A stress isolation packaging structure of a MEMS chip and a packaging method thereof

Abstract

The present invention belongs to the field of semiconductor packaging technology, and discloses a stress isolation packaging structure of a MEMS chip and a packaging method thereof. This packaging structure includes a MEMS chip, a stress isolation plate, a packaging tube shell, leads, glue and a cover plate; the stress isolation plate structure includes a central bonding seat, a peripheral bonding seat, a peripheral bonding boss, a central bonding boss and an elastic beam; the "island" structure of the MEMS chip bonding seat designed by the present invention, the elastic beam structure, the bonding boss structure and the selection of the stress isolation plate material can effectively isolate the influence of patch stress and thermal stress, and has the characteristics of simple structure, easy implementation and strong versatility, and can be widely used in the integrated packaging of inertial sensor chips such as MEMS gyroscopes and accelerometers.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor packaging, and in particular relates to a stress isolation packaging structure of a MEMS chip and a packaging method thereof. Background Art

[0002] As a key technology for product manufacturing, MEMS inertial device packaging technology ultimately determines the product's volume, reliability and cost. The quality of processability is not only related to the performance of the device, but also directly affects the manufacturing cost of the device. Generally, the packaging and testing cost accounts for more than 50% of the entire product price. The main function of the packaging process is to realize the mechanical support, electrical connection, physical protection, external field shielding, stress relief, heat dissipation and moisture resistance, size transition, normalization and standardization of the device. In the packaging process, there will inevitably be mismatches in geometric shape, material composition and thermal expansion coefficient, leading to the generation of stress. Studies have shown that the shrinkage rate of general adhesives after curing is usually in the range of 0.15% to 0.6% of the volume. This shrinkage may produce large residual stress, which will change the resonant frequency of the MEMS inertial device and reduce its performance. Therefore, the control of packaging stress is a key issue that needs to be solved in the packaging process.

[0003] There are two types of stress isolation methods for MEMS sensors: active and passive. The active stress suppression method mainly reduces and isolates stress by optimizing the mechanical structure and processing technology, including specific solutions such as anchor layout optimization, bonding layout optimization, material selection, and optimized processing technology. The passive stress isolation method is to design a stress isolation structure to suppress stress transmission to the sensitive structure. The combination of active and passive stress isolation methods can effectively reduce the sensor temperature drift caused by thermal stress.

[0004] The present invention designs a stress isolation packaging structure for a MEMS chip, which belongs to a stress isolation method combining active and passive types, can effectively isolate the influence of patch stress and thermal stress, has the characteristics of small size, easy processing, low cost, etc., and can be widely used in the integrated packaging of inertial sensor chips such as MEMS gyroscopes and accelerometers. Summary of the invention

[0005] The technical problem to be solved by the present invention is as follows: In order to reduce the influence of packaging gravity and thermal stress generated in the MEMS chip packaging process, a stress isolation packaging structure of a MEMS chip and a packaging method thereof are provided. The stress isolation packaging structure of the MEMS chip has the characteristics of being simple, easy to implement, and highly versatile.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A stress isolation packaging structure of a MEMS chip, comprising a MEMS chip, a stress isolation plate, a packaging tube shell, leads, glue and a cover plate, wherein the packaging structure is, from top to bottom, a cover plate, a MEMS chip, a stress isolation plate, and a packaging tube shell, wherein the MEMS chip and the stress isolation plate and the stress isolation plate and the packaging tube shell are bonded by glue, and the MEMS chip is electrically connected to the pad of the packaging tube shell by leads; the stress isolation plate comprises a central bonding seat, a peripheral bonding seat, a peripheral bonding boss, a central bonding boss and an elastic beam; the stress isolation plate The overall structure presents central symmetry and axial symmetry, reducing the additional torsional stress caused by structural asymmetry. The central bonding seat and each peripheral bonding seat are structurally connected through two elastic beams, and different peripheral bonding seats are not in direct contact, presenting a relatively independent "island" structure; the central bonding seat and the peripheral bonding seat on the stress isolation plate are bonding areas, the position of the central bonding boss is set at the center of the central bonding seat structure, distributed along the stress transfer direction of the elastic beam, presenting a "cross shape"; the position of the peripheral bonding boss is set on the edge of the peripheral bonding seat, presenting an "L shape". One of the central bonding seat and the peripheral bonding seat is bonded to the packaging shell, and the other is bonded to the MEMS chip, so that the MEMS chip is "suspended" above the packaging shell, and the elastic beam isolates the stress transfer between the central bonding seat and the peripheral bonding seat.

