A MEMS strain measurement device under temperature shock

Abstract

The present invention relates to the field of strain measurement technology, and provides a MEMS strain measurement device under temperature shock, comprising a shock-absorbing bracket, a compensation module, a first measuring resistor, a second measuring resistor, a MEMS substrate to be measured, an automatic weight-balancing device, a temperature box and a measuring strain rosette; the shock-absorbing bracket comprises a substrate, the measuring strain rosette is bonded to the MEMS substrate to be measured by layered heat-insulating bonding and ultrasonic treatment, and is sequentially connected with the compensation module, the first measuring resistor and the measuring resistor to form a ring; after the MEMS substrate to be measured, the compensation module, the first measuring resistor and the second measuring resistor are arranged on the substrate, the substrate is extended into the temperature box, and the assembly stress compensation module, the adhesive stress compensation module and the substrate bending stress compensation module are sequentially connected to form a compensation module; the automatic weight-balancing device comprises a control motor and a weight-balancing slider, and the weight-balancing slider is pushed and pulled by the control motor. The present invention can effectively measure the strain of MEMS devices.

Description

Technical Field

[0001] The present invention relates to the technical field of strain measurement, and in particular to a MEMS strain measurement device under temperature shock. Background Art

[0002] Electronic components in MEMS, especially gyroscopes and accelerometers, are extremely sensitive to temperature. Stress and strain changes caused by temperature can cause the data of MEMS gyroscopes and accelerometers to drift. Therefore, MEMS-based inertial navigation systems require system compensation for temperature. In addition, this also places stringent requirements on the installation method, bonding method, and shell strength of MEMS devices.

[0003] At present, there are few research results on thermal shock caused by temperature, internal stress of adhesive, bending stress of flexible board, assembly stress of fixed shell and their mutual coupling, which are difficult to guide production practice. In addition, the measurement standards, methods and mature equipment for micro deformation and stress of MEMS are still in the research stage and are not mature. Among them, the PCB (Printed Circuit Board) substrate is the carrier of MEMS, and its stress change under temperature shock has an important influence on the system accuracy of micro-inertial measurement MEMS. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a MEMS strain measurement device under temperature shock to achieve measurement of micro deformation of MEMS under temperature.

[0005] The present invention provides a MEMS strain measurement device under temperature shock, comprising a shock absorbing bracket, a compensation module, a first measuring resistor, a second measuring resistor, a MEMS substrate to be measured, an automatic weight balancing device, a temperature box and a measuring strain rosette; wherein the shock absorbing bracket comprises a substrate, the measuring strain rosette is bonded to the MEMS substrate to be measured by layered heat-insulating bonding and ultrasonic treatment, and is sequentially connected with the compensation module, the first measuring resistor and the second measuring resistor to form a ring, after the MEMS substrate to be measured, the compensation module, the first measuring resistor and the second measuring resistor are arranged on the substrate, the substrate is extended into the temperature box, and the temperature box provides a variable temperature environment for the MEMS substrate to be measured and the compensation module;

[0006] The compensation module comprises an assembly stress compensation module, an adhesive stress compensation module and a base bending stress compensation module, and the assembly stress compensation module, the adhesive stress compensation module and the base bending stress compensation module are sequentially connected to form the compensation module;

[0007] The shock-absorbing bracket also includes a cantilever, and the automatic weight-balancing device includes a control motor and a weight-balancing slider. The automatic weight-balancing device is installed at the end of the cantilever, and the control motor pushes and pulls the weight-balancing slider.

[0008] According to a MEMS strain measurement device under temperature shock provided by the present invention, the substrate comprises a fixed shell, a flexible plate is clamped in the MEMS substrate to be measured, and the MEMS substrate to be measured is fixed on the substrate through the fixed shell.

