CN104616971B - Pressure sensor and forming method thereof - Google Patents
Pressure sensor and forming method thereof Download PDFInfo
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- CN104616971B CN104616971B CN201310543025.1A CN201310543025A CN104616971B CN 104616971 B CN104616971 B CN 104616971B CN 201310543025 A CN201310543025 A CN 201310543025A CN 104616971 B CN104616971 B CN 104616971B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00349—Creating layers of material on a substrate
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/12—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor
Abstract
The forming method of a kind of pressure sensor and forming method thereof, wherein pressure sensor includes：Substrate is provided, formed with transistor in substrate；Interlayer dielectric layer, interlayer dielectric layer covering substrate and transistor are formed, is exposed in interlayer dielectric layer formed with bottom crown, the upper surface of bottom crown；SiGe layer is formed on interlayer dielectric layer, cavity is formed between SiGe layer and bottom crown；Etching stop layer is formed on the sige layer, and the first SiN layer is formed on etching stop layer；The first SiN layer is etched to form press section and surround the edge part of press section, expose to etching stop layer upper surface, press section is spaced from each other with edge part, and press section corresponds to empty cavity position, includes the first fluoro-gas in the etching gas that the process for etching the first SiN layer uses；Etching stop layer is etched, is exposed to SiGe layer.The pressure sensor formed using the technical program, reliability are improved, and performance is preferable.
Description
Technical field
The present invention relates to technical field of semiconductors, more particularly to pressure sensor and forming method thereof.
Background technology
Existing pressure sensor for micro electro-mechanical system, it is to pass through pressure sensor switch in semiconductor applications（Pressure
Sensor Shutter）Extraneous gas pressure is received, gas pressure is then converted into electric signal, measures specific pressure
Information.
In the prior art, forming the method for pressure sensor switch includes：
Reference picture 1, there is provided substrate 1, on the base 1 with transistor；On the base 1 formed with interlayer dielectric layer 2, interlayer
Dielectric layer 2 covers the transistor and substrate 1；Formed with interconnection line 4 and bottom crown 32, the He of interconnection line 4 in interlayer dielectric layer 2
Bottom crown 32 is spaced from each other, and is electrically connected respectively with transistor, and upper surface, the upper surface of bottom crown 32 of the interconnection line 4 are sudden and violent
Dew.
Reference picture 2, on bottom crown 32 formed amorphous carbon layer 6, the amorphous carbon layer 6 define cavity height and
Position；SiGe layer 31 is formed on interlayer dielectric layer 2, the SiGe layer 31 covers the amorphous carbon layer 6, interconnection line 4 and layer
Between dielectric layer 2.
Reference picture 3, remove amorphous carbon layer 6（Reference picture 2）, form cavity 7 in the opening position of amorphous carbon layer, then it is empty
The bottom crown 32 of chamber 7, the SiGe layer of the top of cavity 7 and the lower section of cavity 7 constitutes a capacitor；Then, in SiGe layer 31
Form SiN layer 50.
Reference picture 4, photoetching, etching SiN layer 50（Reference picture 3）, form the press section 52 and press section for corresponding to the position of cavity 7
Edge part 51 around 52, press section 52 are used as pressure sensor switch.
When ambient pressure is applied on press section 52, bottom crown 32 and the SiGe layer part relative with bottom crown 32 are changed
Between spacing, and then change the capacitance for the capacitor being made up of bottom crown 32 and SiGe layer 31.By transistor AND gate institute
State SiGe layer 31 and bottom crown 32 electrically connects, the capacitance signal is transferred to transistor, includes the control circuit conversion of transistor
Into pressure value.
But the pressure sensor reliability including pressure sensor switch that prior art is formed is not high, performance is bad.
The content of the invention
The present invention solves the problems, such as there is the pressure sensor reliability of the pressure sensor switch of prior art formation
Not high, performance is bad.
