Pulse voltage generation circuit and semiconductor process device

Abstract

The present application provides a pulse voltage generation circuit and a semiconductor process device, applied to the technical field of semiconductor manufacturing. The circuit comprises an energy storage circuit and a switch unit; connection points between the energy storage circuit and first controllable switches in the switch unit are used for outputting an operation pulse voltage; turn-on states of the first controllable switches in the switch unit are controlled by a controller; the first controllable switches are in a parallel relationship; turn-on time periods of the first controllable switches do not overlap each other, and the turn-on time periods of two first controllable switches which are adjacent in a turn-on sequence are spaced by a preset duration; and the first controllable switches are turned on in sequence according to the described mode, so as to output the operation pulse voltage, the pulse frequency of the operation pulse voltage being the sum of switching frequencies of the turn-on states of the first controllable switches. By arranging the plurality of first controllable switches, the pulse frequency of the operation pulse voltage can be effectively improved, thereby improving the control effect of unimodal IEDF, and satisfying actual process requirements.

Description

Pulse voltage generating circuit and semiconductor process equipment Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a pulse voltage generating circuit and semiconductor process equipment. Background Art

[0002] Low-pressure, low-temperature, weakly ionized glow discharge plasmas are widely used in integrated circuit manufacturing, particularly in processes such as plasma etching and plasma-enhanced chemical vapor deposition. As integrated circuits continue to increase in density and demand for advanced processes such as high aspect ratios and high selectivity becomes increasingly important, precise and independent control of the plasma's unimodal ion energy distribution (IEDF) becomes increasingly important.

[0003] FIG1 shows a pulse voltage generating circuit in the prior art. The circuit uses a switch tube T1 and a switch tube T2 to form a half-bridge circuit. By alternately turning on the two switch tubes and processing them through the subsequent circuit, an operating pulse voltage for controlling ion distribution can be output.

[0004] As shown in Figure 1, the pulse frequency of the operating pulse voltage output by this circuit is consistent with the pulse frequency of the driving pulse voltage of the switching tube. The voltage amplitude of the operating pulse voltage is the DC voltage amplitude that directly acts on the switching tube. Therefore, the pulse frequency and voltage amplitude of the operating pulse voltage output by this circuit directly affect the losses of the switching tube. That is, the higher the pulse frequency, the greater the switching tube losses. At the same time, the higher the voltage amplitude, the greater the switching tube losses. In order to achieve high voltage output while meeting the switching tube loss requirements, the existing technology can only output low-frequency operating pulse voltage, resulting in poor single-peak IEDF control effect. The single-peak IEDF in the existing technology contains a large number of low-energy peaks, which is far from the ideal single-peak IEDF and seriously affects the actual process effect. Summary of the Invention

[0005] In view of this, the present application is committed to providing a pulse voltage generating circuit and semiconductor process equipment, which, on the basis of meeting the switching loss requirements and high voltage output, increases the pulse frequency of the operating pulse voltage, improves the single-peak IEDF control effect, and meets actual process requirements.

[0006] In a first aspect, the present application provides a pulse voltage generating circuit for semiconductor process equipment, the circuit comprising: a tank circuit and a switch unit, the switch unit comprising a plurality of first controllable switches, wherein:

[0007] The input end of the energy storage circuit is used to be connected to a DC power supply, the output end of the energy storage circuit is respectively connected to the input end of each first controllable switch, and the output end of each first controllable switch is used to be grounded;

[0008] The connection point between the energy storage circuit and each of the first controllable switches is used to output an operating pulse voltage;

[0009] The control end of each of the first controllable switches is used to be connected to the controller;

[0010] Each of the first controllable switches is used to be turned on in sequence under the control of the controller to output the operating pulse voltage;

[0011] The conduction periods of the first controllable switches do not overlap with each other, and the conduction periods of two first controllable switches that are adjacent in conduction sequence are separated by a preset time interval;

[0012] The energy storage circuit is used to store electrical energy when any of the first controllable switches is turned on, and release the electrical energy within the preset time period.

[0013] In an optional embodiment, the controller is configured as follows:

[0014] According to preset driving pulse voltage parameters, a driving pulse voltage is output to each of the first controllable switches respectively, wherein the driving pulse voltage is used to control the conduction state of the first controllable switch.

[0015] In an optional embodiment, the pulse voltage generating circuit provided in the first aspect of the present application further includes: an oscillation suppression circuit, wherein:

[0016] The input end of the oscillation suppression circuit is connected to the energy storage circuit and the connection point of each of the first controllable switches, and the output end of the oscillation suppression circuit is used to output the operating pulse voltage;

[0017] The oscillation suppression circuit is used to suppress voltage fluctuations of the operating pulse voltage.

[0018] In an optional embodiment, the pulse voltage generating circuit provided in the first aspect of the present application further includes: a parameter acquisition circuit, wherein:

[0019] The parameter acquisition circuit is used to collect the actual operating pulse voltage at a preset sampling point, wherein the preset sampling point includes at least one of the input end of the oscillation suppression circuit, the output end of the oscillation suppression circuit, and a bias electrode, and the bias electrode is located in the wafer carrier of the semiconductor process equipment;

[0020] The controller is configured to adjust the DC voltage output by the DC power supply and / or the conduction process of each of the first controllable switches according to the actual operating pulse voltage.

[0021] In an optional embodiment, the pulse voltage generating circuit provided in the first aspect of the present application further includes: a protection circuit, wherein:

[0022] The first connection end of the protection circuit is used to be connected to the output end of the DC power supply, and the second connection end of the protection circuit is connected to the input end of the energy storage circuit;

[0023] The controller is connected to the control end of the protection circuit;

[0024] The controller is configured to control the protection circuit to disconnect the DC power supply from the energy storage circuit and release the electric energy stored in the energy storage circuit when the voltage amplitude of the actual operating pulse voltage is greater than a first preset voltage threshold.

[0025] In an optional implementation, the protection circuit includes: a second controllable switch, a third controllable switch, and a first resistor, wherein:

[0026] The input terminal of the second controllable switch serves as the first connection terminal of the protection circuit;

[0027] A connection point between the output terminal of the second controllable switch and the input terminal of the third controllable switch serves as a second connection terminal of the protection circuit;

[0028] The output end of the third controllable switch is connected to one end of the first resistor, and the other end of the first resistor is grounded;

[0029] The control ends of the second controllable switch and the third controllable switch are respectively connected to the controller.

[0030] In an optional embodiment, the energy storage circuit includes: an energy storage inductor and a voltage stabilizing capacitor, wherein:

[0031] The first end of the energy storage inductor is connected to the first end of the voltage stabilizing capacitor, and the second end of the energy storage inductor serves as the output end of the energy storage circuit;

[0032] The second end of the voltage stabilizing capacitor is used for grounding;

[0033] The connection point between the energy storage inductor and the voltage stabilizing capacitor serves as the input end of the energy storage circuit.

[0034] In a second aspect, the present application provides a semiconductor process device, comprising: a process chamber, a controller, and a pulse voltage generating circuit as described in any one of the first aspects of the present application, wherein:

[0035] A wafer carrying device is provided in the process chamber, and a bias electrode is provided in the wafer carrying device;

[0036] The controller is electrically connected to the control end of each first controllable switch of the pulse voltage generating circuit;

[0037] The output end of the pulse voltage generating circuit is connected to the bias electrode;

[0038] The controller is used to control the pulse voltage generating circuit to output an operating pulse voltage to the bias electrode to control ion energy distribution.

[0039] In an optional embodiment, the semiconductor process equipment provided in the second aspect of the present application further includes: a radio frequency coil, a matcher, and a radio frequency power supply, wherein:

[0040] The RF power supply is used to apply RF power to the RF coil through the matching device to excite plasma in the process chamber;

[0041] The controller is also electrically connected to the RF power supply to control the output power of the RF power supply.

[0042] In an optional embodiment, the semiconductor process equipment provided in the second aspect of the present application further includes: an ion current detector, wherein:

[0043] The ion current detector is used to collect the actual ion current bombarding the wafer placed on the wafer carrier, and the actual ion current is used to characterize the actual ion flux;

[0044] The controller is further configured to adjust the radio frequency power of the radio frequency power supply until a deviation between the actual ion flux and the target ion flux is within a preset flux deviation range.

[0045] In an optional embodiment, the controller is further configured to perform the following steps:

[0046] Obtaining an actual operating pulse voltage at a preset sampling point in the pulse voltage generating circuit;

[0047] determining actual ion energy according to the actual operating pulse voltage;

[0048] The DC voltage output by the DC power supply connected to the pulse voltage generating circuit and / or the conduction process of each first controllable switch in the pulse voltage generating circuit are adjusted so that the energy distribution of the actual ion energy is a single-peak distribution.

[0049] In an optional embodiment, the pulse voltage generating circuit includes a protection circuit and an energy storage circuit, and the controller is further configured to perform the following steps:

[0050] If the voltage amplitude of the actual operating pulse voltage is greater than a first preset voltage threshold, controlling the protection circuit to disconnect the DC power supply from the energy storage circuit and release the electric energy stored in the energy storage circuit;

[0051] Adjusting the DC voltage output by the DC power supply and / or the conduction process of each of the first controllable switches until the voltage amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold;

[0052] The protection circuit is controlled to connect the DC power supply and the energy storage circuit.

