Electron beam scanning equipment and voltage regulating circuit thereof

Abstract

The invention provides electron beam scanning equipment and a voltage regulation circuit thereof. The voltage regulation circuit is used for providing set voltage for a power supply module of the electron beam scanning equipment, and comprises a signal source, a driving control unit and a voltage regulation unit, the signal source is configured to output an initial control signal to the driving control unit; the driving control unit is connected with the signal source, and is configured to receive the initial control signal, sample the output voltage of the voltage regulation unit to generate a feedback signal, and generate a driving signal by comparing the difference between the initial control signal and the feedback signal; the voltage adjusting unit is connected with the driving control unit and is configured to receive the driving signal and adjust the working state of the voltage adjusting unit according to the driving signal so as to output positive and negative voltages which can be continuously adjusted within a preset range. The method has the advantages that the adjusting time of the high voltage can be shortened, the voltage adjusting speed is increased, and the image acquisition requirement of electron beam rapid scanning is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic scanning, in particular to an electron beam scanning device and a voltage adjusting circuit thereof. BACKGROUND

[0002] In the field of electronic scanning, in order to achieve the goal of fast focusing, it is often necessary to quickly adjust the conditions related to focusing. One of the common ways is to change the parameters of the high-voltage power supply, which is characterized by quickly changing the output voltage of the high-voltage power supply to achieve the purpose of fast focusing. Currently, in the application of high-voltage power supply, when it is necessary to set the voltage at any point within the range of 10kv±100V, the time required for the entire voltage setting process reaches the order of 10ms. In the fast scanning scenario, such time cost will seriously restrict the image acquisition speed, and it is difficult to meet the actual needs of efficient scanning. The root cause of this problem lies in the design of the high-voltage power supply, which is limited by the current technical level, and its setting time cannot be reduced to the order of microseconds, which has become the main shortcoming of this method in fast scanning applications. In addition to changing the high-voltage power supply, changing the magnetic field to achieve focusing adjustment is also a common method. However, this method also has obvious shortcomings. The time required for magnetic field change is also in the order of milliseconds, and the long response time makes it difficult to adapt to the requirements of fast scanning. Moreover, there is a magnetic hysteresis phenomenon in the process of magnetic field change, which will directly lead to a decrease in the accuracy of the focusing setting, and thus affect the overall effect of electronic scanning. SUMMARY

[0003] An object of the present application is to overcome at least one technical defect in the prior art, and to provide an electron beam scanning device and a voltage adjusting circuit thereof.

[0004] A further object of the present application is to shorten the adjustment time of the high-voltage, improve the voltage adjustment speed, and meet the image acquisition needs of fast scanning of the electron beam.

[0005] Another further object of the present application is to improve the accuracy of voltage adjustment, avoid the setting deviation caused by the magnetic hysteresis phenomenon in the existing magnetic field adjustment method, and ensure the stability of the focusing state.

[0006] Still another further object of the present application is to simplify the circuit structure, to achieve fast adjustment, and to reduce circuit noise and improve work reliability by integrating filtering and protection functions.

[0007] In particular, according to a first aspect of the present application, the present application provides a voltage adjusting circuit for providing a setting voltage to a power module of an electron beam scanning device, comprising: a signal source, a driving control unit, and a voltage adjusting unit. The signal source is configured to output an initial control signal to the drive control unit; The drive control unit is connected with the signal source and is configured to receive the initial control signal and sample the output voltage of the voltage regulation unit to generate a feedback signal, and generate a drive signal by comparing the difference between the initial control signal and the feedback signal; The voltage regulation unit is connected with the drive control unit and is configured to receive the drive signal and adjust its working state according to the drive signal to output positive and negative voltages within a preset range that can be continuously adjusted.

[0008] Optionally, the drive control unit comprises a feedback sampling circuit and an operational amplifier; The feedback sampling circuit is connected with the voltage regulation unit and is configured to sample the positive and negative voltages output by the voltage regulation unit to generate a feedback signal and output the feedback signal to the operational amplifier; The operational amplifier is connected with the signal source and the feedback sampling circuit and is configured to receive the initial control signal output by the signal source and the feedback signal output by the feedback sampling circuit, generate a corresponding drive signal by comparing the difference between the initial control signal and the feedback signal, and output the drive signal to the voltage regulation unit to regulate the positive and negative voltages output by the voltage regulation unit.

[0009] Optionally, the feedback sampling circuit comprises a first sampling resistor, a second sampling resistor, and a sampling capacitor; One end of the first sampling resistor is connected with the output end of the voltage regulation unit, and the other end is connected with the second sampling resistor, which is used to sample the positive and negative voltages output by the voltage regulation unit in cooperation with the second sampling resistor; the sampling capacitor is connected in parallel to both ends of the first sampling resistor, which is used to filter the sampling signal obtained by the voltage division sampling to form the feedback signal and output the feedback signal to the operational amplifier.

