High-voltage plasma control

Abstract

A high-voltage pulsing power supply system is disclosed that includes a DC power source, a switch circuit electrically coupled to the DC power source, a droop control circuit coupled to the switch circuit, and / or an output. The switch circuit includes a plurality of switch modules and generates a plurality of pulses. The droop control circuit includes a droop diode, a droop inductor, and a droop element. The droop diode may be electrically coupled in series between the switch circuit and a primary winding of a transformer and allows negative pulse portions of the plurality of pulses to pass from the switch circuit to the primary winding of the transformer. The droop inductor and droop element are disposed in series across the droop diode to allow negative pulse portions of the plurality of pulses to pass from the switch circuit to the primary winding of the transformer and / or store energy from the negative pulse portions of the plurality of pulses.

Description

[Technical Field]

[0001] This invention relates to high-voltage plasma control. [Background technology]

[0002] In thin-film and semiconductor manufacturing technologies, the application of RF-excited gas discharge is standard practice. Positive ions generated within the plasma volume are accelerated between plasma sheaths to the electrodes by an ion energy distribution function, which is determined by the magnitude and waveform of the time-dependent potential difference between the sheaths, gas pressure, the physical shape of the reactor, and / or other factors. This ion impact energy distribution can determine the degree of anisotropy in thin-film etching, the magnitude of surface damage caused by ion collisions, the aspect ratio and / or diameter and / or depth of holes and other etched features, the etching rate of features, and other factors. Controlling the ion energy distribution function is crucial for processes involving plasma etching.

[0003] A high-voltage power supply system is required to generate the potential necessary to accelerate ions in the plasma. This high-voltage power supply system can provide a well-shaped (e.g., nearly flat between pulses) power waveform to generate various desired ion energy distribution functions. A different waveform may be used for each pulse, each potentially generating a different ion energy distribution function, thereby generating completely separate and collectively effective ion energy distribution functions over time. By controlling the ion energy distribution function, individual features of the etching process can be controlled.

[0004] In some applications, the portion of the waveform that generates the ion energy distribution function can be altered by the plasma chamber. For example, in semiconductor processing systems, the ion current in the plasma can cause droop between consecutive pulses in the waveform on a wafer. Such waveform changes can directly affect and / or alter the desired ion energy distribution function, thereby reducing the effectiveness of any process within the chamber. For instance, inter-pulse droop tends to broaden the ion energy distribution function, resulting in more low-energy ions. [Overview of the project] [Means for solving the problem]

[0005] A high-voltage pulsing power supply system is disclosed. The high-voltage pulsing power supply system includes a DC power supply, a switch circuit electrically coupled to the DC power supply, a droop control circuit coupled to the switch circuit, and / or an output. The output may be coupled to, for example, a plasma chamber. The high-voltage pulsing power supply system may also include an energy recovery circuit. The switch circuit may include a plurality of switch modules arranged in a full-bridge configuration, a half-bridge configuration, or other bridge configuration, and may generate a plurality of pulses having positive pulse portions and negative pulse portions. The transformer may include a transformer core, a primary winding, and a secondary winding. The droop control circuit may include a droop diode, a droop inductor, and / or a droop element, the droop element may be a resistive element or an energy recovery circuit. The energy recovery circuit may be any set of electrical components typically found in a DC-DC converter that transitions energy from one potential to another.

[0006] A droop element may be any component or combination of components used to adjust, for example, how much current flows through a droop inductor. A droop element can operate by limiting the energy injected into the droop inductor so that a balanced current can be maintained, or so that a specified current can be maintained. Passive droop elements, such as fixed resistors, allow a steady balanced current to be maintained, while active droop elements allow the current flowing through the droop inductor to change over time. A droop diode may be electrically coupled in series between a switch circuit and the primary winding of a transformer, and / or may allow positive pulse portions of multiple pulses to pass from the switch circuit to the primary winding of the transformer. The inductance in series with the droop diode may be individually selected to realize a positive pulse with a specific shape. This inductance in series with the droop diode may be set so that the rising pulse has a clean, rounded sinusoidal shape without cuts, dips, or multiple peaks / ringing. Droop inductors and droop elements may be placed in series across a droop diode to allow the negative pulse portions of multiple pulses to pass from the switch circuit to the primary winding of a transformer. The combination of droop inductors and droop elements makes it possible to control how much energy is stored in the droop inductor and / or how much current flows through it. The current flowing through the droop inductor may be closely related to the voltage applied across the plasma and / or the generated ion energy distribution function. The disclosed high-voltage pulsing power supply system can generate multiple different, time-varying composite ion energy distribution functions, for example, by varying its output over time, pulse by pulse and / or burst by burst and / or train by train.

[0007] The various embodiments described in this summary and document do not limit or define the scope of this disclosure or the claims. [Brief explanation of the drawing]

[0008] [Figure 1] This is a circuit diagram of a high-voltage pulsing power supply and plasma system. [Figure 2A] ~ [Figure 2B] Figure 1 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 3A] ~ [Figure 3B] Figure 1 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 4] This is a circuit diagram of a high-voltage pulsing power supply and plasma system. [Figure 5A] ~ [Figure 5B] Figure 4 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 6A] ~ [Figure 6B] Figure 4 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 7] This is a circuit diagram of a high-voltage pulsing power supply and plasma system with an energy recovery circuit. [Figure 8A] ~ [Figure 8B] Figure 7 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 9] Figure 7 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 10A] ~ [Figure 10B] Figure 7 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 11] Figure 7 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 12] This is a circuit diagram of a high-voltage pulsing power supply and plasma system with an active droop control circuit. [Figure 13] Figure 12 shows the output waveforms from the high-voltage pulsing power supply and plasma system. [Figure 14A] Shows the output waveforms from the high-voltage pulsing power supply and the plasma system shown in FIG. 12. [Figure 14B] Shows the switching logic used to generate the waveform shown in FIG. 14A. [Figure 15A] Shows the output waveforms from the high-voltage pulsing power supply and the plasma system shown in FIG. 12. [Figure 15B] Shows the output waveforms from the high-voltage pulsing power supply and the plasma system shown in FIG. 12. [Figure 16A] Shows the output waveforms from the high-voltage pulsing power supply and the plasma system shown in FIG. 12. [Figure 16B] Shows the switching logic used to generate the waveform shown in FIG. 16A. [Figure 17A] Shows an enlarged view of the waveform shown in FIG. 16A. [Figure 17B] Shows an enlarged view of the waveform shown in FIG. 16A. [Figure 17C] Shows an enlarged view of the waveform shown in FIG. 16A. [Figure 17D] Shows an enlarged view of the waveform shown in FIG. 16A. [Figure 18] Shows the ion energy distribution of ions in an exemplary chamber of the high-voltage pulsing power supply and the plasma system shown in FIG. 12. [Figure 19] Shows the ion energy distribution of ions in an exemplary chamber of the high-voltage pulsing power supply and the plasma system shown in FIG. 12. [Figure 20A] Shows the lower limit of the energy distribution function. [Figure 20B] Shows the upper limit of the energy distribution function. [Figure 21] Is a circuit diagram of a high-voltage pulsing power supply and a plasma system having a droop control circuit and an energy control circuit. [Figure 22] Shows the ion energy distribution of ions in the high-voltage pulsing power supply and the plasma system shown in FIG. 21. [Figure 23A] Shows the lower limit of the ion energy distribution. [Figure 23B] This indicates the upper limit of the ion energy distribution. [Figure 24] The circuit diagram for a high-voltage pulsing power supply and plasma system with an active droop control circuit is shown. [Figure 25] This is a flowchart illustrating an exemplary process for controlling the voltage droop on the wafer between pulses. [Figure 25] This is a flowchart illustrating an exemplary process for controlling the ion energy distribution on a wafer. [Figure 26] An example waveform showing two pulse bursts is shown. [Figure 27] This document contains some of the embodiments described herein, along with a block diagram of a computer system that can be used to implement those embodiments. [Modes for carrying out the invention]

[0009] Disclosed is a high-voltage pulsing power supply that generates high-voltage pulses. The high-voltage pulsing power supply may be coupled, for example, to one or more plasma chambers. The high-voltage pulsing power supply can, for example, compensate for voltage droop on the wafer in the plasma processing chamber. The high-voltage pulsing power supply can, for example, perform energy recovery in the pulsing circuit. The high-voltage pulsing power supply can, for example, enable the generation of a narrow or specific ion energy distribution ("ion energy distribution function") in the plasma. The high-voltage pulsing power supply can, for example, enable the generation of a wide range of ion energy distribution functions in the plasma. The high-voltage pulsing power supply can, for example, enable the generation of a time-varying ion energy distribution function in the plasma. The high-voltage pulsing power supply can, for example, enable operation at a variety of wafer voltage levels that may vary over time ("multilevel control") and / or, in particular, enable the duration of either or both of the positive and negative portions of the pulse to vary over time.

[0010] A pulse is a high-voltage waveform in which a voltage that was initially a first voltage rapidly reaches a peak and briefly becomes a second voltage, and then returns to approximately the first voltage. A pulse may be positive, negative, or bipolar (both positive and negative). A pulse may have pulse width (e.g., full width, half-width), amplitude (e.g., the second voltage), rise time (e.g., the time it takes for the waveform to change from the first voltage to the second voltage), and / or fall time (e.g., the time it takes for the waveform to return from the second voltage to the first voltage).

[0011] A burst (or pulse burst) is a sequence of pulses. A train (or pulse train) is a series of bursts. Figure 26 shows an example of a pulse train with two bursts. Each burst has at least a pulse repetition frequency, a burst duration, and / or a burst period.

[0012] High-voltage pulsing power supplies can compensate for voltage droop (e.g., voltage gradient between pulses) on the wafer in the plasma processing chamber. Voltage droop may be partially removed, completely removed, partially inverted, and / or completely inverted. For example, a wafer with a negative peak voltage of -6kV may have a voltage droop of -2kV by the end of the negative portion of the pulse. A high-voltage pulsing power supply may, for example, maintain the wafer voltage constant around -6kV for the entire negative pulse, most of the negative pulse, or a portion of the negative pulse until the wafer voltage droops. A high-voltage pulsing power supply may also allow the wafer voltage to slope more negatively over time, for example, so that the wafer voltage changes from -6kV to -10kV during the negative portion of the pulse. A high-voltage pulsing power supply may operate in the range of, for example, ±100V to ±100kV. This voltage range may encompass both the absolute voltage range applied to the wafer and the range in which the power supply can change the voltage from a voltage that would result from wafer droop. A high-voltage pulsing power supply may control a negative wafer voltage, for example, when the voltage exceeds 100V.

[0013] The average power delivered by a high-voltage pulsing power supply (e.g., averaged over multiple bursts and / or trains) may be greater than 10W, 100W, 1000W, or 100kW. A typical average power delivered by a high-voltage pulsing power supply may be greater than, for example, 1kW. The power delivered by a high-voltage pulsing power supply (e.g., averaged over a single burst) may be, for example, 1, 5, or 30 times the average power delivered.

[0014] Droop control of the negative portion of the pulse (e.g., wafer waveform control) can operate over durations of, for example, 100 ns, 1 μs, 10 μs, 100 μs, and / or 1 ms.

[0015] The positive portion of the pulse may be used, for example, to break down the sheath / electron potential and push electrons onto the wafer in the plasma processing chamber, neutralizing the charge accumulated as the ionic current flows through the wafer during the negative portion of the pulse. The positive portion of the pulse may operate for durations of, for example, about 100 ns, 1 μs, 10 μs, 100 μs, and / or 1 ms. The width and / or rise time of the positive portion of the pulse may be used, for example, to control plasma properties, particularly the plasma potential relaxation time and degree of ionization.

