Adhesive-free packaging silicon wafer-sintering seat clamping type pressure sensor and packaging method

Abstract

The invention discloses a non-adhesive packaging silicon wafer-sintering seat clamping type pressure sensor and a packaging method, and relates to the technical field of pressure sensors. The sensor comprises a sintering seat, a pressure chip, a first insulating cover, a second insulating cover and an electrical connection part, the first insulating cover and the second insulating cover are spliced to form a square clamping groove for accommodating the pressure chip, and an elastic sheet is arranged on the inner wall of the clamping groove and can elastically deform to flexibly clamp the chip when the chip is inserted; the O-shaped rings in the sealing grooves of the first insulating cover and the second insulating outer wall are extruded and deformed between the sealing grooves and the mounting cavity of the sintering seat, and the generated elastic pre-tightening force is converted into radial friction force, so that the radial movement of the insulating covers can be effectively limited, and the insulating covers are fixed. According to the invention, adhesive is replaced by mechanical clamping, the problems of precision attenuation, insufficient environmental tolerance and production process limitation caused by stress in traditional glue joint packaging are solved, the precision stability and environmental adaptability of the sensor are improved, the production efficiency is improved, and the cost is reduced.

Description

Technical Field

[0001] This application belongs to the field of pressure sensor technology, and specifically relates to a pressure sensor with adhesive-free encapsulated silicon wafer-sintered socket and encapsulation method. Background Technology

[0002] Pressure sensors are core components for detecting pressure signals and are widely used in automotive, medical, and industrial control fields. For a long time, the industry has generally used adhesives (such as epoxy resin or silicone) to fix MEMS sensor chips onto metal sintering substrates. This process typically involves pretreatment of the sintering substrate, including sandblasting and plasma cleaning, followed by precise dispensing and curing to achieve chip bonding and fixation.

[0003] However, this mature process has inherent technical flaws. First, the volume shrinkage of the adhesive during curing and the significant difference in thermal expansion coefficients between the adhesive and the metal / silicon chip introduce continuous shrinkage and thermal stresses on the chip's sensitive diaphragm, causing zero-point drift in the sensor and resulting in irreversible degradation of accuracy. Second, the adhesive's insufficient chemical stability makes it prone to swelling, bulging, and even precipitating substances that contaminate the pressure transmission medium when exposed to media such as silicone oil for extended periods, thus affecting pressure transmission accuracy and shortening sensor lifespan.

[0004] Furthermore, this bonding solution also has limitations in terms of production process. The amount of adhesive applied needs to be precisely controlled, as too much or too little will affect the product yield; the curing process takes a long time, which restricts the improvement of production efficiency; at the same time, the adhesive, as a consumable with the risk of expiration, also increases the complexity and cost of production management.

[0005] Therefore, developing a novel packaging technology that eliminates the need for adhesives and fundamentally solves the aforementioned structural problems has become an urgent technological need in this field. Summary of the Invention

[0006] The purpose of this application is to provide a pressure sensor with a non-adhesive-encapsulated silicon wafer-sintering base and a packaging method. This addresses the problems mentioned in the background art regarding traditional pressure sensor adhesive packaging, such as irreversible accuracy degradation due to adhesive curing shrinkage and stress caused by differences in thermal expansion coefficients between the adhesive and the sintering base / chip, poor environmental tolerance due to insufficient adhesive chemical stability, and limitations in the manufacturing process caused by the adhesive coating and curing steps.

[0007] To achieve the above objectives, this application adopts the following technical solution: In one aspect, a pressure sensor with adhesive-free encapsulated silicon wafer-sintered base is provided, including a sintered base, a pressure chip, an insulating cover, and electrical connection components; The insulating cover includes a first insulating cover and a second insulating cover, and the first insulating cover and the second insulating cover are spliced ​​together to form a square slot inside for accommodating the pressure chip. At least one inner wall of the square slot is provided with an elastic sheet, which is configured to undergo elastic deformation when the pressure chip is inserted into the square slot, thereby forming a flexible clamping and fixing of the pressure chip. The outer wall of the insulating cover is provided with a sealing groove, and an O-ring is provided in the sealing groove. The insulating cover is fixed by the O-ring engaging with the inner wall of the mounting cavity of the sintering seat.

