Ion energy control system and control method

Abstract

This invention provides an ion energy control system and a control method. The ion energy control system is used to output a voltage of a preset waveform to a bias electrode. The ion energy control system includes: a waveform generation circuit that generates a voltage of the preset waveform; and an oscillation suppression circuit, wherein the output terminal of the waveform generation circuit is electrically connected to a first terminal of the oscillation suppression circuit, and the second terminal of the oscillation suppression circuit is electrically connected to a load circuit. The oscillation suppression circuit is used to suppress current oscillations in the load circuit when the voltage generated by the waveform generation circuit changes abruptly. By setting an oscillation suppression circuit between the waveform generation circuit and the load circuit, the ion energy control system of this invention can suppress current oscillations in the load circuit when the voltage generated by the waveform generation circuit changes abruptly, thereby reducing the impact on the bias waveform and improving control accuracy.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more specifically, to an ion energy control system and control method. Background Technology

[0002] Etching is a crucial step in semiconductor manufacturing. It removes surface material to create circuit elements on a chip. Plasma is typically used in etching to etch the material. Plasma is formed by applying a high voltage to a gas containing a large number of ions and free electrons. When the plasma comes into contact with the material being processed, the ions strike the surface and etch it.

[0003] To achieve high-precision etching, ion energy needs to be controlled. This is typically achieved using a bias waveform. The bias waveform is the voltage waveform applied during etching, which controls plasma formation and ion energy. The shape of the bias waveform is crucial for controlling the etching process. Therefore, precise control over the shape and amplitude of the bias waveform is necessary.

[0004] In practical applications, parasitic inductance and capacitance in a circuit can form a resonant circuit when voltage changes abruptly. Within this resonant circuit, energy continuously transfers between the parasitic capacitance and inductance, causing voltage and current oscillations. These oscillations distort the bias waveform and make controlling ion energy extremely difficult, thus affecting the control of the bias waveform. Summary of the Invention

[0005] The present invention aims to solve the problem in the prior art that when the voltage changes suddenly, the parasitic inductance and parasitic capacitance in the circuit will form a resonant circuit, which will affect the control of the bias waveform.

[0006] According to a first aspect of the present invention, an ion energy control system is disclosed for outputting a voltage of a preset waveform to a bias electrode. The ion energy control system includes: a waveform generation circuit that generates a voltage of the preset waveform; and an oscillation suppression circuit, wherein the output terminal of the waveform generation circuit is electrically connected to a first terminal of the oscillation suppression circuit, and a second terminal of the oscillation suppression circuit is electrically connected to a load circuit. The oscillation suppression circuit is used to suppress current oscillation in the load circuit when the voltage generated by the waveform generation circuit undergoes a sudden change.

[0007] Further, the oscillation suppression circuit includes: a unidirectional branch, the first end of which is electrically connected to the waveform generation circuit and the first end of which is used to be electrically connected to the load circuit; the unidirectional branch is conductive in the direction from the output terminal of the waveform generation circuit to the load circuit and is disconnected in the direction from the load circuit to the output terminal of the waveform generation circuit; and an oscillation suppression resistor connected in parallel with the unidirectional branch, the oscillation suppression resistor being used to dissipate the energy of the oscillating current in the load circuit when the voltage change generated by the waveform generation circuit occurs.

[0008] Furthermore, the unidirectional branch includes: a first unidirectional switch and a first resistor, the first unidirectional switch and the first resistor are connected in series, the conduction direction of the first unidirectional switch is from the output terminal of the waveform generation circuit to the load circuit, and the first resistor is smaller than the oscillation suppression resistor.

[0009] Furthermore, there are multiple first one-way switches, which are connected in series.

[0010] Furthermore, the oscillation suppression circuit further includes an adjustable resistor, which is connected in parallel with the oscillation suppression resistor.

[0011] Furthermore, the oscillation suppression circuit further includes: a resistance adjustment branch, which is connected in parallel with the oscillation suppression resistor, and the resistance adjustment branch has a third resistor and a branch switch connected in series, the branch switch being used to control the on / off state of the resistance adjustment branch.

