Radial and tangential bridge resistance balancing method based on etching solution concentration and pressure sensor

Abstract

The invention relates to the technical field of sensors, and provides a radial and tangential bridge resistance balancing method based on etching liquid concentration and a pressure sensor, and the method comprises the steps: according to the first wiring radius of a radial sensitive grid and the second wiring radius of a tangential sensitive grid, calculating the first wiring radius of the radial sensitive grid and the second wiring radius of the tangential sensitive grid; the concentration of etching liquid, used for etching the radial sensitive grid and the tangential sensitive grid, of the pressure sensor is determined, and the first wiring radius and the second wiring radius have the corresponding relation with the concentration of the etching liquid. The resistance values of the tangential sensitive grid and the radial sensitive grid which are etched according to the determined etching liquid concentration tend to be consistent, so that the zero setting workload of the sensor is reduced, the etching yield of the sensitive grid is improved, and the problems that in the prior art, the zero setting workload is large, the yield is low, and the risk of damaging the structure of the sensitive grid exists are solved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a radial and tangential bridge resistance balancing method based on etching solution concentration and a pressure sensor. Background Art

[0002] MCS (Multi-metal Fusion System) is a pressure sensor made of elastomers, fusion materials, and sensitive materials through joint pressure technology. When the MCS sensor does not receive the applied pressure, the output of the sensor should be near the zero point. Therefore, in practical applications, it is necessary to adjust the sensitive gate resistance of the MCS pressure sensor, that is, the zeroing operation. When zeroing, if the resistance difference between multiple resistors is large, the resistance value that needs to be adjusted will also increase. In the prior art, the commonly used sensitive gate resistance adjustment methods mainly include physical friction, laser ablation, and electrochemical methods. Among them, during the laser ablation resistance adjustment process, the high temperature can easily damage the fusion material and deteriorate the insulation strength of the sensor; and the electrochemical method is complicated and costly to adjust the resistance process. Although physical friction adjustment of resistance can adjust the resistance value at a lower cost, it is impossible to adjust the resistance with a large resistance difference, and the physical friction method also has the risk of damaging the sensitive gate.

[0003] In summary, the zeroing method in the prior art has at least the following defects: the zeroing workload is large and the efficiency is low, there is a risk of damaging the sensitive gate structure, the adjustment range is limited and the yield is low. Summary of the invention

[0004] In response to the above problems, the first aspect of the present application provides an MCS pressure sensor and a radial and tangential bridge resistance balancing method based on etching solution concentration, which are used to solve the technical problems raised in the background technology part of the present application.

[0005] To achieve the purpose of this application, this application provides the following technical solutions:

[0006] In a first aspect, the present application provides a radial and tangential bridge resistance balancing method based on etching solution concentration, which is applied to a pressure sensor, wherein the sensitive gate of the pressure sensor includes a radial sensitive gate and a tangential sensitive gate, and the radial sensitive gate and the tangential sensitive gate are etched on the same plane, and the method includes:

[0007] Determine a first wiring radius of the radial sensitive grid and a second wiring radius of the tangential sensitive grid respectively according to processing requirements of the pressure sensor;

[0008] According to the determined first wiring radius and the second wiring radius, the concentration of the etching solution used to etch the radial sensitive gate and the tangential sensitive gate of the pressure sensor is determined, wherein the first wiring radius and the etching solution concentration have a first corresponding relationship, and the second wiring radius and the etching solution concentration have a second corresponding relationship, the etching solution concentration is determined in combination with the first corresponding relationship and the second corresponding relationship, and the sensitive gate of the pressure sensor is etched according to the etching solution concentration, and the difference between the radial sensitive gate resistance and the tangential sensitive gate resistance after etching is within a preset threshold.

[0009] Furthermore, in the first corresponding relationship, the value of the first wiring radius is negatively correlated with the concentration of the etching solution, and the larger the value of the first wiring radius is, the smaller the concentration of the etching solution is.

