Electronic devices having tapered edge walls

1. An electronic device, comprising:

a substrate;

a structure over the substrate, the structure having an edge wall defining at least a portion of an opening exposing a surface of the substrate; and

a dielectric material laterally adjacent and in contact with the edge wall of the structure, the dielectric material also in contact with an adjacent portion of the surface of the substrate, the dielectric material having a profile tapering downward from adjacent the edge wall toward the substrate,

the structure comprising a different material than the dielectric material.

2. The electronic device of claim 1 , wherein the profile comprises a profile selected from the group consisting of a linear profile, a concave profile, and a convex profile.

3. The electronic device of claim 1 , wherein the structure comprises a mask structure.

4. The electronic device of claim 1 , wherein the structure comprises a conductive structure.

5. The electronic device of claim 4 , wherein the conductive structure comprises a trace or a bond pad.

6. The electronic device of claim 1 , wherein the dielectric material entirely surrounds an interface between the structure and the substrate.

7. The electronic device of claim 1 , further comprising an underfill material over the dielectric material.

8. The electronic device of claim 7 , wherein the underfill material comprises a nonconductive epoxy-based material.

9. The electronic device of claim 7 , wherein the underfill material has a thickness from about 10 μm to about 50 μm.

10. The electronic device of claim 1 , wherein the profile of the dielectric material exhibits a convex profile curving outward away from an interface between the structure and the substrate.

11. An electronic device, comprising:

a substrate;

a solder mask over the substrate, the solder mask defining an opening therethrough;

a supplemental mask within the opening of the solder mask, the supplemental mask having a sidewall that slopes away from the solder mask and exhibits a convex surface curving outward away from an interface between the solder mask and the substrate; and

a conductive structure adjacent and in contact with at least one of the solder mask or the supplemental mask.

12. The electronic device of claim 11 , further comprising another conductive material over and in contact with the conductive structure.

13. The electronic device of claim 12 , wherein the another conductive material comprises a pillar.

14. The electronic device of claim 12 , wherein the another conductive material comprises a material selected from the group consisting of solder, gold, copper, a conductive resin, and a conductor-filled resin.

15. The electronic device of claim 11 , wherein the supplemental mask intersects a major surface of the substrate at an angle between about 10° and about 80°.

16. The electronic device of claim 11 , wherein the supplemental mask has another sidewall that exhibits a concave surface curving inward toward the interface between the solder mask and the substrate.

17. The electronic device of claim 11 , wherein the supplemental mask has a maximum thickness in a direction normal to a major surface of the substrate, in a range from about 1 μm to about 1000 μm.

18. The electronic device of claim 11 , wherein the solder mask comprises a polymer.

19. The electronic device of claim 18 , wherein the solder mask comprises an epoxy.

20. The electronic device of claim 11 , wherein the substrate comprises a printed circuit board.