CN105785073B - A kind of piezoresistance type acceleration sensor and preparation method thereof - Google Patents
A kind of piezoresistance type acceleration sensor and preparation method thereof Download PDFInfo
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- CN105785073B CN105785073B CN201410815643.1A CN201410815643A CN105785073B CN 105785073 B CN105785073 B CN 105785073B CN 201410815643 A CN201410815643 A CN 201410815643A CN 105785073 B CN105785073 B CN 105785073B
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Abstract
The present invention provides a kind of piezoresistance type acceleration sensor and preparation method thereof, the improvement of the sensor is sensitive structure part, mutually independent each four sensitive beams are symmetrically arranged at left and right sides of mass block in sensitive structure, set a force sensing resistance in each sensitive beam；The two sides of four sensitive beams respectively set the supporting beam for being used to support mass block, and force sensing resistance is produced in independent sensitive beam to the width that can reduce sensitive beam, to be substantially reduced influence of the sensitive beam to the structure coefficient of stiffiness, obtain the highly sensitive and high figure of merit；For sensitive beam close to mass block midline position, flexure is smaller, can reduce paraxonic sensitivity.For supporting beam close to quality block edge, the arm of force is long, and mass block caused by paraxonic acceleration can preferably be inhibited to reverse.Upper surface of support beam is lower, surface non-oxidation layer, can reduce structural deflection caused by oxidation ply stress.Sensitive cantilever thickness is greater than supporting beam, it can be achieved that stress is concentrated, to improve sensitivity and the figure of merit.
Description
Technical field
The present invention relates to a kind of piezoresistance type acceleration sensors and preparation method thereof, utilize different thickness more particularly to a kind of
The supporting beam and sensitive beam of degree are come the piezoresistance type acceleration sensor and preparation method thereof that improves sensor performance.
Background technique
Micro-mechanical accelerometer is microcomputer electricity integrated system (Micro Electro Mechanical Systems, MEMS)
One of pillar product of technical field, small, the at low cost, high reliability with size, in consumer electronics product, vapour
The fields such as vehicle electronics, Industry Control and national defence have a wide range of applications.Micro-mechanical accelerometer can be divided into pressure by testing principle again
Resistive, piezoelectric type, tunnel type, condenser type etc..Wherein, resistance-type accelerometer have interface circuit simple, strong antijamming capability,
The advantages that processing technology is simple.
Body micro mechanical technology is the common method for making piezoresistance type acceleration sensor.Body micromechanics piezoresistance type acceleration passes
Sensor uses sandwich structure.So-called sandwich structure is made of three-decker: upper cover plate, movable sensitive structure and lower cover plate.
Wherein movable sensitive structure uses beam-mass block structure, i.e., supports mass block structure by several beam, and the quick electricity of power is made on beam
Resistance, when there is acceleration, mass block, which generates displacement, bends beam, to generate stress on beam, is answered by force sensing resistance measurement
Acceleration value just can be obtained in power.Upper and lower cover plates provides protection for movable structure, and position limiting structure is also made in upper and lower cover plates, limitation
The displacement of mass block, avoids structural failure when high overload.
Sensitivity and bandwidth are to characterize the important indicator of the static characteristic and dynamic characteristic of acceleration transducer respectively.But
It is that there are contradictions for requirement of the two indexs to structure.In general, the structure coefficient of stiffiness is smaller, mass block quality is bigger, then
Sensitivity is higher, bandwidth is lower；On the contrary, the structure coefficient of stiffiness is bigger, mass block quality is smaller, then sensitivity is lower, bandwidth more
It is high.Therefore, the figure of merit generally using the product of sensitivity and bandwidth as acceleration transducer.The figure of merit is higher, then comprehensive performance
Better.
For piezoresistance type acceleration sensor, sensitivity is directly proportional to beam upper surface maximum stress, bandwidth and mesomerism
Circular frequency is directly proportional, therefore the product of beam upper surface maximum stress and resonant frequency can be used as the figure of merit S of sensitive structureTf。
For two-end fixed beam-mass block structure sensitive structure, figure of merit STfIt is approximate with mass block and the square root of beam volume ratio at
Direct ratio:
Since the minimum dimension of beam is determined by process conditions, it is difficult to reduce.When size sensor reduces, figure of merit STfAlso subtract
It is small.More seriously, resonant frequency increases with structure scaled down, when size sensor reduces, in order to guarantee spirit
Sensitivity and resonant frequency are in the reasonable scope, it is necessary to which the appropriate size for increasing beam causes figure of merit STfIt further decreases.Therefore, excellent
Change sensitive structure to improve the S of structureTfThe figure of merit is a challenge of acceleration transducer design.