[0010] Furthermore, in the first corresponding relationship:

[0011] When the first wiring radius is between 3 and 7 mm, the etching solution concentration is between 13 and 15%;

[0012] When the first wiring radius is between 4 and 8 mm, the etching solution concentration is between 10 and 12%;

[0013] When the first wiring radius is between 5 and 9 mm, the etching solution concentration is between 7 and 9%;

[0014] When the first wiring radius is between 7 and 12 mm, the etching solution concentration is between 4 and 6%.

[0015] Furthermore, in the second corresponding relationship, the value of the second wiring radius is negatively correlated with the concentration of the etching solution, and the larger the value of the second wiring radius is, the smaller the concentration of the etching solution is.

[0016] Furthermore, in the second corresponding relationship,

[0017] When the second wiring radius is between 0.1 and 3 mm, the etching solution concentration is between 13 and 15%;

[0018] When the second wiring radius is between 0.1 and 4 mm, the etching solution concentration is between 10 and 12%;

[0019] When the second wiring radius is between 0.1 and 5 mm, the etching solution concentration is between 7 and 9%.

[0020] When the second wiring radius is between 0.1 and 7 mm, the etching solution concentration is between 4 and 6%.

[0021] Furthermore, the pressure sensor is an MCS pressure sensor.

[0022] Furthermore, the step of etching the sensitive gate of the pressure sensor according to the concentration of the etching solution further includes:

[0023] Acquire a first processing line width corresponding to the radial sensitive gate and a second processing line width corresponding to the tangential sensitive gate, wherein the first processing line width and the second processing line width have a second corresponding relationship, and the first processing line width is greater than the second processing line width;

[0024] Determine a preset threshold value of the difference between the radial sensitive gate resistance value and the tangential sensitive gate resistance value after etching according to the first wiring radius, the second wiring radius, the first processing line width, and the second processing line width;

[0025] The sensitive gate of the pressure sensor is etched according to the first processing line width, the second processing line width, and the etching solution concentration.

[0026] In the second aspect, the present application provides an MCS pressure sensor, which is prepared based on the above-mentioned radial and tangential bridge resistance balancing method based on etching solution concentration. The MCS pressure sensor includes a sensitive material layer, an elastomer layer and a fusion layer; the sensitive material layer includes a radial sensitive gate and a tangential sensitive gate, the radial sensitive gate and the tangential sensitive gate form a Wheatstone bridge structure, the radial sensitive gate and the tangential sensitive gate are coaxial and arranged in the same plane, the tangential sensitive gate is arranged at the axis, and the radial sensitive gate is arranged near the circumference; the end of the elastomer layer away from the sensitive material layer is processed with a blind hole structure, and the elastomer layer is used to receive stress; a fusion layer, the fusion layer is coated on the elastic layer, and is used for the joint pressure fusion of the sensitive material layer and the elastomer layer.

[0027] Through the radial and tangential bridge resistance balancing method based on etching solution concentration provided by the present application, the etching solution concentration is determined based on the corresponding relationship between the radial sensitive gate wiring radius, the tangential sensitive gate wiring radius and the etching solution concentration, and the pressure sensor is etched. According to the above corresponding relationship, the radial and tangential sensitive gate resistance values ​​of the pressure sensor after etching tend to be consistent. The present application achieves the technical effect of reducing the workload of sensor zeroing and improving the etching yield of the sensitive gate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application.

[0029] Figure 1 A schematic diagram of a radial and tangential bridge resistance balancing method based on etching solution concentration provided in an embodiment of the present application;

[0030] Reference numerals in the figure: 1, first radial sensitive grid; 2, second radial sensitive grid; 3, first tangential sensitive grid; 4, second tangential sensitive grid. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of this application, unless otherwise specified, "plurality" means two or more.

[0033] The present application provides a radial and tangential bridge resistance balancing method based on etching solution concentration, and determines the etching solution concentration based on the corresponding relationship between the radial sensitive gate wiring radius, the tangential sensitive gate wiring radius and the etching solution concentration, and etches the pressure sensor. According to the above corresponding relationship, the radial and tangential sensitive gate resistance values ​​of the pressure sensor after etching tend to be consistent. The present application achieves the technical effect of reducing the workload of sensor zeroing and improving the etching yield of the sensitive gate.

