Semiconductor processing equipment and direct current voltage signal control system thereof

Abstract

The invention provides semiconductor processing equipment and a direct-current voltage signal control system thereof. According to the system, a first signal generation module and a second signal generation module are controlled to work independently, the starting states are mutually exclusive, direct-current electric energy is obtained to generate a first direct-current voltage signal and a second direct-current voltage signal which are not overlapped in a time domain, and the first direct-current voltage signal and the second direct-current voltage signal are provided for semiconductor processing equipment to form bias voltage; and the acceleration process of charged particles in the plasma is controlled. According to the invention, the system structure can be simplified, quick-response switch control can be realized, short circuit of a circuit can be prevented, the safety and stability of system operation can be improved, the flexibility of signal regulation and control can be enhanced, the pulse waveform can be optimized in a targeted manner, and the processing performance of semiconductor processing can be improved.

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 the market demand for advanced storage devices continues to expand, the requirements for semiconductor manufacturing processes are becoming more and more stringent, and the impact of voltage in the processing process is particularly important. In traditional semiconductor processing equipment, a high-frequency radio frequency signal is used to excite the neutral gas in the reaction chamber to generate plasma as the source of charged particles; another low-frequency radio frequency signal is used to form a strong negative bias to accelerate the positively charged particles in the reaction chamber, so that they quickly bombard the surface of the substrate to be processed to form the required micro-nano structure.

[0003] Taking the high aspect ratio etching process as an example, it is necessary to form a micro-nano structure with an etching depth much greater than the etching width on the substrate. In order to make the structural features meet expectations, high requirements are placed on process performance such as etching accuracy and speed. However, the traditional RF bias scheme has limitations in the development and use of this high aspect ratio etching process. For example, because the RF signal has the characteristics of alternating positive and negative amplitudes and periodic changes in intensity over time, the voltage is at its peak for a very short time, which causes the generated bias to be unable to maintain a stable maximum acceleration capacity in the process of accelerating charged particles, and the charged particle path is prone to deviation, affecting the processing accuracy. In addition, the modulation of the RF signal is relatively complex, and the design optimization of the RF source and the matching network is limited by factors such as component performance and control strategy, making it difficult to support rapid voltage adjustment; the bias change is synchronized with the waveform of the RF signal, and the frequency and periodic fluctuations of the RF signal limit the speed and flexibility of the bias adjustment. In addition, the charged particles in the plasma need time to respond to changes in the electric field, which will cause the actual effect of the bias adjustment to lag behind, and will not be able to meet the requirements of the bias control rate and voltage slew rate in the high aspect ratio process, affecting the efficiency and quality of etching. 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 improving the process performance of semiconductor processing.

[0005] A technical solution of the present invention is to provide a DC voltage signal control system, comprising: A power module, used for providing direct current power; The first signal generating module, when in an on state, is used to obtain direct current power and generate a first direct current voltage signal; The second signal generating module, when in the on state, is used to obtain direct current power and generate a second direct current voltage signal; 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.

[0006] Optionally, the DC voltage signal control system further comprises: A DC energy supply module, whose input end is coupled to the power supply module, and whose output end is respectively coupled to the first signal generating module and the second signal generating module; 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 which is in the on state.

[0007] Optionally, the DC voltage signal control system further comprises: A sensing module, 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 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.

[0008] 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: The voltage value in the first signal transition section is adjusted from the first reference value to the threshold range of the first set value; the voltage value in the first signal maintaining section is within the threshold range of the first set value; 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 within 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.

[0009] Optionally, the control signal provided by the master control module includes corresponding instructions to make the first DC voltage signal and / or the second DC voltage signal 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 limit of the first set value and the upper threshold limit 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 maintenance segment and the second signal maintenance 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.

[0010] 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.

[0011] 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.

[0012] Optionally, 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.

[0013] 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.

[0014] 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 a load terminal receiving the first DC voltage signal and the second DC voltage signal; the links include a transmission path based on at least one of electrical, mechanical, and optics.

[0015] 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 to support a substrate; the process gas introduced into the reaction chamber is excited by the radio frequency energy coupled to 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.

[0016] Optionally, the semiconductor processing equipment is used to implement a high aspect ratio etching process.

[0017] Compared with the prior art, the semiconductor processing equipment and the DC voltage signal control system provided by the present invention have at least the following beneficial effects: Different from the traditional method of forming bias through low-frequency RF signals, the method of using high-voltage DC signals for high-frequency pulse modulation in the embodiments of the present invention can maintain the voltage of the DC pulse signal near the voltage peak within an adjustable time period. The bias 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 capabilities.

