System and method for power generation using phase-linked solid state generator modules

Abstract

A plasma generation system and method includes connected solid state generator modules. The solid state generators can be connected to a shared reference clock to generate outputs, and / or can be combined using phase optimization techniques.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Non-Provisional Application No. 16 / 881,458, filed May 22, 2020, entitled “SYSTEM AND METHOD OF POWERGENERATION WITH PHASE LINKED SOLID-STATE GENERATOR MODULES”, and U.S. Non-Provisional Application No. 16 / 881,390, filed May 22, 2020, entitled “SYSTEM AND METHOD OF POWER GENERATION WITH PHASE LINKED SOLID-STATE GENERATOR MODULES”, and claims priority and benefit to U.S. Provisional Patent Application No. 62 / 855,136, filed May 31, 2019, entitled “PHASE LINKING OF MULTIPLE SOLID-STATE GENERATOR MODULES AND SMART PALLETS FOR PLASMAGENERATOR”, the contents of which are incorporated herein by reference as if fully set forth herein. Technical Field

[0003] This subject matter relates to semiconductor processing, and more specifically to systems and methods for generating RF or microwave power. Background Technology

[0004] Existing solid-state microwave power generators typically combine multiple medium-power sources to achieve the required total output power. Since the combined power is a vector sum of individual sources, amplitude and phase imbalances between channels lead to power losses. While amplitude differences are often corrected, phase shifts are not corrected in state-of-the-art solid-state generators. The market demand for higher power and efficiency units (e.g., CVD synthetic diamond growth) poses a serious threat to effectively reducing phase-dependent losses.

[0005] Power generation can be used in a wide range of applications, from drying to plasma generation during semiconductor processing. In conventional methods of generating plasma in processing chambers used for semiconductor wafer processing (such as lift-off, etching, deposition) or high-end industrial plasma processing (such as plasma-assisted physical vapor deposition or PAPCVD for coating industrial tools and hardware), a single entry using RF or microwave input is employed. This single entry results in the formation of a non-uniform plasma in terms of intensity and density. In some systems, nozzles are used to distribute the plasma to mitigate this drawback to some extent. However, nozzles cannot provide ideal plasma formation within the processing chamber or cavity. Some known systems in the semiconductor industry employ multiple different RF generators to manipulate the plasma using large-volume magnetic confinement. One disadvantage of this approach is that each RF generator has an oscillator and is set to its own phase, resulting in inefficiency, localized heating, and less resonant oscillation.

[0006] Furthermore, impedance tuning is typically accomplished by measuring the amount of reflected power at a given region and changing the signal frequency to maximize the amount of absorbed positive power. A drawback of this approach is that it takes time to scan the signal from its minimum to its maximum value and select the lowest reflected power. Therefore, this method cannot be effectively performed in real-time under dynamic conditions.

[0007] Furthermore, degradation of processing chambers (e.g., plasma tubes or processing cavities) remains a problem in plasma generation systems and processes. Due to repeated and / or continuous exposure to harsh plasma environments, the surface condition of plasma tubes, processing chambers, and / or processing cavities deteriorates due to the interaction between the surface and the plasma. Typically, this interaction or degradation occurs in the form of an etching process. This process is most prevalent when the surface material (e.g., which may be a metal or dielectric (such as quartz, sapphire, ceramic), or other dielectrics) is exposed to fluorinated plasma chemicals (such as NF3 or CF4, or chlorine-based chemicals). Summary of the Invention

[0008] In view of the foregoing needs, in at least one aspect, this subject matter relates to a system and method for generating a uniform plasma with improved throughput and better yield. In some cases, the subject matter links multiple RF / microwave modules together in phase before combining power within the processing chamber. Impedance is measured within the processing chamber to obtain performance characteristics of the processing chamber. The impedance of individual RF generators is determined, and by understanding the impedance of individual generators (as well as phase, amplitude, and frequency), the plasma within the processing chamber is manipulated and tuned to minimize reflected power and / or induce a uniform plasma within the chamber to improve process performance on semiconductor substrates. The measured impedance can also be relied upon to identify unknown process gases and monitor the lifetime of the processing chamber. The described system and method can also determine the optimal phase shift between combined power supplies to maximize output power and efficiency.

[0009] In at least one aspect, the present invention relates to a plasma generation system having a reference clock, multiple solid-state generator modules, and a processing chamber. The reference clock is configured to generate a reference signal. Each solid-state generator module is linked to an electronic switch, and each electronic switch is linked to the reference clock. Each solid-state generator module is configured to generate an output based on the reference signal from the reference clock. The processing chamber is configured to receive the outputs of at least two of the solid-state generator modules for combining the outputs of the solid-state generator modules therein.

[0010] In some embodiments, the plasma generation system includes an I / Q modulator configured to demodulate a signal at the processing chamber input into an I / Q signal. The plasma generation system may then be further configured to: determine the voltage standing wave ratio (VSWR) and reflection coefficient of the I / Q signal; calculate a first impedance of one of the solid-state generator modules based on the VSWR and reflection coefficient; and calculate a second impedance based on the first impedance to determine the combined output power of the solid-state generator modules within the processing chamber. In some embodiments, the plasma generation system is also configured to adjust the phase, amplitude, and frequency of at least one of the solid-state generator modules based on the second impedance.

