CN111348618A - Method for reducing coupling interference of angle detection sensor of electrostatic micromirror - Google Patents
Method for reducing coupling interference of angle detection sensor of electrostatic micromirror Download PDFInfo
- Publication number
- CN111348618A CN111348618A CN202010021785.6A CN202010021785A CN111348618A CN 111348618 A CN111348618 A CN 111348618A CN 202010021785 A CN202010021785 A CN 202010021785A CN 111348618 A CN111348618 A CN 111348618A
- Authority
- CN
- China
- Prior art keywords
- micromirror
- coupling interference
- comb teeth
- electrostatic
- reducing coupling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00023—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems without movable or flexible elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
-
- 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
- B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
- B81C1/005—Bulk micromachining
-
- 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
- B81C1/00642—Manufacture or treatment of devices or systems in or on a substrate for improving the physical properties of a device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2201/00—Specific applications of microelectromechanical systems
- B81B2201/02—Sensors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C2201/00—Manufacture or treatment of microstructural devices or systems
- B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
- B81C2201/0101—Shaping material; Structuring the bulk substrate or layers on the substrate; Film patterning
- B81C2201/0111—Bulk micromachining
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Computer Hardware Design (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Micromachines (AREA)
- Mechanical Light Control Or Optical Switches (AREA)
Abstract
In order to improve the impedance of an equivalent coupling circuit and remarkably reduce the coupling interference of a driving signal to a detection signal, the invention provides a method for reducing the coupling interference of an electrostatic micromirror angle detection sensor, and particularly relates to a method for carrying out element doping on driving comb teeth and detection comb teeth of a micromirror and a lead wire area between the comb teeth and a bonding pad in the process of manufacturing the micromirror by adopting a high-resistivity semiconductor material, and then etching a micromirror structure to finally obtain the micromirror capable of reducing the coupling interference of the angle detection sensor. The method can obviously reduce the coupling interference of the driving signal in the electrostatic micromirror to the angle detection signal, improve the signal-to-noise ratio of the detection signal and reduce the complexity of a processing circuit. Meanwhile, the method of the invention does not need to change the structure of the micromirror, and greatly improves the control precision of the micromirror on the basis of the same structure and similar process difficulty.
Description
Technical Field
The invention relates to the field of micro-nano optical devices, in particular to a method for reducing coupling interference of an electrostatic micromirror angle detection sensor.
Background
The micro mirror is a micro-nano chip capable of effectively realizing light path regulation and is widely applied to the fields of projection, imaging, laser navigation and the like. The most widely used micromirrors include electrostatic, electromagnetic, piezoelectric, and electrothermal. Most of the prior micro mirrors adopt an open-loop control mode without angle feedback, and the micro mirror has the serious defect of lacking effective angle feedback to cause the problem of inaccurate control of the micro mirror, thereby causing the problems of projection and imaging drift, navigation deviation and the like. The prior partial micromirror adopts a certain angle feedback, but still has more problems.
In the currently used micromirror, an angle feedback method is to arrange an angle detection device outside the micromirror to measure the rotation angle of the micromirror, so that the angle feedback of the micromirror can be realized to a certain extent. For example, patent No. ZL200410085274.1 discloses a micromirror solution for angle measurement using optical components. However, in the detection device of the method, components such as a laser light source, a light path, a position sensor and the like need to be added into the micro-mirror module, so that the volume, the power consumption and the system complexity of the micro-mirror module are greatly increased. More importantly, due to factors such as installation errors, the detection method is difficult to realize accurate angle feedback, and the consistency of each micro mirror module is poor.
There are also proposals for angle detection using an angle sensor integrated in the micromirror, for example, a micromirror with electrothermal drive using plate capacitance detection is designed in the patent publication No. CN 109814251A. According to the scheme, a capacitor plate is arranged on a substrate, and the relation between the capacitance value on the capacitor plate and the actual torsion angle of the micro lens is used as a feedback value to perform signal feedback on a controller. The proposal reduces the components of the light path and the position sensor in the micro mirror module, and reduces the complexity of the micro mirror module to a certain extent. However, in the scheme, the flat electrode element is used as the angle feedback capacitor, the output of the feedback capacitor and the rotation angle of the micromirror have a nonlinear relation, the corresponding relation is complex, the output conversion speed is slow, the solution truncation error of the nonlinear relation is large, the flat electrode capacitor is small, the output signal is weak, the requirement on a processing circuit is high, and the signal-to-noise ratio is low. The proposal adopts an electrothermal driving mode, the working frequency of the micro mirror is low, and the micro mirror is difficult to be suitable for high-frequency scanning.
