CN1272612C - High temperature pressure sensor workable in high range, high over loading - Google Patents

Abstract

The present invention discloses a pressure sensor workable in a high range, high over loading and high temperature, which comprises a casing which is characterized in that the casing is provided with external screws, and the inside of the casing is provided with a cavity; one end of the casing is provided with a wire outlet cap, and the other end of the casing is orderly provided with a high temperature switching circuit board, an overload protection block and an elastic element; the elastic element is provided with a micro-solid compressive resistance chip of SOI silicon, and the lead-out wire of the micro-solid compressive resistance chip of SOI silicon is connected with the high temperature switching circuit board by a gold-wire outlet hole on the overload protection block; the high temperature switching board leads out a high temperature-resistance cable wire to penetrate through the casing, and the high temperature-resistance cable wire is fastened by the wire outlet cap. The present invention can be used for measuring pressure in harsh environment, for example, the temperature is larger than or equal to 150 DEG, the pressure is from 100MPa to 1000MPa, the overload is high (more than 30 times of full range), the high frequency is sonorous, etc. The present invention having the advantages of high precision, good reliability, etc. can be widely used for measuring pressure in the fields, such as military industries, petrochemical industries, etc.

Description

High temperature pressure sensor workable in high range, high over loading

Technical field

The invention belongs to micromechanics electronic system (MEMS) technology and integrated circuit micro-processing technology field, be specifically related to a kind of high temperature pressure sensor workable in high range, high over loading.

Background technology

At present, calibration device for high range pressure transducer generally adopts the piezoelectric type structural principle, and the output signal of piezoelectric pressure indicator is the charge variation amount, and therefore follow-up signal processing circuit is more loaded down with trivial details.Piezoelectric pressure indicator is not suitable for using under hot environment, and does not have the ability of high overload protection.Adopt the calibration device for high range pressure transducer of metal strain plate as sensitive element, the disadvantage that this kind sensor exists is exactly that output signal is too little, and under hot environment, temperature is bigger to the deformation effect of metal strain plate, influence the output of sensor, be not suitable for hot environment.In addition, though other are used for the copper-manganese sensor of impact wave measurement or the range of ytterbium sensor can reach more than the 100GPa, do not reach reusable purpose all in the microsecond level its serviceable life, uses inconvenience, is not suitable for hot environment yet.

Summary of the invention

The objective of the invention is to; a kind of high temperature pressure sensor workable in high range, high over loading is provided; flat film elasticity element and the little solid-state sculptured chips incorporate of SOI (silicon isolation) silicon that this sensor adopts unstressed encapsulation technologies such as eutectic welding or glass dust sintering will have overcurrent protection structure are the elasticity sensing unit of one as sensor; measure the difficult problem of high overload, wide range pressure to solve under the hot environment, and have the high frequency sound characteristic.

To achieve these goals; the technical scheme that the present invention takes is; a kind of high temperature pressure sensor workable in high range, high over loading; comprise a shell; it is characterized in that; this shell has external thread and inside is provided with cavity; end at shell has the outlet cap; the cavity end of shell is provided with the high temperature switching circuit board successively; overload protection block and flexible member; the little solid-state sculptured chip of SOI silicon is arranged on the flexible member; adopt ultrasonic bonding equipment to draw Herba Anoectochili roxburghii from the little solid-state sculptured chip of SOI silicon; and be connected with the high temperature switching circuit board by the gold wire lead-out hole on the overload protection block; the high temperature card extender is drawn the Pyrotenax line and passed shell, and is by the outlet cap that the Pyrotenax line is fastening.

This sensor has the overload protection ability, can transship full scale more than 30 times, and can bear certain TRANSIENT HIGH TEMPERATURE and impact.Such sensor has dynamic perfromance good, high temperature resistant (〉=150 ℃), high range (〉=characteristics such as 100MPa), work safety, reliable under rugged surroundings such as high temperature, high pressure, solve the pressure survey difficult problem under hot conditions and the high pressure occasion, and had the high overload ability more than 30.

Description of drawings

Fig. 1 is a structure principle chart of the present invention.

Fig. 2 is the micro-photograph of the little solid-state sculptured chip of SOI silicon.

