Capping copper bumps
View Patent ↗A structure including a substrate, a copper bump formed over the substrate, and a barrier layer comprising an alloy of at least one of iron and nickel, formed over the copper bump, and methods to make such a structure.
1. A structure comprising:
a substrate;
a copper bump formed over the substrate;
and a barrier layer comprising an alloy of at least one of iron and nickel,
formed over the copper bump;
a pre-tin solder layer over the barrier layer, the pre-tin solder layer including an alloy comprising at least one of tin, indium, silver, gold, and palladium; and
a solder bump soldered to the pre-tin solder layer.
2. The structure of claim 1 further comprising a solder bump soldered to the barrier layer formed over the copper bump.
3. A package comprising:
a die comprising a substrate and a copper bump formed over the substrate;
a barrier layer comprising an alloy of at least one of iron and nickel, the barrier layer being formed over the copper bump;
a pre-tin solder layer over the barrier layer; and
a package carrier comprising a solder bump coupled to the die.
4. The package of claim 3 wherein the pre-tin solder layer comprises an alloy, the alloy further comprising at least one of tin, indium, silver, gold, and palladium.
5. The package of claim 4 wherein the solder bump is coupled to the die by a reflowed solder connection formed between the solder bump and the pre-tin solder layer formed over the copper bump.
6. The package of claim 3 wherein the solder bump is coupled to the die by a reflowed solder connection formed between the solder bump and the barrier layer formed over the copper bump.