WO2016066090A1 - 一种基于倒装焊封装的甲烷传感器及其制备方法与应用 - Google Patents

一种基于倒装焊封装的甲烷传感器及其制备方法与应用 Download PDF

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WO2016066090A1
WO2016066090A1 PCT/CN2015/093008 CN2015093008W WO2016066090A1 WO 2016066090 A1 WO2016066090 A1 WO 2016066090A1 CN 2015093008 W CN2015093008 W CN 2015093008W WO 2016066090 A1 WO2016066090 A1 WO 2016066090A1
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monolithic
silicon
layer
fixed end
high temperature
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PCT/CN2015/093008
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English (en)
French (fr)
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马洪宇
丁恩杰
赵小虎
刘晓文
胡延军
赵端
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中国矿业大学
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature

Definitions

  • the invention relates to a methane sensor and a preparation method thereof, in particular to a flip chip package-based methane sensor suitable for use in industrial mineral networking, and a preparation method and application thereof.
  • the object of the present invention is to provide a simple structure, the heating element is parallel to the measuring element, so that the measuring element has a large temperature sensing area for sensing the high temperature of the heating element, and can detect low concentration methane (0 to 4%) with high sensitivity.
  • Methane sensor based on flip-chip package and its preparation method and application.
  • the object of the present invention is based on MEMS processing technology and flip chip packaging technology, as follows:
  • the flip chip package based micro methane sensor comprises a monolithic high temperature heater, a monolithic methane gas detector and Ambient temperature detector
  • the single-chip high-temperature heater comprises: a support A, a heating element, two fixed ends A, two fixed fixed ends, a plurality of electrode lead ends, and a plurality of support ends;
  • the monolithic methane gas detector comprises a support B, a temperature measuring element, two fixed ends B, and a plurality of bonding support ends;
  • the ambient temperature detector comprises two electrode ends and a measuring resistor; the ambient temperature detector is arranged on the support A of the monolithic high temperature heater, or on the support B of the monolithic methane gas detector, or in the single An ambient temperature detector is disposed on the support A of the high temperature heater and the support B of the monolithic methane gas detector;
  • the support A and the support B both comprise a silicon substrate and a buried silicon oxide over the silicon substrate;
  • the fixed end A, the bonding fixed end, the supporting end, the electrode leading end and the electrode end are mutually independent on the buried silicon oxide on the support A; the fixed end A and the electrode end are all processed by the silicon layer And oxygen on the silicon layer
  • the silicon layer is provided with a metal layer on the silicon oxide layer; the silicon layer of the fixed end A and the electrode end is provided with a doped silicon layer, and the metal layer is directly in contact with the doped silicon layer through the window of the silicon oxide layer And forming an ohmic contact;
  • the bonding fixed end, the electrode leading end and the supporting end are both processed by a silicon layer, and a silicon oxide layer is disposed on the silicon layer, and a metal layer is disposed on the silicon oxide layer;
  • the heating element is also made of silicon
  • the layer is processed and provided with a passivation protective layer on the outer surface of the silicon layer; the heating element is provided with a high temperature heating unit, two symmetrically arranged silicon cantilevers; the high temperature heating unit is annular, or
  • the temperature measuring component is provided with a temperature measuring unit, two symmetrically arranged connecting arms, and two symmetrically arranged supporting arms; the temperature measuring unit, the connecting arm, the supporting arm and the fixed end B are sequentially connected; the temperature measuring unit
  • the high-temperature heating unit of the monolithic high-temperature heater has the same structural shape and a slightly larger size; the bonding support end and the fixed end B are mutually independent on the buried silicon oxide on the support B; if in the support B An ambient temperature detector is disposed, and the ambient temperature detector is independent of the fixed end B and the plurality of bonding support ends, and there is no connection on the silicon layer; the bonding support end and the fixed end B are processed by the silicon layer.
  • the doped silicon layer of the fixed end B directly contacts to form an ohmic contact;
  • the temperature measuring element is processed by the silicon layer, and a passivation protective layer is disposed on the outer surface of the silicon layer, and the temperature measuring component suspended in the air is fixed by the fixed end On the buried silicon oxide on the support B, the two fixed ends constitute a test Two terminals of the electrical path of the temperature element;
  • the front side of the monolithic methane gas detector is parallel to the front side of the monolithic high temperature heater, and is aligned and electrically connected by metal bonding of the metal bumps after alignment; the aligned monolithic methane gas detector
  • the projection feature on the monolithic high temperature heater is that the two fixed ends of the monolithic methane gas detector respectively coincide with the two bonded fixed ends of the single piece high temperature heater, and the bonding support end of the single piece methane gas detector
  • the support ends corresponding to the single-piece high-temperature heaters respectively coincide, the center of the temperature measuring unit coincides with the center of the high-temperature heating unit of the single-piece high-temperature heater, and the centers of the two have the same distance to the respective supports; the monolithic methane gas Detector and monolithic high temperature heater After the metal bump is fixed by the metal bump, the distance between the temperature measuring unit and the high temperature heating unit of the single piece high temperature heater ranges from 3 to 200 um; the temperature measuring element of the single piece
  • a method for applying a micro-methane sensor based on a flip-chip package in which a single-chip methane gas detector based on a flip-chip packaged micro-methane sensor is placed in a single-chip high-temperature heating of a micro-methane sensor based on a flip-chip package Below the device, a weak current is applied to the monolithic methane gas detector and the ambient temperature detector to prevent the temperature measuring component from reacting with the measuring resistor; and when the single-chip high-temperature heater is energized, the heating element is heated to above 500 °C.
  • the high temperature causes the heating element to enter the working area on the left side of the turning point in its current-resistance characteristic curve, which is the maximum point of resistance that occurs when the resistance increases with current or voltage.
  • the resistance is no longer Continue to increase but decrease; power consumption is about 100mW;
  • the temperature measuring element of the monolithic methane gas detector is affected by the heating high temperature of the heating element, and the temperature increases, and the resistance increases; and when methane gas appears
  • concentration is increased, the temperature of the heating element is lowered, and the temperature of the temperature measuring element is also lowered, resulting in a decrease in its own resistance. It can detect the presence of methane and the methane concentration detected by the electrical method; ambient temperature sensor detecting a temperature on a separate chip microcomputer methane sensor for temperature compensation of the present invention, the methane concentration data.
  • a method for preparing a micro-methane sensor based on a flip-chip package which comprises two preparation methods,
  • a separated monolithic high temperature heater and a separated monolithic methane gas detector are prepared, and the monolithic high temperature heater monolithic methane gas detector is processed by SOI silicon wafer, and a single piece high temperature heater is used.
  • the monolithic methane gas detector can be fabricated on the same SOI wafer or processed on different SOI wafers; then the processed separated monolithic high temperature heater and the separated monolithic methane gas detector are used.
  • the micro-methane sensor of the present invention is prepared by soldering the package into a unitary structure;
  • the first step is to prepare a silicon oxide layer on the SOI silicon wafer
  • the silicon oxide layer on the top layer of silicon is patterned to form a window required for doping or ion implantation
  • doping or ion implantation forms a doped silicon layer
  • the metal is prepared, and the prepared metal is patterned to form a fixed end B, a plurality of bonding support ends, a fixed end A, a bonding fixed end, a support end, a metal layer on the electrode lead end and the electrode end, and a fixed end.
  • A a connecting metal layer between the bonding fixed end and the electrode leading end;
  • lithography forms a pattern of the etch window of the front side structure, and then the RIE dry etching is used to remove the pattern Etching the silicon oxide layer formed in the first step in the window pattern and the silicon layer underneath, etching stops at the buried silicon oxide, forming a heating element on the buried silicon oxide, fixing the end A, bonding the fixed end, and the electrode
  • an etch protection layer is prepared on the front side of the SOI silicon wafer, and a photoresist or PSG (phosphorus silicate glass) is used as an etch protection layer, and the etch protection layer covers the front surface of the entire SOI silicon wafer;
  • a pattern of the back etching window is formed on the back surface of the SOI wafer, and the underlying silicon of the SOI wafer is etched by wet etching or dry etching such as ICP or DRIE, that is, the substrate is etched. Buried silicon oxide;
  • the buried silicon oxide exposed from the substrate is wet-etched by using a hydrofluoric acid solution or a hydrofluoric acid gas mist to release the heating element and the temperature measuring element;
  • the etching protection layer formed in the sixth step is removed;
  • the exposed silicon is oxidized to form a thin silicon oxide layer
  • the front surface of the SOI wafer is covered with a protective layer covering the front portion of the SOI wafer except the heating element, the floating structure of the temperature measuring element, and the measuring resistor of the ambient temperature detector;
  • a protective layer the photoresist can be prepared after precise positioning by using a micro-jet printing device; the photoresist can also be prepared by spraying using a masking plate covering the front surface of the SOI, and the masking plate is exposed except for heating.
  • the measuring element of the component, the floating structure of the temperature measuring element and the measuring resistor of the ambient temperature detector, the remaining part of the SOI wafer is blocked by the masking plate;
  • the ALD atomic layer deposition method is used to prepare yttrium oxide on the outer surface of the measuring element of the heating element, the temperature measuring element suspended structure and the ambient temperature detector, or to prepare an aluminum oxide film, or to prepare a yttrium oxide/alumina composite film. Or preparing a silicon oxide/yttria/alumina composite film, and forming a passivation protective layer together with the thin silicon oxide layer formed in the tenth step;
  • the protective layer prepared in the eleventh step is removed and dried;
  • a plurality of discrete monolithic high temperature heaters and discrete monolithic methane gas detectors are obtained after dicing and cleavage;
  • the front side of the prepared single-piece high-temperature heater is aligned with the front surface of the monolithic methane gas detector, and then the metal of the single-piece high-temperature heater is bonded to the fixed end and the metal layer of the support end.
  • the micro-methane sensor of the present invention is formed in the form of a laminated structure in which the bump is in contact with the fixed end B on the corresponding monolithic methane gas detector, the metal on the bonding support end, and is pressurized and heated to bond;
  • the preparation method (2) is to prepare the micro-methane sensor according to claim 1 for the wafer-level flip-chip package, the monolithic high-temperature heater is processed on one SOI silicon wafer, and the monolithic methane gas detector is circled in another SOI silicon. On-chip processing; then the micro-methane sensor of the invention was prepared using a wafer-level flip-chip package.
  • the preparation method (2) specific steps are:
  • the first step is to prepare a silicon oxide layer on the SOI silicon wafer
  • the silicon oxide layer on the top layer of silicon is patterned to form a window required for doping or ion implantation
  • doping or ion implantation forms a doped silicon layer
  • the metal is prepared, and the prepared metal is respectively formed into a fixed end B, a plurality of bonding support ends, a fixed end A, a bonding fixed end, a support end, a metal lead on the electrode lead end and the electrode end, and a fixing a metal layer connecting the end A, the bonding fixed end and the electrode leading end;
  • lithography forms a pattern of the etch window of the front side structure, and then the RIE dry etching is used to remove the silicon oxide layer formed in the first step of the etch window pattern and the underlying silicon layer, and the etching stops.
