A MEMS chip bonding structure and a MEMS inertial device

Abstract

This invention provides a MEMS chip bonding structure and a MEMS inertial device, belonging to the field of sensor technology. The MEMS chip bonding structure is used to connect a packaged housing and a chip, and includes a connector and multiple positioning parts. The connector includes a first connecting part, a second connecting part, and a third connecting part. The first connecting part is used to bond to the packaged housing, the third connecting part is used to bond to the chip, and the second connecting part is located between the first connecting part and the third connecting part to isolate the stress transmitted from the packaged housing to the chip. The connector and each positioning part have a first mating state and a second mating state. In the first mating state, the positioning parts of the MEMS chip bonding structure provided by this invention abut against the third connecting part, providing temporary rigid support for the chip bonding process. In the second mating state, the positioning parts avoid the third connecting part, allowing the second connecting part to restore its stress isolation function, thereby balancing bonding quality and device operational stability.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, and more specifically, relates to a MEMS chip bonding structure and a MEMS inertial device, particularly to a MEMS chip bonding structure that can provide rigid support during chip bonding, and a MEMS inertial device using the MEMS chip bonding structure. Background Technology

[0002] MEMS inertial devices, such as gyroscopes, accelerometers, and resonators, are highly sensitive to mechanical stress. Stress can alter the stiffness and resonant frequency of their sensitive structures, inducing unintended coupling between the sensitive structures and external or thermal stresses, thereby affecting the stability of MEMS inertial devices. External stresses often originate from deformation caused by mechanical vibrations and impacts; these stresses, when transmitted to the chip, can cause problems such as zero-point drift and scaling changes.

[0003] To isolate stress, existing technologies add a flexible platform between the MEMS chip and the underlying structure formed by the packaging shell. The flexible platform is suspended above the underlying structure by multiple support beams. When external stress is applied, the flexible platform absorbs or buffers the stress through the elastic deformation of the support beams, thereby protecting the chip body from direct impact and achieving effective stress isolation.

[0004] However, when bonding MEMS chips to a flexible platform, the flexible platform cannot effectively withstand the necessary compressive force, and is prone to deformation or displacement, making it difficult to form a uniform and firm bonding interface with the MEMS chip, thus affecting the bonding quality and the actual application effect of the stress isolation structure. Summary of the Invention

[0005] The purpose of this invention is to provide a MEMS chip bonding structure and a MEMS inertial device, which aims to solve the problem that the flexible platform cannot effectively withstand the pressure during the existing MEMS chip bonding process, resulting in poor bonding effect.

[0006] This invention provides a MEMS chip bonding structure for connecting a packaged housing and a chip. The invention also provides a MEMS inertial device employing this MEMS chip bonding structure. This MEMS chip bonding structure separates the temporary rigid support function during chip bonding from the flexible stress isolation function during the finished product operation stage by having the connector in a first mating state and a second mating state relative to the positioning part. In the first mating state, the positioning part directly supports the third connecting part, so that the chip bonding pressure does not primarily act on the second connecting part; in the second mating state, the positioning part separates from the third connecting part and forms a clearance gap, the first connecting part is bonded and fixed to the packaged housing, and the second connecting part can isolate the stress transmitted from the packaged housing to the chip through elastic deformation.

[0007] In a first aspect, a MEMS chip bonding structure is provided for connecting a package and a chip, including: The connector includes a first connecting portion, a second connecting portion, and a third connecting portion; the first connecting portion is used to bond with the package housing, the third connecting portion is used to bond with the chip, and the second connecting portion is located between the first connecting portion and the third connecting portion to isolate the stress transmitted from the package housing to the chip; Multiple positioning parts are fixedly disposed on the encapsulation tube shell and arranged around it to form a positioning area that matches the outer contour of the first connecting part. The connector and each of the positioning parts have a first mating state and a second mating state; In the first mating state, the first connecting part is embedded in the positioning area, and the top of each positioning part abuts against the bottom surface of the third connecting part, so as to provide temporary rigid support for the third connecting part during the bonding process between the chip and the third connecting part. In the second mating state, the first connecting part is released from the positioning area, each positioning part avoids the third connecting part, and the first connecting part is bonded to the encapsulation shell.

[0008] In one possible implementation, the first connecting part is provided with a plurality of positioning holes for the positioning part to pass through, and the positioning holes correspond one-to-one with the positioning part; In the first mating state, each of the positioning parts is separated from the corresponding positioning hole; In the second mating state, each of the positioning parts is inserted into the corresponding positioning hole to position the first connecting part.

