Pressure module structure and method

Abstract

The invention discloses a pressure module structure and method, and relates to the technical field of pressure sensing, the pressure module structure comprises a ceramic base, a ceramic elastic membrane and a pressure sensing circuit; the ceramic base is internally provided with a through hole which penetrates along the thickness direction and is provided with a plated-through hole wall, and is filled with a conductive filling body which is electrically connected with the plated-through hole wall; a groove is formed in the back face of the ceramic base, a signal conditioning and trimming circuit electrically connected with the pressure sensing circuit is arranged in the groove, and the ceramic side wall of the groove provides physical barrier protection for the circuit. One end of the through hole is electrically connected with the pressure sensing circuit, and the other end of the through hole is electrically connected with the signal conditioning and trimming circuit, so that the pressure sensing circuit is electrically connected with the signal conditioning and trimming circuit through the plated-through hole wall and the conductive filling body, and pin connection or lead connection is replaced; therefore, the reliability of internal electrical connection and a trimming structure is improved, the risk of mechanical stress and aging failure is reduced, and high integration, miniaturization and low-cost manufacturing of the pressure module are facilitated.

Description

Technical Field

[0001] This invention relates to the field of pressure sensing technology, and in particular to a pressure module structure and method. Background Technology

[0002] Pressure sensors are widely used in industrial control, automotive electronics, medical devices, and intelligent equipment. Their core function is to stably and accurately convert external pressure signals into electrical signals and output them. As applications evolve towards higher reliability, miniaturization, and mass production, pressure sensor modules face higher requirements in terms of structural integration, electrical connection reliability, and resistance to mechanical stress.

[0003] One type of pressure sensing technology typically uses a ceramic diaphragm as the elastomer, on which a piezoresistive circuit is formed through thick-film printing. This is combined with processes such as multilayer low-temperature glass paste sintering and laser trimming to form a thin-film dual-layer piezoresistive sensing core. This approach directly screen-prints a Wheatstone bridge onto the ceramic diaphragm surface and then electrically connects it to the trimming circuit on the ceramic substrate surface via through-hole metallization. While this method has the advantage of mature manufacturing processes, the trimming circuit and connection structure are exposed on the core surface, making them susceptible to external vibration, impact, and assembly stress. Long-term use can lead to insufficient connection reliability and decreased signal stability.

[0004] Another type of pressure sensor module typically employs a split structure, placing the pressure-sensitive chip within a housing cavity and securing it with adhesive. It is then connected to the circuit board and external circuitry via leads or pins, while the signal processing chip is soldered to the back of the circuit board. This type of solution has multiple structural layers, with components primarily connected via adhesive bonding and soldering. Under high and low temperature cycling or long-term service conditions, issues such as adhesive aging and solder joint fatigue can easily lead to decreased measurement stability and hinder the miniaturization and high integration of the module.

[0005] Some pressure sensor modules attempt to improve integration by combining the ceramic plate in the sensing area with the ceramic plate in the die-casting area, and using conductive pillars injected into the microgrooves in the sidewalls to achieve electrical and structural connections. However, in this type of solution, the conductive pillars often become stress concentration points on one side, and the thermal expansion coefficients of the conductive paste and the ceramic material do not match. Under external force loading or alternating hot and cold environments, there is a risk of detachment or intermittent connection, affecting sensing accuracy and long-term reliability.

[0006] In addition, some pressure sensor modules achieve temperature or stress compensation by setting compensation components on the surface of a ceramic substrate, combined with a metal shell, spring, and sliding parts. While this type of structure can mitigate environmental impact to some extent, it has a complex overall structure, involves many assembly steps, and is prone to introducing additional mechanical stress during assembly. Furthermore, the external pin-type connection method has limitations in terms of vibration resistance and miniaturization, and the manufacturing cost is relatively high.

[0007] In summary, the existing technology has at least the following technical problems: Existing pressure sensors suffer from insufficient reliability of internal electrical connections and adjustment structures, and the risk of mechanical stress and aging failure is easily introduced by multi-layer stacking and connection methods. Furthermore, their complex structure and limited connection methods hinder the high integration, miniaturization, and low-cost manufacturing of pressure sensor modules. Summary of the Invention

[0008] The purpose of this invention is to provide a pressure module structure and method to solve the technical problems of existing pressure sensors, such as insufficient reliability of internal electrical connections and adjustment structures, the risk of mechanical stress and aging failure due to multi-layer stacking and connection methods, and the complex structure and limited connection methods, which are not conducive to the high integration, miniaturization and low-cost manufacturing of pressure sensor modules.

[0009] The preferred technical solutions among the many technical solutions provided by this invention can produce a variety of technical effects, which are described in detail below.

