Method of determining plasma ignition, control method of semiconductor process equipment

Abstract

The embodiment of the present application provides a method for determining plasma ignition, a control method of a semiconductor process equipment, and the semiconductor process equipment, and the semiconductor process equipment comprises a radio frequency coil, and the method comprises the following steps: monitoring a change rate of an electric parameter of the radio frequency coil after radio frequency power is applied to the radio frequency coil, the change rate of the electric parameter comprising a change rate of a current flowing through the radio frequency coil or a change rate of a voltage across the radio frequency coil; and determining plasma ignition when a ratio of the change rate of the electric parameter detected at a current moment to the change rate of the electric parameter detected at a previous moment exceeds a preset ratio threshold value or a difference value exceeds a preset difference threshold value, so that the ignition moment of the semiconductor process equipment can be accurately judged according to plasma ignition, the next radio frequency system is prevented from being started before the semiconductor process equipment is ignited, and the safety of the semiconductor process equipment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency system control, and in particular to a method for determining plasma ignition and a control method for semiconductor process equipment. Background Art

[0002] Semiconductor processing equipment, such as etching systems, consists of an upper RF system for generating plasma and a lower RF system for regulating and controlling ion energy. Typically, the upper RF system must be activated first, and only after ignition and plasma generation within the chamber can the lower RF system be activated. Otherwise, the lower RF system will generate very high bias voltages, causing component ignition and potentially damaging the lower RF system. Therefore, accurately determining the ignition timing of the upper RF system can prevent the lower RF system from being activated before ignition within the chamber, thereby improving the safety of semiconductor processing equipment. Summary of the Invention

[0003] In order to solve the above problems, embodiments of the present invention disclose a method for determining plasma ignition and a method for controlling semiconductor process equipment.

[0004] In a first aspect, an embodiment of the present invention provides a method for determining plasma ignition, which is used in semiconductor process equipment, wherein the semiconductor process equipment includes a radio frequency coil, and the method includes:

[0005] After applying radio frequency power to the radio frequency coil, monitoring a rate of change of an electrical parameter of the radio frequency coil or a rate of change of a voltage across the radio frequency coil;

[0006] When the ratio of the electrical parameter change rate detected at the current moment to the electrical parameter change rate detected at the previous moment exceeds a preset ratio threshold or the difference exceeds a preset difference threshold, it is determined that the plasma has ignited.

[0007] Optionally, monitoring the rate of change of an electrical parameter of the radio frequency coil includes:

[0008] collecting a current value flowing through the radio frequency coil;

[0009] A rate of change of the current flowing through the radio frequency coil is determined according to the current value and a sampling time corresponding to the current value.

[0010] Optionally, monitoring the rate of change of an electrical parameter of the radio frequency coil includes:

[0011] collecting voltage values ​​across the radio frequency coil;

[0012] A voltage change rate across the radio frequency coil is determined according to the voltage value and a sampling time corresponding to the voltage value.

[0013] Optionally, the radio frequency coil includes an inner radio frequency coil and an outer radio frequency coil, and monitoring the rate of change of an electrical parameter of the radio frequency coil includes:

[0014] determining a rate of change of current flowing through the inner radio frequency coil;

[0015] and / or,

[0016] A rate of change of current through the external radio frequency coil is determined.

[0017] Optionally, the radio frequency coil includes an inner radio frequency coil and an outer radio frequency coil, and monitoring the rate of change of an electrical parameter of the radio frequency coil includes:

[0018] determining a rate of change of voltage across the inner radio frequency coil;

[0019] and / or,

[0020] The rate of change of voltage across the external radio frequency coil is determined.

[0021] Optionally, the semiconductor process equipment includes a matcher disposed between a radio frequency power source and the radio frequency coil, the matcher includes a current sensor connected in series with the radio frequency coil, and collecting the current value flowing through the radio frequency coil includes:

[0022] A current value of the current flowing through the radio frequency coil collected by the current sensor is obtained.