[0012] Furthermore, there are multiple resistance adjustment branches, each of which is connected in parallel with the oscillation suppression circuit. The multiple resistance adjustment branches adjust the energy consumption rate of the oscillation current by controlling the number of branch switches that are opened and closed.

[0013] Further, the waveform generation circuit includes: a power supply branch, a first end of which is grounded, and a second end of which is the output terminal of the waveform generation circuit. The power supply branch has a first DC source and a first switch connected in series, with the first switch located between the first DC source and the second end of the power supply branch; a constant current source branch, a first end of which is grounded; a second switch, a first end of which is electrically connected to the first end of the power supply branch, and a second end of which is electrically connected to the second end of the constant current source branch; and a third switch, a first end of which is electrically connected to the second end of the power supply branch, and a second end of which is electrically connected to the second end of the constant current source branch.

[0014] Furthermore, the waveform generation circuit also includes a controller, which is electrically connected to the first switch, the second switch and the third switch respectively. The controller is used to control the first switch, the second switch and the third switch to open and close sequentially in a preset order so that the waveform generation circuit outputs a voltage of a preset waveform.

[0015] Furthermore, the constant current source branch includes: a second DC source, the first end of which is a ground terminal; a first inductor, the first end of which is electrically connected to the second end of the second DC source, and the second end of which is electrically connected to the second end of the second switch and the second end of the third switch, respectively.

[0016] Further, the constant current source branch includes: a second DC source, the first end of which is a ground terminal; a first switch, the first end of which is electrically connected to the second end of the second DC source, and the second end of which is electrically connected to the second end of the second switch and the second end of the third switch; and a control unit, which is electrically connected to the first switch and is used to adjust the on-resistance of the first switch to adjust the current flowing through the first switch.

[0017] According to a second aspect of the present invention, a control method for an ion energy control system is also disclosed. The control method is used to control the aforementioned ion energy control system. The control method includes: a first time period: controlling the first switch to be off, the second switch to be on, and the third switch to be on; a second time period: controlling the first switch to be off, the second switch to be on, and the third switch to be off; a third time period: controlling the first switch to be on, the second switch to be on, and the third switch to be off; a fourth time period: controlling the first switch to be off, the second switch to be on, and the third switch to be off; a fifth time period: controlling the first switch to be off, the second switch to be on, and the third switch to be on; and a sixth time period: controlling the first switch to be off, the second switch to be off, and the third switch to be on.

[0018] The ion energy control system of the present invention provides an oscillation suppression circuit between the waveform generation circuit and the load circuit. When the voltage change generated by the waveform generation circuit occurs, the oscillation suppression circuit can suppress the current oscillation in the load circuit, reduce the impact on the bias waveform, and thus improve the control accuracy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the ion energy control system according to Embodiment 1 of the present invention;

[0020] Figure 2 This is a circuit diagram of the ion energy control system according to Embodiment 1 of the present invention;

[0021] Figure 3 This is a current flow diagram of the ion energy control system in Embodiment 1 of the present invention during the t2-t3 stage;

[0022] Figure 4 This is a current flow diagram of the ion energy control system in Embodiment 1 of the present invention during the t4-t6 stage;

[0023] Figure 5 This is a circuit diagram of the oscillation suppression circuit of the ion energy control system in Embodiment 2 of the present invention;

[0024] Figure 6 This is a circuit diagram of the oscillation suppression circuit of the ion energy control system in Embodiment 3 of the present invention;

[0025] Figure 7 This is a current flow diagram of the oscillation suppression circuit of the ion energy control system in Embodiment 3 of the present invention during the t2-t3 stage;

[0026] Figure 8 This is a current flow diagram of the oscillation suppression circuit of the ion energy control system in Embodiment 3 of the present invention during the t4-t6 stage;

[0027] Figure 9 This is a current flow diagram of the waveform generation circuit of the ion energy control system in Embodiment 1 of the present invention during the t0-t1 stage.

[0028] Figure 10 This is a current flow diagram of the waveform generation circuit of the ion energy control system in Embodiment 1 of the present invention during the t1-t2 stage.

[0029] Figure 11 This is a current flow diagram of the waveform generation circuit of the ion energy control system in Embodiment 1 of the present invention during the t2-t3 stage.

