CN104865001B - Micromechanics microminiature piezoresistive pressure sensor and its manufacture method - Google Patents

Abstract

The invention provides the method for manufacturing one or more microminiature piezoresistive pressure sensors in silicon wafer.The diaphragm of piezoresistive pressure sensor is that bond vitrified is formed.Piezoresistive pressure sensor can be formed by siliceous deposits, photoetching and etch process.

Description

Micromechanics microminiature piezoresistive pressure sensor and its manufacture method

Technical field

The invention mainly relates to micromechanics piezoresistive pressure sensor, more particularly to a kind of micromechanics of low pressure applications are extra small Type piezoresistive pressure sensor and its manufacture method, the sensor are that silicon fiml is formed on etched cavity using wafer bond techniques The method of piece and deep silicon etch determines the profile for the sensor to be manufactured.

Background technology

It is well known that in medical procedure, when to subject's vascular diagnostic or treating, the physiological parameter pinpointed in vivo is monitored The situation that subject can be directed to provides key message for medical professional.Blood pressure in coronary artery is exactly a spy Unimportant and beneficial physiological parameter.Research shows that the fixed point blood pressure in coronary artery can be used for calculating blood flow reserve Fraction（FFR）, blood flow reserve fraction（FFR）Represent coronary flow potential blood flow when being flowed toward coronary stenosis distal end Reduction.Decades-long clinical research shows, in angiography of coronary arteries operation and Heart catheterization operation, blood Stream deposit fraction（FFR）Identification that can be to the function severity of coronary artery stenosis provides qualitative assessment, so as to help doctor Further treatment needed for quantitatively judging.

Because coronary blood pipe diameter is very small, diameter can be less than 1 millimeter, possess a very small diagnostic device Most important to do fixed point blood pressure measurement, such diagnostic device will not have an impact to blood pressure and cause data distortion in itself. In this case, a kind of microminiature pressure sensor is arranged on a microminiature conveying equipment（Such as guiding wire）Distal end, Form sensor guiding wire component.By the way that the distal end of sensor guiding wire component is pushed into the predetermined of coronary artery Position, the microminiature pressure sensor of guiding wire distal end installation can be to carrying out pinpointing blood pressure survey in internal coronary artery Amount.The external diameter of sensor guiding wire component（OD）Typically 0.35 millimeter.Therefore need one kind to may be mounted at sensor to lead The miniature transducer of guide wire component remote.

It is accordingly obvious that ground, it is necessary to process a kind of micro pressure sensor, it can be arranged on conveying equipment（As led Silk）Distal end.In order to be about on 0.35mm guiding wire installed in external diameter by pressure sensor, the size of sensor must be It is less than on width in 0.3mm height and is less than 0.1mm.The pressure sensor for manufacturing this small size can be that one kind is chosen in volume production War.

The content of the invention

The invention discloses a kind of manufacture method of piezoresistive pressure sensor.More specifically, it discloses one kind The MEMS technology method for being used to manufacture piezoresistive pressure sensor after improvement, it includes the thin film being covered in above cavity Diaphragm simultaneously improves the sensitivity for the microminiature pressure sensor that may be mounted at guiding wire distal end using technique is strengthened.

One aspect of the present invention provides a kind of method for manufacturing piezoresistive pressure sensor, and it includes：First insulator is provided Silicon-on, it includes the first silicon layer deposited above the first block silicon layer in the first oxide layer；Second silicon-on-insulator is provided Structure, it includes the second silicon layer deposited above the second block silicon layer in the second oxide layer；By the first silicon layer and the second silicon layer face Opposite is combined together；Remove the second block silicon layer；Remove the second oxide layer, the second silicon layer of the second silicon on insulated substrate stays On the first silicon layer；The opening of one or more predetermined shapes and size is formed, so that the second silicon layer exposes a part； One or more openings of two silicon layers form one or more piezoresistors；Flower is shaped in the second silicon layer and the first silicon layer Groove groove, and terminate at the first oxide layer；Remove the first block silicon layer, so as to which piezoresistive pressure sensor is defined in into groove In the border of groove.By the manufacture method, can explication pressure sensor dimensions, it can by using photoetching technique and The trench portions of etching surround sensor to define the size of sensor and need not cut only can by applying mechanical force So that sensor to be discharged.