A piezoelectric driven micromirror Integrated with a piezoelectric angle sensor is disclosed in the paper "piezoelectric Actuated mirror Integrated with piezoelectric mirrors" (Key Engineering Materials 2011, 483:437 442). However, the piezoelectric driving and piezoelectric sensors are made of PZT materials, so that the process compatibility is poor, the processing difficulty is high, and the chip production line is easily polluted. Meanwhile, the piezoelectric sensor has extremely high requirements on the input impedance of a processing circuit, the circuit is complex, and the cost is high. Piezoelectric transducers have poor performance at low frequencies and are difficult to adapt for low frequency scanning of the micromirror.
There are also micromirror schemes that use electrostatic actuation in part and use capacitive sensors to provide angular feedback. The micromirror which is electrostatically driven and adopts the capacitive sensor for angle feedback can realize the integration of the angle detection sensor on the micromirror chip, and the system is simple, small in volume, low in power consumption, high in process compatibility and suitable for application from low frequency to high frequency. However, a serious problem of the current micromirror which is driven by static electricity and adopts a capacitive sensor to detect an angle is that a driving capacitor and a detection capacitor form a series capacitor circuit, a driving signal generates great coupling interference on a detection signal, the signal-to-noise ratio is very low, the detection precision is greatly reduced, and the requirement on a processing circuit of the detection signal is very high.
Disclosure of Invention
In order to solve the above problems, an object of the present invention is to provide a method for reducing coupling interference of an electrostatic micromirror angle detection sensor, which greatly increases impedance of an equivalent coupling circuit and significantly reduces coupling interference of a driving signal to a detection signal.
The realization process of the invention is as follows:
a method for reducing coupling interference of an electrostatic micromirror angle detection sensor is characterized in that in the process of manufacturing a micromirror by adopting a high-resistivity semiconductor material, element doping is carried out on driving comb teeth and detection comb teeth of the micromirror and lead wire areas between the comb teeth and a bonding pad, then the micromirror structure is etched, and finally the micromirror capable of reducing coupling interference of the angle detection sensor is obtained.
Further, the high-resistivity semiconductor material comprises monocrystalline silicon, polycrystalline silicon, amorphous silicon, silicon nitride, silicon carbide, silicon oxide and quartz, and the resistivity is greater than 1000 Ω & cm.
Further, the method of doping the element may be any one of ion implantation and diffusion.
Further, the doped element can be any one of boron, phosphorus or arsenic; the doped compound in the preparation process is any one of a boron-containing compound, a phosphorus-containing compound or an arsenic-containing compound.
Further, the doped compound may be any one of boron trifluoride, phosphane or arsane.
Further, after element doping, metal layer deposition is carried out on the driving comb teeth and the detecting comb teeth of the micromirror and the lead wire areas between the comb teeth and the bonding pad, then the micromirror structure is etched, and finally the micromirror capable of further reducing coupling interference of the angle detection sensor is obtained.
Further, the thickness of the metal layer is 20nm-1 μm.
Further, the method for depositing the metal layer can be any one of sputtering, evaporation or electroplating.
Further, the deposited metal can be any one or combination of chromium, gold, aluminum and copper.
Furthermore, the micro-mirror comprises two groups of driving comb teeth, a group of capacitance detection comb teeth and a bonding pad, and further comprises a static driving angle detection sensor or a capacitance angle detection sensor.
The document describes that "the electrostatic drive using the comb teeth can precisely control the torsion angle, and thus electrostatic angle detection can be inevitably achieved", but this argument is inconsistent with the scientific knowledge. The electrostatic driving is only a source of driving force, is a driving mode, and has no direct relation with precise control; it is further impossible to obtain "electrostatic angle detection is inevitably possible" because driving and detection are different links. If only electrostatic driving is carried out and a detection link is not arranged, the angle detection effect can not be obviously obtained; if the angle detection link is naturally obtained by adopting electrostatic driving, the scientific and technical common knowledge is violated. For the accurate control of the torsion angle, on one hand, the accuracy of a control signal is improved, and on the other hand, a feedback link is arranged; however, the two approaches are consistent no matter whether the electrostatic driving, the electromagnetic driving, the electrothermal driving, the piezoelectric driving or any other driving forms exist, and the control precision is not naturally improved due to the adoption of the electrostatic driving.