[0030] Figure 12 This is a current flow diagram of the waveform generation circuit of the ion energy control system in Embodiment 1 of the present invention during the t3-t4 stage.

[0031] Figure 13 This is a current flow diagram of the waveform generation circuit of the ion energy control system in Embodiment 1 of the present invention during the t4-t5 stage.

[0032] Figure 14 This is a current flow diagram of the waveform generation circuit of the ion energy control system in Embodiment 1 of the present invention during the t5-t6 stage.

[0033] Figure 15 This is a switching timing control diagram of the waveform generation circuit of the ion energy control system according to Embodiment 1 of the present invention;

[0034] Figure 16 The waveform diagram shows the sheath voltage in the prior art;

[0035] Figure 17 The waveform of the sheath voltage generated by the ion energy control system of Embodiment 1 of the present invention is shown.

[0036] Figure 18 This is a schematic diagram of the waveform generation circuit of the ion energy control system according to Embodiment 4 of the present invention;

[0037] List of reference numerals in the attached diagram:

[0038] 10. Waveform generation circuit; 11. Power supply branch; 111. First DC source; 112. First switch; 12. Constant current source branch; 121. Second DC source; 122. First inductor; 123. First switching transistor; 124. Control unit; 13. Second switch; 14. Third switch; 15. Controller; 16. First protection element; 17. Second protection element; 18. Third protection element; 20. Oscillation suppression circuit; 21. Unidirectional branch; 211. First unidirectional switch; 212. First resistor; 22. Oscillation suppression resistor; 23. Adjustable resistor; 24. Resistor adjustment branch; 241. Third resistor; 242. Branch switch; 243. Second unidirectional switch; 30. Bias electrode; 40. Load circuit. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the ion energy control system and control method provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0040] Existing technology uses a stepped voltage gradient method, employing four DC sources and five electronic switches to control the alternating power supply of each DC source. By controlling the timing, the electronic switches are turned on and off in a specific sequence, generating a customized bias waveform. Because the voltage changes gradually in a stepped manner through the four DC sources, sudden voltage changes are avoided, and the interference of parasitic capacitance and inductance on the bias waveform is weakened.

[0041] However, the use of four DC power supplies and five electronic switches increases the complexity of the circuitry and switch control timing. This also results in a larger overall size and increased equipment cost. Furthermore, the ion energy control system of this invention not only reduces waveform oscillations but also simplifies the circuit structure.

[0042] like Figure 1As shown, the present invention discloses an ion energy control system for outputting a voltage with a preset waveform to a bias electrode 30. The ion energy control system includes a waveform generation circuit 10 and an oscillation suppression circuit 20. The waveform generation circuit 10 generates a voltage with a preset waveform. The output terminal of the waveform generation circuit 10 is electrically connected to the first terminal of the oscillation suppression circuit 20, and the second terminal of the oscillation suppression circuit 20 is electrically connected to a load circuit 40. The oscillation suppression circuit 20 is used to suppress current oscillation in the load circuit 40 when the voltage generated by the waveform generation circuit 10 changes abruptly.

[0043] The ion energy control system of the present invention provides an oscillation suppression circuit 20 between the waveform generation circuit 10 and the load circuit 40. When a voltage change occurs generated by the waveform generation circuit 10, the oscillation suppression circuit 20 can suppress the current oscillation in the load circuit 40, reduce the impact on the bias waveform, and thus improve the control accuracy.

[0044] The following is combined with Figure 1 and Figure 2 The first embodiment of the present invention will be used to specifically describe the ion energy control system of the present invention.

[0045] like Figure 1 and Figure 2 As shown, in this embodiment, the waveform generation circuit 10 includes: a power supply branch 11, a constant current source branch 12, a second switch 13, a third switch 14, and a controller 15.

[0046] The first end of the power supply branch 11 is used for grounding, and the second end of the power supply branch 11 is the output end of the waveform generation circuit 10. The power supply branch 11 has a first DC source 111 and a first switch 112 connected in series. The first switch 112 is located between the first DC source 111 and the second end of the power supply branch 11. The first end of the constant current source branch 12 is used for grounding. The first end of the second switch 13 is electrically connected to the first end of the power supply branch 11, and the second end of the second switch 13 is electrically connected to the second end of the constant current source branch 12. The first end of the third switch 14 is electrically connected to the second end of the power supply branch 11, and the second end of the third switch 14 is electrically connected to the second end of the constant current source branch 12.