[0010] Optionally, the operational amplifier has a non-inverting input end, an inverting input end, and a signal output end, the non-inverting input end is connected with the signal source, the inverting input end is connected with the feedback sampling circuit, and the signal output end is connected with the voltage regulation unit.

[0011] Optionally, the voltage regulation unit comprises a first regulation tube and a second regulation tube; The first end of the first regulation tube is connected with a positive reference power supply, the second end is connected with the operational amplifier, and the third end is connected with the output end of the voltage regulation unit; The first end of the second regulation tube is connected with a negative reference power supply, the second end is connected with the operational amplifier, and the third end is connected with the output end of the voltage regulation unit. The first regulating transistor is configured to adjust the output amplitude of the positive reference voltage under the action of the driving signal, and the second regulating transistor is configured to adjust the output amplitude of the reverse reference voltage under the action of the driving signal, so that the output terminal of the voltage regulating unit outputs a continuously adjustable positive and negative voltage within a preset range.

[0012] Optionally, the voltage regulation unit further includes a third regulating tube; The first end of the third regulating transistor is grounded, the second end of the third regulating transistor is connected to the operational amplifier, and the third end of the third regulating transistor is connected to the second end of the first regulating transistor and the second end of the second regulating transistor, respectively. The third regulating transistor is configured to control its conduction and cutoff under the combined action of the driving signal and its own conduction threshold. When the third regulating transistor is on, the first regulating transistor, the second regulating transistor, and the operational amplifier are on, allowing the output of regulated positive and negative voltages. When the driving signal causes the third regulating transistor to be cut off, the first regulating transistor, the second regulating transistor, and the operational amplifier are disconnected.

[0013] Optionally, the first regulating transistor is a PNP transistor, with its first terminal being the collector, its second terminal being the base, and its third terminal being the emitter; The second regulating transistor is an NPN transistor, with its first terminal being the emitter, the second terminal being the base, and the third terminal being the collector.

[0014] Optionally, the voltage regulation circuit further includes: A filter protection circuit, which includes a first filter capacitor and a second filter capacitor; One end of the first filter capacitor is connected to the positive reference power supply, and the other end is grounded, which is used to filter the positive voltage output by the voltage regulation unit; One end of the second filter capacitor is connected to the reverse reference power supply, and the other end is grounded, which is used to filter the reverse voltage output by the voltage regulation unit.

[0015] Optionally, the filter protection circuit further includes a first diode and a second diode; The first diode is connected in parallel between the first and third terminals of the first regulating transistor to provide freewheeling protection in the forward voltage regulation path and suppress reverse overvoltage during turn-off. The second diode is connected in parallel between the first and third terminals of the second regulating transistor to provide freewheeling protection in the reverse voltage regulation path and suppress reverse overvoltage during turn-off.

[0016] According to a second aspect of the present invention, an electron beam scanning device is provided, comprising the voltage regulation circuit, power supply module, and focusing mechanism described in any one of the above-described embodiments; The power module is connected to the focusing mechanism, and the voltage regulation circuit is connected to the power module. The voltage regulation circuit is configured to regulate the output voltage of the power module by outputting a continuously adjustable positive and negative voltage, so that the power module outputs an appropriate working voltage to the focusing mechanism.

[0017] The voltage regulation circuit of the present invention can significantly shorten the voltage regulation time and meet the imaging requirements of rapid electron beam scanning because it outputs a continuously adjustable positive and negative voltage within a preset range through the voltage regulation unit, without relying on the slow-responding high-voltage power supply or magnetic field regulation in the prior art.

[0018] Furthermore, the voltage regulation circuit of the present invention, through real-time sampling of the output voltage by the feedback sampling circuit in the drive control unit and comparison of the difference between the initial control signal and the feedback signal by the operational amplifier, can dynamically correct the voltage output deviation, improve the accuracy of voltage regulation, and avoid setting deviation caused by hysteresis.

[0019] Furthermore, the voltage regulation circuit of the present invention integrates a filter protection circuit including a filter capacitor and a protection diode. The filter capacitor can reduce output voltage noise, and the protection diode can suppress reverse overvoltage when the regulating tube is turned off, which can improve the reliability of operation while simplifying the circuit structure.

