Light intensity detection system of photoetching machine

Abstract

The utility model provides a light intensity detection system of a photoetching machine. The light intensity detection system comprises a light intensity signal acquisition circuit, an ADC conversion circuit, an MCU module and a communication module. The light intensity signal acquisition circuit realizes accurate acquisition and protection of light intensity signals through a voltage division circuit, a differential amplification circuit, a low-pass filter circuit, a voltage follower and a clamping protection circuit. Wherein the voltage division circuit adopts the design of three series resistors, and the middle resistor is a slide rheostat, so that the signal intensity is convenient to adjust and the interference is reduced. The differential amplification circuit performs differential amplification on the signal. The ADC conversion circuit converts an analog signal into a digital signal and transmits the digital signal to the MCU module through an SPI communication protocol. And the MCU module processes and analyzes the digital signal and outputs a result to external equipment or a system through the communication module. The system is suitable for the field of light intensity detection of the photoetching machine, the detection precision of the illumination intensity at a detection point can be remarkably improved, and an important basis is provided for evaluation of illumination uniformity.

Description

Technical Field

[0001] The utility model relates to the technical field of photolithography machines, and in particular to a light intensity detection system for photolithography machines. Background Art

[0002] As the core system of the lithography machine, the exposure system works by emitting light beams through a light source. These light beams are finely adjusted by the mask and the objective lens to accurately project the specific shape of the pattern on the mask onto the wafer. In this process, the light beam is not evenly irradiated, but covers a certain projection area in the form of a light spot. The uniformity of the light intensity of the light spot is crucial to the lithography process, because it directly determines the etching depth of the mask pattern at different positions on the wafer, which in turn affects the overall lithography accuracy of the lithography machine. Therefore, before the wafer lithography process is carried out, accurate detection of the uniformity of the projected light is a necessary step to ensure the quality and accuracy of the lithography.

[0003] In the prior art, the detection of light uniformity usually relies on a light intensity sensor, which is responsible for measuring the light intensity of the projected light spot at different positions. Subsequently, the light uniformity is evaluated by comparing and analyzing the light intensity signals of these different monitoring points. However, if there is a deviation in the light intensity detection accuracy of the light intensity sensor at different detection points within the light spot, it will directly affect the accurate judgment of the light uniformity. Therefore, improving the light intensity detection accuracy of the light intensity sensor at each monitoring point within the projected light spot has become a key issue that needs to be solved urgently. Utility Model Content

[0004] The purpose of the utility model is to provide a light intensity detection system for a photolithography machine, which can significantly improve the detection accuracy of light intensity at a detection point, thereby providing an important basis for judging light uniformity.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A light intensity detection system for a photolithography machine, comprising: a light intensity signal acquisition circuit, an ADC conversion circuit, an MCU module and a communication module;

[0007] The light intensity signal acquisition circuit comprises a voltage divider circuit, a differential amplifier circuit, a low-pass filter circuit, a voltage follower and a clamp protection circuit connected in sequence; wherein, the input end of the voltage divider circuit is provided with three resistors connected in series, and the middle resistor is a sliding rheostat, which is used to adapt the input signal of the light intensity sensor and adjust the signal strength; the differential amplifier circuit receives the voltage at both ends of the sliding rheostat as the input end signal; after the analog signal is initially filtered by the voltage divider circuit, it is transmitted to the differential amplifier circuit for differential amplification, and the differentially amplified signal is filtered by the low-pass filter circuit, and the processed analog signal is stabilized and protected by the voltage follower and the clamp protection circuit, and then transmitted to the input end of the ADC conversion circuit;

[0008] The ADC conversion circuit receives the analog signal output by the light intensity signal acquisition circuit and converts it into a digital signal, and the converted digital signal is transmitted to the MCU module through the SPI communication protocol;

[0009] The MCU module receives the digital signal from the ADC conversion circuit, and after processing and analysis, outputs the processing result to an external device or system through the communication module.