[0047] The controller 15 is electrically connected to the first switch 112, the second switch 13 and the third switch 14 respectively. The controller 15 is used to control the first switch 112, the second switch 13 and the third switch 14 to open and close in sequence according to a preset order, so that the waveform generation circuit 10 outputs a voltage with a preset waveform.

[0048] It should be noted that in this embodiment, the first switch 112, the second switch 13 and the third switch 14 can be switching transistors, and the control terminal of each switching transistor is electrically connected to the controller 15, so that the controller 15 can control the opening and closing of the first switch 112, the second switch 13 and the third switch 14 respectively.

[0049] It should also be noted that the waveform generation circuit 10 further includes a first protection element 16, a second protection element 17, and a third protection element 18. The first protection element 16 is connected in parallel with the first switch 112, and its first end is electrically connected to the first DC source 111, while its second end is electrically connected to the second end of the power supply branch 11. The second protection element 17 is connected in parallel with the second switch 13, and its first end is electrically connected to the first end of the power supply branch 11, while its second end is electrically connected to the second end of the constant current source branch 12. The third protection element 18 is connected in parallel with the third switch 14, and its first end is electrically connected to the second end of the power supply branch 11, while its second end is electrically connected to the second end of the constant current source branch 12.

[0050] In this embodiment, the first protection element 16, the second protection element 17, and the third protection element 18 are all diodes. By connecting diodes in parallel, the safety of the switching transistor can be ensured, and the high voltage pulse generated by reverse voltage and inductance can be prevented from damaging the switching transistor, thus effectively protecting the normal operation of the switching transistor.

[0051] The oscillation suppression circuit 20 includes a unidirectional branch 21 and an oscillation suppression resistor 22. The first end of the unidirectional branch 21 is electrically connected to the waveform generation circuit 10 and is also electrically connected to the load circuit 40. The unidirectional branch 21 is open from the output of the waveform generation circuit 10 to the load circuit 40 and closed from the output of the waveform generation circuit 10 to the load circuit 40. The oscillation suppression resistor 22 is connected in parallel with the unidirectional branch 21 and is used to dissipate the energy of the oscillating current in the load circuit 40 when the voltage change generated by the waveform generation circuit 10 occurs. The unidirectional branch 21 includes a first unidirectional switch 211 and a first resistor 212, which are connected in series. The first unidirectional switch 211 is open from the output of the waveform generation circuit 10 to the load circuit 40, and the first resistor 212 is smaller than the oscillation suppression resistor 22.

[0052] During use, such as Figure 3 As shown, when the current flows from the waveform generation circuit 10 to the load circuit 40, that is, when the current flows from... Figure 3When the current flows from the left side to the right side, it will pass through the unidirectional branch 21 and the oscillation suppression resistor 22 respectively. Since the first resistor 212 is smaller than the oscillation suppression resistor 22, most of the current will flow through the unidirectional branch 21, avoiding current loss in the oscillation suppression resistor 22.

[0053] like Figure 4 As shown, when the voltage change generated by the waveform generation circuit 10 suddenly occurs, an oscillating current is generated in the load circuit 40. During the oscillation process, the current flows from the load circuit 40 to the waveform generation circuit 10, that is, the oscillating current flows from... Figure 4 The flow moves from the right side to the left. At this time, due to the action of the first one-way switch 211, the one-way branch 21 is... Figure 4 The circuit is open from right to left, so the oscillating current can only pass through the oscillation suppression resistor 22. Because the resistance of the oscillation suppression resistor 22 is relatively large, it can effectively dissipate the energy of the oscillating current, causing the oscillating current to decay rapidly, thus suppressing current oscillation. Furthermore, when the first switch 112 is a switching transistor, the first resistor 212 can limit the magnitude of the transient current on the first switch 112 at the instant the first switch 112 is turned on, protecting the first switch 112.

