Pulse voltage waveform biasing of plasma

Abstract

Embodiments of this disclosure include apparatus (e.g., a plasma processing system) and methods for plasma processing of a substrate in a processing chamber. Some embodiments relate to a method for waveform generation, which typically includes transmitting a radio frequency (RF) waveform at a frequency for a first time period using an RF generator, and subsequently stopping the transmission of the RF waveform for a second time period, and transmitting a pulsed voltage waveform at a first voltage for at least a portion of a third time period using a pulser, wherein the transmission of the pulsed voltage waveform overlaps with the transmission of the RF waveform during a portion of the second time period.

Description

Technical Field

[0001] The embodiments described herein generally relate to systems and methods used in the manufacture of semiconductor devices. More specifically, embodiments of this disclosure relate to plasma processing systems for processing substrates. Background Technology

[0002] Reliably generating high aspect ratio features is one of the key technological challenges for next-generation semiconductor devices. One method for forming high aspect ratio features uses plasma-assisted etching processes, such as reactive ion etching (RIE) plasma processes, to form high aspect ratio openings in a material layer (such as a dielectric layer) of a substrate. In a typical RIE plasma process, plasma is generated in a processing chamber, and ions from the plasma are accelerated toward the substrate surface to form openings in a material layer beneath a mask layer formed on the substrate surface.

[0003] As technology nodes advance towards 2 nanometers (nm), the fabrication of smaller features with larger aspect ratios requires atomic precision in plasma processing. For etching processes where plasma ions play a dominant role, ion energy control has always posed a challenge to the development of reliable and repeatable device formation processes in the semiconductor industry. In typical plasma-assisted etching processes, a substrate is positioned on a substrate support within a processing chamber. Plasma is formed above the substrate using a radio frequency (RF) generator coupled to electrodes placed on or within the plasma processing chamber, and ions are accelerated from the plasma towards the substrate across a plasma sheath. Furthermore, RF substrate biasing methods, which require a separate RF bias source in addition to the RF generator used to initiate and sustain the plasma in the processing chamber, are no longer ideally suited for controlling the plasma sheath properties to achieve the desired plasma processing results that would allow for the formation of these smaller device feature sizes. Conventional RF generators and RF biasing methods utilize sinusoidal RF waveforms to excite the plasma and form a plasma sheath. Due to the sinusoidal shape of the RF waveform and the limitations imposed by the available sinusoidal waveform characteristics, RF biasing methods cannot adjust the ion energy during processing, often resulting in undesirable and inconsistent processing outcomes.

[0004] Therefore, there is a need in the field for a plasma-assisted process to solve the above problems. Summary of the Invention

[0005] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and those specifically pointed out in the claims. The following description and figures illustrate certain illustrative features of one or more aspects in detail. However, these features only indicate a few of the many ways in which the principles of each aspect can be employed.

[0006] Embodiments of this disclosure provide a waveform generation method. The method typically includes transmitting a radio frequency (RF) waveform at a frequency during a first time period using an RF generator, and subsequently stopping the transmission of the RF waveform during a second time period; and transmitting a pulsed voltage waveform at a first voltage during at least a portion of a third time period using a pulser, wherein the transmission of the pulsed voltage waveform overlaps with the transmission of the RF waveform during a portion of the second time period.

[0007] Embodiments of this disclosure provide a waveform generator. The waveform generator typically includes a system controller coupled to it. The system controller typically includes a memory containing computer-executable instructions and one or more processors configured to execute the computer-executable instructions and to cause the waveform generator to transmit a radio frequency (RF) waveform at a frequency during a first time period using an RF generator, and subsequently to stop the transmission of the RF waveform during a second time period, and to transmit a pulsed voltage waveform at a first voltage during at least a portion of a third time period using a pulser, wherein the transmission of the pulsed voltage waveform overlaps with the transmission of the RF waveform during a portion of the second time period. Attached Figure Description

[0008] To gain a more detailed understanding of the features described above in the embodiments of this disclosure, a more specific description of the disclosure, which has been briefly summarized above, can be made with reference to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only typical embodiments of this disclosure and should therefore not be construed as limiting its scope, as other equivalent embodiments are permissible.

[0009] Figure 1 This is a schematic diagram of an exemplary processing system that can implement embodiments of the present disclosure.

[0010] Figure 2 The diagram illustrates two separate voltage waveforms generated on a substrate due to the voltage waveforms applied to the electrodes of the processing chamber, according to certain embodiments of this disclosure.

[0011] Figure 3 This is a flowchart of one or more waveform generation methods according to the embodiments described herein.

[0012] Figure 4 A diagram is shown illustrating, during a waveform generation method, exemplary RF generator power for generating radio frequency (RF) waveforms and exemplary pulser voltage for generating pulse voltage waveforms, according to one or more embodiments described herein.

