Injection-locked magnetron system for stable microwave generation

Abstract

An apparatus is provided herein. The apparatus includes a magnetron configured to generate microwave power, the magnetron including a built-in antenna, a solid-state generator configured to generate a reference signal, at least one circulator connected to the magnetron and the solid-state generator via a plurality of waveguides, the at least one circulator configured to direct the reference signal from the solid-state generator to the magnetron, and an antenna injection port comprising the built-in antenna of the magnetron, the antenna injection port configured to receive the reference signal. The reference signal injection-locks the magnetron such that a frequency of the microwave power generated by the magnetron is synchronized with a frequency of the reference signal.

Description

INJECTION-LOCKED MAGNETRON SYSTEM FOR STABLE MICROWAVE GENERATIONFIELD OF INVENTION

[0001] The present disclosure relates to microwave generation systems, and more particularly to an injection-locked magnetron system for producing stable and controllable high-power microwave output.BACKGROUND

[0002] Microwave generators are widely used in various industrial and scientific applications, including plasma generation, materials processing, and heating. These generators typically employ either magnetron or solid-state technology to produce high-frequency electromagnetic waves. Magnetron-based systems offer high power output and efficiency, but may face challenges with frequency stability and precision control. Solid-state generators provide better frequency control and stability, but often at lower power levels and higher costs per watt. As applications demand increasingly precise and stable microwave sources, there is ongoing interest in techniques that can combine the advantages of both magnetron and solid-state technologies.SUMMARY

[0003] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0004] According to an aspect of the present disclosure, an apparatus is provided. The apparatus includes a magnetron configured to generate microwave power, the magnetron including a built-in antenna, a solid-state generator configured to generate a reference signal, at least one circulator connected to the magnetron and the solid-state generator via a plurality of waveguides, the at least one circulator configured to direct the reference signal from the solid-state generator to the magnetron, and an antenna injection port comprising the built-in antenna of the magnetron, the antenna injection port configured to receive the reference signal, wherein the reference signal injection-locks the magnetron such that a frequency of the microwave power generated by the magnetron is synchronized with a frequency of the reference signal.

[0005] According to another aspect of the present disclosure, an apparatus is provided. The apparatus includes a magnetron configured to generate microwave power, the magnetron including a built-in antenna, a solid-state generator configured to generate a reference signal, a first circulator connected to the magnetron and configured to direct microwave power from the magnetron to a process load and to direct the reference signal to the magnetron, a second circulator connected to the solid-state generator and the first circulator, the second circulator configured to direct the reference signal from the solid-state generator to the first circulator, an antenna injection port comprising the built-in antenna of the magnetron configured to receive the reference signal from the solid-state generator via the second circulator and the first circulator, waveguides connected to the first circulator and configured to direct the microwave power from the magnetron to a process load, and a water load connected to the second circulator and configured to absorb reflected power to protect the solid-state generator, wherein the reference signal injection-locks the magnetron such that a frequency of the microwave power generated by the magnetron is synchronized with a frequency of the reference signal.

[0006] According to yet another aspect of the present disclosure, an apparatus for plasma generation is provided. The apparatus includes a plurality of injection-locked magnetrons, each magnetron configured to generate microwave power and including a built-in antenna, a plurality of solid-state generators, each solid-state generator configured to generate a reference signal for injection-locking a corresponding magnetron, a plurality of circulators, each circulator connected to a corresponding magnetron and solid-state generator and configured to direct the reference signal to the corresponding magnetron, a plurality of antenna injection ports, each antenna injection port comprising the built-in antenna of a corresponding magnetron and positioned within a plasma chamber, a plurality of impedance matching networks, each impedance matching network connected to a corresponding magnetron and configured to optimize coupling between the magnetron and a plasma load, a control system configured to synchronize frequencies and phases of the plurality of solid-state generators to enable coherent operation of the plurality of injection-locked magnetrons, and a plasma monitoring system configured to provide real-time feedback on plasma conditions within the plasma chamber, wherein the plurality of injection-locked magnetrons are configured to generate plasma simultaneously at multiple points within the plasma chamber.

[0007] According to other aspects of the present disclosure, the control system is configured to position the plurality of impedance matching networks to optimize ignition success rate across all antenna channels, activate the plurality of injection-locked magnetrons simultaneously at respective ignition condition power levels, activate the plurality of solid-state generators to achieve synchronized injection-locking across the multi-antenna array, evaluate plasma ignition success across the plurality of antennas, continuously monitor plasma state using the plasma monitoring system, and dynamically adjust frequencies and phases of the plurality of solid-state generators to optimize plasma parameters and distribution across the plasma chamber.

[0008] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.BRIEF DESCRIPTION OF FIGURES

[0009] Non-limiting and non-exhaustive examples are described with reference to the following figures.

[0010] FIG. 1 is a schematic diagram of a magnetron power system, in accordance with knowledge available in the art;

[0011] FIG. 2 is a schematic diagram of a microwave solid state generator set-up, in accordance with knowledge available in the art;

[0012] FIG. 3 is a schematic diagram of a magnetron injection locking set-up with solid state generator, in accordance with an aspect of the present disclosure;

[0013] FIG. 4 is a schematic diagram of another magnetron injection locking set-up with solid state generator, in accordance with another aspect of the present disclosure;

[0014] FIG. 5 illustrates a multi-source microwave wafer annealing system utilizing frequency injection technology for uniform heating of semiconductor wafers, in accordance with the present invention;

[0015] FIG. 6 is a flow chart illustrating a wafer annealing process, in accordance with the present invention;

[0016] FIG. 7 illustrates a remote plasma source utilizing the injection locked magnetron, in accordance with the present invention;

[0017] FIG. 8 illustrates a flowchart concerning the functioning of a remote plasma source;

[0018] FIG. 9 illustrates an in-situ plasma generation system that utilizes injection locked magnetron technology to create plasma directly within the process chamber, in accordance with the present invention;

[0019] FIG. 10 illustrates a flowchart for in-situ plasma generation, in accordance with the present invention, and

[0020] FIG. 11 illustrates a flowchart for multi-antenna configuration plasma generation, in accordance with the present invention.DETAILED DESCRIPTION

[0021] The following description sets forth exemplary aspects of the present disclosure. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein.

[0022] FIG. 1 illustrates a magnetron power system 100 according to knowledge available in the art.

[0023] A magnetron power system 100 may include a power supply unit 102, a power supply line 104, a magnet 106, a magnetron 108, a waveguide launcher 110, and a built-in antenna 112. Typically, a magnetron is made of the following built-in subparts: permanent magnets or electromagnets, such as the two magnets or discs labeled as 106 in FIG. 1, the magnetron internal cavity, and a built-in antenna 112. In some embodiments, the built-in antenna 112 may be a monopole antenna. The waveguide launcher 110 is not a subpart of magnetron 108. The magnetron may be installed into a waveguide launcher that has an output port 9 and may be connected to other devices not shown in the picture (circulators, applicators / load).