[0016] High-voltage pulsing power supplies can control the ratio of the positive portion of a pulse to the negative portion of a pulse. This ratio may be in the range of, for example, 1% to 100%. This ratio may be set, for example, to control the magnetic flux in the transformer core and to control various plasma characteristics, such as how positive and negative plasma sheaths are formed and collapse, how much negative charge is transferred to the wafer during the positive portion of the pulse, and / or how much etching of the chamber wall occurs during the positive portion of the pulse. This ratio may be set to optimize the etching process and individual or multiple aspects of a feature. For example, if the feature size is small and a high aspect ratio is desired, this ratio may be set to the lower end of that range, in which case the positive portion of the pulse will be significantly shorter than the negative portion of the pulse. This ratio may be adjusted so that the magnetic flux in the transformer core is kept below 1T.

[0017] The high-voltage pulsing power supply can generate high-voltage pulses when the plasma ion current is approximately 10 mA to approximately 300 A. The high-voltage pulsing power supply can generate high-voltage pulses when the chuck capacitance (represented, for example, by capacitor 12) is approximately 0.3 nF to approximately 1000 nF. The high-voltage pulsing power supply can generate high-voltage pulses in a plasma with a neutral density of approximately 0.1 mT to approximately 1000 mT and / or consisting of a single gas species or various gas species. The high-voltage pulsing power supply has a capacity of 10 per cubic meter 15 ~10 19 It is possible to generate high-voltage pulses in a plasma where individual particles are ionized. High-voltage pulsing power supplies can generate high-voltage pulses over a wide range of plasma conditions and / or chamber types.

[0018] For example, an inductor 184 in series with a droop diode 183 may be useful for generating a positive pulse of a specific shape. The inductor 184 in series with the droop diode 183 may be configured such that the shape of the rising pulse is a clean, rounded sinusoid (for example, a sinusoid without cuts, dips, or multiple peaks / ringing, as shown in the pulse of waveform 210 in Figure 2). The inductor 184 may have an inductance in the range of approximately 0.1 nH to approximately 10 μH, for example, measured on the primary side of the transformer. The inductor 184 may consist only of parasitic stray inductance (and not include any physical components). The inductor 184 may have an inductance less than approximately 100 nH, for example.

[0019] The high-voltage pulsing power supply may include an energy recovery circuit (for example, as shown in Figures 7 and 12). The energy recovery circuit may include, for example, a DC-DC converter (e.g., a rectifier bridge 730) that transitions energy from one voltage level to another. The energy recovery circuit may operate at voltages from, for example, about 1V to about 5000V. The energy recovery circuit may operate at power levels from, for example, about 10W to about 100kW. The energy recovery circuit may operate as a simple DC-DC converter that operates between two fixed voltages that remain constant over time or change over time. The time required for the DC-DC converter to adjust the voltage range in which it operates is in the range of about 1μs to about 1ms. The DC-DC converter may be based on various bridge topologies (e.g., half-bridge or full-bridge), among many other possible topologies. The energy recovery circuit can recover energy from a circuit (e.g., a droop inductor) that would otherwise be lost. While this energy is being recovered, the energy recovery circuit can, for example, adjust the current flowing through the droop inductor and / or adjust the voltage waveform and / or amplitude applied to the wafer and / or plasma.

[0020] High-voltage pulsing power supplies can generate a narrow ion energy distribution function within the plasma, for example, by reducing and / or eliminating wafer voltage droop. For example, a uniform voltage maintained across both ends of the plasma can generate a narrow ion energy distribution function. By changing the voltage waveform applied to the plasma with a high-voltage pulsing power supply, a wide range of ion energy distribution functions can be generated within the plasma. For example, the ion energy distribution function may range from a very sharp ion energy distribution function (see, e.g., Figure 22) to a flat ion energy distribution function, and may also range to an ion energy distribution function very similar to that generated by a standard sinusoidal power supply used for plasma etching.

[0021] As another example, a high-voltage pulsing power supply can generate a time-varying ion energy distribution function. For example, a high-voltage pulsing power supply can adjust the wafer voltage and / or wafer waveform (e.g., pulse width, pulse repetition frequency, pulse period, etc.) pulse by pulse, and / or burst by burst, and / or pulse train by pulse. For example, it is possible to combine a series of pulses, each having a peak in the ion energy distribution function at a different location, to generate a nearly flat composite ion energy distribution function. Such a composite ion energy distribution function can be generated from any number of pulses, for example, containing any arbitrary distribution of waveform, voltage, and / or ion energy distribution function.

[0022] A high-voltage pulsing power supply can generate any composite ion energy distribution function. The ion energy distribution function may be programmed and / or adjusted in real time to optimize various wafer etching parameters or ion energy distribution function parameters (e.g., etching rate, mask erosion rate, feature aspect ratio, feature bow growth rate, feature profile, feature size, bottom hole diameter, etc.). The generation of the ion energy distribution function may be performed, for example, when (e.g.) 90% of the ions fall within a band representing 10% of the total width of the energy distribution, and / or when the distribution is approximately flat over its entire range. The ion energy distribution function may change, for example, on a timescale up to 100 ns, or on a timescale of approximately 10 μs to approximately 100 μs. The possible rate of change of the ion energy distribution function may be set, for example, by the rate at which the energy recovery circuit can adjust the DC voltage level when the high-voltage pulsing power supply is operating.

[0023] High-voltage pulsing power supplies can enable operation at a variety of wafer voltage levels (or voltage states) that vary over time in discrete bursts or trains, as shown in Figure 16A. Such operation is sometimes referred to as multilevel control or bilevel control.

[0024] Droop in a plasma chamber can occur, for example, when current flows between the negative portions of an applied waveform (e.g., droop 221 shown in Figure 2B). This droop can, for example, charge the plasma contact surface and / or discharge a series capacitance, thereby generating a voltage that can be seen over time due to plasma drop. Often, this occurs, for example, during semiconductor plasma etching processes, where etching current flows across the wafer surface, lowering the voltage across the chuck capacitance. As the voltage across the chuck capacitance decreases, the etching voltage (i.e., the voltage applied across the plasma) also decreases.

[0025] Voltage droop can be determined by the equation I = C·dV / dt, where I is the plasma current flowing into the plasma and C is the series capacitance (e.g., wafer chuck capacitance (e.g., capacitor 12)). dV / dt is the rate at which the voltage across the series capacitance changes due to the flow of plasma current during the etching process. As plasma current flows into the series capacitance, the series capacitance discharges the voltage established at the start of the pulse, which was the voltage the series capacitance was charged with, according to the equation I = C·dV / dt. A high-voltage pulsing power supply can be operated to cancel the voltage droop observed across the series capacitance and plasma, which is done, for example, by preventing the discharge of the series capacitance. To do this, the high-voltage pulsing power supply may apply a gradient voltage to the opposite side of the series capacitance, which keeps the voltage across both the series capacitance and the plasma constant by effectively canceling the dV / dt voltage droop caused by the flow of ion current.

[0026] To cancel current droop caused by ion current and / or etching current, a high-voltage pulsing power supply can cancel the voltage droop that would otherwise occur by generating another voltage droop and / or voltage change on the opposite side of the series capacitance. A droop inductor (e.g., droop inductor 187) can establish the gradient voltage necessary to keep the plasma voltage constant between pulses, for example.

[0027] If the droop inductor is sized to keep the current relatively constant during a pulse (for example, if the current balances the plasma ion current and / or etching current), then the natural operation of the droop inductor directly applies the dV / dt required to keep the voltages across both the plasma and the series capacitance constant to the other side of the capacitance. Because the current flowing through the droop inductor deviates from the ion current flowing in the plasma during the negative portion of the pulse, the corresponding voltage drop across the plasma and the ion energy distribution function change as a result. The current flowing through the droop inductor can determine both the voltage and / or voltage waveform observed across the plasma.

[0028] A high-voltage pulsing power supply can control the current flowing through a droop inductor. The droop inductor may include, for example, a physical element such as an inductor and / or stray inductance in other circuit elements. The droop inductor and / or energy recovery circuit can control the current flowing through the droop inductor.

[0029] The size of the droop inductor may be set to any size in the range of approximately 1 μH to approximately 10 mH. The size of the droop inductor may be used in particular to define specific features of the desired waveform, and the speed at which the waveform is applied to the plasma is adjustable.

[0030] Ion energy distribution can be a crucial factor in semiconductor plasma processing. For example, a relatively flat and low ion energy distribution with spikes at specific energy levels can improve etching processes or other processes. This can, for instance, allow most of the energy from the power supply to be concentrated in the plasma at a specific energy level. The high-voltage pulsing power supply disclosed herein may be capable of controlling the ion energy distribution within the plasma.

[0031] Real-time feedback and control may be used to control the voltage waveform applied to the wafer. The voltage waveform may be measured directly in or near the chamber or wafer (e.g., at points 134 and / or 135) and / or calculated based on current and voltage measurements from other circuit elements. The amount of energy recovered and / or dissipated by the energy recovery circuit may be adjusted, for example, to generate a specific wafer voltage waveform. The magnitude of the current flowing through the droop inductor (e.g., droop inductor 187) may be adjusted, for example, by real-time feedback, which may be done to optimize, for example, the etching parameters of the plasma and wafer (e.g., ion energy distribution function). The time scale of the real-time feedback and control may be faster than 1 Hz, 1 kHz, or 100 kHz. This real-time feedback and control may be possible with an active energy recovery circuit. Even with a passive energy recovery circuit, real-time feedback and control may be possible by using a variable passive element such as a time-variable resistor. Possible real-time feedback and control parameters include, for example, the width of the positive portion of the pulse (e.g., rise time), the width of the negative portion of the pulse (e.g., fall time), the time between the positive and negative portions of the pulse, the pulse repetition frequency, and the switch timing signal. Numerous timing elements may be used to achieve real-time feedback and control. Real-time feedback and control can be achieved by changing the voltage applied to the pulsing power supply.

[0032] Figure 1 is a circuit diagram of a high-voltage pulsing power supply and plasma system 100. The high-voltage pulsing power supply and plasma system 100 may include, for example, a high-voltage pulsing power supply 105 and a plasma chamber 106. The plasma chamber 106 represents the effective circuit of the plasma within the plasma chamber.

[0033] The high-voltage pulsing power supply 105 is illustrated as a full-bridge configuration, but it can also operate in a half-bridge configuration or any other arbitrary bridge configuration. The high-voltage pulsing power supply 105 may include multiple switch modules in a full-bridge configuration, which are coupled to a DC power supply 150 and energy storage capacitor 155, and a DC power supply 151 and energy storage capacitor 156. Energy storage capacitor 156 and DC power supply 151 are switched by switch modules 162 and 164 to generate positive pulses. Energy storage capacitor 155 and DC power supply 150 are switched by switch modules 161 and 163 to generate the negative portion of each pulse. DC power supplies 150 and 151 may be the same power supply, and energy storage capacitors 155 and 156 may be the same capacitor charged to the same voltage. The charging voltage range of DC power supplies 150 and 151 may be, for example, about 0 to about 1000V, or about 0 to about 3000V.

[0034] The high-voltage pulsing power supply 105 may be coupled to a droop control circuit 110. The droop control circuit 110 may be coupled to, for example, a transformer 145. The droop control circuit 110 can, for example, reduce or decrease voltage droop in the plasma chamber (for example, on the wafer in the plasma chamber).

