Bonded device structures including slotted redistribution layer pads and methods of fabrication thereof

A bonded device structure, comprising:

• a first device structure comprising:
• a first semiconductor substrate;
• first devices disposed on or in a first side of the first semiconductor substrate;
• a first interconnect structure over the plurality of first devices and the first side of the first semiconductor substrate, the first interconnect structure comprising metal features within an interconnect dielectric material;
• and
• a first bonding layer over the first interconnect structure, the first bonding layer comprising a plurality of first bonding pads laterally surrounded by a bonding layer dielectric material;
• and
• a second device structure comprising:
• a second semiconductor substrate;
• second devices disposed on, or in a first side of the second semiconductor substrate;
• a second interconnect structure over the second devices and the first side of the second semiconductor substrate, the second interconnect structure comprising metal features within an interconnect dielectric material;
• and
• a second bonding layer over the second interconnect structure, the second bonding layer comprising a plurality of second bonding pads surrounded by a bonding layer dielectric material;
• wherein the first bonding layer is bonded to the second bonding layer at a bonding interface to electrically and mechanically couple the first device structure to the second device structure, and wherein;
• the first device structure comprises a plurality of redistribution layer (RDL) pads and a first passivation layer laterally surrounding each of the RDL pads located between the first interconnect structure and the first bonding layer, an etch stop layer located between the plurality of RDL pads and the first passivation layer and the first bonding layer, and a second passivation layer located between the etch stop layer and the first bonding layer, wherein at least one of the RDL pads provides an electrical pathway between a first bonding pad of the first bonding layer and a metal feature of the first interconnect structure.

A method of fabricating a bonded device structure, comprising:

• depositing a metal material over a first redistribution structure of a first device structure;
• forming a plurality of openings in the metal material;
• depositing a dielectric material over the metal material and within the plurality of openings;
• performing a planarization process to remove portions of the dielectric material and the metal material and provide a redistribution layer (RDL) pad comprising a plurality of slots filled with the dielectric material and laterally surrounded by the metal material;
• forming a first bonding layer over the RDL pad and a bonding pad via extending between a bonding pad of the first bonding layer and an upper surface of the RDL pad;
• and
• bonding the first bonding layer of the first device structure to a second bonding layer of a second device structure to bond the first device structure to the second device structure.