Another design difficulty of acceleration transducer is the inhibition to paraxonic sensitivity.Acceleration is vector, there is x, y
With tri- components of z, ideally single-axis acceleration sensors should be only sensitive to one-component, but practical devices are generally to three
A component is sensitive, as far as possible inhibit to the sensitivity (paraxonic sensitivity) for not needing component be sensor design another master
Want problem.
The Stress match of sensitive structure is also the design difficulty of acceleration transducer.Beam mass block sensitive structure is quick to stress
Sense.When beam surface is there are when oxide layer, the thermal stress in oxide layer can cause structure to have the flexure of micron dimension, cause device
Performance decline is even failed.Common method is first Liang Qu to be thinned with bulk silicon micromachining technology, then make force sensing resistance, this
Sample can form symmetrical oxide layer in structure upper and lower surface, realize Stress match.But this method and integrated circuit technology
Poor compatibility.General integrated circuit factory does not provide bulk silicon micromachining service, does not allow to have been carried out bulk silicon micromachining yet
Silicon wafer enters factory.Therefore ideal processing flow is first to carry out the processing of force sensing resistance electric bridge in integrated circuit foundries, so
After carry out bulk silicon micromachining.And the process must solve the problems, such as Stress match from structure.
Summary of the invention
In view of the foregoing deficiencies of prior art, the purpose of the present invention is to provide a kind of piezoresistance type acceleration sensors
And preparation method thereof, the figure of merit for solving acceleration transducer in the prior art is low and sensitive anti-to being easy to generate paraxonic
The problem of answering and the difficulty for overcoming conventional acceleration sensor Stress match difference.
In order to achieve the above objects and other related objects, the present invention provides a kind of piezoresistance type acceleration sensor, the pressure
Resistive acceleration transducer includes at least: sensitive structure；It is bonded to the positive upper cover plate of the sensitive structure and its back side respectively
Lower cover plate；The sensitive structure include: rectangle outer rim, in the rectangle outer rim center mass block；It is described
Mass block relative to the rectangle outer rim two groups of opposite side respectively symmetrically；The mass block is respectively arranged on the left side and the right side two
The supporting beam fixed and be connected between the mass block and rectangle outer rim；Two of every side at left and right sides of the mass block
Four sensitive beams being connected between the mass block and the rectangle outer rim are respectively provided between the supporting beam；It is described quick
Sense beam, mass block and the respective upper surface of rectangle outer rim are generally aligned in the same plane；The sensitive beam supporting beam more collects
In be distributed near the central axis of the mass block in left-right direction；Four sensitivities positioned at described mass block the same side
Beam, it is symmetrical about the central axis of the mass block each other for one group two-by-two；The head of each sensitive beam or
Tail portion is respectively equipped with a force sensing resistance；Power with the central axis distance of the mass block in four nearest sensitive beams
Position consistency of the quick resistance in respective sensitive beam；Four farthest sensitive beams with the central axis distance of the mass block
On position consistency of the force sensing resistance in respective sensitive beam；The supporting beam and the respective lower surface of the sensitive beam are located at same
The upper surface of one plane and the supporting beam is lower than the upper surface of the sensitive beam；The width of the sensitive beam is much smaller than the branch
Support the width of beam；Each sensitive beam is equipped with the metal lead wire for connecting force sensing resistance both ends in the sensitive beam；The sensitivity
The width of beam is slightly wider than the width of the force sensing resistance and metal lead wire.
Preferably, the power in four sensitive beams nearest with the central axis of mass block distance is quick
Resistance is located at the head position close to each sensitive beam of the mass block；The central axis with the mass block is apart from most
The force sensing resistance in remote four sensitive beams is located remotely from the tail position of each sensitive beam of the mass block.
Preferably, the power in four sensitive beams nearest with the central axis of mass block distance is quick
Resistance is located remotely from the tail position of each sensitive beam of the mass block；It is farthest with the central axis distance of the mass block
Four sensitive beams on the force sensing resistance be located at close to the mass block each sensitive beam head position.
Preferably, the upper surface of the sensitive beam is equipped with oxide layer；The upper surface non-oxidation layer of the supporting beam.
Preferably, the upper cover plate and lower cover plate are bonded to the upper and lower surfaces of the rectangle outer rim respectively；Institute
State the buffer stopper for being equipped with below mass block the gap between the lower cover plate and being located at the lower cover plate.
