CN102520032A - CMUT (Capacitive Micromachined Ultrasonic Transducer)-based biochemical transducer and manufacturing method thereof - Google Patents
CMUT (Capacitive Micromachined Ultrasonic Transducer)-based biochemical transducer and manufacturing method thereof Download PDFInfo
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Abstract
The invention provides a CMUT (Capacitive Micromachined Ultrasonic Transducer)-based biochemical transducer and a manufacturing method thereof. The CMUT-based biochemical transducer comprises a sensitivity identification material layer, an upper electrode, a silicon dioxide film, a silicon strut, a lower electrode, a silicon dioxide insulating layer and a silicon substrate in sequence from top to bottom. According to the biochemical transducer, the metal lower electrode is completely isolated from the silicon substrate, the method which takes the substrate as the lower electrode in the conventional CMUT based biochemical transducer is replaced, the power consumption is reduced, the electric field strength between the upper electrode and the lower electrode is greatly improved, and the electromechanical coupling capability is strengthened; the lower electrode is only positioned inside a cavity formed by the silicon dioxide film, the silicon strut and the silicon dioxide insulating layer, so that the lower side of the film is effectively vibrated rather than covering the whole silicon substrate, the parasitic capacitance is effectively reduced, the electromechanical conversion ratio is further increased, and the effective utilization rate of electric energy is improved.
Description
Technical field
The invention belongs to MEMS and technological field of biochemistry, particularly a kind of biochemical sensor based on CMUT and preparation method thereof.
Background technology
The biological and chemical sensor is many by mass sensor and polymers function layer be combined into, changes the detection that the translation that causes resonant frequency realizes the biological chemistry amount through quality.Common based on MEMS (Micro Electro-Mechanical Systems; The micromachine electronic system) the biochemical sensor microstructure of technology mainly contains micro-cantilever, piezoelectric quartz crystal, FBAR, SAW resonator; Though these measurement structure are very ripe, because the architectural feature of himself has limited the raising of resonant frequency and quality factor, for example; The resonant frequency in air of cantilever beam structure commonly used is tens KHz, and quality factor is less than 100; And in liquid because the increase of damping; Resonant frequency and quality factor will reduce significantly that (resonant frequency drops to tens KHz; Quality factor is less than 10), thereby based on the then very difficult detection that realizes the biochemical substances of high sensitivity, high-resolution and littler quality limit of the biochemical sensor of these structures.
With respect to above micro sensing structure; What just began one's study in recent years shows more superiority based on the biochemical sensor of CMUT (Capactive Micromachined Ultrasonic Transducer, electric capacity micromachined ultrasonic transducer) overcoming on the above difficult problem.Have benefited from MEMS micro-processing technology and CMUT self unique texture, the littler film quality that CMUT had, higher resonant frequency (can reach tens MHz) and quality factor (can reach hundreds of) determine it can realize the more measurement of high sensitivity and littler quality limit; Characteristics such as it is prone to processing, be prone to array, easy of integration provide advantage for realizing that the different biochemical substances of hyperchannel are measured simultaneously.At present, occurred adopting CMUTs to detect the dimethyl methyl phosphonate test of (dimethyl methylphosphonate is called for short DMMP) as biochemical sensor, it detects quality limit is 0.162 * 10
-16G, volume sensitivity is 37.38ppb/Hz; Also adopt CMUTs to detect isopropyl alcohol, acetone, alcohol and water, detecting quality limit is 10
-15G, volume sensitivity is 41.6ppb/Hz.But these biochemical sensors are based on some common CMUT structures more; When work because of big stray capacitance, factor affecting such as film quality, silicon base high impedance and isolation layer charging phenomenon greatly; Limited the further raising of detection sensitivity and quality limit, thereby these conventional CMUT inadaptability in structures can not be given full play to many advantages of CMUT when using as biochemical sensor in other words as biochemical sensor.
Summary of the invention
Technical matters to be solved by this invention provides a kind of biochemical sensor based on CMUT and preparation method thereof; To avoid bottom electrode isolation layer charging phenomenon, to reduce stray capacitance and electric energy loss; Further improve electromechanical coupling factor and measure sensitivity, realize the more detection of trace toxic biochemical substances.