[0008] Furthermore, the elastic beam is designed to be one of "I-shaped", "honeycomb-shaped", "X-shaped" and "S-shaped", and the thickness of the beam is not greater than the thickness of the stress isolation plate.

[0009] Furthermore, the stress isolation plate is made of a material having the same thermal expansion coefficient as that of the MEMS chip, or a material having a smaller difference in thermal expansion coefficient with that of the MEMS chip.

[0010] Furthermore, the stress isolation plate structure should be no smaller than the MEMS chip structure.

[0011] Furthermore, the present invention provides a method for packaging a stress isolation packaging structure of a MEMS chip, as follows:

[0012] S1. Material preparation: Prepare the materials required for packaging, including MEMS chip, stress isolation board, package tube shell, lead, glue and cover; the glue is selected from epoxy resin, eutectic solder and metal-doped glass adhesive; the lead is selected from gold wire and silver wire;

[0013] S2, first dispensing: dispensing glue at the designated position of the package shell;

[0014] S3, stress isolation plate bonding: the stress isolation plate is fixed to the package shell by glue, wherein the glue is applied to the package shell, and the coating thickness of the glue should be not less than the height of the central bonding boss, and then the central bonding seat on the stress isolation plate is bonded to the package shell by glue, and then the whole structure is heated to the curing temperature, and finally cooled to room temperature to complete the stress isolation plate bonding;

[0015] S4, second dispensing: dispensing glue at a designated position on the peripheral bonding seat of the stress isolation plate;

[0016] S5. MEMS chip mounting: fix the MEMS chip to the peripheral bonding seat of the stress isolation plate by glue, wherein the coating thickness of the glue should be no less than the height of the peripheral bonding boss, then heat the whole structure to the curing temperature, and finally cool to room temperature to complete the MEMS chip bonding;

[0017] S6. Wire bonding: Tightly weld the wires to the pads of the package shell, thereby achieving electrical interconnection between the MEMS chip and the package shell and information exchange between the chips;

[0018] S7, sealing and airtight welding: seal the cover plate to the packaging tube shell to complete the chip packaging.

[0019] Furthermore, the present invention provides a method for preparing a stress isolation plate of a stress isolation packaging structure of a MEMS chip, as follows:

[0020] S1. Material preparation: preparing a substrate for processing materials used as a stress isolation plate;

[0021] S2, photoresist coating: spin coating a layer of photoresist on the front side of the substrate, and baking and curing;

[0022] S3, photolithography: after photolithography development, drying is performed to etch out the peripheral bonding boss pattern;

[0023] S4, etching: using a wet etching method to etch a peripheral bonding boss structure on the substrate;

[0024] S5, degumming and cleaning: removing residual photoresist and cleaning;

[0025] S6, coating photoresist: spin coating a layer of photoresist on the front side of the substrate, and baking and curing;

[0026] S7, photolithography: after photolithography development and drying, a pattern of the main structure of the stress isolation plate is etched out;

[0027] S8, etching: using a wet etching method to etch the main structure of the stress isolation plate on the substrate, including a central bonding seat, a first peripheral bonding seat, a second peripheral bonding seat, a third peripheral bonding seat, a fourth peripheral bonding seat and an elastic beam;

[0028] S9, degumming and cleaning: removing residual photoresist and cleaning;

[0029] S10, substrate flipping and temporary bonding: flipping the substrate and bonding the substrate to the glass carrier;

[0030] S11, coating photoresist: spin coating a layer of photoresist on the front side of the substrate, and baking and curing;

[0031] S12, photolithography: after photolithography development, drying is performed to etch out a central bonding boss pattern;

[0032] S13, etching: using a wet etching method to etch a structure of a central bonding boss on the substrate;

[0033] S14, degumming and cleaning: removing residual photoresist and cleaning;

[0034] S15. Laser debonding and cleaning: Use laser technology to separate the bonded structures and then clean the structures.

