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JP-2026076174-A - Apparatus and method for supplying multiple waveform signals during plasma processing

JP2026076174AJP 2026076174 AJP2026076174 AJP 2026076174AJP-2026076174-A

Abstract

[Problem] Embodiments of this disclosure generally relate to systems used in semiconductor device manufacturing processes. [Solution] Embodiments provided herein generally include apparatus and methods for synchronizing and controlling the supply of RF bias voltage signals and pulsed voltage waveforms to one or more electrodes inside a plasma processing chamber. Embodiments of the Disclosure include methods and apparatus for synchronizing a pulsed radio frequency (RF) waveform with a pulsed voltage (PV) waveform so that the pulsed RF waveform is turned on during a first stage of the PV waveform and turned off during a second stage. The first stage of the PV waveform includes a sheath collapse stage. The second stage of the PV waveform includes an ion current stage. [Selection Diagram] Figure 5B

Inventors

  • ロジャーズ， ジェームズ
  • カワサキ， カツマサ

Assignees

  • アプライド マテリアルズ インコーポレイテッド

Dates

Publication Date
20260511
Application Date
20251225
Priority Date
20220809

Claims (20)

  1. A method for plasma processing, Applying a pulsed voltage waveform to one or more electrodes arranged within a substrate support, wherein the pulsed voltage waveform includes a series of voltage pulses each comprising a first stage and a second stage. In order to generate plasma within the processing area of the processing chamber, a pulsed radio frequency (RF) waveform is applied to one or more electrodes, A method comprising synchronizing the pulsed RF waveform with each pulse of the pulsed voltage waveform so that the RF waveform of the pulsed radio frequency (RF) waveform is supplied only for at least a portion of the second stage of each pulse of the pulsed voltage waveform.
  2. The method according to claim 1, wherein the first step includes a sheath collapse step, and the second step includes an ion current step.
  3. The method according to claim 1, wherein the series of voltage pulses are supplied at a frequency of 100 kHz or higher.
  4. The method according to claim 3, wherein the pulsed RF waveform includes a series of RF pulses supplied at a frequency equal to the frequency of the series of voltage pulses.
  5. Applying the pulse voltage waveform to one or more electrodes Applying a first pulse voltage waveform to a first electrode disposed within the substrate support, Applying a second pulse voltage waveform to a second electrode arranged on the substrate support, wherein the second pulse voltage waveform is such that the first pulse voltage waveform and the second pulse voltage waveform each have a first stage and a second stage, The method further includes synchronizing the application of the first and second stages of the first and second pulse voltage waveforms to the first and second electrodes, respectively. The method according to claim 1, further comprising synchronizing the pulse RF waveform with each pulse of the pulse voltage waveform, synchronizing the pulse RF waveform with each pulse of the first pulse voltage waveform, and synchronizing the pulse RF waveform with each pulse of the second pulse voltage waveform.
  6. The method according to claim 5, wherein the first electrode is surrounded by the second electrode.
  7. The method according to claim 1, wherein the RF waveform of the pulsed RF waveform is supplied after a first time delay has elapsed, and the first time delay begins at the end of the first stage of each pulse of the pulsed voltage waveform.
  8. The method according to claim 7, wherein the first time delay has a length between 1% and 20% of the total length of the second stage of the pulse voltage waveform.
  9. The method according to claim 1, wherein the first stage of each pulse in the pulse voltage waveform begins after a second time delay has elapsed, and the start of the second time delay begins at the end of the period during which the RF waveform of the pulse radio frequency (RF) waveform is supplied during at least a portion of the second stage.
  10. The method according to claim 9, wherein the second time delay has a length between 0.1% and 10% of the total length of the second stage of the pulse voltage waveform.
  11. The method according to claim 1, wherein the second step includes a sheath collapse step, and the first step includes an ion current step.
  12. A plasma processing system, A pulse voltage waveform generator connected to the first electrode, A radio frequency waveform generator connected to a second electrode, configured to generate plasma within the processing space of the plasma processing system, An impedance matching circuit connected between the radio frequency waveform generator and the second electrode, The system comprises a controller having a processor configured to execute computer-readable instructions stored in memory, wherein the computer-readable instructions are, The method involves applying a pulse voltage waveform to the first electrode using the pulse voltage waveform generator, wherein the pulse voltage waveform includes a series of voltage pulses each comprising a first stage and a second stage. In order to generate plasma within the processing area of the processing chamber, a pulsed radio frequency waveform is applied to the second electrode by using the radio frequency waveform generator, A plasma processing system that synchronizes a pulsed radio frequency (RF) waveform with each pulse of the pulsed voltage waveform so that the RF waveform of the pulsed RF waveform is supplied only for at least a portion of the second stage of each pulse of the pulsed voltage waveform.
  13. The plasma processing system according to claim 12, wherein the first stage of the pulse voltage waveform includes a sheath collapse stage, and the second stage of the pulse voltage waveform includes an ion current stage.
  14. The plasma processing system according to claim 12, wherein the series of voltage pulses are supplied at a frequency of 100 kHz or higher.
  15. The plasma processing system according to claim 14, wherein the pulsed RF waveform includes a series of RF pulses supplied at a frequency equal to the frequency of the series of voltage pulses.
  16. The plasma processing system according to claim 12, wherein the first electrode and the second electrode are arranged within a substrate support.
  17. The plasma processing system according to claim 16, wherein the first electrode is surrounded by the second electrode.
  18. The plasma processing system according to claim 12, wherein the RF waveform of the pulsed RF waveform is executed after a first time delay has elapsed, and the first time delay begins at the end of the first stage of each pulse of the pulsed voltage waveform.
  19. The plasma processing system according to claim 18, wherein the first time delay has a length between 1% and 20% of the total length of the second stage of the pulse voltage waveform.
  20. The plasma processing system according to claim 12, wherein the second stage of the pulse voltage waveform includes a sheath collapse stage, and the first stage of the pulse voltage waveform includes an ion current stage.