[0010] In a preferred embodiment, the voltage divider circuit includes a capacitor C9, and a resistor R22, a sliding rheostat R20 and a resistor R4 connected in series in sequence; wherein one end of the resistor R22 is used to connect to the light intensity sensor, and the other end is connected to the first fixed contact end of the sliding rheostat R20, the sliding contact end of the sliding rheostat R20 is connected to the second fixed contact end, and is grounded through the resistor R4, and the grounded end of the resistor R4 is also connected to the light intensity sensor to form a closed loop; the capacitor C9 is connected in parallel to both ends of the sliding rheostat R20;

[0011] The differential amplifier circuit includes a first operational amplifier, a resistor R21, a resistor R11, a resistor R25 and a resistor R27; wherein, the same-direction input terminal of the first operational amplifier is divided into two paths, one path is grounded via the resistor R11, and the other path is connected to the connection point between the resistor R22 and the first fixed contact terminal of the sliding rheostat R20 via the resistor R21; the reverse input terminal of the first operational amplifier is divided into two paths, one path is connected to the connection point between the sliding contact terminal of the sliding rheostat R20 and the resistor R4 via the resistor R25, and the other path is fed back to the output terminal of the first operational amplifier via the resistor R27, and the output terminal of the first operational amplifier is connected to the input terminal of the low-pass filter circuit.

[0012] In a preferred embodiment, the low-pass filter circuit includes a resistor R23 and a capacitor C10, the resistor R23 is connected in series to the input end of the low-pass filter circuit, the capacitor C10 is connected in parallel to the output end of the low-pass filter circuit, one end of the resistor R23 is connected to one end of the capacitor C10, and the other end of the capacitor C10 is grounded.

[0013] In a preferred embodiment, the voltage follower includes a second operational amplifier and a resistor R12; wherein the non-inverting input terminal of the second operational amplifier is connected to the output terminal of the low-pass filter circuit, the reverse input terminal of the second operational amplifier is electrically connected to the output terminal of the second operational amplifier via the resistor R12, and the output terminal of the second operational amplifier is electrically connected to the input terminal of the clamping protection circuit.

[0014] In a preferred embodiment, the clamping protection circuit includes a diode D1, a diode D2 and a resistor R24; wherein the cathode of the diode D2 is electrically connected to the power supply, the anode of the diode D2 is electrically connected to the cathode of the diode D1, the anode of the diode D1 is grounded, and the connection point between the diode D1 and the diode D2 is electrically connected to the output end of the voltage follower through the resistor R24.

[0015] In a preferred embodiment, the ADC conversion circuit uses an ADS131 M03IPWR chip.

[0016] In a preferred embodiment, the MCU module includes an STM32 microprocessor of an STM32F103C8T6 chip using a Cortex-M3 architecture and a peripheral configuration circuit.

[0017] In a preferred embodiment, the communication module is an RS485 communication module.

[0018] In a more preferred embodiment, the RS485 communication module uses an isolation chip.

[0019] Furthermore, the RS485 communication module adopts the ADM2582EBRWZ isolation chip.

[0020] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0021] The present application significantly improves the flexibility and adaptability of light intensity signal acquisition by using three series resistors at the light intensity signal input end, especially the design of using a sliding rheostat as the middle resistor. The sliding rheostat can be easily adjusted to adapt to the input signals of different light intensity sensors to ensure the accuracy and stability of the signal.

[0022] The present application adopts three resistors in series for voltage division instead of the traditional two resistors for voltage division, which effectively reduces the interference of AGND (analog ground) on the signal. By optimizing the resistor voltage division structure, the present application can reduce the noise and interference components in the signal, thereby improving the detection accuracy of the light intensity signal.

[0023] The present application can better adapt to the characteristics of the light intensity sensor by adjusting the resistance value of the relevant resistor in the differential amplifier circuit, thereby achieving accurate amplification of the light intensity signal.