[0009] According to a MEMS strain measurement device under temperature shock provided by the present invention, the step of forming the layered thermal insulation bonding comprises:

[0010] Placing the measuring strain rosette on the MEMS substrate to be measured, and dripping adhesive on the measuring strain rosette to obtain a first adhesive layer;

[0011] Determining a heat preservation temperature and a heat preservation time, heating the first adhesive layer and maintaining it at the heat preservation temperature until the heat preservation time is reached;

[0012] Dropping a second layer of adhesive on the first adhesive layer to obtain a second adhesive layer;

[0013] The second adhesive layer is heated and maintained at the insulation temperature until the insulation time is reached.

[0014] According to a MEMS strain measurement device under temperature shock provided by the present invention, the ultrasonic treatment is to perform ultrasonic shock on the first adhesive layer and the second adhesive layer respectively through an ultrasonic probe.

[0015] According to a MEMS strain measurement device under temperature shock provided by the present invention, the assembly stress compensation module includes an assembly stress compensation substrate and an assembly stress compensation strain rosette provided with a backing adhesive, the assembly stress compensation strain rosette is fixed to the assembly stress compensation substrate by the backing adhesive, and the assembly stress compensation substrate is fixed to the substrate by the fixed shell.

[0016] According to a MEMS strain measurement device under temperature shock provided by the present invention,

[0017] The adhesive stress compensation module includes an adhesive stress compensation base and an adhesive stress compensation strain rosette, the adhesive stress compensation strain rosette is bonded to the adhesive stress compensation base through the layered thermal insulation bonding and the ultrasonic treatment, and the adhesive stress compensation base is placed on the substrate.

[0018] According to a MEMS strain measurement device under temperature shock provided by the present invention, the substrate bending stress compensation module includes a substrate bending stress compensation substrate and a substrate bending stress compensation strain rosette provided with a backing adhesive, a flexible board is sandwiched in the substrate bending stress compensation substrate, the substrate bending stress compensation strain rosette is fixed on the substrate bending stress compensation substrate by the backing adhesive, and the substrate bending stress compensation substrate is placed on the substrate.

[0019] According to a MEMS strain measurement device under temperature shock provided by the present invention, the control motor includes an electric push rod, and the electric push rod is connected to the counterweight slider. The control motor pushes and pulls the counterweight slider by driving the electric push rod. When the position of the counterweight slider changes, the resonant frequency of the shock-absorbing bracket changes.

[0020] According to a MEMS strain measurement device under temperature shock provided by the present invention, the bottom of the shock absorbing bracket is provided with a rubber shock absorbing pad.

[0021] According to a MEMS strain measurement device under temperature shock provided by the present invention, the inner wall of the temperature box is covered with aluminum foil.

[0022] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0023] The present invention provides a MEMS strain measurement device under temperature shock, which effectively compensates for assembly stress, adhesive stress and substrate bending stress through an assembly stress compensation module, an adhesive stress compensation module and a substrate bending stress compensation module; and the device also effectively avoids the influence of resonance on strain measurement through a movable counterweight slider. The device can effectively compensate for the error of strain measurement caused by environmental vibration and glue sticking, flexible board bending and fixed shell deformation. Finally, through a temperature shock test, the micro deformation of MEMS on the substrate under temperature shock is quantitatively measured.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1It is a structural schematic diagram of a MEMS strain measurement device under temperature shock provided by the present invention.

[0027] Figure 2 The present invention is a schematic diagram of the arrangement of a compensation module, a first measuring resistor, a second measuring resistor, and a MEMS substrate to be measured on a substrate of a MEMS strain measuring device under temperature shock provided by the present invention.

[0028] Figure 3 The present invention provides a schematic diagram of the principle of a Wheatstone bridge of a MEMS strain measurement device under temperature shock.

