DRY ETCHING METHOD FOR SILICON NITRIDE FILM

• US 20100197143A1
• Filed: 02/02/2010
• Published: 08/05/2010
• Est. Priority Date: 02/03/2009
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Shimizu, Yusuke, Nishimura, Eiichi
• Granted Patent: US 8,679,985 B2
• Time in Patent Office: Days
• US Class Current: 438/734
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

A dry etching method for a silicon nitride film capable of improving throughput is provided. A dry etching method for dry-etching a silicon nitride film 103 includes dry-etching the silicon nitride film 103 without generating plasma by using a processing gas containing at least a hydrogen fluoride gas (HF gas) and a fluorine gas (F₂ gas), with respect to a processing target object 100 including the silicon nitride film 103.

Claims

1. A dry etching method for dry-etching a silicon nitride film, the method comprising:

dry-etching the silicon nitride film without generating plasma by using a processing gas containing at least a hydrogen fluoride gas and a fluorine gas, with respect to a processing target object including the silicon nitride film.

2. A dry etching method for dry-etching a silicon nitride film formed on a silicon oxide film not containing phosphorous, the method comprising:

a first process of dry-etching the silicon nitride film without generating plasma by supplying a processing gas, which contains at least a hydrogen fluoride gas and a fluorine gas, into a chamber until just-etching or almost just-etching of the silicon nitride film is achieved; and

a second process of over-etching the silicon nitride film without generating plasma by changing an atmosphere within the chamber to an atmosphere of a processing gas containing only a hydrogen fluoride gas, after the first process.

3. The dry etching method of claim 2, further comprising:

between the first process and the second process, a process of heat-treating a processing target object including the silicon oxide film and the silicon nitride film by setting a temperature of a stage, on which the processing target object is mounted, to be higher than a temperature of the stage in the first process.

4. The dry etching method of claim 3, wherein a chamber in which the heat treatment is performed is different from the chamber in which the dry etching is performed in the first process and the second process.

5. The dry etching method of claim 2, further comprising:

between the first process and the second process, a process of changing an atmosphere within the chamber to an atmosphere of a nonreactive gas.

6. The dry etching method of claim 2, wherein a material that lowers a boiling point of water is added to the processing gas containing at least the hydrogen fluoride gas and the fluorine gas.

7. The dry etching method of claim 5, wherein in the process of changing the atmosphere within the chamber to the atmosphere of the nonreactive gas, a material that lowers a boiling point of water is added to the nonreactive gas.

8. The dry etching method of claim 3, wherein a material that lowers a boiling point of water is added to the processing gas containing at least the hydrogen fluoride gas and the fluorine gas.

9. The dry etching method of claim 4, wherein a material that lowers a boiling point of water is added to the processing gas containing at least the hydrogen fluoride gas and the fluorine gas.

10. The dry etching method of claim 5, wherein a material that lowers a boiling point of water is added to the processing gas containing at least the hydrogen fluoride gas and the fluorine gas.