[0024] The power supply unit 102 may be configured to provide power to magnetron 108. In some cases, the power supply unit 102 may be an AC / DC power supply unit capable of delivering high voltage and low current, such as 9kV and 1.5 A DC. The power supply line 104 may connect the power supply unit 102 to the magnetron 108, enabling the transfer of electrical power.

[0025] The magnetron power system 100 may be configured to generate microwave power. In some embodiments, the magnetron power system 100 may include an internal cavity and a built-in antenna 112. The internal cavity may serve as a resonant chamber where electromagnetic waves are generated. The built-in antenna 112 may extend into cavity 114, facilitating the coupling of electromagnetic energy into a waveguide launcher.

[0026] Magnet 106 may be positioned above magnetron 108. In some cases, the magnet 106 may generate a magnetic field that influences the behavior of electrons within the magnetron. Magnetrons use either electromagnets or permanent magnets.

[0027] The waveguide launcher 110 may be connected to the magnetron 108. The built-in antenna 112 delivers power into the waveguide launcher 110, which then delivers it into either one of an applicator, tuning system, or load (not shown in the figure).

[0028] In some cases, the arrangement of components in the magnetron power system 100 may allow for efficient generation of microwave power. The power supply unit 102 may deliver electrical energy through the power supply line 104 to the magnetron 108. The magnetron 108, influenced by the magnetic field from magnet 106, may generate electromagnetic waves within its internal cavity. These waves may then be coupled out of the system via the monopole antenna 112 and the waveguide launcher 110 and other possible waveguide components.

[0029] FIG. 2 is a schematic diagram of a microwave solid state generator set-up, in accordance with knowledge available in the art.

[0030] A solid-state generator system test set-up 200 may include a phase-locked loop (PLL) source 202, a power supply unit 204, a power supply line 206, an antenna 210, and a waveguide launcher 214. In a solid-state generator the waveguide antenna is a separate component that is added and is labeled herewith as 210. The antenna applicator 214 is a waveguide launcher and can deliver power to other waveguide components not shown in the figure, such as circulators, applicator / load, etc.

[0031] The phase-locked loop (PLL) source 202 may be configured to generate a reference signal. The PLL source 202 acts as a microwave source that needs to be amplified by the solid-state generator. The phase-locked loop (PLL) source 202 may provide precise frequency control for the injection locking operation.

[0032] The power supply unit 204 may be configured to provide power to the solid-state amplifier 212. The power supply line 206 may connect the power supply unit 204 to other components of the system, enabling the transfer of electrical power.

[0033] The waveguide launcher 214 may be connected to the antenna 210 and may provide a means for directing the electromagnetic energy from the antenna 210 to other components of the system or to a load.

[0034] In some cases, the solid-state generator system test set-up 200 may be used to study and optimize the injection locking process. The phase-locked loop (PLL) source 202 may generate a reference signal with precise frequency control. This reference signal may be amplified by the solid-state amplifier and injected into a magnetron (not shown in FIG. 2) through the antenna 210 and antenna applicator 214.

[0035] The solid-state generator system test set-up 200 may be used to develop an automatic locking system for determining frequency and power of the reference signal. In some cases, the phase-locked loop (PLL) source 202 may be adjusted to find the optimal parameters for achieving stable injection locking.

[0036] FIG. 3 is a schematic diagram of a magnetron injection locking set-up with solid state generator, in accordance with an aspect of the present disclosure. More precisely, FIG. 3 illustrates a magnetron injection locking set-up 300 with solid state amplifier 314 according to an embodiment of the present invention.

[0037] A magnetron injection locking set-up 300 with solid state amplifier 314 may include a process load 302, waveguides 304, at least one circulator 306, a magnetron 308 including a built-in antenna, a magnetron launcher 310, an antenna injection port 312 comprising the built-in antenna of the magnetron 308, and a solid-state generator 314.

[0038] The magnetron 308 may be configured to generate microwave power. In some cases, magnetron 308 may have a natural frequency at which the magnetron 308 tends to oscillate. The solid-state generator 314 may be configured to generate a reference signal for injection-locking the magnetron 308. In some cases, the solid-state generator 314 may generate the reference signal at a frequency within ±5 MHz of the natural frequency of the magnetron 308.

[0039] The at least one circulator 306 may be connected both to magnetron 308 and the solid-state generator 314 via waveguides 304. The at least one circulator 306 may be configured to direct the reference signal from the solid-state generator 314 to the magnetron 308. In some cases, the at least one circulator 306 may be configured to protect the magnetron 308 from reflected power.

[0040] The antenna injection port 312, comprising the built-in antenna of the magnetron 308, may be configured to receive the reference signal from the solid-state generator 314. In some cases, the reference signal may be injected into the magnetron 308 through the antenna injection port 312. The reference signal may injection-lock the magnetron 308 such that a frequency of the microwave power generated by the magnetron 308 is synchronized with a frequency of the reference signal. A 10 W power signal may be exemplarily injected.

[0041] The waveguides 304 may be configured to direct the microwave power from the magnetron 308 to the process load 302. In some cases, the process load 302 may be utilized for plastic preform heating in a bottle manufacturing process.

[0042] In some cases, the solid-state generator 314 may be configured to generate the reference signal at a power level at least three orders of magnitude lower than the microwavepower generated by the magnetron 308. For example, if the magnetron 308 generates 10 kilowatts of microwave power, the solid-state generator 314 may generate a reference signal with a power level of 10 watts or less.

[0043] The magnetron injection locking set-up with solid state amplifier 300 may operate as follows: The solid-state generator 314 may generate a reference signal. This reference signal may be directed by the at least one circulator 306 to the antenna injection port 312 of the magnetron 308. The antenna injection port 312 comprises the magnetron's own built-in antenna, in an embodiment of the present invention. The reference signal injection-locks the magnetron 308 such that the frequency of the microwave power generated by the magnetron 308 is synchronized with the frequency of the reference signal. The microwave power may then be directed through the waveguides 304 to the process load 302.

[0044] In some cases, the at least one circulator 306 may also function to protect the magnetron 308 from any power that may be reflected back from the process load 302 or the waveguides 304. This protection may help to ensure the stability and longevity of the magnetron 308.

[0045] The magnetron launcher 310 may be a piece of waveguide closed on one side, that allows to mount the magnetron 308.

[0046] FIG. 4 is a schematic diagram of another magnetron injection locking set-up with solid state generator, in accordance with another aspect of the present disclosure. More precisely, FIG. 4 illustrates a magnetron injection locking set-up with solid state amplifier 400.

[0047] A magnetron injection locking set-up with solid state amplifier 400 may include a process load 402, waveguides 404, a first circulator 406, a magnetron 408 including a built-in antenna, a magnetron launcher 410, an antenna injection port 412 comprising the built-in antenna of the magnetron 408, a second circulator 414, a water load 416, and a solid-state generator 418.

[0048] The first circulator 406 may be connected to the magnetron 408. In some cases, the first circulator 406 may be configured to direct microwave power from the magnetron 408 to the waveguides 404 and ultimately to the process load 402, and to direct a reference signal from the second circulator 414 to the magnetron 408.

