KR-20260066740-A - Etching method and plasma treatment apparatus

Abstract

The present disclosure provides an etching technique capable of improving selectivity. The etching method according to the present disclosure is an etching method performed in a plasma processing apparatus having a chamber, comprising: (a) a process of preparing a substrate on a substrate support disposed within the chamber, wherein the substrate comprises a first film comprising silicon and nitrogen and a second film comprising silicon and oxygen; (b) a process of supplying a processing gas comprising a metal-containing gas into the chamber; and (c) a process of selectively etching the second film with respect to the first film while (b) is being performed, comprising: (c1) a process of generating plasma by setting the power of a source RF signal having a first frequency to a first power and also supplying a first bias signal having a frequency that does not substantially contribute to the generation of plasma to the substrate support at a second power; and (c2) a process of, after (c1), also supplying the first bias signal to the substrate support at a third power higher than the second power.

Inventors

• 다카타 후미야
• 모리키타 신야
• 오이카와 고타
• 니이쿠라 나츠키

Assignees

• 도쿄엘렉트론가부시키가이샤

Dates

Publication Date

20260512

Application Date

20240904

Priority Date

20230908

Claims (20)

1. An etching method performed in a plasma processing apparatus equipped with a chamber, (a) A process of preparing a substrate on a substrate support disposed within the chamber above, wherein the substrate comprises a first film comprising silicon and nitrogen and a second film comprising silicon and oxygen, and (b) a process of supplying a treatment gas containing a metal-containing gas into the chamber, and (c) A process of selectively etching the second film with respect to the first film while the above (b) is being performed, (c1) A process of generating plasma by setting the power of a source RF signal having a first frequency to a first power, and also supplying a first bias signal having a frequency that does not substantially contribute to the generation of plasma to a substrate support at a second power, and (c2) After (c1) above, a process of supplying the first bias signal to the substrate support at a third power higher than the second power. An etching method including
2. In paragraph 1, The above (c2) is an etching method further comprising a process of setting the power of the source RF signal to a fourth power lower than the first power.
3. In paragraph 1, In the above (a), the substrate, when viewed as a planar surface, comprises a plurality of first regions and at least one second region between the first regions, and the first film is disposed in the plurality of first regions, and also comprises a concave portion in the at least one second region, and the second film is disposed in the concave portion. An etching method according to (c) above, wherein the second film is selectively etched with respect to the first film, so that at least a portion of the side of the first film is exposed in the second region.
4. In paragraph 3, In the above (a), the second film is also disposed on the first film, and the substrate includes a mask having a first opening on the second film, and the mask is disposed on the second film such that, when the substrate is viewed as a plane, the first opening overlaps with the concave portion. An etching method according to (c) above, wherein the second film is selectively etched with respect to the first film, so that a portion of the upper surface of the first film is exposed in the plurality of first regions, and also at least a portion of the side surface of the first film is exposed in the second region.
5. In paragraph 4, An etching method according to (a) above, wherein the mask includes a second opening having a larger opening area than the first opening, and the mask is disposed on the second film such that, when viewing the substrate as a plane, the second opening also overlaps with the concave portion, and the number of the concave portions overlapping with the first opening is less than the number of the concave portions overlapping with the second opening.
6. In paragraph 1, The first film is disposed on the second film, and the first film includes an opening that exposes a portion of the second film. An etching method according to (c) above, wherein, in the opening, a portion of the second film is selectively etched with respect to the first film, and a concave portion is formed in the second film.
7. In paragraph 2, The above (c) is an etching method further comprising the process of (c3) between (c1) and (c2), setting the power of the source RF signal to a fifth power equal to or lower than the fourth power to generate plasma, and also supplying the first bias signal to the substrate support at the second power.
8. In paragraph 6, The above (c) is an etching method further comprising the process of (c4) between (c1) and (c3), setting the power of the source RF signal to a sixth power lower than the first power and higher than the fourth power to generate plasma, and also supplying the first bias signal to the substrate support at the second power.
9. In paragraph 2, The above-mentioned fourth power is zero power, an etching method.
10. In Paragraph 7, An etching method in which the above-mentioned fourth power and the above-mentioned fifth power are zero power.
11. In Paragraph 7, An etching method in which the fifth power is lower than the fourth power, and furthermore, the fifth power is zero power.
12. In paragraph 1, An etching method in which the second power is zero power.
13. In paragraph 1, An etching method wherein the first frequency is 60 MHz to 200 MHz.
14. In paragraph 1, An etching method in which the frequency of the first bias signal is 100 kHz to 800 kHz.
15. In paragraph 1, In the above (c1), a second bias RF signal having a second frequency lower than the first frequency is supplied to the substrate support with a seventh power, and An etching method according to (c2), wherein the second bias RF signal is supplied to the substrate support at an eighth power lower than the seventh power.
16. In paragraph 15, An etching method in which the second frequency is 3 MHz to 40 MHz.
17. In any one of paragraphs 1 through 15, An etching method in which the metal-containing gas is a gas containing tungsten-containing gas or molybdenum-containing gas.
18. In Paragraph 17, The above tungsten-containing gas is an etching method containing tungsten fluoride.
19. In any one of paragraphs 1 through 16, The above-mentioned processing gas is an etching method comprising a carbon-containing gas.
20. In Paragraph 18, An etching method in which the carbon-containing gas is a fluorocarbon gas.