To solve the above problems, the present invention provides a kind of forming method of pressure sensor, the formation of the pressure sensor
Method includes：
Substrate is provided, on the substrate formed with transistor；
Interlayer dielectric layer is formed, the interlayer dielectric layer covers the substrate and transistor, in the interlayer dielectric layer
Formed with bottom crown, the upper surface exposure of the bottom crown；
SiGe layer is formed on the interlayer dielectric layer, cavity is formed between the SiGe layer and bottom crown；
Etching stop layer is formed in the SiGe layer, the first SiN layer is formed on the etching stop layer；
Etch first SiN layer to form press section and surround the edge part of press section, to the etching stop layer upper table
Show out, the press section is spaced from each other with edge part, and the press section corresponds to the empty cavity position, in etching described first
The etching gas that the process of SiN layer uses include the first fluoro-gas；
The etching stop layer is etched, is exposed to SiGe layer.
Alternatively, the etching stop layer is the first metal layer.
Alternatively, the material of the first metal layer is Ti, TiN, TaN or Ta.
Alternatively, before the etching stop layer is formed, the second SiN layer is formed in the SiGe layer, described the
Cushion is formed in two SiN layers；
After the first SiN layer is etched, the second SiN layer of the etching stop layer, cushion and segment thickness is etched, is buffered
The material of layer makes the etch rate of the etching etching stop layer identical with the etch rate for etching the cushion, etching buffering
The etch rate of layer is more than the etch rate of the second SiN layer of etching；
Remaining second SiN layer is etched, is exposed to SiGe layer, etches the etching used during remaining second SiN layer
Gas includes the second fluoro-gas, and the fluorinated volume of second fluoro-gas is less than the fluorinated volume of the first fluoro-gas.
Alternatively, before the cushion is formed, second metal layer is formed in second SiN layer；Or
Before the cushion is formed, second metal layer is formed in second SiN layer, in the second metal layer
The 3rd SiN layer of upper formation.
Alternatively, the material of the cushion is SiGe, polysilicon or photoresist.
Alternatively, the second SiN layer process of the etching stop layer, cushion and segment thickness, the etching used are etched
Gas is Cl2、HBr、O2Mixed gas.
Alternatively, the second SiN layer process of the etching stop layer, cushion and segment thickness, radio-frequency power model are etched
It is 9.5~10.5mTorr to enclose for 450~550W, pressure range, and bias power ranges are 54~66W, Cl2Range of flow be
105~132sccm, O2Range of flow be 3~5sccm, HBr range of flow is 105~132sccm.
Alternatively, first fluoro-gas is SF6、CF4、CHF3In one or more.
Alternatively, during etching first SiN layer, radio frequency power range is 1500~1900W, and pressure range is
130~210mTorr, bias power ranges are 90~110W, and the range of flow of first fluoro-gas is 20~45sccm.
Alternatively, second fluoro-gas is CH3F。
Alternatively, during etching remaining second SiN layer, radio frequency power range is 200~250W, and pressure range is
45~55mTorr, CH3F range of flow is 35~45sccm.
Alternatively, during etching remaining second SiN layer, the etching gas used also include O2, the O2Flow
Scope is 30~45sccm.
Alternatively, SiGe layer and the method for cavity are formed on the interlayer dielectric layer to be included：
Amorphous carbon layer is formed on the bottom crown；
Form SiGe layer, the SiGe layer covering amorphous carbon layer and interlayer dielectric layer；
Hole is formed in the SiGe layer upper surface, the hole exposes amorphous carbon layer；
Amorphous carbon layer is removed using cineration technics, cavity is formed in the position of corresponding amorphous carbon layer.
Alternatively, the thickness range of first SiN layer is
The present invention also provides a kind of pressure sensor, and the pressure sensor includes：
Substrate, on the substrate formed with transistor；
Interlayer dielectric layer, the interlayer dielectric layer cover the substrate and transistor, formed in the interlayer dielectric layer
There are bottom crown, the upper surface exposure of the bottom crown；
SiGe layer, the SiGe layer are located on the interlayer dielectric layer, had between the bottom crown and the SiGe
Cavity；
Etching stop layer in the SiGe layer, the first SiN layer on etching stop layer, the first SiN layer bag
Include the press section of corresponding empty cavity position and surround the edge part of the press section, the press section is spaced from each other with edge part, institute
State the SiGe layer exposure between press section and edge part.
Alternatively, the material of the etching stop layer is the first metal layer.
