Scanning impedance measurements in radio frequency plasma processing chambers.

Abstract

An embodiment includes a method for processing a substrate in a plasma processing system, the method including: supplying an RF signal to an electrode assembly through an RF match by an RF generator while an RF match is set to a first match point; and supplying a voltage waveform to the electrode assembly by a waveform generator while the RF signal is supplied to the electrode assembly. The method also includes receiving a synchronization signal from the RF generator or the waveform generator by the RF match; measuring different sets of impedance-related data of the plasma processing system over different time periods and after different delays by an output sensor of the RF match; calculating a composite impedance parameter by the RF match based on the different sets of impedance-related data; and adjusting a match parameter in the RF match based on the composite impedance parameter to achieve a second match point.

Description

[Technical Field]

[0001]

[0001] Embodiments of the present invention generally relate to systems and methods used in semiconductor device manufacturing. More specifically, embodiments provided herein generally include systems and methods for processing substrates in a plasma processing system. [Background technology]

[0002]

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

[0003] A typical reactive ion etching (RIE) plasma processing chamber includes a radio frequency (RF) bias generator that supplies an RF voltage to a powered electrode. In a capacitively coupled gas discharge, the plasma is generated using a radio frequency (RF) generator coupled to a powered electrode located within an electrostatic chuck (ESC) assembly or another part of the processing chamber. Typically, an RF matching network ("RF match") conditions the RF waveform provided by the RF generator and delivers RF power to an apparent 50 Ω load, minimizing reflected power and maximizing power delivery efficiency. If the load impedance is not properly matched to the impedance of the source (e.g., the RF generator), a portion of the forward-directed RF waveform may be reflected back along the same transmission line in the opposite direction.

[0004] Many plasma processes also utilize DC voltage pulsing to control the plasma sheath disposed above the substrate being processed. During processing, the DC voltage pulsing causes the generated plasma sheath to toggle between a state with a thick plasma sheath and a state without a plasma sheath. Typical DC pulsing techniques are configured to supply voltage pulses at frequencies exceeding 100 kHz (e.g., frequencies exceeding 400 kHz). The toggling of the plasma sheath by the supplied DC pulse voltage waveform causes the impedance value of the plasma load to change over time. It has been discovered that the interaction between the RF waveform and the DC pulse voltage waveform simultaneously supplied during plasma processing can result in different plasma processing results, primarily due to the inability of the RF matching portion of the RF power supply system to adjust the RF match point to account for the rapidly changing plasma load impedance value over time. Conventional impedance matching components and matching processes cannot accommodate the rapid changes in the magnitude of the plasma load impedance, resulting in undesirable match points being detected during matching. As a result, the amount of RF power actually delivered to the plasma load typically fluctuates due to two factors: These are: 1) intermodulation distortion (IMD) of the RF signal and 2) undesirably high reflected RF power found at harmonics of the driving RF frequency. Intermodulation distortion caused by the interaction between the RF waveform and the DC pulsed voltage waveform causes, at a minimum, the amplitude of the RF signal to change over time. Interaction or intermodulation between the RF waveform and the DC pulsed voltage waveform results in the formation of additional undesirable waveform components at frequencies other than just the harmonic frequencies (i.e., integer multiples) of the interacting signals, such as either the RF waveform or the DC pulsed waveform. The creation of IMD components in the power delivery system reduces the actual forward RF power delivered to the plasma load.Due to, at least, unavoidable variations in processing chamber power supply configurations and variations in power supply components, rapidly changing plasma load impedance values ​​result in undesirable variations in plasma processing results within a single plasma processing chamber, among similarly configured processing chambers on a single processing system, and even among similarly configured plasma processing chambers in different plasma processing systems within a semiconductor manufacturing site. Furthermore, the resulting IMD components are also not easily accounted for in most power supply systems due to the wide range of frequencies that can occur during plasma processing in the same or different processing chambers, thus causing unpredictable variations in the power actually delivered to the plasma load during plasma processing.

[0005]

[0005] Therefore, there is a need in the art for a plasma processing apparatus and biasing method that can solve at least the problems outlined above. Summary of the Invention

[0006] An embodiment of the present disclosure includes a method for processing a substrate in a plasma processing system, the method including: supplying an RF signal by an RF generator through an RF match to an electrode assembly disposed within the plasma processing system, wherein the RF match is set to a first match point while supplying the RF signal; and supplying a voltage waveform by a waveform generator to the electrode assembly disposed within the plasma processing system while the RF signal is supplied to the electrode assembly. The method further includes receiving, by an RF match, a synchronization signal from an RF generator or a waveform generator; measuring, by an output sensor of the RF match, a first set of impedance-related data of the plasma processing system over a first period of time, the first period starting after a first delay triggered by a first portion of a first waveform pulse of the synchronization signal; measuring, by an output sensor of the RF match, a second set of impedance-related data of the plasma processing system over a second period of time, the second period starting after a second delay triggered by the first portion of the first waveform pulse of the synchronization signal; calculating, by the RF match, a composite impedance parameter based on the measured first set of impedance-related data and the second set of measured impedance-related data; and adjusting a match parameter in the RF match based on the calculated composite impedance parameter to achieve a second match point.

[0007]

[0007] Embodiments of the present application may further provide a method for processing a substrate in a plasma processing system, comprising generating a plasma in a processing space of the plasma processing system, wherein generating the plasma by supplying an RF waveform comprises sequentially supplying a first RF pulse and a second RF pulse, the first RF pulse comprising a first RF power level and the second RF pulse comprising a second RF power level, the sequentially supplied first RF pulse and second RF pulse being formed by supplying an RF signal to an electrode assembly of the plasma processing system through RF matching. The method may further comprise detecting a transition region between the first RF pulse and the second RF pulse, determining a scanned impedance of the plasma processing system during the transition region between the first RF pulse and the second RF pulse, determining a baseline impedance of the plasma processing system between the first RF pulse or the second RF pulse, and calculating a composite impedance parameter based on the scanned impedance and the baseline impedance.

[0008]

[0008] Embodiments of the present application may further provide a plasma processing system comprising: an RF generator configured to supply an RF signal to an electrode assembly disposed within the plasma processing system through an RF match, wherein the RF match is set to a first match point while the RF signal is being supplied to the electrode assembly; and a voltage waveform generator configured to supply a voltage waveform to the electrode assembly disposed within the plasma processing system while the RF signal is being supplied to the electrode assembly. The RF match comprises an input sensor, an output sensor, an RF match controller, and a memory for storing a program executed within the RF match controller. The program includes instructions that, when executed, cause an RF matching controller to receive, via the RF matching, a synchronization signal from an RF generator or a waveform generator; measure, using an output sensor, a first set of impedance-related data of the plasma processing system over a first period of time, the first period starting after a first delay triggered by a first portion of a first waveform pulse of the synchronization signal; measure, using an output sensor of the RF matching, a second set of impedance-related data of the plasma processing system over a second period of time, the second period starting after a second delay triggered by the first portion of the first waveform pulse of the synchronization signal; calculate, by the RF matching controller, a composite impedance parameter based on the measured first set of impedance-related data and the measured second set of impedance-related data; and adjust a match parameter in the RF matching controller based on the calculated composite impedance parameter to achieve a second match point.

[0009]

[0009] So that the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure briefly summarized above can be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only exemplary embodiments and therefore should not be considered as limiting the scope of the present disclosure, which may also admit of other equally effective embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a simplified schematic diagram of a plasma processing system according to one or more embodiments. [Figure 2]

[0011] 1 is a schematic cross-sectional view of a plasma processing system that can be configured to perform one or more of the plasma processing methods described herein, according to one or more embodiments. [Figure 3A]

[0012] 1A-1D are schematic diagrams of a radio frequency (RF) power supply system, according to one or more embodiments. [Figure 3B]

[0013] 1 illustrates an example of a tuning circuit that may be used in a radio frequency (RF) power supply system, according to one or more embodiments. [Figure 3C] 1 illustrates an example of a tuning circuit that may be used in a radio frequency (RF) power supply system, according to one or more embodiments. [Figure 4]

[0014] 1 illustrates a voltage pulse provided in a voltage waveform established at a substrate by providing a voltage pulse to a bias electrode during plasma processing, according to one or more embodiments. [Figure 5A]

[0015] 1 illustrates a voltage waveform supplied to a bias electrode and a voltage pulse supplied within a synchronization signal supplied to an RF match during plasma processing according to one or more embodiments. [Figure 5B]1 illustrates a voltage waveform supplied to a bias electrode and a voltage pulse supplied within a synchronization signal supplied to an RF match during plasma processing according to one or more embodiments. [Figure 5C] 1 illustrates a voltage waveform supplied to a bias electrode and a voltage pulse supplied within a synchronization signal supplied to an RF match during plasma processing according to one or more embodiments. [Figure 5D] 1 illustrates a voltage waveform supplied to a bias electrode and a voltage pulse supplied within a synchronization signal supplied to an RF match during plasma processing according to one or more embodiments. [Figure 6]

[0016] 1 illustrates multiple synchronization signals provided during plasma processing according to one or more embodiments. [Figure 7A]

[0017] 1 illustrates multiple RF pulses delivered to an electrode during plasma processing according to one or more embodiments. [Figure 7B]

[0018] 1 shows example measurements of resistance (R) and reactance (X) resulting from the application of RF pulses to a composite load as a function of time during plasma processing, according to one or more embodiments. [Figure 8A]

[0019] 1 illustrates a method of using an RF plasma processing system, according to certain embodiments. [Figure 8B] 1 illustrates a method of using an RF plasma processing system, according to certain embodiments. [Figure 8C] 1 illustrates a method of using an RF plasma processing system, according to certain embodiments. [Figure 9]

[0020] 1 illustrates a method of using an RF plasma processing system when multiple RF pulses are supplied to an electrode of the plasma processing system, according to certain embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0021] For ease of understanding, wherever possible, like reference numerals have been used to designate like elements common to the figures. It is contemplated that components and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0012]

[0022] FIELD OF THE DISCLOSURE Embodiments of the present disclosure generally relate to systems used in semiconductor device manufacturing processes. More specifically, embodiments provided herein generally include apparatus and methods for synchronizing and controlling the supply of RF bias voltage to one or more electrodes disposed within a plasma processing chamber to better control the efficient delivery of RF power to a plasma formed in a processing region of the plasma processing chamber.