[0020] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of an electron beam scanning device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a voltage regulation circuit according to an embodiment of the present invention; Figure 3 This is a topology diagram of a voltage regulation circuit according to an embodiment of the present invention; Figure 4 yes Figure 3 The diagram shows the continuously adjustable voltage waveform output by the voltage regulation circuit. Detailed Implementation

[0022] Reference will now be made in detail to embodiments of the invention, one or more of which are illustrated in the accompanying drawings. The various embodiments provided are intended to explain the invention and not to limit it. In fact, various modifications and variations to the invention will be apparent to those skilled in the art without departing from the scope or spirit of the invention. For example, a feature illustrated or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover such modifications and variations within the scope of the appended claims and their equivalents.

[0023] In the description of this embodiment, it should be understood that the term "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. When a feature "includes or contains" one or more of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may be further included.

[0024] In the description of this embodiment, the terms "one embodiment," "some embodiments," "some examples," "one example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0025] In the semiconductor manufacturing industry, the surface quality of wafers plays a decisive role in the performance, reliability, and yield of chips. As semiconductor technology rapidly advances towards smaller sizes and higher performance, extremely stringent requirements are placed on the accuracy and efficiency of wafer surface defect detection. Electron beam scanning equipment, with its high resolution and high sensitivity, can accurately detect extremely small defects, making it an indispensable key device in wafer surface defect detection.

[0026] Figure 1 This is a schematic diagram of an electron beam scanning device 1 according to an embodiment of the present invention. Figure 1 As shown, the electron beam scanning device 1 may include a voltage regulation circuit 10, a power supply module 20, and a focusing mechanism 30.

[0027] The focusing mechanism 30 is the core component in the electron beam scanning device 1 that controls the focusing state of the electron beam. During operation, the electron beam is emitted from the electron gun. The focusing mechanism 30 applies precise electromagnetic force to the electron beam, altering its trajectory and regulating its spatial shape. This allows the initially dispersed electron beam to gradually converge, forming a tiny, highly concentrated focal point at a specific location. Simultaneously, the focusing mechanism 30 also finely controls the energy distribution of the electron beam, preventing excessive energy dispersion or localized overheating, ensuring that the energy carried by the electron beam is applied uniformly and efficiently to the wafer surface.

[0028] The power module 20 is connected to the focusing mechanism 30, providing the focusing mechanism 30 with a basic operating voltage (e.g., 10kV high voltage), which is the key energy source for driving the focusing mechanism 30 to achieve electron beam focusing. Such a high voltage can give the electron beam enough energy, so that it can be directed towards the wafer surface with extremely high speed and precision under the control of the focusing mechanism 30.

[0029] The voltage regulation circuit 10 is connected to the power supply module 20 and is used to provide the setting voltage to the power supply module 20. During the electronic scanning process, rapid adjustment of the high-voltage power supply is required to achieve rapid focusing. The voltage regulation circuit 10 of the present invention can dynamically regulate the output voltage of the power supply module 20 by outputting a continuously adjustable positive and negative voltage within a preset range (e.g., ±100V), so that the power supply module 20 outputs an appropriate working voltage to the focusing mechanism 30, ultimately achieving rapid switching of the electron beam focusing state.

[0030] Taking a common scenario in actual testing as an example, when testing different areas of a wafer or wafers at different process nodes, the focusing requirements of the focusing mechanism 30 for the electron beam will change. At this time, the voltage regulation circuit 10 will adjust the output voltage in real time. Through dynamic interaction with the power supply module 20, the power supply module 20 outputs an appropriate working voltage to the focusing mechanism 30, ensuring that the focusing mechanism 30 can flexibly and quickly switch the electron beam focusing state, thereby meeting the requirements of high-speed and high-precision wafer surface defect detection and providing strong and stable voltage regulation support for the entire testing process.

[0031] Figure 2 This is a schematic diagram of a voltage regulation circuit 10 according to an embodiment of the present invention, as shown below. Figure 2 As shown, the voltage regulation circuit 10 may include a signal source 110, a drive control unit 120, and a voltage regulation unit 130.

[0032] Signal source 110 is configured to output an initial control signal to drive control unit 120. Drive control unit 120 is connected to signal source 110, configured to receive the initial control signal, and sample the output voltage of voltage regulation unit 130 to generate a feedback signal. Drive signal is generated by comparing the difference between the initial control signal and the feedback signal. Voltage regulation unit 130 is connected to drive control unit 120, configured to receive the drive signal, and adjust its own working state according to the drive signal to output a continuously adjustable positive and negative voltage within a preset range.

[0033] Understandably, signal source 110, as the initiating unit of voltage regulation command, outputs initial control signals (such as voltage signals, current signals, etc.) to drive control unit 120. The initial control signals directly map to the final target regulation voltage (such as preset values ​​such as +50V, -30V, etc.) and serve as the original control basis for the entire voltage regulation process, used to clarify the direction (forward or reverse) and amplitude (the specific size of the regulation voltage) of the voltage regulation.