Alternatively, there is cushion, second on the cushion between the etching stop layer and SiGe layer
SiN layer；Or
There is the second SiN layer, the second gold medal in second SiN layer between the etching stop layer and SiGe layer
Belong to layer, the cushion in the second metal layer；Or
There is the second SiN layer, the second gold medal in second SiN layer between the etching stop layer and SiGe layer
Belong to layer, the 3rd SiN layer in the second metal layer, the cushion in the 3rd SiN layer.
Alternatively, the material of the cushion is SiGe, polysilicon or photoresist.
Alternatively, the thickness range of first SiN layer is
Compared with prior art, technical scheme has advantages below：
Etching stop layer is formed between SiGe layer and the first SiN layer.The first SiN layer to etching stop layer exposure is etched to stop
Only, the etching stop layer is etched untill SiGe layer, substantially will not over etching SiGe layer.It is, etching stop layer causes：
Under the conditions of the etching stop layer is etched, etching stop layer has very high etching selection ratio compared to SiGe layer, is etching
, substantially will not over etching SiGe layer after the etching stop layer of full depth.So, the SiGe layer as top crown will not be damaged
Wound, thickness meet expected definition.The capacitance for the capacitor that bottom crown and SiGe layer are formed meets expection, measures the obtained external world
Pressure value is accurate, and the reliability of pressure sensor improves, and performance is preferable.
Brief description of the drawings
Fig. 1~Fig. 4 is the cross-sectional view in the forming process of the pressure sensor switch of prior art
Fig. 5~Figure 11 is the cross-sectional view in the forming process of the pressure sensor of first embodiment of the invention；
Figure 12 is the top view of corresponding diagram 11；
Figure 13~Figure 14 is the cross-sectional view in the forming process of the pressure sensor of second embodiment of the invention.
Embodiment
The problem of existing for prior art is analyzed, reference picture 4, high fluoro-gas is used when etching SiN layer, such as
CF4、CHF3、SF6Deng the higher gas of fluorinated volume, there can be faster etch rate to SiN layer.But in identical etched rings
Under border, SiN and SiGe have close etching selection ratio, therefore after SiN layer is etched, inevitably over etching SiGe layer,
Dashed region is SiGe layer over etching part in figure.Attempting to pass through etching terminal（endpoint）Detection technique monitored quarter
SiGe layer phenomenon is lost, is not also succeeded.Moreover, form multiple similar pressure sensor knots when simultaneously synchronous on wafer
During structure, effective control can not be formed to the process for etching SiN layer, so the etching of the SiGe layer of each pressure sensor is lost
And it is inconsistent, otherness is very big.Therefore, the repeatability of the formation process of existing pressure sensor switch is not high.
Most of all, being changed by the thickness of the SiGe layer of over etching, the electric signal of pressure sensor can be influenceed,
Cause the predefined capacitance variation between bottom crown 31 and SiGe layer.When to the application of press section 52 ambient pressure, capacitance signal
Change it is no longer reliable, the ambient pressure value for measuring to obtain is no longer accurate, and the reliability of build-up of pressure sensor is not high, and performance is not
It is good.
It is understandable to enable the above objects, features and advantages of the present invention to become apparent, below in conjunction with the accompanying drawings to the present invention
Specific embodiment be described in detail.
First embodiment
Reference picture 5, there is provided substrate 100, formed with transistor 101 in substrate 100.The forming method of transistor 101 is
As it is known to those skilled in the art that it will not be repeated here.
In a particular embodiment, transistor 101, crystal are included formed with control circuit, the control circuit in substrate 100
Pipe 101 is used to receive electric capacity value signal, including electric capacity value signal is converted into pressure value by the control circuit of the transistor 101, is entered
And measure the pressure value for acting on pressure sensor.
In a particular embodiment, substrate 100 is silicon base, germanium substrate or silicon-on-insulator substrate etc.；Or substrate 100
Material can also include other materials, such as the compounds of group of GaAs etc. III-V.Those skilled in the art can basis
The transistor types selection substrate formed in substrate 100, therefore the type of substrate should not limit the scope of the invention.
Reference picture 6, forms interlayer dielectric layer 102, and interlayer dielectric layer 102 covers substrate 100 and transistor 101（Reference picture
5）, bottom crown 103, the upper surface exposure of bottom crown 103 are formed in interlayer dielectric layer 102；Shape is gone back in interlayer dielectric layer 102
Into having interconnection line 104, the exposure of the upper surface of interconnection line 104, interconnection line 104 is spaced from each other with bottom crown 103, the interconnection line 104
Electrically connected with bottom crown 103 with transistor.The interconnection line 104 and bottom crown 103 electrically connect with transistor, can be point
Source electrode, drain electrode not with transistor or grid is one-to-one electrically connects.
