CN-122029635-A - Plasma processing apparatus and etching method

CN122029635ACN 122029635 ACN122029635 ACN 122029635ACN-122029635-A

Abstract

The plasma processing apparatus includes a chamber, a substrate supporting portion, a gas supplying portion, a first high-frequency power source, a voltage pulse source, a second high-frequency power source, and a control portion. The substrate supporting portion is disposed in the chamber and is capable of supporting a substrate. The control unit is capable of controlling the gas supply unit to supply the process gas into the chamber and the first high-frequency power supply to plasmatize the process gas in the chamber, and the voltage pulse supply unit to supply the voltage pulse to the substrate support unit and the second high-frequency power supply unit to supply the second high-frequency power to the substrate support unit in superposition with the voltage pulse.

Inventors

SATO KAZUYUKI
HINO YUTAKA
YAMADA KAZUYA
C. THOMAS
Takata Masahiko

Assignees

东京毅力科创株式会社

Dates

Publication Date: 20260512
Application Date: 20250820
Priority Date: 20240903

Claims (13)

1. A plasma processing apparatus, comprising: A chamber; A substrate supporting portion disposed in the chamber and configured to support a substrate; A gas supply unit configured to supply a process gas into the chamber; a first high-frequency power supply capable of supplying a first high-frequency electric power for plasmatizing a process gas in the chamber; A voltage pulse source capable of supplying a voltage pulse obtained by pulsing a dc voltage to the substrate support section; a second high-frequency power supply capable of supplying a second high-frequency electric power to the substrate supporting portion, and And a control unit configured to supply the process gas from the gas supply unit into the chamber, supply a first high-frequency electric power from the first high-frequency power source to plasmatize the process gas in the chamber, supply the voltage pulse from the voltage pulse source to the substrate support unit, and supply the second high-frequency electric power from the second high-frequency power source to the substrate support unit in superposition with the voltage pulse when etching the substrate.
2. The plasma processing apparatus according to claim 1, wherein: The voltage pulse source is capable of changing the duty ratio of the voltage pulse by periodically turning on and off a direct current voltage of a negative polarity and changing the ratio of the periods of on and off in 1 cycle, The control unit may control the duty ratio of the voltage pulse to 10% -80%.
3. The plasma processing apparatus according to claim 2, wherein: The control unit may control the duty ratio of the voltage pulse to 10% -20%.
4. The plasma processing apparatus according to claim 2, wherein: The substrate is provided with a target film as an etching target on a base layer, The control section can control so that the duty ratio of the voltage pulse is smaller as the bottom of the hole formed in the object film by etching is closer to the base layer.
5. The plasma processing apparatus according to claim 1, wherein: the voltage pulse source is capable of periodically switching on and off a dc voltage of negative polarity to supply the voltage pulse, The second high-frequency power supply is capable of supplying the second high-frequency electric power not during the on period but during the off period.
6. The plasma processing apparatus according to claim 1, wherein: The substrate is provided with a target film as an etching target on a base layer, The control unit may perform the control when the bottom of the hole formed in the target film by etching reaches the base layer.
7. The plasma processing apparatus according to claim 1, wherein: the substrate has a fin structure having a plurality of fins on a base layer, a gate material deposited on the fin structure, and a mask on the gate material, The control portion is capable of performing the control while etching the gate material deposited between the plurality of fins of the substrate until the base layer is exposed.
8. The plasma processing apparatus according to claim 1, wherein: The voltage pulse source can supply voltage pulses with the frequency of 100 kHz-1200 kHz.
9. The plasma processing apparatus according to claim 7, wherein: the gate material is polysilicon.
10. The plasma processing apparatus according to claim 7, wherein: The base layer is a silicon oxide film.
11. The plasma processing apparatus according to claim 1, wherein: the control section is capable of controlling a period, a duty ratio, and an amplitude of the voltage pulse and an amplitude of the second high-frequency electric power in etching of the substrate.
12. The plasma processing apparatus according to claim 1, wherein: The substrate is provided with a target film as an etching target on a base layer, The control section is capable of controlling the period, duty ratio and amplitude of the bias DC signal and the amplitude of the bias RF signal so that a peak on a high energy side and a peak on a low energy side of an energy distribution of ions incident to the substrate are higher before a bottom of a hole formed in the object film by etching reaches the base layer, and when the bottom of the hole reaches the base layer, the peak on the low energy side is higher and a range of energy generating the peak on the low energy side is widened.
13. An etching method for a plasma processing apparatus, comprising: the plasma processing apparatus includes: A chamber; A substrate supporting portion disposed in the chamber and configured to support a substrate; A gas supply unit configured to supply a process gas into the chamber; a first high-frequency power supply capable of supplying a first high-frequency electric power for plasmatizing a process gas in the chamber; A voltage pulse source capable of supplying a voltage pulse obtained by pulsing a DC voltage to the substrate support portion, and A second high-frequency power supply capable of supplying a second high-frequency electric power to the substrate supporting portion, The etching method comprises the following steps: When etching the substrate, the process gas is supplied from the gas supply unit into the chamber, a first high-frequency electric power is supplied from the first high-frequency power source, the process gas in the chamber is made into plasma, the voltage pulse is supplied from the voltage pulse source to the substrate support unit, and the second high-frequency electric power is supplied from the second high-frequency power source to the substrate support unit in superposition with the voltage pulse.