[0024] The design of the low-pass filter circuit allows the cut-off frequency to be adjusted according to actual conditions, thereby filtering out high-frequency noise and interference and improving signal quality. In addition, the introduction of the voltage follower and clamp protection circuit can effectively protect the ADC chip, avoiding the risk of signals exceeding the acquisition range and data distortion. At the same time, they can also improve the transmission efficiency and stability of the signal, ensuring that the light intensity signal can be accurately and reliably transmitted to the subsequent processing circuit.

[0025] This application also adopts RS485 communication protocol and is equipped with an isolation chip to ensure the stability and anti-interference ability of system communication and reduce the system's sensitivity to external interference.

[0026] In summary, the application ensures the stable acquisition of light intensity signals and effectively suppresses noise interference through the reasonable configuration and connection of the voltage divider circuit, differential amplifier circuit, low-pass filter circuit, voltage follower and clamp protection circuit. The detection system can significantly improve the detection accuracy of light intensity at the detection point, thereby providing an important basis for the evaluation of light uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0028] Figure 1 It is a modular schematic diagram of a light intensity detection system for a lithography machine provided in an embodiment of the utility model.

[0029] Figure 2 It is a circuit diagram of a light intensity signal acquisition circuit provided in an embodiment of the utility model.

[0030] Figure 3 It is a circuit diagram of an ADC conversion circuit provided by an embodiment of the utility model.

[0031] Figure 4 It is a circuit diagram of the MCU module provided in an embodiment of the utility model.

[0032] Figure 5 It is a circuit diagram of the RS485 communication module provided by the embodiment of the utility model. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and effect of the utility model clearer and more specific, the utility model is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a system, product or device containing a series of units is not necessarily limited to those units clearly listed, but may include other units that are not clearly listed or inherent to these products or devices.

[0035] The present embodiment provides a light intensity detection system for a photolithography machine, which is mainly used to accurately detect the light intensity uniformity in a light spot area at a wafer support table (wafer stage) to ensure the stability and accuracy of the photolithography process.

[0036] like Figure 1 As shown in the figure, this system is mainly composed of a light intensity signal acquisition circuit, an ADC conversion circuit, an MCU module, and a communication module. When the light beam is projected onto the wafer support table through the optical channel, the light intensity signal acquisition circuit is responsible for capturing the light intensity signal in the spot area. After a series of circuit processing, the analog signal is converted into a digital signal and passed to the MCU module for further analysis and calculation. Finally, the processing results are output to an external device or system through the communication module for use by the user or control system.

[0037] For the circuit design of this system, please refer to Figure 2-Figure 5 shown.

[0038] Specifically, the light intensity signal acquisition circuit includes a voltage divider circuit, a differential amplifier circuit, a low-pass filter circuit, a voltage follower and a clamp protection circuit connected in sequence; wherein, the input end of the voltage divider circuit is provided with three resistors connected in series, and the middle resistor is a sliding rheostat, which is used to adapt the input signal of the light intensity sensor and adjust the signal strength; the differential amplifier circuit receives the voltage across the sliding rheostat as the input signal; the analog signal is amplitude adjusted by the voltage divider circuit and then transmitted to the differential amplifier circuit for differential amplification, the differentially amplified signal is filtered by the low-pass filter circuit, and the processed analog signal is stabilized and protected by the voltage follower and the clamp protection circuit before being transmitted to the input end of the ADC conversion circuit.

[0039] The ADC conversion circuit receives the analog signal output by the light intensity signal acquisition circuit and converts it into a digital signal. The converted digital signal is transmitted to the MCU module via the SPI communication protocol.

[0040] The MCU module receives the digital signal from the ADC conversion circuit, and after processing and analysis, outputs the processing result to an external device or system through the communication module.

[0041] Figure 2 The schematic diagram of the structure of the light intensity signal acquisition circuit in this embodiment is shown.