[0034] The radial and tangential bridge resistance balancing method based on etching solution concentration provided in this embodiment is used to prepare a pressure sensor based on MCS (Metals Coalesce System). MCS technology is to first fuse the elastomer and foil material together before processing the diameter and thickness of the elastomer strain diaphragm, and finally form the sensitive grid (strain gauge) of the Wheatstone bridge through etching. That is: first fuse the elastomer and strain gauge foil material and then process the elastomer and strain gauge structure. The MCS pressure sensor is an MCS pressure sensor with a precise sensitive grid structure. The sensitive grid is strained after being compressed, thereby generating an output signal.

[0035] A radial and tangential bridge resistance balancing method based on etching solution concentration provided in this embodiment is used to prepare the above-mentioned MCS pressure sensor, wherein the sensitive gate of the MCS pressure sensor includes a radial sensitive gate and a tangential sensitive gate, wherein the radial sensitive gate and the tangential sensitive gate are coaxially arranged and located in the same plane of the sensor, and the method provided in this embodiment satisfies a corresponding relationship between the wiring radius of the radial sensitive gate, the wiring radius of the tangential sensitive gate and the etching solution concentration, so that the difference between the resistance value of the radial sensitive gate and the resistance value of the tangential sensitive gate of the MCS pressure sensor after etching according to the etching solution concentration is within a preset threshold range, thereby reducing the workload of zero adjustment.

[0036] Specifically, according to Figure 1 As shown, the positional relationship between the radial sensitive gate and the tangential sensitive gate is shown in the figure. The MCS pressure sensor in this embodiment is preferably a pressure sensor including four sensitive gate structures, including two radial sensitive gate structures arranged along the circumference (a first radial sensitive gate 1 and a second radial sensitive gate 2), and two tangential sensitive gate structures arranged along the axis (a first tangential sensitive gate 3 and a second tangential sensitive gate 4), the radial sensitive gate is coaxially arranged with the tangential sensitive gate and is located in the sensitive material layer of the sensor. Among them, the tangential sensitive gate structure is mainly subjected to tangential strain, and the radial sensitive gate structure is mainly subjected to radial strain. When the pressure sensor is subjected to external force, the length or cross-sectional area of ​​the sensitive gate structure changes, thereby causing the resistance value output by the pressure sensor to change.

[0037] Furthermore, due to the shape characteristics of the sensitive grid, the radial strain resistor formed by the radial sensitive grid structure is arranged along the radial direction, and the radial strain resistor contacts a larger flow of etching liquid during the etching process; while the tangential strain resistor formed by the tangential sensitive grid structure is arranged along the circumferential direction, and the tangential strain resistor contacts a smaller flow. Therefore, the radial sensitive grid structure is corroded more seriously by the etching liquid, resulting in a reduction in the cross-sectional area of ​​the radial strain resistor. It can be seen from the following formula (1) that the resistance cross-sectional area of ​​the radial strain resistor increases, and the resistance cross-sectional area of ​​the tangential strain resistor decreases, resulting in the radial strain resistor value being greater than the tangential strain resistor value.

[0038]

[0039] In the above formula (1), R is the resistance value, ρ is the resistivity, l is the resistor length, and S is the resistor cross-sectional area.

[0040] According to formula (1), the tangential strain resistor is more likely to have sensitive gate adhesion due to the increase of the resistance cross-sectional area, and the radial strain resistor is more likely to have sensitive gate fracture due to the increase of the resistance cross-sectional area, and the adhesion and fracture of the sensitive gate reduce the yield rate. Therefore, according to the method provided by the present application, the wiring radius of the radial sensitive gate, the wiring radius of the tangential sensitive gate and the etching solution concentration satisfy the corresponding relationship, so that the resistance value of the radial sensitive gate of the MCS pressure sensor after etching according to the etching solution concentration and the resistance value difference of the tangential sensitive gate are within the preset threshold range, thereby reducing the workload of zeroing.