[0010] To address the aforementioned technical problems, the present invention provides the following technical solution: This invention provides a pressure module structure, including a ceramic base; a ceramic elastic diaphragm assembled with the ceramic base to form a pressure-acting surface; a pressure-sensing circuit disposed on the surface of the ceramic elastic diaphragm and / or the ceramic base; at least one through-hole formed in the ceramic base and extending along the thickness direction, the through-hole having a metallized hole wall; a conductive filler filling the through-hole and electrically connected to the metallized hole wall; and a groove formed on the back side of the ceramic base, the groove housing a signal conditioning circuit and / or trimming circuit and its electronic components electrically connected to the pressure-sensing circuit, and the ceramic sidewall of the groove providing a physical barrier protection for the signal conditioning circuit and / or trimming circuit and its electronic components; wherein, one end of the through-hole is electrically connected to the pressure-sensing circuit, and the other end of the through-hole is electrically connected to the signal conditioning circuit and / or trimming circuit in the groove, so that the pressure-sensing circuit and the signal conditioning circuit and / or trimming circuit are electrically interconnected through the metallized hole wall and the conductive filler, replacing pin connections or lead connections.

[0011] In one embodiment, the opening edge of the groove is provided with a step or a limiting surface, so that the highest point of the signal conditioning circuit and / or trimming circuit and its electronic components is not higher than the outer surface of the back of the ceramic base, thereby reducing the risk of damage caused by external vibration or collision.

[0012] In one embodiment, the conductive filler is a conductive paste, a metal adhesive, and / or a sintered conductor, and the conductive filler forms a continuous axial conductive path within the through hole to shorten the signal transmission path and improve the signal response rate.

[0013] In one embodiment, the pressure sensing circuit is a piezoresistive Wheatstone bridge circuit; the signal conditioning circuit and / or trimming circuit includes circuit units for trimming or compensating the zero point, sensitivity and / or temperature drift parameters of the Wheatstone bridge, and is disposed in the groove, and is electrically connected to the piezoresistive Wheatstone bridge circuit through the through hole, the metallized hole wall and the conductive filler.

[0014] In one embodiment, the pressure sensing circuit is a capacitive pressure sensing circuit; the signal conditioning circuit includes a capacitance measurement and conversion unit for converting capacitance changes into voltage signals or digital signals, and is interconnected with the capacitive pressure sensing circuit through the through-hole, the metallized hole wall, and the conductive filler.

[0015] In one embodiment, the metallized hole wall is a metallization layer formed from one or more of silver, copper, nickel, and gold, and the metallization layer is a single-layer or multi-layer composite structure to improve the corrosion resistance and long-term conductivity reliability of the via interconnect.

[0016] In one embodiment, the signal conditioning circuit includes an amplification, filtering, analog-to-digital conversion, and / or temperature compensation unit; a temperature sensor is also disposed in the groove, and the temperature sensor is electrically connected to the temperature compensation unit to achieve combined temperature and pressure compensation.

[0017] A method for manufacturing a pressure module structure is also provided, comprising the following steps: S1, machining a groove: providing a ceramic base and a ceramic elastic diaphragm, and machining a groove on the back side of the ceramic base; S2. Forming a circuit: A pressure sensing circuit is formed on the surface of the ceramic elastic diaphragm and / or the ceramic base; S3. Manufacturing through holes: forming at least one through hole in the ceramic substrate, and metallizing the hole wall to form a metallized hole wall; S4. Filling with conductive material: Filling the through hole with conductive filler material and curing or sintering it to form a conductive filler that is electrically connected to the metallized hole wall; S5. Circuit connection within the groove: A signal conditioning circuit and / or trimming circuit and its electronic components are formed or installed within the groove, and are electrically connected to the pressure sensing circuit through the through hole, the metallized hole wall, and the conductive filler. S6. Assembly: Assemble and encapsulate the ceramic elastic diaphragm with the ceramic base to obtain the pressure module.

[0018] In one embodiment, the metallization process in S3 includes one or more of electroplating, electroless plating, sputtering, screen printing of metal paste, and sintering; the conductive filler material in S4 is a conductive paste or metal adhesive, and after curing or sintering, it forms a continuous axial conductive path in the through hole.

[0019] In one embodiment, in S5, the conditioning chip of the signal conditioning circuit and / or trimming circuit is disposed in the circuit of the groove by flip-chip interconnect, surface mount or wafer-level mounting, and in S6, the groove is encapsulated and sealed. The encapsulation and sealing includes one or more of glass dielectric encapsulation, cover plate encapsulation and / or potting material encapsulation to improve moisture resistance, corrosion resistance and vibration resistance.

[0020] The beneficial effects of this invention are as follows: (1) Improve the reliability of internal electrical connections and adjustment structures, and enhance vibration and shock resistance. This technical solution forms a groove on the back of the ceramic base and places the signal conditioning circuit and / or trimming circuit and its electronic components, which are electrically connected to the pressure sensing circuit, inside the groove. The ceramic sidewall of the groove provides a physical barrier to protect the circuit and components. This avoids the conditioning / trimming circuit from being directly exposed to the outside and affected by external mechanical forces such as vibration, collision, and scratch, significantly reducing the risk of damage, disconnection, or poor connection of solder joints / contacts / trimming points, and improving the long-term stability and consistency of the output signal.

