A control circuit, control method, and generation method for plasma generation

Abstract

This invention relates to a control circuit, control method, and generation method for plasma. Based on the laws of gas discharge, it utilizes the existing voltage and current detectors in the sputtering coating power supply to generate the plasma required for the sputtering coating process without adding additional components. Plasma generation is determined when the output current and power exceed set current and power thresholds, respectively, with high accuracy. This avoids misjudgments due to localized arc discharge in small areas of the target material during the ignition stage, ensuring the normal operation of ignition, target cleaning, and sputtering coating processes. If the number of consecutive ignition failures exceeds a failure threshold, the ignition circuit can be shut down, and an error message can be sent to the user to modify relevant process parameters and optimize the process. In the event of a sudden situation during normal sputtering coating that causes plasma extinguishing, the ignition circuit is automatically restarted, rapidly restoring plasma generation to the sputtering coating conditions before extinguishing the plasma, ensuring coating quality.

Description

Technical Field

[0001] This invention relates to the field of control circuits and methods for plasma generation, and particularly to a control circuit, control method, and generation method for plasma generation. Background Technology

[0002] The three most common states of matter are solid, liquid, and gas. In addition, matter possesses a special state: plasma. Plasma is an aggregate of electrically neutral particles, cations, and electrons. It may exhibit localized positive or negative charges, and its internal particle distribution is uneven, but overall, plasma is electrically neutral. Plasma is filled with a large number of moving charged particles, generating a changing magnetic field. This changing magnetic field, in turn, affects the movement of the charged particles. Under this complex electromagnetic interaction, the internal state of plasma is extremely complex, resulting in highly complex and unique properties. It is precisely because of these unique properties that plasma is widely used in scientific research and industrial production, playing a vital role in these fields.

[0003] Given the urgent need for plasma in scientific research and production, generating stable plasma has become a key research area. Plasma is typically generated under high temperature, high pressure, or high-frequency electric field conditions. In the semiconductor field, due to limitations such as the performance of semiconductor materials, high-pressure or high-frequency electric field methods are generally used to generate plasma. In sputtering coating equipment, the coating process can usually be divided into two steps: generating plasma and using plasma.

[0004] The first step is the ignition stage, which generates plasma: a high voltage is generated between two electrodes in the sputtering chamber using a sputtering power supply. The specific voltage value depends on the actual process; the high voltage range for common processes is approximately 800V to 1200V, while the ignition voltage for special applications can reach over 1500V. Figure 1 The figure shows the voltage-current characteristic curve of gas discharge. When a voltage is initially applied within the sputtering chamber, the conductivity of the rarefied gas inside the chamber is very low, the equivalent resistance is very high, and the power supply output current is very small. The gas inside the sputtering chamber is in the dark discharge region of stage ab, where the current density is very low, approximately 10-1. -15 A / cm 2 Within this range. As the voltage gradually rises to a certain value, the discharge enters the Townsend discharge region of the cd stage, where the current density is approximately 10. -13 A / cm 2 ~10 -5 A / cm 2 As the voltage increases further, the discharge enters the normal glow discharge region of the ef stage, plasma begins to be generated, the equivalent resistance of the sputtering chamber decreases, the power supply output current increases, and the current density gradually rises to approximately 10. -4 A / cm2 ~10 -2 A / cm 2 The voltage drops. However, because the current of normal glow discharge is not large enough, the plasma density generated is not high enough, resulting in a very low yield for sputtering coating. Therefore, sputtering coating generally does not operate in the normal glow discharge region. As the voltage further increases, the discharge enters the anomalous glow discharge region of the fg stage, where the current density is approximately 10. -1 A / cm 2 Around 10⁻⁶, the plasma density is very high, and sputtering deposition typically operates in this region. If the discharge deepens further into the arc discharge region of the gh stage, the current density rises to 10⁻⁶. 0 A / cm 2 As mentioned above, the intense discharge in this region can severely ablate the target material and contaminate the substrate, making sputtering deposition impossible. Therefore, entering the arc discharge region should be avoided. The ignition phase lasts for a very short time, but the sputtering power supply output needs to be much higher than the operating voltage during normal sputtering deposition. This is necessary to allow the gas discharge to enter the anomalous glow discharge region and generate plasma of sufficient density to ensure the normal operation of the sputtering deposition process.