The low resistivity is completely independent of the reduction of coupling interference. Reducing coupling interference is achieved by specific circuit designs, and is not a necessary consequence of low resistivity; furthermore, high impedance modules are generally required rather than low resistance in circuits that reduce coupling interference. Furthermore, the step of doping elements in the invention is only used for manufacturing a lead in the structure for leading out signals, and the step of reducing the coupling interference is to form a high-resistance module through a high-resistivity structure so as to form an anti-interference coupling circuit with a capacitor, thereby realizing the effect of reducing the coupling interference, and is quite different from the effect of reducing the coupling interference through reducing the resistivity.
The micromirrors have various principles and designs and also various uses, and some micromirrors include capacitance detecting comb teeth or angle detecting sensors and some micromirrors do not include capacitance detecting comb teeth or angle detecting sensors according to specific principles, designs and uses.
In the prior art, various comb electrostatic driving micromirrors adopt low-resistivity silicon to manufacture a micromirror structure, and then a bonding pad is manufactured by depositing a metal layer on the surface of a micromirror fixing structure area for introducing driving signals, so that the whole micromirror structure has the characteristic of low resistance. Only some of the two-axis micromirrors implement isolation of the different conductive regions during fabrication, but the silicon wafers used for them are still low resistivity. The invention is different from the traditional comb electrostatic driving micro-mirror in principle and manufacturing method in that: the design of the whole electric conduction of the micro-mirror structure is completely abandoned, and the micro-mirror structure is made of high-resistivity materials; and doping and metal deposition are carried out only on the comb teeth and the lead wire area which need to be conductive to achieve the purpose of conductivity, and other structural areas keep a high-resistance state.
The invention has the following positive effects:
(1) the method can obviously reduce the coupling interference of the driving signal in the electrostatic micromirror to the angle detection signal, improve the signal-to-noise ratio of the detection signal and reduce the complexity of a processing circuit.
(2) Meanwhile, the method of the invention does not need to change the structure of the micromirror, and greatly improves the control precision of the micromirror on the basis of the same structure and similar process difficulty.
Drawings
FIG. 1 is a schematic diagram of a scheme for reducing coupling interference of a driving signal of an electrostatic driving micromirror to a detection signal according to the present invention;
FIG. 2 is an equivalent circuit of a conventional capacitive angle feedback electrostatic micromirror;
FIG. 3 is an equivalent circuit of the micromirror arrangement of the present invention;
FIG. 4 is a schematic structural view of embodiment 1;
FIG. 5 is a schematic structural view of embodiment 2;
fig. 6 is a schematic structural view of each step of the manufacturing method described in embodiment 3.
Detailed Description
The present invention will be further described with reference to the following examples.
In order to improve the impedance of an equivalent coupling circuit and obviously reduce the coupling interference of a driving signal to a detection signal, the invention provides a method for reducing the coupling interference of an electrostatic micromirror angle detection sensor.
As shown in fig. 1, the micromirror for angle detection by the electrostatic driving and capacitive sensor includes two sets of driving comb teeth 1, one set of capacitance detection comb teeth 2 and a bonding pad 3. The lead 4 is formed by doping elements in the comb-teeth portion and the lead region where the comb-teeth and the pad are connected. The drive comb teeth 1 and the detection comb teeth 2 are connected to respective ground pads through lead wires 4. The element is doped to reduce the resistivity of the doped region.
Because the drive comb teeth 1 and the detection comb teeth 2 are doped, the resistivity is reduced, capacitors with large capacity are formed in respective comb tooth array spaces of the drive comb teeth 1 and the detection comb teeth 2, and only high-resistance silicon connection exists between the drive comb teeth 1 and the detection comb teeth 2, a large resistor is formed between the drive comb teeth 1 and the detection comb teeth 2, so that the coupling interference of a drive signal to a detection signal caused by the capacitors between the drive comb teeth 1 and the detection comb teeth 2 is greatly reduced. The signal-to-noise ratio of the detection signal is remarkably improved, and the detection signal is used as feedback to be provided for the driving signal, so that the control precision of the micro-mirror is remarkably improved.