[0013] Figure 5Another diagram illustrates one or more of the exemplary RF generator power for generating radio frequency (RF) waveforms and exemplary pulser voltages for generating pulse voltage waveforms, according to embodiments described herein.

[0014] Figure 6 Another diagram illustrates one or more of the exemplary RF generator power for generating radio frequency (RF) waveforms and exemplary pulser voltages for generating pulse voltage waveforms, according to embodiments described herein.

[0015] Figure 7 Another diagram illustrates one or more of the exemplary RF generator power for generating radio frequency (RF) waveforms and exemplary pulser voltages for generating pulse voltage waveforms, according to embodiments described herein.

[0016] Figure 8 Another diagram illustrates one or more of the exemplary RF generator power for generating radio frequency (RF) waveforms and exemplary pulser voltages for generating pulse voltage waveforms, according to embodiments described herein.

[0017] For ease of understanding, the same element symbols are used as much as possible to identify the same elements in the drawings. It is conceivable that elements disclosed in one embodiment may be advantageously used in other embodiments without specific description. Detailed Implementation

[0018] Embodiments of this disclosure generally relate to apparatus and methods for performing plasma-assisted processes. More specifically, the embodiments provided herein control the plasma during processing by controlling the propagation of pulsed radio frequency (RF) waveforms and pulsed voltage (PV) waveforms. In some embodiments, the process of controlling the plasma includes controlling the time overlap between pulses of the pulsed RF waveform and a series of pulses included within the PV waveform. It has been found that controlling the propagation and time overlap of pulses of the pulsed RF waveform and a series of voltage pulse trains within the PV waveform can be used to improve plasma processing results on a substrate during plasma processing. In one example, it has been found that by controlling the processing parameters of the PV waveform during one or more voltage pulse trains, plasma properties can be controlled to achieve improved processing results, such as improved narrow aspect ratio etching results and better contour control of the substrate during plasma processing. Generally, the voltage pulse train within the PV waveform will include a series of voltage pulses available to electrodes within the plasma processing chamber. Examples of processing parameters for the PV waveform may include PV on-time, PV pulse duty cycle, pulse frequency, PV pulse train length, and voltage setpoint of the PV waveform. Compared to conventional plasma-assisted processes that rely solely on the transmission of RF waveforms or pulsed RF waveforms to control the plasma during processing, these processing parameters can be manipulated as needed to provide enhanced control of the plasma-assisted process.

[0019] Processing System Instances

[0020] Figure 1 This is a schematic diagram of an exemplary processing system 10. The plasma processing system 10 is configured for plasma-assisted etching processes, such as reactive ion etching (RIE) plasma processing. The plasma processing system 10 can also be used for other plasma-assisted processes, such as plasma-enhanced deposition processes (e.g., plasma-enhanced chemical vapor deposition (PECVD), plasma-enhanced physical vapor deposition (PEPVD), plasma-enhanced atomic layer deposition (PEALD), plasma processing, plasma-based ion implantation, or plasma doping (PLAD)). In some embodiments, such as... Figure 1As shown, the plasma processing system 10 is configured to form capacitively-coupled plasma (CCP). In other embodiments, the plasma may alternatively be generated by an inductively coupled plasma (ICP) source disposed above the processing region of the plasma processing system 10.

[0021] The plasma processing system 10 includes a processing chamber 100, a substrate support assembly 136, a gas delivery system 182, a high-voltage direct current (DC) supply 173, an RF generator 171, and an RF matching unit 172 (e.g., an RF impedance matching network). The chamber cover 123 includes one or more sidewalls and a chamber base configured to withstand pressures and energy applied to these sidewalls and the chamber base during plasma 101 generation within the vacuum environment maintained in the processing volume 129 of the processing chamber 100 during processing.

[0022] A gas delivery system 182 coupled to a processing volume 129 of a processing chamber 100 is configured to deliver at least one processing gas from at least one gas processing source 119 to the processing volume 129 of the processing chamber 100. The gas delivery system 182 includes a processing gas source 119 and one or more gas inlets 128 positioned through a chamber cover 123. The gas inlets 128 are configured to deliver one or more processing gases to the processing volume 129 of the processing chamber 100.

