Alignment mark and method of formation

A structure comprising:

• a substrate comprising a through substrate via (TSV), the TSV extending from a front surface of the substrate to a back surface of the substrate;
• a conductive connector on the front surface of the substrate, the conductive connector configured to couple the substrate to an external component;
• an isolation layer on the back surface of the substrate, the isolation layer having a cavity, the cavity having isolation sidewalls and an isolation bottom surface adjoining the isolation sidewalls, no conductive feature extending through the isolation sidewalls or the isolation bottom surface;
• and
• a conductor positioned in the cavity and on the isolation sidewalls, the isolation layer being disposed between the conductor in the cavity and the substrate, a portion of the conductor extending on a first surface of the isolation layer distal from the substrate, the first surface adjoining at least one of the isolation sidewalls at a corner.

A method for forming a stacked device, the method comprising:

• providing a substrate having a through substrate via (TSV) protruding from a back side and having an external conductive connector on a front side, the back side and front side being opposite sides of the substrate;
• forming an isolation layer over the back side of the substrate, the isolation layer having a recess defined by isolation sidewalls and an adjoining isolation bottom surface;
• and
• after forming the isolation layer having the recess, forming a conductive layer in the recess, the isolation layer being disposed between the conductive layer in the recess and the substrate, the conductive layer being on the isolation sidewalls and the isolation bottom surface, wherein no conductive feature extends through the isolation sidewalls or the isolation bottom surface.

A structure comprising:

• a substrate;
• an alignment mark on a first area of a first side of the substrate, the first side of the substrate being opposite a second side of the substrate, the alignment mark comprising:
• a first isolation layer on the first side of the substrate,
• a second isolation layer on the first isolation layer, the second isolation having an opening to a first surface portion of the first isolation layer, the opening being electrically isolated through and between the first isolation layer and the second isolation layer, and
• a conductive material conformally on a second surface portion of the second isolation layer, a sidewall of the opening in the second isolation layer, and the first surface portion, the second surface portion of the second isolation layer being adjacent to the sidewall of the opening at a corner and being a portion of a surface of the second isolation layer distal from the substrate, the conductive material not fully filling the opening, the first isolation layer being disposed between the conductive material and the substrate;
• a through via extending from the second side of the substrate to the first side of the substrate, the through via being exposed through a second area of the first side of the substrate, the first area being distinct from the second area;
• and
• a conductive connector on the second side of the substrate, the conductive connector capable of coupling the substrate to an external component.