The specific principle of the invention for reducing the coupling interference of the driving signal to the detection signal is as follows:
the comb driving type micromirror with traditional capacitive angle feedback directly adopts low-resistance silicon to manufacture a structure, and the structure is taken as a circuit, and the equivalent circuit of the structure is shown in figure 2. Where Va ═ V0sin ω t is the drive signal, Vs1 is the coupling interference of the drive signal to the detection signal; c1 is a drive comb capacitor, C2 is a detection comb capacitor, and the coupling interference amount Vs1 of the drive signal to the detection signal is Va · C2/(C1+ C2) according to the principle of capacitance voltage division. The two sizes are equivalent in the comb-driven micromirror of the conventional capacitive angular feedback, and if C1 is equal to C2, Δ Vs1 is equal to Va/2. Generally, the amplitude of the driving signal Va is as high as tens of volts, and the magnitude of the detection signal Vs1 is only in the millivolt level, so the coupling interference caused by the driving signal to the detection signal is as high as thousands of times, the signal-to-noise ratio of the detection signal is as low as-60 dB, and the signal processing difficulty is extremely high.
This scheme adopts high resistant silicon preparation micro mirror structure, then adopts the doping mode to realize the circuit of drive broach, detection broach and lead wire, has increased a very big equivalent resistance between the electric capacity of drive broach and the electric capacity that detects the broach, as shown in fig. 3. According to the resistance-capacitance voltage division principle, coupling interference Vs2 caused by a driving signal to a detection signal is Va.XC 2/(XC1+ XC2+ R), wherein XC1 and XC2 are capacitance reactance of C1 and C2 respectively, C1 is C2 is C, XC1 is XC2 is 1/2 pi fC,where f is the drive signal frequency, C ═ N ε S/d, where N is the number of comb pairs, ε is the air dielectric constant, and the number is 8.85 × 10-12F/m; s is the comb tooth side area; d is the comb pitch. Compared with the traditional electrostatic micromirror with capacitive angle feedback, the scheme can obviously reduce the coupling interference of the driving signal to the detection signal.
EXAMPLE 1 micro-mirror design
As shown in FIG. 4, the mirror surface is circular, and the side of the mirror surface is provided with a first rotating comb 102 and a second rotating comb 104, which are respectively interlaced with a first fixed comb 101 and a third fixed comb 103 fixed on the peripheral frame to form two sets of driving combs. And a rotating shaft is arranged in the direction vertical to the connecting line of the rotating comb teeth, one end of the rotating shaft is connected with the circular mirror surface, and the other end of the rotating shaft is connected with the peripheral frame. The side of the rotating shaft is provided with a first movable detection comb 202, a second movable detection comb 204, a first movable balance comb 501 and a second movable balance comb 503. The first movable detection comb 202 and the second movable detection comb 204 are respectively staggered with the first fixed detection comb 201 and the second fixed detection comb 203 fixed on the peripheral frame to form two groups of detection combs. The first movable balance comb 502 and the second movable balance comb 504 are respectively staggered with the first fixed balance comb 501 and the second fixed balance comb 503 to form two groups of balance combs, and the balance combs have the function of ensuring structural symmetry and improving the control precision of the micro-mirror vibration. The peripheral frame is provided with a first driving pad 301, a second driving pad 302, a third driving pad 303, a first inspection pad 304, a second inspection pad 305 and a third inspection pad 306. Doping is performed on the drive and sense combs of the micromirror and the lead regions between the combs and the pad to reduce the resistivity of the doped region to 10-4Ω · cm, drive comb teeth, detection comb teeth, and other regions other than the lead region between these comb teeth and bonding pad are not doped, and the resistivity of the initial silicon wafer used for the entire micromirror is 106The resistivity of the area which is not doped is still kept at 106Omega cm. The doped comb teeth are connected with the corresponding bonding pads through leads 4. Drive comb, detection comb, pad area and corresponding lead area surface feedFirstly carrying out chromium metal simple substance deposition, and then carrying out gold metal simple substance deposition, wherein the thicknesses of the chromium layer are 20nm and the gold layer is 350nm respectively. In micromirror operation, voltage is applied through pads 301 and 302, pads 303 and 305 are grounded, and a detection signal is drawn from pads 304 and 306. Drive signals are transmitted only within the pads 301, 302, the fixed drive combs 101, 103 and the leads connecting 301 and 101, the leads connecting 302 and 103, and sense signals are transmitted only within the fixed sense combs 201, 203, the sense pads 304, 306 and the leads connecting 201 and 304, and connections 203 and 306. There is only high-impedance silicon (10) between the driving signal and the detection signal6Ω · cm), which is equivalent to increasing a huge resistance between the two loops, reducing the coupling interference of the driving signal to the detection signal, according to the resistive-capacitive voltage division principle, as shown in fig. 3, the coupling interference Vs2 ═ Va · XC2/(XC1+ XC2+ R) caused by the driving signal to the detection signal, where XC1 and XC2 are capacitive reactance of C1 and C2, respectively, C1 ═ C2 ═ C, XC1 ═ XC2 ═ 1/2 pi fC, where f is the driving signal frequency, in this embodiment, 1kHz, C ═ N ∈ S/d, where N is the number of comb teeth, in this embodiment, 100, and epsilon is the air dielectric constant, which is 8.85 × 10-12F/m; s is the comb tooth side area, 10 in this embodiment-8Square meter; d is the comb pitch, 10 in this example-6m. then XC 1-XC 2-1.8 × 107Omega. In the present embodiment, the micromirror made of high-resistance silicon has an equivalent resistance R of 100M Ω, and Vs2 of 0.076 Va. Compared with the conventional capacitive angle feedback electrostatic micromirror, the conventional micromirror (fig. 2) in which Vs1 is 0.5Va reduces the coupling interference of the driving signal to the detection signal by 92%.
