High-power-overload-resistant small silicon piezoresistive pressure sensor and manufacturing method thereof

Abstract

The invention relates to the technical field of silicon-based MEMS sensors, in particular to a high-power overload resistant small silicon piezoresistive pressure sensor and a manufacturing method thereof. The sensor is provided with a master-slave deflection mechanism in which a metal elastic diaphragm draws a metal corrugated diaphragm to deflect along with pressure deflection, and when overload pressure exceeds a set upper limit, incompressible liquid between the metal corrugated diaphragm and a metal corrugated substrate is completely guided. No incompressible liquid transmits the measured pressure and prevents the overrun overload pressure from acting on the sensitive chip, so that the irreversible failure of the sensor caused by the yield or fracture of the sensitive chip is avoided. Under the condition that piezoresistive effect sensitivity does not need to be sacrificed and the radial size is not increased, the intrinsic pressure overload capacity of the silicon piezoresistive pressure sensitive chip is improved in order of magnitude, and even the intrinsic pressure overload capacity of a micro-pressure or low-pressure sensor can be improved by hundreds of times or more. The method is especially suitable for long-term reliable measurement of low and micro pressure in a high and wide measuring range, wherein the upper limit of the measured pressure measuring range is prone to step sudden change.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon-based MEMS sensors, and in particular to a small silicon piezoresistive pressure sensor resistant to high overload and a manufacturing method thereof. Background Art

[0002] The pressure overload capacity of silicon piezoresistive pressure sensors generally depends on the intrinsic pressure overload capacity of the sensitive chip, that is, the overload capacity solidified by the structural dimensions of the silicon pressure-sensitive diaphragm of the chip. Due to the inverse relationship between the sensitivity of the silicon piezoresistive pressure-sensitive chip and the thickness of the pressure-sensitive diaphragm, the upper limit of the chip's intrinsic overload pressure is generally not greater than several times the rated pressure range, and is far away from the limit pressure at which the pressure-sensitive diaphragm yields or ruptures. When a measured pressure load below the overload pressure upper limit is applied to the sensor, it will never irreversibly degrade or damage the performance parameters and functions of the sensor. When the measured pressure load returns to the rated range, the performance parameters of the ideal elastic silicon sensor return to normal.

[0003] In practical applications, it is difficult to avoid that the measured pressure, especially the measured pressure peak of the micro-pressure and low-pressure range, will change transiently, greatly exceeding the set upper limit of the sensor's overload capacity, causing the sensitive chip silicon pressure-sensitive diaphragm with limited overload capacity to yield or rupture instantly and fail permanently. The design of increasing the thickness of the pressure-sensitive diaphragm while keeping the surface area unchanged can improve the pressure overload capacity of the pressure-sensitive diaphragm, but at the expense of sensitivity, the sensor's accuracy and signal-to-noise ratio will degrade. Although the use of a pressure cut-off valve or switch in front of the sensor measurement interface can effectively prevent the application of pressure loads that damage the sensor, the volume and weight of the sensor will increase significantly, reducing the applicability of miniaturization and lightweighting of the sensor.

[0004] To this end, we propose a small silicon piezoresistive pressure sensor that can withstand high overload and a manufacturing method thereof. Summary of the invention

