Radio frequency system protection based on temperature inference

Abstract

A method for thermally protecting an electronic circuit is described. In at least one implementation, an electronic circuit includes at least a first component and a second component. In at least one implementation, a method includes measuring a first input voltage and a first input current of a first component. In at least one implementation, the method further includes calculating a second input voltage and a second input current for a second component. In at least one implementation, the method further includes calculating a first temperature of the first component and a second temperature of the second component, where the first temperature is a function of the first input current and the second temperature is a function of the second input current.

Description

Priority claim

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 365,992, filed on June 7, 2022, and entitled “RADIO FREQUENCY SYSTEMPROTECTION BASED ON TEMPERATURE INFERENCE,” the entire contents of which are incorporated by reference for all purposes. Background Art

[0002] Processing tools are used to perform processes such as deposition and etching of films on semiconductor wafer substrates. These processing tools can use plasma for etching, substrate cleaning and deposition. Plasma can be generated and maintained by capacitive or inductive coupling to a field generated, controlled and distributed by a power transmission network outside the room. The power transmission network can transmit power from a radio frequency power generator to a coupling interface. The coupling interface can be an inductive coil, an antenna, or a capacitive electrode that couples RF energy stored in a magnetic field or an electric field to the plasma. Due to fluctuations in electron density and current in the coupled plasma, the impedance load of the power transmission network may fluctuate. Impedance mismatches between the plasma and the power transmission network including the impedance matching network may occur randomly or systematically due to process drift, resulting in coupling losses caused by power reflections at the coupling interface. Losses may result in lower power efficiency and variations in process performance. The power transmission network may include multiple components in series and parallel combinations. The power transmission network components may include passive LC filters, transmission lines, and the like. The reflected power caused by the large impedance mismatch at the interface may cause excess current to flow through one or more components in the power transmission network, resulting in excessive heating of the components. Some components may be damaged due to excessive heating. Current solutions for the protection of sensitive power transmission network components include installing multiple temperature sensors along the power transmission network component chain to monitor the temperature of single or grouped heat-sensitive components. The remedy for excess current consumption may be to mark the condition and automatically or manually limit the power of the plasma. Other remedies may include setting an upper limit on the maximum power available to the plasma tool. These solutions involving multiple temperature sensors may be expensive and difficult to implement. In addition, the reduction of plasma power may unnecessarily limit the peak power that can be delivered to the plasma. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The materials described herein are provided as examples only and are not intended to limit the drawings in any way. For simplicity and clarity of description, the elements shown in the drawings are not necessarily drawn to scale and in exact locations. For example, for clarity, the size of some elements is magnified compared to the size of other elements. In addition, for clarity of discussion, various physical features may be presented in their simplified "ideal" form and geometric features, but it should not be understood that the actual situation may only be close to the ideal type shown. For example, smooth surfaces and square intersections may be drawn without considering the limited roughness, rounded corners, and non-ideal corner intersections of the structure formed by nanofabrication technology. In addition, where deemed appropriate, reference numerals are repeated in the drawings to indicate corresponding or similar elements.

[0004] Figure 1 A cross-sectional view of a plasma processing tool is depicted in accordance with at least one implementation.

[0005] Figure 2 A portion of a power transmission network showing cascaded components and conditions at nodes between the components including a transforming sequence of measured and calculated voltages and currents at each node is depicted according to at least one implementation.

[0006] Figure 3 A method for obtaining thermal constants of electrical components in a power transmission network is described in accordance with at least one implementation.

[0007] Figure 4 A method of determining temperatures of a plurality of cascaded components in a power transmission network is described in accordance with at least one implementation.

[0008] Figure 5 Depicted are graphs showing calculated and measured temperatures of exemplary components in a power delivery network versus time, according to at least one implementation.

[0009] Figure 6 A processor system having a machine-readable storage medium according to at least one implementation is described. Specific implementation plan

[0010] According to at least one implementation, an apparatus and method for protecting plasma power delivery network components from overheating and possible failure is disclosed herein. Such component overheating may occur when there is a mismatch between the instantaneous plasma impedance and the tuned impedance matching between the components of the plasma power delivery network. A large impedance mismatch may cause a large amount of power to be reflected from a plasma coupling interface such as a coil back to the power delivery network via an impedance matching network. The reflected power may cause impedance mismatches between components and may cause excess current to flow through one or more components. Some components may contain single or multiple temperature-sensitive circuit elements, which may overheat due to the excess current. The temperatures reached may exceed the thermal limits of the circuit elements given by the manufacturer. As a result, the circuit elements may be damaged or destroyed due to the large amount of heat input, which may cause the power delivery network to fail.

[0011] According to at least one implementation, the disclosed method provides, among other advantages, improvements to existing methods of protecting power delivery components in plasma processing systems. According to at least one implementation, the disclosed method employs single point measurements of RF voltage and current along the power delivery network. According to at least one implementation, among other advantages, advantages provided include reducing or removing temperature sensors conventionally used to monitor the temperature of plasma circuit components. Such temperature sensors are often difficult to install and, when used, can increase the operational complexity of a plasma processing tool. Furthermore, the addition of temperature sensors can increase the purchase and maintenance costs of a plasma processing tool.

[0012] In at least one implementation, the voltage and current may be actually measured at a single convenient node between any two components of the cascaded components along the power delivery network. In at least one implementation, the measured RF voltage and current may include the RF voltage across the input port of the first component on the downstream side of the node, and the RF current flowing into the input port of the first component. In at least one implementation, the measured RF voltage and current may be equivalent to the voltage across the output port of the second or upstream component, and the current flowing out of the output port of the upstream component.

[0013] In at least one implementation, once the RF current and voltage are measured, the RF current and voltage may be transformed into currents and voltages at other nodes along a chain of power delivery network components through the application of transfer functions and / or transfer matrices. In at least one implementation, by monitoring the voltage and current at a single node in the power delivery network, the current and voltage at multiple nodes in the power delivery network may be calculated simultaneously. In at least one implementation, the current flowing into each component and / or the node voltage across the input of a single component may be known within an acceptable error margin. In at least one implementation, once determined, the calculated current and / or voltage may be converted into input power to each component. In at least one implementation, a portion of the input power may be dissipated as heat via circuit element resistance and dielectric losses.

[0014] In at least one implementation, circuit elements within a single component may have predetermined thermal constants. In at least one implementation, after determination of currents and voltages at multiple nodes within the power delivery network, the calculated input power may be applied to thermal calculations customized for each circuit element within the component. An instantaneous estimated temperature of each circuit element may be determined. In at least one implementation, a single voltage and current sensor may be periodically read by a microprocessor to update the state of the measured node. In at least one implementation, the aforementioned series of calculations may be repeated to periodically update the temperature state of one or more components.

[0015] Thus, when a significant impedance mismatch condition occurs, according to at least one implementation, the disclosed method can provide a calculated temperature for each circuit element within each component within a power delivery network without the use of a temperature sensor. In at least one implementation, any significant temperature rise of a component or individual circuit elements within a component can be detected. In at least one implementation, an alarm is set for a user of a plasma chamber tool to mitigate the excessive temperature. In at least one implementation, a correction procedure is triggered to cause a reduction in the excessive temperature. In at least one implementation, RF energy can be delivered to the plasma in a pulse train. Such a pulse train can have a duty cycle, wherein the on time and off time can be adjusted during the duty cycle. In at least one implementation, by reducing the on time of the duty cycle, the average power delivered to the plasma can be reduced without reducing the voltage or current amplitude of the power waveform.

[0016] In at least one implementation, the calculated temperature may indicate a thermal overrun (or overtemperature) condition for a particular circuit element. To remedy the overtemperature condition, in at least one implementation, the peak RF power and the RMS (root mean square) power from the RF source may be maintained constant while the average power delivered to the plasma is reduced. In at least one implementation, the voltage and current at a single node along the power delivery network follow the duty cycle adjustment of the RF current. In at least one implementation, a global reduction in the current time phase in the duty cycle may allow the temperature of all circuit elements to decrease while keeping the peak levels of current and voltage substantially constant, thereby protecting the most thermally vulnerable components. In at least one implementation, the duty cycle may be adjusted again after the impedance mismatch condition is corrected or reduced.

[0017] In some cases, in order to avoid confusion in the disclosure of the present case, known methods and devices are shown in the form of block diagrams rather than in detail. The "implementation" or "an implementation" or "some implementations" referred to in various places in this specification means that the specific features, structures, functions, or characteristics described in combination with the implementation are included in at least one implementation in the disclosure. Therefore, the phrases "in an implementation" or "in an implementation" or "some implementations" appearing in various places throughout this specification do not necessarily refer to the same implementation in the disclosure. In addition, in one or more implementations, specific features, structures, functions or characteristics can be combined in any suitable manner. For example, the first implementation can be combined with the second implementation, as long as any specific features, structures, functions or characteristics associated with the two implementations are not mutually exclusive.

[0018] In this article, "coupling" and "connection" together with their derivatives can be used to describe the functional or structural relationship between components. These terms are not intended to be synonyms for each other. Relatively speaking, in a specific implementation, "connection" can be used to refer to two or more elements directly physically, optically or electrically contacting each other. In this article, "coupling" can be used to refer to two or more elements directly or indirectly (with other intermediate elements between) physically, electrically or magnetically contacting each other, and / or two or more elements cooperating or acting on each other (for example, in a causal relationship). In this article, "coupling" can also generally refer to the direct attachment of an electronic component to another electronic component. An electric field or a magnetic field can couple a component to another component, wherein a field is controlled by affecting other components in a certain way by a component.