[0021] (2) Reduce the risk of mechanical stress and aging failure caused by multi-layer stacking and external connections. This technical solution forms an axial interconnection path through the thickness direction of the ceramic substrate by "metallized hole wall + conductive filler in the through hole", enabling direct electrical interconnection between the pressure sensing circuit and the conditioning / adjustment circuit in the groove, thus replacing pin connection or lead connection. This interconnection method reduces the number of lead soldering points, pin contact points and adhesive fixing points commonly found in traditional layered stacking structures, reducing the probability of poor contact or conduction failure caused by material aging, thermal cycling stress and fretting wear, thereby improving reliability and measurement stability under long-term service conditions.

[0022] (3) Shorten the signal transmission path and improve the signal response rate and anti-interference capability. Because the interconnected vias form a continuous axial electrical connection path, the signal from the pressure sensing circuit can be quickly transmitted to the signal conditioning circuit within the groove via the metallized hole walls and conductive filler. This avoids the problems of increased parasitic resistance / inductance / capacitance caused by long leads, pins, and exposed pads, which helps to reduce signal attenuation and noise coupling, thereby improving the signal response rate and output stability, and meeting the higher response requirements for dynamic pressure measurement.

[0023] (4) Promote high integration and miniaturization of modules, and reduce manufacturing costs and assembly complexity. This technical solution places the conditioning / adjustment circuitry at the rear and embeds it into the groove on the back of the ceramic base, achieving an integrated layout of the core and the conditioning / adjustment function. At the same time, it replaces pin / lead wire connections with through-hole interconnects, which significantly reduces the dependence of the overall structure's dimensions on external connections. This reduces the number of parts and assembly steps, reduces mechanical stress and consistency fluctuations introduced by assembly, and helps to improve the yield of mass production and reduce manufacturing and maintenance costs.

[0024] (5) Enhance environmental adaptability and long-term stability The key interconnects of this technical solution are located inside the ceramic substrate, including through holes, metallized hole walls, and conductive fillers inside the holes. The conditioning / adjustment circuit is located in the ceramic groove and is protected by the ceramic sidewalls. Compared with exposed solder joints / pin contact structures, it is less susceptible to the effects of moisture, corrosive media, and external pollutants, thereby further reducing the risk of connection failure caused by environmental factors and improving the reliable operation of the module under complex working conditions.

[0025] In summary, this technical solution, through a collaborative design of "rear recessed protection + through holes + metallized hole walls + conductive through hole filling interconnection", simultaneously resolves the contradictions between connection reliability, mechanical stress and aging failure, and miniaturization and low-cost manufacturing at the structural level, which can significantly improve the signal output stability, measurement accuracy and long-term reliability of the pressure module. Attached Figure Description

[0026] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a structural schematic diagram of the pressure module structure of the present invention; Figure 2 This is a schematic diagram of the pressure module structure of the present invention with steps set in the groove; Figure 3 This is a schematic diagram of the pressure module structure of the present invention with a limiting surface set in the groove; Figure 4 This is a schematic diagram of the structure of the pressure sensing circuit of the present invention, which is a piezoresistive Wheatstone bridge circuit; Figure 5 This is a schematic diagram of the structure of the pressure sensing circuit of the present invention, which is a capacitive pressure sensing circuit; Figure 6This is a schematic diagram of the process steps for manufacturing the pressure module structure according to the present invention.

[0028] The reference numerals in the attached figures are as follows: 1. Ceramic base; 11. Through hole; 111. Metallized hole wall; 112. Conductive filler; 12. Groove; 121. Step; 122. Limiting surface; 2. Ceramic elastic diaphragm; 3. Pressure sensing circuit; 31. Piezoresistive Wheatstone bridge circuit; 32. Capacitive pressure sensing circuit; 4. Signal conditioning circuit; 5. Adjust the circuit. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0030] The specific implementation provides a pressure module structure and method. The pressure module structure includes a ceramic base, a ceramic elastic diaphragm, and a pressure sensing circuit. The ceramic base has a through-hole extending along its thickness direction and having a metallized hole wall, filled with a conductive filler electrically connected to the metallized hole wall. A groove is formed on the back of the ceramic base, within which a signal conditioning and adjustment circuit electrically connected to the pressure sensing circuit is disposed. The ceramic sidewall of the groove provides a physical barrier protection for the circuit. One end of the through-hole is electrically connected to the pressure sensing circuit, and the other end is electrically connected to the signal conditioning and adjustment circuit, allowing the pressure sensing circuit and the signal conditioning and adjustment circuit to be electrically interconnected through the metallized hole wall and the conductive filler, thereby replacing pin connections or lead connections. This improves the reliability of the internal electrical connection and adjustment structure, reduces the risk of mechanical stress and aging failure, and facilitates the high integration, miniaturization, and low-cost manufacturing of the pressure module. It effectively solves the technical problems of existing pressure sensors, such as insufficient reliability of the internal electrical connection and adjustment structure, the risk of mechanical stress and aging failure due to multi-layer stacking and connection methods, and the limited connection methods due to complex structures, which hinder the high integration, miniaturization, and low-cost manufacturing of pressure sensor modules.