[0023] The processing chamber 100 includes a chamber cover 123 and a substrate support assembly 136 positioned within a processing volume 129 of the processing chamber 100. In some embodiments, the chamber cover 123 is grounded and thus acts as an upper electrode during plasma processing. In some embodiments, an RF generator 171 is electrically coupled to a first lower electrode, such as an RF substrate 137. The RF generator 171 is configured to deliver an RF signal to ignite and sustain plasma 101 between the upper and lower electrodes. In one example, the RF generator 171 may deliver RF source power to the RF substrate 137 within the substrate support assembly 136 (e.g., a cathode assembly) for plasma generation. However, in some alternative configurations, the RF generator 171 may be electrically coupled to the upper electrode. The center frequency of the RF source power may range from 13.56 MHz to extremely high frequency bands, such as 40 MHz, 60 MHz, 120 MHz, or 162 MHz. The RF source power may operate in continuous or pulsed mode. The pulse frequency of the RF power can range from 100 to 10 kHz, and the duty cycle ranges from 5% to 95%. The RF generator 171 has frequency tuning capability and can adjust its RF power frequency within, for example, ±5% or ±10%. In some embodiments, the RF generator 171 switches the RF power frequency at a predefined speed (e.g., two nanoseconds, fifty nanoseconds, etc.).

[0024] A substrate support assembly 136 is coupled to an RF generator 171, which is configured to transmit RF signals to the processing volume 129 of the processing chamber 100. The RF generator 171 is electronically coupled to an RF matching device 172 disposed between the RF generator 171 and the processing volume 129 of the processing chamber 100. For example, the RF matching device 172 is circuitry used between the RF generator 171 and the plasma reactor (e.g., the processing volume 129 of the processing chamber 100) to optimize power transfer efficiency. One or more RF filters (e.g., within the RF matching device 172) are designed to allow power only within a selected frequency range and to isolate the RF power supplies from each other. In some cases, the bandwidth of the RF filters must be greater than the frequency tuning range of the RF generator 171.

[0025] During plasma processing, RF generator 171 transmits an RF signal to the RF substrate 137 of substrate support assembly 136 via RF matching device 172. For example, the RF signal is applied to a load (e.g., gas) in the processing volume 129 of processing chamber 100. If the impedance of the load is not properly matched to the impedance of the source (e.g., RF generator 171), a portion of the waveform will be reflected back in the opposite direction. Therefore, to prevent most of the waveform from being reflected back, it is necessary to find a matching impedance (e.g., a matching point) by adjusting one or more components of RF matching device 172 when the source impedance and load impedance change.

[0026] RF matcher 172 is electrically coupled to RF generator 171, substrate support assembly 136, and PV waveform generator 175. RF matcher 172 is configured to receive a synchronization signal from either or both of RF generator 171 and PV waveform generator 175.

[0027] A substrate support assembly 136 may be coupled to a high-voltage DC supply 173, which supplies a clamping voltage to the substrate support assembly. The high-voltage DC supply 173 may be coupled to a filter assembly 178, which is disposed between the high-voltage DC supply 173 and the substrate support assembly 136. The filter assembly 178 is configured to electronically isolate the high-voltage DC supply 173 during plasma processing. In one configuration, the quiescent DC voltage is between approximately -5000 V and approximately 5000 V and is transmitted using an electrical conductor (such as a coaxial power transfer line). The filter assembly 178 may include multiple filter elements or a single shared filter.

[0028] The substrate support assembly 136 is also coupled to a PV waveform generator 175, which is configured to supply PV to electrodes within the substrate support assembly 136 to bias a substrate disposed on the substrate support. The PV waveform generator 175 may be coupled to an RF substrate 137 or a second electrode, such as a clamping electrode 138, disposed within the substrate support assembly 136. The PV waveform generator 175 is coupled to a filter assembly 178, which is coupled to electrodes disposed within the substrate support assembly 136. The filter assembly 178 is disposed between the PV waveform generator 175 and the substrate support assembly 136. The filter assembly 178 is configured to electronically isolate the PV waveform generator 175 from at least the RF signal provided by the RF generator 171 during plasma processing.

[0029] RF generator 171 and PV waveform generator 175 are each directly coupled to system controller 126. System controller 126 synchronizes the RF signals and PV waveforms generated by each.

[0030] Voltage and current sensors can be placed at the inputs and / or outputs of the RF matching unit 172 to measure impedance and other parameters. These sensors can use external transistor-transistor logic (TTL) synchronization signals from an advanced waveform generator and / or RF generator, or use measured voltage and current data to determine internal timing for synchronization. For example, output sensor 117 is configured to measure the impedance of the plasma processing chamber 100, and other characteristics such as voltage, current, harmonics, phase, and / or similar parameters. Input sensor 116 is configured to measure the impedance of the RF generator 171, and other characteristics such as voltage, current, harmonics, phase, and / or similar parameters. Based on either the synchronization signal or the characteristics of the plasma processing chamber 100, the RF matching unit 172 can capture rapid impedance changes and optimize impedance matching.

[0031] A PV waveform generator 175 supplies a PV waveform and / or a custom voltage waveform, which is the sum of harmonic frequencies associated with the waveform. The PV waveform generator 175 can output a synchronous TTL signal to an RF matching unit 172. The voltage waveform is coupled to a bias electrode (e.g., bias electrode 104 shown in Figure 1B) via a filter assembly 178. During the process for thermal control, a high-voltage DC supply 173 is used to clamp the wafer. In some cases, a third electrode may be present at the edge of the cathode assembly for edge uniformity control.