[0019] As used herein, the terms "over," "below," "between," and "on" may generally refer to the relative position of one component or material with respect to other components or materials, where such physical relationship is of note. Unless these terms are modified by "directly" or "directly," one or more intervening components or materials may be present. Similar distinctions will apply in the case of assemblies of components. As used throughout the specification and claims, a list of items linked with "at least one" or "one or more" may mean any combination of the listed terms.

[0020] As used herein, "adjacent" generally refers to a position where one thing is immediately adjacent to (eg, next to or close to, with one or more things between them) or next to (eg, adjacent to) another thing.

[0021] Unless otherwise expressly specified when used, "substantially equal", "about equal" and "approximately equal" generally mean that there is no accidental variation between the two things described. In at least one implementation, such variation generally does not exceed + / -10% of the reference value.

[0022] As used herein, a "processing tool" may generally refer to a semiconductor processing tool such as a plasma processing tool, which may include a chamber equipped with an antenna coil coupled to a radio frequency (RF) signal source. In at least one implementation, the antenna coil is used to generate an electromagnetic field, which in turn generates an inductive electric field that sustains a plasma via a transformer.

[0023] As used herein, "upstream" and "downstream" may generally refer to the primary direction of power flow, mostly in terms of current flow. In at least one implementation, an upstream component is on the source, or generator, side of a node, and a downstream component is on the load side of a node, where power flows from the source to the load.

[0024] As used herein, a "node" may generally refer to a point between an output port of an upstream component and an input port of an adjacent downstream component. In at least one implementation, the components of the power delivery network are themselves viewed as a two-port network including an input port and an output port. In at least one implementation, each port has two terminals. In at least one implementation, the two-port network may be or may include a passive LC filter or a single inductor, resistor, and capacitor. In addition to passive LC devices, in at least one implementation, the two-port network may include transmission lines, switches, RF chokes, and the like.

[0025] As used herein, a "terminal" may generally refer to the end of a conductor or electrical component, such as a wire, which may be a point for connection to other conductors or electrical components. In the context of a coil, in at least one implementation, a terminal is the end of a winding. With respect to a coil segment, in at least one implementation, a coil segment may include terminals at the beginning and end of the coil segment conductor.

[0026] Herein, "inductor" may generally refer to a passive electronic device that stores magnetic energy from the current flowing through it. In at least one implementation, an inductor may include a conductor (e.g., a metal wire) that can couple an electromagnetism to another nearby conductor, thereby inducing a voltage and current in the second conductor. In at least one implementation, a magnetic field may be generated by a current flowing in a first conductor according to Faraday's law of induction. A conductor has the property of inductance, and inductance is a function of the amount of current flowing in the conductor and the shape or geometry of the conductor. Although any conductor can be an inductor, some shapes produce stronger inductance than other shapes. A straight conductor may have a smaller inductance depending on its diameter and length. For example, due to the mutual superposition coupling of the magnetic field between each winding, a straight conductor may be wound into a coil so that the inductance is multiplied by the number of windings per unit length, thereby enhancing the overall magnetic field. According to Ampere's law, the magnetic field from each winding pair will produce a multiplication of the magnetic field generated by the straight conductor. In at least one implementation, the coil may be a planar coil, or a spiral coil, such as a solenoid or a conical spiral.

[0027] As used herein, "capacitor" may generally refer to a passive electronic device that stores charge and electrical energy in the form of an electric field. In at least one implementation, a capacitor generally has at least two conductive plates that are close to each other and separated by a dielectric material. In at least one implementation, the dielectric material may be air (or other gas) or a vacuum. In at least one implementation, the dielectric may generally be a solid or liquid material, such as a polymer, ceramic, or semi-liquid electrolyte. In at least one implementation, opposite charges may accumulate on adjacent plates to form an electric field that extends from plate to plate via the dielectric. In at least one implementation, the electric field may store electrical energy.

[0028] As used herein, "radio frequency," abbreviated RF, may generally refer to a portion of the electromagnetic spectrum having a frequency range between 10 kilohertz (kHz) to hundreds of gigahertz (GHz).

[0029] As used herein, "plasma" may generally refer to a gaseous formation containing charged particles, such as positively or negatively charged atomic or molecular ions and electrons. Plasma is considered the fourth state of matter.

[0030] As used herein, "inductively coupled plasma" (abbreviated as ICP) may generally refer to a plasma generated by a time-varying magnetic field emanating from a primary inductor or plasma antenna, typically in the form of a coil, that conducts RF current. In at least one implementation, a small concentration of ionized atoms or molecules and free electrons in a gas may be generated in the discharge. In at least one implementation, the slightly ionized gas may be considered a secondary inductor coupled to the plasma antenna, and the plasma antenna may be considered a primary inductor of a transformer, with the plasma being considered a secondary inductor of the transformer to which the primary inductor is coupled. In at least one implementation, the gas may pass through an electromagnetic field generated by an adjacent ICP antenna, where charges are accelerated by a time-varying electric field associated with a time-varying magnetic field (according to Faraday's law of induction and the Faraday-Maxwell equation). In at least one implementation, the accelerated electrons may collide with neutral atoms or molecules to produce more ions and secondary electrons, thereby increasing the plasma density of charged particles. In at least one implementation, the amount of particle acceleration and resulting collision velocity is proportional to the strength of the electric field, which in turn is proportional to the strength of the magnetic field. Ultimately, in at least one implementation, the magnetic field strength is proportional to the amount of current flowing within the ICP antenna.

[0031] As used herein, an "ICP antenna" may generally refer to an inductor through which an RF current may pass and through which RF power may be radiated to a limited range as a near-field static and propagating electromagnetic field. In at least one implementation, the RF current flows through the ICP antenna to generate an electromagnetic field that couples to a partially ionized gas or to a fully developed plasma. In at least one implementation, the former may be caused to develop into a plasma by the action of the electromagnetic field.

[0032] As used herein, "capacitively coupled plasma" (CCP) may generally refer to a plasma that is capacitively coupled to the electric field between two or more electrodes within a plasma chamber.

[0033] As used herein, a "transmission line" may generally refer to a cable comprising at least two conductors that are parallel and closely spaced. In at least one implementation, each conductor of a transmission line generally carries equal and opposite currents and voltages. The magnetic fields of the opposite currents cancel, thereby substantially reducing or eliminating the emission of electromagnetic radiation from the conductors. In at least one implementation, a transmission line may carry RF current and voltage from a source to a load, such as an antenna that does not radiate RF energy. A transmission line has a characteristic impedance.

[0034] As used herein, "dielectric material" may generally refer to non-conductive materials such as polymers, ceramics, glass, wood, and the like.

[0035] As used herein, "radio frequency (RF)" generally refers to frequencies substantially including frequencies between 10 kilohertz (kHz) and 1 megahertz (THz, or 1015 Electromagnetic radiation that oscillates in a frequency spectrum with frequencies between 100 Hz and 200 Hz. In at least one implementation, the upper limit of the radio frequency spectrum may only extend to a few hundred gigahertz (GHz). The term radio frequency is often abbreviated to "RF."

[0036] As used herein, an "RF signal source" may generally refer to an electronic device that can generate an electrical signal at a radio frequency. In at least one implementation, the RF signal source is capable of outputting a large RF current (e.g., 1 ampere effective value or greater) at a large voltage. In at least one implementation, the RF signal source of the ICP antenna is typically capable of outputting up to hundreds of amperes at up to hundreds of volts to produce a large amount of power.

[0037] As used herein, a "circuit element" may generally refer to an active or passive electronic device that may be part of an electronic circuit.

[0038] As used herein, a "passive component" may generally refer to an electronic component having an output response that cannot be controlled by an electronic signal, wherein the output response is related to an input signal such as a voltage and / or current. In at least one implementation, the passive component is a resistor, wherein the voltage drop across the resistor cannot be controlled by a separate electrical signal, but is a function of the current flowing therethrough. Other examples of passive components are capacitors and inductors. In at least one implementation, a passive component may be modeled as a two-port component. In at least one implementation, an active component is an electronic device such as a transistor, which includes at least a third port to which a control signal is applied to control the output of the device.

[0039] As used herein, a "component" may generally refer to a passive and / or active circuit element or combination of circuit elements that is part of a network.

[0040] As used herein, a "network" may generally refer to a plurality of circuit elements connected together to form an electronic circuit. In at least one implementation, a network generally has one or more ports.

[0041] As used herein, a "port" may generally refer to a terminal of a network where a signal may be introduced into or leave the network. In at least one implementation, a network generally has at least two ports, at least one port being an input port, and at least one second port being an output port.

[0042] In this article, "input" generally refers to a network port that allows signals to enter the network. Input signals can be input voltage and input current.

[0043] As used herein, "output" may generally refer to a network port that allows a signal to leave the network. In at least one implementation, the output signal may be an output voltage and an output current.

[0044] As used herein, "impedance" may generally refer to the resistance of a circuit element to alternating current, typically at audio and RF frequencies. In at least one implementation, impedance may be a general term for resistance. In at least one implementation, reactance is the impedance of a capacitor or inductor. In at least one implementation, reactance differs from resistance in that reactance is non-dissipative (no power is lost as heat). Impedance is defined as the ratio of voltage to current. Complex impedance is a combination of resistance and reactance, where reactance is an imaginary value and resistance is a real value. Complex impedance may be represented in polar coordinates as magnitude and phase angle, where the phase angle is the phase between voltage and current.

[0045] Herein, "input impedance" and "output impedance" may generally refer to the impedance of an input port and an output port, respectively. They are the ratio of input voltage to input current and the ratio of output voltage to output current, respectively.

[0046] As used herein, an "impedance matching network" may generally refer to an electronic network that matches an output impedance to an input impedance.

