Semiconductor device

A semiconductor device, comprising:

• first and second conductive features disposed in a substrate and adjacent to each other;
• and
• first and second metal bumps disposed over and electrically connected to the first and second conductive features, respectively,
• wherein a top surface of one of the first and second metal bumps is curved in a center region but substantially planar in an edge region, and
• wherein an etch stop layer laterally extends between the first and second metal bumps and contacts the first and second metal bumps, a protection layer encapsulates a top and a sidewall of a passivation stack between the first and second bumps and contacts the first and second metal bumps, and the etch stop layer and the protection layer comprise different materials.

A semiconductor device, comprising:

• a conductive feature of an interconnection structure disposed over a substrate;
• a metal bump disposed over and electrically connected to the conductive feature;
• first and second stacked structures disposed over the substrate respectively at first and second sides of the metal bump, wherein locations of the first and second stacked structures are not overlapped with a location of the metal bump;
• and
• a protection layer encapsulating tops and sidewalls of the first and second stacked structures and extending downwardly and continuously along a sidewall of the substrate.