[0011] A plasma generation system can be configured to monitor changes in the impedance of a processing chamber over time. In some embodiments, the plasma generation system is configured to determine the remaining lifetime of the processing chamber based on changes in its impedance over time. The plasma generation system can be configured to issue an alert based on the remaining lifetime of the processing chamber. The plasma generation system may include a database storing impedance values ​​for various gases, and the system can be configured to use the database to identify process gases within the processing chamber based on changes in its impedance over time.

[0012] In some embodiments, the solid-state generator modules are connected in a phase-locked loop (PLL) such that the outputs of the solid-state generator modules have a shared phase. In some cases, each solid-state generator module includes a PLL reference input connected to an electronic switch and a PLL reference output connected to the electronic switch and a synthesizer, the synthesizer being connected to a second electronic switch to pulse modulate the output of the solid-state generator module.

[0013] In at least one aspect, this subject matter relates to a method for generating electricity using a power generation system. Multiple outputs are generated using multiple solid-state generator modules. Phase optimization techniques are used in a combiner to combine the outputs from the solid-state generator modules from multiple channels to generate in-phase combined output power.

[0014] In some embodiments, the phase optimization technique includes determining a phase shift for at least one channel and phase-shifting at least one channel. In some cases, the multiple channels include three channels. The phase optimization technique may then include opening the channels. A first channel, a second channel, and a third channel are determined. A second channel is phase-shifted based on the sum of the first and third channels to create an optimized second channel. The third channel is phase-shifted based on the sum of the first channel and the optimized second channel. In some embodiments, the method includes at least one additional channel, and the phase optimization technique includes, for each additional channel, phase-shifting the additional channel based on the sum of all other channels (including any optimized channel) to create an optimized additional channel. In some cases, the steps of phase-shifting the second channel, phase-shifting the third channel, and phase-shifting the additional channel are repeated multiple times.

[0015] In some embodiments, the phase optimization technique includes using an algorithm to determine the phase shift of at least one channel, the algorithm including at least one of the following: a bisection method, a Goertzel-Reinsch algorithm, or a discrete Fourier transform. In some embodiments, the plurality of channels includes three channels, and the phase optimization technique includes: determining a first channel, a second channel, and a third channel; opening the first channel and the second channel; phase-shifting the second channel to match the output of the first channel; closing the second channel and opening the third channel; and phase-shifting the third channel to match the output of the first channel.

[0016] In some embodiments, the method includes at least one additional channel, and the phase optimization technique includes: for each additional channel, opening a first channel and the additional channel, closing all other channels, and phase-shifting the additional channel to match the output of the first channel.

[0017] In some embodiments, the method includes providing in-phase combined output power to the waveguide output. In some embodiments, the solid-state generator module is connected in a phase-locked loop (PLL) such that the outputs of the solid-state generator module have a shared phase.

[0018] In at least one aspect, the subject matter relates to a power generation system having a plurality of solid-state generator modules configured to generate multiple outputs and a combiner. The combiner is configured to combine the outputs from the solid-state generator modules from multiple channels using phase optimization techniques to generate in-phase combined output power. Attached Figure Description

[0019] To make it easier for those skilled in the art to understand how to create and use this system, please refer to the following figures.

[0020] Figure 1 This is a schematic block diagram of a plasma generation system based on the technology of this subject.

[0021] Figure 2 This is a functional block diagram of an exemplary phase-locked loop (PLL) circuit that can be included as part of a plasma generation system according to the present subject matter.

[0022] Figure 3A This is a block diagram of a circuit configuration of an exemplary RF generator according to the art of this subject.

[0023] Figure 3B-3C yes Figure 3A A block diagram of the circuit section.

[0024] Figure 4 This is a schematic block diagram of another plasma generation system based on the technology of this subject.

[0025] Figure 5 This is a schematic functional block diagram of an I / Q modulator circuit that is part of a system configured according to the technology of this subject.

[0026] Figure 6 An exemplary polar plot of the I / Q signal is shown.

[0027] Figure 7 It is a graph comparing the individual power and combined power of generators based on the technology of this subject.

[0028] Figure 8A This is an example Smith chart.

[0029] Figure 8B An exemplary Smith chart with contour lines added for use in systems and processes is shown in accordance with the techniques of this subject matter.

[0030] Figure 9 This is a schematic block diagram of an exemplary power generation system based on the technology of this subject.

[0031] Figure 10A This is a diagram illustrating a portion of the phase optimization method according to the technology of this subject.

[0032] Figure 10B This is a diagram illustrating another part of the phase optimization method according to the technology of this subject. Detailed Implementation

[0033] This subject matter overcomes many of the prior art problems associated with generator systems and methods. In short, this subject matter provides a system and method for combining power from multiple phase-locked RF or microwave power modules. The advantages and other features of the systems and methods disclosed herein will become more apparent to those skilled in the art from the following detailed description of certain preferred embodiments, taken in conjunction with the accompanying drawings illustrating representative embodiments of the invention. The same reference numerals are used herein to denote the same parts. Furthermore, terms indicating direction (such as “upper,” “lower,” “far,” and “near”) are used only to help describe the position of components relative to each other. For example, the “upper” surface of a component is intended only to describe a surface separate from the “lower” surface of the same component. No terms indicating direction are used to describe absolute directions (i.e., the “upper” portion must always be on top).