[0018] In the embodiment of the present invention, the two signal generation modules work independently and can quickly respond to the control signal to perform their respective switching actions, thereby achieving a higher switching frequency and voltage slew rate. The exemplary DC voltage signal control system can stably and accurately generate a DC pulse voltage with a period in the microsecond or nanosecond level, meet the requirements for switching frequency and voltage slew rate in processes such as high aspect ratio etching, and provide etching rate and accuracy.

[0019] 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 non-overlapping pulse components 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 the semiconductor process.

[0020] 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, resulting in sparks and damage to the components in the system or reaction chamber, in the embodiments of the present invention, through the setting of control strategies and related algorithms, and the real-time monitoring of key parameters in the signal generation process by the sensor module, it is ensured that the opening states of the two signal generation modules are mutually exclusive, and the generated DC voltage signals do not overlap in the time domain, thereby avoiding the occurrence of short circuit faults and improving the safety and stability of system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a semiconductor processing device according to an embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of the composition structure of the DC voltage signal control system described in an embodiment of the present invention.

[0023] Figure 3 yes Figure 2 Schematic diagram of the composition structure of the medium and high voltage electrical signal controller.

[0024] Figure 4 It is a schematic diagram of the DC pulse signal waveform described in an embodiment of the present invention.

[0025] 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

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0027] like Figure 1As shown, the semiconductor processing equipment of this embodiment includes a vacuumable reaction chamber 10, which is provided with a roughly cylindrical metal cavity; the side wall of the cavity is provided with an opening (not shown in the figure), which can be used by the robot to carry the substrate w in and out of the reaction chamber 10. A base 20 with an electrostatic chuck is provided in the reaction chamber 10 to carry the substrate w. The source RF power (frequency range is, for example, 100kHz-200MHz) provided by the RF source 30 is coupled to the reaction chamber 10 to excite the process gas injected into the cavity to form a plasma. The plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals. The above-mentioned active particles can undergo various physical and chemical reactions with the surface of the substrate w, so that the morphology of the surface of the substrate w changes, and the etching of the substrate w is completed. The vacuum pump 50 connected to the reaction chamber 10 can discharge the residual gas, reaction by-products, etc. after treatment from the reaction chamber 10 to maintain the vacuum environment in the cavity.

[0028] 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, which is arranged opposite to the base 20 serving as a lower electrode. The RF source 30 is connected to the upper electrode and / or the lower electrode to apply source RF power, thereby generating a RF electric field between the upper electrode and the lower electrode to dissociate the process gas in the chamber into plasma.

[0029] 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 reaction machine containing a base 20; the bias electrode in the base 20 receives the DC pulse signal and forms a bias voltage in the reaction chamber 10 to control the acceleration process of the charged particles in the plasma bombarding the substrate w. Compared with the original scheme of generating bias voltage by a low-frequency radio frequency signal, the DC pulse signal used in the present invention can maintain the voltage near the preset voltage peak value within an adjustable time period. The bias voltage thus obtained forms a relatively stable electric field environment in the reaction chamber 10, so that the charged particles can obtain continuous maximum acceleration capability under the action of the electric field, and the acceleration path of the charged particles can be kept consistent, effectively improving the accuracy and efficiency of plasma processing of the substrate w.

[0030] like Figure 2 , Figure 3As shown, the DC voltage signal control system is provided with a high-voltage electric signal controller 102, which is coupled to a power module 101 and a load terminal 103 respectively through corresponding links 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. Among them, 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.

[0031] Furthermore, the instructions included in the control signal are also used to periodically switch the on state and the off state of the first signal generating module 202, periodically switch the on state and the 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 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.

[0032] 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 and the like 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 signal generating module 202 and the second signal generating module 203 are directly connected to each other to prevent a short circuit in the circuit, so that the output DC pulse signal is more stable, thereby 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, which is convenient for the subsequent feedback adjustment of the parameters of the first DC voltage signal and the second DC voltage signal; 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 the parts of their respective pulse components, so that they can quickly respond to the control signal sent by the master control module 201 to execute the switching action required to generate the DC voltage signal, effectively reduce the switching delay, and enable the output DC pulse signal to quickly switch between the voltage states corresponding to the different pulse components, thereby improving the dynamic response performance of the entire system.

[0033] For example, when semiconductor processing equipment is used in a high aspect ratio etching process, it is necessary to form a micro-nano structure with an etching depth much greater than the etching width on the substrate w; 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 achieve high-quality microelectronic device manufacturing.

[0034] The first DC voltage signal, the second DC voltage signal, and a DC pulse signal formed by the cooperation of the first DC voltage signal and the second DC voltage signal are schematically described below.

[0035] 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.

[0036] Under the control strategy of the master control module 201 and the corresponding control signals, the first DC voltage signal and the second DC voltage signal may have independently adjustable parameters, including but 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.

