A plasma radio frequency power supply arc detection and suppression method

Abstract

The present invention discloses a plasma RF power supply arc detection and suppression method. First, the output voltage and output current of the RF power supply are obtained through a sampling circuit module. Then, micro-arcs and hard arcs are distinguished through specific discrimination criteria, and corresponding control strategies are adopted to suppress arcs. Ultimately, rapid detection and effective suppression of arcs are achieved, improving the quality of thin film deposition and avoiding irreversible damage to the workpiece surface. Finally, the optimal micro-arc parameters of the plasma RF power supply can be designed. By adjusting the micro-arc interruption time, voltage threshold, and current threshold, and recording the frequency of hard arcs and soft arcs, the optimal micro-arc interruption time and related parameters are calculated to achieve optimal treatment of micro-arcs. By using the plasma RF power supply arc detection and suppression technology proposed by the present invention, the generation of arcs can be detected and suppressed in a timely manner, protecting the workpiece surface, improving the quality of thin film deposition, and reducing the defective rate of workpieces.

Description

Technical Field

[0001] The present invention relates to the field of plasma thin film deposition technology, and in particular to a radio frequency power supply arc detection and suppression method used in plasma thin film deposition technology. Background Art

[0002] Plasma processing equipment is widely used in the field of semiconductor processing, such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). For example, the common plasma-enhanced chemical vapor deposition (PECVD) method uses plasma generated by glow discharge to decompose gases and rapidly react to form thin films.

[0003] Radio frequency power supplies are widely used in plasma thin film deposition processes such as PECVD and PVD. In the thin film deposition process, radio frequency power supplies are used to excite and generate plasma. Arc ignition is easily generated due to factors such as local charge accumulation on the workpiece surface, surface tip discharge, and changes in the cavity atmosphere. If effective measures are not taken in a timely manner, the quality of thin film deposition will be affected, and even irreversible damage will be caused to the workpiece surface, resulting in the scrapping of the workpiece. Therefore, in the plasma thin film deposition process, rapid arc detection and effective arc suppression are crucial. In order to reduce the adverse effects of arc discharge, it is hoped that the arc can be automatically detected in the early stages of the arc formation process so that the power output can be shut down as soon as possible to reduce the hazards of the arc that has occurred. By proposing a new plasma radio frequency power supply arc detection and suppression technology, the stability and yield of the thin film deposition process can be effectively improved. Summary of the Invention

[0004] To address these issues, the present invention proposes a method for detecting and suppressing arcs in a plasma RF power supply, comprising an RF power supply output voltage sensing and sampling circuit module, an RF power supply output current sensing and sampling circuit module, and an arc detection and suppression module. The RF power supply output voltage and output current are acquired via voltage and current sensors. The output voltage and output current are compared with preset voltage and current thresholds to identify micro-arcs and hard arcs. Based on the detection results, the RF power supply output is controlled to interrupt and extinguish the arc to prevent damage to the workpiece. After the hard arc interruption period, the RF power supply output is gradually restored to ensure continuous and stable operation.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for detecting and suppressing arc in a plasma radio frequency power supply is characterized by comprising the following steps:

[0007] S1: Perform arc detection on the plasma RF power supply through the arc detection module:

[0008] S11: Using the output voltage sampling module, obtain the output voltage Uo of the RF power supply;

[0009] S12: using the output current sampling module to obtain the output current Io of the RF power supply;

[0010] S13: Compare the output voltage Uo with a preset voltage threshold Uth, and compare the output current Io with a preset current threshold Ith. When Uo is less than Uth and Io is greater than Ith, it is determined to be a UXI arc, also known as a micro arc. Compare the output current Io with a preset current threshold Ith1. When Io is greater than Ith1, it is determined to be an Imax arc, also known as a hard arc.

