CN102494832A - Micro-nano film pressure sensor based on transfer print technology and manufacture method thereof - Google Patents

Abstract

The invention discloses a micro-nano film pressure sensor based on transfer print technology and a manufacture method thereof. The pressure sensor comprises a sensing assembly, an adapter ring, a tube base, a tube cap, an inner lead, a fastening member, a sealing ring, an output cable and a pressure guiding port, wherein the sensing assembly comprises a device substrate, metal electrodes, a prezoresistor and a transfer print medium. By adding the transfer printing medium on the device substrate, the pressure sensor reduces creep deformation and improves isolation performance. The performance and the shape of the transfer print medium used by the pressure sensor ensure good stress transmission and cause no loss beyond stipulated errors. Further, due to the fact that the transfer print technology is compatible with general micro-electronics technology, the pressure sensor can be volume-produced like a silicon-based pressure sensor, is low in price and high in reliability, and simultaneously can be manufactured on different substrates so as to achieve the aims of miniaturization and serve environment resistance by being provided with thin film materials.

Description

Based on micro-nano diaphragm pressure sensor of transfer technique and preparation method thereof

Technical field

The invention belongs to sensor field, be specifically related to a kind of micro-nano diaphragm pressure sensor of making based on transfer technique and preparation method thereof.

Background technology

At present, be that the pressure transducer of sensitive material becomes main flow with various silica-base materials, quantity has occupied the major part of various pressure transducers.Reasons such as compatibility owing to material; This kind sensor is many to be substrate with monocrystalline silicon; Its advantage is cheapness, technical maturity, be particularly suitable for producing in enormous quantities, and has under the normal temperature functional and subsequent conditioning circuit compatibility and very easily make advantages such as integrated transducer or sensor-based system.But the monocrystalline substrate of this type pressure transducer is restricted because of the application of reasons such as impact resistance, interelement isolation in rugged surroundings such as high temperature, radiation, high vibration, impacts.Therefore diaphragm pressure sensor also is developed, and becomes an important branch of pressure transducer, is used widely such as sputtered thin film pressure transducer at present.But because its complex process, process environments is required high, poor with the compatibility of subsequent conditioning circuit, in any case and can not break through the low shortcoming of metal material sensitivity, the application of diaphragm pressure sensor is restricted.

Summary of the invention

To the deficiency of prior art set forth above, the present invention is proposed.

One object of the present invention is to provide a kind of microelectromechanical systems based on transfer technique (MEMS) micro-nano diaphragm pressure sensor.

A kind of MEMS micro-nano diaphragm pressure sensor of making based on transfer technique of the present invention comprises sensory package, adapter ring, base, pipe cap, internal lead, securing member, O-ring seal, output cable and impulse mouth; Sensory package comprises device substrate and tips upside down on the single chip on its upper surface.Single chip further comprises: voltage dependent resistor (VDR); Be formed on the metal electrode at the two ends of voltage dependent resistor (VDR); And be coated in the offset medium on the wafer of voltage dependent resistor (VDR) and metal electrode.

Another object of the present invention provides a kind of preparation method of micro-nano diaphragm pressure sensor.

Preparation method's step of micro-nano diaphragm pressure sensor of the present invention is following:

1) growth one layer insulating on sacrificial substrate;

2) on this insulation course, pass through epitaxy method growth one deck voltage dependent resistor (VDR) layer, adopt photoetching process to press design configuration then and form voltage dependent resistor (VDR);

3) adopt metallization process to press design drawing and make metal electrode;

4) on the wafer of voltage dependent resistor (VDR) for preparing and metal electrode, apply offset medium, cut after the oven dry and form the single chip that has sacrificial substrate;

5) device substrate is provided; Single chip is tipped upside down on the upper surface of device substrate; The upper surface of aiming at device substrate adopts to heat and pressurize and makes both firm being bonded together, and adopts caustic solution to remove sacrificial substrate and insulation course on the single chip then, forms sensory package;

6) adapter ring is provided, on sensory package, pastes adapter ring, after the curing it is installed in the mounting groove of base and meets sb. at the airport the lower surface and firm the welding together of base of device substrate with store energy welding again;

7) adopt bond technology metal electrode and adapter ring to be realized electric the connection, again output cable is welded on the adapter ring with internal lead;

8) output cable passes pipe cap, pipe cap is aimed at base welded again;

9) on output cable, be inserted in O-ring seal and securing member, the securing member of screwing makes O-ring seal seal pipe cap, accomplishes the making of sensor.