[0005] The main purpose of the present invention is to provide a small silicon piezoresistive pressure sensor with a master-slave deflection mechanism in which a metal elastic diaphragm deflects with pressure to pull a metal corrugated diaphragm to deflect, and a method for manufacturing the same. The function of the master-slave deflection mechanism is that when the overload pressure reaches a certain set value, the metal elastic diaphragm begins to deflect, expanding the initial filling volume of the variable volume cavity of the sensor, and the incompressible liquid between the metal corrugated diaphragm and the corrugated substrate is diverted into the variable volume cavity of the expanded volume. When the overload pressure increases to the safety upper limit set value, the filling liquid between the metal corrugated diaphragm and the corrugated substrate is completely diverted. Without the transmission of incompressible liquid, the continuously increasing overload pressure load is refused to be transmitted to the sensitive chip, and the deflection of the chip pressure-sensitive diaphragm ends within the elastic range far away from the yield limit of the diaphragm. When the measured pressure load returns to normal working conditions, driven by the rebound of the deflection of the metal elastic diaphragm, the diverted liquid flows back to the corrugated diaphragm and the corrugated substrate, and the sensor function and performance indicators return to normal. Without sacrificing the initial sensitivity of the sensor, the intrinsic pressure overload capacity of conventional silicon piezoresistive pressure sensors can be increased by orders of magnitude, and even the intrinsic pressure overload capacity of micro-pressure or low-pressure sensors can be increased by a hundred times or more. It is particularly suitable for long-term reliable measurement of measured pressures with a range upper limit prone to step changes or low and micro pressures with a wide range, and can effectively solve the problems described in the background technology.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A small silicon piezoresistive pressure sensor resistant to high overload, the sensor structure includes a metal isolation corrugated diaphragm, a metal corrugated substrate, an incompressible liquid, a silicon piezoresistive pressure sensitive chip, a small-caliber metal tube seat, a metal capillary liquid guide tube, a metal support column, a variable volume chamber metal bottom plate, a metal elastic diaphragm and a metal foil electrode soft belt, the metal isolation corrugated diaphragm is statically pressed by a flat diaphragm fixed on the periphery of the corrugated surface of the metal corrugated substrate, when there is no filler interval, the upper and lower corresponding peaks and troughs of the two can be fitted without gaps, the corrugated surface of the metal corrugated substrate is provided with a cross-shaped capillary liquid guide groove, the center of the cross-shaped capillary liquid guide groove is located at the center of the metal corrugated substrate, and a capillary guide groove is provided on the center of the circle. Liquid through hole, the cross-shaped capillary liquid guide groove runs through each corrugated ring, the side wall of the metal corrugated substrate is provided with a liquid filling hole and a Euro-shaped ring compression groove, the liquid filling hole is connected to the capillary liquid guide through hole, the Euro-shaped ring compression groove is adjacent to the bottom end of the metal corrugated substrate, the small-diameter metal tube seat inner column is eccentrically provided with a liquid guide capillary through hole, the bottom end of the inner column The center of the circle is provided with a capillary liquid guide tube and a fixed support through hole and a fixed support blind hole of the metal support column, the two holes are equal in diameter, and the hole centers are symmetrical in distance from each other. The liquid guide capillary through hole is connected to the metal capillary liquid guide tube and the fixed support hole, and the hole centers overlap up and down. The center of the inner column of the small-diameter metal tube seat is provided with a pressure-conducting capillary hole, and the bottom electrode of the small-diameter metal tube seat is connected to the metal foil electrode soft belt.

[0008] The metal-isolated liquid-sealed silicon piezoresistive pressure sensor has a master-slave deflection mechanism in which the metal elastic diaphragm deflects with the pressure to pull the metal corrugated diaphragm to deflect. When the overload pressure is greater than a certain set value, the metal elastic diaphragm of the variable volume chamber deflects and displaces along the direction of pressure action, expanding the volume of the variable volume chamber. The incompressible liquid filled between the metal corrugated diaphragm and the metal corrugated substrate is introduced into the variable volume chamber with the enlarged volume through the connected capillaries. When the filling liquid between the corrugated diaphragm and the corrugated substrate to which it is fixed is completely cleaned, the peaks and troughs of the two are completely fitted, and there is no incompressible liquid to transmit the increment of the overload pressure in real time and in equal amounts, refusing to transmit the destructive overload pressure to the sensitive chip, and the deflection of the chip pressure-sensitive diaphragm ends within the elastic range far away from the yield limit of the pressure-sensitive diaphragm. When the measured pressure load returns to normal working conditions, the deflection displacement of the metal elastic diaphragm returns to its original position. Driven by the deflection and rebound of the metal elastic diaphragm, the guided incompressible liquid flows back to the space between the corrugated diaphragm and the metal corrugated substrate, and the sensor function and performance indicators return to normal.