[0013]

[0023] FIG. 1 is a schematic diagram of a processing system configured to perform one or more of the methods set forth herein, according to one or more embodiments. In some embodiments, the plasma processing system 10 is configured for a plasma-assisted etch process, such as a reactive ion etch (RIE) plasma process. The plasma processing system 10 can also be used for other plasma-assisted processes, such as a plasma-enhanced deposition process (e.g., a plasma-enhanced chemical vapor deposition (PECVD) process, a plasma-enhanced physical vapor deposition (PEPVD) process, a plasma-enhanced atomic layer deposition (PEALD) process, a plasma treatment process, a plasma-based ion implantation process, or a plasma doping (PLAD) process. In one configuration, as shown in FIG. 1, the plasma processing system 10 is configured to form a capacitively coupled plasma (CPP). However, in some embodiments, the plasma can alternatively be generated by an inductively coupled source disposed above a processing region of the plasma processing chamber system 10.

[0014]

[0024] The plasma processing system 10 includes a process chamber 100, a chamber lid 123, a system controller 126, a substrate support assembly 136, a gas delivery system 182, a high voltage supply 173, a pulsed voltage (PV) waveform generator 175, a radio frequency (RF) generator 171, and an RF match 172. In some embodiments, the RF generator 171 and the PV waveform generator 175 are both coupled to the substrate support assembly 136. The RF generator 171 is configured to provide an RF signal to ignite and sustain a plasma 101 in the process space 129 of the process chamber 100. The PV waveform generator 175 is configured to provide a pulsed voltage (PV) waveform to bias the substrate support assembly 136.

[0015]

[0025] A system controller 126 is communicatively coupled to both the RF generator 171 and the PV waveform generator 175. The system controller 126 is used to control the process sequence used to process substrates. The system controller 126 is coupled to the RF generator 171 using a first communication line 181 and to the PV waveform generator 175 using a second communication line 187. The system controller 126 is configured to send command signals to the RF generator 171 and the PV waveform generator 175 via their respective communication lines 181, 187. The communication lines 181, 187 are also used to transfer data and synchronize the delivery of the RF and PV waveform signals from the RF generator 171 and the PV waveform generator 175, respectively, to desired electrodes within the processing chamber.

[0016]

[0026] The RF generator 171 is coupled to an electrode in the substrate support assembly 136 via an RF match 172 disposed between the RF match 172 and the substrate support assembly 136. The RF match 172 includes an input sensor 116 and an output sensor 117. The input sensor is configured to measure impedance-related parameters and other characteristics of the RF generator 171 (i.e., the source), such as voltage, current, harmonics, phase, power, and combinations thereof. The output sensor 117 is configured to measure impedance-related data, such as voltage, current, harmonics, phase, power, impedance, and combinations thereof, of the plasma processing system 10 (e.g., the plasma 101 generated in the process space 129, known as the load). If the load impedance and the source impedance are not properly matched, portions of the RF waveform may be reflected back. Therefore, the RF match 172 is configured to adjust one or more electrical components in the RF match 172 based on the impedance measured by the input sensor 116 and the output sensor 117 during processing. This will be described in more detail below.

[0017]

[0027] However, as described further below, in plasma processing configurations in which a PV waveform and an RF signal are simultaneously supplied to one or more electrodes disposed within the processing region 129 to form a plasma 101 therein, the impedance of the composite load created by the plasma 101 will vary due, at least in part, to variations in the RF power level and / or variations in the voltage applied to each of the voltage pulses included in the PV waveform supplied from the PV waveform generator 175. In some other plasma processing configurations in which a pulsed RF signal is supplied to the processing region 129 of the plasma processing chamber 100 to form a plasma 101 therein, the impedance of the composite load created by the plasma 101 will vary due, at least in part, to variations in the RF power level. As the impedance of the composite load changes, the RF matching element used to ensure efficient delivery of RF power to the composite load must adjust its impedance accordingly to ensure that maximum forward RF power is delivered to the composite load while always minimizing the amount of reflected power. However, most conventional RF matches contain mechanical tuning elements that cannot keep up with the rate at which the complex load is changing impedance, resulting in large variations in the match point, the amount of reflected RF power, and inefficiencies and / or damage to the power delivery system.

[0018]

[0028] In some embodiments, the PV waveform generator 175 is coupled to an electrode disposed within the substrate support assembly 136 via a filter 109 disposed between the PV waveform generator 175 and the substrate support assembly 136. The filter 109 is configured to isolate the PV waveform generator 175 from RF and other signals generated within the processing chamber 100 during plasma processing.

[0019]

[0029] To control and synchronize the delivery of the RF signal from the RF generator 171 through the RF match 172 to the electrodes in the processing chamber 100, the RF generator 171 is also separately coupled to the RF match 172 using a third communication line 188. The third communication line 188 enables bidirectional communication between the RF match 172 and the RF generator 171 and is configured to control the RF signal and efficiently deliver it to the composite load. To control and synchronize the delivery of the PV waveform from the PV waveform generator 175 to the electrodes in the processing chamber 100, the PV waveform generator 175 is also coupled to the RF match 172 using a fourth communication line 190. The fourth communication line 190 is also configured to enable bidirectional communication between the RF match 172 and the PV waveform generator 175 and to help control and synchronize the delivery of the PV waveform and the RF signal to the composite load. In some embodiments, the RF generator 171 is configured to send a synchronization signal to the RF match 172 via the third communication line 188. In some embodiments, the PV waveform generator 175 is configured to transmit a synchronization signal to the RF match 172 via a fourth communication line 190. In some embodiments, the synchronization signal transmitted from the RF generator 171 or the synchronization signal transmitted from the PV waveform generator 175 is used to trigger the output sensor 117 to impedance-related data of the plasma processing system 10. This will be described in more detail below. In some embodiments, the synchronization signals transmitted from the RF generator 171 and the PV waveform generator 175 are also received by the RF match 172 and transmitted from the RF match 172 to the PV waveform generator 175 and the RF generator 171, respectively, enabling synchronization of the RF match 172, the PV waveform generator 175, and the RF generator 171.

[0020]

[0030] In some embodiments, the high voltage supply 173 is also coupled to an electrode disposed within the substrate support assembly 136. The high voltage supply 173 is configured to supply a chucking voltage to the substrate support assembly 136. The high voltage supply 173 is coupled to the substrate support assembly 136 via a filter 109. The filter is disposed between the high voltage supply 173 and the substrate support assembly 136.

[0021]

[0031] A gas supply system 182 is coupled to the processing space 129 of the processing chamber 100. The gas supply system 182 is configured to supply at least one processing gas from at least one gas processing source 119 to the processing space 129 via one or more gas inlets 128 positioned through the chamber lid 123.

[0022]

[0032] 2 is a more detailed schematic cross-sectional view of the configuration of the plasma processing system 10 shown in FIG. 1 configured to perform one or more of the plasma processing methods set forth herein. In one configuration, as shown in FIG. 2, the plasma processing system 10 is configured to form a capacitively coupled plasma (CPP). However, in some embodiments, the plasma 101 may alternatively be generated using an inductively coupled source positioned above the processing region 129 of the plasma processing system 10. In this configuration, a coil may be mounted on top of the ceramic lid (vacuum boundary) of the processing chamber 100.

[0023]

[0033] The plasma processing system 10 includes a processing chamber 100, a substrate support assembly 136, a gas supply system 182, a power system 183, an RF power system 189, and a system controller 126. As shown in FIG. 2 , the processing chamber 100 includes a chamber body 113 including a chamber lid 123, one or more sidewalls 122, and a chamber base 124. The chamber lid 123, the one or more sidewalls 122, and the chamber base 124 collectively define a processing space 129. The one or more sidewalls 122 and the chamber base 124 generally comprise a material (such as aluminum, an aluminum alloy, or a stainless steel alloy) sized and shaped to provide structural support for the elements of the processing chamber 100 and configured to withstand pressure and additional energy applied thereto while a plasma 101 is generated in a vacuum environment maintained within the processing space 129 of the processing chamber 100 during processing. The substrate 103 is loaded into and removed from the processing space 129 through an opening (not shown) in one of the sidewalls 122. The opening is sealed with a slit valve (not shown) during plasma processing of the substrate 103. A gas supply system 182 coupled to the processing space 129 of the processing chamber 100 includes a process gas source 119 and a gas inlet 128 disposed through the chamber lid 123. The gas inlet 128 is configured to supply one or more process gases from the multiple process gas sources 119 to the processing space 129.

[0024]

[0034] As described above, the processing chamber 100 further includes an upper electrode (e.g., the chamber lid 123) and a substrate support assembly 136 disposed within the processing space 129. As shown in FIG. 2 , in one embodiment, a radio frequency (RF) source is electrically coupled to a lower electrode (e.g., the substrate support base 107) disposed within the substrate support assembly 136. The RF generator 171 is configured to provide an RF signal to ignite and maintain the plasma 101 between the upper and lower electrodes. In some alternative configurations, the RF generator 171 may also be electrically coupled to the upper electrode, such as the chamber lid 123.