In a particular embodiment, the interconnection structure can be single or multiple lift interconnection structure, form the side of interconnection structure
Method is well known to those skilled in the art, and will not be repeated here.The material of bottom crown 103 is metal, can be with interlayer dielectric layer
The interconnection line 104 on 102 surfaces is formed in same processing step.
In a particular embodiment, the material of interlayer dielectric layer 102 is silica or other viable materials, uses chemical gaseous phase
Deposition is formed, and interlayer dielectric layer 102 plays the effect of being dielectrically separated from.
Reference picture 7, SiGe layer 105 is formed on interlayer dielectric layer 102, is formed between SiGe layer 105 and bottom crown 103
Cavity 106.
Cavity 106 separates SiGe layer 105 and bottom crown 103, and SiGe layer 105 forms a capacitor with bottom crown 103,
Top crown of the SiGe layer 105 as capacitor on cavity 106.The upper surface that SiGe layer 105 also exposes with interconnection line 104 connects
Touch, realize electrical connection, so, the top crown and bottom crown of capacitor electrically connect with transistor, when top crown is by ambient pressure
Cause condenser capacitance value changes, electric current is transferred to transistor, and control circuit converts the electrical signal to pressure value output.
In a particular embodiment, SiGe layer 105 and the method for cavity 106 are formed on interlayer dielectric layer 102 to be included：
Amorphous carbon layer is formed on bottom crown 103, amorphous carbon layer defines the position of cavity, can in specific implementation
To be first to deposit amorphous carbon material, amorphous carbon material covering interlayer dielectric layer 102, interconnection line 104 and bottom crown 103, it
Afterwards, amorphous carbon material is patterned to form amorphous carbon layer；
SiGe layer 105 is formed, specifically used chemical vapor deposition or physical vapour deposition (PVD), SiGe layer 105 cover amorphous
Carbon-coating, interlayer dielectric layer 102 and interconnection line 104；
Hole is formed in the upper surface of SiGe layer 105（Not shown in figure）, the hole exposes amorphous carbon layer；
Amorphous carbon layer is removed using cineration technics, cavity 106 is formed in the position of corresponding amorphous carbon layer.Specific real
Apply in example, the podzolic gas used in cineration technics is O2。O2Amorphous carbon layer is entered by the hole of the upper surface of SiGe layer 105, with
Amorphous carbon layer reaction generation escaping gas, escaping gas are discharged.
Reference picture 8, etching stop layer 107 is formed in SiGe layer 105, the first SiN layer is formed on etching stop layer 107
108.In the first SiN layer of subsequent etching 108, expose stopping to the upper surface of etching stop layer 107, etch etching stop layer 107
Expose up to SiGe layer 105, substantially will not over etching SiGe layer 105.
In a particular embodiment, etching stop layer 107 is formed in SiGe layer 105, the method for the first SiN layer 108 includes：
Etching stop layer 107 is the first metal layer, and the material of the first metal layer can be Ti, TiN, TaN or Ta, use thing
Physical vapor deposition, as sputtering technology forms etching stop layer 107；
The first SiN layer 108 is formed using chemical vapor deposition, the thickness range of the first SiN layer 108 isIf the thickness of the first SiN layer 108 is less thanFormed in the SiN layer of subsequent etching first
During press section, press section can not bear extraneous larger pressure；If the thickness of the first SiN layer 108 is more thanMay
Larger stress is formed to following SiGe layer, changes the shape of SiGe layer.
Reference picture 9, forms patterned mask layer 109 in the first SiN layer 108, and the patterned definition of mask layer 109 is pressed
The position of splenium, the material of patterned mask layer 109 can be photoresist or other viable materials；
Reference picture 10, it is mask with patterned mask layer 109, etches the first SiN layer 108（Reference picture 9）Form pressing
Portion 118 and the edge part 128 for surrounding press section 118, expose to the upper surface of etching stop layer 107, then, etch etching stop layer
107（Reference picture 9）, expose to SiGe layer 105.If not removing the etching stop layer between press section 118 and edge part 128,
When ambient atmos pressure is acted on etching stop layer, etching stop layer can stop that following SiGe layer deforms upon, and cause to press
Force snesor does not work.
