Stacked solder balls for integrated circuit device packaging and assembly
A semiconductor device is provided that includes a semiconductor chip, a plurality of solder bumps that electrically couple the semiconductor chip to the outside, and a metal bump being provided on the surface of each first solder bump which is at least a part of the plurality of solder bumps and being made of a metal having a melting point higher than that of the first solder bump. The wettability of the first solder bump is improved as each metal bump serves as a core when the corresponding first solder bump melts. Thus, the connection reliability of the first solder bump can be improved.
1. A semiconductor device comprising:
a semiconductor chip;
a plurality of solder bumps that electrically couple the semiconductor chip to an external circuit; and
a metal bump disposed on a surface of a first solder bump of the plurality of solder bumps wherein a width of the metal bump is less than the diameter of the first solder bump and comprising a metal having a melting point higher than that of the first solder bump wherein the first solder bump is positioned between the semiconductor chip and the metal bump.
2. The semiconductor device according to claim 1 , wherein the plurality of solder bumps include a second solder bump that has no metal bump on a surface thereof.
3. The semiconductor device according to claim 1 , wherein the metal bump is stacked on the surface of at least a part of the first solder bump.
4. The semiconductor device according to claim 1 , wherein the metal bump is stacked on a surface of a third solder bump.
5. The semiconductor device according to claim 1 , wherein the metal bump comprises a gold stud bump.
6. A method for manufacturing a semiconductor device, comprising the steps of:
forming a metal bump on a surface of a first solder bump of a plurality of solder bumps that electrically couple a semiconductor chip to an external electrode wherein the metal bump has a width that is less than the diameter of the first solder bump, the metal bump being made of a metal having a melting point higher than that of the first solder bump; and
bonding the first solder bump on a mounting portion wherein the first solder bump is positioned between the semiconductor chip and the metal bump.
7. The method for manufacturing a semiconductor device according to claim 6 , wherein the step of forming the metal bump on the surface of each first solder bump includes the step of: stacking a metal bump on a surface of a third solder bump on a surface of a fourth solder bump so that metal bumps, the number of which corresponds to surface irregularities of the mounting portion on which the solder bumps are mounted, are formed on the surfaces of the third solder bump and the fourth solder bump.
8. The method for manufacturing a semiconductor device according to claim 6 , wherein the step of forming a metal bump on the surface of each first solder bump includes forming, on the surface of each first solder bump, bumps having different heights corresponding to surface irregularities of the mounting portion on which the solder bumps are mounted.
9. A method for manufacturing a semiconductor device, the method comprising the steps of:
applying, to a surface of a solder bump that electrically couples a semiconductor chip to an external electrode, a flux containing a metal with a higher melting point than that of the solder bump wherein the width of the flux is less than the diameter of the solder bump; and
bonding the solder bump having the surface to which the flux is applied on a mounting portion wherein the solder bump is positioned between the semiconductor chip and the metal.
10. The method for manufacturing a semiconductor device according to any one of claims 6 to 9 , wherein the mounting portion is an interposer on which the semiconductor chip is mounted.