[0008] In one possible implementation, the elastic sheet is integrally formed with the first insulating cover and / or the second insulating cover.

[0009] In one possible implementation, the number of elastic sheets is multiple, and they are distributed on the four corners of the upper side of the square slot and on the inner walls of the left and right sides.

[0010] In one possible implementation, the joint between the first insulating cover and the second insulating cover is provided with mutually cooperating guide positioning pins and positioning holes.

[0011] In one possible implementation, the size of the square slot is a transition fit with the size of the pressure chip.

[0012] In one possible implementation, the insulating cover is made of alumina ceramic material.

[0013] In one possible implementation, the electrical connection component includes gold-plated Kova legs fixed to the sintering base by a glass sintering process, and the pressure chip is bonded to the gold-plated Kova legs by gold wires.

[0014] In one possible implementation, a corrugated diaphragm and a pressure ring are fixed to the sintering seat. The sintering seat has an oil filling hole, which is sealed by welding steel balls. The internal cavity of the sintering seat is filled with silicone oil.

[0015] Secondly, a method for packaging a pressure sensor with a glue-free encapsulated silicon wafer-sintered socket is provided, comprising the following steps: A first insulating cover and a second insulating cover are provided. The pressure chip is snapped into a square slot formed by splicing the first insulating cover and the second insulating cover. The pressure chip is flexibly clamped by an elastic sheet set on the inner wall of the square slot to form a snapping assembly. The locking assembly is installed into the mounting cavity of the sintering base, and the locking assembly is fixed in the sintering base by the locking engagement between the O-ring set in the sealing groove of the outer wall of the insulating cover and the inner wall of the mounting cavity. The pressure chip is electrically connected to the gold-plated Kova tube legs fixed on the sintering base using a gold wire bonding process.

[0016] In one possible implementation, before the engaging assembly is inserted, precise alignment is achieved using guide pins and positioning holes at the junction of the first and second insulating covers to limit the displacement of the pressure chip.

[0017] Compared with the prior art, this application has the following beneficial effects: This application provides a pressure sensor with a non-adhesive-encapsulated silicon wafer-sintered base snap-fit ​​design. The first and second insulating covers are joined to form a square slot, which, combined with an elastic sheet, achieves flexible clamping. This completely eliminates the need for traditional adhesives, fundamentally avoiding the stress caused by adhesive curing shrinkage and the deformation of the chip's sensitive diaphragm due to the difference in thermal expansion coefficients between the adhesive, the sintered base, and the chip. This effectively reduces sensor zero-point drift and improves accuracy stability. Simultaneously, the snap-fit ​​fit between the O-ring and the sintered base mounting cavity ensures that the insulating cover will not loosen radially after installation and prevents the rigid interference fit from cracking the insulating cover, making the sensor more reliable overall.

[0018] In one possible implementation, multiple elastic tabs clamp the pressure chip from the upper corners and inner walls of the square slot at multiple points and in multiple directions. This allows for a more uniform clamping force on the chip, avoiding the chip tilting and force concentration problems that can occur when using only a single elastic tab. This further improves the positional stability of the chip after assembly and reduces micro-deformation caused by uneven force. Simultaneously, the multi-elastic tab structure can also disperse external impacts on the chip. When the sensor encounters vibration or impact, it can better protect the pressure chip, reduce the risk of chip damage, and extend the sensor's lifespan.

[0019] In one possible implementation, the guide pin and positioning hole work together to ensure precise splicing of the first and second insulating covers. This avoids size deviations in the square slot caused by misalignment during manual splicing, ensuring the compatibility of the square slot and the pressure chip, and reducing issues such as the chip being clamped too loosely or too tightly due to incorrect slot dimensions. Simultaneously, precise alignment improves the assembly efficiency of the first and second insulating covers, reduces assembly difficulty, and ensures accurate contact between the elastic sheet and the pressure chip, resulting in more uniform clamping force, reducing product defect rates due to assembly deviations, and improving production efficiency.

