CN109246565A - Silicon microphone and its manufacturing method - Google Patents
Silicon microphone and its manufacturing method Download PDFInfo
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- CN109246565A CN109246565A CN201810950172.3A CN201810950172A CN109246565A CN 109246565 A CN109246565 A CN 109246565A CN 201810950172 A CN201810950172 A CN 201810950172A CN 109246565 A CN109246565 A CN 109246565A
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- backboard
- silicon substrate
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- vibrating membrane
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R19/00—Electrostatic transducers
- H04R19/04—Microphones
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- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
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- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
Abstract
The method of silicon microphone structure provided by the invention and manufacture silicon microphone, the silicon microphone structure include a vibrating diaphragm body and a backboard body；The vibrating diaphragm body includes being located at the vibrating membrane of its first surface and extending to the cavity at the intermediate region of the vibrating membrane from the second surface of the vibrating diaphragm body, and the first surface of the vibrating diaphragm body is opposite with the second surface of the vibrating diaphragm body；The backboard body includes the supporting layer on the fringe region of backboard and the first surface positioned at the backboard, and the intermediate region of the backboard further includes having multiple acoustic aperture；The backboard body is bonded on the vibrating diaphragm body in such a way that the first surface of the backboard is towards the first surface of the vibrating diaphragm body, so that the intermediate region of the vibrating membrane and the intermediate region of the backboard are spaced apart by the supporting layer, to be formed with the air gap, the intermediate region of the intermediate region of the vibrating membrane and the backboard is corresponding.Present invention process is simple, product high sensitivity.
Description
Technical field
The present invention relates to MEMS (MEMS) technical fields based on silicon technology, more particularly, to a kind of silicon wheat
Gram wind and its manufacturing method.
Background technique
MEMS (MEMS) technology is a kind of new and high technology to be grown up based on conventional semiconductors technology, is used
Microelectronics Precision Manufacturing Technology makes it possible to manufacture small-sized electromechanical compo (from several microns to several hundred microns), with conventionally employed machinery
The respective devices of mode processing and fabricating are compared, and MEMS device has fairly obvious in volume, power consumption, weight even aspect of performance
Due to the manufacturing process using similar semiconductor circuit the batch micro operations of device may be implemented, and in parameter consistency in advantage
Aspect is with the obvious advantage, and MEMS device currently on the market has pressure sensor, accelerometer, gyroscope and silicon microphone etc..
The research of silicon microphone, which has been carried out, more than two decades, including has developed based on piezoelectric effect, piezoresistive effect and electricity
The structure of appearance formula, wherein capacitive-type silicon microphone is the structure of current most mainstream.One faced in capacitive-type silicon microphone production
A main problem is exactly the control of vibrating film stress.Membrane stress is the residual stress present in film after the film formation.It is existing
Film preparation means use deposit substantially, can have biggish residual stress by depositing obtained vibrating membrane, generally include heat
Mismatch stress and two kinds of intrinsic stress.Residual stress has larger impact to silicon microphone characteristic, its failure is even made when serious
It cannot work.Further more, big tensile residual stresses can also significantly reduce the mechanical sensitivity of vibrating membrane, and the machinery of vibrating membrane is sensitive
Degree again to the key index of microphone --- sensitivity is directly proportional, therefore big residual stress will cause indirectly microphone sensitive
The reduction of degree.Big residual compressive stress possibly even cause vibrating membrane occur buckling, thus keep microphone property unstable or
Failure.Such as the case where for film tensile stress, obtained film will be in tensile stress state, unless the membrane structure is set
It counts that strain can be generated and eliminates the stress.
Therefore, it reduces membrane stress and has become those skilled in the art's focus of attention to improve sensitivity of microphone, it is existing
There is the method by using the process conditions for improving preparation method deposit, or is such as annealed using some additional process to reduce vibration
The residual stress of dynamic film, but current this implementation method is used, technique is all more complicated.
Summary of the invention
The present invention proposes that a kind of silicon microphone and its manufacturing method improve the sensitive of silicon microphone to simplify manufacturing process
Degree.
According to the first aspect of the invention, a kind of manufacture silicon microphone method is proposed, comprising:
Form a vibrating diaphragm body and a backboard body；
The first surface of the vibrating diaphragm body is provided with vibrating membrane, is additionally provided in the vibrating diaphragm body from the vibrating diaphragm body
Second surface extends to the cavity at the intermediate region of the vibrating membrane, the first surface of the vibrating diaphragm body and the vibrating diaphragm body
Second surface is opposite；
The backboard body includes the supporting layer on the fringe region of backboard and the first surface positioned at the backboard, the back
The intermediate region of plate is provided with multiple acoustic aperture；
The backboard body is bonded in such a way that the first surface of the backboard is towards the first surface of the vibrating diaphragm body
On the vibrating diaphragm body, so that the intermediate region of the vibrating membrane and the intermediate region of the backboard pass through the supporting layer interval
It opens, to be formed with the air gap, the intermediate region of the intermediate region of the vibrating membrane and the backboard is corresponding.