[0035] The high-voltage pulsing power supply and plasma system 100 may, for example, generate bipolar pulses. The bipolar pulse may be waveformd to include, for example, a positive pulse followed by a negative pulse. The bipolar pulse may be represented as a single pulse having both a positive pulse portion and a negative pulse portion, as shown in the output waveform 205 and wafer waveform 210 in Figures 2A and 2B. The peak-to-peak voltage between the positive and negative pulses may be greater than approximately 500V, 1kV, 2kV, 5kV, 10kV, 15kV, 20kV, 100kV, etc.

[0036] The high-voltage pulsing power supply and plasma system 100 may generate pulses including positive pulses with peak voltages higher than, for example, approximately 250V, 500V, 1kV, 2kV, 5kV, 10kV, 15kV, 100kV, etc. The high-voltage pulsing power supply 105 may generate pulses including negative pulses with negative peak voltages lower than, for example, approximately -250V, -500V, -1kV, -2kV, -5kV, -10kV, -15kV, -100kV, etc.

[0037] The high-voltage pulsing power supply and plasma system 100 can generate pulses with, for example, a high pulse repetition frequency (e.g., higher than 1kHz, 10kHz, 100kHz, 200kHz, 500kHz, 1MHz, etc.), a fast rise time (e.g., a rise time shorter than approximately 1ns, 10ns, 50ns, 100ns, 250ns, 500ns, 1000ns, 10μs, etc.), a fast fall time (e.g., a fall time shorter than approximately 1ns, 10ns, 50ns, 100ns, 250ns, 500ns, 1000ns, 10μs, etc.), and / or a short pulse width (e.g., a pulse width shorter than approximately 10μs, 1000ns, 500ns, 250ns, 100ns, 20ns, etc.).

[0038] The high-voltage pulsing power supply and plasma system 100 may generate pulses including, for example, combinations of pulses that may include any combination of positive pulses, negative pulses, and / or bipolar pulses.

[0039] The high-voltage pulsing power supply and plasma system 100 may include, for example, a high-voltage pulsing power supply 105. The high-voltage pulsing power supply 105 may be, for example, a half-bridge circuit or a full-bridge circuit. The high-voltage pulsing power supply 105 may include a DC power supply 150 together with an energy storage capacitor 155.

[0040] The high-voltage pulsing power supply 105 may include, for example, four switch modules 161, 162, 163, and 164. Each of the switch modules 161, 162, 163, and 164 may include, for example, any number of solid-state switches arranged in series or parallel. The switch modules 161, 162, 163, and 164 may include, for example, any type of solid-state switch, such as IGBTs, MOSFETs, SiC MOSFETs, SiC junction transistors, FETs, SiC switches, GaN switches, photoconductive switches, etc. The switch modules 161, 162, 163, and 164 may be switched at high frequencies and / or generate high-voltage pulses. These frequencies may include, for example, frequencies of about 10 kHz, 400 kHz, 0.5 MHz, 2.0 MHz, 4.0 MHz, 13.56 MHz, 27.12 MHz, 40.68 MHz, 50 MHz, etc. These frequencies may be greater than, for example, 10 kHz. Each switch module 161, 162, 163, and 164 may or may not contain the same number or type of solid-state switches as the other switch modules.

[0041] Each switch module 161, 162, 163, and 164 may include one or more solid-state switches S1 (e.g., solid-state switches such as IGBTs, MOSFETs, SiC MOSFETs, SiC junction transistors, FETs, SiC switches, GaN switches, photoconductive switches, etc.)).

[0042] Each switch module 161, 162, 163, and 164 may be coupled in parallel with its respective bridge diode 171, 172, 173, and 174, and may include stray inductance and / or stray resistance. Multiple diodes may be used for each switch, on the other hand, some switches may have no associated diodes, and some switches may share one or more common diodes. The stray inductance of each switch module may be, for example, equivalent. The stray inductance of a switch module may be less than, for example, about 10 nH, 50 nH, 100 nH, 150 nH, 500 nH, 1000 nH, etc. The stray inductance of each switch module may be less than, for example, about 200 nH. The stray inductance of each switch module may be, for example, about 100 nH to about 500 nH. The combination of a switch module and its respective bridge diode may be coupled in series with its respective bridge inductor.

[0043] Transformer 145 (or transformer T1) may include, for example, a transformer disclosed in U.S. Patent Application No. 15 / 365,094, subject "High Voltage Transformer," which is incorporated herein for any purpose.

[0044] For example, the duty cycle of a switch module can be adjusted by changing the duty cycle of switch module 161 and the switch signal Sig1, changing the duty cycle of switch module 162 and the switch signal Sig2, changing the duty cycle of switch module 163 and the switch signal Sig3, and changing the duty cycle of switch module 164 and the switch signal Sig4.

[0045] Each switch module 161, 162, 163, or 164 within the high-voltage pulsing power supply 105 may be switched individually, for example, or in conjunction with one or more of the other switch modules. For example, signal Sig1 may be the same signal as signal Sig3. As another example, signal Sig2 may be the same signal as signal Sig4. As yet another example, each signal may be independent of the others, and each switch module 161, 162, 163, or 164 may be controlled independently or separately from each other.

[0046] The high-voltage pulsing power supply and plasma system 100 do not need to include a conventional matching network, such as a 50Ω matching network, an external matching network, or a standalone matching network. In fact, the embodiments described in this document do not require a 50Ω matching network for tuning the switching power applied to the wafer chamber. Furthermore, the embodiments described in this document include a variable output impedance RF generator without a conventional matching network. This can make it possible to rapidly change the power drawn into the plasma chamber. Typically, tuning this matching network may take at least about 100 μs to about 200 μs. The power change can be made within 1 to 2 RF cycles, for example, within about 2.5 μs to about 5.0 μs at 400 kHz.

[0047] The high-voltage pulsing power supply 105 may be replaced, for example, by a half-bridge circuit having two switch modules. The high-voltage pulsing power supply 105 may supply power in, for example, multiple configurations. For example, as shown in Figures 1 and 24, a combination of multiple power supplies and energy storage capacitors may be used to supply power to a full bridge (or half bridge). As another example, as shown in Figures 7, 12, and 21, a combination of a single power supply and energy storage capacitor may be used to supply power to a full bridge (or half bridge).

[0048] In the droop control circuit 110, a droop resistor 186 may be connected in series with the droop inductor 187. The series connection between the droop inductor 187 and the droop resistor 186 may be arranged in parallel with the droop diode 183 and / or inductor 184, or across the droop diode 183 and / or inductor 184.

[0049] The droop diode 183 may include, for example, one or more diodes arranged in series or in parallel. The droop diode 183 is capable of passing currents greater than, for example, about 100 amperes at its rated value. The droop diode 183 is capable of passing currents greater than, for example, about 10, 100, 1000, 10000, etc. at its rated value.

[0050] Inductor 184 may include, for example, a physical inductor and / or represent parasitic inductance and / or stray inductance. Parasitic inductance and / or stray inductance may include, for example, the inductance of components between the high-voltage pulsing power supply 105 and the plasma chamber 106, and / or the inductance of the transformer 145. Inductor 184 may have an inductance of, for example, about 0.1 nH, 1 nH, 10 nH, 100 nH, 1 μH, or 10 μH. Inductor 184 may have an inductance of, for example, less than about 500 nH.

[0051] The inductance value of inductor 184 may be set, for example, so that the rising pulse has a good sinusoidal top. If the inductance value of inductor 184 is too small, the ring-up on the positive pulse may become too short, for example, and the appearance of steps within the positive pulse may be delayed. For example, if the inductance value of inductor 184 is too small, oscillations that cross the top of the positive pulse may be observed. For example, if the inductance value of inductor 184 is too large, there may not be enough time for the smooth sinusoidal top to complete, and the top of the sine wave will be cut off. For example, if the inductance value of inductor 184 is too large, the positive pulse may become large when the top is cut off by the transition to the falling pulse.

[0052] The droop control circuit 110 controls the voltage gradient on the transformer 145 so that the peak voltage occurs in the latter half of the pulse. The droop inductor 187 is excited during the negative voltage portion of the bipolar pulse, while the droop resistor 186 extracts energy from the droop inductor 187. The combination of the shape of the applied negative pulse and the droop resistor 186 causes the current in the droop inductor 187 to become balanced. This balanced current may have an inter-pulse ripple that is, for example, less than 1%, 5%, 20%, or 100% of its average value. The droop inductor may have an inductance that allows it to reach equilibrium earlier than the first 2, 5, 70, or 100 pulses during a pulse burst. The droop inductor 187 may have an inductance that allows the current through it to reach equilibrium earlier than 20 pulses. The current flows into the transformer 145 through the droop diode 183 and inductor 184 during the positive portion of the bipolar pulse.

[0053] Inductor 184 may have an inductance of, for example, approximately 0.1 nH, 3 nH, 100 nH, or 10 μH. This is typically set to less than 200 nH. Droop inductor 187 may have an inductance of, for example, approximately 1 μH, 10 μH, 100 μH, or 3000 μH.

[0054] The droop resistor 186 may have a resistance of, for example, approximately 0.01 Ω, 0.3 Ω, 30 Ω, or 100 Ω. This is typically set to less than 4 Ω.

[0055] The plasma chamber 106 may represent, for example, an ideal or effective circuit for a semiconductor processing chamber (e.g., a plasma deposition system, a semiconductor manufacturing system, a plasma sputtering system, a plasma etching system, etc.). The capacitance of capacitor 12 may represent, for example, the capacitance of an electrostatic chuck on which a semiconductor process wafer may be placed. The chuck may include, for example, a dielectric material (e.g., aluminum oxide or other ceramic material, and a conductor housed within the dielectric material). For example, capacitor 23 may have a small capacitance (e.g., about 10pF, 100pF, 500pF, 1nF, 10nF, 100nF, etc.).

[0056] Capacitor 13 may represent, for example, the sheath capacitance between the plasma and the wafer. Resistor 56 may represent, for example, the sheath resistance between the plasma and the wafer. Inductor 40 may represent, for example, the sheath inductance between the plasma and the wafer. Current source I2 may represent, for example, the ion current passing through the sheath. For example, capacitor 23 or capacitor 13 may have a small capacitance (for example, about 10pF, 100pF, 500pF, 1nF, 10nF, 100nF, etc.).

[0057] Capacitor 18 may represent, for example, the plasma sheath capacitance against the chamber wall. Resistor 57 may represent, for example, the resistance between the plasma and the chamber wall. Current source I1 may represent, for example, the ion current in the plasma. For example, capacitor 23 or capacitor 18 may have small capacitances (for example, about 10pF, 100pF, 500pF, 1nF, 10nF, 100nF, etc.).

[0058] The plasma chamber may include one or more electrodes that can be used to ignite and / or drive the plasma. One or more electrodes may be electrically coupled to a high-voltage pulsing power supply.

[0059] Figures 2A and 2B show the output waveform 205 at point 134 and the wafer waveform 210 at point 135 in an example circuit of a high-voltage pulsing power supply and plasma system 100. The wafer waveform 210 may represent, for example, the voltage on a wafer in a plasma chamber (e.g., a dielectric etching plasma chamber). Waveform 215 shows the switching logic of the SIG±2 switch module 162 and switch module 164. Waveform 220 shows the switching logic of the SIG±1 switch module 161 and switch module 163. As shown, the inter-pulse portion of the output waveform 205 has a negative slope, which causes the inter-pulse portion of the wafer waveform 210 to be nearly flat.

[0060] The output waveform 205 is generated, for example, with a charging voltage of 600V from the DC power supply 151, a positive pulse width of 450ns, and a negative pulse width of 1950ns. In this example, the droop inductor 187 is approximately 6μH, the droop resistor 186 has a resistance of 0.5Ω, and the inductor 184 has an inductance of approximately 16nH. This can reduce or mitigate voltage droop within the plasma chamber (e.g., on the wafer within the plasma chamber), as shown, for example, in the flat portion between the two positive pulses of the wafer waveform 210.