[0034] Now for reference Figure 1 A schematic block diagram of a plasma generation system with a phase-locked solid-state RF generator (or microwave generator) according to some exemplary embodiments is generally shown as 100. System 100 includes a main power and control module 102, which generates energy for outputs 120a, 120b in a processing chamber 122. The main power and control module 102 includes a plurality of solid-state generators 104a, 104b, which are sub-modules of the main power and control module 102. While the exemplary power and control module 102 includes two solid-state generators 104a, 104b, it should be understood that this is only for ease of explanation. In other cases, a plurality of additional solid-state generators 104c, 104d, 104e…104n (collectively referred to as 104) may be included in the control module 102 and may function in accordance with the teachings herein. For example, in some cases, the power and control module 102 may include 10 solid-state generators 104. The generators 104 are phase-linked and operate with a shared clock signal to induce phase-locked loop (PLL) operation, as will be discussed in more detail herein. Each solid-state generator 104 includes RF source modules 106a and 106b and RF load modules 108a and 108b. RF source modules 106a and 106b control the frequency, phase, and power of the individual solid-state generators 104a and 104b. RF load modules 108a and 108b measure the load impedance and effectively measure the phase and amplitude of the load impedance of each individual generator 104a and 104b.

[0035] Outputs 120a, 120b from each solid-state generator 104a, 104b provide generator power to corresponding inputs 112a, 112b, which couple RF or microwave energy 128a, 128b to the processing chamber 122 via waveguides 114a, 114b (or coaxial cable delivery assembly, etc.). The frequency, phase, and power of the RF or microwave energy 128a, 128b are a result of coupling the inputs 112a, 112b to the processing chamber via waveguides 114a, 114b. The processing chamber 122 can be a cavity, plasma tube, etc., forming a reaction chamber. Within the reaction chamber 122, the processing substrate 124 (or semiconductor wafer, etc.) is preheated to the processing temperature on a heated chuck 126. Gas inlet 130 delivers processing gas to the processing chamber 122 according to the specific plasma processing formulation.

[0036] Inputs 112a and 112b contain the frequency, phase, and power (f1, f2) of RF or microwave energy 128a and 128b. P1 and f2, P2). Therefore, RF load module 108a measures the load impedance between output 120a and input 112a (and effectively measures the phase and amplitude). Similarly, RF load module 108b measures the load impedance between output 120b and input 112b. Based on the measurements from the respective RF load modules 108a, 108b, RF source modules 104a, 104b can then manipulate RF or microwave energy 128a, 128b, changing the frequency, phase, and power to provide space performance management within the processing chamber 122. It should be understood that system 100 may also include processors, data, and other processing components necessary to perform the functions of system 100 described herein.

[0037] As described above, the generator 104 of system 100 is arranged in a PLL. Now refer to Figure 2 A functional block diagram of an exemplary PLL is typically shown as 200. Specifically, while various configurations of the PLL can be implemented in the systems disclosed in this subject matter, PLL 200 is an example of such a system. The exemplary PLL 200 uses an input signal V. i 202 and generate an output signal V with a relevant phase. o 210. PLL 200 has a voltage-controlled oscillator 208 that generates a periodic signal. Phase comparator 204 compares the phase of the periodic signal from oscillator 208 with the input signal V. iThe phases of 202 are compared, and oscillator 208 is adjusted to maintain phase matching. PLL 200 also includes a loop filter 206, which can be a low-pass filter, etc. Loop filter 206 is typically used to determine loop dynamics and limit the reference frequency energy applied to the input of oscillator 208. Specifically, matching the input and output phases also requires keeping the input and output frequencies the same. Therefore, PLL 200 can additionally track the input frequency and match the output frequency accordingly.

[0038] Now for reference Figures 3A-3C The circuit configuration of an exemplary RF generator is typically shown in 300. Specifically, Figure 3A The circuit 300 of the RF generator is depicted. Figure 3B-3C Each section of circuitry 300 for an RF generator is depicted. The RF generator can provide a 250-watt RF source, functioning, for example, as part of a microwave power generation system shown and described herein. Any RF generator arranged in the system according to the teachings herein (e.g., RF generators 104a, 104b) can function according to exemplary circuitry 300. It should be understood that circuitry 300 is shown and described only to teach possible electrical configurations of RF generators within a system. Higher or lower power RF sources can be provided in other embodiments. Similarly, all components of circuitry 300 described herein are provided as an example of an effective circuit; it should be understood that in other cases, the circuitry can be configured differently while still effectively functioning as part of the system shown and described herein.

[0039] like Figure 3B As shown, circuit 300 includes a PLL reference input 304 (“Ref In”), a PLL reference output 302 (“Reference Out”), an electronic switch 306, a reference clock 308, and a synthesizer 310. Reference input 302 is connected to electronic switch 306, which in turn is connected to the reference clock. Reference clock 308 omits a periodic signal, such as a 1MHz clock signal. Reference output 302 is also connected to switch 306 and synthesizer 310, which can be a 2.4-2.5GHz synthesizer. Synthesizer 310 is connected to another electronic switch 320, which is used to pulse-modulate the signal for the desired pulse rise and fall times and pulse width.