[0031] The first implementation of the pressure module structure is as follows: Figure 1As shown, the device includes a ceramic base 1; a ceramic elastic diaphragm 2 assembled with the ceramic base 1 to form a pressure-acting surface; a pressure-sensing circuit 3 disposed on the surface of the ceramic elastic diaphragm 2 and / or the ceramic base 1; at least one through hole 11 formed in the ceramic base 1 and extending along the thickness direction, the through hole 11 having a metallized hole wall 111; a conductive filler 112 filled in the through hole 11 and electrically connected to the metallized hole wall 111; and a groove 12 formed on the back side of the ceramic base 1, the groove 12 being provided with a pressure-sensing circuit 3 electrically connected to it. The signal conditioning circuit 4 and / or trimming circuit 5 and their electronic components are provided with a physical barrier protection for the signal conditioning circuit 4 and / or trimming circuit 5 and their electronic components by the ceramic sidewall of the groove 12; wherein, one end of the through hole 11 is electrically connected to the pressure sensing circuit 3, and the other end of the through hole 11 is electrically connected to the signal conditioning circuit 4 and / or trimming circuit 5 in the groove 12, so that the pressure sensing circuit 3 and the signal conditioning circuit 4 and / or trimming circuit 5 are electrically interconnected through the metallized hole wall 111 and the conductive filler 112, so as to replace the pin connection or lead connection.

[0032] Specifically, compared to existing pressure sensors, which generally suffer from insufficient reliability of internal electrical connections and adjustment structures, the risk of mechanical stress and aging failure due to multi-layer stacking and connection methods, and the limitations of complex structures and connection methods that hinder high integration, miniaturization, and low-cost manufacturing, the innovative pressure module structure of this technical solution has at least the following technical advantages: improved reliability of internal electrical connections and adjustment structures, and enhanced resistance to vibration and impact; this technical solution forms a groove 12 on the back of the ceramic base 1, and places the signal conditioning circuit 4 and / or adjustment circuit 5, which are electrically connected to the pressure sensing circuit 3, and their electronic components within the groove 12. The ceramic sidewall of the groove 12 provides a physical barrier to protect the circuit and components; thereby avoiding the direct exposure of the conditioning / adjustment circuit 5 to external mechanical forces such as vibration, collision, and scratches, significantly reducing the risk of damage, disconnection, or poor connection of solder joints / contacts / adjustment points, and improving the long-term stability and consistency of the output signal.

[0033] This technology reduces the risk of mechanical stress and aging failure caused by multi-layer stacking and external connections. It forms an axial interconnection path through the thickness direction of the ceramic base 1 by "metallized hole wall 111 through hole 11 + conductive filler 112 inside through hole 11", which enables direct electrical interconnection between the pressure sensing circuit 3 and the conditioning / adjustment circuit 5 in the groove 12, and replaces the pin connection or lead connection. This interconnection method reduces the number of lead soldering points, pin contact points and adhesive fixing points commonly found in traditional layered stacking structures, and reduces the probability of poor contact or conduction failure caused by material aging, thermal cycling stress and fretting wear, thereby improving the reliability and measurement stability under long-term service conditions.

[0034] Shortening the signal transmission path improves the signal response rate and anti-interference capability. Since the interconnected vias 11 form a continuous axial electrical connection path, the signal from the pressure sensing circuit 3 can be quickly transmitted to the signal conditioning circuit 4 in the groove 12 via the metallized hole wall 111 and the conductive filler 112. This avoids the problem of increased parasitic resistance / parasitic inductance / parasitic capacitance caused by long leads, pins and exposed pads, which helps to reduce signal attenuation and noise coupling, thereby improving the signal response rate and output stability, and meeting the higher response requirements for dynamic pressure measurement.

[0035] This technology promotes high integration and miniaturization of modules, reducing manufacturing costs and assembly complexity. The conditioning / adjustment circuit 5 is placed at the rear and embedded in the groove 12 on the back of the ceramic base 1, realizing an integrated layout of the core and the conditioning / adjustment function. At the same time, the interconnection through the through hole 11 replaces the pin / lead connection, which significantly reduces the dependence of the overall structure's size and external connection. This reduces the number of parts and assembly steps, reduces the mechanical stress and consistency fluctuations introduced by assembly, and helps to improve the yield of mass production and reduce manufacturing and maintenance costs.

[0036] This technology enhances environmental adaptability and long-term stability. The key interconnects are located inside the ceramic substrate, including through-holes 11, metallized hole walls 111, and conductive fillers 112. The conditioning / adjustment circuit 5 is located within the ceramic groove 12 and protected by the ceramic sidewalls. Compared to exposed solder joints / pin contact structures, this technology is less susceptible to the effects of moisture, corrosive media, and external pollutants, thereby further reducing the risk of connection failures caused by environmental factors and improving the module's reliable operation under complex working conditions.

