计量科学与技术

2023, 67(2): 1-2.

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Online Calibration of CD-SEM Magnification Based on Nanolattice Pitch Wafer Standard

JIN Hongxia, RAO Zhangfei, QIN Kailiang

2023, 67(2): 29-35. doi: 10.12338/j.issn.2096-9015.2022.0294

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In semiconductor manufacturing, the critical dimension scanning electron microscope (CD-SEM) is a high-precision device used for the online measurement of chip feature size. The measurement results directly affect the evaluation of device electrical performance parameters and the judgment of circuit product reliability. However, there is still a lack of special measuring standards and calibration specifications for evaluating the measurement characteristics of CD-SEM. As a result, most calibrators refer to the JJF 1916-2021 Calibration Specification for Scanning Electron Microscopes (SEM) for online measurement of length indication errors in practice. The essence of using the nanolattice pitch standard to calibrate the CD-SEM magnification is to observe the measured image and obtain the pitch result by setting various instrument parameters and multiple pitches under different magnification conditions. Subsequently, the measured pitch result is compared to the certificate value of the standard to determine whether the instrument status is normal and whether the measurement accuracy meets process requirements. In this paper, we discuss an online calibration method of CD-SEM magnification based on the 100 nm nanolattice pitch wafer standard and introduce the measurement principle. We then describe the uncertainty analysis and conformity decision method of results under specific magnification with specific examples. Additionally, we briefly introduce three problems of the calibration process, such as the deterioration of the wafer standard, the noise of the measuring instrument, and contamination caused by an improper operational program. Finally, we summarize corresponding solutions, which have some reference value for future research on the online calibration of integrated circuit nano-parameters measurement equipment.

Strategy of International Committee for Weights and Measures on Climate Change and Environment

BI Zhe, SONG Xiaoping, CHAO Jingbo, LIN Hong, DAI Caihong, HAO Xiaopeng, HE Longbiao, LIU Haoran

2023, 67(2): 3-12. doi: 10.12338/j.issn.2096-9015.2022.0253

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Climate change and environmental issues are highly relevant to the Sustainable Development Goals (SDGs) of the United Nations. Measuring Essential Climate Variables (ECVs) and studying the synergistic toxic effects of environmental pollutants pose significant challenges for metrology science. To address these challenges, the International Committee for Weights and Measures (CIPM) has developed the CIPM Strategy 2030+ and action plans for strengthening basic metrology research and interdisciplinary collaboration to enhance the support of metrology science in policy decisions. The European Association of National Metrology Institutes (EURAMET) has carried out a series of studies focusing on environmental and climate monitoring to meet the regulatory needs of the European Union. The EURAMET members actively participate in the World Meteorological Organization (WMO) network, providing valuable references for metrology science development in China. To support the implementation of "Synergy between pollution and carbon emission control" in China, metrology research efforts should focus on measuring emerging pollutants and developing online calibration methods. The measurement of carbon emissions and other pollutants should also be improved. Overall, the metrology standards, natural matrix reference materials, critical components of environmental instruments, and fundamental metrology methodology need to be enhanced to support national climate and environmental strategies. To achieve these goals, metrology institutions at all levels should work together to strengthen departmental cooperation and establish scientific resource-sharing mechanisms. In addition, metrology institutions should strengthen cooperation with related domestic and international agencies and institutes to improve the quality of crucial data and advisory capacity for decision-making.

Metrological Challenges and Prospects in the Field of Life Sciences

LIU Yahui, ZHAO Yang, XUE Zhichao, NIU Chunyan, LIU Yingying, DONG Lianhua

2023, 67(2): 13-17. doi: 10.12338/j.issn.2096-9015.2023.0008

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The global outbreak of COVID-19 has brought healthcare and the life science industry into the spotlight, raising people's attention to disease prevention, treatment, research and development of biological drugs, in vitro diagnosis, and internet medicine. Metrology technology plays a critical role in supporting these fields. The study of metrology technology in life sciences is an essential component of serving public health and a solid foundation for promoting the development of the health and life sciences industry. This paper explores the development ideas of metrology science to support life sciences through literature research, case studies, and the analysis of the strategic reports of domestic and international metrology institutions. Based on this analysis, we propose some suggestions for developing biological metrology in China.

Research on Measurement Method of BeiDou RDSS Inbound Receiver

ZHANG Jing, YANG Zhiqiang, LIANG Guihai

2023, 67(2): 18-23, 35. doi: 10.12338/j.issn.2096-9015.2022.0259

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BeiDou Satellite Navigation System (BDS) application is spreading worldwide. With the comprehensive promotion of BDS, the measurement of BDS terminals (receivers) is becoming increasingly important. Mastering scientific and accurate measurement methods is a top priority for the quality assurance of BeiDou receivers. This paper proposes a measurement method of corresponding parameters based on the measurement characteristics of the BeiDou Radio Determination Satellite Service (RDSS) incoming receiver. The measurement experiments of frequency, power, carrier suppression error, phase modulation error and bidirectional delay of the RDSS inbound receiver were conducted. The experimental results showed that the measured RDSS inbound receiver has typical measurement characteristics. The correctness and rationality of the measurement method were also verified.