Advantage of the present invention:

The MEMS micro-nano diaphragm pressure sensor of making based on transfer technique provided by the invention; It will have the high sensitivity of monocrystalline silicon sensitive material and high temperature resistant, against violent vibration is moving, the metal substrate of large impact adopts transfer technique to combine, remedied the two shortcoming, developed the two advantage; Owing on device substrate, increased offset medium; Thereby reduced creep and strengthened isolation characteristic; The performance of employed offset medium and shape guarantee to transmit stress well and do not cause the loss outside the specification error in this invention; More because this kind transfer technique is compatible with conventional microelectric technique; Thereby still can produce and keep cheapness and high reliability in enormous quantities as silicon substrate pressure sensor, also have membraneous material simultaneously and can be made in the purpose that reaches miniaturization, anti-adverse environment on the different substrates.

Description of drawings

Fig. 1 is the sectional view of the micro-nano diaphragm pressure sensor based on transfer technique of the present invention;

Fig. 2 is the sectional view of the sensory package of the micro-nano diaphragm pressure sensor based on transfer technique of the present invention;

Fig. 3 is the sectional view of the single chip of the micro-nano diaphragm pressure sensor based on transfer technique of the present invention.

Embodiment

Specify sensor of the present invention below in conjunction with accompanying drawing.

As shown in Figure 1: the micro-nano diaphragm pressure sensor based on transfer technique of the present invention comprises sensory package 1, adapter ring 2, base 3, pipe cap 4, internal lead 5, securing member 6, O-ring seal 7, output cable 8 and impulse mouth 9.Wherein sensory package 1 comprisesdevice substrate 16 and tips upside down on the single chip on its upper surface.

As shown in Figure 2, single chip further comprises: voltage dependent resistor (VDR) 14 is formed on themetal electrode 13 at the two ends of voltage dependent resistor (VDR) 14, and is coated in theoffset medium 15 on the wafer of voltage dependent resistor (VDR) 14 andmetal electrode 13.

Wherein, Voltage dependent resistor (VDR) 14 is that single resistance, two resistance constitute a kind of in the half-bridge of Wheatstone bridges and the full-bridge that four resistance constitutes Wheatstone bridges;Offset medium 15 can be benzocyclobutene BCD (benzo-cyclo-butene) or photoresist SU-8;Device substrate 16 is metal substrate or other materials as flexible sheet, and internal lead 5 is spun gold or Si-Al wire.

The preparation method of the micro-nano diaphragm pressure sensor based on transfer technique of the present invention is following:

1) as shown in Figure 3, growth one layer insulating 12 onsacrificial substrate 11, the material ofsacrificial substrate 11 can be monocrystalline silicon, polysilicon or other materials, the material ofinsulation course 12 is that silicon dioxide is done or other insulating material;

2) on thisinsulation course 12, pass through the thick voltage dependent resistor (VDR) layer of epitaxy method growth one deck 100nm～1000nm; Adopt photoetching process to press design configuration then and form voltage dependent resistor (VDR) 14; The material of voltage dependent resistor (VDR) layer can be monocrystalline silicon or other sensitive materials, and voltage dependent resistor (VDR) 14 is that single resistance, two resistance constitute a kind of in the half-bridge of Wheatstone bridges and the full-bridge that four resistance constitutes Wheatstone bridges;

3) adopt metallization process to press design drawing and makemetal electrode 13;