[0049] The second circulator 414 may be connected to the solid-state generator 418 and the first circulator 406. In some cases, the second circulator 414 may be configured to direct the reference signal from the solid-state generator 418 to the first circulator 406 and to direct any reflected power to the water load 416.

[0050] The antenna injection port 412, comprising the built-in antenna of the magnetron 408, may be configured to receive the reference signal from the solid-state generator 418 via the second circulator 414 and the first circulator 406. In some cases, this dual circulator configuration may enhance the injection-locking process by providing improved isolation between the load reflected power and the magnetron 408.

[0051] The waveguides 404 may be connected to the first circulator 406 and may be configured to direct the microwave power from the magnetron 408 to the process load 402. In some cases, the process load 402 may be a plasma chamber or a plastic preform heating system.

[0052] The water load 416 may be connected to the second circulator 414. In some cases, the water load 416 may be configured to absorb any reflected power from the system, thereby protecting the solid-state generator 418 and improving the overall stability of the injectionlocking process. The water load 416 is designed to use any sort of cooling, even air. The choice of design depends on the power of the magnetron, that may be at hundreds of Watts or more. The water load 416 should withstand all the magnetron's power.

[0053] In some cases, the magnetron inj ection locking set-up with solid state amplifier 400 may be used with multiple injection-locked magnetrons in parallel. This configuration may allow for phase control between the multiple magnetrons, potentially increasing the total output power and providing more precise control over the microwave field distribution.

[0054] The inj ection locking technique used in the magnetron inj ection locking set-up with solid state amplifier 400 may improve the pulsing capabilities of the magnetron 408. In some cases, this improvement may result in faster switching times or more precise control over the pulse shape and duration.

[0055] In some embodiments, an auto-locked topology may be implemented using feedback from the magnetron 408's own output. This feedback may be sampled, amplified, and injected back into the magnetron 408 through its built-in antenna 412 In some cases, cable length, delay lines, and filters may be used for phase control in the feedback path to ensure proper synchronization and stability of the injection locking process.

[0056] The magnetron injection locking set-up with solid state amplifier 400 may be applied to various types of magnetrons at different frequencies, including 2.45 GHz range, 915 MHz range, 5.8 GHz and other frequency ranges. In some cases, the use of injection locking with 915 MHz magnetrons may extend the benefits of improved frequency stability and control to higher power applications.

[0057] The injection-locked magnetron system 300 or 400 combines the advantages of solid-state and magnetron technologies to produce stable, high-power microwave output. Asolid-state amplifier generates a low-power reference signal that is injected into the magnetron through an antenna injection port comprising the magnetron's built-in antenna. This reference signal inj ection-locks the magnetron such that the frequency of the microwave power generated by the magnetron is synchronized with the frequency of the reference signal, resulting in improved frequency stability and control.

[0058] The system utilizes circulators to direct the reference signal and protect components from reflected power. In one configuration, a single circulator connects the solid-state amplifier, magnetron, and waveguides. An alternative setup employs two circulators in series, with the first circulator connected to the magnetron and waveguides, and the second circulator positioned between the solid-state amplifier and the first circulator. This dualcirculator arrangement may provide enhanced isolation and protection for system components.

[0059] The dual-circulator configuration of FIG. 4 is preferred over the single-circulator configuration, since the single circulator structure protects the magnetron from reflected power, but the solid-state generator would fail to manage all the reflected power. The dual-circulator structure protects both the magnetron and the solid-state generator.

[0060] The solid-state amplifier typically generates a reference signal at a frequency within ±5 MHz of the magnetron's natural frequency. The power level of the reference signal can be several orders of magnitude lower than the magnetron's output power. For example, a 10-watt reference signal may be sufficient to control a magnetron generating 10 kilowatts of microwave power. The system maintains high efficiency, with only a slight decrease due to the addition of the solid-state amplifier.

[0061] Waveguides direct the microwave power from the magnetron to the process load, which may be used for various applications such as plasma generation or plastic preform heating in bottle manufacturing. The injection-locking technique allows for mild frequency control, typically within a range of ±5 MHz. This improved frequency stability and control may lead to benefits such as faster plasma ignition times and more consistent heating in industrial processes.

[0062] In some embodiments, the injection-locked magnetron system may be applied to various types of magnetrons, including exemplarily the 915 MHz range magnetrons. The use of injection locking with 915 MHz magnetrons may extend the benefits of improved frequency stability and control to higher power applications.

[0063] The inj ection locking technique used in the magnetron inj ection locking set-up may improve the pulsing capabilities of the magnetron. In some cases, this improvement may result in faster switching times or more precise control over the pulse shape and duration.

[0064] In some embodiments, an auto-locked topology may be implemented using feedback from the magnetron's own output. This feedback may be sampled, amplified, and injected back into the magnetron through the antenna injection port. In some cases, cable length, delay lines, and filters may be used for phase control in the feedback path to ensure proper synchronization and stability of the injection locking process.

[0065] The magnetron injection locking set-up may be used with multiple injection-locked magnetrons in parallel. This configuration may allow for phase control between the multiple magnetrons, potentially increasing the total output power and providing more precise control over the micro wave field distribution.

[0066] In some embodiments, the injection locking technique may facilitate plasma ignition over a wider pressure, flow, and chemistry space, or at lower power levels, or without supplemental electron source assistance. In plasma applications, locked magnetrons may offer advantages in terms of ignition flexibility and efficiency.

[0067] The solid-state amplifier may generate the reference signal at a power level at least three orders of magnitude lower than the microwave power generated by the magnetron. For example, a 10-watt reference signal may be sufficient to control a magnetron generating 10 kilowatts of microwave power. This significant power difference highlights the efficiency of the injection locking technique in controlling high-power microwave generation.

[0068] Although the magnetron generators and the solid-state generators 200 known in the art have a plurality of advantages and disadvantages, as enumerated below, neither one is capable of providing the advantages highlighted above for the apparatuses 300 and 400 of the present invention: The magnetron generators 100 illustrated in FIG. 1 have higher output power than the solid-state generators 200 illustrated in FIG. 2. The magnetron generators 100 have higher electrical to microwave conversion efficiency than the solid-state generators 200. The solid-state generators 200 have higher spectral purity than the magnetron generators 100. The solid-state generators 200 can be summed together in parallel while magnetron generators 100 cannot. The magnetron generators 100 have a lower cost per unit output power than solid state generators 200.

[0069] The configurations of the present invention find applicability in connection with wafer annealing, plasma generation, in-situ and remotely, and plasma generation with a set-up that comprises multiple antennas.