[0023] Optionally, the semiconductor process equipment includes a matcher disposed between a radio frequency power supply and the radio frequency coil, the matcher includes a voltage sensor connected in series with the radio frequency coil, and collecting the voltage value across the radio frequency coil includes:

[0024] The voltage value across the radio frequency coil collected by the voltage sensor is obtained.

[0025] Optionally, the preset ratio threshold is any value between 3 and 100.

[0026] In a second aspect, an embodiment of the present invention provides a method for controlling semiconductor process equipment, wherein the semiconductor process equipment includes a radio frequency coil and a wafer carrier, and the method includes:

[0027] applying a first radio frequency power to the radio frequency coil;

[0028] Using the method for determining plasma ignition as described above, determining whether the plasma has ignited;

[0029] After the plasma is ignited, a second radio frequency power is applied to the bias electrode of the wafer supporting device.

[0030] In a third aspect, an embodiment of the present invention provides a semiconductor process apparatus, comprising: a process chamber, a radio frequency coil, a wafer carrier, a first radio frequency power supply electrically connected to the radio frequency coil, and a second radio frequency power supply electrically connected to a bias electrode of the wafer carrier, wherein the wafer carrier is disposed in the process chamber; and

[0031] A controller comprising at least one memory and at least one processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, implements the steps of a method for determining plasma ignition as described in any one of the above items, or implements the steps of a method for controlling semiconductor process equipment as described above.

[0032] The embodiments of the present invention include the following advantages:

[0033] Embodiments of the present invention monitor the rate of change of the electrical parameters of the RF coil and determine plasma ignition when the ratio of the current rate of change to the previous rate of change exceeds a preset ratio threshold, or the difference exceeds a preset difference threshold. By determining plasma ignition based on a sudden change in the rate of change of the electrical parameters of the RF coil, embodiments of the present invention can accurately determine the ignition timing of semiconductor processing equipment based on plasma ignition, avoiding the need to activate the RF system before ignition of the semiconductor processing equipment, thereby improving the safety of semiconductor processing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a structural diagram of a semiconductor process equipment according to an embodiment of the present invention;

[0036] Figure 2 It is a logic diagram of a control method of a semiconductor process equipment in the related art;

[0037] Figure 3 It is a logic diagram of another control method of semiconductor process equipment in related technology;

[0038] Figure 4 It is a logic diagram of another control method of semiconductor process equipment in related technology;

[0039] Figure 5 is an equivalent circuit diagram of a semiconductor process equipment according to an embodiment of the present invention;

[0040] Figure 6 This is a plasma resistance change curve diagram of a semiconductor process equipment according to an embodiment of the present invention;

[0041] Figure 7 This is a curve diagram of a capacitance matching path change of a semiconductor process equipment according to an embodiment of the present invention;

[0042] Figure 8 is a graph showing changes in radio frequency coil current versus plasma resistance of a semiconductor process equipment according to an embodiment of the present invention;

[0043] Figure 9 is a flowchart of the steps of a method for determining plasma ignition according to an embodiment of the present invention;

[0044] Figure 10 This is an internal network diagram of a matcher of a semiconductor process equipment according to an embodiment of the present invention;

[0045] Figure 11 This is a flowchart of a method for controlling semiconductor process equipment according to an embodiment of the present invention;

[0046] Figure 12 is a logic diagram of another control method for semiconductor process equipment according to an embodiment of the present invention;