[0054] It should be noted that in the above embodiment one, the oscillation suppression circuit 20 includes a unidirectional branch 21 and an oscillation suppression resistor 22, but this is not limiting. For example... Figure 5 The illustrated embodiment two is essentially the same as embodiment one, except that in this embodiment, the oscillation suppression circuit 20 further includes an adjustable resistor 23, which is connected in parallel with the oscillation suppression resistor 22. The resistor can be adjusted to a suitable value based on waveform testing to reduce the voltage and current oscillations in the current loop of the ion energy control system and the equivalent model of the chamber load.

[0055] like Figures 6 to 8 The third embodiment also discloses an ion energy control system, which is basically the same as the first embodiment, except that in this embodiment, the oscillation suppression circuit 20 further includes a resistance adjustment branch 24, which is connected in parallel with the oscillation suppression resistor 22. The resistance adjustment branch 24 has a third resistor 241, a second one-way switch 243, and a branch switch 242 connected in series. The branch switch 242 is used to control the on / off state of the resistance adjustment branch 24. The conduction direction of the second one-way switch 243 is from the load circuit 40 to the waveform generation circuit 10. By setting the second one-way switch 243, the current flowing from the waveform generation circuit 10 to the load circuit 40 can be prevented from being lost in the third resistor 241. There are multiple resistance adjustment branches 24, and all of the multiple resistance adjustment branches 24 are connected in parallel with the oscillation suppression circuit 20. The multiple resistance adjustment branches 24 adjust the energy rate of consuming the oscillation current by controlling the number of branch switches 242 that are opened and closed.

[0056] During use, such as Figure 7 As shown, when the current flows from the waveform generation circuit 10 to the load circuit 40, that is, when the current flows from... Figure 7 When the current flows from the left side to the right side, the branch switch 242 is opened, and the current will pass through the unidirectional branch 21 and the oscillation suppression resistor 22 respectively. Since the first resistor 212 is smaller than the oscillation suppression resistor 22, most of the current will flow through the unidirectional branch 21, avoiding current loss in the oscillation suppression resistor 22.

[0057] like Figure 8 As shown, when the voltage change generated by the waveform generation circuit 10 suddenly occurs, an oscillating current is generated in the load circuit 40. During the oscillation process, the current flows from the load circuit 40 to the waveform generation circuit 10, that is, the oscillating current flows from... Figure 8 The flow shifts from the right side to the left. At this time, branch switch 242 closes, and due to the action of the first one-way switch 211, one-way branch 21... Figure 8 The circuit is open from right to left, and the oscillating current can only pass through the oscillation suppression resistor 22 and the resistor adjustment branch 24. Because the resistance values ​​of the oscillation suppression resistor 22 and the third resistor 241 are relatively large, they can effectively dissipate the energy of the oscillating current, causing it to decay rapidly and thus suppressing current oscillation. Furthermore, by setting multiple resistor adjustment branches 24, the number of closed branch switches 242 can be adjusted according to the waveform test results, thereby adjusting the resistance to a suitable value and reducing the voltage and current oscillations in the current loop of the ion energy control system and the equivalent model of the chamber load.

[0058] It should also be noted that in this embodiment, the first unidirectional switch 211 is a diode, and there are two first unidirectional switches 211 on the unidirectional branch 21, which are connected in series. Multiple first unidirectional switches 211 connected in series can reduce the equivalent junction capacitance of the diode when using a single diode, and prevent the high-frequency current of oscillation from flowing through the unidirectional branch 21.

[0059] In existing technologies, since the oscillating current generated during voltage surges cannot be suppressed, four DC sources are used to gradually change the voltage in a stepped manner to reduce the impact of the oscillating current on the bias waveform control. This method, using four DC sources, not only results in a larger overall device size but also increases costs due to the complex circuit design and switching control timing. While this stepped voltage change method reduces oscillations, it also means the generation of multiple low-potential voltages, increasing the pulse width and the number of ions with low-energy peaks. Furthermore, the increased number of switching transistors leads to larger voltage division across them, consequently increasing losses.

