Small-size temperature/high-pressure integrated sensor via flip-chip method

Hydraulic technology with smaller sizes and higher reliability trends,including fault prediction and intelligent control,requires high-performance temperature and pressure-integrated sensors.Current designs rely on planar wafer-or chip-level integration,which is limited by pressure range,chip size,and low reliability.We propose a small-size temperature/high-pressure integrated sensor via the flip-chip technique.The pressure and temperature units are arranged vertically,and the sensing signals of the two units are integrated into one plane through silicon vias and gold–gold bonding,reducing the lateral size and improving the efficiency of signal transmission.The flip-chip technique ensures a reliable electrical connection.A square diaphragm with rounded corners is designed and optimised with simulation to sense high pressure based on the piezoresistive effect.The temperature sensing unit with a thin-film platinum resistor measures temperature and provides back-end high-precision compensation,which will improve the precision of the pressure unit.The integrated chip is fabricated by MEMS technology and packaged to fabricate the extremely small integrated sensor.The integrated sensor is characterised,and the pressure sensor exhibits a sensitivity and sensitivity drift of 7.97mV/MPa and−0.19%FS in the range of 0–20 MPa and−40 to 120℃.The linearity,hysteresis,repeatability,accuracy,basic error,and zero-time drift are 0.16%FS,0.04%FS,0.06%FS,0.18%FS,±0.23%FS and 0.04%FS,respectively.The measurement error of the temperature sensor and temperature coefficient of resistance is less than±1°C and 3142.997 ppm/℃,respectively.The integrated sensor has broad applicability in fault diagnosis and safety monitoring of high-end equipment such as automobile detection,industrial equipment,and oil drilling platforms.

Advances in high-performance MEMS pressure sensors:design,fabrication,and packaging

Pressure sensors play a vital role in aerospace,automotive,medical,and consumer electronics.Although microelectromechanical system(MEMS)-based pressure sensors have been widely used for decades,new trends in pressure sensors,including higher sensitivity,higher accuracy,better multifunctionality,smaller chip size,and smaller package size,have recently emerged.The demand for performance upgradation has led to breakthroughs in sensor materials,design,fabrication,and packaging methods,which have emerged frequently in recent decades.This paper reviews common new trends in MEMS pressure sensors,including minute differential pressure sensors(MDPSs),resonant pressure sensors(RPSs),integrated pressure sensors,miniaturized pressure chips,and leadless pressure sensors.To realize an extremely sensitive MDPS with broad application potential,including in medical ventilators and fire residual pressure monitors,the“beam-membrane-island”sensor design exhibits the best performance of 66μV/V/kPa with a natural frequency of 11.3 kHz.In high-accuracy applications,silicon and quartz RPS are analyzed,and both materials show±0.01%FS accuracy with respect to varying temperature coefficient of frequency(TCF)control methods.To improve MEMS sensor integration,different integrated“pressure+x”sensor designs and fabrication methods are compared.In this realm,the intercoupling effect still requires further investigation.Typical fabrication methods for microsized pressure sensor chips are also reviewed.To date,the chip thickness size can be controlled to be<0.1 mm,which is advantageous for implant sensors.Furthermore,a leadless pressure sensor was analyzed,offering an extremely small package size and harsh environmental compatibility.This review is structured as follows.The background of pressure sensors is first presented.Then,an in-depth introduction to MEMS pressure sensors based on different application scenarios is provided.Additionally,their respective characteristics and significant advancements are analyzed and summarized.Finally,development trends of MEMS pressure sensors in different fields are analyzed.