[0005] The second step is the sputtering coating stage, which uses plasma: After determining that plasma is generated, the output voltage of the sputtering coating power supply is generally between 300V and 800V, depending on the specific process, and should be kept as constant as possible to ensure that the sputtering coating process can proceed smoothly and obtain a high-quality film.

[0006] Currently, there are two main methods for determining plasma generation: spectroscopic methods and current methods. Spectroscopic methods determine plasma generation by detecting the light signal emitted by the plasma. For example, the invention patent "Method for Detecting Plasma Ignition State" (publication date: February 4, 2015, publication number CN102507003B) describes that before plasma is generated, the optical detection probe in the sputtering chamber cannot detect a spectral signal or the detected spectral signal intensity is low. After plasma is generated, when the spectral intensity gradually rises to a set threshold, it can be determined that the plasma ignition has been successful. Figure 1As shown, the spectral signals in the dark discharge region and the Townsend discharge region are weak, while the spectral signals in the normal glow discharge region, the anomalous glow discharge region, and the arc discharge region are strong. Spectroscopic methods that utilize the differences in spectral signal intensity between different discharge regions to determine plasma generation are feasible, but they have several drawbacks. First, a separate spectral detection probe needs to be installed within the sputtering chamber, affecting the spatial distribution of the plasma and interfering with the sputtering process. Second, the electromagnetic environment within the sputtering chamber is complex, and the chamber contains corrosive gases and other chemicals required for the process, placing high demands on the insulation, corrosion resistance, and airtightness of the spectral detection probe, resulting in high costs. Third, for optical detection probes, the intensity of the received light is related to factors such as the probe's position and angle relative to the light source; these factors can cause differences in spectral signals even when the probe detects the same plasma. These unfavorable factors severely limit the application of spectral methods in sputtering coating power supplies.

[0007] The current method is based on Figure 1 The generation of plasma is determined by the different current densities corresponding to different discharge regions. For example, the invention patent "A Fast and Reliable Combustion-Assisting Circuit for a DC Magnetron Sputtering Power Supply" (publication date: September 3, 2019, publication number CN110198138A) describes this: when the output current of the DC magnetron sputtering power supply exceeds a set threshold during the ignition process, plasma generation is considered successful. The current method utilizes the current detection probe already present in the sputtering power supply, eliminating the need for additional components. However, the current method has a high false alarm rate, leading to errors in the working logic of the sputtering power supply and affecting the normal progress of the process. As mentioned earlier, plasma is filled with a large number of moving neutral and charged particles, therefore, the plasma is not uniform. During ignition, especially in the initial ignition stage when the target is first installed, due to insufficient surface cleanliness, the target generally needs to be cleaned. Localized micro-areas on the target surface contaminated with pollutants generate arc discharges that burn off the contaminants. At this time, the output current increases to exceed the threshold of the current method. However, because only a small, localized area generates arc discharge while no plasma is produced in other areas, the current method misinterprets this as plasma generation. Consequently, the sputtering power supply stops target cleaning and begins subsequent processes. This misinterpretation by the current method severely interferes with the target cleaning process, and uncleaned targets also negatively impact subsequent sputtering coating processes. Summary of the Invention