[0060] Because this invention incorporates an oscillation suppression circuit 20, it can suppress the influence of oscillating current on the bias waveform control when a voltage change occurs. Therefore, the number of DC sources can be significantly reduced; for example, in this embodiment, only two DC sources and three switching transistors are used, resulting in fewer components and a simpler structure. Furthermore, the voltage can be directly boosted to a preset voltage, reducing the voltage transition phase and effectively improving the quality of the ion energy control bias waveform. Due to the reduced voltage transition phase, the waveform period is shorter, which can reduce the proportion of low-energy peak ions.

[0061] The following is combined with Figures 9 to 15 The control method of the ion energy control system of Embodiment 1 of the present invention will be described in detail.

[0062] In such Figures 9 to 14 In the first embodiment, the constant current source branch 12 includes: a second DC source 121 and a first inductor 122. The first end of the second DC source 121 is a ground end; the first end of the first inductor 122 is electrically connected to the second end of the second DC source 121, and the second end of the first inductor 122 is electrically connected to the second end of the second switch 13 and the second end of the third switch 14, respectively.

[0063] like Figure 15 As shown, each cycle of the bias waveform is divided into six stages from t0 to t6. The control method includes the following steps:

[0064] First time period: Control the first switch 112 to open, the second switch 13 to open, and the third switch 14 to open. For example... Figure 9 As shown, during the t0-t1 stage, the first switch 112 is open, the second switch 13 is closed, and the third switch 14 is closed. During this stage, the first inductor 122 stores energy, the current in the first inductor 122 gradually increases, and the output potential of the waveform generation circuit 10 rises to ground potential.

[0065] Second time period: Control the first switch 112 to open, the second switch 13 to open, and the third switch 14 to open. For example... Figure 10 As shown, during the t1-t2 stage, the first switch 112 is open, the second switch 13 is closed, and the third switch 14 is open. During this stage, the current in the first inductor 122 continues to increase.

[0066] The third time period: Control the first switch 112 to be on, the second switch 13 to be on, and the third switch 14 to be off. For example... Figure 11 As shown, during the t2-t3 stage, the first switch 112 is turned on, the second switch 13 is turned on, and the third switch 14 is turned off. During this stage, the first inductor 122 continues to store energy, and the output potential of the waveform generation circuit 10 rises to the voltage of the first DC source 111.

[0067] Fourth time period: Control the first switch 112 to open, the second switch 13 to open, and the third switch 14 to open. For example... Figure 12 As shown, during the t3-t4 stage, the first switch 112 is open, the second switch 13 is closed, and the third switch 14 is closed. During this stage, the first inductor 122 continues to store energy.

[0068] Fifth time period: Control the first switch 112 to open, the second switch 13 to open, and the third switch 14 to open. For example... Figure 13 As shown, during the t4-t5 stage, the first switch 112 is open, the second switch 13 is closed, and the third switch 14 is closed. During this stage, the first inductor 122 continues to store energy, and the output potential of the waveform generation circuit 10 drops to ground potential.

[0069] Sixth time period: Control the first switch 112 to open, the second switch 13 to open, and the third switch 14 to open. For example... Figure 14 As shown, during the t5-t6 stage, the first switch 112 is open, the second switch 13 is open, and the third switch 14 is closed. The current in the first inductor 122 cannot change abruptly and continues to flow. The first inductor 122 draws charge from the plasma load, and simultaneously, the voltage waveform at the output of the waveform generation circuit 10 is formed as shown in the figure. Figure 15 During the Tslope phase, after the voltage across the first inductor 122 reverses, the current in the first inductor 122 gradually decreases.

[0070] It should be noted that the slope of the Tslope stage can be adjusted to a suitable steepness by adjusting the voltage of the second DC source 121. Figure 15 The Uchuck waveform is similar to a negative bias waveform, where Uchuck is... Figure 1 Waveform of the upper surface voltage of the wafer inside the cavity.

[0071] It should also be noted that, such as Figure 3 As shown, during the t2-t3 stage, the current flows from the waveform generation circuit 10 to the load circuit 40, that is, the current flows from... Figure 3 When the current flows from the left side to the right side, it will pass through the unidirectional branch 21 and the oscillation suppression resistor 22 respectively. Since the first resistor 212 is smaller than the oscillation suppression resistor 22, most of the current will flow through the unidirectional branch 21, avoiding current loss in the oscillation suppression resistor 22.

