Backside Through Vias in a Bonded Structure

A method comprising:

• providing a first substrate, the first substrate having one or more first metallization layers disposed on a device side of the first substrate;
• providing a second substrate, the second substrate having one or more second metallization layers disposed on a device side of the second substrate;
• bonding the first substrate to the second substrate such that device side of the first substrate faces the device side of the second substrate;
• forming a patterned mask on a backside of the first substrate, the patterned mask having a first opening and a second opening;
• forming a first trench in the first substrate in the first opening of the patterned mask and a second trench in the first substrate in the second opening of the patterned mask, the first trench having a first width less than a second width of the second trench;
• and
• filling the first trench and the second trench with conductive material, thereby forming a first conductive plug and a second conductive plug.

A device comprising:

• a first substrate having a plurality of first metallization layers disposed thereon;
• a second substrate bonded to the first substrate, the second substrate having a plurality of second metallization layers;
• and
• a plurality of conductive plugs extending from a surface of the first substrate, the plurality of conductive plugs comprising a first conductive plug and a second conductive plug, the first conductive plug having a first width and a first depth, the second conductive plug having a second width and a second depth, the first width being greater than the second width, the first depth being greater than the second depth.