The present invention is based on the biochemical sensor of CMUT; Comprise first parts and second parts that are bonded together up and down; Said first parts comprise first monocrystalline silicon and the silica membrane layer that forms in the first monocrystalline silicon upper surface oxidation; Said first monocrystalline silicon middle part is provided with cavity, and this cavity runs through first monocrystalline silicon and terminates in the silica membrane layer on thickness direction, be disposed with the upper electrode layer and the sensitive material layer of metal at silica membrane layer upper surface; Said second parts comprise silicon base and silicon dioxide insulating layer; Said silicon base is provided with through hole and groove along thickness direction; The two connects on its thickness direction; Said silicon dioxide insulating layer is arranged on the inside surface of silicon base upper surface, lower surface and through hole and groove; The silicon dioxide insulating layer of silicon base upper surface is provided with bottom electrode; This bottom electrode comprises the metal film layer that is deposited on the silicon dioxide insulating layer upper surface and is deposited on the column in the through hole of through-silicon upper surface of substrate; Wherein, the metal film layer of said bottom electrode does not cover whole silicon dioxide insulating layer fully but covers center line and the central lines of top electrode of metal film layer of center section and the bottom electrode of silicon dioxide insulating layer, and the silicon dioxide insulating layer that said first parts and second parts are positioned at the silicon base upper surface through the remaining part of first parts, first monocrystalline silicon and second parts carries out bonding and forms.
Said silica membrane layer thickness scope is 0.1 μ m～0.5 μ m, and effective vibration surface diameter range of silica membrane layer is 10 μ m～20 μ m;
Remaining part formed silicon pillar after said first monocrystalline silicon middle part was provided with cavity, and the width of this silicon pillar highly is 2～5 μ m greater than 40 μ m;
The height of said cavity is 0.5～1.2 μ m;
The thickness of the metal film layer of said bottom electrode is 1～4 μ m, and the lateral dimension of metal film layer is at least effective vibration film ground corresponding size half the of silica membrane layer, and is at least 1 μ m with the lateral separation of the monocrystalline silicon internal face of first parts;
Said through hole is used to bottom electrode and the external world provides electrical connecting passage, and its through hole height is at least 40 μ m, and its through-hole diameter is 3～4 μ m;
Said top electrode covers whole silica membrane or covers the middle subregion of silica membrane;
Said silica membrane, top electrode, responsive identification material layer form vibration film jointly, and the thickness of this vibration film is less than 1.5 μ m.
The preparation method who the present invention is based on the biochemical sensor of CMUT may further comprise the steps:
(1) get first monocrystalline silicon and with its upper and lower surfaces respectively oxidation form silica membrane layer (this moment, not oxidized monocrystalline silicon promptly was called first monocrystalline silicon); Its lower surface silicon dioxide layer middle part of etching forms cavity graphical window; Expose monocrystalline silicon; Etching is exposed to the monocrystalline silicon in the window and stops at its upper surface silicon dioxide layer; The silicon dioxide layer that exposes the upper strata, removal is positioned at the residue silicon dioxide layer of the first monocrystalline silicon lower surface and its lower surface is carried out chemically mechanical polishing then, forms first parts; Wherein, the zone that is etched in the middle part of first monocrystalline silicon forms cavity, and monocrystalline silicon partly forms the monocrystalline silicon pillar around the remaining cavity;
(2) get second monocrystalline silicon and its upper and lower surfaces oxidation formed the silica membrane layer; Etching silicon dioxide layer up and down makes it form graphical window respectively; Expose second monocrystalline silicon; Second monocrystalline silicon about etching is exposed in the graphical window is until perforation, and the zone that is etched at second monocrystalline silicon middle part this moment forms through hole and groove from top to bottom; Oxidation second monocrystalline silicon upper and lower surfaces and through hole and groove inside surface form complete silicon dioxide isolation layer; The chemically mechanical polishing second monocrystalline silicon upper surface silicon dioxide insulating layer; Deposit metallic material in this silicon dioxide insulating layer upper surface and through hole then; As bottom electrode, so far form second parts after the photoetching;
(3) under vacuum environment; Second parts that first parts that step (1) is obtained and step (2) obtain carry out bonding; Wherein, first parts are positioned at the top of second parts, and just the silicon pillar of first parts is positioned on the silicon dioxide insulating layer of second parts, the second monocrystalline silicon upper surface; So, the silicon dioxide insulating layer of the second monocrystalline silicon upper surface is with the cavity sealing of first parts;
(4) the silica membrane upper surface at the first parts upper surface deposits the metal film layer as top electrode, and at metal film layer upper surface deposition sensitive material layer, photoetching is used for lead-in wire on sensitive layer at last.
