Semiconductor processing equipment and DC voltage signal control system thereof

Abstract

The present invention provides semiconductor processing equipment and a DC voltage signal control system therefor. In this system, a first signal generation module and a second signal generation module are controlled to operate independently and in mutually exclusive states, obtaining DC power to generate a first DC voltage signal and a second DC voltage signal that do not overlap in the time domain. These signals are then provided to the semiconductor processing equipment to form a bias voltage to control the acceleration of charged particles in the plasma. This invention can simplify the system structure, achieve fast-response switch control, prevent circuit short circuits, improve the safety and stability of system operation, enhance the flexibility of signal control, perform targeted optimization of pulse waveforms, and improve the process performance of semiconductor processing.

Description

Technical Field

[0001] The present invention relates to semiconductor manufacturing technology, and in particular to a semiconductor processing device and a direct current voltage signal control system thereof. Background Art

[0002] As market demand for advanced storage devices continues to grow, the requirements for semiconductor manufacturing processes are becoming increasingly stringent, and the impact of voltage on the processing process is particularly important. In traditional semiconductor processing equipment, a high-frequency radio frequency signal excites the neutral gas in the reaction chamber to generate plasma, which serves as a source of charged particles. A second low-frequency radio frequency signal then creates a strong negative bias voltage, accelerating the positively charged particles in the reaction chamber, causing them to rapidly bombard the surface of the substrate being processed to form the desired micro-nanostructures.

[0003] Taking high-aspect-ratio etching processes as an example, micro-nanostructures with etch depths significantly greater than the etch width need to be formed on the substrate. To ensure that the structural features meet the desired requirements, high process performance requirements, such as etching accuracy and speed, are imposed. Traditional RF bias schemes, however, have limitations in the development and application of these high-aspect-ratio etching processes. For example, because RF signals have alternating positive and negative amplitudes and their intensity exhibits periodic variations over time, the voltage remains at its peak for a very short time. This results in the generated bias voltage being unable to maintain a stable maximum acceleration capability during charged particle acceleration, leading to particle path deviation and poor processing accuracy. Furthermore, RF signal modulation is complex, and the design and optimization of the RF source and matching network are limited by factors such as component performance and control strategies, making rapid voltage adjustment difficult. Bias voltage changes are synchronized with the RF signal waveform, and the frequency and periodic fluctuations of the RF signal limit the speed and flexibility of bias adjustment. Furthermore, charged particles in the plasma require time to respond to changes in the electric field, resulting in a lag in the actual effect of bias adjustment. This makes it impossible to meet the bias control rate and voltage slew rate requirements of high-aspect-ratio processes, impacting etching efficiency and quality. Summary of the Invention

[0004] The purpose of the present invention is to provide a semiconductor processing device and a DC voltage signal control system thereof, which uses a high-voltage DC pulse signal instead of a low-frequency radio frequency signal to generate a bias voltage, can simplify the system design, realize fast-response switch control, enhance the flexibility of signal regulation, and can maintain a stable voltage level within a controllable time period, thereby improving the continuity of the movement of charged particles in the plasma in the same direction and enhancing the process performance of semiconductor processing.

[0005] A technical solution of the present invention is to provide a DC voltage signal control system, comprising:

[0006] A power module is used to provide DC power;

[0007] The first signal generating module, when in an on state, is used to obtain DC power and generate a first DC voltage signal;

[0008] The second signal generating module, when in an on state, is used to obtain DC power and generate a second DC voltage signal;

[0009] The master control module is coupled to the first signal generating module and the second signal generating module respectively; the control signal provided by the master control module includes an instruction for making the enabling states of the first signal generating module and the second signal generating module mutually exclusive, so that the generated first DC voltage signal and the second DC voltage signal do not overlap in the time domain.

[0010] Optionally, the DC voltage signal control system further includes:

[0011] a DC energy supply module, the input end of which is coupled to the power supply module, and the output end of which is coupled to the first signal generating module and the second signal generating module respectively;

[0012] The DC energy supply module stores the DC power obtained from the power supply module, and outputs the stored DC power to the first signal generation module or the second signal generation module in the turned-on state.

[0013] Optionally, the DC voltage signal control system further includes:

[0014] A sensing module, used to monitor the working conditions of the first signal generating module and the second signal generating module;

[0015] The analysis and processing module is coupled with the sensor module and the master control module respectively, and is used to obtain the monitored parameters from the sensor module for analysis and processing, and feed back the analysis and processing results to the master control module, which sets the control signal.

[0016] Optionally, each unit of the signal waveform of the first DC voltage signal includes a continuous first signal transition segment, a first signal maintaining segment, and a first signal returning segment:

[0017] The voltage value in the first signal transition section is adjusted from the first reference value to within the threshold range of the first set value; the voltage value in the first signal holding section is within the threshold range of the first set value; and the voltage value in the first signal return section is adjusted from the threshold range of the first set value to the first reference value;

[0018] Each unit of the signal waveform of the second DC voltage signal includes a continuous second signal transition segment, a second signal maintaining segment, and a second signal returning segment:

[0019] The voltage value in the second signal transition segment is adjusted from the second reference value to the threshold range of the second set value; the voltage value in the second signal maintaining segment is within the threshold range of the second set value; the voltage value in the second signal return segment is adjusted from the threshold range of the second set value to the second reference value.