[0009] In order to achieve the complete fit between the crests and troughs of the metal corrugated diaphragm and the crests and troughs of the metal corrugated substrate, it is necessary to first air-tightly weld the periphery of the flat metal diaphragm to the periphery of the metal corrugated substrate. With the metal corrugated substrate as a mold, the corrugations of the flat diaphragm formed by static pressure are consistent with the corrugated shape of the metal corrugated substrate. The metal corrugated substrate is provided with liquid guide capillary through holes and capillary grooves, and the side wall is provided with liquid filling holes and Euro-ring compression grooves, and the Euro-ring compression grooves are adjacent to the bottom of the metal corrugated substrate.

[0010] A capillary hole for conducting ambient atmospheric pressure is arranged at the center of the inner column of the small-diameter metal tube seat, a capillary through hole for conducting liquid is arranged eccentrically on the inner column, and a fixed through hole and a fixed blind hole belonging to the capillary conducting tube and the metal support column are arranged on both sides of the center of the back side respectively. The center positions of the two holes are symmetrical, and the center position of the fixed through hole coincides with the center position of the eccentric capillary through hole for conducting liquid.

[0011] After the sensitive chip is fixed on the tube seat and the bonding wire is connected, the bottom of the metal corrugated substrate of the fixed metal corrugated diaphragm is airtightly welded to the top of the tube seat pressure measurement cavity. The sensitive chip on the tube seat is airtightly isolated from the ambient atmosphere and the measured pressure medium. The sensitive chip pressure-sensitive diaphragm is designed to be a peak diaphragm structure, so that the low-pressure and micro-pressure sensitive chips still have a good balance between intrinsic sensitivity, nonlinearity and pressure overload capacity without increasing the surface area.

[0012] The incompressible liquid variable volume cavity is formed by airtight fusion welding of a metal smooth bottom plate with the same diameter and a metal elastic diaphragm around it. A metal capillary liquid guide tube fixed support through hole and a metal connecting column fixed support blind hole are eccentrically arranged on the bottom plate. The hole center and the aperture center are symmetrical. The center of one of the eccentric through holes coincides with the center of the liquid guide through hole of the tube seat.

[0013] The metal elastic diaphragm is made of an alloy with excellent Young's modulus, which has strong deflection repeatability, stability and fatigue life. Before being airtightly welded with the metal base plate of the variable volume cavity, the shape and size of the corrugated structure have been statically shaped by the diaphragm. The volume of the cavity formed with the base plate will change with the deflection of the elastic diaphragm driven by the measured pressure. The thickness and waveform design of the corrugation of the metal elastic diaphragm are related to the multiple of the rated range of the measured pressure. The starting pressure of the elastic diaphragm deflection is set to be greater than the upper limit pressure of the rated range of the sensor, which will not affect the accuracy of the normal measurement of the sensor. The pressure at which the metal elastic diaphragm stops deflecting is much smaller than the yield limit pressure of the pressure-sensitive diaphragm. The volume expanded by the maximum deflection of the elastic diaphragm is sufficient to accommodate all the filling liquids that are diverted between the metal corrugated diaphragm and the metal corrugated substrate.

[0014] The material selection of the thick-walled metal liquid-conducting capillary and the connecting column is the same as that of the tube seat. The two ends of the liquid-conducting capillary are concentrically welded with the eccentric through hole at the bottom of the tube seat and the eccentric through hole of the metal bottom plate of the variable volume cavity, forming a flow guide and reflux path for incompressible liquid between the corrugated diaphragm and the elastic diaphragm. The two ends of the connecting column are concentrically welded with the eccentric blind hole at the bottom of the tube seat and another eccentric through hole of the metal bottom plate of the variable volume cavity, balancing and reinforcing the verticality and strength of the rigid connection between the tube seat and the bottom plate.