Second aspect of the present invention provides a kind of method for manufacturing piezoresistive pressure sensor, and it includes：First insulation is provided Body silicon-on, it includes the first silicon layer deposited above the first block silicon layer in the first oxide layer, on the body silicon knot Pattern cavity is formed on the surface of first silicon layer of structure；The second silicon on insulated substrate is provided, it is included on the second block silicon layer The second silicon layer deposited in the oxide layer of face second；First silicon layer and the second silicon layer are combined together face-to-face；Remove second piece Shape silicon layer；Remove the second oxide layer, the second silicon layer for leaving the second silicon on insulated substrate is covered in above the first silicon layer；Formed The opening of one or more predetermined shapes and size, the second silicon layer is set to expose a part；In the one or more of the second silicon layer Opening forms one or more piezoresistors；Decorative pattern groove is formed in the second silicon layer and the first silicon layer, and terminates at the One oxide layer；Remove the first block silicon layer, piezoresistive pressure sensor is formed in decorative pattern groove.Pass through the manufacture method, energy Enough explication pressure sensor dimensions, it can surround sensor completely to determine by using the groove of photoetching technique and etching The size of adopted sensor and need not cutting only is discharged sensor by the MEMS process cans of standard.

Third aspect present invention provides a kind of method for manufacturing piezoresistive pressure sensor, and it includes：First insulation is provided Body silicon-on, it includes the first silicon layer deposited above the first block silicon layer in the first oxide layer, on the surface of the first silicon layer Upper formation pattern cavity；The second silicon on insulated substrate is provided, it includes depositing in the second oxide layer above the second block silicon layer The second silicon layer；First silicon layer and the second silicon layer are combined together face-to-face；Remove the second block silicon layer；Remove the second oxidation Layer so that the second silicon layer of the second silicon on insulated substrate is covered on the first silicon layer of the first silicon on insulated substrate；Going After falling the second oxide layer, a silicon dioxide insulating layer is formed on the second silicon layer；Form one or more predetermined shapes and chi Very little opening, the second silicon layer is set to expose a part；One or more piezoelectricity are formed in one or more openings of the second silicon layer Resistor；Decorative pattern groove is formed in the second silicon layer and the first silicon layer, and terminates at the first oxide layer；Remove the first bulk silicon Layer, piezoresistive pressure sensor is formed in decorative pattern groove.

In addition, the present invention also provides a kind of micromechanics microminiature piezoresistive pressure sensor, it, which includes having, is deposited on the The first SOI wafer, the diaphragm of the first silicon layer in one oxide layer, the diaphragm include second with the second silicon layer SOI wafer, the diaphragm is by the second silicon layer and the aspectant combination of the first silicon layer and brilliant with the first silicon-on-insulator Piece is bonded together, and one or more openings are offered on the diaphragm, and one or more described openings make the second silicon layer expose one Part, there are one or more piezoresistors in one or more openings, a ditch is opened up in first silicon layer and the second silicon layer Groove, the depth of the groove terminate at the first oxide layer, and the groove limits the border of piezoresistive pressure sensor.

Brief Description Of Drawings

Specific method is described in detail in features described above of the present invention, brief overview above can by reference to example, wherein Some are had to show in the accompanying drawings.It should be understood that the accompanying drawing for the present invention representative instance, therefore should not by regarding For the limitation of its scope, because the present invention can allow other equivalent examples.

Figure 1A represents the top view of a typical piezoresistive pressure sensor.

Figure 1B represents the sectional view of pressure sensor shown in Figure 1A, and sectional view is splitted along Figure 1A 1A-1A' lines.

Fig. 2A and Fig. 2 B represent the first silicon-on-insulator（SOI）The sectional view of chip, it is as carrier wafer in its silicon Cavity is formed on layer..

What Fig. 3 was represented is the second silicon-on-insulator（SOI）The sectional view of chip, according to one embodiment of present invention, it Silicon layer be used for form diaphragm.

Shown in Fig. 4 is the structure that the first and second SOI wafer according to an embodiment of the invention is combined together.

What Fig. 5 was represented is the insulation according to an embodiment of the invention for removing support silicon wafer and the second SOI wafer Structure after layer.

What Fig. 6 A were represented is the piezoresistive transducer after piezoresistor according to an embodiment of the invention is formed Top view.

What Fig. 6 B were represented is the profile of piezoresistive transducer after piezoresistor shapes, and the profile is along Fig. 6 A 6A-6A' lines are splitted.