  • a heating element In the buried silicon oxide, a heating element, a fixed end A, a bonding fixed end, an electrode lead end, a plurality of supporting ends, a measuring component, a temperature measuring component, a fixed end B, a bonding support end and a heating support are formed on the buried silicon oxide.
  • an etch protection layer is prepared on the front side of the SOI silicon wafer, and a photoresist or PSG (phosphorus silicate glass) is used as an etch protection layer, and the etch protection layer covers the front surface of the entire SOI silicon wafer;
  • an etched window pattern of the back dicing groove is formed on the back surface of the SOI silicon wafer, and the silicon oxide and the underlying silicon on the back surface of the SOI silicon wafer are etched by RIE to form a scribe groove;
  • a back etch window pattern is formed on the back side of the SOI wafer, and the underlying silicon of the SOI wafer is etched by dry etching or dry etching such as ICP or DRIE, that is, the substrate is etched. Buried silicon oxide, releasing heating elements and temperature measuring elements;
  • the buried silicon oxide exposed from the substrate is wet-etched by hydrofluoric acid solution or hydrofluoric acid gas mist to release the heating element and the temperature measuring element;
  • the etching protection layer formed in the sixth step is removed;
  • the exposed silicon is oxidized to form a thin silicon oxide layer
  • the front surface of the SOI silicon wafer is covered by a protective layer covering the front part of the SOI silicon wafer except the heating element, the floating structure of the temperature measuring element and the measuring resistance of the ambient temperature detector;
  • a protective layer As a protective layer; the photoresist can be prepared after precise positioning by using a micro-jet printing device; the photoresist can also be prepared by spraying using a masking plate covering the front surface of the SOI, and the masking plate is exposed except for heating.
  • the component 103, the floating structure of the temperature measuring component 203, and the measuring resistor 1032 of the ambient temperature detector 3, the remaining portions of the SOI silicon wafer are blocked by the masking plate;
  • the thirteenth step using ALD atomic layer deposition method in the thermal element, the temperature measuring element suspended structure and the ambient temperature
  • the outer surface of the measuring resistor is used to prepare yttrium oxide, or to prepare an aluminum oxide film, or to prepare a yttria/alumina composite film, or to prepare a silicon oxide/yttria/alumina composite film, which is thinner than the eleventh step.
  • the silicon oxide layers together form a passivation protective layer;
  • the protective layer prepared in the twelfth step is removed and dried;
  • the first step to the fourteenth step are the processing steps of the monolithic high temperature heater and the monolithic methane gas detector on the respective SOI silicon wafers;
  • the front side of the silicon wafer prepared with the monolithic high temperature heater is aligned with the front surface of the silicon wafer prepared with the monolithic methane gas detector, and then the bonding of the monolithic high temperature heater is performed.
  • the metal bumps on the metal layers of the fixed end and the support end are in contact with the fixed end B of the corresponding single-piece methane gas detector, a plurality of bonding support ends, and are pressed and heated to form a silicon circle containing a single-piece high-temperature heater.
  • the dicing groove on the back surface of the SOI silicon wafer on which the monolithic methane gas detector is prepared is diced, and the dicing groove dicing depth of the dicing groove in this step is only one SOI.
  • the thickness of the silicon wafer is removed, and the cut silicon on the SOI silicon wafer prepared with the monolithic methane gas detector is removed to expose the electrode terminal on the monolithic high temperature heater;
  • the dicing groove on the back surface of the SOI silicon wafer having the single-piece high-temperature heater is diced along the seventh step; the dicing groove dicing depth along the step is two SOI The thickness of the silicon wafer; after the cleavage, the micro-methane sensor based on the flip-chip package of the present invention is obtained.
  • the micro-methane sensor of the present invention firstly uses a MEMS process to process a single-piece high-temperature heater, a monolithic methane gas detector and an ambient temperature detector using a SOI silicon wafer as a substrate, and then obtains a flip-chip package method.
  • the invention discloses a micro-methane sensor based on flip-chip package, which adopts the above scheme and has the following effective effects:
  • the methane sensor of the present invention can realize detection of low concentration methane gas without using a catalyst, using a monolithic high temperature heater and a monolithic methane gas detector; meanwhile, the methane sensor of the present invention does not require oxygen to participate in the detection of methane, so Not affected by oxygen in the air;
  • the temperature measuring element of the monolithic methane gas detector of the present invention has the same shape as the heating element of the monolithic high temperature heater, and the monolithic methane gas detector of the present invention is made to face each other in parallel by the lamination form.
  • the temperature measuring element has a larger heating area, and the monolithic integration of the independent high temperature heating unit and the independent temperature detector cannot achieve a large heat sensitive area of the temperature detector of the present invention, thus making the monolithic methane of the present invention
  • the temperature measuring element of the gas detector can more effectively and independently sense the temperature change information of the high temperature heating unit; the above factors all make The methane sensor of the invention has higher sensitivity;
  • the methane sensor of the present invention does not contain a catalyst and a catalytic carrier. Therefore, the performance of the sensor is not affected by the catalyst, and there is no problem of sensitivity reduction, poisoning, activation, etc. caused by a decrease in catalyst activity;
  • the silicon heater of the methane sensor of the present invention and the temperature measuring component of the monolithic methane gas detector are suspended in the air and away from the respective supports, and the distance is greater than 300 um, and the silicon heater can be driven at a lower electric power.
  • the heating element of the monolithic high temperature heater of the present invention is independent of the temperature measuring elements of the monolithic methane gas detector, without direct contact, ie, does not exist
  • the solid medium is connected so that there is no energy loss in the form of heat conduction from the heating element to the temperature measuring element, thereby effectively reducing the power consumption when the heating element of the monolithic high temperature heater is heated to the operating state; and, the methane sensor of the present invention
  • the power consumption of the methane gas detector and the ambient temperature detector are extremely low; and, when in use, the monolithic methane gas detector Monolithic temperature below the heater, which also helps to reduce the power consumption of the heating element of
  • the heating element of the single-chip high-temperature heater of the invention, the temperature measuring component of the monolithic methane gas detector, and the measuring resistor of the ambient temperature detector are all silicon materials, so that the processing process is uniform, simple, and low in cost;
  • the heating element of the monolithic high temperature heater of the present invention and the temperature measuring component of the monolithic methane gas detector are all obtained by processing single crystal silicon with stable performance, which makes the methane sensor of the invention have good performance under high temperature working condition. Stability and long life; this is because monocrystalline silicon does not have the disadvantages of metal, such as platinum and tungsten, which are easily volatilized and migrated at a temperature higher than 500 degrees Celsius, and there is no possibility that the polycrystalline silicon resistor is easily changed at high temperature.
  • the heating element of the monolithic high-temperature heater of the present invention, the temperature measuring element of the monolithic methane gas detector, and the passivation layer provided on the outer surface of the measuring resistor of the ambient temperature detector also reduce the outside The influence of the environment on the above components, thereby further improving the stability of the performance of the methane sensor of the present invention;
  • the heating element of the monolithic high temperature heater of the micro methane sensor of the invention, the temperature measuring component of the monolithic methane gas detector and the ambient temperature detector realize structural independence, and are no longer subject to the heating and measurement of the conventional single component.
  • the limitation of the temperature function multiplexing can separately regulate the heating element and simultaneously detect the temperature measuring element separately, and there is no coupling between the heating and the temperature measurement, so that the heating element and the temperature measuring element can be precisely regulated respectively, which makes the invention
  • the methane sensor can have multiple operating modes and makes the regulation configuration simple and flexible, thereby improving the intelligence level and sensing performance of the methane sensor;
  • the ambient temperature detector of the present invention is for independently detecting the ambient temperature, which is the methane detection of the present invention. It provides the closest and most realistic temperature data to the heating element and temperature measuring element, which is beneficial to the improvement of temperature compensation characteristics and also provides a good foundation for the intelligentization of methane sensors.
  • the methane sensor of the invention is processed by a MEMS process, and the small size not only makes the sensor consume low power, but also has a fast response speed of up to 40 ms; and the methane concentration is detected by a monolithic methane gas detector with low self-heating effect, and the heat is detected. The noise is reduced to increase the sensitivity of the sensor;
  • the methane sensor of the present invention can be mass-produced in a CMOS process, and has good consistency, so that it can be batch-calibrated, thereby further improving sensor performance and reducing the cost of the sensor calibration link;
  • the micro-methane sensor based on flip-chip package of the invention uses only one high-temperature heating element, and the overall power consumption is low; the set temperature-measuring element has a larger heating area, so that the sensitivity is higher; The service life is compatible with the CMOS process.
  • the mass production can reduce the cost and improve the consistency. It is easy to perform temperature compensation. It can be batch-calibrated. It can meet the demand for high-performance methane sensors in the coal mine underground IoT individual equipment. .
  • 1(a) is a schematic view showing the structure of a single-chip high-temperature heater based on a flip-chip package-based micro-methane sensor of the present invention.
  • 1(b) is a schematic view showing the structure of a single-chip methane gas detector of a flip-chip package-based miniature methane sensor of the present invention.
  • Figure 2 is a cross-sectional view taken along line A-A of Figure 1, which is a schematic view showing the structure of the fixed end B of the monolithic methane gas detector.
  • Fig. 3 is a schematic view showing the structure of a high-temperature heating unit of a monolithic high-temperature heater of the present invention in which a plurality of heating bars are connected in parallel.
  • FIG. 4 is a schematic view showing the sequence of flip chip bonding of a micro-methane sensor based on flip-chip package according to the present invention.
  • Fig. 5 is a schematic view showing the placement of the micro-methane sensor based on the flip chip package of the present invention.
  • Figure 6 is a graph showing the current-resistance characteristic of a heating element of a monolithic high temperature heater of the present invention.
  • the micro-methane sensor includes the illustrated monolithic high temperature heater, a monolithic methane gas detector, and an ambient temperature detector;
  • the monolithic high temperature heater 1 includes: a support A 101, a heating element 103, two fixed ends A 102, two bonding fixed ends A106, a plurality of electrode lead ends 104, a plurality of support ends 105;
  • the monolithic methane gas detector 2 includes a support B 201, a temperature measuring element 203, two fixed ends B 202, and a plurality of bonding support ends 204;
  • the ambient temperature detector 3 includes two electrode terminals 1041 and a measuring resistor 32; the ambient temperature detector 3 is disposed on the holder A 101 of the monolithic high temperature heater 1, or a branch of the monolithic methane gas detector 2 a temperature detector 3 is disposed on the seat B 201, or on the support A 101 of the single-chip high-temperature heater 1 and the support B 201 of the monolithic methane gas detector 2;
  • the holder A 101 and the holder B 201 both include a silicon substrate 11 and a buried silicon oxide 12 over the silicon substrate 11;
  • the fixed end A 102, the bonding fixed end A106, the supporting end 105, the electrode lead end 104 and the electrode end 1041 are mutually independent on the buried silicon oxide 12 on the support A 101; the fixed end A 102 and the electric
  • the extreme layers 1041 are each formed by the silicon layer 21, and a silicon oxide layer 23 is disposed on the silicon layer 21, a metal layer 22 is disposed on the silicon oxide layer 23, and the silicon layer 21 of the fixed end A 102 and the electrode end 1041 is provided.