[0009] In one possible implementation, the first connecting portion has a plurality of venting grooves on the side facing the encapsulation shell, and the venting grooves correspond one-to-one with the positioning holes and are interconnected. In the second mating state, during the bonding process between the first connecting part and the encapsulation shell, the air between the first connecting part and the encapsulation shell is discharged along the venting groove to the positioning hole, so that the adhesive fills the gap between the first connecting part and the encapsulation shell.

[0010] In one possible implementation, the plurality of exhaust slots are arranged radially, and the ends of each exhaust slot opposite to the corresponding positioning hole are interconnected.

[0011] In one possible implementation, each of the positioning parts has a step; In the second mating state, the bottom surface of the first connecting part abuts against the top surface of each of the steps to form an adhesive gap between the first connecting part and the encapsulation shell. The adhesive gap is used to accommodate adhesive and control the thickness of the adhesive layer.

[0012] In one possible implementation, each of the steps forms a positioning surface on its side, and the multiple positioning surfaces together enclose the positioning area; In the first mating state, each of the positioning surfaces fits against the outer contour of the first connecting part to limit the position of the first connecting part.

[0013] In one possible implementation, the third connection portion includes: The central island is fixedly connected to the second connecting part; Multiple peripheral islands are arranged around the central island for bonding with the chip; each peripheral island is connected to the central island by a connecting beam. Each of the connecting beams has an elastic degree of freedom to isolate the stress transmitted from the central island to the outer island; The outer islands correspond one-to-one with the positioning parts. In the first engagement state, the bottom surface of each outer island abuts against the top surface of the corresponding positioning part. In the second engagement state, each positioning part avoids the corresponding outer island.

[0014] In one possible implementation, the bottom surface of each of the peripheral islands is fixed with a reinforcing rib, and the top of each of the positioning parts is provided with a limiting groove suitable for fitting the reinforcing rib. In the first mating state, each of the reinforcing ribs is fitted into the corresponding limiting groove to limit the peripheral island; in the second mating state, each of the reinforcing ribs is separated from the corresponding limiting groove.

[0015] In one possible implementation, the second connection includes a plurality of connecting posts, each of which has a different cross-sectional area and / or cross-sectional shape.

[0016] The MEMS chip bonding structure provided by this invention has the following advantages compared with the prior art: During the bonding process between the chip and the third connecting part, the connector is in a first mating state. The first connecting part is embedded within a positioning area formed by multiple positioning parts. The positioning parts horizontally limit the first connecting part, preventing lateral displacement or torsion of the connector during the bonding and pressing process. Simultaneously, the tops of each positioning part rigidly abut against the bottom surface of the third connecting part, allowing the chip bonding pressure to be transmitted to the package shell via the third connecting part and the positioning parts, rather than forming the main load-bearing path through the second connecting part. This avoids unexpected deformation of the second and third connecting parts due to the pressure, ensuring that the third connecting part maintains a stable height position and a flat bonding surface during the bonding stage.

[0017] After the chip and the third connecting part are bonded together, the connector switches to the second mating state. The first connecting part is bonded and fixed to the package shell, and each positioning part separates from the third connecting part, forming a clearance gap. This removes the restriction imposed by the positioning parts on the elastic deformation space of the third and second connecting parts. At this time, the vibration, impact, or thermal deformation stress generated by the package shell is transmitted to the second connecting part through the first connecting part, and then buffered and attenuated by the elastic deformation of the second connecting part, reducing the stress from being transmitted to the third connecting part and the chip.

[0018] Therefore, this invention does not improve bonding quality by permanently increasing the stiffness of the flexible platform, nor does it simply reduce the stiffness of the connection structure to enhance stress isolation capability. Instead, it utilizes the positioning part to provide temporary rigid support during the chip bonding stage, and removes the support and restores the flexible isolation path during the device operation stage, thereby taking into account the feasibility of the packaging process, the reliability of the bonding interface, and the stability of MEMS chip operation.

[0019] Secondly, a MEMS inertial device is provided, comprising any of the aforementioned MEMS chip bonding structures.

[0020] The present invention provides a MEMS inertial device that, by adopting the above-mentioned MEMS chip bonding structure, can provide temporary rigid support by the positioning part during the chip bonding process to ensure the firmness and alignment accuracy of the bonding interface; in the working state, the positioning part is separated from the third connecting part, and the second connecting part achieves stress isolation, thereby reducing the impact of vibration, impact or thermal deformation stress transmitted by the package shell on the chip, and improving the stability, structural reliability and service life of the MEMS inertial device. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art 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.

