Semiconductor Device and Method

A semiconductor device comprising:

• a first redistribution line and a second redistribution line over a semiconductor substrate;
• a first under-bump metallurgy (UBM) structure over and electrically coupled to the first redistribution line, wherein a top surface of the first UBM structure is concave, and wherein the first UBM structure has a first width;
• and
• a second UBM structure over and electrically coupled to the second redistribution line, wherein a bottom surface of the second UBM structure is level with a bottom surface of the first UBM structure, wherein the second UBM structure has a second width less than the first width, and wherein a top surface of the second UBM structure is less concave than the top surface of the first UBM structure.

A semiconductor device comprising:

• a first conductive feature and a second conductive feature over a semiconductor substrate;
• a first insulating layer over the first conductive feature and the second conductive feature;
• a first under-bump metallurgy (UBM) structure over and electrically coupled to the first conductive feature, the first UBM structure extending through the first insulating layer, wherein a top surface of the first UBM structure is a concave surface;
• and
• a second UBM structure over and electrically coupled to the second conductive feature, the second UBM structure extending through the first insulating layer, wherein a top surface of the second UBM structure is flat or convex, wherein a first height of the first UBM above the first insulating layer is different than a second height of the second UBM above the first insulating layer.