[0011] S2: Suppress the arc of the plasma RF power supply through the arc suppression module:

[0012] S21: When it is determined that a micro-arc occurs, the output of the RF power supply is controlled to be turned off according to a predetermined micro-arc interruption time Tmicro, so that the micro-arc is extinguished;

[0013] S22: When a hard arc is detected, the output of the RF power supply is controlled to be turned off according to a predetermined hard arc interruption time TImax, so that the hard arc is extinguished; after the TImax time, the output of the RF power supply is controlled to restart the ramp according to a predetermined slope to restore the output;

[0014] S3: Design the optimal micro-arc parameters of the plasma RF power supply:

[0015] S31: setting the voltage threshold Uth related to the micro-arc to the minimum value and the current threshold Ith to the maximum value;

[0016] S32: Enable the hard arc action function and disable the soft arc action function;

[0017] S33: Record the frequency of hard arc and soft arc of the RF power supply at this time, that is, the number of hard arc and soft arc occurrences per unit time, recorded as RImax0 and RUXI0 respectively;

[0018] S34: Enable the hard arc and soft arc action functions at the same time, and set the micro arc interruption time Tmicro to the minimum value;

[0019] S35: Record the frequency of hard arc and soft arc of the RF power supply at this time, that is, the number of hard arc and soft arc occurrences per unit time, recorded as RImax1 and RUXI1 respectively;

[0020] S36: gradually increase the micro-arc interruption time, and record the frequency of hard arc and soft arc occurrence of the RF power supply at each TmicroI (I=1, 2, 3, ...), that is, the number of hard arc and soft arc occurrence per unit time, respectively recorded as RImaxI and RUXII (I=1, 2, 3, ...);

[0021] S37: gradually increase the voltage threshold Uth, decrease the current threshold Ith, and repeat steps S2 to S6;

[0022] S38: Calculate the hard arc and soft arc occurrence ratios in each case using the following formulas: R1Imax= RImax0 / RImaxI, R1UXI= RUXI0 / RUXII;

[0023] S39: Calculate the micro-arc interruption time of the RF power supply in each case, using the following formula: TI = TmicroI * R1UXI;

[0024] S310: Evaluate the optimal setting of the micro-arc, and obtain the optimal micro-arc parameters according to the optimal position. The optimal micro-arc parameters are such that the hard arc occurrence ratio is maximized and the micro-arc interruption time is minimized.

[0025] In the above structure: A plasma RF power supply arc detection and suppression method proposed by the present invention includes the following steps: first, arc detection is performed on the plasma RF power supply through an arc detection module, then the arc of the plasma RF power supply is suppressed through an arc suppression module, and finally, the optimal micro-arc parameters of the plasma RF power supply are designed.

[0026] Among them, when the arc detection module is used to detect the arc of the plasma RF power supply, the output current and output voltage of the RF power supply are respectively obtained by setting up the output voltage sampling module and the output current sampling module. The output voltage and output current are compared with the preset voltage threshold and current threshold through the set arc detection module to identify micro arcs and hard arcs, thereby completing the arc detection of the RF power supply output.

[0027] The arc detection module detects arcs using a voltage sensor and a current sensor, respectively, to measure the RF power supply's output voltage and current. These signals are then compared with preset voltage and current thresholds to identify micro-arcs and hard arcs. Arc detection with the module ensures timely detection and identification of arcing issues, providing an accurate basis for subsequent arc suppression.

[0028] When an arc occurs, the arc suppression module must be used to suppress the plasma RF power supply arc. The RF power supply output voltage changes faster than the current. By detecting the RF power supply output voltage amplitude, the presence of arcing can be quickly determined, and the RF power supply output pulse voltage can be quickly shut down. At this point, the arc current is only slightly higher than the steady-state output current, indicating a micro arc. If the output voltage is lower than the set voltage threshold uth and the output current is greater than the set current threshold ith, the arc is considered a micro arc. If the output current increases too quickly during arcing, exceeding the preset current threshold ith1, the arc is considered a hard arc.

[0029] When performing arc suppression, the arc suppression module controls the RF power supply output to interrupt and extinguish the arc based on the detected arc type. For example, if a micro-arc is detected, the RF power supply output is controlled to shut down for a predetermined micro-arc interruption time to prevent the micro-arc from developing into a hard arc. If a hard arc is detected, the RF power supply output is controlled to shut down for a predetermined hard arc interruption time to extinguish the hard arc.