[0047] Figure 13 It is a structural block diagram of a semiconductor process equipment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Reference Figure 1, shows a structural diagram of a semiconductor process equipment according to an embodiment of the present invention. The semiconductor process equipment may be an etcher system, more specifically an ICP (inductively coupled plasma) etcher system. The semiconductor process equipment includes an upper matcher 101, an inner RF coil 102, an outer RF coil 103, an electrostatic chuck 104, an interface plate 105, a lower matcher 106, and a process chamber 107. Semiconductor process equipment typically has multiple different RF systems, one of which is used to generate plasma, and the ion flux can be controlled by adjusting the parameters of the RF system. Another RF system is used to generate a bias voltage on the wafer surface for adjusting and controlling ion energy. The upper RF system, consisting of the RF coil and the upper matcher, is used to generate plasma. The lower RF system, also known as a wafer carrier, consisting of the electrostatic chuck, the interface plate, and the lower matcher, is used to generate a bias voltage and control ion energy. The two RF systems must be activated sequentially. Generally, the upper RF system must be activated first. Once the plasma is generated in the process chamber, the lower RF system can be activated. Otherwise, very high bias voltages will be generated, potentially damaging the lower RF system. This damage occurs when components in the lower RF system ignite due to high voltage. Therefore, accurately determining the ignition timing of the upper RF system can prevent the lower RF system from activating before the process chamber is ignited, thus protecting semiconductor processing equipment and improving safety.

[0050] Reference Figure 2 , shows a logic diagram of a control method for semiconductor process equipment in the related art. This method determines the timing of starting the lower RF system by controlling the time interval between starting the upper RF system and the lower RF system. Specifically, the upper RF system is started, and then the lower RF system is started after waiting for the time dt, and the process is continued until the process is completed. It should be noted that Figure 2 Only the processes related to the upper and lower RF system control are given, and the time process will be longer than Figure 2 The process shown is much more complicated. For example, before starting the upper RF system, it is necessary to first ensure that the process gas has been introduced into the process chamber and the process chamber pressure control has been stabilized before starting the power supply of the upper RF system.

[0051] However, the inventors of the present invention discovered through research that different process conditions, such as different gases, different gas pressures, and different upper RF powers, result in different ignition times in the process chamber. Furthermore, plasma ignition exhibits a certain degree of randomness; even with identical process conditions, the time required for ignition varies from one process to the next. Therefore, it is difficult to find a universally applicable wait time dt. Consequently, this method often uses a longer wait time dt to ensure process safety, but this can lead to deviations in process timing.

[0052] Furthermore, under certain extreme process conditions, the upper RF system can easily reach its static impedance point. In this state, there's no plasma inside the process chamber, and all power is applied to the RF coil. In this situation, ignition is impossible, regardless of the waiting time dt. If the lower RF system is then activated, the voltage in the lower RF system will overshoot, potentially damaging it.

[0053] Reference Figure 3 , shows a logic diagram of a control method for semiconductor process equipment in another related art. To avoid the aforementioned method's inability to find a universal waiting time dt that applies to all process conditions, this control method adds a check to determine whether the reflected power is less than a specific value Pth after the upper RF system is activated. Only when the reflected power is less than the specified value Pth will the lower RF system be activated; otherwise, the system waits until the condition that the reflected power is less than Pth is met.

[0054] However, the inventors of this invention have discovered that determining ignition based on reflected power falling below a certain threshold is also unreliable, as it cannot prevent the upper RF system from matching the static impedance of the process chamber under extreme process conditions. Therefore, this control method still cannot guarantee absolute safety of the process chamber.

[0055] Reference Figure 4 , shows a logic diagram of a control method for semiconductor processing equipment in another related art. This method determines ignition by detecting a sudden change in impedance at the back end of a matching device. This method is commonly used in matching algorithms. This method determines plasma ignition based on whether the impedance measured by the matching device changes suddenly at different periods.

[0056] However, the plasma ignition process consists of two stages: 1) ignition to E-mode; 2) transition from E-mode to H-mode. The inventors of the present invention have discovered, as shown in Table 1, that while a plasma glow can be observed when the power is applied to 100W, the impedance in the loaded and non-glow states does not change significantly. However, when the power is applied to 400W, the plasma impedance changes significantly, with a transition between E and H modes. Therefore, the impedance transition point can capture the transition between E and H modes in the process chamber, but it cannot accurately capture the ignition point.

