Acceleration sensor sensitive component and acceleration sensor chip structure

Abstract

The application provides an acceleration sensor sensitive component and an acceleration sensor chip structure, wherein the acceleration sensor sensitive component comprises a substrate, an elastic beam and an electrothermal driving beam; the elastic beam is mounted on the substrate and is fixedly connected with a frame; the frame is provided with a first comb tooth part; the first comb tooth part comprises a plurality of first sub-comb teeth which are arranged at intervals; comb tooth gaps are formed between any adjacent first sub-comb teeth; the electrothermal driving beam is mounted on the substrate and is located in the frame; the electrothermal driving beam is fixedly connected with a support; the support is provided with a second comb tooth part; the second comb tooth part comprises a plurality of second sub-comb teeth which are arranged at intervals; and the second sub-comb teeth are located in the comb tooth gaps respectively. The acceleration sensitive component provided by the application changes the comb tooth gap, so that the comb tooth gap is reduced to several hundred nanometers or even several tens of nanometers, and the sensitivity of the acceleration sensor is improved; the zero offset of the acceleration sensor sensitive component can be calibrated; in addition, the structure is compact and the cost is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to an acceleration sensor sensitive component and an acceleration sensor chip structure. BACKGROUND

[0002] The capacitive acceleration sensing chip is a kind of acceleration sensor based on micro-nano manufacturing process, which can measure the acceleration of an object and convert it into an electrical signal output. The capacitive acceleration sensing chip is widely used in consumer electronics, automotive electronics, industry, national defense and other fields.

[0003] The working principle of the capacitive acceleration sensing chip is based on the detection of capacitance change. It is usually composed of a micro-electro-mechanical system chip and a signal processing circuit. The chip contains a small mechanical structure, and the common capacitive acceleration sensing chip structure includes: micro-comb tooth capacitance, micro-flat plate capacitance, etc. When subjected to acceleration, these microstructures will produce a small displacement, resulting in a change in capacitance between the electrodes. This change can be measured and processed by the circuit to obtain the information of acceleration.

[0004] In the comb tooth capacitance structure of the acceleration sensing chip, the comb tooth gap plays a decisive role in the capacitance value. The comb tooth structure is composed of two sets of nested electrodes, one set of electrodes has a series of comb teeth, and the other set of electrodes has a corresponding number of comb teeth. The comb tooth gap is a series of parallel capacitance gaps formed between the two sets of electrodes. The size of the comb tooth gap directly affects the size of the capacitance value. Smaller comb tooth gap will result in larger capacitance value, thus obtaining higher structural sensitivity under the premise of constant structural stiffness. Therefore, for the capacitive acceleration sensing chip, the smaller the comb tooth gap is, the better.

[0005] In order to improve the sensitivity of the capacitive acceleration sensor chip, in the prior art, the first way is to use higher precision photolithography technology and higher aspect ratio etching technology. Through this method, under the condition of good process control, a comb tooth gap of about 1-5 microns and a comb tooth capacitance with an aspect ratio of about 10-20 can be processed. However, it is difficult to process a comb tooth capacitance structure with a comb tooth gap less than 1 micron by this method. The second way is to use high aspect ratio polycrystalline silicon-single crystal silicon composite etching process. This process can realize a comb tooth capacitance structure with a comb tooth gap of hundreds of nanometers by making a polycrystalline silicon and silicon oxide structure layer on a single crystal silicon structure. However, this manufacturing method has a complex process flow, high manufacturing cost, and requires very fine process control.

[0006] In summary, the prior art has the following disadvantages: high processing technology requirement and complex processing technology, high manufacturing cost, and poor acceleration sensor sensitivity. SUMMARY

[0007] The first aspect of the present application provides an acceleration sensor sensitive component, which solves the technical problems of high requirement and complex processing technology, high manufacturing cost and poor sensitivity of the acceleration sensor in the prior art.