Research on Calibration Method of Automatic Measuring Instrument for Automobile Tyre Tread Depth

ZHANG Hongbao, ZHENG Xiaoxiao, JIANG Kun

2023, 67(2): 24-28. doi: 10.12338/j.issn.2096-9015.2023.0006

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To ensure the uniformity, accuracy, and reliability of automatic measuring instruments for motor vehicle tyre tread depth, a calibration method is proposed. Firstly, the calibration status both domestically and internationally is introduced, followed by describing the measuring principle for tyre tread depth. The technical scheme of the calibration device is then proposed, and the technical indicators and traceability methods of the calibration device are demonstrated. In addition, through analysis and experimental research on the calibration method, the test results show that the measuring instrument indication error meets MPE: ±0.10 mm, and the calibration method is reasonable and operable. An uncertainty evaluation reveals U = 0.03 mm (k = 2). Finally, a comparison test and data analysis show that the maximum difference modulus of the measured value of the tread depth indication error meets verification requirements, thus verifying the calibration method.

Design of a Miniature Ultra-Wideband Antenna with Low Cross Polarization

WEI Jihu, MENG Donglin, SONG Xiaoqian

2023, 67(2): 36-41, 74. doi: 10.12338/j.issn.2096-9015.2023.0068

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In applications such as precise near field antenna measurements and plane wave generator, the operating frequency is often limited by the bandwidth of the near-field scanning probe. To overcome the bandwidth limitation of open-ended waveguide probes, Ultra-Wideband (UWB) small aperture antennas based on Vivaldi antennas have been developed. However, their cross polarization performance is poor due to their common asymmetric structure. To address this issue, a miniature UWB antenna with low cross polarization is proposed in this paper. A 5-layer symmetrical structure is used to improve the traditional asymmetric Vivaldi antenna, and a Bezier curve is employed to design the gradient slot radiation structure. Loading resistance, patch, and etching rectangular chutes are also used to reduce the antenna standing wave and improve radiation directivity. The proposed antenna has an aperture width of 70 mm and a length of 201 mm. In the 0.9-6 GHz frequency band, the simulated cross polarization ratio of the antenna is better than 40.9 dB, and the gain is between −5.5 dBi to 9.53 dBi. The port reflection coefficient amplitude is less than −10 dB, and the radiation pattern is smooth, symmetrical, and without pits across the entire frequency bandwidth.

Establishment of Verification Device for Natural Gas Flow Integration Meters

JIANG Chen

2023, 67(2): 42-47. doi: 10.12338/j.issn.2096-9015.2022.0308

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The natural gas flow integration meter is a secondary instrument used for natural gas metering. Its function is to process and calculate the signals transmitted from primary instruments on site, such as temperature transmitters, pressure transmitters, gas chromatographs, flowmeters, etc., and finally calculate the natural gas flow or energy under standard conditions. In order to ensure the accuracy and consistency of the measurement results of the measuring instruments and maintain the economic interests of both the supplier and the demander, it is necessary to carry out the verification and calibration of the flow integration meters. According to JJF 1003-2016 Flow Integration Meters, a set of verification devices for natural gas flow integration meters has been established. The device is composed of three multi-functional calibrators, which output the corresponding standard signals of the temperature transmitter, pressure transmitter, and flowmeter to the flow integration meter. After receiving the standard signals, the flow integration meter converts them into the target values, and the measurement errors of each channel are calculated according to JJG 1003-2016. Through the repeatability experiment of temperature, pressure, and flow channels, the uncertainty of the measurement results has been evaluated. The expanded uncertainty of the verification device is 0.14%, which can be used to verify and calibrate flow integration meters with accuracy class 0.5 and below. The standard device has passed the measurement standard assessment organized by State Administration for Market Regulation and solved the problem of tracing the value of the flow integration meter at the natural gas station. Based on the verification device, the matters needing attention and problems in the verification process of the flow integration meters are discussed, and suggestions for the revision of the verification regulations are put forward.

An Improved Automatic Calibration Equipment for Non-Contact Electrostatic Voltmeter

WANG Yuesheng, LIAO Wei, ZHU Yujie

2023, 67(2): 48-52. doi: 10.12338/j.issn.2096-9015.2022.0119

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Non-contact electrostatic voltmeters, also known as explosion-proof electrostatic voltmeters, are important instruments for preventing electrostatic hazards. The accuracy and reliability of their measurements are of great importance. However, the current automatic calibration process suffers from significant measurement uncertainties. In accordance with the JJG 192—2019 "Verification Regulation for Non-contact Electrostatic Voltmeter," this paper analyzes the causes of uncertainty in the automatic calibration process of non-contact electrostatic voltmeters. Based on this analysis, an improved automatic calibration equipment for remote programmable calibration of non-contact electrostatic voltmeters has been developed. The equipment includes remote programmable distance adjustment and zero out, electromagnetic interference shielding, and automatic grounding equipment, which ensure complete isolation between the operator and the high-voltage sources. The actual measurement results show that the improved equipment reduces the systematic measurement uncertainty of 10% to 50% of the traditional method to 0.3%, meeting the calibration requirements of non-contact electrostatic voltmeters.