[0034] The drive control unit 120 serves as an intermediate unit for signal conversion and drive execution. One end is connected to the signal source 110 to receive the initial control signal, and the other end is connected to the voltage regulation unit 130. By processing the initial control signal output from the signal source 110, it generates a drive signal that meets the operating requirements of the voltage regulation unit 130. In other words, through signal adaptation, the initial control signal and feedback signal representing the voltage regulation command are converted into drive signals that the voltage regulation unit 130 can directly recognize and respond to.

[0035] The voltage regulation unit 130, as the voltage output execution unit, can dynamically adjust its own operating state according to the received drive signal, and finally output a continuously variable positive and negative voltage within a preset range to the outside. For example, when the drive signal transmits the instruction to "increase the positive output voltage", the unit increases the positive voltage output amplitude by increasing the conductivity of the positive path; when the drive signal transmits the instruction to "switch to reverse voltage output", the unit achieves stable reverse voltage output by switching the internal circuit path.

[0036] The voltage regulation circuit 10 of the present invention can significantly shorten the voltage regulation time and meet the imaging requirements of rapid electron beam scanning because it outputs a continuously adjustable positive and negative voltage within a preset range through the voltage regulation unit 130, without relying on the slow-responding high-voltage power supply or magnetic field regulation in the prior art.

[0037] In an optional embodiment, the drive control unit 120 may include a feedback sampling circuit 121 and an operational amplifier U1. The feedback sampling circuit 121 is connected to the voltage regulation unit 130 and is configured to sample the positive and negative voltages output by the voltage regulation unit 130, generate a feedback signal, and output it to the operational amplifier U1. The operational amplifier U1 is connected to the signal source 110 and the feedback sampling circuit 121 and is configured to receive the initial control signal output by the signal source 110 and the feedback signal output by the feedback sampling circuit 121. By comparing the difference between the initial control signal and the feedback signal, a corresponding drive signal is generated and output to the voltage regulation unit 130 to regulate the positive and negative voltages output by the voltage regulation unit 130.

[0038] It is understandable that one end of the feedback sampling circuit 121 is connected to the output terminal of the voltage regulation unit 130, enabling real-time sampling of the positive and negative voltages output by the voltage regulation unit 130. By acquiring the actual value of the output voltage and performing signal conversion processing, a feedback signal proportional to the output voltage is generated. This feedback signal is then transmitted to the operational amplifier U1 to provide an actual state reference for voltage regulation.

[0039] Operational amplifier U1 is connected to both signal source 110 and feedback sampling circuit 121. It receives both the initial control signal (representing the target voltage value) from signal source 110 and the feedback signal (representing the actual output value) from feedback sampling circuit 121. By performing difference calculations on these two signals, the deviation between the target and actual values ​​can be obtained. Finally, a corresponding drive signal is generated based on this deviation and output to voltage regulation unit 130. In this way, the positive and negative voltages output by voltage regulation unit 130 can be dynamically controlled, ensuring that the actual output value matches the target value and achieving high-precision voltage regulation.

[0040] Thus, the voltage regulation circuit 10 of the present invention forms a closed-loop control link from deviation detection to signal correction and then to drive regulation. Even if the actual output fluctuates due to circuit noise or load changes, the operational amplifier U1 can quickly detect the deviation and correct it to ensure that the output voltage is stable near the target value.

[0041] Figure 3 This is a topology diagram of a voltage regulation circuit according to an embodiment of the present invention, such as... Figure 3As shown, the feedback sampling circuit 121 may include a first sampling resistor R2, a second sampling resistor R3, and a sampling capacitor C4. One end of the first sampling resistor R2 is connected to the output terminal of the voltage regulation unit 130, and the other end is connected to the second sampling resistor R3. It is used to cooperate with the second sampling resistor R3 to perform voltage division sampling of the positive and negative voltages output by the voltage regulation unit 130. The sampling capacitor C4 is connected in parallel across the two ends of the first sampling resistor R2. It is used to filter the sampling signal obtained by voltage division sampling, form a feedback signal, and output it to the operational amplifier U1.

[0042] It is understandable that the first sampling resistor R2 and the second sampling resistor R3 form a series voltage divider network. When the voltage regulation unit 130 outputs positive or negative voltage, this series voltage divider network will divide the output voltage according to the resistance value ratio, converting the high-amplitude output voltage into a low-voltage signal that the operational amplifier U1 can safely receive and process, while preserving the positive and negative characteristics and proportional relationship of the voltage, ultimately ensuring that the sampled signal can truly reflect the actual output state.

