Method to etch copper barrier film

Patent metadata

Field	Value
Publication number	US-9570320-B2
Application number	US-201414579822-A
Country	US
Kind code	B2
Filing date	Dec 22, 2014
Priority date	Oct 9, 2014
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A method of opening a barrier film below copper structures in a stack is provided. A pulsed gas is provided into a plasma processing chamber, wherein the providing the pulsed gas comprises providing a pulsed H 2 containing gas and providing a pulsed halogen containing gas, wherein the pulsed H 2 containing gas and the pulsed halogen containing gas are pulsed out of phase, and wherein the pulsed H 2 containing gas has an H 2 high flow period and the pulsed halogen containing gas has a halogen containing gas high flow period, wherein the H 2 high flow period is greater than the halogen containing gas high flow period. The pulsed gas is formed into a plasma. The copper structures and the barrier film are exposed to the plasma, which etches the barrier film. In another embodiment, a wet and dry cyclical process may be used.

First claim

What is claimed is:

1. A method of opening a barrier film below copper structures in a stack in a dry plasma etch chamber, comprising:
placing the stack in a dry plasma etch chamber;
providing a pulsed gas into the plasma etch chamber, wherein the providing the pulsed gas comprises:
providing a pulsed H 2 containing gas; and
providing a pulsed halogen containing gas, wherein the pulsed H 2 containing gas and the pulsed halogen containing gas are pulsed out of phase, and wherein the pulsed H 2 containing gas has an H 2 high flow period and the pulsed halogen containing gas has a halogen containing gas high flow period, wherein the H 2 high flow period is greater than the halogen containing gas high flow period;

forming the pulsed gas into a plasma;
exposing the copper structures and the barrier film to the plasma, which etches the barrier film.

2. The method, as recited in claim 1 , wherein the forming the pulsed gas into a plasma, comprises:
providing an RF power signal that is constant during the providing the pulsed gas into the plasma processing chamber; and
providing a bias power that is constant during the providing the pulsed gas into the plasma processing chamber.

3. The method, as recited in claim 2 , further comprising a constant flow of an inert carrier gas during the providing the pulsed gas into the plasma processing chamber.

4. The method, as recited in claim 3 , wherein the halogen containing gas comprises at least one of HBr, BCl 3 , Cl 2 , CF 4 , or NF 3 .

5. The method, as recited in claim 1 , wherein a ratio of the H 2 high flow period to the halogen containing gas high flow period is between 2:1 to 20:1 inclusive.

6. The method, as recited in claim 5 , wherein the H 2 containing gas and halogen containing gas are pulsed completely out of phase.

7. The method, as recited in claim 1 , further comprising a constant flow of an inert carrier gas during the providing the pulsed gas into the plasma processing chamber.

8. The method, as recited in claim 1 , wherein the barrier film comprises at least one of Co, Ru, or Ta, Ti, TaN, or TiN.

9. The method, as recited in claim 1 , wherein the forming the pulsed gas into a plasma, comprises:
providing an RF power signal that is pulsed during the providing the pulsed gas into the plasma processing chamber; and
providing a bias power that is pulsed during the providing the pulsed gas into the plasma processing chamber.

10. A method of opening a barrier film comprising at least one of Co, Ru, or Ta, Ti. TaN, or TiN below copper structures in a stack, comprising:
placing the stack in a dry plasma processing chamber;
providing a constant flow of an inert carrier gas;
providing a pulsed gas into the plasma processing chamber, wherein the providing the pulsed gas comprises:
providing a pulsed H 2 containing gas; and
providing a pulsed halogen containing gas, comprising at least one of HBr, BCl 3 , Cl 2 , CF 4 , or NF 3 , wherein the pulsed H 2 containing gas and the pulsed halogen containing gas are pulsed out of phase, and wherein the pulsed H 2 containing gas has an H 2 high flow period and the pulsed halogen containing gas has a halogen containing gas high flow period, wherein a ratio of the H 2 high flow period to the halogen containing gas high flow period is between 2:1 to 20:1 inclusive;

forming the constant flow gas and pulsed gas into a plasma, comprising:
providing an RF power signal between 200 and 1000 Watts during the providing the constant flow gas and pulsed gas into the plasma processing chamber; and
providing a bias power between 50 and 500 volts during the providing the constant flow gas and pulsed gas into the plasma processing chamber;

exposing the copper structures and the barrier film to the plasma, which etches the barrier film.