[0037] In summary, this technical solution, through the collaborative design of "back recess 12 recessed protection + through hole 11 + metallized hole wall 111 + through hole 11 conductive filling interconnection", simultaneously solves the contradiction between connection reliability, mechanical stress and aging failure, miniaturization and low-cost manufacturing at the structural level, which can significantly improve the signal output stability, measurement accuracy and long-term reliability of the pressure module.

[0038] As one alternative implementation method: Regarding the arrangement of the aforementioned groove 12 protection signal conditioning circuit 4 and / or trimming circuit 5 and their electronic components, this embodiment, for example... Figure 2 and Figure 3 As shown, the opening edge of the groove 12 is provided with a step 121 or a limiting surface 122, so that the highest point of the signal conditioning circuit 4 and / or the trimming circuit 5 and its electronic components is not higher than the outer surface of the back of the ceramic base 1, so as to reduce the risk of damage caused by external vibration or collision.

[0039] In application, the step 121 or limiting surface 122 at the edge of the opening of the groove 12 is used to form a high constraint and force shield for the signal conditioning circuit 4 and / or trimming circuit 5 and their electronic components within the groove 12: On the one hand, the step 121 / limiting surface 122 limits the installation height of components such as circuit boards / chips / capacitors, ensuring that their highest point is not higher than the outer surface of the back of the ceramic base 1, thereby causing external assembly clamping, transportation vibration or accidental collisions to act preferentially on the ceramic base 1 body rather than the circuit component body, reducing the risk of failure such as solder joint cracking, chip chipping, and device detachment; on the other hand, the step 121 structure and the sidewall of the groove 12 together form a "recessed protective cavity", which works in conjunction with the axial interconnection of the through hole 11 to place the conditioning / trimming adjustment points that are susceptible to external influences in the rear and embed them, avoiding the wear, impact and environmental invasion problems caused by the traditional exposed surface trimming circuit 5, thereby improving the long-term reliability and output stability of the internal electrical connection and trimming structure, and reducing measurement drift and consistency fluctuations caused by assembly stress coupled to the circuit components.

[0040] In a preferred embodiment, the step 121 or the limiting surface 122 may be a continuous annular step 121, a segmented limiting rib, or multiple point limiting posts; a buffer space for accommodating potting material may be formed between the step 121 and the bottom surface of the groove 12; the surface of the step 121 may be provided with a roughened texture or a local positioning groove to improve the resistance to displacement of the circuit board / chip; a cover plate, ceramic sealing plate, or glass medium cover may also be provided at the opening of the groove 12 to further improve the moisture-proof, dust-proof, and corrosion-resistant capabilities.

[0041] Regarding the specific configuration of the conductive filler 112 described above, this embodiment is as follows: Figure 1 As shown, the conductive filler 112 is a conductive paste, metal adhesive and / or sintered conductor. The conductive filler 112 forms a continuous axial conductive path in the through hole 11 to shorten the signal transmission path and improve the signal response rate.

[0042] The conductive filler 112 forms a continuous axial conductive path in the through hole 11. Its function is to replace the external connection method of pins or leads with "axial interconnection inside the ceramic substrate". During execution, conductive paste or metal glue is injected into the through hole 11 and cured / sintered to form a dense conductor pillar, so that the electrical connection terminal on the pressure sensing circuit 3 side is directly connected to the electrical connection terminal on the conditioning / adjustment circuit 5 side in the groove 12 through a short path.

[0043] The axial conductive path works in conjunction with the metallized hole wall 111 to reduce parasitic parameters and poor contact risks introduced by long leads, pin contacts and multiple solder points, thereby improving signal response rate and anti-interference capability. On the other hand, it reduces assembly stress and the number of aging failure points caused by adhesive bonding and pin pressing, structurally reducing the risk of loose connections and open circuits caused by thermal cycling and fretting wear, thereby improving measurement stability and batch consistency, and facilitating module miniaturization and low-cost assembly.

[0044] In some embodiments, the conductive filler 112 may be made of silver paste, silver-copper composite paste, copper paste, or a conductive paste system containing a glass phase, and "vacuum-assisted injection / pressurized injection" may be used to avoid air bubbles in the hole; the conductive filler 112 may be configured as a single hole single pillar, a double hole in parallel, or a multi-hole array interconnection to achieve redundant conduction; the cross-section of the through hole 11 may be circular, elliptical, or elongated to adapt to different current carrying and layout requirements; the end of the conductive filler 112 may be formed with a boss or pad to improve the contact area with the circuit terminal and the reliability of welding / bonding.

[0045] Regarding the specific configuration of the aforementioned metallized hole wall 111, this embodiment is as follows: Figure 1 As shown, the metallized hole wall 111 is a metallization layer formed by one or more of silver, copper, nickel, and gold, and the metallization layer is a single layer or a multi-layer composite structure to improve the corrosion resistance and long-term conductivity reliability of the interconnect of the via 11.