[0057] Table 1

[0058] Incident power (W) Reflected power (W) C1 position C2 position Load impedance Mode Glow state 50 0 829 419 0.25+8.3i No No 100 0 798 421 0.29+8.41i E mode Dark blue 200 0 799 421 0.29+8.41i E mode Bright blue 300 20 787 423 0.3+8.41i E mode Pale pink 400 1 647 453 0.58+7.62i H mode Dark pink 500 1 605 468 0.72+7.3i H mode Dark pink

[0059] Furthermore, matching units typically have built-in current and voltage sensors. The back-end impedance is calculated using the absolute values ​​of the voltage and current measured by these sensors, along with their phase difference. Under normal machine operation, the phase difference between current and voltage is relatively large, making accurate phase calculation difficult. This also results in poor back-end impedance calculation accuracy, making it more difficult to detect impedance transition points.

[0060] In order to solve the problem in the above-mentioned related technologies that it is difficult to find a universal time point for starting the RF system under extreme process conditions, and that it is impossible to accurately capture the time point of plasma ignition, the embodiment of the present invention proposes a method for determining plasma ignition using a sudden change in current or voltage, and a method for controlling semiconductor process equipment based on plasma ignition. The embodiment of the present invention determines the sudden change in current or voltage by monitoring the rate of change of the electrical parameters of the RF coil, that is, the rate of change of current or voltage, and thereby captures the starting time point of plasma ignition, thereby ensuring that the RF system is started after plasma ignition, thereby improving the control efficiency of semiconductor process equipment and improving the safety of semiconductor process equipment. Among them, the rate of change of the electrical parameters of the RF coil is determined by the voltage value or current value detected by the sensor of the semiconductor process equipment, so that the accuracy of determining plasma ignition is higher. The following is combined with Figures 5-13 The embodiments of the present invention are described in further detail.

[0061] Reference Figure 5 , shows an equivalent circuit diagram of a semiconductor process equipment according to an embodiment of the present invention. Taking the ICP machine as an example, the embodiment of the present invention can equate the entire upper electrode system of the ICP machine to a transformer model. The matcher shown in the figure is an L-type network matcher, which is used to match the impedance between the signal source and the load to achieve maximum power transmission and minimum reflection loss. Among them, L is the inductance in the matching network, C1 and C2 are matching capacitors, and are tuning capacitors for achieving matching. In the back-end ICP upper electrode model, R1 is the equivalent ohmic resistance of the RF coil, M is the mutual inductance between the RF coil and the plasma in the process chamber, and R2 is the resistance of the plasma in the process chamber. L1 is the inductance of the ICP RF coil, and L2 is the inductance of the plasma in the process chamber. According to the transformer model, Z can be obtained load The impedance of the point is:

[0062]

[0063] Among them, Z m is the transformer mutual inductance impedance seen by the source side, Z L2An inductive reactance equivalent to the plasma in the process chamber. Depending on the size of the process chamber, most plasma inductances are about 0.25uH. During the plasma ignition process, the process chamber goes through a process from no plasma to plasma formation, and R2 can vary from 1e6Ω to a few Ω.

[0064] Referring to Figure 6 , a graph of the plasma resistance variation of a semiconductor process equipment according to an embodiment of the present application is shown. Z load The real and imaginary parts of the point impedance vary with the plasma resistance R2 in the process chamber as follows: as the plasma ignites, Z load The real part of Z load The imaginary part of Z Figure 6 It can also be seen that during the plasma ignition process, there is no sudden jump in impedance. Therefore, the method of detecting the jump in the impedance at the back end of the matching network in the related art mentioned above cannot accurately capture the plasma ignition point.

[0065] Referring to Figure 7 , a graph of the variation of the capacitance matching path of a semiconductor process equipment according to an embodiment of the present application is shown. The rightmost curve in the graph is the starting point of the matching path, and as the plasma ignites, the values of the capacitances C1 and C2 vary according to the matching path to the left. When the impedance value of the matching network is equal to the impedance value of the radio frequency power of the upper electrode system, the capacitances C1 and C2 reach the end point on the matching path, and the end point of the matching path is the capacitance value corresponding to the capacitances C1 and C2 respectively when the reflected power of the upper electrode system is zero. At the end point of the matching path, the radio frequency power is entirely used to generate plasma.