[0035] Beneficial Effects

[0036] Through the above scheme, the beneficial effects obtained by the present invention are as follows: the packaging structure adopts a passive stress isolation method to isolate the influence of patch stress and thermal stress. The core structure of its stress isolation lies in the design of a stress isolation plate between the MEMS chip and the packaging shell. The stress isolation plate consists of five parts: a central bonding seat, a peripheral bonding seat, a peripheral bonding boss, a central bonding boss and an elastic beam. The scheme can isolate stress from the following technologies:

[0037] First, different MEMS chip bonding seats are not in direct contact with each other, presenting a relatively independent "island" structure. The "island" structure is conducive to reducing stress transfer between different MEMS chip bonding seats.

[0038] Secondly, the elastic beam can effectively isolate the stress of the patch through the deformation of the beam itself, and the small cross-sectional area of ​​the beam is conducive to reducing the temperature changes of the MEMS chip caused by heat conduction due to changes in the external ambient temperature, thereby reducing the thermal stress of the MEMS chip.

[0039] Furthermore, the outer bonding boss and the central bonding boss simultaneously play the role of "structural reinforcement" and glue control, thereby improving the structural strength and reducing deformation.

[0040] Finally, the stress isolation plate structure uses a material with the same thermal expansion coefficient as the MEMS chip, or a material with a smaller difference in thermal expansion coefficient from the MEMS chip, such as a single crystal silicon wafer, glass or metal material, to further reduce the difference in thermal expansion coefficient between the packaging tube shell and the chip, thereby reducing the packaging stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a cross-sectional view of a stress isolation packaging structure of a MEMS chip proposed by the present invention, and the packaging structure is suitable for ceramic packaging of a MEMS chip;

[0042] Figure 2 A structural diagram of a stress isolation plate of a stress isolation packaging structure of a MEMS chip proposed by the present invention. Figure 2 (a) is the axonometric view of the stress isolation plate. Figure 2 (b) is the front view of the stress isolation plate. Figure 2 (c) is the back view of the stress isolation plate;

[0043] Figure 3 A schematic diagram of a packaging process of a stress isolation packaging structure of a MEMS chip proposed by the present invention, which is applicable to ceramic packaging;

[0044] Figure 4 A schematic diagram of a process flow for preparing a stress isolation plate of a stress isolation packaging structure of a MEMS chip proposed by the present invention;

[0045] Figure 5 A cross-sectional view of a plastic package of a stress isolation package structure of a MEMS chip proposed by the present invention;

[0046] Figure 6 This is a schematic diagram of a plastic packaging process for a stress isolation packaging structure of a MEMS chip proposed by the present invention.

[0047] Figure 1 Middle: 1-package shell, 2-lead, 3-MEMS chip, 4-stress isolation board, 5-glue and 6-cover.

[0048] Figure 2 In the middle: 4a-central bonding seat, 4b-peripheral bonding seat, 4c-peripheral bonding boss, 4d-central bonding boss, 4e-elastic beam, 4b1-first peripheral bonding seat, 4b2-second peripheral bonding seat, 4b3-third peripheral bonding seat and 4b4-fourth peripheral bonding seat.

[0049] Figure 4 Middle: 3a - substrate, 3b - photoresist and 3c - glass carrier.

[0050] Figure 5 Middle: 7-package carrier, 2-leads, 3-MEMS chip, 4-stress isolation board, 5-glue and 8-plastic packaging material. DETAILED DESCRIPTION

[0051] The following is a clear and complete description of the technical solutions in the embodiments of the present invention through specific examples and drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0052] In addition, the words “first”, “second” and the like used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts.

