with a composition comprising:
- a) a source of Ag ions;
- b) an amino acid additive selected from the group consisting of chiral isomers of and racemic mixtures of alanine;
- c) an ethylene oxide/propylene oxide block co-polymer additive;
- d) a hydantoin derivative;
- and
- e) water;
- wherein the composition has pH between about 4 and about 5, and a room temperature conductivity of less than about 25 mS/cm,;
- and
- forming by immersion displacement a Ag-based coating on the metal surface which comprises at least about 90 atomic % Ag (bulk average).
A composition for Ag plating a Cu surface of a printed wiring board substrate, the composition comprising:
- a) a source of Ag ions;
- b) an amino acid additive selected from the group consisting of chiral isomers of and racemic mixtures of alanine;
- c) an ethylene oxide/propylene oxide block co-polymer additive;
- d) a hydantoin derivative;
- and
- e) water;
- wherein the composition has pH between about 4 and about 5, and a room temperature conductivity of less than about 25 mS/cm.
109-111. (canceled)
Dependencies are inferred from the claim text.