[0022] Figure 1 This is a schematic diagram of the structure of the connector provided in an embodiment of the present invention; Figure 2 This is another structural schematic diagram of the connector provided in an embodiment of the present invention; Figure 3 A cross-sectional view of the packaged casing, chip, and connector in a first mating state provided in an embodiment of the present invention; Figure 4 Another cross-sectional view of the packaged casing, chip, and connector in the first mating state provided in an embodiment of the present invention; Figure 5 A cross-sectional view of the packaged casing, chip, and connector in the second mating state provided in an embodiment of the present invention; Figure 6 Another cross-sectional view of the packaged casing, chip, and connector in the second mating state provided in an embodiment of the present invention; Figure 7 for Figure 4 A magnified structural diagram of part A in the middle.

[0023] In the diagram: 1. Encapsulation housing; 2. Chip; 3. Connector; 31. First connecting part; 311. Positioning hole; 312. Exhaust groove; 32. Second connecting part; 321. Connecting post; 33. Third connecting part; 331. Central island; 332. Peripheral island; 333. Connecting beam; 334. Reinforcing rib; 4. Positioning part; 41. Step; 411. Positioning surface; 42. Limiting groove. Detailed Implementation

[0024] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0025] Please see Figure 1 , Figure 2 and Figure 3The present invention provides a MEMS chip bonding structure. The MEMS chip bonding structure, used to connect a package housing 1 and a chip 2, includes a connector 3 and multiple positioning portions 4. The connector 3 includes a first connecting portion 31, a second connecting portion 32, and a third connecting portion 33. The first connecting portion 31 is used to bond to the package housing 1, the third connecting portion 33 is used to bond to the chip 2, and the second connecting portion 32 is located between the first connecting portion 31 and the third connecting portion 33. The second connecting portion 32 has elastic deformation capability to isolate stress transmitted from the package housing 1 to the chip 2. Multiple positioning portions 4 are fixedly disposed on the package housing 1 and arranged around it to form a positioning area adapted to the outer contour of the first connecting portion 31.

[0026] Please see Figure 4 , Figure 5 and Figure 6 The connector 3 and each positioning part 4 have a first mating state and a second mating state. In the first mating state, the first connector 31 is embedded in the positioning area, and the top of each positioning part 4 abuts against the bottom surface of the third connector 33 to provide temporary rigid support for the third connector 33 during the bonding process between the chip 2 and the third connector 33. In the second mating state, the first connector 31 is released from the positioning area, each positioning part 4 avoids the third connector 33, and the first connector 31 is bonded to the packaging shell 1.

[0027] For example, the material of connector 3 is a material with the same or similar coefficient of thermal expansion as silicon, specifically, it can be a monocrystalline silicon wafer, polycrystalline silicon, or low-expansion glass.

[0028] For example, the adhesive may be epoxy resin, eutectic solder, or metal-doped glass adhesive.

[0029] During the bonding process of chip 2, the connector 3 and each positioning part 4 are in a first mating state. At this time, the first connector 31 is embedded in the positioning area surrounded by multiple surrounding positioning parts 4. The top of each positioning part 4 abuts against the bottom surface of the third connector 33, so that the positioning part 4 acts as a temporary rigid support and directly bears the pressing force from the bonding of chip 2, and transmits the force to the package shell 1. As a result, the bonding pressing force will not mainly act on the second connector 32. The second connector 32 does not need to bear the main pressing load during the bonding process, thereby avoiding the second connector 32 from unexpected deflection, buckling or torsion, and keeping the third connector 33 at a preset height position and horizontal posture, providing a flat and stable bonding reference surface for chip 2.

[0030] After the chip 2 is bonded and the adhesive has cured, the connector 3 switches to the second mating state. The first connecting part 31 is bonded and fixed to the package shell 1, and the limiting relationship between the first connecting part 31 and the outer contour of the positioning area is released. Each positioning part 4 no longer contacts the third connecting part 33, but forms a clearance gap with the third connecting part 33. This clearance gap is used to release the elastic deformation space of the second connecting part 32 and the third connecting part 33, and to prevent the positioning part 4 from forming a rigid short circuit path during the device operation stage. When external stress is transmitted through the package shell 1, the stress first acts on the first connecting part 31, and then is transmitted to the third connecting part 33 and the chip 2 through the second connecting part 32. Since the second connecting part 32 has elastic deformation capability, it can absorb or buffer the main part of the stress, realizing stress isolation between the package shell 1 and the chip 2.

[0031] In some possible embodiments, please refer to Figure 1 , Figure 4 and Figure 6 The first connecting portion 31 has multiple positioning holes 311 through which the positioning portions 4 pass, and each positioning hole 311 corresponds to a positioning portion 4. In the first mating state, each positioning portion 4 is separated from its corresponding positioning hole 311. In the second mating state, each positioning portion 4 is inserted into its corresponding positioning hole 311 to position the first connecting portion 31.