[0020] Optionally, the control signal provided by the master control module includes corresponding instructions for causing the first DC voltage signal and / or the second DC voltage signal to satisfy any one of the following or any combination thereof:

[0021] The first DC voltage signal and the second DC voltage signal have the same or opposite voltage polarity;

[0022] The first DC voltage signal and the second DC voltage signal have the same or different frequencies;

[0023] The first DC voltage signal and the second DC voltage signal have the same or different duty cycles;

[0024] The first reference value is the same as or different from the second reference value;

[0025] The first set value and the second set value have the same or different absolute magnitudes;

[0026] The upper threshold value of the first set value and the upper threshold value of the second set value have the same or different absolute values;

[0027] The lower threshold limit of the first set value and the lower threshold limit of the second set value have the same or different absolute values;

[0028] The first signal maintaining segment and the second signal maintaining segment have the same or different durations;

[0029] The first signal transition segment and the second signal transition segment have the same or different durations;

[0030] The first signal return segment and the second signal return segment have the same or different durations;

[0031] The signal waveforms of adjacent units in the first DC voltage signal are the same or different;

[0032] The signal waveforms of adjacent units in the second DC voltage signal are the same or different.

[0033] Optionally, the control signal provided by the master control module includes: instructions for making the on state and the off state periodically switched by the first signal generating module mutually exclusive with the on state and the off state periodically switched by the second signal generating module, so that the first DC voltage signal and the second DC voltage signal are alternately generated to form a DC pulse signal, and the first DC voltage signal is the first pulse component of the DC pulse signal, and the second DC voltage signal is the second pulse component of the DC pulse signal.

[0034] Optionally, in the unit pulse waveform of the DC pulse signal, the duty cycle of the first signal maintaining segment and the duty cycle of the second signal maintaining segment are both within a set value range.

[0035] Optionally, the first signal generating module outputs the DC voltage corresponding to the first signal maintaining segment to the load terminal, or outputs the DC voltage corresponding to the first signal transition segment, the first signal maintaining segment, and the first signal returning segment to the load terminal;

[0036] The second signal generating module outputs the DC voltage corresponding to the second signal maintaining section to the load terminal, or outputs the DC voltage corresponding to the second signal transition section, the second signal maintaining section, and the second signal returning section to the load terminal.

[0037] Optionally, the load terminal receiving the first DC voltage signal and the second DC voltage signal includes a semiconductor processing device; the first signal maintaining segment of the first DC voltage signal and the second signal maintaining segment of the second DC voltage signal provide the required bias voltage for the semiconductor processing device.

[0038] Optionally, links for transmitting energy and / or information are respectively provided between the modules of the DC voltage signal control system, and between the DC voltage signal control system and the load terminal receiving the first DC voltage signal and the second DC voltage signal; the links include transmission paths based on at least one form of electricity, mechanics, and optics.

[0039] Another technical solution of the present invention is to provide a semiconductor processing device, comprising a vacuum reaction chamber, in which a base is provided for supporting a substrate; a process gas introduced into the reaction chamber is excited by radio frequency energy coupled into the reaction chamber to form a plasma for processing the substrate; any one of the above-mentioned DC voltage signal control systems provides a first DC voltage signal and a second DC voltage signal that do not overlap in the time domain as bias voltages to a bias electrode in the base.

[0040] Optionally, the semiconductor processing equipment is used to perform a high aspect ratio etching process.

[0041] Compared with the prior art, the semiconductor processing equipment and DC voltage signal control system provided by the present invention have at least the following beneficial effects:

[0042] Unlike the traditional method of forming a bias voltage through a low-frequency RF signal, the embodiment of the present invention uses a high-voltage DC signal for high-frequency pulse modulation, which can maintain the voltage of the DC pulse signal near the voltage peak within an adjustable time period. The bias voltage thus formed can provide a relatively stable electric field environment in the reaction chamber of the semiconductor processing equipment, improve the continuity of the movement of charged particles in the plasma in the same direction, and enable the charged particles to obtain stable and continuous maximum acceleration capability.

[0043] In this embodiment of the present invention, the two signal generation modules operate independently, rapidly responding to control signals to execute their respective switching actions, achieving higher switching frequencies and voltage slew rates. The exemplary DC voltage signal control system can stably and accurately generate DC pulse voltages with periods in the microsecond or nanosecond range, meeting the switching frequency and voltage slew rate requirements of processes such as high-aspect-ratio etching, while improving etching speed and accuracy.

[0044] In an embodiment of the present invention, the on states of the two signal generating modules are mutually exclusive, and the DC pulse signal generates pulse components that do not overlap in the time domain. The voltage effects of each pulse component can be clearly distinguished, and the control effect on the charged particle acceleration process can be produced. Therefore, the parameters of different pulse components can be optimized in a targeted manner to accurately output a DC pulse signal whose pulse waveform, time characteristics, etc. meet the requirements of semiconductor process.