Press section 118 and edge part 128 are spaced from each other, and are ring-shaped groove between press section 118 and edge part 128, are pressed
Splenium 118 and ring-shaped groove correspond to the position of cavity 106, as pressure sensor switch, are used in the process for etching the first SiN layer
Etching gas include the first fluoro-gas, wherein, the corresponding position of cavity 106 in press section 118 refers to that press section 118 is in cavity
The projection of plane where the upper surface of bottom crown 103 under 106, in the range of the upper surface of bottom crown；
In a particular embodiment, the fluorinated volume of the first fluoro-gas is higher, and the first fluoro-gas is SF6、CF4、CHF3In
It is one or more.The fluorinated volume refers to, in all atomicities of a gas molecule, fluorine atom number proportion.
Under etching condition using the first fluoro-gas, fluorine reacts generation volatile materials with SiN and is discharged, and the first SiN layer
With very high etch rate.
During the first SiN layer is etched, radio frequency power range is 1500~1900W, pressure range is 130~
210mTorr, bias power ranges are 90~110W, and the range of flow of first fluoro-gas is 20~45sccm.Specific
In embodiment, the first SiN layer process of etching is carried out in Ar environment, and Ar plays a part of completely cutting off air, vapor.
In a particular embodiment, the material of etching stop layer 107 is the metals such as Ti, TiN, TaN or Ta.In etching etch-stop
Only during layer 107, the etching gas used are Cl2、HBr、O2Mixed gas.Wherein, Cl2React and give birth to etching stop layer
Discharged into volatile materials, HBr is used to remove Cl2With the polymer of etching stop layer reaction generation, O2Etching speed can be lifted
Rate.Etching etching stop layer 107 to SiGe layer 105 exposes stopping, under conditions of etching stop layer is etched, etching stop layer phase
, substantially will not over etching SiGe layer, it is ensured that the SiGe layer as top crown is not than there is higher etching selection ratio in SiGe layer
Can by damage, thickness meets expected definition.So, the capacitance for the capacitor that bottom crown 103 and SiGe layer are formed meets pre-
Phase, capacitance variation is produced when ambient pressure acts on press section 118, the ambient pressure value for measuring to obtain is accurate, and pressure passes
The reliability of sensor improves, and performance is preferable.
Reference picture 11, Figure 12, Figure 12 are the top view of corresponding diagram 11, remove patterned mask layer.
The method for removing patterned mask layer, it can be selected according to the material of patterned mask layer.
Second embodiment
Reference picture 13, the second SiN layer 301 is formed in SiGe layer 300, cushion 302 is formed in the second SiN layer 301,
Etching stop layer 303 is formed on cushion 302, the first SiN layer 304 is formed on etching stop layer 303.
In the present embodiment, the material of etching stop layer 303 refers to the corresponding introduction of first embodiment.In view of etching
The material of stop-layer 303 is metal, has ductility, and the thickness of etching stop layer 303 can design very thin.If etch-stop
Only layer 303 is too thick, can reduce the sensitivity of pressure sensor.So, can be extremely short in subsequent etching etching stop layer process
Completed in time, the etch period is probably in 1s to 2s.In so short time range, whole etching process has hardly resulted in
Effect control, may form micro etching to following SiGe layer 300.
Therefore, to avoid causing micro etching to SiGe layer 300, before etching stop layer 303 is formed, in SiGe layer
Cushion 302 is formed on 300, cushion 302 plays cushioning effect during subsequent etching etching stop layer 303, etched
After complete etching stop layer 303, it may proceed to etch cushion 302.Compared to the single layer structure of etching stop layer, cushion, it is located at
The laminated construction thickness of etching stop layer on cushion is larger, relative can extend etch period so that whole etching process obtains
To effective control.In a particular embodiment, the material of cushion 302 makes the etch rate and etching of subsequent etching etching stop layer
The etch rate of cushion is essentially identical.The material of cushion 302 can be SiGe, polysilicon or photoresist.In the present embodiment
In, the material of cushion 302 is SiGe.