[0053] Based on the above, the pulse voltage generating circuit provided in the present application includes a tank circuit and a switch unit. The connection point between the tank circuit and each first controllable switch in the switch unit is used to output an operating pulse voltage. The conduction state of each first controllable switch in the switch unit is controlled by a controller. Since the first controllable switches are connected in parallel, the conduction of any first controllable switch causes the output end of the tank circuit to be grounded, thereby storing electrical energy. Accordingly, since the conduction periods of the first controllable switches do not overlap with each other (i.e., they are not turned on at the same time) and the conduction periods of two first controllable switches adjacent in the conduction sequence are separated by a preset time, each first controllable switch is turned off during the preset time, and the tank circuit releases electrical energy. Based on this setting, when any first controllable switch is turned on, the pulse voltage generating circuit outputs a low level, and the time corresponding to the aforementioned conduction period is the duration of the low level. Accordingly, when all first controllable switches are turned off, the pulse voltage generating circuit outputs a high level, and the aforementioned preset time is the duration of the high level. Each first controllable switch is turned on in sequence in the above manner to output the operating pulse voltage.

[0054] It can be seen from this that the pulse frequency of the operating pulse voltage is the sum of the on-state switching frequencies of each first controllable switch. By providing multiple first controllable switches, the pulse frequency of the operating pulse voltage can be effectively increased. For the first controllable switches, when the pulse frequency of the operating pulse voltage is constant, the pulse frequency is shared by each first controllable switch, and the on-state switching frequency of each first controllable switch is effectively reduced, thereby effectively reducing switching losses. At the same time, because the energy storage circuit can store electrical energy, when it releases electrical energy within a preset time period, it will be superimposed with the electrical energy output by the DC power supply, thereby effectively increasing the voltage amplitude of the operating pulse voltage. Therefore, this application can increase the pulse frequency of the operating pulse voltage while meeting the switching loss requirements and high voltage output, thereby improving the single-peak IEDF control effect and meeting actual process requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0056] FIG1 is a circuit topology diagram of a pulse voltage generating circuit in the prior art.

[0057] FIG2 is a circuit topology diagram of a pulse voltage generating circuit provided in an embodiment of the present application.

[0058] FIG3 is a schematic diagram of a control timing sequence corresponding to the pulse voltage generating circuit provided by the embodiment shown in FIG2 .

[0059] 4a-4c are schematic diagrams showing the simulation control effects of pulse voltage generation by using the pulse voltage generating circuit provided in an embodiment of the present application.

[0060] 5a-5b are schematic diagrams showing actual control effects of pulse voltage generation by using the pulse voltage generating circuit provided in an embodiment of the present application.

[0061] FIG6 is a circuit topology diagram of another pulse voltage generating circuit provided in an embodiment of the present application.

[0062] FIG. 7 is a schematic diagram of a control timing sequence corresponding to the pulse voltage generating circuit provided in the embodiment shown in FIG. 6 .

[0063] FIG8 is a circuit topology diagram of another pulse voltage generating circuit provided in an embodiment of the present application.

[0064] FIG9 is a structural block diagram of a pulse voltage generating circuit provided in an embodiment of the present application.

[0065] FIG10 is a schematic structural diagram of an ion current detector provided in an embodiment of the present application.

[0066] FIG11 is a flow chart of a pulse voltage generating method provided in an embodiment of the present application.

[0067] FIG12 is a flow chart of another pulse voltage generating method provided in an embodiment of the present application.

[0068] FIG13 is a flow chart of another pulse voltage generating method provided in an embodiment of the present application.

[0069] FIG14 is a flow chart of another pulse voltage generating method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0070] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0071] As mentioned above, low-pressure, low-temperature, weakly ionized glow discharge plasmas are widely used in integrated circuit manufacturing, particularly in processes such as plasma etching and plasma-enhanced chemical vapor deposition. However, with the increasing integration density of integrated circuits and the demand for advanced processes such as high aspect ratios and high selectivity, the bimodal ion energy distribution (IEDF) control used in the etching process has become difficult to meet practical application requirements. Accurate and independent control of the plasma's single-peak IEDF has become increasingly important.

[0072] Figure 1 shows a pulse voltage generating circuit in the prior art. The circuit uses a switch tube T1 and a switch tube T2 to form a half-bridge circuit. The drain of the switch tube T1 is connected to the DC high voltage Vbus, the source of the switch tube T1 is connected to the drain of the switch tube T2, and the source of the switch tube T2 is grounded. The driving voltage between the gate and source of the two switch tubes is controlled to achieve the switching of the conduction state of the switch tubes. Then, the two switch tubes are alternately turned on and, after being processed by the subsequent circuit, an operating pulse voltage for controlling ion distribution is output.

[0073] As shown in Figure 1, the pulse frequency of the operating pulse voltage output by this circuit is consistent with the pulse frequency of the driving pulse voltage of the switching tube. The voltage amplitude of the operating pulse voltage is the DC voltage amplitude that directly acts on the switching tube. Therefore, the pulse frequency and voltage amplitude of the operating pulse voltage output by this circuit directly affect the loss of the switching tube. That is, the higher the pulse frequency, the greater the loss of the switching tube. At the same time, the higher the voltage amplitude, the greater the loss of the switching tube. In order to achieve high voltage output while meeting the loss requirements of the switching tube, the existing technology can only output low-frequency operating pulse voltage. Because the frequency is not high enough, the plasma bombarding the wafer surface (i.e., ion current) will cause a significant increase in the wafer surface potential. This will cause the generated ion energy distribution to be widely broadened, making it difficult to meet the requirements of advanced processes such as high aspect ratio and high selectivity.

[0074] Although there are other technical solutions in actual applications, a current compensation circuit is added to the circuit shown in Figure 1 to add a negative voltage slope at one end to the output operating pulse voltage. Although this can improve the single-peak IEDF control effect to a certain extent, it does not solve the fundamental problem of the low pulse frequency of the operating pulse voltage, and the actual application effect is still unsatisfactory. At the same time, due to the addition of a new circuit, the overall circuit structure and control process are more complicated, the controller logic overhead is greater, and the overall cost of the circuit is also significantly increased.

[0075] In order to solve the above technical problems, the present application provides a pulse voltage generating circuit, which increases the pulse frequency of the operating pulse voltage on the basis of meeting the switching loss requirements and high voltage output, thereby improving the single-peak IEDF control effect and meeting actual process requirements.

[0076] The pulse voltage generating circuit provided in the present application is applied to semiconductor process equipment. In practical applications, the semiconductor process equipment can be an ICP (Inductively Coupled Plasma) etcher, a CCP (Capacitively Coupled Plasma) etcher or a PECVD (Plasma Enhanced Chemical Vapor Deposition) etcher. Based on this, referring to FIG2 , FIG2 takes an ICP etcher as an example to illustrate the application scenario of the pulse voltage generating circuit provided in the present application. The semiconductor process equipment includes a process chamber 140, a controller 70, an RF power supply 90, an impedance matching circuit 100 and an upper electrode. For the ICP etcher, the upper electrode includes a coupling coil 110, the output end of the RF power supply 90 is connected to the impedance matching circuit 100, and the impedance matching circuit 100 is connected to the coupling coil 110. After the RF power supply 90 is started, the RF power can be applied to the coupling coil 110 through the impedance matching circuit 100, and plasma is generated inside the process chamber 140. A wafer carrier 130 is disposed within the process chamber 140, positioned opposite the upper electrode. The wafer carrier 130 may include, for example, an electrostatic chuck or a mechanical chuck. A bias electrode 40 is disposed within the wafer carrier 130. The pulse voltage generating circuit provided herein is used to provide a bias voltage to the bias electrode 40 of the wafer carrier 130 within the process chamber 140. As shown in FIG2 , the pulse voltage generating circuit includes a tank circuit 20 and a switch unit 30.

[0077] As shown in Figure 2, in a possible embodiment, the energy storage circuit 20 includes an energy storage inductor L1 and a voltage-stabilizing capacitor C1, wherein the first end of the energy storage inductor L1 is connected to the first end of the voltage-stabilizing capacitor C1, and the connection point between the energy storage inductor L1 and the voltage-stabilizing capacitor C1 serves as the input end of the energy storage circuit 20 and is connected to the output end of the DC power supply 10. The second end of the energy storage inductor L1 serves as the output end of the energy storage circuit 20 and is connected to the input end of the switch unit 30. The second end of the voltage-stabilizing capacitor C1 is grounded. In practical applications, the voltage-stabilizing capacitor C1 is generally selected as a μF capacitor to maintain the stability of the output voltage to the subsequent circuit. The energy storage inductor L1 is generally selected as a μH inductor to store or release energy. The specific selection of the voltage-stabilizing capacitor C1 and the energy storage inductor L1 needs to be determined in combination with factors such as the specific application scenario of the control circuit and the circuit design parameters. This application does not limit the specific selection of the energy storage inductor L1 and the voltage-stabilizing capacitor C1.

[0078] As a preferred embodiment, the energy storage circuit 20 provided in this embodiment is further provided with a diode D1. Through the unidirectional conduction function of the diode D1, the current direction on the energy storage inductor L1 can be ensured to be constant, that is, it can only flow from the DC power supply 10 side to the switching unit 30 side. At the same time, LC oscillation can also be avoided.

[0079] Furthermore, the switch unit 30 includes multiple first controllable switches, namely, at least two first controllable switches. In the embodiment shown in FIG2 , the switch unit 30 includes two first controllable switches (i.e., a first controllable switch S1 and a first controllable switch S2). The input end of each first controllable switch is connected to the output end of the energy storage circuit 20 as the input end of the switch unit 30. At the same time, the output end of each first controllable switch is grounded. Based on the above connection relationship, it can be seen that the first controllable switches in the switch unit 30 are connected in parallel. When any first controllable switch is turned on, the switch unit 30 is turned on, thereby grounding the energy storage circuit 20. Correspondingly, when all first controllable switches are turned off, the switch unit 30 is turned off. The connection point between the input end of the switch unit 30 and the output end of the energy storage circuit 20 serves as the output end of the pulse voltage generating circuit and is connected to the bias electrode 40 disposed in the process chamber 140. The control end of each first controllable switch in the switch unit 30 is respectively connected to the controller 70, which can control the conduction state of each first controllable switch.