[0032] Voltage waveform examples

[0033] Figure 2 Figure 200 illustrates two independent voltage waveforms generated at a substrate 103 disposed on a substrate receiving surface 105A of a substrate support assembly 136 in the processing chamber 100 due to the transmission of a PV waveform to a bias electrode 104 of the processing chamber 100. The first waveform (e.g., waveform 225) is an example of an uncompensated PV waveform generated at the substrate 103 during plasma processing. The second waveform (e.g., waveform 230) is an example of a compensated PV waveform generated at the substrate 103 by applying a negative slope waveform to the bias electrode 104 of the processing chamber 100 during the "ion current phase" portion of the PV waveform period using a current source 177. Alternatively, a compensated PV waveform can be generated by applying a negative voltage ramp during the ion current phase of the PV waveform generated by the PV waveform generator 175. The PV waveform periods of waveforms 225 and 230 each have a period T. p The period is typically between 2 microseconds (µs) and 10 µs, such as 2.5 µs. The ion current phase of the PV waveform period will typically occupy the period T. p Between approximately 50% and approximately 95%, such as in period T. p Approximately 80% to approximately 90%.

[0034] Waveforms 225 and 230 comprise two main phases: an ion current phase and a sheath collapse phase. During plasma processing, the two portions of waveforms 225 and 230 (e.g., the ion current phase and the sheath collapse phase) may be generated alternately and / or individually at substrate 103. At the beginning of the ion current phase, a voltage drop is generated at substrate 103 due to the transfer of the negative portion (e.g., the ion current portion) of the PV waveform supplied to the bias electrode 104 by the PV waveform generator 175, which creates a high-voltage sheath over substrate 103. The high-voltage sheath allows positive ions generated by the plasma to be accelerated toward the biased substrate 103 during the ion current phase, and therefore, for RIE processes, the high-voltage sheath controls the amount and characteristics of the etching process occurring on the surface of substrate 103 during plasma processing. Figure 2 As shown, the sheath collapse phase includes a positive voltage swing 240 (e.g., due to a positive wafer voltage), while the ion current phase includes a negative voltage swing (e.g., due to a positive wafer voltage). In some embodiments, it is desirable for the ion current phase to include a region of PV waveform in which a stable or minimally varying voltage is achieved at substrate 103 throughout the phase, such as Figure 2 Waveform 230 is shown in the diagram. It will be noted that the significant voltage variation generated at substrate 103 during the ion current phase, as shown by the positive slope in waveform 225, will undesirably lead to changes in the ion energy distribution (IED), and thus undesirable characteristics of the etched features formed in substrate 103 during the RIE process. The plasma sheath impedance varies with the supplied PV waveform voltage. RF matcher 172 can sample the impedance at different processing stages using either or both of the synchronization signals and / or its internal sensors. In one example, the synchronization signal or characteristic determined by input sensor 116 or output sensor 117 is used to trigger RF matcher 172 to determine at least two different impedances at different processing stages. Subsequently, RF matcher 172 updates its matching point based on the at least two different impedances.

[0035] Process monitoring and control examples

[0036] Figure 3 A flowchart of a waveform generation method 300 is shown, according to one or more embodiments described herein. Figure 4 FIG400 illustrates one or more of the exemplary RF generator power 410 for generating an RF waveform and the exemplary pulser voltage 420 for generating a PV waveform during waveform generation method 300, according to embodiments described herein. Therefore, for clarity, they are described together herein. Figure 3 and Figure 4In some embodiments, operating modes other than method 300 can be used to enable the transmission of PV waveforms after the transmission of RF waveforms has been stopped.

