3DIC structure and method of fabricating the same

A three dimensional integrated circuit (3DIC) structure, comprising:

• a first die having a first pad and a second die having a second pad;
• a hybrid bonding structure bonding the first die and the second die, wherein the hybrid bonding structure comprises:
• a dielectric layer between the first die and the second die;
• and
• a conductive feature disposed in the dielectric layer, wherein the conductive feature comprises:
• a first via plug electrically connected to the first die;
• a second via plug electrically connected to the second die;
• and
• a middle portion electrically connected to the first via plug and the second via plug, wherein the middle portion is disposed between and in direct contact with the first via plug and the second via plug,
• wherein the first pad is separated from the second pad by a portion of the dielectric layer, and a height of the middle portion is greater than a distance between the first pad of the first die and the second pad of the second die.

A method of fabricating a three dimensional integrated circuit (3DIC) structure, comprising:

• forming a first die, comprising:
• forming a first interconnect structure over a substrate;
• forming a first pad over the first interconnect structure, wherein the first pad is electrically connected to the first interconnect structure;
• bonding the first die to a second die having a second interconnect structure and a second pad electrically connected to the second interconnect structure through a hybrid bonding structure, wherein the hybrid bonding structure is disposed between the first interconnect structure and the second interconnect structure, the hybrid bonding structure comprises a first bonding structure covering the first pad and a second bonding structure covering the second pad, wherein foi ming the first bonding structure comprises:
• forming a bonding dielectric layer over the first interconnect structure;
• and
• forming a bonding metal layer in the bonding dielectric layer to electrically connect to the first interconnect structure, wherein the bonding metal layer comprises a via plug and a metal feature formed over and in direct contact with the via plug, a height of the metal feature is greater than a height of the via plug,
• wherein the first pad is laterally aside the bonding metal layer, and separated from the second pad by the bonding dielectric layer therebetween, and a bottom surface of the metal feature contacting the via plug is lower than a top surface of the first pad of the first die.