[0008] The technical problem this invention aims to solve is that the spectroscopic method requires the installation of a separate spectral detection probe within the sputtering chamber, which affects the spatial distribution of plasma and interferes with the sputtering process. The electromagnetic environment within the sputtering chamber is complex, and it contains corrosive gases and other chemicals required for the process, placing high demands on the insulation, corrosion resistance, and airtightness of the spectral detection probe, resulting in high costs. Thirdly, for optical detection probes, the intensity of the received light is related to factors such as the probe's position and angle relative to the light source. These factors can cause different spectral signals even when the probe detects the same plasma. The current-based method has a high false alarm rate. During target cleaning, a small, localized area on the target surface contaminated with pollutants may generate an arc discharge that burns the pollutants. At this point, the output current increases to exceed the current-based method's judgment threshold. However, because only a small, localized area generates an arc discharge, while other areas do not generate plasma, the current-based method misjudges this as plasma generation. The sputtering power supply then stops target cleaning and begins subsequent processes. The misjudgment by the current-based method severely interferes with the target cleaning process, and an uncleaned target will also adversely affect subsequent sputtering coating processes. To address the aforementioned deficiencies in the prior art, a control circuit, control method, and generation method for plasma generation are provided.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0010] A control circuit for plasma generation is constructed, including an input rectifier and filter circuit, an ignition circuit, an output filter circuit, a DSP circuit, and an input circuit.

[0011] The input rectifier and filter circuit is used to connect to the input AC power, rectify the AC power into DC power, and then filter the DC power.

[0012] The ignition circuit is connected to the input rectifier and filter circuit, and raises the filtered voltage to the set value.

[0013] The output filter circuit, connected to the ignition circuit, filters the voltage that has risen to a set value before outputting it to the chamber load.

[0014] The DSP circuit is connected to the output filter circuit and the ignition circuit, and obtains the real-time current value and real-time voltage value output by the output filter circuit, and calculates the real-time power value from the obtained real-time current value and real-time voltage value.

[0015] The input circuit, electrically connected to the DSP circuit, is used to input the set current threshold and power threshold.

[0016] The DSP circuit compares the real-time current value with the set current threshold and the real-time power value with the set power threshold, and controls the working mode of the ignition circuit based on the comparison results.

[0017] Preferably, the ignition circuit includes a functional circuit and a power circuit. The functional circuit generates an ignition high voltage, the power circuit provides input power to the chamber load, and the DSP circuit compares the real-time current value and real-time power value with the set current threshold and power threshold to control the start and stop of the functional circuit.

[0018] Preferably, when the real-time current value is greater than a set current threshold and the real-time power value is greater than a set power threshold, the DSP circuit control function circuit is turned off.

[0019] If the real-time current value is less than the set current threshold or the real-time power is less than the set power threshold, the DSP circuit control function circuit remains on.

[0020] Preferably, the input rectifier and filter circuit includes a rectifier circuit and a filter circuit. The rectifier circuit consists of multiple sets of diodes, which are connected to the three-phase input AC power and rectify it into DC power. The ignition circuit consists of a driver circuit and a MOSFET. The output filter circuit consists of multiple sets of diodes and is connected to a voltage detection circuit and a current detection circuit. The voltage detection circuit and the current detection circuit acquire real-time voltage and current values.

[0021] The control circuit is also equipped with a multiplier to calculate the real-time power. The current detection circuit and voltage detection circuit are connected to the DSP circuit through a comparator and an AND gate. The comparator compares the real-time current with a set current threshold and the real-time power with a set power threshold. The AND gate sends the comparison results to the DSP, which then controls the ignition circuit to turn on or off.

[0022] A plasma generation control method is constructed, which involves connecting an input AC power supply and setting current and power thresholds. The AC power supply is rectified into DC power and then filtered. The filtered voltage is then increased to the set value, and the increased voltage is output filtered and sent to the chamber load. The real-time output voltage and current values ​​to the chamber load are obtained, and the power value is calculated. The real-time output power and current values ​​are compared with the set power and current thresholds, and the voltage increase is controlled to be turned on or off based on the comparison results.

[0023] Preferably, the process of raising the filtered voltage to the set value includes:

[0024] The functional voltage that boosts the voltage and the power voltage that keeps the chamber load operating;

[0025] The process of comparing the real-time output power value and the real-time output current value with the set power threshold and the set current threshold, and controlling the opening and closing of the ignition circuit according to the comparison result, also includes:

[0026] If the real-time output current value is greater than the set current threshold and the real-time output power value is greater than the set power threshold, the function of increasing the voltage will be turned off.