[0072] like Figure 4 As shown, during the t4-t6 stage, the voltage generated by the waveform generation circuit 10 undergoes a sudden change, resulting in an oscillating current in the load circuit 40. During the oscillation process, the current flows from the load circuit 40 to the waveform generation circuit 10, i.e., the oscillating current originates from... Figure 4 The flow moves from the right side to the left. At this time, due to the action of the first one-way switch 211, the one-way branch 21 is... Figure 4The circuit is open from right to left. Therefore, the oscillating current can only pass through the oscillation suppression resistor 22. Since the resistance value of the oscillation suppression resistor 22 is relatively large, it can effectively consume the energy of the oscillating current, thereby causing the oscillating current to decay rapidly and thus achieving the effect of suppressing current oscillation.

[0073] like Figure 16 The waveform shown is the sheath voltage without the oscillation suppression circuit 20 of the present invention. Because the current on the parasitic inductance of the circuit cannot change abruptly, the circuit current continuously charges and discharges the parasitic capacitance, resulting in strong voltage oscillations in both the Tpulse and Tslope phases.

[0074] like Figure 17 As shown, when the oscillation suppression circuit 20 of the present invention is used, the oscillation suppression circuit 20 can absorb the energy of the oscillation, and there is almost no oscillating sheath voltage waveform.

[0075] This invention uses three voltage stages (t0-t2, t2-t4, t4-t6) to generate ion energy-controlled bias. Compared with existing technologies, the Tpulse stage reduces the dwell time of two voltage stages, allowing for a shorter Tpulse stage duration. This results in a relatively smaller number of low-energy ions being accelerated during this time period, leading to a lower proportion of low-energy peak ions. Furthermore, the reduced number of DC power supplies, switching transistors, and diodes lowers costs and simplifies circuit design and switching control timing.

[0076] It should be noted that in the above embodiment one, the constant current source branch 12 includes a second DC source 121 and a first inductor 122, but this is not limiting. Figure 18 In Embodiment 4, which is basically the same as Embodiment 1, the difference is that the constant current source branch 12 includes: a second DC source 121, a first switch 123, and a control unit 124. The first terminal of the second DC source 121 is grounded. The first terminal of the first switch 123 is electrically connected to the second terminal of the second DC source 121, and the second terminal of the first switch 123 is electrically connected to the second terminals of the second switch 13 and the third switch 14, respectively. The control unit 124 is electrically connected to the first switch 123 and is used to adjust the on-resistance of the first switch 123 to regulate the current flowing through the first switch 123. By utilizing the dynamic resistance characteristics of the first switch 123 to construct a constant current source, when the voltage of the second DC source 121 is constant and appropriate, adjusting the voltage of the DC source in the control unit 124 changes the output level of the comparator, changes the control voltage of the first switch 123, changes the on-resistance of the first switch 123, and thus regulates the current flowing through the first switch 123. This implementation method provides higher accuracy in compensating for current control.

[0077] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An ion energy control system for outputting a voltage of a preset waveform to a bias electrode (30), characterized in that, The ion energy control system includes: A waveform generation circuit (10) generates a voltage of a preset waveform; The oscillation suppression circuit (20) is provided, wherein the output terminal of the waveform generation circuit (10) is electrically connected to the first terminal of the oscillation suppression circuit (20), and the second terminal of the oscillation suppression circuit (20) is used to be electrically connected to the load circuit (40). The oscillation suppression circuit (20) is used to suppress the current oscillation in the load circuit (40) when the voltage change generated by the waveform generation circuit (10) occurs. The oscillation suppression circuit (20) includes: A unidirectional branch (21) is provided, the first end of which is electrically connected to the waveform generation circuit (10). The first end of the unidirectional branch (21) is used to be electrically connected to the load circuit (40). The unidirectional branch (21) is connected in the direction from the output end of the waveform generation circuit (10) to the load circuit (40), and disconnected in the direction from the load circuit (40) to the output end of the waveform generation circuit (10). An oscillation suppression resistor (22) is connected in parallel with the unidirectional branch (21). The oscillation suppression resistor (22) is used to consume the energy of the oscillating current in the load circuit (40) when the voltage change generated by the waveform generation circuit (10) occurs.

