Integrated circuit packages and methods of forming the same

A method comprising:

• forming a first mask having a first opening;
• plating a first conductive material in the first opening;
• removing the first mask;
• forming a second mask on the first conductive material, a second opening in the second mask exposing a portion of the first conductive material;
• plating a second conductive material in the second opening and on the exposed portion of the first conductive material, the second conductive material plated directly from the first conductive material with a plurality of plating speeds, the second conductive material having curved sidewalls, wherein after plating at least a portion of the curved sidewalls is spaced apart by an air gap from sidewalls of the second opening;
• and
• removing the second mask.

A method comprising:

• forming a dielectric layer;
• forming an under-bump metallurgy layer having a line portion on the dielectric layer and having a via portion extending through the dielectric layer;
• forming a mask on the under-bump metallurgy layer, the mask having an opening exposing the line portion of the under-bump metallurgy layer;
• forming a through via in the opening and on the line portion of the under-bump metallurgy layer by plating a conductive material with a workpiece oriented vertically in a plating solution, wherein forming the through via comprises:
• plating a lower portion of the conductive material by initially plating with a first plating speed and then with a second plating speed to create curved sidewalls, the second plating speed being different than the first plating speed;
• plating a middle portion of the conductive material with a third plating speed to create straight sidewalls;
• and
• plating an upper portion of the conductive material by initially plating with a fourth plating speed and then with a fifth plating speed to create curved sidewalls, the fifth plating speed being different than the fourth plating speed, the through via having a first curved sidewall proximate the via portion in a cross-sectional view, the through via having a second curved sidewall distal the via portion, the first curved sidewall having a longer arc length extending from the line portion to an upper surface of the through via than the second curved sidewall extending from the line portion to the upper surface of the through via;
• and
• removing the mask.