The present invention also provides a kind of production method of piezoresistance type acceleration sensor, which is included at least: (1) mentioning
The force sensing resistance is made for a silicon base, and in the front of the silicon base；(2) distinguish in the front and back of the silicon base
Make corrosion barrier layer；(3) corrosion barrier layer of the silicon substrate bottom back side is etched until exposing the silicon substrate bottom back side,
Form corrosion window；(4) corrode the silicon substrate bottom back side until the thickness of the remaining silicon fiml of corrosion area along the corrosion window
Until thickness for the sensitive beam, the back side of the sensitive structure is formed, the part that is not corroded forms the mass block；
(5) metal lead wire at the force sensing resistance both ends is connected in the front production of the sensitive structure；(6) under production is described
Cover board and the back side that the lower cover plate is bonded to the sensitive structure；(7) the positive gold of the silicon base is thinned in etching
Belong to lead two sides, forms concave regions, the thickness with a thickness of the supporting beam of the concave regions；(8) silicon substrate is penetrated
Bottom front forms the sensitive knot being made of the rectangle outer rim, supporting beam, sensitive beam and the mass block that are separated from each other
The front of structure；(9) it makes the upper cover plate and the upper cover plate is bonded to the front of the sensitive structure, outside the rectangle
The piezoresistance type acceleration sensor is formed after frame scribing.
Preferably, the corrosion barrier layer in the step (2) is silica, silicon nitride composite layer.
Preferably, the corrosive liquid of the corrosion silicon substrate bottom back side is alkaline anisotropic corrosive liquid in the step (4).
Preferably, the alkaline anisotropic corrosive liquid includes KOH, TMAH corrosive liquid.
Preferably, etching is thinned the method that the metal lead wire two sides form the concave regions and is in the step (7)
Deep reaction ion etching method；It is deep reaction ion etching method that the positive method of the silicon base is penetrated in the step (8).
As described above, piezoresistance type acceleration sensor and preparation method thereof of the invention, has the advantages that this hair
Bright use is wide and thin supporting beam and narrow and thick sensitive beam support mass block jointly, big using narrow and thick sensitive beam the moment of inertia
The characteristics of realize that stress is concentrated, be significantly reduced influence of the sensitive beam to the structure coefficient of stiffiness to improving the figure of merit.By sensitive beam
It is produced on structure middle line nearby and electric bridge connection type is combined to realize the inhibition to paraxonic sensitivity.Sensitive beam flexure of the invention
It is smaller, it can reduce paraxonic sensitivity；For supporting beam close to quality block edge, the arm of force is long, preferably paraxonic can be inhibited to accelerate
Mass block caused by spending is reversed around middle line；Upper surface of support beam is lower than mass block and frame, and surface does not have oxide layer, can subtract
Structural deflection caused by small oxidation ply stress.The thickness of supporting beam is thin, can reduce the structure coefficient of stiffiness, improves sensitivity and excellent
Value.
Detailed description of the invention
Fig. 1 is shown as piezoresistance type acceleration sensor sensitive structure schematic diagram of the invention.
Fig. 2 is shown as sensitive structure schematic top plan view of the invention.
Fig. 3 is shown as the connection schematic diagram of metal lead wire and force sensing resistance of the invention.
Fig. 4 is shown as the electric bridge connected mode schematic diagram of force sensing resistance of the invention.
Fig. 5 a to Fig. 5 e is shown as the production process structural schematic diagram of piezoresistance type acceleration sensor of the invention.
Component label instructions
11 upper cover plates
12 lower cover plates
101 rectangle outer rims
102 mass blocks
103 supporting beams
104 sensitive beams
105 force sensing resistances
106 metal lead wires
13 silicon bases
131 corrosion barrier layers
Specific embodiment
Illustrate embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this specification
Other advantages and efficacy of the present invention can be easily understood for disclosed content.The present invention can also pass through in addition different specific realities
The mode of applying is embodied or practiced, the various details in this specification can also based on different viewpoints and application, without departing from
Various modifications or alterations are carried out under spirit of the invention.
Please refer to Fig. 1 to Fig. 5 e.It should be noted that diagram provided in the present embodiment only illustrates this in a schematic way
The basic conception of invention, only shown in schema then with related component in the present invention rather than package count when according to actual implementation
Mesh, shape and size are drawn, when actual implementation kenel, quantity and the ratio of each component can arbitrarily change for one kind, and its
Assembly layout kenel may also be increasingly complex.