[0043] Sampling capacitor C4 is connected in parallel across the first sampling resistor R2, primarily for filtering the voltage-divided sampling signal. Since the output voltage of the voltage regulation unit 130 may fluctuate slightly due to factors such as circuit switching and component noise, these fluctuations can cause interference components in the sampling signal. Sampling capacitor C4 absorbs high-frequency ripple through its charging and discharging characteristics, making the voltage-divided signal smoother and more stable. This results in a clean and accurate feedback signal that is transmitted to operational amplifier U1, providing a reliable basis for subsequent deviation comparisons. This avoids operational amplifier U1 misjudging the deviation due to noise interference, further improving the accuracy and stability of the closed-loop regulation.

[0044] Operational amplifier U1 has a non-inverting input, an inverting input, and a signal output. The non-inverting input is connected to signal source 110 to receive the initial control signal output by signal source 110; the inverting input is connected to feedback sampling circuit 121 to receive the feedback signal output by feedback sampling circuit 121; and the signal output is connected to voltage regulation unit 130 to output the corresponding drive signal to voltage regulation unit 130.

[0045] In some embodiments, the voltage regulation unit 130 may include a first regulating transistor Q1 and a second regulating transistor Q2. The first regulating transistor Q1 has a first terminal connected to a positive reference power supply, a second terminal connected to an operational amplifier U1, and a third terminal connected to the output terminal of the voltage regulation unit 130. The second regulating transistor Q2 has a first terminal connected to a reverse reference power supply, a second terminal connected to the operational amplifier U1, and a third terminal connected to the output terminal of the voltage regulation unit 130. The first regulating transistor Q1 is configured to adjust the output amplitude of the positive reference voltage under the action of a drive signal, and the second regulating transistor Q2 is configured to adjust the output amplitude of the reverse reference voltage under the action of a drive signal, thereby enabling the output terminal of the voltage regulation unit 130 to output a continuously adjustable positive and negative voltage within a preset range.

[0046] It is understandable that the first regulating transistor Q1 and the second regulating transistor Q2 control the output amplitude of the forward / reverse voltage respectively by receiving the drive signal output from the operational amplifier U1. Specifically, when the operational amplifier U1 outputs a forward drive signal (such as a high level), the first regulating transistor Q1 is driven to conduct, and its conduction degree is determined by the amplitude of the drive signal. The stronger the drive signal, the higher the conduction degree, and the larger the amplitude of the forward voltage introduced from the forward reference power supply. At this time, the second regulating transistor Q2 is in the off state and does not affect the forward voltage output. When the operational amplifier U1 outputs a reverse drive signal (such as a low level), the second regulating transistor Q2 is driven to conduct, and its conduction degree is also controlled by the drive signal. The larger the reverse amplitude of the drive signal, the higher the conduction degree, and the larger the amplitude of the reverse voltage introduced from the reverse reference power supply. At this time, the first regulating transistor Q1 is in the off state and does not affect the reverse voltage output.

[0047] This design, by separating the adjustment paths for positive and reverse voltages, can ensure the independent control accuracy of positive and negative voltages, while also enabling collaborative operation through shared drive signals, ultimately meeting the rapid, continuous, and bidirectional adjustment requirements of the electron beam scanning device for the focusing voltage.

[0048] In some embodiments, the voltage regulation unit 130 may further include a third regulating transistor Q3, the first end of which is grounded, the second end of which is connected to the operational amplifier U1, and the third end of which is connected to the second end of the first regulating transistor Q1 and the second end of the second regulating transistor Q2. The third regulating transistor Q3 is configured to control the on and off states under the combined action of the drive signal and its own conduction threshold. When the third regulating transistor Q3 is on, the first regulating transistor Q1, the second regulating transistor Q2 and the operational amplifier U1 are on, allowing the regulated positive and negative voltages to be output. When the drive signal causes the third regulating transistor Q3 to be off, the first regulating transistor Q1, the second regulating transistor Q2 and the operational amplifier U1 are disconnected.

[0049] Understandably, the conduction and cutoff of the third regulating transistor Q3 are entirely determined by the amplitude of the drive signal output by operational amplifier U1 and its own conduction threshold. When the third regulating transistor Q3 is in the conducting state, the drive signal of operational amplifier U1 can be transmitted through the path of the third regulating transistor Q3 to the first regulating transistor Q1 and the second regulating transistor Q2, causing the first regulating transistor Q1 and the second regulating transistor Q2 to adjust their conduction degree according to the drive signal, and finally output the regulated positive and negative voltages. When the third regulating transistor Q3 is in the cutoff state, the drive signal of operational amplifier U1 cannot be transmitted to the first regulating transistor Q1 and the second regulating transistor Q2. The first regulating transistor Q1 and the second regulating transistor Q2 are in the cutoff state due to the lack of a drive signal, and there is no voltage output at the output terminal of the voltage regulation unit 130, which is equivalent to the entire regulation link being shut down.