Preferably, the mode of the bonding is Si-Si bonding.
Preferably, bulge-structure is formed on the intermediate region of the vibrating membrane first surface, the first of the vibrating membrane
Surface is the first surface of the vibrating diaphragm body.
Preferably, the method for forming the bulge-structure includes: that one layer first is formed on the vibrating diaphragm body first surface
Insulating layer；Etching first insulating layer of selectivity is described convex to be formed on the intermediate region of the vibrating membrane first surface
Play structure.
It preferably, further include that one is etched on the vibrating membrane for discharging the through-hole of air.
Preferably, opening of the cavity close to the vibrating diaphragm body second surface direction is less than close to the vibrating membrane direction
Opening.
Preferably, the method for forming the vibrating diaphragm body includes: to provide one the oneth SOI silicon substrate, the in the first SOI silicon substrate
Silicon substrate above one buried oxide layer is the vibrating membrane；Successively selectively corrode in the first SOI silicon substrate under the first buried oxide layer
The silicon substrate and first buried oxide layer of side are to form the cavity being located at below the intermediate region of the vibrating membrane, wherein
Silicon substrate thickness in the first SOI silicon substrate above the first buried oxide layer is less than the silicon substrate thickness below first buried oxide layer.
Preferably, first buried oxide layer is as the barrier layer for corroding the silicon substrate below first buried oxide layer.
Preferably, the method for forming the vibrating diaphragm body includes: to provide a monocrystalline silicon；To the monocrystalline silicon first surface into
To form one layer of doped layer, the doping junction depth of the doped layer is predetermined depth for row doping；From the second surface of the monocrystalline silicon
Intermediate region face start corrosion until the doped layer to form the cavity, wherein the doped layer be the vibrating diaphragm
The vibrating membrane in body.
Preferably, the dopant being doped to the first surface of the monocrystalline silicon is boron.
Preferably, the method for forming the backboard body includes: to provide one the 2nd SOI silicon substrate, in the 2nd SOI silicon substrate
The supporting layer is formed on the fringe region of first surface；Backboard is formed in the silicon substrate of the 2nd SOI silicon substrate first surface,
Wherein, the silicon substrate of the 2nd SOI silicon substrate first surface is the close side of the second buried oxide layer in the 2nd SOI silicon substrate
Silicon substrate.
Preferably, the method for forming the supporting layer includes: to form second on the first surface of the 2nd SOI silicon substrate
Insulating layer；The etching second insulating layer of selectivity is with the shape on the fringe region of the first surface of the 2nd SOI silicon substrate
At the supporting layer.
Preferably, the method for forming the backboard include: selective etching the 2nd SOI silicon substrate first surface wherein
The silicon substrate in one side edge region is to form the pattern of the backboard.
It preferably, further include the intermediate region of the selective etching backboard to form multiple acoustic aperture.
Preferably, further include the vibrating diaphragm body second surface formed one layer of third insulating layer.
Preferably, after the vibrating diaphragm body and the backboard body being bonded together, the 2nd SOI silicon substrate second is etched
The silicon substrate on surface is until second buried oxide layer；Etch second buried oxide layer and the third insulating layer, wherein the third
Insulating layer is for protecting the silicon substrate of the vibrating diaphragm body second surface to be etched.
It preferably, further include forming the first conductive gold on the fringe region of the vibrating membrane exposed by the backboard
Belong to.
Preferably, another the method also includes not being etched in the backboard when the backboard is set as conduction
The second conductive metal is formed in edge area.
Preferably, another the method also includes not being etched in the backboard when the backboard is set as non-conductive
The second conductive metal is formed on one side edge region and central area.
Preferably, the vibrating membrane is together with the supporting layer Direct Bonding.
According to the second aspect of the invention, a kind of silicon microphone is provided, comprising:
One vibrating diaphragm body and a backboard body；
The vibrating diaphragm body includes being located at the vibrating membrane of its first surface and extending to institute from the second surface of the vibrating diaphragm body
The cavity at the intermediate region of vibrating membrane is stated, the first surface of the vibrating diaphragm body is opposite with the second surface of the vibrating diaphragm body；
The backboard body includes the supporting layer on the fringe region of backboard and the first surface positioned at the backboard, the back
The intermediate region of plate further includes having multiple acoustic aperture；
The backboard body is bonded in institute in such a way that the first surface of the backboard is towards the first surface of the vibrating diaphragm body
It states on vibrating diaphragm body, so that the intermediate region of the vibrating membrane and the intermediate region of the backboard are spaced apart by the supporting layer,
To be formed with the air gap, the intermediate region of the intermediate region of the vibrating membrane and the backboard is corresponding.
Preferably, the mode of the bonding is Si-Si bonding.
It preferably, further include the bulge-structure on the intermediate region of the vibrating membrane first surface.
Preferably, the vibrating membrane further includes one for discharging the through-hole of air.