[0015] The hot vacuum trickle method is used to purify and fill incompressible liquids. After the liquid is filled and before the filling hole is sealed, the liquid volume between the corrugated diaphragm and the corrugated substrate is regulated by the control device of the metal corrugated diaphragm adsorption vacuum degree. The liquid volume control is compatible with the thermal expansion and contraction of the liquid, which causes the metal corrugated diaphragm to fit the corrugated substrate in advance or delay. After the liquid volume is adjusted, the sensor is removed from the control device, and the incompressible liquid filling hole is sealed with a welded steel ball or a metal pin.

[0016] The metal foil soft belt is electrically connected to the tube holder electrode pins, extending the sensor external connection electrodes.

[0017] Beneficial effects of the present invention:

[0018] The present invention discloses a small silicon piezoresistive pressure sensor that can withstand high overloads and a method for making the same. The sensor utilizes a master-slave deflection mechanical mechanism in which a metal elastic diaphragm deflects with pressure to pull a metal corrugated diaphragm to deflect. This mechanism improves the intrinsic pressure overload capacity of the metal-isolated liquid-sealed silicon piezoresistive pressure sensor by orders of magnitude without sacrificing sensitivity or increasing radial dimensions. Even the intrinsic pressure overload capacity of a micro-pressure or low-pressure sensor can be improved by a hundred times or more. The sensor is particularly suitable for long-term reliable measurement of pressures whose upper limit of the range is prone to step changes or low and micro-pressures with a wide range. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0020] Figure 1It is a top view schematic diagram of the corrugated structure surface of the metal corrugated substrate of the present invention;

[0021] Figure 2 The metal corrugated substrate of the present invention is Figure 1 Longitudinal schematic diagram of the dashed cross section;

[0022] Figure 3 The metal isolation corrugated diaphragm of the present invention is fixedly supported by the periphery of the corrugated substrate. Figure 1 Longitudinal schematic diagram of the dashed cross section;

[0023] Figure 4 It is a longitudinal schematic diagram of the cross section of the small-diameter metal pipe seat of the present invention;

[0024] Figure 5 is a schematic top view of a variable volume chamber bottom plate of the present invention;

[0025] Figure 6 The variable volume chamber of the present invention is Figure 5 Longitudinal schematic diagram of the dashed cross section;

[0026] Figure 7 The invention provides a small metal-isolated liquid-sealed silicon piezoresistive pressure sensor capable of withstanding high overload. Figure 1 Longitudinal schematic diagram of the dashed cross section;

[0027] In the figure: 1. Metal isolation corrugated diaphragm; 1-1. Diaphragm corrugation; 2. Metal corrugated substrate; 2-1. Capillary liquid conduction hole; 2-2. Capillary liquid conduction groove; 2-3. Liquid filling hole; 2-4. Euro ring compression groove; 3. Incompressible liquid; 4. Silicon piezoresistive pressure sensitive chip; 4-1. Pressure-sensitive diaphragm; 5. Small-diameter metal tube seat; 5-1. Liquid conduction capillary through hole; 5-2. Pressure conduction capillary hole; 5-3. Metal capillary liquid conduction tube fixed support through hole; 5-4. Metal connecting column fixed support blind hole; 6-1. Metal capillary liquid conduction tube; 6-2. Metal support column; 7. Variable volume chamber metal bottom plate; 7-1. Variable volume chamber; 7-2. Fixed support through hole; 8. Metal elastic diaphragm; 9. Metal foil electrode soft belt. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0029] As an embodiment of the present invention, Figure 1-Figure 7As shown, the high-overload-resistant small silicon piezoresistive pressure sensor of the present invention comprises a metal isolation corrugated diaphragm 1, a metal corrugated substrate 2, an incompressible liquid 3, a silicon piezoresistive pressure sensitive chip 4, a small-caliber metal tube seat 5, a metal capillary liquid guide tube 6-1, a metal support column 6-2, a variable-volume chamber metal bottom plate 7, a metal elastic diaphragm 8 and a metal foil soft belt 9;