The piezoresistance type acceleration sensor of the invention includes at least: sensitive structure, upper cover plate and lower cover plate, it is described on
Cover board is bonded in the front of the sensitive structure, and the lower cover plate is bonded in the back side of the sensitive structure.As shown in Figure 1, Fig. 1
It is shown as piezoresistance type acceleration sensor sensitive structure schematic diagram of the invention.The sensitive structure in the present embodiment includes:
Rectangle outer rim 101, mass block 102, as shown in Figure 1, during the mass block 102 is located inside the rectangle outer rim 101
Heart position, and the mass block 102 relative to the rectangle outer rim 101 two groups of opposite side respectively symmetrically；Preferably, described
The cross section of mass block 102 be rectangle, as shown, two groups of opposite side of 102 cross section of the mass block respectively with the rectangle
Two groups of opposite side of outer rim 101 are parallel.Preferably, the upper cover plate 11 is bonded to the rectangle outer rim with lower cover plate 12 respectively
101 upper and lower surfaces.The sensitive structure further includes supporting beam 103, as shown in Figure 1, the left and right of the mass block 102
The supporting beam 103 that two sides are respectively equipped with two fixations and are connected between the mass block 102 and rectangle outer rim 101, it is described
Respectively symmetrically, example is as shown in figure 1, described for two supporting beams 103 of the every side of mass block 102 and two supporting beams 103 of the other side
The supporting beam 103 of the 102 right side top of supporting beam 103 and mass block of 102 left side top of mass block is on same straight line, and
Middle line (dotted line in Fig. 1) of the straight line parallel in the mass block 102 in left and right directions；The support of 102 lower left of mass block
The supporting beam 103 of beam 103 and 102 lower right of mass block is in same straight line, and the straight line is also parallel with the mass block 102 on a left side
The middle line of right direction.
The sensor of the invention further includes the sensitive beam 104 being set between the supporting beam 103, such as Fig. 1 institute
Show, is respectively provided with four between two supporting beams 103 of the 102 every side in the left and right sides of mass block and is connected to the quality
Sensitive beam 104 between block 102 and the rectangle outer rim 101, two supporting beams positioned at 102 left side of mass block
Four sensitive beams 104 between 103 are spaced each other parallel arranged, and four sensitive beams 104 are in same plane；Equally
Four sensitive beams 104 between two supporting beams 103 on 102 right side of mass block are spaced each other parallel arranged, and four
A sensitive beam 104 is in same plane.As shown in Figure 1, in the present invention, the sensitive beam 104, mass block 102 and
The respective upper surface of rectangle outer rim 101 is generally aligned in the same plane.In the present invention, described in described 102 the same side of mass block
Center (void in Fig. 1 of the more integrated distribution of supporting beam 103 of sensitive beam 104 in the mass block 102 in left-right direction
Line) near axis；It is somebody's turn to do that is, the distance between being located at four sensitive beams 104 in 102 left side of mass block is less than
The distance between sensitive beam 104 at 102 upper left supporting beam 103 position adjacent thereto of mass block is located at the mass block
The distance of sensitive beam 104 at the position adjacent thereto of supporting beam 103 of 102 lower lefts is equal to the upper left support of mass block 102
The distance between sensitive beam 104 at the position adjacent thereto of beam 103, the supporting beam 103 and sensitive beam on 102 right side of mass block
Positional relationship between 104 and each sensitive beam 104 is also such.And between the mass block 102 and the sensitive beam 104
Positional relationship are as follows: four sensitive beams 104 positioned at described 102 the same side of mass block, two-by-two for one group each other about institute
The central axis (dotted line in Fig. 1) for stating mass block 102 is symmetrical.It is preferably located at 102 left side of mass block
Each sensitive beam 104 is parallel to each other and the distance between adjacent sensitive beam 104 is equal to each other, and is located at 102 right side of mass block
Four sensitive beams 104 between positional relationship be also in this way, and being located at the sensitive beam in 102 left side of the mass block
104 is symmetrical with the sensitive beam 104 positioned at 102 right side of mass block.
As shown in Fig. 2, Fig. 2 is shown as sensitive structure schematic top plan view of the invention.Each sensitive beam of the invention
104 head or tail portion are respectively equipped with a force sensing resistance 105, and the central axis with the mass block 102 is (in Fig. 1
Dotted line) position consistency of the force sensing resistance 105 in respective sensitive beam 104 in four nearest sensitive beams 104 of distance；With it is described
Force sensing resistance 105 in four farthest sensitive beams 104 of the central axis distance of mass block 102 is in respective sensitive beam 104
On position consistency, that is to say, that in Fig. 2, in the sensitive beam 104 in 102 left side of the mass block, wherein most intermediate
Force sensing resistance 105 in two sensitive beams 104 and the most intermediate (center in the bright sensitive beam 104 on 102 right side of mass block
Axis both sides) two sensitive beams 104 on position consistency of the force sensing resistance 105 in respective sensitive beam 104；It is similarly positioned in
Force sensing resistance 105 in two sensitive beams 104 at 102 left side most edge (adjacent with the supporting beam 103) of the mass block with
Position of the force sensing resistance 105 in the respective sensitive beam 104 in 102 most marginal two sensitive beams 104 in right side of mass block
Unanimously.What the so-called position in the sensitive beam 104 indicated is head or the tail positioned at the sensitive beam 104 in the present embodiment
Portion, head refer to the sensitive beam 104 close to one end of the mass block 102, and tail portion refers to the sensitive beam 104 and the square
One end that shape outer rim 101 connects.
