Bumped chip package fabrication method and structure
View Patent ↗A method of fabricating a bumped chip package includes forming a first seed layer on a dielectric layer, the dielectric layer comprising a dielectric layer opening exposing a substrate terminal of a substrate, the first seed layer being formed within the dielectric layer opening and on the substrate terminal. A circuit pattern is plated on the first seed layer, wherein an exposed portion of the first seed layer is exposed from the circuit pattern. The exposed portion of the first seed layer is removed by laser-ablation. By using a laser-ablation process, a chemical etching process is avoided thus eliminating the need to treat or dispose of chemical etching hazardous waste. Further, circuit pattern width erosion and undercut of the circuit pattern associated with a chemical etching process are avoided.
1. A method of fabricating a bumped chip package comprising:
forming a first metal layer on a substrate;
plating a circuit pattern on the first metal layer, wherein an exposed portion of the first metal layer is exposed from the circuit pattern; and
removing the exposed portion of the first metal layer by laser-ablation.
2. The method of claim 1 wherein the first metal layer comprises copper.
3. The method of claim 1 wherein the forming a first metal layer comprises plating an electrically conductive material.
4. The method of claim 1 wherein the forming a first metal layer comprises sputtering an electrically conductive material.
5. The method of claim 1 wherein the first metal layer is used as a plating electrode during the plating a circuit pattern.
6. The method of claim 1 wherein the laser-ablation comprises directing a laser beam at the exposed portion and moving the laser beam.
7. The method of claim 6 wherein the exposed portion is completely removed by the laser beam.
8. The method of claim 1 further comprising forming a dielectric layer on the substrate, the dielectric layer comprising a dielectric layer opening exposing a substrate terminal of the substrate, the first metal layer being formed on the dielectric layer, within the dielectric layer opening, and on the substrate terminal.
9. The method of claim 1 wherein after the removing, a remaining circuit pattern portion of the first metal layer comprises perpendicular sidewalls.
10. The method of claim 1 wherein the removing comprises:
vaporizing the exposed portion of the first metal layer; and
recapturing and recycling the vaporized exposed portion.
11. A method of fabricating a bumped chip package comprising:
forming a metal layer on a substrate;
plating an Under Bump Metallization (UBM) pattern on the metal layer, wherein an exposed portion of the metal layer is exposed from the UBM pattern; and
removing the exposed portion of the metal layer by laser-ablation.
12. The method of claim 11 further comprising:
applying a resist to the metal layer;
patterning the resist to form a UBM pattern artifact therein, the UBM pattern artifact exposing a UBM pattern portion of the metal layer, wherein the plating the UBM pattern comprises plating the UBM pattern to completely fill the UBM pattern artifact using the metal layer as a plating electrode; and
stripping the resist.
13. The method of claim 12 further comprising applying a solder ball to the UBM pattern.
14. The method of claim 13 further comprising reflowing the solder ball to form an interconnection ball.
15. The method of claim 14 wherein the reflowing fuses the solder ball to the UBM pattern.
16. The method of claim 11 wherein after the removing, a remaining UBM pattern portion of the metal layer comprises perpendicular sidewalls.
17. The method of claim 11 further comprising forming a dielectric layer on the substrate, the dielectric layer comprising a dielectric layer opening exposing a substrate terminal of the substrate, the metal layer being formed on the dielectric layer, within the dielectric layer opening, and on the substrate terminal.
18. The method of claim 11 further comprising:
applying a resist to the metal layer;
patterning the resist to form a UBM pattern artifact therein, the UBM pattern artifact exposing a UBM pattern portion of the metal layer, wherein the plating the UBM pattern comprises plating the UBM pattern to partially fill the UBM pattern artifact using the metal layer as a plating electrode; and
filling the UBM pattern artifact with solder.
19. The method of claim 18 further comprising:
stripping the resist, wherein the removing is performed subsequent to the stripping; and
reflowing the solder to form an interconnection ball on the UBM pattern subsequent to the removing.
20. A method of fabricating a bumped chip package comprising:
forming a metal layer on a substrate;
forming a conductive bump on the metal layer, wherein an exposed portion of the metal layer is exposed from the bump; and
removing the exposed portion of the metal layer by laser-ablation.