[0080] It should be noted that in the embodiment shown in Figure 2 and subsequent embodiments, the first controllable switch can be implemented by selecting a switch tube of type Si, SiC or GaN. Of course, other controllable switch tubes that can meet the circuit operation requirements can also be selected, and they will not be elaborated one by one here.

[0081] Based on the above connection relationship, the controller 70 can be a host computer or a slave computer. In this application, it is mainly used to control the conduction state of each first controllable switch in the switch unit 30. The specific conduction state control rule is: each first controllable switch is turned on in sequence, the conduction period of each first controllable switch does not overlap, and the conduction period interval between two first controllable switches with adjacent conduction sequences is a preset time length. It can be understood that the first controllable switches are turned on in sequence, requiring each first controllable switch in the switch unit to be turned on in a preset sequence during the operation of the pulse voltage generating circuit. Taking the first controllable switch S1 and the first controllable switch S2 shown in Figure 2 as an example, the process of turning on the two in sequence is: first controllable switch S1 → first controllable switch S2 → first controllable switch S1 ... and so on, and so on, until the pulse voltage generating circuit stops operating. The conduction periods of the first controllable switches do not overlap with each other, which can ensure that no first controllable switches that are turned on at the same time appear in the switch unit. The conduction periods of two first controllable switches that are adjacent in the conduction sequence are separated by a preset time interval, which is used to ensure that all first controllable switches are turned off within the preset time interval.

[0082] As described above, the first controllable switches in the switch unit 30 are connected in parallel. When the controller 70 controls the first controllable switches to be turned on in sequence, the turning on of any first controllable switch causes the output end of the energy storage circuit 20 to be grounded. At this time, the energy storage circuit 20 stores electrical energy. Accordingly, since the conduction periods of the first controllable switches do not overlap with each other and the conduction periods of two first controllable switches that are adjacent in the conduction sequence are separated by a preset time period, the first controllable switches are all turned off within the preset time period, and the energy storage circuit 20 will release the electrical energy stored in the previous period.

[0083] Based on this setting, when any first controllable switch is turned on, the pulse voltage generating circuit outputs a low level, and the duration corresponding to the aforementioned conduction period is the duration of the low level. Correspondingly, when each first controllable switch is turned off, a high level is output, and the aforementioned preset duration is the duration of the high level, thereby realizing the conversion of the DC voltage output by the DC power supply 10 into a pulse voltage through the switching unit 30. The controller 70 controls each first controllable switch to be turned on in sequence in the above manner, and outputs the operating pulse voltage to the bias electrode 40 through the connection point between the energy storage circuit 20 and each first controllable switch.

[0084] As shown in Figure 2, in a possible embodiment, the control end of the DC power supply 10 is connected to the controller 70, and the controller 70 is also used to control the DC power supply to output a DC voltage. In actual applications, the controller 70 can control the working state of the DC power supply 10, that is, control the DC power supply 10 to output a DC voltage or stop outputting the DC voltage. In a preferred embodiment, the output voltage of the DC power supply 10 is adjustable, and the controller 70 can adjust the amplitude of the DC voltage actually output by the DC power supply 10 according to the actual operating conditions of the circuit and the pulse voltage generation requirements. The output end of the DC power supply 10 is connected to the input end of the energy storage circuit 20, and outputs a DC voltage to the energy storage circuit 20. As for the specific process of the controller 70 controlling the DC power supply 10 to output the DC voltage, it will be expanded in the subsequent content and will not be described in detail here.

[0085] In summary, through the pulse voltage generating circuit provided by this embodiment, the sum of the duration corresponding to the conduction period of the first controllable switch and the preset duration is the pulse period of the operating pulse voltage. Correspondingly, the pulse frequency of the operating pulse voltage is the sum of the conduction state switching frequencies of each first controllable switch. Therefore, by providing multiple first controllable switches, the pulse frequency of the operating pulse voltage can be effectively increased. For the first controllable switches, when the pulse frequency of the operating pulse voltage is constant, the pulse frequency is shared by each first controllable switch, and the conduction state switching frequency of each first controllable switch is effectively reduced, thereby effectively reducing switching losses. At the same time, because the energy storage circuit can store electrical energy, when it releases electrical energy within the preset duration, it will be superimposed with the electrical energy output by the DC power supply, thereby effectively increasing the voltage amplitude of the operating pulse voltage. Therefore, the present application can increase the pulse frequency of the operating pulse voltage on the basis of meeting the switching loss requirements and voltage amplitude requirements, thereby improving the single-peak IEDF control effect and meeting actual process requirements.

[0086] Furthermore, since the pulse frequency of the operating pulse voltage output by the pulse voltage generating circuit provided in the present application is high enough, a good single-peak IEDF control effect can still be achieved without adding other current compensation circuits. Compared with the existing technology, the control process can be simplified, thereby reducing the logical overhead of the controller and effectively reducing the overall cost of the circuit.

[0087] Taking the circuit topology shown in FIG2 as an example, an implementation method of a control signal that can meet the above-mentioned control rules for the conduction state of the first controllable switch is provided. In this embodiment, the switching of the conduction state of each first controllable switch in the switch unit is driven by a pulse voltage, that is, the first controllable switch is controlled to be turned on by the high level of the pulse voltage, and the first controllable switch is controlled to be turned off by the low level of the pulse voltage. In order to distinguish it from the aforementioned operating pulse voltage, this application defines the pulse voltage used to drive the conduction state of the first controllable switch as a driving pulse voltage. In actual applications, according to the requirements for generating the pulse voltage, the controller can be configured with drive pulse voltage parameters, such as the pulse period, duty cycle, and voltage amplitude of the drive pulse voltage. The controller can determine the drive pulse voltage to be output based on the preset drive pulse voltage parameters. After receiving the control instruction, the controller can output the drive pulse voltage to each first controllable switch respectively.

[0088] Furthermore, as mentioned above, the voltage amplitude, pulse frequency, duty cycle and other parameters of the operating pulse voltage ultimately output by the pulse voltage generating circuit are all affected by the switching unit. Therefore, when the parameters of the operating pulse voltage are determined, the driving pulse voltage can also be determined in reverse. This is of great significance in practical applications. This content will be expanded in subsequent content and will not be described in detail here.

[0089] FIG3 shows a control sequence in which the controller controls the switch unit according to a preset driving pulse voltage.

[0090] During the period t0-t1, the first controllable switch S1 is turned on and the first controllable switch S2 is turned off. At this time, the output end of the DC power supply 10 forms a closed loop through the energy storage inductor L1 and the first controllable switch S1. The DC power supply 10 charges the energy storage inductor L1, and the output voltage (i.e., Vout) of the pulse voltage generating circuit is 0V.

[0091] During the period t1-t2 (corresponding to the aforementioned preset duration), both the first controllable switch S1 and the first controllable switch S2 are turned off. The energy storage inductor L1 in the energy storage circuit 20 releases electrical energy, which is superimposed on the electrical energy output by the DC power supply 10, thereby increasing the output voltage amplitude. Simultaneously, due to the action of the voltage-stabilizing capacitor C1, the output voltage amplitude remains substantially constant during the period when both first controllable switches are turned off.

[0092] During the period t2-t3, the first controllable switch S1 is turned off and the first controllable switch S2 is turned on. At this time, the DC power supply 10 forms a closed loop through the energy storage inductor L1 and the first controllable switch S2. The DC power supply 10 continues to charge the energy storage inductor L1. Accordingly, the output voltage of the pulse voltage generating circuit drops to 0V again.

[0093] During the period t3-t4, both first controllable switches S1 and S2 are off, and the DC power supply and energy storage inductor L1 continue to provide a high-amplitude DC voltage. At t4, first controllable switch S1 turns on, while first controllable switch S2 turns off. At this point, both first controllable switches S1 and S2 have completed a drive cycle. By periodically repeating this process, the operating pulse voltage can be output.

[0094] Combined with Figure 3, it can be seen that:

[0095] First, during the time period t0-t4, both the drive pulse voltage of the first controllable switch S1 and the drive pulse voltage of the first controllable switch S2 have one high-level output, while the operating pulse voltage produces two high-level outputs. Therefore, the pulse frequency of the operating pulse voltage is twice the pulse frequency of the drive pulse voltage of the first controllable switch, that is, the pulse frequency of the operating pulse voltage is the sum of the pulse frequencies of the drive pulse voltages of each first controllable switch. Therefore, without increasing the pulse frequency of the controllable switch drive pulse voltage, the pulse frequency of the operating pulse voltage can be significantly increased by providing multiple first controllable switches, thereby effectively reducing the loss of the controllable switch and achieving a high-pulse-frequency operating pulse voltage output.

[0096] Secondly, the voltage amplitude of the operating pulse voltage can be controlled by the switching unit. In the steady state, the voltage amplitude of the operating pulse voltage finally output by the pulse voltage generating circuit can be calculated by the following formula compared with the amplification factor of the DC voltage output by the DC power supply:

[0097] Where N represents the voltage amplification factor;

[0098] M represents the number of first controllable switches in the switch unit;

[0099] t a -t b Indicates the duration that any first controllable switch is in the on state;

[0100] t c -t d Indicates the preset duration of the conduction period interval between two first controllable switches that are adjacent in the conduction sequence.

[0101] For example, the frequency of the driving pulse voltage of the first controllable switch S1 and the first controllable switch S2 is 5MHz, and the duration of the conduction period of any first controllable switch is 80ns, then the pulse frequency of the output operating pulse voltage is 10MHz, and the pulse width (i.e., the duration of the high level) is 20ns. If the DC voltage output by the DC power supply is 100V, then the voltage amplitude of the final operating pulse voltage will be amplified to 800V. Therefore, the DC voltage output by the DC power supply can be amplified through the energy storage inductor, and the voltage amplification factor can be adjusted according to the driving pulse voltage of the first controllable switch.