[0037] Method 300 includes, in activity 302, using an RF generator (e.g., RF generator 171) to transmit an RF waveform at a frequency during a first time period PT1, and subsequently stopping the transmission of the RF waveform during a second time period PT2. The RF waveform may include a series of RF pulses. In some embodiments, the first time period PT1 may include a first sub-time period P1 and a second sub-time period P2, while the second time period PT2 may include a third sub-time period P3 and a fourth sub-time period P4. The first time period PT1 and the second time period PT2 may be cyclically repeated to form a series of RF pulses, each pulse having a period (e.g., an RF pulse period) equal to the sum of the first time period PT1 and the second time period PT2, or in other words, equal to the sum of the first, second, third, and fourth sub-time periods. To transmit the RF waveform, the RF generator may provide RF generator power 410 to the upper electrode (e.g., chamber cover 123) and / or the lower electrode (e.g., RF substrate 137) of the processing chamber (e.g., processing chamber 100). In some cases, the RF generator power 410 can be provided with power W1 to generate an RF waveform, and the power W1 can be 300 watts (W). Power W1 can be between 50 W and 8000 W. The RF waveform can be a sinusoidal waveform, and the frequency at which the RF waveform is transmitted can be 13.56 MHz. In some embodiments, the second sub-time period P2 begins at the end of the first sub-time period P1 (e.g., at time T1), the third sub-time period P3 begins at the end of the second sub-time period P2 (e.g., at time T2), and the fourth sub-time period P4 begins at the end of the third sub-time period P3 (e.g., at time T3), as... Figure 4 As shown. In some cases, it is desirable to adjust one or more parameters of the RF waveform and / or PV waveform processing parameters during one or more cycles of the plasma processing cycle that performs multiple repetitive activities 302 and 304. In one example, it may be desirable to adjust at least one of the following during one or more cycles of the repetitive cycle: RF pulse period, RF pulse duty cycle, short pulse period T. BD Voltage pulse train operating cycle, ignition voltage (e.g., second voltage V1), first voltage V2, voltage pulse period T p RF power W1 and / or one or more of the sub-time periods. For example Figure 3 and Figure 4 As shown and discussed in method 300, the RF waveform provided by the RF generator can be asynchronously pulsed with the PV waveform to ignite and / or sustain the plasma within the processing area of ​​the plasma processing chamber.

[0038] It is generally accepted that after transmitting the RF waveform within the first time period PT1, which includes the first sub-time period P1 and the second sub-time period P2, the RF generator is turned off (e.g., the transmission of the RF waveform is stopped). The removal of RF power causes a sudden drop in electron temperature and electron density in the plasma, and the number of electrons in the plasma decays. It is generally accepted that during the early stages of the RF “off” period, a large percentage of fast electrons are lost due to the recombination or bombardment of the chamber walls, which subsequently leaves a high percentage of low-energy electrons in the plasma until the plasma extinguishes after a certain time period. In some embodiments, it is desirable to ensure that the second time period PT2 is short enough to prevent the plasma from extinguishing during one or more cycles in a repetitive cycle. The early stages of the RF “off” period of the RF pulse are often referred to as the afterglow period, which may include the near-afterglow period, during which ion-ion plasma and weak-energy electrons remain, and the plasma density decays slowly.

[0039] As described above, during the near-afterglow period, including the third sub-time period P3, a portion of the voltage pulse train of the PV waveform is provided by a pulser. Compared to the RF waveform provided to the plasma during the first time period PT1, this portion of the voltage pulse train causes plasma breakdown to occur at a lower rate during the near-afterglow period. Therefore, the PV waveform does not lead to any densification or generation of high-energy electrons in the plasma. Furthermore, during the third time period P3, fast ions in the plasma (e.g., plasma 101) (which, through the above-described...) Figure 2 Collisions may occur between the high-voltage sheath above the substrate 103 (which gains momentum) and slow-moving neutral particles, resulting in charge exchange between the ions and the neutral particles. Thus, the ions become slow ions, and the neutral particles become fast-moving neutral particles. It is also generally accepted that the process performed herein will affect the narrower ion angular distribution function (IADF) and the charge exchange collision process that produces oriented neutral particles. Furthermore, the PV waveform can be manipulated by changing the PV start-up time, duty cycle, voltage pulse frequency, and voltage setpoint by modifying the pulser voltage 420 during the third time period P3. It has been found that the technique discussed herein allows the PV waveform to be used as an orthogonal knob for controlling the bias of the plasma (e.g., plasma 101) during the third time period P3 (e.g., near the afterglow period). Therefore, and as described above, a narrower IEDF and enhanced contour control can be achieved during plasma-assisted etching processes (e.g., compared to plasma-assisted processes that use an RF generator to bias the plasma). The techniques discussed in this article may be particularly helpful during plasma-assisted cleaning processes with high aspect ratio features.

[0040] Figure 5 Figure 500 illustrates an exemplary RF generator power 510 for generating an RF waveform and an exemplary pulser voltage 520 for generating a PV waveform, according to one or more embodiments described herein. Figure 500 may be substantially similar to Figure 400, but may represent different pulse schemes. In the pulse scheme shown in Figure 500, the RF waveform is generated at power W1 in a first sub-time period P1, stops in the second sub-time period P2 and the third sub-time period P3 (e.g., the RF generator power 510 may be 0), is generated at power W2 in the fourth sub-time period P4, and stops in the fifth sub-time period P5 and the sixth sub-time period P6 (e.g., the RF generator power 510 may be 0). The PV waveform is transmitted at a first voltage V1 in the first sub-time period P1 and the second sub-time period P2, stops during the third sub-time period P3 (e.g., the voltage transmitted by the pulser may be 0), is transmitted at a second voltage V2 in the fourth sub-time period P4 and the fifth sub-time period P5, and stops during the sixth sub-time period P6 (e.g., the voltage transmitted by the pulser may be 0). In the pulse scheme shown in Figure 500, each of the second sub-time period P2 and the fifth sub-time period P5 can be included in the near-afterglow period, and thus the pulse scheme can achieve the above-mentioned benefits.