[0030] Finally, the optimal micro-arc parameters for the plasma RF power supply were designed. By recording the frequency of hard and soft arcs and gradually adjusting the micro-arc interruption time, voltage threshold, and current threshold, the optimal micro-arc parameters were calculated. This minimized the hard arc rate and minimized the micro-arc interruption time, achieving optimal micro-arc suppression. This ultimately led to the design of the optimal micro-arc parameters for the plasma RF power supply.

[0031] As a preferred technical solution of the present invention: it also includes a full-bridge inverter, the output voltage sampling module and the output current sampling module are respectively connected to the arc detection module, the arc detection module is connected to the arc suppression module, the arc suppression module is connected to the full-bridge inverter, and the full-bridge inverter is connected to the load. When it is determined that a hard arc occurs, the output of the RF power supply is controlled to be shut down according to the predetermined hard arc interruption time TImax. After the TImax time, the RF power supply output is output to the load through the full-bridge inverter to achieve output current continuity.

[0032] In the above structure, the full-bridge inverter is provided to achieve output current continuity. When a hard arc is detected, the output of the RF power supply is controlled to be shut down according to the predetermined hard arc interruption time TImax. After the TImax time, the RF power supply output is output to the load through the full-bridge inverter, thereby achieving output current continuity.

[0033] As a preferred technical solution of the present invention: the output voltage sampling module includes a voltage sensor and a voltage sampling circuit, and the voltage sensor is respectively connected to the voltage sampling circuit and the output end of the RF power supply; the output current sampling module includes a current sensor and a current sampling circuit, and the current sensor is respectively connected to the current sampling circuit and the output end of the RF power supply.

[0034] As a preferred technical solution of the present invention: the voltage sampling circuit and the current sampling circuit are respectively connected to the arc detection module, and are used to input the output voltage Uo and output current Io of the RF power supply.

[0035] In the above structure: the output voltage sampling module includes a voltage sensor and a voltage sampling circuit, the voltage sensor is respectively connected to the voltage sampling circuit and the output end of the RF power supply, and the output voltage of the RF power supply is collected through the voltage sensor; the output current sampling module includes a current sensor and a current sampling circuit, the current sensor is respectively connected to the current sampling circuit and the output end of the RF power supply, and the output current of the RF power supply is collected through the current sensor, the voltage sampling circuit and the current sampling circuit are respectively connected to the arc detection module, and the input voltage sensor and current sensor obtain the output voltage Uo and output current Io of the RF power supply and input them into the arc detection module.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The sampling module of the RF power supply output voltage and current can monitor the generation and change of arc in real time, ensuring the rapid detection of arc.

[0038] (2) Micro arcs and hard arcs are distinguished by discrimination criteria, and corresponding control strategies are adopted to suppress arcs, which can prevent micro arcs from further developing into hard arcs and avoid damage to the workpiece surface caused by hard arcs.

[0039] (3) By gradually adjusting the micro-arc interruption time and the voltage threshold and current threshold, the optimal micro-arc parameters are calculated. Finally, the optimal micro-arc parameters of the plasma RF power supply can be designed. The optimal setting of the micro-arc can be evaluated according to the actual process conditions, thereby improving the surface quality of the workpiece and the thin film deposition effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is the principle framework diagram of the present invention;

[0041] Figure 2 This is a flow chart of the rapid hierarchical detection of the plasma radio frequency power arc in the present invention;

[0042] Figure 3 This is a flow chart of arc suppression of the plasma radio frequency power supply in the present invention;

[0043] Figure 4 Schematic diagram of micro-arc determination in the present invention;

[0044] Figure 5 Schematic diagram of hard arc determination in the present invention. Implementation Method

[0045] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0046] The present invention proposes a method for detecting and suppressing arc in a plasma radio frequency power supply, comprising the following steps:

[0047] S1: Perform arc detection on the plasma RF power supply through the arc detection module:

[0048] S11: Using the output voltage sampling module, obtain the output voltage Uo of the RF power supply;

[0049] S12: using the output current sampling module to obtain the output current Io of the RF power supply;

[0050] S13: Compare the output voltage Uo with a preset voltage threshold Uth, and compare the output current Io with a preset current threshold Ith. When Uo is less than Uth and Io is greater than Ith, it is determined to be a UXI arc, also known as a micro arc. Compare the output current Io with a preset current threshold Ith1. When Io is greater than Ith1, it is determined to be an Imax arc, also known as a hard arc.