[0027] If the real-time output current value is less than the set current threshold or the real-time output power is less than the set power threshold, the function voltage of increasing the voltage will be turned on.

[0028] A method for generating plasma is constructed, the method comprising the following steps:

[0029] Start the ignition circuit and set the circuit parameter thresholds;

[0030] Obtain the real-time output voltage and real-time output current of the ignition circuit, and calculate the real-time output power;

[0031] The acquired real-time output current and calculated real-time output power are compared with the set parameter thresholds.

[0032] The plasma generation status is determined based on the comparison results. If the plasma generation is successful, the ignition circuit is shut down to perform the second-stage sputtering coating process. If the plasma generation fails, the ignition circuit is restarted and the plasma generation status is reassessed until the plasma generation is successful.

[0033] Preferably, the set parameter thresholds include a set current threshold and a set power threshold;

[0034] The process of determining the plasma generation status based on the comparison results includes:

[0035] The real-time output current and calculated real-time output power are compared with the set parameter thresholds. If the real-time output current is greater than the set current threshold and the calculated real-time output power is greater than the set power threshold, the plasma generation is determined to be successful, the ignition circuit is turned off to carry out the second-stage sputtering coating process, and the number of ignition failures is set to 0.

[0036] If the acquired real-time output current is less than the set current threshold, or the calculated real-time output power is less than the set power threshold, plasma generation is determined to have failed. The number of failed ignition attempts is incremented by 1, and the ignition circuit is restarted until the acquired real-time output current is greater than the set current threshold and the calculated real-time output power is greater than the set power threshold. Then, plasma generation is determined to have succeeded.

[0037] Preferably, the set parameter threshold also includes a threshold for the number of ignition failures;

[0038] The process of determining plasma generation failure, incrementing the count of ignition failures by 1, and restarting the ignition circuit when the acquired real-time output current is less than the set current threshold or the calculated real-time output power is less than the set power threshold, also includes:

[0039] If the cumulative number of ignition failures does not exceed the threshold, the ignition circuit continues to work until the plasma generation is determined to be successful and the second-stage sputtering coating process is carried out. After success, the number of ignition failures is reset to 0.

[0040] If the cumulative number of ignition failures exceeds the threshold, the ignition circuit will be shut down and the system will be alerted with an error message.

[0041] Preferably, the parameter threshold includes a threshold for the number of ignition failures;

[0042] The process of determining the plasma generation status based on the comparison results, and if the plasma generation is successful, or restarting the ignition circuit and re-determining the plasma generation status, until the plasma generation is successful, also includes:

[0043] The system monitors the output current and output voltage in real time and calculates the real-time output power. If the real-time output current is less than the set current threshold and the real-time output power is less than the set power threshold, the plasma will be extinguished and the ignition circuit will be restarted until the plasma is successfully generated. If the plasma is extinguished, the number of ignition failures will be accumulated. If the accumulated number of ignition failures is greater than the ignition failure threshold, the system will report an error and shut down, and ignition will not be possible again.

[0044] The beneficial effects of this invention are as follows: Based on the gas discharge law, and utilizing the existing voltage and current detectors in the sputtering coating power supply, the plasma required for the sputtering coating process can be generated without adding additional components, thus providing an accurate method for determining plasma generation. This invention determines plasma generation when the output current I and output power P exceed set current thresholds It and power thresholds Pt, respectively, with high accuracy. It avoids misjudgments due to localized arc discharge in small areas of the target material during the ignition stage, ensuring the normal operation of ignition, target cleaning, and sputtering coating processes. When the number of consecutive ignition failures N exceeds the failure threshold Nt, the ignition circuit can be shut down, and the system will notify the user to change relevant process parameters and optimize the process. In the event of plasma extinction due to sudden events such as arcing during normal sputtering coating, this invention can automatically restart the ignition circuit, rapidly regenerating plasma and quickly restoring the sputtering coating conditions before plasma extinction, ensuring coating quality. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0046] Figure 1 This is a gas discharge voltage-current characteristic curve of a preferred embodiment of the present invention;