[0037] In different examples, for the same unit pulse waveform, the first DC voltage signal and the second DC voltage signal may have the same or different configurations of the same-name parameter items; in adjacent unit pulse waveforms, the first DC voltage signal may have the same or different configurations of the same-name parameter items, so that the signal 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 may have the same or different configurations of the same-name parameter items, so that the signal waveforms of the second DC voltage signal in adjacent units are the same or different. In this way, a DC pulse signal with a signal waveform, time characteristics, etc. that meets the setting can be obtained to form the bias voltage required by the semiconductor process requirements. 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, etc. 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.

[0038] 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, and 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 section 301; the voltage remains above the first set value 308 for a period of time t2, forming a first signal maintaining section 302; the voltage 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 section 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 (t4~t6) of the unit pulse waveform, so that the voltage continues to drop from the reference potential 307, and reaches the second set value 309 after the falling time t4, forming a second signal transition section 304; the voltage is kept below the second set value 309 for a holding time t5, forming a second signal holding section 305; the voltage starts to rise from the second set value 309 again, and returns to the reference potential 307 after the rising 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.

[0039] In this example, the voltage value is within the threshold range of the first set value 308, which means that the absolute amplitude of the voltage in the first signal maintenance section 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 section 302 can fluctuate slightly within the threshold range, or can remain unchanged at a certain high pulse value at or above the first set value 308); the voltage value is within the threshold range of the second set value 309, which means that the absolute amplitude of the voltage in the second signal maintenance section 305 is between the second set value 309 and the voltage of the DC power (the voltage value in the second signal maintenance section 305 can fluctuate slightly within the threshold range, or can remain unchanged at a certain low pulse value at or below the second set value 309). The high pulse value and the low pulse value can have the same voltage polarity; or, one of the pulse values ​​can be set to 0; or, the high pulse value and the low pulse value can have opposite voltage polarities (and the first set value 308 and the second set value 309 can 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 the high / low pulse value, etc. can all be adjusted according to actual needs, and the present invention does not impose any limitation on this.

[0040] 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 setting the duration of each signal transition segment, maintenance segment, and return segment, each set value and its threshold range, etc., the waveform and time characteristics of the first DC voltage signal and the second DC voltage signal can be regulated. As an example, if the voltage values ​​in the first signal maintenance segment and the second signal maintenance segment are respectively maintained at the high pulse value and the low pulse value, the waveform of the DC pulse signal finally output is similar to a trapezoidal wave or a rectangular wave (the signal transition segments and return segments of the trapezoidal wave have their own set slopes, while the duration of the signal transition segments and return segments of the rectangular wave is extremely short).

[0041] It can be seen that, compared with the signal transition segments 301, 304 or the signal return segments 303, 306, whose voltage values ​​vary greatly, 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 a relatively stable potential level, respectively. 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 the expected energy gain, thereby accurately and efficiently controlling the acceleration process of the charged particles. Therefore, in the output DC pulse signal, the duty ratios of the first signal maintaining segment 302 and the second signal maintaining segment 305 in the unit pulse waveform are within the set value range (such as the first signal maintaining segment 302 and the second signal maintaining segment 305 have a duty ratio of 1% or more, respectively), and the bias voltage obtained thereby can improve the movement continuity of the charged particles in the same direction and improve 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 side wall roughness and morphology deviation, and obtain a more uniform etching effect.

[0042] 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 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 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.

[0043] The following is 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 the 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 module 101 is used to provide the DC power required to generate the DC pulse signal, and can also power other modules in need in the system; the power module 101, for example, includes a power adapter that can convert external AC power into the DC power required by the system, or includes a DC converter that can convert other DC voltage levels into the DC voltage level required by the system.

[0044] In some examples, the first signal generating module 202 and the second signal generating 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, a DC energy supply module 206 is provided in the system to assist the power module 101 in providing stable DC power and cooperate with the first signal generating module 202 and the second signal generating module 203 to form a waveform generating module 401; the DC energy supply module 206 includes an energy storage device (for example, a capacitor or a battery, etc.), and its input end is coupled to the power module 101 through 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 generating module 202 and the second signal generating module 203 respectively, and the stored DC power is provided to the first signal generating module 202 or the second signal generating module 203 in the turned-on state. The exemplary DC energy supply module 206 may be provided with a set of energy storage devices; or, 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.

[0045] 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 switch 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 meet 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.

[0046] In order to limit the simultaneous start-up 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 sensor 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 sensor module 204 and the main control module 201 respectively, analyzes the information measured by the sensor module 204, and feeds 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), thereby forming a feedback control module 402 through the cooperation of the sensor module 204, the analysis and processing module 205 and the main control module 201.