The step of what Fig. 7 and Fig. 8 was represented is the formation of piezoresistor.

Fig. 9 A to Figure 10 shows the forming step of the groove in one or more embodiments of the invention.

Figure 11 A and 11B reflect the bulk silicon for removing carrier S OI chips according to one or more embodiments of the invention The step of layer and insulating barrier and the release steps of piezoresistive transducer.

Embodiment

Several preferred embodiments according to invention are described in detail below in conjunction with accompanying drawing.

Figure 1A and Figure 1B reflects a kind of manufacture method for manufacturing micro pressure sensor and utilizes MEMS （MEMS）Technology completes the manufacture method of one or more piezoresistive pressure sensors 10.Shown in Figure 1A is a pressure resistance type The top view of pressure sensor.Shown in Figure 1B is the sectional view of piezoresistive pressure sensor.Figure 1B sectional view is along Figure 1A In 1A-1A' lines split.

Pressure sensor 10 covers cavity 11 by a diaphragm membrane 13 and formed above.Dotted line in Figure 1A represents The edge 16 of cavity 11 and the cavity area 11 therefore formed.Piezoresistor 12 is formed by diffusion or ion implanting The top of 11 inside diaphragm of cavity 13 is formed.When pressure is applied in the top of diaphragm 13, diaphragm 13 will deform and bending and Into cavity 11, cause the stress variation above piezoresistor 12 and change the resistance value of piezoresistor 12.

One key character parameter of pressure sensor is the sensitivity of sensor.For a given pressure change, Resistance change is bigger, then sensitivity is higher.The main target of pressure sensor design is to reach sensitivity as high as possible.

The sensitivity of above-mentioned piezoresistive pressure sensor is influenceed by the thickness of diaphragm 13.The thickness of diaphragm 13 is thinner, Then the sensitivity of pressure sensor is higher.However, the thickness of diaphragm 13 also has influence on the pressure limit that sensor can be surveyed.Diaphragm 13 is thinner, and before the resistance change of piezoresistor 12 is non-linear, the pressure that sensor can be surveyed is lower.Selection one is most It is beneficial that small thickness but sufficiently thick diaphragm 13, which are used for the fixed cavity 11 of matching size, so to be surveyed in equipment all In pressure limit, the change of piezoresistor resistance is linear.

The sensitivity of piezoresistive pressure sensor 10 is also influenceed by the size of cavity 11.Cavity 11 is bigger, pressure sensing Device 10 is then sensitiveer.When space is not a limiting factor, this is advantageous for the size for designing piezoresistive transducer, according to sky Chamber 11 can be sized to sufficiently large size to meet sensitivity requirement.When space is a limiting factor, such as Applied in heart and it is endovascular in the case of, the size of piezoresistive transducer, and the size of cavity 11, be designed to maximum The space of permission reaches the maximum sensitivity of sensor.

For in heart, the intervention of intravascular and percutaneous coronary（PCI）Application, preferably pressure sensor is installed In external diameter（OD）On about 0.35 millimeter of guiding wire, enter so there is no need to extra equipment and carry out Nanophene Hydrochloride in vivo Point measurement.In order to which above-mentioned piezoresistive pressure sensor is installed on guiding wire, the width of the pressure sensor has to Less than 0.3mm.Traditional MEMS technology including the equipment manufactured is separated to make using including the use of wafer coupons technique It is very challenging to make the piezoresistive transducer of above-mentioned this small size.First challenge is that size is too small, the semiconductor of standard Cutting equipment can not be handled.The semiconductor cutting equipment of standard is that the lateral dimension for being designed to processing any direction is not less than 1 millimeter of product.Therefore special equipment is needed to handle but will certainly so increase the cost of manufacture.Second challenge is to cut Error is cut, generally the cutting error of most cutting machine is 0.05mm on the market.In order to which the width that ensure final is less than 0.3mm, the width of product need to be less than 0.2mm, still also ensure to be less than 0.3 milli to reach its width after the error for counting cutting in Rice.If width is reduced to 0.2mm from 0.3mm, sensor area will be caused to reduce 33%, sensitivity can then reduce by 33%.