Preferably, opening of the cavity close to the vibrating diaphragm body second surface direction is less than close to the vibrating membrane direction
Opening.
Preferably, the vibrating membrane is the silicon substrate in SOI silicon substrate above the first buried oxide layer, wherein the first SOI silicon substrate
In silicon substrate thickness above the first buried oxide layer be less than the silicon substrate thickness below first buried oxide layer.
Preferably, the vibrating membrane is the monocrystalline silicon layer of high-concentration dopant boron.
Preferably, the wherein one side edge of the backboard exposes the fringe region of the vibrating membrane.
It preferably, further include being located at by the first conductive metal on the exposed vibrating membrane fringe region of the backboard.
It preferably, further include the second conductive metal in another side edge of the backboard.
Preferably, when the backboard is set as non-conductive, the silicon microphone further includes being located at the backboard middle area
Second conductive metal in domain.
The method of silicon microphone structure provided by the invention and manufacture silicon microphone, the backboard and vibrating diaphragm body all use
SOI silica-base material and integrated artistic design, so that photoetching process of the invention greatly simplifies compared with the existing technology, in addition,
The vibrating membrane is bonded together by way of being bonded with the backboard, so that being formed between the vibrating membrane and the backboard
The air gap technique it is simpler.
Detailed description of the invention
By referring to the drawings to the description of the embodiment of the present invention, above-mentioned and other purposes of the invention, feature and
Advantage will be apparent from, in the accompanying drawings:
Fig. 1 is the structural schematic diagram according to the silicon microphone of the embodiment of the present invention；
Fig. 2 a-2k is the schematic sectional view for manufacturing each step of the method for silicon microphone of the embodiment of the present invention.
Specific embodiment
Hereinafter reference will be made to the drawings, and the present invention will be described in more detail.In various figures, identical element is using similar attached
Icon is remembered to indicate.For the sake of clarity, the various pieces in attached drawing are not necessarily to scale.Furthermore, it is possible to be not shown certain
Well known part.For brevity, the semiconductor structure obtained after several steps can be described in a width figure.
It should be appreciated that being known as being located at another floor, another area when by a floor, a region in the structure of outlines device
When domain " above " or " top ", can refer to above another layer, another region, or its with another layer, it is another
Also comprising other layers or region between a region.Also, if device overturn, this layer, a region will be located at it is another
Layer, another region " following " or " lower section ".
If, herein will be using " A is directly on B in order to describe located immediately at another layer, another region above scenario
The form of presentation of face " or " A on B and therewith abut ".In this application, " A is in B " indicates that A is located in B, and
And A and B is abutted directly against, rather than A is located in the doped region formed in B.
In this application, term " semiconductor structure " refers to entire half formed in each step of manufacturing semiconductor devices
The general designation of conductor structure, including all layers formed or region.
Many specific details of the invention, such as structure, material, size, the processing work of device is described hereinafter
Skill and technology, to be more clearly understood that the present invention.But it just as the skilled person will understand, can not press
The present invention is realized according to these specific details.
Silicon microphone provided by the invention includes a vibrating diaphragm body and a backboard body；The vibrating diaphragm body includes being located at first surface
Vibrating membrane and extend to the cavity from the intermediate region of the vibrating membrane, the vibrating diaphragm body from the second surface of the vibrating diaphragm body
First surface it is opposite with the second surface of the vibrating diaphragm body；The backboard body includes backboard and the first table positioned at the backboard
Supporting layer on the fringe region in face, the intermediate region of the backboard further include having multiple acoustic aperture；The backboard body is with the back
The mode of the first surface of plate towards the first surface of the vibrating diaphragm body is bonded on the vibrating diaphragm body, so that the vibrating membrane
Intermediate region and the intermediate region of the backboard are spaced apart by the supporting layer, to be formed with the air gap, the vibrating membrane
Intermediate region and the backboard intermediate region it is corresponding.
It is as shown in Figure 1 the silicon microphone structural schematic diagram of the embodiment of the present invention, in the present embodiment, the silicon microphone
Including vibrating diaphragm body 115 and backboard body, the backboard body includes the fringe region of backboard 109 and the first surface positioned at the backboard
Upper supporting layer 107, the intermediate region of the backboard are provided with multiple acoustic aperture 108；The vibrating diaphragm body 115 include setting its first
The vibrating membrane 112 on surface and the cavity 110 from the intermediate region of the vibrating membrane is extended to from the second surface of the vibrating diaphragm body,
The first surface of the vibrating diaphragm body is opposite with the second surface of the vibrating diaphragm body；The backboard body is with the first of the backboard 109
The mode of surface towards the first surface of the vibrating diaphragm body 115 is bonded on the vibrating diaphragm body 115, so that the vibrating membrane 112
Intermediate region and the backboard 109 intermediate region by the supporting layer 107 be spaced apart, to be formed with the air gap 118,
The intermediate region of the vibrating membrane 112 and the intermediate region of the backboard 109 are corresponding.