4) on the wafer of voltage dependent resistor (VDR) for preparing and metal electrode, applyoffset medium 15; Cut after the oven dry and form the single chip that has sacrificial substrate; As shown in Figure 3;Offset medium 15 can be benzocyclobutene BCD (benzo-cyclo-butene) or photoresist SU-8, and thickness is 3 μ m～6 μ m, and is as shown in Figure 3;

5)device substrate 16 is provided; Single chip is tipped upside down on the upper surface of device substrate; The upper surface of aiming at device substrate adopts to heat and pressurize and makes both firm being bonded together, and adopts caustic solution to removesacrificial substrate 11 andinsulation course 12 on the single chip then, forms sensory package 1;

6) adapter ring is provided, on sensory package 1, pastes adapter ring 2, after the curing it is installed in the mounting groove of base 3 and meets sb. at the airport the lower surface and base 3 firm the welding together of device substrate with store energy welding again;

7) adopt bond technology with internal lead 5metal electrode 13 to be realized electric the connection with adapter ring 2, output cable 8 is welded on the adapter ring 2 again, internal lead 5 is spun gold or Si-Al wire;

8) output cable 8 passes pipe cap 4, pipe cap 4 is aimed at base 3 welded again;

9) on output cable 8, be inserted in O-ring seal 7 and securing member 6, the securing member 6 of screwing makes 4 sealings of 7 pairs of pipe caps of O-ring seal, accomplishes the making of sensor.

This sensor can the follow-up signal modulate circuit, and this circuit can be installed on the adapter ring, and the output of this sensor is changed into a kind of standard signal output among 0～5VDC, 1～5VDC and the 4～20mADC.

The realization of measuring:

The MEMS micro-nano diaphragm pressure sensor of making based on transfer technique of the present invention is to realize like this measuring:

Introduced by impulse mouth 9 by measuring pressure; Act ondevice substrate 16, the present invention is an example with the metal substrate, but is not limited only to metal substrate; Deformation takes place as the stressed back of flexible sheet in thisdevice substrate 16, makes to produce stress in the bonding voltage dependent resistor (VDR) of being made by transfer technique above that; This stress causes the change of the resistance of voltage dependent resistor (VDR), through impressed voltage produce one with the output of the electric signal that is directly proportional by measuring pressure; This electric signal output is exported by output cable 8 with hundred millivolts of level signals via internal lead 5 switchings, also can further after the signal conditioning circuit processing becomes standard signal, be exported by output cable.

The size of the resistance of voltage dependent resistor (VDR) and stress δ with by wall pressure P following relation is arranged:

${\mathrm{\δ}}_r=\frac{3p}{8{\mathrm{Eh}}^2}[r_o^2(1+\mathrm{\μ})-r^2(3+\mathrm{\μ})]$

${\mathrm{\δ}}_t=\frac{3p}{8{\mathrm{Eh}}^2}[r_o^2(1+\mathrm{\μ})-r^2(1+3\mathrm{\μ})]$

In the formula: δ_r----radial stress

δ_t----tangential stress

The elastic modulus of E----micro-nano sensitive material

The thickness of h----micro-nano sensitive material

r_oThe radius of clean-up of----diaphragm

The Poisson ratio of μ----material

Output voltage V out when the voltage dependent resistor (VDR) of sensor is the Hui Sitong full-bridge is:

V_OUT＝∏?E?δV_in

In the formula: ∏ is the piezoresistance coefficient of micro-nano sensitive material;

δ is radial stress and tangential stress sum

V_InBe the driving voltage that sensor is applied

Thereby, output voltage be directly proportional by measuring pressure, obtain by the size of measuring pressure according to output voltage.

It should be noted that at last the purpose of publicizing and implementing example is to help further to understand the present invention, but it will be appreciated by those skilled in the art that: in the spirit and scope that do not break away from the present invention and appended claim, various replacements and modification all are possible.Therefore, the present invention should not be limited to the disclosed content of embodiment, and the scope that the present invention requires to protect is as the criterion with the scope that claims define.