[0061] Figure 2B also shows an example of two high-voltage pulses. Each pulse of the wafer waveform 210 has a positive pulse portion 211 and a negative pulse portion 212. The positive pulse portion 211 is the part of the pulse where the voltage is greater than zero, and the negative pulse portion 212 is the part of the pulse where the voltage is below zero. The pulse may have a fast rise time (i.e., a steep positive slope) between the negative pulse portion 212 and the positive pulse portion 211. The pulse may also have a fast fall time (i.e., a steep negative slope) between the positive pulse portion 211 and the negative pulse portion 212. The fall time may be slower than the rise time, for example.

[0062] The positive pulse portion 211 may have, for example, a relatively flat upper portion (or at least a portion with a gentle rising and / or falling gradient). The positive pulse portion 211 may be of any length. The negative pulse portion 212 may have, for example, a relatively flat lower portion (or at least a portion with a gentle rising and / or falling gradient). The negative pulse portion 212 may be of any length. The negative pulse portion 212 may be longer than the positive pulse portion 211.

[0063] The relative height of the positive pulse portion 211 to the negative pulse portion 212 is the pulse amplitude. The time between consecutive positive pulse portions 211 is the pulse period, and the reciprocal of the pulse period is the pulse repetition frequency. The pulse waveform is neither a sine wave nor an RF waveform. In fact, the ideal pulse waveform for a wafer (e.g., wafer waveform 210) is more like a square wave than a sine wave. Furthermore, with a sine wave, the rise time and / or fall time cannot be made fast because the relatively flat upper portion and / or flat lower portion are long, but this is not necessarily true for a pulse waveform. Furthermore, with a sine wave, the lengths of the positive pulse portion 211 and the negative pulse portion 212 are approximately the same, but this is not necessarily true for a pulse waveform.

[0064] The output waveform 205 in Figure 2B shows an example 221 of inter-pulse droop. As shown in the figure, the inter-pulse droop is a negative slope of the negative pulse portion 212.

[0065] Lowering the output voltage can be achieved, for example, by adjusting the time constant so that the charging voltage remains nearly constant. This is sometimes called multi-state operation and involves a sequence of pulses with different voltages. Multi-state operation can be achieved, for example, by adjusting the positive and negative pulse widths, as shown in Figures 3A and 3B, which show the output waveform 305 at point 134 and the wafer waveform 310 at point 135. In Figure 3A, a positive pulse width of 50 ns and a negative pulse width of 350 ns are used. In Figure 3B, the positive pulse width is 90 ns and the negative pulse width is 2310 ns.

[0066] Multi-state operation can be achieved, for example, by increasing the value of the droop resistor 186. This is because a higher resistance value can lower the output voltage. In the waveform shown in Figure 3B, the droop resistor 186 is set to 6Ω, while 0.5Ω was used to generate the waveform in Figure 2B.

[0067] Figure 4 is a circuit diagram of an exemplary high-voltage pulsing power supply and plasma system 400. The droop resistor 186 of the plasma system 100 is replaced by a droop capacitor 486 in series with the droop inductor 187. The droop capacitor 486 may have capacitances of approximately 10mF, 25mF, 50mF, 100mF, 250mF, 500mF, 1000mF, 38F, 200F, etc. The droop capacitor 486 may, for example, extract energy from the droop inductor. While the droop resistor 186 dissipates energy as resistive losses, the droop capacitor 486 can convert energy into stored capacitive energy. This stored energy can, for example, increase the potential difference across the droop capacitor 486. This stored energy can be recovered by an energy recovery circuit (e.g., energy recovery circuit 701, active droop control circuit 1201, or energy compensation circuit 2101) so that the voltage across the droop capacitor 486 remains nearly constant during bursts. The energy recovery circuit may include, for example, a DC-DC converter that maintains the voltage over the droop capacitor 486 while delivering excess energy to a high-voltage pulsing power supply 105. When an energy recovery circuit is used, the value of the droop capacitor 486 may be less than approximately 100mF, 10mF, 100μF, 10μF, or 1μF. This value is typically set to less than approximately 30μF in a full-bridge topology and less than approximately 100μF in a half-bridge topology.

[0068] The output waveform 505 shown in Figures 5A and 5B is measured at point 134 of the high-voltage pulsing power supply and plasma system 400, and the wafer waveform 510 is measured at point 135 of an example circuit of the high-voltage pulsing power supply and plasma system 400. The wafer waveform 510 may, for example, show the voltage on the wafer in the plasma chamber. Waveform 515 shows the switching logic of the SIG±2 switch module 162 and switch 164. Waveform 520 shows the switching logic of the SIG±1 switch module 161 and switch 163. As shown, the inter-pulse portion of the output waveform 505 has a negative slope, which causes the inter-pulse portion of the wafer waveform 510 to be nearly flat.

[0069] The output waveform 505 and wafer waveform 510 may be generated, for example, by setting the charging voltage from the DC power supply 151 to 600V, the positive pulse width to 450ns, and the negative pulse width to 1950ns. An initial charge of -270V may be applied across the droop capacitor 486. In the examples shown in Figures 5A and 5B, the droop capacitor 486 may have a capacitance of approximately 200mF.

[0070] Figures 6A and 6B show the output waveform 605 at point 134 and the wafer waveform 610 at point 135. The waveform shown in Figure 6A has a positive pulse width of 50 ns and a negative pulse width of 350 ns. The waveform shown in Figure 6B has a positive pulse width of 90 ns, a negative pulse width of 2310 ns, and an initial charging voltage of -575 V on the droop capacitor.

[0071] Figure 7 is a circuit diagram of a high-voltage pulsing power supply and plasma system 700, which may include a power supply 705 coupled to the plasma chamber 106. The high-voltage pulsing power supply and plasma system 700 may include a droop control circuit 110 and / or an energy recovery circuit 701. Power supply 705 may be similar to the high-voltage pulsing power supply 105 and have a DC power supply 150 and an energy storage capacitor 155.

[0072] The energy recovery circuit 701 is coupled to the droop inductor 187 of the droop control circuit 110. The energy recovery circuit 701 may also be coupled to the DC power supply 150 and the energy storage capacitor 155. The energy recovery circuit 701 may include, for example, a DC-DC converter coupled between the droop control circuit 110 and the energy storage capacitor 155.

[0073] The energy recovery circuit 701 may include switch modules 731 and 732 arranged in a half-bridge configuration (full-bridge configuration or other bridge configurations may also be used). Each switch module 731, 732 may include its respective switch diodes 741, 742. The energy recovery circuit 701 may also include a transformer 715 coupled to switch modules 731 and / or 732. The transformer 715 may be inductively coupled to a rectifier bridge 730, which may be coupled to an energy storage capacitor 155 via an energy recovery inductor 706 and / or an energy recovery diode 710. The energy recovery diode 710 may allow charge from, for example, a droop capacitor 720 and / or a droop capacitor 725 to flow and charge the energy storage capacitor 155. The values ​​of each element in the energy recovery circuit may be set to allow the voltages on droop capacitors 720 and 725 to change in a time shorter than (for example) 2 pulses, 20 pulses, or 200 pulses.

[0074] The energy recovery inductor 706 may have a small inductance, for example. The energy recovery inductor 706 may have an inductance smaller than approximately 1 nH, 10 nH, 50 nH, 100 nH, 150 nH, 500 nH, 1000 nH, etc. The energy recovery inductor 706 may include the inductance of, for example, the rectifier bridge 730, the transformer 715, the switch module 731, and / or the switch module 732.

[0075] The switch modules 731 and / or 732 can control the amount of energy drawn from the droop inductor 187, for example, by switching them on and off. This can be done, for example, by adjusting the duty cycle of the switch modules 731 and / or 732. This can be done, for example, based on feedback from one or more sensors monitoring the voltage at capacitance 12.

[0076] The energy recovery circuit 701 may, for example, transfer energy from the droop inductor 187 to charge the energy storage capacitor 155. The energy recovery circuit 701 may be coupled to both ends of the droop capacitors 720 and / or 725.

[0077] Figures 8A and 8B show the output waveform 805 at point 134 and the wafer waveform 810 at point 135 in an example circuit of a high-voltage pulsing power supply and plasma system 700. As shown, the inter-pulse portion of the output waveform 805 has a negative slope, which causes the inter-pulse portion of the wafer waveform 810 to be nearly flat.

[0078] In this example, output generation may be performed with a charging voltage of 600V from a DC power supply, a positive pulse width of 450ns, and a negative pulse width of 1950ns. In this example, the switching frequencies of switch modules 731 and 732 are set to 250kHz. Typical operating frequencies may be higher than 1kHz, 10kHz, 100kHz, or 3MHz. In this example, each switch is closed for approximately 1.65μs, resulting in a duty cycle of approximately 2.5%. In this example, an initial charging voltage of approximately -135V is applied across droop capacitors 720 and / or 725, and the sum of the initial charging voltages across these two capacitors is -270V. In this example, the capacitance of each droop capacitor 720 and / or 725 is approximately 25μF, but other values ​​are also usable, for example, values ​​smaller than approximately 1μF, 33μF, 500μF, or 3mF. This specific capacitance value may be selected to set both the plasma current ripple and the rate at which the wafer voltage can be regulated through the operation of the energy recovery circuit. Typical regulation times may be, for example, longer than about 0.1 μs, 1 ms, or about 10 minutes. This initial electromotive force allows the output voltage to reach equilibrium rapidly, while the energy recovery circuit duty cycle maintains equilibrium.

[0079] Figure 9 shows the output waveform 905 at point 134 and the wafer waveform 910 at point 135 in an example circuit of a high-voltage pulsing power supply and plasma system 700. In this example, no initial electromotive force is applied to the droop capacitors 720 and / or 725. In this example, the output voltage still reaches equilibrium.

[0080] Figures 10A and 10B show the output waveform 1005 at point 134 and the wafer waveform 1010 at point 135 in an example circuit of a high-voltage pulsing power supply and plasma system 700. In this example, the values ​​of the circuit are the same as those used to generate the waveforms shown in Figures 8A and 8B, except that in Figure 10A the timing is 50 ns for the positive pulse and 350 ns for the negative pulse, and in Figure 10B the timing is 90 ns for the positive part of the pulse and 2310 ns for the negative part of the pulse. In this example, the energy recovery circuit duty cycle is reduced to 15%. The energy recovery circuit duty cycle may be in any range from 0% to 100%, which is typical for DC-DC converters.

[0081] Figure 11 shows the output waveform 1105 at point 134 and the wafer waveform 1110 at point 135 in an example circuit of a high-voltage pulsing power supply and plasma system 700. In this example, the output voltage is switched between a high-voltage burst 1120 of approximately 27.5 μs, a multi-state burst 1125 of approximately 32.5 μs, and a high-voltage burst 1130 of approximately 27.5 μs. This transition is simply achieved by using an energy recovery circuit to set / program the voltage across droop capacitors 720 and / or 725. Increasing the voltage across these capacitors can lead to lower voltage and / or multi-level operation, while decreasing the voltage across these capacitors can lead to higher voltage operation. By adjusting the voltage across these capacitors, it is possible to use an energy recovery circuit (i.e., a DC-DC converter) to generate any rough combination of output voltages that form any desired time-dependent pattern. During the transition from high-voltage burst 1120 to multi-state burst 1125, the transformer flux may swing negative over a few transition bursts 1125A. For example, the multi-state positive pulse width may be adjusted and / or the multi-state negative pulse width may be reduced to prevent the transformer from saturating during this transition and reducing the amount of negative flux injected into the transformer core.