[0102] It should be noted that, in the driving mode corresponding to FIG3 , each first controllable switch uses a driving pulse voltage with the same pulse frequency. In order to meet the principle that the conduction periods of the aforementioned first controllable switches do not overlap with each other and the conduction period intervals of two first controllable switches adjacent in the conduction sequence are of a preset duration, there must be a phase difference between the driving pulse voltages of each first controllable switch. As shown in FIG3 , the phase difference between two first controllable switches adjacent in the conduction sequence should be equal to the pulse period of the expected output operating pulse voltage. Accordingly, the preset duration of the conduction period interval of two first controllable switches adjacent in the conduction sequence, that is, the duration of the high level output of the operating pulse voltage. In practical applications, this control can be achieved based on the rising edge of the driving pulse voltage corresponding to the two first controllable switches adjacent in the conduction sequence, or the falling edge of the driving pulse voltage of the first controllable switch that is turned on first and the rising edge of the driving pulse voltage of the first controllable switch that is turned on later can also be used to achieve this control. Of course, other typical moments can also be used. As long as the control method meets the above-mentioned conduction principle, it is optional and also falls within the scope of protection of this application without exceeding the scope of the core idea of ​​this application.

[0103] Based on the above content, taking the pulse frequency of the operating pulse voltage as 10MHz as an example, Figures 4a-4c are schematic diagrams of the simulation control effect of pulse voltage generation using the pulse voltage generating circuit provided in the embodiment of the present application. Among them, Figure 4a is a waveform diagram of the operating pulse voltage finally output by the pulse voltage generating circuit. When the pulse frequency of the operating pulse voltage is 10MHz and the duty cycle is 20%, the pulse width is 20ns, and the voltage amplitude of the operating pulse voltage is 5000V. Due to the flat capacitor effect between the bias electrode and the wafer, when the pulse voltage generating circuit outputs a high level, the wafer surface will also couple out the same high level. At this time, an accelerating electric field will be formed between the high level on the wafer surface and the plasma, attracting electrons to move to the wafer surface, resulting in a decrease in the wafer surface voltage. When the pulse voltage generating circuit outputs a low level, the wafer surface voltage will become a negative voltage, attracting ions to move to the wafer surface. Because ion velocity is much slower than electron velocity, the voltage drop on the wafer surface caused by electrons is much greater than the voltage increase caused by ions. Because the pulse frequency of the operating pulse voltage is sufficiently high, multiple pulse cycles are required to form a stable negative bias pulse waveform on the wafer surface, as shown by the solid line in Figure 4b. In this example, ions are accelerated from the sheath field to the wafer surface during 80% of the pulse cycle, while electrons are accelerated to the wafer surface during the remaining 20% ​​of the pulse cycle to neutralize the residual positive charge on the wafer surface from ion bombardment.

[0104] Generally speaking, the time τ for ions to pass through the sheath field and reach the wafer surface is i for

[0105] in, represents the average thickness of the sheath field;

[0106] m i represents the mass of the ion;

[0107] n0 represents the plasma density;

[0108] represents the mean sheath field voltage.

[0109] Generally, the time it takes for ions to pass through the sheath field and reach the wafer surface is generally several hundred nanoseconds. Since the pulse voltage generating circuit provided in this application can provide a high-frequency operating pulse voltage, ions will pass through the sheath field and reach the wafer surface after going through multiple pulse cycles of the operating pulse voltage. During this process, the ions cannot respond to the sheath field voltage V(t) in real time, but instead feel the average sheath field voltage V d (t), then the following relationship will be satisfied:

[0110] Combined with Figure 4b, the dotted line in the figure shows that when the bias electrode is connected to a high-frequency operating pulse voltage, the average voltage waveform of the sheath field felt by the ions remains basically constant, which will produce a single-peak ion energy distribution as shown in Figure 4c.

[0111] In practical applications, the oscillation range of the average sheath field voltage waveform will determine the broadening of the single-peak IEDF. Generally speaking, the higher the pulse frequency of the operating pulse voltage, the more pulse cycles the ions take to pass through the sheath field to reach the wafer surface, the more obvious the effect of the average sheath field, and the smaller the ion energy broadening caused by the oscillation of the average sheath field voltage waveform. In this case, the average energy E0 of the accelerated ions can be expressed as:

[0112] Wherein, V0 represents the amplitude of the pulse voltage on the wafer surface, which is directly related to the voltage amplitude of the operating pulse voltage output by the pulse voltage generating circuit;

[0113] T on Indicates the pulse width of the operating pulse voltage;

[0114] T represents the pulse period of the operating pulse voltage;

[0115] f represents the pulse frequency of the operating pulse voltage.

[0116] Based on formula (4), it can be seen that the smaller the pulse width of the operating pulse voltage, the greater the average energy of the accelerated ions, and the higher the pulse frequency of the operating pulse voltage, the better the approximate effect of the above formula. This is because the more pulse cycles the ions take to pass through the sheath field and reach the wafer surface, the more obvious the effect of the average sheath field and the more precise the ion energy control.

[0117] Further, referring to Figures 5a and 5b, Figures 5a and 5b are schematic diagrams of the actual control effect of pulse voltage generation by applying the pulse voltage generating circuit provided in the embodiment of the present application, wherein Figure 5a shows the voltage waveform induced on the wafer surface when the operating pulse voltage with a pulse frequency of 10MHz is connected to the bias electrode, and the dotted line in the figure shows the average sheath field voltage waveform actually felt by the ions. Compared with Figure 4a, due to the change in the process chamber load and the inductance of the transmission line, the voltage waveform on the wafer surface will be caused to oscillate, that is, there is a certain range of overshoot (-350V to -300V part) on the falling edge of the operating pulse voltage as shown in Figure 5a. However, since the ions need to go through multiple pulse cycles of the operating pulse voltage before they can cross the sheath field and reach the wafer surface, the average sheath field voltage waveform actually felt by the ions will not be affected, thereby ensuring that the actual single-peak IEDF shown in Figure 5b has a small broadening, which is basically consistent with the simulation effect shown in Figure 4c, meeting the process requirements during actual use.

[0118] Furthermore, referring to the embodiment shown in FIG6 , in the pulse voltage generating circuit provided in this embodiment, the switch unit includes four first controllable switches (ie, S1 - S4 ), and the control timing of the circuit can be seen in FIG7 .

[0119] In t 0- During period t1, the first controllable switch S1 is turned on, and the other three first controllable switches are turned off. At this time, the DC power supply 10 forms a closed loop through the energy storage inductor L1 and the first controllable switch S1. The DC power supply 10 charges the energy storage inductor L1, and the output voltage (i.e., Vout) of the pulse voltage generating circuit is 0V.

[0120] During the period t1 - t2 , the four first controllable switches are all turned off, and the DC power supply 10 and the energy storage inductor L1 simultaneously provide electrical energy to the bias electrode 40 .

[0121] During the period t2-t3, the first controllable switch S2 is turned on and the other three first controllable switches are turned off. At this time, the DC power supply 10 forms a closed loop through the energy storage inductor L1 and the first controllable switch S2. The DC power supply 10 charges the energy storage inductor L1, and the output voltage of the pulse voltage generating circuit drops to 0V again.

[0122] During the period t3 - t4 , the four first controllable switches are all turned off, and the DC power supply 10 and the energy storage inductor L1 simultaneously provide electrical energy to the bias electrode 40 .

[0123] During the period t4-t5, the first controllable switch S3 is turned on and the other three first controllable switches are turned off. At this time, the DC power supply 10 forms a closed loop through the energy storage inductor L1 and the first controllable switch S3. The DC power supply 10 charges the energy storage inductor L1, and the output voltage of the pulse voltage generating circuit drops to 0V again.

[0124] During the period t5 - t6 , the four first controllable switches are all turned off, and the DC power supply 10 and the energy storage inductor L1 simultaneously provide electrical energy to the bias electrode 40 .

[0125] During the period t6-t7, the first controllable switch S4 is turned on and the other three first controllable switches are turned off. At this time, the DC power supply 10 forms a closed loop through the energy storage inductor L1 and the first controllable switch S4. The DC power supply 10 charges the energy storage inductor L1, and the output voltage of the pulse voltage generating circuit drops to 0V again.

[0126] During the period t7-t8, all four first controllable switches are off, and the DC power supply 10 and the energy storage inductor L1 simultaneously supply power to the bias electrode 40. At time t8, the first controllable switch S1 is turned on, and the other three first controllable switches are turned off. This process repeats periodically, ultimately outputting the operating pulse voltage to the bias electrode 40. If the pulse frequency of the driving pulse voltage of the four first controllable switches is 5 MHz, the resulting pulse frequency of the operating pulse voltage is 20 MHz.

[0127] The principle of solving the technical problem and other related control processes of the embodiment shown in FIG6 can be implemented with reference to the aforementioned embodiments and will not be repeated here.

[0128] It should be noted that, when the switch unit includes three or more first controllable switches, the conduction state switching frequency of each first controllable switch can be the same (as shown in the contents shown in Figures 6 and 7) or different (when two first controllable switches are included, the two are alternately turned on, and the conduction state switching frequency must be the same). Taking Figure 6 as an example, when the driving pulse voltage shown in Figure 7 is used, the conduction state switching frequency of each first controllable switch is the same. In another embodiment, the pulse frequency of the driving pulse voltage of the first controllable switch S1 and the first controllable switch S2 can be increased, or the pulse frequency of the driving pulse voltage of the first controllable switch S1 and the first controllable switch S2 can be reduced. Of course, there are other adjustment methods, which are not listed here one by one. In actual applications, different specifications of controllable switches can be matched according to actual needs or circuit design costs. It should be emphasized that no matter how the driving pulse voltage of each first controllable switch is set, the conduction principle of the aforementioned controllable switch must be met. Accordingly, any control method that can meet this principle is optional and also falls within the scope of protection of this application.