[0046] The function of the metallized hole wall 111 is to provide stable interface conductivity and environmental failure resistance for the interconnection of the via 11. During execution, a metallization layer is formed on the hole wall of the via 11 through electroplating, electroless plating, sputtering or sintering, so that a reliable electrical connection interface is formed between the conductive filler 112 and the ceramic hole wall. The metallized hole wall 111 and the conductive filler 112 work together to reduce the interface peeling and contact resistance fluctuation caused by direct contact between ceramic and conductor. By selecting corrosion-resistant layers such as nickel / gold or composite structures, oxidation and electrochemical migration caused by moisture and corrosive media are suppressed, thereby improving the long-term conductivity reliability of the interconnection of the via 11. At the same time, the hole wall metallization makes the current distribution of the conductive path more uniform, reduces local hot spots and single-point stress concentration, and, together with the protective structure embedded in the groove 12, improves the output drift and instability caused by mechanical stress and environmental factors.

[0047] In addition, the metallized hole wall 111 adopts a multilayer system such as "Cu / Ni / Au" or "Ag / Ni / Au", in which the nickel layer serves as a barrier layer and the gold layer serves as an anti-oxidation layer. The metallization of the hole wall is combined with pretreatment such as plasma cleaning and roughening activation to improve adhesion, and a thickened ring is formed in the hole opening area to improve the hole opening crack resistance and welding reliability. For high reliability scenarios, densification reflow or secondary sintering is performed after metallization to reduce the microporosity of the hole wall.

[0048] A second implementation of the pressure module structure, for example Figure 4 As shown, the difference between this embodiment and the first embodiment is that the pressure sensing circuit 3 is a piezoresistive Wheatstone bridge circuit 31; the signal conditioning circuit 4 and / or trimming circuit 5 include circuit units for trimming or compensating the zero point, sensitivity and / or temperature drift parameters of the Wheatstone bridge, and are disposed in the groove 12, and are electrically connected to the piezoresistive Wheatstone bridge circuit 31 through the through hole 11, the metallized hole wall 111 and the conductive filler 112.

[0049] When the pressure sensing circuit 3 is a piezoresistive Wheatstone bridge circuit 31, the circuit unit used for zero-point, sensitivity, and / or temperature drift parameter adjustment or compensation is placed in the groove 12 on the back of the ceramic base 1, and electrically connected to the Wheatstone bridge through through-hole 11—metallized hole wall 111—conductive filler 112. This achieves the coupling of "post-embedded adjustment function" and "low-stress interconnection": during execution, the output terminal of the Wheatstone bridge is axially interconnected into the groove 12 through through-hole 11, and the adjustment / compensation circuit adjusts the bridge bias and gain. The parameters such as temperature drift coefficient are calibrated and compensated. Since the adjustment point and conditioning device are located in the groove 12 and are limited and protected by the ceramic sidewall and step 121, the vibration and impact damage and contact drift caused by the exposure of the traditional surface adjustment circuit 5 are avoided. At the same time, the poor contact and aging failure points caused by the pins / leads are reduced, thereby significantly improving the output stability, long-term consistency and anti-environment interference capability of the piezoresistive pressure measurement, and solving the problems of "insufficient reliability of adjustment structure, easy failure of connection method and assembly stress affecting accuracy" in the existing technology.

[0050] A third implementation of the pressure module structure, for example Figure 5 As shown, the difference between this embodiment and the first embodiment is that the pressure sensing circuit 3 is a capacitive pressure sensing circuit 32; the signal conditioning circuit 4 includes a capacitance measurement and conversion unit, which is used to convert capacitance changes into voltage signals or digital signals, and is interconnected with the capacitive pressure sensing circuit 32 through the through hole 11, the metallized hole wall 111 and the conductive filler 112.

[0051] When the pressure sensing circuit 3 is a capacitive pressure sensing circuit 32, by placing the capacitance measurement and conversion unit in the groove 12 and interconnecting it with the capacitive sensing circuit through the through hole 11—metallized hole wall 111—conductive filler 112, the acquisition of capacitance signals with "short path and low parasitic parameters" can be achieved. During execution, the capacitance change signal is directly transmitted to the measurement and conversion unit in the groove 12 through axial interconnection, reducing parasitic capacitance and noise coupling introduced by long leads and exposed pads, and improving capacitance measurement resolution and dynamic response. At the same time, the embedded protection in the groove 12 reduces the drift risk of the measurement circuit caused by mechanical shock and environmental erosion, making the process of converting capacitance change into voltage signal or digital signal more stable and reliable. This solves the problem of output instability caused by long capacitance signal links, susceptibility to interference, and insufficient connection reliability in the prior art, and is conducive to module miniaturization and integrated layout.

[0052] The fourth embodiment of the pressure module structure differs from the first embodiment in that the signal conditioning circuit 4 includes an amplification, filtering, analog-to-digital conversion and / or temperature compensation unit; a temperature sensor is also provided in the groove 12, and the temperature sensor is electrically connected to the temperature compensation unit to achieve joint temperature and pressure compensation.

