Method for plasma etching of high-K dielectric materials

• US 20040007561A1
• Filed: 07/12/2002
• Published: 01/15/2004
• Est. Priority Date: 07/12/2002
• Status: Abandoned Application

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Kumar, Ajay, Nallan, Padmapani, Jin, Guangxiang
• Application Number:
  US10/194,566
• Publication Number:
  US 20040007561A1
• Time in Patent Office: Days
• US Class Current: 216/67
• CPC Class Codes: H01L 21/31122 of layers not containing Si, e.g. PZT, Al2O3

Abstract

A method for etching a high K dielectric material comprises etching in a first plasma comprising a halogen containing gas (e.g., chlorine) and a reducing gas (e.g., carbon monoxide) and removing post-etch residue in a second plasma comprising a residue cleaning gas (e.g., oxygen or a mixture of oxygen and nitrogen).

Claims

1. A method for etching in an etch reactor a substrate comprising a dielectric material having a dielectric constant that is greater than 4, comprising:

etching the dielectric material in a first plasma comprising a halogen containing gas and a reducing gas where said etching step produces a residue; and

cleaning the substrate using a second plasma comprising a residue cleaning gas to remove the residue from the substrate.

2. The method of claim 1 wherein said dielectric material is at least one of HfO₂, ZrO₂, Al₂O₃, BST, PZT, ZrSiO₂, HfSiO₂, HfSiON, and TaO₂.

3. The method of claim 1 wherein said dielectric material is HfO₂.

4. The method of claim 1 wherein the etching step and the cleaning step are performed sequentially in the same etch reactor.

5. The method of claim 1 wherein the halogen containing gas comprises a chlorine containing gas, the reducing gas comprises a carbon monoxide containing gas, and the residue cleaning gas comprises oxygen.

6. The method of claim 5 wherein the chlorine containing gas is Cl₂, the reducing gas is CO, and the residue cleaning gas is O₂ or a mixture of O₂ with N₂ or a mixture of O₂ with N₂ and an inert gas such as He.

7. The method of claim 6 wherein the exposing step further comprises a step of:

supplying between 2 to 100 sccm of O₂;

supplying between 0 to 20 sccm of N₂, and

maintaining in the etch reactor a gas pressure between 2 and 100 mTorr.

8. A method for etching comprising an etch step and a residue removal step that are performed in the same reactor to etch a workpiece comprising a dielectric material having a dielectric constant that is greater than 4, comprising:

during the etch step, supplying 20 to 300 sccm of Cl₂ and 2 to 200 sccm of CO, maintaining in the reactor a gas pressure between 2 and 100 mTorr, applying a bias power to a cathode electrode between 0 and 300 Watt, and applying power to an inductively coupled antenna between 200 and 2500 Watt;

during the residue removal step, supplying 20 to 100 sccm of O₂ and 0 to 20 sccm of N₂, maintaining in the reactor a gas pressure between 2 to 100 mTorr, applying a bias power to a cathode electrode between 0 and 10 W, and applying power to an inductively coupled antenna between 200 and 2500 W; and

maintaining the workpiece at a temperature between 0 and 500 degrees Celsius.

9. A computer-readable medium containing software that when executed by a computer causes an etch reactor to plasma etch a dielectric material having a dielectric constant that is greater than 4 using a method comprising:

etching the dielectric material in a first plasma comprising a halogen containing gas and a reducing gas where said etching step produces a residue; and

cleaning the substrate using a second plasma comprising a residue cleaning gas to remove the residue from the substrate.

10. The computer-readable medium of claim 9 wherein said dielectric material is at least one of HfO₂, ZrO₂, Al₂O₃, BST, PZT, ZrSiO₂, HfSiO₂, HfSiON, and TaO₂.

11. The computer-readable medium of claim 9 wherein said dielectric material is HfO₂.

12. The computer-readable medium of claim 9 wherein the etching step and the cleaning step are performed sequentially in the same etch reactor.

13. The computer-readable medium of claim 9 wherein the halogen containing gas comprises a chlorine containing gas, the reducing gas comprises a carbon monoxide containing gas, and the residue cleaning gas comprises oxygen.

14. The computer-readable medium of claim 13 wherein the chlorine containing gas is Cl₂, the reducing gas is CO, and the residue cleaning gas is O₂ or a mixture of O₂ with N₂ or a mixture of O₂ with N₂ and an inert gas such as He.

15. The computer-readable medium of claim 14 wherein the exposing step further comprises a step of:

supplying between 20 to 100 sccm of O₂,

supplying between 0 to 20 sccm of N₂, and

maintaining in the etch reactor a gas pressure between 2 and 100 mTorr.