[0041] Furthermore, a first wiring radius of the radial sensitive gate and a second wiring radius of the tangential sensitive gate are respectively determined according to the processing requirements of the pressure sensor; and an etching solution concentration for etching the radial sensitive gate and the tangential sensitive gate of the pressure sensor is determined according to the determined first wiring radius and the second wiring radius, wherein the first wiring radius and the etching solution concentration have a first corresponding relationship, and the second wiring radius and the etching solution concentration have a second corresponding relationship, the etching solution concentration is determined in combination with the first corresponding relationship and the second corresponding relationship, and the sensitive gate of the pressure sensor is etched according to the etching solution concentration, and the difference between the resistance value of the radial sensitive gate and the resistance value of the tangential sensitive gate after etching is within a preset threshold.

[0042] Specifically, according to Figure 1 As shown, the first wiring radius is Figure 1 The radius difference between points R2 and R1 from the center of the circle is R1~R2; the second wiring radius is Figure 1 The radius difference between points R4 and R3 from the center of the circle is R3-R4. This embodiment adjusts the etching solution concentration according to the different sensitive materials so that the resistance difference between the radial sensitive grid and the tangential sensitive grid after etching of the MCS pressure sensor is within the preset threshold range, thereby reducing the workload of zero adjustment.

[0043] Furthermore, the values ​​of the first wiring radius and the second wiring radius are negatively correlated with the etching solution concentration. The etching solution concentration is adjusted according to the different sensitive materials so that the resistance value after etching can be close to the tangential strain resistance value. When the values ​​of the first wiring radius and the second wiring radius respectively satisfy the first corresponding relationship and the second corresponding relationship with the etching solution concentration, the difference between the resistance value of the radial sensitive grid of the pressure sensor after etching and the resistance value of the tangential sensitive grid is within a preset threshold range.

[0044] Preferably, the corresponding relationship between the etching solution concentration and the first wiring radius and the second wiring radius includes:

[0045] When the etching solution concentration is 13-15%, the first wiring radius R1-R2 is 3-7 mm, and the second wiring radius R3-R4 is 0.1-3 mm;

[0046] When the etching solution concentration is 10-12%, the first wiring radius R1-R2 is 4-8 mm, and the second wiring radius R3-R4 is 0.1-4 mm;

[0047] When the etching solution concentration is 7-9%, the first wiring radius R1-R2 is 5-9 mm, and the second wiring radius R3-R4 is 0.1-5 mm;

[0048] When the etching solution concentration is 4-6%, the first wiring radius R1-R2 is 7-12 mm, and the second wiring radius R3-R4 is 0.1-7 mm.

[0049] The present application also redesigns the first processing line width of the radial sensitive gate and the second processing line width of the tangential sensitive gate so that the radial sensitive gate line width and the tangential sensitive gate line width satisfy a specific corresponding relationship, and further makes the resistance value difference between the radial sensitive gate of the pressure sensor after etching and the resistance value of the tangential sensitive gate fall within a preset threshold range.

[0050] In this embodiment, the corresponding relationship between the first processing line width and the second processing line width satisfies: the first processing line width is greater than or equal to the second processing line width, and the difference between the first processing line width and the second processing line width is preferably between 0.2-5 μm.

[0051] Specifically, the corresponding relationship between the radial sensitive gate line width and the tangential sensitive gate line width is determined by simulation to reduce the difference in sensitive gate resistance caused by etching, and to ensure that the sensitive gate of the radial strain resistor is similar to the sensitive gate resistance of the tangential strain resistor. Before performing the simulation, it is necessary to select the sensitive gate material and the basic parameters of the sensitive gate according to the actual application. The selection of sensitive gate materials is mainly based on their elastic modulus, temperature resistance and moisture resistance. Commonly used sensitive gate materials include: Constantan, which has good temperature stability and low resistance temperature coefficient; iron-chromium-aluminum alloy, which has a higher elastic modulus and heat resistance; nickel-chromium-aluminum alloy, which has a higher elastic modulus and heat resistance. The basic parameters of the sensitive gate that need to be determined include: sensitive gate resistance, sensitive gate length, grid wire thickness, grid length and grid wire spacing.