[0025]

[0035] As shown in FIG. 2 , the substrate support assembly 136 includes a substrate support 105, a substrate support base 107, an insulator plate 111, a ground plate 112, a plurality of lift pins 186, one or more substrate potential sensing assemblies 184, and a bias electrode 104. Each lift pin 186 is disposed through a through-hole formed in the substrate support assembly 136 and is used to facilitate the transfer of the substrate 103 to and from the substrate receiving surface 105A of the substrate support 105. The substrate support 105, which may include an electrostatic chuck, is formed of a dielectric material. The dielectric material may include a bulk-sintered ceramic material, a corrosion-resistant metal oxide (e.g., aluminum oxide (AlO), titanium oxide (TiO), yttrium oxide (YO)), a metal nitride material (e.g., aluminum nitride (AlN), titanium nitride (TiN)), a mixture thereof, or a combination thereof.

[0026]

[0036] The substrate support base 107 is formed of an electrically conductive material (e.g., aluminum, an aluminum alloy, or a stainless steel alloy). The substrate support base 107 is electrically insulated from the chamber base 124 by an insulating plate 111 and a grounded plate 112 disposed between the insulating plate 111 and the chamber base 124. In some embodiments, the substrate support base 107 is configured to regulate the temperature of both the substrate support 105 and a substrate 103 disposed on the substrate support 105 during substrate processing. In some embodiments, the substrate support base 107 includes one or more cooling channels (not shown) therein, which are in fluid communication with and fluidly coupled to a cooling source (not shown), such as a refrigerant source or a substrate source, having a relatively high electrical resistance. In other embodiments, the substrate support 105 includes a heater (not shown) for heating the substrate support 105 and a substrate 103 disposed on the substrate support 105.

[0027]

[0037] The bias electrode 104 is embedded in the dielectric material of the substrate support 105. Typically, the bias electrode 104 is formed from one or more conductive components. The conductive components typically include a mesh, a foil, a plate, or a combination thereof. In some embodiments, the bias electrode 104 may function as a chuck pole (i.e., an electrostatic chuck electrode) used to secure (e.g., electrostatically chuck) the substrate 103 to the substrate receiving surface 105A of the substrate support 105. Generally, a parallel plate-like structure is formed by the bias electrode 104 and a layer of dielectric material disposed between the bias electrode 104 and the substrate receiving surface 105A. The dielectric material typically has an effective capacitance C between about 5 nF and about 50 nF. E Typically, the layer of dielectric material (e.g., aluminum nitride (AlN), aluminum oxide (Al2O3), etc.) has a thickness between about 0.03 mm and about 5 mm, such as between about 0.1 mm and about 3 mm, such as between about 0.1 mm and about 1 mm, or even between about 0.1 mm and about 0.5 mm. The bias electrode 104 is electrically coupled to a clamping network that supplies a chucking voltage thereto. The clamping network includes a high-voltage DC supply 173 that is coupled to a filter 178A of a filter assembly 178 that is disposed between the high-voltage supply 173 and the bias electrode 104. In one embodiment, the filter 178A is a low-pass filter configured to block RF frequencies and pulsed voltage (PV) waveform signals supplied by other bias components found in the processing chamber 100 from reaching the high-voltage supply 173 during plasma processing. In one configuration, the static DC voltage is between about −5000 V and about 5000 V and is supplied using an electrical conductor (such as a coaxial power supply line 106). In some embodiments, the bias electrode 104 may also bias the substrate 103 relative to the plasma 101 using one or more of the pulsed voltage biasing methods described in more detail below using a PV waveform generator 175.

[0028]

[0038] In some configurations, the substrate support assembly 136 further includes an edge control electrode 115. The edge control electrode 115 is formed from one or more conductive components. The conductive components typically include a mesh, a foil, a plate, or a combination thereof. The edge control electrode 115 is positioned below the edge ring 114, surrounds the bias electrode 104, and / or is spaced apart from the center of the bias electrode 104. Generally, for a processing chamber 100 configured to process a circular substrate, the edge control electrode 115 is annular in shape, made from a conductive material, and configured to surround at least a portion of the bias electrode 104. As seen in FIG. 2 , the edge control electrode 115 is positioned within the region of the substrate support 105 and is biased using an output from a pulse voltage (PV) waveform generator 175. In some configurations, the edge control electrode 115 is biased using a PV waveform generator that is different from the PV waveform generator 175 used for the bias electrode 104. In another configuration, the edge control electrode 115 is biased by splitting off a portion of the signal provided from the PV waveform generator 175 to the bias electrode 104 .

[0029]

[0039] 2, the power system 183 includes a high-voltage power supply 173, a PV waveform generator 175, and a current source 177. The RF power system 189 includes a radio frequency (RF) generator 171, an RF match 172, and an RF filter 174. In one example, as shown in FIG. 2, a power supply line 163 electrically connects the output of the RF generator 171 to the RF match 172, the RF filter 174, and the substrate support base 107. As described above, during plasma processing, the high-voltage power supply 173 provides a constant chucking voltage, while the RF generator 171 provides an RF signal to the processing region and the PV waveform generator 175 establishes a PV waveform at the bias electrode 104. A sufficient amount of RF power is applied to the RF bias voltage signal, also referred to herein as an RF waveform, to supply an electrode (e.g., the substrate support base 107) to form a plasma 101 within the processing space 129 of the processing chamber 100. In one configuration, the RF waveform has a frequency range between about 1 MHz and about 200 MHz, for example, between 2 MHz and 40 MHz.

[0030]

[0040] In some embodiments, power system 183 further includes a filter assembly 178 for electrically isolating one or more of the components included within power system 183. Power supply line 160 electrically connects the output of high-voltage DC supply 173 to filter assembly 178. Power supply line 161 electrically connects the output of PV waveform generator 175 to filter assembly 178. Power supply line 162 connects the output of current source 177 to filter assembly 178. In some embodiments, current source 177 is selectively coupled to bias electrode 104 using a switch (not shown) disposed in power supply line 162 to enable current source 177 to supply a desired current to bias electrode 104 during one or more phases (e.g., ionic current phases) of the voltage waveform generated by PV waveform generator 175. As seen in FIG. 2 , filter assembly 178 includes multiple separate filter components (i.e., individual filters 178A-178C), each electrically coupled to an output node via power supply line 164. In an alternative configuration, filter assembly 178 includes one common filter electrically coupled to the output node via power supply line 164. Power supply lines 160-164 include electrical conductors including combinations of coaxial cables, such as flexible coaxial cables connected in series with rigid coaxial cables, insulated high voltage corona resistant hook-up wires, bare wires, metal rods, electrical connectors, or any combination thereof.

[0031]

[0041] The system controller 126, also referred to herein as a processing chamber controller, includes a central processing unit (CPU) 133, memory 134, and support circuits 135. The system controller 126 is used to control the process sequence used to process the substrate 103. The CPU is a general-purpose computer processor configured for use in an industrial environment to control the processing chamber and its associated sub-processors. The memory 134, described herein as generally non-volatile memory, may include random access memory, read-only memory, a hard disk drive, or other suitable forms of local or remote digital storage. The support circuits 135 are conventionally coupled to the CPU 133 and include cache, clock circuits, input / output subsystems, power supplies, etc., and combinations thereof. Software instructions (programs) and data may be coded and stored in the memory 134 to instruct the processor in the CPU 133. Software programs (or computer instructions) readable by the CPU 133 in the system controller 126 determine which tasks are executable by components in the plasma processing chamber 10.

[0032]

[0042] Typically, a program readable by the CPU 133 in the system controller 126 includes code that, when executed by the CPU 133, performs tasks related to the plasma processing schemes described herein. The program may include instructions that are used to control various hardware and electrical components within the plasma processing chamber 10 to perform various process tasks and sequences used to implement the methods described herein. In one embodiment, the program includes instructions used to perform one or more of the steps described below in connection with FIGS. 5-9.

[0033]

[0043] 3A is a schematic diagram of an RF power supply system according to one or more embodiments. FIG. 3A includes a schematic diagram of an RF match 172 and an RF generator 171 configured to perform the methods described herein. The RF match 172 includes an RF match controller 302, an input sensor 116, an output sensor 117, a first RF filter 308, a second RF filter 310, a tuning circuit 312, an interlock 314, and a memory 316. The first RF filter 308 and the second RF filter 310 can be configured to block frequencies from other signals transmitted to the processing chamber 100 to avoid interference. For example, the first RF filter 308 and the second RF filter can be low-pass filters, high-pass filters, or band-pass filters.

[0034]

[0044] The RF matching controller 302 is configured to receive an RF waveform from the RF generator 171, adjust the RF waveform to minimize reflected power and maximize power delivery efficiency, and deliver the adjusted RF waveform to the processing chamber 100. In some embodiments, the PV waveform generator 175 is configured to deliver a PV waveform to the processing chamber 100 simultaneously, as described above. The RF generator 171 and the PV waveform generator 175 are both coupled to and synchronized with the system controller 126. The RF matching controller 302 may be communicatively coupled to an interlock 314, a memory 316, a tuning circuit 312, an input sensor 116, and an output sensor 117. In some embodiments, the RF matching controller 302 is also in communication with an electronic device including a display and a user interface, such as a conventional computer (e.g., a user PC), which may in some cases form part of the system controller 126. The RF matching controller 302 includes a central processing unit (CPU). The RF matching controller 302 is configured to control the tuning circuit 312 to change the impedance parameters of the RF matching controller 172. The tuning circuit 312 described herein may be a T-network tuning circuit, a π (pi) network tuning circuit, an L-network circuit, etc. The tuning circuit 312 may include at least one electrical component, such as a variable capacitor and / or inductor, that can be adjusted by the RF matching controller 302 to change the impedance of the RF waveform supplied to the processing chamber 100. FIGS. 3B and 3C show examples of an L-network tuning circuit and a π-network tuning circuit that include variable capacitors C1 and C2, and C1, C2, and C3, respectively, that can be used to adjust the impedance of the tuning circuit 312 to a complex load and, therefore, the match point of the RF match 172. The tuning circuit 312 has an input 312A that is directly or indirectly coupled to the input sensor 116 and an output 312B that is directly or indirectly coupled to the output sensor 117.

