Search

US-12628587-B2 - Etching method and etching apparatus

US12628587B2US 12628587 B2US12628587 B2US 12628587B2US-12628587-B2

Abstract

An etching method according to one embodiment of the present disclosure includes step (a), step (b), step (c), step (d), and step (e). Step (a) provides a substrate that has a silicon-containing film which does not include oxygen and nitrogen, and a mask formed on the silicon-containing film. Step (b) etches the silicon-containing film with plasma generated from a first processing gas that includes a halogen-containing gas to form a recess portion. Step (c) forms an oxide film in the recess portion with plasma generated from a second processing gas that includes an oxygen-containing gas and a gas including carbon, hydrogen, and fluorine. Step (d) further etches the silicon-containing film with the plasma generated from the first processing gas after step (c). Step (e) repeatedly executes step (c) and step (d) a preset number of times.

Inventors

  • Fumiya TAKATA
  • Yusuke Takino

Assignees

  • TOKYO ELECTRON LIMITED

Dates

Publication Date
20260512
Application Date
20220926
Priority Date
20210927

Claims (19)

  1. 1 . An etching apparatus comprising: a plasma processing chamber providing a processing space; a substrate support provided inside the plasma processing chamber and configured to support a substrate having a silicon-containing film that does not include oxygen and nitrogen; a gas supply configured to supply a processing gas into the plasma processing chamber; and a controller configured to control the plasma processing chamber, the substrate support and the gas supply to execute (a) providing the substrate that has a silicon-containing film that does not include oxygen and nitrogen, and a mask formed on the silicon-containing film, (b) etching the silicon-containing film with plasma generated from a first processing gas that includes a halogen-containing gas to form a recess portion, (c) forming an oxide film in the recess portion with plasma generated from a second processing gas that includes an oxygen-containing gas and a gas including carbon, hydrogen, and fluorine, (d) further etching the silicon-containing film with the plasma generated from the first processing gas after (c), and (e) repeatedly executing (c) and (d) a predetermined number of times, wherein in (e), a film thickness of the oxide film to be formed is changed by changing a flow ratio of the gas including carbon, hydrogen, and fluorine and the oxygen containing gas in the second processing gas as the processing condition, and wherein the predetermined number of times is at least n times or more (n is a natural number of 2 or more, in (c) up to an (n−1) th time, the flow ratio of the gas including carbon, hydrogen, and fluorine to the oxygen-containing gas is set to a maximum value, and in (c) of an n th time and thereafter, the thickness of the oxide film to be formed is changed by changing the flow ratio to a value lower than the maximum value.
  2. 2 . The etching apparatus according to claim 1 , wherein the flow ratio of the gas including carbon, hydrogen, and fluorine to the oxygen-containing gas is 0.3 or less.
  3. 3 . An etching apparatus comprising: a plasma processing chamber providing a processing space; a substrate support provided inside the plasma processing chamber and configured to support a substrate having a silicon-containing film that does not include oxygen and nitrogen; a gas supply configured to supply a processing gas into the plasma processing chamber; and a controller configured to control the plasma processing chamber, the substrate support and the gas supply to execute (a) providing the substrate that has a silicon-containing film that does not include oxygen and nitrogen, and a mask formed on the silicon-containing film, (b) etching the silicon-containing film with plasma generated from a first processing gas that includes a halogen-containing gas to form a recess portion, (c) forming an oxide film in the recess portion with plasma generated from a second processing gas that includes an oxygen-containing gas and a gas including carbon, hydrogen, and fluorine, (d) further etching the silicon-containing film with the plasma generated from the first processing gas after (c), and (e) repeatedly executing (c) and (d) a predetermined number of times, wherein in (e), a film thickness of the oxide film to be formed is changed by changing a ratio of a processing time of (d) and a processing time of (c) as the processing condition, and wherein the predetermined number of times is at least n times or more (n is a natural number of 2 or more, in (c) and (d) up to an (n−1) th time, the ratio of the processing time of (d) to the processing time of (c) is set to a minimum value, and in (c) and (d) of an n th time and thereafter, the thickness of the oxide film to be formed is changed by changing the ratio to a value higher than the minimum value.
  4. 4 . The etching apparatus according to claim 1 , wherein the halogen-containing gas is at least one member selected from the group consisting of a chlorine-containing gas and a bromine-containing gas.
  5. 5 . The etching apparatus according to claim 1 , wherein the halogen-containing gas is at least one chlorine-containing gas selected from the group consisting of Cl 2 , SiCl 4 , and HCl.
  6. 6 . The etching apparatus according to claim 1 , wherein the halogen-containing gas is at least one bromine-containing gas selected from the group consisting of HBr and Br 2 .
  7. 7 . The etching apparatus according to claim 1 , wherein the oxygen-containing gas is at least one oxygen-containing gas selected from the group consisting of O 2 , CO, CO 2 , and SO 2 .
  8. 8 . The etching apparatus according to claim 1 , wherein the gas including carbon, hydrogen, and fluorine is at least one type selected from the group of a mixed gas including a C x H y F z (x, y, and z are natural numbers) gas, a C x F y (x and y are natural numbers) gas, and a H 2 gas.
  9. 9 . The etching apparatus according to claim 1 , wherein the gas including carbon, hydrogen, and fluorine is at least one type selected from the group consisting of CH 3 F, CH 2 F 2 , and CHF 3 .