[0053] When the signal conditioning circuit 4 includes amplification, filtering, analog-to-digital conversion, and / or temperature compensation units, and a temperature sensor is installed in the groove 12, end-to-end conditioning and temperature drift suppression of the pressure signal can be achieved. During execution, the output of the pressure sensing circuit 3 is axially interconnected into the groove 12 through the through hole 11. First, the amplification and filtering unit improves the signal-to-noise ratio and suppresses high-frequency noise. Then, the analog-to-digital conversion unit realizes digital output. At the same time, the temperature sensor collects the module's operating temperature in real time and inputs it into the temperature compensation unit to compensate for zero-point drift, sensitivity drift, or nonlinearity. Since the conditioning and compensation elements are located in the groove 12 and protected by the ceramic sidewall and step 121 structure, and the interconnection path is short and the connection points are few, the risk of assembly stress coupling and aging failure can be reduced. The output stability and measurement accuracy under complex working conditions such as thermal cycling and vibration shock can be significantly improved, thereby solving the problems of "difficult-to-control temperature drift, stress-induced error due to complex structure, and long-term instability due to insufficient connection reliability" in the prior art.

[0054] Based on the above embodiments of the pressure module structure, a method for manufacturing the pressure module structure is provided, such as... Figure 6 As shown, the process includes the following steps performed sequentially from S1 to S6: S1, processing the groove: providing a ceramic base and a ceramic elastic diaphragm, and processing a groove on the back of the ceramic base; S2. Circuit Formation: A pressure sensing circuit is formed on the surface of the ceramic elastic diaphragm and / or ceramic substrate. S3. Manufacturing through holes: forming at least one through hole in the ceramic substrate and metallizing the hole wall to form a metallized hole wall; S4. Filling with conductive material: Filling the through hole with conductive filler material and curing or sintering it to form a conductive filler that is electrically connected to the metallized hole wall; S5. In-groove circuit connection: A signal conditioning circuit and / or trimming circuit and its electronic components are formed or installed in the groove, and are electrically connected to the pressure sensing circuit through through holes, metallized hole walls and conductive filler. S6. Assembly: Assemble and encapsulate the ceramic elastic diaphragm with the ceramic base to obtain the pressure module.

[0055] Specifically, the metallization process in S3 includes one or more of electroplating, electroless plating, sputtering, screen printing of metal paste, and sintering; the conductive filler material in S4 is a conductive paste or metal adhesive, which forms a continuous axial conductive path in the through hole after curing or sintering.

[0056] In S5, the conditioning chip of the signal conditioning circuit and / or trimming circuit is placed in the circuit of the groove using flip-chip interconnect, surface mount or wafer-level mounting. In S6, the groove is encapsulated and sealed. The encapsulation and sealing includes one or more of glass dielectric encapsulation, cover plate encapsulation and / or potting material encapsulation to improve moisture resistance, corrosion resistance and vibration resistance.

[0057] In application, this method achieves integrated manufacturing of the pressure module through a process chain of "back recessed protection + through-hole metallization + axial interconnection of conductive filler in the hole + wafer-level / flip-chip mounting and sealing of conditioning chips in the recess": First, in S1, a recess is formed on the back of the ceramic substrate, allowing subsequent signal conditioning circuits and / or trimming circuits and their electronic components to be embedded and protected by the physical barrier of the ceramic sidewall; then, in S2, a pressure sensing circuit is formed on the surface of the ceramic elastic diaphragm and / or the ceramic substrate, so that the pressure-sensitive signal is generated near the pressure application surface, at a closer distance; in S3, through-holes are formed by drilling / laser / mechanical processing, and the hole walls are metallized by electroplating, chemical plating, sputtering or screen printing of metal paste and sintering to form metallized hole walls, giving the through-hole a stable interface conductivity base. In step S4, conductive paste or metal adhesive is filled into the through-hole and cured / sintered to form a conductive filler that is reliably electrically connected to the metallized hole wall, thereby establishing a continuous axial conductive path inside the ceramic substrate. In step S5, signal conditioning circuits and / or trimming circuits and their electronic components are installed in the groove, and they are connected to the pressure sensing circuit through the through-hole—metallized hole wall—conductive filler to form a short-path electrical connection. The conditioning chip can be embedded in the groove circuit using flip-chip interconnect, surface mount, or wafer-level mounting to reduce interconnect length and reduce unstable connections such as exposed solder joints / leads / pins. Finally, in step S6, the ceramic elastic diaphragm and ceramic substrate are assembled and packaged, and the groove is sealed with glass dielectric encapsulation, cover plate encapsulation, and / or potting material encapsulation to further suppress connection failures caused by moisture, corrosion, and vibration shock.

[0058] Therefore, this method and structural solution work together to reduce aging failure points and assembly stress coupling caused by multi-layer stacking and bonding / pins / leads, shorten signal links to improve response rate and output stability, and improve environmental adaptability through groove embedding and encapsulation sealing. From the process level, it solves the problems of "insufficient reliability of internal electrical connection and adjustment structure, high risk of mechanical stress and aging failure, complex structure and not conducive to miniaturization and low-cost manufacturing" in the existing technology, and improves batch manufacturing consistency and yield.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described.