[0129] It can be understood that when the conduction state switching frequencies of each first controllable switch are different, the pulse frequency of the operating pulse voltage is still the sum of the pulse frequencies of the driving pulse voltages of each first controllable switch, and the aforementioned voltage amplification factor needs to be calculated in combination with the driving pulse voltages of each first controllable switch, and the sum of the amplification factors corresponding to each first controllable switch is used as the final voltage amplification factor of the switching unit.

[0130] Furthermore, the pulse voltage generating circuit provided in the embodiment shown in FIG6 further includes an oscillation suppression circuit 50. The oscillation suppression circuit 50 is connected between the switch unit 30 and the bias electrode 40 and is configured to output an operating pulse voltage. Specifically, the input end of the oscillation suppression circuit 50 is connected to the connection point between the tank circuit 20 and each first controllable switch, and the output end of the oscillation suppression circuit 50 is connected to the bias electrode 40. The oscillation suppression circuit 50 can suppress voltage fluctuations in the operating pulse voltage output to the bias electrode 40.

[0131] In one possible embodiment, the oscillation suppression circuit 50 includes a diode D2, a second resistor R2 and a third resistor R3, wherein the anode of the diode D2 is connected to the first end of the third resistor R3, and the connection point between the two serves as the input end of the oscillation suppression circuit 50, the cathode of the diode D2 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the second end of the third resistor R3, and the connection point between the two serves as the output end of the oscillation suppression circuit 50, and is connected to the bias electrode 40.

[0132] The pulse voltage generating circuit provided in this embodiment is provided with an oscillation suppression circuit, which can relatively separate the current of the plasma load flowing into the process chamber from the current of the plasma load flowing out of the process chamber through the oscillation suppression circuit, thereby suppressing the pulse voltage waveform oscillation caused by the line inductance between the pulse voltage generating circuit and the bias electrode, making the operating pulse voltage output to the bias electrode more stable, and thus making the wafer induced voltage more stable, thereby effectively improving the pulse voltage generation effect.

[0133] Based on any of the above embodiments, the present application also provides another pulse voltage generating circuit. As shown in Figure 8, the pulse voltage generating circuit provided in this embodiment also includes a parameter acquisition circuit (not shown in Figure 8) and a protection circuit 60.

[0134] In this embodiment, the parameter acquisition circuit is primarily used to collect actual operating pulse voltages at preset sampling points. These preset sampling points include the input and output terminals of the oscillation suppression circuit 50, and at least one of the bias electrodes 40. The functions of each preset sampling point and their connection to the parameter acquisition circuit will be discussed in detail in the subsequent embodiment illustrated in FIG. 9 and will not be described in detail here.

[0135] In this embodiment, the controller is further configured to adjust the output voltage of the DC power supply 10 and / or the conduction state of each first controllable switch based on the actual operating pulse voltage, thereby adjusting the operating pulse voltage ultimately output to the bias electrode 40. The specific adjustment process will be discussed in detail later and will not be described in detail here.

[0136] Furthermore, as shown in FIG8 , the protection circuit 60 is connected between the DC power supply 10 and the energy storage circuit 20. In one possible embodiment, the protection circuit includes a second controllable switch Sp, a third controllable switch Sq, and a first resistor R1. Specifically, the input end of the second controllable switch Sp serves as the first connection end of the protection circuit 60 and is connected to the output end of the DC power supply 10. The output end of the second controllable switch Sp is connected to the input end of the third controllable switch Sq. The connection point between the two serves as the second connection end of the protection circuit 60 and is connected to the input end of the energy storage circuit 20. The output end of the third controllable switch Sq is connected to one end of the first resistor R1, and the other end of the first resistor R1 is grounded. The control ends of the second controllable switch Sp and the third controllable switch Sq are respectively connected to the controller.

[0137] In this embodiment, the controller is further configured to control the protection circuit 60 to disconnect the DC power supply 10 from the energy storage circuit 20 and release the stored energy in the energy storage circuit 20 when the voltage amplitude of the actual operating pulse voltage acquired by the parameter acquisition circuit exceeds a first preset voltage threshold. The specific implementation of the protection process will be discussed in detail later and will not be discussed in detail here.

[0138] To sum up, compared with the above-mentioned embodiments, the pulse voltage generating circuit provided in this embodiment adds a parameter acquisition circuit and a protection circuit. By collecting the actual operating pulse voltage output, overvoltage protection is achieved for the switching unit and the pulse voltage generating circuit as a whole, which helps to improve the safety and service life of each first controllable switch in the switching unit and the pulse voltage generating circuit as a whole.

[0139] Furthermore, the present application also provides a semiconductor process equipment. As shown in FIG9 , the semiconductor process equipment provided by the present application includes a process chamber 140 , a controller 70 , and a pulse voltage generating circuit provided by any of the aforementioned embodiments.

[0140] As previously mentioned, a wafer carrier 130 is disposed within the process chamber 140, and a bias electrode 40 is disposed within the wafer carrier 130. The output end of the pulse voltage generating circuit provided in any of the aforementioned embodiments is connected to the bias electrode 40, outputting an operating pulse voltage to the bias electrode 40. In conjunction with FIG9 , to clearly illustrate the semiconductor process equipment provided in this embodiment, the pulse voltage generating circuit is shown in the form of a structural block diagram. The specific implementation of each sub-circuit of the pulse voltage generating circuit in the embodiment shown in FIG9 can be found in the relevant contents of the aforementioned embodiments and will not be repeated here.

[0141] Furthermore, the semiconductor process equipment provided in this embodiment also includes: a radio frequency power supply 90, an impedance matching circuit 100, an ion current detector 120, and an upper electrode arranged opposite to the wafer carrier 130. As mentioned above, the semiconductor process equipment provided in this application can be an ICP etcher or a CCP etcher. When the semiconductor process equipment is an ICP etcher, the upper electrode is a coupling coil 110. When the semiconductor process equipment is a CCP etcher, the upper electrode is an air intake uniform flow plate. Based on this, in the embodiment shown in Figure 9, the upper electrode is shown as a coupling coil 110.

[0142] Specifically, the RF power supply 90 is mainly used to apply RF power to the upper electrode, thereby generating plasma that bombards the wafer.

[0143] Impedance matching circuit 100 is used for impedance matching of the plasma generation circuit, maximizing the power of RF power source 90 to be applied to coupling coil 110 and process chamber 140. In practical applications, the configuration and matching impedance value of impedance matching circuit 100 need to be determined in conjunction with the actual wiring of process chamber 140, coupling coil 110, and the overall circuit. This application does not limit the specific implementation of impedance matching circuit 100.

[0144] The coupling coil 110 is used to couple the electrical energy output by the RF power supply 90 to the process chamber 140 via electromagnetic field coupling, thereby generating a stable plasma within the process chamber. In practice, to achieve better pulse voltage generation, the coupling coil 110 is typically positioned opposite the bias electrode 40 in the process chamber 140.

[0145] Based on the above content, the output end of the RF power supply 90 is connected to the impedance matching circuit 100, and the impedance matching circuit 100 is connected to the coupling coil 110. After the RF power supply 90 is started, plasma can be generated inside the process chamber 140 through the impedance matching circuit 100 and the coupling coil 110.

[0146] As shown in Figure 9, a wafer carrier 130 is also provided in the process chamber 140, and the wafer 150 to be processed is carried by the wafer carrier 130. In actual applications, the wafer carrier 130 can choose an electrostatic adsorption chuck with an insulating ceramic layer inside. Of course, other implementation methods that can carry the wafer 150 and enable the wafer 150 to generate an induced voltage and thus affect the movement of ions can also be selected, which will not be described in detail here. The bias electrode 40 described in the aforementioned embodiments is arranged inside the wafer carrier 130. After the operating pulse voltage output by the pulse voltage generating circuit is output to the bias electrode 40, the bias electrode 40 and the wafer 150 are between the insulating ceramic layer inside the wafer carrier 130. The bias electrode 40 and the wafer 150 generate a flat capacitor effect. The operating pulse voltage output by the pulse voltage generating circuit will act on the plasma inside the process chamber 140 in a capacitive coupling manner, thereby achieving control of the plasma.

[0147] In a preferred embodiment, the circuit portion of the pulse voltage generating circuit for outputting the operating pulse voltage is arranged directly below the process chamber 140. This effectively shortens the connection line between the pulse voltage generating circuit and the bias electrode 40, thereby greatly reducing the inductance of the connection line, reducing the pulse waveform oscillation caused by the inductance, and helping to improve the control effect of the single-peak IEDF.

[0148] In the aforementioned embodiment, the parameter acquisition circuit 80 is primarily used to acquire the actual operating pulse voltage at preset sampling points. As shown in FIG9 , the preset sampling points are the input of the oscillation suppression circuit 50 (which can also be considered the output of the switch unit 30), the output of the oscillation suppression circuit 50, and the bias electrode 40. It should be noted that in actual applications, one or more of the three preset sampling points may be used. The selection of the preset sampling point depends primarily on factors such as the ease of connecting the parameter acquisition circuit 80 to the preset sampling point, the accuracy of the sampling parameters, and the matching degree between the sampling parameters and the control function. When multiple preset sampling points are used, a controller must be configured to implement a sampling parameter screening mechanism, i.e., how to determine the sampling parameter to be ultimately used from among the multiple sampling parameters.

[0149] In order to enable the parameter acquisition circuit 80 to acquire parameters at multiple preset sampling points, in one possible implementation, the parameter acquisition circuit 80 includes three acquisition modules, namely, an ion energy acquisition module, a first voltage acquisition module, and a second voltage acquisition module.

