Room temperature metal direct bonding
A bonded device structure including a first substrate having a first set of metallic bonding pads, preferably connected to a device or circuit, and having a first non-metallic region adjacent to the metallic bonding pads on the first substrate, a second substrate having a second set of metallic bonding pads aligned with the first set of metallic bonding pads, preferably connected to a device or circuit, and having a second non-metallic region adjacent to the metallic bonding pads on the second substrate, and a contact-bonded interface between the first and second set of metallic bonding pads formed by contact bonding of the first non-metallic region to the second non-metallic region. At least one of the first and second substrates may be elastically deformed.
1. A method of bonding substrates, comprising:
directly contacting a first non-metallic region proximate to a first plurality of metallic pads disposed on a first substrate with a second non-metallic region proximate to a plurality of metallic structures disposed on a second substrate;
after directly contacting the first and second non-metallic regions, bonding the first non-metallic region to the second non-metallic region without applying external pressure;
forming a contact between a first pad of the first plurality of metallic pads with a first structure of the plurality of metallic structures and generating pressure between the first pad and the first structure during said bonding the first non-metallic region to the second non-metallic region; and
heating the first and second substrates in a range of about 100-250° C.
2. A method as recited in claim 1 , wherein:
at least one of the first and second non-metallic regions comprises a silicon oxide layer.
3. A method as recited in claim 2 , comprising:
exposing the silicon oxide layer to one of an argon, nitrogen, and oxygen plasma.
4. A method as recited in claim 1 , comprising:
exposing at least one of the first and second non-metallic regions to a plasma process.
5. A method as recited in claim 1 , comprising:
exposing at least of one the first and second non-metallic regions to one of an argon, nitrogen, and oxygen plasma.
6. A method as recited in claim 1 , comprising:
polishing at least one of the first and second non-metallic regions to a surface roughness less than 15 angstroms.
7. A method as recited in claim 6 , comprising:
etching at least one of the first and second non-metallic regions after said polishing.
8. A method as recited in claim 1 , wherein:
each of the first pad and first structure has a substantially planar upper surface.
9. A method as recited in claim 8 , wherein:
said first and second non-metallic regions have substantially planar upper surfaces; and
said substantially planar upper surfaces of the first pad and first structure are below said substantially planar upper surfaces of said first and second non-metallic regions.
10. A method as recited in claim 1 , comprising:
bonding the first non-metallic region to the second non-metallic region in ambient.
11. A method as recited in claim 1 , comprising:
bonding the first non-metallic region to the second non-metallic region at room temperature.
12. A method as recited in claim 1 , wherein:
at least one of the first and second non-metallic regions comprises a silicon nitride layer.
13. A method as recited in claim 1 , wherein said plurality of metallic structures comprises a plurality of metal vias.