Description

Plasma processing apparatus and etching method Technical Field The present invention relates to a plasma processing apparatus and an etching method. Background Patent document 1 below discloses a plasma processing apparatus comprising a chamber, a first matching circuit coupled to the chamber, a second matching circuit coupled to the chamber, a first RF generating section coupled to the first matching circuit and capable of generating a first RF pulse signal including a plurality of pulse periods, each of the plurality of pulse periods including a first period, a second period, and a third period, the first RF pulse signal having a first power level during the first period, a second power level during the second period, and a third power level during the third period, the first period being 30 μs or less, a second RF generating section coupled to the second matching circuit and capable of generating a second RF pulse signal including the plurality of pulse periods, the second RF pulse signal having a frequency lower than that of the first RF pulse signal, the second RF pulse signal having a fourth power level during the first period, a second period, and a third period, the third RF pulse signal having a third power level during the second period, and a third pulse signal having a frequency lower than that of the first pulse signal, the third RF pulse signal having a third pulse signal during the second period, and a third pulse signal having a frequency lower than that of the first pulse signal, the third pulse signal having a third pulse signal during the third period, the second RF pulse signal having the third pulse signal and the third pulse signal having a frequency lower than that of the first pulse signal. Prior art literature Patent literature Patent document 1 Japanese patent laid-open No. 2022-048032 Disclosure of Invention Technical problem to be solved by the invention The invention provides a technology for reducing residues. Means for solving the technical problems The plasma processing apparatus according to an aspect of the present invention includes a chamber, a substrate supporting portion, a gas supplying portion, a first high-frequency power source, a voltage pulse source, a second high-frequency power source, and a control portion. The substrate supporting portion is disposed in the chamber and is capable of supporting a substrate. The gas supply unit can supply a process gas into the chamber. The first high-frequency power supply is capable of supplying first high-frequency electric power for plasmatizing a process gas in the chamber. The voltage pulse source can supply a voltage pulse obtained by pulsing a dc voltage to the substrate support section. The second high-frequency power supply is capable of supplying second high-frequency electric power to the substrate supporting portion. The control unit is capable of controlling the gas supply unit to supply the process gas into the chamber and the first high-frequency power supply to plasmatize the process gas in the chamber, and the voltage pulse supply unit to supply the voltage pulse to the substrate support unit and the second high-frequency power supply unit to supply the second high-frequency power to the substrate support unit in superposition with the voltage pulse. Effects of the invention By adopting the invention, residues can be reduced. Drawings Fig. 1 is a diagram for explaining a configuration example of an inductively coupled plasma processing apparatus. Fig. 2A is a diagram showing an example of etching of the substrate W according to the first embodiment. Fig. 2B is a diagram showing an example of etching of the substrate W according to the first embodiment. Fig. 3A is a diagram showing an example of etching of the substrate W according to the first embodiment. Fig. 3B is a diagram showing an example of etching of the substrate W according to the first embodiment. Fig. 4A is a diagram showing an example of a potential change of the substrate W in the etching method of the first reference example. Fig. 4B is a diagram schematically showing the movement of ions and radicals in the plasma in the etching method of the first reference example. Fig. 4C is a diagram showing an example of the energy distribution of ions in the etching method of the first reference example. Fig. 5A is a diagram showing an example of a potential change of the substrate W in the etching method of the second reference example. Fig. 5B is a diagram schematically showing the movement of ions and radicals in the plasma in the etching method of the second reference example. Fig. 5C is a diagram showing an example of the energy distribution of ions in the etching method of the second reference example. Fig. 6 is a diagram showing an example of residues remaining on the substrate after etching according to the first embodiment. Fig. 7A is a diagram showing an example of a potential change of the substrate W in the etching method according to the first