Compared with prior art, biochemical sensor that the present invention is based on CMUT and preparation method thereof has the following advantages at least:
(1) further reduces vibration film thickness (less than 0.5 μ m) and quality, can effectively improve the film resonant frequency, and then improve CMUT working sensitivity and biochemical substances detection limit.
(2) internal stress is littler and connection reliability is higher between vibration film and the pillar, has effectively guaranteed film favorable mechanical performance and functional reliability.
(3) with respect to the situation of whole silicon base as bottom electrode, the utilization metallic film increases substantially the conductive capability of bottom electrode as bottom electrode, strengthens the electric field intensity between two electrodes, and then electromechanical coupling factor is greatly improved.
(4) no electric isolation layer on the metal bottom electrode, avoided because of bottom electrode isolation layer charging phenomenon in the highfield to the influence of CMUT job stability.
(5) the metal bottom electrode only is positioned at the below of effective vibration film, and the influence of stray capacitance has effectively been reduced in the inside of cavity, further improves the serviceability of sensor.
(6) form groove at the silicon base back side, reduced to be used for the length that bottom electrode is electrically connected through hole,, reduce power consumption reducing difficulty of processing and in the time, also effectively having reduced series resistance value.
Description of drawings
Fig. 1 is the structural representation that the present invention is based on the biochemical sensor of CMUT;
Fig. 2 is the flow process chart of sensor of the present invention.
Label among the figure is represented as follows:
| 1 | Responsive |
2 | The |
| 3 | Silicon dioxide |
4 | |
| 5 | |
6 | |
| 7 | |
8 | |
| 9 | Through |
10 | |
| 11 | First |
12 | Second monocrystalline silicon |
Embodiment
Below in conjunction with accompanying drawing, biochemical sensor of the present invention is based on CMUT (Capacitive Micro-fabricated Ultrasonic Transducer) and preparation method thereof is done detailed description:
See also shown in Figure 1ly, the invention discloses a kind of biochemical sensor, comprise first parts and second parts that are bonded together up and down based on CMUT.The silica membrane 2 that said first parts comprise first monocrystalline silicon, form in the first monocrystalline silicon upper surface oxidation, be deposited on silica membrane 2 upper surfaces and as the metal film layer of top electrode 7, be deposited on the sensitivity identification material layer 1 of metal film layer upper surface; Wherein, The middle part of said first monocrystalline silicon is etched with cavity 8; Expose silica membrane 2, first monocrystalline silicon that stays forms the silicon pillar 6 with the second portion bonding; Said second parts comprise silicon base 4, through hole 9, groove 10, bottom electrode 5 and the whole silicon dioxide insulating layer 3 that forms in silicon base 4 upper and lower surfaces, through hole 9 and groove 10 inside surface oxidations; Wherein said through hole 9 and groove 10 are about silicon base 4 center lines symmetry and on its thickness direction, be communicated with and run through; Said silicon dioxide insulating layer 3 covers silicon base 4, through hole 9 and groove 10 inside surfaces; Be used for the isolated whole monocrystal silicon substrate 4 of electricity; Said bottom electrode 5 comprises the column in metal film layer and the through hole 9 on the silicon dioxide insulating layer 3, and thin metal layer is positioned at cavity 8 inside.