[0045] In order to avoid the voltage signals in different potential switching stages from overlapping in the time domain and possibly interfering with each other, or even causing a short circuit fault in the circuit in severe cases, which may lead to sparking and damage to the components in the system or the reaction chamber, in the embodiment of the present invention, by setting the control strategy and related algorithms, and monitoring the key parameters in the signal generation process in real time through the sensor module, it is ensured that the on states of the two signal generation modules are mutually exclusive, and the generated DC voltage signals will not overlap in the time domain, thereby avoiding the occurrence of short circuit faults and improving the safety and stability of the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of a semiconductor processing device according to an embodiment of the present invention.

[0047] Figure 2 It is a schematic diagram of the structure of the DC voltage signal control system according to an embodiment of the present invention.

[0048] Figure 3 yes Figure 2 Schematic diagram of the composition structure of the medium and high voltage electrical signal controller.

[0049] Figure 4 Schematic diagram of the DC pulse signal waveform according to an embodiment of the present invention.

[0050] Figure 5 It is a schematic diagram of the device configuration of the DC voltage signal control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0052] like Figure 1 As shown, the semiconductor processing equipment of this embodiment includes a vacuum-evacuable reaction chamber 10, which is provided with a generally cylindrical metal cavity. The cavity sidewall is provided with an opening (not shown) for a robot to carry a substrate w in and out of the reaction chamber 10. A pedestal 20 with an electrostatic chuck is provided within the reaction chamber 10 to support the substrate w. An RF source 30 provides source RF power (e.g., in the frequency range of 100 kHz to 200 MHz) that is coupled into the reaction chamber 10, exciting the process gas injected into the chamber to form a plasma. The plasma contains a large number of active species, such as electrons, ions, excited atoms, molecules, and free radicals. These active species can undergo various physical and chemical reactions with the surface of the substrate w, changing the surface morphology of the substrate w and completing processes such as etching the substrate w. An exhaust pump 50, connected to the reaction chamber 10, discharges residual gases and reaction byproducts from the reaction chamber 10 to maintain the vacuum environment within the chamber.

[0053] The semiconductor processing equipment is, for example, a capacitively coupled plasma reaction device, an inductively coupled plasma reaction device, an electron cyclotron resonance plasma reaction device, a remote plasma reaction device, a plasma edge etching device, but is not limited thereto. Figure 1 Taking the capacitively coupled plasma reaction device shown as an example, a gas shower head 60 for introducing process gas into the reaction chamber 10 serves as an upper electrode and is arranged opposite to the base 20 serving as a lower electrode. An RF source 30 is connected to the upper electrode and / or the lower electrode to apply source RF power, thereby generating an RF electric field between the upper electrode and the lower electrode to dissociate the process gas in the chamber into plasma.

[0054] The DC voltage signal control system 40 of this embodiment can generate a high-voltage DC pulse signal and provide it to a load terminal; the load terminal is a semiconductor processing device, specifically a voltage-coupled reactor containing a base 20. The bias electrode within the base 20 receives the DC pulse signal, forming a bias voltage within the reaction chamber 10 to control the acceleration process of charged particles in the plasma when bombarding the substrate w. Compared with the previous scheme of generating bias voltage by low-frequency radio frequency signals, the DC pulse signal used in the present invention can maintain the voltage near a preset voltage peak within a controllable time period. The resulting bias voltage forms a relatively stable electric field environment within the reaction chamber 10, allowing the charged particles to obtain continuous maximum acceleration under the action of this electric field and maintaining a consistent acceleration path for the charged particles, effectively improving the accuracy and efficiency of plasma processing of the substrate w.

[0055] like Figure 2 、 Figure 3 As shown, the DC voltage signal control system is provided with a high-voltage electric signal controller 102, which is coupled to the power module 101 and the load terminal 103 respectively through the corresponding link 104; the power module 101 is used to provide DC power; the high-voltage electric signal controller 102 can obtain DC power, generate a DC pulse signal suitable for semiconductor process through a preset control strategy and provide it to the load terminal 103. In which, the high-voltage electrical signal controller 102 further includes a main control module 201, and a first signal generating module 202 and a second signal generating module 203 respectively coupled to the main control module 201 and controlled by it; when the first signal generating module 202 is in the on state, it can obtain DC power and generate a first DC voltage signal; when the second signal generating module 203 is in the on state, it can obtain DC power and generate a second DC voltage signal; the control signal output by the main control module 201 includes corresponding instructions for making the on states of the first signal generating module 202 and the second signal generating module 203 mutually exclusive, so that the first DC voltage signal and the second DC voltage signal generated by the two modules 202 and 203 will not overlap in the time domain.