[0052] The embodiment determines the following corresponding relationship through simulation: the first processing line width of the radial sensitive grid is greater than the second processing line width of the tangential sensitive grid, and the first processing line width and the second processing line width have a first corresponding relationship, and the first corresponding relationship is shown in the following formula (2):

[0053] y=kx+b (2)

[0054] In formula (2), y is the first processing line width of the radial sensitive grid, in microns; k is the line width coefficient; x is any point on a single radial length l1 of the radial sensitive grid; b is the line width of the tangential sensitive grid, in microns.

[0055] The difference (yb) between the first processing line width y and the second processing line width is positively correlated with the etching solution concentration, and the greater the etching solution concentration, the greater the difference. For example, the line width coefficient k and the first processing line width y include the following corresponding relationship:

[0056] When the etching solution concentration is 5%, take Radial strain sensitive gate line width

[0057] When the etching solution concentration is 15%, The radial strain sensitive grid line width y=b+2, that is, the radial strain line width is 2 microns wider than the tangential strain line width;

[0058] When the etching solution concentration is 30%, take The radial strain sensitive grid line width y=b+2+0.1x, that is, the radial strain line width is an isosceles trapezoid, and is wider away from the center of the circle;

[0059] When the etching solution concentration is 42%, k = x, and the radial strain sensitive gate line width y = b + x 2 .

[0060] Furthermore, in formula (2), the first processing line width y is positively correlated with the single radial length l1 of the radial sensitive grid.

[0061] The present application also provides an MCS pressure sensor, which is prepared according to the radial and tangential bridge resistance balancing method based on the etching solution concentration described above in the present application, and the MCS pressure sensor includes a sensitive material layer, an elastomer layer and a fusion layer; the sensitive material layer includes a radial sensitive gate and a tangential sensitive gate, the radial sensitive gate and the tangential sensitive gate constitute a Wheatstone bridge structure, the radial sensitive gate and the tangential sensitive gate are coaxial and arranged in the same plane, the tangential sensitive gate is arranged at the axis, and the radial sensitive gate is arranged near the circumference; a blind hole structure is processed at one end of the elastomer layer away from the sensitive material layer, and the elastomer layer is used to receive stress; a fusion layer, the fusion layer is coated on the elastic layer, and is used for the joint pressure fusion of the sensitive material layer and the elastomer layer.

[0062] The beneficial effects of the embodiments of the present application are as follows:

[0063] 1. The wiring radius of the radial sensitive gate and the tangential sensitive gate is adjusted based on the etching solution concentration, which further reduces the resistance difference between the radial and tangential sensitive gates caused by the corrosion of the radial sensitive gate and ensures the zeroing effect;

[0064] 2. By adjusting the line width of the radial sensitive gate and the tangential sensitive gate to form a specific pattern, the radial sensitive gate line width increases, so that the radial and tangential sensitive gate resistances of the MCS pressure sensor after etching tend to be consistent, thereby achieving the technical effect of reducing the workload of sensor zeroing and improving the etching yield of the sensitive gate.

[0065] In the several embodiments provided in the present application, it should be understood that the disclosed systems, modules and methods can be implemented in other ways. For example, the module embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, modules or units, which can be electrical, mechanical or other forms.

[0066] The above embodiments are only used to illustrate the technical solution of the present application, but not to limit it. The present application is not limited to the exact structure described above and illustrated in the accompanying drawings, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, various changes and modifications made without departing from the concept of the present application should be deemed to belong to the protection scope of the present application.

Claims

1. A radial and tangential bridge resistance balancing method based on etching solution concentration, characterized in that: The method is applied to a pressure sensor, wherein the sensitive grid of the pressure sensor includes a radial sensitive grid and a tangential sensitive grid, and the radial sensitive grid and the tangential sensitive grid are etched on the same plane. The method includes: Determine a first wiring radius of the radial sensitive grid and a second wiring radius of the tangential sensitive grid respectively according to processing requirements of the pressure sensor; According to the determined first wiring radius and the second wiring radius, the concentration of the etching solution used to etch the radial sensitive gate and the tangential sensitive gate of the pressure sensor is determined, wherein the first wiring radius and the etching solution concentration have a first corresponding relationship, and the second wiring radius and the etching solution concentration have a second corresponding relationship, the etching solution concentration is determined in combination with the first corresponding relationship and the second corresponding relationship, and the sensitive gate of the pressure sensor is etched according to the etching solution concentration, and the difference between the radial sensitive gate resistance and the tangential sensitive gate resistance after etching is within a preset threshold.