[0020] In one possible implementation, the transitional fit between the square slot and the pressure chip ensures smooth chip insertion while reducing the gap between the chip and the inner wall of the slot, preventing the chip from shifting within the slot and improving the positional accuracy after chip assembly. Simultaneously, the transitional fit also helps the elastic sheet better perform its clamping function, reducing excessive deformation of the elastic sheet and extending its lifespan. Furthermore, it provides the chip with sufficient thermal expansion space during temperature changes, preventing chip damage due to thermal expansion and further improving the sensor's stability under temperature cycling conditions.

[0021] In one possible implementation, the corrugated diaphragm exhibits excellent pressure transmission performance, uniformly transferring external pressure to the internal silicone oil, which then transmits it to the pressure chip. This prevents direct contact between the external medium and the pressure chip, protecting it from corrosion and contamination. The pressure ring enhances the connection between the corrugated diaphragm and the sintering seat, preventing the diaphragm from detaching under high pressure. The silicone oil possesses stable physicochemical properties, ensuring stable pressure transmission, reducing losses during pressure transmission, and improving detection accuracy. The steel ball welded seal reliably seals the oil filling hole, preventing silicone oil leakage and ensuring long-term stable operation of the sensor. Furthermore, the steel ball seal structure is simple and effective, reducing the difficulty and cost of the sealing process.

[0022] A method for encapsulating a silicon wafer-sintered socket type pressure sensor without adhesive is disclosed. This method eliminates traditional adhesive bonding processes such as gluing and curing, completely solving various problems associated with adhesives and simplifying the production process. It reduces the single-batch production cycle by more than 30% compared to traditional adhesive bonding processes, thus improving production efficiency. The snap-fit ​​assembly uses modular assembly, reducing assembly difficulty and facilitating automated assembly, minimizing human error. The mature and reliable gold wire bonding process ensures electrical connection quality and reduces product defects caused by electrical connection failures. The entire process eliminates the need for specialized equipment such as dispensing equipment and curing ovens, reducing equipment investment costs. It also eliminates the need for consumables such as adhesives, reducing consumable procurement and management costs, ultimately lowering product production costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of a glue-free encapsulated silicon wafer-sintered base snap-fit ​​pressure sensor provided in this application; Figure 2 A cross-sectional view of a glue-free encapsulated silicon wafer-sintered base snap-fit ​​pressure sensor provided in this application; Figure 3 An assembly diagram of a card engagement component provided in this application; Figure 4 This application provides an overall structural schematic diagram of a first insulating cover; Figure 5 This is a schematic diagram of the overall structure of a second insulating cover provided in this application.

[0024] The attached figures are labeled as follows: 1. Sintering seat; 2. Steel ball; 3. First insulating cover; 4. Second insulating cover; 5. Pressure chip; 6. O-ring; 7. Corrugated diaphragm; 8. Pressure ring; 9. Elastic sheet; 10. Gold-plated Kova tube leg; 11. Silicone oil. Detailed Implementation

[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0026] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] like Figure 1 , Figure 2 and Figure 3 As shown, this application discloses a pressure sensor with a non-adhesive-encapsulated silicon wafer-sintering base 1, comprising a sintering base 1, a pressure chip 5, an insulating cover, and electrical connection components.

[0032] The insulating cover includes a first insulating cover 3 and a second insulating cover 4. When the first insulating cover 3 and the second insulating cover 4 are spliced ​​together, a square slot is formed inside to accommodate the pressure chip 5.

[0033] Optionally, a stainless steel sintering base 1 can be prepared, with an installation cavity inside which can hold the insulating cover; the pressure chip 5 is a square silicon-based MEMS chip. The insulating cover is divided into two parts, left and right, both made of alumina ceramic. When these two insulating covers are put together, a square slot for holding the pressure chip 5 is formed inside.

[0034] At least one inner wall of the square slot is provided with an elastic sheet 9, which is configured to undergo elastic deformation when the pressure chip 5 is inserted into the square slot, thereby forming a flexible clamping and fixing of the pressure chip 5.

[0035] The outer wall of the insulating cover is provided with a sealing groove, and an O-ring 6 is provided in the sealing groove. The insulating cover is fixed by the O-ring 6 engaging with the inner wall of the mounting cavity of the sintering seat 1.