A preferred embodiment of the present invention is, as shown in Fig. 2, most with the central axis distance of the mass block 102
(most intermediate each two sensitive beams 104 positioned at 102 left and right sides of mass block) is described in close four sensitive beams 104
Force sensing resistance 105 is located at the head position close to each sensitive beam 104 of the mass block 102；With the institute of the mass block 102
State four sensitive beams 104 of central axis distance farthest (each two sensitive beams 104 of 102 left and right sides edge of mass block)
On the force sensing resistance 105 be located remotely from the mass block 102 each sensitive beam 104 tail position.Of the invention is another
Kind preferred embodiment is that nearest four sensitive beams 104 (are located at matter with the central axis distance of the mass block 102
Most intermediate each two sensitive beams 104 of the left and right sides of gauge block 102) on the force sensing resistance 105 be located remotely from the mass block
The tail position of 102 each sensitive beam 104；With the farthest (mass block 102 of central axis distance of the mass block 102
Each two sensitive beams 104 of left and right sides edge) four sensitive beams 104 on the force sensing resistance 105 be located at it is close
In the head position of each sensitive beam 104 of the mass block 102.Preferably simultaneously, there is oxidation in the upper surface of the sensitive beam 104
Layer covering；The upper surface non-oxidation layer of the supporting beam 103 covers.
As shown in Figure 1, the supporting beam 103 is generally aligned in the same plane and described with the respective lower surface of the sensitive beam 104
The upper surface of supporting beam 103 is lower than the upper surface of the sensitive beam 104；The width of the sensitive beam 104 is much smaller than the support
The width of beam 103；As shown in figure 3, Fig. 3 is shown as the connection schematic diagram of metal lead wire 106 and force sensing resistance 105 of the invention.
Each sensitive beam 104 is equipped with the metal lead wire 106 for connecting 105 both ends of force sensing resistance in the sensitive beam 104；The sensitivity
The width of beam 104 is slightly wider than the width of the force sensing resistance 105 and metal lead wire 106.
Each force sensing resistance 105 is interconnected to form electric bridge in the present invention, as shown in figure 4, Fig. 4 is shown as power of the invention
The electric bridge connected mode schematic diagram of quick resistance 105.In Fig. 2, each force sensing resistance 105 is indicated with R1 to R8, wherein being located at described
Four force sensing resistances 105 in 102 left side of mass block are represented sequentially as R1, R2, R1, R5 from top to bottom；Positioned at the mass block 102
Four force sensing resistances 105 on right side are represented sequentially as R4, R3, R7, R8 from top to bottom.Each force sensing resistance 105 connects into
Electric bridge it is as shown in Figure 4: wherein R2, R7, R8, R1 are mutually concatenated；R5, R4, R3, R6 mutually concatenate (each force sensing resistance 105
Tandem is concatenated by the metal lead wire 106 being located in respective sensitive beam 104), R2 and R5 are interconnected in power supply
Voltage；R1 and R6 is connected with each other and is grounded；Output end is equipped between R7 and R8 simultaneously, output end is equipped between R4 and R3.
Two output ends are for measuring output voltage.
The working principle and working method of the piezoresistance type acceleration sensor of the invention are as follows: assuming that the mass block
102 by the acceleration vertical with its surface；Sensitive beam 104 is described each so as to cause being located at by stress due to acceleration
The variation of resistance value occurs for force sensing resistance 105 in sensitive beam 104, due to increased resistance value and the ratio of former resistance value with by
Stress it is directly proportional, and stress can directly reflect suffered acceleration magnitude；Therefore, the size of increased resistance value can be straight
Connect the size for reflecting acceleration.And actual conditions are, mass block 102 is generally not the acceleration by its vertical surface merely
Degree, and actually acceleration in the horizontal direction also can be important, therefore, in order to offset acceleration transducer to the sensitive of paraxonic
Degree, each force sensing resistance 105 design electric bridge connection method as described above, which can offset the piezoresistance type acceleration
The acceleration of sensor in the horizontal direction only calculates the effective acceleration in vertical direction.As previously mentioned, force sensing resistance 105
Change in resistance can directly reflect the size of normal acceleration, therefore in test electric bridge two output ends voltage change
It can directly reflect the variation of resistance, that is, the voltage change of two tested out output end can be directly changed into vertically
The size of acceleration on direction.