[0032] After chip 2 is bonded and the adhesive has cured, connector 3 needs to be bonded to the package housing 1, and the abutment relationship between positioning part 4 and third connecting part 33 needs to be released, so that the structure switches to the second mating state. During the switching process, each positioning part 4 enters the corresponding positioning hole 311, and a sliding guide relationship is formed between the side wall of positioning part 4 and the inner wall of positioning hole 311, thereby constraining the translational and rotational degrees of freedom of the first connecting part 31 in the horizontal direction and guiding the first connecting part 31 to descend in the vertical direction. At the same time, the top of each positioning part 4 separates from the bottom surface of the third connecting part 33, so that the positioning part 4 no longer supports the third connecting part 33, thereby avoiding the positioning part 4 from affecting the elastic deformation of the second connecting part 32 and the third connecting part 33 during the working stage.

[0033] When the structure enters the second mating state and the bonding and fixing process between the first connecting part 31 and the encapsulation shell 1 is carried out, each positioning part 4 is always inserted into the corresponding positioning hole 311, forming a continuous hole position constraint on the first connecting part 31. During the flow stage before the adhesive cures, this hole position constraint can resist the thrust generated by the flow of adhesive and external micro-disturbances, preventing the first connecting part 31 from drifting and ensuring the relative position of the connecting part 3 and the encapsulation shell 1. At the same time, each positioning part 4 maintains a clearance gap with the third connecting part 33, so that a bypass rigid force transmission path is not formed from the encapsulation shell 1 directly to the third connecting part 33 via the positioning part 4.

[0034] In some possible embodiments, the diameter of the positioning hole 311 may be larger than the outer diameter of the corresponding positioning part 4, so as to reserve an assembly gap between the positioning part 4 and the first connecting part 31 in the second mating state, thereby reducing the additional stress caused by assembly errors or thermal deformation.

[0035] In some possible embodiments, please refer to Figure 1 and Figure 2 The first connecting part 31 has multiple venting grooves 312 on the side facing the encapsulation shell 1. The venting grooves 312 correspond one-to-one with the positioning holes 311 and are interconnected. In the second mating state, during the bonding process between the first connecting part 31 and the encapsulation shell 1, the air between the first connecting part 31 and the encapsulation shell 1 is discharged along the venting grooves 312 to the positioning holes 311, so that the adhesive fills the gap between the first connecting part 31 and the encapsulation shell 1.

[0036] When bonding the first connecting part 31 to the encapsulation shell 1 in the second mating state, as the pressing force is gradually applied, the first connecting part 31 gradually moves closer to the encapsulation shell 1. The adhesive between the two is squeezed and spreads outwards. The air between the first connecting part 31 and the encapsulation shell 1 will diffuse outwards under pressure. Since the exhaust groove 312 and the positioning hole 311 are interconnected, the pressurized air can flow directionally along the channel of the exhaust groove 312 and flow into the positioning hole 311. Finally, it is discharged outwards through the upper opening of the positioning hole 311, avoiding the formation of air bubbles in the bonding interface.

[0037] Preferably, in the second mating state, the clearance between the top of the positioning part 4 and the bottom surface of the third connecting part 33 is greater than the maximum elastic deformation of the second connecting part 32 under a predetermined working stress, or greater than the maximum displacement of the third connecting part 33 under a predetermined working stress. With this arrangement, even if the encapsulated shell 1 deforms due to vibration, impact, or temperature changes, the positioning part 4 will not re-contact the third connecting part 33, thereby preventing the positioning part 4 from forming a bypass rigid force transmission path and ensuring the continued effectiveness of the stress isolation function of the second connecting part 32.

[0038] The expulsion of air allows the adhesive to fully fill the bonding area between the first connection portion 31 and the encapsulation shell 1, forming a bubble-free, continuous, and uniform adhesive layer. This ensures that stress is evenly distributed along the entire interface when transmitted from the encapsulation shell 1 to the first connection portion 31, preventing localized stress concentration from interfering with the stress isolation effect of the second connection portion 32. The positioning hole 311 serves both positioning and venting functions, effectively improving the structural integration and fully adapting to the miniaturized and high-density packaging requirements of MEMS inertial devices.

[0039] In some possible embodiments, please refer to Figure 2Multiple exhaust slots 312 are arranged radially, and the ends of each exhaust slot 312 that are away from the corresponding positioning hole 311 are interconnected.

[0040] The radially arranged venting grooves 312 extend from the central region of the first connecting part 31 towards the surrounding positioning holes 311, and the inner ends of each venting groove 312 are interconnected to form a unified central region. When the first connecting part 31 is pressed and bonded to the encapsulation shell 1, air in the central region can enter any of the nearest venting grooves 312. Since all venting grooves 312 are interconnected, air can not only flow along its respective venting groove 312 to the corresponding positioning hole 311, but also be redistributed among different venting grooves 312 through the central region, thereby bypassing local areas that may be temporarily blocked by adhesive, ensuring that air is effectively discharged, and achieving effective multi-directional venting of the entire bonding surface.