[0047] As used herein, "LC filter" may generally refer to an electronic network that includes a combination of passive inductors (L) and capacitors (C) to pass a specific frequency input to the filter circuit. In at least one implementation, the LC filter is a high-pass filter, a low-pass filter, a band-pass filter, and a notch filter. In at least one implementation, the LC filter may also be an impedance matching network.

[0048] As used herein, a "power delivery network" may generally refer to an electronic circuit comprising a plurality of electrical components that may be coupled together. In at least one implementation, the components are coupled together in a series (cascade) manner. In at least one implementation, the power delivery network may be designed to transfer RF power from a source to a load.

[0049] As used herein, "cascade" may generally refer to a combination of networks connected in series such that an output of a first network is an input of a second network coupled to the first network.

[0050] As used herein, a "processing tool" may generally refer to a piece of equipment used in semiconductor manufacturing, and may also be referred to as a "semiconductor processing tool" when referring to semiconductor processing. In at least one implementation, a processing tool may generally include a vacuum chamber in which processes such as plasma etching of a substrate or plasma enhanced material deposition are performed. In at least one implementation, other processes not related to plasma may also be performed in a processing tool.

[0051] Herein, a "chuck" may generally refer to a stage or platform to which a substrate (eg, a wafer) may be attached.

[0052] As used herein, a "substrate" may generally refer to a wafer comprising a semiconductor (e.g., silicon) or an insulator (e.g., aluminum nitride, silicon carbide, silicon nitride, aluminum oxide, float glass, borosilicate glass, etc.). In at least one implementation, the wafer may be a slice of a single crystalline semiconductor or insulator. In at least one implementation, the wafer may also comprise polycrystalline or amorphous (glass) material. In at least one implementation, the wafer may have a diameter that typically ranges between 100 mm and 500 mm, and a thickness that typically ranges between 100 microns and 1 mm.

[0053] As used herein, a "processing chamber" may generally refer to a vacuum chamber of a processing tool into which a substrate may be introduced for processing. In at least one implementation, the processing chamber may include a chuck for holding the substrate. In at least one implementation, the processing chamber is a plasma etching chamber.

[0054] As used herein, "magnetic field" may generally refer to the direction and strength lines of magnetic flux emanating from a magnetized or current-carrying material.

[0055] As used herein, a "plasma enhanced process" may generally refer to a semiconductor process, such as one in which a plasma is used to assist the process in some way. In at least one implementation, a plasma enhanced process is enhanced compared to a similar or identical process without the plasma. Examples are reactive ion etching and plasma enhanced chemical vapor deposition or plasma enhanced atomic layer deposition.

[0056] Herein, "reactive species" may generally refer to electrons, ions or neutral radicals formed in a plasma.

[0057] As used herein, "ions" may generally refer to charged atoms or molecules. In at least one implementation, ions may be gaseous atoms or molecules that lose or gain electrons in a plasma.

[0058] Herein, "machine-readable storage medium" generally refers to a memory storing binary code or data readable by a processor. In at least one implementation, the machine-readable storage medium may be a non-volatile solid-state storage medium, a volatile memory, a magnetic hard disk, an optical disk, etc.

[0059] Herein, "machine-readable instructions" may generally refer to binary codes stored on a machine-readable storage medium. When the machine-readable instructions are executed, the binary instructions may cause the processor to perform specific functions.

[0060] As used herein, a "transfer matrix" may generally refer to a system of interdependent linear equations in matrix form for calculating a first voltage and a first current at a first node from a second voltage and a second current at a second node. In at least one implementation, the second voltage and the second current may be measured or calculated. In at least one implementation, the matrix may generally be a 2×2 matrix; larger matrices such as a 3×3 matrix may be applied. In at least one implementation, a transfer matrix may be applied to convert a first voltage and a first current at a first node in an electronic circuit to a second voltage and a second current at a second node. In at least one implementation, impedances may be similarly transformed.

[0061] As used herein, a "transfer function" may generally refer to an equation that calculates an input voltage or current of a circuit or circuit element as an output voltage or current of the circuit or circuit element. The terms of the equation may include combinations of circuit element values. A transfer function may similarly be applied to calculate an output voltage and / or current from an input voltage and / or current.

[0062] Figure 1 A cross-sectional view of a plasma processing tool 100 is depicted according to at least one implementation. In at least one implementation, the plasma processing tool 100 includes a plasma chamber 102 for plasma enhanced processing of a wafer 104, a chuck 106, a plasma 108, an antenna 110, a wall 112, and a power delivery network 114.

[0063] In at least one implementation, the chuck 106 can support the wafer 104 and electrically stabilize the wafer 104 in the presence of the plasma 108. In at least one implementation, the chuck 106 can be grounded or biased. In at least one implementation, the bias can be a DC voltage, or a periodic voltage waveform applied to the chuck 106. In at least one implementation, the plasma 108 can be an inductively coupled plasma (ICP) generated and maintained within the plasma chamber 102 by a radio frequency (RF) electromagnetic field radiated by the ICP antenna 110. In at least one implementation, the radiated electromagnetic field is indicated by a downward arrow representing the RF magnetic field labeled H, and a horizontal arrow representing the RF electric field labeled "E". In at least one implementation, the RF E field can ionize gaseous atoms and molecules introduced into the plasma chamber 102, thereby generating gaseous ions and free electrons. In at least one implementation, as shown, the free electrons can form a plasma current that follows a trajectory perpendicular to the RF H field. In at least one implementation, the plasma current can in turn generate an induced magnetic field B that couples back to the ICP antenna 110. In at least one implementation, the plasma 108 is electromagnetically coupled to the ICP antenna 110. In at least one implementation, the plasma 108 can be a capacitively coupled plasma (CCP) in which an electrode (not shown) within the plasma chamber 102 is coupled to the plasma 108, for example, by an RF electric field extending between the electrode and the chuck 106.

[0064] In at least one implementation, the ICP antenna 110 may be isolated from the plasma chamber 102 by a wall 112 to protect the ICP antenna 110 and any associated electronics from the plasma 108. The ICP antenna 110 may be fed by an RF power distribution network 114. In at least one implementation, the power delivery network 114 may include a plurality of N components, where N ≥ 1, represented here by components 116, 118, 120, and 122. In at least one implementation, components 116 to 122 may represent a portion of the RF power delivery network 114. In at least one implementation, N may be four or more. Component 116 is labeled component 1 and may be considered the first component in a chain of components of the RF power distribution network 114. In at least one implementation, a portion of the RF power delivery network 114 may be considered a source. In at least one implementation, the next component in the chain of components (component 118) is labeled component N-2. If N>4, then N-2>2, and one or more components may be included between component 116 and component 118. In at least one implementation, the remaining components 120 and 122 are labeled as component N-1 and component N, respectively, where component N is the final component in the chain of components. In at least one implementation, while components 116 to 122 (and more components not shown) are shown as coupled in series, some components may also be coupled in parallel.

[0065] In at least one implementation, components 116, 118, 120, and 122 are represented as cascaded two-port networks, each having an input port and an output port. In at least one implementation, in the configuration of the RF power delivery network 114, component 116 is upstream of components 118 to 122 from the perspective of power flow within the RF power delivery network 114. Reiterating the definitions given above, "upstream" here means "towards the source" and "downstream" means "towards the load". In at least one implementation, power flows from the source to the load. Here, according to at least one implementation, the source can be RF source 126 and / or RF source 128, and the load is the ICP antenna 110.

[0066] In at least one implementation, an output port of an upstream component may be coupled to an input port of an adjacent downstream component. According to at least one implementation, an output port 130 of component 118 may be coupled to an input port 132 of component 120, wherein component 120 is downstream of component 118. The coupling between the output port and the input port may be referred to as a node. In at least one implementation, a node may be defined by an input port of an upstream component and an output port of an adjacent downstream component. A node may be characterized by a node voltage and a node current. In at least one implementation, the node voltage may be the output voltage V of the upstream component measured across the two terminals. out In at least one implementation, the node current may be the output current I of the upstream component. out , the output current I out As I in Flows into the input port of a downstream component.

[0067] In at least one implementation, if V in / I in The ratio of the input impedance of each input port Z in and is defined as V for each output port out / I out The output impedance Z out Match, then V out =V in And I out =I in In at least one implementation, for impedance mismatch, V across the node out With V in may be different, but I out with I in In at least one implementation, reflected voltage and current waves resulting from impedance mismatch may result in a lack of continuity of voltage and current across the unmatched node.

[0068] In at least one implementation, individual components 116-122 may include passive circuits having circuit elements such as inductors (L), capacitors (C), resistors (R), and switches. In at least one implementation, at least some of the components 116-122 may include LCR (inductor, capacitor, and resistor) circuit elements that may be combined in a filter circuit in which a low-pass, high-pass, band-pass, or notch filter may be constructed. In at least one implementation, one or more components 116-122 may include an impedance matching network having an LC circuit configured as an "L" network topology, a "T" network topology, a "π (Pi)" network topology, or a combination thereof.

[0069] In at least one implementation, components 116 to 122 may also include passive circuit elements, such as, but not limited to, switches, transmission lines, transformers, directional couplers, power dividers, power combiners, single inductors (e.g., RF chokes), and capacitors. In at least one implementation, these components may be used, for example, for decoupling and blocking of LF (low frequency) and HF (high frequency) currents. The transmission line (e.g., transmission line 124) may be a coaxial transmission line or a two-conductor open wire line. In at least one implementation, the transmission line may couple component 122 at the load end of the RF power transmission network 114 to the ICP antenna 110. In at least one implementation, component 122 itself may be a transmission line, wherein transmission line 124 is coupled to the ICP antenna 110 as an extension of component 122.