[0047] Figure 2 This is a schematic block diagram of the control circuit of a preferred embodiment of the present invention;

[0048] Figure 3 Another block diagram of the control circuit of a preferred embodiment of the present invention;

[0049] Figure 4 A detailed circuit diagram of the control circuit of a preferred embodiment of the present invention;

[0050] Figure 5 This is a flowchart of a plasma generation method according to a preferred embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of the plasma generation method according to a preferred embodiment of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0053] A preferred embodiment of the present invention provides a control circuit and control method for plasma generation; such as Figure 2-3As shown, the control circuit includes an input power supply 11, an input rectifier and filter circuit 12, an ignition circuit 13, and an output filter circuit 15. The input power supply 11, after being connected to a three-phase 380V AC mains power supply, is rectified into DC power by the input rectifier and filter circuit 12, and then filtered to obtain a better DC power. The DC power supplies the ignition circuit 13, and the output of the ignition circuit, after passing through the output filter circuit 15, is connected to the load in the sputtering chamber for ignition, target cleaning, and sputtering coating processes. The control circuit also includes a voltage detection circuit 16 and a current detection circuit 17 connected to the output filter circuit. The voltage detection circuit 16 detects the DC output voltage value, and the current detection circuit 17 detects the DC output current value, transmitting the detected voltage and current values ​​to the DSP circuit 20. Simultaneously, the detected voltage and current values ​​are multiplied by the multiplier 17 to obtain the DC output power, which is then transmitted to the DSP circuit. After AD sampling and DSP calculation by the DSP circuit, the adjustment signal for the ignition circuit is obtained, thereby adjusting the output of the ignition circuit. It also includes an input circuit 19, which sets relevant process parameters and displays the current operating status of the sputtering coating power supply, including the set current threshold, the set power threshold, and the threshold for the number of ignition failures. The output voltage and current values ​​are detected by voltage and current detection circuits and compared with the set current and power thresholds to control the ignition circuit, thereby controlling the chamber load.

[0054] Specifically, in the above scheme, such as Figure 2 As shown, the calculation of output power from the output current and output voltage is performed in the multiplier, or it can be performed within the DSP circuit. Furthermore, the comparison of output current and output power with the set circuit threshold and set power threshold can also be performed within the DSP circuit, thus simplifying the circuit. However, this method places a greater computational burden on the DSP circuit compared to the aforementioned scheme. The DSP circuit with the multiplier only needs to act directly based on the received AND gate signal without performing complex calculations, resulting in a faster response. It should be noted that in this invention, the term "ignition circuit" generally refers to a functional circuit capable of generating a high-voltage ignition, which can be a power circuit, another auxiliary ignition circuit, or a combination of both.

[0055] Furthermore, such as Figure 4As shown, the input rectifier and filter circuit 11 includes an input rectifier circuit and an input filter circuit. The rectifier circuit consists of six sets of diodes. Each line of the input three-phase AC power is connected through two sets of diodes in parallel. The other end of each diode is connected to a first filter inductor L1, and the two ends of the first filter inductor are connected to a first capacitor C1. The input filter circuit, composed of the first filter inductor L1 and the first capacitor C1, filters out the pulsating component of the DC power, resulting in a higher quality DC power. The ignition circuit 13 consists of four sets of drive circuits and MOSFETs. The source (S) of the lower MOSFET and the drain (D) of the upper MOSFET are connected to the two ends of the first capacitor C1, respectively. The gate (G) is connected to the drive circuit and then to the DSP circuit. Simultaneously, the source (S) terminals of two sets of MOSFETs are connected to both ends of the first transformer T1, and the other end is connected to the second transformer T2. The output current of the first transformer then passes through the output rectifier filter 15, which includes four sets of diodes D7, D8, D9, and D10. Each pair of diodes is connected to one output terminal of the transformer to form the output. The DC output current and voltage values ​​are obtained through current and voltage sensors and transmitted to the DSP circuit. At the same time, the multiplier calculates the DC output power value and transmits it to the control unit. Simultaneously, the set current threshold, set power threshold, and ignition failure count threshold are input through the operation / display panel. The real-time current and power values ​​are transmitted to the first comparator U1 and the second comparator U2 for comparison with the set thresholds, and the comparison result is output. Then, the level signal of the AND gate U3 determines whether plasma is generated.