Specifically, the supporting layer 107 of 109 first surface of backboard and the vibrating membrane 112 are straight by way of being bonded
Contact, for example, can be connected by way of Si-Si bonding；The method of the Si-Si bonding are as follows: first by the supporting layer 107
The face contacted with the vibrating membrane 112 carries out cleaning and activation appropriate；The two, which is fit together, at room temperature makes its dependence
The intermolecular force of short distance is pulled together；By the vibrating diaphragm body 115 of fitting and backboard body in O2Or N2Pass through a few hours under environment
The high temperature anneal, make interface occur physical-chemical reaction, increase bond strength to form overall structure.
In the present embodiment, the silicon microphone further includes the protrusion positioned at the intermediate region of the vibrating membrane first surface
Structure 103, to prevent vibrating membrane 112 from adhered on the backboard 109 during the motion, the height of the bulge-structure 103
Less than the height of the supporting layer 107；Wherein, the first surface of the vibrating membrane 112 is the first table of the vibrating diaphragm body 115
Face；The vibrating membrane 112 further includes the through-hole 104 positioned at 112 intermediate region of vibrating membrane, for discharging the air gap
Air pressure, reduce its stress generated to the vibrating membrane, increase the sensitivity of the vibrating membrane, it is further, described logical
The edge that hole 104 is located at 112 intermediate region of vibrating membrane is optimal location；As shown in Figure 1, the pattern of the backboard 109
Edge for wherein side is etched, and with the edge of the exposed vibrating membrane 112, the silicon microphone further includes being located at by institute
It states the first conductive metal 117 of exposed 112 edge of the vibrating membrane of backboard 109 and is located at 109 other side of backboard
The second conductive metal 111 on edge.
In the present embodiment, the vibrating diaphragm body 115 includes SOI silicon substrate, and the SOI silicon substrate includes vibrating membrane 112, first buries
Oxygen layer 113 and underlay substrate 114；The vibrating membrane 112 is the silicon substrate in SOI silicon substrate above the first buried oxide layer, wherein described
Silicon substrate thickness in SOI silicon substrate above the first buried oxide layer is less than the silicon substrate thickness below first buried oxide layer；Described first
Buried oxide layer 113 and the underlay substrate 114 include a cavity 110, and the cavity 110 is located at the intermediate region of the vibrating membrane
Lower section extends to from the intermediate region of the vibrating membrane from the second surface of the underlay substrate 114, by etching the substrate base
Plate 114 and the formation of the first buried oxide layer 113, enter for sound wave and provide channel, and first buried oxide layer 113 is as the etching substrate
The barrier layer of substrate 114.The shape of the cavity 110 is up big and down small, that is to say, that the cavity 110 is close to the vibrating membrane
Direction opening be greater than the second surface close to the vibrating diaphragm body direction opening, being designed in this way can be improved silicon microphone and exists
The sensitivity response of high band.
Because monocrystalline silicon thin film has the characteristics that residual stress is small, mechanical oscillation performance is extremely excellent, in the present embodiment, described
Backboard body and the vibrating diaphragm body all use single crystal silicon material to reduce stress, improve the sensitivity of silicon microphone.
In the present embodiment, the backboard and the vibrating membrane are all configured to have electric conductivity, for example, can pass through doping
Impurity makes it have electric conductivity, can include being located at the vibrating membrane 112 directly as two pole plates of capacitor, the metal electrode
Far from the first electrode 117 by the first electrode 117 of the exposed fringe region of the backboard 109 and on the backboard
The second electrode 111 in other edge region.Certainly, if those skilled in the art are in order to reduce parasitic capacitance, by the backboard 109
It is designed as non-conductive, then second electrode can be also set on the central area of backboard 109, using metal conducting layer as capacity plate antenna
One pole plate.
In addition, in the present embodiment, the vibrating membrane and the backboard are designed to square, certainly, art technology
Personnel can also be set to other shapes according to demand, for example, circle, octagon etc..
The working principle of the silicon microphone proposed by the invention are as follows: sound wave is transmitted to vibrating membrane by cavity 110
112, cause vibrating membrane 112 to move to backboard 109, then the distance between vibrating membrane 112 and backboard 109 will become smaller, the two shape
At capacity plate antenna value just will increase, detect the variation of the capacitance by circuit, realize that acoustic signals turn to electric signal
It changes.
In another embodiment, the single crystal silicon material of high-concentration dopant boron namely described can also be used in the vibrating diaphragm body 115
Vibrating membrane is the monocrystalline silicon of highly doped boron, adulterates boron in the upper surface of the monocrystalline silicon, then passes through wet etching monocrystalline silicon
The back side forms cavity, because corrosive liquid is very slow for the corrosion of highly doped boron, it is possible to play the role of self-corrosion stopping.Cause
It is conductive for the monocrystalline silicon of doping, then can come directly as the pole plate of capacitor using.