[0070] In at least one implementation, the ICP antenna 110 may be coupled to RF signal sources 126 and 128 at an input port 134 upstream of the component 116, or a generator at the end of the component chain. In at least one implementation, the RF signal source 126 is a low frequency (LF) RF signal source or generator, and the RF signal source 128 is a high frequency (HF) signal generator. In at least one implementation, the RF signal source 126 may generate frequencies below 1 MHz, and the RF signal source 128 may generate frequencies above 1 MHz. The RF signal sources 126 and 128 may output pure sine wave voltages or other voltage waveforms, such as square waves, sawtooth waves, triangle waves, and other suitable waveforms. In at least one implementation, the RF signal sources 126 and 128 may have high power generation capabilities, for example, outputting up to 10 kilowatts of power (hundreds of volts and tens of amperes).

[0071] In at least one implementation, although the RF signal source 126 is shown as differentially coupled to the power delivery network 114, it may alternatively be coupled via a single-ended connection, where one terminal is grounded. In at least one implementation, this configuration is indicated by a dashed line connecting a ground symbol to the underside of the RF source 126. In at least one implementation, although the RF signal source 128 is shown as differentially coupled to the RF power delivery network 114, it may also be coupled to the RF power delivery network 114 in a single-ended manner. In at least one implementation, two RF signal sources are shown coupled to the RF power delivery network 114. In some implementations, a single RF signal source may be used. In at least one implementation, multiple (e.g., more than two) RF signal sources may be used.

[0072] In at least one implementation, the ICP antenna 110 is in the form of a coil. As mentioned above, the ICP antenna 110 can be isolated from the plasma chamber 102 by a wall 112. In at least one implementation, the wall 112 includes a dielectric material to allow the electric and magnetic fields from the ICP antenna 110 to couple with the plasma 108 within the plasma chamber 102. In at least one implementation, although the ICP antenna 110 is shown as a flat, or "pancake-shaped" coil, the ICP antenna 110 can have other suitable shapes, such as a serpentine coil or a helical solenoid coil. A single winding of the antenna coil is shown in the cross-section. As shown in the cross-section, the ICP antenna 110 is shown in the depicted implementation as a planar helical coil (e.g., a "pancake-shaped coil") containing multiple windings. In at least one implementation, for a tubular chamber geometry, the ICP antenna 110 can also have a helical (e.g., solenoid) geometry. In at least one implementation, the solenoid can have a generally cylindrical form factor, wherein the conductor can be in the form of a helical coil.

[0073] In at least one embodiment, as mentioned above, the plasma 108 is coupled to the ICP antenna 110 via the RF electromagnetic field emitted by the ICP antenna 110. In at least one embodiment, the electromagnetic field maintains the plasma 108. In at least one embodiment, the electric field E can be large enough to ionize the low-pressure gas introduced into the plasma chamber 102, usually by evacuating the plasma chamber 102 to a high vacuum. In at least one embodiment, the free electrons formed by the electric field can form a toroidal plasma current under the influence of the magnetic field H extending from the ICP antenna 110. In at least one embodiment, the free electron density n in the plasma 108 is e is at least in part a function of the supplied RF power, which can manifest as electric field strength E and magnetic field strength H, respectively. In at least one implementation, the RF frequency can also affect the free electron density n eIn at least one implementation, higher frequencies can increase the rate at which free electrons are formed by increasing the number of collisions between ions and gaseous atoms or molecules, and between electrons and gaseous atoms.

[0074] In at least one implementation, the free electron density n in the plasma 108 is e It can be a parameter that determines the plasma impedance. In at least one implementation, the plasma impedance can be represented as an electrical impedance Z comprising a series combination of a resistor and an inductor. p In at least one embodiment, the plasma impedance Z p In at least one implementation, the inductance of the plasma can be related to the ring plasma current i (also related to n) coupled back to the ICP antenna 110. e In at least one implementation, the interaction between the ICP antenna 110 and the plasma 108 is similar to the interaction between the primary winding and the secondary winding of a transformer.

[0075] In at least one implementation, the coupling between the plasma 108 and the ICP antenna 110 may affect the input impedance Z of the ICP antenna 110. ant In at least one implementation, it may be necessary to use an impedance matching network to make Z ant The components upstream of the ICP antenna 110 to the RF signal sources 126 and 128 within the RF power delivery network 114 are matched. In at least one implementation, the RF signal sources 126 and 128 may both have an output impedance Z of, for example, 50 ohms. gen In at least one implementation, the system impedance of the RF power delivery network can be designed to be 50 ohms, meaning that the Z of each component is 50 ohms when matched. in and Z out The Z of the ICP antenna 110 is also substantially 50 ohms. ant Can differ significantly from 50 Ohms.

[0076] In at least one implementation, the matching network can ant In at least one implementation, component 122 (e.g., component N) at the load end of RF power delivery network 114 may include, for example, an LC impedance matching L or Pi network to provide appropriate matching. In at least one implementation, component 122 may be a device specifically designed to convert Z ant In at least one implementation, the transmission line may have a Z ant The characteristic impedance Z0 is between 50 ohms and 100 ohms. In at least one implementation, the length of the transmission line (including the transmission line 124) can be adjusted to make Z antis matched to the system impedance (e.g., 50 ohms). In at least one implementation, if Z0 is approximately equal to Z ant With the geometric mean of the system impedance, the transmission line length can be reduced to one quarter of the wavelength at HF ​​frequencies (ie, Q cross section).

[0077] In at least one implementation, Z ant The fluctuation of Z can be partly attributed to the plasma impedance Z during the process. p Fluctuations in Z, for example, due to transient changes in gas flow rate or pressure in the plasma chamber 102. In at least one implementation, Z p The fluctuation of Z may cause the detuning of the matching network of component 122, thereby causing the input impedance of component 122 (e.g., Z Nin ) changes. In at least one implementation, the Z due to the detuning of component 122 Nin The change may result in the output impedance Z of component 120 (component N-1) N-1out In at least one implementation, a mismatch with the output impedance may cause an impedance mismatch at each node in the chain of components of the RF power delivery network 114 to propagate upward to the RF signal sources 126 and 128.

[0078] In at least one implementation, the matching network (eg, component 122) may include variable capacitors and / or inductors as circuit elements to enable tuning of the matching network to follow the voltage at which Z p The fluctuation of Z ant In at least one implementation, the matching network (e.g., component 122) can be tuned to accommodate a small range of plasma impedances. In at least one implementation, the tuning can be performed in part by including a variable capacitor or inductor also in the upstream component to adjust the output and input impedance Z between adjacent components. in and Z out Matching. In at least one implementation, the value of the LC filter circuit elements within a component can be adjusted to produce the desired matching impedance to match these adjacent upstream and downstream components. This approach can be cumbersome because controls may be required for each component to drive the variable capacitor or inductor.

[0079] Assume that the specified Z ant Adjust the output impedance of component 122, then the output impedance Z of component 120 is N-1out The input impedance Z of the component 122 is seen NinThe change can be made in such a way that the component 120 can draw more current. In addition, the power reaching the plasma 108 can be reduced by the current and voltage reflection occurring at the output port 136 of the component 122. The amount of power reflected back to the input port 138 of the component 122 can be represented by the reflection coefficient p for the current and voltage reflected from the node 142 between the component 122 and the transmission line 124. The reflected RF current and voltage waves can produce standing waves along the transmission line 124 and partially within the component 122. For a large standing wave ratio (SWR), the current standing wave can contain current peaks that are much larger than the rated values ​​of the circuit elements within the component 122. Some circuit elements may not be able to safely carry such high currents. If the circuit element is subjected to a current that exceeds the manufacturer's circuit element rating, overheating may occur. Overheating of a single circuit element may cause failure of the entire component. In some cases, the coupling of the power source (e.g., RF signal source 126 and / or 128) to the ICP antenna 110 may gradually become detuned over time. This gradual detuning may result in a more gradual impedance mismatch between the RF signal source and the plasma 108. The impedance mismatch may gradually increase over time.

[0080] Although the above description has focused on an inductively coupled plasma system, in at least one implementation, a capacitively coupled plasma (CCP) system may be applied to the plasma processing tool 100. In at least one implementation, in a CCP system, the plasma chamber 102 includes a pair of electrodes separated by a distance. In at least one implementation, one of the pair of electrodes may be a CCP electrode. In at least one implementation, the CCP electrode may be a metal object within the plasma chamber 102, wherein the CCP electrode is in direct contact with the plasma (e.g., plasma 108). In at least one implementation, the second of the pair of electrodes may be, for example, a chuck 106. In at least one implementation, the plasma may be generated between the CCP electrode and the chuck 106. In at least one implementation, as shown, the wafer 104 rests on the chuck 106. In at least one implementation, the chuck 106 may be grounded or biased in the CCP system. In at least one implementation, the bias may be DC or RF. In at least one implementation, the RF source 126 can provide a low frequency RF bias to the chuck 106 if coupled to a low pass filter. The RF signal source 128 can provide a primary high frequency RF coupled to the plasma 108. In at least one implementation, the electrode is positioned at a gas distribution manifold (e.g., a heated showerhead) above the wafer 104 supported on the chuck 106. In at least one implementation, the frequency difference between the RF signal sources 126 and 128 can be significant, such as having a frequency difference of 10:1 or more.

