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US 2016/0105975 A1Published application
Filling through-holes
AssigneeRohm and Haas Electronic Materials LLC
InventorsNagarajan Jayaraju, Leon R. Barstad, Elie H. Najjar
Life of this patent
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Abstract
Pulse plating methods which include a forward pulse but no reverse pulse inhibit or reduce dimpling and voids during copper electroplating of through-holes in substrates such as printed circuit boards. The pulse plating methods may be used to fill through-holes with copper where the through-holes are coated with electroless copper or flash copper.
Claims10
A method comprising:
- a) providing a substrate with a plurality of through-holes comprising a layer of electroless copper, copper flash or combinations thereof on a surface of the substrate and walls of the plurality of through-holes;
- b) immersing the substrate in a copper electroplating bath comprising an anode;
- and
- c) filling the through-holes with copper by a pulse plating cycle consisting of applying a forward current density for a predetermined period of time followed by interrupting the forward current density for a predetermined period of time and applying a second forward current density for a predetermined period of time and interrupting the second forward current density for a predetermined period of time and optionally repeating the cycle.
1 more element
Dependencies are inferred from the claim text.