Please continue to consult shown in Figure 1, the biochemical sensor structure that the present invention is based on CMUT comprises from top to bottom successively: responsive identification material layer 1, top electrode 7, silica membrane 2, silicon pillar 6, bottom electrode 5, silicon dioxide insulating layer 3, silicon base 4.Wherein, said silicon base 4 is followed successively by bottom electrode from top to bottom and is electrically connected through hole 9 and silicon base groove 10, and wherein, bottom electrode is electrically connected through hole 9 and is in silicon base 4 centers with silicon base groove 10, and about silicon base 4 central shafts symmetry; Said bottom electrode electrical connection through hole 9 is communicated with on silicon base 4 thickness directions with silicon base groove 10 and runs through; The inside surface that said silicon base 4 upper and lower surfaces and bottom electrode are electrically connected through hole 9 and silicon base groove 10 forms silicon dioxide isolation layer 3 through oxidation.Said bottom electrode 5 comprises that the metal film layer on the silicon dioxide insulating layer 3 is electrically connected the through hole 9 interior columns identical with the metallic film layer material with bottom electrode.Said silica membrane 2, silicon pillar 6 and cavity 8 are formed silicon dioxide insulating layer 3 sealed cavities 8 through oxidation, etching by same monocrystalline silicon.Said silica membrane 2, top electrode 7 and the responsive identification material layer 1 common vibration film that forms.
Said silica membrane 2 is major parts of CMUT vibration film; For reduce film quality, improve resonant frequency as far as possible; And then increase the sensitivity of said sensor biochemical substances; Realize littler quality limit value measurement; The silica membrane thickness range is 0.1 μ m～0.5 μ m, and effective vibration surface diameter range of silica membrane is 10 μ m～20 μ m, and effective vibration surface diameter of said silica membrane refers to that silica membrane is positioned at lateral dimension or the width dimensions directly over the cavity; Owing to no electric isolation layer on the bottom electrode 5, therefore, said silica membrane is simultaneously as the electric isolation layer between top electrode 7 and the bottom electrode 5, to guarantee the security of working sensor in addition.
Said silicon pillar 6 lateral dimensions should to guarantee its holding strength, for reduce cavity height as far as possible, strengthen electromechanical coupling factor simultaneously greater than 40 μ m, and silicon pillar 6 altitude ranges are 2～5 μ m.
Said cavity 8; For increasing electromechanical coupling factor; Improve sensitivity, cavity height should be as far as possible little, and the cavity 8 significant height values height that equals silicon pillar 6 deducts bottom electrode 5 thickness here; Its scope is 0.5 μ m～1.2 μ m, and the significant height value of said cavity refers to the cavity height between silica membrane and the bottom electrode.Silica membrane 2, silicon pillar 6 and cavity 8 successively form through oxidation, back etching on same monocrystalline silicon piece; Do not adopt common thin film deposition or bonding technology; Therefore internal stress is littler between silicon pillar 6 and the silica membrane 2, connection reliability is higher, improves vibration of thin membrane mechanical property and functional reliability.
Said electrical connection through hole 9 is used to bottom electrode 5 and with the external world electrical connecting passage is provided, and its through hole height is tried one's best little but is at least 40 μ m, guarantees through hole surrounding structure intensity when reducing resistance in series as far as possible; Its through-hole diameter is 3 μ m～4 μ m, is guaranteeing that low resistance in series reduces difficulty of processing simultaneously, shortens process time.
Said silicon base groove 10 on the one hand with respect to the electrical connection through hole situation that runs through whole silicon base, can significantly reduce difficulty of processing, shorten the process-cycle; Make things convenient for the fixing of whole sensor on the other hand and be electrically connected.Silicon base groove 10 height are decided because of the height that is electrically connected through hole 9, and groove 10 is communicated with and runs through whole silicon base with through hole 9; Its lateral dimension is satisfying under the above square structure intensity of the groove prerequisite, and suitable conveniently to be processed as, its lateral dimension is at least 4 μ m.