Description

The embodiments of this disclosure generally relate to systems and methods used in semiconductor device manufacturing. More specifically, the embodiments provided herein generally include systems and methods for synchronizing a radio frequency (RF) pulse waveform with a pulse voltage (PV) waveform on one or more electrodes inside a processing chamber. Reliably manufacturing high-aspect-ratio features is one of the key technical challenges for next-generation semiconductor devices. One method for forming high-aspect-ratio features is to use a plasma-assisted etching process (e.g., reactive ion etching (RIE) plasma process) to create high-aspect-ratio openings in the material layer of the substrate (e.g., the dielectric layer). In a typical RIE plasma process, plasma is formed in a processing chamber, and ions from the plasma are accelerated toward the substrate surface, forming openings in the material layer located beneath the mask layer formed on the substrate surface. A typical reactive ion etching (RIE) plasma processing chamber includes a radio frequency (RF) bias generator that supplies an RF voltage to the power electrodes. In capacitively coupled gas discharges, the plasma is generated by using a radio frequency (RF) generator connected to power electrodes located within an electrostatic chuck (ESC) assembly or another part of the processing chamber. Typically, an RF matching network ("RF matching") supplies RF power to a 50Ω apparent load, aligning the RF waveform supplied from the RF generator to minimize reflected power and maximize power supply efficiency. If the load impedance is not properly matched to the source impedance (e.g., the RF generator), some of the forward-supplied RF waveform may be reflected again in the opposite direction along the same transmission line. Many plasma processes also utilize DC voltage pulses to control the plasma sheath placed on the substrate during processing. During operation, the DC voltage pulses switch the generated plasma sheath between a state containing a thick plasma sheath and a state without a plasma sheath. Typically, the DC pulse technique is configured to supply voltage pulses at frequencies above 50 kHz (e.g., frequencies above 400 kHz). The switching of the plasma sheath by the supplied DC pulse voltage waveform causes the plasma load to have different impedance values over time. It has been found that the interaction between the RF waveform and the DC pulse voltage waveform supplied simultaneously during plasma processing can lead to different plasma processing results because the RF matching portion of the RF power supply system cannot adjust the RF matching point to account for the rapidly changing plasma load impedance values over time. Conventional impedance matching components and processes cannot keep up with rapid changes in the magnitude of the plasma load impedance, resulting in the detection of undesirable matching points during matching. Typically, this leads to fluctuations in the amount of RF power actually supplied to the plasma load due to 1) intermodulation distortion (IMD) of the RF signal and 2) undesirable high reflected RF power, which is found in the harmonics of the driving RF frequency. Intermodulation distortion resulting from the interaction between the RF pulse waveform and the DC pulse voltage waveform causes at least the amplitude of the RF signal to change over time. The interaction or intermodulation between the RF pulse waveform and the DC pulse voltage waveform creates further undesirable waveform components at frequencies other than the harmonic frequencies (i.e., integer multiples) of the interacting signals, such as either the RF pulse waveform or the DC pulse waveform. The generation of IMD components in the power supply system reduces the actual forward RF power supplied to the plasma load. At a minimum, rapidly changing plasma load impedance values, resulting from unavoidable differences in the power supply configuration and power supply components of processing chambers, cause undesirable differences in plasma processing results, observed in a single plasma processing chamber, in similarly configured processing chambers on a single processing system, and in similarly configured plasma processing chambers within different plasma processing systems within a semiconductor manufacturing site. Furthermore, the generated IMD components, due to the wide range of frequencies that may occur during plasma processing in the same or different processing chambers, are not readily considered in most power supply systems, thus causing unexpected fluctuations in the power actually supplied to the plasma load during plasma processing. Therefore, in this field, there is a need for plasma processing devices and biasing methods that can solve at least the problems described above. This disclosure generally relates to a method for plasma processing, comprising applying a voltage waveform to electrodes disposed in a substrate sup