[0056] Furthermore, the instructions contained in the control signal are also used to periodically switch the on state and off state of the first signal generating module 202, periodically switch the on state and off state of the second signal generating module 203, and make the switching state of the first signal generating module 202 and the switching state of the second signal generating module 203 mutually exclusive (that is, the on states of the first signal generating module 202 and the second signal generating module 203 are mutually exclusive, and the off states of the first signal generating module 202 and the second signal generating module 203 are also mutually exclusive), so that the first DC voltage signal and the second DC voltage signal can be generated alternately, and then the first DC voltage signal and the second DC voltage signal are synthesized into a DC pulse signal to be output to the load terminal 103, wherein the first DC voltage signal and the second DC voltage signal are respectively used as the first pulse component and the second pulse component of the DC pulse signal.

[0057] When the master control module 201 sets the control signal according to the control strategy, the waveform, amplitude, width and frequency of the first DC voltage signal and the second DC voltage signal can be configured separately, and the first signal generating module 202 and the second signal generating module 203 can be driven to make corresponding adjustments, so as to achieve flexible and precise control of the voltage state of the DC pulse signal under different pulse components, so as to optimize the pulse waveform, time characteristics, etc. of the final output DC pulse signal according to the semiconductor process requirements; wherein, the opening states of the first signal generating module 202 and the second signal generating module 203 are mutually exclusive, so that the first DC voltage signal and the second DC voltage signal do not overlap in the time domain, which can reduce the circuit complexity, prevent the two signals from interfering with each other, and avoid the high-voltage power supply switch (such as the first signal generating module) and the grounding switch (such as the second signal generating module) from being turned on during the signal generation process. The first and second signal generating modules 202 and 203 are directly connected to each other to prevent a short-circuit fault in the circuit, thereby making the output DC pulse signal more stable and improving the safety and reliability of the system operation; when two DC voltage signals that do not overlap in the time domain are output to the load terminal 103, the different bias control effects of the two signals on the charged particle acceleration process can be more clearly distinguished, facilitating the subsequent feedback adjustment of the parameters of the first and second DC voltage signals; the first signal generating module 202 and the second signal generating module 203 work independently and only need to undertake the signal processing tasks related to their respective pulse components, so that they can quickly respond to the control signal issued by the master control module 201 to execute the switching action required to generate the DC voltage signal, effectively reducing the switching delay, so that the output DC pulse signal can quickly switch between the voltage states corresponding to different pulse components, and improve the dynamic response performance of the entire system.

[0058] For example, when semiconductor processing equipment is used in a high aspect ratio etching process, it is necessary to form a micro-nano structure on the substrate w with an etching depth much greater than the etching width; the DC voltage signal control system equipped for the semiconductor processing equipment can stably and accurately generate a DC pulse signal with a high amplitude (such as a voltage of several thousand or even tens of thousands of volts) and a short period (a period in the microsecond or nanosecond level), so that the DC pulse signal can quickly switch between the high pulse position and the low pulse position, meeting the high switching rate and high voltage swing rate requirements of the high aspect ratio etching process for bias control, so as to achieve instant control and rapid adjustment of the ion beam energy and directionality during the etching process, improve the etching rate and accuracy, make the contour, size, morphology and other features of the micro-nano structure meet the expected design, and realize high-quality microelectronic device manufacturing.

[0059] The following is a schematic description of the first DC voltage signal, the second DC voltage signal, and the DC pulse signal formed by the cooperation of the first DC voltage signal and the second DC voltage signal.

[0060] The signal waveform of the first DC voltage signal in each pulse cycle includes a first signal transition segment in which the voltage value is adjusted from the first reference value to the threshold range of the first set value; a first signal maintenance segment in which the voltage value is within the threshold range of the first set value; and a first signal return segment in which the voltage value is adjusted from the threshold range of the first set value to the first reference value. The signal waveform of the second DC voltage signal in each pulse cycle includes a second signal transition segment in which the voltage value is adjusted from the second reference value to the threshold range of the second set value; a second signal maintenance segment in which the voltage value is within the threshold range of the second set value; and a second signal return segment in which the voltage value is adjusted from the threshold range of the second set value to the second reference value. The first signal transition segment, the first signal maintenance segment, the first signal return segment, the second signal transition segment, the second signal maintenance segment, and the second signal return segment of the first DC voltage signal are continuously formed in the following order to obtain a unit pulse waveform of the DC pulse signal.

[0061] Under the control strategy of the master control module 201 and the corresponding control signals, the parameters of the first DC voltage signal and the second DC voltage signal that can be independently adjusted include but are not limited to the waveform and frequency of each DC voltage signal, the voltage polarity and absolute amplitude of each reference value, the voltage polarity and absolute amplitude of each set value, the upper and lower limits of each threshold range, the duration and duty cycle of each signal maintenance segment, the duration of each signal transition segment, the duration of each signal return segment, and the like.