[0081] In at least one implementation, during operation, a plasma 108 is formed above the wafer 104 and the chuck 106. The RF magnetic field penetrating the plasma chamber 102 can generate a plasma current that oscillates at the same frequency as the RF current flowing in the power delivery network 114. In at least one implementation, the RF current can have a peak amplitude of tens to hundreds of amperes. In at least one implementation, a sensor 140 for measuring voltage and current can be coupled to any suitable node within the RF power delivery network 114. In at least one implementation, the sensor 140 can be an RF current and / or voltage measurement sensor (e.g., a V, I sensor), a vector network sensor, an impedance sensor, etc. In at least one implementation, the sensor 140 can be a V, I sensor to measure both RF voltage and current, which is coupled to the RF power delivery network 114 at a node 142 between components 120 and 122 as shown. In at least one implementation, the sensor 140 can be coupled to a circuit that allows coupling to a processor 144. In at least one implementation, the sensor 140 can provide a digitized output stream to a processor 144, which can be read and analyzed by software code stored in a memory 146 coupled to the processor 144. In at least one implementation, the memory 146 can be a machine-readable storage medium, such as a non-volatile solid-state memory, a hard disk drive, an optical disk, and other suitable unit formats. In at least one implementation, the memory 146 can store a computer program containing machine-executable instructions. In at least one implementation, the processor 144 can be a portion of a control circuit for the plasma processing tool 100, which is local or remotely coupled via a network.

[0082] In at least one implementation, the processor 144 may execute software code including routines containing instructions to calculate the voltage and current at each node within the RF power delivery network 114 based solely on the voltage and / or current read at the single node 142. In at least one implementation, the software routines stored in the memory 146 may contain instructions according to the method implementation described in the present disclosure. In at least one implementation, the calculated current and / or voltage may be converted to power dissipated as heat within a single component (e.g., components 116 to 122). In at least one implementation, the derived power figures may be inserted into the heat equation contained in the software code stored in the memory 146 to determine the calculated temperature of the component or individual circuit elements within the individual component. In at least one implementation, for example, if the selected component or its circuit elements are identified as temperature sensitive, a sequence of calculations may be performed for the selected component or its circuit elements. In at least one implementation, as shown, the processor 144 is also coupled to the RF signal sources 126 and 128. In at least one implementation, processor 144 can communicate with RF signal sources 126 and 128 to control output power and / or duty cycle, for example, in response to a detected over-temperature condition. A more complete description of control instructions is provided below.

[0083] Figure 2 A graphical representation of a method for obtaining component temperatures within an RF power delivery network 200 including cascaded components according to at least one implementation is depicted. Voltage and current conditions at each node are depicted. Figure 2 , a portion of an RF power delivery network 200 including components 202, 204, and 206 is shown according to at least one implementation. Components 202, 204, and 206 are labeled as component N-1, component N, and component N+1, respectively. In at least one implementation, components 202 to 206 are part of a larger RF power delivery network 200, including a preceding portion and a succeeding portion. In at least one implementation, the preceding portion may include multiple upstream components (e.g., components labeled 1, 2, ... N-2). In at least one implementation, the succeeding portion may include multiple downstream components (e.g., components labeled N+2, N+3, etc.).

[0084] In at least one implementation, adjacent upstream and downstream components are coupled via nodes. In at least one implementation, node 210 couples component 202 to component 204, and node 212 couples component 204 to component 206. In at least one implementation, nodes 208 and 214 are terminal nodes. In at least one implementation, although terminal nodes 208 and 214 appear as open ends in the figure, it is understood that node 208 is also coupled to an adjacent upstream component N-2, which is not shown, and node 214 is coupled to an adjacent downstream component N+2, which is also not shown in the figure.

[0085] In at least one implementation, a single component within RF power delivery network 200 can be represented as a two-port network, which includes an input port and an output port. In at least one implementation, component 202 includes input port 216 and output port 218. Individual nodes 208 to 214 are each defined by an output port of an upstream component and an input port of an adjacent downstream component. In at least one implementation, node 210 is defined by output port 218 of component 202 and input port 220 of component 204, and node 212 is defined by output port 222 of component 204 and input port 224 of component 206. In at least one implementation, the ports include two terminals. In at least one implementation, the input voltage V in and input current I in In at least one implementation, for each input port 216, 220, and 224, the input voltage is respectively represented by V N-1in 、V Nin and V N+1in In at least one implementation, the name follows the component position in the component chain, e.g. N-1in Corresponding to component N-1, etc. In at least one implementation, output ports 218, 222, and 226 may be similarly characterized by output voltage and current indications. In at least one implementation, nodes 208, 210, 212, and 214 may also be characterized by node voltages and currents. In at least one implementation, node voltages V N and current i N Node 210 is represented, where the subscript N refers to a downstream component (eg, component 204 ).

[0086] In at least one implementation, similarly, V N+1 and i N+1 etc. characterizes a node 212 between components N and N+1 (204 and 206, respectively). In at least one implementation, within a single node, if the output impedance Z of the upstream component is out The input impedance Z of the downstream components in (For example, Z out =V / i=Z in ) match, the upstream output voltage and current can be substantially equal to the downstream input voltage and current. In at least one implementation, if an impedance mismatch occurs downstream in the component chain of the RF power delivery network 200, the Z of the downstream component in Possibly relative to the Z of the upstream component out In at least one embodiment, if the plasma impedance Z pIf the impedance of the load terminal of the RF power transmission network 200 fluctuates and is no longer matched by the matching network, an impedance mismatch condition occurs at the load terminal of the RF power transmission network 200. In at least one implementation, the impedance mismatch may propagate upward in the component chain and cause impedance mismatch at each node in the component chain. In at least one implementation, when Z N-1out =Z Nin When V at the output port 218 of the component 202 N-1out and i N-1out is substantially equal to V at the input port 220 of the component 204 Nin and I Nin In at least one implementation, when Z N-1out ≠Z Nin When the output voltage and current and the input voltage and current are equal, the equations may no longer hold. In at least one implementation, reflections of voltage and current waves may occur at node boundaries.

[0087] In at least one implementation, because of the impedance mismatch condition, when looking at adjacent input ports 220 and 224, output ports 218 and 222 may see an unmatched Z. in In at least one implementation, this occurs in a chain of components where each component has a Z in will also vary according to its proximity to upstream components) and propagate upwards, at any RF signal source (e.g. Figure 1 126 and / or RF signal source 128 shown in FIG. 12 . In at least one implementation, power may also be reflected through each mismatched node, which may cause increased current consumption by some or all components in the RF power delivery network 200. In at least one implementation, the current consumed by some components may increase beyond the rated limit, which may cause overheating of individual circuit elements within the individual components. In at least one implementation, component 204 may include an LC filter circuit having a capacitor and an inductor. In at least one implementation, although normal current levels may cause heat dissipation of either or both circuit elements, excessive current may cause overheating of either or both circuit elements. In at least one implementation, the circuit elements may have a maximum rated temperature. If the maximum rated temperature is exceeded, the circuit elements may be damaged or destroyed.

[0088] In at least one implementation, by Figure 2 The diagram shows a method for obtaining the temperature of components 202, 204, and 206 to protect temperature sensitive components or circuit elements within some or all of the components. In at least one implementation, a single sensor 228 (e.g., such as a Figure 1The sensor 228 is coupled to any node within the RF power delivery network 200. In at least one implementation, the sensor 228 is coupled to the node 212 between components 204 and 206 (e.g., component N and component N+1). In at least one implementation, the sensor 228 can continuously measure the node voltage and the node current V N+1 with i N+1 In at least one implementation, once measured, V may be continuously read by processor 230. N+1 with i N+1 In at least one implementation, processor 230 may calculate V at other nodes (e.g., V at nodes 208, 210, and 214, respectively) by applying a transfer function and / or a mathematical transformation of a transfer matrix. N-1 、i N-1 、V N 、i N 、V N+2 、i N+2 ). In at least one implementation, the transfer matrix comprises, for example, a set of interdependent linear equations in matrix form for calculating a first voltage and a first current at a first node based on a second voltage and a second current at a second node. In at least one implementation, the second voltage and the second current may be measured or calculated.

[0089] In at least one implementation, the second voltage and the second current may be linearly combined by matrix coefficients. In at least one implementation, the matrix coefficients transform the second voltage and the second current into the first voltage and the first current. In at least one implementation, the matrix coefficients may be a transfer function for transforming the second voltage and the second current into the first voltage, and for transforming the second voltage and the second current into the first current. In at least one implementation, the transfer matrix may be encoded into machine-readable instructions that may be stored in a memory 232 coupled to the processor 230. In at least one implementation, the transfer matrix may be applied to transform the voltage and current measured at the node 212 into the voltage and current at the node 210. In at least one implementation, an exemplary transfer matrix for a two-port electrical network may have a form given by equation [1]: Where V1 may be the voltage across a first (e.g., input) port, and I1 may be the current flowing into the first port. V2 may be the voltage across a second (e.g., output) port, and I2 may be the current flowing out of the second port. In at least one implementation, the coefficients A, B, C, and D for individual components may be determined empirically. In at least one implementation, A = [V1 / V2] I2＝0 ; B = [-V1 / I2] V2＝0 ; C = [I1 / V2] V1＝0 ; D = [V2 / V1]I1＝0 In at least one implementation, in circuits that include resistive and / or reactive components, the values ​​of coefficients A, B, C, and D may be based on reactance and susceptance values ​​associated with individual circuit elements combined in a particular circuit topology within components 202, 204, and 206.

[0090] In at least one implementation, the transfer matrices may be cascaded to calculate voltages and currents at nodes upstream and downstream of node 212 along a chain of components of RF power delivery network 200 .

[0091] In at least one implementation, the node computation based on the cascaded transfer matrix may have the form given by equation [2]:

[0092] In at least one implementation, equation [2] may be encoded into software stored in memory 232 and solved numerically. In at least one implementation, coefficients A, B, C, and D may be predetermined for some or all of the components or for selected temperature sensitive circuit elements. In at least one implementation, processor 230 may read sensor 228 at predetermined time intervals. In at least one implementation, sensor 228 coupled to node 212 measures V N+1 with i N+1 In at least one implementation, the processor 230 may measure the voltage V at the node 208 by N+1 With current I N+1 The voltage V of node 210 is calculated by transforming N with I N In at least one implementation, once values ​​of the input voltage and current may be determined at other nodes 208 , 210 , and 214 .