[0008] The first aspect of the present application provides an acceleration sensor sensitive component, which solves the technical problems of high requirement and complex processing technology, high manufacturing cost and poor sensitivity of the acceleration sensor in the prior art.

[0009] The substrate;

[0010] The elastic beam is mounted on the substrate and fixed with a frame, the frame is provided with a first comb tooth part, the first comb tooth part includes a plurality of first sub-comb teeth arranged at intervals, and a comb tooth slot is formed between any adjacent first sub-comb teeth.

[0011] The electrothermal driving beam is mounted on the substrate and located in the frame, the electrothermal driving beam is fixed with a support, the support is provided with a second comb tooth part, the second comb tooth part includes a plurality of second sub-comb teeth arranged at intervals, and the second sub-comb teeth are respectively located in the comb tooth slots.

[0012] The acceleration sensor sensitive component provided by the present application changes the comb tooth gap by arranging the first comb tooth part connected with the elastic beam and the second comb tooth part connected with the electrothermal driving beam, reduces the comb tooth gap to hundreds of nanometers or even tens of nanometers, improves the sensitivity of the comb tooth capacitor to the external acceleration by 2-3 orders of magnitude, and can realize the sensing of 10 -6 -10 -8 gravity acceleration, improves the sensitivity of the acceleration sensor, can calibrate the zero offset of the acceleration sensor sensitive component by adjusting the driving voltage of the electrothermal driving beam, and has the advantages of compact structure, low cost, simple processing and manufacturing process, and low processing requirement.

[0013] Further, the number of the elastic beams is two and they are oppositely arranged, and the two ends of the frame are respectively fixed to the elastic beams.

[0014] Further, the frame is a mouth-shaped structure or an I-shaped structure, the frame includes a first connecting plate, a second connecting plate and a support frame fixed between the two, one of the elastic beams is fixed to the first connecting plate, the other elastic beam is fixed to the second connecting plate, and a plurality of first sub-comb teeth are fixed to the support frame.

[0015] Further, the support frame is fixed with a first comb tooth mounting plate, and a plurality of first sub-comb teeth are fixed to the first comb tooth mounting plate.

[0016] Further, the number of the electrothermal driving beams is two and they are oppositely arranged, and the two ends of the support are respectively fixed to the electrothermal driving beams.

[0017] And / or, the cross-sectional shape of the electrothermal driving beam is at least one of V-shaped, N-shaped and A-shaped.

[0018] And / or, the electrothermal driving beam comprises a plurality of groups of electrothermal sub-driving beams arranged in parallel.

[0019] The second aspect of the present application provides an acceleration sensor chip structure, comprising a shell and the acceleration sensor sensitive assembly in any one of the claims, the acceleration sensor sensitive assembly is arranged in the shell, the shell is also provided with a temperature control assembly and a controller, the temperature control assembly comprises a temperature sensor and a temperature control component, the temperature sensor and the temperature control component are electrically connected with the controller, the temperature sensor is used to detect the temperature value in the shell, and the controller is used to receive the temperature value and control the temperature control component to make the temperature value in a preset temperature range.

[0020] The acceleration sensor chip structure provided by the embodiment of the present application can control the temperature in the shell in the preset temperature range through the temperature sensor and the temperature control component electrically connected with the controller, so as to ensure the sensitivity of the acceleration sensor sensitive assembly; the temperature drift calibration of the acceleration sensor chip structure can be realized; in addition, the acceleration sensor sensitive assembly is provided with the first comb tooth part connected with the elastic beam and the second comb tooth part connected with the electrothermal driving beam, the change of the comb tooth gap is realized, the comb tooth gap is reduced to hundreds of nanometers or even tens of nanometers, the sensitivity of the comb tooth capacitor to the external acceleration is improved by 2-3 orders of magnitude, the sensing of the gravitational acceleration can be realized, and the sensitivity of the acceleration sensor is improved; the zero offset calibration of the acceleration sensor sensitive assembly can be realized by adjusting the driving voltage of the electrothermal driving beam; the structure design is compact, the cost is low, the manufacturing process is simple, and the processing technology requirement is low.

