CN109724721A - The SiC high-temp pressure sensor and its manufacturing method of non-leaded package - Google Patents

Abstract

The SiC high-temp pressure sensor and its manufacturing method of present invention offer non-leaded package, comprising: p-SiC wafer is thinned, successively grows p-SiC layers and n-SiC layers in the face Si；The sensitive diaphragm with rectangular embossment structure is formed in the face C；Patterned mask layer is formed on n-SiC layers, carries out light engraving erosion and pickling forms sensitive resistance item；Barrier layer is formed in the face Si by thermal oxide；Selective corrosion is carried out to it, obtains contact window on sensitive resistance top；Ni/Ti/Ni/Pt metal layer is formed in the face Si；By metallic layer graphic；It is contacted by contact window with sensitive resistance item and forms electrode and pad；High annealing makes sensitive resistance item and metal electrode form Ohmic contact, and forms static-pressure compensation unit；Manufacture encapsulation matrix, at chip bonding pad deposit Ag nano particle, by Pt lead pass through fairlead and with Ag nanoparticles sinter, then in gap location filling glass melten gel.

Description

The SiC high-temp pressure sensor and its manufacturing method of non-leaded package

Technical field

The invention belongs to wide band gap semiconductor device preparation technical fields, and in particular to a kind of SiC high of non-leaded package Temperature and pressure force snesor and its manufacturing method.

Technical background

Sensor technology is the important symbol of development of modern scientific technology level, and wherein pressure sensor is that application is the widest General one kind.Pressure sensor is a kind of semiconductor electronic component that can convert this analog signal of pressure to electric signal, with The development of semiconductor technology and MEMS technology, main material of the people using silicon as pressure sensor take capacitor, pressure drag etc. Diversified forms, its main feature is that small in size, light weight, accuracy height, good temp characteristic etc..As people are to more extremely especially The research and probe of hot environment gos deep into, and pressure sensor needs to work in the presence of a harsh environment, such as in space flight and aviation, nuclear energy skill The pressure measurement in the fields such as art, petrochemical industry, geothermal exploration and automotive electronics is needed in 350 DEG C of even higher temperature environments Lower progress.Therefore following reason limit application of the sensor based on silicon materials under the conditions of high temperature hostile: 1, by Narrow in silicon material forbidden band width, high temperature resistant and radiation resistance are poor；2, silicon materials are easy to chemically react with medium, It is oxidized or corrodes；3, silicon materials are easy to happen mechanical performance degeneration under the high temperature conditions.

Carbofrax material is gradually paid attention to by people due to its unique physical property and electrology characteristic.It is the third generation The representative of semiconductor material with wide forbidden band, compared with the existing Si being widely used as pressure sensor material, SiC material has excellent The excellent material properties such as good broad-band gap, high heat conductance, high mechanical strength, anti-radiation, anticorrosive and high-temperature stability are systems Make the ideal material of high-temperature device.SiC high-temp pressure sensor is because having high heatproof, small in size, long service life, reaction spirit It is quick, be not required to maintenance the features such as, will be widely used in internal combustion engine, oil drilling of the vehicles such as automobile, aircraft, ship etc. neck The pressure detecting in domain.

As the continuous development and progress of technology is made in high-temp pressure sensor, constantly promoted using temperature, and with This simultaneously, the encapsulating structure of high-temp pressure sensor does not make corresponding changes, so as to cause high-temp pressure sensor failure The reason of often caused by lead in encapsulating structure heat fatigue and concussion damage.Researchers are in order to further increase high-temperature high-pressure The ultimate-use (limiting service) temperature of force snesor is made great efforts to find in links such as the materials, chip structure, chip package of sensor and be broken through Mouthful.Compared with conventional pressure sensor, the SiC high-temp pressure sensor of non-leaded package has better reliability, higher Operating temperature.The SiC high-temp pressure sensor of non-leaded package is the trend place of future pressure sensor development.