It is an object of the present invention to provide a kind of manufacture method of piezoresistive pressure sensor, the chi of the pressure sensor It is very little microminiature pressure resistance type pressure to be caused so as to eliminate the above mentioned uncertainty because of final products size with explication The problem of force snesor sensitivity declines.It is a further object to provide one kind can strengthen piezoresistive pressure sensor spirit The manufacture method and a kind of manufacture method that piezoresistive pressure sensor is manufactured only with semiconductor compatible technology of offer of sensitivity. And it is a further object to provide MEMS technological process, the technological process can be used for manufacture pressure during volume production Resistance pressure transducer, while the high excellent rate of low cost can be reached.

The manufacture method of piezoresistive pressure sensor has a detailed description in the accompanying drawings, and part typically all uses reference number in figure Code and letter represent that the diaphragm 13 of sensor is shaped by using bonding chip, and the size of sensor by photoetching and Etch process explication comes out.All accompanying drawings are merely to illustrate, and are not necessarily drawn to scale.

Wafer bonding technique is merged to define final pressure according to being used in the present invention under vacuum and etch process conditions The size of sensor, accompanying drawing 1 describe the production stage of piezoresistive pressure sensor to accompanying drawing 11.Manufacturing process starts from two Silicon-on-insulator is realized on chip（SOI）Structure.First SOI wafer 210, as shown in Figure 2 A, generally include block silicon layer 213 Carrier wafer as pressure sensor.First SOI wafer 210 is additionally included in an oxidation film layer above block silicon layer 213 212 and oxide layer 212 above a silicon layer 114.About 5 microns to 100 of the thickness of silicon layer 114 in first SOI wafer 210 Between micron.The silicon layer 114 of first SOI wafer 210 is used in the cavity 111 for producing pressure sensor.Including silicon layer 114, oxygen Change film layer 212 and block silicon layer 213 and a silicon-on-insulator is therefore formed on the first SOI wafer 210（SOI）Structure.

First, the cavity 111 of pressure sensor is being formed such as the first SOI wafer on carrier wafer.Due to wanting Cavity 111 is formd, silicon layer 114 is relatively thick.The thickness of silicon layer 114 in first SOI wafer 210 is not to influence pressure resistance type The key factor of the performance of pressure sensor 10, but if the limited height system of sensor 10, the thickness of silicon layer 114 will be less than The height limitation of completed sensor 10.The thickness of silicon layer 114 also contributes to the limit height of cavity 111, because cavity needs To be formed in the silicon layer 114 on the first SOI.

Application for low pressure, such as blood pressure is measured, cavity 111 simultaneously need not be very high.The height of usual cavity 111 is about It is enough between 2 microns to 50 microns.Therefore, about 5 microns of the thickness of silicon layer 114 in the first SOI wafer 210 arrives It can be used between 100 microns.

As shown in Figure 2 B, the shape of cavity 111 can shape in silicon layer 114.In general, photoetching technique is formed Light shield with opening forms the pattern of cavity 111 and shape.The shape of cavity 111, which determines, will form one or more pressures The region shape of electric resistor 112.Most widely used shape is square, rectangle, circle, but other shapes also have and made With.

After lithography, cavity 111 is formed using plasma etch techniques.The duration of plasma etching and energy Determine the height of cavity 111.The highly desirable thickness than silicon layer 114 of cavity 111 is much lower, is such as less than the thickness of silicon layer 114 Half.For being familiar with the personnel of MEMS technology process, they both know about forms cavity 111 in the first SOI wafer 210 Detailed step.In some cases, also can be directly using the SOI wafer for being ready for cavity 111

What Fig. 3 was represented is to form piezoresistive pressure sensor 10 using the second SOI wafer 220 to provide a thin silicone layer Diaphragm 13 an example.Second SOI wafer 220 generally includes block 213, oxide layers 222 of silicon layer and one Thin silicone layer 113, so as to form second soi structure.The thickness of silicon layer 113 can be as thin as it is about 0.5 micro- to 5 microns, for shape Into the diaphragm 13 of pressure sensor 10.

The thickness of the silicon layer 113 of second SOI wafer 220 determines the thickness of diaphragm 13.For a given cavity chi Very little, diaphragm 13 is thinner, and change of the pressure sensor to pressure is sensitiveer.On the other hand, the cavity chi given for identical Under very little, the diaphragm 13 of pressure sensor 10 is thinner, and the maximum pressure that it can bear is with regard to smaller.Generally, given for one Fixed cavity size, the thickness of diaphragm 13 is sufficiently thick, can bear the pressure sensor maximum pressure to be contacted, so that Reach maximum sensitivity in target pressure range.For microminiature pressure sensor, for example those are used for intravascular pressure Power is required to measure the blood pressure of sensitivity when monitoring, the thickness of diaphragm 13 can be between about 0.5 micron to 5 microns. Due to silicon layer 113 be for forming diaphragm 13, the silicon materials type of silicon layer 113 should select for the silicon materials class of piezoresistor 12 A kind of opposite material of type.