Claims (10)

1. micro-nano diaphragm pressure sensor; Said sensor comprises sensory package (1), adapter ring (2), base (3), pipe cap (4), internal lead (5), securing member (6), O-ring seal (7), output cable (8) and impulse mouth (9); Said sensory package (1) comprises device substrate (16) and tips upside down on the single chip on its upper surface; It is characterized in that said single chip further comprises: voltage dependent resistor (VDR) (14); Be formed on the metal electrode (13) at the two ends of voltage dependent resistor (VDR) (14); And be coated in the offset medium (15) on the wafer of said voltage dependent resistor (VDR) (14) and metal electrode (13).

2. sensor as claimed in claim 1 is characterized in that, said voltage dependent resistor (VDR) (14) is that single resistance, two resistance constitute a kind of in the half-bridge of Wheatstone bridges or the full-bridge that four resistance constitutes Wheatstone bridges.

3. sensor as claimed in claim 1 is characterized in that, said offset medium (15) is benzocyclobutene BCD or photoresist SU-8.

4. sensor as claimed in claim 1 is characterized in that, said device substrate (16) is metal substrate or other materials as flexible sheet.

5. sensor as claimed in claim 1; It is characterized in that; The said follow-up signal modulate circuit that on said sensor, connects, said circuit is installed on the said adapter ring, and the output of said sensor is changed into a kind of standard signal output among 0～5VDC, 1～5VDC and the 4～20mADC.

6. the preparation method of a micro-nano diaphragm pressure sensor is characterized in that, concrete steps are following:

1) growth one layer insulating on sacrificial substrate, the material of said sacrificial substrate is monocrystalline silicon, polysilicon or other materials, the material of said insulation course is that silicon dioxide is done or other insulating material;

2) on said insulation course, pass through epitaxy method growth one deck voltage dependent resistor (VDR) layer, adopt photoetching process to press design configuration then and form voltage dependent resistor (VDR);

3) adopt metallization process to press design drawing and make metal electrode;

4) on the wafer of said voltage dependent resistor (VDR) for preparing and said metal electrode, apply offset medium, cut after the oven dry and form the single chip that has sacrificial substrate;

5) device substrate is provided; Said single chip is tipped upside down on the upper surface of said device substrate; The upper surface of aiming at said device substrate adopts to heat and to pressurize and makes both firm being bonded together; Adopt caustic solution to remove sacrificial substrate and insulation course on the said single chip then, form sensory package;

6) adapter ring is provided, on said sensory package, pastes adapter ring, after the curing it is installed in the mounting groove of base, meet sb. at the airport the lower surface and firm the welding together of base of device substrate with store energy welding again;

7) adopt bond technology said metal electrode to be realized electric the connection with said adapter ring, again output cable is welded on the said adapter ring with internal lead;

8) output cable passes pipe cap, said pipe cap is aimed at said base welded again;

9) on said output cable, be inserted in O-ring seal and securing member, the securing member of screwing makes said O-ring seal seal said pipe cap, accomplishes the making of sensor.

7. preparation method as claimed in claim 6; It is characterized in that; In step 2) in, the thickness of said voltage dependent resistor (VDR) layer is 100nm～1000nm, said voltage dependent resistor (VDR) is that single resistance, two resistance constitute a kind of in the half-bridge of Wheatstone bridges and the full-bridge that four resistance constitutes Wheatstone bridges.

8. preparation method as claimed in claim 6 is characterized in that, in step 4), said offset medium is benzocyclobutene BCD or photoresist SU-8, and thickness is 3 μ m～6 μ m.

9. preparation method as claimed in claim 6 is characterized in that, in step 5), said device substrate is metal substrate or other materials as flexible sheet.

10. preparation method as claimed in claim 6 is characterized in that, in step 7), said internal lead is spun gold or Si-Al wire.

Images