[0021] Further, the temperature control component comprises a heating component for increasing the temperature in the shell.

[0022] Further, the shell is also provided with a capacitance readout circuit assembly for converting the capacitance value of the acceleration sensor sensitive assembly into a voltage value.

[0023] Further, the controller is installed on the substrate;

[0024] And / or, the temperature sensor is installed on the substrate;

[0025] And / or, the heating component is installed on the substrate;

[0026] And / or, the capacitance readout circuit assembly is installed on the substrate.

[0027] Further, the temperature sensor is mounted on the acceleration sensor sensitive component. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 An exploded structural schematic view of the acceleration sensor sensitive component provided by the embodiment of the present application is shown in Fig. 1.

[0029] Figure 2 A structural schematic view of the acceleration sensor sensitive component provided by the embodiment of the present application is shown in Fig. 2.

[0030] Figure 3 A structural schematic view of the N-type electrothermal driving beam in the acceleration sensor sensitive component provided by the embodiment of the present application is shown in Fig. 3.

[0031] Figure 4 A structural schematic view of the A-type electrothermal driving beam in the acceleration sensor sensitive component provided by the embodiment of the present application is shown in Fig. 4.

[0032] Figure 5 A structural schematic view of the acceleration sensor chip structure provided by the embodiment of the present application is shown in Fig. 5.

[0033] BRIEF DESCRIPTION OF DRAWINGS

[0034] 10, acceleration sensor sensitive component; 100, substrate; 110, elastic beam; 120, frame; 121, first connecting plate; 122, second connecting plate; 123, support frame; 124, first comb tooth mounting plate; 130, first comb tooth part; 131, first sub-comb tooth; 132, comb tooth slot; 140, electrothermal driving beam; 150, support; 160, second comb tooth part; 161, second sub-comb tooth; 1, shell; 21, temperature sensor; 30, controller; 40, capacitance readout circuit component; 50, resistance-capacitance device. DETAILED DESCRIPTION

[0035] In order to make the above objectives, features and advantages of the present application more apparent, more comprehensible and more understandable, the following will combine the attached drawings for the specific implementation of the present application with the detailed description of the present application. Figures 1-5 The specific embodiments of the present application will be described in detail.

[0036] The embodiment of the present application provides an acceleration sensor sensitive component. Referring to the attached Figure 1 and 2The acceleration sensor sensitive component 10 comprises a substrate 100, an elastic beam 110 and an electrothermal driving beam 140; wherein the elastic beam 110 is mounted on the substrate 100 and is fixedly connected with a frame 120, the frame 120 is provided with a first comb tooth part 130, the first comb tooth part 130 comprises a plurality of first sub-comb teeth 131 arranged at intervals, and a comb tooth slot 132 is formed between any adjacent first sub-comb teeth 131; the electrothermal driving beam 140 is mounted on the substrate 100 and is located in the frame 120, the electrothermal driving beam 140 is fixedly connected with a support 150, the support 150 is provided with a second comb tooth part 160, the second comb tooth part 160 comprises a plurality of second sub-comb teeth 161 arranged at intervals, and the second sub-comb teeth 161 are respectively located in the comb tooth slots 132.

[0037] It should be noted that the second sub-comb teeth 161 are respectively located in the comb tooth slots 132 to form first and second capacitors, and the first and second capacitors constitute a differential capacitor; under the action of external acceleration, the elastic beam 110 can drive the frame 120 to produce elastic displacement, drive the first sub-comb teeth 131 to move, cause one of the first and second capacitors to increase and the other to decrease, thereby changing the size of the differential comb tooth capacitor and achieving the effect of acceleration sensitivity.