To avoid etching over etching SiGe layer 300 after cushion 302, therefore, before cushion 302 is formed, in SiGe
The second SiN layer 301 is formed on layer 300.
Reference picture 14, the first SiN layer 304 is patterned, forms press section 341 and surround the edge of press section 341
Portion 342, the position of the corresponding cavity 306 in press section 341, as pressure sensor switch, in the present embodiment, using photoetching, carve
Etching technique is patterned to the first SiN layer 304, and the etching gas used during the first SiN layer 304 is etched contain for first
Fluorine gas；
Then, after the first SiN layer 304 is etched, continue to etch etching stop layer 303, cushion 302 and segment thickness
Second SiN layer 301, the process of the second SiN layer 301 of etching etching stop layer 303, cushion 302 and segment thickness is same
Carried out in etching reaction chamber, under same etching condition；
Remaining second SiN layer 301 is etched, is exposed to SiGe layer 300, during etching remaining second SiN layer 301,
The etching gas used include the second fluoro-gas, and the fluorinated volume of the second fluoro-gas is less than the fluorinated volume of the first fluoro-gas.
In a particular embodiment, the parameters such as the process of the first SiN layer 304, the first fluoro-gas are etched and refers to the first implementation
The related introduction of etching the first SiN layer process of example.
In a particular embodiment, the second SiN layer 301 of etching stop layer 303, cushion 302 and segment thickness is etched
Process, it is identical with the parameter of the etching etching stop layer of first embodiment, can accordingly it refer to.
In the present embodiment, the fluorinated volume of the second fluoro-gas refers to that second contains less than the fluorinated volume of the first fluoro-gas
Number of fluorine atoms proportion in fluorine gas molecule, less than the number of fluorine atoms proportion in the first fluoro-gas molecule.Due to
First SiN layer 304 is more much bigger than the thickness of remaining second SiN layer 301, and when etching the first SiN layer 304, use is fluorine-containing
The first higher fluoro-gas of amount, can accelerate etch rate.And the very thin thickness of remaining second SiN layer 301, use are fluorine-containing
Measure the second low fluoro-gas and etch remaining second SiN layer 301, etch rate is relatively slow, can have to etching process
Effect monitoring, avoids causing over etching to SiGe layer 300.
In a particular embodiment, the second fluoro-gas is CH3F.During etching remaining second SiN layer 304, radio frequency
Power bracket is 200~250W, and pressure range is 45~55mTorr, CH3F range of flow is 35~45sccm.
In a particular embodiment, during etching remaining second SiN layer 304, the etching gas used also include O2, institute
State O2Range of flow be 30~45sccm.O2For being reacted with the second fluoro-gas and the second SiN layer in the polymer of generation
Carbon reaction generation CO2, CO, CO2, CO be discharged, realize remove polymer purpose.
In the present embodiment, the single layer structure formed with the second SiN layer 301 between cushion 302 and SiGe layer 300.
In other embodiments, the second SiN layer, the second gold medal in the second SiN layer are can also be between cushion and SiGe layer
Belong to the laminated construction of layer, or can be the second SiN layer, the second metal layer in the second SiN layer, positioned at second metal layer
On the 3rd SiN layer laminated construction, can according to implement needs be selected.
In addition in place of the difference with first embodiment, other unspecified interior perhaps alternatives of the present embodiment
First embodiment is referred to, is repeated no more in the present embodiment.
The present invention also provides a kind of pressure sensor.
First embodiment
Reference picture 11, Figure 12, the pressure sensor of the present embodiment include：
Substrate 100, formed with transistor in substrate 100（Non- label in figure）；
Interlayer dielectric layer 102, interlayer dielectric layer 102 cover substrate 100 and transistor, had in interlayer dielectric layer 102
There are bottom crown 103 and interconnection line 104, bottom crown 103 exposes, and interconnection line 104 and bottom crown 103 electrically connect with transistor；
SiGe layer 105, SiGe layer 105 cover interlayer dielectric layer 102, have sky between bottom crown 103 and SiGe layer 105
Chamber 106, SiGe layer 105 contact electrical connection with interconnection line 104, and such SiGe layer also electrically connects with transistor, bottom crown 103 and sky
SiGe layer on chamber 106 forms a capacitor；
Etching stop layer 107 in SiGe layer 105, the first SiN layer 108 on etching stop layer 107, first
SiN layer 108 includes the press section 118 of the corresponding position of cavity 106 and surrounds the edge part 128 of press section 118, the He of press section 118
Edge part 128 is spaced from each other, the SiGe layer part exposure between press section 118 and edge part 128.