[0093] In at least one implementation, once i is measured inN+1 And based on i inN+1 Calculate i inN with i inN-1 After that, for example, according to the calculated i inN-1 with i inN The power dissipation within the individual components 202, 204, and 206 is determined based on the value of . In at least one implementation, knowledge of the circuit topology and dielectric and series resistance losses of individual circuit elements such as capacitors and inductors may be invoked. In at least one implementation, based on the calculated node currents, the Joule heat (I 2 In this context, for example, knowledge of the series resistance and dielectric loss parameters of inductors and capacitors can be used.

[0094] In at least one implementation, due to I 2 A temperature change may occur within each component due to excess Joule heating due to R losses, where I may include excess input current to the component. R may represent series resistance or dielectric losses. In at least one implementation, the temperature rise within a single component may be determined by numerical calculations performed by processor 230. In at least one implementation, processor 230 may execute software instructions stored in memory 232 to, for example, calculate the quasi-instantaneous temperature as a numerical heat transfer differential equation. In at least one implementation, such a numerical heat transfer differential equation may have the form of equation [3]: T(t n )=k1(T0-T(t n-1 ))Δt+k2(I,V) 2 (t n )Δt [3] Where T(t n ), T0, k1 and k2, Δt are respectively n Component temperature at time, t n is the nth time increment, T0 is the reference temperature, and k1 and k2 are constants related to the energy gain and loss of the system. Δt is the time increment. In at least one implementation, the thermal constants k1 and k2 of individual components (e.g., components 202, 204, and 206) may be determined empirically. An exemplary procedure for determining the thermal constants k1 and k2 is described below. In at least one implementation, T(t N ) distribution. In at least one implementation, the software may include instructions for further determining whether the rated temperature of the component or circuit elements within the component has been exceeded at any point in the process. In at least one implementation, the last term of equation [3] is the Joule heating term, which is the numerical integration of the electrical power to calculate the temperature according to I 2 R or V 2 / R Calculates joules.

[0095] Figure 3A method 300 is depicted for obtaining thermal constants of electrical components in a power delivery network (e.g., power delivery network 114 or 200) according to at least one implementation. In at least one implementation, many of the blocks or operations may be performed by hardware, software, or a combination of both. The method 300 provides thermal protection for temperature sensitive components within a power delivery network according to at least one implementation. In at least one implementation, the method 300 may be performed by a digital processor executing machine-readable instructions in a computer program stored in a memory coupled to the processor according to certain implementations. In at least one implementation, the thermal characteristics of a component under test to be used in an RF power delivery network, such as an RF power delivery network, may be determined empirically. Figure 1 The RF power delivery network 114 shown in or Figure 2 . In at least one implementation, the component under test is subjected to actual power delivery conditions that can be foreseen in actual use of the power delivery network. In at least one implementation, the method describes operations that can be used to obtain thermal characteristics, such as thermal constants k1 and k2 of the component under test. In at least one implementation, the component under test can be an actual component used in the RF power delivery network.

[0096] In at least one implementation, at operation 301, an RF current may be generated by an RF signal source, such as RF signal source 126 or 128, wherein the RF signal source is coupled to the component under test. In at least one implementation, the RF current may flow through the component under test. In at least one implementation, the component under test may include a combination of passive circuit elements or may include a single circuit element. In at least one implementation, the circuit elements may include passive elements such as, but not limited to, capacitors, inductors, transformers, resistors, directional couplers, power dividers and combiners, switches, and transmission lines. In at least one implementation, the RF current may be selected to have an RMS value that heats the component by Joule heating, which is quantified as I 2 R heating. In at least one implementation, the quantity R can be the equivalent series resistance of the component and can be the cause of dissipative losses in the component. In at least one implementation, the current I can be an RMS RF current value that is substantially equivalent in value to the current generated by causing the same I in the component. 2 In at least one implementation, a 1 ampere peak amplitude of the sinusoidal RF current has an RMS value of about I = 0.7 amperes, which is about I 2Rheating is equivalent to I=0.7 amps DC. In at least one implementation, the RF current may be delivered in a burst of pulses managed with a duty cycle, where the RF current is periodically turned on and off, in contrast to continuous delivery of the RF current which may be controlled by adjusting its peak amplitude. In at least one implementation, for RF current controlled with a duty cycle, the relevant parameters may be the length of the duty cycle period and the percentage of on and off time within the duty cycle period.

[0097] In at least one implementation, the duty cycle period can be the sum of the on-time and off-time portions of the duty cycle. In at least one implementation, by managing the RF current as a controlled train or pulse, the average RF current delivered to the component under test can be adjusted by adjusting the on-time and off-time durations of the duty cycle. In at least one implementation, the temperature rise within the component under test can be proportional to the average RF current during the pulse, rather than proportional to the peak RF current. In at least one implementation, the peak RF current can be held constant, thereby enabling the peak power delivered to the plasma to be as high as necessary to maintain desired plasma properties (e.g., electron density n e ) required value. In at least one implementation, the on-time and off-time phases of the duty cycle can be measured in seconds. Both parameters can be optimized.

[0098] In at least one implementation, flowing the RF current in pulses can provide maximum peak power delivery to the plasma while limiting the amount of time the component is subjected to Joule heating. In at least one implementation, the peak power can be maintained, for example, to produce a desired electron density within the plasma. In at least one implementation, the component can support peak currents that significantly exceed manufacturer ratings for a short period of time. In at least one implementation, adjusting the on time of the duty cycle can allow temperature transients developed during the current pulses to ease, effectively allowing the component under test to cool between current pulses. In at least one implementation, during operation 301, the component is allowed to heat to an elevated temperature by flowing current for a set period of time.

[0099] In at least one implementation, at operations 302 and 303, the current is stopped and the component under test is allowed to cool. In at least one implementation, during the cooling phase, the falling temperature of the component under test may be recorded by a temperature sensor. In at least one implementation, a thermocouple, an infrared camera, a resistance temperature detector (RTD), a Peltier component, etc. may be used as a temperature probe to obtain accurate temperature measurements of the component. In at least one implementation, the falling temperature-time curve of the component under test may be unique to the following items: the specific geometry of the component under test, its local environment in terms of nearby objects (including the housing and any insulation around the component under test), its thermal resistance, and exposure to both natural or forced convection. In at least one implementation, the temperature may be measured by reading a temperature probe or a set of probes set at intervals. For example, a microprocessor may read the temperature probe at appropriate time intervals and store the readings in a memory buffer.

[0100] In at least one implementation, the set of recorded temperature data may be subjected to a fitting routine to determine thermal constants k1 and k2 at operation 304. In at least one implementation, a suitable method may be used, such as finite elements for two-dimensional and three-dimensional analysis, time increments in one-dimensional and two-dimensional analysis, etc. In at least one implementation, the set of recorded temperatures may be numerically fit to a heat transfer equation similar to equation [3].

[0101] In at least one implementation, the thermal constants k1 and k2 can be calculated for the component under test by numerically solving the heat transfer equation. Figure 1 The method 300 may be repeated for some or all components of the RF power delivery network 114 in the RF power delivery network. In at least one implementation, all components within a particular RF power delivery network may be evaluated by the method 300, or selected components that exhibit temperature sensitivity may be evaluated. In at least one implementation, once the values ​​of k1 and k2 are determined for the components of interest, they may be applied to the components based on the temperature sensitivity of the RF power delivery network. Figure 2 The equation [3] or the following Figure 4 Temperature calculation.

[0102] Figure 4 A method 400 for determining the temperature of a plurality of components in a power delivery network, such as a power delivery network, is depicted according to at least one implementation. Figure 1 The power delivery network 114 shown. In at least one implementation, the operations of method 400 may be performed by software, hardware, or a combination of both. In at least one implementation, method 400 protects temperature sensitive circuit elements and components from overheating. In at least one implementation, the Figure 3As shown and described above, the thermal characteristics of the components to be used in the power transmission network are determined empirically in advance. In at least one implementation, the method 400 can be used with Figure 2 In at least one implementation, method 400 depicts operations 401 to 404 that may be used to convert current and voltage measured at a single node in a power transmission network into voltage and current at some or all nodes in the power transmission network and calculate component temperature. In at least one implementation, the temperature calculation may be based on thermal constants k1 and k2 of a single component obtained by method 300 described previously.

[0103] In at least one implementation, at operation 401, an RF voltage and current at a single node in a power transmission network are measured by a sensor for measuring RF voltage and current, for example, by Figure 1 The sensor 140 shown is performed. In at least one implementation, the sensor can be, for example, Figure 2 RF current-voltage probe, vector network analyzer, impedance analyzer, etc. of the sensor 228 shown. In at least one implementation, the relevant data may include instantaneous RF voltage, RF current, and optionally the phase angle between the RF voltage and the RF current. In at least one implementation, the vector network analyzer or impedance analyzer can automatically measure all three parameters. In at least one implementation, the phase angle may be necessary for calculating the complex impedance of the input port and output port of the component. In at least one implementation, ultimately, the current and / or voltage at the measurement node will be converted into voltage, current, and optionally complex impedance at some or all nodes in the power transmission network.

[0104] In at least one implementation, the measurements can be performed sequentially by reading the sensors at programmed time intervals by a microprocessor, such as Figure 1 The processor 144 is shown. In at least one implementation, the microprocessor may execute software instructions stored in a memory coupled to the microprocessor, such as a memory device. Figure 1 Memory 146 is shown. In at least one implementation, instructions may be included in a software loop so that measurements can be performed at consistent time intervals. In at least one implementation, the read data may be stored in a buffer.