[0062] In different examples, for the same unit pulse waveform, the first DC voltage signal and the second DC voltage signal can have the same or different configurations for the same parameter items; in adjacent unit pulse waveforms, the first DC voltage signal can have the same or different configurations for the same parameter items, so that the waveforms of the first DC voltage signal in adjacent units are the same or different; in adjacent unit pulse waveforms, the second DC voltage signal can have the same or different configurations for the same parameter items, so that the waveforms of the second DC voltage signal in adjacent units are the same or different. This can obtain a DC pulse signal with a signal waveform, time characteristics, and other characteristics that meet the set requirements, forming the bias voltage required by the semiconductor process. For example, by adjusting the frequency and amplitude of the DC pulse signal, the ion energy and its distribution in the plasma can be controlled, thereby affecting the etching depth, rate and uniformity. The direction of the electric field can be controlled by the voltage polarity, thereby affecting the acceleration or deceleration of the charged particles. The duration of the signal transition segment or the return segment can reflect the switching speed of the corresponding signal generating device, and respectively reflect the speed at which the charged particles switch from acceleration start to continuous acceleration, and from continuous acceleration to acceleration deceleration. The duration of the signal transition segment and the return segment will affect processing effects such as etching uniformity, surface damage, and contour accuracy. The signal maintenance segment corresponds to the continuous acceleration stage. Its duration and duty cycle control the acceleration time of the charged particles, which will affect the etching depth, selectivity and etching rate.

[0063] like Figure 4As shown, in one embodiment of the DC pulse signal waveform, the first reference value and the second reference value have the same reference potential 307; the first DC voltage signal is a high-order pulse component whose voltage value is higher than the reference potential 307 as a whole, and the second DC voltage signal is a low-order pulse component whose voltage value is lower than the reference potential 307 as a whole. In a unit pulse waveform, the first signal generating module 202 is first turned on (the second signal generating module 203 is turned off at this time), and the generated first DC voltage signal corresponds to the first half cycle (t1~t3) of the unit pulse waveform. The voltage starts to rise from the reference potential 307 and reaches the first set value 308 after the rising time t1, forming a first signal transition segment 301; the voltage remains above the first set value 308 for a period of time t2, forming a first signal maintaining segment 302; the voltage then starts to decrease from the first set value 308 and returns to the reference potential 307 after the falling time t3, forming a first signal return segment 303; then, the first signal generating module 202 is turned off, and the same At this time, the second signal generating module 203 is turned on, and the generated second DC voltage signal corresponds to the second half cycle of the unit pulse waveform (t4~t6), causing the voltage to continue to drop from the reference potential 307, and reach the second set value 309 after the drop time t4, forming a second signal transition section 304; the voltage remains below the second set value 309 for a maintenance time t5, forming a second signal maintenance section 305; the voltage starts to rise from the second set value 309 again, and returns to the reference potential 307 after the rise time t6, forming a second signal return section 306; at this point, the second signal generating module 203 is turned off, and the first signal generating module 202 is turned on at the same time, entering the next cycle of the unit pulse waveform.

[0064] In this example, the voltage value being within the threshold range of the first set value 308 means that the absolute amplitude of the voltage in the first signal maintenance segment 302 is between the first set value 308 and the voltage of the DC power (e.g., the voltage value in the first signal maintenance segment 302 may fluctuate slightly within this threshold range, or may remain unchanged at a high pulse value at or above the first set value 308). The voltage value being within the threshold range of the second set value 309 means that the absolute amplitude of the voltage in the second signal maintenance segment 305 is between the second set value 309 and the voltage of the DC power (the voltage value in the second signal maintenance segment 305 may fluctuate slightly within this threshold range, or may remain unchanged at a low pulse value at or below the second set value 309). The high pulse value and the low pulse value may have the same voltage polarity; alternatively, one of the pulse values ​​may be 0; or alternatively, the high pulse value and the low pulse value may have opposite voltage polarities (and the first set value 308 and the second set value 309 may have the same or different absolute amplitudes). It should be noted that the above is only an example. For example, the upper and lower limits of each threshold range, the numerical relationship between each signal maintenance segment voltage and the threshold range, the setting of high / low pulse values, etc. can all be adjusted according to actual needs, and the present invention does not impose any restrictions on this.

[0065] The duration of each of the above-mentioned signal transition segments, maintenance segments, and return segments can be independently configured and adjusted. For example, in the same unit pulse waveform or adjacent unit pulse waveforms, the slopes of the first signal transition segment 301 and the first signal return segment 303 can be symmetrical or asymmetrical, and the durations of the rise time t1 and the fall time t3 can be the same or different; the slopes of the second signal transition segment 304 and the second signal return segment 306 can be symmetrical or asymmetrical, and the durations of the rise time t4 and the fall time t6 can be the same or different; the durations of the rise times t1 and t6 of the two DC voltage signals can be the same or different, and the durations of the fall times t3 and t4 of the two DC voltage signals can be the same or different; the total duration of the first half cycle of the first DC voltage signal (t1+t2+t3) and the total duration of the second half cycle of the second DC voltage signal (t4+t5+t6) can be the same or different. By adjusting the duration, set values, and threshold ranges of each signal transition, hold, and return segment, the waveform and time characteristics of the first and second DC voltage signals can be controlled. For example, if the voltage values ​​within the first and second signal hold segments are maintained at high and low pulse values, respectively, the resulting DC pulse signal waveform approximates a trapezoidal or rectangular wave (a trapezoidal wave has its own set slope for each signal transition and return segment, while a rectangular wave has extremely short signal transition and return segments).