When p-type doping is used to form piezoresistor 12, band n-type doping silicon materials can be selected to form silicon layer 113.Similarly, when n-type doping is used to form piezoresistor 12, band p-type doping silicon materials can be selected to be formed Silicon layer 113.This is to limit the leakage that piezoresistor 12 arrives the substrate of diaphragm 13.What although this was not required, should be excellent Low-impedance silicon materials are first selected to form silicon layer 113.

Next, as shown in figure 4, the second SOI wafer 220 can be placed on above the first SOI wafer 210, make silicon layer 113 It is relative with silicon layer 114, that is, the position of the cavity 111 of carrier wafer 210.First SOI wafer 210 and the second SOI wafer 220 It is bonded together by using suitable technology, as melted wafer bonding under vacuum condition.If enter under very light pressure Row bonding, the cavity formed is vacuum-packed.In addition, other adhesive bonding methods, such as eutectic weldering, insulate available for the first silicon The bonding of body chip and the second SOI wafers.

After bonding and sealing, it is respectively adopted technique for grinding and etch process removes block silicon layer in the second SOI wafer 220 223 and oxide layer 222.Therefore, it is cavity above as shown in figure 5, the surface of the first SOI wafer 210 is only surplus silicon layer 113 111 and silicon layer 114.The first SOI wafer 210 and the second SOI wafer 220 are bonded using fusion technique is carried out under vacuum condition Together and remove the detailed process that silicon supports chip 223 and oxide layer 222, the personnel for being familiar with MEMS technology process know Road.Referring still to Fig. 5, in some cases, it is not necessary to remove oxide layer 222.If it is desired to if doing so, it can be used for not Some processes come.

And then, one or more piezoresistors 112 can be formed at the top of silicon layer 113.What Fig. 6 A were represented is one The top view of individual or multiple piezoresistors 112 piezoresistive transducer after formation above chip 250.What Fig. 6 B were represented is pressure The profile of piezoresistive transducer 10 after electric resistor 112 is formed, profile is splitted along Fig. 6 A 6A-6A' lines.

As shown in fig. 7, first, the thin layer of silicon dioxide insulating layer 261 precipitates to be formed at the top of silicon layer 113.Titanium dioxide The thickness of silicon insulating barrier can be in 1 microns.Second, form one or more with photoetching technique using the light shield with opening The pattern and shape of individual piezoresistor 112.

After the completion of photoetching, as shown in figure 8, the part of silica insulating barrier 261 positioned at open area is removed, so as to reveal Go out a part for silicon layer 113.Then, using diffusion or ion implantation technology technology, one is formed on the exposed surface of silicon layer 113 Or multiple piezoresistors 112.Correspondingly, the position of piezoresistor 112 is by the open area of silicon dioxide insulating layer 261 Determine, and should be in the range of the edge 116 of cavity 111 so that the sensitivity of pressure sensor is maximum.The edge 116 of cavity 111 Adopt and be represented by dashed line in fig. 6.If piezoresistor 112 is formed using ion implantation technology, in ion implantation process Afterwards high-temperature annealing process should be used to promote the ion of injection to enter in silicon and repaired due to silicon crystal caused by injection process Damage, the temperature of usual high-temperature annealing process is between 800 degrees Celsius to 1100 degrees Celsius.

Referring still to Fig. 6 A, it is therefore apparent that the quantity of piezoresistor 112 is not necessarily 4, even if having in the diagram 4 piezoresistances.In fact, the quantity of piezoresistor 112 can 1 arrive any quantity.

Referring still to Fig. 6 B and Fig. 7, in the case where the oxide membranous layer 222 of the second SOI wafer 220 does not remove, oxygen Changing layer 222 can directly use, and without depositing new oxide layer, therefore can skip on silicon dioxide insulating layer 261 Deposit a thin layer oxide layer the step.