[0041] In the pulsed scheme shown in Figure 500, the power W1 can be higher than the power W2, and the first voltage V1 can be higher than the second voltage V2. Furthermore, the first sub-time period P1, the second sub-time period P2, and the third sub-time period P3 can be 50% of the plasma processing cycle of the RF waveform (e.g., the first time period PT1), and the fourth sub-time period P4, the fifth sub-time period P5, and the sixth sub-time period P6 can be 50% of the plasma processing cycle of the RF waveform (e.g., the second time period PT2).

[0042] Figure 6Figure 600 illustrates an exemplary RF generator power 610 for generating an RF waveform and an exemplary pulser voltage 620 for generating a PV waveform, one or more of the embodiments described herein. Figure 600 may be substantially similar to Figure 400, but may represent different pulse schemes. In the pulse scheme shown in Figure 600, the RF waveform is generated at power W1 in the first sub-time period P1 and the second sub-time period P2, at power W2 in the third sub-time period P3, and stops in the fourth sub-time period P4 and the fifth sub-time period P5 (e.g., the RF generator power 510 may be 0). The PV waveform is transmitted at a first voltage V1 in the first sub-time period P1, stops during the second sub-time period P2 (e.g., the voltage transmitted by the pulser may be 0), is transmitted at a second voltage V2 in the third sub-time period P3 and the fourth sub-time period P4, and stops during the fifth sub-time period P5 (e.g., the voltage transmitted by the pulser may be 0). In the pulse scheme shown in Figure 600, the fourth sub-time period P4 may be included in the near-afterglow period, and thus the pulse scheme can achieve the above-described benefits.

[0043] In the pulsed scheme shown in Figure 600, the power W1 can be higher than the power W2, and the first voltage V1 can be higher than the second voltage V2. Furthermore, the first sub-time period P1 and the second sub-time period P2 can be 20% of the plasma processing cycle of the RF waveform, the third sub-time period P3 can be 30% of the plasma processing cycle of the RF waveform, and the fourth sub-time period P4 and the fifth sub-time period P5 can be 50% of the plasma processing cycle of the RF waveform. The first sub-time period P1, the second sub-time period P2, and the third sub-time period P3 can form the first time period PT1, while the fourth sub-time period P4 and the fifth sub-time period P5 can form the second time period PT2.

[0044] Figure 7Figure 700 illustrates one or more of the exemplary RF generator power 710 for generating RF waveforms and the exemplary pulser voltage 720 for generating PV waveforms according to embodiments described herein. Figure 700 may be substantially similar to Figure 400, but may represent different pulse schemes. In the pulse scheme shown in Figure 700, the RF waveform is generated at power W1 in a first sub-time period P1, stops in the second sub-time period P2, the third sub-time period P3, and the fourth sub-time period P4 (e.g., the RF generator power 510 may be 0), is generated at power W2 in the fifth sub-time period P5, and stops in the sixth sub-time period P6, the seventh sub-time period P7, and the eighth sub-time period P8 (e.g., the RF generator power 510 may be 0). The PV waveform does not propagate during the first sub-time period P1 and the second sub-time period P2, propagates with a first voltage V1 during the third sub-time period P3, stops during the fourth sub-time period P4, the fifth sub-time period P5, and the sixth sub-time period P6 (e.g., the voltage propagated by the pulser may be 0), propagates with a second voltage V2 during the seventh sub-time period P7, and stops during the eighth sub-time period P8 (e.g., the voltage propagated by the pulser may be 0). In the pulse scheme shown in FIG700, each of the third sub-time period P3 and the seventh sub-time period P7 can be included in the near-afterglow period, which occurs after a delay (e.g., the second sub-time period P2 and the sixth sub-time period P6, respectively). In this way, the pulse scheme shown in FIG700 achieves the aforementioned benefits.

[0045] In the pulsed scheme shown in Figure 700, the power W1 can be higher than the power W2, and the first voltage V1 can be higher than the second voltage V2. Furthermore, the first sub-time period P1, the second sub-time period P2, the third sub-time period P3, and the fourth sub-time period P4 can each be 50% of the plasma processing cycle of the RF waveform (e.g., the first time period PT1), while the fifth sub-time period P5, the sixth sub-time period P6, the seventh sub-time period P7, and the eighth sub-time period P8 can each be 50% of the plasma processing cycle of the RF waveform (e.g., the second time period PT2).