[0035]

[0045] The memory 316 may be programmed for long-term or short-term memory storage. Generally non-volatile memory, the memory 316 described herein may include random access memory, read-only memory, a hard disk drive, or other suitable forms of local or remote digital storage. Software instructions (programs) and data may be coded and stored in the memory 316 to instruct a processor within the RF matching controller 302. The software programs (or computer instructions) readable by the RF matching controller 302 determine which tasks can be performed by components within the plasma processing system 10. Typically, the programs readable by the RF matching controller 302 include code that, when executed, performs tasks related to the plasma processing schemes described herein. The programs may include instructions used to control the RF matching 172 using the methods described herein. In one embodiment, the programs include instructions used to perform one or more of the steps described below in connection with FIGS. 5A-9.

[0036]

[0046] The output sensor 117 may include a voltage sensor and / or a current sensor configured to measure the impedance or characteristics of the complex load formed within the plasma processing system 10 during processing, as described above. In other words, the output sensor 117 is configured to measure impedance-related data of the complex load, such as current, voltage, phase, harmonics, power, and combinations thereof, and report them to the RF matching controller 302. The RF matching controller 302 may then determine the impedance based on the impedance-related data collected by the output sensor 117. The output sensor 117 may be located inside or outside the housing of the RF matching 172, and in some embodiments, may be located elsewhere within the processing chamber 100.

[0037]

[0047] The input sensors 116 may include voltage sensors and / or current sensors configured to measure impedance-related data based on the RF waveform provided by the RF generator 171, such as current, phase, voltage, harmonics, power, and combinations thereof, and report them to the RF matching controller 302. The RF matching controller 302 may then determine the impedance based on the impedance-related data collected by the input sensors 116.

[0038]

[0048] In an embodiment, input sensor 116 and output sensor 117 are each configured to measure impedance-related data based on one or more synchronization signals received from RF generator 171 and / or PV waveform generator 175. There are multiple possible paths for the synchronization signals to reach the sensors. For example, an RF synchronization signal may be transmitted from RF generator 171 to input sensor 116, output sensor 117, and PV waveform generator 175. RF generator 171 may send the synchronization signal to PV waveform generator 175, which may then forward the synchronization signal to input sensor 116 and output sensor 117.

[0039]

[0049] While processing a sample, the first set of impedance-related data during a data interval may be triggered by a PVT synchronization signal, an RF synchronization signal, an external synchronization signal from a signal generator, or an internal synchronization signal with detected pulse edges, as further described below. In one example, a PV synchronization signal may be sent from PV waveform generator 175 to input sensor 116, output sensor 117, and RF generator 171. In another example, PV waveform generator 175 may send a synchronization signal to RF generator 171, which may forward the synchronization signal to input sensor 116 and output sensor 117.

[0040]

[0050] FIG. 4 illustrates example voltage pulses provided within a voltage waveform established at a substrate by supplying voltage pulses to a bias electrode during plasma processing using a PV waveform generator 175, according to one or more embodiments. It has been discovered that establishing a PV waveform at a substrate during plasma processing can be advantageously used to control aspects of the plasma sheath formed over the substrate surface during plasma processing. Controlling the size and shape of the plasma sheath formed over the substrate surface allows for control of ion interactions with the substrate surface during processing, including control of the ion energy distribution function (IEDF), ion directionality, and other plasma-related properties. FIG. 4 illustrates two example voltage waveforms that may be established at a substrate 103 disposed on the substrate receiving surface 105A of a substrate support assembly 136 of a processing chamber by supplying a pulsed voltage waveform to a bias electrode 104 of the processing chamber. Waveform 225 is an example of an uncompensated pulsed voltage (PV) waveform established at a substrate 103 during plasma processing by supplying a PV waveform to the bias electrode 104. Waveform 230 is an example of a compensating pulsed voltage (PV) waveform established at the substrate 103 by applying a negative ramp waveform to the bias electrode 104 of the processing chamber during the "ion current phase" portion of the PV waveform cycle using the current source 177. The compensating pulsed voltage (PV) waveform can alternatively be established by applying a negative voltage ramp during the ion current phase of the pulsed voltage waveform generated by the PV waveform generator 175.

[0041]

[0051] 4, waveforms 225 and 230 include two main phases (i.e., an ion current phase and a sheath collapse phase). Both portions of waveforms 225 and 230 (the ion current phase and the sheath collapse phase) can be established alternately and / or separately at substrate 103 during plasma processing. At the beginning of the ion current phase, the negative portion (e.g., the ion current portion) of the PV waveform supplied by PV waveform generator 175 to bias electrode 104 causes a voltage drop at substrate 103, forming a high-voltage sheath above substrate 103. The high-voltage sheath can accelerate positive ions generated in the plasma during the ion current phase toward the biased substrate, thereby controlling the amount and characteristics of the etching process occurring at the substrate surface during plasma processing, in the case of an RIE process. In some embodiments, the ion current phase desirably includes a region of the pulsed voltage waveform that achieves a voltage at the substrate that is generally stable or minimally changing throughout the phase. It should be noted that significant variations in the voltage established at the substrate during the ion current phase, as indicated by the positive slope of waveform 225, result in undesirable variations in the ion energy distribution function (IEDF) and, therefore, undesirable characteristics of the etched features formed in the substrate during the RIE process.

[0042]

[0052] The plasma sheath impedance varies in response to the applied PV waveform voltage applied in the PV waveform pulses provided by the PV waveform generator 175. When a PV waveform and an RF signal are simultaneously provided to the electrodes to form the plasma 101, the impedance of the load created by the plasma 101 varies in response to changes in the voltage applied with each voltage pulse of the PV waveform and interacts with the RF signal provided by the RF generator 171. Similarly, the impedance of the load created by the plasma 101 may also vary as the power level of the RF signal changes or when a pulsed RF signal is used to form the plasma 101. Conventional RF matching is unable to determine such impedance changes and adjust the match point in real time.

[0043]

[0053] 5A-5D and 8A-8C illustrate a method for using RF match 172 to sample the change in impedance of the complex load generated by plasma 101 and update the match point based on a predetermined point in the varying voltage applied to each of the voltage pulses provided in the PV waveform. Each of FIGS. 5A-5D illustrates a voltage pulse and synchronization signal (FIG. 5B) used in conjunction with the method described in FIGS. 8A-8C to improve control of RF power delivered during plasma processing, according to one or more embodiments. FIGS. 5A-5D illustrate a process by which RF match 172 gathers information useful for updating the match point during a portion of one or more pulses in the PV waveform. The match point can be updated based on sampled impedance measured at a point in plasma processing system 10 during a portion of one or more pulses in the PV waveform. FIG. 6 illustrates multiple synchronization signals provided to sensors of RF match during plasma processing, according to one or more embodiments.

[0044]

[0054] 8A illustrates a method 800 for using an RF plasma processing system (e.g., plasma processing system 10 of FIGS. 1 and 2 ) according to certain embodiments. Method 800 is performed by processing logic including hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, processing device, etc.), software (e.g., instructions running on a processing device, a general-purpose computer system, or a dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, method 800 is performed in part by a controller device (e.g., system controller 126 of FIGS. 1 and 2 and / or RF matching controller 302 of FIG. 3A ). In some embodiments, a non-transitory storage medium stores instructions (i.e., an algorithm) that, when executed by the controller device, cause the controller device to perform method 800.

[0045]

[0055] For ease of explanation, method 800 is shown and described as a series of steps. However, steps according to the present disclosure may occur in various orders and / or concurrently with other steps not shown and described herein. Furthermore, in some embodiments, not all illustrated steps are performed to implement method 800 in accordance with the disclosed subject matter. Additionally, those skilled in the art will understand and appreciate that method 800 may alternatively be represented as a series of interrelated states via a state diagram or state events.

[0046]

[0056] At block 802 of the method 800, the RF generator 171 supplies an RF signal through the RF match 172 to an electrode assembly disposed within the plasma processing system 10 to form the plasma 101 within the process space 129. The RF signal is supplied to the electrode assembly at a first match point set by the RF match 172. As explained above, the first match point is used by the RF match to vary the impedance between the source (e.g., the RF signal) and the impedance of the plasma processing system 10 (e.g., the impedance of a load created by the plasma 101) so that the impedance is substantially equal, but will not be close enough to the desired match point because the load impedance value will initially vary. In some embodiments, the settings of various components within the RF match 172, such as the variable capacitors within the tuning circuit 312, used to achieve the first match point are based on a prior calibration process or similar system knowledge and are pre-set and stored in memory for use as a starting point by the controller 302 within the RF match 172.

[0047]

[0057] In block 804 of the method 800, the PV waveform generator 175 generates pulses, each having a pulse period T, to electrodes disposed within the plasma processing system 10, as shown in FIGS. 1-2, 5A-5B, and 5D. pThe processing system 10 provides a voltage waveform 501 including multiple pulses 501A having a frequency of 100 kHz to 1500 kHz, such as 500 kHz to 500 kHz. The multiple pulses 501A are provided simultaneously with an RF waveform 521 (FIGS. 5B and 5D) provided to an electrode in the processing system 10 to form the plasma 101 during block 802. In one processing example, the frequency of the pulses provided in the voltage waveform in block 804 may be between 50 and 500 kHz, and the ion current phase of each pulse (e.g., the low-level portion of the pulse) may have a duration that is between 5% and 95% of the period of the pulse, e.g., between 50% and 95% of the period of the pulse.