[0082] Figure 12 is a circuit diagram of a high-voltage pulsing power supply and plasma system 1200 having an active droop control circuit 1201. The active droop control circuit 1201 may also include, for example, an energy recovery element (e.g., an energy recovery inductor 1225 and a diode 1226) that recovers energy from the droop inductor 187 to the energy storage capacitor 156.

[0083] The high-voltage pulsing power supply and plasma system 1200 includes an active droop control circuit 1201 and a high-voltage pulsing power supply 705 coupled with a plasma chamber 106.

[0084] The active droop control circuit 1201 may include, for example, a droop inductor 187, which is coupled in series with a droop capacitor 486 and a second droop inductor 1205. The total droop inductance may be evenly divided between the droop inductors 187 and 1205, or unevenly divided between them. If an even division is chosen, the design and construction of each individual inductor may be simplified. A switch circuit (e.g., a half-bridge switch circuit or a full-bridge switch circuit) may be coupled across the droop capacitor 486. The switch circuit may also be coupled to a transformer 1210.

[0085] The active droop control circuit 1201 may include, for example, switch modules 1215, 1216, 1217, 1218, a transformer 1210, a diode rectifier bridge 1220, an energy recovery inductor 1225, and / or an energy recovery diode 1226. The diode rectifier bridge 1220 may be coupled, for example, to the energy recovery inductor 1225 and the transformer 1210, or between the energy recovery inductor 1225 and the transformer 1210. The energy recovery inductor 1225 may be coupled to an energy storage capacitor 156 which is part of the power supply 705.

[0086] By controlling the timing of each switch in the active droop control circuit 1201, it is possible to extract charge from and / or add charge to the droop capacitor 486. The active droop control circuit 1201 may be, or include, any converter that moves energy from the droop capacitor 486 to the energy storage capacitor 156, or from the energy storage capacitor 156 to the droop capacitor 486.

[0087] The active droop control circuit 1201 may include, for example, any of various forms of DC-DC converters. The active droop control circuit 1201 may include, for example, a set of switches arranged in a bridge configuration, a transformer, a rectifier stage, and a filter inductor. An exemplary function of the active droop control circuit 1201 may be to adjust the voltage on the droop capacitor 486. This may be done, for example, on the required time scale to generate a desired wafer voltage waveform and / or plasma voltage waveform.

[0088] The value of the droop capacitor 486 may be approximately 10mF, 1mF, 20μF, or less than 1μF. For example, the value of the droop capacitor 486 may be less than approximately 100μF. The specific value of the droop capacitor 486 may be selected to enable and / or facilitate the function of the active droop control circuit 1201, which adjusts the voltage across the droop capacitor 486 on the required time scale. The adjustment time scale may be longer than approximately 1μs, 1ms, or 1 hour. The smaller the inductance value of the droop capacitor 486, the faster the output voltage can be adjusted, for example, thereby enabling more rapid adjustment of the ion energy distribution in the plasma and allowing for finer tuning of the composite ion energy distribution in the plasma, including the sum of the individual ion energy distributions in the plasma.

[0089] The time scale over which the active droop control circuit 1201 adjusts the voltage on the droop capacitor 486 may be shorter than 2 pulses, 20 pulses, or 200 pulses, each pulse may have a positive and a negative portion, which together last over 100 ns, 1 μs, 2.5 μs, 100 μs, or 1 ms. The time scale over which the active droop control circuit 1201 adjusts the voltage on the droop capacitor 486 may be considered short compared to the typical time scale of 100 ms to 1 s over which a DC-DC converter typically operates / adjusts the voltage.

[0090] By adjusting the voltage across the droop capacitor 486, the active droop control circuit 1201 can, for example, control the ion energy distribution in the plasma and / or control the voltage droop between pulses on the wafer. Either or both of these can be performed, for example, in real time, within approximately 100 μs, 10 μs, 5 μs, 1 μs, 500 ns, 250 ns, 100 ns, etc. It may be advantageous to rapidly and / or slowly change the voltage across the droop capacitor 486. A slow change allows for a relatively uniform ion energy distribution function per pulse, while a rapid change allows for very different ion energy distribution functions per pulse. Whether the voltage across the chuck capacitance (e.g., capacitor 12) is changed slowly or rapidly, the resulting cumulative ion energy distribution function may be the same. In contrast, rapidly changing the voltage across the droop capacitor 486 can result in a cumulative ion energy distribution function that is entirely different from and / or entirely different from those that could be realized by any individual pulse's ion energy distribution function.

[0091] Figure 13 shows a waveform with a sequence of pulses generated by a high-voltage pulsing power supply and plasma system 1200. Figure 14A shows magnified views of the two pulses, and Figure 14B shows the various control waveforms used by each switch to generate the waveforms shown in Figures 13 and 14A.

[0092] For example, output waveform 1305 is the waveform measured at point 134, and wafer waveform 1310 is the corresponding waveform measured at point 135. Output waveform 1305 shows the voltage at capacitor 12. Wafer waveform 1310 shows the voltage on the wafer in the plasma chamber. Control waveform 1420 shows the SIG±2 switching logic, which opens and closes switch modules 162 and 164, which, when closed, generates a positive pulse portion 1305. Control waveform 1415 shows the SIG±1 switching logic, which opens and closes switch modules 161 and 163, which generates a negative pulse portion 1315. Energy recovery waveform 1425 shows a switching logic of SIG±3, which opens and closes ER switches 1215 and 1217, while energy recovery waveform 1430 shows a switching logic of SIG±4, which opens and closes ER switches 1216 and 1218.

[0093] The positive pulse portions of waveforms 1305 and 1310 correspond to the closing of switches 161 and 163 by control waveform 1415, and the opening of switches 162 and 164 by control waveform 1420. The peak and minimum voltages of the positive and negative pulse portions of waveforms 1305 and 1310 may be proportional to the duration of either or both of the on-times of waveform 1425 and / or waveform 1430. The durations of the on-times of waveforms 1425 and 1430 may be used to set the voltage on the droop capacitor 486. By changing the durations of the on-times of waveforms 1425 and 1430, it is possible to change the voltage on the droop capacitor 486.

[0094] Furthermore, the negative pulse portion of the output waveform 1305 has a negative slope or droop, while the negative pulse portion of the wafer waveform 1310 is almost flat. In this example, the output waveform 1305 and wafer waveform 1310 may be generated by the plasma system 1200, for example, with a charging voltage of 600V from the DC power supply 151, a positive pulse width of 450ns, and a negative pulse width of 1950ns.

[0095] The waveforms shown in Figures 13, 14A, and 14B were generated using a droop capacitor with a capacitance less than approximately 10 μF. For example, the transformer 1201 may have a small winding ratio, such as 3:1 or 2:1, or it may be set as high as 10:1 or 40:1. The specific value of the selected winding ratio sets, to some extent, both the ripple of the current flowing through the energy recovery circuit and the rate of voltage regulation on the droop capacitor 486 made possible by the active droop control circuit 1201. The higher the winding ratio, the larger the current ripple and the faster the rate of voltage regulation on the droop capacitor 486 made possible by the active droop control circuit 1201. The switching frequency of the switch modules 1215, 1216, 1217, and 1218 may be approximately 200 kHz. An operating frequency of approximately 1 kHz to approximately 10 MHz may be selected. As another example, the switches in switch modules 1215, 1216, 1217, and 1218 may be closed for approximately 1.98 μs and / or have a duty cycle of approximately 79.2%. The selected duty cycle may be in the range of 0% to 100%, thereby enabling the active droop control circuit 1201 to recover its minimum and maximum energy levels anywhere. The active droop control circuit 1201 may be any form of DC-DC converter.

[0096] Figure 12 shows a full-bridge topology. Various other DC-DC converter topologies are also possible. DC-DC converter topologies may be designed to allow rapid adjustment of the voltage across the droop capacitor 486 (e.g., in less than 100 μs, 10 μs, or 1 μs). DC-DC converter topologies may also allow very slow adjustment of the voltage across the droop capacitor 486 (e.g., over a period of 1 s, 1000 s, or longer than a day). Typical operation of the active droop control circuit 1201 allows the voltage across the droop capacitor 486 to formulate any required waveform on any time scale, from very fast to very slow. Depending on the plasma process, rapid voltage adjustment may be required, while depending on the plasma process, adjustment of plasma conditions may be required slowly over hours or days.

[0097] The active droop control circuit 1201 can, for example, enable operation within a wafer voltage range without changing the input charging voltage. For example, by changing the positive and negative pulse widths of switch modules 1215, 1216, 1217, and 1218, and / or the duty cycle of switch modules 1215, 1216, 1217, and 1218, it is possible to increase the duration of time the wafer voltage is negative and / or increase the output voltage. Figure 15A shows a wafer waveform 1510 in which a wafer voltage of 1 kV is generated by the plasma system 1200, with a positive pulse width of 85 ns, a negative pulse width of 2315 ns, and an energy recovery pulse width of 300 ns from switch modules 1215, 1216, 1217, and 1218. Figure 15B shows the wafer waveform 1510 with a 4kV wafer voltage generated by the plasma system 1200, where the positive pulse width from switch modules 1215, 1216, 1217, and 1218 is 200ns, the negative pulse width is 2200ns, and the energy recovery pulse width is 730ns.

[0098] A process for generating the waveform shown in Figure 14A using the logic represented by the waveform in Figure 14B is also disclosed. For example, at a first time point, the process may include the step of closing a first switch module (e.g., switch module 162 and / or switch module 164) of the high-voltage pulsing power supply 705 and opening a second switch module (e.g., switch module 161 and / or switch module 163) to generate a positive pulse portion 211 of the first high-voltage pulse 1305. The positive pulse portion may have, for example, an amplitude greater than about 1 kV.

[0099] At approximately the first point in time or shortly thereafter, the process may include the step of closing a third switch module of the energy recovery circuit 2101 (e.g., switch module 1216 and / or switch module 1218) and opening a fourth switch module (e.g., switch module 1215 and / or switch module 1217).

[0100] At a second time point following the first time point, the process may include, for example, opening a first switch module (e.g., switch module 162 and / or switch module 164) and closing a second switch module (e.g., switch module 161 and / or switch module 163) to generate a negative pulse portion 212 of the first high-voltage pulse.

[0101] At a third time point following the second time point, the process may include, for example, the step of opening a third switch module.

[0102] At a fourth time point following the third time point, the process may include, for example, the step of closing the first switch module and opening the second switch module to generate another positive pulse portion (with an amplitude greater than approximately 1 kV) of the second high-voltage pulse.

[0103] At approximately the fourth point in time or shortly thereafter, the process may include, for example, the step of closing the fourth switch module at approximately the fourth point in time.

[0104] At a fifth time point following the fourth time point, the process may include, for example, the step of opening the first switch module and closing the second switch module to generate the negative pulse portion of the second high-voltage pulse.

[0105] Figure 16A shows the output waveform 1600 at point 134 and the wafer waveform 1610 at point 135 in an example circuit of a high-voltage pulsing power supply and plasma system 1200. In this example, the output waveform 1600 and wafer waveform 1610 have four different voltage states (e.g., a first state 1605, a second state 1610, a third state 1615, and a fourth state 1620), which are controlled by changing the pulse width and / or duty cycle of each switch in the active droop control circuit 1201, and / or the pulse width of the pulses generated by the power supply 705, and / or the pulse width driving each switch in the energy recovery circuit. Energy recovery control waveform 1625 controls the switching logic of SIG±3, which opens and closes ER switches 1215 and 1217, while energy recovery waveform 1630 shows the switching logic of SIG±4, which opens and closes ER switches 1216 and 1218 (ER stands for energy recovery).