[0066] As can be seen, compared to the signal transition segments 301 and 304 or the signal return segments 303 and 306, where the voltage values ​​fluctuate significantly, the voltage values ​​of the DC pulse signal corresponding to the first signal maintaining segment 302 and the second signal maintaining segment 305 can be maintained at relatively stable potential levels. Therefore, when the voltages of the first signal maintaining segment 302 and the second signal maintaining segment 305 act on the load terminal 103 to form a bias, the electric field strength and direction are relatively stable, and the charged particles in the plasma can obtain a desired energy gain, thereby accurately and efficiently controlling the acceleration process of the charged particles. Therefore, in the output DC pulse signal, the duty cycle of the first signal maintaining segment 302 and the second signal maintaining segment 305 in the unit pulse waveform is within a set value range (for example, the first signal maintaining segment 302 and the second signal maintaining segment 305 each have a duty cycle of 1% or greater). The resulting bias can improve the continuity of the charged particles' movement in the same direction and enhance the acceleration efficiency. This stable and controllable acceleration process plays an important role in high aspect ratio etching processes. It can improve the ratio of etching depth to width, reduce sidewall roughness and morphology deviation, and obtain a more uniform etching effect.

[0067] For example, in the first half of the cycle, the continuous first signal transition segment 301, the first signal maintaining segment 302, and the first signal return segment 303 of the first DC voltage signal can be completely output to the load terminal 103, or although the various segments of the first DC voltage signal are continuously generated, the first signal generating module 202 is controlled to output only the first signal maintaining segment 302 to the load terminal 103; in the second half of the cycle, the continuous second signal transition segment 304, the second signal maintaining segment 305, and the second signal return segment 306 of the second DC voltage signal can be completely output to the load terminal 103, or although the various segments of the second DC voltage signal are continuously generated, the second signal generating module 203 is controlled to output only the second signal maintaining segment 305 to the load terminal 103, so as to mainly utilize the voltages of the first signal maintaining segment 302 and the second signal maintaining segment 305 to form a bias and provide a relatively stable electric field environment to control the acceleration process of the charged particles.

[0068] The following describes an example structure of the DC voltage signal control system. Figure 2 、 Figure 3 、 Figure 5As shown, the master control module 201 of the high-voltage electrical signal controller 102 is constructed with a control chip as the core, and is used to set the control strategy and provide corresponding control signals to control the operation of other modules in the system. The power supply module 101 is used to provide the DC power required to generate the DC pulse signal, and can also power other modules in the system that need it; the power supply module 101 may include, for example, a power adapter that can convert external AC power into the DC power required by the system, or a DC converter that can convert other DC voltage levels into the DC voltage level required by the system.

[0069] In some examples, the first signal generation module 202 and the second signal generation module 203 can be directly coupled to the power module 101 to obtain the DC power provided by the power module 101. In other examples, the system is provided with a DC energy supply module 206 to assist the power module 101 in providing stable DC power and cooperate with the first signal generation module 202 and the second signal generation module 203 to form the waveform generation module 401. The DC energy supply module 206 includes an energy storage device (such as a capacitor or a battery), and its input end is coupled to the power module 101 via the corresponding link 104 to obtain the DC power provided by the power module 101 for storage. The output end of the DC energy supply module 206 is coupled to the first signal generation module 202 and the second signal generation module 203, respectively, to provide the stored DC power to the first signal generation module 202 or the second signal generation module 203 when it is in the on state. The exemplary DC energy supply module 206 may be provided with a set of energy storage devices; or, it may be provided with multiple sets of energy storage devices at the same time, for example, for storing positive voltage and negative voltage respectively, or for storing electrical energy at different voltage levels, or for coupling different signal generation modules to provide electrical energy separately, and so on.

[0070] The first signal generating module 202 and the second signal generating module 203 are coupled to the master control module 201 respectively to obtain control signals to drive the switching devices respectively provided in the first signal generating module 202 and the second signal generating module 203 to perform an opening or closing action, and make the opening states of the two signal generating modules 202 and 203 mutually exclusive, and use the DC power obtained from the power supply module 101 or the DC energy supply module 206 to generate a first DC voltage signal and a second DC voltage signal with waveforms and time characteristics that comply with the control strategy, and make these two signals cooperate to output a DC pulse signal, which is provided to the load terminal 103 through the link 104.

[0071] In order to limit the simultaneous activation of the first signal generating module 202 and the second signal generating module 203 and avoid short circuit failures in the circuit during the signal generation process, a sensing module 204 is provided in the DC voltage signal control system for monitoring the working conditions of the first signal generating module 202 and the second signal generating module 203; an analysis and processing module 205 is also provided, which is coupled to the sensing module 204 and the main control module 201 respectively, to analyze the information measured by the sensing module 204 and feed back the analysis results to the main control module 201, and the main control module 201 sets the control signals output to the first signal generating module 202, the second signal generating module 203, etc. (such as maintaining existing instructions or updating instructions). Therefore, a feedback control module 402 is formed through the cooperation of the sensing module 204, the analysis and processing module 205 and the main control module 201.