2. The method for balancing radial and tangential bridge resistance based on etching solution concentration according to claim 1, characterized in that: In the first corresponding relationship, the value of the first wiring radius is negatively correlated with the concentration of the etching solution. The larger the value of the first wiring radius is, the smaller the concentration of the etching solution is.

3. The method for balancing radial and tangential bridge resistance based on etching solution concentration according to claim 2, characterized in that: In the first corresponding relationship, When the first wiring radius is between 3 and 7 mm, the etching solution concentration is between 13 and 15%; When the first wiring radius is between 4 and 8 mm, the etching solution concentration is between 10 and 12%; When the first wiring radius is between 5 and 9 mm, the etching solution concentration is between 7 and 9%; When the first wiring radius is between 7 and 12 mm, the etching solution concentration is between 4 and 6%.

4. The method for balancing radial and tangential bridge resistance based on etching solution concentration according to claim 1, characterized in that: In the second corresponding relationship, the value of the second wiring radius is negatively correlated with the concentration of the etching solution. The larger the value of the second wiring radius is, the smaller the concentration of the etching solution is.

5. The method for balancing radial and tangential bridge resistance based on etching solution concentration according to claim 4, characterized in that: In the second corresponding relationship, When the second wiring radius is between 0.1 and 3 mm, the etching solution concentration is between 13 and 15%; When the second wiring radius is between 0.1 and 4 mm, the etching solution concentration is between 10 and 12%; When the second wiring radius is between 0.1 and 5 mm, the etching solution concentration is between 7 and 9%. When the second wiring radius is between 0.1 and 7 mm, the etching solution concentration is between 4 and 6%.

6. The method for balancing radial and tangential bridge resistance based on etching solution concentration according to claim 1, characterized in that: The pressure sensor is an MCS pressure sensor.

7. The method for balancing radial and tangential bridge resistance based on etching solution concentration according to claim 1, characterized in that: The etching of the sensitive gate of the pressure sensor according to the concentration of the etching solution further includes: Acquire a first processing line width corresponding to the radial sensitive gate and a second processing line width corresponding to the tangential sensitive gate, wherein the first processing line width and the second processing line width have a second corresponding relationship, and the first processing line width is greater than the second processing line width; The sensitive gate of the pressure sensor is etched according to the first processing line width, the second processing line width, and the etching solution concentration.

8. The method for balancing radial and tangential bridge resistance based on etching solution concentration according to claim 1 or 7, characterized in that: A preset threshold of a difference between the radial sensitive gate resistance value and the tangential sensitive gate resistance value after etching is determined according to the first wiring radius, the second wiring radius, the first processing line width, and the second processing line width.

9. An MCS pressure sensor, the MCS pressure sensor is prepared based on the radial and tangential bridge resistance balancing method based on etching solution concentration according to any one of claims 1 to 8, characterized in that: The MCS pressure sensor includes a sensitive material layer, an elastomer layer and a fusion layer; the sensitive material layer includes a radial sensitive grid and a tangential sensitive grid, the radial sensitive grid and the tangential sensitive grid form a Wheatstone bridge structure, the radial sensitive grid and the tangential sensitive grid are coaxial and arranged in the same plane, the tangential sensitive grid is arranged at the axis, and the radial sensitive grid is arranged near the circumference; a blind hole structure is processed at one end of the elastomer layer away from the sensitive material layer, and the elastomer layer is used to receive stress; a fusion layer, the fusion layer is coated on the elastic layer, and is used for the joint pressure fusion of the sensitive material layer and the elastomer layer.

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