[0066] Referring to Figure 8 , a graph of the variation of the radio frequency coil current with the plasma resistance of a semiconductor process equipment according to an embodiment of the present application is shown. As the plasma ignites, the current through the resistance R1 or the capacitance C2 gradually decreases from right to left. Assuming that the capacitances C1 and C2 are matched according to the path shown in Figure 7 , according to the equivalent circuit of Figure 5 , the current variation curve through the capacitance C2 can be calculated as shown in Figure 8 . It can be seen from Figure 8 that there is a sudden change point of the current during the plasma ignition process, and therefore this characteristic can be used to determine whether the plasma ignites.

[0067] Referring to Figure 9, shows a flowchart of a method for determining plasma ignition according to an embodiment of the present invention, the method is used for semiconductor process equipment, the semiconductor process equipment includes a radio frequency coil, and the method may specifically include the following steps:

[0068] Step 201: After applying radio frequency power to the radio frequency coil, monitor the rate of change of the electrical parameters of the radio frequency coil or the rate of change of the voltage across the radio frequency coil.

[0069] In an embodiment of the present invention, after applying RF power to the RF coil, that is, after the upper RF system is activated, the rate of change of the RF coil's electrical parameters can be monitored. By observing the time when the rate of change of the electrical parameters suddenly changes, the plasma ignition start point can be accurately captured. This ensures that the lower RF system is activated immediately after plasma ignition. This improves the efficiency of the machine control system while avoiding the generation of high bias voltage and damage to the lower electrode system caused by activating the lower RF system in the absence of plasma. The rate of change of the electrical parameters can include the rate of change of the current flowing through the RF coil or the rate of change of the voltage across the RF coil.

[0070] In one embodiment, the step of monitoring the rate of change of the electrical parameters of the radio frequency coil may include the following sub-steps:

[0071] Sub-step S11, collecting the current value flowing through the radio frequency coil;

[0072] In one embodiment, the semiconductor process equipment includes a matcher disposed between an RF power supply and the RF coil, the matcher includes a current sensor connected in series with the RF coil, and collecting the current value flowing through the RF coil may include: obtaining the current value of the current flowing through the RF coil collected by the current sensor.

[0073] In an embodiment of the present invention, the semiconductor process equipment may be provided with a matcher connected to the RF coil. The matcher may include a current sensor connected in series with the RF coil. The current value of the current flowing through the RF coil may be collected by the current sensor.

[0074] In one embodiment, the RF coil includes an inner RF coil and an outer RF coil, and monitoring the rate of change of an electrical parameter of the RF coil may include: determining a rate of change of a current flowing through the inner RF coil; and / or determining a rate of change of a current flowing through the outer RF coil.

[0075] Reference Figure 10, shows an internal network diagram of a matcher for a semiconductor process equipment according to an embodiment of the present invention. In order to control the current ratio between the inner and outer RF coils, two current sensors are present at the output end of the matcher, connected to the inner and outer RF coils, respectively, to detect the current in the inner and outer RF coils. Capacitors C3 and C4 are used to adjust the ratio of the current value of the inner RF coil to the current value of the outer RF coil. During the upper electrode ignition phase, C3 and C4 are usually kept stationary. The currents detected by the two current sensors change synchronously, so the current change detected by any current sensor can be used to equate the change in the current flowing through capacitor C2.

[0076] Sub-step S12: determining a rate of change of the current flowing through the radio frequency coil according to the current value and a sampling time corresponding to the current value.

[0077] In an embodiment of the present invention, the rate of change of the current flowing through the RF coil may be determined based on the current value and the sampling time corresponding to the current value. Specifically, the rate of change of the current flowing through the RF coil may be expressed by the following formula:

[0078]

[0079] Where I is the current value flowing through the RF coil, t is the sampling time corresponding to the current value, and L is the rate of change of the current flowing through the RF coil.