If Fig. 2 a-2k show the sectional view in each stage of the silicon microphone of the manufacture embodiment of the present invention, described in manufacture
The method of silicon microphone includes:
Form a vibrating diaphragm body and a backboard body；
The first surface of the vibrating diaphragm body is provided with vibrating membrane, is additionally provided in the vibrating diaphragm body from the vibrating diaphragm body
Second surface extends to the cavity at the intermediate region of the vibrating membrane, the first surface of the vibrating diaphragm body and the vibrating diaphragm body
Second surface is opposite；
The backboard body includes the supporting layer on the fringe region of backboard and the first surface positioned at the backboard, the back
The intermediate region of plate is provided with multiple acoustic aperture；
The backboard body is bonded in such a way that the first surface of the backboard is towards the first surface of the vibrating diaphragm body
On the vibrating diaphragm body, so that the intermediate region of the vibrating membrane and the intermediate region of the backboard pass through the supporting layer interval
It opens, to be formed with the air gap, the intermediate region of the intermediate region of the vibrating membrane and the backboard is corresponding.
First by taking vibrating diaphragm body and back plate body material are SOI silicon substrate as an example, the step of manufacturing the silicon microphone is specifically described:
Such as Fig. 2 a, a SOI silicon substrate 101 is provided, forms first in the first surface and second surface of the SOI silicon substrate 101
Insulating layer 102, in the present embodiment, first insulating layer 102 are oxide layer, are formed by oxidation technology.Wherein, described
SOI silicon substrate is monocrystalline silicon, and the first surface of the SOI silicon substrate 101 is the first buried oxide layer 113 in the SOI silicon substrate 101
The second surface on close surface, the SOI silicon substrate 101 is opposite with the first surface.
Such as Fig. 2 b, bulge-structure 103 is formed in the first surface of the SOI silicon substrate 101, described in the etching by selectivity
First insulating layer 102 of 101 first surface of SOI silicon substrate forms multiple bulge-structures 103, and first in the SOI silicon substrate 101 buries
Silicon substrate above oxygen layer 113 is vibrating membrane 112, and the bulge-structure 103 is to prevent from adhering in the vibrating membrane motion process
On backboard formed in subsequent technique, the bulge-structure is located at the intermediate region of the first surface of the vibrating membrane.Wherein,
The first surface of the vibrating membrane is the first surface of the SOI silicon substrate, the silicon substrate thickness above first buried oxide layer 113
Less than the silicon substrate thickness below first buried oxide layer 113.In the present embodiment, the bulge-structure 103 is selected as 3, when
So, those skilled in the art can also tie according to the protrusion of the specific design requirement of silicon microphone or performance requirement selection any number
Structure.
Such as Fig. 2 c, in the silicon substrate above the first buried oxide layer 113 in the SOI silicon substrate 101 etch a through-hole 104 with
The pattern of the vibrating membrane 112 is formed, the through-hole 104 stops at described since the first surface of the SOI silicon substrate 101
In first buried oxide layer 113, the through-hole 104 is for discharging air between backboard formed in the vibrating membrane and subsequent technique
Air pressure in gap increases the sensitive of the vibrating membrane to eliminate the effect that the air of compression generates power to the vibrating membrane 112
Degree.
Fig. 2 d provides a SOI silicon substrate 105, and second insulating layer 106 is formed on the first surface of the SOI silicon substrate 105,
In the present embodiment, the second insulating layer 106 is oxide layer, is formed by oxidation technology.In the present embodiment, the oxidation
Layer with a thickness of 3 μm.Wherein, the first surface of the SOI silicon substrate 105 is the second buried oxide layer in the SOI silicon substrate 105
The second surface on 120 close surfaces, the SOI silicon substrate 105 is opposite with the first surface.
Fig. 2 e, photoetching simultaneously etch the second insulating layer 106 to form supporting layer 107, between being used in the subsequent process
Every the vibrating membrane 112 and backboard, to form a air gap, in the present embodiment, the branch between vibrating membrane and backboard
The number for supportting layer is 2, and certainly, those skilled in the art can also be arbitrarily arranged as needed；In addition, in the present embodiment,
The supporting layer is insulation support layer, and those skilled in the art also may be selected the material that other can have phase same-action and be used as branch
Support layer.
Fig. 2 f etches the fringe region of the wherein side of the silicon substrate in the SOI silicon substrate 105 above second buried oxide layer 120
To expose the fringe region of second buried oxide layer 120, the pattern of backboard 109 is formed, and is existed simultaneously by the technique of etching
The intermediate region of backboard 109 forms multiple acoustic aperture 108.Wherein, the middle area of the intermediate region of the backboard and the vibrating membrane
Domain is corresponding.In the present embodiment, the number of the acoustic aperture 108 is 4, and certainly, those skilled in the art can also be according to need
Want the number of any selection acoustic aperture.