[0150] The ion energy collection module is connected to the back of the wafer 150 through a conductive pin, and collects the operating pulse voltage induced on the surface of the wafer 150 in real time. It can be understood that the operating pulse voltage can usually be characterized by three parameters, namely voltage amplitude, pulse frequency and pulse width. Based on this, the ion energy collection module includes three main components: voltage amplitude collection module, pulse frequency collection module and pulse width collection module. The voltage amplitude collection module collects the voltage peak value of the operating pulse voltage on the surface of the wafer 150, the pulse frequency collection module collects the pulse frequency of the operating pulse voltage on the surface of the wafer 150, and the pulse width collection module collects the pulse width of the operating pulse voltage on the surface of the wafer 150.

[0151] The first voltage sampling module is used to collect the operating pulse voltage at the input end of the oscillation suppression circuit 50 , and the second voltage sampling module is used to collect the operating pulse voltage at the output end of the oscillation suppression circuit 50 .

[0152] Each component module in the parameter acquisition circuit 80 sends the obtained parameter information to the controller 70, and the controller 70 controls the operation process of the pulse voltage generating circuit. As for the specific control process, it will be expanded in the subsequent content and will not be described in detail here.

[0153] As for the specific implementation methods of other components in the pulse voltage generating circuit shown in Figure 9, such as the DC power supply 10, the protection circuit 60, the energy storage circuit 20, the switching unit 30 and the oscillation suppression circuit 50, please refer to the relevant contents in the aforementioned embodiments and will not be repeated here.

[0154] Furthermore, the pulse voltage generating circuit provided in this embodiment further includes an ion current detector 120 , which can collect ion currents that are accelerated by the sheath field inside the process chamber 140 and bombard the surface of the wafer 150 .

[0155] As shown in FIG10 , the ion current detector 120 includes a filter grid 1201, a first grid electrode 1202, a second grid electrode 1203, and a collector 1204. The filter grid 1201 is designed to allow ions and electrons from the plasma within the process chamber 140 to enter the ion current detector 120. In practical applications, the filter grid 1201 needs to be grounded. The first grid electrode 1202 has the same mesh aperture as the filter grid 1201. During operation, the ion current detector 120 needs to apply a negative voltage of a certain magnitude to the first grid electrode 1202 to prevent electrons from entering the ion collection space within the ion current detector 120. The collector 1204 is used to attract ions into the collection space and thereby detect the ion current. The second grid electrode 1203 has the same mesh aperture as the filter grid 1201, but the negative voltage applied to it is lower than that of the collector 1204, thereby preventing ions from bombarding the collector 1204 and causing secondary electrons to escape, potentially affecting the measurement results. The collecting portion 1204 is made of graphite material and collects the actual ion current bombarding the wafer.

[0156] To feed the ion current collected by the ion current detector 120 back to the controller 70, the parameter acquisition circuit 80 also includes an ion flux acquisition module. This module is connected to the bottom of the collecting portion 1204 of the ion current detector 120 via a wire. This module uses a resistor to convert the actual ion current into a voltage signal and collects the signal. This voltage signal is then used to determine the actual ion flux impacting the wafer 150 and is fed back to the controller 70. The controller 70 then adjusts the output power of the RF power supply 90 based on the actual ion flux, ultimately achieving precise control of the ion flux.

[0157] To sum up, compared with the aforementioned embodiments, the pulse voltage generating circuit provided in this embodiment, on the basis of outputting the operating pulse voltage to realize precise control of the ion energy, also includes a plasma generating circuit and a plasma detector. The output power of the plasma generator is adjusted based on the actual ion flux fed back by the plasma detector and the parameter acquisition circuit, and the ion flux is adjusted, thereby realizing dual control of the ion energy and ion flux, which can effectively improve the pulse voltage generation effect and thus improve the wafer processing technology level.

[0158] In each of the above embodiments, the controller in the semiconductor process equipment mainly realizes the control of the operation process of the semiconductor process equipment. The controller includes at least one memory and at least one processor, and the processor is configured to execute the pulse voltage generation method provided by any embodiment of Figures 11 to 14.

[0159] Referring to FIG11 , an optional embodiment of the pulse voltage generating method provided in the present application includes the following steps:

[0160] S100 , in response to a control instruction, controlling the DC power supply to output a DC voltage, and controlling each first controllable switch in the switch unit to be turned on in sequence, so that the pulse voltage generating circuit outputs an operating pulse voltage for controlling ions.

[0161] In actual applications, the control instruction can come from any device or apparatus that can control the operation of the pulse voltage generating circuit. For example, it can be the semiconductor process equipment to which the pulse voltage generating circuit belongs, or other host computers that can communicate with the controller in the pulse voltage generating circuit. Alternatively, the controller in the pulse voltage generating circuit communicates with other modules in the semiconductor process equipment. When it is determined that the pulse voltage generating circuit needs to operate, the control instruction is automatically generated by the controller itself. This application does not limit the specific method for the pulse voltage generating circuit to obtain the control instruction.

[0162] After receiving the control instruction, the controller controls the DC power supply in the pulse voltage generating circuit to output the DC voltage and controls the switch unit to work, so that the pulse voltage generating circuit outputs the operating pulse voltage.

[0163] In a possible implementation, the control instruction includes a target voltage value. After receiving the control instruction, the controller may control the operation of the DC power supply according to the target voltage value.

[0164] In another possible implementation, the control instruction may only include the enabling information of the DC power supply, and the controller controls the operation of the DC power supply based on the enabling information according to its own preset initial voltage value or the initial voltage value calculated by other parameters.

[0165] In a possible embodiment, the control instruction may also include target parameters for controlling the operation of the switch unit, such as the voltage amplitude, pulse frequency and duty cycle of the driving pulse voltage. After receiving the control instruction, the controller can control the operation of the switch unit according to the target parameters.

[0166] In another possible implementation, the control instruction may also only include the enabling information of the switch unit, and the controller controls the switch unit to operate according to its own preset control information based on the enabling information.

[0167] It should be noted that in the process of controlling the conduction state of each first controllable switch in the switch unit to output the operating pulse voltage, the control rule to be followed is the same: each first controllable switch is turned on sequentially, the conduction periods of each first controllable switch do not overlap, and the conduction periods of two first controllable switches that are adjacent in the conduction sequence are separated by a preset duration. The specific circuit topology of the pulse voltage generating circuit and the specific process of outputting the operating pulse voltage based on this control rule can be referred to the relevant content in the aforementioned embodiment and will not be repeated here.

[0168] With the pulse voltage generation method provided in this embodiment, the pulse frequency of the output operating pulse voltage is the sum of the on-state switching frequencies of each first controllable switch. Therefore, by providing multiple first controllable switches, the pulse frequency of the operating pulse voltage can be effectively increased. For the first controllable switches, when the pulse frequency of the operating pulse voltage is constant, the pulse frequency is shared by each first controllable switch, effectively reducing the on-state switching frequency of each first controllable switch, thereby effectively reducing switching losses. Furthermore, because the energy storage circuit can store electrical energy, when it releases electrical energy within a preset time period, it is superimposed with the electrical energy output by the DC power supply, thereby effectively increasing the voltage amplitude of the operating pulse voltage. Therefore, this application can increase the pulse frequency of the operating pulse voltage while meeting switching loss and voltage amplitude requirements, thereby improving the single-peak IEDF control effect and meeting actual process requirements.

[0169] Moreover, since the pulse frequency of the operating pulse voltage output by the pulse voltage generating circuit is high enough, a good single-peak IEDF control effect can still be achieved without adding other current compensation circuits. Compared with the existing technology, the control logic of the ion circuit control method provided in this embodiment is simpler, which can reduce the logic overhead of the controller and the requirements for the controller hardware performance.

[0170] Further, referring to FIG12 , FIG12 is a flow chart of another pulse voltage generating method provided in an embodiment of the present application. Based on the aforementioned embodiment, the pulse voltage generating method provided in this embodiment includes the following steps.

[0171] S200 , in response to a control instruction, controlling the DC power supply to output a DC voltage, and outputting a driving pulse voltage to each first controllable switch according to a preset driving pulse voltage parameter.

[0172] For the optional implementation of the control instruction and the optional implementation of the controller controlling the DC power supply to output the DC voltage in response to the control instruction, reference may be made to the relevant contents in the aforementioned embodiments and will not be repeated here.

[0173] In the pulse voltage generation method provided in this embodiment, a driving pulse voltage is used to control the conduction state of each first controllable switch in the switch unit. Each first controllable switch uses a driving pulse voltage with the same pulse waveform. Based on this, a controller outputs a driving pulse voltage to each first controllable switch based on preset driving pulse voltage parameters.

[0174] It should be noted that there are multiple parameters that can characterize the driving pulse voltage, such as voltage amplitude, pulse period, pulse frequency, duty cycle and pulse width. The complete driving pulse voltage waveform can be defined by combining some of these parameters. In practical applications, specific driving pulse voltage parameters can be selected according to actual needs.

[0175] It should also be noted that in a certain operating scenario, the waveform of the operating pulse voltage required for processing the wafer can usually be determined in advance. Furthermore, based on the above content, it can be seen that the waveform of the operating pulse voltage is directly affected by the DC voltage output by the DC power supply in the pulse voltage generating circuit, the setting of the first controllable switch in the switching unit, and the driving condition. For a certain pulse voltage generating circuit, the range of the DC voltage output by the DC power supply and the setting of the first controllable switch in the switching unit are both known. Therefore, the initial values ​​of the parameters of the driving pulse voltage and the initial value of the DC voltage of the DC power supply can be reversely determined based on the above information.

[0176] As mentioned above, when using the driving pulse voltage to control the operation of the switch unit, the above-mentioned conduction control rules also need to be met. Therefore, it is necessary to limit the phase difference between the driving pulse voltages corresponding to each first controllable switch. The specific limitation method can be implemented by referring to the relevant content in the above-mentioned embodiment and will not be repeated here.