[0030] The metal isolation corrugated diaphragm 1 is formed by static pressure of a flat metal diaphragm of the same diameter welded on the periphery of the corrugated surface of the metal corrugated substrate 2, and the formed corrugations are a replica of the corrugations on the metal corrugated substrate 2;

[0031] The corrugated surface of the metal corrugated substrate 2 is provided with a cross-shaped capillary liquid conducting groove 2-2, the center of the cross is located at the center of the metal corrugated substrate 2, and a capillary liquid conducting through hole 2-1 is provided on the center of the circle. The cross-shaped capillary liquid conducting groove 2-2 passes through each corrugated ring, and the side wall of the metal corrugated substrate 2 is provided with a liquid filling hole 2-3 and a Euro-shaped ring compression groove 2-4, the liquid filling hole 2-3 is connected to the capillary liquid conducting through hole 2-1, the Euro-shaped ring compression groove 2-4 is adjacent to the bottom end of the metal corrugated substrate 2, and the periphery of the bottom end is fused with the periphery of the top of the sensor pressure measurement cavity of the small-caliber metal tube seat 5 fixedly supporting the sensitive chip 4, and is connected to the capillary liquid conducting through hole 2-1;

[0032] Before being welded to the periphery of the bottom end of the metal corrugated substrate 2, the pressure sensitive chip 4 is packaged on the inner column of the small-diameter metal tube seat 5 with the pressure-conducting hole 5-2. The inner column of the small-diameter metal tube seat 5 is eccentrically provided with a liquid-conducting capillary hole 5-1, and the two sides of the bottom center are respectively provided with a fixed support through hole 5-3 and a fixed support blind hole 5-4 connecting the metal capillary liquid-conducting tube 6-1 and the metal support column 6-2, the two holes have equal diameters, and the hole centers are symmetrically spaced from each other, and the liquid-conducting capillary through hole 5-1 overlaps with the center of the metal capillary liquid-conducting tube 6-1 and the fixed support through hole 5-3;

[0033] The bottom plate 7 of the variable volume chamber is eccentrically provided with two fixed through holes 7-2 connecting the metal liquid-conducting capillary 6-1 and the metal support column 6-2. The two holes have the same diameter, and the hole diameters are closely matched with the outer diameters of the metal liquid-conducting capillary 6-1 and the metal support column 6-2. The hole centers are symmetrical in distance from each other, and the center of one of the through holes overlaps with the center of the liquid-conducting capillary through hole 5-1 of the small-diameter metal tube seat 5 in upper and lower directions.

[0034] One end of the metal capillary liquid guide tube 6-1 and the metal support column 6-2 are respectively welded to the peripheries of the fixed support through hole 5-3 and the fixed support blind hole 5-4 at the bottom end of the small-diameter metal tube seat 5, and the other end are respectively welded to the peripheries of the two fixed support through holes 7-2 on the metal bottom plate 7 of the variable volume chamber;

[0035] The periphery of the metal elastic diaphragm 8 is welded to the periphery of the bottom end of the metal bottom plate 7 of the variable volume chamber, and the gap between the two constitutes a variable volume chamber 7-1 for the incompressible liquid 3, which is connected to the pressure measurement chamber of the small-caliber metal tube seat 5 through the metal capillary liquid guide tube 6-1;

[0036] The incompressible liquid 3 passes through the liquid filling hole 2-3 and fills the cavities and gaps interconnected by the metal isolation corrugated diaphragm 1 and the corrugated substrate 2, the small-diameter metal tube seat 5 fixedly supporting the sensitive chip cavity, the metal liquid-conducting capillary 6-1, and the variable volume chamber 7-1. After the amount of the incompressible liquid 3 is quantitatively controlled, the liquid filling hole 2-3 is sealed;

[0037] The metal foil soft belt 9 is electrically connected to the electrode pins of the small-diameter metal tube seat 5 to extend the external connection electrode of the sensor.