Fig. 2 g, by the vibrating membrane 112 of 101 first surface of SOI silicon substrate and the SOI silicon substrate by way of bonding
Supporting layer 107 on 105 first surfaces is bonded together, so that the SOI silicon substrate 101 is located under the SOI silicon substrate 105
Side, the intermediate region of the vibrating membrane 112 and the intermediate region of the backboard 109 are spaced apart by the supporting layer 109, with shape
At with the air gap.
In the present embodiment, the mode of Si-Si bonding is selected to be bonded, certainly, those skilled in the art can also be used
Other bonding patterns are bonded.The method of the specific Si-Si bonding are as follows: first by the supporting layer 107 and the vibrating membrane
The face of 112 contacts carries out cleaning and activation appropriate；The two, which is fit together, at room temperature makes it by the intermolecular of short distance
Active force is pulled together；By the vibrating diaphragm body 115 of fitting and backboard body in O2Or N2Pass through at the high annealing of a few hours under environment
Reason makes interface that physical-chemical reaction occur, and increases bond strength to form overall structure.
In addition, in the present embodiment, after the SOI silicon substrate 101 is located at the SOI silicon substrate 105 bonding, the multiple protrusion
Structure is located at the centre of two supporting layers, certainly, the positional relationship of bulge-structure described herein and the insulation support layer
It is not particularly limited, those skilled in the art can also design self-setting according to silicon microphone structure.
Fig. 2 h, selectively etching is straight upwards since the first insulating layer 102 of the second surface of the SOI silicon substrate 101
To stopping at first buried oxide layer 113, then it is further continued for etching first buried oxide layer 113 until exposing the vibration
Film 112 forms bottom cavity 110, enters for sound wave and provides channel, the cavity is located under the vibrating membrane intermediate region
Side.The shape of the cavity be it is up big and down small, that is, the cavity 110 close to the vibrating membrane direction opening be greater than it is close
The opening in the 101 second surface direction of SOI silicon substrate.Wherein, first buried oxide layer 113 is as the resistance for etching silicon substrate below
Barrier.
Fig. 2 i is removed the silicon substrate of the second surface of the SOI silicon substrate 105 by front wet etching, stops at the SOI
Second buried oxide layer 120 of silicon substrate 105, for protecting in the SOI silicon substrate 101 the in described this step process of first insulating layer 102
Silicon substrate below two buried oxide layers 113 is etched.
Fig. 2 j removes the second buried oxide layer 120 and the SOI silicon substrate 101 in the SOI silicon substrate 105 by wet etching
Lower surface the first insulating layer 102.
Fig. 2 k is respectively formed conductive metal on the backboard 109 and the vibrating membrane 112.Specifically, by the back
The first conductive metal 117 is formed on the fringe region of the exposed vibrating membrane 112 in the one side edge region of plate 109, described
The second conductive metal 111, first conductive metal 117 and second conductive gold are formed in another edge area of backboard
Belong to 111 not in same plane, and is located at two opposite fringe regions.In addition, usually the backboard and the vibrating membrane all can
It is designed with electric conductivity, if but in order to reduce parasitic capacitance, the backboard can be designed as non-conductive, then the second conductive gold
Belonging to 111 further includes the conductive metal on the backboard intermediate region, using the conductive metal as capacitor pole plate.
In another embodiment, the backboard body can not also use SOI silicon substrate, but use monocrystalline silicon, specific formation side
Method is as follows: providing a monocrystalline silicon；It is doped to the first surface of the monocrystalline silicon to form one layer of doped layer, the doped layer
Doping junction depth be predetermined depth, the doped layer be high-concentration dopant；From the intermediate region of the second surface of the monocrystalline silicon
Face starts corrosion until stopping at the doped layer to form the cavity, wherein the doped layer is in the vibrating diaphragm body
The vibrating membrane.Dopant in the doping process is boron, and the corrosive liquid is KOH or TMAH (tetramethylammonium hydroxide)
Deng, during forming cavity because corrosive liquid corrode in the silicon substrate of high-concentration dopant boron it is very slow, can play from
The effect of etching-stop.
Because monocrystalline silicon thin film has the characteristics that residual stress is small, mechanical oscillation performance is extremely excellent, in the present embodiment, described
Backboard and the vibrating diaphragm body all use single crystal silicon material to reduce stress, improve the sensitivity of silicon microphone.
The method of silicon microphone structure provided by the invention and manufacture silicon microphone, the backboard and vibrating diaphragm body all use
SOI silica-base material and integrated artistic design, so that photoetching process of the invention greatly simplifies compared with the existing technology, in addition,
The vibrating membrane is bonded together by way of being bonded with the backboard, so that being formed between the vibrating membrane and the backboard
The air gap technique it is simpler.
It is as described above according to the embodiment of the present invention, these embodiments details all there is no detailed descriptionthe, also not
Limiting the invention is only the specific embodiment.Obviously, as described above, can make many modifications and variations.This explanation
These embodiments are chosen and specifically described to book, is principle and practical application in order to better explain the present invention, thus belonging to making
Technical field technical staff can be used using modification of the invention and on the basis of the present invention well.The present invention is only by right
The limitation of claim and its full scope and equivalent.