  • a doped silicon layer 24 is disposed therein, and the metal layer 22 is directly in contact with the doped silicon layer 24 through the window of the silicon oxide layer 23 to form an ohmic contact; the bonding fixed end A106, the electrode lead end 104 and the support end 105 are both
  • the silicon layer 21 is processed, and a silicon oxide layer 23 is disposed on the silicon layer 21, and a metal layer 22 is disposed on the silicon oxide layer 23.
  • the heating element 103 is also processed by the silicon layer 21, and is formed on the silicon layer 21.
  • the outer surface is provided with a passivation protective layer 25; the heating element 103 is provided with a high temperature heating unit 1031, two symmetrically disposed silicon cantilevers 1032; the high temperature heating unit 1031 is annular, or as shown in FIG.
  • each fixed end A106, fixed end A 102 is connected to one end of a corresponding electrode terminal 104, in particular, the metal layer 22 is connected; the electrode terminal 104 is away from the fixed end A 102 and the bonding fixed end A106, and the distance between them should be a single piece of methane gas.
  • the electrode lead-out end 104 and the electrode end 1041 are not blocked by the monolithic methane gas detector 2, and the lead-out end 104 and the electrode end 1041 can be externally leaded.
  • Bonding; a metal bumps 50 having the same height are disposed on the metal layer 22 of the bonding fixed end A106 and the supporting end 105; the two bonding fixed ends A106 are arranged side by side with the two fixed ends A 102, and the arrangement order is a bonding fixed end A106, a fixed end A102, another fixed end A 102, another bonding fixed end A106;
  • the temperature measuring element 203 is provided with a temperature measuring unit 2031, two symmetrically disposed connecting arms 2033, and two symmetrically disposed supporting arms 2032; the temperature measuring unit 2031, the connecting arm 2033, and the supporting arm 2032, the fixed end B 202 is connected in sequence; the temperature measuring unit 2031 and the high temperature heating unit 1031 of the monolithic high temperature heater 1 have the same structural shape and a slightly larger size; the bonding support end 204 and the fixed end B 202 are independent of each other.
  • the bonding support end 204 and the fixed end B 202 are all processed by the silicon layer 21, and each includes a silicon layer 21, a silicon oxide layer 23 disposed outside the silicon layer 21, A metal layer 22 is disposed on the silicon oxide layer 23; a doped silicon layer 24 is disposed in the silicon layer 21 of the fixed end B 202, and the metal layer 22 passes through the window of the silicon oxide layer 23 and the doped silicon layer 24 of the fixed end B 202
  • the direct contact constitutes an ohmic contact;
  • the temperature measuring element 203 is processed from the silicon layer 21 and is provided on the outer surface of the silicon layer 21
  • the passivation protective layer 25 the temperature measuring element 203 suspended in the air is fixed on the buried silicon oxide 12 on the support B 201 through the fixed end B
  • the front side of the monolithic methane gas detector 2 is parallel to the front surface of the monolithic high temperature heater 1, and is aligned and electrically connected by metal bonding of the metal bumps 500; the aligned monolithic methane
  • the projection feature of the gas detector 2 on the monolithic high temperature heater 1 is that the two fixed ends B 202 of the monolithic methane gas detector 2 coincide with the two bonding fixed ends A106 of the single piece high temperature heater 1, respectively.
  • the bonding support end 204 of the sheet methane gas detector 2 coincides with the support end 105 corresponding to the single piece high temperature heater 1, respectively, and the center of the temperature measuring unit 2031 coincides with the center of the high temperature heating unit 1031 of the single piece high temperature heater 1,
  • the center of the person has the same distance to the respective support; the monolithic methane gas detector 2 and the monolithic high temperature heater 1 are fixed by metal bonding of the metal bumps 500, and the temperature measuring unit 2031 and the single piece high temperature heater 1 are The distance between the high temperature heating unit 1031 ranges from 3 to 200 um; the temperature measuring element 203 of the monolithic methane gas detector 2 passes through two fixed ends B 202, two bonding fixed ends A106 of the single piece high temperature heater 1 and Metal bump 500, with key
  • the two electrode terminals 104 connected to the fixed end A106 form a two-terminal device on the monolithic high temperature heater 1, and the wire bonds are carried out on the two electrode terminals 104 connected to the bonding fixed end A106
  • a method of applying a miniature methane sensor based on a flip-chip package, as shown in FIG. 5, is such that the monolithic methane gas detector 2 is positioned below the monolithic high temperature heater 1. Passing the monolithic methane gas detector 2 and the ambient temperature detector 3 with a weak current does not cause the temperature measuring element 203 and the measuring resistor 32 to generate heat; and when the single-chip high temperature heater 1 is energized, the heating element 103 is heated to 500 ° C or higher. The high temperature causes the heating element 103 to operate in the working area to the left of the turning point in the current-resistance characteristic curve as shown in FIG.
  • the resistance does not continue to increase but decreases; the power consumption of the heating element 103 is about 100 mW; when there is no methane gas, the temperature measuring element 203 of the monolithic methane gas detector 2 is heated by the heating element 103.
  • a method for preparing a micro-methane sensor based on a flip-chip package includes two preparation methods:
  • a separated monolithic high temperature heater 1 and a separated monolithic methane gas detector 2 are prepared, and the monolithic high temperature heater 1 monolithic methane gas detector 2 is processed by SOI silicon wafer, single piece
  • the high temperature heater 1 and the monolithic methane gas detector 2 can be processed on the same SOI wafer or processed on different SOI wafers; then the processed separated monolithic high temperature heater 1 and the separated single
  • the sheet methane gas detector 2 is prepared by flip chip bonding to prepare the micromethane sensor of the present invention in a unitary structure.
  • the first step preparing a silicon oxide layer 23 on the SOI silicon wafer
  • the silicon oxide layer 23 on the top layer of silicon is patterned to form a window required for doping or ion implantation
  • the third step doping or ion implantation to form a doped silicon layer 24;
  • the metal is prepared, and the prepared metal is patterned to form a fixed end B 202, a plurality of bonding support ends 204, a fixed end A 102, a bonding fixed end A106, a support end 105, an electrode lead end 104 and an electrode end. a metal layer 22 of 1041 and a connecting metal layer between the fixed end A 102, the bonding fixed end A106 and the electrode lead end 104;
  • a pattern of an etched window of the front surface structure is formed by photolithography, and then the silicon oxide layer 23 and the underlying silicon layer 21 formed in the first step are etched by RIE dry etching, and the etching stops at the buried silicon oxide 12,
  • a heating element 103, a fixed end A 102, a bonding fixed end A106, an electrode lead end 104, a plurality of supporting ends 105, a measuring element 102, a temperature measuring element 203, a fixed end B 202, and a bonding are formed on the buried silicon oxide 12.
  • Support end 204 and ambient temperature detection The structure of the device 3 and the dicing groove;
  • an etch protection layer is prepared on the front side of the SOI silicon wafer, and a photoresist or PSG (phosphorus silicate glass) is used as an etch protection layer, and the etch protection layer covers the front surface of the entire SOI silicon wafer;
  • a pattern of the back etching window is formed by photolithography on the back side of the SOI wafer, using wet etching or ICP (Inductively Coupled Plasma) or DRI (Deep Reactive Ion Etching). Etching and other dry etching method to etch the underlying silicon of the SOI silicon wafer, that is, the substrate 11, the etching stops at the buried silicon oxide 12;
  • ICP Inductively Coupled Plasma
  • DRI Deep Reactive Ion Etching
  • the eighth step using a hydrofluoric acid solution or hydrofluoric acid aerosol wet etching of the buried silicon oxide 12 exposed from the substrate 11, releasing the heating element 103, the temperature measuring element 203;
  • the etch protection layer formed in the seventh step is removed;
  • the exposed silicon is oxidized to form a thin silicon oxide layer
  • the front surface of the SOI wafer is covered with a protective layer covering the front portion of the SOI wafer except the heating element 103, the floating structure of the temperature measuring element 203, and the measuring resistor 1032 of the ambient temperature detector 3;
  • a photoresist as a protective layer; the photoresist can be prepared by precise positioning after using a micro-jet printing device; the photoresist can also be prepared by spraying using a masking plate covering the front surface of the SOI. The plate exposes the measuring resistor 1032 except the heating element 103, the temperature measuring element 203 floating structure and the ambient temperature detector 3, while the remaining SOI silicon wafer front portion is blocked by the masking plate;
  • arsenic oxide is prepared on the outer surface of the heating element 103, the floating structure of the temperature measuring element 203, and the measuring resistor 1032 of the ambient temperature detector 3 by an ALD (Atomic Layer Deposition) method, or an aluminum oxide film is prepared, or an oxidation is prepared.
  • ALD Atomic Layer Deposition
  • a ruthenium/alumina composite film, or a silicon oxide/yttria/alumina composite film, and a thin silicon oxide layer formed in the eleventh step together to form a passivation protective layer 25;
  • the protective layer prepared in the twelfth step is removed and dried;
  • the front side of the prepared monolithic high temperature heater 1 is aligned with the front surface of the monolithic methane gas detector 2 (from a to b); then the single piece is heated at a high temperature.
  • the bonding fixed end A106 of the device 1 and the metal bump 500 on the metal layer 22 of the supporting end 105 are in contact with the metal on the fixed end B 202 of the corresponding monolithic methane gas detector 2 and the bonding support end 204.
  • the micromethane sensor of the present invention (from b to c) as shown in Fig. 5 in the form of a laminated structure in which the pressure is applied and the temperature is increased is bonded.
  • the preparation method (2) preparing the micro-methane sensor according to claim 1 for a wafer-level flip-chip package.
  • the monolithic high temperature heater 1 was processed on a SOI silicon wafer, and the monolithic methane gas detector 2 was processed on another SOI silicon wafer; the micromethane sensor of the invention was then fabricated using a wafer level flip chip package.
  • the first step preparing a silicon oxide layer 23 on the SOI silicon wafer
  • the silicon oxide layer 23 on the top layer of silicon is patterned to form a window required for doping or ion implantation
  • the third step doping or ion implantation to form a doped silicon layer 24;
  • the metal is prepared, and the prepared metal forms a fixed end B 202, a plurality of bonding support ends 204, a fixed end A 102, a bonding fixed end A106, a support end 105, an electrode lead end 104 and an electrode end. a metal layer 22 on the 1041 and a connecting metal layer between the fixed end A 102, the bonding fixed end A106 and the electrode lead end 104;
  • lithography forms a pattern of the etch window of the front surface structure, and then the RIE dry etching is used to remove the silicon oxide layer 23 formed in the first step of the etch window pattern and the underlying silicon layer 21, engraved
  • the etching stops at the buried silicon oxide 12, and the heating element 103, the fixed end A 102, the bonding fixed end A106, the electrode terminal 104, the plurality of supporting ends 105, the measuring element 102, and the temperature measuring element are formed on the buried silicon oxide 12.
