Etching method for substrate to be processed and plasma-etching device

• US 9,721,803 B2
• Filed: 04/10/2013
• Issued: 08/01/2017
• Est. Priority Date: 05/08/2012
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Takaba, Hiroyuki
• Primary Examiner(s): DUCLAIR, STEPHANIE P.
• Application Number:
  US14/390,217
• Publication Number:
  US 20150118858A1
• Time in Patent Office: 1,574 Days
• Field of Search: None
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01J 37/32926 Software, data control or modelling
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/32137 of silicon-containing layers
• CPC Class Codes: H01L 21/67069 for drying etching

Abstract

In one embodiment of the present invention, an etching method for a substrate to be processed comprises: (a1) a step in which etchant gas is supplied into a processing container than accommodates a substrate to be processed; (b1) a step in which the inside of the processing container is evacuated; (c1) a step in which a noble gas is supplied into the processing container; and (d1) a step in which microwaves are supplied into the processing container so as to excite the plasma of the noble gas inside the processing container. The sequential process including the step of supplying the etchant of supplying the etchant gas, the evacuating step, the step of supplying the noble gas, and the step of exciting the plasma of the noble gas may be repeated.

Claims

1. A method of etching a substrate to be processed, the method comprising:

supplying an etchant gas including Cl₂ gas into a processing container that accommodates the substrate including polycrystalline silicon, thereby allowing the etchant gas to be chemically adsorbed on a surface of the substrate;

after supplying the etchant gas, evacuating the inside of the processing container where the substrate is accommodated;

after evacuating the processing container, supplying a noble gas into the processing container where the substrate is accommodated; and

after supplying the noble gas, generating heat by exciting plasma of the noble gas within the processing container where the substrate is accommodated after the etchant gas is chemically adsorbed on the surface of the substrate by supplying microwaves through a dielectric window into the processing container to activate the noble gas without (i) supplying an RF bias power to a stage supporting the substrate within the processing container and (ii) changing a temperature of the substrate,

wherein atoms of the substrate that form bonds with atoms or molecules of the etchant gas are separated from a surface of the substrate by the heat generated from the activating of the noble gas without cutting the bonds formed between the atoms of the substrate and the atoms or molecules of the etchant gas.

2. The method of claim 1, wherein a series of processes including the supplying of the etchant gas, the evacuating, the supplying of the noble gas, and the exciting of the plasma of the noble gas is repeated.

3. The method of claim 1, wherein a microwave generator supplies the microwaves, wherein the microwaves are further supplied, to the stage, through an antenna containing a dielectric plate.

4. The method of claim 1, wherein, in the activating, a power of the microwave is 1000 W.

5. The method of claim 1, wherein a processing time of the activating is 30 sec or more.

6. A method of etching a substrate to be processed, the method comprising:

supplying an etchant gas including CH₃F gas into a processing container that accommodates the substrate including polycrystalline silicon and silicon nitride, thereby allowing the etchant gas to be chemically adsorbed on a surface of the substrate;

supplying a noble gas into a processing container where the substrate is accommodated;

generating heat by exciting plasma of the noble gas within the processing container where the substrate is accommodated after the etchant gas is chemically adsorbed on the surface of the substrate by supplying microwaves through a dielectric window into the processing container to activate the noble gas without (i) supplying an RF bias power to a stage supporting the substrate within the processing container and (ii) changing a temperature of the substrate,

wherein such that atoms of the substrate that form bonds with atoms or molecules of the etchant gas are separated from a surface of the substrate by the heat generated from the activating of the noble gas without cutting the bonds formed between the atoms of the substrate and the atoms or molecules of the etchant gas; and

alternately increasing and decreasing a supply amount of the etchant gas in relation to an inside of the processing container in which the substrate is accommodated, in a period of exciting the plasma.

7. The method of claim 6, wherein in the alternately increasing and decreasing the supply amount of the etchant gas, supply of the etchant gas and supply stop of the etchant gas are alternately switched.