Conductive barrier direct hybrid bonding

A method of bonding substrates, comprising:

• forming first and second pluralities of metallic contact structures in respective upper surfaces of first and second substrates, where a first top surface of said first plurality of metallic contact structures is below said upper surface of said first substrate and a second top surface of said second plurality of metallic contact structures is below said upper surface of said second substrate;
• forming respective first layers of conductive barrier material over said respective upper surfaces and said first and second pluralities of metallic contact structures and said first and second substrates, said respective first layers of conductive barrier material comprising respective first exposed portions over said respective upper surfaces of said first and second substrates;
• removing said first exposed portions of said first layers of conductive barrier material from said upper surfaces of said first and second substrates to leave respective second exposed portions of said conductive barrier material on said first and second pluralities of metallic contact structures, said second exposed portions of said first layers of conductive barrier material comprising exposed top surfaces disposed below said respective upper surfaces;
• directly bonding the upper surface of said first substrate to the upper surface of said second substrate;
• and
• directly bonding the remaining portion of said conductive barrier material on said first plurality of metallic contact structures to the respective remaining portion of said conductive material on said second plurality of metallic contact structures.