[0036] Optionally, a 0.18mm thick fluororubber elastic sheet 9 is attached to the middle of the left inner wall of the square card slot, and a sealing groove is processed on the outer wall of the first insulating cover 3 and the second insulating cover 4. The cross-sectional dimensions of the groove match the O-ring 6, and the nitrile rubber O-ring 6 is embedded into the sealing groove.

[0037] During assembly, the pressure chip 5 is inserted into the assembled square slot. The chip will squeeze the elastic sheet 9 to deform it, and the reaction force generated by the elastic sheet 9 can flexibly clamp the chip.

[0038] Next, the first insulating cover 3 and the second insulating cover 4, which have been installed, are placed into the mounting cavity of the sintering seat 1. The O-ring 6 is in close contact with the inner wall of the mounting cavity and forms a snap-fit, thus fixing the insulating cover to the sintering seat 1.

[0039] In this embodiment, the first insulating cover 3 and the second insulating cover 4 are joined to form a square slot, which, together with the elastic sheet 9, achieves flexible clamping. This completely eliminates the need for traditional adhesives, fundamentally avoiding the stress caused by adhesive curing shrinkage and the deformation of the chip's sensitive diaphragm due to the difference in thermal expansion coefficients between the adhesive, the sintering base 1, and the chip. This effectively reduces sensor zero-point drift and makes accuracy more stable. Simultaneously, the snap-fit ​​fit between the O-ring 6 and the mounting cavity of the sintering base 1 ensures that the insulating cover will not loosen radially after installation, and also prevents the rigid interference fit from cracking the insulating cover, making the sensor more reliable overall.

[0040] In one possible embodiment, the elastic sheet 9 is integrally formed with the first insulating cover 3 and / or the second insulating cover 4.

[0041] When processing the square slot of the first insulating cover 3, the fluororubber elastic sheet 9 and the first insulating cover 3 are directly molded together using a molding process, and the elastic sheet 9 is placed on the right inner wall of the square slot of the first insulating cover 3.

[0042] The inner left side of the square slot of the second insulating cover 4 is also molded using the same molding process to make the elastic sheet 9 and the second insulating cover 4 into one piece. Both elastic sheets 9 are 0.15mm thick.

[0043] During assembly, the pressure chip 5 is inserted into the square slot where the first insulating cover 3 and the second insulating cover 4 are joined, and the elastic sheets 9 formed on both sides are squeezed. After the sheets are deformed, they clamp the chip. The subsequent assembly method of the O-ring 6 and the sintering seat 1 mounting cavity is as described above.

[0044] In this embodiment, the elastic sheet 9 and the insulating cover are integrally formed, eliminating the need for post-installation bonding of the elastic sheet 9. This saves a step and avoids potential issues such as the elastic sheet 9 detaching or gaps during bonding, resulting in a more secure connection and a more stable structure. Furthermore, the integral forming process ensures precise positioning of the elastic sheet 9 on the insulating cover, leading to more uniform clamping force on the pressure chip 5. This further guarantees the stability of the chip's position after assembly, reducing uneven chip stress caused by inaccurate positioning of the elastic sheet 9 and indirectly improving the sensor's detection accuracy.

[0045] In one possible embodiment, there are multiple elastic pieces 9, which are distributed on the four corners of the upper side of the square slot and on the inner walls of the left and right sides.

[0046] At each of the four corners of the square slot formed by the first insulating cover 3 and the second insulating cover 4, a 2mm×2mm and 0.2mm thick fluororubber elastic sheet 9 is integrally molded using a molding process.

[0047] Meanwhile, on the square slot near the first insulating cover 3 and near the second insulating cover 4, two 3mm×1mm and 0.2mm thick elastic sheets 9 are symmetrically installed on each side, with the thin sheets on the left and right sides evenly distributed along the height direction of the slot.

[0048] During assembly, the pressure chip 5 is inserted into the square slot, and the elastic plates 9 at the four corners of the upper side and the elastic plates 9 on the left and right sides deform together to clamp the chip from multiple directions. The snap-fit ​​method between the O-ring 6 and the mounting cavity of the sintering seat 1 remains unchanged.