Claims (31)
1. a kind of manufacture silicon microphone method characterized by comprising
Form a vibrating diaphragm body and a backboard body；
The first surface of the vibrating diaphragm body is provided with vibrating membrane, and second from the vibrating diaphragm body is additionally provided in the vibrating diaphragm body
Surface extends to the cavity at the intermediate region of the vibrating membrane, the first surface of the vibrating diaphragm body and the second of the vibrating diaphragm body
Surface is opposite；
The backboard body includes the supporting layer on the fringe region of backboard and the first surface positioned at the backboard, the backboard
Intermediate region is provided with multiple acoustic aperture；
The backboard body is bonded in such a way that the first surface of the backboard is towards the first surface of the vibrating diaphragm body described
On vibrating diaphragm body, so that the intermediate region of the vibrating membrane and the intermediate region of the backboard are spaced apart by the supporting layer, with
It is formed with the air gap, the intermediate region of the intermediate region of the vibrating membrane and the backboard is corresponding.
2. the method according to claim 1, wherein the mode of the bonding is Si-Si bonding.
3. the method according to claim 1, wherein further including in the intermediate region of the vibrating membrane first surface
Upper formation bulge-structure, the first surface of the vibrating membrane are the first surface of the vibrating diaphragm body.
4. according to the method described in claim 3, it is characterized in that, the method for forming the bulge-structure includes:
One layer of first insulating layer is formed on the vibrating diaphragm body first surface；
Etching first insulating layer of selectivity is to form the protrusion on the intermediate region of the vibrating membrane first surface
Structure.
5. according to the method described in claim 4, it is characterized in that, further including etching one on the vibrating membrane for discharging
The through-hole of air.
6. according to the method described in claim 5, it is characterized in that, the cavity is close to the vibrating diaphragm body second surface direction
Opening is less than the opening close to the vibrating membrane direction.
7. according to the method described in claim 6, it is characterized in that, the method for forming the vibrating diaphragm body includes:
One the oneth SOI silicon substrate is provided, the silicon substrate in the first SOI silicon substrate above the first buried oxide layer is the vibrating membrane；
Successively selectively corrode silicon substrate in the first SOI silicon substrate below the first buried oxide layer and first buried oxide layer with
The cavity being located at below the intermediate region of the vibrating membrane is formed,
Wherein, the silicon substrate thickness in the first SOI silicon substrate above the first buried oxide layer is less than the silicon below first buried oxide layer
Base thickness.
8. the method according to the description of claim 7 is characterized in that first buried oxide layer is as corrosion first buried oxide layer
The barrier layer of the silicon substrate of lower section.
9. according to the method described in claim 6, it is characterized in that, the method for forming the vibrating diaphragm body includes:
One monocrystalline silicon is provided；
It is doped to the first surface of the monocrystalline silicon to form one layer of doped layer, the doping junction depth of the doped layer is predetermined
Depth；
Corrode from the doped layer since the intermediate region face of the second surface of the monocrystalline silicon to form the cavity,
Wherein, the doped layer is the vibrating membrane in the vibrating diaphragm body.
10. the method according to claim 1, wherein being mixed to what the first surface of the monocrystalline silicon was doped
Miscellaneous dose is boron.
11. the method according to claim 1, wherein the method for forming the backboard body includes:
One the 2nd SOI silicon substrate is provided,
The supporting layer is formed on the fringe region of the first surface of the 2nd SOI silicon substrate；
Backboard is formed in the silicon substrate of the 2nd SOI silicon substrate first surface, wherein the 2nd SOI silicon substrate first surface
Silicon substrate is the silicon substrate of the close side of the second buried oxide layer in the 2nd SOI silicon substrate.
12. according to the method for claim 11, which is characterized in that the method for forming the supporting layer includes:
Second insulating layer is formed on the first surface of the 2nd SOI silicon substrate；
The etching second insulating layer of selectivity is to form institute on the fringe region of the first surface of the 2nd SOI silicon substrate
State supporting layer.
13. according to the method for claim 12, which is characterized in that the method for forming the backboard includes: selective quarter
The silicon substrate in the 2nd SOI silicon substrate first surface wherein one side edge region is lost to form the pattern of the backboard.
14. according to the method for claim 13, which is characterized in that further include the middle area of the selective etching backboard
Domain is to form multiple acoustic aperture.
15. according to the method for claim 13, which is characterized in that further include the second surface formation one in the vibrating diaphragm body
Layer third insulating layer.
16. according to the method for claim 15, which is characterized in that the vibrating diaphragm body and the backboard body are bonded together
Later,
The silicon substrate of the 2nd SOI silicon substrate second surface is etched until second buried oxide layer；
Second buried oxide layer and the third insulating layer are etched,
Wherein, the third insulating layer is for protecting the silicon substrate of the vibrating diaphragm body second surface to be etched.