[0040] Now for reference Figure 4An exemplary microwave power generation system, typically shown as 400, is part of a plasma generation system according to the art described herein. System 400 may function similarly to system 100 and vice versa, unless otherwise shown and described herein. Microwave power generation system 400 includes 10 connected RF generators 402a-j (configured, for example, similarly to solid-state generators 104a, 104b), but it should be understood that different numbers of generators 402a-j (collectively referred to as 402) may also be used. The power of the RF generators 402 may be 250 watts, and in some cases, other power levels may also be used. System controller 412 includes a processor and memory to control the operation of generator 400. System controller 412 may execute program instructions, such as algorithms, to cause system 400 to operate in accordance with the teachings herein. Furthermore, system controller 412 may include memory, including a database as described herein, for storing measurement data or input data. Combined power from generators 402 is provided to processing chamber 408.

[0041] Each RF generator 402 includes its own reference input 404 and reference output 406, which can be configured similarly to reference input 302 and reference output 304. Specifically, reference input 404 and output 406 are connected between RF generators 402 for PLL operation. Reference input 404 and output 406 connect each RF generator 402 to the same electronic switch 306 (see [link to electronic switch]). Figures 3A-3C The circuit 300 connects each RF generator 402 to the same reference clock 308, causing them to operate with the same period signal. As described above, sharing the same clock 308 causes phase-locked loop (PLL) operation among the RF generators 402. This allows phase linking of all RF generators 402, resulting in the most efficient total power of the combined RF generators 402 with no power loss.

[0042] For example, now refer to Figure 7 An exemplary diagram of the combined generator power is shown. The power output from each individual generator 402 is shown in Figure 702 above. The combined power of all generators 402 is shown in Figure 704 below. Phase linking allows the outputs of generators 402 to be superimposed on top of each other without overlap. Similarly, each generator 402 individually outputs power with an amplitude P1. Assuming there are “n” generators 402, the generators are phase linked and therefore their combined power is a multiple of “n” multiplied by P1. This creates the maximum sum of all individual generators (amplitude “n x P1”), as shown in Figure 704. This is consistent with… Figure 1 The power combination of generator 104 is similar; they are also arranged in a PLL. In contrast, the lack of phase linking leads to inefficiency when the power of individual RF generators is added together.

[0043] Refer again Figures 3A-3C and such Figure 3C As shown, circuit 300 includes a forward power detector 312 and a forward / reflected power detector 314, which can be used to measure impedance in real time by monitoring multiple signals and analyzing the data via IQ modulator 316. An RF signal is applied to the input of RF transconductance amplifier 318 and then demodulated into an I / Q baseband signal ("I" refers to the "in-phase" component of the signal, and "Q" represents the quadrature component) by IQ modulator 316 using a quadrature LO signal. The quadrature LO signal is generated from within the LO source (e.g., synthesizer 310) via a 90° phase shifter.

[0044] Now for reference Figure 5 An exemplary schematic functional block diagram of the circuitry for I / Q modulator 500 is shown. Other I / Q modulators described herein, such as I / Q modulator 316, can be configured according to I / Q modulator 500. In some specific exemplary embodiments, the design incorporates a Texas Instruments TRF372017 integrated IQ modulator PLL / VCO, or similar circuitry. The TRF372017 is a high-performance, high-linearity, low-noise IQ modulator and an integer-fractional PLL / VCO. The “LO” can be used as an output with a separate divider, but can also accept input from an external LO or VCO, which in this exemplary embodiment is a reference signal from synthesizer 310.

[0045] BB1 502 is a set of differential signals related to the positive and negative aspects of the in-phase component. BB1 504 is a set of differential signals related to the positive and negative aspects of the quadrature component. This refers to a pair of periodic signals with a 90° phase difference. In-phase and quadrature components refer to two sine waves with the same frequency and a 90° phase difference. By convention, the "I" signal is a cosine waveform, and the "Q" signal is a sine waveform. Since the sine wave is offset by 90° relative to the cosine wave, another way to express this is that the sine and cosine waves are "quadrature".

[0046] Now for reference Figure 6An exemplary polar plot of the I / Q signal (e.g., as part of circuit 300) is typically shown at 600. When a carrier is modulated with a waveform that slightly alters the carrier frequency, the modulated signal can be considered a phasor. As a phasor, it has a real part and an imaginary part. The real part is associated with in-phase or "I" (horizontal axis 602), while the imaginary part is quadrature or "Q" (vertical axis 604). Using the "I" and "Q" components of the modulated signal and the receiver already locked to the carrier signal, information can be shown on the polar plot 600. Once the RF signal is plotted, it can be represented in polar coordinates by amplitude and phase, or in xy coordinates by the amplitudes of the x and y vectors. Quadrature signals are generated by mixing 90 degrees. The amplitude and polarity of the I / Q signal determine the translational amplitude and phase of the I / Q vector (modulated RF carrier). Knowing the amplitude and phase, the voltage standing wave ratio (VSWR) and complex reflection coefficient can be calculated.