[0049] In this embodiment, multiple elastic sheets 9 clamp the pressure chip 5 from the upper corners and the inner walls of the left and right sides of the square slot, providing multi-point and multi-directional clamping. This ensures a more uniform clamping force on the chip, avoiding the chip tilting and force concentration problems that may occur when using only a single elastic sheet 9. This further improves the positional stability of the chip after assembly and reduces micro-deformation caused by uneven force. Simultaneously, the multi-elastic sheet 9 structure can also disperse external impacts on the chip. When the sensor encounters vibration or impact, it can better protect the pressure chip 5, reducing the risk of chip damage and extending the sensor's lifespan.

[0050] In one possible embodiment, the joint between the first insulating cover 3 and the second insulating cover 4 is provided with mutually cooperating guide positioning pins and positioning holes.

[0051] On the splicing surface where the first insulating cover 3 and the second insulating cover 4 meet, three cylindrical positioning holes with a diameter of 2 mm and a depth of 3 mm are machined.

[0052] On the splicing surface of the second insulating cover 4, three guide positioning pins with a diameter of 2mm and a length of 3mm are machined, and the positioning pins and positioning holes adopt a transition fit.

[0053] When assembling the first insulating cover 3 and the second insulating cover 4, the guide positioning pin of the second insulating cover 4 is accurately inserted into the positioning hole of the first insulating cover 3, so that the two insulating covers can be quickly spliced ​​and aligned. The square slot formed after splicing is just the right size to hold the pressure chip 5. The subsequent steps of installing the pressure chip 5 and assembling the O-ring 6 and sintering seat 1 are the same as described above.

[0054] In this embodiment, the guide positioning pin and positioning hole cooperate to ensure precise splicing of the first insulating cover 3 and the second insulating cover 4. This avoids size deviations in the square slot caused by misalignment during manual splicing, ensuring the compatibility of the square slot and the pressure chip 5, and reducing problems such as the chip being clamped too loosely or too tightly due to incorrect slot size. Simultaneously, precise alignment improves the assembly efficiency of the first insulating cover 3 and the second insulating cover 4, reduces assembly difficulty, and ensures accurate contact between the elastic sheet 9 and the pressure chip 5, resulting in more uniform clamping force, reducing product defect rates due to assembly deviations, and improving production efficiency.

[0055] In one possible embodiment, the size of the square slot is a transition fit with the size of the pressure chip 5.

[0056] The pressure chip 5 is a square silicon-based MEMS chip with a side length of 5mm. The square slot formed by splicing the first insulating cover 3 and the second insulating cover 4 is designed with an internal side length of 5mm±0.02mm, so that the size of the slot and the size of the pressure chip 5 can be matched smoothly.

[0057] The elastic sheet 9 is installed on the inner wall of the left side of the square slot, and the snap-fit ​​structure of the O-ring 6 and the sintering seat 1 mounting cavity remains unchanged.

[0058] During assembly, the pressure chip 5 can be smoothly inserted into the square slot, and there is no obvious gap between the inner wall of the slot and the outer wall of the chip. The elastic sheet 9 deforms appropriately to clamp the chip, so that the chip will not wobble due to too large a gap, nor will the chip be damaged due to too large an interference fit.

[0059] In this embodiment, the transition fit between the square slot and the pressure chip 5 ensures smooth chip insertion while reducing the gap between the chip and the inner wall of the slot, preventing the chip from wobbling within the slot and improving the positional accuracy after chip assembly. Simultaneously, the transition fit also helps the elastic sheet 9 better perform its clamping function, reducing excessive deformation of the elastic sheet 9 and extending its service life. Furthermore, it provides the chip with sufficient space for thermal expansion during temperature changes, preventing chip damage due to thermal expansion and further improving the sensor's stability under temperature cycling conditions.

[0060] In one possible embodiment, the insulating cover is made of alumina ceramic material.