EXAMPLE 2 micro-mirror design
As shown in fig. 5, a micromirror design is different from embodiment 1 in that the mirror surface is rectangular, all the driving comb teeth, the detecting comb teeth and the corresponding lead regions are doped, and then all the driving comb teeth, the detecting comb teeth, the pad regions and the corresponding lead regions are subjected to aluminum metal layer deposition with a thickness of 500 nm. According to the principle of resistance-capacitance voltage division, coupling interference Vs2 caused by a driving signal to a detection signal is Va.XC 2/(XC1+ XC2+ R), wherein XC1 and XC2 are capacitance reactance of C1 and C2 respectively, C1 is C2 is C, XC1 is XC2 is 1/2 pi fC,where f is the drive signal frequency, 2kHz in this example, C ═ N ∈ S/d, where N is the number of comb tooth pairs, 100 in this example, and ∈ is the air dielectric constant, with a value of 8.85 × 10-12F/m, S is the comb tooth side area, 2 × 10 in this example-8Square meter; d is the comb pitch, 10 in this example-6m. then XC1 ═ XC2 ═ 4.5 × 106Omega. In this embodiment, the micromirror made of quartz has an equivalent resistance R of 1G Ω, and Vs2 of 0.0045 Va. Compared with the conventional capacitive angle feedback electrostatic micromirror, the scheme reduces the coupling interference of the driving signal to the detection signal by 99.1% in the conventional micromirror (see fig. 2) in which Vs1 is 0.5 Va.
EXAMPLE 3 micromirror fabrication method
To better illustrate the method of fabricating the micromirror of the present invention, a specific process is illustrated after the existing fabrication method is added to the method of the present invention. As shown in fig. 6
A method for manufacturing a micromirror capable of reducing coupling interference of an electrostatic micromirror angle detection sensor comprises:
(1) an SOI (silicon on insulator) silicon wafer is prepared. The SOI silicon wafer comprises three layers of base silicon 701, a buried oxide layer 702 and top silicon 703 from bottom to top. The substrate silicon 701 and the top layer silicon 703 are high-resistance silicon with resistivity ranging from 1 to 108Omega cm. The thickness of the substrate silicon 701 is 100-800 μm, the thickness of the buried oxide layer is 0.5-10 μm, and the thickness of the top layer is 5-100 μm. Preferably, the base silicon 701 is 400 μm thick, the buried oxide layer 702 is 4 μm thick, and the top silicon 703 is 50 μm thick. Preferably, the resistivity of the base silicon 701 and the top silicon 703 is 10 here4Ω cm, see fig. 6 a.
(2) The lead areas are defined by front side lithography. And photoetching the front side to obtain a lead area pattern, wherein the photoresist is used as a masking layer for subsequently manufacturing a lead 7031, as shown in fig. 6 b.
(3) And manufacturing a front lead. Doping the silicon wafer obtained in the last step by adopting an ion implantation method, wherein the doping element is boron, and the area resistivity of the doped silicon wafer is reduced to 10-2Ω · cm, forming a lead 7031. It should be noted that the doped regions in this step are only the lithographically defined lead regions, which occupy only a small portion of the total silicon areaThe regions remaining covered by the photoresist remain in the high resistivity state. The doping element may be boron, phosphorus or arsenic. The doping method may be ion implantation or diffusion. The ion implantation is adopted, and the boron used is a compound containing boron, and can be boron trifluoride; the compound of phosphorus may be phosphane and the compound of arsenic may be arsane, see figure 6 c.