The present invention also provides the production method based on piezoresistance type acceleration sensor described above, in the present embodiment, the system
Make method the following steps are included: Fig. 5 a to Fig. 5 d is shown as piezoresistance type acceleration sensing of the invention as shown in Fig. 5 a to Fig. 5 d
The production process structural schematic diagram of device.
Step 1: as shown in Figure 5 a, a silicon base 13 is provided, and make the quick electricity of power in the front of the silicon base 13
Resistance 105；The force sensing resistance 105 of production is eight force sensing resistances 105 as shown in Figure 2.
Step 2: in Fig. 5 a, corrosion barrier layer 131 is made respectively in the front and back of the silicon base 13, it is preferable that institute
Stating corrosion barrier layer 131 is silica, silicon nitride composite layer.
Step 3: the corrosion barrier layer 131 at 13 back side of silicon base is etched to exposing 13 back side of silicon base
Until, form corrosion window.
Then implementation steps four: as shown in Figure 5 b, corrode 13 back side of silicon base until corrosion along the corrosion window
Until the thickness with a thickness of the sensitive beam 104 of the remaining silicon fiml in region, the back side of the sensitive structure is formed, it is not rotten
Erosion part forms the mass block 102；Preferably, corrode the corrosive liquid at 13 back side of silicon base as alkaline anisotropic corrosion
Liquid.It is further preferred that the alkaline anisotropic corrosive liquid includes the corrosive liquids such as KOH, TMAH in the present embodiment, the present invention
The alkaline anisotropic corrosive liquid used is not limited to KOH, TMAH corrosive liquid, other remove the various alkali of KOH, TMAH corrosive liquid
Property anisotropic etchant is also all fallen within scope of the present invention.
Step 5: as shown in Figure 5 c, 105 both ends of force sensing resistance are connected in the front production of the sensitive structure
The metal lead wire 106, the width of made metal lead wire 106 is as shown in figure 3, the width of the metal lead wire 106 of production is answered
Less than the width of the sensitive beam 104.Then implementation steps six: as fig 5d, under making the lower cover plate 12 and will be described
Cover board 12 is bonded to the back side of the sensitive structure, it is preferable that the sky between 102 lower section of mass block and the lower cover plate 12
Gap is equipped with the buffer stopper positioned at the lower cover plate 12.The effect of the lower cover plate 12 is to provide protection for the sensitive structure, institute
The effect for stating buffer stopper is in the case of limiting high overload, and the displacement of mass block 102 is too big, avoids structural failure.
Step 7: positive 106 two sides of metal lead wire of the silicon base 13 are thinned in etching, form concave regions, institute
State the thickness with a thickness of the supporting beam 103 of concave regions silicon, that is to say, that as shown in Figure 1, the supporting beam 103 is upper
Surface will be lower than the upper surface of the sensitive beam 104, while the corrosion barrier layer 131 of 103 upper surface of the supporting beam is etched
And remove, therefore, 103 upper surface of supporting beam is covered without oxide layer, and 104 upper surface of the sensitive beam is not due to having
It is etched, therefore, the upper surface of the sensitive beam 104 is equipped with oxide layer.It is further preferred that the metal lead wire is thinned in etching
The method that 106 two sides form the concave regions is deep reaction ion etching method.
Step 8: 13 front of silicon base is penetrated, the rectangle outer rim 101, the supporting beam by being separated from each other are formed
103, the front for the sensitive structure that sensitive beam 104 and mass block 102 form, the front of the sensitive structure of formation is such as
Shown in Fig. 2.Wherein preferably, penetrating the positive method of the silicon base 13 is deep reaction ion etching method.
Step 9: it as depicted in fig. 5e, makes the upper cover plate 11 and the upper cover plate 11 is bonded to the sensitive structure
Front, form the piezoresistance type acceleration sensor after 101 scribing of rectangle outer rim.So far, the present invention is formd
The piezoresistance type acceleration sensor.