  • an etch protection layer is prepared on the front side of the SOI silicon wafer, and a photoresist or PSG (phosphorus silicate glass) is used as an etch protection layer, and the etch protection layer covers the front surface of the entire SOI silicon wafer;
  • an etched window pattern of the back dicing groove is formed on the back surface of the SOI silicon wafer, and the silicon oxide and the underlying silicon on the back surface of the SOI silicon wafer are etched by RIE to form a scribe groove;
  • a backside etched window pattern is formed on the back side of the SOI wafer, and the underlying silicon of the SOI wafer is etched by dry etching, such as wet etching or ICP or DRIE deep reactive ion etching. 11, the etching stops at the buried silicon oxide 12;
  • the ninth step using a hydrofluoric acid solution or hydrofluoric acid aerosol wet etching of the buried silicon oxide 12 exposed from the substrate 11, releasing the heating element 103, the temperature measuring element 203;
  • the etching protection layer formed in the sixth step is removed;
  • the exposed silicon is oxidized to form a thin silicon oxide layer
  • the front surface of the SOI wafer is covered with a protective layer covering the front portion of the SOI wafer except the heating element 103, the floating structure of the temperature measuring element 203, and the measuring resistor 1032 of the ambient temperature detector 3;
  • a photoresist as a protective layer; the photoresist can be prepared by precise positioning after using a micro-jet printing device; the photoresist can also be prepared by spraying using a masking plate covering the front surface of the SOI. Version The heating element 103, the floating structure of the temperature measuring element 203, and the measuring resistor 1032 of the ambient temperature detector 3 are removed, and the remaining SOI wafer front portion is blocked by the masking plate;
  • the argon oxide is prepared by using the ALD method on the outer surface of the heating element 103, the floating structure of the temperature measuring element 203, and the measuring resistor 1032 of the ambient temperature detector 3, or an aluminum oxide film is prepared, or a cerium oxide/alumina composite is prepared. a film, or a silicon oxide / yttria / alumina composite film, together with the thin layer of silicon oxide formed in the eleventh step to form a passivation protective layer 25;
  • the protective layer prepared in the twelfth step is removed and dried;
  • the first step to the fourteenth step are the processing steps of the monolithic high temperature heater 1 and the monolithic methane gas detector 2 on the respective SOI silicon wafers;
  • the front side of the silicon wafer prepared with the monolithic high temperature heater 1 is aligned with the front surface of the silicon wafer prepared with the monolithic methane gas detector 2, and then the monolithic high temperature heater 1 is
  • the bonding fixed end A106 and the metal bumps 500 on the metal layer 22 of the supporting end 105 are in contact with the fixed end B 202 of the corresponding monolithic methane gas detector 2, the plurality of bonding support ends 204, and applying pressure and temperature increasing keys.
  • the dicing groove on the back surface of the SOI silicon wafer on which the monolithic methane gas detector 2 is prepared is diced, and the dicing groove dicing depth of the dicing groove along the step is only one.
  • the thickness of the SOI silicon wafer is removed, and the cut silicon on the SOI silicon wafer prepared with the monolithic methane gas detector 2 is removed to expose the electrode terminal 104 on the monolithic high temperature heater 1;
  • the dicing groove on the back surface of the SOI silicon wafer on which the monolithic high temperature heater 1 is prepared is diced along the seventh step; the dicing groove dicing depth along the step is two The thickness of the SOI silicon wafer; the lobes obtain the micro-methane sensor based on the flip-chip package of the present invention.

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Abstract

一种基于倒装焊封装的微型甲烷传感器及其制备方法。该甲烷传感器首先采用MEMS技术加工制备单片高温加热器（1）与单片甲烷气体检测器（2）与环境温度检测器（3），然后通过倒装焊封装技术将单片高温加热器（1）与单片甲烷气体检测器（2）形成一个整体的叠层结构形式的微型甲烷传感器。其中的单片高温加热器（1）独立加热至500℃以上高温；单片甲烷气体检测器（2）独立检测因甲烷出现及浓度变化造成的温度下降，其测量电路与单片高温加热器（1）的电路相互独立，互不影响。该传感器的制备工艺与CMOS工艺兼容，功耗低、灵敏度高、使用寿命长。

Description

一种基于倒装焊封装的甲烷传感器及其制备方法与应用 技术领域
本发明涉及一种甲烷传感器及其制备方法，特别是一种适用于工矿物联网中使用的基于倒装焊封装的甲烷传感器及其制备方法与应用。
背景技术
随着物联网的发展，当前的甲烷传感器无法满足单兵装备对低功耗、长寿命、低成本的检测低浓度甲烷的甲烷传感器的需求。目前用于煤矿井下检测低浓度甲烷的仍是基于传统铂丝加热的催化燃烧式甲烷传感器，其功耗较大，尤其是催化剂的使用导致甲烷检测性能不稳定、校验时间短等缺点；而红外甲烷传感器价格高、传感元件受粉尘与水汽严重影响；这两种甲烷传感器都不能很好的满足物联网对低功耗甲烷传感器的应用需求。而其它的甲烷传感器亦无法适应煤矿井下高湿度的环境。
发明内容
本发明的目的是要提供一种结构简单，加热元件与测量元件平行相对，使测量元件具有大的感受加热元件高温的感温面积，能高灵敏度的检测低浓度甲烷(0～4％)的基于倒装焊封装的甲烷传感器及其制备方法与应用。