[0106] The first state 1605 has, for example, a duration of about 22.5 μs and a negative voltage of about -10 kV. The first state 1605 can be generated, for example, by a 450 ns positive pulse width (+PW) and a 1950 ns negative pulse width (-PW) from the power supply 705, and a symmetrical 1980 ns pulse width at about 200 kHz from the active droop control circuit 1201.

[0107] The second state 1610 has, for example, a duration of approximately 22.5 μs and a negative voltage of approximately -7.5 kV. The second state 1610 can be generated by a 320 ns positive pulse width (+PW) and a 2080 ns negative pulse width (-PW) from the power supply 705, as well as a symmetrical 1200 ns pulse width at approximately 200 kHz from the active droop control circuit 1201.

[0108] The third state 1615 has, for example, a duration of approximately 22.5 μs and a negative voltage of approximately -5 kV. The third state 1615 can be generated by a 215 ns positive pulse width (+PW) and a 2185 ns negative pulse width (-PW) from the power supply 705, as well as a symmetrical 1020 ns pulse width at approximately 200 kHz from the active droop control circuit 1201.

[0109] The fourth state 1620 has, for example, a duration of approximately 22.5 μs and a negative voltage of approximately -2.5 kV. The fourth state 1620 can be generated by a 115 ns positive pulse width (+PW) and a 2285 ns negative pulse width (-PW) from the power supply 705, as well as a symmetrical 900 ns pulse width at approximately 200 kHz from the active droop control circuit 1201.

[0110] The generation of various other voltage states with different durations and voltages can also be achieved by changing the pulse width and / or duty cycle of each switch in the active droop control circuit 1201 and / or the pulse width of the pulses generated by the power supply 705. Various voltage states can also be generated by adjusting the DC power supply 151.

[0111] Figure 17A shows two pulses within the first state 1605, a magnified view of the waveform shown in Figure 16A around 20 μs, and simultaneously shows control waveform 1415, control waveform 1420, energy recovery waveform 1425, and energy recovery waveform 1430.

[0112] Figure 17B shows two pulses within the second state 1610, a magnified view of the waveform shown in Figure 16A around 40 μs, and simultaneously shows control waveform 1415, control waveform 1420, energy recovery waveform 1425, and energy recovery waveform 1430.

[0113] Figure 17C shows two pulses within the third state 1615, a magnified view of the waveform shown in Figure 16A around 60 μs, and simultaneously shows control waveform 1415, control waveform 1420, energy recovery waveform 1425, and energy recovery waveform 1430.

[0114] Figure 17D shows two pulses within the fourth state 1620, a magnified view of the waveform shown in Figure 16A around 80 μs, and simultaneously shows control waveform 1415, control waveform 1420, energy recovery waveform 1425, and energy recovery waveform 1430.

[0115] To generate a desired output waveform, the timing of all control waveforms may be continuously adjusted over all relevant or required time ranges. The timing precision of the waveform adjustment may be finer than 1 s, 1 ms, 1 μs, 1 ns, or less, as needed to generate the desired waveform. Typically, a specific waveform or waveform pattern will be selected to optimize a particular plasma process (e.g., increasing the plasma etching rate, controlling the width of the etched feature, controlling the aspect ratio of the etched feature, controlling the mask etching rate, etc.). By adjusting the waveform, it is possible to control various plasma processes and features. By adjusting the output waveform, it is possible to adjust the resulting ion energy distribution function. By adjusting the voltage across the droop capacitor 486 and all switch timings, it is possible to adjust the output waveform, output current, resulting ion energy distribution function, and any number of specific plasma and / or etched features. In particular, the present invention enables the adjustment of plasma parameters and etching parameters (e.g., ion energy distribution function) over a wide, often continuous operating space. This can be done in a steady-state manner if all pulses are the same for a particular ion energy distribution function, or by modulating the output pulses so that an aggregated waveform with a particular aggregated ion energy distribution function is generated. During any particular etching process, it may be advantageous to continuously optimize the ion energy distribution function over the entire etching process.

[0116] Figure 18 shows the ion energy distribution function of ions in the plasma chamber 106 of the plasma system 1200 with the pulse and configuration described in Figure 17B.

[0117] Figure 19 shows the ion energy distribution of ions in the plasma chamber 106 of the plasma system 1200 with the pulse and configuration described in Figure 17A.

[0118] Figure 20A shows the lower limit of the energy distribution function shown in Figure 19, and Figure 20B shows the upper limit of the energy distribution function shown in Figure 19. The plasma system 1200 is capable of generating an ion energy distribution that is nearly flat for various ion energies, which can lead to the wafer voltage remaining nearly constant over long periods of time.

[0119] Figure 21 is a circuit diagram of a high-voltage pulsing power supply and plasma system 2100 having a droop control circuit 2150 and an energy control circuit 2101. In the droop control circuit 2150, an inductor 2145 is coupled in series to a diode 2140. The rising pulse from the secondary side of the transformer 145 passes through the diode 2140 and inductor 2145 to the plasma chamber 106. Figure 21 shows the case where the droop control element and energy recovery element are located on the secondary side of the transformer. In general, the droop control element and the active droop control circuit 1201 may be located on either the primary side or the secondary side of the transformer. The overall function of the element group is the same, but the specific values ​​used are scaled according to the winding ratio of the transformer, with the inductor being larger by a square multiple of the winding ratio and the capacitor being smaller by one square of the winding ratio.

[0120] The series connection of the droop inductor 2120 and the droop capacitor 2130 may be parallel to the diode 2140 and / or inductor 2145, or across the diode 2140 and / or inductor 2145. The droop control circuit 2101 controls the voltage gradient on the transformer 145 so that the peak voltage occurs in the latter half of the pulse. The droop inductor 2120 is excited during the negative voltage portion of the bipolar pulse, reaches equilibrium when a fully charged voltage is present on the inductor 2145 or plasma chamber 106, and during the positive pulse, energy is extracted from the droop inductor 2120 at approximately the same rate as energy is acquired. During the positive pulse of the bipolar pulse, current flows from the secondary side of the transformer 145 through the diode 2140 and inductor 2145 to the plasma chamber 106.

[0121] The capacitor 2130 may be a resistor or an inductor. If the capacitor 2130 is a capacitor, it may be coupled to an active energy recovery circuit that adjusts the voltage across the capacitor 2130 in order to select a desired output voltage waveform.

[0122] The energy compensation circuit 2101 is coupled to the secondary side of the transformer 145 and to the energy storage capacitor 156. The energy compensation circuit 2101 includes, for example, an energy recovery diode 2105 and an energy recovery inductor 2110. The energy recovery diode 2105 and the energy recovery inductor 2110 may be coupled to the secondary side of the transformer 145 via a diode 2115 and a droop control circuit. The value of the inductor 2105 may be greater than 1 μH, 10 μH, 100 μH, or 10 mH.

[0123] Figure 22 shows the ion energy distribution of ions in the plasma chamber 106 of the plasma system 2100 (or any of the plasma systems disclosed herein).

[0124] Figure 23A shows the lower limit of the ion energy distribution shown in Figure 22, and Figure 23B shows the upper limit of the ion energy distribution shown in Figure 22. Plasma system 2100 (or any plasma system disclosed herein) is capable of generating an ion energy distribution that is nearly flat over a range of ion energies (e.g., nearly flat over a significant portion of ion energies) and has peaks in a narrow band of ion energies, which can lead to a nearly constant wafer voltage over long periods. By adjusting various droop control elements and energy recovery elements, it is possible to generate any number of potential ion energy distribution functions. Maintaining specific plasma parameters, sweeping a range of plasma parameters from edge to edge, or controlling a range of plasma parameters is possible by adjusting specific elements in real time.

[0125] Figure 24 is a schematic diagram of a high-voltage pulsing power supply and plasma system 2400 having an active droop control circuit 2401. The high-voltage pulsing power supply and plasma system 2400 includes the active droop control circuit 2401 and a high-voltage pulsing power supply 105 coupled to a plasma chamber 106. The active droop control circuit can operate to generate various output waveforms and various ion energy distribution functions, similar to the operation of the droop control circuit and active energy recovery circuit described above. Figure 24 shows yet another case of this generation.

[0126] The active droop control circuit 2401 may be coupled, for example, to the droop inductor 187 on the primary side of the transformer 145. The active droop control circuit 2401 can add charge to the droop capacitor 486 and / or remove charge from the droop capacitor 486. When switch 2408 is closed and switch 2410 is open, the charge stored in the droop capacitor 486 can dissipate into the resistor 2406. The resistor 2406 may have a resistance of, for example, about 0.1Ω, 3Ω, or 367Ω.

[0127] When switch 2408 is open and switch 2410 is closed, the droop capacitor 486 can be charged from the voltage source 2412 through the inductor 2404. The voltage source 2412 may have a voltage of, for example, approximately 0V, 100V, 500V, or 5000V. The voltage source 2412 may provide a voltage that is always within approximately 10V, 300V, or 5000V of the DC power supply 150 and / or DC power supply 151.

[0128] Figure 25 is a flowchart of an exemplary process 2500 for controlling the ion energy distribution on a wafer. In block 2505, multiple high-voltage pulses (e.g., bursts of pulses) are introduced into the plasma by a high-voltage pulser. Process 2500 may be operable for plasma systems 2400, 2100, and / or 1200.

[0129] In block 2510, the ion energy distribution on the wafer may be measured, estimated, or calculated. Estimating the ion energy distribution on the wafer can be done by measuring the output voltage from the pulsing power supply, the voltage at capacitor 12, the output current of the pulsing power supply, and / or the plasma density in the chamber.

[0130] In block 2515, if there is an ion energy distribution on the wafer, it may be determined whether it is within an acceptable range. If it is within an acceptable range, process 2500 may return to block 2505. If it is not within an acceptable range, process 2505 may proceed to block 2520.

[0131] In block 2520, adjustment of the ion energy distribution may be determined based on the measured ion energy distribution and / or a specified or desired ion energy distribution.

[0132] In block 2525, the duty cycle and / or pulse width (duration of opening / closing) of the energy recovery switch may be adjusted. The process 2500 may then return to block 2505.

[0133] Various other control processes for this system are also envisioned. Parameters that can be measured and / or adjusted using some / any form of real-time feedback and control include waveforms of all aspects of the output voltage and current, any and / or all switch timings, values of various components, ion energy distribution functions, and any number of plasma parameters and / or etching parameters. For example, by controlling the voltage across the droop capacitor 720 and / or the droop capacitor 725, it is possible to maintain a specific etching rate, aspect ratio, mask erosion rate, and / or feature size. For example, by monitoring and setting the output voltage waveform in real time, it is possible to maintain a specific ion energy distribution function or to establish / wipe out a specific set of ion energy distribution functions. The selected ion energy distribution function may be selected to optimize one or a number of specific etching parameters (such as etching rate, aspect ratio, and / or feature size, etc.). For example, it is possible to control the mask erosion rate by changing the droop rate.

[0134] FIG. 26 shows an exemplary waveform having two ideal pulse bursts, namely, a first burst 2605 and a second burst 2606. One burst may include a plurality of pulses 2610. The burst duration is the time (T on ) that the burst is on, and the time (T off ) that the burst is off. The pulse width (P Width ) is the time that the pulse is on. The pulse period (P Period ) is the time that the pulse is on or off. The duty cycle is the on time (T on ) divided by the burst duration: DC = T on / (T on + T off ) and may be expressed as such. The burst repetition frequency is the reciprocal of the burst period: f burst = 1 / (T on + T offIt can be expressed as ). The pulse repetition frequency is the reciprocal of the pulse period: f pulse = 1 / P period It can be expressed as follows.