Second embodiment
Be with the difference of first embodiment, in the present embodiment, reference picture 14, etching stop layer 303 with
There is the second SiN layer 301, the cushion 302 in the second SiN layer 301 between SiGe layer 300.On etching stop layer 303
First SiN layer 304 includes press section 341 and the edge part 342 around press section 341, press section 341 and edge part 342
It is spaced from each other, and SiGe layer exposure between the two, that is, cushion between press section 341 and edge part 342, second
SiN layer and etching stop layer are removed in forming process.
In other embodiments, can also be：There is the second SiN layer between etching stop layer and SiGe layer, positioned at the
The laminated construction of second metal layer in two SiN layers；Or there is the second SiN layer, position between etching stop layer and SiGe layer
In the second metal layer in second SiN layer, the 3rd SiN layer in the second metal layer, positioned at the 3rd SiN
Cushion on layer.
In a particular embodiment, the material of etching stop layer 303 is the first metal layer, the material of the first metal layer is Ti,
TiN, TaN or Ta.
In a particular embodiment, the material of cushion 302 is SiGe, polysilicon or photoresist.
In a particular embodiment, the thickness range of the first SiN layer 304 is
Although present disclosure is as above, the present invention is not limited to this.Any those skilled in the art, this is not being departed from
In the spirit and scope of invention, it can make various changes or modifications, therefore protection scope of the present invention should be with claim institute
The scope of restriction is defined.
Claims (20)
- A kind of 1. forming method of pressure sensor, it is characterised in that including：Substrate is provided, on the substrate formed with transistor；Interlayer dielectric layer is formed, the interlayer dielectric layer covers the substrate and transistor, formed in the interlayer dielectric layer There are bottom crown, the upper surface exposure of the bottom crown；SiGe layer is formed on the interlayer dielectric layer, cavity is formed between the SiGe layer and bottom crown；Etching stop layer is formed in the SiGe layer, the first SiN layer is formed on the etching stop layer, wherein, etch-stop Only layer is higher than the etching selection ratio of SiGe layer；Etch first SiN layer to form press section and surround the edge part of press section, showed to the etching stop layer upper table Go out, the press section is spaced from each other with edge part, and the press section corresponds to the empty cavity position, is etching first SiN layer The etching gas that use of process include the first fluoro-gas；The etching stop layer is etched, is exposed to SiGe layer.
- 2. the forming method of pressure sensor as claimed in claim 1, it is characterised in that the etching stop layer is the first gold medal Belong to layer.
- 3. the forming method of pressure sensor as claimed in claim 2, it is characterised in that the material of the first metal layer is Ti, TiN, TaN or Ta.
- 4. the forming method of pressure sensor as claimed in claim 2, it is characterised in that formed the etching stop layer it Before, the second SiN layer is formed in the SiGe layer, cushion is formed in second SiN layer；After the first SiN layer is etched, the second SiN layer of the etching stop layer, cushion and segment thickness is etched, cushion Material makes the etch rate of the etching etching stop layer identical with the etch rate for etching the cushion, etches cushion Etch rate is more than the etch rate of the second SiN layer of etching；Remaining second SiN layer is etched, is exposed to SiGe layer, etches the etching gas used during remaining second SiN layer Including the second fluoro-gas, the fluorinated volume of second fluoro-gas is less than the fluorinated volume of the first fluoro-gas.
- 5. the forming method of pressure sensor as claimed in claim 4, it is characterised in that before the cushion is formed, Second metal layer is formed in second SiN layer；OrBefore the cushion is formed, second metal layer, the shape in the second metal layer are formed in second SiN layer Into the 3rd SiN layer.
- 6. the forming method of pressure sensor as claimed in claim 4, it is characterised in that the material of the cushion is SiGe, polysilicon or photoresist.
- 7. the forming method of pressure sensor as claimed in claim 6, it is characterised in that etch the etching stop layer, delay The second SiN layer process of layer and segment thickness is rushed, the etching gas used are Cl2、HBr、O2Mixed gas.