[0070] Wafer annealing demands precise thermal control, to heat only the very surface layers of semiconductor wafers, while preserving the bulk silicon substrate at ambient temperature. This selective heating requirement targets conductive, or metal films depositedon the wafer surface, necessitating temperatures in the range of 500-600°C to induce the desired phase structure changes in the deposited materials, without affecting the underlying silicon crystal structure. The process must achieve exceptional uniformity across large diameter wafers, particularly 12-inch (300mm) wafers that represent the current industry standard, where temperature variations of even a few degrees can result in non-uniform material properties and device performance degradation. Unlike conventional furnace annealing that heats the entire wafer volume or laser annealing that provides only localized treatment, microwave annealing exploits the shallow skin depth penetration of microwave energy to confine heating to the surface films. The challenge lies in distributing microwave power uniformly across the large wafer area, as traditional single-source microwave systems struggle to maintain consistent field strength and heating patterns over such dimensions. Additionally, the process requires rapid thermal cycling capabilities to minimize thermal budget impact on previously processed device layers, demanding precise control over heating rates, steady-state temperatures, and cooling profiles throughout the annealing sequence.

[0071] The present invention provides significant technical advantages over conventional wafer annealing approaches by utilizing multiple injection-locked magnetrons in a phased array configuration to achieve superior heating uniformity and control. Unlike furnace-based systems that heat the entire wafer volume and create unwanted thermal stress in the bulk silicon, or laser scanning systems that provide only localized treatment requiring complex mechanical positioning, the microwave phased array approach delivers precisely controlled surface heating through the shallow skin depth penetration of microwave energy. The frequency injection technology enables each magnetron to operate with exceptional spectral purity and phase stability, eliminating the mode hopping and frequency drift that plague conventional magnetron systems and cause heating non-uniformities. The ability to independently control the phase and frequency of each source in the array allows for dynamic beam steering and field shaping, enabling real-time compensation for wafer-to-wafer variations and process drift. This phase control capability transforms what would otherwise be multiple independent heating sources into a coherent system that can focus energy precisely where needed and redistribute power to eliminate hot spots or cold zones. Furthermore, the rapid frequency tuning capability of the injection-locked magnetrons enables millisecond-scale adjustments to the heating profile, providing the fast response times necessary for advanced process control and the ability to implement complex thermal recipes with multiple temperature plateaus and rapid transitions between different heating conditions.

[0072] The configurations proposed by the present invention propose the use of multiple frequency injection setups using dual circulator configuration, each magnetron having its own antenna inside the process chamber, and not combined in waveguide. The configurations also propose IR sensors for temperature monitoring and heating profile control, and a closed loop feedback control system.

[0073] FIG. 5 illustrates a multi-source microwave wafer annealing system utilizing frequency injection technology for uniform heating of semiconductor wafers. The system comprises multiple parallel signal paths (A, B, through Z) that converge into a common wafer annealing applicator 22 with a sensor 23.

[0074] Each signal path contains primary components including: an injection point 4 for the magnetron system, an injection-locked magnetron 10 including a built-in antenna, at least one circulator (not shown) configured to direct the reference signal to the magnetron, and an antenna injection port 4 comprising the built-in antenna of the injection-locked magnetron 10. The injection-locked magnetron 10 has the injection point 4 and the antenna injection port 4 as internal subsystems.

[0075] The injection points 4A, 4B, ..., 4Z receive control signals 21 from a solid state source for injection locking 20, which provides the low-power injection signal necessary for frequency stabilization and control of each magnetron.

[0076] The injection-locked magnetrons 10 A, 10B, ..., 10Z generate high-power microwave energy at precisely controlled frequencies and phases. Each magnetron's output is delivered through its respective antenna injection port 4 A, 4B, ... , 4Z into the wafer annealing applicator 22. This configuration enables independent control of each microwave source while maintaining phase coherence across the plurality of injection-locked magnetrons.

[0077] The coaxial cables 21 provide the signal path from the solid state injection source to each injection antenna, ensuring proper frequency injection into each magnetron. The wafer annealing applicator 22 serves as the common chamber where all microwave sources converge to provide uniform heating across the semiconductor wafer surface.

[0078] An applicator sensor 23 monitors the heating process, likely providing temperature feedback through infrared sensing or other measurement techniques to ensure that the desired heating profiles are achieved. This sensor enables closed-loop control of the annealing process.

[0079] The parallel architecture allows for phased array operation, where the relative phases of the multiple sources can be controlled to steer and focus the microwave energy for optimal heating uniformity across large diameter wafers (such as 300mm wafers). Each sourcecan be independently controlled for power and phase, enabling compensation for nonuniformities and providing precise temperature control across the wafer surface.

[0080] Once a source is elected as the main source, the other sources can be independently controlled with a phase change from 0° to 360°. A feedback loop concerning the sources will be described later in this document. This configuration addresses the challenge of achieving uniform microwave heating over large semiconductor wafers by utilizing multiple synchronized sources rather than attempting to achieve uniformity with a single large source, which would be technically difficult and less controllable.

[0081] The wafer annealing process 600, illustrated in FIG. 6, begins with the step of systematic activation of the microwave systems 602, where each injection locked magnetron in the array is brought online in a controlled sequence. The magnetrons are initially operated at reduced power levels to ensure stable startup conditions and prevent thermal shock to the semiconductor wafer. During this initialization phase, the system performs diagnostic checks on each magnetron to verify proper operation and readiness for the injection locking process.

[0082] Once the magnetron systems are stable, the solid state sources are activated in a step 604 to establish injection locking across all magnetrons in the array. The low-power solid state injection signals are precisely tuned, in a step 606, to each magnetron's operating frequency, creating the narrow spectrum generation that enables stable, coherent operation. The injection locking process synchronizes all magnetrons to operate at the same fundamental frequency while maintaining the ability to control individual phase relationships. This step is critical for achieving the phase coherence necessary for effective beam steering and uniform field distribution across the wafer surface.

[0083] With all magnetrons successfully locked, the applicator sensor system measures, in a step 608, the electromagnetic field distribution within the annealing chamber and across the wafer surface. The sensor, utilizing infrared detection or other non-contact measurement techniques, creates a real-time map of the heating pattern and compares this measured distribution against the predetermined target profile required for optimal annealing. Any deviations from the desired uniform heating pattern are identified and quantified, providing the feedback necessary for dynamic field correction.

[0084] Based on the field distribution measurements, the control system, in a step 610, automatically adjusts the frequencies and phases of the individual solid state injection sources to modify the overall field pattern. By varying the relative phases between magnetrons, the system can steer the combined microwave beam and redistribute energy to achieve better uniformity. Frequency adjustments allow for fine-tuning of the coupling efficiency and cancompensate for load variations as the wafer temperature changes during the annealing process. These adjustments are made in real-time, enabling continuous optimization of the heating profile.

[0085] Simultaneously with the frequency and phase adjustments, stub tuning is performed in a step 612 for each individual microwave system to optimize impedance matching between the magnetrons and their respective loads. The impedance matching process ensures maximum power transfer efficiency and minimizes reflected power that could destabilize the magnetrons or create non-uniform heating. Each channel's matching network is independently optimized, accounting for the specific load conditions presented by that magnetron's portion of the overall field pattern.

[0086] The process then returns to the field distribution measurement step 608, creating a continuous feedback loop that maintains optimal heating uniformity throughout the annealing cycle. This iterative approach allows the system to compensate for dynamic changes in the wafer's electromagnetic properties as it heats up, ensuring consistent annealing results across the entire wafer surface and from wafer to wafer in production environments.