[0061] Optionally, both the first insulating cover 3 and the second insulating cover 4 are made of 99% pure alumina ceramic, which is dry-pressed and sintered at high temperature to form the required shape and assembled to form a square slot. The elastic sheet 9 is made of fluororubber and is integrally formed with the insulating cover. The O-ring 6 is made of nitrile rubber. The sintering seat 1 is made of stainless steel, and the pressure chip 5 is a square silicon-based MEMS chip.

[0062] In this embodiment, alumina ceramic exhibits exceptional resistance to acid and alkali corrosion, enabling the insulating cover to operate stably in harsh chemical environments such as strong acids and alkalis. This avoids the corrosion and swelling issues associated with traditional organic insulating covers or adhesives in such conditions, significantly improving the sensor's environmental adaptability. Simultaneously, the high hardness and wear resistance of alumina ceramic reduce wear on the insulating cover during assembly and use, extending its service life. Furthermore, it ensures structural stability, mitigating the decrease in chip clamping force due to material aging, further guaranteeing the sensor's long-term operational reliability.

[0063] In one possible embodiment, the electrical connection component includes a gold-plated Kova tube leg 10 fixed to the sintering base 1, and the pressure chip 5 is bonded to the gold-plated Kova tube leg 10 by a gold wire.

[0064] Optionally, the sintering base 1 is made of stainless steel, with 6 leg mounting holes machined on it. The gold-plated Kova legs 10 are fixed in the mounting holes using a glass sintering process. One end of the gold-plated Kova legs 10 extends out of the sintering base 1 for wiring, while the other end remains inside the sintering base 1.

[0065] The pressure chip 5 is a square silicon-based MEMS chip, housed in a square slot formed by the first insulating cover 3 and the second insulating cover 4, and is manufactured using gold wire ball bonding technology, with a diameter of 25 mm. The gold wire connects the pads of the pressure chip 5 to one end of the gold-plated Kova tube leg 10 inside the sintering seat 1 to achieve electrical conduction. The snap-fit ​​method between the O-ring 6 and the sintering seat 1 remains unchanged.

[0066] In this embodiment, the glass sintering process firmly fixes the gold-plated Kova pin 10 and the sintering base 1 together, while ensuring good sealing and insulation, preventing media leakage due to gaps between the pin and the sintering base 1. The gold-plated Kova pin 10 has excellent conductivity and corrosion resistance, reducing contact resistance at electrical connection points, improving signal transmission efficiency, preventing signal attenuation, and ensuring sensor detection accuracy. The gold wire bonding process provides reliable connections and good conductivity, efficiently achieving electrical connections between the pressure chip 5 and the pin. Furthermore, the gold wire is flexible, adapting to certain thermal expansion and vibration conditions, reducing connection breakage problems caused by thermal stress and vibration, and improving the stability and reliability of the electrical connection.

[0067] In one possible embodiment, the sintering base 1 is further provided with a corrugated diaphragm 7 and a pressure ring 8 fixed on the sintering base 1. The sintering base 1 is provided with an oil filling hole, which is sealed by a welded steel ball 2. The internal cavity of the sintering base 1 is filled with silicone oil 11.

[0068] Optionally, a stainless steel corrugated diaphragm 7 is placed on one end face of the sintering base 1, and a stainless steel pressure ring 8 is placed on top of the corrugated diaphragm 7. The corrugated diaphragm 7 and the pressure ring 8 are welded and fixed at the same time using laser welding technology, so that the two are together firmly fixed to the flat end of the sintering base 1. The corrugated diaphragm 7 is located between the pressure ring 8 and the end face of the sintering base 1. The pressure ring 8 can further enhance the installation firmness of the corrugated diaphragm 7 and prevent it from loosening or shifting during subsequent use.

[0069] Inside the sintering base 1, a 1mm diameter oil filling hole is machined next to the tube leg structure. After the overall sensor assembly process is completed, silicone oil 11 is injected into the internal cavity of the sintering base 1 through this internal oil filling hole, and the oil is continuously injected until the cavity is completely filled with silicone oil and there are no residual gaps.

[0070] Finally, resistance welding was used to weld the stainless steel ball 2 to the oil filling hole to seal the oil filling hole and prevent silicone oil leakage inside the cavity.

