Method to etch non-volatile metal materials

Patent metadata

Field	Value
Publication number	US-9257638-B2
Application number	US-201414325190-A
Country	US
Kind code	B2
Filing date	Jul 7, 2014
Priority date	Mar 27, 2014
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

A method for etching a stack with an Ru containing layer disposed below a hardmask and above a magnetic tunnel junction (MTJ) stack with pinned layer is provided. The hardmask is etched with a dry etch. The Ru containing layer is etched, where the etching uses hypochlorite and/or O 3 based chemistries. The MTJ stack is etched. The MTJ stack is capped with dielectric materials. The pinned layer is etched following the MTJ capping.

First claim

What is claimed is:

1. A method of etching a stack with an Ru containing layer disposed below a hardmask and above a magnetic tunnel junction (MTJ) stack with a pinned layer, comprising:
etching the hardmask with a dry etch;
etching the Ru containing layer wherein the etching uses hypochlorite and/or O 3 based chemistries;
etching the MTJ stack;
capping the MTJ stack with dielectric materials; and etching the pinned layer following the MTJ capping;
wherein the MTJ etch uses a low bias sputter of a plasma formed from an inert gas instead of a chemical etchant gas.

2. The method, as recited in claim 1 , wherein the low bias sputter provides a bias of 10 to 500 volts.

3. The method, as recited in claim 2 , wherein the etching the Ru containing layer provides a wet etch.

4. The method, as recited in claim 3 , wherein the MTJ stack comprises at least one layer of CoFe and at least one layer of MgO.

5. The method, as recited in claim 4 , wherein the pinned layer comprises at least one layer of PtMn.

6. The method, as recited in claim 5 , wherein the etching the hardmask, etching the Ru containing layer, etching the MTJ layer, capping the MTJ layer, and etching the pinned layer are performed in a single plasma processing chamber.

7. The method, as recited in claim 6 , wherein the etching the MTJ stack uses an inert bombardment gas, which provides a physical bombardment without a chemical etchant gas.

8. The method, as recited in claim 7 , wherein the dielectric material of the capping is a silicon-based dielectric material.

9. The method, as recited in claim 1 , wherein the etching the Ru containing layer provides a wet etch.

10. The method, as recited in claim 1 , wherein the MTJ stack comprises at least one layer of CoFe and at least one layer of MgO.

11. The method, as recited in claim 1 , wherein the pinned layer comprises at least one layer of PtMn.

12. The method, as recited in claim 1 , wherein the etching the hardmask, etching the Ru containing layer, etching the MTJ layer, capping the MTJ layer, and etching the pinned layer are performed in a single plasma processing chamber.

13. The method, as recited in claim 1 , wherein the etching the MTJ stack uses an inert bombardment gas, which provides a physical bombardment without a chemical etchant gas.

14. The method, as recited in claim 1 , wherein the dielectric material of the capping is a silicon-based dielectric material.

15. A method of etching a stack comprising a hard mask over a Ru containing layer, over a magnetic tunnel junction (MTJ) stack over a pinned layer, comprising:
etching the hardmask, Ru containing layer, and MTJ stack; sealing the MTJ stack; and
etching the pinned layer;
wherein the etching the MTJ stack uses a low bias sputter of a plasma formed from an inert gas instead of a chemical etchant gas, wherein the low bias sputter provides a bias of 10 to 500 volts.

16. The method, as recited in claim 15 , wherein the MTJ stack comprises at least one layer of CoFe and at least one layer of MgO.

17. The method, as recited in claim 15 , wherein the sealing the MTJ stack seals the MTJ stack with a silicon-based dielectric material.

18. A method of etching a stack with a pinned layer disposed below a MTJ stack, disposed below an Ru containing layer, disposed below a hardmask layer, comprising:
etching the hardmask with a dry etch;
etching the Ru containing layer;
etching the MTJ stack;
capping the MTJ stack with dielectric materials; and
etching the pinned layer with chemistries selective to noble metals, comprising SOCl 2 /pyridine mixtures, HBr/DMSO mixtures, or a mixture of CCl 4 with at least one of DMSO, acetonitrile, benzonitrile, or dimethylformamide (DMF).

Assignees

• Lam Res Corp

Inventors

• Tan Samantha S H
• Yang Wenbing
• Shen Meihua
• Janek Richard P
• Marks Jeffrey
• Singh Harmeet
• Lill Thorsten

Classifications

• H10P14/3426

  Oxides · CPC title

• H01L27/228

  Electricity · mapped topic

• H01L43/02

  Electricity · mapped topic

• H01L43/12 Primary

  Electricity · mapped topic

• H01L43/10

  Electricity · mapped topic