Claims

1. A pressure module structure, characterized in that, Including ceramic base; And a ceramic elastic diaphragm assembled with the ceramic base to form a pressure-acting surface; And a pressure sensing circuit disposed on the surface of the ceramic elastic diaphragm and / or the ceramic base; And at least one through hole formed in the ceramic substrate and extending along the thickness direction, the through hole having a metallized hole wall; And a conductive filler that fills the through hole and is electrically connected to the metallized hole wall; And a groove formed on the back of the ceramic base, wherein a signal conditioning circuit and / or trimming circuit and its electronic components are disposed in the groove and are electrically connected to the pressure sensing circuit, and the ceramic sidewall of the groove provides a physical barrier protection for the signal conditioning circuit and / or trimming circuit and its electronic components. One end of the through hole is electrically connected to the pressure sensing circuit, and the other end of the through hole is electrically connected to the signal conditioning circuit and / or adjustment circuit in the groove, so that the pressure sensing circuit and the signal conditioning circuit and / or adjustment circuit are electrically interconnected through the metallized hole wall and the conductive filler, thereby replacing the pin connection or lead connection.

2. The pressure module structure according to claim 1, characterized in that, The opening edge of the groove is provided with a step or a limiting surface, so that the highest point of the signal conditioning circuit and / or trimming circuit and its electronic components is not higher than the outer surface of the back of the ceramic base, thereby reducing the risk of damage caused by external vibration or collision.

3. The pressure module structure according to claim 1, characterized in that, The conductive filler is a conductive paste, metal adhesive, and / or sintered conductor. The conductive filler forms a continuous axial conductive path within the through hole to shorten the signal transmission path and improve the signal response rate.

4. The pressure module structure according to claim 1, characterized in that, The pressure sensing circuit is a piezoresistive Wheatstone bridge circuit. The signal conditioning circuit and / or trimming circuit includes circuit units for trimming or compensating the zero point, sensitivity, and / or temperature drift parameters of the Wheatstone bridge, and is disposed in the groove, and is electrically connected to the piezoresistive Wheatstone bridge circuit through the through hole, the metallized hole wall, and the conductive filler.

5. The pressure module structure according to claim 1, characterized in that, The pressure sensing circuit is a capacitive pressure sensing circuit. The signal conditioning circuit includes a capacitance measurement and conversion unit for converting capacitance changes into voltage signals or digital signals, and is interconnected with the capacitive pressure sensing circuit through the through-hole, the metallized hole wall, and the conductive filler.

6. The pressure module structure according to claim 1, characterized in that, The metallized hole wall is a metallization layer formed from one or more of silver, copper, nickel, and gold, and the metallization layer is a single-layer or multi-layer composite structure to improve the corrosion resistance and long-term conductivity reliability of the through-hole interconnect.

7. The pressure module structure according to claim 1, characterized in that, The signal conditioning circuit includes amplification, filtering, analog-to-digital conversion and / or temperature compensation units; A temperature sensor is also provided in the groove, and the temperature sensor is electrically connected to the temperature compensation unit to achieve joint temperature and pressure compensation.

8. A method for manufacturing the pressure module structure according to any one of claims 1-7, characterized in that, The process includes the following steps: S1, machining the groove: providing a ceramic base and a ceramic elastic diaphragm, and machining a groove on the back of the ceramic base; S2. Forming a circuit: A pressure sensing circuit is formed on the surface of the ceramic elastic diaphragm and / or the ceramic base; S3. Manufacturing through holes: forming at least one through hole in the ceramic substrate, and metallizing the hole wall to form a metallized hole wall; S4. Filling with conductive material: Filling the through hole with conductive filler material and curing or sintering it to form a conductive filler that is electrically connected to the metallized hole wall; S5. Circuit connection within the groove: A signal conditioning circuit and / or trimming circuit and its electronic components are formed or installed within the groove, and are electrically connected to the pressure sensing circuit through the through hole, the metallized hole wall, and the conductive filler. S6. Assembly: Assemble and encapsulate the ceramic elastic diaphragm with the ceramic base to obtain the pressure module.

9. The method according to claim 8, characterized in that, The metallization process described in S3 includes one or more of electroplating, electroless plating, sputtering, screen printing of metal paste, and sintering. The conductive filler material in S4 is a conductive paste or metal adhesive, and after curing or sintering, it forms a continuous axial conductive path in the through hole.

10. The method according to claim 8, characterized in that, In S5, the conditioning chip of the signal conditioning circuit and / or trimming circuit is placed in the circuit of the groove using flip-chip interconnect, surface mount, or wafer-level mounting. In S6, the groove is encapsulated and sealed. The encapsulation and sealing includes one or more of glass dielectric encapsulation, cover plate encapsulation, and / or potting material encapsulation to improve moisture resistance, corrosion resistance, and vibration resistance.

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