[0029] Reference numerals:

[0030] 1. Automatic counterweight device; 11. Control motor; 12. Counterweight slider; 13. Electric push rod; 2. Cantilever; 3. Base plate; 31. Fixed shell; 4. MEMS substrate to be measured; 41. Measuring strain rosette; 5. Compensation module; 51. Assembly stress compensation substrate; 52. Adhesive stress compensation substrate; 53. Substrate bending stress compensation substrate; 54. DC power supply; 6. First measuring resistor; 7. Second measuring resistor; 8. Temperature box; 9. Rubber shock pad; 10. Support rod; 101. Fixed base. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0032] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0033] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0034] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0036] Combine the following Figures 1 to 3 The present invention describes a MEMS (Micro-Electro-Mechanical System) strain measurement device under temperature shock. Figure 1 It is a structural schematic diagram of a MEMS strain measurement device under temperature shock, wherein the shock-absorbing bracket includes a cantilever 2, a substrate 3, a support rod 10, a rubber shock-absorbing pad 9 and a fixed base 101. The cantilever 2 is installed through the support rod 10, and the support rod 10 is fixed on the fixed base 101. The substrate 3 is fixed to one end of the cantilever 2 and extends into the temperature box 8. The lower part of the fixed base 101 is equipped with a rubber shock-absorbing pad 9, which can effectively isolate vibrations from the ground and the surrounding environment. The fixed base 101 has a large mass, can also effectively eliminate vibrations and can ensure the stability of the support rod 10 and the cantilever 2.

[0037] The other end of the cantilever 2 is provided with an automatic counterweight device 1, which includes a control motor 11 and an electric push rod 13 fixed at the other end of the cantilever, and also includes a counterweight slider 12 that can slide on the cantilever 2. The electric push rod 13 is connected to the counterweight slider 12, and the control motor 11 can control the position of the counterweight slider 12 on the cantilever 2 by driving the electric push rod 13 to extend and retract. In addition, a vibration sensor is also provided on the substrate 3, and the vibration sensor is connected to the control motor 11 through a wire.

[0038] Here, since the compressor and the hot air blower inside the temperature box 8 will generate vibration when the temperature box 8 is working, the substrate 3 inside the temperature box 8 will also vibrate. When the vibration frequency of the substrate 3 is the same as the resonance frequency of the shock-absorbing bracket, resonance will occur on the substrate 3, resulting in a significant increase in the vibration intensity on the substrate 3, affecting the accuracy of strain measurement. The vibration sensor can measure the vibration intensity on the substrate 3 and transmit it back to the control motor 11. When the vibration intensity exceeds the threshold value set in the control motor 11, it indicates that the substrate 3 has resonated. At this time, the control motor 11 drives the electric push rod 13 to push and pull the counterweight slider 12. When the counterweight slider 12 moves, the mass distribution inside the shock-absorbing bracket changes, so the resonance frequency of the shock-absorbing bracket will also change, so that the substrate 3 will no longer continue to resonate. At this time, the vibration intensity is reduced to below the threshold value set in the control motor 11, and the control motor 11 stops working until the vibration intensity exceeds the threshold value set in the control motor 11 again.

[0039] A fixed housing 31, a first measuring resistor 6 and a second measuring resistor 7 are also provided on the substrate 3. Here, the resistance values ​​of the first measuring resistor 6 and the second measuring resistor 7 are equal, and both are set to 100Ω. The fixed housing 31 includes a fixing bolt and a fixing bolt opening. The MEMS substrate 4 to be tested and the assembly stress compensation substrate 51 are provided with bolt openings corresponding to the positions of the fixing bolt openings. When the MEMS substrate 4 to be tested and the assembly stress compensation substrate 51 are installed in their respective fixed housings 31, the positions of the bolt openings are first aligned with the positions of the fixing bolt openings, and then the fixing bolts are screwed into the fixing bolt openings through the bolt openings to install the MEMS substrate 4 to be tested and the assembly stress compensation substrate 51 in their respective fixed housings 31. During installation, if the fixing bolts are tightened too much, the MEMS substrate 4 to be tested and the assembly stress compensation substrate 51 will be subjected to additional stress from the fixing bolts, and the magnitude of this additional stress cannot be guaranteed to be the same. If they are tightened too loosely, the fixing will not be in place. Therefore, here, a torque wrench is used when screwing in the fixing bolts. The torque wrench can make the fixing bolts be screwed in with the same torque, so that the tightness of the fixing bolts of the MEMS substrate 4 to be tested and the assembly stress compensation substrate 51 is moderate and the additional stress from the fixing bolts on the MEMS substrate 4 to be tested and the assembly stress compensation substrate 51 is the same and relatively reasonable, thereby ensuring the compensation effect of the assembly stress compensation module.