Description

Etching method and plasma treatment apparatus An exemplary embodiment of the present disclosure relates to an etching method and a plasma processing apparatus. There is an etching method described in Patent Document 1 as a technique for selectively etching a first region composed of silicon oxide with respect to a second region composed of silicon nitride. Figure 1 is a diagram illustrating an example of the configuration of a plasma processing system. Figure 2 is a diagram illustrating an example of the configuration of a capacitance-coupled plasma processing device. FIG. 3 is a flowchart of an etching method according to one exemplary embodiment. Figure 4 is a drawing illustrating an example of the cross-sectional structure of a substrate (W) prepared in process ST1. FIG. 5 is a diagram illustrating an example of the cross-sectional structure of a substrate (W) after a portion of the silicon oxide film is etched in process ST2. Figure 6 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 7 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 8 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 9 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 10 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 11 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 12 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 13 is a timing chart showing an example of a source RF signal (HF), a bias RF signal (MF), and a bias RF signal (LF) in process ST32. FIG. 14 is a drawing illustrating an example of the cross-sectional structure of a substrate (W) on which process ST3 is performed. FIG. 15 is a drawing illustrating an example of the cross-sectional structure of a substrate (W) on which process ST3 is performed. FIG. 16 is a drawing illustrating an example of a cross-sectional structure of a substrate (W). FIG. 17 is a drawing illustrating an example of the cross-sectional structure of a substrate (W) on which process ST3 is performed. FIG. 18 is a drawing illustrating an example of the cross-sectional structure of a substrate (W) on which process ST3 is performed. Hereinafter, each embodiment of the present disclosure will be described. In one exemplary embodiment, an etching method is provided to be executed in a plasma processing apparatus having a chamber. The etching method comprises: (a) a process of preparing a substrate on a substrate support disposed within the chamber, wherein the substrate comprises a first film comprising silicon and nitrogen and a second film comprising silicon and oxygen; (b) a process of supplying a processing gas comprising a metal-containing gas into the chamber; and (c) a process of selectively etching the second film with respect to the first film while (b) is being executed, comprising: (c1) a process of generating plasma by setting the power of a source RF signal having a first frequency to a first power and also supplying a first bias signal having a frequency that does not substantially contribute to the generation of plasma to the substrate support at a second power; and (c2) a process of supplying the first bias signal to the substrate support at a third power higher than the second power after (c1). In one exemplary embodiment, (a) the substrate, when viewed as a planar substrate, comprises a plurality of first regions and at least one second region between the first regions, and a first film is disposed in the plurality of first regions and also comprises a concave portion in at least one second region, and a second film is disposed in the concave portion, and (c) the second film is selectively etched with respect to the first film so that at least a portion of the side of the first film is exposed in the second region. In one exemplary embodiment, (a) the second film is also disposed on the first film, and the substrate includes a mask having a first opening on the second film, and the mask is disposed on the second film such that the first opening overlaps with the concave portion when the substrate is viewed as a plane, and (c) the second film is selectively etched with respect to the first film so that a portion of the upper surface of the first film is exposed in a plurality of first regions, and also at least a portion of the side surface of the first film is exposed in a second region. In one exemplary embodiment, (a), the mask includes a second opening having a larger opening area than the f