Fig. 3 is an elasticity sensing unit structural drawing of the present invention.

Fig. 4 is the overload protection block structural diagram.

Below in conjunction with accompanying drawing and principle of work the present invention is further detailed.

Embodiment

High temperature pressure sensor workable in high range, high over loading basic structure of the present invention is seen Fig. 1; comprise a shell 5; this shell 5 has external thread and inside is provided with cavity; end at shell 5 has outlet cap 6; the cavity end of shell 5 is provided with high temperature switching circuit board 4 successively; overload protection block 3 and flexible member 2; the little solid-state sculptured chip 1 of SOI silicon is arranged on the flexible member 2; the extension line of the little solid-state sculptured chip 1 of SOI silicon is connected with high temperature switching circuit board 4 by the gold wire lead-out hole on the overload protection block 3; high temperature card extender 4 is drawn the Pyrotenax line and passed shell 5, and is by outlet cap 6 that the Pyrotenax line is fastening.

The little solid-state sculptured chip 1 of domain SOI silicon as shown in Figure 2 is encapsulated in the stress raiser of flexible member 2 by eutectic bonding or glass dust sintering process, as shown in Figure 3, eliminate technology by a series of unrelieved stress again, eliminate the influence of encapsulation stress sensor performance; Earlier flexible member 2 and overload protection block 3 are combined as a whole by laser welding process, and then with shell 5 laser bonding, overload protection block 3 as shown in Figure 4 can make sensor have overload capacity more than 30 times; Draw Herba Anoectochili roxburghii by gold wire bonder or excess sound pressure welding machine etc. from the little solid-state sculptured chip 1 of SOI silicon, link by gold wire lead-out hole on the overload protection block 3 and high temperature switching circuit board 4, draw the Pyrotenax line from high temperature card extender 4, and by shell 5 and outlet cap 6 that the cable clue is tight; By being threaded on the shell 5 this invention is installed in the pressure of measuring fluid on the pipeline at last.

Sensitive element of the present invention is the little solid-state sculptured chip of SOI silicon that adopts SIMOX (energetic oxygen ions injections) fabrication techniques in MEMS technology and the SOI technology, has solved chip that conventional pn knot isolates generation leakage current and influence the problem of sensor performance under greater than 120 ℃ applied environment.SiO by the SIMOX fabrication techniques ₂Layer is kept apart metering circuit layer and silicon base in the chip, and has adopted titanium-platinum-Jin beam leaded structure, can make such chip application in hot environment (〉=150 ℃).The material of sensor flexible member adopts high-elastic materials such as 17-4PH or 17-5PH, structurally adopted circular flat membrane structure, by eutectic bonding or glass dust sintering process sensitive element is encapsulated on the circular flat film of elasticity, by flat membrane structure parameter (thickness and diameter) design, can design the calibration device for high range pressure transducer that range is 100MPa～1000MPa.In addition, because flat film elasticity element 2 directly contacts with measured medium in the screw thread bottom of shell 5, reduced the influence of tube chamber, so this invention has the high frequency sound performance to sensor performance.On elastic element structure, adopt the overload protection design; when pressure surpassed full scale 100% the time; the overload protection arrangement of this sensor will work; the distortion of flexible member is limited; sensor quits work; the flexible member and the sensitive element of protection sensor are not destroyed, and by the protective device design, can make sensor have 30 and accompany above overload capacity.

Adopt SOI technology and various silicon micromachining technique on (100) silicon wafer face, to produce the little solid-state sculptured chip 1 of required SOI silicon, utilize the SIMOX technology to form the SiO of 4000 in silicon base ₂Layer is isolated metering circuit layer and silicon base, deposition 1000 Si on the circuit layer ₃N ₄As the stress matching layer, be used to eliminate silicon and SiO ₂Influence because of the different thermal stress that cause of thermal expansivity.Resistor stripe adopts three folded structures, relief shape, has the high advantage of detection sensitivity.Owing to adopted SOI technology and titanium-platinum-Jin beam leaded structure, this chip can work under the environment of temperature 〉=150 ℃, solved the influence that has leakage current under the high temperature, satisfy rugged surroundings downforce Testing requirement such as high temperature.In order to realize the bonding operation better, the back side of the little solid-state sculptured chip 1 of SOI silicon has been carried out gold-plated.Its structural drawing and microphoto are as shown in Figure 2.