[0042] like Figure 2 As shown, the voltage divider circuit includes a capacitor C9, and a resistor R22, a sliding rheostat R20 and a resistor R4 connected in series in sequence; wherein, one end of the resistor R22 is used to connect to the light intensity sensor, and the other end is connected to the first fixed contact end of the sliding rheostat R20, the sliding contact end of the sliding rheostat R20 is connected to the second fixed contact end, and is grounded through the resistor R4, and the grounded end of the resistor R4 is also connected to the light intensity sensor to form a closed loop; the capacitor C9 is connected in parallel to the two ends of the sliding rheostat R20.

[0043] In this embodiment, the light intensity signal input end uses three resistors in series, with a sliding rheostat in the middle, to adapt the input signal of the light intensity sensor. This design has two major advantages: first, the sliding rheostat is easy to adjust and can be flexibly adjusted according to different light intensity sensors or working environments to ensure the accuracy of signal input; second, the use of three resistors in series to divide the voltage instead of the traditional two resistors in series to divide the voltage effectively reduces the interference of AGND (analog ground) on the signal, thereby improving the detection accuracy.

[0044] The differential amplifier circuit includes a first operational amplifier, a resistor R21, a resistor R11, a resistor R25 and a resistor R27; wherein, the same-direction input terminal of the first operational amplifier is divided into two paths, one path is grounded via the resistor R11, and the other path is connected to the connection point between the resistor R22 and the first fixed contact terminal of the sliding rheostat R20 via the resistor R21; the reverse input terminal of the first operational amplifier is divided into two paths, one path is connected to the connection point between the sliding contact terminal of the sliding rheostat R20 and the resistor R4 via the resistor R25, and the other path is fed back to the output terminal of the first operational amplifier via the resistor R27, and the output terminal of the first operational amplifier is connected to the input terminal of the low-pass filter circuit.

[0045] In this embodiment, the differential amplifier circuit can achieve differential amplification of the input signal by accurately configuring the resistance values ​​of resistors R11, R21, R25 and R27, highlighting the useful information in the signal while suppressing common mode noise. This design enables the differential amplifier circuit to better adapt to different light intensity sensors, improving the versatility and reliability of the system.

[0046] The low-pass filter circuit includes a resistor R23 and a capacitor C10, wherein the resistor R23 is connected in series to the input end of the low-pass filter circuit, and the capacitor C10 is connected in parallel to the output end of the low-pass filter circuit, and one end of the resistor R23 is connected to one end of the capacitor C10, and the other end of the capacitor C10 is grounded. In the present embodiment, the low-pass filter composed of R23 and C10 further performs filtering on the signal after differential amplification. The function of the low-pass filter is to allow low-frequency signals to pass through and suppress high-frequency noise. By flexibly adjusting the values ​​of R23 and C10, the cut-off frequency of the filter can be changed to adapt to different working environments and signal characteristics, thereby improving signal quality.

[0047] The voltage follower is used as a buffer stage or an isolation stage to increase the input impedance and reduce the output impedance. In this embodiment, the voltage follower includes a second operational amplifier and a resistor R12. The specific connection method is: the same-direction input terminal of the second operational amplifier is connected to the output terminal of the low-pass filter circuit, the reverse input terminal of the second operational amplifier is electrically connected to the output terminal of the second operational amplifier through the resistor R12, and the output terminal of the second operational amplifier is electrically connected to the input terminal of the clamp protection circuit.

[0048] The clamping protection circuit plays a limiting protection role on the input voltage signal to prevent the signal from exceeding the acquisition limit value of the ADC chip, thereby ensuring the safety and stable operation of the ADC chip. In this embodiment, the clamping protection circuit includes a diode D1, a diode D2 and a resistor R24. The specific connection method is: the cathode of the diode D2 is electrically connected to the 3.3V power supply, the anode of the diode D2 is electrically connected to the cathode of the diode D1, the anode of the diode D1 is grounded, the output end of the second operational amplifier is electrically connected to the anode of the diode D2 through the resistor R24, and the anode of the diode D2 is also electrically connected to the input end of the ADC conversion circuit.