[0087] Process gases enter the remote plasma applicator through the gas flow in port, where they are dissociated and ionized by the microwave energy to form the desired plasma chemistry. The plasma generates reactive radicals and other species that exit through the radicals out port and are transported to the application chamber where they interact with the semiconductor substrate. This configuration allows for the generation of highly reactive species while maintaining precise control over their delivery to the process surface.

[0088] A plasma monitoring sensor provides real-time feedback on plasma conditions, enabling closed-loop control of the plasma generation process. This sensor can monitor various plasma parameters such as optical emission, impedance changes, or other plasma characteristics to ensure consistent plasma conditions and rapid response to process variations. The monitoring capability is particularly important for applications requiring precise plasma chemistry control, such as atomic layer deposition (ALD) or selective etching processes.

[0089] The frequency injection technology enables rapid plasma ignition, which is crucial for processes requiring quick transitions between plasma-on and plasma-off states, such as plasma-enhanced ALD where millisecond-scale timing control is essential. The system can rapidly switch between different tuning conditions optimized for plasma ignition versus steadystate operation, providing the fast response times necessary for advanced semiconductor processing applications. This configuration represents a significant improvement overconventional plasma systems by combining the power advantages of magnetron sources with the stability and control benefits of solid-state injection locking technology.

[0090] FIG. 7 is a block diagram 800 of a remote plasma source utilizing the injection locked magnetron 400 of FIG. 4.

[0091] Remote plasma sources utilizing injection locked magnetron technology represent a significant advancement in semiconductor processing equipment, addressing critical challenges in plasma generation and control for advanced manufacturing applications. Unlike conventional in-situ plasma systems where the plasma is generated directly above the substrate, remote plasma sources create the plasma in a separate chamber or applicator, then transport the reactive species to the process chamber where they interact with the semiconductor wafer. This configuration provides superior process control by decoupling plasma generation conditions from substrate processing conditions, enabling independent optimization of both plasma chemistry and surface reactions.

[0092] The integration of injection locked magnetron technology into remote plasma sources offers substantial improvements in plasma stability and process repeatability compared to traditional magnetron-driven systems. The injection locking mechanism utilizes a low-power solid-state source to stabilize the high-power magnetron output, eliminating the frequency drift and mode hopping that commonly plague conventional magnetron systems. This frequency stabilization is particularly critical for plasma applications because even small variations in microwave frequency can dramatically affect plasma ignition characteristics, plasma density, and the resulting chemistry of reactive species generated within the plasma. The narrow spectrum generation achieved through injection locking ensures consistent plasma conditions from ignition through steady-state operation, providing the reliability necessary for high-volume semiconductor manufacturing.

[0093] The remote plasma configuration offers distinct advantages for processes requiring precise control of reactive species delivery, such as atomic layer deposition (ALD), selective etching, and surface cleaning applications. By generating the plasma remotely, the system can optimize gas residence time, plasma density, and radical generation efficiency without being constrained by the geometric requirements of the process chamber. The transport of radicals and other reactive species from the remote source to the application chamber allows for some degree of species selection, as different radicals have varying lifetimes and transport characteristics. This selective transport can be advantageous for processes that benefit from specific radical chemistries while minimizing unwanted plasma damage to sensitive device structures.

[0094] The injection locked magnetron technology enables rapid plasma ignition and precise frequency tuning capabilities that are essential for advanced semiconductor processes. The system can achieve millisecond-scale transitions between different operating conditions, making it particularly suitable for processes like plasma-enhanced ALD where rapid cycling between plasma-on and plasma-off states is required. The frequency injection approach also provides the ability to optimize different tuning conditions for plasma ignition versus steadystate operation, ensuring reliable plasma startup while maintaining optimal conditions for sustained plasma generation. This dual-mode capability addresses one of the fundamental challenges in plasma processing where the conditions required for reliable ignition often differ from those needed for optimal steady-state plasma chemistry and uniformity.

[0095] FIG. 7 illustrates a remote plasma source utilizing the injection locked magnetron 400. The figure shows a remote plasma applicator 720 that interacts with a solid state source for injection locking 721 to transmit a signal for injection locking to an injection point 704 for magnetron system 400. Via an output antenna 709 of the injection locked magnetron 400, signal is transmitted to the remote plasma source 722. The figure also shows the plasma monitoring sensor 723, the gas flow inlet 724, a radicals outlet 725 and an application chamber 726.

[0096] FIG. 8 illustrates a flowchart 800 illustrating the step by step functioning of a remote plasma source in accordance with the present invention.

[0097] The flowchart 800 begins with setting the pressure and flow setpoints, in a step 902, for the desired chemistry in the remote plasma chamber. This initial step 802 establishes the gas flow conditions and chamber pressure required for the specific plasma chemistry needed for the semiconductor process, whether for etching, deposition, or surface treatment applications.

[0098] The system positions at step 804 an impedance matching stub to increase ignition success rate. This mechanical or electronic tuning element is adjusted in a step 906 to optimize the impedance match between the magnetron source and the plasma load, ensuring maximum power transfer efficiency during the critical plasma ignition phase.

[0099] The magnetron microwave system is turned on at step 808 at the predetermined ignition condition power level. This power level is typically optimized for reliable plasma ignition rather than steady-state operation, as the impedance characteristics of the gas-filled chamber differ significantly from those of an established plasma.

[0100] The solid state source is activated at step 810 to achieve injection locking of the magnetron, maximizing ignition success rate through precise frequency control. The injectionlocking provides the narrow spectrum generation and frequency stability necessary for reliable plasma ignition, eliminating the frequency drift and mode hopping that can prevent successful plasma startup.

[0101] The system continuously monitors the plasma state at step 812 using plasma monitoring sensors to determine whether ignition has been successful. This monitoring may include optical emission detection, impedance measurements, or other plasma diagnostic techniques to verify plasma presence and stability.

[0102] A decision point determines whether the plasma is successfully ignited. If plasma ignition is confirmed (Yes path), the system proceeds at step 814 to steady-state operation. If no plasma is detected (No path), the system enters a troubleshooting sequence at step 816.

[0103] Upon successful ignition, the system transitions to steady-state operating conditions by adjusting power level, injection frequency, and stub position to achieve the desired process quality. These steady-state parameters are optimized for plasma uniformity, chemistry, and process performance rather than ignition reliability.

[0104] The system evaluates at step 818 whether pulsed plasma operation is required. If pulsing is enabled (True), the system waits for the programmed "on" time (Ton) before proceeding to the plasma termination phase.

[0105] When pulsed operation is active, the microwave power is turned off and the system waits for the programmed "off1time (Toff). This pulsed operation is common in processes like atomic layer deposition where precise timing of plasma exposure is critical.

[0106] After the off-time period, the system returns to the stub positioning step to prepare for the next ignition cycle, creating a continuous loop for pulsed plasma operation.

[0107] If plasma ignition fails (No path) from plasma monitoring, the system attempts recovery by changing the solid state source frequency and adjusting the stub position. These parameter adjustments address potential impedance mismatches or frequency-related ignition issues.