[0047] Refer again Figure 4 By operating multiple interconnected generators 402 into a single cavity or plasma source, such as processing chamber 408, real-time impedance measurements can be performed at the entrance of the processing chamber 408 where the input (e.g., an antenna) enters, and thus the VSWR can be determined. Knowing the VSWR and the complex reflection coefficient, the phase and amplitude of the microwave or RF energy in the processing chamber 408 can be calculated. The following are exemplary, but not unique, formulas for doing this:

[0048] ρ=V max / V min Equation 1

[0049] Γ=(1-ρ) / (1+ρ) Equation 2

[0050] Γ∠°=V ref / V fwd Equation 3

[0051] Γ=(Z L –Z0) / (Z L +Z0) Equation 4

[0052] In the above equation, Z L Z0 and Z1 are the load and characteristic load impedances, respectively. The variable ρ is the voltage standing wave ratio (VSWR). max It is the maximum voltage defined in the VSWR maximum voltage, and V min This is the minimum voltage defined in the VSWR minimum voltage for a typical radiation source. Γ is the absolute value of the reflection coefficient, which is usually defined as Γ∠°, where ∠° is the phase defined associated with the complex reflection coefficient. V ref It is the reflected voltage and V fwd It is either the forward or incident voltage.

[0053] In light of the above, system 400 calculates the spatial impedance associated with each generator 402. Knowing the spatial impedance of each generator 402, system 400 can calculate the spatial impedance for all generators 402, thus providing the impedance of all associated inputs in processing chamber 408. System controller 412 can then adjust the inputs to processing chamber 408 to manipulate and adjust the inputs, as discussed in more detail herein. By using multiple inlets to chamber 408 and by adjusting the phase, amplitude, and frequency of each individual generator 402, system 400 can manipulate the plasma in spatial configuration and manner at different locations to generate a desirable homogeneous plasma in terms of amplitude and density, mitigating the drawbacks of the conventional methods discussed herein.

[0054] Similarly, and through another example, refer again... Figure 1 In this system, where substrate 124 (or semiconductor wafer) is located within processing chamber 122, system 100 is capable of calculating the impedance of each RF generator output 120a, 120b or processing chamber input 112a, 112b. System 100 can then use a computer and algorithm-based software to manipulate and adjust the phase, amplitude, and frequency of all inputs 112a, 112b and plot the resulting output. Furthermore, the phase, amplitude, and frequency can be varied to adjust uniform plasma performance, resulting in better process performance, faster throughput, and better and improved yield, as well as less variation between substrate or wafer runs. In this way, by using multiple entries and adjusting the phase, amplitude, and frequency of each individual RF or microwave input energy, plasma at different locations can be spatially configured and manipulated to generate ideal uniform plasma and density in terms of amplitude and density, and also mitigates the drawbacks of the conventional methods described herein.

[0055] By inducing a uniform plasma, the performance of semiconductor processing substrates can be effectively improved. A uniform plasma can provide faster performance because, in the presence of a non-uniform plasma, the substrate undergoing semiconductor processing (e.g., substrate 124) will be exposed to over-processing, such as over-etching, over-ashing, or over-deposition, to cover wafer areas exposed to lower plasma amplitude or intensity. By eliminating this over-processing discussed herein, the throughput of semiconductor processing is improved. Furthermore, a uniform plasma generated according to the exemplary embodiments can provide better yield because over-processing (over-etching, over-ashing, and over-deposition) as described above typically results in less than ideal yields, as over-processing can damage the padding layer generated by previous processing steps. Additionally, variations between runs can be mitigated by using a uniform plasma. At each desired step taken during the multiple steps required to complete the finished substrate 124, a uniform plasma will provide the same semiconductor performance across the entire substrate 124.

[0056] Furthermore, degradation of the processing chamber (e.g., plasma tube or processing cavity) remains a problem in plasma generation systems and processes. In some cases, system 100 can measure impedance continuously or at specific time intervals and store the impedance changes over time in a database or similar source. When a surface within the processing chamber is eroded, the impedance of the eroded surface can be compared with the impedance data stored in the system database to determine if the surface has been eroded. This allows for accurate monitoring of the processing cavity's lifespan and the implementation of appropriate actions.

[0057] Now for reference Figure 8A , 8B The system described in this paper can be configured to use the above-mentioned techniques to determine what process gas is being processed by knowing whether the impedance of the plasma is capacitive or inductive. Figure 8A The Smith chart 800 is shown; it is a circular microwave or RF impedance diagram used to determine the characteristics of microwave or RF power in a transmission system. Figure 8B An exemplary Smith chart 802 is shown, which has been labeled to illustrate how the Smith chart can be utilized within the system described herein. The Smith chart 802 includes the VSWR (ρ) of the energy, the reflectance coefficient (Γ), and the phase. The contour lines are divided, with one half designated as capacitive and the other half as inductive. The system can then determine the properties of the process gas by comparing the results with a lookup table. In some exemplary embodiments, the lookup table may include the characteristic impedances of all typical gases used in the processing of semiconductor substrates.