[0048]

[0058] At block 806 of the method 800, the RF match 172 receives a synchronization signal 541 from the PV waveform generator 175 (FIG. 5B) and / or a synchronization signal 543 from the RF generator 171 (FIG. 5D). In one embodiment, during block 806, the RF generator 171 and the PV waveform generator 175 provide a synchronization signal, such as a TTL signal, to the RF match 172. The synchronization signal is used to synchronize measurements of one or more electrical parameters by the input sensor 116 and the output sensor 117 and may be used as a trigger to the RF match 172 to determine the impedance of the plasma processing system 10.

[0049]

[0059] As shown in FIGS. 5A-5B, in block 808 of method 800, output sensor 117 samples a first set of impedance-related data during data interval 1A of plasma processing system 10 over a first time period, as indicated by the width of the vertically oriented rectangular box shown in FIG. 5A. The first set of impedance-related data may be a set of one or more impedance-related data parameters used to determine impedance. As discussed above and generally used herein and hereinafter, a set of impedance-related data (e.g., first set of impedance-related data) may include data related to at least one of voltage, current, phase, power, and combinations thereof. Due to instability in the impedance of the complex load due to application of the voltage waveform provided during block 804, it is desirable that the first impedance measurement, and all subsequent measurements, be collected at one or more desired times within a portion of the repetition period of pulse 501A provided to voltage waveform 501. In some embodiments, the first time period begins after a first delay time T1 triggered by the synchronization signal provided during block 806.

[0050]

[0060] As shown in FIG. 5B , the synchronization signal 541 of the PV waveform generator 175 is synchronized with the voltage waveform 501. The synchronization signal 541 of the PV waveform generator 175 synchronizes the input sensor 116 and the output sensor 117. A first portion of the synchronization signal 541 of the PV waveform generator 175 may also be used to trigger the first delay T1. As one example, as shown in FIG. 5B , the first portion of the synchronization signal 541 of the PV waveform generator 175 provided in block 806 may be generated by detecting a rising edge of the synchronization signal 541 of the PV waveform generator 175. As another example, the first portion of the synchronization signal provided in block 806 may be generated by detecting a falling edge of the synchronization signal 541 of the PV waveform generator 175. Alternatively, the first delay T1 may be triggered by a significant change in the characteristics of the voltage waveform 501 or the RF waveform 521 ( FIGS. 5B and 5D ) detected by a sensor of the RF match 172. After the first delay time T1, the output sensor 117 samples a first set of impedance-related data during data interval 1A of the plasma processing system 10 over a first period of time and reports them to the RF match controller 302. In some cases, the first set of impedance-related data collected by the output sensor 117 may be internally processed to form one or more average values ​​of the sensed electrical parameters over the first period of time. The formed average values ​​are sent to the match controller 302 for use in block 809.

[0051]

[0061] As shown in FIG. 5D , the RF generator 171 may transmit a synchronization signal 543 that synchronizes with the voltage waveform 501 and the RF waveform 521. The RF generator 171 synchronization signal 543 synchronizes the input sensor 116 and the output sensor 117. In embodiments, the pulse of the RF generator 171 synchronization signal 543 is longer than the PV waveform generator 175 synchronization signal 541 ( FIG. 5B ). In some embodiments, the synchronization signal from the RF generator 541 is a macropulse having a period of 100 μs to 1 second, and the PV waveform generator synchronization pulse period is 0.1 μs to 100 μs. Additionally, a first portion of the RF generator 171 synchronization signal 543 may be used to trigger a first delay T1. In one example, as shown in FIG. 5D , the first portion of the RF generator 171 synchronization signal 543 provided during block 806 may be generated by detecting a rising edge of the RF generator 171 synchronization signal 543. In another example, the first portion of the synchronization signal provided during block 806 may be generated by detecting a falling edge of the synchronization signal 543 of the RF generator 171. Alternatively, the first delay T1 may be triggered by a significant change in the characteristics of the voltage waveform 501 or the RF waveform 521 (FIGS. 5B and 5D) detected by a sensor of the RF match 172. After the first delay time T1, the output sensor 117 samples a first set of impedance-related data during data interval 1A of the plasma processing system 10 over a first period of time and reports them to the RF match controller 302. Optionally, the first set of impedance-related data collected by the output sensor 117 may be internally processed to form one or more average values ​​of the detected electrical parameters over the first period of time. The formed average values ​​are sent to the match controller 302 for use in block 809.

[0052]

[0062] To determine the composite impedance parameters, each pulse duration T p Although two data intervals are shown in FIG. 1, the number of data intervals in each pulse period is not limited.

[0053]

[0063] In block 809 of method 800, the RF matching controller 302 determines a first impedance of the plasma processing system 10 based on the impedance-related data collected during data interval 1A. In some embodiments of block 809, the first impedance is determined by averaging the sampled impedance of the load in the process space 129 (i.e., the impedance of the plasma processing system 10) measured by the output sensor 117 during a first time period, illustrated as data interval 1A in FIGS. 5A and 5C. In one example, the first time period occurs during the sheath collapse phase, as shown in FIG. 5A. In some embodiments, the first impedance is determined by using the data (e.g., voltage, current, and / or phase) collected by the output sensor 117 during block 808 and a look-up table or an empirically determined equation stored in memory of the RF matching controller 302 that equates the impedance-related data to a known or empirically determined impedance.

[0054]

[0064] At block 810 of method 800, a second set of impedance-related data is collected during data interval 2A by sampling data over a second period of time after a second delay time T2 has elapsed, as shown in FIGS. 5A-5B. The second set of impedance-related data may be a set of one or more impedance-related data parameters used to determine impedance. The second set of impedance-related data may include at least one of the impedance-related parameters found in the first set of impedance-related data. As discussed above, in some embodiments, the second delay time T2 is triggered simultaneously with (i.e., simultaneously with) the first delay time T1, and the time delay for collecting the impedance-related data during data interval 2A is longer than the first delay time T1. In one example, as shown in FIGS. 5A and 5B, the second set of impedance-related data collected during data interval 2A may be determined over a second period of time occurring during the ionic current phase of the pulse delivered within the voltage waveform. The second period for data collection, i.e., data interval 2A, may be of the same or different duration as the first period for data collection, data interval 1A. In one example, the durations of the first and second periods used to collect data interval 1A and data interval 2A are between 0.1 and 1 second. The first delay T1 and second delay T2 may have durations between 0.005 μs and 10 μs.

[0055]

[0065] At block 811 of the method 800, the RF matching controller 302 determines a second impedance of the plasma processing system 10 based on the impedance-related data collected during data interval 2A. The second impedance is determined similarly to the first impedance using the output sensor 117. In some cases, the second impedance is determined using data (e.g., voltage, current, and / or phase) collected by the output sensor 117 and a look-up table or an empirically determined formula stored in the memory of the RF matching controller 302. In some embodiments, the first delay time T1 and the second delay time T2 are configured to both fall within one or more portions of the same pulse 501A. However, the first delay time T1 and the second delay time T2 can be configured alternately so that the collection of impedance-related data during data interval 1A and data interval 2A falls within the same portions of two separate pulses 501A. In one example, the first delay time T1 and the second delay time T2 are set so that data samples are both collected at a point within the ion current phase of a subsequent pulse 501A, or even at the same point within two or more pulses in a series of pulses 501A, where the data is collected within a pulse period T p The signals are collected at intervals offset by an integer multiple of (FIG. 5A), which can be 1 or greater.

[0056]

[0066] 5A-B, in block 812 of method 800, a composite impedance parameter is determined based on the determined first and second impedances determined during blocks 808-811. For example, the composite impedance parameter may be determined by taking a weighted average between the first impedance and the second impedance determined in blocks 809 and 811. Based on the composite impedance parameter, the match point of RF matching 172 is set relative to the measured impedance of the composite load, for updating based on the composite impedance. In other words, the first match point of RF matching 172 is updated to the second match point based on the composite impedance by making tuning adjustments to one or more components in RF matching 172, for example, one or more of the variable capacitors in tuning circuit 312 (e.g., capacitors C1 and / or C2 in FIG. 3B). Each pulse period T P The number of data intervals in is not limited. For example, impedance-related data may be collected in the same pulse period as data interval 1A and data interval 2A and used to determine the first composite impedance parameter. In some embodiments, the user can define how many data intervals are used to average the collected data (e.g., 50 data intervals or 100 data intervals, etc.). In one example, the third data interval 3A after the third delay T3 is the same as the first data interval of each pulse period T P In another example, in the case of a triple-level pulse (not shown), impedance-related data may be collected over a third data interval 3A after a third delay T3, which may be at a third power level within the pulse. In one example, the data collected during data intervals 1A, 2A, and 3A is averaged and used to adjust the match point in a subsequent step.

[0057]

[0067] At block 814 of method 800, the match point is adjusted by RF match 172 to achieve a second match point associated with the impedance of the composite load determined by output sensor 117. For example, RF match controller 302 may adjust tuning circuit 312 to achieve the second match point, thereby enabling RF match 172 to adjust the match point as the load impedance varies during plasma processing.

[0058]

[0068] During block 816, optionally, after determining the composite impedance during block 812 and adjusting the match to the second match point, RF match controller 302 further fine-tunes the impedance of RF match 172 to improve the impedance match of the RF waveform. During optional block 816, input sensor 116 samples impedance-related data of the RF waveform and reports them to controller 302. RF match controller 302 then further updates the second match point to a third match point and further adjusts tuning circuit 312 based on the impedance of the RF waveform measured by input sensor 116. In one example, the third match point is used to adjust the match so that RF generator 171 sees a 50 ohm load. In other embodiments, the third match point may be used to determine a new weighted impedance based on the impedance-related data sampled during Data 1A and 2A.