[0177] S210 , obtaining the actual operating pulse voltage at a preset sampling point in the pulse voltage generating circuit.

[0178] The specific selection of the preset sampling points can refer to the above content and will not be repeated here. The parameter acquisition circuit acquires the actual operation pulse voltage at the preset sampling point and feeds the obtained actual operation pulse voltage back to the controller.

[0179] It should be noted that, similar to the aforementioned driving pulse voltage, the operating pulse voltage can also be characterized by parameters such as voltage amplitude, pulse period, pulse frequency, duty cycle and pulse width. Therefore, obtaining the actual operating pulse voltage mentioned in this step is actually obtaining the actual value of the target parameter among the aforementioned parameters. Of course, the selection of the target parameter is based on the premise of being able to fully describe the operating pulse voltage waveform. For example, the target parameters may include voltage amplitude, pulse frequency and pulse width.

[0180] S220. Determine actual ion energy according to actual operation pulse voltage.

[0181] The specific implementation of calculating the actual ion energy based on the actual operating pulse voltage can be referred to the relevant technology and will not be described in detail here.

[0182] S230 , adjusting the DC voltage output by the DC power supply and / or the conduction process of each first controllable switch so that the energy distribution of the actual ion energy is a single-peak distribution.

[0183] In actual applications, since the working pulse voltage will inevitably produce losses and be affected by electromagnetic interference during the process of transmission to the bias electrode, there will be a certain deviation between the actual working pulse voltage and the working pulse voltage output by the pulse voltage generating circuit, which in turn causes the energy distribution of the actual ion energy used to generate the pulse voltage to be not a single-peak distribution, affecting the ion control effect.

[0184] Based on the above formula (4), the ion energy is affected by the voltage amplitude, pulse width and pulse frequency of the operating pulse voltage. Based on the pulse voltage generating circuit provided in the above embodiment, it can be seen that these parameters are directly affected by the DC voltage output by the DC power supply and the conduction process of each first controllable switch in the switch unit. Therefore, the output operating pulse voltage can be adjusted by adjusting the DC voltage output by the DC power supply and / or the conduction process of each first controllable switch, thereby adjusting the actual ion energy so that the energy distribution of the actual ion energy is a single-peak distribution. Based on the above content, it can be seen that by adjusting each first controllable switch in the switch unit, multiple parameters such as the voltage amplification factor, pulse frequency and pulse width can be changed. Moreover, adjusting the DC voltage and voltage amplification factor of the DC power supply can change the voltage amplitude of the operating pulse voltage.

[0185] It should be noted that since both the DC power supply and the switching unit can affect the final output of the pulse voltage generating circuit, at least one of the DC power supply and the switching unit can be adjusted. Furthermore, in actual adjustment, multiple adjustments are often required to adjust the energy distribution of the actual ion energy to a single peak distribution.

[0186] To sum up, the pulse voltage generating method provided in this embodiment adjusts the operation process of the pulse voltage generating circuit according to the actual ion energy acting on the wafer during the operation of the pulse voltage generating circuit, adjusts the energy distribution of the actual ion energy to a single-peak distribution, effectively improves the control accuracy of the ion energy, and helps to improve the process level of wafer processing.

[0187] Further, referring to FIG13 , FIG13 is a flow chart of another pulse voltage generating method provided in an embodiment of the present application. The pulse voltage generating method provided in this embodiment includes the following steps.

[0188] S300: Obtaining the actual operating pulse voltage at a preset sampling point in the pulse voltage generating circuit.

[0189] In an optional implementation, S300 may be implemented with reference to the relevant content of S210 in the embodiment shown in FIG12 , which will not be repeated here.

[0190] S310: Determine whether the voltage amplitude of the actual operating pulse voltage is greater than a first preset voltage threshold. If so, execute S320.

[0191] In combination with the working process of the pulse voltage generating circuit provided in the above-mentioned embodiment, it can be seen that when all the first controllable switches in the switch unit are turned off, the pulse voltage generating circuit outputs a high level. This high level is obtained by superimposing the electric energy released by the energy storage circuit and the electric energy output by the DC power supply, and has a very high voltage amplitude. Moreover, this high level will be directly applied to each first controllable switch, thereby increasing the risk of the first controllable switch being damaged due to overvoltage.

[0192] To improve the operational safety of each first controllable switch, it is necessary to determine the relationship between the voltage amplitude of the actual operating pulse voltage and the first preset voltage threshold. In practical applications, first controllable switches of different specifications correspond to different maximum withstand voltages. Therefore, the first preset voltage threshold can be set based on the maximum withstand voltage of the first controllable switch. It is understood that the first preset voltage threshold should be less than or equal to the maximum withstand voltage of the first controllable switch. The specific value of the first preset voltage threshold needs to be determined in combination with specific control and protection requirements, and this application does not impose any restrictions on this.

[0193] If the voltage amplitude of the actual operating pulse voltage is greater than the first preset voltage threshold, continue to execute S320. On the contrary, if the voltage amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold, the control pulse voltage generating circuit continues to operate and will not trigger the protection circuit action.

[0194] S320 , controlling the protection circuit to disconnect the DC power supply from the energy storage circuit and release the electric energy stored in the energy storage circuit.

[0195] When the voltage amplitude of the actual operating pulse voltage is greater than the first preset voltage threshold, the control protection circuit disconnects the DC power supply from the energy storage circuit, stops the DC power supply from continuing to provide power to the subsequent circuit, and at the same time, releases the power stored in the energy storage circuit.

[0196] Taking the pulse voltage generating circuit provided in the embodiment shown in Figure 8 as an example, when the voltage amplitude of the actual operating pulse voltage is greater than the first preset voltage threshold, the controller first controls the second controllable switch Sp to turn off, cutting off the output of the DC power supply. At the same time, the controller controls the third controllable switch Sq to turn on, and the electric energy stored in the energy storage inductor L1 will be quickly released through the first resistor R1 to avoid damage to each first controllable switch in the switching unit.

[0197] It can be understood that when the voltage amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold, the controller controls the second controllable switch Sp to turn on, the third controllable switch Sq to turn off, the DC power supply continues to output, and the operating pulse voltage is output after conversion by the switching unit.

[0198] In another possible embodiment, the controller may further set a second preset voltage threshold, wherein the second preset voltage threshold is less than the first preset voltage threshold. When the voltage amplitude of the actual operating pulse voltage is greater than the second preset voltage threshold and less than the first preset voltage threshold, it indicates that the voltage amplitude of the actual operating pulse voltage has reached the warning stage, but has not yet significantly affected the safety of the first controllable switch. The controller may reduce the DC voltage output by the DC power supply to ensure the safety of the first controllable switch when the protection circuit does not operate, that is, when the overall operation of the circuit is not affected. By coordinating the first preset voltage threshold and the second preset voltage threshold, a stepped protection of the first controllable switch and the pulse voltage generating circuit as a whole can be achieved, which can avoid frequent operation of the protection circuit while ensuring the safety of the circuit, thereby improving the stability and reliability of the circuit operation.

[0199] S330: Adjust the DC voltage output by the DC power supply and / or the conduction process of each first controllable switch until the voltage amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold.

[0200] As previously mentioned, the voltage amplitude of the operating pulse voltage output by the pulse voltage generating circuit is primarily affected by two parameters: the DC voltage output by the DC power supply, and the voltage amplification factor of the switching unit. Based on this, after the control protection circuit executes the protection action described in S320, the DC voltage output by the DC power supply can be reduced, or the voltage amplification factor can be reduced by adjusting the conduction process of each first controllable switch. Of course, both of these adjustment measures can be implemented simultaneously until the voltage amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold.

[0201] In practical applications, after one adjustment, the voltage amplitude of the operating pulse voltage can be collected again, and the above steps can be repeatedly performed. After multiple adjustments, the voltage amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold.

[0202] S340, controlling the protection circuit to connect the DC power supply and the energy storage circuit.

[0203] When the amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold, the pulse voltage generating circuit is operating normally. The controller controls the protection circuit to connect the DC power supply and the energy storage circuit. Using the pulse voltage generating circuit shown in FIG8 as an example, the controller controls the third controllable switch Sq to turn off and, accordingly, controls the second controllable switch Sp to turn on, restoring normal circuit operation.

[0204] To sum up, the pulse voltage generating method provided in this embodiment monitors the voltage amplitude of the actual operating pulse voltage, and controls the action and recovery of the protection circuit according to the relationship between the voltage amplitude of the actual operating pulse voltage and the preset voltage threshold, which can effectively improve the safety of each first controllable switch in the switching unit and the overall safety of the pulse voltage generating circuit, thereby improving the stability and reliability of the operation of the pulse voltage generating circuit.

[0205] Furthermore, based on the pulse voltage generating method provided in any of the above embodiments, the following steps as shown in FIG. 14 may also be included.

[0206] S400: Acquire the actual ion flux bombarding the wafer.

[0207] As mentioned above, the pulse voltage generating circuit is provided with an ion current detector and a parameter acquisition circuit. The ion current detector collects the actual ion current inside the process chamber that is accelerated by the sheath field and bombards the wafer surface, and outputs the obtained actual ion current to the parameter acquisition circuit.

[0208] The parameter acquisition circuit includes an ion flux acquisition module, which is connected to the bottom of the ion current detector's collection section via wires. Using resistors, it converts the actual ion current into a voltage signal and collects it, thereby determining the actual ion flux impacting the wafer. A controller is connected to the parameter acquisition circuit to obtain the actual ion flux feedback from the circuit.

[0209] S410 , adjusting the output power of the plasma generator until the deviation between the actual ion flux and the target ion flux is within a preset flux deviation range.