[0051] S2: Suppress the arc of the plasma RF power supply through the arc suppression module:

[0052] S21: When it is determined that a micro-arc occurs, the output of the RF power supply is controlled to be turned off according to a predetermined micro-arc interruption time Tmicro, so that the micro-arc is extinguished;

[0053] S22: When a hard arc is detected, the output of the RF power supply is controlled to be turned off according to a predetermined hard arc interruption time TImax, so that the hard arc is extinguished; after the TImax time, the output of the RF power supply is controlled to restart the ramp according to a predetermined slope to restore the output;

[0054] S3: Design the optimal micro-arc parameters of the plasma RF power supply:

[0055] S31: setting the voltage threshold Uth related to the micro-arc to the minimum value and the current threshold Ith to the maximum value;

[0056] S32: Enable the hard arc action function and disable the soft arc action function;

[0057] S33: Record the frequency of hard arc and soft arc of the RF power supply at this time, that is, the number of hard arc and soft arc occurrences per unit time, recorded as RImax0 and RUXI0 respectively;

[0058] S34: Enable the hard arc and soft arc action functions at the same time, and set the micro arc interruption time Tmicro to the minimum value;

[0059] S35: Record the frequency of hard arc and soft arc of the RF power supply at this time, that is, the number of hard arc and soft arc occurrences per unit time, recorded as RImax1 and RUXI1 respectively;

[0060] S36: gradually increase the micro-arc interruption time, and record the frequency of hard arc and soft arc occurrence of the RF power supply at each TmicroI (I=1, 2, 3, ...), that is, the number of hard arc and soft arc occurrence per unit time, respectively recorded as RImaxI and RUXII (I=1, 2, 3, ...);

[0061] S37: gradually increase the voltage threshold Uth, decrease the current threshold Ith, and repeat steps S2 to S6;

[0062] S38: Calculate the hard arc and soft arc occurrence ratios in each case using the following formulas: R1Imax= RImax0 / RImaxI, R1UXI= RUXI0 / RUXII;

[0063] S39: Calculate the micro-arc interruption time of the RF power supply in each case, using the following formula: TI = TmicroI * R1UXI;

[0064] S310: Evaluate the optimal setting of the micro-arc, and obtain the optimal micro-arc parameters according to the optimal position. The optimal micro-arc parameters are such that the hard arc occurrence ratio is maximized and the micro-arc interruption time is minimized.

[0065] The present invention proposes a plasma RF power supply arc detection and suppression method, which includes the following steps: first, arc detection is performed on the plasma RF power supply through an arc detection module, then arc suppression is performed on the plasma RF power supply through an arc suppression module, and finally, the optimal micro-arc parameters of the plasma RF power supply are designed.

[0066] like Figure 2 As shown, when the arc detection module is used to detect the arc of the plasma RF power supply, the output current and output voltage of the RF power supply are respectively obtained by setting up an output voltage sampling module and an output current sampling module. The output voltage and output current are compared with the preset voltage threshold and current threshold by the set arc detection module to identify micro arcs and hard arcs, thereby completing the arc detection of the RF power supply output.

[0067] The arc detection module detects arcs using a voltage sensor and a current sensor, respectively, to measure the RF power supply's output voltage and current. These signals are then compared with preset voltage and current thresholds to identify micro-arcs and hard arcs. Arc detection with the module ensures timely detection and identification of arcing issues, providing an accurate basis for subsequent arc suppression.

[0068] When an arc occurs, the arc of the plasma RF power supply needs to be suppressed by the arc suppression module. The change of the RF power supply output voltage is faster than the current change. The output voltage amplitude of the RF power supply can be detected to quickly determine whether the arc phenomenon occurs and quickly shut down the RF power supply output pulse voltage. At this time, the arc current is only slightly higher than the steady-state output current. The arc type is micro-arc. The judgment of micro-arc is combined with Figure 4 To illustrate, if the output voltage is lower than the set voltage threshold uth and the output current is greater than the set current threshold ith, the arc is judged as a micro arc. Figure 5 To illustrate, if the output current increases too quickly when an arc is generated and is greater than a preset current threshold ith1, the arc is determined to be a hard arc.