- 8. the forming method of pressure sensor as claimed in claim 7, it is characterised in that etch the etching stop layer, delay Rushing the second SiN layer process of layer and segment thickness, radio frequency power range is 450~550W, pressure range is 9.5~ 10.5mTorr, bias power ranges are 54~66W, Cl2Range of flow be 105~132sccm, O2Range of flow for 3~ 5sccm, HBr range of flow are 105~132sccm.
- 9. the forming method of pressure sensor as claimed in claim 1, it is characterised in that first fluoro-gas is SF6、 CF4、CHF3In one or more.
- 10. the forming method of pressure sensor as claimed in claim 9, it is characterised in that etching the first SiN layer process In, radio frequency power range is 1500~1900W, and pressure range is 130~210mTorr, and bias power ranges are 90~110W, The range of flow of first fluoro-gas is 20~45sccm.
- 11. the forming method of pressure sensor as claimed in claim 4, it is characterised in that second fluoro-gas is CH3F。
- 12. the forming method of pressure sensor as claimed in claim 11, it is characterised in that remaining second SiN layer of etching During, radio frequency power range is 200~250W, and pressure range is 45~55mTorr, CH3F range of flow be 35~ 45sccm。
- 13. the forming method of pressure sensor as claimed in claim 12, it is characterised in that remaining second SiN layer of etching During, the etching gas used also include O2, the O2Range of flow be 30~45sccm.
- 14. the forming method of pressure sensor as claimed in claim 1, it is characterised in that the shape on the interlayer dielectric layer Method into SiGe layer and cavity includes：Amorphous carbon layer is formed on the bottom crown；Form SiGe layer, the SiGe layer covering amorphous carbon layer and interlayer dielectric layer；Hole is formed in the SiGe layer upper surface, the hole exposes amorphous carbon layer；Amorphous carbon layer is removed using cineration technics, cavity is formed in the position of corresponding amorphous carbon layer.
- 15. the forming method of pressure sensor as claimed in claim 1, it is characterised in that the thickness model of first SiN layer Enclose for
- A kind of 16. pressure sensor that method using described in claim 1 is formed, it is characterised in that including：Substrate, on the substrate formed with transistor；Interlayer dielectric layer, the interlayer dielectric layer covers the substrate and transistor, in the interlayer dielectric layer formed with Pole plate, the upper surface exposure of the bottom crown；SiGe layer, the SiGe layer are located on the interlayer dielectric layer, have cavity between the bottom crown and the SiGe；Etching stop layer in the SiGe layer, the first SiN layer on etching stop layer, wherein, etching stop layer It is higher than the etching selection ratio of SiGe layer；First SiN layer includes the press section of corresponding empty cavity position and surrounds the side of the press section Edge, the press section are spaced from each other with edge part, the SiGe layer exposure between the press section and edge part.
- 17. pressure sensor as claimed in claim 16, it is characterised in that the material of the etching stop layer is the first metal Layer.
- 18. pressure sensor as claimed in claim 17, it is characterised in that have between the etching stop layer and SiGe layer There are cushion, the second SiN layer on the cushion；OrThere is the second SiN layer, the second metal in second SiN layer between the etching stop layer and SiGe layer Layer, the cushion in the second metal layer；OrThere is the second SiN layer, the second metal in second SiN layer between the etching stop layer and SiGe layer Layer, the 3rd SiN layer in the second metal layer, the cushion in the 3rd SiN layer.
- 19. pressure sensor as claimed in claim 18, it is characterised in that the material of the cushion is SiGe, polysilicon Or photoresist.
- 20. pressure sensor as claimed in claim 16, it is characterised in that the thickness range of first SiN layer is
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| CN102954986A (en) * | 2011-08-16 | 2013-03-06 | Nxp股份有限公司 | Gas sensor |
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| CN1715850A (en) * | 2004-07-02 | 2006-01-04 | 阿尔卑斯电气株式会社 | Glass substrate and capacitance-type pressure sensor using the same |
| CN101087999A (en) * | 2004-12-22 | 2007-12-12 | 罗伯特·博世有限公司 | Micromechanical capacitive sensor element |
| CN101078663A (en) * | 2006-05-23 | 2007-11-28 | 森斯瑞股份公司 | Method for fabricating pressure sensor using SOI wafer |
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