针对上述技术目的，本发明的目的是基于MEMS加工技术与倒装焊封装技术实现的，具体如下：该基于倒装焊封装的微型甲烷传感器包括单片高温加热器、单片甲烷气体检测器和环境温度检测器；
所述单片高温加热器包括：支座A、加热元件、2个固定端A、2个键合固定端、多个电极引出端、多个支撑端；
所述单片甲烷气体检测器包括支座B、测温元件、2个固定端B、若干键合支撑端；
所述环境温度检测器包括两个电极端及测量电阻；所述环境温度检测器设在单片高温加热器的支座A上，或单片甲烷气体检测器的支座B上，或在单片高温加热器的支座A与单片甲烷气体检测器的支座B上都设置有环境温度检测器；
所述支座A与支座B都包括硅衬底与硅衬底之上的埋层氧化硅；
所述固定端A、键合固定端、支撑端、电极引出端与电极端均相互独立的设在支座A上的埋层氧化硅上；固定端A及电极端均由硅层加工而成，并在硅层上设有氧 化硅层、在氧化硅层上设有金属层；所述固定端A及电极端的硅层内均设有掺杂硅层，金属层均通过氧化硅层的窗口与掺杂硅层直接接触并构成欧姆接触；键合固定端、电极引出端与支撑端均由硅层加工而成，并在硅层上设有氧化硅层，在氧化硅层上设有金属层；加热元件同样由硅层加工而成，并在硅层的外表面设有钝化保护层；所述加热元件设有高温加热单元、两个对称设置的硅悬臂；所述高温加热单元为圆环状，或多个加热条的并联；所述硅悬臂的长度大于300um；所述单个的硅悬臂的一端与高温加热单元相连，另一端与支座A上的一个固定端A相连；电极引出端也设在支座A的埋层氧化硅上；每个键合固定端、固定端A均与一个对应的电极引出端的一端相连，尤其是金属层是相连接的；电极引出端远离固定端A和键合固定端，其间距离应使单片甲烷气体检测器倒装焊在单片高温加热单元上之后，电极引出端与电极端不被单片甲烷气体检测器遮挡，在电极引出端和电极端上可以向外进行引线键合；在键合固定端、支撑端的金属层上设有高度相同的金属凸块；2个键合固定端与2个固定端A并排间隔布置，排列顺序分别为一个键合固定端、一个固定端A、另一个固定端A、另一个键合固定端；
所述测温元件设有测温单元、两个对称设置的连接臂，2个对称设置的支撑臂；所述测温单元、连接臂、支撑臂、固定端B依次相连；所述测温单元与单片高温加热器的高温加热单元结构形状相同，尺寸稍大；所述键合支撑端、固定端B均相互独立的设在支座B上的埋层氧化硅上；若在支座B上设有环境温度检测器，则环境温度检测器与固定端B及若干键合支撑端相互独立、不存在硅层上的连接；所述键合支撑端、固定端B均由硅层加工而成，均包括硅层、设在硅层外的氧化硅层、设在氧化硅层上的金属层；固定端B的硅层内设有掺杂硅层，金属层通过氧化硅层的窗口与固定端B的掺杂硅层直接接触构成欧姆接触；测温元件由硅层加工而成，并在硅层的外表面设有钝化保护层，悬在空气中的测温元件通过固定端固定在支座B上的埋层氧化硅上，两个固定端构成测温元件的电通路的两个端子；
单片甲烷气体检测器的正面与单片高温加热器的正面平行相对，对准后通过金属凸点的金属键合实现二者的紧密固定与电连接；对准后的单片甲烷气体检测器在单片高温加热器上的投影特征为：单片甲烷气体检测器的2个固定端分别与单片高温加热器的2个键合固定端重合，单片甲烷气体检测器的键合支撑端分别与单片高温加热器对应的支撑端重合，测温单元的中心与单片高温加热器的高温加热单元的中心重合，二者的中心到各自的支座具有相同的距离；单片甲烷气体检测器与单片高温加热器通 过金属凸点金属键合固定后，测温单元与单片高温加热器的高温加热单元之间的距离范围为3至200um；单片甲烷气体检测器的测温元件通过两个固定端B、单片高温加热器的两个键合固定端及其上的金属凸点、与键合固定端相连接的两个电极引出端在单片高温加热器上构成一个二端子器件，并在所述的与键合固定端相连接的两个电极引出端上进行引线键合可实现与外部电路的连接；
一种基于倒装焊封装的微型甲烷传感器的应用方法，使用时使该基于倒装焊封装的微型甲烷传感器的单片甲烷气体检测器位于基于倒装焊封装的微型甲烷传感器的单片高温加热器上的下方，给单片甲烷气体检测器与环境温度检测器通以微弱电流不使测温元件与测量电阻发热；而给单片高温加热器通电后则使加热元件加热至500℃以上的高温，使加热元件进入其电流-电阻特性曲线中转折点左侧的工作区域，所述转折点为电阻随电流或电压增大而出现的电阻最大点，当电流或电压继续增大时，电阻不再继续增大反而减小；功耗在100mW左右；当没有甲烷气体时，单片甲烷气体检测器的测温元件受加热元件的加热高温影响温度升高，电阻增大；而当甲烷气体出现时及浓度增加时，加热元件的温度降低，测温元件受其影响温度也降低，导致自身电阻的降低，于是通过电学检测的方法可以检测甲烷的出现及甲烷浓度变化；环境温度检测器独立探测本发明微型甲烷传感器的片上温度用于甲烷浓度数据的温度补偿。
基于倒装焊封装的微型甲烷传感器的制备方法，其包括两种制备方法，
制备方法(一)首先制备分离的单片高温加热器与分离的单片甲烷气体检测器，所述的单片高温加热器单片甲烷气体检测器采用SOI硅片加工，单片高温加热器与单片甲烷气体检测器制备时可以在同一SOI硅片上加工，或者在不同的SOI硅片上加工；然后将加工好的分离的单片高温加热器与分离的单片甲烷气体检测器采用倒装焊封装制备成整体结构形式的本发明的微型甲烷传感器；
制备方法(一)的具体制备步骤为：
第一步，在SOI硅片上制备氧化硅层；
第二步，图形化顶层硅之上的氧化硅层，形成掺杂或离子注入所需的窗口；
第三步，掺杂或离子注入形成掺杂硅层；
第四步，制备金属，并图形化所制备的金属形成固定端B、若干键合支撑端、固定端A、键合固定端、支撑端、电极引出端上与电极端的金属层以及固定端A、键合固定端与电极引出端之间的连接金属层；
第五步，光刻形成正面结构的刻蚀窗口的图形，随后采用RIE干法刻蚀去除所述 刻蚀窗口图形中的第一步生成的氧化硅层及其下的硅层，刻蚀停止于埋层氧化硅，在埋层氧化硅上形成加热元件、固定端A、键合固定端、电极引出端、多个支撑端、测量元件、测温元件、固定端B、键合支撑端与环境温度检测器的结构及划片槽；
第六步，在SOI硅片的正面制备刻蚀保护层，采用光刻胶或PSG(磷硅玻璃)作为刻蚀保护层，所述刻蚀保护层覆盖整个SOI硅片的正面；
第七步，在SOI硅片背面光刻形成背面刻蚀窗口的图形，采用湿法刻蚀或ICP或DRIE等干法刻蚀方法刻蚀SOI硅片的底层硅，即衬底，刻蚀停止于埋层氧化硅；
第八步，采用氢氟酸溶液或氢氟酸气雾湿法刻蚀从衬底露出的埋层氧化硅，释放出加热元件、测温元件；
第九步，去除第六步所形成的刻蚀保护层；
第十步，对暴露出的硅进行氧化，形成薄层氧化硅层；
第十一步，采用保护层覆盖SOI硅片的正面，所述保护层覆盖除加热元件、测温元件悬空结构以及环境温度检测器的测量电阻以外的SOI硅片正面部分；可采用光刻胶作为保护层；可采用微喷印设备在精确定位后制备所述光刻胶；也可使用覆盖在SOI的正面的掩蔽版采用喷涂的方法制备所述光刻胶，所述掩蔽版露出除加热元件、测温元件悬空结构以及环境温度检测器的测量电阻，其余的SOI硅片正面部分被掩蔽版遮挡住；
第十二步，采用ALD原子层沉积方法在热元件、测温元件悬空结构以及环境温度检测器的测量电阻的外表面制备氧化铪，或制备氧化铝薄膜，或制备氧化铪/氧化铝复合薄膜，或制备氧化硅/氧化铪/氧化铝复合薄膜，与第十步形成的薄层氧化硅层共同构成钝化保护层；
第十三步，去除第十一步制备的保护层，干燥；
第十四步，划片、裂片后得到数量众多分立的单片高温加热器与分立的单片甲烷气体检测器；
第十五步，将制备好的单片高温加热器的正面与单片甲烷气体检测器的正面贴合对准，随后将单片高温加热器的键合固定端、支撑端的金属层上的金属凸块与对应的单片甲烷气体检测器上的固定端B、键合支撑端上的金属相接触并施加压力、升温进行键合形成整体的叠层结构形式的本发明的微型甲烷传感器；
或制备方法(二)为圆片级倒装焊封装制备权利要求1所述的微型甲烷传感器，单片高温加热器在一个SOI硅圆片上加工，单片甲烷气体检测器在另一个SOI硅圆 片上加工；然后采用圆片级倒装焊封装制备成本发明的微型甲烷传感器。
制备方法(二)具体步骤为：
第一步，在SOI硅片上制备氧化硅层；
第二步，图形化顶层硅之上的氧化硅层，形成掺杂或离子注入所需的窗口；
第三步，掺杂或离子注入形成掺杂硅层；
第四步，制备金属，并图形化所制备的金属分别形成固定端B、若干键合支撑端、固定端A、键合固定端、支撑端、电极引出端与电极端上的金属层以及固定端A、键合固定端与电极引出端之间的连接金属层；
第五步，光刻形成正面结构的刻蚀窗口的图形，随后采用RIE干法刻蚀去除所述刻蚀窗口图形中的第一步生成的氧化硅层及其下的硅层，刻蚀停止于埋层氧化硅，在埋层氧化硅上形成加热元件、固定端A、键合固定端、电极引出端、多个支撑端、测量元件、测温元件、固定端B、键合支撑端与环境温度检测器的结构；
第六步，在SOI硅片的正面制备刻蚀保护层，采用光刻胶或PSG(磷硅玻璃)作为刻蚀保护层，所述刻蚀保护层覆盖整个SOI硅片的正面；
第七步，在SOI硅圆片的背面光刻形成背面划片槽的刻蚀窗口图形，采用RIE刻蚀SOI硅片背面的氧化硅与底层硅，形成划片槽；
第八步，在SOI硅片背面光刻形成背面刻蚀窗口图形，采用湿法刻蚀或ICP或DRIE等干法刻蚀方法刻蚀SOI硅片的底层硅，即衬底，刻蚀停止于埋层氧化硅，释放出加热元件、测温元件；
第九步，采用氢氟酸溶液或氢氟酸气雾湿法刻蚀从衬底露出的埋层氧化硅，释放出加热元件、测温元件；
第十步，去除第六步所形成的刻蚀保护层；
第十一步，对暴露出的硅进行氧化，形成薄层氧化硅层；
第十二步，采用保护层覆盖SOI硅片的正面，所述保护层覆盖除加热元件、测温元件悬空结构以及环境温度检测器的测量电阻以外的SOI硅片正面部分；可采用光刻胶作为保护层；可采用微喷印设备在精确定位后制备所述光刻胶；也可使用覆盖在SOI的正面的掩蔽版采用喷涂的方法制备所述光刻胶，所述掩蔽版露出除加热元件103、测温元件203悬空结构以及环境温度检测器3的测量电阻1032，其余的SOI硅片正面部分被掩蔽版遮挡住；
第十三步，采用ALD原子层沉积方法在热元件、测温元件悬空结构以及环境温 度检测器的测量电阻的外表面制备氧化铪，或制备氧化铝薄膜，或制备氧化铪/氧化铝复合薄膜，或制备氧化硅/氧化铪/氧化铝复合薄膜，与第十一步形成的薄层氧化硅层一起构成钝化保护层；
第十四步，去除第十二步制备的保护层，干燥；
上述第一步至第十四步为单片高温加热器、单片甲烷气体检测器在各自SOI硅圆片上的加工步骤；
第十五步，将制备好有单片高温加热器的硅圆片的正面与制备有单片甲烷气体检测器的硅圆片的正面贴合对准，随后将单片高温加热器的键合固定端、支撑端的金属层上的金属凸块与对应的单片甲烷气体检测器上固定端B、若干键合支撑端接触并施加压力、升温进行键合形成含有单片高温加热器的硅圆片与含有单片甲烷气体检测器的硅圆片为一体的叠层式硅圆片；
第十六步，沿第七步所述在制备有单片甲烷气体检测器的SOI硅圆片背面上的划片槽划片，沿本步骤所述划片槽划片的切割深度只有一个SOI硅圆片的厚度，去除掉所述制备有单片甲烷气体检测器的SOI硅圆片上的切割的硅，露出单片高温加热器上的电极引出端；
第十七步，沿第七步所述在制备有单片高温加热器的SOI硅圆片背面上的划片槽划片；沿本步骤所述划片槽划片的切割深度为两个SOI硅圆片的厚度；裂片后得到本发明的基于倒装焊封装的微型甲烷传感器。
有益效果，本发明的微型甲烷传感器的首先以SOI硅圆片为衬底采用MEMS工艺加工单片高温加热器、单片甲烷气体检测器与境温度检测器，继而采用倒装焊封装方法获得本发明的基于倒装焊封装的微型甲烷传感器，由于采用了上述方案，具有以下有效效果：