11. A method of opening a barrier film below copper structures, comprising providing a wet and dry treatment comprising at least one cycle, wherein each cycle comprises sequential steps of:
providing a wet treatment of the barrier film below the copper structures;
providing a dry plasma sputtering of the barrier film below the copper structures; and
providing a dry halogen containing etch after providing the wet and dry treatment, comprising:
providing a continuous inert gas;
providing a pulsed H 2 gas;
providing a pulsed halogen containing gas, which is out of phase with the pulsed H 2 gas;
forming a plasma, which etches remaining barrier film;

wherein the cycle is repeated at least 3 times, and
wherein providing a wet treatment provides an acidic, buffer, or chelator bath or a bath comprising at least one of acetyl acetone, hexafluoroacetylacetone or hydrogen peroxide, and
wherein the barrier film comprises at least one of Co, Ru, or Ta, Ti. TaN, TiN.

12. The method, as recited in claim 11 , further comprising:
providing a carbon, SiN, or aluminum oxide deposition on the copper structures after the providing the wet and dry treatment and before the dry halogen containing etch of remaining barrier film.

13. The method, as recited in 11 , wherein the providing the halogen containing etch, comprises:
providing an etch gas comprising H 2 and a halogen; and
forming the etch gas into a plasma.

14. The method, as recited in claim 11 , wherein the dry plasma sputtering is halogen free.

15. The method, as recited in claim 11 , wherein the dry plasma sputtering has a low halogen contents such that it does not cause Cu corrosion.

16. The method, as recited in claim 11 , further comprising providing a bias of between to 50 to 400 volts, and wherein the forming the plasma comprises providing a RF power of 200 to 1000 Watts.

17. A method of opening a barrier film below copper structures, comprising providing a wet and dry treatment comprising at least one cycle, wherein each cycle comprises sequential steps of:
providing a wet treatment of the barrier film below the copper structures;
providing a dry plasma sputtering of the barrier film below the copper structures; and
providing a dry halogen containing etch after providing the wet and dry treatment, comprising:
providing a continuous inert gas;
providing a pulsed H 2 gas;
providing a pulsed halogen containing gas, which is out of phase with the pulsed H 2 gas; and
forming a plasma, which etches remaining barrier film.

18. The method, as recited in claim 17 , further comprising:
providing a carbon, SiN, or aluminum oxide deposition on the copper structures after the providing the wet and dry treatment and before the dry halogen containing etch of remaining barrier film.

19. The method, as recited in 17 , wherein the providing the halogen containing etch, comprises:
providing an etch gas comprising H 2 and a halogen; and
forming the etch gas into a plasma.

20. The method, as recited in claim 17 , wherein the dry plasma sputtering is halogen free.

21. The method, as recited in claim 17 , wherein the dry plasma sputtering has a low halogen contents such that it does not cause Cu corrosion.

22. The method, as recited in claim 17 , further comprising providing a bias of between to 50 to 400 volts, and wherein the forming the plasma comprises providing a RF power of 200 to 1000 watts.

Assignees

• Lam Res Corp

Inventors

• Shen Meihua
• Zhu Ji
• Huang Shuogang
• Zhou Baosuo
• Hoang John
• Sharma Prithu
• Lill Thorsten

Classifications

• H10W20/0633

  using subtractive patterning of the conductive members · CPC title

• H10P50/648

  Anisotropic liquid etching · CPC title

• H10P50/264

  by chemical means · CPC title

• H10P50/262

  by physical means only · CPC title

• H10P50/246

  of Group III-V materials · CPC title