[0071] In this embodiment, the corrugated diaphragm 7 exhibits excellent pressure transmission performance, uniformly transmitting external pressure to the internal silicone oil 11, which then transmits it to the pressure chip 5. This prevents direct contact between the external medium and the pressure chip 5, protecting the chip from corrosion and contamination. The pressure ring 8 enhances the connection between the corrugated diaphragm 7 and the sintering seat 1, preventing the diaphragm 7 from detaching under high pressure. The silicone oil 11 possesses stable physicochemical properties, ensuring stable pressure transmission, reducing losses during pressure transmission, and improving detection accuracy. The welded seal of the steel ball 2 reliably seals the oil filling hole, preventing silicone oil 11 leakage and ensuring long-term stable operation of the sensor. Furthermore, the steel ball 2 sealing structure is simple and effective, reducing the difficulty and cost of the sealing process.

[0072] In one possible embodiment, a method for packaging a glue-free encapsulated silicon wafer-sintering base 1 snap-fit ​​pressure sensor is provided, comprising the following steps: The first step is to prepare a first insulating cover 3 and a second insulating cover 4. The left side of the first insulating cover 3 and the right side of the second insulating cover 4 have 0.18mm thick fluororubber elastic sheets 9. At the same time, sealing grooves are machined on the outer walls of the first insulating cover 3 and the second insulating cover 4 respectively, and O-rings 6 are embedded in them. The square pressure chip 5 with a side length of 5mm is first aligned with the corresponding mounting position of the first insulating cover 3 and placed. Then, the positioning hole of the second insulating cover 4 is aligned with the positioning pin of the first insulating cover 3. The first insulating cover 3 and the pressure chip 5 are slowly closed together so that the two insulating covers are spliced ​​together to form a square slot. The pressure chip 5 is placed in the slot. At this time, the fluororubber elastic sheet 9 is deformed by the pressure chip 5 and together with the two insulating covers, clamps the pressure chip 5, completing the assembly of the clamping assembly.

[0073] The second step is to use a special tooling fixture to fix the sintering seat 1. The tooling fixture determines the position of the mounting cavity of the sintering seat 1. The locking assembly is slowly placed into the mounting cavity, and the O-ring 6 is engaged with the inner wall of the mounting cavity to fix the locking assembly.

[0074] The third step is to use a gold wire ball soldering machine to take 25 A gold wire of a certain diameter connects the pressure chip 5 pads and the gold-plated Kova tube legs 10 fixed to the sintering base 1 by glass sintering, completing the electrical connection and obtaining a pressure sensor semi-finished product.

[0075] In this embodiment, the encapsulation method eliminates traditional adhesive bonding processes such as gluing and curing, completely resolving various problems associated with adhesives. It also simplifies the production process, reducing the single-batch production cycle by more than 30% compared to traditional adhesive bonding, thus improving production efficiency. The snap-fit ​​components utilize modular assembly, reducing assembly difficulty, facilitating automated assembly, and minimizing human error. The gold wire bonding process is mature and reliable, ensuring electrical connection quality and reducing product defects caused by electrical connection failures. The entire process eliminates the need for specialized equipment such as dispensing equipment and curing ovens, reducing equipment investment costs. It also eliminates the need for consumables like adhesives, reducing consumable procurement and management costs, ultimately lowering product production costs.

[0076] In one possible embodiment, such as Figure 4 and Figure 5 As shown, before the snap-fit ​​assembly is installed, precise alignment is achieved through the guide positioning pins and positioning holes at the joint of the first insulating cover 3 and the second insulating cover 4 to limit the displacement of the pressure chip 5.

[0077] Specifically, three positioning holes with a diameter of 2mm and a depth of 3mm are machined on the splicing surface of the first insulating cover 3, and three guide positioning pins with a diameter of 2mm and a length of 3mm are machined on the splicing surface of the second insulating cover 4.