[0056] Furthermore, such as Figure 4As shown, the relevant parameters for this operation are first determined based on the specific sputtering coating process. These parameters are input through the operation / display interface, including the set current threshold It, the set power threshold Pt, and the continuous ignition failure threshold Nt, which are used to determine the ignition conditions. After receiving the relevant input parameters, the DSP circuit transmits the set current threshold It and the set power threshold Pt to pin 2 of the first comparator U1 and pin 2 of the second comparator U2. Initially, the output of the sputtering coating power supply is 0, and the initial sampling results of the current sampling circuit and the voltage sampling circuit are both 0. Pin 3 of the first comparator U1 outputs a 0-level signal (Iflag=0), and pin 3 of the second comparator U2 outputs a 0-level signal (Pflag=0). At this time, pin 3 of the AND gate U3 also outputs a 0-level signal. Upon receiving the 0-level signal from the AND gate U3, the DSP circuit determines that no plasma has been generated in the chamber load and controls the ignition circuit to operate, gradually increasing the output level. As the real-time output current I increases, when it exceeds the set current threshold It, pin 3 of the first comparator U1 outputs a 1-level signal (Iflag outputs a high level). However, since the real-time output power P is still less than the set power threshold Pt, pin 3 of the second comparator U2 still outputs a 0-level signal (Pflag outputs a low level), and pin 3 of the AND gate U3 remains low. The sputtering power supply determines that no plasma has been generated in the chamber load, and the ignition circuit continues to operate. As the real-time output power P gradually increases to exceed the set power threshold Pt, pin 3 of the second comparator U2 outputs a 1-level signal (Pflag outputs a high level), and pin 3 of the AND gate U3 also outputs a high level. When the DSP circuit receives this high-level signal from the AND gate U3, it determines that plasma has been generated in the chamber load. The DSP controls the ignition circuit to shut down and controls it to output according to the set parameters, starting the sputtering coating stage. If the plasma extinguishes during the sputtering deposition stage, pin 3 of AND gate U3 will output a low level. The DSP circuit, receiving this low-level signal, determines that plasma generation has failed and restarts the ignition circuit to quickly restore the sputtered deposition to its state before the plasma extinguished. If multiple ignition failures exceed the failure threshold Nt, the ignition circuit shuts down, the system reports an error, and the operation / display panel prompts for process parameter modification. After modifying the relevant parameters on the operation / display panel, the sputtering deposition power supply can be restarted for another ignition attempt. Optimal process parameters can be obtained after multiple iterations.

[0057] A preferred embodiment of the present invention provides a method for generating plasma, such as... Figure 5-6 As shown, the method includes the following steps:

[0058] Step S1: Start the ignition circuit and set the circuit parameter thresholds;

[0059] Step S2: Obtain the real-time output voltage and real-time output current of the ignition circuit, and calculate the real-time output power;

[0060] Step S3: Compare the acquired real-time output current and the calculated real-time output power with the set parameter thresholds. If both are greater than the set values, proceed to step S4; otherwise, proceed to step S5.

[0061] Step S4: If both the real-time output current and the real-time output power are greater than the set values, it is determined that the plasma generation is successful, and the ignition circuit is turned off to carry out the second-stage sputtering coating process, and the number of ignition failures is set to 0.