Said silicon dioxide insulating layer 3, its gauge are at least 2 μ m, to realize that bottom electrode 5 and silicon base 4 electricity isolation fully are beneficial to reduce stray capacitance.
Said top electrode 7 covers whole silica membrane 2, to strengthen electric field intensity, reduces pick-up voltage, and its gauge scope is 0.5～1 μ m.
Said responsive identification material layer 1 is the functional material layer of identification detection of biological chemical substance, and different sensitive materials can be discerned different biochemicals, and it is covered on the top electrode 7, and thickness is less than 1 μ m.Silica membrane 2, top electrode 7, the responsive identification material layer 1 common vibration film that forms, its thickness is less than 1.5 μ m.
The present invention is based on the biochemical sensor of CMUT, its main structure parameters is:
Silica membrane effective diameter: 10 μ m～20 μ m
Silicon dioxide vibration film thickness: 0.1 μ m～0.5 μ m
Top electrode thickness: 0.5 μ m～1 μ m
Bottom electrode thickness: 1 μ m～4 μ m
Vibration film gross thickness: less than 1.5 μ m
Cavity height: 0.5～1.2 μ m
Bottom electrode is electrically connected through-hole diameter: 3 μ m～4 μ m
The manufacturing process of a kind of biochemical sensor based on CMUT of the present invention is described below in conjunction with Fig. 2:
(1) (111) crystal face first monocrystalline silicon 11 two-sided oxidations to being positioned at the left side, strict control oxidated layer thickness forms silica membrane 2 respectively at the upper and lower surfaces of (111) crystal face first monocrystalline silicon 11; To being positioned at < 111>crystal face second monocrystalline silicon 12 two-sided oxidations on the right, the control oxidated layer thickness forms silicon dioxide insulating layer 3 respectively at the upper and lower surfaces of (111) crystal face second monocrystalline silicon 12.
(2) be exposed to the silicon dioxide oxide layer in the window to the silica membrane litho pattern window of first monocrystalline silicon, 11 lower surfaces on the left side, and with the HF solution removal, form the silicon dioxide masking layer; To silicon dioxide insulating layer 3 each photoetching definite shape window of second monocrystalline silicon, 12 upper and lower surfaces on the right, and expose the silicon dioxide layer in the circular window, form the silicon dioxide masking layer with the HF solution removal.
(3) center section that first monocrystalline silicon, the 11 usefulness wet methods or the plasma etching on the left side is fallen first monocrystalline silicon 11 forms cavity 8, keeps the part of both sides, forms silicon pillar 6; Right second monocrystalline silicon, 12 usefulness are formed through hole 9 and groove 10 with the quadrat method etching; Wherein, Part second monocrystalline silicon 12 of through hole 9 for etching away the silicon dioxide insulating layer 3 of second monocrystalline silicon, 12 upper surfaces and being adjacent, said groove 10 is downwards until the silicon dioxide insulating layer that runs through second monocrystalline silicon, 12 lower surfaces from through hole 9 lower limbs.
(4) with the silica membrane of first monocrystalline silicon, 11 lower surfaces on the HF solution removal left side, and carry out chemical machinery and cut open light, form first; To the further oxidation of second monocrystalline silicon on the right, promptly form silicon dioxide insulating layer with groove in second monocrystalline silicon end and an end further oxidation adjacent of second monocrystalline silicon adjacent with through hole.
(5) with LPCVD technology plated metal in silicon dioxide insulating layer 3 upper surfaces and the through hole 9 of the second monocrystalline silicon upper surface on the right; Form bottom electrode 5, this bottom electrode 5 comprises metallic film that is arranged in the silicon dioxide insulating layer upper surface and the column that is deposited on through hole.
(6) both sides of the metallic film part of electrode 5 are fallen down in photoetching, and the silicon dioxide layer 3 that exposes is carried out topochemistry mechanical buffing, form second portion.
(7) under vacuum environment, the first of step (4) formation and the second portion of step (6) formation are carried out anode linkage, wherein, first is last, and second portion is following, and second monocrystalline silicon of second portion forms the silicon base of whole sensor.
