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US 9,754,909 B2Granted
Copper structures with intermetallic coating for integrated circuit chips
AssigneeMonolithic Power Systems, Inc.
InventorHunt Hang Jiang
Life of this patent
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Abstract
An integrated circuit (IC) chip includes a copper structure with an intermetallic coating on the surface. The IC chip includes a substrate with an integrated circuit. A metal pad electrically connects to the integrated circuit. The copper structure electrically connects to the metal pad. A solder bump is disposed on the copper structure. The surface of the copper structure has a coating of intermetallic. The copper structure can be a redistribution layer and a copper pillar that is disposed on the redistribution layer.
Claims8
A method of manufacturing an integrated circuit (IC) chip, the method comprising:
- forming a copper seed layer over a substrate, the copper seed layer being formed to electrically connect to a metal pad that electrically connects to an integrated circuit in the substrate;
- electroplating a first copper layer on the copper seed layer;
- electroplating a second copper layer on the first copper layer;
- electroplating solder on the second copper layer;
- electroless plating a coating of tin on a surface of the first copper layer, the second copper layer, and the solder;
- and
- heating the coating of tin to form a tin-copper intermetallic coating on the surface of the first copper layer and the second copper layer.
4 more elements
Dependencies are inferred from the claim text.