Adopt glass dust sintering or eutectic solder technology the little solid-state sculptured chip 1 of SOI silicon to be encapsulated in the stress raiser of flexible member 2.Wherein the cantilever beam section of flexible member 2 adopts gold-plated processing, and the solder component of eutectic weldering is 98Au/2Si, realizes encapsulation under 380～430 ℃ environmental baseline.Eutectic welding has the weld strength height, welds smoothly, makes the thermal resistance between little solid-state sculptured chip 1 of SOI silicon and the flexible member 2 little, and has resistance to elevated temperatures.

After the present invention is installed on the pipeline, force value is that the high pressure-temperature fluid of P acts on the flexible member 2, flexible member 2 deforms, pass through piezoresistive effect, the arm resistance resistance of the Hui Sideng full-bridge in the little solid-state sculptured chip 1 of the SOI silicon that is encapsulated in flexible member 2 stress raisers is changed pro rata, and relational expression is as follows:

$\frac{\mathrm{\ΔR}}{R_0}=\frac{\mathrm{\Δ\ρ}}{{\mathrm{\ρ}}_0}=\mathrm{\π\σ}---\left(1\right)$

Wherein, R is the resistor stripe resistance, and ρ is a resistivity, and π is a piezoresistance coefficient, and σ is the suffered stress of resistor stripe.

Wheatstone bridge under stabilized power source excitation, the electric signal that the size of output and pressure P is directly proportional, thus record the force value of high temperature fluid.When hydrodynamic pressure P value surpassed the full scale of sensor, overload protection block 3 restriction flexible members 2 continued distortion, reach the purpose of overload protection.By to the gap H among Fig. 1 _GapThe structural parameters of the designing and calculating of size and change protection piece 3 are (as H _PDeng), can make sensor reach overload protection ability more than 30 times.Because flexible member 2 is kept apart the little solid-state sculptured chip 1 of SOI silicon simultaneously with high temperature fluid, so the pressure transducer of this kind structure can bear certain TRANSIENT HIGH TEMPERATURE impact.Equally, (comprise effective diameter 2r and thickness H by the structural parameters that change flexible member 2 _Thick), can make sensor accomplish the wide-range scope.

The high temperature pressure sensor workable in high range, high over loading that the present invention relates to can be used for high temperature (temperature 〉=150 ℃), (pressure is 100MPa～1000MPa), high overload (full scale more than 30 times), height to high pressure Pressure measxurement under the adverse circumstances such as frequency response has the advantages such as precision height, good reliability, can be widely used in The pressure measxurement of military project, field of petrochemical industry.

Claims (4)

1. high temperature pressure sensor workable in high range, high over loading; comprise a shell (5); it is characterized in that; this shell (5) has external thread and inside is provided with cavity; end at shell (5) has outlet cap (6); the cavity end of shell (5) is provided with high temperature switching circuit board (4) successively; overload protection block (3) and flexible member (2); the little solid-state pressure drag chip of SOI silicon (1) is arranged on the flexible member (2); the extension line of the little solid-state pressure drag chip of SOI silicon (1) is connected with high temperature switching circuit board (4) by the gold wire lead-out hole on the overload protection block (3); high temperature card extender (4) is drawn the Pyrotenax line and passed shell (5), and is by outlet cap (6) that the Pyrotenax line is fastening.

2. high temperature pressure sensor workable in high range, high over loading as claimed in claim 1, it is characterized in that the little solid-state pressure drag chip of described SOI silicon (1) adopts glass dust sintering or eutectic bonding technology and encapsulation stress to eliminate the stress raiser that technology is encapsulated in flexible member (2).

3. high temperature pressure sensor workable in high range, high over loading as claimed in claim 1 is characterized in that, described flexible member (2) is by the screw thread bottom of laser bonding at shell (5).

4. high temperature pressure sensor workable in high range, high over loading as claimed in claim 1 is characterized in that its overcurrent protection structure design, and described flexible member (2) and overload protection block (3) adopt laser bonding to be combined as a whole.

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