(8) at the silica membrane upper surface of first's upper surface with the metal film layer of LPCVD deposition techniques as top electrode 7, adopt LPCVD deposition techniques sensitive material layer 1 at the metal film layer upper surface, photoetching is used for lead-in wire on sensitive material layer 1 at last.
The shape of said cavity 8 can circle, rectangle, square or other polygon, and specifically applicable cases is selected suitable shape; Said electrical connection through hole 9 and silicon base groove 10 are circular, also can be other shape, to be prone to processing, to be applicable to that concrete applicable cases is a principle of design.The size of silicon pillar 6, bottom electrode 5, cavity 8 should be taken all factors into consideration, and makes the height of formed cavity 8 minimum as far as possible.The material of top electrode 7 and bottom electrode 5 can be identical; Also can be different, can suitably select according to functional requirement, cost etc., and top electrode 7 can cover whole silica membrane 2; Certainly; Also can only cover the subregion in the middle of the silica membrane 2, metallic film can form the top electrode of different shape and size through photoetching in deposition on the silica membrane 2 and after covering fully, will make the serviceability optimum of CMUT in a word.Responsive identification material layer 1 can be used corresponding sensitive material according to the biochemical substances of required detection.In addition; The biochemical sensor that the present invention is based on CMUT is a sensor unit; Then be that a plurality of sensing units are formed array format in practical application; Sensor unit quantity and formed array format can design according to functional requirement, fabrication process condition, cost voluntarily, and generally this design is comparatively simple, ripe, no longer discusses here.In addition, go back the last encapsulating structure of considered design during application, to prevent the influences such as corrosion of biochemical substances to sensor.At last, corresponding to different working temperatures, the hot expansibility of metal electrode is accurately confirmed the WV of this temperature lower sensor to the influence of sensor cavities height under the considered, to realize the accurate measurement to material to be detected.
The key technical indexes of the present invention is following:
Measuring media: micro-biochemical substances
Volume sensitivity: be superior to 50ppb/Hz
Quality limit value: be superior to 10
-18g
Response time: less than 15min
Measuring accuracy: be superior to 8%FS
Working temperature :-20 ℃-150 ℃
A kind of biochemical sensor based on CMUT of the present invention can effectively improve the biochemical substances detection sensitivity, realizes that more micro-biochemical substances detects; Avoid conventional, improve working sensor stability based on bottom electrode electricity isolation layer charging phenomenon in the biochemical sensor work of CMUT; Adopt metal electrode as bottom electrode; And with metal electrode layer and silicon base electricity isolation fully; Replace conventional based in the biochemical sensor of CMUT with the way of silicon base as bottom electrode, increase substantially the electric field intensity between two electrodes up and down, strengthen the mechanical-electric coupling ability; Bottom electrode only is positioned at cavity inside, the below of effective vibration film, but not cover whole silicon base, and effectively reduce stray capacitance, further increase dynamo-electric transformation ratio, improved the effective rate of utilization of electric energy.
The above is merely one embodiment of the present invention; It or not whole or unique embodiment; The conversion of any equivalence that those of ordinary skills take technical scheme of the present invention through reading instructions of the present invention is claim of the present invention and contains.
Claims (9)
1. biochemical sensor based on CMUT; It is characterized in that: comprise first parts and second parts that are bonded together up and down; Said first parts comprise first monocrystalline silicon and the silica membrane layer (2) that forms in the first monocrystalline silicon upper surface oxidation; Said first monocrystalline silicon middle part is provided with cavity (8); This cavity runs through first monocrystalline silicon and terminates in the silica membrane layer on thickness direction, be disposed with the upper electrode layer (7) and the sensitive material layer (1) of metal at silica membrane layer (2) upper surface; Said second parts comprise silicon base (4) and silicon dioxide insulating layer (3); Said silicon base is provided with through hole (9) and groove (10) along thickness direction; The two connects on its thickness direction; Said silicon dioxide insulating layer (3) is arranged on the inside surface of silicon base (4) upper surface, lower surface and through hole and groove; The silicon dioxide insulating layer of silicon base upper surface (3) is provided with bottom electrode (5); This bottom electrode (5) comprises the metal film layer that is deposited on silicon dioxide insulating layer (3) upper surface and is deposited on the column in the through hole of through-silicon upper surface of substrate; Wherein, the metal film layer of said bottom electrode (5) does not cover whole silicon dioxide insulating layer fully but covers center line and the central lines of top electrode of metal film layer of center section and the bottom electrode of silicon dioxide insulating layer, and the silicon dioxide insulating layer that said first parts and second parts are positioned at the silicon base upper surface through the remaining part of first parts, first monocrystalline silicon and second parts carries out bonding and forms.