[0210] The target ion flux is the ion flux expected to be required for processing the wafer. It can usually be determined before processing the wafer based on the specifications of the wafer to be processed and the specific processing process. Of course, the target ion flux can also be determined based on other information or methods, which are not limited in this application. In actual application, after the target ion flux is determined, the target ion flux can be stored in the controller.

[0211] Further, taking into account the actual control difficulty and the demand for control accuracy, the present application provides a preset flux deviation range, which limits the deviation between the actual ion flux and the target ion flux by the preset flux deviation range. It can be understood that when the deviation between the actual ion flux and the target ion flux is within the preset flux deviation range, it is believed that the current actual ion flux meets the process requirements. On the contrary, when the deviation between the actual ion flux and the target ion flux is not within the preset flux deviation range, it is believed that the current actual ion flux cannot meet the process requirements. In actual applications, the preset flux deviation range can be set according to the performance of the pulse voltage generating circuit and the specific process requirements. The present application does not limit the specific setting of the preset flux deviation range.

[0212] Based on the above content, when the deviation between the actual ion flux and the target ion flux is not within the preset flux deviation range, the output power of the plasma generator is adjusted until the deviation between the actual ion flux and the target ion flux is within the preset flux deviation range.

[0213] To sum up, compared with the pulse voltage generating method provided in the aforementioned embodiment, the pulse voltage generating method provided in this embodiment, on the basis of outputting the operating pulse voltage to achieve precise control of ion energy, adjusts the output power of the plasma generator based on the actual ion flux feedback from the plasma detector and the parameter acquisition circuit, and adjusts the ion flux, thereby realizing dual control of ion energy and ion flux, which can effectively improve the pulse voltage generation effect and thus improve the wafer processing technology level.

[0214] In some embodiments, this embodiment further provides a computer-readable storage medium, such as a floppy disk, an optical disk, a hard disk, a flash memory, a USB flash drive, an SD (Secure Digital Memory Card), or an MMC (Multimedia Card). The computer-readable storage medium stores one or more instructions for implementing the aforementioned steps. When executed by one or more processors, these one or more instructions cause the processors to perform the pulse voltage generation method described above. For details on the implementation, please refer to the aforementioned description and will not be elaborated upon here.

[0215] In addition to the above-mentioned methods and devices, an embodiment of the present application may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the pulse voltage generation method according to various embodiments of the present application described in the above content of this specification.

[0216] The computer program product may be written in any combination of one or more programming languages ​​to implement the program code for performing the operations of the embodiments of the present application, including object-oriented programming languages ​​such as Java, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0217] Those skilled in the art will appreciate that the contents disclosed in this application may be subject to various modifications and improvements. For example, the various devices or components described above may be implemented through hardware, software, firmware, or a combination of some or all of the three.

[0218] Furthermore, although this application makes various references to certain units in the system according to embodiments of the present application, any number of different units may be used and run on the client and / or server. The units are illustrative only, and different aspects of the system and method may use different units.

[0219] Flowcharts are used in this application to illustrate the steps of the methods according to the embodiments of the present application. It should be understood that the preceding or following steps do not necessarily need to be performed in precise order. Instead, the various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes.

[0220] Those skilled in the art will appreciate that all or part of the steps in the above method can be performed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a read-only memory. Alternatively, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module / unit in the above embodiment can be implemented in the form of hardware or in the form of software functional modules. This application is not limited to any specific form of combination of hardware and software.

[0221] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and should not be interpreted in an idealized or highly formal sense unless expressly defined as such herein.

[0222] The above is an explanation of the present application and should not be considered as limiting thereof. Although several exemplary embodiments of the present application are described, it will be readily understood by those skilled in the art that many modifications may be made to the exemplary embodiments without departing from the novel teachings and advantages of the present application. Therefore, all such modifications are intended to be included within the scope of the present application as defined by the claims. It should be understood that the above is an explanation of the present application and should not be considered as being limited to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims. The present application is defined by the claims and their equivalents.

Claims

1. A pulse voltage generating circuit for semiconductor process equipment, characterized in that: include: A tank circuit and a switch unit, wherein the switch unit includes a plurality of first controllable switches, wherein: The input end of the energy storage circuit is used to be connected to a DC power supply, the output end of the energy storage circuit is respectively connected to the input end of each first controllable switch, and the output end of each first controllable switch is used to be grounded; The connection point between the energy storage circuit and each of the first controllable switches is used to output an operating pulse voltage; The control end of each of the first controllable switches is used to be connected to the controller; Each of the first controllable switches is used to be turned on in sequence under the control of the controller to output the operating pulse voltage; The conduction periods of the first controllable switches do not overlap with each other, and the conduction periods of two first controllable switches that are adjacent in conduction sequence are separated by a preset time interval; The energy storage circuit is used to store electrical energy when any of the first controllable switches is turned on, and release the electrical energy within the preset time period.

2. The pulse voltage generating circuit according to claim 1, wherein: The controller is configured as follows: According to preset driving pulse voltage parameters, a driving pulse voltage is output to each of the first controllable switches respectively, wherein the driving pulse voltage is used to control the conduction state of the first controllable switch.

3. The pulse voltage generating circuit according to claim 1, wherein: Also includes: Oscillation suppression circuit, where The input end of the oscillation suppression circuit is connected to the energy storage circuit and the connection point of each of the first controllable switches, and the output end of the oscillation suppression circuit is used to output the operating pulse voltage; The oscillation suppression circuit is used to suppress voltage fluctuations of the operating pulse voltage.

4. The pulse voltage generating circuit according to claim 3, wherein: Also includes: Parameter acquisition circuit, where The parameter acquisition circuit is used to collect the actual operating pulse voltage at a preset sampling point, wherein the preset sampling point includes at least one of the input end of the oscillation suppression circuit, the output end of the oscillation suppression circuit, and a bias electrode, and the bias electrode is located in the wafer carrier of the semiconductor process equipment; The controller is configured to adjust the DC voltage output by the DC power supply and / or the conduction process of each of the first controllable switches according to the actual operating pulse voltage.

5. The pulse voltage generating circuit according to claim 4, wherein: Also includes: protection circuit, where The first connection end of the protection circuit is used to be connected to the output end of the DC power supply, and the second connection end of the protection circuit is connected to the input end of the energy storage circuit; The controller is connected to the control end of the protection circuit; The controller is configured to control the protection circuit to disconnect the DC power supply from the energy storage circuit and release the electric energy stored in the energy storage circuit when the voltage amplitude of the actual operating pulse voltage is greater than a first preset voltage threshold.

6. The pulse voltage generating circuit according to claim 5, characterized in that: The protection circuit includes: a second controllable switch, a third controllable switch and a first resistor, wherein: The input terminal of the second controllable switch serves as the first connection terminal of the protection circuit; A connection point between the output terminal of the second controllable switch and the input terminal of the third controllable switch serves as a second connection terminal of the protection circuit; The output end of the third controllable switch is connected to one end of the first resistor, and the other end of the first resistor is grounded; The control ends of the second controllable switch and the third controllable switch are respectively connected to the controller.

7. The pulse voltage generating circuit according to any one of claims 1 to 6, characterized in that: The energy storage circuit includes: an energy storage inductor and a voltage stabilizing capacitor, wherein: The first end of the energy storage inductor is connected to the first end of the voltage stabilizing capacitor, and the second end of the energy storage inductor serves as the output end of the energy storage circuit; The second end of the voltage stabilizing capacitor is used for grounding; The connection point between the energy storage inductor and the voltage stabilizing capacitor serves as the input end of the energy storage circuit.

8. A semiconductor process equipment, characterized in that: include: A process chamber, a controller, and a pulse voltage generating circuit according to any one of claims 1 to 7, wherein: A wafer carrying device is provided in the process chamber, and a bias electrode is provided in the wafer carrying device; The controller is electrically connected to the control end of each first controllable switch of the pulse voltage generating circuit; The output end of the pulse voltage generating circuit is connected to the bias electrode; The controller is used to control the pulse voltage generating circuit to output an operating pulse voltage to the bias electrode to control ion energy distribution.

9. The semiconductor process equipment according to claim 8, wherein: Also includes: Radio frequency coil, matching device and radio frequency power supply, wherein, The RF power supply is used to apply RF power to the RF coil through the matching device to excite plasma in the process chamber; The controller is also electrically connected to the RF power supply to control the output power of the RF power supply.

10. The semiconductor process equipment according to claim 9, wherein: Also includes: Ion current detector, where The ion current detector is used to collect the actual ion current bombarding the wafer placed on the wafer carrier, and the actual ion current is used to characterize the actual ion flux; The controller is further configured to adjust the radio frequency power of the radio frequency power supply until a deviation between the actual ion flux and the target ion flux is within a preset flux deviation range.

11. The semiconductor process equipment according to any one of claims 8 to 10, characterized in that: The controller is further configured to perform the following steps: Obtaining an actual operating pulse voltage at a preset sampling point in the pulse voltage generating circuit; determining actual ion energy according to the actual operating pulse voltage; The DC voltage output by the DC power supply connected to the pulse voltage generating circuit and / or the conduction process of each first controllable switch in the pulse voltage generating circuit are adjusted so that the energy distribution of the actual ion energy is a single-peak distribution.

12. The semiconductor process equipment according to claim 11, wherein: The pulse voltage generating circuit includes a protection circuit and an energy storage circuit, and the controller is further configured to perform the following steps: If the voltage amplitude of the actual operating pulse voltage is greater than a first preset voltage threshold, controlling the protection circuit to disconnect the DC power supply from the energy storage circuit and release the electric energy stored in the energy storage circuit; Adjusting the DC voltage output by the DC power supply and / or the conduction process of each of the first controllable switches until the voltage amplitude of the actual operating pulse voltage is less than or equal to the first preset voltage threshold; The protection circuit is controlled to connect the DC power supply and the energy storage circuit.

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