[0105] In at least one implementation, at operation 402, a sensor coupled to a single node in an RF power network may measure an input voltage and current of a downstream component coupled to the same node. In at least one implementation, the measured voltage, current, and optionally measured phase angle may be numerically transformed by a processor into voltages and currents at nodes upstream and downstream of the measurement node. In at least one implementation, the numerical transformation may be performed by a subroutine contained in software containing machine-readable instructions to calculate a single node (e.g., Figure 2 208, 210, 214) shown in FIG. 2. In at least one implementation, equation [2] contains a transfer matrix for a two-port network similar to that shown above. In at least one implementation, the matrix coefficients, such as coefficients A, B, C, and D described above, may be determined for individual components of the RF power delivery network by experience or knowledge. In at least one implementation, the voltages and currents at the upstream and downstream nodes are encapsulated in the calculated [V, I] vectors and may be equivalent to the input voltages and currents of the individual components associated therewith.

[0106] In at least one implementation, in operation 403, the input current and / or voltage of the first component (e.g., component N) calculated based on the transformation of the measurement data performed in operation 402 may be converted into power dissipation through Joule heating. In at least one implementation, the input current i of component N may be converted into power dissipation through Joule heating. Nin Insert involves i 2 Nin The Joule heat power loss can be obtained by calculating R. In at least one implementation, V 2 Nin / R and apply the input voltage V in the same way Nin In at least one implementation, the parameter R can be a total series resistance associated with the circuit elements in the component.

[0107] In at least one implementation, I can be used in equation [3] 2 The temperature of the first component can be determined by inserting the R data or only by the input current of the first component. In at least one implementation, the thermal constants k1 and k2 may have been previously determined by a previous execution of the method 300. Figure 4 , by numerically solving equation [3], in at least one implementation, the calculated time-dependent temperature T(t) may be compared to a maximum temperature limit to determine if the limit has been exceeded. In at least one implementation, the maximum temperature limit may be obtained from a manufacturer of one or more temperature-sensitive circuit elements within the component. In at least one implementation, if the limit is exceeded, the software may include instructions for making a user aware of the over-temperature condition by setting an alarm, remediating the over-temperature condition, and taking avoidance action to reduce the temperature of the component.

[0108] In at least one implementation, the avoidance action may be a reduction in the overall duty cycle period, and / or a reduction in the on-time portion of the duty cycle. Such action may allow the components to cool to a certain degree between current pulses, where transient temperatures may be mitigated to temperatures below the limit. In at least one implementation, manipulation of the duty cycle may allow the peak power to remain high, as may be required to maintain a desired / target plasma electron density (e.g., at least 10 10 / cm 3 n e ).

[0109] In at least one implementation, at operation 404, the process described in operation 403 may be repeated for a second component (e.g., component N-1) in the power delivery network. In at least one implementation, the calculated time-dependent temperature of the second component may be compared to a maximum temperature limit of one or more temperature-sensitive circuit elements of the second component. In at least one implementation, similar remedial measures may be taken for the second component as described in operation 403 for the over-temperature condition in the first component.

[0110] Although method 400 may describe the measurement, transformation, and temperature calculation and over-temperature condition remediation process for two components in a power delivery network, method 400 may be repeated according to at least one implementation to calculate the temperature of some or other additional components within the same power delivery network. Thus, an over-temperature condition that may occur in any component within the power distribution network may be avoided or quickly remedied.

[0111] Figure 5 Depicted is a graph 500 of measured and calculated temperatures versus time for an exemplary component used in a power distribution network, such as the power delivery network 114, in accordance with at least one implementation. In at least one implementation, the exemplary component may be a single passive circuit element, such as a capacitor, an inductor, a resistor, a transmission line, etc. In at least one implementation, the component may also be a combination of single passive elements, such as an LC filter or an impedance matching network. Graph 500 shows a comparison between a calculated temperature-time profile (curve 502) and a measured temperature-time profile (curve 504) exhibited over a time interval in accordance with at least one implementation. Curve 502 is a dashed line to distinguish it from curve 504, which is represented by a solid line. In at least one implementation, the calculated temperature-time profile is based on Figure 2 , Figure 3 and Figure 4 The method described.

[0112] Reference again Figure 5, an exemplary graph 500 shows that, according to at least one implementation, through application of the above-described method, a calculated temperature-time profile substantially tracks a measured temperature-time profile. In at least one implementation, the RF current level is also shown in graph 500 as a series of current pulse trains or pulses shown as pulse train 506. In at least one implementation, the current pulse duration can be based on an on-time period evenly spaced apart by a duty cycle period. In at least one implementation, the pulse duration can be managed by a substantially fixed duty cycle. In exemplary graph 500, according to at least one implementation, the current pulses include a large amplitude current pulse 508 followed by a lower amplitude current pulse 510. Graph 500 shows an initial rapid temperature rise in region 512, where the RF current is continuous. Region 514 follows region 512. In region 514, the on and off durations of the current pulse train 506 remain the same as in region 512. In at least one implementation, the current peaks have a lower amplitude, thereby allowing a plateau to form in both the measured and calculated temperature-time profiles. In at least one implementation, the duration of the pulse train (e.g., the width of current pulses 508 and 510) can be, for example, 10 to 20 seconds, which corresponds to the on-time phase of the duty cycle. In at least one implementation, in region 516, the amplitudes of current pulses 508 and 510 increase substantially to the levels in region 512. In at least one implementation, both the measured and calculated temperature-time curves respond by rising. In at least one implementation, in region 518, the current pulse train is stopped and the temperature decreases monotonically. The calculated curve 504 follows the measured curve 502 exactly.

[0113] Figure 6 A processor system 600 is depicted having a machine-readable storage medium containing machine-readable instructions, such as a microcontroller in a circuit board of a control unit of a plasma processing tool 100 (eg, Figure 1 The processor 144 or Figure 2 The processor 230 in the microcontroller executes the machine-readable instructions according to the method 400. In at least one implementation, the microcontroller can measure and report the voltage and / or current at the nodes in the RF power delivery network 114, which couples the RF signal sources 126 and 128 with the plasma chamber 102. In at least one implementation, the process can be stored in a machine-readable medium (e.g., 603) as computer-executable instructions. In at least one implementation, the machine-readable storage medium can be, for example, Figure 1 Memory 146 or Figure 2In at least one implementation, the processor system 600 includes a memory 601, a processor 602, a machine-readable storage medium 603 (also referred to as a tangible machine-readable medium), a communication interface 604 (e.g., a wireless or wired interface), and a network bus 605 coupled together as shown. In at least one implementation, the processor 602 may represent Figure 1 Processor 144 in.

[0114] In at least one implementation, processor 602 is a digital signal processor (DSP), an application specific integrated circuit (ASIC), a general purpose central processing unit (CPU), or low power logic that implements a simple finite state machine to perform the various processes described herein.

[0115] In at least one implementation, the various logic blocks of the processor system 600 are coupled together via a network bus 605. Any suitable communication protocol may be used to implement the network bus 605. In at least one implementation, the storage medium 603 includes instructions (also referred to as program software code / instructions) for measuring voltage and current, transforming the measured voltage and current, and calculating temperature as described above with reference to various implementations.

[0116] In at least one implementation, the machine-readable storage medium 603 is a device having a method for measuring an RF power delivery network (eg, Figure 1 In at least one implementation, the machine-readable medium 603 (e.g., Figure 1 The memory 146 in the memory 146 has machine-readable instructions, which when executed cause the processor 602 to perform methods with reference to various implementation schemes.

[0117] In at least one implementation, program software code / instructions associated with various implementations may be implemented as part of an operating system or a specific application, component, program, object, module, routine, or other sequence of instructions or organization of sequences of instructions and referred to as "program software code / instructions," "operating system program software code / instructions," "application software code / instructions," or simply "software" or firmware embedded in a processor. In at least one implementation, the program software code / instructions are executed by the processor system 600.

[0118] In at least one implementation, the machine-readable storage medium 603 is a computer-executable storage medium. In at least one implementation, program software codes / instructions associated with various implementations are stored in the computer-executable storage medium 603 and executed by the processor 602. Herein, the computer-executable storage medium 603 is a tangible machine-readable medium 603 that can be used to store program software codes / instructions and data that, when executed by a computing device, causes one or more processors (e.g., processor 602) to perform a process.

[0119] In at least one implementation, the tangible machine-readable medium 603 may include storage of executable software program code / instructions and data at various tangible locations, such as ROM, volatile RAM, non-volatile memory and / or cache and / or other tangible storage as referenced in the present application. In at least one implementation, a portion of the program software code / instructions and / or data may be stored in any of these storage and memory devices. In at least one implementation, the program software code / instructions may be obtained from other storages, such as via a centralized server or a peer network, etc., including the Internet. In at least one implementation, different portions of the software program code / instructions and data may be obtained at different times and in different communication sessions or the same communication session.

[0120] In at least one implementation, software program code / instructions associated with various implementations may be fully acquired prior to execution of the corresponding software program or application. In at least one implementation, alternatively, a portion of the software program code / instructions and data may be acquired dynamically, e.g., just in time for execution. In at least one implementation, alternatively, some combination of these ways of acquiring software program code / instructions and data may occur, e.g., for different applications, components, programs, objects, modules, routines, or other instruction sequences or organizations of instruction sequences. In at least one implementation, the data and instructions may not need to be completely on the tangible machine-readable medium 603 at a particular point in time.