[0062] Step S5: If at least one of the real-time output current and real-time output power is less than the set value, it is determined that the plasma generation has failed, the number of ignition failures is incremented by 1, and the ignition circuit is restarted.

[0063] Step S6: If the cumulative number of ignition failures does not exceed the threshold, the ignition circuit continues to work until the plasma generation is determined to be successful and the second-stage sputtering coating process is carried out. After success, the number of ignition failures is reset to 0.

[0064] Step S7: If the cumulative number of ignition failures exceeds the threshold, the ignition circuit will be shut down and the system will be prompted with an alarm error.

[0065] Furthermore, such as Figure 5-6As shown, after the sputtering coating operation begins, the power supply has no output; the real-time output voltage and real-time output current sampling values ​​are both 0, and the calculated real-time output power is also 0. At this time, the sputtering coating power supply system sets the number of consecutive ignition failures N to 0, the current threshold determination output Iflag to 0, and the power output determination Pflag to 0. Therefore, the sputtering coating power supply determines that no plasma is generated at this time. After the ignition circuit starts working, the ignition circuit causes the output voltage of the sputtering coating power supply to rise to a set value. The specific voltage rise value depends on the specific process setting; in this invention, it rises to 1000V. The sampled real-time output voltage V and real-time output current I are multiplied to obtain the real-time output power P. During the ignition process, when the real-time output current I exceeds the set current threshold It, the current threshold determination output Iflag=1; otherwise, the current threshold determination output Iflag=0. Similarly, when the real-time output power exceeds the set power threshold Pt, the power threshold determination output Pflag=1; otherwise, the power threshold determination output Pflag=0. The plasma generation status is determined based on the signal combination of Iflag and Pflag. When both Iflag and Pflag are 1, plasma generation is considered successful. The sputtering power supply's ignition circuit operates, the ignition circuit shuts down, and the second stage of the sputtering deposition process begins. The number of consecutive ignition failures N is set to 0. When neither Iflag nor Pflag is 1, the sputtering power supply determines plasma generation has failed and increments the number of consecutive ignition failures N by 1. If the number of consecutive ignition failures N does not exceed the set threshold Nt, the ignition circuit continues operating, maintaining the ignition phase until plasma generation is considered successful. If the number of consecutive ignition failures N exceeds the threshold Nt, the sputtering power supply determines that the current ignition conditions cannot be met, shuts down the ignition circuit, and the system reports an error and prompts for parameter modification.

[0066] Furthermore, after successful ignition, during the second-stage sputtering coating process, if a hard arc or other event causes the sputtering coating power supply to temporarily shut down, resulting in Iflag and Pflag not being simultaneously 1, the sputtering coating power supply determines that the plasma is extinguished, and the ignition circuit restarts, automatically re-entering the ignition stage. If the number of consecutive ignition failures N exceeds the set failure threshold Nt, causing a system error, it indicates that the process parameters are incorrect and ignition cannot be achieved. The sputtering coating process parameters need to be adjusted; for example, the ignition voltage can be increased to 1200V, or the atmosphere pressure within the sputtering chamber can be changed, and ignition can be attempted again.

[0067] It should be understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A control circuit for plasma generation, comprising an input rectifier and filter circuit, an ignition circuit, an output filter circuit, a DSP circuit, and an input circuit; The input rectifier and filter circuit is used to connect to the input AC power, rectify the input AC power into DC power, and then filter the DC power. The ignition circuit is connected to the input rectifier and filter circuit, and raises the filtered voltage to the set value. The output filter circuit, connected to the ignition circuit, filters the voltage that has risen to a set value before outputting it to the chamber load. Its features include: The DSP circuit is connected to the output filter circuit and the ignition circuit, and obtains the real-time current value and real-time voltage value output by the output filter circuit, and calculates the real-time power value from the obtained real-time current value and real-time voltage value. The input circuit, electrically connected to the DSP circuit, is used to input the set current threshold, power threshold, and ignition failure count threshold. The DSP circuit compares the real-time current value with the set current threshold and the real-time power value with the set power threshold. Only when the real-time current value is greater than the set current threshold and the real-time power value is greater than the set power threshold is the plasma generation determined to be successful, and the ignition circuit is controlled to be turned off, while the number of ignition failures is reset. Otherwise, plasma generation is deemed a failure, the ignition circuit is kept on, and the number of ignition failures is incremented by 1. When the cumulative number of ignition failures exceeds the set threshold, the ignition circuit is shut down and a system alarm is triggered.