[0053] Specific embodiment 1: This embodiment is for MEMS chip ceramic shell packaging, see attached Figure 1 The stress isolation packaging structure of the MEMS chip includes a packaging tube shell 1, a lead 2, a MEMS chip 3, a stress isolation plate 4, glue 5 and a cover plate 6. Among them, by adding the structure of the stress isolation plate 4 of the "isolated island" structure, the MEMS chip 3 is "suspended" above the packaging tube shell 1. This structural form can effectively isolate stress. In this embodiment, a packaging method of this structure is also provided. See the attached Figure 3 , including the following steps:

[0054] S1. Material preparation: prepare the materials required for packaging, including MEMS chip 3, stress isolation plate 4, packaging tube shell 1, lead 2, glue 5 and cover 6; glue 5 is epoxy resin; lead 2 is gold wire;

[0055] S2, first dispensing: dispensing glue at the specified position of the package shell 1;

[0056] S3, bonding of stress isolation plate 4: fix the stress isolation plate 4 on the package tube shell 1 by glue 5, wherein the glue 5 is applied on the package tube shell 1, and the coating thickness of the glue should be not less than the height of the central bonding boss 4d, then bond the central bonding seat 4a on the stress isolation plate 4 to the package tube shell 1 by glue 5, then heat the whole structure to the curing temperature, and finally cool to room temperature to complete the bonding of the stress isolation plate 4;

[0057] S4, second glue dispensing: dispensing glue at a designated position on the peripheral bonding seat 4b of the stress isolation plate 4;

[0058] S5, mounting the MEMS chip 3: fix the MEMS chip 3 on the peripheral bonding seat 4b of the stress isolation plate 4 by glue 5, wherein the coating thickness of the glue should be not less than the height of the peripheral bonding boss 4c, then heat the whole structure to the curing temperature, and finally cool to room temperature to complete the bonding of the MEMS chip 3;

[0059] S6, wire 2 bonding: tightly welding the wire 2 to the pad of the package tube shell 1, so as to realize electrical interconnection between the MEMS chip 3 and the package tube shell 1 and information exchange between the chips;

[0060] S7, sealing and airtight welding: sealing and welding the cover plate 6 to the packaging tube shell 1 to complete the chip packaging.

[0061] In addition, the above packaging steps are applicable to a packaging method in which the MEMS chip 3 is bonded to the peripheral bonding boss 4c on the stress isolation plate 4 structure. If the MEMS chip 3 is bonded to the central bonding boss 4d on the stress isolation plate 4 structure, the corresponding packaging can be achieved by simply adjusting the corresponding glue dispensing sequence and adjusting the bonding position of the stress isolation plate 4. In addition to epoxy resin, the glue 5 in this embodiment can also be selected from eutectic solder and metal-doped glass adhesive. In addition to gold wire, the lead 2 can also be selected from silver wire.

[0062] See attached Figure 2 The structure of the stress isolation plate 4 includes a central bonding seat 4a, a peripheral bonding seat 4b, a peripheral bonding boss 4c, a central bonding boss 4d and an elastic beam 4e. The central bonding seat 4a and the peripheral bonding seat 4b are structurally connected by the elastic beam 4e, and different peripheral bonding seats 4b are not in direct contact with each other, presenting a relatively independent "island" structure; the central bonding boss 4d of the structure is located at the center of the central bonding seat 4a structure, and is distributed along the stress transfer direction of the elastic beam 4e, presenting a "cross shape". The position of the peripheral bonding boss 4c is set on the edge of the peripheral bonding seat 4b, and is "L-shaped". The boss structure can play the role of "structural reinforcement ribs" and glue control; the elastic beam 4e of the structure is designed to be "J-shaped", and the thickness of the beam is not greater than the thickness of the stress isolation plate 4; in order to reduce the additional torsional stress caused by structural asymmetry, the overall structure of the stress isolation plate 4 is designed to be centrally symmetrical and axially symmetrical; in view of the different thermal expansion coefficients of different materials, the glue 5 will generate greater stress after curing, so the stress isolation plate 4 is processed with a single crystal silicon wafer material with a thermal expansion coefficient similar to that of the MEMS chip 3; considering the convenience of installation, the size of the stress isolation plate 4 is consistent with the size of the MEMS chip 3.

