Etching method

• US 9,396,962 B2
• Filed: 02/19/2015
• Issued: 07/19/2016
• Est. Priority Date: 02/24/2014
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Kitagaito, Keiji, Katsunuma, Takayuki, Honda, Masanobu
• Primary Examiner(s): DUCLAIR, STEPHANIE P.
• Application Number:
  US14/626,022
• Publication Number:
  US 20150243522A1
• Time in Patent Office: 516 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/31055 the removal being a chemical etching step, e.g. dry etching etching per se H01L21/311
• CPC Class Codes: H01L 21/311 Etching the insulating layers by chemical or physical means H01L21/31058 takes precedence
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/76897 Formation of self-aligned vias or contact plugs, i.e. involving a lithographically uncritical step self-aligned silicidation on field effect transistors H01L29/665

Abstract

An etching method can etch a region formed of silicon oxide. The etching method includes an exposing process (process (a)) of exposing a target object including the region formed of the silicon oxide to plasma of a processing gas containing a fluorocarbon gas, etching the region, and forming a deposit containing fluorocarbon on the region; and an etching process (process (b)) of etching the region with a radical of the fluorocarbon contained in the deposit. Further, in the method, the process (a) and the process (b) are alternately repeated.

Claims

1. An etching method of etching a first region formed of silicon oxide, the etching method comprising:

an exposing process of exposing a target object including the first region and a second region formed of silicon nitride to plasma of a processing gas containing a fluorocarbon gas, etching the first and second regions, and forming a deposit containing fluorocarbon on the first and second regions;

a modified region forming process of forming a modified region of the deposit on the second region by colliding active species generated from the fluorocarbon gas with the second region; and

an etching process of etching the first region with a radical of the fluorocarbon contained in the deposit by exposing the target object to plasma of a gas containing a rare gas,

wherein the exposing process of exposing the target object to the plasma of the processing gas containing the fluorocarbon gas and the etching process of etching the first region with the radical of the fluorocarbon are alternately repeated.

2. The etching method of claim 1,

wherein the fluorocarbon gas is not supplied in the etching process of etching the first region with the radical of the fluorocarbon.

3. The etching method of claim 1,

wherein the exposing process of exposing the target object to the plasma of the processing gas containing the fluorocarbon gas and the etching process of etching the first region with the radical of the fluorocarbon are performed in a capacitively coupled plasma processing apparatus including an upper electrode,

the upper electrode has an electrode plate made of silicon,

the upper electrode is connected to a power supply configured to apply a voltage for attracting positive ions to the electrode plate, and

the voltage is applied to the upper electrode in at least one of the exposing process of exposing the target object to the plasma of the processing gas containing the fluorocarbon gas and the etching process of etching the first region with the radical of the fluorocarbon.