[0069] Figure 4 In the figure, uth is the preset voltage threshold, ith is the preset current threshold, and Tmicro is the preset micro-arc shutdown time.

[0070] Figure 5 In the figure, ith1 is the preset hard arc current threshold, and TImax is the preset hard arc shutdown time.

[0071] like Figure 3 As shown, the arc suppression module controls the RF power supply output to interrupt and extinguish the arc based on the detected arc type. For example, if a micro-arc is detected, the RF power supply output is shut off for a predetermined micro-arc interruption time to prevent the micro-arc from developing into a hard arc. If a hard arc is detected, the RF power supply output is shut off for a predetermined hard arc interruption time to extinguish the hard arc.

[0072] Finally, the optimal micro-arc parameters for the plasma RF power supply were designed. By recording the frequency of hard and soft arcs and gradually adjusting the micro-arc interruption time, voltage threshold, and current threshold, the optimal micro-arc parameters were calculated. This minimized the hard arc rate and minimized the micro-arc interruption time, achieving optimal micro-arc suppression. This ultimately led to the design of the optimal micro-arc parameters for the plasma RF power supply.

[0073] like Figure 1As shown, in this embodiment: a full-bridge inverter is also included, the output voltage sampling module and the output current sampling module are respectively connected to the arc detection module, the arc detection module is connected to the arc suppression module, the arc suppression module is connected to the full-bridge inverter, and the full-bridge inverter is connected to the load. When it is determined that a hard arc occurs, the output of the RF power supply is controlled to be turned off according to the predetermined hard arc interruption time TImax. After the TImax time, the RF power supply output is output to the load through the full-bridge inverter to achieve continuity of the output current.

[0074] The full-bridge inverter is set up to achieve output current continuity. When a hard arc is detected, the output of the RF power supply is controlled to be shut down according to the predetermined hard arc interruption time TImax. After the TImax time, the RF power supply output is output to the load through the full-bridge inverter, thereby achieving output current continuity.

[0075] In this embodiment, the output voltage sampling module includes a voltage sensor and a voltage sampling circuit, the voltage sensor being connected to the voltage sampling circuit and the output terminal of the RF power supply, respectively. The output current sampling module includes a current sensor and a current sampling circuit, the current sensor being connected to the current sampling circuit and the output terminal of the RF power supply, respectively. The voltage sampling circuit and the current sampling circuit are each connected to the arc detection module and are used to input the acquired output voltage Uo and output current Io of the RF power supply.

[0076] The output voltage sampling module includes a voltage sensor and a voltage sampling circuit. The voltage sensor is respectively connected to the voltage sampling circuit and the output end of the RF power supply. The output voltage of the RF power supply is collected through the voltage sensor. The output current sampling module includes a current sensor and a current sampling circuit. The current sensor is respectively connected to the current sampling circuit and the output end of the RF power supply. The output current of the RF power supply is collected through the current sensor. The voltage sampling circuit and the current sampling circuit are respectively connected to the arc detection module. The input voltage sensor and the current sensor obtain the output voltage Uo and output current Io of the RF power supply and input them into the arc detection module.

[0077] In summary:

[0078] The present invention adopts a sampling module for the output voltage and current of the radio frequency power supply, which can monitor the generation and change of the arc in real time and ensure the rapid detection of the arc.

[0079] The present invention distinguishes micro-arcs from hard arcs through a discrimination criterion and adopts a corresponding control strategy to perform arc suppression processing, which can prevent the micro-arc from further developing into a hard arc and avoid damage to the workpiece surface caused by the hard arc.

[0080] The present invention calculates the optimal micro-arc parameters by gradually adjusting the micro-arc interruption time and the voltage threshold and current threshold, and ultimately designs the optimal micro-arc parameters of the plasma RF power supply. It can evaluate the optimal setting of the micro-arc according to the actual process conditions, and improve the surface quality of the workpiece and the thin film deposition effect.