[0108] After making frequency and impedance adjustments, the system returns to the plasma state monitoring step 812 to attempt ignition again, creating a feedback loop that continues until successful ignition is achieved or predetermined retry limits are reached.

[0109] The flowchart 800 represents a comprehensive control algorithm that addresses the critical challenges of remote plasma generation, including reliable ignition, stable operation, and precise process control through the integration of injection locked magnetron technology with advanced process monitoring and feedback control systems.

[0110] FIG. 9 illustrates an in-situ plasma generation system 900 that utilizes injection locked magnetron technology to create plasma directly within the process chamber, above or adjacent to the semiconductor substrate being processed. This configuration represents a fundamental departure from remote plasma systems by generating the plasma at the point of application, enabling more direct control over plasma-substrate interactions and eliminating the complexities associated with radical transport and species lifetime limitations inherent in remote plasma configurations.

[0111] The system architecture centers around an injection locked magnetron 910 that receives frequency stabilization through an injection point 904 connected via a transmission line coaxial cable 921 to a solid state source for injection locking 920. This injection locking mechanism provides the narrow spectrum generation and frequency stability essential for reliable plasma ignition and sustained operation directly within the process environment. The solid state source 920 delivers a precisely controlled, low-power injection signal that locks the high-power magnetron to a specific frequency, eliminating the mode hopping and frequency drift that can cause plasma instability and process variations in conventional magnetron systems.

[0112] The microwave energy from the injection locked magnetron 910 is delivered through an output antenna 909 directly into the in-situ plasma applicator 922, where plasma generation occurs in immediate proximity to the semiconductor wafer or substrate being processed. This direct plasma generation approach maximizes the utilization of reactive species and minimizes losses associated with transport, making it particularly advantageous for processes requiring high radical flux or short-lived reactive species. The in-situ configuration also enables real-time optimization of plasma conditions based on substrate response, as the plasma-substrate interaction occurs within the same controlled environment.

[0113] Process gases are introduced through the gas flow inlet 924, where they are immediately dissociated and ionized by the microwave energy within the plasma applicator 922. This direct gas injection into the plasma generation zone ensures optimal utilization of process gases and enables precise control over plasma chemistry and radical generation rates. The plasma monitoring sensors 923 provide continuous feedback on plasma conditions, including parameters such as plasma density, optical emission characteristics, and impedance variations that indicate plasma stability and chemistry. This real-time monitoring capability is crucial for maintaining consistent process conditions and enabling rapid response to process variations or disturbances.

[0114] The injection locked magnetron technology offers significant advantages for in-situ plasma applications, particularly in terms of plasma ignition reliability and frequency tuning capabilities. The system can rapidly transition between different operating conditions optimized for plasma ignition versus steady-state operation, addressing the fundamental challenge that ignition conditions often differ from optimal processing conditions. The frequency injection approach enables millisecond-scale adjustments to plasma conditions, making the system particularly suitable for advanced processes such as plasma-enhanced atomic layer deposition where precise timing and rapid transitions between plasma-on and plasma-off states are essential for achieving the desired film properties and process control.

[0115] FIG. 10 illustrates a flowchart for in-situ plasma generation by a system that utilizes injection locked magnetron technology to create plasma directly within the process chamber, above or adjacent to an semiconductor substrate being processed. This sequence of steps represents a fundamental departure from the sequence of steps practiced by remote plasma systems, by generating the plasma at the point of application, enabling more direct control over plasma-substrate interactions and eliminating the complexities associated with radical transport and species lifetime limitations inherent in remote plasma configurations.

[0116] Generally, in-situ plasma generation involves the injection locking process for magnetron stabilization, plasma ignition and steady-state operation transitions, real-time monitoring and feedback control, frequency and phase adjustments for optimal plasma conditions, with the specific advantages of in-situ plasma generation.

[0117] The flow chart 1000 is initiated with step 1010 of process parameter initialization. Process parameter initialization consists of setting the pressure and flow setpoints for the desired chemistry in the in-situ plasma chamber. This critical first step establishes the gas environment within the plasma applicator, determining the base pressure and gas flow rates required for the specific semiconductor process. Unlike remote plasma systems where gas residence time and transport effects must be considered, the in-situ configuration allows for direct optimization of gas conditions at the point of plasma generation, enabling precise control over plasma chemistry and radical production rates.

[0118] The subsequent step 1020, concerning impedance matching optimization involves the system positioning the impedance matching stub to increase ignition success rate by optimizing the coupling between the magnetron source and the plasma load. This tuning step is particularly important for in-situ plasma systems because the impedance characteristics of the gas-filled chamber differ significantly from those encountered after plasma ignition. Thestub positioning accounts for the initial gas load conditions and prepares the system for the impedance transition that occurs during plasma ignition.

[0119] The subsequent step 1030, concerning magnetron system activation involves activating the magnetron microwave system at the predetermined ignition condition power level. This power setting is specifically optimized for reliable plasma ignition rather than steady-state operation, as the power requirements for breaking down the process gases and initiating plasma formation typically differ from those needed for sustained plasma operation. The injection locked magnetron provides the high-power microwave energy necessary to overcome the ignition threshold while maintaining frequency stability.

[0120] Thereafter, at step 1040, injection locking engagement takes place. Specifically, the solid state source is turned on to achieve injection locking of the magnetron, maximizing ignition success rate through precise frequency control. The injection locking mechanism provides the narrow spectrum generation that eliminates frequency drift and mode hopping, ensuring consistent ignition conditions. This frequency stabilization is crucial for in-situ plasma applications where reliable ignition directly impacts process repeatability and substrate uniformity.

[0121] Further, at step 1050 the plasma state is monitored. The system continuously monitors the plasma state using integrated plasma monitoring sensors to determine ignition success. These sensors may include optical emission detectors, impedance measurement systems, or other diagnostic tools that provide real-time feedback on plasma presence and characteristics. The monitoring system must distinguish between successful plasma ignition and unstable or partial ignition conditions that could lead to process variations.

[0122] Further yet, at step 1060, the system leverages an ignition success decision point. A critical decision point evaluates whether plasma ignition has been successfully achieved. If the monitoring sensors confirm stable plasma formation (Yes path), the system proceeds to steady-state operation optimization, in step 1070. This decision point incorporates multiple plasma parameters to ensure that ignition is not only achieved but also stable enough to support the subsequent processing steps.

[0123] Upon successful ignition confirmation in step 1070, the system transitions in step 1180 to steady-state operating conditions by adjusting power level, injection frequency, and stub position to achieve the desired process quality. These steady-state parameters are optimized for plasma uniformity, chemistry control, and process performance rather than ignition reliability. The transition may involve reducing power levels, fine-tuning frequency for optimal plasma density, and adjusting impedance matching for maximum efficiency.

[0124] In step 1080 the system performs pulsed operation control. The system evaluates whether pulsed plasma operation is required for the specific process. If pulsing is enabled (True), the system waits for the programmed plasma-on time (Ton) before proceeding to the plasma termination phase. This pulsed operation capability is essential for processes like plasma-enhanced atomic layer deposition where precise timing of plasma exposure controls film growth and properties.