[0046] Figure 8Figure 800 illustrates one or more of the exemplary RF generator power 810 for generating RF waveforms and the exemplary pulser voltage 820 for generating PV waveforms according to embodiments described herein. Figure 800 may be substantially similar to Figure 400, but may represent different pulse schemes. In the pulse scheme shown in Figure 800, the RF waveform is generated at power W1 in a first sub-time period P1, at power W2 in a second sub-time period P2, and stops during the third sub-time period P3, the fourth sub-time period P4, and the fifth sub-time period P5 (e.g., the RF generator power 810 may be 0). The PV waveform is transmitted at a first voltage V1 in the first sub-time period P1, stops during the second sub-time period P2 and the third sub-time period P3 (e.g., the voltage transmitted by the pulser may be 0), is transmitted at a second voltage V2 in the fourth sub-time period P4, and stops during the fifth sub-time period P5 (e.g., the voltage transmitted by the pulser may be 0). In the pulsed scheme shown in Figure 800, the fourth sub-time period P4 may be included in the near-afterglow period, which occurs after the delay (e.g., the third sub-time period P3). In this way, the pulsed scheme shown in Figure 800 achieves the aforementioned benefits.

[0047] In the pulsed scheme shown in Figure 800, the power W1 can be higher than the power W2, and the first voltage V1 can be higher than the second voltage V2. Furthermore, the first sub-time period P1 can be 20% of the plasma processing cycle of the RF waveform, the second sub-time period P2 can be 30% of the plasma processing cycle of the RF waveform, and the third sub-time period P3, the fourth sub-time period P4, and the fifth sub-time period P5 can be 50% of the plasma processing cycle of the RF waveform. The first sub-time period P1 and the second sub-time period P2 can form the first time period PT1, and the third sub-time period, the fourth sub-time period P4, and the fifth sub-time period P5 can form the second time period PT2.

[0048] In some embodiments, the method 300 and its operation described herein may be controlled by a system controller (e.g., Figure 1 The system controller 126 executes the commands. The system controller may include memory that includes computer-executable instructions and one or more processors configured to execute the computer-executable instructions and cause the waveform generator (e.g., a waveform generator including RF generator 171 and PV waveform generator 175) to perform method 300 and any other operations described herein.

[0049] Other precautions

[0050] In the foregoing description, details have been illustrated by way of examples to facilitate understanding of the disclosed content. However, it will be apparent to those skilled in the art that the disclosed embodiments are illustrative and do not exhaust all possible embodiments. Therefore, it should be understood that reference to the described examples is not intended to limit the scope of this disclosure. Those skilled in the art to which this disclosure pertains will readily conceive of any changes and further modifications to the described apparatus, instruments, and methods, and any further applications of the principles of this disclosure. Specifically, it is entirely conceivable that features, components, and / or steps described for one embodiment may be combined with features, components, and / or steps described for other embodiments of this disclosure. In this document, the term "about" may refer to a variation of + / - 10% relative to a nominal value. It should be understood that such variation may be included in any values ​​provided herein.

[0051] In this document, "a processor," "at least one processor," or "one or more processors" generally refers to a single processor configured to perform one or more operations, or multiple processors configured to jointly perform one or more operations. In the case of multiple processors, the execution of one or more operations may be divided among different processors, although one processor may perform multiple operations, and multiple processors may jointly perform a single operation. Similarly, "a memory," "at least one memory," or "one or more memories" generally refers to a single memory configured to store data and / or instructions, or multiple memories configured to jointly store data and / or instructions.

[0052] In this article, the phrase “at least one” in the list of items refers to any combination of these items, including a single member. For example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, and any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c).

[0053] The methods disclosed herein include one or more steps or actions to implement the methods. These method steps and / or actions may be interchanged without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of a particular step and / or action may be modified without departing from the scope of the claims.

[0054] Although the foregoing describes embodiments of this disclosure, other and further embodiments of this disclosure may be designed without departing from the basic scope of this disclosure, the scope of which is defined by the appended claims.

Claims

1. A method for waveform generation, comprising the following steps: A radio frequency (RF) generator is used to transmit an RF waveform at a frequency during a first time period, and then the transmission of the RF waveform is stopped during a second time period. and A pulse voltage waveform is transmitted at a first voltage using a pulser for at least a portion of a third time period, wherein during a portion of the second time period, the transmission of the pulse voltage waveform overlaps with the cessation of the transmission of the RF waveform.

2. The method of claim 1, wherein the step of transmitting the pulse voltage waveform with the first voltage comprises the following steps: The pulse voltage waveform is transmitted with the first voltage during the third time period.

3. The method according to claim 1, further comprising the following steps: The pulse voltage waveform is transmitted with a second voltage during a first portion of the first time period, and the transmission of the pulse voltage waveform is then stopped during a second portion of the first time period, wherein the transmission of the RF waveform overlaps with the transmission of the pulse voltage waveform during the first portion of the first time period.

4. The method according to claim 1, wherein the pulse voltage waveform includes pulses having positive voltage oscillations and negative voltage oscillations.

