Solder interconnect by addition of copper
A method of forming an electronic device provides an electronic device substrate having a solder bump pad located thereover. A nickel-containing layer is located over the solder bump pad. A copper-containing layer is formed on the nickel-containing layer prior to subjecting the electronic device to a reflow process.
1. A method of forming an electronic device, comprising:
providing an electronic device substrate having a solder bump located thereover;
forming a copper-containing layer on said solder bump; and
placing said copper-containing layer in contact with a nickel-containing layer while causing said solder bump to melt.
2. The method of claim 1 , wherein said electronic device substrate is an integrated circuit substrate.
3. The method of claim 1 , wherein said electronic device substrate is an electronic device package substrate.
4. The method of claim 1 , wherein said copper-containing layer has a copper mass in a range of about 0.5% to about 4% of a mass of said solder bump.
5. The method of claim 1 , further comprising melting said solder bump, thereby forming a (Ni,Cu)/Sn intermetallic compound region between said solder bump and a solder bump pad.
6. A method of forming an electronic device, comprising:
providing an electronic device substrate having a solder bump located thereover; and
forming a copper-containing layer on said solder bump, wherein said copper-containing layer is formed by electroplating.
7. A method of forming an electronic device, comprising:
providing an electronic device substrate having a solder bump located thereover; and
forming a copper-containing layer on said solder bump, wherein said copper-containing layer is formed from a copper paste.
8. A method of forming an electronic device, comprising:
providing an electronic device substrate having a bump pad located thereover, said bump pad including side surfaces and a planar top surface comprising Al or Cu;
providing a nickel-containing layer located on and forming an interface with said top and side surfaces of said solder bump pad;
providing a solder bump located over said nickel-containing layer, wherein said solder bump is composed of an alloy of silver, tin and copper; and
forming an intermetallic compound layer located between and in contact with said nickel-containing layer and said solder bump, wherein said intermetallic compound layer includes:
a first intermetallic compound sublayer adjacent to said solder bump, said first intermetallic compound sublayer composed of an alloy of nickel, copper and tin, and
a second intermetallic compound sublayer adjacent to said first intermetallic compound sublayer and said nickel-containing layer, said second intermetallic compound sublayer composed of an alloy of nickel and tin.
9. The method of claim 8 , wherein said nickel-containing layer is an elemental nickel layer.
10. The method of claim 8 , wherein forming said intermetallic compound layer includes melting said a solder bump in contact with a copper-containing layer, wherein said intermetallic compound layer has a concentration of copper in a range of about 55 wt % to about 65 wt %.