[0041] Because the venting channels 312 are interconnected, the air pressure in different areas can quickly reach a balanced state. This helps to maintain consistent flow resistance throughout the adhesive during the spreading process, allowing the adhesive layer to expand at a relatively uniform speed. Ultimately, this results in a high-quality bonding interface with uniform thickness and no localized defects such as missing adhesive or air bubbles. At the same time, the venting channels 312 also provide a space to hold the adhesive, thus preventing excess adhesive from overflowing and contaminating other surrounding functional structures to a certain extent.

[0042] In some possible embodiments, please refer to Figure 5 and Figure 7 Each positioning part 4 has a step 41. In the second mating state, the bottom surface of the first connecting part 31 abuts against the top surface of each step 41 to form an adhesive gap between the first connecting part 31 and the encapsulation shell 1. The adhesive gap is used to accommodate adhesive and control the thickness of the adhesive layer.

[0043] Each positioning part 4 is provided with a step 41. The limiting effect of the step 41 controls the bonding gap, thereby achieving stable and controllable adhesive layer thickness. The top surfaces of multiple steps 41 together form a support plane parallel to the inner surface of the encapsulation shell 1. This support plane prevents the first connecting part 31 from moving further downward, thus forming a fixed gap between the bottom surface of the first connecting part 31 and the inner surface of the encapsulation shell 1, which is determined by the height of the step 41.

[0044] The size of this gap is designed to be within the ideal thickness range required for adhesive bonding. Driven by capillary action and external pressure within this gap, the adhesive can uniformly fill the entire area, forming a consistent thickness adhesive layer without excessive compression.

[0045] When bonding the first connecting part 31 to the encapsulation shell 1 in the second mating state, when the first connecting part 31 is pressed downwards, its bottom surface first contacts the adhesive and moves downwards. As the pressing force increases, the bottom surface of the first connecting part 31 abuts against the top surface of the steps 41 on each positioning part 4. The applied pressing force is transmitted through the first connecting part 31 to the steps 41, and then through the positioning parts 4 to the encapsulation shell 1, thereby limiting the first connecting part 31 from being pressed further down. This avoids excessive extrusion of the adhesive, preventing the adhesive layer from becoming too thin, and also reduces local thickness differences in the adhesive layer, resulting in a stable, continuous, and uniform bonding interface between the first connecting part 31 and the encapsulation shell 1. Simultaneously, in this second mating state, although the positioning parts 4 participate in the positioning and adhesive control of the first connecting part 31 through the steps 41 and positioning holes 311, the positioning parts 4 do not abut against the third connecting part 33, thus not weakening the stress isolation effect of the second connecting part 32.

[0046] In some possible embodiments, please refer to Figure 7 Each step 41 has a positioning surface 411 on its side, and multiple positioning surfaces 411 together form a positioning area. In the first mating state, each positioning surface 411 fits against the outer contour of the first connecting part 31 to limit the first connecting part 31.

[0047] In the first mating state, the first connecting part 31 is embedded in the positioning area formed by multiple positioning surfaces 411. Each positioning surface 411 is in contact with the outer contour sidewall of the corresponding position of the first connecting part 31, forming a surface contact limiting constraint. When the chip 2 is bonded to the third connecting part 33 and pressure is applied, if there is a lateral component force or torsional torque, the force will be transmitted through the sidewall of the first connecting part 31 to each positioning surface 411, and then transmitted to the package shell 1 via the step 41 and the positioning part 4. This effectively resists lateral displacement and torsional tendencies, ensuring the firm position of the connector 3 throughout the bonding process, thereby ensuring the bonding effect of the chip 2. At the same time, the positioning surface 411 is directly formed by the side of the step 41, eliminating the need for an additional independent limiting structure, fully utilizing the structural space of the positioning part 4, and effectively improving the structural integration.

[0048] Therefore, the positioning part 4 performs different functions in two stages: in the first mating state, the positioning part 4 provides both outer contour limiting and vertical rigid support through the positioning surface 411 and the top support surface; in the second mating state, the positioning part 4 positions the first connecting part 31 and controls the adhesive layer thickness through the positioning hole 311 and the step 41, but no longer supports the third connecting part 33. This functional switching allows the same positioning part 4 to serve both the chip bonding process and the flexible stress isolation path to be preserved during device operation.