And then, one or more grooves 281 are formed to define the border of pressure sensor 10.What Fig. 9 A were represented is first The top view of sensor 280, the groove at this moment formed have been enclosed in one or more piezoresistors above SOI wafer 210 112 surroundings.What Fig. 9 B were represented is the sectional view of chip 280 after groove 281 is formed.Sectional view in Fig. 9 B is along Fig. 9 A 9B-9B ' lines are splitted.What Fig. 9 C were represented is another sectional view of chip 280 after groove 281 is formed.Sectional view in 9C is along figure What the 9A-9A' lines on 9A were splitted.

First, using photoetching technique, groove 281 is formed using the light shield with opening.As long as the etching of groove 281 has been Complete to pass through oxide layer 261, silicon layer 113 and silicon layer 114, the width requirement of groove 281 is not very strict, can be several microns to hundreds of Micron.The border of groove 281 is in the outside at the edge 116 of cavity 111, and it is empty that some are left between groove 281 and cavity 111 Between 285, so that cavity 111 is unaffected.After groove 281 is formed, the silicon materials of the inside of space 281 will support silicon layer Diaphragm area on 113.Between between 285 need to be designed to certain width, to use the apparatus with pressure sensor 10 When, between being retained between silicon materials in 285 have sufficient intensity to bear any pressure.Between between 285 width be typically 5 microns and arrive 50 microns.

Referring still to Fig. 9 A, 9B and 9C, in one embodiment, groove 281 is not fully centered around sensor internal area In domain, therefore sensor 280 only has part and its surface is connected to by region 282, and it is thin that it may include silicon dioxide layer 261 A thin part, silicon layer 113 and silicon layer 114, as illustrated in figures 9a and 9b.In another embodiment as shown in Figure 10, groove 281 Can be entirely around the piezoresistive transducer region in sensor 280.

Region 282 connects together the periphery of the inside of pressure sensor and sensor 280, and its shape is preferably It is designed to be easier the shape being disconnected close to the edge of center sensor, to define the chi for the sensor being finally completed It is very little.A kind of method is that the shape in region 282 is designed into stepped cross, by trapezoidal broadside against the center away from sensor 280, Its narrow side is against the center of sensor 280.The ratio of the width on narrow side and the width of broadside is more preferably less than equal to 0.75.At this In the design of sample, when firmly discharging sensor 280 from the first SOI wafer 210 in subsequent step, narrow side will First break, therefore the size sensor of an explication can be obtained.

As long as the narrow side in region 282 it is sufficiently narrow so that be easy to disconnect by sensor 280 in subsequent step from first Separated in SOI wafer 210, its narrow hem width degree does not just have to require so strict.The narrow side design width in usual region 282 For 10 microns to 50 microns.The shape in region 282 is also not necessarily required to design in echelon, but whether which kind of shape, towards biography The width over there at sensor center is to be less than that hem width degree for being directed away from center sensor.The even quantity in region 282 Need not strictly control, and can with any quantity, such as, example as shown in Figure 9 A, it is possible to have two or 4 regions 282 are distributed in the both sides of chip 280 or surrounding.Further, even if saying that the best position in region 282 is in Wafer sensor 280 centre, as shown in the example of Fig. 9 A kinds, the position in region 282 is without strict control.

After the completion of photoetching, such as etch process can be used, removes part of silica insulating barrier 261, silicon layer 113 and opening Silicon layer 114 at region forms groove 281, and stops at the silicon dioxide layer 212 of the first SOI wafer 210.Once groove 281 pattern has been formed, and can use such as etch process, silicon dioxide insulating layer 261 is removed completely.In some situations Under, silicon dioxide insulating layer 261 can not have to remove, and it can be used for follow-up processing step.

Following step is to separate sensor 280 above the first SOI wafer 210.As shown in Figure 11 A one In individual embodiment, when groove 281 completely around around cavity 111 without forming region 282, the tool of the first SOI wafer 210 There is the side of one or more sensors 280, be attached to glue or other materials on backing material 290.Backing material 290 will One or more sensors 280 are maintained in the first SOI wafer 210, and then, the block silicon layer 213 in the first SOI wafer is gone Fall.

As shown in Figure 11 B, and then, the silicon dioxide layer 212 in the first SOI wafer 210 is removed.Silicon dioxide layer After 212 are removed, sensor 280 is only connected by glue or other materials with backing material 290.For example pass through UV-curing The method of change, the glue of connection sensor 280 can be removed, because glue material certain time under ultraviolet light just loses Viscous force.