[0050] In this way, when the electron beam scanning device 1 does not require adjustment of the focusing voltage, the drive signal output by the operational amplifier U1 will be lower than the conduction threshold of the third regulating transistor Q3, causing it to be cut off. At this time, the first regulating transistor Q1 and the second regulating transistor Q2 cannot receive the drive signal, and will not output positive or negative voltages erroneously, thus avoiding unnecessary voltage interference to the power supply module 20 and the focusing mechanism 30. In addition, if the operational amplifier U1 outputs an abnormally high drive signal due to a fault, the conduction threshold of the third regulating transistor Q3 can play a current-limiting protection role. It will only conduct when the signal amplitude is normal and reaches the threshold, preventing abnormal signals from directly impacting the first regulating transistor Q1 and the second regulating transistor Q2, preventing them from being damaged due to overcurrent or overvoltage, and extending the service life of the circuit.

[0051] In the embodiment shown in the accompanying drawings of this invention, the first regulating transistor Q1 is a PNP transistor, with its first terminal being the collector, its second terminal being the base, and its third terminal being the emitter; the second regulating transistor Q2 is an NPN transistor, with its first terminal being the emitter, its second terminal being the base, and its third terminal being the collector; and the third regulating transistor Q3 is an NPN transistor, with its first terminal being the emitter, its second terminal being the base, and its third terminal being the collector.

[0052] Of course, the examples of the types of regulating tubes above are merely illustrative. Based on the understanding of the above embodiments, those skilled in the art should be able to easily change the type of regulating tube. For example, the third regulating tube Q3 may be a PNP type transistor. All such changes should fall within the protection scope of this invention.

[0053] In some embodiments, the voltage regulation circuit 10 may further include a filter protection circuit. Specifically, the filter protection circuit may include a first filter capacitor C5 and a second filter capacitor C6, wherein one end of the first filter capacitor C5 is connected to the forward reference power supply and the other end is grounded, for filtering the forward voltage output by the voltage regulation unit 130. One end of the second filter capacitor C6 is connected to the reverse reference power supply and the other end is grounded, for filtering the reverse voltage output by the voltage regulation unit 130.

[0054] It should be noted that grounding the first filter capacitor C5 and the second filter capacitor C6 refers to connecting them to the floating reference ground, not the ordinary system ground. This is a special design for high-voltage regulation scenarios. In the electron beam scanning device 1, the operating voltage of the focusing mechanism 30 is typically 10kV high voltage, while the ±100V output of the voltage regulation unit 130 is a floating regulation voltage superimposed on this high voltage (i.e., high voltage relative to the system common ground, forming an independent low-voltage regulation loop). The floating reference ground serves as the reference point for this independent regulation loop, avoiding interference or breakdown risks caused by the potential difference between it and the system common ground. It also ensures that the filter capacitors effectively filter the ±100V regulation voltage, rather than affecting the 10kV high voltage.

[0055] Furthermore, the filter protection circuit may also include a first diode D1 and a second diode D3, wherein the first diode D1 is connected in parallel between the first and third terminals of the first regulating transistor Q1 to provide freewheeling protection in the forward voltage regulation path and suppress reverse overvoltage during turn-off. The second diode D3 is connected in parallel between the first and third terminals of the second regulating transistor Q2 to provide freewheeling protection in the reverse voltage regulation path and suppress reverse overvoltage during turn-off.

[0056] Understandably, when the first regulating transistor Q1 is turned off and generates a reverse overvoltage, the first diode D1 is triggered to conduct due to the polarity of the reverse overvoltage, providing a freewheeling path for the residual current in the inductor (the current flows from the output terminal back to the forward reference power supply through the diode), preventing sudden current surges that could lead to high voltage. Simultaneously, the forward voltage drop of the first diode D1 when it is conducting clamps the reverse overvoltage within a safe range, preventing it from impacting the first regulating transistor Q1. Similarly, when the second regulating transistor Q2 is turned off and generates a reverse overvoltage, the second diode D3 conducts, providing a freewheeling path for the residual current in the reverse circuit, clamping the overvoltage within a safe value, and protecting the second regulating transistor Q2 from breakdown.

[0057] In this way, by setting the first diode D1 and the second diode D3, not only can the reverse overvoltage at the moment of turn-off be effectively suppressed, the first regulating tube Q1 and the second regulating tube Q2 be prevented from being damaged by overvoltage and the circuit life be extended, but the interference of overvoltage on the output of the voltage regulating unit 130 can also be reduced, ensuring the smooth switching of the regulating voltage within the preset range, and providing a stable voltage basis for the precise control of the subsequent focusing mechanism 30.