[0135] A positive waveform has pulse bursts where the minimum voltage is V0 and the pulse amplitude is V1, both above zero. A negative waveform has pulse bursts where the minimum voltage is V0 and the pulse amplitude is V1, both below zero. A bipolar waveform has pulse bursts where the minimum voltage is V0 (below zero) and the pulse amplitude is V1 (above zero).

[0136] The computer system 2700 shown in Figure 27 can be used to implement any embodiment of the present invention. For example, the computer system 2700 can be used to perform any or all of the processes 2500 and / or all of the feedback and control processes described above. As another example, the computer system 2700 can perform all of the calculations, identifications, and / or decisions described herein. The hardware elements of the computer system 2700 may be electrically coupled via bus 2705 (or otherwise communicate as needed). The hardware elements may include one or more processors 2710, one or more input devices 2715, and one or more output devices 2720, wherein the one or more processors 2710 may include, but are not limited to, one or more general-purpose processors and / or one or more dedicated processors (e.g., digital signal processing chips, graphics accelerator chips, and / or the like), the one or more input devices 2715 may include, but are not limited to, a mouse, keyboard, and / or the like, and the one or more output devices 2720 may include, but are not limited to, a display device, printer, and / or the like.

[0137] The computer system 2700 may further include (and / or communicate with) one or more storage devices 2725, one or more storage devices 2725 may, but not limited to, include local storage and / or network-accessible storage, and / or, but not limited to, disk drives, drive arrays, optical storage devices, solid-state storage devices (e.g., random access memory ("RAM") and / or read-only memory ("ROM") (these may be programmable, flash-updatable, and / or similar)). The computer system 2700 may also include a communication subsystem 2730, the communication subsystem 2730 may, but not limited to, a modem, a network card (for wireless or wired), an infrared communication device, a wireless communication device and / or a chipset (e.g., a Bluetooth device, an 802.6 device, a Wi-Fi device, a WiMAX device, a cellular communication device, etc.) and / or similar. The communication subsystem 2730 may enable data exchange with a network (for example, the network described later) and / or any other device described in this document. In many embodiments, the computer system 2700 further includes working memory 2735, which may include a RAM device or a ROM device as described above.

[0138] The computer system 2700 may also include software elements, which are currently illustrated as being located in working memory 2735, and include an operating system 2740 and / or other code, for example, one or more application programs 2745, the one or more application programs 2745 may include computer programs of the present invention and / or may be designed to implement the method of the present invention as described herein and / or to constitute a system of the present invention. For example, one or more procedures described with respect to the above-described method may be implemented as code and / or instructions executable by a computer (and / or a processor in the computer). These sets of instructions and / or code may be stored in a computer-readable storage medium (for example, the storage device 2725 described above).

[0139] In some cases, the storage medium may be incorporated into the computer system 2700 or may communicate with the computer system 2700. In another embodiment, the storage medium may be separate from the computer system 2700 (for example, it may be a removable medium such as a compact disk) and / or may be provided in the form of an installation package, so that the storage medium can be used to program a general-purpose computer with the instructions / code stored therein. These instructions may be in the form of executable code that can be executed on the computer system 2700 and / or in the form of source code and / or installable code that becomes executable code when compiled and / or installed on the computer system 2700 (for example, using one of various commercially available compilers, installation programs, compression / decompression utilities, etc.).

[0140] The above general descriptions and related optimization / workspace descriptions may substantially apply to all circuits disclosed herein, or to all drawings of one or another form. For example, if a short positive pulse can reset the system and cancel the accumulation of charge on the wafer due to the previously flowing ionic current, if the current in a droop inductor (e.g., droop inductor 187) can set a voltage on the wafer and / or reduce, eliminate, or reverse any voltage droop, if the current can be set by balancing the energy flowing into the droop inductor with the energy flowing out of the droop inductor (e.g., by balancing the positive volts-seconds and negative volts-seconds across the inductor), and / or if the nature of the energy recovery circuit is active or passive, if the net energy balance between the energy flowing into the droop inductor and the energy flowing out of the droop inductor can be set by the energy recovery circuit.

[0141] Unless otherwise specified, the word "substantially" means within 5-10% of the stated value or within manufacturing tolerances. Unless otherwise specified, the word "about" means within 5-10% of the stated value or within manufacturing tolerances.

[0142] The conjunction "or" is inclusive.

[0143] Terms such as "first," "second," and "third" are used to distinguish each element and are not used to indicate a specific order of those elements unless otherwise specified or unless the order is explicitly indicated or required.

[0144] Numerous specific details are provided to ensure a thorough understanding of the claims. However, as those skilled in the art will understand, it is possible to implement the claims without these specific details. Furthermore, in some cases, methods, apparatus, or systems that would be well known to those skilled in the art are not described in detail to avoid ambiguity of the claims.

[0145] Some parts are presented as algorithms or symbolic representations of actions for data bits or binary digital signals stored in computing system memory (e.g., computer memory). These algorithmic descriptions or representations are examples of techniques used by those skilled in the field of data processing to communicate their work to others skilled in the field. An algorithm is a consistent sequence of actions or similar processes that lead to a desired result. In this context, the actions or processes involve the physical manipulation of physical quantities. Typically, but not always, such quantities may take the form of electrical or magnetic signals that can be stored, transferred, combined, compared, or otherwise manipulated. It has sometimes been found convenient to refer to such signals, primarily for common use, as bits, data, values, elements, symbols, characters, terms, numbers, digits, etc. However, naturally, all these and similar terms should be associated with the appropriate physical quantities and are merely convenient labels. Unless otherwise specified, throughout the discussion herein, the terms “processing,” “computing,” “calculating,” “determining,” and “identifying” should be understood to refer to the actions or processes of a computing device (e.g., one or more computers or similar electronic computing devices) that manipulate or transform data represented as actual electronic or magnetic quantities within the memory, registers, or other information storage devices, transmission devices, or display devices of a computing platform.

[0146] The one or more systems described are not limited to any particular hardware architecture or hardware configuration. A computing device may encompass any suitable component configuration that outputs conditioned results for one or more inputs. Suitable computing devices include multipurpose microprocessor-based computer systems that access stored software to program or configure computing systems ranging from general-purpose computing devices to dedicated computing devices implementing one or more embodiments of the invention. Any suitable programming language, scripting language, or other type of language, or combination of languages ​​may be used to implement the included teachings in the form of software used to program or configure the computing device.

[0147] Embodiments of the disclosure method may be implemented in the operation of such computing device. The order of the blocks shown in the above example may be changed, for example, by rearranging the order of the blocks, combining blocks, and / or dividing blocks into subblocks. Several blocks or processes may be executed in parallel.

[0148] The use of “adapted to” or “configured to” is intended to be open and inclusive, not precluding any device adapted or configured to perform additional tasks or steps. Furthermore, the use of “based on” is intended to be open and inclusive, in that a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may actually be based on additional conditions or values ​​beyond those stated conditions or values. The included headings, lists, and numbering are for illustrative purposes only and are not intended to be restrictive.

