Redistribution Lines Having Nano Columns and Method Forming Same

A device comprising:

• a first passivation layer;
• a redistribution line comprising a seed layer and a conductive feature over the seed layer, wherein the conductive feature comprises:
• a via portion extending into the first passivation layer, wherein the via portion has a polycrystalline structure;
• a line portion, wherein the line portion comprises a plurality of nano columns over the via portion and the first passivation layer;
• and
• a second passivation layer extending on sidewalls and a top surface of the plurality of nano columns.

A device comprising:

• a dielectric layer;
• a metal seed layer contacting the dielectric layer, wherein the metal seed layer comprises first distinguishable edges opposite to each other, and the first distinguishable edges are over the dielectric layer;
• a first metal layer over and contacting the metal seed layer, wherein the first metal layer comprises a polycrystalline structure, and wherein the first metal layer comprises a first portion over the dielectric layer, and a second portion in the dielectric layer;
• and
• a second metal layer over and contacting the first metal layer, wherein the second metal layer comprises a first column comprising second distinguishable edges opposite to each other, and wherein the second distinguishable edges are laterally recessed from corresponding ones of the first distinguishable edges.