Design of a Remote Anti-Cheating System for Fuel Dispensers

YAO Suna, LI Nini, ZHENG Qun, LI Chaoqi

2023, 67(2): 53-57, 12. doi: 10.12338/j.issn.2096-9015.2022.0296

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Cheating problems in fuel dispensers have been a persistent issue for consumers, market supervision, and tax control departments. While many research results have been achieved in preventing cheating, illegal individuals still find new ways to cheat. To further address metering cheating in fuel dispensers, this paper proposes a design method for a remote anti-cheating system that can monitor real-time metering and cumulative operation status. An independently running computer pulse counting device is attached to the fuel dispenser computer motherboard. The wireless data acquisition module uploads the fuel dispenser pulse count, fuel volume, and cumulative volume from the fuel dispenser tax controller's RS232 communication interface to the server. The fuel dispenser pulse equivalent parameters stored on the server side are periodically compared with the fuel dispenser motherboard data. The fuel dispenser is automatically locked if the comparison result exceeds the limit. This system enables market supervision and tax control departments to monitor all data and operation status in real-time remotely. Practical application has shown that the system has low investment cost and strong operability, and can fundamentally monitor cheating behavior in fuel dispensers, preventing metering cheating.

Calibration: Interpretation of Definition and Expression of Measurement Uncertainty

WANG Weinong

2023, 67(2): 58-61. doi: 10.12338/j.issn.2096-9015.2022.0225

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Differences between the existing definition of calibration and the activities of calibration laboratories have led to problems in the expression of calibration results, the measurement uncertainty of calibration results, calibration and measurement capability (CMC), and the expression of measurement uncertainty in calibration certificates. These issues result in incorrect expression of calibration results or failure to achieve desired outcomes in the application. Using examples, this paper illustrates the negative effects of these problems on the metrological confirmation, examination of measurement standards, and laboratory's CMC. Based on the definition of calibration, this paper discusses evaluation methods of calibration results and measurement uncertainty, and proposes suggestions for expressing calibration and measurement capabilities, results, and measurement uncertainty in calibration certificates.

Balance Optimization of Inertia Force of Jaw Crusher

HE Renwei, LV Dong, HUANG Yuxing, XUE Pu

2023, 67(2): 62-67. doi: 10.12338/j.issn.2096-9015.2022.0312

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Due to the particularity of its working nature, jaw crushers produce a lot of noise and vibration, which can cause fatigue damage to key machine components, reduce the structural characteristics and working stability of the whole machine, and indirectly affect the daily working environment and efficiency. Severe vibration can even cause irreparable damage to the device itself, thus reducing its service life. Vibration is a crucial factor affecting the regular operation of instruments and equipment, and intense vibration significantly affects the speed calibration accuracy of the crusher. Therefore, to reduce the jaw crusher's vibration frequency, this paper uses system modeling and C++ programming to analyze the vibration sources of the mechanical system, apply relevant knowledge of mechanical system dynamics to analyze the system's inertia force, and optimize the crusher's structure. By changing the eccentric counterweight and counterweight angle of the crusher flywheel, the centroid of the eccentric shaft, flywheel, and large pulley can meet the motion equation of the centroid of the jaw crusher's moving components. Experimental results show that this method can reduce the inertia force of the system to two-thirds of its original value.

Research on the Influence of Butterfly Valve on the Onine Calibration Performance of Ultrasonic Flowmeter

GENG Cunjie, ZHANG Dongfei, LI Guozhan, ZHANG Hongjun

2023, 67(2): 68-74. doi: 10.12338/j.issn.2096-9015.2022.0048

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In order to reduce the interference of flow obstructions on ultrasonic flowmeter online calibration, a large eddy simulation is performed on the flow field in the ultrasonic flowmeter downstream of the butterfly valve. The effects of the opening degree of the butterfly valve, the flow direction, and the circumferential installation position on the velocity distribution on the sound channel are analyzed. The results indicate that the butterfly valve causes severe distortion of the velocity distribution in the downstream pipe. With the increase of the ultrasonic flowmeter flow direction installation distance, the interference effect of the flow pattern distortion gradually weakens. The sensitivity of the correction coefficient to the circumferential installation angle also gradually decreases, and the maximum difference decreases from 0.12 to 0.04. The circumferential installation position of the ultrasonic flowmeter has a significant impact on the velocity distribution on its sound channel, resulting in fluctuations in the correction coefficient with the change of the circumferential installation angle. Furthermore, the farther away from the butterfly valve, the smaller the fluctuation value of the correction coefficient, especially when the circumferential installation angle is 0° and 180°, and the error of the correction coefficient is less than 0.04. The degree of flow pattern distortion in the pipe decreases with the increase of the butterfly valve opening, which improves the uniformity of the velocity distribution on the sound channel of the ultrasonic flowmeter. The recommended installation position of the ultrasonic flowmeter under the condition of butterfly valve disturbance is obtained, which is helpful in improving the accuracy of the online calibration.

2023 Vol. 67, No. 2

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