2. The ion energy control system according to claim 1, characterized in that, The unidirectional branch (21) includes: a first unidirectional switch (211) and a first resistor (212), the first unidirectional switch (211) and the first resistor (212) are connected in series, the conduction direction of the first unidirectional switch (211) is from the output terminal of the waveform generation circuit (10) to the load circuit (40), and the first resistor (212) is smaller than the oscillation suppression resistor (22).

3. The ion energy control system according to claim 2, characterized in that, There are multiple first one-way switches (211), and multiple first one-way switches (211) are connected in series.

4. The ion energy control system according to claim 1, characterized in that, The oscillation suppression circuit (20) further includes: An adjustable resistor (23) is connected in parallel with the oscillation suppression resistor (22).

5. The ion energy control system according to claim 1, characterized in that, The oscillation suppression circuit (20) further includes: A resistance adjustment branch (24) is connected in parallel with the oscillation suppression resistor (22). The resistance adjustment branch (24) has a third resistor (241) and a branch switch (242) connected in series. The branch switch (242) is used to control the on / off state of the resistance adjustment branch (24).

6. The ion energy control system according to claim 5, characterized in that, There are multiple resistance adjustment branches (24), and each of the multiple resistance adjustment branches (24) is connected in parallel with the oscillation suppression circuit (20). The multiple resistance adjustment branches (24) adjust the energy rate of consuming the oscillation current by controlling the number of branch switches (242) that are opened and closed.

7. The ion energy control system according to any one of claims 1 to 6, characterized in that, The waveform generation circuit (10) includes: A power supply branch (11) has a first end for grounding and a second end for output of the waveform generation circuit (10). The power supply branch (11) has a first DC source (111) and a first switch (112) connected in series. The first switch (112) is located between the first DC source (111) and the second end of the power supply branch (11). A constant current source branch (12), the first end of which is used for grounding; The second switch (13) has its first end electrically connected to the first end of the power supply branch (11) and its second end electrically connected to the second end of the constant current source branch (12). The third switch (14) has its first end electrically connected to the second end of the power supply branch (11), and its second end electrically connected to the second end of the constant current source branch (12).

8. The ion energy control system according to claim 7, characterized in that, The waveform generation circuit (10) further includes: The controller (15) is electrically connected to the first switch (112), the second switch (13) and the third switch (14) respectively. The controller (15) is used to control the first switch (112), the second switch (13) and the third switch (14) to open and close in sequence according to a preset order so that the waveform generation circuit (10) outputs a voltage of a preset waveform.

9. The ion energy control system according to claim 7, characterized in that, The constant current source branch (12) includes: The second DC source (121) has a ground terminal at its first end. The first inductor (122) has its first end electrically connected to the second end of the second DC source (121), and its second end is electrically connected to the second end of the second switch (13) and the second end of the third switch (14).

10. The ion energy control system according to claim 7, characterized in that, The constant current source branch (12) includes: The second DC source (121) has a ground terminal at its first end. The first switch (123) has its first end electrically connected to the second end of the second DC source (121), and its second end is electrically connected to the second end of the second switch (13) and the second end of the third switch (14). Control unit (124) is electrically connected to the first switch (123). The control unit (124) is used to adjust the on-resistance of the first switch (123) to adjust the current flowing through the first switch (123).

11. A control method for an ion energy control system, characterized in that, The control method is used to control the ion energy control system according to any one of claims 7 to 10; the control method includes: First time period: control the first switch (112) to be open, the second switch (13) to be open, and the third switch (14) to be open; Second time period: control the first switch (112) to be open, the second switch (13) to be open, and the third switch (14) to be open; Third time period: control the first switch (112) to be turned on, the second switch (13) to be turned on, and the third switch (14) to be turned off; Fourth time period: control the first switch (112) to be open, the second switch (13) to be open, and the third switch (14) to be open; Fifth time period: control the first switch (112) to be open, the second switch (13) to be open, and the third switch (14) to be open; Sixth time period: control the first switch (112) to open, the second switch (13) to open, and the third switch (14) to open.

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