1、本发明的甲烷传感器不使用催化剂，使用单片高温加热器与单片甲烷气体检测器便可实现低浓度甲烷气体的检测；同时，本发明的甲烷传感器对甲烷的检测无需氧气参与，因此不受空气中氧气的影响；
2、本发明的单片甲烷气体检测器的测温元件具有与单片高温加热器的加热元件相同的形状，且通过叠层的形式面面平行相对，使本发明的单片甲烷气体检测器的测温元件具有更大的受热面积，而独立的高温加热单元与独立的温度检测器的单片集成方式则无法实现本发明温度检测器大的感热面积，因此使本发明的单片甲烷气体检测器的测温元件能更加有效的独立感受高温加热单元的温度变化信息；上述因素都使得 本发明的甲烷传感器具有更高的灵敏度；
3、本发明的甲烷传感器不含有催化剂与催化载体，因此，传感器的性能不受催化剂的影响，不存在催化剂活性降低导致的灵敏度降低、中毒、激活等问题；
4、本发明的甲烷传感器的硅加热器与单片甲烷气体检测器的测温元件都悬在空气中且远离各自的支座，距离大于300um以上，以较低的电功率即可将硅加热器加热到500℃以上的高温，因此具有功耗低的优势；其次，本发明的单片高温加热器的加热元件与单片甲烷气体检测器的测温元件相互独立，没有直接接触，即不存在固态介质连接，因此不存在从加热元件到测温元件的热传导形式的能量损失，因此有效降低了单片高温加热器的加热元件的加热到工作状态时的功耗；并且，本发明的甲烷传感器仅单片高温加热器的一个加热元件需要加热到高温；单片甲烷气体检测器的测温元件与环境温度检测器都只需极低的电流即可工作，而无需加热至高温，因此单片甲烷气体检测器的测温元件与环境温度检测器的功耗都极低；并且，在使用时，单片甲烷气体检测器位于单片高温加热器的下方，这也有助于降低高温加热器的加热元件的功耗；上述的综合措施使本发明的甲烷传感器的整体功耗得以大幅降低；
5、本发明的单片高温加热器的加热元件、单片甲烷气体检测器的测温元件、环境温度检测器的测量电阻都是硅材料，使得加工工艺统一、简单、成本较低；
6、本发明的单片高温加热器的加热元件、单片甲烷气体检测器的测温元件都是采用性能稳定的单晶硅加工得到，这使本发明的甲烷传感器在高温工作状态下具有良好的稳定性与长的寿命；这是因为单晶硅不存在铂、钨等金属加热材料在500摄氏度以上的高温容易挥发、迁移等缺点、也不存在多晶硅电阻在高温下晶界电阻易于变化、无法掌控的缺点；同时，在本发明的单片高温加热器的加热元件、单片甲烷气体检测器的测温元件及环境温度检测器的测量电阻的外表面设置的钝化层也降低了外界环境对上述元器件的影响，从而进一步提高了本发明的甲烷传感器性能的稳定性；
7、本发明的微型甲烷传感器的单片高温加热器的加热元件、单片甲烷气体检测器的测温元件及环境温度检测器实现了结构上的独立，不再受传统的单一元件加热与测温功能复用的限制，可以单独调控加热元件、同时单独对测温元件进行检测，加热与测温不存在耦合，从而可对加热元件与测温元件分别进行精确的调控，这使本发明的甲烷传感器可具有多种工作模式，且使调控配置简单、灵活，继而提高甲烷传感器的智能化水平及传感性能；
8、本发明的环境温度检测器用于独立检测环境温度，这为本发明的甲烷检测提 供了与加热元件、测温元件距离最近、最真实的温度数据，有利于温度补偿特性的提高、同时也为甲烷传感器智能化提供了良好基础；
9、本发明的甲烷传感器采用MEMS工艺加工，尺寸小不但使传感器功耗低，并且响应速度快，可达40ms左右；由于采用自加热效应低的单片甲烷气体检测器检测甲烷浓度，其热噪声的降低使传感器的灵敏度得到提高；
10、本发明的甲烷传感器可采用CMOS工艺批量生产，可具有良好的一致性，因此还可批量校准，因此能进一步提高传感器性能并降低传感器校准环节的成本；
优点：本发明的一种基于倒装焊封装的微型甲烷传感器，只使用一个高温加热元件，整体功耗低；设置的测温元件具有更大的受热面积，使灵敏度得到更高；具有更长的使用寿命；其制备方法可与CMOS工艺兼容，批量制作可降低成本、并提高一致性；易于进行温度补偿；可批量校准；能够满足煤矿井下环境物联网单兵装备对高性能甲烷传感器的需求。
附图说明
图1(a)为本发明的基于倒装焊封装的微型甲烷传感器的单片高温加热器的结构示意图。
图1(b)为本发明的基于倒装焊封装的微型甲烷传感器的单片甲烷气体检测器的结构示意图。
图2为图1中的A-A截面剖视图，即单片甲烷气体检测器的固定端B的结构示意图。
图3为本发明的单片高温加热器的高温加热单元采用多个加热条并联的结构形式的示意图。
图4为本发明的基于倒装焊封装的微型甲烷传感器的倒装焊封装制的顺序示意图。
图5为使用本发明的基于倒装焊封装的微型甲烷传感器时的放置示意图。
图6本发明的单片高温加热器的加热元件的电流-电阻特性曲线。
图中：1-单片高温加热器，2-单片甲烷气体检测器，3-环境温度检测器，11-硅衬底，12-埋层氧化硅，21-硅层，22-金属层，23-氧化硅层，24-掺杂硅层，25-钝化保护层，101-支座A，102-固定端A，103-加热元件，104-电极引出端，105-支撑端，106-键合固定端A，201-支座B，202-固定端B，203-测温元件，204-键合支撑端B，500- 金属凸点，1031-高温加热单元，1032-硅悬臂，1041-电极端，1041-电极端，2031-测温单元，2032-支撑臂，2033-连接臂。
具体实施方式
下面结合附图对本发明的一个实施例作进一步的描述：
如图1(a)、图1(b)、图2、图3中，该微型甲烷传感器包括所示单片高温加热器、单片甲烷气体检测器和环境温度检测器；
所述单片高温加热器1包括：支座A 101、加热元件103、2个固定端A 102、2个键合固定端A106、多个电极引出端104、多个支撑端105；
所述单片甲烷气体检测器2包括支座B 201、测温元件203、2个固定端B 202、若干键合支撑端204；
所述环境温度检测器3包括两个电极端1041及测量电阻32；所述环境温度检测器3设在单片高温加热器1的支座A 101上，或单片甲烷气体检测器2的支座B 201上，或在单片高温加热器1的支座A 101与单片甲烷气体检测器2的支座B 201上都设置有环境温度检测器3；
所述支座A 101与支座B 201都包括硅衬底11与硅衬底11之上的埋层氧化硅12；
所述固定端A 102、键合固定端A106、支撑端105、电极引出端104与电极端1041均相互独立的设在支座A 101上的埋层氧化硅12上；固定端A 102及电极端1041均由硅层21加工而成，并在硅层21上设有氧化硅层23、在氧化硅层23上设有金属层22；所述固定端A 102及电极端1041的硅层21内均设有掺杂硅层24，金属层22均通过氧化硅层23的窗口与掺杂硅层24直接接触并构成欧姆接触；键合固定端A106、电极引出端104与支撑端105均由硅层21加工而成，并在硅层21上设有氧化硅层23，在氧化硅层23上设有金属层22；加热元件103同样由硅层21加工而成，并在硅层21的外表面设有钝化保护层25；所述加热元件103设有高温加热单元1031、两个对称设置的硅悬臂1032；所述高温加热单元1031为圆环状，或为如图3所示多个加热条1013的并联；所述硅悬臂1032的长度大于300um；所述单个的硅悬臂1032的一端与高温加热单元1031相连，另一端与支座A101上的一个固定端A102相连；电极引出端104也设在支座A 101的埋层氧化硅12上；每个键合固定端A106、固定端A 102均与一个对应的电极引出端104的一端相连，尤其是金属层22是相连接的；电极引出端104远离固定端A 102和键合固定端A106，其间距离应使单片甲烷气体 检测器2倒装焊在单片高温加热单元上1之后，电极引出端104与电极端1041不被单片甲烷气体检测器2遮挡，在电极引出端104和电极端1041上可以向外进行引线键合；在键合固定端A106、支撑端105的金属层22上设有高度相同的金属凸块500；2个键合固定端A106与2个固定端A 102并排间隔布置，排列顺序分别为一个键合固定端A106、一个固定端A102、另一个固定端A 102、另一个键合固定端A106；
如图1(b)所述测温元件203设有测温单元2031、两个对称设置的连接臂2033，2个对称设置的支撑臂2032；所述测温单元2031、连接臂2033、支撑臂2032、固定端B 202依次相连；所述测温单元2031与单片高温加热器1的高温加热单元1031结构形状相同，尺寸稍大；所述键合支撑端204、固定端B 202均相互独立的设在支座B 201上的埋层氧化硅12上；若在支座B 201上设有环境温度检测器3，则环境温度检测器3与固定端B 202及若干键合支撑端204相互独立、不存在硅层21上的连接；所述键合支撑端204、固定端B 202均由硅层21加工而成，均包括硅层21、设在硅层21外的氧化硅层23、设在氧化硅层23上的金属层22；固定端B 202的硅层21内设有掺杂硅层24，金属层22通过氧化硅层23的窗口与固定端B 202的掺杂硅层24直接接触构成欧姆接触；测温元件203由硅层21加工而成，并在硅层21的外表面设有钝化保护层25，悬在空气中的测温元件203通过固定端B 202固定在支座B 201上的埋层氧化硅12上，两个固定端B 202构成测温元件203的电通路的两个端子；
单片甲烷气体检测器2的正面与单片高温加热器1的正面平行相对，对准后通过金属凸点500的金属键合实现二者的紧密固定与电连接；对准后的单片甲烷气体检测器2在单片高温加热器1上的投影特征为：单片甲烷气体检测器2的2个固定端B 202分别与单片高温加热器1的2个键合固定端A106重合，单片甲烷气体检测器2的键合支撑端204分别与单片高温加热器1对应的支撑端105重合，测温单元2031的中心与单片高温加热器1的高温加热单元1031的中心重合，二者的中心到各自的支座具有相同的距离；单片甲烷气体检测器2与单片高温加热器1通过金属凸点500金属键合固定后，测温单元2031与单片高温加热器1的高温加热单元1031之间的距离范围为3至200um；单片甲烷气体检测器2的测温元件203通过两个固定端B 202、单片高温加热器1的两个键合固定端A106及其上的金属凸点500、与键合固定端A106相连接的两个电极引出端104在单片高温加热器1上构成一个二端子器件，在所述的与键合固定端A106相连接的两个电极引出端104上进行引线键合可实现与外部电路的连接。
一种基于倒装焊封装的微型甲烷传感器的应用方法，使用时如图5所示，使单片甲烷气体检测器2位于单片高温加热器上1的下方。给单片甲烷气体检测器2与环境温度检测器3通以微弱电流不使测温元件203与测量电阻32发热；而给单片高温加热器1通电后则使加热元件103加热至500℃以上的高温，使加热元件103工作在如图6所示的电流-电阻特性曲线中转折点左侧的工作区域，所述转折点为电阻随电流或电压增大而出现的电阻最大点，当电流或电压继续增大时，电阻不再继续增大反而减小；加热元件103的功耗在100mW左右；当没有甲烷气体时，单片甲烷气体检测器2的测温元件203受加热元件103的加热高温影响温度升高，电阻增大；而当甲烷气体出现时及浓度增加时，加热元件103的温度降低，测温元件203受其影响温度也降低，导致自身电阻的降低，于是通过电学检测的方法可以检测甲烷的出现及甲烷浓度变化；环境温度检测器3独立探测本发明微型甲烷传感器的片上温度用于甲烷浓度数据的温度补偿。
