Bump structure for stacked dies

A semiconductor device comprising:

• a substrate;
• through vias extending through the substrate, the through vias comprising a conductive region extending through the substrate and a dielectric liner between the conductive region and the substrate, the conductive region and the dielectric liner protruding from a backside of the substrate;
• a first isolation film on the backside of the substrate between adjacent ones of the through vias, the conductive region of the through vias protruding from the first isolation film;
• a conductive element having a tapered sidewall and contacting at least one of the through vias, the conductive element being directly on the first isolation film and having a wider dimension along an interface between the conductive element and the first isolation film than at a location farther away from the interface between the conductive element and the first isolation film;
• a conductive conformal layer interposed between the protruding portion of the conductive region of the at least one through via and the conductive element, the conductive conformal layer having a different material composition than both the conductive region of the at least one through via and the conductive element;
• a second isolation film on the first isolation film and at least a portion of the conductive element;
• a contact barrier layer partially covering the conductive element;
• and
• a solder connection element on the contact barrier layer.

A semiconductor device comprising:

• a first substrate;
• a first isolation film over a first side of the first substrate;
• a conductive element having a tapered sidewall and a top surface over the first isolation film, the conductive element having a wider dimension along an interface between the conductive element and the first isolation film than at a location farther away from the interface between the conductive element and the first isolation film, the conductive element having a first thickness from the top surface of the conductive element to the first isolation film;
• a through via extending from a second side of the first substrate to the first side of the first substrate, the through via having a conductive region extending into the conductive element, the conductive element being wider than the through via at the interface between the conductive element and the first isolation film;
• a second isolation film on the first isolation film, the second isolation film being in direct contact with at least a portion of the top surface and the tapered sidewall of the conductive element, the second isolation film being a conformal film with a second thickness, the second thickness being less than the first thickness;
• and
• a contact barrier layer in direct contact with the conductive element.