[0081] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent variation based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A method for detecting and suppressing arc in a plasma radio frequency power supply, characterized in that: The steps include: S1: Perform arc detection on the plasma RF power supply through the arc detection module: S11: Using the output voltage sampling module, obtain the output voltage Uo of the RF power supply; S12: using the output current sampling module to obtain the output current Io of the RF power supply; S13: Compare the output voltage Uo with a preset voltage threshold Uth, and compare the output current Io with a preset current threshold Ith. When Uo is less than Uth and Io is greater than Ith, it is determined to be a UXI arc, also known as a micro arc. Compare the output current Io with a preset current threshold Ith1. When Io is greater than Ith1, it is determined to be an Imax arc, also known as a hard arc. S2: Suppress the arc of the plasma RF power supply through the arc suppression module: S21: When it is determined that a micro-arc occurs, the output of the RF power supply is controlled to be turned off according to a predetermined micro-arc interruption time Tmicro, so that the micro-arc is extinguished; S22: When a hard arc is detected, the output of the RF power supply is controlled to be turned off according to a predetermined hard arc interruption time TImax, so that the hard arc is extinguished; after the TImax time, the output of the RF power supply is controlled to restart the ramp according to a predetermined slope to restore the output; S3: Design the optimal micro-arc parameters of the plasma RF power supply: S31: setting the voltage threshold Uth related to the micro-arc to the minimum value and the current threshold Ith to the maximum value; S32: Enable the hard arc action function and disable the soft arc action function; S33: Record the frequency of hard arc and soft arc of the RF power supply at this time, that is, the number of hard arc and soft arc occurrences per unit time, recorded as RImax0 and RUXI0 respectively; S34: Enable the hard arc and soft arc action functions at the same time, and set the micro arc interruption time Tmicro to the minimum value; S35: Record the frequency of hard arc and soft arc of the RF power supply at this time, that is, the number of hard arc and soft arc occurrences per unit time, recorded as RImax1 and RUXI1 respectively; S36: gradually increase the micro-arc interruption time, and record the frequency of hard arc and soft arc occurrence of the RF power supply at each TmicroI (I=1, 2, 3, ...), that is, the number of hard arc and soft arc occurrence per unit time, respectively recorded as RImaxI and RUXII (I=1, 2, 3, ...); S37: gradually increase the voltage threshold Uth, decrease the current threshold Ith, and repeat steps S2 to S6; S38: Calculate the hard arc and soft arc occurrence ratios in each case using the following formulas: R1Imax= RImax0 / RImaxI, R1UXI= RUXI0 / RUXII; S39: Calculate the micro-arc interruption time of the RF power supply in each case, using the following formula: TI = TmicroI * R1UXI; S310: Evaluate the optimal setting of the micro-arc, and obtain the optimal micro-arc parameters according to the optimal position. The optimal micro-arc parameters are such that the hard arc occurrence ratio is maximized and the micro-arc interruption time is minimized.

2. The method for detecting and suppressing arc in a plasma radio frequency power supply according to claim 1, wherein: It also includes a full-bridge inverter, the output voltage sampling module and the output current sampling module are respectively connected to the arc detection module, the arc detection module is connected to the arc suppression module, the arc suppression module is connected to the full-bridge inverter, and the full-bridge inverter is connected to the load. When it is determined that a hard arc occurs, the output of the RF power supply is controlled to be shut down according to the predetermined hard arc interruption time TImax. After the TImax time, the RF power supply output is output to the load through the full-bridge inverter to achieve continuity of the output current.

3. The method for detecting and suppressing arc in a plasma radio frequency power supply according to claim 2, wherein: The output voltage sampling module includes a voltage sensor and a voltage sampling circuit, and the voltage sensor is connected to the voltage sampling circuit and the output end of the RF power supply respectively. The output current sampling module includes a current sensor and a current sampling circuit, and the current sensor is connected to the current sampling circuit and the output end of the RF power supply respectively.

4. The method for detecting and suppressing arc in a plasma radio frequency power supply according to claim 3, wherein: The voltage sampling circuit and the current sampling circuit are respectively connected to the arc detection module, and are used to input the output voltage Uo and the output current Io of the radio frequency power supply.

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