Backing material 290 can be transparent material, such as glass or plastic material.Block silicon layer 230 and silicon dioxide layer After 212 remove, sensor device can be exposed under ultraviolet light, and is separated above backing material 290.Correspondingly, make The pressure sensor made need not cut can and be easy to separate above holding material 290.

In groove 281 not completely around in example as the sensor internal region residing for piezoresistor, Block silicon layer 213 and oxide layer 212 above one SOI wafer are etched after removing, and it is attached that region 282 is likely to remain in groove 281 Closely.It is region 282 that sensor now is maintained at into the sole material of good working condition, inward flange of the region close to center sensor Part is narrow.It is therefore possible to use instrument applying power sharp as knife goes to disconnect, and sensor can be with one One is separated.Because region 282 towards the inward flange of center sensor is directed away from the outside of sensor compared to region 282 Edge is shorter, when there is mechanical force application, will first break towards the inboard portion of center sensor, clearly demarcated so as to obtain a border Sensor.

From the foregoing, it will be observed that microminiature pressure sensor and energy explication size sensor can be manufactured by being provided with one kind here Method.In addition, there is further provided the method only with silicon compatible technology to manufacture pressure sensor.With manufacturing silicon diaphragm pressure drag The conventional method of formula sensor is compared, and the present invention has had the advantage that：（1）The size sensor being finally completed can be controlled accurately System, makes the sensitivity of sensor reach optimal.（2）After the completion of the height of sensor can accurately control.（3）It need not cut through Journey, the sensor can be separated by the compatible process of all semiconductors.

As described above, we are illustrated fully according to spirit of the invention, but the present invention is not limited to above-mentioned reality Apply example and implementation, the practitioner of correlative technology field can carry out different in the range of the technological thought license of the present invention Change and implementation.Although foregoing teachings are directed to embodiments of the invention, other and more examples of the present invention Go to be designed without departing from its base region, and its scope is determined by appended claim.

Claims (27)

1. a kind of method for manufacturing piezoresistive pressure sensor, it includes：The first silicon on insulated substrate is provided, it includes The first silicon layer deposited above one block silicon layer in the first oxide layer；The second silicon on insulated substrate is provided, it includes second piece The second silicon layer deposited above shape silicon layer in the second oxide layer；First silicon layer and the second silicon layer are combined together face-to-face；Go Fall the second block silicon layer；Remove the second oxide layer, the second silicon layer of the second silicon on insulated substrate is stayed on the first silicon layer；Formed The opening of one or more predetermined shapes and size, so that the second silicon layer exposes a part；At one or more of the second silicon layer Individual opening forms one or more piezoresistors；The mode of photoetching and etching is passed sequentially through in the second silicon layer and the first silicon layer Middle formation decorative pattern groove, and terminate at the first oxide layer；Remove the first block silicon layer, so as to which piezoresistive pressure sensor be limited In in the border of decorative pattern groove.

2. the method according to claim 1, it is characterised in that：The thickness of first silicon layer is 5 microns to 100 micro- Rice.

3. the method according to claim 1, it is characterised in that：The thickness of second silicon layer is 0.5 micron to 5 micro- Between rice.

4. the method according to claim 1, it is characterised in that：First silicon on insulated substrate, which has, is formed at the Pattern cavity in one silicon layer.

5. the method according to claim 1, it is characterised in that also include：First silicon layer of silicon structure on insulator A pattern cavity is formed on surface.

6. the method according to claim 4 or 5, it is characterised in that：Decorative pattern in second silicon layer and the first silicon layer Groove is arranged to part and surrounds the pattern cavity being located in the first silicon layer, stays subsequent region to be formed in second silicon surface One shape, in the shape that the region is formed on the surface, the inward flange in face of the pattern cavity deviates from pattern than region The outward flange of cavity is narrow.

7. the method according to claim 6, it is characterised in that：The width of the inward flange and the outward flange in the region Width ratio be less than or equal to 0.75.

8. the method according to claim 1, it is characterised in that：Decorative pattern groove in second silicon layer and the first silicon layer It is arranged to the pattern cavity being fully enclosed in the first silicon layer.

9. the method according to claim 1, it is characterised in that：One or more of piezoresistors are in the second silicon Formed in opening on layer by the method for diffusion.

10. the method according to claim 1, it is characterised in that：One or more of piezoresistors are in the second silicon Formed in opening on layer by the method for ion implanting.