[0078] In this embodiment, before the clamping assembly is installed into the sintering base 1, the first insulating cover 3 and the second insulating cover 4 are precisely aligned using guide positioning pins and positioning holes. This ensures the accurate size of the square clamping slot and avoids size deviations caused by misalignment of the two insulating covers. This prevents the pressure chip 5 from being clamped too loosely, too tightly, or tilted due to slot deviations, thus ensuring the positional accuracy of the chip assembly. Precise alignment also reduces adjustment time during subsequent installation of the pressure chip 5, improving the assembly efficiency of the clamping assembly. Simultaneously, the precise slot size ensures accurate contact between the elastic sheet 9 and the pressure chip 5, resulting in more uniform clamping force and reducing micro-deformation of the chip due to uneven force. This further improves the sensor's detection accuracy and reduces the product defect rate caused by assembly deviations.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions for some or all of the technical features, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A glue-free packaged silicon chip-sintered base snap-on type pressure sensor, comprising a sintered base (1), a pressure chip (5), an insulating cover and an electrical connection component, characterized in that, the insulating cover comprises a first insulating cover (3) and a second insulating cover (4), and the first insulating cover (3) and the second insulating cover (4) are spliced to form a square card slot inside for accommodating the pressure chip (5); at least one inner wall of the square card slot is provided with an elastic sheet (9), and the elastic sheet (9) is configured to elastically deform when the pressure chip (5) is inserted into the square card slot, thereby forming a flexible clamping and fixing of the pressure chip (5); the outer wall of the insulating cover is provided with a sealing groove, and an O-ring (6) is arranged in the sealing groove, and the insulating cover is fixed by the O-ring (6) and the inner wall of the mounting cavity of the sintered base (1) in the form of clamping fit.

2. The encapsulated silicon die-bonded pressure sensor of claim 1, wherein, The elastic sheet (9) is integrally formed with the first insulating cover (3) and / or the second insulating cover (4).

3. The no-glass package silicon die-sintered seat snap-type pressure sensor according to claim 2, wherein, The number of elastic sheets (9) is multiple, and they are distributed on the four corner parts of the upper side of the square card slot and the inner walls of the left and right sides.

4. The glue-free packaged silicon-sintered seat clamped type pressure sensor according to claim 1, wherein The spliced part of the first insulating cover (3) and the second insulating cover (4) is provided with a guide positioning pin and a positioning hole that cooperate with each other.

5. The encapsulated silicon die-bonded piezoresistive pressure sensor of claim 1, wherein, The size of the square card slot is a transition fit with the size of the pressure chip (5).

6. The package-free silicon die-burn-in board clamping type pressure sensor according to claim 1, wherein The insulating cover is made of alumina ceramic material.

7. The glue-free packaged silicon die-sintered seat snap-type pressure sensor according to claim 1, wherein, The electrical connection component includes a gold-plated kovar tube leg (10) fixed on the sintered base (1) by a glass sintering process, and the pressure chip (5) is connected by gold wire bonding with the gold-plated kovar tube leg (10).

8. The package-free silicon die-bonded seat clamped pressure sensor according to claim 1, wherein, It also includes a corrugated diaphragm (7) and a pressure ring (8) fixed on the sintered base (1), and an oil filling hole is formed on the sintered base (1), which is sealed by a welded steel ball (2), and the internal cavity of the sintered base (1) is filled with silicone oil (11).

9. A method of encapsulating a pressure sensor without glue, the method comprising: It includes the following steps: providing a first insulating cover (3) and a second insulating cover (4), and clamping a pressure chip (5) in a square card slot formed by splicing the first insulating cover (3) and the second insulating cover (4), and flexibly clamping the pressure chip (5) by the elastic sheet (9) arranged on the inner wall of the square card slot to form a clamping assembly; mounting the clamping assembly into the mounting cavity of the sintered base (1), and fixing the clamping assembly in the sintered base (1) by the clamping fit of the O-ring (6) arranged in the sealing groove of the outer wall of the insulating cover and the inner wall of the mounting cavity; realizing the electrical connection of the pressure chip (5) and the gold-plated kovar tube leg (10) fixed on the sintered base (1) by gold wire bonding process.

10. The method of encapsulating a pressure sensor without glue as claimed in claim 9, wherein, Before the clamping assembly is mounted, the guide positioning pin and the positioning hole at the spliced part of the first insulating cover (3) and the second insulating cover (4) are used for accurate positioning to limit the displacement of the pressure chip (5).

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