[0049] Figure 3 FIG. 2 shows a schematic diagram of the ADC conversion circuit in this embodiment. Figure 3 As shown, in a preferred embodiment, the ADC conversion circuit uses an ADS131 M03IPWR chip. When the analog signal is input to the ADS131 M03IPWR chip, the chip converts the collected analog signal into a digital signal, and then transmits the converted digital signal to the MCU module through the SPI communication protocol.

[0050] Figure 4 FIG. 1 shows a circuit diagram of the MCU module in this embodiment. Figure 4 As shown, the MCU module includes an STM32 microprocessor of an STM32F103C8T6 chip using a Cortex-M3 architecture and a peripheral configuration circuit.

[0051] Figure 5 FIG. 1 shows a circuit diagram of the communication module in this embodiment. Figure 5 As shown, the communication module adopts an RS485 communication module, so that the data processed by the MCU module can be smoothly output through the RS485 serial communication circuit. In order to further improve the reliability of signal transmission, this embodiment also preferably adopts an isolation chip, such as the ADM2582EBRWZ isolation chip, to effectively reduce signal interference and ensure the stability and accuracy of data transmission.

[0052] In summary, the utility model provides a light intensity detection system for a photolithography machine, which is composed of a light intensity signal acquisition circuit, an ADC conversion circuit, an MCU module and a communication module, and is intended to achieve accurate detection of the uniformity of light intensity in the light spot area at the wafer support table. The three-resistor R4 series design in the light intensity signal acquisition circuit effectively reduces the interference of AGND on the signal and improves the detection accuracy; the differential amplifier circuit achieves adaptation to different light intensity sensors by accurately configuring the resistance value, thereby improving the versatility and reliability of the system. The ADC conversion circuit uses the ADS131 M03IPWR chip to convert the analog signal into a digital signal and transmit it to the MCU module through the SPI communication protocol. The MCU module is based on the STM32F103C8T6 chip based on the Cortex-M3 architecture, which realizes the processing and analysis of data. Finally, the communication module uses the RS485 communication module, combined with the use of the isolation chip, to ensure the stability and accuracy of data transmission.

[0053] The light intensity detection system of the lithography machine of the utility model realizes the accurate detection of light intensity uniformity by optimizing the circuit design and adopting advanced technology, which provides strong support for the stability and accuracy of the lithography process. The system has the advantages of strong versatility, high reliability and high precision, and can be widely used in the field of light intensity detection of lithography machines, providing important guarantee for improving product quality and process efficiency.

[0054] The specific embodiments of the utility model are described in detail above, but they are only examples, and the utility model is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modification and substitution of the utility model is also within the scope of the utility model. Therefore, the equalization transformation and modification made without departing from the spirit and scope of the utility model should be included in the scope of the utility model.

Claims

1. A light intensity detection system for a photolithography machine, characterized in that: include: Light intensity signal acquisition circuit, ADC conversion circuit, MCU module and communication module; The light intensity signal acquisition circuit comprises a voltage divider circuit, a differential amplifier circuit, a low-pass filter circuit, a voltage follower and a clamp protection circuit connected in sequence; wherein, the input end of the voltage divider circuit is provided with three resistors connected in series, and the middle resistor is a sliding rheostat, which is used to adapt the input signal of the light intensity sensor and adjust the signal strength; the differential amplifier circuit receives the voltage at both ends of the sliding rheostat as the input end signal; the analog signal is processed by the voltage divider circuit amplitude adjustment, and then transmitted to the differential amplifier circuit for differential amplification, the differentially amplified signal is filtered by the low-pass filter circuit, and the processed analog signal is stabilized and protected by the voltage follower and the clamp protection circuit, and then transmitted to the input end of the ADC conversion circuit; The ADC conversion circuit receives the analog signal output by the light intensity signal acquisition circuit and converts it into a digital signal. The converted digital signal is transmitted to the MCU module via the SPI communication protocol; The MCU module receives the digital signal from the ADC conversion circuit, and after processing and analysis, outputs the processing result to an external device or system through the communication module.