[0038] It should be noted that the electrothermal driving beam 140 has a low-sensitivity working state and a high-sensitivity working state; if in the low-sensitivity working state, the electrothermal driving beam 140 does not apply an electrothermal driving voltage, the second sub-comb teeth 161 do not move, the second sub-comb teeth 161 have a larger stroke, that is, the acceleration sensor has a larger range and a lower sensitivity; if in the high-sensitivity working state, the electrothermal driving beam 140 applies an electrothermal driving voltage, heats the electrothermal driving beam 140 through Joule heat, drives the second sub-comb teeth 161 to move, thereby changing the gap between the second sub-comb teeth 161 and the comb tooth slots 132, so that the comb tooth gap is reduced to hundreds or even tens of nanometers, causing one of the first and second capacitors to further increase and the other to further decrease, thereby increasing the initial capacitor size of the differential comb tooth capacitor and improving the sensitivity of the acceleration sensor structure.

[0039] It should be noted that the electrothermal driving beam 140 drives the second sub-comb teeth 161 to move, further reducing the gap between the second sub-comb teeth 162 and the comb tooth slots 132, compared with the prior art which relies on high processing technology to process a comb tooth gap of 1-5 microns, the processing technology requirement is low and the processing and manufacturing process is simple.

[0040] It should be noted that when the acceleration sensor is in a static state, whether there is a zero offset of the acceleration sensor at this time can be detected; if there is a zero offset, the driving voltage of the electrothermal driving beam 140 can be adjusted so that the acceleration sensor sensitive component 10 is in a position of zero potential, thereby realizing zero offset calibration of the acceleration sensor.

[0041] Therefore, the acceleration sensor sensitive component 10 provided by the embodiment of the present application realizes the change of the comb gap by arranging the first comb tooth part 130 connected with the elastic beam 110 and the second comb tooth part 160 connected with the electrothermal driving beam 140, so that the comb gap is reduced to hundreds of nanometers or even tens of nanometers, the sensitivity of the comb capacitor to the external acceleration is improved by 2-3 orders of magnitude, and the acceleration of 10 -6 -10 -8 gravity can be sensed, the sensitivity of the acceleration sensor is improved, the zero offset of the acceleration sensor sensitive component 10 can be calibrated by adjusting the driving voltage of the electrothermal driving beam 140, and in addition, the structure is compact, the cost is low, the manufacturing process is simple, and the processing technology requirement is low.

[0042] Referring to the accompanying drawings, Figure 1 In the embodiment of the present application, the number of the elastic beams 110 is two and oppositely arranged, and the two ends of the frame 120 are respectively fixed to the two elastic beams 110. In this way, the rebound pressure can be guaranteed, and the stability of the position of the frame 120 can be maintained.

[0043] In the embodiment of the present application, the frame 120 is a mouth-shaped structure or an I-shaped structure, the frame 120 includes a first connecting plate 121, a second connecting plate 122, and a support frame 123 fixed between the two, one of the elastic beams 110 is fixed to the first connecting plate 121, the other elastic beam 110 is fixed to the second connecting plate 122, and a plurality of first sub-comb teeth 131 are fixedly arranged on the support frame 123.

[0044] Referring to the accompanying drawings, Figure 1 In the embodiment of the present application, the support frame 123 is fixedly provided with a first comb tooth mounting plate 124, and a plurality of first sub-comb teeth 131 are fixedly arranged on the first comb tooth mounting plate 124.

[0045] Referring to the accompanying drawings, Figure 1 In the embodiment of the present application, the number of the electrothermal driving beams 140 is two and oppositely arranged, and the two ends of the support 150 are respectively fixed to the two electrothermal driving beams 140.

[0046] Referring to the accompanying drawings, Figure 1 , Figure 2 , Figure 3 and Figure 4 In the embodiment of the present application, the cross-sectional shape of the electrothermal driving beam 140 is at least one of a V-shaped, N-shaped and A-shaped. In this way, the electrothermal driving beam 140 has high structural stability and strong driving force.

