Hybrid bonding interface for 3-dimensional chip integration
View Patent ↗Each of a first substrate and a second substrate includes a surface having a diffusion resistant dielectric material such as silicon nitride. Recessed regions are formed in the diffusion resistant dielectric material and filled with a bondable dielectric material. The patterns of the metal pads and bondable dielectric material portions in the first and second substrates can have a mirror symmetry. The first and second substrates are brought into physical contact and bonded employing contacts between metal pads and contacts between the bondable dielectric material portions. Through-substrate-via (TSV) structures are formed through bonded dielectric material portions. The interface between each pair of bonded dielectric material portions located around a TSV structure is encapsulated by two diffusion resistant dielectric material layers so that diffusion of metal at a bonding interface is contained within each pair of bonded dielectric material portions.
1. A method of forming a bonded structure, said method comprising:
forming a first bondable dielectric material portion within a first diffusion resistant dielectric material layer that is located in a first substrate;
forming a second bondable dielectric material portion within a second diffusion resistant dielectric material layer that is located in a second substrate;
brining said first substrate and said second substrate into contact with each other and bonding said first and second bondable dielectric material portions to form a bonded dielectric material portion;
forming a through-substrate-via (TSV) cavity that extends through said bonded dielectric material portion, whereby said bonded dielectric material portion contains a hole therethrough; and
forming a through-substrate-via (TSV) structure extending through said first substrate and said second substrate by filling said TSV cavity.
2. The method of claim 1 , wherein, upon formation of said TSV structure, said bonded dielectric material portion laterally surrounds a portion of said TSV structure and is encapsulated by said first and second diffusion resistant dielectric material layers and said TSV structure.
3. The method of claim 1 , further comprising:
recessing a portion of said first diffusion resistant dielectric material layer;
filling said recessed region of said first diffusion resistant dielectric material layer with a first bondable dielectric material;
planarizing said first bondable dielectric material to form said first bondable dielectric material portion;
recessing a portion of said second diffusion resistant dielectric material layer;
filling said recessed region of said second diffusion resistant dielectric material layer with a second bondable dielectric material; and
planarizing said second bondable dielectric material to form said second bondable dielectric material portion.
4. The method of claim 3 , wherein an exposed surface of said first bondable dielectric material portion is coplanar with an exposed surface of said first diffusion resistant dielectric material layer after planarization of said first bondable dielectric material, and an exposed surface of said second bondable dielectric material portion is coplanar with an exposed surface of said second diffusion resistant dielectric material layer after planarization of said second bondable dielectric material.
5. The method of claim 1 , further comprising:
forming a first metal pad in said first diffusion resistant dielectric material layer; and
forming a second metal pad in said first diffusion resistant dielectric material layer, wherein said second metal pad is bonded to said first metal pad after brining said first and second substrates into contact with each other and before forming said TSV cavity.
6. The method of claim 5 , further comprising:
recessing a portion of said first diffusion resistant dielectric material layer;
filling said recessed region of said first diffusion resistant dielectric material layer with a first metal;
planarizing said first metal to form said first metal pad;
recessing a portion of said second diffusion resistant dielectric material layer;
filling said recessed region of said second diffusion resistant dielectric material layer with a second metal; and
planarizing said second metal to form said second metal pad.
7. The method of claim 1 , further comprising:
forming a through-substrate-via (TSV) liner on sidewalls of said TSV cavity; and
forming a through-substrate-via (TSV) fill portion on sidewalls of said TSV liner, wherein said TSV cavity is filled by said TSV fill portion, and said TSV liner and said TSV fill portion collectively constitute said TSV structure.
8. The method of claim 7 , wherein said TSV fill portion is formed by electroplating or electroless plating.
9. The method of claim 1 , wherein said first and second bondable dielectric material portions are portions of silicon oxide and said first and second diffusion resistant dielectric material layers are layers of silicon nitride.
10. The method of claim 1 , wherein said first bondable dielectric material portion is formed by:
forming a first recessed region in said first diffusion resistant dielectric material layer;
filling said first recessed region with a first bondable dielectric material; and
planarizing said first bondable dielectric material to form said first bondable dielectric material portion.
11. The method of claim 10 , wherein an exposed surface of said first bondable dielectric material portion is coplanar with, or is raised by no more than 1 nm relative to, an exposed surface of said first diffusion resistant dielectric material layer after planarization of said first bondable dielectric material.
12. The method of claim 10 , wherein said first bondable dielectric material is doped silicon oxide or undoped silicon oxide.
13. The method of claim 10 , wherein said second bondable dielectric material portion is formed by:
forming a second recessed region in said second diffusion resistant dielectric material layer;
filling said second recessed region with a second bondable dielectric material; and
planarizing said second bondable dielectric material to form said second bondable dielectric material portion.
14. The method of claim 10 , wherein an exposed surface of said second bondable dielectric material portion is coplanar with, or is raised by no more than 1 nm relative to, an exposed surface of said second diffusion resistant dielectric material layer after planarization of said second bondable dielectric material.
15. The method of claim 10 , wherein said second bondable dielectric material is doped silicon oxide or undoped silicon oxide.
16. The method of claim 1 , further comprising:
forming a first metal pad in said first diffusion resistant material layer; and
forming a second metal pad in said second diffusion resistant material layer, wherein said first metal pad and said second metal pad are bonded simultaneously with the formation of said bonded dielectric material portion.
17. The method of claim 16 , wherein said first metal pad is formed by:
forming a recessed region in said first diffusion resistant dielectric material layer;
filling said recessed region in said first diffusion resistant dielectric material layer with a first metal layer;
planarizing said first metal layer to form said first metal pad.
18. The method of claim 17 , wherein said second metal pad is formed by:
forming a recessed region in said second diffusion resistant dielectric material layer;
filling said recessed region in said second diffusion resistant dielectric material layer with a second metal layer;
planarizing said second metal layer to form said second metal pad.
19. The method of claim 1 , wherein said first diffusion resistant dielectric material layer and said second diffusion resistant dielectric material layer comprise silicon nitride.
20. The method of claim 1 , wherein said TSV structure is formed by:
depositing a TSV liner contacting sidewalls of said TSV cavity; and
depositing a TSV fill portion on sidewalls of said TSV liner, wherein said TSV liner and said TSV fill portion completely fill said TSV cavity.