2. The control circuit according to claim 1, characterized in that: The ignition circuit includes a functional circuit and a power circuit. The functional circuit generates an ignition high voltage, and the power circuit provides input power to the chamber load. The DSP circuit compares the real-time current value and real-time power value with the set current threshold and power threshold to control the start and stop of the functional circuit.

3. The control circuit according to claim 1, characterized in that: The input rectifier and filter circuit includes a rectifier circuit and a filter circuit. The rectifier circuit consists of multiple sets of diodes, which are connected to the three-phase input AC power and rectify it into DC power. The ignition circuit consists of a driver circuit and a MOSFET. The output filter circuit consists of multiple sets of diodes and is connected to a voltage detection circuit and a current detection circuit. The voltage detection circuit and the current detection circuit acquire real-time voltage and current values. The control circuit is also equipped with a multiplier to calculate the real-time power. The current detection circuit and voltage detection circuit are connected to the DSP circuit through a comparator and an AND gate. The comparator compares the real-time current value with the set current threshold and the real-time power value with the set power threshold. The AND gate sends the comparison result to the DSP circuit, which then controls the ignition circuit to turn on or off.

4. A method for controlling plasma generation, comprising connecting an input AC power supply and setting a current threshold and a power threshold, rectifying the input AC power supply into DC power and then filtering it, increasing the filtered voltage to a set value, and then outputting the increased voltage after output filtering to the chamber load, characterized in that: The system acquires the real-time output voltage and current values ​​to the chamber load and calculates the real-time output power value. It then compares the real-time output power value and the real-time output current value with the set power threshold and the set current threshold. Only when the real-time output current value is greater than the set current threshold and the real-time output power value is greater than the set power threshold is the plasma generation determined to be successful. The system then disables the voltage increase function and resets the number of ignition failures. Otherwise, plasma generation is deemed a failure, the function to control voltage increase remains on, and the count of failed ignition attempts is incremented by 1. When the cumulative number of ignition failures exceeds the set threshold, the ignition circuit is shut down and a system alarm is triggered.

5. A method for generating plasma, characterized in that, The method of generation includes the following steps: S1: Start the ignition circuit and set the current threshold, power threshold, and ignition failure count threshold; S2: Obtain the real-time output voltage and real-time output current of the ignition circuit, and calculate the real-time output power; S3: Compare the acquired real-time output current and calculated real-time output power with the set current threshold and set power threshold. S4: Determine the plasma generation status based on the comparison results. Only when the real-time output current is greater than the set current threshold and the real-time output power is greater than the set power threshold, the plasma generation is determined to be successful. The ignition circuit is then turned off to perform the second-stage sputtering coating process, and the number of ignition failures is set to 0. Otherwise, plasma generation is deemed a failure, the count of failed ignition is incremented by 1, and the ignition circuit is restarted. S5: If the number of ignition failures does not exceed the set threshold for the number of ignition failures, repeat steps S2-S4 until plasma is successfully generated. If the number of ignition failures exceeds the set threshold, the ignition circuit will be shut down and a system alarm will be triggered.

6. The generation method according to claim 5, characterized in that: In the two-stage sputtering coating process, the output current and output voltage are detected in real time and the real-time output power is calculated. If the real-time output current is less than the set current threshold or the real-time output power is less than the set power threshold, the plasma is determined to be extinguished, the ignition circuit is restarted, and the number of ignition failures is accumulated. If the number of ignition failures is greater than the set ignition failure number threshold, the system reports an error and shuts down the system.

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