[0058] This invention achieves the aforementioned voltage regulation function through the coordinated operation of specific circuit components, with each core component having a clear and precise function: As a replacement unit for the trigger signal, V5 does not require an additional independent trigger signal source. It can be directly integrated into the circuit to output a suitable initial control signal, providing a stable command source for subsequent adjustments.

[0059] Operational amplifier U1 performs both driving and feedback control functions. It can convert the initial signal output from V5 into a driving signal that meets the operating requirements of the regulating tube, and it can also correct the signal in real time through the feedback circuit to ensure that the output voltage accurately matches the target value.

[0060] Q3 is specifically responsible for the power-on and power-off control of the circuit and safety control. When the device is in standby mode, it is in the off state to avoid accidental triggering of components. During detection, it is only turned on after receiving an allow signal, thus balancing safety and energy efficiency.

[0061] Q1 and Q2 correspond to positive and negative voltage adjustment, respectively. By adjusting their own conduction level, they can precisely control the output amplitude and polarity of ±100V voltage to meet the needs of the focusing mechanism 30 pairs of adapter voltages.

[0062] C5 and C6 are used as filter capacitors to filter high-frequency ripple for ±100V output voltage, ensuring voltage stability.

[0063] D1 and D3 are protection diodes that can effectively suppress reverse overvoltage at the moment the regulating transistor is turned off, preventing component breakdown and damage.

[0064] C4, R2, and R3 form a complete feedback sampling circuit 121, which converts the high voltage into a low voltage signal proportionally and filters out noise, providing a reliable reference for the feedback control of U1.

[0065] In addition, in the circuit on the right side of U1, apart from the resistors and capacitors mentioned above, all other components play a control role, working together to ensure the orderly operation of the circuit.

[0066] Figure 4 yes Figure 3 The continuously adjustable voltage waveform output by the voltage regulation circuit 10 shown is as follows: Figure 4 As shown, based on the optimized design of the aforementioned components, the voltage regulation range covers ±100V, flexibly adapting to the needs of the focusing mechanism 30 for different focusing states. The adjustment speed reaches the 100μs level, a significant improvement compared to traditional high-voltage power supplies, and can match the high-speed image acquisition rhythm of the electron beam scanning equipment 1. The output current is in the mA level, sufficient to drive the power module 20 and the focusing mechanism 30 to operate stably. It also features low noise characteristics, avoiding the impact of voltage fluctuations on the electron beam focusing accuracy, and providing a stable voltage environment for wafer defect detection. Furthermore, the circuit offers good flexibility in component selection. For example, Q3 can be replaced with a PNP transistor depending on the actual application scenario; simply adjusting the polarity of its base drive signal is sufficient for normal operation. R14 can be replaced with a diode, utilizing the unidirectional conductivity of the diode to achieve reverse current limiting, further enhancing the circuit's anti-interference capability against abnormal signals.

[0067] Compared with existing technologies, the core advantage of this invention lies in its pure voltage control architecture: on the one hand, it completely avoids the hysteresis effect commonly found in magnetic field adjustment, and will not cause adjustment errors due to the hysteresis of the magnetic core magnetization, ensuring the consistency of each voltage switch and significantly improving the repeatability and reliability of wafer inspection results; on the other hand, pure voltage control does not require an additional magnetic field generating device, which greatly simplifies the circuit structure, improves the integration, and is more suitable for the layout requirements of high-density inspection stations in semiconductor factories.

[0068] Therefore, those skilled in the art should recognize that although many exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention.

[0069] For example, operational amplifier U1 can be replaced with a differential amplifier with the same function, and regulating transistors Q1 and Q2 can be replaced with MOSFETs, as long as the driving, feedback and regulation logic implemented is consistent with the present invention.

[0070] For example, based on the power requirements of the focusing mechanism 30, the voltage adjustment range is extended to ±200V, and the adjustment speed is optimized to the 50μs level.

[0071] For example, overcurrent protection chips, temperature compensation resistors, and other components can be added to the circuit to improve its stability under extreme conditions.

[0072] These modifications do not alter the core inventive point of this invention: "rapid focusing and regulation achieved through pure voltage control." Therefore, the scope of this invention should not be limited to the specific embodiments disclosed herein, but should fully cover all reasonable variations and technical extensions derived from the principles of this invention, as defined in the claims.

Claims

1. A voltage regulating circuit for providing a set voltage to a power supply module of an electron beam scanning device, characterized in that, The voltage regulating circuit comprises a signal source, a driving control unit and a voltage regulating unit. The signal source is configured to output an initial control signal to the driving control unit. The driving control unit is connected with the signal source and configured to receive the initial control signal and sample the output voltage of the voltage regulating unit to generate a feedback signal, and generate a driving signal by comparing the difference between the initial control signal and the feedback signal. The voltage regulating unit is connected with the driving control unit and configured to receive the driving signal and adjust its working state according to the driving signal to output positive and negative voltages within a preset range which can be continuously adjusted.