[0049] In some possible embodiments, please refer to Figure 1 and Figure 2The third connecting portion 33 includes a central island 331 and multiple peripheral islands 332. The central island 331 is fixedly connected to the second connecting portion 32. The multiple peripheral islands 332 are arranged around the central island 331 for bonding to the chip 2. Each peripheral island 332 is connected to the central island 331 via a connecting beam 333. Each connecting beam 333 has an elastic degree of freedom to isolate stress transmitted from the central island 331 to the peripheral islands 332.

[0050] Please see Figure 4 Each of the outer islands 332 corresponds one-to-one with a positioning part 4. In the first mating state, the bottom surface of each outer island 332 abuts against the top surface of the corresponding positioning part 4. Please refer to [link / reference]. Figure 6 In the second coordination state, each positioning unit 4 avoids the corresponding outer island 332.

[0051] During the bonding process of chip 2, the top of each positioning part 4 abuts against the bottom surface of the corresponding peripheral island 332. Since the peripheral island 332 corresponds one-to-one with the positioning part 4, each peripheral island 332 obtains independent temporary rigid support. When chip 2 is pressed down, the pressing force is transmitted independently to the corresponding positioning part 4 through each peripheral island 332, rather than to the central island 331 through the connecting beam 333. This avoids the connecting beam 333 from bearing bending or torsional loads during the bonding process, thereby preventing unexpected deformation or damage to the connecting beam 333. After the bonding of chip 2 is completed and switched to the second mating state, each peripheral island 332 separates from the corresponding positioning part 4, and the connecting beam 333 regains its elastic degree of freedom, allowing the peripheral island 332 to undergo slight elastic displacement relative to the central island 331, thereby isolating the stress transmitted from the central island 331 to the peripheral island 332 and chip 2.

[0052] Meanwhile, the multi-point bonding of the outer island 332 to the chip 2 reduces the total bonding contact area, which can further block the stress transmission path. Moreover, the multi-point support method is more suitable for the non-sensitive area layout of the chip 2, which can avoid the core functional area of ​​the chip 2 and prevent the bonding stress from directly affecting the sensitive structure of the chip 2.

[0053] During operation, when stress is transmitted to the central island 331 via the encapsulation shell 1, the first connecting part 31, and the second connecting part 32, the central island 331 undergoes displacement or deformation. This displacement is first transmitted to the peripheral islands 332 through the connecting beams 333. Because the connecting beams 333 possess elastic degrees of freedom, they can absorb the relative displacement between the central island 331 and the peripheral islands 332 through bending, torsion, or tensile deformation, thereby isolating most of the stress. Furthermore, the elastic degrees of freedom of the connecting beams 333 can also isolate thermal stress caused by a mismatch in the coefficients of thermal expansion.

[0054] In some possible embodiments, please refer to Figure 2 and Figure 7Each outer island 332 has a reinforcing rib 334 fixed to its bottom surface, and each positioning part 4 has a limiting groove 42 at its top end suitable for fitting the reinforcing rib 334. In the first mating state, each reinforcing rib 334 is fitted into the corresponding limiting groove 42 to limit the outer island 332. In the second mating state, each reinforcing rib 334 is separated from the corresponding limiting groove 42. Specifically, the reinforcing rib 334 has a cross-shaped structure.

[0055] The reinforcing rib 334 structurally enhances the bending stiffness of the outer island 332, and diffuses the concentrated load during the bonding and pressing of the chip 2 to the support end face of the entire positioning part 4 through the reinforcing rib 334, so as to prevent the outer island 332 from bending and deforming due to local pressure, and ensure that the bonding surface of the top surface of the outer island 332 remains flat, forming a stable and firm bonding interface.

[0056] Meanwhile, the interlocking reinforcing ribs 334 and the limiting grooves 42 form multi-directional rigid constraints in the horizontal plane, which can not only limit the translational displacement of the outer islands 332 along the orthogonal directions in the plane, but also effectively resist the torsional moment generated during the pressing process, preventing individual outer islands 332 from sliding or deflecting. After multiple outer islands 332 are simultaneously laterally limited, the horizontal position and circumferential angle of the entire third connecting part 33 are fixed. Even if there are asymmetrical loads or lateral disturbances during bonding and pressing, there will be no overall offset or torsional misalignment, significantly improving the alignment accuracy and angle consistency of the chip 2 bonding.

[0057] During the bonding operation of chip 2 in the first mating state, the first connecting part 31 is assembled with the positioning area, and the reinforcing ribs 334 on the bottom surface of each peripheral island 332 are embedded in the limiting grooves 42 at the top of the corresponding positioning part 4. At the same time, the bottom surface of the peripheral island 332 abuts against the top of the positioning part 4. The cooperation between the reinforcing ribs 334 and the limiting grooves 42 can limit the lateral slippage and angular deflection of the peripheral islands 332 during the bonding stage, thereby improving the bonding alignment accuracy between chip 2 and peripheral islands 332. When the bonding process is completed and the structure is switched to the second mating state, the reinforcing ribs 334 are completely separated from the positioning part 4 along with the third connecting part 33, and the limiting grooves 42 will not interfere with the elastic deformation space of the third connecting part 33.