[0125] In step 1090 the system contemplates plasma termination. When the programmed on-time expires or continuous operation is complete, the microwave power is turned off to terminate the plasma. The injection locked magnetron system enables rapid plasma extinction with precise timing control, which is particularly important for pulsed processes where the plasma-off time is as critical as the plasma-on time for achieving desired process outcomes.

[0126] If plasma ignition fails (No path) from the monitoring decision point, the system enters a recovery sequence at step 1092 by changing the solid state source frequency and adjusting the stub position. These parameter modifications address potential causes of ignition failure, including impedance mismatches, frequency-related coupling issues, or changes in gas conditions that may have occurred since the initial setup.

[0127] After implementing the frequency and impedance adjustments, the system returns to the plasma state monitoring step to attempt ignition again. This creates a feedback loop that continues until successful ignition is achieved or predetermined retry limits are reached, ensuring robust operation even under varying process conditions or equipment drift scenarios.

[0128] This comprehensive control methodology 1000 leverages the advantages of injection locked magnetron technology to provide reliable, repeatable in-situ plasma generation with the flexibility to accommodate both continuous and pulsed operation modes essential for advanced semiconductor processing applications.

[0129] Multi-antenna plasma systems represent a challenging but potentially advantageous approach to plasma generation that utilizes multiple microwave sources driving a common plasma simultaneously. The concept involves deploying several injection-locked magnetron systems, each with its own antenna, all converging into the same process chamber to create and control a shared plasma environment.

[0130] The multi-antenna approach requires multiple instances of the dual circulator setup from the base invention, with a plurality of circulators each connected to a corresponding magnetron and solid-state generator. Each magnetron system has its own dedicated antenna injection port, comprising the built-in antenna of the corresponding magnetron, positioned within the process chamber rather than combining magnetrons in a single waveguide. Thisconfiguration necessitates independent impedance matching for each channel, as each antenna injection port presents different load conditions to its respective magnetron source. The system requires precise synchronization of all magnetron sources through a common phase controller or signal drive to maintain coherent operation across the plurality of injection-locked magnetrons. This component responsible for the synchronization may be one of a low power multisource microwave generator with the ability to sweep the output frequency along the whole allowed band. The different sources are phase controlled and their output phase can be changed in the [0°, 360°] range.

[0131] A significant technical challenge identified is the cross-coupling between multiple antenna injection ports operating in the same plasma environment. Unlike solid-state sources that can be more easily controlled, magnetron-based systems experience complex interactions when multiple sources drive a common plasma load. These cross-coupling effects have historically made multi-antenna plasma systems difficult to implement successfully, as changes in one channel can affect the impedance and operating conditions of all other channels in the plurality of injection-locked magnetrons.

[0132] Despite the technical challenges, multi-antenna plasma systems offer potential advantages for large-area processing and improved plasma uniformity. The ability to independently control multiple sources could enable better plasma distribution across large substrates and provide redundancy for critical processes. The phase control capabilities of injection-locked magnetrons could potentially overcome some of the traditional cross-coupling limitations by providing more precise control over the electromagnetic field distribution within the plasma chamber.

[0133] Successful implementation of multi-antenna plasma systems requires sophisticated control algorithms that can manage the interactions between sources, a plurality of impedance matching networks each connected to a corresponding magnetron, and a plasma monitoring system configured to provide real-time feedback for optimization of the plurality of injection-locked magnetrons. The injection-locking technology provides the frequency stability and phase control necessary to make such systems viable, though significant engineering challenges remain in managing the complex electromagnetic interactions within the plasma environment.

[0134] FIG. 5 illustrates an injection locking technology arrangement that may be used to implement multi-antenna plasma systems. More specifically, FIG. 5 illustrates an arrangement of multiple magnetrons.

[0135] FIG. 11 illustrates the flowchart 1100 for plasma generation using multi-antenna plasma systems.

[0136] The flowchart comprises a step 1102, concerning process parameter initialization, comprising setting the pressure and flow setpoints for the desired chemistry in the plasma chamber. This foundational step establishes the gas environment and pressure conditions required for the specific plasma process, taking into account the complexities of multi-antenna operation where gas distribution and residence time must be optimized for multiple plasma generation points within the same chamber.

[0137] At step 1104, multi-channel impedance matching is performed. The system positions multiple impedance matching stubs for maximum ignition success rate across all antenna channels. Unlike single-antenna systems, this step requires coordinated tuning of multiple independent matching networks, as each antenna in the array presents different load conditions and coupling characteristics. The stub positioning must account for the electromagnetic interactions between antennas and optimize the overall system for reliable multi-point plasma ignition. The stub positions for multiple antennas may be coordinated either sequentially or simultaneously.

[0138] At step 1106, magnetron array activation is performed. All magnetron microwave systems in the array are turned on simultaneously at their respective ignition condition power levels. This coordinated activation ensures that all sources are available for plasma generation while maintaining the power settings optimized for ignition rather than steady-state operation. The multi -magnetron approach provides the distributed power necessary for large-area plasma coverage and uniform ignition across the entire chamber.

[0139] At step 1108, synchronized injection locking is performed. The solid state sources for all magnetrons are activated to achieve injection locking and maximize ignition success rate through precise control of frequencies and phases across the entire array. This critical step enables coherent operation of the multi-antenna system by synchronizing all magnetron sources to specific frequency and phase relationships that minimize destructive interference and optimize constructive coupling for plasma generation.

[0140] At step 1110, an assessment about plasma ignition is performed. The system evaluates whether plasma ignition has been successfully achieved across the multi-antenna array. This decision point must assess not only the presence of plasma but also its distribution and uniformity across all antenna regions, as partial ignition or non-uniform plasma formation can lead to process variations and substrate damage in multi-antenna configurations.

[0141] At step 1112, continuous plasma monitoring is performed. Upon successful ignition, the system continuously monitors plasma state using multiple sensors distributed throughout the chamber. This monitoring capability is essential for multi-antenna systems where plasma conditions can vary spatially across the chamber, requiring real-time feedback to maintain uniform plasma characteristics and detect any localized instabilities or extinctions.

[0142] At step 1114, dynamic plasma optimization is performed. The system actively adjusts the solid state source frequencies and phases to achieve desired plasma parameters and distribution across the chamber. This dynamic control capability represents a key advantage of the multi-antenna approach, enabling real-time optimization of plasma uniformity, density distribution, and chemistry through coordinated adjustment of multiple injection-locked magnetron sources.

[0143] If plasma ignition fails, at step 1116, a multi-parameter recovery protocol is performed. If plasma ignition fails, the system implements a comprehensive recovery protocol by simultaneously adjusting solid state source frequencies, phases, and stub positions across all channels. This multi-parameter optimization addresses the complex interdependencies in multi-antenna systems where the failure of one channel can affect the performance of all other channels due to cross-coupling effects.