11. the method according to claim 1, it is characterised in that also include：Shape on second silicon layer after second oxide layer is removed Into silicon dioxide insulating layer.

12. the method according to claim 11, it is characterised in that：The silicon dioxide insulating layer is on the second silicon layer One or more openings on form one or more piezoresistors before remove.

13. the method according to claim 11, it is characterised in that：The silicon dioxide insulating layer is on the second silicon layer Do not remove before forming one or more piezoresistors in one or more opening.

14. the method according to claim 1, it is characterised in that：First silicon layer bag of first silicon on insulated substrate Material containing p-type silicon, second silicon layer include a n type silicon materials.

15. the method according to claim 1, it is characterised in that：First silicon layer bag of first silicon on insulated substrate N-type silicon material is included, second silicon layer includes p type silicon materials.

16. the method according to claim 1, it is characterised in that also include：Remove again after removing the described first block silicon layer Second oxide layer.

17. according to the method for claim 5, it is characterised in that：The thickness of first silicon layer is 5 microns to 100 micro- Between rice.

18. according to the method for claim 5, it is characterised in that：The thickness of second silicon layer is 0.5 micron to 5 micro- Between rice.

19. a kind of method for manufacturing piezoresistive pressure sensor, it includes：The first silicon on insulated substrate is provided, it includes The first silicon layer deposited above one block silicon layer in the first oxide layer, pattern cavity is formed on the surface of the first silicon layer；There is provided Second silicon on insulated substrate, it includes the second silicon layer deposited above the second block silicon layer in the second oxide layer；By the first silicon Layer and the second silicon layer are combined together face-to-face；Remove the second block silicon layer；Remove the second oxide layer so that on the second insulator Second silicon layer of silicon structure is covered on the first silicon layer of the first silicon on insulated substrate；Second after the second oxide layer is removed A silicon dioxide insulating layer is formed above silicon layer；The opening of one or more predetermined shapes and size is formed, makes the second silicon layer sudden and violent Expose a part；One or more piezoresistors are formed in one or more openings of the second silicon layer；Pass sequentially through photoetching Decorative pattern groove is formed in the second silicon layer and the first silicon layer with the mode of etching, and terminates at the first oxide layer；Remove first piece Shape silicon layer, piezoresistive pressure sensor is formed in decorative pattern groove.

A kind of 20. micromechanics microminiature piezoresistive pressure sensor, it is characterised in that：It, which includes having, is deposited on the first oxide layer On the first silicon layer the first SOI wafer, diaphragm, the diaphragm include with the second silicon layer the second insulator on Silicon wafer, the diaphragm are bonded in by the second silicon layer with the aspectant combination of the first silicon layer with the first SOI wafer Together, one or more openings are offered on the diaphragm, one or more described openings make the second silicon layer expose a part, one Or there are one or more piezoresistors in multiple openings, pass sequentially through photoetching and etching in first silicon layer and the second silicon layer Mode open up a groove, the depth of the groove terminates at the first oxide layer, and the groove limits piezoresistive pressure sensor Border.

21. the piezoresistive pressure sensor according to claim 20, it is characterised in that：A cavity is opened up on first silicon layer, The membrane covered is on the cavity.

22. the piezoresistive pressure sensor according to claim 20, it is characterised in that：On the surface of first silicon layer A cavity is opened up, the membrane covered is on the cavity.

23. the piezoresistive pressure sensor according to claim 21 or 22, it is characterised in that：Second silicon layer and Groove in one silicon layer is arranged to part and surrounds the cavity being located in the first silicon layer, stays subsequent region in second silicon surface One shape of upper composition, in the shape that the region is formed on the surface, the inward flange ratio in face of the cavity deviates from pattern cavity Outward flange it is narrow.

24. the piezoresistive pressure sensor according to claim 20, it is characterised in that：The thickness of first silicon layer is 5 micro- Rice is to 100 microns.

25. the piezoresistive pressure sensor according to claim 20, it is characterised in that：The thickness of second silicon layer is Between 0.5 micron to 5 microns.

26. the piezoresistive pressure sensor according to claim 23, it is characterised in that：The width of the inward flange and institute The ratio for stating the outer peripheral width in region is less than or equal to 0.75.

27. the piezoresistive pressure sensor according to claim 21 or 22, it is characterised in that：Second silicon layer and Groove in one silicon layer is arranged to the cavity being fully enclosed in the first silicon layer.