Conductive contacts having varying widths and method of manufacturing same

A bump structure, comprising:

• a contact element formed over a substrate;
• a passivation layer overlying the substrate, the passivation layer having a passivation opening exposing the contact element;
• a polyimide layer overlying the passivation layer, the polyimide layer having a polyimide opening exposing the contact element, wherein the polyimide opening has a polyimide width at a surface of the polyimide layer closest to the substrate, wherein the passivation opening has a passivation width, and wherein the polyimide width is greater than the passivation width;
• an under bump metallurgy (UBM) feature overlying portions of the polyimide layer and the passivation layer and electrically coupled with the contact element;
• and
• a copper pillar on the under bump metallurgy feature.

A method of forming a bump structure, comprising:

• forming a contact element over a substrate;
• forming a passivation layer over the substrate, the passivation layer having a passivation opening exposing the contact element;
• forming a polyimide layer over the passivation layer, the polyimide layer having a polyimide opening exposing the contact element;
• electrically coupling an under bump metallurgy (UBM) feature with the contact element, the under bump metallurgy feature having a UBM width;
• and
• forming a copper pillar on the under bump metallurgy feature, a distal end of the copper pillar having a pillar width, the UBM width greater than the pillar width, wherein a portion of the copper pillar over a topmost surface of the under bump metallurgy feature has a substantially linear profile.