[0058] In some possible embodiments, please refer to Figure 4 The second connecting part 32 includes a plurality of connecting posts 321, and the cross-sectional area and / or cross-sectional shape of each connecting post 321 are at least partially different.

[0059] The external stress transmitted from the encapsulated shell 1 to the first connecting part 31 needs to pass through multiple connecting posts 321 before it can be transmitted to the third connecting part 33. Since the cross-sectional area and / or cross-sectional shape of each connecting post 321 are at least partially different, their axial stiffness, bending stiffness, natural frequency and stress attenuation characteristics are different. They can produce differentiated buffering effects for external stresses of different directions, amplitudes and frequencies, thereby reducing the risk of resonant coupling or local stress concentration in a single stiffness connection structure.

[0060] Meanwhile, multiple connecting posts 321 together form a flexible connection path between the first connecting part 31 and the third connecting part 33, which not only ensures the structural connection reliability of the connector 3, but also achieves multi-directional stress isolation through the deformation coordination of each connecting post 321. Since the positioning part 4 is separated from the third connecting part 33 in the second mating state, external stress will not be directly bypassed to the third connecting part 33 through the positioning part 4. Therefore, the elastic isolation function of the second connecting part 32 can continue to play a role during the device operation phase.

[0061] Compared to a flexible platform structure without a positioning part 4, this embodiment directly supports the third connecting part 33 or the outer island 332 through the positioning part 4 during the chip 2 bonding stage, which can reduce the risk of deflection and displacement of the third connecting part 33 caused by bonding pressure. Compared to a structure where the positioning part 4 continues to abut against the third connecting part 33 in the finished product state, this embodiment forms a clearance gap between the positioning part 4 and the third connecting part 33 in the second mating state, which can prevent the positioning part 4 from forming a rigid short-circuit path. Therefore, this embodiment can simultaneously meet the rigid support requirements of the bonding stage and the flexible stress isolation requirements of the working stage.

[0062] On one side of the first connecting portion 31, a venting groove 312 and a positioning hole 311 can be fabricated through processes such as resist coating, photolithography, development, and etching. On the other side of the first connecting portion 31, multiple connecting posts 321 can be fabricated through processes such as resist coating, photolithography, development, and etching. After fabricating the third connecting portion 33 through processes such as resist coating, photolithography, development, and etching, a bonding process is used to connect the third connecting portion 33 and the second connecting portion 32 to form a complete connector 3.

[0063] In summary, the MEMS chip bonding structure provided by this invention, compared with the prior art, allows for a first mating state of the connector 3 during the bonding process between the chip 2 and the third connecting part 33. The first connecting part 31 is embedded within a positioning area formed by multiple positioning parts 4. The positioning parts 4 limit the first connecting part 31 horizontally and provide temporary rigid support for the third connecting part 33 vertically. At this time, the pressing force during the bonding process of the chip 2 is transmitted to the packaging shell 1 through the third connecting part 33 and the positioning parts 4, without forming the main load-bearing path through the second connecting part 32. This avoids unexpected deformation of the second connecting part 32 and the third connecting part 33 during the bonding stage, ensuring a uniform, firm, and accurately aligned bonding interface between the chip 2 and the third connecting part 33.

[0064] After chip 2 is bonded, connector 3 switches to the second mating state. The first connecting part 31 is bonded and fixed to the package shell 1, and each positioning part 4 separates from the third connecting part 33 to form a clearance gap. The positioning part 4 no longer restricts the elastic deformation of the second connecting part 32 and the third connecting part 33. The deformation stress of the package shell 1 caused by external vibration, impact or temperature change is transmitted through the first connecting part 31 and buffered and attenuated by the elastic deformation of the second connecting part 32, thereby achieving stress isolation of chip 2 on the third connecting part 33.

[0065] Therefore, by switching the function of the same set of positioning parts 4 under different mating states, the present invention achieves the unity of "rigid support in the bonding stage" and "flexible isolation in the working stage", solving the problem that existing flexible platform structures are difficult to balance between packaging process and device service performance.