2. The voltage regulating circuit according to claim 1, wherein the driving control unit comprises a feedback sampling circuit and an operational amplifier. The feedback sampling circuit is connected with the voltage regulating unit and configured to sample the positive and negative voltages output by the voltage regulating unit to generate a feedback signal and output the feedback signal to the operational amplifier. The operational amplifier is connected with the signal source and the feedback sampling circuit and configured to receive the initial control signal output by the signal source and the feedback signal output by the feedback sampling circuit, generate a corresponding driving signal by comparing the difference between the initial control signal and the feedback signal, and output the driving signal to the voltage regulating unit to regulate the positive and negative voltages output by the voltage regulating unit.

3. The voltage regulating circuit according to claim 2, wherein the feedback sampling circuit comprises a first sampling resistor, a second sampling resistor and a sampling capacitor. One end of the first sampling resistor is connected with the output end of the voltage regulating unit, and the other end is connected with the second sampling resistor, which are used to sample the positive and negative voltages output by the voltage regulating unit in cooperation with the second sampling resistor, and the sampling capacitor is connected in parallel to the two ends of the first sampling resistor, which is used to filter the sampling signal obtained by the sampling to form the feedback signal and output the feedback signal to the operational amplifier.

4. The voltage regulating circuit according to claim 2, wherein the operational amplifier has a non-inverting input end, an inverting input end and a signal output end, the non-inverting input end is connected with the signal source, the inverting input end is connected with the feedback sampling circuit, and the signal output end is connected with the voltage regulating unit.

5. The voltage regulating circuit according to claim 2, wherein the voltage regulating unit comprises a first regulating tube and a second regulating tube. The first end of the first regulating tube is connected with a positive reference power supply, the second end is connected with the operational amplifier, and the third end is connected with the output end of the voltage regulating unit. The first end of the second regulating tube is connected with a negative reference power supply, the second end is connected with the operational amplifier, and the third end is connected with the output end of the voltage regulating unit. ​ ​ ​ ​ ​ The first regulating tube is configured to adjust the output amplitude of the forward reference voltage under the action of the driving signal, and the second regulating tube is configured to adjust the output amplitude of the reverse reference voltage under the action of the driving signal, so that the output end of the voltage regulating unit outputs positive and negative voltages that can be continuously adjusted within a preset range.

6. The voltage regulating circuit according to claim 5, characterized in that, The voltage regulating unit further comprises a third regulating tube; the first end of the third regulating tube is grounded, the second end of the third regulating tube is connected with the operational amplifier, and the third end of the third regulating tube is connected with the second end of the first regulating tube and the second end of the second regulating tube respectively; the third regulating tube is configured to control conduction and cutoff under the joint action of the driving signal and its own conduction threshold, and when the third regulating tube is turned on, the first regulating tube, the second regulating tube and the operational amplifier are turned on to allow the adjusted positive and negative voltage output, and when the driving signal makes the third regulating tube cutoff, the first regulating tube, the second regulating tube and the operational amplifier are disconnected.

7. The voltage regulating circuit according to claim 5, characterized in that, the first regulating tube is a PNP type triode, the first end of which is a collector, the second end is a base, and the third end is an emitter; the second regulating tube is an NPN type triode, the first end of which is an emitter, the second end is a base, and the third end is a collector.

8. The voltage regulation circuit of claim 5, wherein, Further comprising: a filter protection circuit comprising a first filter capacitor and a second filter capacitor; one end of the first filter capacitor is connected with the forward reference power supply, and the other end is grounded, for filtering the forward voltage output by the voltage regulating unit; one end of the second filter capacitor is connected with the reverse reference power supply, and the other end is grounded, for filtering the reverse voltage output by the voltage regulating unit.

9. The voltage regulating circuit according to claim 8, characterized in that, the filter protection circuit further comprises a first diode and a second diode; the first diode is connected in parallel between the first end and the third end of the first regulating tube, for providing freewheeling protection in the adjustment path of the forward voltage to inhibit reverse overvoltage when turned off; the second diode is connected in parallel between the first end and the third end of the second regulating tube, for providing freewheeling protection in the adjustment path of the reverse voltage to inhibit reverse overvoltage when turned off.

10. An electron beam scanning device, characterized by comprising the voltage regulating circuit according to any one of claims 1-9, a power supply module and a focusing mechanism; the power supply module is connected with the focusing mechanism, the voltage regulating circuit is connected with the power supply module, and the voltage regulating circuit is configured to regulate the output voltage of the power supply module by outputting continuously adjustable positive and negative voltages, so that the power supply module outputs an adapted working voltage to the focusing mechanism.

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