[0038] The master-slave deflection mechanism in which the metal elastic diaphragm deflects with the pressure to pull the metal isolation corrugated diaphragm to deflect has the function of preventing excessive overload pressure from being applied to the sensitive chip of the sensor without sacrificing sensitivity and without increasing the radial dimension of the sensor: when the overload pressure is greater than a certain set value, the metal elastic diaphragm of the incompressible liquid variable volume chamber deflects and displaces along the direction of pressure action to expand the volume of the variable volume chamber. The incompressible liquid filled between the metal isolation corrugated diaphragm and the metal corrugated substrate is introduced into the variable volume chamber with enlarged volume through the connected capillaries. When the incompressible liquid between the metal isolation corrugated diaphragm and the metal corrugated substrate to which it is fixed is completely drained, the peaks and troughs of the two are completely fitted, and there is no incompressible liquid to transmit the increment of overload pressure in real time and in equal amounts, so that destructive overload pressure is prevented from being transmitted to the sensitive chip, and the deflection of the chip pressure-sensitive diaphragm ends within the elastic range far away from the yield limit of the diaphragm. When the measured pressure load returns to normal working conditions, the deflection displacement of the metal elastic diaphragm returns to its original position. Driven by the deflection and rebound of the metal elastic diaphragm, the incompressible liquid is guided back to the metal isolation corrugated diaphragm and the metal corrugated substrate, and the sensor function and performance indicators return to normal. The intrinsic pressure overload capacity of conventional silicon piezoresistive pressure sensitive chips is increased by an order of magnitude, and even the intrinsic pressure overload capacity of micro-pressure or low-pressure sensors can be increased by a hundred times or more.

[0039] A method for manufacturing a small silicon piezoresistive pressure sensor capable of withstanding high overload, comprising the following steps:

[0040] S1, the metal isolation corrugated diaphragm 1 is a flat circular diaphragm before corrugation forming, and after the periphery is airtightly rigidly fixed on the periphery of the corrugated surface of the metal corrugated substrate 2, the flat circular diaphragm is statically pressed to form the metal isolation corrugated diaphragm 1, and the diaphragm corrugation 1-1 is a replica of the substrate corrugation 2-1;

[0041] S2, after the pressure sensitive chip 4 is packaged on the inner column of the small-diameter metal tube seat 5 with or without the pressure-conducting hole 5-2, the bottom periphery of the metal corrugated substrate 2 of the same diameter is airtightly and rigidly fixed to the top periphery of the shell of the small-diameter metal tube seat 5. The periphery of one end of the metal capillary liquid guide tube 6-1 and the periphery of one end of the metal support column 6-2 are airtightly and rigidly fixed to the periphery of the fixed through hole 5-3 and the fixed blind hole 5-4 at the bottom of the tube seat 5 respectively;

[0042] S3, the other end of the metal liquid-conducting capillary 6-1 and the metal support column 6-2 are rigidly fixed to the bottom of the two fixed through holes 7-1 in the bottom plate 7 of the variable volume chamber by airtight rigidity;

[0043] S4, the periphery of the metal elastic diaphragm 8 is rigidly fixed to the bottom periphery of the variable volume chamber bottom plate 7 in an airtight manner;

[0044] S5, after the incompressible liquid 3 is purified by thermal vacuum, it drips and fills into the pressure measuring cavity of the sensor;

[0045] S6. A device for regulating the deflection of the metal isolation corrugated diaphragm 1 by vacuum adsorption is used to adjust the gap between the metal isolation corrugated diaphragm 1 and the corrugated substrate 2 to regulate the amount of the incompressible liquid 3. The liquid amount regulation is synchronously compatible with the early or delayed working condition of overload pressure rejection caused by thermal expansion and contraction of the liquid 3;

[0046] S7, after the liquid volume is quantitatively regulated, the incompressible liquid 3 filling hole 2-3 is sealed by a fusion-welded steel ball or a metal pin, and the incompressible liquid 3 in the pressure measuring cavity of the sensor is solidified;

[0047] S8. The metal foil soft belt 9 is connected to the bottom electrode of the small-diameter metal tube seat 5 by soldering.