2. the biochemical sensor based on CMUT as claimed in claim 1 is characterized in that: said silica membrane layer (2) thickness range is 0.1 μ m～0.5 μ m, and effective vibration surface diameter range of silica membrane layer is 10 μ m～20 μ m.
3. the biochemical sensor based on CMUT as claimed in claim 1 is characterized in that: said first monocrystalline silicon middle part is provided with the remaining part in cavity (8) back and forms silicon pillar (6), and the width of this silicon pillar (6) highly is 2～5 μ m greater than 40 μ m.
4. the biochemical sensor based on CMUT as claimed in claim 1 is characterized in that: the height of said cavity (8) is 0.5～1.2 μ m.
5. the biochemical sensor based on CMUT according to claim 1: it is characterized in that: the thickness of the metal film layer of said bottom electrode (5) is 1～4 μ m; The lateral dimension of metal film layer is at least corresponding size half the of effective vibration film of silica membrane layer (2), and is at least 1 μ m with the lateral separation of the monocrystalline silicon internal face of first parts.
6. the biochemical sensor based on CMUT according to claim 1: it is characterized in that: said through hole (9) is used to bottom electrode (5) and the external world provides electrical connecting passage, and its through hole height is at least 40 μ m, and its through-hole diameter is 3～4 μ m.
7. the biochemical sensor based on CMUT according to claim 1: it is characterized in that: said top electrode covers whole silica membrane or covers the middle subregion of silica membrane.
8. the biochemical sensor based on CMUT according to claim 1: it is characterized in that: said silica membrane (2), top electrode (7), responsive identification material layer (1) form vibration film jointly, and the thickness of this vibration film is less than 1.5 μ m.
9. preparation method based on the biochemical sensor of CMUT is characterized in that: may further comprise the steps:
(1) get first monocrystalline silicon and with its upper and lower surfaces respectively oxidation form the silica membrane layer; Its lower surface silicon dioxide layer middle part of etching forms cavity graphical window; Expose monocrystalline silicon, etching is exposed to the monocrystalline silicon in the window and stops at its upper surface silicon dioxide layer, exposes the silicon dioxide layer on upper strata; Removal is positioned at the residue silicon dioxide layer of the first monocrystalline silicon lower surface and its lower surface is carried out chemically mechanical polishing then, forms first parts; Wherein, the zone that is etched in the middle part of first monocrystalline silicon forms cavity, and monocrystalline silicon partly forms the monocrystalline silicon pillar around the remaining cavity;
(2) get second monocrystalline silicon and its upper and lower surfaces oxidation formed the silica membrane layer; Etching silicon dioxide layer up and down makes it form graphical window respectively; Expose second monocrystalline silicon; Second monocrystalline silicon about etching is exposed in the graphical window is until perforation, and the zone that is etched at second monocrystalline silicon middle part this moment forms through hole and groove from top to bottom; Oxidation second monocrystalline silicon upper and lower surfaces and through hole and groove inside surface form complete silicon dioxide isolation layer; The chemically mechanical polishing second monocrystalline silicon upper surface silicon dioxide insulating layer; Deposit metallic material in this silicon dioxide insulating layer upper surface and through hole then; As bottom electrode, so far form second parts after the photoetching;
(3) under vacuum environment; Second parts that first parts that step (1) is obtained and step (2) obtain carry out bonding; Wherein, first parts are positioned at the top of second parts, and just the silicon pillar of first parts (6) is positioned on the silicon dioxide insulating layer of second parts, the second monocrystalline silicon upper surface; So, the silicon dioxide insulating layer of the second monocrystalline silicon upper surface is with the cavity sealing of first parts;
(4) the silica membrane upper surface at the first parts upper surface deposits the metal film layer as top electrode (7), and at metal film layer upper surface deposition sensitive material layer (1), photoetching is used for lead-in wire on sensitive layer at last.