[0063] In this embodiment, a preparation process of a stress isolation plate 4 is also provided. Figure 4 ,include:

[0064] S1. Material preparation: preparing a substrate 3a used as a processing material for the stress isolation plate 4, wherein the processing material is a material having a smaller difference in thermal expansion coefficient with the MEMS chip 3, such as a single crystal silicon wafer;

[0065] S2, coating photoresist 3b: spin coating a layer of photoresist 3b on the front surface of substrate 3a, and baking and curing;

[0066] S3, photolithography: after photolithography development and drying, the peripheral bonding boss 4c pattern is etched out;

[0067] S4, etching: using a wet etching method, etching the structure of the peripheral bonding boss 4c on the substrate 3a;

[0068] S5, debonding and cleaning: removing the residual photoresist 3b and cleaning;

[0069] S6, coating photoresist 3b: spin coating a layer of photoresist 3b on the front surface of substrate 3a, and baking and curing;

[0070] S7, photolithography: after photolithography development and drying, etching out the pattern of the main structure of the stress isolation plate 4;

[0071] S8, etching: using a wet etching method, etching the main structure of the stress isolation plate 4 on the substrate 3a, including the central bonding seat 4a, the first peripheral bonding seat 4b1, the second peripheral bonding seat 4b2, the third peripheral bonding seat 4b3, the fourth peripheral bonding seat 4b4 and the elastic beam 4e;

[0072] S9, debonding and cleaning: removing the residual photoresist 3b and cleaning;

[0073] S10, turning over and temporarily bonding the substrate 3a: turning over the substrate 3a, and bonding the substrate 3a to the glass carrier 3c;

[0074] S11, coating photoresist 3b: spin coating a layer of photoresist 3b on the front surface of substrate 3a, and baking and curing;

[0075] S12, photolithography: after photolithography development, drying is performed to etch out the center bonding boss 4d pattern;

[0076] S13, etching: using a wet etching method, etching a structure of a central bonding boss 4d on the substrate 3a;

[0077] S14, debonding and cleaning: removing the residual photoresist 3b and cleaning;

[0078] S15. Laser debonding and cleaning: Use laser technology to separate the bonded structures and then clean the structures.

[0079] In this embodiment, the elastic beam 4e can be designed into a "J-shape" or a "S-shape", a "honeycomb shape" or a "S-shape" in addition to being designed into a "J-shape". In this embodiment, the material of the stress isolation plate 4 can be made of glass or metal materials in addition to single crystal silicon wafers.

[0080] The following further describes other applicable situations of the present invention through another embodiment.

[0081] Specific embodiment 2: In addition to the above-mentioned MEMS chip ceramic packaging, the structure of the present invention is also applicable to MEMS chip plastic packaging, see attached Figure 5 The stress isolation packaging structure of the MEMS chip includes a packaging carrier 7, a lead 2, a MEMS chip 3, a stress isolation plate 4, glue 5 and a plastic packaging material 8. The packaging method of the structure is shown in the attached Figure 6 , including the following steps:

[0082] S1. Material preparation: prepare the materials required for packaging, including packaging carrier 7, lead 2, MEMS chip 3, stress isolation plate 4, glue 5 and plastic packaging material 8;

[0083] S2, first dispensing: dispensing glue at a designated position of the packaging carrier 7;

[0084] S3, bonding of stress isolation plate 4: fix the stress isolation plate 4 on the packaging carrier 7 by glue 5, wherein the glue 5 is applied on the packaging carrier 7, and the coating thickness of the glue should be not less than the height of the central bonding boss 4d, then bond the central bonding seat 4a on the stress isolation plate 4 to the packaging carrier 7 by glue 5, then heat the whole structure to the curing temperature, and finally cool to room temperature to complete the bonding of the stress isolation plate 4;