[0047] In the embodiment of the present application, the electrothermal driving beam 140 includes a plurality of groups of electrothermal sub-driving beams arranged in parallel. In this way, the electrothermal driving beam 140 has high structural stability and strong driving force, and is suitable for comb driving of high-precision acceleration sensing.

[0048] With reference to the accompanying drawings Figure 5 The acceleration sensor chip structure provided by the embodiment of the application comprises a shell 1 and the acceleration sensor sensitive assembly 10 described above, the acceleration sensor sensitive assembly is arranged in the shell 1, and a temperature control assembly and a controller 30 are further arranged in the shell 1, the temperature control assembly comprises a temperature sensor 21 and a temperature control component, the temperature sensor 21 and the temperature control component are electrically connected with the controller 30, the temperature sensor 21 is used for detecting a temperature value in the shell 1, and the controller 30 is used for receiving the temperature value and controlling the temperature control component to make the temperature value in a preset temperature range.

[0049] It should be noted that the acceleration sensor sensitive assembly can obtain the best precision in the preset temperature range, if the temperature is greater than the preset temperature range, the quality of a sensing signal will be reduced due to the increase of noise, and if the temperature is less than the preset temperature range, the sensitivity of the sensor will be reduced.

[0050] It should be noted that the acceleration sensor chip structure can have temperature drift, if the temperature drift occurs, the temperature is adjusted to the preset temperature range when the acceleration sensor chip structure is in a static state, the output value of the acceleration sensor at this time is detected, and the value is taken as the temperature drift at the current temperature, in the working process of the acceleration sensor, the output value of the acceleration sensor is subtracted by the temperature drift value of the preset temperature range, so that the temperature drift calibration of the acceleration sensor chip structure is realized.

[0051] Therefore, the acceleration sensor chip structure provided by the embodiment of the application can control the temperature in the shell 1 in the preset temperature range by arranging the temperature sensor 21 and the temperature control component which are electrically connected with the controller 30, and the sensitivity of the acceleration sensor sensitive assembly 10 is ensured, the temperature drift calibration of the acceleration sensor chip structure is realized, in addition, the acceleration sensor sensitive assembly 10 is arranged to be connected with the first comb tooth part 130 and the second comb tooth part 160 which are connected with the elastic beam 110 and the electrothermal driving beam 140 respectively, the change of the comb tooth gap is realized, the comb tooth gap is reduced to hundreds of nanometers or even tens of nanometers, the sensitivity of the comb tooth capacitor to the external acceleration is improved by 2-3 orders of magnitude, and the sensing of 10 -6 -10 -8 gravity acceleration is realized, and the sensitivity of the acceleration sensor is improved, the zero offset calibration of the acceleration sensor sensitive assembly 10 can be realized by adjusting the driving voltage of the electrothermal driving beam 140, the structure design is compact, the cost is low, the manufacturing process is simple, and the processing technology requirement is low.

[0052] In the embodiment of the application, the temperature control component comprises a heating component, which is used for increasing the temperature in the shell 1.

[0053] It should be noted that if the temperature sensor 21 detects that the temperature in the shell 1 is less than the preset temperature range, the controller controls the heating component to work, so that the temperature in the shell 1 is increased to the preset temperature range; if the temperature sensor 21 detects that the temperature in the shell 1 is greater than the preset temperature range, the heating component does not work.

[0054] Referring to the accompanying drawings Figure 5 In the embodiment of the present application, the shell 1 is further provided with a capacitor readout circuit assembly 40, which is used to convert the capacitance value of the acceleration sensor sensitive assembly 10 into a voltage value, and the voltage value can be an analog quantity or a digital quantity.

[0055] In the embodiment of the present application, the controller 30 is installed on the substrate 100.

[0056] In the embodiment of the present application, the temperature sensor 21 is installed on the substrate 100.

[0057] In the embodiment of the present application, the heating component is installed on the substrate 100.

[0058] In the embodiment of the present application, the capacitor readout circuit assembly 40 is installed on the substrate 100.