In conclusion the present invention using wide and thin supporting beam and narrow and thick sensitive beam support mass block jointly, utilize
The big feature of narrow and thick sensitive beam the moment of inertia realizes that stress is concentrated, and is significantly reduced influence of the sensitive beam to the structure coefficient of stiffiness
To improve the figure of merit.Sensitive beam is produced near structure middle line and electric bridge connection type is combined to realize the suppression to paraxonic sensitivity
System.Sensitive beam flexure of the invention is smaller, can reduce paraxonic sensitivity；For supporting beam close to quality block edge, the arm of force is long, can
Preferably to inhibit mass block caused by paraxonic acceleration to reverse around middle line；Upper surface of support beam is lower than mass block and frame, and
Surface does not have oxide layer, can reduce structural deflection caused by oxidation ply stress.The thickness of supporting beam is thin, and it is stubborn to can reduce structure
Strong coefficient improves sensitivity and the figure of merit.So the present invention effectively overcomes various shortcoming in the prior art and has high industrial
Utility value.
The above-described embodiments merely illustrate the principles and effects of the present invention, and is not intended to limit the present invention.It is any ripe
The personage for knowing this technology all without departing from the spirit and scope of the present invention, carries out modifications and changes to above-described embodiment.Cause
This, institute is complete without departing from the spirit and technical ideas disclosed in the present invention by those of ordinary skill in the art such as
At all equivalent modifications or change, should be covered by the claims of the present invention.
Claims (10)
1. a kind of piezoresistance type acceleration sensor, which is characterized in that the piezoresistance type acceleration sensor includes at least:
Sensitive structure；It is bonded to the lower cover plate (12) at the positive upper cover plate of the sensitive structure (11) and its back side respectively；
The sensitive structure include: rectangle outer rim (101), in the rectangle outer rim center mass block
(102)；The mass block relative to the rectangle outer rim two groups of opposite side respectively symmetrically；The left and right sides of the mass block point
The supporting beam (103) fixed and be connected between the mass block and rectangle outer rim there are two not setting；
Be respectively provided between two supporting beams of every side at left and right sides of the mass block four be connected to the mass block with
And the sensitive beam (104) between the rectangle outer rim；The sensitive beam, mass block and the respective upper surface of rectangle outer rim
It is generally aligned in the same plane；The sensitive beam supporting beam more integrated distribution positioned at described mass block the same side is in the quality
Near the central axis of block in left-right direction；Four sensitive beams positioned at described mass block the same side, two-by-two for one group that
This is symmetrical about the central axis of the mass block；
The head or tail portion of each sensitive beam are respectively equipped with a force sensing resistance (105)；With the mass block it is described in
Position consistency of the force sensing resistance in respective sensitive beam in four nearest sensitive beams of mandrel linear distance；With the mass block
Position consistency of the force sensing resistance in respective sensitive beam in four farthest sensitive beams of the central axis distance；
The supporting beam and the respective lower surface of the sensitive beam are generally aligned in the same plane and the upper surface of the supporting beam is lower than institute
State the upper surface of sensitive beam；The width of the sensitive beam is much smaller than the width of the supporting beam；Each sensitive beam is equipped with
Connect the metal lead wire (106) at force sensing resistance both ends in the sensitive beam；The width of the sensitive beam is slightly wider than the force sensing resistance
With the width of metal lead wire.
2. piezoresistance type acceleration sensor according to claim 1, it is characterised in that: the center with the mass block
The force sensing resistance in four nearest sensitive beams of axial line distance is located at close to each sensitive beam of the mass block
Head position；The force sensing resistance position with the central axis distance of the mass block in four farthest sensitive beams
In the tail position of each sensitive beam far from the mass block.
3. piezoresistance type acceleration sensor according to claim 1, it is characterised in that: the center with the mass block
The force sensing resistance in four nearest sensitive beams of axial line distance is located remotely from the tail of each sensitive beam of the mass block
Portion position；The force sensing resistance with the central axis distance of the mass block in four farthest sensitive beams is located at
Close to the head position of each sensitive beam of the mass block.
4. piezoresistance type acceleration sensor according to claim 1, it is characterised in that: the upper surface of the sensitive beam is equipped with
Oxide layer；The upper surface non-oxidation layer of the supporting beam.
5. piezoresistance type acceleration sensor according to claim 1, it is characterised in that: the upper cover plate and lower cover plate are distinguished
It is bonded to the upper and lower surfaces of the rectangle outer rim；Gap below the mass block between the lower cover plate is equipped with
Positioned at the buffer stopper of the lower cover plate.