[0085] S4, second glue dispensing: dispensing glue at a designated position on the peripheral bonding seat 4b of the stress isolation plate 4;

[0086] S5, mounting the MEMS chip 3: fix the MEMS chip 3 on the peripheral bonding seat 4b of the stress isolation plate 4 by glue 5, wherein the coating thickness of the glue should be not less than the height of the peripheral bonding boss 4c, then heat the whole structure to the curing temperature, and finally cool to room temperature to complete the bonding of the MEMS chip 3;

[0087] S6, wire 2 bonding: tightly welding the wire 2 to the pad of the package carrier 7, so as to realize electrical interconnection between the MEMS chip 3 and the information exchange between the chips;

[0088] S7, plastic packaging: the plastic packaging material 8 is poured and die-cast onto the packaging carrier 7 through the plastic packaging die system to complete the chip plastic packaging.

[0089] In summary, the two embodiments described in the present invention can both effectively isolate stress, and the principle of stress isolation is the same: by setting a stress isolation plate 4 in the packaging structure, when the MEMS chip 3 is subjected to the stress generated by the packaging, the stress isolation plate 4 reduces the interference stress through its own deformation; furthermore, the peripheral bonding boss 4c and the central bonding boss 4d on the stress isolation plate 4 structure simultaneously play the role of "structural reinforcement ribs" and glue control, thereby improving the structural strength and reducing deformation; finally, through the material selection of the stress isolation plate 4 structure, the difference in thermal expansion coefficient between the packaging tube shell 1 / packaging carrier 7 and the MEMS chip 3 is further reduced, thereby reducing the packaging stress.

[0090] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A stress isolation packaging structure for a MEMS chip, characterized in that: The packaging structure comprises a MEMS chip (3), a stress isolation plate (4), a packaging tube shell (1), leads (2), glue (5) and a cover plate (6), wherein the packaging structure comprises, from top to bottom, a cover plate (6), a MEMS chip (3), a stress isolation plate (4) and a packaging tube shell (1), wherein the MEMS chip (3) and the stress isolation plate (4) as well as the stress isolation plate (4) and the packaging tube shell (1) are bonded by means of glue (5), and the MEMS chip (3) is electrically connected to the pad of the packaging tube shell (1) by means of leads (2); the stress isolation plate (4) comprises a central bonding seat (4a), a peripheral bonding seat (4b), a peripheral bonding boss (4c), a central bonding boss (4d) and an elastic beam (4e); the overall structure of the stress isolation plate (4) is centrally symmetrical and axially symmetrical, thereby reducing the additional torsional stress generated by the asymmetric structure; the central bonding seat (4a) and each The peripheral bonding seats (4b) are structurally connected via two elastic beams (4e), and different peripheral bonding seats (4b) are not in direct contact with each other, presenting a relatively independent "isolated island" structure; the central bonding seat (4a) and the peripheral bonding seat (4b) on the stress isolation plate (4) are bonding areas; the central bonding boss (4d) is arranged at the center of the central bonding seat (4a) structure and is distributed along the stress transmission direction of the elastic beam (4e) in a "cross shape"; the peripheral bonding boss (4c) is arranged at the edge of the peripheral bonding seat (4b) in an "L shape"; one of the central bonding seat (4a) and the peripheral bonding seat (4b) is bonded to the packaging tube shell (1), and the other is bonded to the MEMS chip (3), so that the MEMS chip (3) is "suspended" above the packaging tube shell (1); the elastic beam (4e) isolates the stress transmission between the central bonding seat (4a) and the peripheral bonding seat (4b).

2. A stress isolation packaging structure for a MEMS chip as claimed in claim 1, characterized in that: The elastic beam (4e) is designed to be one of a "straight-shaped", "honeycomb-shaped", "X-shaped" and "S-shaped", and the thickness of the beam is not greater than the thickness of the stress isolation plate (4).

3. The stress isolation packaging structure of a MEMS chip as claimed in claim 1, characterized in that: The stress isolation plate (4) is made of a material having the same thermal expansion coefficient as that of the MEMS chip (3), or a material having a smaller difference in thermal expansion coefficient with that of the MEMS chip (3).