[0080] In one embodiment, the step of monitoring the rate of change of the electrical parameters of the radio frequency coil may include the following sub-steps:

[0081] Sub-step S21, collecting voltage values ​​across the radio frequency coil;

[0082] In one embodiment, the semiconductor process equipment includes a matcher arranged between an RF power supply and the RF coil, the matcher includes a voltage sensor connected in series with the RF coil, and collecting the voltage value across the RF coil may include: obtaining the voltage value across the RF coil collected by the voltage sensor.

[0083] In an embodiment of the present invention, the semiconductor process equipment may be provided with a matcher connected to the RF coil. The matcher may include a voltage sensor connected in series with the RF coil. The voltage value across the RF coil may be collected by the voltage sensor.

[0084] In one embodiment, the RF coil includes an inner RF coil and an outer RF coil, and monitoring the rate of change of an electrical parameter of the RF coil may include: determining a rate of change of a voltage across the inner RF coil; and / or determining a rate of change of a voltage across the outer RF coil.

[0085] ReferenceFigure 10 , showing an internal network diagram of a matching device in a semiconductor process equipment according to an embodiment of the present invention. In an optional embodiment, the two current sensors may also be two voltage sensors, connected to the inner RF coil and the outer RF coil, respectively, to detect the voltage across the inner RF coil and the outer RF coil.

[0086] Sub-step S22 : determining a voltage change rate across the radio frequency coil according to the voltage value and a sampling time corresponding to the voltage value.

[0087] In the embodiment of the present invention, the voltage change rate across the RF coil may be determined based on the voltage value and the sampling time corresponding to the voltage value. Specifically, the voltage change rate across the RF coil may be expressed by the following formula:

[0088]

[0089] Wherein, U is the voltage value across the RF coil, t is the sampling time corresponding to the voltage value, and L is the rate of change of the voltage across the RF coil.

[0090] Step 202 : When the ratio of the electrical parameter change rate detected at the current moment to the electrical parameter change rate detected at the previous moment exceeds a preset ratio threshold or the difference exceeds a preset difference threshold, it is determined that the plasma has ignited.

[0091] In an embodiment of the present invention, when the ratio of the electrical parameter change rate detected at the current moment to the electrical parameter change rate detected at the previous moment exceeds a preset ratio threshold, or the difference between the electrical parameter change rate detected at the current moment and the electrical parameter change rate detected at the previous moment exceeds a preset difference threshold, it can be determined that plasma ignition has occurred. Figure 5 As shown in the equivalent circuit diagram of the semiconductor process equipment, R1 represents the equivalent ohmic resistance of the RF coil, R2 represents the resistance of the plasma, L1 represents the inductance of the RF coil, and L2 represents the inductance of the plasma. Mutual inductance occurs between the RF coil and the plasma. When plasma is generated, the resistance of the plasma decreases, causing the current in the RF coil to also decrease. Plasma ignition can be confirmed when a sudden change in the RF coil current is detected.

[0092] Specifically, the ratio of the electrical parameter change rate detected at the current moment to the electrical parameter change rate detected at the previous moment exceeds the preset ratio threshold value can be expressed by the following formula:

[0093]

[0094]

[0095] Among them, N is a preset ratio threshold, which can be a positive integer from 3 to 100. Those skilled in the art can set the preset ratio threshold to any value from 3 to 100 based on the concept of the present invention, and the present invention does not limit this.

[0096] In an embodiment of the present invention, after applying RF power to the RF coil, the rate of change of the RF coil's electrical parameters can be monitored. Plasma ignition is determined when the ratio of the current rate of change to the previous rate of change exceeds a preset ratio threshold, or the difference exceeds a preset difference threshold. The rate of change of the electrical parameters may include the rate of change of the current flowing through the RF coil or the rate of change of the voltage across the RF coil. In this embodiment of the present invention, plasma ignition is determined based on a sudden change in the rate of change of the RF coil's electrical parameters. This allows accurate determination of the ignition timing of semiconductor process equipment based on plasma ignition, avoiding the need to activate the RF system before ignition of the semiconductor process equipment, and improving the safety of the semiconductor process equipment.