[0040] A MEMS device is mounted on the MEMS substrate 4 to be tested, and a flexible board, i.e., a flexible circuit board, is sandwiched in the middle of the substrate. The measuring strain flower 41 is glued to the back of the MEMS substrate 4 to be tested, and the gluing position is in the middle of the back of the area where the MEMS device is located. When gluing the strain flower, it is glued by layered thermal insulation bonding, and the use of glue can ensure a high measurement accuracy. Specifically, the insulation temperature and insulation time are first determined. In this embodiment, the insulation temperature is 60°C and the insulation time is 2 hours. Then, part of the strain flower special glue is evenly dripped on the measuring strain flower 41 to obtain the first adhesive layer. The first adhesive layer is heated to the insulation temperature and maintained at the insulation temperature until the insulation time is reached. The first adhesive layer is then subjected to ultrasonic treatment, that is, the first adhesive layer is subjected to uniform ultrasonic impact by an ultrasonic probe. Heating and heat preservation can make the stress distribution inside the adhesive layer more uniform, and avoid the uneven stress inside the adhesive layer affecting the measurement results of the strain gauge, while ultrasonic treatment can reorganize the microstructure inside the adhesive layer, and also make the stress distribution inside the adhesive layer more uniform. Then, the second layer of adhesive specifically for strain gauges is evenly dripped on the first adhesive layer to obtain a second adhesive layer, and then the second adhesive layer is heated to the insulation temperature and maintained at the insulation temperature until the insulation time is reached. Finally, the second adhesive layer is ultrasonically treated to complete the fixation of the measuring strain gauge 41. Layered laying of adhesive can avoid local stress concentration, cavitation and gaps caused by uneven solidification inside the adhesive after solidification due to excessive adhesive, thereby further improving the measurement accuracy of the measuring strain gauge 41. Finally, the MEMS substrate 4 to be measured is installed in the fixed housing 31, so that the MEMS substrate 4 to be measured is installed on the substrate 3.

[0041] The assembly stress compensation module includes an assembly stress compensation substrate 51 and an assembly stress compensation strain rosette with adhesive backing. The substrate shape and material of the assembly stress compensation substrate 51 are the same as those of the MEMS substrate 4 to be tested, but there is no flexible board in the middle and no MEMS device is installed on the assembly stress compensation substrate 51. The assembly stress compensation strain rosette is pasted on the assembly stress compensation substrate 51 at the same position as the measurement strain rosette 41 on the MEMS substrate 4 to be tested by using adhesive backing, and the stress generated by the adhesive backing is almost negligible. Then, the assembly stress compensation substrate 51 is installed in the fixed housing 31 to install the assembly stress compensation module on the substrate 3, so that the assembly stress of the assembly stress compensation strain rosette, that is, the additional stress caused by the deformation and extrusion of the fixed housing 31 and the additional stress from the fixing bolts, is the same as the assembly stress of the measurement strain rosette 41 on the MEMS substrate 4 to be tested, so that the resistance change of the assembly stress compensation strain rosette caused by the strain generated by the assembly stress is the same as the resistance change of the measurement strain rosette 41 caused by the strain generated by the assembly stress.

[0042] The adhesive stress compensation module includes an adhesive stress compensation substrate 52 and an adhesive stress compensation strain rosette. The substrate shape and material of the adhesive stress compensation substrate 52 are the same as those of the MEMS substrate 4 to be tested, but there is no flexible board in the middle and no MEMS device is installed on the adhesive stress compensation substrate 52. The adhesive stress compensation strain rosette is bonded to the same position on the adhesive stress compensation substrate 52 as the measuring strain rosette 41 on the MEMS substrate 4 to be tested by using a special adhesive for strain rosettes and through layered heat-insulating bonding and ultrasonic treatment, and then the adhesive stress compensation substrate 52 is placed on the substrate 3, so that the stress from the adhesive on the adhesive stress compensation strain rosette is the same as the stress from the adhesive on the measuring strain rosette 41 on the MEMS substrate 4 to be tested, so that the resistance change of the adhesive stress compensation strain rosette caused by the strain generated by the stress from the adhesive is the same as the resistance change of the measuring strain rosette 41 caused by the strain generated by the stress from the adhesive.