4. The stress isolation packaging structure of a MEMS chip according to claim 1, characterized in that: The structure of the stress isolation plate (4) should be no smaller than the structure of the MEMS chip (3).

5. The stress isolation packaging structure of a MEMS chip as claimed in claim 1, wherein the packaging method is as follows: S1. Material preparation: preparing materials required for packaging, including MEMS chip (3), stress isolation plate (4), packaging tube shell (1), lead wire (2), glue (5) and cover plate (6); the glue (5) is selected from epoxy resin, eutectic solder or metal-doped glass adhesive; the lead wire (2) is selected from gold wire and silver wire; S2, first dispensing: dispensing glue at a designated position of the packaging tube shell (1); S3, bonding of the stress isolation plate (4): the stress isolation plate (4) is fixed to the packaging tube shell (1) by means of glue (5), wherein the glue (5) is applied to the packaging tube shell (1), and the coating thickness of the glue should be no less than the height of the central bonding boss (4d), and then the central bonding seat (4a) on the stress isolation plate (4) is bonded to the packaging tube shell (1) by means of glue (5), and then the whole structure is heated to the curing temperature, and finally cooled to room temperature to complete the bonding of the stress isolation plate (4); S4, second glue dispensing: dispensing glue at a designated position on the peripheral bonding seat (4b) of the stress isolation plate (4); S5, mounting of the MEMS chip (3): fixing the MEMS chip (3) on the peripheral bonding seat (4b) of the stress isolation plate (4) by means of glue (5), wherein the coating thickness of the glue should be no less than the height of the peripheral bonding boss (4c), then heating the whole structure to the curing temperature, and finally cooling to room temperature to complete the bonding of the MEMS chip (3); S6, wire (2) bonding: tightly welding the wire (2) to the pad of the package tube shell (1), thereby achieving electrical interconnection between the MEMS chip (3) and the package tube shell (1) and information exchange between the chips; S7, sealing and airtight welding: sealing and welding the cover plate (6) to the packaging tube shell (1) to complete the chip packaging.

6. A stress isolation packaging structure for a MEMS chip as claimed in claim 2, wherein the stress isolation plate (4) is prepared as follows: S1. Material preparation: preparing a substrate (3a) for use as a processing material for a stress isolation plate (4); S2, coating photoresist (3b): spin coating a layer of photoresist (3b) on the front surface of the substrate (3a), and baking and curing; S3, photolithography: after photolithography development and drying, the peripheral bonding boss (4c) pattern is etched out; S4, etching: using a wet etching method to etch a structure of a peripheral bonding boss (4c) on the substrate (3a); S5, photoresist removal and cleaning: removing residual photoresist (3b) and cleaning; S6, coating photoresist (3b): spin coating a layer of photoresist (3b) on the front surface of the substrate (3a), and baking and curing; S7, photolithography: after photolithography development and drying, etching out the pattern of the main structure of the stress isolation plate (4); S8, etching: using a wet etching method to etch the main structure of the stress isolation plate (4) on the substrate (3a), including a central bonding seat (4a), a first peripheral bonding seat (4b1), a second peripheral bonding seat (4b2), a third peripheral bonding seat (4b3), a fourth peripheral bonding seat (4b4) and an elastic beam (4e); S9, photoresist removal and cleaning: removing residual photoresist (3b) and cleaning; S10, turning over and temporarily bonding the substrate (3a): turning over the substrate (3a), and bonding the substrate (3a) to the glass carrier (3c); S11, coating photoresist (3b): spin coating a layer of photoresist (3b) on the front surface of the substrate (3a), and baking and curing; S12, photolithography: after photolithography development, drying is performed to etch out the pattern of the central bonding boss (4d); S13, etching: using a wet etching method to etch a structure of a central bonding boss (4d) on the substrate (3a); S14, photoresist removal and cleaning: removing residual photoresist (3b) and cleaning; S15. Laser debonding and cleaning: Use laser technology to separate the bonded structures and then clean the structures.

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