[0097] Reference Figure 11 , shows a flowchart of a method for controlling a semiconductor process device according to an embodiment of the present invention, wherein the semiconductor process device includes a radio frequency coil and a wafer carrier, and the method includes:

[0098] Step 301: applying a first radio frequency power to the radio frequency coil;

[0099] In an embodiment of the present invention, semiconductor processing equipment, such as an etcher, may include a radio frequency coil and a wafer carrier, wherein the radio frequency coil is located in an upper radio frequency system of the etcher, and the wafer carrier is located in a lower radio frequency system of the etcher. In this embodiment of the present invention, a first radio frequency power may be applied to the radio frequency coil to activate the upper radio frequency system.

[0100] Step 302, using the method for determining plasma ignition as described above, to determine whether the plasma has ignited;

[0101] Step 303: After the plasma is ignited, a second radio frequency power is applied to the bias electrode of the wafer supporting device.

[0102] In an embodiment of the present invention, after plasma ignition, a second RF power can be applied to the bias electrode of the wafer carrier to activate the lower RF system to execute the process flow. In this embodiment of the present invention, after applying the first RF power to the RF coil, the method for determining plasma ignition described in steps 201 and 202 can be used to determine whether the plasma has ignited. This ensures that the lower RF system is activated immediately after plasma ignition. This improves the efficiency of the tool control system while avoiding the generation of high bias voltage and damage to the lower electrode system caused by activating the lower RF system in the absence of plasma.

[0103] Referring to Figure 12 , a logic diagram of another control method of a semiconductor process equipment provided by the embodiment of the present application is shown, in order to enable those skilled in the art to better understand the embodiment of the present application, the following will be described by taking Figure 12 the embodiment of the present application as an example:

[0104] (1) applying radio frequency power to the radio frequency coil to start the upper radio frequency system;

[0105] (2) collecting the current value of the current flowing through the radio frequency coil, determining the current change rate of the current flowing through the radio frequency coil, and determining whether the current change rate exceeds the preset threshold according to the ratio of the current change rate at the current sampling time to the current change rate at the last sampling time;

[0106] (3) when the current change rate at the current sampling time exceeds the preset threshold, determining that the plasma ignites, and applying radio frequency power to the radio frequency electrode of the wafer carrier device to start the lower radio frequency system;

[0107] (4) starting the process.

[0108] In the embodiment of the present application, radio frequency power can be applied to the radio frequency coil of the semiconductor process equipment to start the upper radio frequency system, and after the upper radio frequency system is started, the current flowing through the inner and outer radio frequency coils or the voltage of the inner and outer radio frequency coils is collected by the current voltage sensor to determine the current change rate of the current flowing through the radio frequency coil, when the current change rate exceeds the preset threshold, it is determined that the plasma ignites, and after the plasma ignites, radio frequency power is applied to the radio frequency electrode of the wafer carrier device to start the lower radio frequency system. The embodiment of the present application can accurately determine the ignition time of the upper radio frequency system through the sudden change of the current change rate caused by the plasma ignition in the system, and start the lower radio frequency system after the upper radio frequency system ignites, which avoids starting the lower radio frequency system before the upper radio frequency system ignites, and improves the safety of the semiconductor process equipment.

[0109] It should be noted that for the method embodiment, in order to simply describe, it is expressed as a series of action combinations, but those skilled in the art should know that the embodiment of the present application is not limited by the described action sequence, because according to the embodiment of the present application, certain steps can be performed in other order or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the involved actions are not necessarily required by the embodiment of the present application.

[0110] Referring to Figure 13, shows a structural block diagram of a semiconductor process equipment provided by an embodiment of the present invention, wherein the semiconductor process equipment 400 includes a process chamber 401, a radio frequency coil 402, a wafer carrier 403, a first radio frequency power supply 404 electrically connected to the radio frequency coil, and a second radio frequency power supply 405 electrically connected to a bias electrode of the wafer carrier. The wafer carrier 403 is disposed in the process chamber 401; and

[0111] The controller 406 includes at least one memory and at least one processor. A computer program is stored in the controller 406. When the computer program is executed by the processor, the steps of the method for determining plasma ignition as described in any one of the above items are implemented, or the steps of the control method of the semiconductor process equipment as described above are implemented.