(4) And manufacturing a metal layer on the front surface. Firstly, photoetching to obtain a metal making pattern, then sputtering Cr30nm, sputtering Au300nm, and finally soaking a silicon wafer in acetone to remove photoresist to obtain the required metal layer 7032. The metal layer 7032 covers the area including the comb teeth, the portion of the lead portion for reducing resistance, and the pad portion. The metal layer can be formed by sputtering, evaporation or electroplating. The metal layer can be chromium, gold, aluminum and copper, and can also be a combination of several metals. A chrome gold combination is used here. The thickness of the metal layer is 20nm-1 μm. The deposition of the metal layer can further reduce the resistivity of the comb tooth portions and increase the conductive area of the comb tooth portions, see fig. 6 d.
(5) And etching the front surface by a deep dry method. And the front side adopts photoresist as an etching masking layer, a deep dry etching method is adopted to manufacture a front deep groove structure 7033, and the etching is stopped until the buried oxide layer 702 is etched. Masking layers that may be used for the front side etch include photoresist, silicon oxide, silicon nitride, metal layers, etc., see fig. 6 e.
(6) And (4) protecting the front surface. The front side is coated with polyamide as the front side protective layer 800 after the front side deep dry etching is completed. The protective layer 800 may be a polymer material such as polyamide, polyimide, polymethyl methacrylate, etc., see fig. 6 f.
(7) And etching the back surface. And (3) reversing the silicon wafer, performing deep dry etching on the back by using silicon oxide and silicon nitride as etching masking layers, and stopping etching until the buried oxide layer 702 is etched to obtain a back cavity structure 7011, which is shown in fig. 6 g.
(8) And (4) releasing. And removing the exposed buried oxide layer 702 after etching by adopting hydrogen fluoride gas, and then removing the polyamide protective layer 800 on the front surface of the silicon wafer by adopting oxygen plasma to obtain the finished silicon wafer, wherein the step is shown in figure 6 h.
The above steps are preferred methods. The sequence of some steps can be interchanged, and alternative processes can be adopted to achieve the same effect.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and is not intended to limit the invention to the particular forms disclosed. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (10)
1. A method for reducing coupling interference of an electrostatic micromirror angle detection sensor is characterized in that a micromirror is manufactured by adopting a high-resistivity semiconductor material, and the manufacturing steps comprise doping comb teeth and a lead wire area, depositing metal on the comb teeth, the lead wire area and a bonding pad area, etching a micromirror structure layer and etching a micromirror substrate; and in the manufacturing process, element doping is carried out on the driving comb teeth and the detection comb teeth of the micromirror and the lead wire areas between the comb teeth and the bonding pad, then the micromirror structure is etched, and finally the micromirror capable of reducing the coupling interference of the angle detection sensor is obtained.
2. The method of claim 1, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: the high-resistivity semiconductor material comprises monocrystalline silicon, polycrystalline silicon, amorphous silicon, silicon nitride, silicon carbide, silicon oxide and quartz, and the resistivity is greater than 1000 omega cm.
3. The method of claim 1, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: the element doping method may be any one of ion implantation and diffusion.
4. The method of claim 1, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: the doped element can be any one of boron, phosphorus or arsenic; the doped compound in the preparation process is any one of a boron-containing compound, a phosphorus-containing compound or an arsenic-containing compound.
5. The method of claim 4, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: the doped compound may be any one of boron trifluoride, phosphane or arsane.
6. The method of claim 1, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: after element doping, metal layer deposition is carried out on the driving comb teeth and the detection comb teeth of the micromirror and the lead wire area between the comb teeth and the bonding pad, then the micromirror structure is etched, and finally the micromirror capable of further reducing coupling interference of the angle detection sensor is obtained.
7. The method of claim 6, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: the thickness of the metal layer is 20nm-1 μm.
8. The method of claim 6, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: the metal layer can be deposited by any one of sputtering, evaporation and electroplating.
9. The method of claim 6, wherein the step of reducing coupling interference of the electrostatic micromirror angle detecting sensor comprises: the deposited metal can be any one or combination of chromium, gold, aluminum and copper.