[0066] This invention also provides a MEMS inertial device, including any of the aforementioned MEMS chip bonding structures. Due to the use of this MEMS chip bonding structure, the MEMS inertial device can receive temporary rigid support from the positioning part 4 during the chip 2 bonding process, thereby improving the robustness and alignment accuracy of the bonding interface. Furthermore, it can achieve stress isolation through the second connecting part 32 during operation, thus reducing the impact of vibration, impact, or thermal deformation stress transmitted from the package 1 on the chip 2, and improving the stability, structural reliability, and service life of the MEMS inertial device.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A MEMS chip bonding structure for connecting a package shell (1) and a chip (2), characterized in that, include: The connector (3) includes a first connecting part (31), a second connecting part (32) and a third connecting part (33); the first connecting part (31) is used to bond with the package shell (1), the third connecting part (33) is used to bond with the chip (2), and the second connecting part (32) is located between the first connecting part (31) and the third connecting part (33) to isolate the stress transmitted from the package shell (1) to the chip (2); Multiple positioning parts (4) are fixedly disposed on the encapsulation shell (1) and arranged around it to form a positioning area that matches the outer contour of the first connecting part (31); The connector (3) and each of the positioning parts (4) have a first mating state and a second mating state; In the first mating state, the first connecting part (31) is embedded in the positioning area, and the top of each positioning part (4) abuts against the bottom surface of the third connecting part (33) to provide temporary rigid support for the third connecting part (33) during the bonding process between the chip (2) and the third connecting part (33). In the second mating state, the first connecting part (31) is released from the positioning area, each of the positioning parts (4) avoids the third connecting part (33), and the first connecting part (31) is bonded to the encapsulation shell (1).

2. The MEMS chip bonding structure as described in claim 1, characterized in that, The first connecting part (31) is provided with a plurality of positioning holes (311) for the positioning part (4) to pass through, and the positioning holes (311) correspond one-to-one with the positioning part (4); In the first mating state, each of the positioning parts (4) is separated from the corresponding positioning hole (311); In the second mating state, each of the positioning parts (4) is inserted into the corresponding positioning hole (311) to position the first connecting part (31).

3. The MEMS chip bonding structure as described in claim 2, characterized in that, The first connecting part (31) has a plurality of exhaust grooves (312) on the side facing the encapsulation tube shell (1). The exhaust grooves (312) correspond one-to-one with the positioning holes (311) and are interconnected. In the second mating state, during the bonding process of the first connecting part (31) and the encapsulation shell (1), the air between the first connecting part (31) and the encapsulation shell (1) is discharged along the venting groove (312) to the positioning hole (311) so that the adhesive fills the gap between the first connecting part (31) and the encapsulation shell (1).

4. The MEMS chip bonding structure as described in claim 3, characterized in that, The multiple exhaust grooves (312) are arranged radially, and the ends of each exhaust groove (312) opposite to the corresponding positioning hole (311) are interconnected.

5. The MEMS chip bonding structure as described in claim 1, characterized in that, Each of the positioning parts (4) has a step (41); In the second mating state, the bottom surface of the first connecting part (31) abuts against the top surface of each step (41) to form an adhesive gap between the first connecting part (31) and the encapsulation shell (1), the adhesive gap being used to accommodate adhesive and control the thickness of the adhesive layer.

6. The MEMS chip bonding structure as described in claim 5, characterized in that, Each of the steps (41) forms a positioning surface (411) on its side, and the multiple positioning surfaces (411) together enclose the positioning area; In the first mating state, each of the positioning surfaces (411) fits against the outer contour of the first connecting part (31) to limit the first connecting part (31).

7. The MEMS chip bonding structure as described in claim 1, characterized in that, The third connecting part (33) includes: The central island (331) is fixedly connected to the second connecting part (32); Multiple peripheral islands (332) are arranged around the central island (331) for bonding with the chip (2); each peripheral island (332) is connected to the central island (331) by a connecting beam (333); Each of the connecting beams (333) has an elastic degree of freedom to isolate the stress transmitted from the central island (331) to the outer island (332); The outer islands (332) correspond one-to-one with the positioning parts (4). In the first engagement state, the bottom surface of each outer island (332) abuts against the top of the corresponding positioning part (4). In the second engagement state, each positioning part (4) avoids the corresponding outer island (332).

8. The MEMS chip bonding structure as described in claim 7, characterized in that, Each of the outer islands (332) has a reinforcing rib (334) fixed on its bottom surface, and each of the positioning parts (4) has a limiting groove (42) at its top end that is suitable for fitting the reinforcing rib (334). In the first engagement state, each of the reinforcing ribs (334) is fitted into the corresponding limiting groove (42) to limit the peripheral island (332); in the second engagement state, each of the reinforcing ribs (334) is separated from the corresponding limiting groove (42).

9. The MEMS chip bonding structure as described in claim 1, characterized in that, The second connecting part (32) includes a plurality of connecting posts (321), each of which has a cross-sectional area and / or cross-sectional shape that are at least partially different.

10. A MEMS inertial device, characterized in that, Includes the MEMS chip bonding structure described in any one of claims 1 to 9 above.

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