High-strength solder joint
View Patent ↗A soldering method achieving a high-strength joint between a solder and an nickel/gold electroless plated surface is disclosed. The nickel/gold electroless plated layer is soldered using a solder including tin (Sn), silver (Ag), and copper (Cu). At a solder joint, a layer sturcture of nickel layer/intermetallic compound layer/solder layer is formed. The intermetallic compound layer is composed mainly of tin (Sn) and copper (Cu), and further including nickel (Ni). The intermetallic compound layer has cauliflower-shaped surfaces formed in a solder-layer's side thereof.
1. A solder joint between a solder and a conductor terminal formed on a wiring structure, comprising:
a nickel layer formed by nickel-phosphorus electroless plating on the conductor terminal;
an intermetallic compound layer formed on the nickel layer, the intermetallic compound layer including tin (Sn), copper (Cu),and nickel (Ni); and
a solder layer formed on the intermetallic compound layer, the solder layer including tin (Sn), silver (Ag), and copper (Cu).
2. The solder joint according to claim 1 , wherein the intermetallic compound is composed mainly of tin (Sn) and copper (Cu).
3. The solder joint according to claim 1 , wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof.
4. The solder joint according to claim 1 , wherein the conductor terminal is composed mainly of copper.
5. A solder joint between a solder and a conductor terminal formed on a wiring structure, comprising:
a nickel layer formed by nickel-phosphorus electroless plating on the conductor terminal;
an intermetallic compound layer formed on the nickel layer; and
a solder layer formed on the intermetallic compound layer,
wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof, the botryoidal surfaces comprising tin, copper, and nickel.
6. The solder joint according to claim 5 , wherein the conductor terminal is composed mainly of copper.
7. The solder joint of claim 5 , wherein, the solder layer includes tin (Sn), silver (Ag), and copper (Cu).
8. A wiring structure having a plurality of conductor terminals formed thereon, each of which is soldered to form a solder joint, the solder joint comprising:
a nickel layer formed by nickel-phosphorus electroless plating on a said conductor terminal;
an intermetallic compound layer formed on the nickel layer, the intermetallic compound layer including tin (Sn), copper (Cu),and nickel (Ni); and
a solder layer formed on the intermetallic compound layer, the solder layer including tin (Sn), silver (Ag), and copper (Cu).
9. The wiring structure according to claim 8 , wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof.
10. A wiring structure having a plurality of conductor terminals formed thereon, each of which is soldered to form a solder joint, the solder joint comprising:
a nickel layer formed by nickel-phosphorus electroless plating on a said conductor terminal;
an intermetallic compound layer formed on the nickel layer; and
a solder layer formed on the intermetallic compound layer,
wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof, the botryoidal surfaces comprising tin, copper, and nickel.
11. The wiring structure of claim 10 , wherein, the solder layer includes tin (Sn), silver (Ag), and copper (Cu).
12. A device comprising:
a wiring substrate having a plurality of substrate terminals formed thereon; and
a functional circuit having a plurality of circuit terminals, wherein the substrate terminals are soldered to respective ones of the circuit terminals at solder joints,
wherein each of the solder joints comprises:
a nickel layer formed by nickel-phosphorus electroless plating on each of a corresponding substrate terminal and a corresponding circuit terminal;
an intermetallic compound layer formed on the nickel layer, the intermetallic compound layer including tin (Sn), copper (Cu),and nickel (Ni); and
a solder layer formed on the intermetallic compound layer, the solder layer including tin (Sn), silver (Ag), and copper (Cu).
13. The device according to claim 12 , wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof.
14. A device comprising:
a wiring substrate having a plurality of substrate terminals formed thereon; and
a functional circuit having a plurality of circuit terminals, wherein the substrate terminals are electrically connected to respective ones of the circuit terminals at solder joints,
wherein each of the solder joints comprises:
a nickel layer formed by nickel-phosphorus electroless plating on each of a corresponding substrate terminal and a corresponding circuit terminal;
an intermetallic compound layer formed on the nickel layer; and
a solder layer formed on the intermetallic compound layer,
wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof, the botryoidal surfaces comprising tin, copper, and nickel.
15. The device of claim 14 , wherein, the solder layer includes tin (Sn), silver (Ag), and copper (Cu).
16. A device comprising:
a printed circuit substrate having a plurality of substrate terminals formed thereon; and
a semiconductor chip package having a plurality of package terminals, wherein the substrate terminals are soldered to respective ones of the package terminals at solder joints,
wherein each of the solder joints comprises:
a nickel layer formed by nickel-phosphorus electroless plating on each of a corresponding substrate terminal and a corresponding package terminal;
an intermetallic compound layer formed on the nickel layer, the intermetallic compound layer including tin (Sn), copper (Cu), and nickel (Ni); and
a solder layer formed on the intermetallic compound layer, the solder layer including tin (Sn), silver (Ag), and copper (Cu).
17. The device according to claim 16 , wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof.
18. A device comprising:
a printed circuit substrate having a plurality of substrate terminals formed thereon; and
a semiconductor chip package having a plurality of package terminals, wherein the substrate terminals are soldered to respective ones of the package terminals at solder joints,
wherein each of the solder joints comprises:
a nickel layer formed by nickel-phosphorus electroless plating on each of a corresponding substrate terminal and a corresponding package terminal;
an intermetallic compound layer formed on the nickel layer; and
a solder layer formed on the intermetallic compound layer,
wherein the intermetallic compound layer has botryoidal surfaces formed in a solder-layer's side thereof, the botryoidal surfaces comprising tin, copper, and nickel.
19. The device of claim 18 , wherein, the solder layer includes tin (Sn), silver (Ag), and copper (Cu).