[0058] For example, a system (e.g., system 100, 400) may include a comprehensive database of all semiconductor processing gases. Specifically, the database may include gases most commonly used in plasma generation processes, such as O2, N2, H2, Ar, fluorine-based gases, chlorine-based gases, and combinations thereof. References to these gases may be stored in the database along with their associated impedances measured according to this disclosure. The measured impedance of an unknown gas can then be compared with the database to determine the identity of the unknown gas. This process of identifying processing gases can be advantageous. For example, if the impedance of the running plasma gas is recorded and reported back to the plant, it can then be determined what gas the end user is running in their semiconductor processing formulation.

[0059] This technique for monitoring the impedance of processing chambers (e.g., chambers 122, 408) can also be used to determine the lifespan or replacement time of chambers 122, 408 by monitoring impedance changes. In some cases, systems 100, 400 can measure impedance and store the impedance changes over time continuously or at specific time intervals in a processor, database, etc. Normal etching and degradation of chambers 122, 408 will cause changes in chamber impedance, thus indicating etching of chambers 122, 408. The impedance of the etched surface can be compared with impedance data stored in the system database to determine that the surface has been etched. In this way, the lifespan of chambers 122, 408 can be accurately monitored and appropriate actions can be taken. This is advantageous because the end-of-life of chambers 122, 408 can be warned to semiconductor manufacturing plant users by systems 100, 400. When the impedance of the plasma processing chambers 122 and 408 changes due to the degradation of the plasma tube surface caused by the interaction between the plasma and the exposed surface, systems 100 and 400 can generate one or more series of messages and display them to the user to inform them of the current status. Exemplary messages may include "Tube corrosion nearing maintenance time," "Warning: Tube damaged and needs replacement," and / or other warning or replacement messages to inform the user of the status of systems 100 and 400 and / or potentially recommended or required maintenance actions. This is particularly beneficial in semiconductor processing, where "uptime" is critical. Therefore, it is very helpful to inform end users in advance of potential maintenance actions from the perspective of predicting and planning possible downtime.

[0060] Now for reference Figure 9 A block diagram of an exemplary power generation system 900 is shown. System 900 can be configured to generate electricity similar to systems 100 and 400 previously described, unless otherwise shown and described herein.

[0061] System 900 includes multiple individual generator modules 902a-d (collectively referred to as 902) powered by power supply 910 and connected to a PLL. System 900 employs a high-frequency daisy chain to allow coherent excitation of multiple RF amplifier chains and, for example, 360-degree phase shifters with a 1.4-degree step size. It should be understood that although four individual 1kW generator modules are shown as an example, different numbers of generator modules 902 and generator modules of different power can be used in other embodiments. Unlike the other systems 100, 400 described herein, generator modules 902 do not need to be connected to a shared reference clock; other steps are taken to achieve phase optimization. The power from generator modules 902 is combined in power combiner 904 and optimized for multiple channels. The power can then be provided to a source (not shown herein) via waveguide output 906. As mentioned above, the source can be a processing chamber for processing semiconductor substrates or for drying food or other applications.

[0062] System 900 also includes a processing module 908 that can execute program instructions, such as algorithms, to cause system 900 to operate in accordance with the teachings herein. Processing module 908 may also include memory for storing measurement data or input data, including a database. Processor 908 is connected to input / output (I / O) device 912. I / O device 912 may include input devices, such as known buttons, keyboards, mice, or other input devices, that allow a user to input data, control, set, or otherwise change system 900. I / O device 912 also includes an output section that can display information about system 900 to the user. For example, I / O device 912 may include output capabilities such as warning lights or display screens for graphics, warnings, or other visual indicators.

[0063] In conventional systems, amplitude and phase variations arising from device non-uniformity or manufacturing tolerances can lead to imperfect power summation across different power modules, resulting in reduced combination efficiency. In contrast, System 900 combines power within Combiner 904 to balance the phase and amplitude of various channels. Specifically, System 900 employs a method for optimizing the phase between its channels. System 900 programs the amplitude and phase of each generator module 902 and measures the output power of Combiner 904 to determine the optimal phase for each generator module 902 to maximize output power while minimizing losses.

[0064] The system 900 can execute algorithms using various optimization techniques to maximize output power. One such optimization technique includes performing a binary search to phase-align two channels. By plotting the output power of system 900, it can be seen that the combined output power P(θ) of system 900 as a function of phase angle is unimodal (i.e., it has only one minimum / one maximum). Therefore, in some cases, binary search can be applied to find the optimal value. For example, the symbol f(x) is used herein for P(θ). Given an interval for f(x), a minimum is bracketed when there is a triple of points a<b<c such that f(b) is less than both f(a) and f(c). In this case, the function (a non-singular function) has a minimum in the interval [a, c]. Then the binary search algorithm selects a new point x either between a and b or between b and c. For the present example, assume a point x is selected between b and c. The function f(x) is then evaluated.

