3D bonded semiconductor structure with an embedded capacitor

1. A method of forming a three-dimensional (3D) bonded semiconductor structure, said method comprising:

providing a first semiconductor structure including a first wafer, a first interconnect structure, and a first bonding oxide layer containing at least one first metallic structure embedded therein, and a second semiconductor structure including a second wafer, a second interconnect structure, and a second bonding oxide layer containing at least one second metallic structure embedded therein;

forming a high-k dielectric material on a surface of said at least one first metallic structure;

performing a nitridation process to provide a first nitrided surface layer comprising first nitridized oxide regions in an upper portion of said first bonding oxide layer and a nitridized high-k dielectric material in at least an upper portion of said high-k dielectric material, and to provide a second nitrided surface layer comprising second nitridized oxide regions in an upper portion of said second bonding oxide layer and a nitridized metallic region in an upper portion of said at least one second metallic structure;

removing nitrogen from said nitridized metallic region to convert said nitridized metallic region into a region that has a same composition as said second metallic structure; and

bonding said first semiconductor structure to said second semiconductor structure, wherein said bonding provides a bonding interface between the first and second nitridized oxide regions and another bonding interface between said nitridized high-k dielectric material and said at least one second metallic structure.

2. The method of claim 1 wherein said performing said nitridation process comprises a thermal nitridation process, wherein said thermal nitridation process is performed at a temperature from 50° C. to 500° C. in a nitrogen-containing ambient.

3. The method of claim 1 , wherein said performing said nitridation process comprises a plasma nitridation process, wherein said plasma nitridation process is performed at a temperature from 50° C. to 500° C. in a nitrogen-containing ambient.

4. The method of claim 1 , further comprising performing a pre-back step prior to said nitridation process, wherein said pre-back step is performed at a temperature from 100° C. to 700° C. in nitrogen or a mixture of nitrogen and hydrogen.

5. The method of claim 1 , wherein said removing nitrogen from said second nitridized metallic region is performed in a gaseous or plasma ambient of hydrogen, helium or a mixture thereof, and at a temperature from 80° C. to 350° C.

6. The method of claim 1 , wherein said bonding comprises:

performing wafer to wafer alignment;

bringing said first semiconductor structure into intimate contact with said second semiconductor structure; and

annealing at a temperature from 100° C. to 700° C. and in ambient including at least one of nitrogen, hydrogen, and helium.

7. The method of claim 1 , wherein said first metallic structure is recessed prior to forming said high-k dielectric material.

8. The method of claim 1 , wherein said first and second metallic structures comprise tantalum, tungsten, cobalt, rhodium, ruthenium, aluminum, copper or alloys thereof.

9. The method of claim 1 , wherein said first and second nitridized oxide regions comprise an oxide and added nitrogen, said nitridized high-k dielectric material comprises a high-k dielectric material and added nitrogen, and nitridized metallic region comprises copper, a copper-aluminum alloy, a copper manganese alloy, aluminum or an aluminum-copper alloy and added nitrogen.

10. The method of claim 9 , wherein said added nitrogen is present in an amount of from 10 atomic percent nitrogen to 50 atomic percent nitrogen.

11. The method of claim 1 , wherein said first and second bonding oxide layers are composed of a same dielectric oxide.

12. The method of claim 11 , wherein said dielectric oxide is silicon dioxide.

13. The method of claim 11 , wherein said dielectric oxide is tetraethylorthosilicate or fluorinated tetraethylorthosilicate.

14. The method of claim 1 , wherein the high-k dielectric material is selected from the group consisting of HfO 2 , ZrO 2 , La 2 O 3 , Al 2 O 3 , TiO 2 , SrTiO 3 , LaAlO 3 , Y 2 O 3 , HfO x N y , ZrO x N y , La 2 O x N y , Al 2 O x N y , TiO x N y , SrTiO x N y , LaAlO x N y , Y 2 O x N y , SiON, SiN x , a silicate thereof, and an alloy thereof, and wherein x is from 0.5 to 3 and y is from 0 to 2.

15. The method of claim 1 , wherein said removing nitrogen from said second nitridized metallic region is performed selective to said second nitridized oxide regions.

16. The method of claim 15 , wherein said removing nitrogen from said second nitridized metallic region comprises a reductive process.

17. The method of claim 1 , wherein said bonding comprising a bonding anneal, said bonding anneal is performed at a temperature from 100° C. to 700° C. and in ambient including at least one of nitrogen, hydrogen, and helium.

18. The method of claim 1 , wherein said bonding provides a three-dimensional bonded semiconductor structure in which said first metallic structure, said nitridized high-k material, a remaining portion of said high-k material and said second metallic structure form a capacitor.

19. The method of claim 1 , wherein said nitridation process converts an entirety of said high-k dielectric material into said nitridized high-k material.

20. The method of claim 19 , wherein said bonding provides a three-dimensional bonded semiconductor structure in which said first metallic structure, said nitridized high-k material and said second metallic structure form a capacitor.