  10. 10 . The etching apparatus according to claim 1 , wherein the gas including carbon, hydrogen, and fluorine is a CF 4 gas and a H 2 gas.
  11. 11 . The etching apparatus according to claim 3 , wherein the ratio of the processing time of (d) to the processing time of (c) is 0.5 or more and 5.0 or less.
  12. 12 . The etching apparatus according to claim 1 , wherein the value lower than the maximum value is less than 0.3.
  13. 13 . The etching apparatus according to claim 3 , wherein the halogen-containing gas is at least one member selected from the group consisting of a chlorine-containing gas and a bromine-containing gas.
  14. 14 . The etching apparatus according to claim 3 , wherein the halogen-containing gas is at least one chlorine-containing gas selected from the group consisting of Ck, SiCl 4 , and HCl.
  15. 15 . The etching apparatus according to claim 3 , wherein the halogen-containing gas is at least one bromine-containing gas selected from the group consisting of HBr and Br 2 .
  16. 16 . The etching apparatus according to claim 3 , wherein the oxygen-containing gas is at least one oxygen-containing gas selected from the group consisting of O 2 , CO, CO 2 , and SO 2 .
  17. 17 . The etching apparatus according to claim 3 , wherein the gas including carbon, hydrogen, and fluorine is at least one type selected from the group of a mixed gas including a C x H y F z (x, y, and z are natural numbers) gas, a C x F y (x and y are natural numbers) gas, and a H 2 gas.
  18. 18 . The etching apparatus according to claim 3 , wherein the gas including carbon, hydrogen, and fluorine is at least one type selected from the group consisting of CH 3 F, CH 2 F 2 , and CHF 3 .
  19. 19 . The etching apparatus according to claim 3 , wherein the gas including carbon, hydrogen, and fluorine is a CF 4 gas and a H 2 gas.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on and claims priority from Japanese Patent Application No. 2021-156416, filed on Sep. 27, 2021 with the Japan Patent Office, the disclosure of which are incorporated herein in its entirety by reference. TECHNICAL FIELD The present disclosure relates to an etching method and an etching apparatus. BACKGROUND Conventionally, there is a technique of etching a silicon film of a substrate in which a silicon film and a pattern mask are stacked in order from a bottom with plasma generated from a halogen-containing gas (see Japanese Patent Laid-open Publication No. 2015-037091). SUMMARY An etching method according to one aspect of the present disclosure includes step (a), step (b), step (c), step (d), and step (e). Step (a) is a step of providing a substrate that has a silicon-containing film which does not include oxygen and nitrogen, and a mask formed on the silicon-containing film. Step (b) is a step of etching the silicon-containing film with plasma generated from a first processing gas that includes a halogen-containing gas to form a recess portion. Step (c) is a step of forming an oxide film in the recess portion with plasma generated from a second processing gas that includes an oxygen-containing gas and a gas including carbon, hydrogen, and fluorine. Step (d) is a step of further etching the silicon-containing film with the plasma generated from the first processing gas after step (c). Step (e) is a step of repeatedly executing step (c) and step (d) a preset number of times. In the etching method, in step (e), a thickness of the oxide film to be formed is changed by changing a processing condition of at least one of step (c) and step (d). The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flowchart illustrating an example of a flow of an etching method according to an embodiment. FIG. 2A is a view illustrating an example of a state of a substrate in each step of the etching method according to the embodiment. FIG. 2B is a view illustrating an example of the state of the substrate in each step of the etching method according to the embodiment. FIG. 2C is a view illustrating an example of the state of the substrate in each step of the etching method according to the embodiment. FIG. 2D is a view illustrating an example of the state of the substrate in each step of the etching method according to the embodiment. FIG. 2E is a view illustrating an example of the state of the substrate in each step of the etching method according to the embodiment. FIG. 3 is a view for explaining an example of an oxide film forming step. FIG. 4 is a view for explaining an example of the oxide film forming step. FIG. 5 is a view for explaining an example of the oxide film forming step. FIG. 6 is a diagram illustrating an example of conditions used in the etching method according to the embodiment. FIG. 7 is a view illustrating an example of an etching apparatus according to an embodiment. DETAILED DESCRIPTION In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made without departing from the spirit or scope of the subject matter presented here. Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. The disclosed technology is not limited to the following embodiments. Hereinafter, in the description of the embodiments, when describing a direction of a pattern formed on a substrate, a direction substantially perpendicular to a substrate surface will be referred to as a thickness direction or a vertical direction. Further, a direction substantially parallel to the surface of the substrate will be referred to as a lateral direction. In a case where the substrate is substantially disk-shaped, a direction parallel to the substrate surface from a center of the disk toward a circumference will also be referred to as a radial direction. In the following description, the term “pattern” refers to an overall shape formed on the substrate. The pattern refers to an entirety from a plurality of shapes by a hole, a trench, a line-and-space and a mask formed on the substrate. Further, the term “recess portion” refers to a portion having a shape recessed in the thickness direction of the substrate in the pattern formed on the substrate. Further, the recess portion has a “sidewall” that is an inner peripheral surface of a recessed shape, a “bottom portion” that is a bottom portion of the recessed shape, and a