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| CN103196577A (en) * | 2013-03-15 | 2013-07-10 | 西安交通大学 | Temperature sensor based on CMUT and preparation method and application method thereof |
| CN103675481A (en) * | 2013-10-18 | 2014-03-26 | 中国科学院电子学研究所 | Piezoelectric cantilever beam type mini electric field sensor |
| CN105073280A (en) * | 2013-02-27 | 2015-11-18 | 德克萨斯仪器股份有限公司 | Capacitive micromachined ultrasonic transducer (CMUT) with through-substrate via (TSV) substrate plug |
| CN106998522A (en) * | 2016-01-25 | 2017-08-01 | 中国科学院苏州纳米技术与纳米仿生研究所 | Micro- electric capacity sonac |
| CN107393981A (en) * | 2017-09-13 | 2017-11-24 | 李会欣 | Put backplane photovoltaic cell component, processing method and photovoltaic system deeply |
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| CN109561876A (en) * | 2018-10-24 | 2019-04-02 | 深圳市汇顶科技股份有限公司 | Ultrasonic transducer and its manufacturing method |
| CN110224682A (en) * | 2019-05-30 | 2019-09-10 | 西安交通大学 | CMUTsThe low-voltage impedance matching process and matching network of resonant mode biochemical sensor |
| WO2019214584A1 (en) * | 2018-05-10 | 2019-11-14 | 京东方科技集团股份有限公司 | Ultrasonic sensor and manufacturing method therefor, and ultrasonic sensor array and display device |
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| US9937528B2 (en) | 2013-02-27 | 2018-04-10 | Texas Instruments Incorporated | Capacitive micromachined ultrasonic transducer (CMUT) forming |
| CN105073280A (en) * | 2013-02-27 | 2015-11-18 | 德克萨斯仪器股份有限公司 | Capacitive micromachined ultrasonic transducer (CMUT) with through-substrate via (TSV) substrate plug |
| CN103196577B (en) * | 2013-03-15 | 2015-04-29 | 西安交通大学 | Temperature sensor based on CMUT and preparation method and application method thereof |
| CN103196577A (en) * | 2013-03-15 | 2013-07-10 | 西安交通大学 | Temperature sensor based on CMUT and preparation method and application method thereof |
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| CN106998522A (en) * | 2016-01-25 | 2017-08-01 | 中国科学院苏州纳米技术与纳米仿生研究所 | Micro- electric capacity sonac |
| CN107393981A (en) * | 2017-09-13 | 2017-11-24 | 李会欣 | Put backplane photovoltaic cell component, processing method and photovoltaic system deeply |
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| WO2019214584A1 (en) * | 2018-05-10 | 2019-11-14 | 京东方科技集团股份有限公司 | Ultrasonic sensor and manufacturing method therefor, and ultrasonic sensor array and display device |
| US11602771B2 (en) | 2018-05-10 | 2023-03-14 | Boe Technology Group Co., Ltd. | Ultrasonic sensor and manufacturing method therefor, and ultrasonic sensor array and display device |
| CN109561876A (en) * | 2018-10-24 | 2019-04-02 | 深圳市汇顶科技股份有限公司 | Ultrasonic transducer and its manufacturing method |
| CN109511023A (en) * | 2018-12-05 | 2019-03-22 | 武汉大学 | A kind of piezoelectric microphones and production method of high sensitivity |
| CN110224682A (en) * | 2019-05-30 | 2019-09-10 | 西安交通大学 | CMUTsThe low-voltage impedance matching process and matching network of resonant mode biochemical sensor |
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