[0065] If f(b)<f(x), the new bracketing triple of points is (a; b; x), as shown in Figure 10A 1000a. If f(b)>f(x), the new bracketing triple of points is (b; x; c), as shown in Figure 10B 1000b. In either case, the new triple is an abscissa whose ordinate is the best minimum achieved so far. This process is repeated until the interval is sufficiently small, which can be based on the chip resolution limitation of the system 900. Accordingly, multiple repetitions can be performed until the interval matches the chip resolution of the system 900.

[0066] The midpoint b of the optimal bracketing interval (a; b; c) has a fractional distance of 0.38197 from a and 0.61803 from b, as shown in the following formula:

[0067]

[0068]

[0069] The fractions in equations 5 and 6 are the "golden section" or "golden ratio". Therefore, the next point to be used is the fraction 0.38197, which is placed in the larger of the two intervals (measured from the center point of the triple). Note that this method can be used to find either the minimum or the maximum output power. In some cases, finding the minimum can be a more robust and faster method because the gradient near the minimum is much higher. In addition, using the minimum allows amplitude optimization to be subsequently performed. The disadvantage is that when using the minimum, the system 900 is forced into the region of the worst configuration.

[0070] The amplitude P(θ) of the combined output power of the system with a phase angle of 90° is also a periodic function. Therefore, trigonometric interpolation can be used; that is, the periodic function can be interpolated using the finite sum of trigonometric functions according to any of the following equations:

[0071]

[0072]

[0073] In order to evaluate a k and b k The Goertzel-Reinsch algorithm or the direct discrete Fourier transform algorithm can be used. In this example, only the first coefficients a1 and b1 are meaningful, so a more complete Fourier series analysis would only increase complexity without providing any additional advantage. In some cases, this method can be more robust and faster than the bisection method discussed earlier. However, this method requires values ​​across the entire phase range, including phase values ​​in the worst-case configuration region.

[0074] The exemplary method described above is used to describe optimization when two amplifiers (e.g., two generator modules 902) drive combiner 904. When the two generator modules 902 drive combiner 904 and combine four channels in the output of combiner 904, optimization can be performed by first turning on channels 1 and 2. Channel 2 is then optimized to match channel 1 according to the algorithm described above. Then channel 2 is turned off and channel 3 is turned on. Channel 3 is then optimized to match channel 1 according to the algorithm described above. Then channel 3 is turned off and channel 4 is turned on. Channel 4 is then optimized to match channel 1 according to the algorithm described above. Thus, all channels have been optimized to match channel 1, and therefore all phase matching has been achieved.

[0075] When using the additional generator module 902, channel optimization can be performed one channel at a time, and then repeated as needed. Assuming there are four channels, channel 1 can remain constant (period 0). Then channel 2 can rotate with the period of channel 1. Then channel 3 can rotate with the period of channel 2. Then channel 4 can rotate with the period of channel 3. This allows for the simultaneous output of different frequencies from the combiner 904.

[0076] For example, when four generator modules 902 drive the combiner 904, the optimization of the four channels can be performed as follows. First, all channels are opened. Then, optimization is performed on channel 2 to match the sum of the other channels with one of the algorithms described above. This matches channel 2 to the original sum of channels 1, 3, and 4. Then, optimization of channel 3 can be performed to match the sum of the other channels with one of the algorithms described above, matching channel 3 to the sum of channels 1 and 4 plus the improved sum of channel 2. Then, optimization of channel 4 can be performed to match the sum of the other channels with one of the algorithms described above, including the improvements to channels 2 and 3. These steps of optimizing channels 2-4 can then be repeated until the matching is satisfactory for the desired accuracy of the entire system 900.

[0077] All orientations and arrangements of the components shown herein are for illustrative purposes only. Furthermore, those skilled in the art will understand that in alternative embodiments, the function of multiple elements may be performed by fewer elements or a single element. Similarly, in some embodiments, any functional element may perform fewer or different operations than those described with respect to the illustrated embodiments. Moreover, in certain embodiments, functional elements shown as different for illustrative purposes may be incorporated into other functional elements.

[0078] While the subject matter has been described with respect to preferred embodiments, those skilled in the art will readily understand that various changes and / or modifications can be made to the subject matter without departing from its spirit or scope. For example, each claim may be dependent on any or all claims in various dependent manners, even if such a claim was not initially claimed.

Claims

1. A plasma generation system, comprising: A reference clock, configured to generate a reference signal; Multiple solid-state generator modules, each solid-state generator module is linked to an electronic switch and each electronic switch is linked to the reference clock, each solid-state generator module is configured to generate an output based on a reference signal from the reference clock; A processing chamber configured to receive the outputs of at least two of the solid-state generator modules for combining the outputs of the solid-state generator modules therein; as well as A database that stores impedance values ​​for various gases. The system is also configured to monitor the impedance of the processing chamber over time, and The system is further configured to use the database to identify the processing gas inside the processing chamber based on the change in impedance of the processing chamber over time.

2. The plasma generation system of claim 1 further includes an I / Q modulator configured to demodulate the signal at the input of the processing chamber into an I / Q signal, wherein, The plasma generation system is also configured to: Determine the voltage standing wave ratio (VSWR) and reflection coefficient of the I / Q signal; The first impedance of one of the solid-state generator modules is calculated based on VSWR and the reflection coefficient; and The second impedance is used to calculate the combined output power of the solid-state generator module in the processing chamber based on the first impedance.

