Method for applying solder to redistribution lines

1. A method of making an electronic component, the method comprising:

forming an electrically conductive redistribution line on a surface of a semiconductor chip, the redistribution line including a solder pad;

forming a covering material over the solder pad;

passivating an uncovered portion of the redistribution line, the covering material preventing passivation of the solder pad; and

forming solder over the solder pad, the uncovered portion of the redistribution line having solder resist properties due to the passivating.

2. The method according to claim 1 , wherein forming an electrically conductive redistribution line comprises:

forming a conductive layer over the surface of the semiconductor chip;

forming a mask over the conductive layer, the mask including a mask opening corresponding to a pattern of the redistribution line; and

forming conductive material in the mask opening.

3. The method according to claim 2 , wherein the conductive layer comprises a seed layer and wherein the conductive material comprises copper.

4. The method according to claim 2 , wherein passivating the uncovered portion of the redistribution line comprises forming a solder resist layer over the uncovered portion of the redistribution lines, and wherein forming the solder comprises melting the solder onto the solder pad, the solder being restricted by the solder resist layer.

5. The method according to claim 2 , further comprising:

removing the covering material after passivating the uncovered portion of the redistribution line; and

removing portions of the conductive layer and the mask not beneath the redistribution line.

6. The method according to claim 5 , wherein the covering material is removed at the same time as the mask.

7. The method according to claim 1 , wherein the covering material has properties of a flux, the solder being formed over the covering material.

8. The method according to claim 7 , wherein forming solder over the solder pad comprises forming a solder ball into an opening that remains over the solder pad.

9. The method according to claim 1 , wherein passivating comprises forming a layer of material that acts as both a passivation layer and a solder resist layer.

10. The method according to claim 9 , wherein forming a layer of material comprises forming a nickel layer.

11. The method according to claim 9 , wherein forming a layer of material comprises forming a polymer layer.

12. The method according to claim 9 , wherein forming a layer of material comprises oxidizing a surface of the redistribution line.

13. The method according to claim 12 , wherein forming a layer of material comprises oxidizing copper.

14. The method according to claim 1 , wherein the covering material comprises a solder paste.

15. The method according to claim 14 , wherein forming solder over the solder pad comprises melting the solder paste.

16. The method according to claim 15 , wherein the uncovered portion of the redistribution line is passivated after melting the solder paste.

17. The method according to claim 16 , wherein the uncovered portion of the redistribution line is passivated by oxidation.

18. The method according to claim 1 , wherein forming the covering material comprises applying the covering material using a screen printing process.

19. A method of making a semiconductor component, the method comprising:

forming a seed layer over a surface of a semiconductor chip;

forming a mask over the seed layer, the mask having a mask opening;

forming a redistribution line within the mask opening;

covering a solder pad portion of the redistribution line;

forming a passivation layer over an uncovered portion of the redistribution line, the passivation layer also serving as a solder resist layer;

removing the mask;

applying solder over the surface of the semiconductor chip; and

forming a solder ball by melting the solder so that the solder adheres to the solder pad, the passivation layer serving as a resist layer to prevent the solder from adhering to portions of the redistribution line outside the solder pad.

20. The method according to claim 19 , wherein forming the passivation layer comprises forming a nickel layer.

21. The method according to claim 19 , wherein forming the passivation layer comprises forming a polymer layer.

22. The method according to claim 19 , wherein forming the passivation layer comprises oxidizing a surface of the redistribution line.

23. The method according to claim 19 , further comprising uncovering the solder pad before applying solder over the surface of the semiconductor chip.

24. The method according to claim 19 , wherein covering the solder pad comprises covering the solder pad with a flux material and wherein applying solder over the surface of the semiconductor chip comprises applying solder over the flux material.

25. A method of making a semiconductor component, the method comprising:

forming a redistribution line over a surface of a semiconductor chip, the redistribution line including a solder pad;

covering the solder pad with a solder paste;

melting the solder paste;

after melting the solder paste, forming a passivation layer over another portion of the redistribution line, wherein forming the passivation layer comprises oxidizing the other portion of the redistribution line;

applying solder over the surface of the semiconductor chip; and

forming a solder ball by melting the solder so that the solder adheres to the solder pad, the passivation layer serving as a resist layer to prevent the solder from adhering to the other portion of the redistribution line.

26. The method according to claim 25 , wherein forming the redistribution line comprises:

forming a seed layer over the surface of the semiconductor chip;

forming a mask over the seed layer, the mask having a mask opening; and

forming the redistribution line within the mask opening.

27. The method according to claim 25 , wherein covering the solder pad with a solder paste comprises performing a screen printing process.

28. The method according to claim 25 , wherein the solder paste comprises a material that includes small particles of solder bound in a flux.