[0059] In the embodiment of the present application, the temperature sensor 21 is installed on the acceleration sensor sensitive assembly 10.

[0060] In the embodiment of the present application, the shell 1 is made of plastic, ceramic or metal.

[0061] In the embodiment of the present application, the substrate 100 is an organic substrate, a ceramic substrate or a metal substrate.

[0062] In the embodiment of the present application, the shell 1 is further provided with a resistance-capacitance device 50, which is necessary for the power supply, signal processing, signal output and protection circuit of the acceleration sensor chip.

[0063] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. An accelerometer sensing component, characterized in that, include: substrate(100); An elastic beam (110) is mounted on the substrate (100) and fixedly connected to a frame (120). The frame (120) is provided with a first comb tooth portion (130). The first comb tooth portion (130) includes a plurality of spaced first sub-comb teeth (131). A comb tooth groove (132) is formed between any adjacent first sub-comb teeth (131). There are two elastic beams (110) arranged opposite to each other. The two ends of the frame (120) are respectively fixedly connected to the two elastic beams (110). An electric heating drive beam (140) is mounted on the substrate (100) and located within the frame (120). The electric heating drive beam (140) is fixedly connected to a bracket (150). The bracket (150) is provided with a second comb tooth portion (160). The second comb tooth portion (160) includes a plurality of spaced second sub-comb teeth (161). The second sub-comb teeth (161) are respectively located in the comb tooth groove (132). The number of the electric heating drive beams (140) is two and they are arranged opposite each other. The two ends of the bracket (150) are respectively fixed to the two electric heating drive beams (140); and / or, the cross-sectional shape of the electric heating drive beams (140) is at least one of V-shaped, N-shaped and A-shaped; and / or, the electric heating drive beams (140) include multiple sets of electric heating sub-drive beams arranged in parallel.

2. The acceleration sensor sensing component according to claim 1, characterized in that, The frame (120) is a U-shaped structure or an I-shaped structure. The frame (120) includes a first connecting plate (121), a second connecting plate (122), and a support frame (123) fixed between the two. One of the elastic beams (110) is fixed to the first connecting plate (121); the other elastic beam (110) is fixed to the second connecting plate (122); and a plurality of first sub-comb teeth (131) are fixed to the support frame (123).

3. The acceleration sensor sensing component according to claim 2, characterized in that, The support frame (123) is fixedly provided with a first comb tooth mounting plate (124), and a plurality of first sub-comb teeth (131) are fixedly provided on the first comb tooth mounting plate (124).

4. An accelerometer chip structure, characterized in that, The device includes a housing (1) and an acceleration sensor sensing component (10) as described in any one of claims 1-3. The acceleration sensor sensing component is disposed within the housing (1). The housing (1) also includes a temperature control component and a controller (30). The temperature control component includes a temperature sensor (21) and a temperature control element. Both the temperature sensor (21) and the temperature control element are electrically connected to the controller (30). The temperature sensor (21) is used to detect the temperature value inside the housing (1). The controller (30) is used to receive the temperature value and control the temperature control element to keep the temperature value within a preset temperature range.

5. The accelerometer chip structure according to claim 4, characterized in that, The temperature control component includes a heating component for raising the temperature inside the housing (1).

6. The accelerometer chip structure according to claim 5, characterized in that, The housing (1) is also provided with a capacitor readout circuit assembly (40) for converting the capacitance value of the acceleration sensor sensing component (10) into a voltage value.

7. The accelerometer chip structure according to claim 6, characterized in that, The controller (30) is mounted on the base plate (100); And / or, the temperature sensor (21) is mounted on the substrate (100); And / or, the heating element is mounted on the substrate (100); And / or, the capacitor readout circuit assembly (40) is mounted on the substrate (100).

8. The accelerometer chip structure according to claim 7, characterized in that, The temperature sensor (21) is mounted on the acceleration sensor sensing component (10).

Images