[0043] The substrate bending stress compensation module includes a substrate bending stress compensation substrate 53 and a substrate bending stress compensation strain rosette with adhesive backing. The substrate shape and material of the substrate bending stress compensation substrate 53 are the same as those of the MEMS substrate 4 to be tested, and a flexible board is sandwiched in the middle of the substrate, but no MEMS device is installed on the substrate bending stress compensation substrate 53. The substrate bending stress compensation strain rosette is glued to the same position of the substrate bending stress compensation substrate 53 as the measuring strain rosette 41 on the MEMS substrate 4 to be tested by using adhesive backing, and then the substrate bending stress compensation substrate 53 is placed on the substrate 3, so that the substrate bending stress caused by the flexible board sandwiched on the substrate bending stress compensation strain rosette is the same as the substrate bending stress caused by the flexible board sandwiched on the measuring strain rosette 41 on the MEMS substrate 4 to be tested, so that the resistance change caused by the strain generated by the substrate bending stress of the substrate bending stress compensation strain rosette is the same as the resistance change caused by the strain generated by the substrate bending stress of the measuring strain rosette 41. Here, the substrate bending stress is generated due to the deformation of the flexible board.

[0044] The compensation module 5 can be formed by sequentially connecting the assembly stress compensation strain rosette of the assembly stress compensation module, the adhesive stress compensation strain rosette of the adhesive stress compensation module and the base bending stress compensation strain rosette of the base bending stress compensation module. In an optional embodiment, only 1-2 modules can be selected for connection according to actual needs to form the compensation module 5.

[0045] Figure 2The figure is a schematic diagram of the arrangement of the compensation module 5, the first measuring resistor 6, the second measuring resistor 7, and the MEMS substrate 4 to be tested on the substrate. After the MEMS substrate 4 to be tested, the assembly stress compensation module, the adhesive stress compensation module, and the substrate bending stress compensation module are arranged on the substrate 3, the connection work can be started. Here, the strain rosettes of each compensation module, the measuring strain rosette 41, the first measuring resistor 6, and the second measuring resistor 7 on the substrate 3 are connected. The measuring strain rosette 41, the first measuring resistor 6, the second measuring resistor 7, and the compensation module 5 on the MEMS substrate 4 to be tested are connected in sequence to form a ring, and one end of a DC power supply 54 with a voltage of 5V is connected to one end of the measuring strain rosette 41 on the MEMS substrate 4 to be tested and one end of the first measuring resistor 6, and the other end of the DC power supply 54 is connected to one end of the compensation module 5 and one end of the second measuring resistor 7 to form a Wheatstone bridge for measurement.

[0046] Figure 3 It is a schematic diagram of the principle of the Wheatstone bridge. According to the characteristics of the Wheatstone bridge, under the condition that the resistance values ​​of the first measuring resistor 6 and the second measuring resistor 7 are equal, when the ratio of the resistance of the measuring strain flower 41 of the MEMS substrate 4 to be tested to the first measuring resistor 6 is equal to the ratio of the resistance of all the strain flowerets in the compensation module 5 to the second measuring resistor 7, that is, the resistance generated by the strain generated by the assembly stress, adhesive stress and substrate bending stress of the measuring strain flower 41 is equal to the resistance generated by the strain of all the strain flowerets in the compensation module 5, then one end of the precision voltmeter is connected to the other end of the measuring strain flower 41 on the MEMS substrate 4 to be tested and the other end of the compensation module 5, and the other end of the precision voltmeter is connected to the other end of the first measuring resistor 6 and the other end of the second measuring resistor 7, then the reading of the voltmeter should be 0 in theory. However, since a MEMS device is also installed on the MEMS substrate 4 to be tested, the packaging of the MEMS device, solder, etc. will also generate stress, which is exactly what the present application needs to measure. In this embodiment, according to the existing data, when the interference of assembly stress, adhesive stress and substrate bending stress is effectively compensated, the voltage reading of the strain gauge is 5.17 mV at room temperature, i.e., 25°C. Therefore, when the reading of the precision voltmeter is 5.17 mV, it can be considered that the resistance of the strain gauge 41 due to strain is equal to the resistance of all the strain gauges in the compensation module 5 due to strain, and the assembly stress, adhesive stress and substrate bending stress are effectively compensated.