[0059]

[0069] In some embodiments, RF match 172 may maintain the second match point for a predetermined period of time. For example, because the on-time of the PV waveform is typically much shorter than the motor response time for adjusting the impedance of the capacitive element in RF match 172, the second match point may remain unchanged for one or more PV waveform bursts. This process may be repeated for each burst on-time of the PV waveform. In some embodiments, the rate at which the third match point is adjusted is slower than the rate at which the second match point is adjusted to avoid fluctuations in the match point. In some configurations, the third match point is selected based on a rolling average of measurements taken by input sensor 116 during block 816.

[0060]

[0070] In some embodiments, if one or more plasma processing variables are adjusted during a plasma process performed in a plasma processing chamber, it may be desirable to re-perform the steps found in one or more of blocks 802-814 (e.g., perform blocks 806-814 at least one more time) before re-performing the step in block 816. Typical plasma processing variables may include RF signal power level, chamber pressure, process gas composition, process gas flow rate, voltage waveform characteristics (e.g., frequency, pulse on time / duty cycle, voltage, etc.).

[0061]

[0071] In some embodiments of the present disclosure, the system controller 126 and the RF match controller 302 are configured to collect the collected impedance-related data and / or calculated impedance data during one or more of various data intervals, store the impedance-related data and / or calculated impedance data in memory, generate reports or files, and / or display the impedance-related data and / or calculated impedance data on a graphical user interface (GUI) of a user PC ( FIG. 3A ) to allow a user to view and determine the status of the plasma processing system. In one example, the sensors 116, 117 and the RF match controller 302 are used to provide information to the system controller 126, which then enables algorithms running on the system controller 126 to generate one or more real-time plots of the impedance-related data and / or calculated impedance data, allowing a user to use the generated information for optimization and diagnostic purposes. The plots may include time-domain plots of impedance, voltage, current, phase, or other useful measurements (e.g., match temperature, chamber pressure, gas flow rate, frequency). These may be provided to the user via a display, stored in an electronic file, and / or printed.

[0062] Additional Processing Examples

[0072] 8B-8C illustrate a method 817 for using an RF plasma processing system (e.g., plasma processing system 10 of FIGS. 1 and 2 ) according to certain embodiments. Method 817 is performed by processing logic including hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, a processing device, etc.), software (e.g., instructions executing on a processing device, a general-purpose computer system, or a dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, method 817 is performed in part by a controller device (e.g., system controller 126 of FIGS. 1 and 2 and / or RF matching controller 302 of FIG. 3A ). In some embodiments, a non-transitory storage medium stores instructions that, when executed by the controller device, cause the controller device to perform method 817. For simplicity of explanation, method 817 is illustrated and described as a series of steps. However, steps according to the present disclosure may occur in various orders and / or concurrently with other steps not presented and described herein. Furthermore, in some embodiments, not all illustrated steps are performed to perform method 817 in accordance with the disclosed subject matter. Additionally, those skilled in the art will understand and appreciate that the methodology 817 could alternatively be represented as a series of interrelated states via a state diagram or state events.

[0063]

[0073] In block 818 of method 817, RF generator 171 supplies an RF signal through RF match 172 to an electrode assembly disposed within plasma processing system 10 to form plasma 101. The RF signal is supplied to the electrode assembly at a first match point set by RF match 172 in the same manner as described in block 802 of method 800 above.

[0064]

[0074] In block 820 of the method 817, the PV waveform generator 175 generates a plurality of pulses, each having a pulse period T PA voltage waveform 501 including a plurality of pulses having a voltage waveform of a magnitude of 0.01 V is applied to an electrode disposed within the plasma processing system 10. Similar to that described above in block 804, during block 818, the plurality of pulses are applied simultaneously with an RF signal applied to an electrode within the processing system 10 to form the plasma 101.

[0065]

[0075] In block 822 of method 817, RF matching 172 receives one or more synchronization signals from RF generator 171 and / or PV waveform generator 175. The synchronization may be provided and used in the same manner as described above in block 806 of method 800.

[0066]

[0076] 5A-5C, in block 824 of method 817, output sensor 117 samples a first set of impedance-related data during data interval 1A of plasma processing system 10 over a first period of time and reports them to RF matching controller 302. The first set of impedance-related data collected during data interval 1A is sampled and / or processed in the same manner as described above in block 808 of method 800.

[0067]

[0077] 5A-5C, in block 826 of method 817, the RF matching controller 302 determines a first impedance of the plasma processing system 10 based on the impedance-related data collected during data interval 1A, as also discussed above in block 809 of method 800. For example, the RF matching controller 302 may determine the first impedance by averaging the sampled impedance-related data collected during data interval 1A.

[0068]

[0078] 5A-5C, in block 828 of method 817, output sensor 117 samples a second set of impedance-related data collected during data interval 2A over a second time period and reports them to RF matching controller 302. The second set of impedance-related data collected during data interval 2A is sampled in the same manner as described above in block 810 of method 800.

[0069]

[0079] 5A-5C, in block 830 of method 817, the RF matching controller 302 determines a second impedance of the plasma processing system 10 based on the impedance-related data collected during data interval 2A, as also discussed above in block 811 of method 800. For example, the RF matching controller 302 may determine the second impedance by averaging the sampled impedance-related data collected during data interval 2A.

[0070]

[0080] 5C, in block 832 of method 817, after collecting impedance-related data during data interval 1A and data interval 2A, the RF matching controller 302 may sample a third set of impedance-related data during data interval 1B of the plasma processing system 10 sampled over a third period of time after a third delay T3. The third delay T3 may be triggered similarly to the first delay T1 and the second delay T2. In one example, the third delay T3 may be triggered by adding a pulse period T to the first delay. p The third set of impedance-related data may be a set of one or more impedance-related data parameters used to determine impedance. The third set of impedance-related data may include at least one of the impedance-related parameters as found in the first and second sets of impedance-related data.

[0071]

[0081] 5A-5C, in block 834 of method 817, the RF matching controller 302 determines a third impedance of the plasma processing system 10 based on the data collected during data interval 1B. For example, the RF matching controller 302 may determine the third impedance by averaging the sampled impedance-related data collected during data interval 1B.

[0072]

[0082] In block 836 of method 817, a fourth set of impedance-related data is collected during data interval 2B by sampling for a fourth period after a fourth delay T4, as shown in FIG. 5C. The fourth delay T4 may be triggered similarly to the first delay T1, the second delay T2, and the third delay T3. The fourth delay T4 is equal to the second delay T2 plus the period of the pulse. In some embodiments, an error correction time may be added to the third delay T3 and the fourth delay T4 based on the characteristics measured by the output sensor 117. The fourth set of impedance-related data may be a set of one or more impedance-related data parameters used to determine the impedance. The fourth set of impedance-related data may include at least one of the impedance-related parameters found in the first, second, and third sets of impedance-related data.

[0073]

[0083] 5A-5C, in block 838 of method 817, the RF matching controller 302 determines a fourth impedance of the plasma processing system 10 based on the impedance-related data collected during data interval 2B. For example, the RF matching controller 302 may determine the fourth impedance by averaging the sampled impedance-related data collected during data interval 2B.

[0074]

[0084] As shown in FIG. 5C, in block 840 of method 817, a fifth set of impedance-related data is collected during data interval 1C of the plasma processing system 10 by sampling over a fifth period after a fifth delay T5. The fifth delay T5 may be triggered similarly to the first through fourth delays T1 through T4. The fifth delay T5 is equal to the first delay T1 plus twice the period of the pulse. As discussed above, an optional error factor may be added to the fifth delay T5. The fifth set of impedance-related data may be a set of one or more impedance-related data parameters used to determine the impedance. The fifth set of impedance-related data may include at least one of the impedance-related parameters found in the first, second, third, and fourth sets of impedance-related data.

[0075]

[0085] 5A-5C, in block 842 of method 817, the RF matching controller 302 determines a fifth impedance of the plasma processing system 10 based on the impedance-related data collected during data interval 1C. For example, the RF matching controller 302 may determine the fifth impedance by averaging the sampled impedance-related data collected during data interval 1C.

[0076]

[0086] As shown in FIG. 5C , in block 844 of method 817, a sixth set of impedance-related data collected during data interval 2C of the plasma processing system 10 is sampled over a sixth period after a sixth delay T6. The sixth delay T6 may be triggered similarly to the first through fifth delays T1 through T5. The sixth delay T6 is equal to the second delay T2 plus twice the period of the pulse. As discussed above, an optional error factor may be added to the sixth delay T6. The sixth set of impedance-related data may be a set of one or more impedance-related data parameters used to determine the impedance. The sixth set of impedance-related data may include at least one of the impedance-related parameters found in the first, second, third, fourth, and fifth sets of impedance-related data.

[0077]

[0087] 5C, in block 846 of method 817, the RF matching controller 302 determines a sixth impedance of the plasma processing system 10 based on the impedance-related data collected during data interval 2 C. For example, the RF matching controller 302 may determine the sixth impedance by averaging the sampled impedance-related data collected during data interval 2 C.

[0078]

[0088] In some embodiments, an error correction time may be added to the time delay by the RF match controller 302 to ensure that the time delay and subsequent measurements occur within a desired portion of each subsequent voltage pulse based on the characteristics measured by the output sensor 117. In some embodiments, the correction time may be equal to or greater than the pulse period T pThis may be a small percentage (e.g., <10%) of the total pulse width, but can be adjusted by an optimization process. This optimization process is performed to minimize the variability in the data used to determine the impedance of the load based on similar measurements taken within the same portion of the pulses. In one example, multiple data measurements are taken at slightly shifted intervals within a desired portion of the pulses. For example, data intervals 1A, 1B, and 1C are shifted from one another by a fixed time (e.g., 1 μs). During this process, the variability in the measured data (e.g., current, voltage, etc.) is determined for each measured data interval 1A, 1B, and 1C to find which measurement had the least variability so that subsequent measurements can be taken with the same corrected time delay within each subsequent pulse.

