CN202177477U - Microelectronics pressure sensor - Google Patents

Abstract

The utility model discloses a microelectronics pressure sensor. based on the Hall effect theory, The utility model is provided with a glass substrate layer, wherein a silicon wafer layer is adhered on the glass substrate layer; a silicon oxide layer is adhered on the silicon wafer layer; a concave pit is set on the center position of the lower surface of the silicon wafer layer and forms a cavity with the upper surface of the glass substrate layer; the bottom surface and the opening surface of the concave pit are all squares, wherein the square on the bottom surface is smaller than that on the opening surface; a square silicon resistor layer, which has the same dimension with that of the square on the bottom surface of the concave pit, is adhered on the silicon oxide layer; the four top corners of the silicon oxide layer are respectively provided with a metal electrode slice connected with the silicon resistor layer; the lower surface of the glass substrate layer is fixedly connected with a permanent magnet.

Description

A kind of micro-electronics pressure sensor

Technical field

The utility model relates to pressure transducer, relates in particular to a kind of micro-electronics pressure sensor, belongs to microelectronics technology.

Background technology

The principle of induction of existing pressure transducer mainly comprises two kinds of the induction of two kinds of pressure drags and capacitive sensings.The principle of pressure drag induction is under the pressure effect, and resistance changes on the film because the stress that the film distortion produces causes.The principle of capacitive sensing is under the pressure effect, and a movable electrode of electric capacity is subjected to displacement electric capacity changes in spacing, capacitance variation.The major defect of these two kinds of pressure transducers is: (1) for piezoresistive pressure sensor, this type pressure transducer is very high for designing requirement, and for the size of pressure drag, all there is strict requirement the position of shape and placement.In addition, technological requirement is also very high, because must guarantee that four resistances of formation Wheatstone bridge are equal fully.(2) for capacitance pressure transducer,, subject matter is that electrode is drawn, and owing to there is a movable electrode, causes difficulty of encapsulation, and reliability is relatively poor.

Summary of the invention

The utility model provides a kind of micro-electronics pressure sensor, and technical scheme is following:

A kind of micro-electronics pressure sensor is characterized in that: be chip substrate with the glass substrate, adhere to silicon wafer layer at the glass substrate upper surface; Adhere to silicon oxide layer on the silicon wafer layer, the center position of silicon wafer layer lower surface is provided with a pit, forms cavity between pit and the glass lined bottom upper surface; The bottom surface and the opening surface of pit are square; The bottom surface square adheres to one deck square sensistor layer identical with pit bottom surface square dimensions less than the opening surface square on silicon oxide layer, on its four drift angles, a metal electrode film that is connected with the sensistor layer is set respectively; Two electrodes on one of them diagonal line are used for galvanization; Two electrodes on another diagonal line are used to measure output voltage, and a glass lined bottom lower surface and a permanent magnet are affixed, magnet size >=pit bottom surface square.

Advantage of the utility model and remarkable result

(1) the utility model utilizes Hall effect, and the deformation of silicon fiml pressurized makes the sensistor of its top sense different magnetic field intensitys, makes the voltage of two output electrodes change.

(2) processing technology of the utility model is simple, and whole process flow needs only three mask and need not use very complicated processing step.

Description of drawings

Fig. 1 is the front view of the utility model structure;

Fig. 2 is the vertical view of Fig. 1.

Embodiment

The utility model micro-electronics pressure sensor; Adhere to silicon wafer layer 5 at glass lined bottom 3 upper surfaces, adhere to silicon oxide layer 6 on the silicon wafer layer 5, the center position of silicon wafer layer 5 lower surfaces is provided with a pit; And form cavity between the glass lined bottom upper surface; The bottom surface and the opening surface of pit are square, and the bottom surface square adheres to one deck square sensistor layer 7 identical with pit bottom surface square dimensions less than the opening surface square on silicon oxide layer 6; A metal electrode film 2 that is connected with the sensistor layer respectively is set on its four drift angles; Two electrodes on one of them diagonal line are used for galvanization, and two electrodes on another diagonal line are used to measure output voltage, and glass lined bottom 3 lower surfaces and a permanent magnet 4 are bonding; Magnet size >=pit bottom surface square, the square silicon wafer layer 5 between pit bottom surface square and the silicon oxide layer 6 is defined as silicon fiml 1.

The utility model micro-electronics pressure sensor is based on the Hall effect principle: the induction field intensity that in material, a bit produces arbitrarily is directly proportional with the vector product of current density and magnetic induction density.Pressure changed the change in voltage between two electrodes on the diagonal line changing into sensistor 7.Two electrifying electrodes streams on the diagonal line of the sensistor 7 of silicon fiml 1 top add electric current on two electrodes at a diagonal angle, between two electrodes on another diagonal angle, can record magnitude of voltage, and this magnitude of voltage is corresponding one by one with the pressure size.When silicon fiml 1 above and below pressure is unequal, silicon fiml 1 and sensistor 7 downwarpings.Because permanent magnet 4 produces uneven magnetic field in vertical direction, so the magnetic field intensity that sensistor 7 is sensed changes, and two electrode two ends on the other diagonal line of sensistor 7 just can detect the induced potential with change in pressure.Do the time spent as ambient pressure; Silicon fiml 1 downward distortion can make that sensistor 7 is sensed on the silicon fiml 1 magnetic field intensity increase; Induced potential recording on perpendicular to two electrodes that apply on the direction of current on the sensistor 7 also can increase, and pressure is big more, and induced potential is big more.

Can adopt the thick SOI silicon chip of 400um, the anisotropic wet corrosion forms the thick silicon fiml of 10um, and it is N38 that the film size can be designed to 1000um * 1000um employing model, and magnet size is the magnet of 3mm * 4mm * 1.5mm.

Claims (1)

1. a micro-electronics pressure sensor is characterized in that: be chip substrate with the glass substrate, adhere to silicon wafer layer at the glass substrate upper surface; Adhere to silicon oxide layer on the silicon wafer layer, the center position of silicon wafer layer lower surface is provided with a pit, forms cavity between pit and the glass lined bottom upper surface; The bottom surface and the opening surface of pit are square; The bottom surface square adheres to one deck square sensistor layer identical with pit bottom surface square dimensions less than the opening surface square on silicon oxide layer, on its four drift angles, a metal electrode film that is connected with the sensistor layer is set respectively; Two electrodes on one of them diagonal line are used for galvanization; Two electrodes on another diagonal line are used to measure output voltage, and a glass lined bottom lower surface and a permanent magnet are affixed, magnet size >=pit bottom surface square.

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