3. The plasma generation system according to claim 2, wherein, The system is also configured to adjust the phase, amplitude, and frequency of at least one of the solid-state generator modules based on the second impedance.

4. The plasma generation system according to claim 1, wherein, The system is also configured to determine the remaining lifespan of the processing chamber based on the change in impedance of the processing chamber over time.

5. The plasma generation system according to claim 4, wherein, The plasma generation system is configured to issue a warning based on the remaining lifespan of the processing chamber.

6. The plasma generation system according to claim 1, wherein, The solid-state generator module is connected in a phase-locked loop (PLL) so that the output of the solid-state generator module has a shared phase.

7. The plasma generation system according to claim 1, wherein, Each solid-state generator module includes: The PLL reference input connected to the electronic switch; and A PLL reference output is connected to the electronic switch and the synthesizer, which is connected to a second electronic switch to pulse modulate the output of the solid-state generator module.

8. A method for generating electricity using a power generation system, comprising: Multiple outputs are generated using multiple solid-state generator modules; and Phase optimization techniques are used in the combiner to combine the outputs of the solid-state generator modules from multiple channels to generate in-phase combined output power. The plurality of channels includes three channels and the phase optimization technique includes: Open the channel; Determine the first, second, and third channels; The second channel is phase-shifted based on the sum of the first and third channels to produce an optimized second channel; and The third channel is phase-shifted based on the sum of the first channel and the optimized second channel.

9. The method of claim 8, further comprising at least one additional channel, wherein, The phase optimization technique includes: for each additional channel, phase shifting the additional channel to produce an optimized additional channel based on the sum of all other channels including any optimized channel.

10. The method according to claim 8, wherein, The steps of phase shifting the second channel, phase shifting the third channel, and phase shifting the additional channel are repeated multiple times.

11. The method according to claim 8, wherein, The phase optimization technique includes using an algorithm to determine the phase shift of at least one channel, the algorithm including at least one of the following: bisection method, Goertzel-Reinsch algorithm, or discrete Fourier transform.

12. The method of claim 8, further comprising providing the in-phase combined output power to the waveguide output.

13. The method according to claim 8, wherein, The solid-state generator module is connected in a phase-locked loop (PLL) so that the output of the solid-state generator module has a shared phase.

14. A method for generating electricity using a power generation system, comprising: Multiple outputs are generated using multiple solid-state generator modules; and Phase optimization techniques are used in the combiner to combine the outputs of the solid-state generator modules from multiple channels to generate in-phase combined output power. The plurality of channels includes three channels and the phase optimization technique includes: Determine the first, second, and third channels; Open the first channel and the second channel; The second channel is phase-shifted to match the output of the first channel; Close the second channel and open the third channel; and The third channel is phase-shifted to match the output of the first channel.

15. The method of claim 14, further comprising at least one additional channel, wherein, The phase optimization technique includes: For each additional channel, the first channel and the additional channel are turned on, all other channels are turned off, and the additional channel is phase-shifted to match the output of the first channel.

16. A power generation system, comprising: Multiple solid-state generator modules are configured to generate multiple outputs; and A combiner configured to combine the outputs from multiple channels of the solid-state generator module using phase optimization techniques to generate in-phase combined output power. in: The plurality of channels includes three channels; and The phase optimization technique includes: Open the channel; Determine the first, second, and third channels; The second channel is phase-shifted based on the sum of the first and third channels to produce an optimized second channel; and The third channel is phase-shifted based on the sum of the first channel and the optimized second channel.

17. The power generation system of claim 16, further comprising at least one additional channel, wherein, The phase optimization technique includes: for each additional channel, phase shifting the additional channel to produce an optimized additional channel based on the sum of all other channels including any optimized channel.

18. The power generation system according to claim 16, wherein, The system is configured to repeat the steps of phase shifting the second channel, phase shifting the third channel, and phase shifting the additional channel multiple times.

19. The power generation system according to claim 16, wherein, The phase optimization technique includes using an algorithm to determine the phase shift of at least one channel, the algorithm including at least one of the following: bisection method, Goertzel-Reinsch algorithm, or discrete Fourier transform.

20. The power generation system according to claim 16, further comprising a waveguide output, wherein, The system is configured to provide the in-phase combined output power to the waveguide output.

21. The power generation system according to claim 16, wherein, The solid-state generator module is connected in a phase-locked loop (PLL) so that the output of the solid-state generator module has a shared phase.

22. A power generation system, comprising: Multiple solid-state generator modules are configured to generate multiple outputs; and A combiner configured to combine the outputs from multiple channels of the solid-state generator module using phase optimization techniques to generate in-phase combined output power. The plurality of channels includes three channels and the phase optimization technique includes: Determine the first, second, and third channels; Open the first channel and the second channel; The second channel is phase-shifted to match the output of the first channel; Close the second channel and open the third channel; and The third channel is phase-shifted to match the output of the first channel.

23. The power generation system of claim 22, further comprising at least one additional channel, wherein, The phase optimization technique includes: For each additional channel, the first channel and the additional channel are turned on, all other channels are turned off, and the additional channel is phase-shifted to match the output of the first channel.

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