[0072] For example, the analysis and processing module 205 analyzes and compares the monitoring information collected by the sensor module 204 from the two signal generating modules 202 and 203, determines whether a certain signal generating module is currently on or off, and determines whether one of the two signal generating modules is on and the other is off. The general control module 201 sets the control signal according to the judgment result to ensure that the on states of the first signal generating module 202 and the second signal generating module 203 are mutually exclusive, and generates a first DC voltage signal and a second DC voltage signal that do not overlap in the time domain. For another example, the analysis and processing module 205 analyzes and compares the monitoring information collected by the sensor module 204 from the two signal generation modules 202 and 203 (or further from the power supply module 101, the DC energy supply module 206, etc.) with the reference information pre-set in the control strategy to determine whether the monitoring information matches the reference information, so as to determine whether the current working state of the signal generation module complies with the configuration in the control strategy. Then, the master control module 201 generates a closed-loop control signal to implement feedback adjustment of the first signal generation module 202, the second signal generation module 203, etc., so as to accurately generate the signal waveform required by the semiconductor process.

[0073] Energy and / or information are transmitted through links 104 provided between the various modules of the DC voltage signal control system, as well as between the DC voltage signal control system and the load terminal 103. Links 104 can be equipped with devices such as electrical protection and signal isolation as needed. Each link 104 has a different physical form depending on the type of energy or information it carries, for example, including a transmission path based on at least one of electrical, mechanical, and optical methods. The first signal generation module 202 and the second signal generation module 203 each include a switching device controlled by, but not limited to, electricity, force, or light. The operating conditions of each switching device can be converted into one or more representations, such as electricity, force, or heat, and collected in real time by the corresponding sensor module 204.

[0074] As an example, the DC energy supply module 206, the first signal generation module 202, and the second signal generation module 203 cooperate to form the waveform generation module 401, which couples with the power module 101 and receives DC power through an electrical link. This electrical link, through which the waveform generation module 401 transmits the DC pulse signal to the load terminal 103, can be implemented, for example, using a DC cable capable of withstanding high voltages (e.g., tens of kilovolts). The link 104 used to transmit information can be a wired link, such as electrical cables connecting modules, traces on a printed circuit board, or various data communication buses (e.g., I2C, SPI, CAN, RS-485, etc.). It can also be a wireless communication link such as WiFi or Bluetooth, or an optical link such as an optical fiber or optocoupler, but is not limited thereto. The information transmitted can include, for example, control signals from the master control module 201, monitoring information collected by the sensor module 204, and analysis and processing results from the analysis and processing module 205. The switching devices of the first signal generating module 202 and the second signal generating module 203 may include, for example, electrically controlled switches such as transistors and relays, or hydraulic, pneumatic, or mechanically driven switching components, or light-controlled components such as photoresistors, but are not limited thereto. The sensing module 204 is equipped with corresponding types of sensors, such as those that monitor the temperature of the first signal generating module 202 and the second signal generating module 203, or the voltage or current on their respective output links 104, or directly monitor whether their respective switching devices have executed opening and closing actions, thereby obtaining monitoring information reflecting the operating conditions of the first signal generating module 202 and the second signal generating module 203.

[0075] In summary, the semiconductor processing equipment of this embodiment and the DC voltage signal control system therein use a high-voltage DC pulse signal instead of a low-frequency RF signal to form a bias voltage. Two complementary signal generation modules independently generate high-order pulse components and low-order pulse components, which can achieve higher switching frequencies and voltage slew rates, and perform targeted optimization of various parameters of different pulse components to accurately output pulse waveforms that meet semiconductor process requirements. The voltage is maintained at a relatively stable potential level within an adjustable time period to form a relatively stable electric field environment within the reaction chamber, thereby improving the continuity of the movement of charged particles in the plasma in the same direction. The key parameters in the signal generation process are monitored in real time by the sensing module, and the working status of the two complementary signal generation modules is automatically controlled in combination with a control strategy that strictly excludes the high and low potential conduction time domains, thereby avoiding short-circuit failures and improving the safety and stability of system operation.

[0076] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A DC voltage signal control system, characterized in that: Include: A power module is used to provide DC power; The first signal generating module, when in an on state, is used to obtain DC power and generate a first DC voltage signal; The second signal generating module, when in an on state, is used to obtain DC power and generate a second DC voltage signal; a master control module, coupled to the first signal generating module and the second signal generating module respectively; The control signal provided by the master control module includes an instruction for making the switching conditions of the first signal generating module and the second signal generating module mutually exclusive, so that the generated first DC voltage signal and the second DC voltage signal do not overlap in the time domain; Among them, the first signal generating module and the second signal generating module operate independently; the parameters of the first DC voltage signal and the parameters of the second DC voltage signal can be independently adjusted, and the parameters include waveform, amplitude, width and frequency; the on states of the first signal generating module and the second signal generating module are mutually exclusive, and the off states of the first signal generating module and the second signal generating module are mutually exclusive; the DC voltage signal control system provides the first DC voltage signal and the second DC voltage signal as bias voltages to the bias electrode in the base of the semiconductor processing equipment.