[0047] After the connection is completed, the voltage is monitored by a precision voltmeter. At this time, since the assembly stress, adhesive stress and substrate bending stress are all compensated, and the temperature environment, substrate material, shape, etc. of the compensation module 5 and the MEMS substrate 4 to be measured are the same, the change in voltage at this time, that is, the change in the precision voltmeter reading caused by the change in the resistance of the strain gauge 41, is due to the strain caused by the temperature change of the MEMS device and its packaging, solder, etc. on the MEMS substrate 4 to be measured. Insulation cotton is filled between the opening of the temperature box 8 and the cantilever 2 to ensure the insulation effect. In addition, the insulation cotton can also reduce the deformation stress of the connecting line between the inside and outside of the temperature box 8 to ensure the measurement effect. In the present invention, since the compressor, hot air blower and control motor 11 inside the temperature box 8 will generate electromagnetic radiation, which may interfere with the measurement result of the strain gauge 41, and may also affect the compensation effect of the compensation module 5, it is necessary to cover the inner wall of the temperature box 8 with aluminum foil, so as to effectively shield the electromagnetic radiation of the compressor, hot air blower and control motor 11 inside the temperature box 8 and ensure the measurement accuracy.

[0048] Then the temperature box 8 is cooled or heated so that the temperature inside the temperature box 8 reaches the set temperature. In this embodiment, the temperature range is -40°C~60°C, and several reasonable temperature values ​​are taken within this range for measurement. When each temperature value is reached, it is kept at this temperature value for 20 minutes to ensure that the temperature inside the temperature box 8 is uniform, and then the reading of the precision voltmeter at this time is read. The strain occurring at the strain flower 41 at this time can be obtained through the reading of the precision voltmeter, and then the stress here can be obtained through the strain. It should be noted that the relationship between strain and stress is nonlinear but known. In this embodiment, the material of the substrate is a printed circuit board.

[0049] The present invention verifies the effectiveness of a MEMS strain measurement device under temperature shock, and conducts a temperature shock test on the MEMS substrate 4 to be tested in the range of -40°C to 60°C. Here, the strain and voltmeter readings at room temperature of 25°C are used as the starting point of the experiment. It should be noted that the stress change value and strain change value in the experimental data are not absolute values, but are relative to the strain and stress in the data in the previous row of the table, that is, the change value relative to the corresponding data in the previous row. For example, when the temperature drops to -40°C, the strain change value and stress change value are the difference between the strain at this time and the strain at 25°C and the difference between the stress at this time and the stress at 25°C, respectively; for another example, when the temperature increases from 30°C to 40°C, since the reading of the precision voltmeter does not change, it means that no strain occurs in the process from 30°C to 40°C, so the stress change value and the strain change value are both 0. Table 1 is a schematic table of the results of the temperature shock test:

[0050] Table 1 Schematic table of the results of temperature shock test

[0051]

[0052] in, Microstrain is the unit used to express strain.