[0149] While the subject matter of the present invention has been described in detail with respect to specific embodiments, it is naturally possible for those skilled in the art to easily generate variations, modifications, and equivalents of such embodiments by understanding the above. Therefore, it is naturally necessary to understand that this disclosure is provided for illustrative purposes only and not limitation, and does not exclude the inclusion of such modifications, modifications, and / or additions to the subject matter of the present invention, as will be readily apparent to those skilled in the art. [Note 1] A high-voltage pulsing power supply system, DC power supply, A switch circuit electrically coupled to the DC power supply, the switch circuit comprising a plurality of switch modules arranged in a full-bridge configuration, the switch circuit generating a plurality of pulses having a positive pulse portion, a negative pulse portion, and an amplitude greater than approximately 10kV, It is a transformer, Transformer core and The primary winding wound around the transformer core, The secondary winding wound around the transformer core, The transformer includes, A droop control circuit electrically coupled to the switch circuit and the primary winding, wherein the droop control circuit is A droop diode electrically coupled in series between the switch circuit and the primary winding, wherein the negative pulse portion of the plurality of pulses can pass from the switch circuit to the primary winding of the transformer, A droop inductor and a droop element arranged in series across the droop diode, wherein the negative pulse portion of the plurality of pulses allows the pulses to pass from the switch circuit to the primary winding of the transformer, and stores energy from the negative pulse portion of the plurality of pulses. The droop control circuit includes, The output is electrically coupled to the secondary winding and outputs a plurality of pulses having a substantially flat negative pulse portion, A high-voltage pulsing power supply system including this. [Note 2] The droop element includes a capacitor or a resistor, as described in Appendix 1, for the high-voltage pulsing power supply. [Note 3] The high-voltage pulsing power supply described in Appendix 1 has a droop inductor with an inductance of approximately 1 μH to approximately 10 mH. [Note 4] The high-voltage pulsing power supply according to Appendix 1, further comprising an energy recovery circuit electrically coupled to the droop element and the high-voltage power supply, the energy recovery circuit further comprising one or more switch modules that open and close to add charge to the droop element or to remove charge from the droop element. [Note 5] The high-voltage pulsing power supply described in Appendix 1 is coupled to a plasma chamber having plasma, and the output produces an ion energy distribution that is substantially flat over a substantial portion of the ion energy and has peaks in a narrow band of ion energy. [Note 6] The high-voltage pulsing power supply described in Appendix 4, wherein one or more switch modules of the energy recovery circuit are arranged in a full-bridge configuration or a half-bridge configuration. [Note 7] The energy recovery circuit includes a diode and an inductor arranged in series between the droop element and the high-voltage power supply, as described in Appendix 4, for the high-voltage pulsing power supply. [Note 8] The energy recovery circuit is a high-voltage pulsing power supply as described in Appendix 4, including a DC-DC converter. [Note 9] The high-voltage pulsing power supply according to Appendix 1, further comprising a plasma chamber having one or more electrodes, the one or more electrodes being electrically coupled to the output, and the plurality of pulses generating an ion energy distribution in the plasma that is substantially flat over a substantial portion of the ion energy and has peaks in a narrow band of ion energy. [Note 10] It is a plasma system, DC power supply, A switch circuit electrically coupled to the DC power supply, the switch circuit comprising a plurality of switch modules arranged in a full-bridge configuration, the switch circuit generating a plurality of pulses having a positive pulse portion, a negative pulse portion, and an amplitude greater than approximately 10kV, It is a transformer, Transformer core and The primary winding wound around the transformer core, The secondary winding wound around the transformer core, The transformer includes, A droop control circuit electrically coupled to the switch circuit and the primary winding, wherein the droop control circuit is A droop diode electrically coupled in series between the switch circuit and the primary winding, wherein the negative pulse portion of the plurality of pulses can pass from the switch circuit to the primary winding of the transformer, A droop inductor and a droop capacitor arranged in series across the droop diode, wherein the negative pulse portion of the plurality of pulses allows the pulses to pass from the switch circuit to the primary winding of the transformer, and the droop inductor and the droop capacitor store energy from the negative pulse portion of the plurality of pulses, The droop control circuit includes, An energy recovery circuit electrically coupled to the droop capacitor and the high-voltage power supply, the energy recovery circuit including one or more switch modules that open and close to add charge to the droop capacitor or to remove charge from the droop capacitor, A plasma chamber having one or more electrodes, wherein the one or more electrodes are electrically coupled to the secondary winding, and the plurality of pulses generate an ion energy distribution in the plasma that is substantially flat for a substantial portion of the ion energy and has peaks in a narrow band of ion energy; Plasma systems including... [Note 11] The aforementioned multiple pulses include a nearly flat negative pulse portion, as described in Appendix 10, for the high-voltage pulsing power supply. [Note 12] The high-voltage pulsing power supply described in Appendix 10 has a droop inductor with an inductance of approximately 1 μH to approximately 10 mH. [Note 13] The energy recovery circuit is a high-voltage pulsing power supply as described in Appendix 10, including a DC-DC converter. [Note 14] The energy recovery circuit is a high-voltage pulsing power supply as described in Appendix 10, which includes a transformer between the plurality of switch modules and the DC-DC converter. [Note 15] The high-voltage pulsing power supply according to Appendix 10, wherein the energy recovery circuit includes an energy recovery inductor and a diode arranged in series between the high-voltage power supply and one or more switch modules. [Note 16] The high-voltage pulsing power supply as described in Appendix 10, wherein one or more switch modules of the energy recovery circuit are arranged in a full-bridge configuration or a half-bridge configuration. [Note 17] A high-voltage pulsing power supply system, DC power supply, A switch circuit electrically coupled to the DC power supply, the switch circuit comprising a plurality of switch modules arranged in a full-bridge configuration, the switch circuit generating a plurality of pulses having a positive pulse portion, a negative pulse portion, and an amplitude greater than approximately 10kV, It is a transformer, Transformer core and The primary winding wound around the transformer core, The secondary winding wound around the transformer core, The transformer includes, A droop control circuit electrically coupled to the switch circuit and the primary winding, wherein the droop control circuit is A droop diode electrically coupled in series between the switch circuit and the primary winding, wherein the negative pulse portion of the plurality of pulses can pass from the switch circuit to the primary winding of the transformer, A droop inductor and a droop capacitor arranged in series across the droop diode, wherein the negative pulse portion of the plurality of pulses allows the pulses to pass from the switch circuit to the primary winding of the transformer, and the droop inductor and the droop capacitor store energy from the negative pulse portion of the plurality of pulses, The droop control circuit includes, An energy recovery circuit electrically coupled to the droop capacitor, the energy recovery circuit comprising a plurality of switch modules arranged in a half-bridge or full-bridge configuration, and a DC-DC converter, wherein the plurality of switch modules open and close to add charge to the droop capacitor or remove charge from the droop capacitor, The output is electrically coupled to the secondary winding and outputs a plurality of pulses having a substantially flat negative pulse portion, A high-voltage pulsing power supply system including this. [Note 18] The high-voltage pulsing power supply according to Appendix 17, further comprising a plasma chamber having one or more electrodes, the one or more electrodes being electrically coupled to the output, and the plurality of pulses generating an ion energy distribution in the plasma that is substantially flat over a substantial portion of the ion energy and has peaks in a narrow band of ion energy. [Note 19] The inductance of the aforementioned droop inductor is approximately 1 μH to approximately 10 mH, as described in Appendix 17 for the high-voltage pulsing power supply. [Note 20] The high-voltage pulsing power supply according to Appendix 17, wherein the energy recovery circuit includes an energy recovery inductor and a diode arranged in series between the high-voltage power supply and the DC-DC converter. [Note 21] A step of generating a first burst of high-voltage pulses and introducing it into a plasma chamber having plasma in the plasma chamber, wherein the burst of high-voltage pulses has a plurality of high-voltage pulses having a first duty cycle, and each of the plurality of high-voltage pulses has a pulse amplitude greater than 1 kV and a first pulse width, The steps include: estimating the ion energy distribution function within the plasma; The steps include comparing the estimated ion energy distribution function with the required ion energy distribution function, If the difference between the estimated ion energy distribution function and the required ion energy distribution function is greater than the threshold, Based on the difference between the estimated ion energy distribution function and the required ion energy distribution function, either or both of the second duty cycle and the second pulse width are determined. The step of generating a second burst of high-voltage pulses and introducing plasma into the plasma chamber having plasma in the plasma chamber, wherein the burst of high-voltage pulses has a plurality of high-voltage pulses having a second duty cycle, and each of the plurality of high-voltage pulses has a pulse amplitude greater than 1 kV and a second pulse width. and, A method that includes this. [Note 22] The first step is to close the first switch module of the high-voltage pulsing power supply and open the second switch module to generate a positive pulse portion of the first high-voltage pulse having an amplitude greater than approximately 1kV, At approximately the first point, the third switch module of the energy recovery circuit is closed and the fourth switch module is opened. The steps include: at a second time point, after the first time point, opening the first switch module and closing the second switch module to generate the negative pulse portion of the first high-voltage pulse; At a third time point, which is after the second time point, the third switch module is opened, At a fourth time point, after the third time point, the first switch module is closed and the second switch module is opened to generate a positive pulse portion of the second high-voltage pulse having an amplitude greater than approximately 1 kV. At approximately the fourth point described above, the step of closing the fourth switch module, At a fifth time point, which is after the fourth time point, the first switch module is opened and the second switch module is closed to generate the negative pulse portion of the second high-voltage pulse. A method that includes this.

Claims

1. A high-voltage pulsing power supply system, DC power supply and A switch circuit electrically coupled to the DC power supply, the switch circuit comprising a plurality of switch modules arranged in a full-bridge configuration, the switch circuit generating a plurality of pulses having a positive pulse portion, a negative pulse portion, and an amplitude greater than 10 kV, It is a transformer, Transformer core and The primary winding wound around the transformer core, The secondary winding wound around the transformer core, The transformer includes, A droop control circuit electrically coupled to the switch circuit and the primary winding, wherein the droop control circuit is A droop diode electrically coupled in series between the switch circuit and the primary winding, wherein the negative pulse portion of the plurality of pulses can pass from the switch circuit to the primary winding of the transformer, A droop inductor and a droop element arranged in series across the droop diode, wherein the negative pulse portion of the plurality of pulses allows the pulses to pass from the switch circuit to the primary winding of the transformer, and stores energy from the negative pulse portion of the plurality of pulses. The droop control circuit includes, An energy recovery circuit electrically coupled to the droop element and the DC power supply, the energy recovery circuit includes one or more switch modules that open and close to add charge to the droop element or to remove charge from the droop element, wherein the one or more switch modules of the energy recovery circuit are arranged in a full-bridge configuration or a half-bridge configuration, The output is electrically coupled to the secondary winding and outputs a plurality of pulses having a substantially flat negative pulse portion, A high-voltage pulsing power supply system including this.

2. The high-voltage pulsing power supply according to claim 1, wherein the droop element includes a capacitor or a resistor.

3. The high-voltage pulsing power supply according to claim 1, wherein the inductance of the droop inductor is 1 μH to 10 mH.

4. The high-voltage pulsing power supply according to claim 1, wherein the high-voltage pulsing power supply is coupled to a plasma chamber having plasma, and the output generates an ion energy distribution that is substantially flat in a portion of the ion energy and has a peak in a narrow band of ion energy.

5. The high-voltage pulsing power supply according to claim 1, wherein the energy recovery circuit includes a diode and an inductor arranged in series between the droop element and the DC power supply.

6. The high-voltage pulsing power supply according to claim 1, wherein the energy recovery circuit includes a DC-DC converter.

7. The high-voltage pulsing power supply according to claim 1, further comprising a plasma chamber having one or more electrodes, wherein the one or more electrodes are electrically coupled to the output, and the plurality of pulses generate an ion energy distribution in the plasma that is substantially flat in a portion of the ion energy and has peaks in a narrow band of ion energy.

8. It is a plasma system, DC power supply and A switch circuit electrically coupled to the DC power supply, the switch circuit comprising a plurality of switch modules arranged in a full-bridge configuration, the switch circuit generating a plurality of pulses having a positive pulse portion, a negative pulse portion, and an amplitude greater than 10 kV, It is a transformer, Transformer core and The primary winding wound around the transformer core, The secondary winding wound around the transformer core, The transformer includes, A droop control circuit electrically coupled to the switch circuit and the primary winding, wherein the droop control circuit is A droop diode electrically coupled in series between the switch circuit and the primary winding, wherein the negative pulse portion of the plurality of pulses can pass from the switch circuit to the primary winding of the transformer, A droop inductor and a droop capacitor arranged in series across the droop diode, wherein the negative pulse portion of the plurality of pulses allows the pulses to pass from the switch circuit to the primary winding of the transformer, and the droop inductor and the droop capacitor store energy from the negative pulse portion of the plurality of pulses, The droop control circuit includes, An energy recovery circuit electrically coupled to the droop capacitor and the DC power supply, the energy recovery circuit including one or more switch modules that open and close to add charge to the droop capacitor or to remove charge from the droop capacitor, A plasma chamber having one or more electrodes, wherein the one or more electrodes are electrically coupled to the secondary winding, and the plurality of pulses generate an ion energy distribution in the plasma that is substantially flat in a portion of the ion energy and has a peak in a narrow band of ion energy, the plasma chamber, Plasma systems including...

9. The high-voltage pulsing power supply according to claim 8, wherein the plurality of pulses include a substantially flat negative pulse portion.

10. The high-voltage pulsing power supply according to claim 8, wherein the inductance of the droop inductor is 1 μH to 10 mH.

11. The high-voltage pulsing power supply according to claim 8, wherein the energy recovery circuit includes a DC-DC converter.

12. The high-voltage pulsing power supply according to claim 11, wherein the energy recovery circuit includes a transformer between the plurality of switch modules and the DC-DC converter.

13. The high-voltage pulsing power supply according to claim 8, wherein the energy recovery circuit includes an energy recovery inductor and a diode arranged in series between the DC power supply and one or more switch modules.

14. The high-voltage pulsing power supply according to claim 8, wherein one or more switch modules of the energy recovery circuit are arranged in a full-bridge configuration or a half-bridge configuration.

15. A high-voltage pulsing power supply system, DC power supply and A switch circuit electrically coupled to the DC power supply, the switch circuit comprising a plurality of switch modules arranged in a full-bridge configuration, the switch circuit generating a plurality of pulses having a positive pulse portion, a negative pulse portion, and an amplitude greater than 10 kV, It is a transformer, Transformer core and The primary winding wound around the transformer core, The secondary winding wound around the transformer core, The transformer includes, A droop control circuit electrically coupled to the switch circuit and the primary winding, wherein the droop control circuit is A droop diode electrically coupled in series between the switch circuit and the primary winding, wherein the negative pulse portion of the plurality of pulses can pass from the switch circuit to the primary winding of the transformer, A droop inductor and a droop capacitor arranged in series across the droop diode, wherein the negative pulse portion of the plurality of pulses allows the pulses to pass from the switch circuit to the primary winding of the transformer, and the droop inductor and the droop capacitor store energy from the negative pulse portion of the plurality of pulses, The droop control circuit includes, An energy recovery circuit electrically coupled to the droop capacitor, the energy recovery circuit comprising a plurality of switch modules arranged in a half-bridge or full-bridge configuration, and a DC-DC converter, wherein the plurality of switch modules open and close to add charge to the droop capacitor or remove charge from the droop capacitor, The output is electrically coupled to the secondary winding and outputs a plurality of pulses having a substantially flat negative pulse portion, A high-voltage pulsing power supply system including this.

16. The high-voltage pulsing power supply according to claim 15, further comprising a plasma chamber having one or more electrodes, the one or more electrodes being electrically coupled to the output, and the plurality of pulses generating an ion energy distribution in the plasma that is substantially flat in a portion of the ion energy and has peaks in a narrow band of ion energy.

17. The high-voltage pulsing power supply according to claim 15, wherein the inductance of the droop inductor is 1 μH to 10 mH.

18. The high-voltage pulsing power supply according to claim 15, wherein the energy recovery circuit includes an energy recovery inductor and a diode arranged in series between the DC power supply and the DC-DC converter.

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