[0048] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A small silicon piezoresistive pressure sensor capable of withstanding high overload, characterized in that: The sensor comprises a metal isolation corrugated diaphragm (1), a metal corrugated substrate (2), an incompressible liquid (3), a silicon piezoresistive pressure sensitive chip (4), a small-caliber metal tube seat (5), a metal capillary liquid guide tube (6-1), a metal support column (6-2), a variable volume chamber metal bottom plate (7), a metal elastic diaphragm (8) and a metal foil electrode soft belt (9).

2. A high-overload-resistant small silicon piezoresistive pressure sensor according to claim 1, characterized in that: The metal isolation corrugated diaphragm (1) is formed by static pressure of a flat diaphragm fixed on the periphery of the corrugated surface of the metal corrugated substrate (2). When there is no filler spacer, the corresponding upper and lower crests and troughs of the two can fit together without gaps.

3. A high-overload-resistant small silicon piezoresistive pressure sensor according to claim 2, characterized in that: The corrugated surface of the metal corrugated substrate (2) is provided with a cross-shaped capillary liquid conducting groove (2-2), the center of the cross-shaped capillary liquid conducting groove is located at the center of the circle of the metal corrugated substrate (2), a capillary liquid conducting through hole (2-1) is provided at the center of the circle, the cross-shaped capillary liquid conducting groove (2-2) passes through each corrugated ring, the side wall of the metal corrugated substrate (2) is provided with a liquid filling hole (2-3) and a Euro-shaped ring compression groove (2-4), the liquid filling hole (2-3) is connected to the capillary liquid conducting through hole (2-1), and the Euro-shaped ring compression groove (2-4) is adjacent to the bottom end of the metal corrugated substrate (2).

4. The high-overload-resistant small silicon piezoresistive pressure sensor according to claim 1, characterized in that: A liquid-conducting capillary through hole (5-1) is eccentrically arranged on the inner column of the small-diameter metal tube seat (5), and a metal capillary liquid-conducting tube (6-1) and a fixed support through hole (5-3) and a fixed support blind hole (5-4) of the metal support column (6-2) are respectively arranged on both sides of the center of the circle at the bottom end of the inner column, the two holes have equal diameters, and the hole centers are symmetrically spaced from each other, the liquid-conducting capillary through hole (5-1) is connected to the metal capillary liquid-conducting tube (6-1) and the fixed support hole (5-3), and the hole centers overlap each other, a pressure-conducting capillary hole (5-2) is arranged at the center of the inner column of the small-diameter metal tube seat (5), and the bottom electrode of the small-diameter metal tube seat (5) is connected to a metal foil electrode soft belt (9).

5. A high-overload-resistant small silicon piezoresistive pressure sensor according to claim 4, characterized in that: The upper and lower ends of the metal liquid-conducting capillary tube (6-1) are respectively connected to the liquid-conducting capillary through hole (5-1) of the tube seat (5) and the fixed support through hole (7-2) of the bottom plate (7) of the variable volume chamber, forming a reciprocating channel for the diversion and reflux of the incompressible liquid. The upper and lower ends of the metal support column (6-2) are respectively connected to the fixed support blind hole (5-4) of the tube seat (5) and another fixed support through hole (7-2) of the bottom plate (7) of the liquid variable volume chamber.

6. The high-overload-resistant small silicon piezoresistive pressure sensor according to claim 5, characterized in that: The outer diameter of the variable volume chamber bottom plate (7) is smaller than the outer diameter of the small-diameter metal tube seat (5), and a fixed support through hole (7-1) for connecting the metal liquid-conducting capillary (6-1) and the metal support column (6-2) is eccentrically provided thereon, the two holes having equal diameters, the hole diameters closely matching the outer diameters of the metal liquid-conducting capillary (6-1) and the metal support column (6-2), the hole centers facing each other with central symmetry, and the center of one of the through holes overlaps with the center of the liquid-conducting capillary through hole (5-1) of the small-diameter metal tube seat (5) in upper and lower directions.