[0079]

[0089] As mentioned above, the collection of impedance-related data may be triggered by the rising or falling edge of a synchronization signal from either the RF generator 171 and / or the PV waveform generator 175. Each pulse voltage T P Multiple data intervals of impedance-related data may be collected during each pulse period T P The number of data intervals in is not limited. Also, the duration / width of each data interval is not limited. The impedance-related data collected during each data interval may include voltage, current, phase, etc. A composite impedance parameter may then be determined based on the impedance-related data, which may be used to adjust the match point of RF match 172. In one example, the collection of impedance-related data may be triggered by a rising edge of a synchronization signal transmitted by RF generator 171.

[0080]

[0090] At block 848 of the method 817, a composite impedance parameter is determined based on the determined first through sixth second impedances. Based on the composite impedance parameter, a match point of the RF match 172 is updated based on the composite impedance. In other words, the first match point of the RF match 172 is updated to a second match point based on the composite impedance.

[0081]

[0091] In one example, the composite impedance is a combination of the first through sixth impedances. The composite impedance may be determined by taking a weighted average of the first through sixth impedances. In another example, a first composite impedance determined by combining the first and second impedances may be combined with a second composite impedance determined by combining the third and fourth impedances, and a third composite impedance determined by combining the fifth and sixth impedances is used as the composite impedance. This process continues for subsequent pulse periods T p The process may be repeated for each of the first and second impedances. As described above, the first composite impedance may be determined by taking a weighted average of the first and second impedances. The second composite impedance may be determined by taking a weighted average of the third and fourth impedances. The third composite impedance may be determined by taking a weighted average of the fifth and sixth impedances. The composite impedance may then be determined by taking a weighted average of the first through third composite impedances.

[0082]

[0092] Alternatively, any number of pulse periods occurring during the burst-on time of the PV waveform may be used. For example, two pulses may be used to determine the composite impedance parameter, and the composite impedance may be determined based on the first through fourth sets of data intervals 1A through 2B. In another example, the pulses used to determine the composite impedance parameter may not be consecutive. For example, the composite impedance parameter may be determined based on the first and second sets of impedance-related data collected during data intervals 1A and 2A and the fifth and sixth sets of impedance-related data collected during data intervals 1C and 2C.

[0083]

[0093] In block 850 of the method 817, based on the composite impedance parameters, the match point of the RF match 172 is updated based on the composite impedance. In other words, the first match point of the RF match 172 is updated to the second match point based on the composite impedance.

[0084]

[0094] During optional block 852, after determining the composite impedance during block 848, RF matching controller 302 may optionally further fine-tune the impedance of RF match 172 to improve the impedance match of the RF waveform. Input sensor 116 samples impedance-related data of the RF waveform and reports them to controller 302. RF matching controller 302 then further updates the match point and further adjusts tuning circuit 312 based on the impedance of the RF waveform. These processes may be repeated for each burst-on time of the PV waveform.

[0085]

[0095] FIG. 6 illustrates an example of multiple synchronization signals configured to trigger different components of RF matching 172. As described above, impedance measurements may be determined by each sensor after a delay triggered by the synchronization signal. Each sensor may receive the same or different synchronization signals. In some embodiments, the input sensor 116 and the output sensor 117 may use different synchronization signals to trigger data collection. For example, synchronization signal 543 of RF generator 171 may be sent to input sensor 116 and used to trigger input sensor 116 to collect impedance-related data, while synchronization signal 541 of PV waveform generator 175 may be sent to output sensor 117 and used to trigger output sensor 117 to collect impedance-related data (or vice versa).

[0086]

[0096] The synchronization signal 541 of the PV waveform generator 175 may include multiple pulses 555. For example, a rising edge of the pulse 555 may trigger the output sensor 117 to collect impedance-related data of the plasma processing system 10, determine an impedance measurement (i.e., a composite impedance parameter), and send the composite impedance parameter to the RF matching controller 302. The RF matching controller 302 may then determine an updated match point and adjust the RF matching 172 to achieve the updated match point. In other words, as described above, the impedance-related data may be collected after a delay triggered by each rising edge, a composite impedance measurement may be determined during the pulse 555 of the synchronization signal 541 of the PV waveform generator 175, and the match point of the RF matching 172 may be updated during the pulse 555. The composite impedance measurement may be determined during each pulse period 532 of the synchronization signal 541 of the PV generator waveform 175. A first measurement may be determined during the first pulse, a second measurement may be determined during the second pulse, a third measurement may be determined during the third pulse, etc. Meanwhile, the falling edge of the synchronization signal 541 of the PV waveform generator 175 may be used to trigger the output sensor 117 to collect impedance-related data and determine a composite impedance parameter during the pause time between each pulse 555.

[0087]

[0097] The synchronization signal 543 of the RF generator 171 may include multiple pulses 557. The rising edges of the pulses 557 may trigger the input sensor 116 to sample the impedance of the RF waveform 521 ( FIGS. 5B and 5D ), which is used to further update the match point of the RF match 172 determined based on the impedance-related data sampled by the output sensor 116. For example, after updating the match point of the RF match 172 based on the impedance measurements of the output sensor, the match point is further updated during each pulse period 530 based on the impedance sampled by the input sensor 116. Meanwhile, the falling edges of the pulses 557 may be used to trigger the input sensor 117 to collect impedance-related data of the RF waveform 521 during the pause times between pulses of the synchronization signal 543 of the RF generator 171.

[0088]

[0098] 7 and 9 show a method for using an RF match 172 to sample the change in impedance of a load created by the plasma 101 when a pulsed RF signal is used to form the plasma 101.

[0089]

[0099] FIG. 7A illustrates multiple RF pulses delivered to an electrode during plasma processing according to one or more embodiments. Referring to FIG. 7A, an output sensor of RF matching 172 collects impedance-related data during a portion of an RF waveform generated by RF generator 171 in pulsed mode. In one example of pulsed mode, as shown in FIG. 7A, plasma 101 is generated by sequentially delivering a first RF pulse state and a second RF pulse state. The first RF pulse state is delivered at a first power level state, and the second pulse state is delivered at a second power level state. In one example, as shown in FIG. 7A, the first power level state is at a higher power level than the second power level state, and a transition occurs from the first power level state to the second power level state at time t0. In other embodiments, the first power level state can be lower than the second power level state.

[0090]

[0100] In one embodiment, RF matching 172 is performed during data interval 1 of the plasma processing system 10, during which the RF waveform transitions between the second RF pulse state and the first RF pulse state. RF and baseline data sampled while the RF waveform is in the second RF pulse state (or the first RF pulse state) interval 2 RF and determine the match point. For example, a scanning impedance of the plasma processing system 10 is sampled between a first time t1 and a second time t2 while the RF waveform transitions from a first RF pulse state to a second RF pulse state (or vice versa). Baseline impedance data is sampled at time t3 while the RF waveform is in the first state.

[0091]

[0101] The scanned impedance of the plasma processing system 10 may be sampled by the output sensor 117 and reported to the RF match controller 302 in the same manner as described above. Data Interval 1 RF Sampling of the impedance-related data collected during data interval 2 is triggered by a first time delay d1. RF Sampling of the impedance-related data collected during t1 may be triggered by a second time delay d2. The first time delay d1 and the second time delay d2 may be triggered in a manner similar to that described above. The first time delay d1 may be a variable time delay that is shifted between state changes based on the characteristics sampled by the input sensor 116 to ensure that data 1 includes only impedances during transitions between states. The second delay d2 may be fixed. Furthermore, based on the impedance or other characteristics of the RF waveform sampled by the output sensor 117, the duration between the first time t1 and the second time t2 may be adjusted between state changes to ensure that the sampled impedance is only sampled during transitions between states.

[0092]

[0102] 7B shows an example of resistance (R) and reactance (X) measurements resulting from the application of RF pulses to a composite load as a function of time during plasma processing, according to one or more embodiments. Referring to FIG. 7B, input sensor 116 and output sensor 117 are sensors configured to measure parameters used to determine the composite impedance (X). The sensors measure the resistance of plasma processing system 10 and the capacitance of a capacitive element (X C ) or inductive element (X L ) simultaneously. Based on the resistance (i.e., the real component) and the non-real component, the sensor may then scan the impedances and report them to the controller 302.

[0093]

[0103] 9 illustrates a method 900 of using an RF plasma processing system when multiple RF pulses are delivered to an electrode of the plasma processing system, according to certain embodiments. For simplicity of explanation, method 900 is illustrated and described as a series of steps. However, steps according to the present disclosure may occur in various orders and / or simultaneously with other steps not shown and described herein. Furthermore, in some embodiments, not all illustrated steps are performed to implement method 900 in accordance with the disclosed subject matter. Additionally, those skilled in the art will understand and appreciate that method 900 may alternatively be represented as a series of interrelated states via a state diagram or state events.

[0094]

[0104] At block 902 of method 900, plasma 101 is generated in process space 129 of plasma processing system 10. As described above, in one embodiment, generating plasma 101 includes providing an RF waveform that sequentially provides a series of first RF pulses each separated by a second RF pulse. As shown in Figures 7A-B, the first and second RF pulses are generated by RF generator 171, which provides an RF signal to an electrode assembly via RF match 172. The first RF pulse is generated at a first power level state 1.RF (i.e., State 1), and the second pulse is delivered at a second power level, State 2 RF (i.e., State 2). Generally, the RF waveform is delivered to the electrode assembly at a first match point set by the RF match 172. In some embodiments, the settings of various components within the RF match 172, such as the variable capacitors within the tuning circuit 312, used to achieve the first match point are based on a prior calibration process or similar system knowledge and are pre-set and stored in memory for use as a starting point by the controller 302 within the RF match 172.

