Semiconductor device and method for manufacturing the same
In one embodiment, a preliminary solder layer made of a Sn alloy is formed on a connecting pad of a wiring substrate. A solder bump made of a Sn alloy is formed on an electrode pad of a semiconductor chip. After contacting the preliminary solder layer and the solder bump, the preliminary solder layer and the solder bump are melted by heating to a temperature of their melting points or higher to form a solder connecting part made of a Sn alloy containing Ag and Cu. Only the preliminary solder layer of the preliminary solder layer and the solder bump is composed of a Sn alloy containing Ag.
1. A method for manufacturing a semiconductor device, comprising:
forming a preliminary solder layer made of a first Sn alloy containing Ag on a connecting pad of a wiring substrate;
forming a solder bump made of a second Sn alloy not containing Ag on an electrode pad of a semiconductor chip;
contacting the preliminary solder layer and the solder bump while aligning; and
melting the preliminary solder layer and the solder bump by heating to a temperature equal to or higher than melting points thereof to form a solder connecting part made of a third Sn alloy containing Ag and Cu and connect the connecting pad of the wiring substrate and the electrode pad of the semiconductor chip.
2. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the preliminary solder layer is composed of a Sn—Ag alloy or a Sn—Ag—Cu alloy, and the solder bump is composed of a Sn—Cu alloy.
3. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the preliminary solder layer is composed of the first Sn alloy consisting essentially of one of Ag in a range from 0.4 to 6 mass % and the balance of Sn, or Ag in a range from 0.4 to 6 mass %, Cu in a range from 0.4 to 6 mass % and the balance of Sn.
4. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the solder bump is composed of the second Sn alloy consisting essentially of Cu in a range from 0.5 to 1 mass % and the balance of Sn.
5. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the solder connecting part is composed of the third Sn alloy consisting essentially of Ag in a range from 0.2 to 1.5 mass %, Cu in a range from 0.3 to 1 mass % and the balance of Sn.
6. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the solder bump is formed by stacked plating.
7. The method for manufacturing a semiconductor device according to claim 2 ,
wherein the solder bump is formed by stacking of Sn plating and Cu plating on the electrode pad.
8. The method for manufacturing a semiconductor device according to claim 2 ,
wherein the solder bump is formed by mounting a Sn—Cu alloy ball on the electrode pad.
9. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the solder bump is formed on the electrode pad via a barrier metal layer.
10. A method for manufacturing a semiconductor device, comprising:
forming a preliminary solder layer made of a first Sn alloy containing Ag on a connecting pad of a wiring substrate via a first barrier metal layer;
forming a solder bump made of a second Sn alloy not containing Ag on an electrode pad of a semiconductor chip via a second barrier metal layer;
contacting the preliminary solder layer and the solder bump while aligning; and
melting the preliminary solder layer and the solder bump by heating to a temperature equal to or higher than melting points thereof to form a solder connecting part made of a third Sn alloy containing Ag and Cu and connect the connecting pad of the wiring substrate and the electrode pad of the semiconductor chip.
11. The method for manufacturing a semiconductor device according to claim 10 ,
wherein the preliminary solder layer is composed of a Sn—Ag alloy or a Sn—Ag—Cu alloy, and the solder bump is composed of a Sn—Cu alloy.
12. The method for manufacturing a semiconductor device according to claim 10 ,
wherein the preliminary solder layer is composed of the first Sn alloy consisting essentially of one of Ag in a range from 0.4 to 6 mass % and the balance of Sn, or Ag in a range from 0.4 to 6 mass %, Cu in a range from 0.5 to 1 mass % and the balance of Sn.
13. The method for manufacturing a semiconductor device according to claim 10 ,
wherein the solder bump is composed of the second Sn alloy consisting essentially of Cu in a range from 0.5 to 1 mass % and the balance of Sn.
14. The method for manufacturing a semiconductor device according to claim 10 ,
wherein at least one of the first barrier metal layer or the second barrier metal layer has a Ni film, and
wherein the solder connecting part is composed of the third Sn alloy consisting essentially of Ag in a range not less than 0.2 mass % and less than 1 mass %, Cu in a range from 0.3 to 1 mass % and the balance of Sn.
15. The method for manufacturing a semiconductor device according to claim 10 ,
wherein the first barrier metal layer has a Ni film and a Pd film disposed on a side closer to the preliminary solder layer than the Ni film, and
wherein the solder connecting part is composed of the third Sn alloy consisting essentially of Ag in a range from 0.2 to 1.5 mass %, Cu in a range from 0.3 to 1 mass % and the balance of Sn.
16. The method for manufacturing a semiconductor device according to claim 10 ,
wherein the second barrier metal layer has a Ni film and a Pd film disposed on a side closer to the solder bump than the Ni film, and
wherein the solder connecting part is composed of the third Sn alloy consisting essentially of Ag in a range from 0.2 to 1.5 mass %, Cu in a range from 0.3 to 1 mass % and the balance of Sn.
17. The method for manufacturing a semiconductor device according to claim 11 ,
wherein the solder bump is formed by stacking of Sn plating and Cu plating or by mounting a Sn—Cu alloy ball.