2. A light intensity detection system for a lithography machine according to claim 1, characterized in that: The voltage divider circuit includes a capacitor C9, and a resistor R22, a sliding rheostat R20 and a resistor R4 connected in series in sequence; wherein one end of the resistor R22 is used to connect to the light intensity sensor, and the other end is connected to the first fixed contact end of the sliding rheostat R20, the sliding contact end of the sliding rheostat R20 is connected to the second fixed contact end, and is grounded through the resistor R4, and the grounded end of the resistor R4 is also connected to the light intensity sensor to form a closed loop; the capacitor C9 is connected in parallel to both ends of the sliding rheostat R20; The differential amplifier circuit includes a first operational amplifier, a resistor R21, a resistor R11, a resistor R25 and a resistor R27; wherein, the same-direction input terminal of the first operational amplifier is divided into two paths, one path is grounded via the resistor R11, and the other path is connected to the connection point between the resistor R22 and the first fixed contact terminal of the sliding rheostat R20 via the resistor R21; the reverse input terminal of the first operational amplifier is divided into two paths, one path is connected to the connection point between the sliding contact terminal of the sliding rheostat R20 and the resistor R4 via the resistor R25, and the other path is fed back to the output terminal of the first operational amplifier via the resistor R27, and the output terminal of the first operational amplifier is connected to the input terminal of the low-pass filter circuit.

3. The light intensity detection system for a lithography machine according to claim 1, characterized in that: The low-pass filter circuit includes a resistor R23 and a capacitor C10, the resistor R23 is connected in series to the input end of the low-pass filter circuit, the capacitor C10 is connected in parallel to the output end of the low-pass filter circuit, one end of the resistor R23 is connected to one end of the capacitor C10, and the other end of the capacitor C10 is grounded.

4. The light intensity detection system for a lithography machine according to claim 1, characterized in that: The voltage follower includes a second operational amplifier and a resistor R12; wherein the non-inverting input terminal of the second operational amplifier is connected to the output terminal of the low-pass filter circuit, the reverse input terminal of the second operational amplifier is electrically connected to the output terminal of the second operational amplifier via the resistor R12, and the output terminal of the second operational amplifier is electrically connected to the input terminal of the clamp protection circuit.

5. The light intensity detection system for a lithography machine according to claim 1, characterized in that: The clamping protection circuit includes a diode D1, a diode D2 and a resistor R24; wherein the cathode of the diode D2 is electrically connected to the power supply, the anode of the diode D2 is electrically connected to the cathode of the diode D1, the anode of the diode D1 is grounded, and the connection point between the diode D1 and the diode D2 is electrically connected to the output end of the voltage follower through the resistor R24.

6. The light intensity detection system for a lithography machine according to claim 1, characterized in that: The ADC conversion circuit adopts the ADS131 M03IPWR chip.

7. The light intensity detection system for a lithography machine according to claim 1, characterized in that: The MCU module includes an STM32 microprocessor of an STM32F103C8T6 chip with a Cortex-M3 architecture and a peripheral configuration circuit.

8. The light intensity detection system for a lithography machine according to claim 1, characterized in that: The communication module is an RS485 communication module.

9. A light intensity detection system for a lithography machine according to claim 8, characterized in that: The RS485 communication module adopts an isolation chip.

10. A light intensity detection system for a lithography machine according to claim 9, characterized in that: The RS485 communication module adopts the ADM2582EBRWZ isolation chip.

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