[0144] After implementing the multi-parameter adjustments, the system performs the step 1118, a recovery loop return, by returning to the plasma ignition assessment step to re-evaluate ignition success. This creates a feedback loop that continues until successful plasma ignition is achieved across all antenna channels or predetermined retry limits are reached, ensuring robust operation despite the increased complexity of managing multiple synchronized magnetron sources.

[0145] The flowchart represents a sophisticated control algorithm specifically designed to address the unique challenges of multi-antenna plasma systems, including cross-coupling between sources, impedance matching complexities, and the need for coordinated control of multiple injection-locked magnetrons. The integration of frequency and phase control across multiple channels enables the system to overcome traditional limitations of multi-source plasma generation while providing the uniformity and control advantages that justify the increased system complexity.

[0146] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

CLAIMS1. An apparatus, comprising:a magnetron configured to generate microwave power, the magnetron including a built-in antenna;a solid-state generator configured to generate a reference signal;at least one circulator connected to the magnetron and the solid-state generator via a plurality of waveguides, the circulator configured to direct the reference signal from the solid-state generator to the magnetron; andan antenna injection port comprising the built-in antenna of the magnetron, the antenna injection port configured to receive the reference signal,wherein the reference signal injection-locks the magnetron such that a frequency of the microwave power generated by the magnetron is synchronized with a frequency of the reference signal.

2. The apparatus of claim 1, wherein the solid-state generator is configured to generate the reference signal at a frequency within ±5 MHz of a natural frequency of the magnetron.

3. The apparatus of claim 1, further comprising a power supply unit configured to provide power to the magnetron and the solid-state generator.

4. The apparatus of claim 1, wherein the at least one circulator is configured to protect the magnetron from reflected power.

5. The apparatus of claim 1, wherein the at least one circulator comprises a first circulator and a second circulator, the first circulator connected to the magnetron and configured to direct microwave power to a process load, the second circulator connected between the solid-state generator and the first circulator and configured to protect the solid-state generator from reflected power.

6. The apparatus of claim 1, further comprising a process load, wherein the plurality of waveguides are further configured to direct the microwave power from the magnetron to the process load.

7. The apparatus of claim 6, wherein the process load is configured for plastic preform heating in a bottle manufacturing process.

8. The apparatus of claim 1, wherein the solid-state generator is configured to generate the reference signal at a power level at least three orders of magnitude lower than the microwave power generated by the magnetron.

9. A method of operating a microwave generator, comprising:generating a reference signal using a solid-state generator;directing the reference signal to a magnetron using at least one circulator;injecting the reference signal into the magnetron through an antenna injection port comprising a built-in antenna of the magnetron; andinjection-locking the magnetron with the reference signal such that a frequency of microwave power generated by the magnetron is synchronized with a frequency of the reference signal.

10. The method of claim 9, wherein generating the reference signal comprises generating the reference signal at a frequency within ±5 MHz of a natural frequency of the magnetron.

11. The method of claim 9, further comprising directing the microwave power from the magnetron to a process load via the at least one circulator and waveguides.

12. The method of claim 11, wherein the process load is configured for plastic preform heating in a bottle manufacturing process.

13. The method of claim 9, wherein generating the reference signal comprises generating the reference signal at a power level at least three orders of magnitude lower than the microwave power generated by the magnetron.

14. The method of claim 9, further comprising protecting the magnetron from reflected power using the at least one circulator.

15. The method of claim 9, wherein the at least one circulator comprises a first circulator connected to the magnetron and a second circulator connected between the solid-state generator and the first circulator, the method further comprising:directing reflected power from the magnetron through the first circulator to the second circulator; andprotecting the solid-state generator by directing the reflected power from the second circulator to a water load.

16. The method of claim 15, wherein the at least one circulator comprises a first circulator and a second circulator, the method further comprising absorbing reflected power using a water load connected to the second circulator.

17. An apparatus, comprising:a magnetron configured to generate microwave power, the magnetron including a built-in antenna;a solid-state generator configured to generate a reference signal;a first circulator connected to the magnetron and configured to direct microwave power from the magnetron to a process load and to direct the reference signal to the magnetron;a second circulator connected to the solid-state generator and the first circulator, the second circulator configured to direct the reference signal from the solid-state generator to the first circulator;an antenna injection port comprising the built-in antenna of the magnetron configured to receive the reference signal from the solid-state generator via the second circulator and the first circulator;waveguides connected to the first circulator and configured to direct the microwave power from the magnetron to a process load; anda water load connected to the second circulator and configured to absorb reflected power to protect the solid-state generator,wherein the reference signal injection-locks the magnetron such that a frequency of the microwave power generated by the magnetron is synchronized with a frequency of the reference signal.

18. The apparatus of claim 17, wherein the solid-state generator is configured to generate the reference signal at a frequency within ±5 MHz of a natural frequency of the magnetron.

19. The apparatus of claim 17, wherein the solid-state generator is configured to generate the reference signal at a power level at least three orders of magnitude lower than the microwave power generated by the magnetron.

20. The apparatus of claim 17, wherein the process load comprises a plasma chamber.

21. The apparatus of claim 17, wherein the second circulator provides isolation between reflected power from the process load and the solid-state generator.

22. An apparatus for plasma generation, comprising:a plurality of injection-locked magnetrons, each magnetron configured to generate microwave power and including a built-in antenna;a plurality of solid-state generators, each solid-state generator configured to generate a reference signal for injection locking a corresponding magnetron;a plurality of circulators, each circulator connected to a corresponding magnetron and solid-state generator and configured to direct the reference signal to the corresponding magnetron; a plurality of antenna injection ports, each antenna injection port comprising an output antenna of a corresponding magnetron and positioned within a plasma chamber;a plurality of impedance matching networks, each impedance matching network connected to a corresponding magnetron and configured to optimize coupling between the magnetron and a plasma load;a control system configured to synchronize frequencies and phases of the plurality of solid-state generators to enable coherent operation of the plurality of injection-locked magnetrons; anda plasma monitoring system configured to provide real-time feedback on plasma conditions within the plasma chamber,wherein the plurality of injection-locked magnetrons are configured to generate plasma simultaneously at multiple points within the plasma chamber.

23. The apparatus of claim 22, wherein the control system is configured to:position the plurality of impedance matching networks to optimize ignition success rate across all antenna channels;activate the plurality of injection-locked magnetrons simultaneously at respective ignition condition power levels;activate the plurality of solid-state generators to achieve synchronized injection locking across the multi-antenna array;evaluate plasma ignition success across the plurality of antennas;continuously monitor plasma state using the plasma monitoring system; anddynamically adjust frequencies and phases of the plurality of solid-state generators to optimize plasma parameters and distribution across the plasma chamber.

24. The apparatus of claim 22, wherein each of the plurality of circulators comprises a first circulator and a second circulator, the second circulator connected to a water load configured to absorb reflected power.

25. The apparatus of claim 22, wherein the plasma chamber is a wafer annealing applicator configured for heating semiconductor wafers.

26. The apparatus of claim 25, wherein the plurality of injection-locked magnetrons are configured to achieve uniform heating across a 300mm semiconductor wafer.

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