6. according to the production method of piezoresistance type acceleration sensor described in above-mentioned any one, which is characterized in that the production side
Method includes at least:
(1) silicon base (13) are provided, and makes the force sensing resistance in the front of the silicon base；
(2) corrosion barrier layer (131) are made respectively in the front and back of the silicon base；
(3) corrosion barrier layer of the silicon substrate bottom back side is etched until exposing the silicon substrate bottom back side, forms corrosion window
Mouthful；
(4) corrode the silicon substrate bottom back side until the remaining silicon fiml of corrosion area is with a thickness of the sensitivity along the corrosion window
Until the thickness of beam, the back side of the sensitive structure is formed, the part that is not corroded forms the mass block；
(5) metal lead wire at the force sensing resistance both ends is connected in the front production of the sensitive structure；
(6) it makes the lower cover plate and the lower cover plate is bonded to the back side of the sensitive structure；
(7) the positive metal lead wire two sides of the silicon base are thinned in etching, form concave regions, the concave regions silicon
With a thickness of the thickness of the supporting beam；
(8) the silicon base front is penetrated, the rectangle outer rim, supporting beam, sensitive beam and the matter by being separated from each other are formed
The front of the sensitive structure of gauge block composition；
(9) it makes the upper cover plate and the upper cover plate is bonded to the front of the sensitive structure, along the rectangle outer rim
The piezoresistance type acceleration sensor is formed after scribing.
7. the production method of piezoresistance type acceleration sensor according to claim 6, which is characterized in that the step (2)
In the corrosion barrier layer be silica, silicon nitride composite layer.
8. the production method of piezoresistance type acceleration sensor according to claim 6, which is characterized in that the step (4)
The corrosive liquid of the middle corrosion silicon substrate bottom back side is alkaline anisotropic corrosive liquid.
9. the production method of piezoresistance type acceleration sensor according to claim 8, which is characterized in that it is described alkalinity respectively to
Anisotropic etch liquid includes KOH, TMAH corrosive liquid.
10. the production method of piezoresistance type acceleration sensor according to claim 6, which is characterized in that the step (7)
It is deep reaction ion etching method that the method that the metal lead wire two sides form the concave regions, which is thinned, in middle etching；The step
(8) it is deep reaction ion etching method that the positive method of the silicon base is penetrated in.
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| CN107817364B (en) * | 2017-09-30 | 2019-10-11 | 西安交通大学 | A kind of two axis accelerometer chip of MEMS straight pull and vertical compression formula and preparation method thereof |
| CN107796955B (en) * | 2017-09-30 | 2019-10-11 | 西安交通大学 | Double-shaft acceleration sensor chip and preparation method thereof in more beam type single mass face |
| CN109254170B (en) * | 2018-11-30 | 2024-02-09 | 中国工程物理研究院电子工程研究所 | Integrated quartz double-vibration beam accelerometer and preparation method thereof |
| CN109596859B (en) * | 2019-01-18 | 2021-08-31 | 中国电子科技集团公司第十三研究所 | Piezoresistive acceleration sensor |
| CN111664975A (en) * | 2019-12-28 | 2020-09-15 | 黄辉 | Semiconductor nanowire mechanical sensor and preparation method thereof |
| CN112798821B (en) * | 2020-12-28 | 2021-10-08 | 武汉大学 | Double-shaft piezoelectric accelerometer |
| CN113008420A (en) * | 2021-03-01 | 2021-06-22 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor and method for manufacturing the same |
| CN117607489B (en) * | 2024-01-17 | 2024-04-09 | 中国工程物理研究院电子工程研究所 | Sensitive structure of piezoresistive acceleration sensor and acceleration sensor |
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| CN1111741C (en) * | 2000-08-25 | 2003-06-18 | 华北工学院微米纳米技术研究中心 | Integrated silicon microresistance type acceleration sensor and its manufacturing method |
| JP2007309654A (en) * | 2006-05-16 | 2007-11-29 | Sony Corp | Acceleration sensor and manufacturing method therefor |
| CN100468063C (en) * | 2007-04-19 | 2009-03-11 | 中北大学 | Three-axis piezoresistance micro-accelerometer |
| CN101118250B (en) * | 2007-09-13 | 2012-07-04 | 中国电子科技集团公司第十三研究所 | Silicon MEMS piezoresistance type acceleration sensor |
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| CN101430340A (en) * | 2008-12-06 | 2009-05-13 | 中北大学 | Silicon micro-piezoresistive accelerometer capable of reducing temperature excursion |
| TWI477780B (en) * | 2011-10-12 | 2015-03-21 | Richwave Technology Corp | Piezoresistive type z-axis accelerometer |
| CN102608356B (en) * | 2011-12-06 | 2018-09-21 | 中国计量学院 | A kind of double-shaft micromechanical resonant accelerometer structure and production method |
| CN204330809U (en) * | 2014-12-19 | 2015-05-13 | 中国科学院上海微系统与信息技术研究所 | A kind of piezoresistance type acceleration sensor |
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