10. The method of reducing coupling interference of an electrostatic micromirror angle detecting sensor according to any one of claims 1 to 9, wherein: the micro-mirror comprises two groups of driving comb teeth, one group of capacitance detection comb teeth and a bonding pad, and further comprises an electrostatic driving angle detection sensor or a capacitance type angle detection sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010021785.6A CN111348618B (en) | 2020-01-09 | 2020-01-09 | Method for reducing coupling interference of electrostatic micro-mirror angle detection sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010021785.6A CN111348618B (en) | 2020-01-09 | 2020-01-09 | Method for reducing coupling interference of electrostatic micro-mirror angle detection sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111348618A true CN111348618A (en) | 2020-06-30 |
| CN111348618B CN111348618B (en) | 2023-07-11 |
Family
ID=71190499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010021785.6A Active CN111348618B (en) | 2020-01-09 | 2020-01-09 | Method for reducing coupling interference of electrostatic micro-mirror angle detection sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111348618B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112965239A (en) * | 2021-02-05 | 2021-06-15 | 西安知象光电科技有限公司 | Stacked induction capacitor angle feedback galvanometer and manufacturing method thereof |
| CN114019675A (en) * | 2021-09-29 | 2022-02-08 | 北京理工大学 | Two-dimensional micromirror |
| US20220066197A1 (en) * | 2020-09-01 | 2022-03-03 | Beijing Voyager Technology Co., Ltd. | Capacitance sensing in a mems mirror structure |
| CN116699834A (en) * | 2023-07-31 | 2023-09-05 | 西安知象光电科技有限公司 | Micro-vibrating mirror structure based on staggered vertical comb tooth driving array and preparation process thereof |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1969217A (en) * | 2005-01-05 | 2007-05-23 | 日本电信电话株式会社 | Mirror device, mirror array, optical switch, and manufacturing method thereof |
| CN101228093A (en) * | 2005-07-22 | 2008-07-23 | 高通股份有限公司 | MEMS devices having support structures and methods of fabricating the same |
| CN101907769A (en) * | 2010-07-01 | 2010-12-08 | 西北工业大学 | Silicon on insulator (SOI) wafer double-mask etching-based vertical comb teeth driven torsional micro-mirror and manufacturing method thereof |
| US20110136283A1 (en) * | 2001-12-13 | 2011-06-09 | Joseph E. Ford | Process for fabricating MEMS devices |
| CN105336751A (en) * | 2014-06-23 | 2016-02-17 | 上海箩箕技术有限公司 | Photoelectric sensor and manufacturing method thereof |
| US20160280534A1 (en) * | 2015-03-25 | 2016-09-29 | Robert Bosch Gmbh | Capacitive mems-sensor element having bond pads for the electrical contacting of the measuring capacitor electrodes |
| CN107976871A (en) * | 2017-11-10 | 2018-05-01 | 无锡英菲感知技术有限公司 | A kind of controllable micro mirror minute surface comb structure of dynamic deformation and its processing method |
| CN110543010A (en) * | 2019-08-23 | 2019-12-06 | 中国科学院高能物理研究所 | Ultra-precise active optical modulation method and system based on multi-interval thermal deformation modulation |
| US20210140767A1 (en) * | 2017-06-16 | 2021-05-13 | Societe de Commercialisation des Produits de la Recherche Appliquée Socpra Sciences et Génie S.E.C. | Inertial devices with wafer-level integration of higher density proof masses and method of manufacturing |
-
2020
- 2020-01-09 CN CN202010021785.6A patent/CN111348618B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110136283A1 (en) * | 2001-12-13 | 2011-06-09 | Joseph E. Ford | Process for fabricating MEMS devices |
| CN1969217A (en) * | 2005-01-05 | 2007-05-23 | 日本电信电话株式会社 | Mirror device, mirror array, optical switch, and manufacturing method thereof |
| CN101228093A (en) * | 2005-07-22 | 2008-07-23 | 高通股份有限公司 | MEMS devices having support structures and methods of fabricating the same |
| CN101907769A (en) * | 2010-07-01 | 2010-12-08 | 西北工业大学 | Silicon on insulator (SOI) wafer double-mask etching-based vertical comb teeth driven torsional micro-mirror and manufacturing method thereof |
| CN105336751A (en) * | 2014-06-23 | 2016-02-17 | 上海箩箕技术有限公司 | Photoelectric sensor and manufacturing method thereof |
| US20160280534A1 (en) * | 2015-03-25 | 2016-09-29 | Robert Bosch Gmbh | Capacitive mems-sensor element having bond pads for the electrical contacting of the measuring capacitor electrodes |