Summary of the invention

The present invention is to carry out to solve the above-mentioned problems, it is therefore intended that goes out a kind of SiC high-temperature high-pressure of non-leaded package Force snesor and its manufacturing method, it is ensured that the better reliability that sensor works in the presence of a harsh environment, practical Withstanding operating temperatures It is higher, and sensitivity is improved conscientiously.The present invention to achieve the goals above, uses following scheme:

<manufacturing method>

The present invention provides a kind of manufacturing method of the SiC high-temp pressure sensor of non-leaded package, which is characterized in that including Following steps: p-SiC wafer is thinned step 1., by the thinned successive isoepitaxial growth p- in the face SiC wafer Si SiC layer with n-SiC layers；Step 2., which is formed in the face C of SiC wafer using femtosecond laser process, has rectangular embossment structure Sensitive diaphragm；Step 3. forms graphical Ni metal foil mask using photoetching process, electron beam evaporation process on n-SiC layers Layer carries out light engraving erosion by RIE etching apparatus, forms sensitive resistance with the mode that pickling removes graphical Ni metal foil mask layer Item；Step 4. forms SiO in the face Si by thermal oxide₂Barrier layer；Again by photoetching process, wet corrosion technique to SiO₂Stop Layer carries out selective corrosion, obtains contact window on sensitive resistance top, removes oxide and sample surfaces with BOE solution Other elements；Step 5. forms Ni/Ti/Ni/Pt metal in the face wafer Si SiC by photoetching process, e-book evaporation technology Layer；Again by photoetching process, wet corrosion technique by Ni/Ti/Ni/Pt metallic layer graphic；Patterned Ni/Ti/Ni/Pt Metal layer contacts with sensitive resistance item by contact window and forms electrode and pad structure；Step 6. is made by high annealing Sensitive resistance item and Ni/Ti/Ni/Pt patterned metal electrode form Ohmic contact, and sensitive resistance item and patterned metal Electrode forms the static-pressure compensation unit with wheatstone bridge configuration, obtains SiC chip of high-temp pressure sensor；Step 7. system AlN material package matrix is made, then deposits Ag nano-particle material at the pad of SiC chip of high-temp pressure sensor, Pt is connect It touches lead and passes through encapsulation matrix fairlead, and Ag nano-particle material and Pt contact lead-wire are sintered, by chip and encapsulation matrix It is inverted connection, then around Ag nano-particle material, SiC chip of high-temp pressure sensor and encapsulation matrix gap location filling glass Glass melten gel, to enhance the fixation to chip.

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: in step 1, SiC wafer be thinned after with a thickness of 120~130 μm, thinning process can reduce subsequent deep chamber The technology difficulty of processing, thickness are maintained at 120 μm or more the overall structural strengths that can then guarantee wafer processing.

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: in step 1, for the p-SiC layer of successively isoepitaxial growth with a thickness of 4~5 μm, doping concentration is 3 × 10¹⁸cm^-3 (± 15%), n-SiC layers with a thickness of 2 μm, doping concentration is 1 × 10¹⁹cm^-3(± 15%).The doping used of p/n type epitaxial layer is dense It spends and is while reaching the optimal coefficient of strain of material and meeting the most suitable value of chip sensitivity requirement, the N-shaped epitaxial layer later period passes through Light engraving etching technique formed pressure drag item, pressure drag item with a thickness of 2 μm and be slightly larger than N-shaped epitaxial layer, this thickness is by ANSYS software Carry out the optimal value that chip is emulated without encapsulating structure thermodynamics.

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: in step 2, cleaning 4 inches of 4H-SiC epitaxial wafers after epitaxial growth, and cleaning process includes using Acetone soln greater than 30 DEG C less than 55 DEG C be cleaned by ultrasonic within 15 minutes, surpass within 10 minutes with the ethanol solution greater than 30 DEG C Sound cleaning, then be cleaned by ultrasonic within 10 minutes with the deionized water greater than 30 DEG C, the ultrasound three times of acetone, ethyl alcohol and deionized water The ultrasonic frequency range that cleaning is selected is 40-80kHz, with pure N₂Gas blows away surface deionized water under dustfree environment, in 65- It is cooled to room temperature after carrying out drying and processing in 75 DEG C of heating plates to sample；By sample as scanning sample stage, femto-second laser is used Continuous scanning processing, the harmonic wavelength 518nm of laser use, mean power are carried out to the face C of SiC wafer 380mW, pulse frequency 100kH, pulse width 350fs, the position and motion profile that laser focuses are controlled by digital scanner, quick The layout scenarios of sense diaphragm are imported and are pre-processed by cad tools, and process time is according to the number of used parallel laser beam Depending on；Sensitive diaphragm includes: that outer edge cross section is rectangular pit, and be formed in the middle part of the pit, outer edge cross section is Rectangular embossment structure, pit and embossment structure have common symmetrical centre, and side wall with SiC chip of high-temp pressure sensor In 12~15 ° of inclinations.

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: in step 3, photoetching process forms graphical Ni for electron beam evaporation process and is photoresist exposure mask, graphical Ni Metal foil mask layer is that the shallow etching process of RIE does exposure mask, and etching depth is not less than 2 μm, and sensitive resistance item should be than n-SiC thickness 0.05~0.15 μm, shallow etching gas is SF₆With O₂Gaseous mixture, concentration is followed successively by 80sccm and 20sccm, and etching institute is diligent Rate is 150W, and beam power used in electron beam evaporation is 60KW, and evaporation of metal rate is no more than

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: in step 4, the temperature of thermal oxide is 1100 DEG C~1200 DEG C, and the time is 4~6h, the SiO of formation₂Barrier layer With a thickness of 3~6 μm.

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: in step 6, high-temperature annealing process is in N₂Under atmosphere and 950 DEG C at a temperature of rapid thermal annealing 1min.

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: in step 7, part corresponding with SiC chip of high-temp pressure sensor is equipped with rectangular in encapsulation matrix Base cavity, the side length of the base cavity is greater than the pit side length on sensitive diaphragm, and is less than the surrounded region of pad structure Side length.

Preferably, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have Following characteristics: matrix shape, thermocouple hole, base cavity etc. are added using casting and forming and machinery in encapsulation matrix manufacturing process Work mode degreases by encapsulation matrix polishing, polishing before encapsulation and waits organic impurities and burr；Matrix and chip coupling part Equipped with base cavity, base cavity be it is rectangular, side length slightly larger than tool card-cut rectangular sensitive diaphragm pit top surface side length, be less than Pad location；Encapsulation process introduces nanometer Ag interconnection technique and the direct adhering technique of chip (DCA technology), in SiC high temperature Ag nano-particle material is deposited at four pads of pressure sensor chip, Ag nano-particle material includes: particle diameter≤900nm Ag particle and nano-solder paste, also, Ag particle accounting be 65~80wt.%, by Pt contact lead-wire pass through encapsulation matrix lead SiC chip of high-temp pressure sensor is upside down under standard atmospheric pressure dustfree environment and is sealed in base cavity by hole, with extraneous ring Border obstructs completely, and by pad alignment package matrix fairlead, the pad for depositing Ag nano particle and Pt contact lead-wire are sintered (sintering temperature≤300 DEG C) are attached, and are slowly pressurizeed in sintering process；It is to be sintered finish be cooled to room temperature after at Ag nanometers Grain surrounding, chip and AlN encapsulation matrix gap filling pyroceram melten gel enhance fixing intensity of the chip on packaging body.

<sensor>

In addition, the present invention also provides a kind of SiC high-temperature high-pressures using non-leaded package prepared by above-mentioned<manufacturing method> Force snesor characterized by comprising SiC chip of high-temp pressure sensor includes: it is formed down by SiC wafer deep etching Portion has the sensitive diaphragm of rectangular embossment structure, and the p-SiC layer being formed on sensitive diaphragm is formed on p-SiC layers outside by N-shaped Prolong sensitive resistance item made of layer etching, the SiO being formed on p-SiC layers and sensitive resistance item₂Barrier layer is formed in SiO₂Resistance Contact window in barrier and above sensitive resistance item, and contact and formed with sensitive resistance item by contact window The patterned Ni/Ti/Ni/Pt metal layer of electrode and pad structure；And encapsulation part, inverted SiC high temperature is connected for encapsulating Pressure sensor chip includes: encapsulation matrix, the Ag nano particle deposited at the pad of SiC chip of high-temp pressure sensor Material is formed in encapsulation matrix, the fairlead for allowing Pt contact lead-wire to pass through to be connected with Ag nano-particle material, It is filled in the glass melten gel of SiC chip of high-temp pressure sensor Yu encapsulation matrix gap location, and the heat being formed in encapsulation matrix Galvanic couple hole.

Further, the SiC high-temp pressure sensor of non-leaded package provided by the invention can also have the feature that Sensitive diaphragm includes: that outer edge cross section is rectangular pit, and be formed in the middle part of the pit, outer edge cross section is rectangular Embossment structure, pit and embossment structure have common symmetrical centre with SiC chip of high-temp pressure sensor, and side wall is in 12 ~15 ° of inclinations are equipped with rectangular matrix sky in encapsulation matrix towards the not connected part of SiC chip of high-temp pressure sensor Chamber, the side length of the base cavity is greater than the pit side length on sensitive diaphragm, and is less than the side length in the surrounded region of pad structure, Ag nano-particle material includes: particle diameter≤900nm Ag particle and nano-solder paste, also, Ag particle accounting be 65~ The bonding region gross area is less than static-pressure compensation cell electrode graphics area on 80wt.%, SiC chip of high-temp pressure sensor A quarter.

The action and effect of invention

1, the present invention is directed to the manufacture of SiC high-temp pressure sensor, proposes the completely new manufacture of one kind and packaging technology is real Existing method.SiC wafer is thinned, by the thinned successive isoepitaxial growth layer n-SiC and p- in the face SiC wafer Si SiC layer；The rectangular sensitive diaphragm of embossment structure is formed using femtosecond laser process in the face C of SiC wafer；In SiC wafer Graphical Ni metal foil mask layer is formed using photoetching process, electron beam evaporation process on the n-SiC layer of piece extension, passes through RIE Etching apparatus carries out light engraving erosion, forms sensitive resistance item with the mode that pickling removes graphical Ni metal foil mask layer；By SiC Wafer thermal oxide forms SiO in the face Si₂Barrier layer, by photoetching process, wet corrosion technique to SiO₂It is selected on barrier layer The corrosion of selecting property, obtains contact window on sensitive resistance top, other yuan of oxide and sample surfaces are removed with BOE solution Element；Ni/Ti/Ni/Pt metal layer is formed in the face wafer Si SiC by photoetching process, e-book evaporation technology, again by Photoetching process, wet corrosion technique by metallic layer graphic, contacted by contact window with sensitive resistance item and formed electrode with Pad structure；SiC wafer piece is subjected to high annealing, makes sensitive resistance item and Ni/Ti/Ni/Pt patterned metal electrode shape At Ohmic contact, so far SiC chip of high-temp pressure sensor part completes；AlN material package matrix is manufactured, in SiC high Ag nano-particle material is deposited at four pads of temperature and pressure sensor chip, and Pt contact lead-wire is passed through into encapsulation matrix fairlead, Ag nano-particle material is deposited at SiC chip of high-temp pressure sensor pad, by Ag nano-particle material and Pt contact lead-wire Sintering is attached, and around Ag nano-particle material, chip and AlN encapsulation matrix gap filling glass melten gel, is enhanced pair The fixation of chip.

2, the present invention introduces nanometer Ag interconnection technique in the encapsulation process of SiC high-temp pressure sensor, realizes SiC Chip of high-temp pressure sensor is inverted without lead and is encapsulated, and is directly connected to using pad and Ag nano particle, carries out not against lead Signal transmission efficiently avoids the sensor failure because of caused by lead heat fatigue and concussion damage, has higher use Temperature and stronger shock resistance；The electrode pattern of the static-pressure compensation unit of wheatstone bridge configuration is to be inverted encapsulation simultaneously, It is sealed in base cavity under standard atmospheric pressure dustfree environment, is obstructed completely with external environment, it is compact-sized, space is saved, no Increase encapsulating structure accessory, and internal pressure is made to be in stable state, further ensures the measurement accuracy of sensor.

3, the present invention sets the suspension of four side formulas for static-pressure compensation unit and is encapsulated in base cavity top and sensitive diaphragm Combined type stepped construction is formed, bonding region (with the face of glass sol binder) is only located at four edge of chip, bonding region The gross area is less than a quarter of static-pressure compensation cell electrode figure, and the non-adhering area bottom surface of static-pressure compensation unit is nonadherent On to differential pressure Sensitive Apparatus on glass fixed polar plate, influence the performance of static-pressure compensation unit by outer enclosure structure It is small, and make it that there is very high resistance to vibration, signal drift significantly reduces, and realizes high stable, the height of pressure signal Precisely acquisition.The differential pressure measurement value of sensitive diaphragm is compensated using the differential pressure measurement value of static-pressure compensation unit, realizes SiC The pressure error of base pressure sensor compensates, and efficiently solves the problems, such as that pressure error is dispersed, and improves the comprehensive essence of sensor Degree.

4, the present invention combines nanometer Ag interconnection technique and the direct adhering technique of chip, proposes law temperature joining (nanometer Ag particle sintering temperature≤300 DEG C) new method, avoid in conventional encapsulation process manual dispensing glue film and easily spill into electrode Occur burrs on edges or external bridging except area, after electrode moulding, causes short circuit of polar after sealing-in, lead to asking for component failure Topic；Nanometer Ag interconnection technique requires sintering temperature lower, sensor core caused by further avoiding high-temperature soldering in the process Piece edge deformation or due to temperature it is excessively high caused by Problem of Failure；In addition, for encapsulating structure part fairlead, thermocouple hole, Base cavity is all made of method removal weld bond greasy dirt of the abrasive paper for metallograph sanding and polishing weld bond of 1200 mesh of granularity etc. before encapsulation to be had Machine impurity and burr efficiently solve the problems, such as the sand holes and spot of weld seam appearance after sintering.

5, the present invention carries out deep pit structure processing in the face C of SiC sample using femtosecond laser technique, breaches traditional deep Etching technique is difficult to SiC material the limitation etched, solves photo etched mask in the process since etching selection ratio is too small and etching The problem of the deficiency of mask thicknesses caused by overlong time makes sensitive diaphragm working depth reach 60-70 μm, while laser focuses Position and motion profile are controlled by digital scanner, and diaphragm layout scenarios are imported and pre-processed by cad tools, are more guaranteed The precision of processing structure, avoids the cumbersome processing step of metal sputtering exposure mask, can monitor at any time working depth to adjust Machined parameters, advanced optimize in this technique, and the mode for improving the number of parallel laser beam also can be used, and accelerate one single chip Process velocity or multiple chips simultaneous processing.

6, by the present invention in that with card-cut rectangular sensitive diaphragm, for round sensitive diaphragm structures most of at present For sensor, such structure stress rear axle output is larger, and structural edge and pressure drag item are in parastate, are conducive to linearly press The linear convergent rate of force signal, internal rectangular embossment structure mass block make when choosing size appropriate and sensitive diaphragm thickness The stress compression and draw direction on sensitive diaphragm surface change in homogenous linear, and the ideal characterisitics of pressure measurement is reached with this.

7, the SiC high-temp pressure sensor of non-leaded package produced by the present invention, is melted using microelectronics and micromachined The production of conjunction technology, precision is high, stability is good, high reliablity, consistency are good, and rational technology is easy to produce in enormous quantities, can be well Demand of the high-temperature systems to high-precision pressure sensor of industry automatic control is met, there is wide development and application prospect.

Detailed description of the invention

Fig. 1 is the flow chart of the manufacturing method of non-leaded package SiC high-temp pressure sensor in the embodiment of the present invention；

Structural schematic diagram of the Fig. 2 for SiC wafer in step 1 of the embodiment of the present invention before thinned；

Structural schematic diagram of the Fig. 3 for SiC wafer in step 1 of the embodiment of the present invention after thinned；

Fig. 4 is successive isoepitaxial growth p-SiC layers and n-SiC of the face SiC wafer Si in step 1 of the embodiment of the present invention Structural schematic diagram after layer；

Fig. 5 is that processing forms the structural schematic diagram after sensitive membrane in step 2 of the embodiment of the present invention；

Fig. 6 is the three-dimensional structure diagram of sensitive diaphragm in the embodiment of the present invention

Fig. 7 is the top view of sensitive diaphragm in the embodiment of the present invention；

Fig. 8 is to form the structural schematic diagram after graphical Ni metal foil mask layer in step 3 of the embodiment of the present invention；

Fig. 9 is to form the structural schematic diagram after graphical Ni metal foil mask layer in step 3 of the embodiment of the present invention；

Figure 10 is that the structural schematic diagram after sensitive resistance item is formed in step 3 of the embodiment of the present invention；

Figure 11 is that the top view after sensitive resistance item is formed in step 3 of the embodiment of the present invention；

Figure 12 is to form SiO in step 4 of the embodiment of the present invention₂Structural schematic diagram behind barrier layer；

Figure 13 is that the structural schematic diagram after contact window is formed in step 4 of the embodiment of the present invention；

Figure 14 is that the structural schematic diagram after photoresist exposure mask is formed in step 5 of the embodiment of the present invention；

Figure 15 is to form the structural schematic diagram after graphical Ni/Ti/Ni/Pt metal layer in step 5 of the embodiment of the present invention；

Figure 16 is to wash away photoresist in step 5 of the embodiment of the present invention to form the structure after graphical Ni/Ti/Ni/P metal Schematic diagram；

Figure 17 is the top view of the pad and electrode structure that are formed in step 5 of the embodiment of the present invention；

Figure 18 is the structural schematic diagram of SAlN material package matrix involved in step 7 of the embodiment of the present invention；

Figure 19 is the top view of SAlN material package matrix involved in step 7 of the embodiment of the present invention；

Figure 20 is the structure chart after depositing Ag nano-particle material at pad in step 7 of the embodiment of the present invention；

Figure 21 is the top view after depositing Ag nano-particle material at pad in step 7 of the embodiment of the present invention；

Figure 22 is that the inversion of SiC chip of high-temp pressure sensor is packaged in base cavity in step 7 of the embodiment of the present invention Structural schematic diagram behind side；

Figure 23 is to be attached Ag nano particle and the sintering of Pt contact lead-wire in step 7 of the embodiment of the present invention and fill glass Structural schematic diagram after glass melten gel.

Specific embodiment

Below in conjunction with attached drawing to the SiC high-temp pressure sensor of non-leaded package of the present invention and its manufacturing method Specific embodiment is described in detail.

<embodiment>

As shown in Figure 1, the manufacturing method of the SiC high-temp pressure sensor of non-leaded package provided in this embodiment, including Following steps:

(1) as shown in Figures 2 and 3, p-SiC wafer 100 is thinned to 130 μm, dotted line show the portion being thinned in Fig. 3 Point；As shown in figure 4, the successive isoepitaxial growth in the face Si of the SiC wafer 100 after being thinned is with a thickness of 5 μm, doping concentration 3 × 10¹⁸cm^-3The p-SiC layer 101 of (± 15%), growth thickness are 2 μm, and doping concentration is 1 × 10¹⁹cm^-3(± 15%) N-SiC layer 102.

(2) as shown in Fig. 5~7, embossment structure is formed using femtosecond laser process in the face C of p-SiC wafer 100 Rectangular sensitive diaphragm 103；As shown in FIG. 7 and 8, sensitive diaphragm 103 is in " rectangular-ambulatory-plane " shape, comprising pit 103a and is formed in recessed The embossment structure 103b of 103a centre is cheated, the top surface pits 103a is 1600 μm of square patterns 104 of side length (single SiC The square body structure that chip of high-temp pressure sensor S1 is 2500 μm of side length), the top surface embossment structure 103b is 600 μm of side length Square pattern 105, pit 103a depth be 60-70 μm (in conjunction be thinned after actual (real) thickness, make the thickness of the bottom pit 103a Degree reaches 60 ± 0.2 μm), pit 103a and embossment structure 103b and chip S1 integrally have common symmetrical centre and are side Wall has 12~15 ° of inclined inclined-planes 106, this structure is to carry out chip by ANSYS software to emulate without encapsulating structure thermodynamics Obtained preferred structure, the thickness of pit top surface side length, embossment structure top surface side length and pit bottom is all in accordance with predetermined core Piece side length is designed.

(3) as shown in figure 9, being formed graphically on the surface of n-SiC layer 102 using photoetching process, electron beam evaporation process Ni metal foil mask layer 107；As shown in FIG. 10 and 11, light engraving erosion is carried out by RIE etching apparatus, is removed with pickling graphical The mode of Ni metal foil mask layer 107 forms sensitive resistance item 108；

(4) as shown in figure 12, by 100 thermal oxide of p-SiC wafer, SiO is formed in the entire upper surface in the face Si₂Barrier layer 109；As shown in figure 13, by photoetching process, wet corrosion technique to SiO₂Barrier layer 109 carries out selectivity windowing corrosion, 108 top of sensitive resistance item obtains contact window 110, and the other elements of oxide and sample surfaces are removed with BOE solution；

(5) as shown in figure 14, graphical photoresist exposure mask is formed in the face Si of p-SiC wafer 100 by photoetching process 111；As shown in figure 15, Ni/Ti/Ni/Pt metal layer 112 is formed on Si using electron beam evaporation process；As shown in figure 16, It washes away photoresist and forms patterned metal electrode 113, contacted by contact window 110 with sensitive resistance item 108 and formed such as figure Pad 114 shown in 17 and 115 structure of electrode are equipped with 114 structure of pad everywhere in the present embodiment altogether, are located at rectangular chip Four corners；

(6) p-SiC wafer 100 is subjected to high annealing, keeps sensitive resistance item 108 and Ni/Ti/Ni/Pt graphically golden Belong to electrode 113 and form Ohmic contact, so far the part SiC chip of high-temp pressure sensor S1 completes；

(7) as shown in Figures 18 and 19, AlN material package matrix 116 is manufactured, encapsulation matrix 116 includes four fairleads 117, thermocouple hole 118 with and a base cavity 119, four fairleads 117 it is corresponding with four pads 114 respectively； As shown in Figure 20 to 23, Ag nano-particle material 120 is deposited at tetra- pads 114 of SiC chip of high-temp pressure sensor S1, it will Pt contact lead-wire 121 passes through encapsulation matrix fairlead 117, and Ag nano-particle material 120 and the sintering of Pt contact lead-wire 121 are carried out Connection, around Ag nano-particle material 120, the gap location of SiC chip of high-temp pressure sensor S1 and AlN encapsulation matrix 116 The enhancing of filling glass melten gel 122 is fixed, and the SiC high-temp pressure sensor S of non-leaded package is obtained.