17. according to the method for claim 13, which is characterized in that further include in the vibrating membrane exposed by the backboard
Fringe region on form the first conductive metal.
18. according to the method for claim 17, which is characterized in that when the backboard is set as conduction, the method is also
Including forming the second conductive metal in another edge area that the backboard is not etched.
19. according to the method for claim 17, which is characterized in that when the backboard is set as non-conductive, the method
It further include forming the second conductive metal in another edge area and central area that the backboard is not etched.
20. the method according to claim 1, wherein the vibrating membrane and the supporting layer Direct Bonding are one
It rises.
21. a kind of silicon microphone characterized by comprising
One vibrating diaphragm body and a backboard body；
The vibrating diaphragm body includes being located at the vibrating membrane of its first surface and extending to the vibration from the second surface of the vibrating diaphragm body
Cavity at the intermediate region of dynamic film, the first surface of the vibrating diaphragm body are opposite with the second surface of the vibrating diaphragm body；
The backboard body includes the supporting layer on the fringe region of backboard and the first surface positioned at the backboard, the backboard
Intermediate region further includes having multiple acoustic aperture；
The backboard body is bonded in the vibration in such a way that the first surface of the backboard is towards the first surface of the vibrating diaphragm body
On membrane body, so that the intermediate region of the vibrating membrane and the intermediate region of the backboard are spaced apart by the supporting layer, with shape
At with the air gap, the intermediate region of the intermediate region of the vibrating membrane and the backboard is corresponding.
22. silicon microphone according to claim 21, which is characterized in that the mode of the bonding is Si-Si bonding.
23. silicon microphone according to claim 21, which is characterized in that further include being located at the vibrating membrane first surface
Bulge-structure on intermediate region.
24. silicon microphone according to claim 23, which is characterized in that the vibrating membrane further includes one for discharging sky
The through-hole of gas.
25. silicon microphone according to claim 24, which is characterized in that the cavity is close to the vibrating diaphragm body second surface
The opening in direction is less than the opening close to the vibrating membrane direction.
26. silicon microphone according to claim 25, which is characterized in that the vibrating membrane buries oxygen in SOI silicon substrate first
The silicon substrate of layer top, wherein the silicon substrate thickness in the first SOI silicon substrate above the first buried oxide layer is less than first buried oxide layer
The silicon substrate thickness of lower section.
27. silicon microphone according to claim 25, which is characterized in that the vibrating membrane is the monocrystalline of high-concentration dopant boron
Silicon layer.
28. silicon microphone according to claim 21, which is characterized in that the wherein one side edge of the backboard exposes institute
State the fringe region of vibrating membrane.
29. silicon microphone according to claim 28, which is characterized in that further include be located at by the backboard it is exposed described in
The first conductive metal on vibrating membrane fringe region.
30. silicon microphone according to claim 29, which is characterized in that further include being located in another side edge of the backboard
The second conductive metal.
31. silicon microphone according to claim 30, which is characterized in that described when the backboard is set as non-conductive
Silicon microphone further includes the second conductive metal positioned at the backboard intermediate region.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810950172.3A CN109246565A (en) | 2018-08-20 | 2018-08-20 | Silicon microphone and its manufacturing method |
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| CN201810950172.3A CN109246565A (en) | 2018-08-20 | 2018-08-20 | Silicon microphone and its manufacturing method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111983825A (en) * | 2020-08-28 | 2020-11-24 | 济南晶正电子科技有限公司 | Electro-optic crystal film and preparation method thereof |
| CN115278487A (en) * | 2022-07-28 | 2022-11-01 | 维沃移动通信有限公司 | Microphone, preparation method thereof and electronic equipment |
| CN115474144A (en) * | 2021-06-11 | 2022-12-13 | 美商富迪科技股份有限公司 | Micro-electro-mechanical system microphone |
| CN117641215A (en) * | 2024-01-25 | 2024-03-01 | 镭友芯科技(苏州)有限公司 | Microphone sensor and preparation method thereof |
-
2018
- 2018-08-20 CN CN201810950172.3A patent/CN109246565A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111983825A (en) * | 2020-08-28 | 2020-11-24 | 济南晶正电子科技有限公司 | Electro-optic crystal film and preparation method thereof |
| CN115474144A (en) * | 2021-06-11 | 2022-12-13 | 美商富迪科技股份有限公司 | Micro-electro-mechanical system microphone |
| CN115278487A (en) * | 2022-07-28 | 2022-11-01 | 维沃移动通信有限公司 | Microphone, preparation method thereof and electronic equipment |
| CN117641215A (en) * | 2024-01-25 | 2024-03-01 | 镭友芯科技(苏州)有限公司 | Microphone sensor and preparation method thereof |
| CN117641215B (en) * | 2024-01-25 | 2024-04-16 | 镭友芯科技(苏州)有限公司 | Microphone sensor and preparation method thereof |
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Application publication date: 20190118 |