基于倒装焊封装的微型甲烷传感器的制备方法，包括两种制备方法:
制备方法(一)首先制备分离的单片高温加热器1与分离的单片甲烷气体检测器2，所述的单片高温加热器1单片甲烷气体检测器2采用SOI硅片加工，单片高温加热器1与单片甲烷气体检测器2制备时可以在同一SOI硅片上加工，或者在不同的SOI硅片上加工；然后将加工好的分离的单片高温加热器1与分离的单片甲烷气体检测器2采用倒装焊封装制备成整体结构形式的本发明的微型甲烷传感器。
制备方法(一)的具体制备步骤为：
第一步，在SOI硅片上制备氧化硅层23；
第二步，图形化顶层硅之上的氧化硅层23，形成掺杂或离子注入所需的窗口；
第三步，掺杂或离子注入形成掺杂硅层24；
第四步，制备金属，并图形化所制备的金属形成固定端B 202、若干键合支撑端204、固定端A 102、键合固定端A106、支撑端105、电极引出端104上与电极端1041的金属层22以及固定端A 102、键合固定端A106与电极引出端104之间的连接金属层；
第五步，光刻形成正面结构的刻蚀窗口的图形，随后采用RIE干法刻蚀第一步生成的氧化硅层23及其下的硅层21，刻蚀停止于埋层氧化硅12，在埋层氧化硅12上形成加热元件103、固定端A 102、键合固定端A106、电极引出端104、多个支撑端105、测量元件102、测温元件203、固定端B 202、键合支撑端204与环境温度检测 器3的结构及划片槽；
第六步，在SOI硅片的正面制备刻蚀保护层，采用光刻胶或PSG(磷硅玻璃)作为刻蚀保护层，所述刻蚀保护层覆盖整个SOI硅片的正面；
第七步，在SOI硅片背面光刻形成背面刻蚀窗口的图形，采用湿法刻蚀或ICP(Inductively Coupled Plasma，感应耦合等离子体刻蚀)或DRI(Deep Reactive Ion Etching，深反应离子刻蚀)等干法刻蚀方法刻蚀SOI硅片的底层硅，即衬底11，刻蚀停止于埋层氧化硅12；
第八步，采用氢氟酸溶液或氢氟酸气雾湿法刻蚀从衬底11露出的埋层氧化硅12，释放出加热元件103、测温元件203；
第九步，去除第七步所形成的刻蚀保护层；
第十步，对暴露出的硅进行氧化，形成薄层氧化硅层；
第十一步，采用保护层覆盖SOI硅片的正面，所述保护层覆盖除加热元件103、测温元件203悬空结构以及环境温度检测器3的测量电阻1032以外的SOI硅片正面部分；可采用光刻胶作为保护层；可采用微喷印设备在精确定位后制备所述光刻胶；也可使用覆盖在SOI的正面的掩蔽版采用喷涂的方法制备所述光刻胶，所述掩蔽版露出除加热元件103、测温元件203悬空结构以及环境温度检测器3的测量电阻1032，而其余的SOI硅片正面部分被掩蔽版遮挡住；
第十二步，采用ALD(原子层沉积)方法在热元件103、测温元件203悬空结构以及环境温度检测器3的测量电阻1032的外表面制备氧化铪，或制备氧化铝薄膜，或制备氧化铪/氧化铝复合薄膜，或制备氧化硅/氧化铪/氧化铝复合薄膜，与第十一步形成的薄层氧化硅层共同构成钝化保护层25；
第十三步，去除第十二步制备的保护层，干燥；
第十四步，划片、裂片后得到数量众多分立的单片高温加热器1与分立的单片甲烷气体检测器2；
第十五步，如图4所示，将制备好的单片高温加热器1的正面与单片甲烷气体检测器2的正面贴合对准(由a到b)；随后将单片高温加热器1的键合固定端A106、支撑端105的金属层22上的金属凸块500与对应的单片甲烷气体检测器2上的固定端B 202、键合支撑端204上的金属相接触并施加压力、升温进行键合形成整体的叠层结构形式的如图5所示的本发明的微型甲烷传感器(由b到c)。
或制备方法(二)为圆片级倒装焊封装制备权利要求1所述的微型甲烷传感器， 单片高温加热器1在一个SOI硅圆片上加工，单片甲烷气体检测器2在另一个SOI硅圆片上加工；然后采用圆片级倒装焊封装制备成本发明的微型甲烷传感器。
制备方法(二)的具体步骤为：
第一步，在SOI硅片上制备氧化硅层23；
第二步，图形化顶层硅之上的氧化硅层23，形成掺杂或离子注入所需的窗口；
第三步，掺杂或离子注入形成掺杂硅层24；
第四步，制备金属，并图形化所制备的金属分别形成固定端B 202、若干键合支撑端204、固定端A 102、键合固定端A106、支撑端105、电极引出端104与电极端1041上的金属层22以及固定端A 102、键合固定端A106与电极引出端104之间的连接金属层；
第五步，光刻形成正面结构的刻蚀窗口的图形，随后采用RIE干法刻蚀去除所述刻蚀窗口图形中的第一步生成的氧化硅层23及其下的硅层21，刻蚀停止于埋层氧化硅12，在埋层氧化硅12上形成加热元件103、固定端A 102、键合固定端A106、电极引出端104、多个支撑端105、测量元件102、测温元件203、固定端B 202、键合支撑端204与环境温度检测器3的结构；
第六步，在SOI硅片的正面制备刻蚀保护层，采用光刻胶或PSG(磷硅玻璃)作为刻蚀保护层，所述刻蚀保护层覆盖整个SOI硅片的正面；
第七步，在SOI硅圆片的背面光刻形成背面划片槽的刻蚀窗口图形，采用RIE刻蚀SOI硅片背面的氧化硅与底层硅，形成划片槽；
第八步，在SOI硅片背面光刻形成背面刻蚀窗口图形，采用湿法刻蚀或ICP或DRIE深反应离子刻蚀等干法刻蚀方法刻蚀SOI硅片的底层硅，即衬底11，刻蚀停止于埋层氧化硅12；
第九步，采用氢氟酸溶液或氢氟酸气雾湿法刻蚀从衬底11露出的埋层氧化硅12，释放出加热元件103、测温元件203；
第十步，去除第六步所形成的刻蚀保护层；
第十一步，对暴露出的硅进行氧化，形成薄层氧化硅层；
第十二步，采用保护层覆盖SOI硅片的正面，所述保护层覆盖除加热元件103、测温元件203悬空结构以及环境温度检测器3的测量电阻1032以外的SOI硅片正面部分；可采用光刻胶作为保护层；可采用微喷印设备在精确定位后制备所述光刻胶；也可使用覆盖在SOI的正面的掩蔽版采用喷涂的方法制备所述光刻胶，所述掩蔽版露 出除加热元件103、测温元件203悬空结构以及环境温度检测器3的测量电阻1032，而其余的SOI硅片正面部分被掩蔽版遮挡住；
第十三步，采用ALD方法在热元件103、测温元件203悬空结构以及环境温度检测器3的测量电阻1032的外表面制备氧化铪，或制备氧化铝薄膜，或制备氧化铪/氧化铝复合薄膜，或制备氧化硅/氧化铪/氧化铝复合薄膜，与第十一步形成的薄层氧化硅层一起构成钝化保护层25；
第十四步，去除第十二步制备的保护层，干燥；
上述第一步至第十四步为单片高温加热器1、单片甲烷气体检测器2在各自SOI硅圆片上的加工步骤；
第十五步，将制备好有单片高温加热器1的硅圆片的正面与制备有单片甲烷气体检测器2的硅圆片的正面贴合对准，随后将单片高温加热器1的键合固定端A106、支撑端105的金属层22上的金属凸块500与对应的单片甲烷气体检测器2上固定端B 202、若干键合支撑端204接触并施加压力、升温进行键合形成含有单片高温加热器1的硅圆片与含有单片甲烷气体检测器2的硅圆片为一体的叠层式硅圆片；
第十六步，沿第七步所述在制备有单片甲烷气体检测器2的SOI硅圆片背面上的划片槽划片，沿本步骤所述划片槽划片的切割深度只有一个SOI硅圆片的厚度，去除掉所述制备有单片甲烷气体检测器2的SOI硅圆片上的切割的硅，露出单片高温加热器1上的电极引出端104；
第十七步，沿第七步所述在制备有单片高温加热器1的SOI硅圆片背面上的划片槽划片；沿本步骤所述划片槽划片的切割深度为两个SOI硅圆片的厚度；裂片得到本发明的基于倒装焊封装的微型甲烷传感器。

Claims (3)

  1. 一种基于倒装焊封装的微型甲烷传感器，其特征在于：它包括单片高温加热器(1)、单片甲烷气体检测器(2)和环境温度检测器(3)；
    所述单片高温加热器(1)包括：支座A(101)、加热元件(103)、2个固定端A(102)、2个键合固定端A(106)、多个电极引出端(104)、多个支撑端(105)；
    所述单片甲烷气体检测器(2)包括支座B(201)、测温元件(203)、2个固定端B(202)、若干键合支撑端(204)；
    所述环境温度检测器(3)包括两个电极端(1041)及测量电阻(32)；所述环境温度检测器(3)设在单片高温加热器(1)的支座A(101)上，或单片甲烷气体检测器(2)的支座B(201)上，或在单片高温加热器(1)的支座A(101)与单片甲烷气体检测器(2)的支座B(201)上都设置有环境温度检测器(3)；
    所述支座A(101)与支座B(201)都包括硅衬底(11)与硅衬底(11)之上的埋层氧化硅(12)；
    所述固定端A(102)、键合固定端A(106)、支撑端(105)、电极引出端(104)与电极端(1041)均相互独立的设在支座A(101)上的埋层氧化硅(12)上；固定端A(102)及电极端(1041)均由硅层(21)加工而成，并在硅层(21)上设有氧化硅层(23)、在氧化硅层(23)上设有金属层(22)；所述固定端A(102)及电极端(1041)的硅层(21)内均设有掺杂硅层(24)，金属层(22)均通过氧化硅层(23)的窗口与掺杂硅层(24)直接接触并构成欧姆接触；键合固定端A(106)、电极引出端(104)与支撑端(105)均由硅层(21)加工而成，并在硅层(21)上设有氧化硅层(23)，在氧化硅层(23)上设有金属层(22)；加热元件(103)同样由硅层(21)加工而成，并在硅层(21)的外表面设有钝化保护层(25)；所述加热元件(103)设有高温加热单元(1031)、两个对称设置的硅悬臂(1032)；所述高温加热单元(1031)为圆环状，或多个加热条的并联；所述硅悬臂(1032)的长度大于300um；所述单个的硅悬臂(1032)的一端与高温加热单元(1031)相连，另一端与支座A(101)上的一个固定端A(102)相连；电极引出端(104)也设在支座A(101)的埋层氧化硅(12)上；每个键合固定端A(106)、固定端A(102)均与一个对应的电极引出端(104)的一端相连，尤其是金属层(22)是相连接的；电极引出端(104)远离固定端A(102)和键合固定端A(106)，其间距离应使单片甲烷气体检测器(2)倒装焊在单片高温 加热单元上(1)之后，电极引出端(104)与电极端(1041)不被单片甲烷气体检测器(2)遮挡，在电极引出端(104)和电极端(1041)上可以向外进行引线键合；在键合固定端A(106)、支撑端(105)的金属层(22)上设有高度相同的金属凸块(500)；2个键合固定端A(106)与2个固定端A(102)并排间隔布置，排列顺序分别为一个键合固定端A(106)、一个固定端A(102)、另一个固定端A(102)、另一个键合固定端A(106)；
    所述测温元件(203)设有测温单元(2031)、两个对称设置的连接臂(2033)，2个对称设置的支撑臂(2032)；所述测温单元(2031)、连接臂(2033)、支撑臂(2032)、固定端B(202)依次相连；所述测温单元(2031)与单片高温加热器(1)的高温加热单元(1031)结构形状相同，尺寸稍大；所述键合支撑端(204)、固定端B(202)均相互独立的设在支座B(201)上的埋层氧化硅(12)上；若在支座B(201)上设有环境温度检测器(3)，则环境温度检测器(3)与固定端B(202)及若干键合支撑端(204)相互独立、不存在硅层(21)上的连接；所述键合支撑端(204)、固定端B(202)均由硅层(21)加工而成，均包括硅层(21)、设在硅层(21)外的氧化硅层(23)、设在氧化硅层(23)上的金属层(22)；固定端B(202)的硅层(21)内设有掺杂硅层(24)，金属层(22)通过氧化硅层(23)的窗口与固定端B(202)的掺杂硅层(24)直接接触构成欧姆接触；测温元件(203)由硅层(21)加工而成，并在硅层(21)的外表面设有钝化保护层(25)，悬在空气中的测温元件(203)通过固定端B(202)固定在支座B(201)上的埋层氧化硅(12)上，两个固定端B(202)构成测温元件(203)的电通路的两个端子；