[0047] 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 turned on or off, and determines whether one of the two signal generating modules is turned on and the other is turned off. The general control module 201 sets a 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 generating 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 generating module complies with the configuration in the control strategy. The general control module 201 then generates a closed-loop control signal to implement feedback adjustment of the first signal generating module 202, the second signal generating module 203, etc., so as to accurately generate the signal waveform required by the semiconductor process.

[0048] The link 104 provided between the modules of the DC voltage signal control system and the link 104 provided between the DC voltage signal control system and the load terminal 103 is used to transmit energy and / or information, and the link 104 may be equipped with devices such as electrical protection and signal isolation as needed; each link 104 has different physical forms according to the type of energy or information carried, for example, including a transmission path based on at least one of electricity, mechanics, and optics. The first signal generating module 202 and the second signal generating module 203 are each provided with a switch device controlled in a form not limited to electricity, force, light, etc., and the working conditions of each switch device can be converted into one or more representation forms such as electricity, force, heat, etc., and collected in real time by the corresponding type of sensor module 204.

[0049] As an example, the waveform generation module 401 formed by the DC energy supply module 206, the first signal generation module 202, and the second signal generation module 203 is coupled with the power module 101 to receive the electrical link of DC power. The electrical link of the waveform generation module 401 transmitting the DC pulse signal to the load terminal 103 is realized by, for example, using a DC cable that can withstand high voltage (for example, tens of thousands of volts). The link 104 for transmitting information can be a wired link, such as an electrical connection line connected between modules, a wiring on a printed circuit board, various data communication buses (such as I2C, SPI, CAN, RS-485, etc.), or a link of various wireless communications such as WiFi, Bluetooth, or an optical link using optical fiber, photoelectric coupler, etc., and is not limited thereto. The information transmitted is, for example, a control signal sent by the master control module 201, monitoring information collected by the sensor module 204, and the analysis and processing results of the analysis and processing module 205. The switch devices of the first signal generating module 202 and the second signal generating module 203 include, for example, electric control switches such as transistors and relays, or switch components of hydraulic, pneumatic or mechanical transmission, or light control components such as photoresistors, but are not limited thereto. The sensing module 204 is equipped with sensors of corresponding types, such as monitoring the respective temperatures of the first signal generating module 202 and the second signal generating module 203, or monitoring the voltage or current on their respective output links 104, or directly monitoring whether their respective switch devices have performed opening and closing actions, etc., to obtain monitoring information reflecting the working conditions of the first signal generating module 202 and the second signal generating module 203.

[0050] In summary, the semiconductor processing equipment of this embodiment and the DC voltage signal control system therein use a high-voltage DC pulse signal to replace 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 optimize various parameters of different pulse components in a targeted manner to accurately output pulse waveforms that meet the requirements of semiconductor processes; the voltage is maintained at a relatively stable potential level within an adjustable time period, so as to form a relatively stable electric field environment in the reaction chamber, and improve the continuity of 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 control strategy of strict mutual exclusion of high and low potential conduction time domains is combined to automatically control the working states of the two complementary signal generation modules to avoid short-circuit faults and improve the safety and stability of system operation.

[0051] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A DC voltage signal control system, characterized in that: Include: A power module, used for providing direct current power; The first signal generating module, when in an on state, is used to obtain direct current power and generate a first direct current voltage signal; The second signal generating module, when in the on state, is used to obtain direct current power and generate a second direct current 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 start states of the first signal generation module and the second signal generation module mutually exclusive, so that the generated first DC voltage signal and the second DC voltage signal do not overlap in the time domain.

2. The DC voltage signal control system according to claim 1, characterized in that: Also includes: A DC energy supply module, whose input end is coupled to the power supply module, and whose output end is respectively coupled to the first signal generating module and the second signal generating module; 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 which is in the on state.

3. The DC voltage signal control system according to claim 1, characterized in that: Also includes: A sensing module, 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 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.

4. The DC voltage signal control system according to claim 1, characterized in that: 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 the threshold range of the first set value; the voltage value in the first signal maintaining section is within the threshold range of the first set value; 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 within 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 to make the first DC voltage signal and / or the second DC voltage signal 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 limit of the first set value and the upper threshold limit 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 maintenance segment and the second signal maintenance 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 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.

7. The DC voltage signal control system according to claim 6, characterized in that: 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, characterized in that: 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, characterized in that: 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.

10. The DC voltage signal control system according to claim 1, characterized in that: 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 a transmission path based on at least one form of electricity, mechanics, and optics.

11. A semiconductor processing device comprising a vacuum reaction chamber, wherein a base is provided inside the chamber to carry a substrate; The process gas introduced into the reaction chamber is excited by the radio frequency energy coupled into the reaction chamber to form a plasma for processing the substrate; the process gas is characterized in that: The DC voltage signal control system described in 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 a 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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