FORMATION OF THE DIELECTRIC CAP LAYER FOR A REPLACEMENT GATE STRUCTURE

• US 20140299924A1
• Filed: 05/23/2014
• Published: 10/09/2014
• Est. Priority Date: 01/19/2012
• Status: Active Grant

• Current Assignee: Globalfoundries Singapore Pte Limited (GlobalFoundries, Inc.), International Business Machines Corporation
• Original Assignee: Globalfoundries Singapore Pte Limited (GlobalFoundries, Inc.), International Business Machines Corporation
• Inventors: XIE, Ruilong, HORAK, David V., FAN, Su Chen, PRANATHARTHI HARAN, Balasubramanian
• Granted Patent: US 8,957,465 B2
• Time in Patent Office: Days
• US Class Current: 257/288
• CPC Class Codes: H01L 21/28088 the final conductor layer next to the insulator being a composite, e.g. TiN
• CPC Class Codes: H01L 29/42376 characterised by the length or the sectional shape
• CPC Class Codes: H01L 29/4966 the conductor material next to the insulator being a composite material, e.g. organic material, TiN, MoSi2 H01L29/4908, H01L29/4983 take precedence
• CPC Class Codes: H01L 29/66545 using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence

Abstract

Gate to contact shorts are reduced by forming dielectric caps in replaced gate structures. Embodiments include forming a replaced gate structure on a substrate, the replaced gate structure including an ILD having a cavity, a first metal on a top surface of the ILD and lining the cavity, and a second metal on the first metal and filling the cavity, planarizing the first and second metals, forming an oxide on the second metal, removing the oxide, recessing the first and second metals in the cavity, forming a recess, and filling the recess with a dielectric material. Embodiments further include dielectric caps having vertical sidewalls, a trapezoidal shape, a T-shape, or a Y-shape.

Claims

1. A device comprising:

an interlayer dielectric (ILD) on substrate, the ILD having a cavity;

gate spacers on sidewalls of the cavity;

a first metal lining a bottom portion of the cavity between the gate spacers;

a second metal filling the bottom portion of the cavity; and

a dielectric cap in the top portion of the cavity.

2. The device according to claim 1, wherein the dielectric cap has a thickness of 10 nm to 40 nm.

3. The device according to claim 1, wherein the dielectric cap has vertical sidewalls.

4. The device according to claim 1, wherein the dielectric cap has a T-shape.

5. The device according to claim 1, wherein the dielectric cap has a Y-shape.

6. The device according to claim 1, wherein the dielectric cap has a trapezoidal shape with sidewalls closest to each other at a top surface of the first and second metals.

7. The device according to claim 1, wherein the dielectric cap comprises aluminum oxide (Al₂O₃), aluminum oxynitride (AlO_xN_y), aluminofluoride (AlF_x), or fluorinated aluminum oxide (AlF_xO_y).

8. The device according to claim 1, wherein the dielectric cap comprises SiN, SiO₂, or HfO₂.

9. The device according to claim 1, wherein the dielectric cap has slanted sidewalls.

10. The device according to claim 1, wherein the first metal comprises TiN.

11. The device according to claim 1, wherein the second metal comprises aluminum (Al).

12. The device according to claim 1, further comprising a metal gate between at least one of the gate spacers and the second metal.

13. The device according to claim 12, further comprising a source/drain region on either side of the metal gate.

14. A device comprising:

an interlayer dielectric (ILD) on substrate, the ILD having a cavity;

gate spacers on sidewalls of the cavity;

a first metal lining a bottom portion of the cavity between the gate spacers;

a second metal filling the bottom portion of the cavity; and

a dielectric cap having a trapezoidal shape in the top portion of the cavity, the dielectric cap comprising aluminum oxide (Al₂O₃), aluminum oxynitride (AlO_xN_y), aluminofluoride (AlF_x), or fluorinated aluminum oxide (AlF_xO_y).

15. The device according to claim 14, wherein the sidewalls of the trapezoidally-shaped dielectric cap are closest to each other at a top surface of the first and second metals

16. The device according to claim 14, wherein the first metal comprises TiN.

17. The device according to claim 14, wherein the second metal comprises aluminum (Al).

18. The device according to claim 14, further comprising a metal gate between at least one of the gate spacers and the second metal.

19. The device according to claim 14, wherein the dielectric cap has a thickness of 10 nm to 40 nm.

20. The device according to claim 18, further comprising a source/drain region on either side of the metal gate.