[0095]

[0105] 7A-B, in block 904 of method 900, a transition region between the first and second RF pulses is determined by the controller 302 of the RF matching 172. In some embodiments, the beginning or end of the transition region is used by the matching controller 302 as a trigger to detect impedance-related data during a portion of the RF waveform that includes the first and second RF pulses. In one example, the trigger is detected at the beginning of the transition region, seen at time t1, as shown in FIGS. 7A-7B.

[0096]

[0106] 7A-B, in block 906 of method 900, RF match 172 determines a scan impedance of plasma processing system 10 during a transition region between the first RF pulse and the second RF pulse. The scan impedance is created by detecting one or more of the impedance-related data collected by output sensor 117 during a data interval of a desired length within at least a portion of the transition region (e.g., time t2 minus time t1). RF match controller 302 may determine the scan impedance value by averaging the sampled impedance-related data collected during the defined data interval.

[0097]

[0107] 7A-B, in block 908 of the method 900, the RF match 172 determines a baseline impedance of the plasma processing system 10 during either the first pulse or the second pulse. The baseline impedance is generated by detecting one or more impedance-related data with the output sensor 117 during a portion of the first or second pulse (e.g., time t3).

[0098]

[0108] 7A-B, in block 910 of method 900, the controller 302 of the RF matching 172 determines a composite impedance parameter based on the detected scanning impedance and the baseline impedance. For example, the RF matching 172 may determine the composite impedance parameter by taking a weighted average between the scanning impedance and the baseline impedance.

[0099]

[0109] At block 912 of method 900, RF matching 172 updates its matching parameters by updating its matching point based on the composite impedance and adjusts tuning circuit 312 accordingly. In other words, the first matching point of RF matching 172 is updated to a second matching point based on the composite impedance by making tuning adjustments to one or more components in RF matching 172, for example, one or more of the variable capacitors in tuning circuit 312 (e.g., capacitors C1 and / or C2 in FIG. 3B ).

[0100]

[0110] During block 914, after determining the composite impedance during block 912, the RF matching controller 302 further fine-tunes the impedance of the RF matching 172 to improve the impedance match of the RF waveform. The input sensor 116 samples impedance-related data of the RF waveform and reports them to the controller 302. The RF matching controller 302 then further updates the match point to a third match point by further adjusting the tuning circuit 312 based on the detected impedance of the RF waveform. This process may be repeated for each portion of the RF waveform. In various embodiments, other possible options for updating the variable capacitor positions of the RF matching include using theoretical calculations or look-up tables based on the composite impedance parameters.

[0101]

[0111] As described above, embodiments of the present disclosure include apparatus and methods for synchronizing and controlling the delivery of RF bias voltage to one or more electrodes disposed within a plasma processing chamber to better control the efficient delivery of RF power to a plasma formed within a processing region of the plasma processing chamber.

Claims

1. 1. A method for processing a substrate in a plasma processing system, comprising: supplying an RF signal by an RF generator through an RF match to an electrode assembly disposed within the plasma processing system, wherein the RF match is set to a first match point while supplying the RF signal; applying a voltage waveform to the electrode assembly disposed within the plasma processing system by a waveform generator while the RF signal is applied to the electrode assembly; receiving a synchronization signal from the RF generator or the waveform generator by the RF matching; measuring a first set of impedance-related data of the plasma processing system over a first period of time with an output sensor of the RF match, the first period of time beginning after a first delay triggered by a first portion of a first waveform pulse of the synchronization signal; measuring a second set of impedance-related data of the plasma processing system over a second time period with the output sensor of the RF match, the second time period starting after a second delay triggered by the first portion of the first waveform pulse of the synchronization signal; calculating a composite impedance parameter by the RF matching based on the first set of measured impedance-related data and the second set of measured impedance-related data; adjusting a matching parameter in the RF match based on the calculated synthetic impedance parameter to achieve a second match point; A method comprising:

2. The method of claim 1 , wherein the first period and the second period have equal duration.

3. The method of claim 1 , wherein calculating the composite impedance parameter comprises calculating a weighted average between the first set of impedance-related data and the second set of impedance-related data.

4. 2. The method of claim 1, wherein the synchronization signal from the RF generator and the synchronization signal from the waveform generator are transistor-transistor logic (TTL) synchronization signals.

5. measuring the impedance of the RF signal with an input sensor of the RF match after adjusting the match parameters within the RF match; further adjusting the matching parameters in the RF match based on the measured impedance of the RF signal to achieve a third match point; The method of claim 1 further comprising:

6. 2. The method of claim 1, wherein the first set of impedance-related data is determined by averaging the first set of impedance-related data measured during the first time period, and the second set of impedance-related data is determined by averaging the set of impedance-related data measured during the second time period.

7. 10. The method of claim 1, wherein the first period of time occurs while the plasma processing system is in a sheath collapse phase of a process and the second period of time occurs while the plasma processing system is in an ion current phase of a process.

8. The method of claim 1 , wherein the first period and the second period occur during the same period of the voltage waveform.

9. measuring a third set of impedance-related data of the plasma processing system over a third period of time with the output sensor of the RF match, the third period of time beginning after a third delay that begins simultaneously with the first delay; measuring a fourth set of impedance-related data of the plasma processing system over a fourth time period with the output sensor of the RF match, the fourth time period starting after a fourth delay that starts simultaneously with the first delay; calculating the composite impedance parameter by the RF matching based on the first set of measured impedance-related data, the second set of measured impedance-related data, the third set of measured impedance-related data, and the fourth set of measured impedance-related data; The method of claim 1 further comprising:

10. 10. The method of claim 9, wherein the first period and the second period occur during a first period of the voltage waveform, and the third period and the fourth period occur during a second period of the voltage waveform.

11. 1. A method for processing a substrate in a plasma processing system, comprising: generating a plasma in a processing space of the plasma processing system, generating a plasma by delivering an RF waveform comprising sequentially delivering a first RF pulse and a second RF pulse; the first RF pulse comprises a first RF power level and the second RF pulse comprises a second RF power level; generating a plasma in which the sequentially applied first and second RF pulses are formed by applying an RF signal to an electrode assembly of the plasma processing system through RF matching; Detecting a transition region between the first RF pulse and the second RF pulse; determining a scanning impedance of the plasma processing system during the transition region between the first RF pulse and the second RF pulse; determining a baseline impedance of the plasma processing system during the first RF pulse or the second RF pulse; calculating a composite impedance parameter based on the scanned impedance and the baseline impedance; A method comprising:

12. The method of claim 11 , wherein the second RF power level is zero or less than the first RF power level.

13. 13. The method of claim 12, wherein the scan impedance is an average impedance of the plasma processing system during a rising or falling edge extending between the first RF power level and the second RF power level.

14. 14. The method of claim 13, wherein the baseline impedance is the impedance of the plasma processing system at the second RF power level.

15. 14. The method of claim 13, wherein the baseline impedance is the impedance of the plasma processing system at the first RF power level.

16. the RF match is set to a first match point while applying a first RF pulse of the RF waveform through the RF match; The method comprises: adjusting a match parameter in the RF match based on the calculated composite impedance parameter to achieve a second match point different from the first match point. The method of claim 11 further comprising:

17. 1. A plasma processing system comprising: an RF generator configured to supply an RF signal to an electrode assembly disposed within the plasma processing system through an RF match, wherein the RF match is set to a first match point while supplying the RF signal; a voltage waveform generator configured to supply a voltage waveform to the electrode assembly disposed within the plasma processing system while the RF signal is supplied to the electrode assembly, the RF matching comprising: Input sensors, Output sensor, an RF matching controller; and a memory for storing a program executed within the RF match controller, the program, when executed, causing the RF match controller to: receiving a synchronization signal from the RF generator or the waveform generator by the RF matching; measuring a first set of impedance-related data of the plasma processing system using the output sensor over a first period of time, the first period of time beginning after a first delay triggered by a first portion of a first waveform pulse of the synchronization signal; measuring a second set of impedance-related data of the plasma processing system over a second time period using the output sensor of the RF match, the second time period starting after a second delay triggered by the first portion of the first waveform pulse of the synchronization signal; calculating, by the RF matching controller, a composite impedance parameter based on the first set of measured impedance-related data and the second set of measured impedance-related data; adjusting a matching parameter in the RF match based on the calculated synthetic impedance parameter to achieve a second match point; memory containing instructions to execute a voltage waveform generator including: A plasma processing system comprising:

18. The program measuring the impedance of the RF signal with the input sensor of the RF match after adjusting the match parameters within the RF match; further adjusting the matching parameters in the RF match based on the measured impedance of the RF signal to achieve a third match point; 20. The plasma processing system of claim 17, further comprising instructions for performing:

19. 20. The plasma processing system of claim 17, wherein the instructions for calculating the composite impedance parameter include calculating a weighted average between the first set of impedance-related data and the second set of impedance-related data.

20. The program measuring a third set of impedance-related data of the plasma processing system over a third period of time with the output sensor of the RF match, the third period of time beginning after a third delay that begins simultaneously with the first delay; measuring a fourth set of impedance-related data of the plasma processing system over a fourth time period with the output sensor of the RF match, the fourth time period starting after a fourth delay that starts simultaneously with the first delay; calculating the composite impedance parameter by the RF matching based on the first set of measured impedance-related data, the second set of measured impedance-related data, the third set of measured impedance-related data, and the fourth set of measured impedance-related data; 20. The plasma processing system of claim 17, further comprising instructions for performing:

Images