7. A high-overload-resistant small silicon piezoresistive pressure sensor according to any one of claims 1 to 6, characterized in that: The manufacturing method of the sensor is as follows: a metal elastic diaphragm (8) with excellent Young's modulus is fixed on the periphery of the bottom end surface of the metal bottom plate (7) of the variable volume chamber to form a variable volume chamber (7-1) for incompressible liquid (3); according to the functional relationship between the deflection of the metal elastic diaphragm (8) fixed on the periphery and the overload pressure, the starting pressure value of the deflection displacement of the metal elastic diaphragm (8) in the direction of the overload pressure is set to be equal to the lower limit value of the overload pressure setting multiple of the sensor; when the overload pressure approaches or reaches the upper limit value of the overload pressure safety multiple setting, the volume of the variable volume chamber (7-1) expanded by the deflection displacement of the metal elastic diaphragm (8) is sufficient to accommodate the amount of the incompressible liquid (3) that is drained away between the metal isolation corrugated diaphragm (1) and the corrugated base plate (2).

8. The high-overload-resistant small silicon piezoresistive pressure sensor according to claim 7, characterized in that: The incompressible liquid (3) uses the liquid filling hole (2-3) as an inlet and fills the interconnected cavities and gaps between the metal isolation corrugated diaphragm (1) and the corrugated substrate (2), the cavity of the small-caliber metal tube seat (5) fixedly supporting the sensitive chip, the metal liquid-conducting capillary (6-1), and the variable-volume chamber (7-1). After the amount of the incompressible liquid (3) is quantitatively controlled, the liquid filling hole (2-3) is sealed.

9. The method for manufacturing a small silicon piezoresistive pressure sensor capable of withstanding high overload according to claim 8, characterized in that: The steps include: S1. The metal isolation corrugated diaphragm (1) is a flat circular diaphragm before corrugation forming. After the periphery is rigidly fixed on the periphery of the corrugated surface of the metal corrugated substrate (2) in an airtight manner, the flat circular diaphragm is statically pressed to form the metal isolation corrugated diaphragm (1). The diaphragm corrugation (1-1) is a replica of the substrate corrugation (2-1); S2, after the pressure sensitive chip (4) is packaged on the inner column of the small-diameter metal tube seat (5) provided with the pressure-conducting hole (5-2), the bottom periphery of the metal corrugated substrate (2) of the same diameter is airtightly and rigidly fixed to the top periphery of the shell of the small-diameter metal tube seat (5). The periphery of one end of the metal capillary liquid guide tube (6-1) and the periphery of one end of the metal support column (6-2) are respectively airtightly and rigidly fixed to the periphery of the fixed through hole (5-3) and the fixed blind hole (5-4) at the bottom of the tube seat (5); S3, the metal liquid-conducting capillary (6-1) and the other end periphery of the metal support column (6-2) are rigidly and airtightly fixed on the bottom periphery of two fixed through holes (7-1) in the bottom plate (7) of the variable volume chamber; S4, the periphery of the metal elastic diaphragm (8) is rigidly fixed airtightly on the periphery of the bottom end of the variable volume chamber bottom plate (7); S5, the incompressible liquid (3) is purified by thermal vacuum and then dripped into the pressure measuring chamber of the sensor; S6. A device for regulating the deflection of the metal isolation corrugated diaphragm (1) by vacuum adsorption is used to adjust the gap between the metal isolation corrugated diaphragm (1) and the corrugated substrate (2) to regulate the amount of the incompressible liquid (3). The liquid amount regulation is synchronously compatible with the advance or delay of the overload pressure rejection caused by the thermal expansion and contraction of the liquid (3); S7, after the liquid volume is quantitatively regulated, the incompressible liquid (3) filling hole (2-3) is sealed by a welded steel ball or a metal pin, and the incompressible liquid (3) in the pressure measuring cavity of the sensor is solidified; S8, the metal foil electrode soft belt (9) is connected to the bottom electrode of the small-diameter metal tube seat (5) by soldering.

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