2. The DC voltage signal control system according to claim 1, wherein: Also includes: a DC energy supply module, the input end of which is coupled to the power supply module, and the output end of which is coupled to the first signal generating module and the second signal generating module respectively; The DC energy supply module stores the DC power obtained from the power supply module, and outputs the stored DC power to the first signal generation module or the second signal generation module in the turned-on state.

3. The DC voltage signal control system according to claim 1, wherein: Also includes: The sensing module is used to monitor the working conditions of the first signal generating module and the second signal generating module; the analysis and processing module is coupled with the sensing module and the master control module respectively, and is used to obtain the monitored parameters from the sensing module for analysis and processing, and feed back the results of the analysis and processing to the master control module, which sets the control signal.

4. The DC voltage signal control system according to claim 1, wherein: Each unit of the signal waveform of the first DC voltage signal includes a continuous first signal transition segment, a first signal maintaining segment, and a first signal returning segment: The voltage value in the first signal transition section is adjusted from the first reference value to within the threshold range of the first set value; the voltage value in the first signal holding section is within the threshold range of the first set value; and the voltage value in the first signal return section is adjusted from the threshold range of the first set value to the first reference value; Each unit of the signal waveform of the second DC voltage signal includes a continuous second signal transition segment, a second signal maintaining segment, and a second signal returning segment: The voltage value in the second signal transition segment is adjusted from the second reference value to the threshold range of the second set value; the voltage value in the second signal maintaining segment is within the threshold range of the second set value; the voltage value in the second signal return segment is adjusted from the threshold range of the second set value to the second reference value.

5. The DC voltage signal control system according to claim 4, characterized in that: The control signal provided by the master control module includes corresponding instructions for causing the first DC voltage signal and / or the second DC voltage signal to satisfy any one of the following or any combination thereof: The first DC voltage signal and the second DC voltage signal have the same or opposite voltage polarity; The first DC voltage signal and the second DC voltage signal have the same or different frequencies; The first DC voltage signal and the second DC voltage signal have the same or different duty cycles; The first reference value is the same as or different from the second reference value; The first set value and the second set value have the same or different absolute magnitudes; The upper threshold value of the first set value and the upper threshold value of the second set value have the same or different absolute values; The lower threshold limit of the first set value and the lower threshold limit of the second set value have the same or different absolute values; The first signal maintaining segment and the second signal maintaining segment have the same or different durations; The first signal transition segment and the second signal transition segment have the same or different durations; The first signal return segment and the second signal return segment have the same or different durations; The signal waveforms of adjacent units in the first DC voltage signal are the same or different; The signal waveforms of adjacent units in the second DC voltage signal are the same or different.

6. The DC voltage signal control system according to claim 5, characterized in that: The control signal provided by the master control module includes: An instruction is used to make the on state and the off state periodically switched by the first signal generating module mutually exclusive with the on state and the off state periodically switched by the second signal generating module, so that the first DC voltage signal and the second DC voltage signal are alternately generated to form a DC pulse signal, and the first DC voltage signal is the first pulse component of the DC pulse signal, and the second DC voltage signal is the second pulse component of the DC pulse signal.

7. The DC voltage signal control system according to claim 6, wherein: In the unit pulse waveform of the DC pulse signal, the duty cycle of the first signal maintaining segment and the duty cycle of the second signal maintaining segment are both within a set value range.

8. The DC voltage signal control system according to any one of claims 4 to 7, wherein: The first signal generating module outputs the DC voltage corresponding to the first signal maintaining section to the load terminal, or outputs the DC voltage corresponding to the first signal transition section, the first signal maintaining section, and the first signal returning section to the load terminal; The second signal generating module outputs the DC voltage corresponding to the second signal maintaining section to the load terminal, or outputs the DC voltage corresponding to the second signal transition section, the second signal maintaining section, and the second signal returning section to the load terminal.

9. The DC voltage signal control system according to claim 8, wherein: The first signal maintaining section of the first DC voltage signal and the second signal maintaining section of the second DC voltage signal provide the required bias voltage for the semiconductor processing equipment.

10. The DC voltage signal control system according to claim 1, wherein: Links for transmitting energy and / or information are respectively provided between the modules of the DC voltage signal control system, and between the DC voltage signal control system and the load terminals receiving the first DC voltage signal and the second DC voltage signal; the links include transmission paths based on at least one of electrical, mechanical, and optical forms.

11. A semiconductor processing apparatus comprising a vacuum reaction chamber with a base provided therein for supporting a substrate; a process gas introduced into the reaction chamber is excited by radio frequency energy coupled into the reaction chamber to form a plasma for processing the substrate; characterized in that: The DC voltage signal control system according to any one of claims 1 to 10 provides a first DC voltage signal and a second DC voltage signal that do not overlap in the time domain as bias voltages to the bias electrode in the base.

12. The semiconductor processing equipment according to claim 11, wherein The semiconductor processing equipment is used to implement a high aspect ratio etching process.

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