[0112] As for the semiconductor process equipment embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0113] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0114] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, apparatus, or computer program products. Thus, embodiments of the present invention may take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware. Furthermore, embodiments of the present invention may take the form of a computer program product implemented on one or more machine-readable media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0115] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the process in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0116] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0117] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0118] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0119] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or terminal device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or terminal device that includes the element.

[0120] The above is a detailed introduction to a method for determining plasma ignition and a method for controlling semiconductor process equipment provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A control method for semiconductor process equipment, wherein the semiconductor process equipment includes a radio frequency coil and a wafer carrier, the method comprising: applying a first radio frequency power to the radio frequency coil; After a first RF power is applied to the RF coil, a plasma resistance gradually decreases, and an imaginary impedance part at an input end of the RF coil gradually decreases as the plasma resistance gradually decreases, so that a current flowing through the RF coil gradually decreases, and a rate of change of an electrical parameter of the RF coil is monitored, where the rate of change of the electrical parameter includes a rate of change of the current flowing through the RF coil or a rate of change of the voltage across the RF coil; When the ratio of the electrical parameter change rate detected at the current moment to the electrical parameter change rate detected at the previous moment exceeds a preset ratio threshold or the difference exceeds a preset difference threshold, the plasma ignition is determined, and the preset ratio threshold is any value between 3 and 100; After the plasma is ignited, a second radio frequency power is applied to the bias electrode of the wafer supporting device.

2. The method according to claim 1, characterized in that The monitoring of the rate of change of the electrical parameters of the radio frequency coil includes: collecting a current value flowing through the radio frequency coil; A rate of change of the current flowing through the radio frequency coil is determined according to the current value and a sampling time corresponding to the current value.

3. The method according to claim 1, characterized in that The monitoring of the rate of change of the electrical parameters of the radio frequency coil includes: collecting voltage values ​​across the radio frequency coil; A voltage change rate across the radio frequency coil is determined according to the voltage value and a sampling time corresponding to the voltage value.

4. The method according to claim 2, characterized in that The radio frequency coil includes an inner radio frequency coil and an outer radio frequency coil, and monitoring the rate of change of an electrical parameter of the radio frequency coil includes: determining a rate of change of current flowing through the inner RF coil; and / or, A rate of change of current through the external radio frequency coil is determined.

5. The method according to claim 3, characterized in that The radio frequency coil includes an inner radio frequency coil and an outer radio frequency coil, and monitoring the rate of change of an electrical parameter of the radio frequency coil includes: determining a rate of change of voltage across the inner RF coil; and / or, The rate of change of voltage across the external radio frequency coil is determined.

6. The method according to claim 2 or 4, characterized in that The semiconductor process equipment includes a matcher disposed between a radio frequency power source and the radio frequency coil, the matcher includes a current sensor connected in series with the radio frequency coil, and collecting a current value flowing through the radio frequency coil includes: A current value of the current flowing through the radio frequency coil collected by the current sensor is obtained.

7. The method according to claim 3 or 5, characterized in that The semiconductor process equipment includes a matcher disposed between a radio frequency power source and the radio frequency coil, the matcher includes a voltage sensor connected in series with the radio frequency coil, and collecting the voltage value across the radio frequency coil includes: The voltage value across the radio frequency coil collected by the voltage sensor is obtained.

8. A semiconductor process equipment, characterized in that: include: A process chamber, a radio frequency coil, a wafer carrier, a first radio frequency power supply electrically connected to the radio frequency coil, and a second radio frequency power supply electrically connected to the bias electrode of the wafer carrier, wherein the wafer carrier is disposed in the process chamber; as well as A controller includes at least one memory and at least one processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the control method of a semiconductor process equipment according to any one of claims 1 to 7 are implemented.

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