As shown in figure 23, in the present embodiment, the SiC high-temp pressure sensor S of final non-leaded package obtained includes SiC Chip of high-temp pressure sensor S1 and encapsulation part S2 two parts.As shown in Figure 16, SiC chip of high-temp pressure sensor S1 includes: There is the sensitive diaphragm 103 of rectangular embossment structure 103b by the lower part that SiC wafer deep etching is formed, be formed in sensitive diaphragm P-SiC layer 101 on 103 is formed on p-SiC layer 101 sensitive resistance item 108 made of being etched as N-shaped epitaxial layer 102, shape At the SiO on p-SiC layer 101 and sensitive resistance item 108₂Barrier layer 109, is formed in SiO₂On barrier layer 109 and it is located at quick Pressure-sensitive hinders the contact window 110 of 108 top of item, and is contacted by contact window 110 with sensitive resistance item 108 and form weldering The patterned Ni/Ti/Ni/Pt metal layer 113 of disk 114 and 115 structure of electrode.As shown in figure 23, encapsulation part S2 is for encapsulating Inverted SiC chip of high-temp pressure sensor S1 is connected, it includes: encapsulation matrix 116, in SiC chip of high-temp pressure sensor The Ag nano-particle material 120 deposited at the pad 114 of S1 is formed in encapsulation matrix 116, for allowing Pt contact lead-wire 121 Across the fairlead 117 to be connected with Ag nano-particle material, it is filled in SiC chip of high-temp pressure sensor S1 and envelope Fill the glass melten gel 122 of 116 gap location of matrix, and the thermocouple hole 119 being formed in encapsulation matrix 116；In the present embodiment, heat Galvanic couple hole 119 is formed in 116 middle of encapsulation matrix, and extends from bottom towards base cavity 119.

Since with structure as above, the SiC high-temp pressure sensor S of non-leaded package provided by the present invention is in severe ring The better reliability to work under border, practical Withstanding operating temperatures are more than 320 DEG C, and sensitivity reaches 5.24 μ V/V/Kpa.

Above embodiments are only the illustration done to technical solution of the present invention.No lead envelope according to the present invention The SiC high-temp pressure sensor and its manufacturing method of dress are not merely defined in described content in the embodiment above, and It is to be defined by the scope defined by the claims..What those skilled in the art of the invention were done on the basis of the embodiment appoints What modify or supplement or equivalence replacement, all in claim range claimed of the invention.In addition, not being described in detail in text Content is the prior art.

Claims (10)

1. a kind of manufacturing method of the SiC high-temp pressure sensor of non-leaded package, which comprises the steps of:

P-SiC wafer is thinned step 1., by successive isoepitaxial growth p-SiC layers thinned of the face SiC wafer Si With n-SiC layers；

Step 2. forms the sensitive diaphragm with rectangular embossment structure in the face C of SiC wafer using femtosecond laser process；

Step 3. forms graphical Ni metal foil mask layer using photoetching process, electron beam evaporation process on n-SiC layers, passes through It carries out light engraving erosion and forms sensitive resistance item with the mode that pickling removes graphical Ni metal foil mask layer；

Step 4. forms SiO in the face Si by thermal oxide₂Barrier layer；Again by photoetching process, wet corrosion technique to SiO₂Stop Layer carries out selective corrosion, obtains contact window on sensitive resistance top；

Step 5. forms Ni/Ti/Ni/Pt metal layer in the face wafer Si SiC by photoetching process, e-book evaporation technology；Again It is secondary by photoetching process, wet corrosion technique by Ni/Ti/Ni/Pt metallic layer graphic；Patterned Ni/Ti/Ni/Pt metal Layer contacts with sensitive resistance item by contact window and forms electrode and pad structure；

Step 6. makes sensitive resistance item and Ni/Ti/Ni/Pt patterned metal electrode form Ohmic contact by high annealing, and And sensitive resistance item and Ni/Ti/Ni/Pt patterned metal electrode form the static-pressure compensation list with wheatstone bridge configuration Member obtains SiC chip of high-temp pressure sensor；

Step 7. manufactures AlN material package matrix, then Ag nano particle is deposited at the pad of SiC chip of high-temp pressure sensor Pt contact lead-wire is passed through encapsulation matrix fairlead, and Ag nano-particle material and Pt contact lead-wire is sintered by material, is then existed Around Ag nano-particle material, SiC chip of high-temp pressure sensor and encapsulation matrix gap location filling glass melten gel.

2. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 1, it is characterised in that:

Wherein, in the step 1, SiC wafer be thinned after with a thickness of 120~130 μm.

3. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 1, it is characterised in that:

Wherein, in the step 1, the p-SiC layer of successively isoepitaxial growth with a thickness of 4~5 μm, doping concentration is 3 × 10¹⁸cm^-3, n-SiC layers with a thickness of 2 μm, doping concentration is 1 × 10¹⁹cm^-3。

4. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 1, it is characterised in that:

Wherein, in the step 2, continuous scanning processing is carried out with C face of the femto-second laser to SiC wafer, laser focuses Position and motion profile controlled by digital scanner, the layout scenarios of sensitive diaphragm are imported and are pre-processed by cad tools,

Sensitive diaphragm includes: that outer edge cross section is rectangular pit, and is formed in pit middle part, outer edge cross section as just The embossment structure of shape,

Pit and embossment structure have common symmetrical centre with SiC chip of high-temp pressure sensor, and side wall is in 12~15 ° Inclination.

5. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 1, it is characterised in that:

Wherein, in the step 3, photoetching process forms graphical Ni for electron beam evaporation process and does photoresist exposure mask,

Graphical Ni metal foil mask layer is that the shallow etching process of RIE does exposure mask, and etching depth is not less than 2 μm, and sensitive resistance item is answered Than 0.05~0.15 μm of n-SiC thickness,

Shallow etching gas is SF₆With O₂Gaseous mixture, concentration is followed successively by 80sccm and 20sccm, and etching power used is 150W,

Beam power used in electron beam evaporation is 60KW, and evaporation of metal rate is no more than/ the second.

6. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 1, it is characterised in that:

Wherein, in the step 4, the temperature of thermal oxide is 1100 DEG C~1200 DEG C, and the time is 4~6h, the SiO of formation₂Stop Layer is with a thickness of 3~6 μm.

7. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 1, it is characterised in that:

Wherein, in the step 6, high-temperature annealing process is in N₂Under atmosphere and 950 DEG C at a temperature of rapid thermal annealing 1min.

8. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 1, it is characterised in that:

Wherein, in the step 7, part corresponding with SiC chip of high-temp pressure sensor is equipped with side in encapsulation matrix The base cavity of shape, the side length of the base cavity are greater than the pit side length on sensitive diaphragm, and are less than pad structure and are surrounded The side length in region,

Ag nano-particle material includes: particle diameter≤900nm Ag particle and nano-solder paste, also, Ag particle accounting is 65 ~80wt.%,

Sintering temperature≤300 DEG C of Ag nano-particle material and Pt contact lead-wire.

9. a kind of SiC high-temp pressure sensor of non-leaded package characterized by comprising

SiC chip of high-temp pressure sensor includes: having rectangular embossment structure by the lower part that SiC wafer deep etching is formed Sensitive diaphragm, the p-SiC layer being formed on sensitive diaphragm are formed on p-SiC layers the sensitivity as made of N-shaped epitaxial layer etching and press Item is hindered, the SiO being formed on p-SiC layers and sensitive resistance item₂Barrier layer is formed in SiO₂On barrier layer and it is located at sensitive pressure The contact window above item is hindered, and contacts and formed the figure of electrode and pad structure with sensitive resistance item by contact window The Ni/Ti/Ni/Pt metal layer of change；With

Encapsulation part connects inverted SiC chip of high-temp pressure sensor for encapsulating, includes: encapsulation matrix, in SiC high-temperature high-pressure The Ag nano-particle material deposited at the pad of sensor chip, is formed in encapsulation matrix, for allowing Pt contact lead-wire to wear The fairlead being connected with Ag nano-particle material is crossed, is filled between SiC chip of high-temp pressure sensor and encapsulation matrix Glass melten gel at gap, and the thermocouple hole being formed in encapsulation matrix.

10. the manufacturing method of the SiC high-temp pressure sensor of non-leaded package according to claim 9, it is characterised in that:

Wherein, it is rectangular pit that sensitive diaphragm, which includes: outer edge cross section, and be formed in the middle part of the pit, outer edge it is transversal Face is rectangular embossment structure,

Pit and embossment structure have common symmetrical centre with SiC chip of high-temp pressure sensor, and side wall is in 12~15 ° Inclination,

Rectangular base cavity, the base are equipped with towards the not connected part of SiC chip of high-temp pressure sensor in encapsulation matrix The side length of body cavity is greater than the pit side length on sensitive diaphragm, and is less than the side length in the surrounded region of pad structure,

Ag nano-particle material includes: particle diameter≤900nm Ag particle and nano-solder paste, also, Ag particle accounting is 65 ~80wt.%,

The bonding region gross area is less than four points of static-pressure compensation cell electrode graphics area on SiC chip of high-temp pressure sensor One of.