[0053] From the experimental results, it can be seen that MEMS devices have a temperature operating range, that is, -20℃ to 50℃. When the temperature is lower than -20℃, MEMS devices will produce more than 80 The strain change value is greater than 1.48MPa. When the temperature is higher than 50℃, a stress change greater than 35 The strain change value is close to 0.53MPa. Here, because the MEMS device needs to use materials such as solder during the packaging process, and these materials will soften under high temperature conditions, the MEMS device has a lower tolerance for stress and strain in a high temperature environment. This shows that when the temperature is lower than -20°C or higher than 50°C, the stress change and strain change of MEMS will increase significantly, and the present invention can effectively measure the tiny deformation of MEMS on the substrate under temperature shock.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A MEMS strain measurement device under temperature shock, characterized in that: The device comprises a shock-absorbing bracket, a compensation module, a first measuring resistor, a second measuring resistor, a MEMS substrate to be measured, an automatic weight balancing device, a temperature box and a measuring strain rosette; wherein the shock-absorbing bracket comprises a substrate, the measuring strain rosette is bonded to the MEMS substrate to be measured by layered heat-insulating bonding and ultrasonic treatment, and is sequentially connected with the compensation module, the first measuring resistor and the second measuring resistor to form a ring; after the MEMS substrate to be measured, the compensation module, the first measuring resistor and the second measuring resistor are arranged on the substrate, the substrate is extended into the temperature box, and the temperature box provides a variable temperature environment for the MEMS substrate to be measured and the compensation module; wherein the substrate comprises a fixed shell, a flexible board is clamped in the MEMS substrate to be measured, and the MEMS substrate to be measured is fixed on the substrate through the fixed shell; The compensation module includes an assembly stress compensation module, an adhesive stress compensation module and a base bending stress compensation module, and the assembly stress compensation module, the adhesive stress compensation module and the base bending stress compensation module are sequentially connected to form the compensation module; wherein the assembly stress compensation module includes an assembly stress compensation base and an assembly stress compensation strain rosette provided with adhesive backing, the assembly stress compensation strain rosette is fixed on the assembly stress compensation base through the adhesive backing, and the assembly stress compensation base is fixed on the substrate through the fixed shell; The adhesive stress compensation module comprises an adhesive stress compensation substrate and an adhesive stress compensation strain rosette, the adhesive stress compensation strain rosette is bonded to the adhesive stress compensation substrate through the layered thermal insulation bonding and the ultrasonic treatment, and the adhesive stress compensation substrate is placed on the substrate; The base bending stress compensation module comprises a base bending stress compensation base and a base bending stress compensation strain rosette provided with adhesive backing, wherein a flexible plate is sandwiched in the base bending stress compensation base, the base bending stress compensation strain rosette is fixed on the base bending stress compensation base through the adhesive backing, and the base bending stress compensation base is placed on the substrate; The shock-absorbing bracket also includes a cantilever, and the automatic weight-balancing device includes a control motor and a weight-balancing slider. The automatic weight-balancing device is installed at the end of the cantilever, and the control motor pushes and pulls the weight-balancing slider.

2. The MEMS strain measurement device under temperature shock according to claim 1, characterized in that: The forming steps of the layered thermal insulation bonding include: Placing the measuring strain rosette on the MEMS substrate to be measured, and dripping adhesive on the measuring strain rosette to obtain a first adhesive layer; Determining a heat preservation temperature and a heat preservation time, heating the first adhesive layer and maintaining it at the heat preservation temperature until the heat preservation time is reached; Dropping a second layer of adhesive on the first adhesive layer to obtain a second adhesive layer; The second adhesive layer is heated and maintained at the insulation temperature until the insulation time is reached.

3. The MEMS strain measurement device under temperature shock according to claim 2, characterized in that: The ultrasonic treatment is to perform ultrasonic impact on the first adhesive layer and the second adhesive layer respectively through an ultrasonic probe.

4. The MEMS strain measurement device under temperature shock according to claim 1, characterized in that: The control motor includes an electric push rod, which is connected to the counterweight slider. The control motor pushes and pulls the counterweight slider by driving the electric push rod. When the position of the counterweight slider changes, the resonance frequency of the shock-absorbing bracket changes.

5. The MEMS strain measurement device under temperature shock according to claim 1, characterized in that: The bottom of the shock-absorbing bracket is provided with a rubber shock-absorbing pad.

6. The MEMS strain measurement device under temperature shock according to claim 1, characterized in that: The inner wall of the temperature box is covered with aluminum foil.

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