| US20210140767A1 (en) * | 2017-06-16 | 2021-05-13 | Societe de Commercialisation des Produits de la Recherche Appliquée Socpra Sciences et Génie S.E.C. | Inertial devices with wafer-level integration of higher density proof masses and method of manufacturing |
| CN107976871A (en) * | 2017-11-10 | 2018-05-01 | 无锡英菲感知技术有限公司 | A kind of controllable micro mirror minute surface comb structure of dynamic deformation and its processing method |
| CN110543010A (en) * | 2019-08-23 | 2019-12-06 | 中国科学院高能物理研究所 | Ultra-precise active optical modulation method and system based on multi-interval thermal deformation modulation |
Non-Patent Citations (1)
| Title |
|---|
| A. PIOTROWSKA\N\N\N\N,A.GUIVARCH\N\N\N\N,G.PELOUS\N\N\N\N,沈家树\N\N\N\N,李庆文: "Ⅲ―Ⅴ旗化合物半导体欧姆接触制作技术评述" * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220066197A1 (en) * | 2020-09-01 | 2022-03-03 | Beijing Voyager Technology Co., Ltd. | Capacitance sensing in a mems mirror structure |
| US11789253B2 (en) * | 2020-09-01 | 2023-10-17 | Beijing Voyager Technology Co., Ltd. | Capacitance sensing in a MEMS mirror structure |
| CN112965239A (en) * | 2021-02-05 | 2021-06-15 | 西安知象光电科技有限公司 | Stacked induction capacitor angle feedback galvanometer and manufacturing method thereof |
| CN114019675A (en) * | 2021-09-29 | 2022-02-08 | 北京理工大学 | Two-dimensional micromirror |
| CN114019675B (en) * | 2021-09-29 | 2022-11-01 | 北京理工大学 | Two-dimensional micromirror |
| CN116699834A (en) * | 2023-07-31 | 2023-09-05 | 西安知象光电科技有限公司 | Micro-vibrating mirror structure based on staggered vertical comb tooth driving array and preparation process thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111348618B (en) | 2023-07-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111348618A (en) | Method for reducing coupling interference of angle detection sensor of electrostatic micromirror | |
| US6888662B2 (en) | Micro-mechanical system employing electrostatic actuator and fabrication methods of same | |
| US20030048036A1 (en) | MEMS comb-finger actuator | |
| CN1987486B (en) | Integrated optic grating interference micro mechanical acceleration sensor and its producing method | |
| CN111204701B (en) | Micro-mirror with fully symmetrical differential capacitance angle feedback | |
| CN113702665B (en) | MEMS accelerometer and forming method thereof | |
| CN116026501B (en) | Pressure sensor and manufacturing method thereof | |
| JP2002112560A (en) | Electrostatic actuator and camera module employing the actuator | |
| CN114323396B (en) | MEMS capacitive six-axis force sensor chip and preparation process thereof | |
| CN109437089B (en) | Manufacturing process flow of micro electric field sensor with cantilever beam structure | |
| CN113960782A (en) | Electrostatic MEMS micro-mirror with piezoresistive feedback and manufacturing method | |
| CN1291232C (en) | Minitype angular velocity sensor and its making method | |
| CN116086420B (en) | Vibrating ring MEMS gyroscope and manufacturing method thereof | |
| CN114296014B (en) | Lorentz force-based three-dimensional MEMS magnetic field sensor and preparation method thereof | |
| CN112965239B (en) | Stacked induction capacitor angle feedback galvanometer and manufacturing method thereof | |
| CN100570430C (en) | Little level crossing of the variable focal point of static driven and manufacture method thereof | |
| US6204086B1 (en) | Method for manufacturing semiconductor components having micromechanical structures | |
| CN103149683B (en) | One-direction torsion and high-balance variable optical attenuator and preparation method thereof | |
| JPH10313123A (en) | Transducer using thin film and manufacture thereof | |
| KR100300965B1 (en) | Micro mirror actuator and Fabricating method thereof | |
| CN112198412A (en) | Test structure and preparation method thereof | |
| CN216434535U (en) | Electrostatic MEMS micro-mirror with piezoresistive feedback | |
| CN110514188B (en) | Gyroscope and method for correcting quadrature error of gyroscope by process | |
| CN116358764A (en) | Triaxial MEMS force sensor with self-calibration function | |
| CN114383762B (en) | MEMS capacitive micro-force sensor based on multi-comb array and decoupling test method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |