Under-bump metallization structures and associated methods of formation

An apparatus comprising:

• a first layer comprising a first material, wherein the first layer has a width parallel to a first direction, a depth parallel to a second direction, and a height parallel to a third direction;
• a second layer comprising a second material formed on at least a top surface of the first layer, the top surface of the first layer extending along the first direction and the second direction;
• a void formed in the second layer, wherein extents of the void comprise sidewalls of the second layer and a portion of the top surface of the first layer, wherein the sidewalls of the second layer are parallel to the third direction;
• and
• one or more layers formed on the sidewalls of the second layer and on the portion of the top surface of the first layer, the one or more layers for coupling the first layer with a bonding material.

A product formed by a method comprising:

• forming a first layer comprising a first material, wherein a top surface of the first layer extends along a first direction and a second direction, the first direction parallel to a width of the first layer and the second direction parallel to a depth of the first layer;
• forming, on at least the top surface of the first layer, a second layer comprising a second material;
• forming a void in the second layer, wherein forming the void exposes a portion of the top surface of the first layer,
• forming one or more layers on a top surface of the second layer and on the exposed portion of the top surface of the first layer;
• and
• performing a material removal operation, wherein the material removal operation lifts portions of the one or more layers formed on the top surface of the second layer off of the top surface.