Etching method

Patent metadata

Field	Value
Publication number	US-9779961-B2
Application number	US-201514826569-A
Country	US
Kind code	B2
Filing date	Aug 14, 2015
Priority date	Aug 29, 2014
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

Disclosed is a method for etching a first region including a multi-layer film formed by providing silicon oxide films and silicon nitride films alternately, and a second region having a single silicon oxide film. The etching method includes: providing a processing target object including a mask provided on the first region and the second region within a processing container of a plasma processing apparatus; generating plasma of a first processing gas including a hydrofluorocarbon gas within the processing container that accommodates the processing target object; and generating plasma of a second processing gas including a fluorocarbon gas within the processing container that accommodates the processing target object. The step of generating the plasma of the first processing gas and the step of generating the plasma of the second processing gas are alternately repeated.

First claim

What is claimed is:

1. A method of etching a first region and a second region formed over a substrate, the first region including a multi-layer film of a silicon oxide film and a silicon nitride film laminated in an alternate manner, the second region including a single layer of silicon oxide film, the method comprising:
providing a processing target object including a mask having a predetermined pattern on the first region and the second region within a processing container of a plasma processing apparatus, the mask being configured to etch the first region and the second region simultaneously to form the predetermined pattern on the first region and the second region;
a first generating step including generating plasma of a first processing gas including a hydrofluorocarbon gas within the processing container that accommodates the processing target object;
a second generating step including generating plasma of a second processing gas including a fluorocarbon gas within the processing container that accommodates the processing target object; and
repeating a plurality of times the first generating step and the second generating step in an alternate manner such that a difference between an etching rate of the first region and an etching rate of the second region is reduced.

2. The method of claim 1 , wherein
the first generating step includes setting the etching rate of the first region higher than the etching rate of the second region, and
the second generating step includes setting the etching rate of the second region higher than the etching rate of the first region.

3. The method of claim 2 , wherein
the first generating step includes etching the first region prior to the second region, and
the second generating step includes etching the second region prior to the first region.

4. The method of claim 1 , wherein the fluorocarbon gas includes C 4 F 6 .

5. The method of claim 1 , wherein the first processing gas further includes a nitrogen trifluoride.

6. The method of claim 1 , wherein the first processing gas further includes H 2 gas.

7. The method of claim 1 , wherein the first processing gas includes at least one selected from the group consisting of a carbonyl sulfide gas, a hydrocarbon gas, a boron trichloride gas, and any combination thereof.

8. The method of claim 1 , wherein the mask is formed of amorphous carbon.

9. The method of claim 1 , wherein the first region and the second region have substantially same thickness.

10. The method of claim 1 , wherein
the processing target object further includes an underlayer of polycrystal silicon on the substrate, and
the first region and the second region are formed on the underlayer.

11. The method of claim 1 , wherein
the predetermined pattern includes holes in the first region and in the second region, and
the holes in the first region and the holes in the second region have substantially same depth.

12. The method of claim 1 , wherein the repeating includes repeating the first generating step and the second generating step in an alternate manner until the predetermined pattern of a predetermined depth is obtained both in the first region and in the second region in a same processing batch.

Assignees

• Tokyo Electron Ltd

Inventors

• Saitoh Yusuke
• Nagatomo Yu
• Hishinuma Hayato
• Takayama Wataru
• Tominaga Sho
• Kaneko Yuki

Classifications

• H10P50/242

  of Group IV materials · CPC title

• H10P76/405

  characterised by their composition, e.g. multilayer masks · CPC title

• H10P50/694

  characterised by their behaviour during the process, e.g. soluble masks or redeposited masks · CPC title

• H10P50/73

  using masks for insulating materials · CPC title

• H10P50/283 Primary

  by chemical means · CPC title