    单片甲烷气体检测器(2)的正面与单片高温加热器(1)的正面平行相对，对准后通过金属凸点(500)的金属键合实现二者的紧密固定与电连接；对准后的单片甲烷气体检测器(2)在单片高温加热器(1)上的投影特征为：单片甲烷气体检测器(2)的2个固定端B(202)分别与单片高温加热器(1)的2个键合固定端A(106)重合，单片甲烷气体检测器(2)的键合支撑端(204)分别与单片高温加热器(1)对应的支撑端(105)重合，测温单元(2031)的中心与单片高温加热器(1)的高温加热单元(1031)的中心重合，二者的中心到各自的支座具有相同的距离；单片甲烷气体检测器(2)与单片高温加热器(1)通过金属凸点(500)金属键合固定后，测温单元(2031)与单片高温加热器(1)的高温加热单元(1031)之间的距离的距离范围为3至200um；单片甲烷气体检测器(2)的测温元件(203)通过两个固定端B(202)、 单片高温加热器(1)的两个键合固定端A(106)及其上的金属凸点(500)、与键合固定端A(106)相连接的两个电极引出端(104)在单片高温加热器(1)上构成一个二端子器件，在所述的与键合固定端A(106)相连接的两个电极引出端(104)上进行引线键合可实现与外部电路的连接。
  2. 一种基于倒装焊封装的微型甲烷传感器的应用方法，使用时使单片甲烷气体检测器(2)位于单片高温加热器上(1)的下方，给单片甲烷气体检测器(2)与环境温度检测器(3)通以微弱电流不使测温元件(203)与测量电阻(32)发热；而给单片高温加热器(1)通电后则使加热元件(103)加热至500℃以上的高温，进入电流-电阻特性曲线中转折点左侧的工作区域；所述转折点为电阻随电流或电压增大而出现的电阻最大点，当电流或电压继续增大时，电阻不再继续增大反而减小；当没有甲烷气体时，单片甲烷气体检测器(2)的测温元件(203)受加热元件(103)的加热高温影响温度升高，电阻增大；而当甲烷气体出现时及浓度增加时，加热元件(103)的温度降低，测温元件(203)受其影响温度也降低，导致自身电阻的降低，于是通过电学检测的方法可以检测甲烷的出现及甲烷浓度变化；环境温度检测器(3)独立探测本发明微型甲烷传感器的片上温度用于甲烷浓度数据的温度补偿。
  3. 如权利要求1所述的基于倒装焊封装的微型甲烷传感器的制备方法，其特征是：其包括两种制备方法：
    制备方法(一)首先制备分离的单片高温加热器(1)与分离的单片甲烷气体检测器(2)，所述的单片高温加热器(1)单片甲烷气体检测器(2)采用SOI硅片加工，单片高温加热器(1)与单片甲烷气体检测器(2)制备时可以在同一SOI硅片上加工，或者在不同的SOI硅片上加工；然后将加工好的分离的单片高温加热器(1)与分离的单片甲烷气体检测器(2)采用倒装焊封装制备成整体结构形式的本发明的微型甲烷传感器；
    其具体制备步骤为：
    第一步，在SOI硅片上制备氧化硅层(23)；
    第二步，图形化顶层硅之上的氧化硅层(23)，形成掺杂或离子注入所需的窗口；
    第三步，掺杂或离子注入形成掺杂硅层(24)；
    第四步，淀积或蒸发制备金属层，并图形化所制备的金属形成固定端B(202)、若干键合支撑端(204)、固定端A(102)、键合固定端A(106)、支撑端(105)、电 极引出端(104)、电极端(1041)的金属层(22)，以及固定端A(102)、键合固定端A(106)与电极引出端(104)之间的连接金属层；
    第五步，光刻形成正面结构的刻蚀窗口的图形，随后采用RIE(Reactive IonEtching，反应离子刻蚀)干法刻蚀去除所述刻蚀窗口图形中的第一步生成的氧化硅层(23)及其下的硅层(21)，刻蚀停止于埋层氧化硅(12)，在埋层氧化硅(12)上形成加热元件(103)、固定端A(102)、键合固定端A(106)、电极引出端(104)、多个支撑端(105)、测量元件(102)、测温元件(203)、固定端B(202)、键合支撑端(204)与环境温度检测器(3)的结构及划片槽；
    第六步，在SOI硅片的正面制备刻蚀保护层，所述刻蚀保护层覆盖整个SOI硅片的正面；
    第七步，在SOI硅片背面光刻形成背面刻蚀窗口的图形，采用湿法刻蚀或ICP(Inductively Coupled Plasma，感应耦合等离子体刻蚀)或DRIE(Deep Reactive Ion Etching，深反应离子刻蚀)等干法刻蚀方法刻蚀SOI硅片的底层硅，即衬底(11)，刻蚀停止于埋层氧化硅(12)；
    第八步，采用氢氟酸溶液或氢氟酸气雾湿法刻蚀从衬底(11)露出的埋层氧化硅(12)，释放出加热元件(103)、测温元件(203)，释放出加热元件、测温元件；
    第九步，去除第六步所形成的刻蚀保护层；
    第十步，对暴露出的硅进行氧化，形成薄层氧化硅层；
    第十一步，采用保护层覆盖SOI硅片的正面，所述保护层覆盖除加热元件(103)、测温元件(203)悬空结构以及环境温度检测器(3)的测量电阻(1032)以外的SOI硅片正面部分；可采用光刻胶作为保护层；可采用微喷印设备在精确定位后制备所述光刻胶；也可使用覆盖在SOI的正面的掩蔽版采用喷涂的方法制备所述光刻胶，所述掩蔽版仅露出除加热元件(103)、测温元件(203)悬空结构以及环境温度检测器(3)的测量电阻(1032)，而其余的SOI硅片正面部分被掩蔽版遮挡住；
    第十二步，采用ALD原子层沉积方法在热元件(103)、测温元件(203)悬空结构以及环境温度检测器(3)的测量电阻(1032)的外表面制备氧化铪，或制备氧化铝薄膜，或制备氧化铪/氧化铝复合薄膜，或制备氧化硅/氧化铪/氧化铝复合薄膜，与第十步形成的薄层氧化硅层共同构成钝化保护层(25)；
    第十三步，去除第十一步制备的保护层，干燥SOI硅片；
    第十四步，划片、裂片后得到数量众多分立的单片高温加热器(1)与分立的单 片甲烷气体检测器(2)；
    第十五步，将制备好的单片高温加热器(1)的正面与单片甲烷气体检测器(2)的正面贴合对准，随后将单片高温加热器(1)的键合固定端A(106)、支撑端(105)的金属层(22)上的金属凸块(500)与对应的单片甲烷气体检测器(2)上的固定端B(202)、键合支撑端(204)上的金属相接触并施加压力、升温进行键合形成整体的叠层结构形式的本发明的微型甲烷传感器；
    或制备方法(二)为圆片级倒装焊封装制备权利要求1所述的微型甲烷传感器，单片高温加热器(1)在一个SOI硅圆片上加工，单片甲烷气体检测器(2)在另一个SOI硅圆片上加工；然后采用圆片级倒装焊封装制备成本发明的微型甲烷传感器；
    其具体步骤为：
    第一步，在SOI硅片上制备氧化硅层(23)；
    第二步，图形化顶层硅之上的氧化硅层(23)，形成掺杂或离子注入所需的窗口；
    第三步，掺杂或离子注入形成掺杂硅层(24)；
    第四步，制备金属，并图形化所制备的金属分别形成固定端B(202)、若干键合支撑端(204)、固定端A(102)、键合固定端A(106)、支撑端(105)、电极引出端(104)与电极端(1041)上的金属层(22)以及固定端A(102)、键合固定端A(106)与电极引出端(104)之间的连接金属层；
    第五步，光刻形成正面结构的刻蚀窗口的图形，随后采用RIE干法刻蚀去除所述刻蚀窗口图形中的第一步生成的氧化硅层(23)及其下的硅层(21)，刻蚀停止于埋层氧化硅(12)，在埋层氧化硅(12)上形成加热元件(103)、固定端A(102)、键合固定端A(106)、电极引出端(104)、多个支撑端(105)、测量元件(102)、测温元件(203)、固定端B(202)、键合支撑端(204)与环境温度检测器(3)的结构；
    第六步，在SOI硅片的正面制备刻蚀保护层，所述刻蚀保护层覆盖整个SOI硅片的正面；
    第七步，在SOI硅圆片的背面光刻形成背面划片槽的刻蚀窗口图形，采用RIE刻蚀SOI硅片背面的氧化硅与底层硅，形成划片槽；
    第八步，在SOI硅片背面光刻形成背面刻蚀窗口图形，采用湿法刻蚀或ICP或DRIE(深反应离子刻蚀)等干法刻蚀方法刻蚀SOI硅片的底层硅，即衬底(11)，刻蚀停止于埋层氧化硅(12)；
    第九步，采用氢氟酸溶液或氢氟酸气雾湿法刻蚀从衬底(11)露出的埋层氧化硅 (12)，释放出加热元件(103)、测温元件(203)，释放出加热元件、测温元件；
    第十步，去除第六步所形成的刻蚀保护层；
    第十一步，对暴露出的硅进行氧化，形成薄层氧化硅层；
    第十二步，采用保护层覆盖SOI硅片的正面，所述保护层覆盖除加热元件(103)、测温元件(203)悬空结构以及环境温度检测器(3)的测量电阻(1032)以外的SOI硅片正面部分；可采用光刻胶作为保护层；可采用微喷印设备在精确定位后制备所述光刻胶；也可使用覆盖在SOI的正面的掩蔽版采用喷涂的方法制备所述光刻胶，所述掩蔽版仅露出加热元件(103)、测温元件(203)悬空结构以及环境温度检测器(3)的测量电阻(1032)，其余的SOI硅片正面部分被掩蔽版遮挡住；
    第十三步，采用ALD原子层沉积方法在热元件(103)、测温元件(203)悬空结构以及环境温度检测器(3)的测量电阻(1032)的外表面制备氧化铪，或制备氧化铝薄膜，或制备氧化铪/氧化铝复合薄膜，或制备氧化硅/氧化铪/氧化铝复合薄膜，与第十一步形成的薄层氧化硅层一起构成钝化保护层(25)；
    第十四步，去除第十二步制备的保护层，干燥；
    上述第一步至第十四步为单片高温加热器(1)、单片甲烷气体检测器(2)在各自SOI硅圆片上的加工步骤；
    第十五步，将制备好有单片高温加热器(1)的硅圆片的正面与制备有单片甲烷气体检测器(2)的硅圆片的正面贴合对准，随后将单片高温加热器(1)的键合固定端A(106)、支撑端(105)的金属层(22)上的金属凸块(500)与对应的单片甲烷气体检测器(2)上固定端B(202)、若干键合支撑端(204)接触并施加压力、升温进行键合形成含有单片高温加热器(1)的硅圆片与含有单片甲烷气体检测器(2)的硅圆片为一体的叠层式硅圆片；
    第十六步，沿第七步所述在制备有单片甲烷气体检测器(2)的SOI硅圆片背面上的划片槽划片，沿本步骤所述划片槽划片的切割深度只有一个SOI硅圆片的厚度，去除掉所述制备有单片甲烷气体检测器2的SOI硅圆片上的切割的硅，露出单片高温加热器(1)上的电极引出端(104)；
    第十七步，沿第七步所述在制备有单片高温加热器(1)的SOI硅圆片背面上的划片槽划片；沿本步骤所述划片槽划片的切割深度为两个SOI硅圆片的厚度；裂片得到本发明的基于倒装焊封装的微型甲烷传感器。
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