5. The method according to claim 1, wherein the first time period includes a first sub-time period and a second sub-time period, wherein the second time period includes a third sub-time period and a fourth sub-time period, wherein the portion of the second time period includes the third sub-time period, and wherein the second sub-time period begins at the end of the first sub-time period, the third sub-time period begins at the end of the second sub-time period, and the fourth sub-time period begins at the end of the third sub-time period.

6. The method of claim 5, wherein the first sub-time period is 20% of the cycle of the RF waveform and the pulse voltage waveform.

7. The method of claim 5, wherein the second sub-time period is 40% of the cycle of the RF waveform and the pulse voltage waveform, the third sub-time period is 20% of the cycle of the RF waveform and the pulse voltage waveform, and wherein the fourth sub-time period is 20% of the cycle of the RF waveform and the pulse voltage waveform.

8. The method of claim 1, wherein during a portion of the second time period, the pulse voltage waveform does not overlap with the RF waveform.

9. The method of claim 1, wherein during a portion of the second time period, the pulse voltage waveform overlaps with the RF waveform.

10. The method of claim 1, further comprising the following steps: The RF waveform is transmitted at the first frequency during a fourth time period using the RF generator, and then the transmission of the RF waveform is stopped during a fifth time period. and The pulser is used to transmit the pulse voltage waveform at the first voltage for at least a portion of the sixth time period, wherein during a portion of the fifth time period, the transmission of the pulse voltage waveform overlaps with the cessation of the transmission of the RF waveform.

11. A waveform generator, comprising: A system controller, coupled to the waveform generator, includes a memory containing computer-executable instructions and one or more processors configured to execute the computer-executable instructions and cause the waveform generator to: An RF generator is used to transmit a radio frequency (RF) waveform at a frequency during a first time period, and then the transmission of the RF waveform is stopped during a second time period. and A pulse voltage waveform is transmitted at a first voltage using a pulser for at least a portion of a third time period, wherein during a portion of the second time period, the transmission of the pulse voltage waveform overlaps with the cessation of the transmission of the RF waveform.

12. The waveform generator of claim 11, wherein the memory includes further computer-executable instructions that, when executed by the one or more processors, cause the waveform generator to transmit the pulse voltage waveform at the first voltage during the third time period.

13. The waveform generator of claim 11, wherein the memory includes further computer-executable instructions that, when executed by the one or more processors, cause the waveform generator to: The pulse voltage waveform is transmitted with a second voltage during a first portion of the first time period, and the transmission of the pulse voltage waveform is then stopped during a second portion of the first time period, wherein the transmission of the RF waveform overlaps with the transmission of the pulse voltage waveform during the first portion of the first time period.

14. The waveform generator of claim 11, wherein the pulse voltage waveform comprises a pulse having positive voltage oscillations and negative voltage oscillations.

15. The waveform generator of claim 11, wherein the first time period includes a first sub-time period and a second sub-time period, wherein the second time period includes a third sub-time period and a fourth sub-time period, wherein the portion of the second time period includes the third sub-time period, and wherein the second sub-time period begins at the end of the first sub-time period, the third sub-time period begins at the end of the second sub-time period, and the fourth sub-time period begins at the end of the third sub-time period.

16. The waveform generator of claim 15, wherein the first sub-time period is 20% of the cycle of the RF waveform and the pulse voltage waveform, and wherein the second sub-time period is 40% of the cycle of the RF waveform and the pulse voltage waveform.

17. The waveform generator of claim 15, wherein the third sub-time period is 20% of the cycle of the RF waveform and the pulse voltage waveform, and wherein the fourth sub-time period is 20% of the cycle of the RF waveform and the pulse voltage waveform.

18. The waveform generator of claim 11, wherein the one or more processors are configured to execute the computer-executable instructions and cause the waveform generator to deliver the pulse voltage waveform at the first voltage during at least a portion of the third time period, such that the pulse voltage waveform does not overlap with the RF waveform during the portion of the second time period.

19. The waveform generator of claim 11, wherein the one or more processors are configured to execute the computer-executable instructions and cause the waveform generator to deliver the pulse voltage waveform at the first voltage during at least a portion of the third time period, such that the pulse voltage waveform overlaps with the RF waveform during the portion of the second time period.

20. The waveform generator of claim 11, wherein the memory includes further computer-executable instructions that, when executed by the one or more processors, cause the waveform generator to: The RF waveform is transmitted at the first frequency during a fourth time period using the RF generator, and then the transmission of the RF waveform is stopped during a fifth time period; and The pulser is used to transmit the pulse voltage waveform at the first voltage for at least a portion of the sixth time period, wherein during a portion of the fifth time period, the transmission of the pulse voltage waveform overlaps with the cessation of the transmission of the RF waveform.

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