[0121] In at least one implementation, the tangible machine-readable medium 603 includes, but is not limited to, recordable and non-recordable types of media, such as volatile and non-volatile memory devices, read-only memory (ROM), random access memory (RAM), flash memory, floppy disks and other removable disks, magnetic storage media, optical storage media (e.g., compact disk read-only memory (CDROM), digital compact disk (DVD), etc.), and the like. In at least one implementation, the software program code / instructions may be temporarily stored in a digital tangible communication link and implemented via such tangible communication link as an electronic, optical, acoustic, or other form of propagated signal, such as a carrier wave, infrared signal, digital signal, etc.

[0122] The following examples are provided to illustrate various implementations. Examples may be combined with other examples. Thus, various implementations may be combined with other implementations without changing the scope of the invention.

[0123] Example 1 is a method for measuring temperature, comprising: applying a radio frequency (RF) current to an RF power delivery network, wherein the RF power delivery network comprises at least a first component coupled to a second component, wherein the first component comprises a first node and the second component comprises a second node, wherein the second node interconnects the first component and the second component; measuring a first voltage and a first current at the first node; calculating a second voltage and a second current at the second node based on the measurement of the first voltage and the measurement of the first current, and calculating a first temperature of the first component and a second temperature of the second component, wherein the first temperature is a function of the first current and the second temperature is a function of the second current.

[0124] Example 2. is a method according to any example in the present document, in particular Example 1, wherein calculating the second voltage and the second current includes transforming the first voltage into the second voltage and transforming the first current into the second current based on a first transfer matrix.

[0125] Example 3 is a method according to any example herein, in particular Example 2, further comprising determining a third voltage and a third current, wherein the second voltage is transformed into the third voltage and the second current is transformed into the third current based on a second transfer matrix.

[0126] Example 4 is a method according to any example herein, particularly Example 2, further comprising: converting the first current into a first dissipated power of the first component; and converting the second current into a second dissipated power of the second component.

[0127] Example 5 is a method according to any example herein, particularly Example 4, wherein calculating the first temperature of the first component includes calculating a first integral of the first dissipated power over a time interval.

[0128] Example 6 is a method according to any example herein, particularly Example 5, wherein calculating the second temperature of the second component comprises: calculating a second integral of the second dissipated power over the time interval; and multiplying the second integral by a second thermal constant of the second component.

[0129] Example 7 is a method according to any example herein, particularly Example 6, further comprising comparing the first temperature to a first temperature limit of the first component and comparing the second temperature to a second temperature limit of the second component.

[0130] Example 8 is a method according to any example described herein, in particular Example 7, further comprising adjusting a duty cycle of the RF current coupled to the RF power delivery network when at least the first temperature exceeds the first temperature limit or at least the second temperature exceeds the second temperature limit.

[0131] Example 9 is a method according to any example herein, in particular Example 2, wherein measuring the first voltage and the first current includes measuring a phase angle between the first current and the first voltage.

[0132] Example 10 is a method according to any example herein, in particular Example 9, wherein a first output impedance of the first component is determined from the first voltage, the first current, and the phase angle between the first current and the first voltage.

[0133] Example 11 is a machine-readable storage medium comprising: a computer program for thermally protecting an electronic circuit, wherein the electronic circuit comprises at least a first component and a second component, wherein the computer program comprises machine-executable instructions that, when executed by one or more machines, cause the one or more machines to perform a method, the method comprising: measuring a first input voltage and a first input current of the first component; calculating a second input voltage and a second input current of the second component; and calculating a first temperature of the first component and a second temperature of the second component, wherein the first temperature is a function of the first input current and the second temperature is a function of the second input current.

[0134] Example 12 is a machine-readable storage medium according to any example herein, particularly Example 11, wherein the method further comprises comparing the first temperature to a first temperature limit and comparing the second temperature to a second temperature limit.

[0135] Example 13 is a machine-readable storage medium according to any example herein, particularly Example 12, wherein the method further comprises adjusting a duty cycle of the RF current when at least the first temperature exceeds the first temperature limit, or the second temperature exceeds the second temperature limit.

[0136] Example 14 is a system comprising: a plasma chamber comprising a plasma coupling interface; a radio frequency (RF) signal source coupled to the plasma coupling interface via an RF power delivery network, wherein the RF power delivery network comprises a plurality of components; a sensor coupled to a first component of the plurality of components, the sensor for measuring a first voltage across the first component and a first current flowing through the first component; and a processor coupled to the sensor and for determining a second voltage across the second component of the plurality of components and a second current flowing through the second component, and for determining a first temperature in the first component and a second temperature in the second component.

[0137] Example 15 is a system according to any of the examples herein, in particular Example 14, wherein the processor is configured to determine the second voltage and the second current based on the first voltage and the first current.

[0138] Example 16 is a system according to any example herein, in particular Example 15, wherein the processor is configured to determine the second voltage and the second current based on a transfer matrix.

[0139] Example 17 is a system according to any example herein, particularly Example 14, wherein the plasma coupling interface comprises an inductively coupled plasma (ICP) antenna, wherein the ICP antenna is used to inductively couple to the plasma within the plasma chamber.

[0140] Example 18 is a system according to any of the examples herein, particularly Example 14, wherein the plasma coupling interface is a capacitively coupled plasma (CCP) electrode, wherein the CCP electrode is used to capacitively couple to the plasma within the plasma chamber.

[0141] Example 19 is a system according to any example herein, particularly Example 18, wherein the CCP electrode is a gas distribution manifold, wherein the gas distribution manifold is used to capacitively couple to the plasma within the plasma chamber.

[0142] In addition to what is described herein, various modifications may be made to the disclosed implementations without departing from the scope thereof. Therefore, the description of the implementations herein should be interpreted as merely illustrative and not limiting the scope of the present disclosure. The scope of the present invention should be measured only by reference to the claims that follow.

Claims

1. A method for measuring temperature, comprising: applying a radio frequency (RF) current to an RF power delivery network, wherein the RF power delivery network comprises at least a first component coupled to a second component, wherein: The first component comprises a first node; The second component comprises a second node; and the second node interconnects the first component and the second component, The method further comprises: measuring a first voltage and a first current at the first node; calculating a second voltage and a second current at the second node based on the measurement of the first voltage and the measurement of the first current, and A first temperature of the first component and a second temperature of the second component are calculated, wherein the first temperature is a function of the first current and the second temperature is a function of the second current. 2 . The method of claim 1 , wherein calculating the second voltage and the second current comprises transforming the first voltage into the second voltage and transforming the first current into the second current based on a first transfer matrix. 3 . The method of claim 2 , further comprising determining a third voltage and a third current, wherein the second voltage is transformed into the third voltage and the second current is transformed into the third current based on a second transfer matrix.

4. The method according to claim 2, further comprising: converting the first current into a first dissipated power of the first component; and The second current is converted into a second dissipated power of the second component. The method of claim 4 , wherein calculating the first temperature of the first component comprises calculating a first integral of the first dissipated power over a time interval.

6. The method of claim 5, wherein calculating the second temperature of the second component comprises: calculating a second integral of the second dissipated power over the time interval; and The second integral is multiplied by a second thermal constant of the second component. 7 . The method of claim 6 , further comprising comparing the first temperature to a first temperature limit of the first component and comparing the second temperature to a second temperature limit of the second component.

8. The method of claim 7, further comprising adjusting a duty cycle of the RF current coupled to the RF power delivery network when at least the first temperature exceeds the first temperature limit or at least the second temperature exceeds the second temperature limit.

9. The method of claim 2, wherein measuring the first voltage and the first current comprises measuring a phase angle between the first current and the first voltage.

10. The method of claim 9, wherein a first output impedance of the first component is determined from the first voltage, the first current, and the phase angle between the first current and the first voltage.

11. A machine-readable storage medium comprising: A computer program for thermally protecting an electronic circuit, wherein the electronic circuit comprises at least a first component and a second component, wherein the computer program comprises machine executable instructions which, when executed by one or more machines, cause the one or more machines to perform a method comprising: measuring a first input voltage and a first input current of the first component; calculating a second input voltage and a second input current of the second component; as well as A first temperature of the first component and a second temperature of the second component are calculated, wherein the first temperature is a function of the first input current and the second temperature is a function of the second input current.

12. The machine-readable storage medium of claim 11, wherein the method further comprises comparing the first temperature to a first temperature limit and comparing the second temperature to a second temperature limit.

13. The machine-readable storage medium of claim 12, wherein the method further comprises adjusting a duty cycle of an RF current when at least the first temperature exceeds the first temperature limit, or the second temperature exceeds the second temperature limit.

14. A system comprising: a plasma chamber comprising a plasma coupling interface; a radio frequency (RF) signal source coupled to the plasma coupling interface via an RF power delivery network, wherein the RF power delivery network comprises a plurality of components; a sensor coupled to a first component of the plurality of components, the sensor configured to measure a first voltage across the first component and a first current flowing through the first component; as well as A processor is coupled to the sensor and configured to determine a second voltage across and a second current through a second component of the plurality of components and to determine a first temperature in the first component and a second temperature in the second component.

15. The system of claim 14, wherein the processor is configured to determine the second voltage and the second current based on the first voltage and the first current.

16. The system of claim 15, wherein the processor is configured to determine the second voltage and the second current based on a transfer matrix.

17. The system of claim 14, wherein the plasma coupling interface comprises an inductively coupled plasma (ICP) antenna, wherein the ICP antenna is used to inductively couple to plasma within the plasma chamber.

18. The system of claim 14, wherein the plasma coupling interface is a capacitively coupled plasma (CCP) electrode, wherein the CCP electrode is used to capacitively couple to a plasma within the plasma chamber.

19. The system of claim 18, wherein the CCP electrode is a gas distribution manifold, wherein the gas distribution manifold is used to capacitively couple to the plasma within the plasma chamber.

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