Metal gate structure and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-10163626-B2
Application number	US-201615375266-A
Country	US
Kind code	B2
Filing date	Dec 12, 2016
Priority date	Dec 12, 2016
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

An NMOS transistor gate structure includes at least one spacer defining a gate region over a semiconductor substrate, a gate dielectric layer disposed on the gate region and lining an inner sidewall of the spacer, a bottom barrier layer conformally disposed on the gate dielectric layer, a work function metal layer disposed on the bottom barrier layer, and a filling metal partially wrapped by the work function metal layer. The bottom barrier layer has an oxygen concentration higher than a nitrogen concentration. The bottom barrier layer is in direct contact with the gate dielectric layer. The bottom barrier layer includes a material selected from Ta, TaN, TaTi, TaTiN and a combination thereof.

First claim

What is claimed is:

1. A method of manufacturing NMOS gate structure, comprising:
forming at least one dummy gate stack;
forming an inter-layer dielectric (ILD) layer around the dummy gate stack;
removing the dummy gate stack to form at least one recess;
forming a gate dielectric layer on a bottom surface and sidewalls of the recess;
forming a bottom barrier layer on the gate dielectric layer;
oxidizing a portion of the bottom barrier layer, wherein the oxidized portion of the bottom barrier layer has a nitrogen concentration and an oxygen concentration higher than the remaining portion of the bottom barrier layer;
forming a work function metal layer on the bottom barrier layer; and
filling a remaining portion of the recess with a filling metal.

2. The method of claim 1 , wherein before oxidizing the portion of the bottom barrier layer comprises:
depositing a mask layer on the bottom barrier layer; and
patterning the mask layer to expose the portion of the bottom barrier layer.

3. The method of claim 1 , wherein oxidizing the portion of the bottom barrier layer comprises:
treating the bottom barrier layer with a chemical solution containing an oxidizing agent and ammonium ions.

4. The method of claim 3 , wherein the oxidizing agent comprises H 2 O 2 .

5. The method of claim 3 , wherein the oxidizing agent comprises an acid with ClO 3 − , ClO − , or NO 3 − .

6. The method of claim 1 , wherein oxidizing the portion of the bottom barrier layer comprises:
exposing the bottom barrier layer to ozonated deionized water; and
treating the bottom barrier layer with a chemical solution containing ammonium ions.

7. The method of claim 1 , wherein the bottom barrier layer includes a material selected from Ta, TaN, TaTi, TaTiN and a combination thereof.

8. The method of claim 1 , wherein the oxygen concentration is higher than the nitrogen concentration at the portion of the bottom barrier layer.

9. A method of manufacturing metal gate structure, the method comprising:
forming a gate dielectric layer;
forming a bottom barrier layer on the gate dielectric layer;
oxidizing a portion of the bottom barrier layer, wherein the oxidized portion of the bottom barrier layer has a nitrogen concentration and an oxygen concentration higher than a nitrogen concentration and an oxygen concentration in the remaining portion of the bottom barrier layer; and;
forming a metal layer on the bottom barrier layer.

10. The method of claim 9 , wherein before oxidizing the portion of the bottom barrier layer comprises:
depositing a mask layer on the bottom barrier layer; and
patterning the mask layer to expose the portion of the bottom barrier layer.

11. The method of claim 9 , wherein oxidizing the portion of the bottom barrier layer comprises:
treating the bottom barrier layer with a chemical solution containing an oxidizing agent and ammonium ions.

12. The method of claim 11 , wherein the oxidizing agent comprises H 2 O 2 .

13. The method of claim 11 , wherein the oxidizing agent comprises an acid with ClO 3 − , ClO − , or NO 3 − .

14. The method of claim 9 , wherein oxidizing the portion of the bottom barrier layer comprises:
exposing the bottom barrier layer to ozonated deionized water; and
treating the bottom barrier layer with a chemical solution containing ammonium ions.

15. The method of claim 9 , wherein oxidizing the portion of the bottom barrier layer comprises:
exposing the bottom barrier layer to oxygen plasma; and
treating the bottom barrier layer with a chemical solution containing ammonium ions.

16. A method, comprising:
forming a gate dielectric layer over a substrate;
forming a tantalum-containing layer over the gate dielectric layer;
treating a portion of the tantalum-containing layer with oxygen to form a Ta—O dipole-containing layer, wherein the treated portion of the tantalum-containing layer has a nitrogen concentration and an oxygen concentration higher than a nitrogen concentration and an oxygen concentration in an untreated portion of the tantalum-containing layer; and
forming a metal layer over the Ta—O dipole-containing layer.

17. The method of claim 16 , wherein the treating the tantalum-containing layer with the oxygen is performed using a chemical solution containing oxidizing agent.

18. The method of claim 16 , wherein the treating the tantalum-containing layer with the oxygen is performed using a plasma containing oxygen.

19. The method of claim 16 , further comprising treating the tantalum-containing layer with nitrogen.

20. The method of claim 19 , wherein the treating the tantalum-containing layer with the nitrogen is performed using a chemical solution containing ammonium ions.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Lin Ming-Huei
• Chen Yen-Yu
• Tsao Chih-Pin
• Chang Shih-Hsun

Classifications

• H10P14/6319

  Formation by plasma treatments, e.g. plasma oxidation of the substrate · CPC title

• H10P14/6318

  Formation by simultaneous oxidation and nitridation · CPC title

• H10P14/6316

  Formation by nitridation, e.g. nitridation of the substrate · CPC title

• H10P14/6314

  of a metallic layer · CPC title

• H10W20/065

  by making at least a portion of the conductive part non-conductive, e.g. by oxidation · CPC title