A microelectromechanical system package structure

Abstract

The application discloses a micro-electro-mechanical system packaging structure and relates to the technical field of micro-electro-mechanical systems. The micro-electro-mechanical system packaging structure comprises a substrate, a control chip and a device chip which are stacked from top to bottom and electrically connected with each other, and a packaging body for packaging the substrate, the control chip and the device chip, wherein a limiting structure for resisting deformation of the device chip is arranged between the packaging body and the device chip. The micro-electro-mechanical system packaging structure has the limiting structure arranged between the packaging body and the device chip, so that the shrinkage force of the packaging body on the device layer is reduced, and the stress deformation of the device layer is reduced.

Description

Technical Field

[0001] This invention relates to the field of microelectromechanical systems (MEMS) technology, and in particular to a MEMS packaging structure. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS) are a recent development in the field of integrated circuits. MEMS include devices fabricated using semiconductor technology to form mechanical and electronic components. Common applications of MEMS devices include resonators, accelerometers, pressure sensors, actuators, mirrors, heaters, and printer heads.

[0003] After being packaged, microelectromechanical systems (MEMS) are applied to various electronic products. Some MEMS products operate in constant-temperature environments, while others operate in variable-temperature environments. In particular, MEMS products operating in environments with large temperature variations experience excessive forces exerted by the package on the internal device layers due to temperature changes. This causes deformation of the device layers and affects their normal operation. Summary of the Invention

[0004] This application provides a microelectromechanical system (MEMS) packaging structure to reduce stress deformation of the device layer.

[0005] To solve the above-mentioned technical problems, the technical solution provided in this application is as follows:

[0006] A microelectromechanical system (MEMS) packaging structure includes a substrate, a control chip, and a device chip stacked from top to bottom and electrically connected to each other, and a package encapsulating the substrate, control chip, and device chip, wherein a limiting structure is disposed between the package and the device chip to resist deformation of the device chip.

[0007] The package includes a first package and a second package. The first package encapsulates the substrate, the control chip, and the device chip. The second package protrudes from the top surface of the first package and is located directly above the device chip, encapsulating the device chip. The periphery of the second package is located within the edge of the first package.

[0008] The distance between the surface of the second package facing away from the first package and the top surface of the first package is the thickness of the second package, which is 50 μm thick.

[0009] The device chip includes a first substrate and a second substrate spaced apart from each other, and a device layer disposed between the first substrate and the second substrate. The first substrate is fixedly connected to the top surface of the control chip away from the substrate, and the device layer is electrically connected to the control chip.

[0010] The second substrate has at least one groove on its top surface facing away from the device layer, and the package fills the groove.

[0011] The groove is configured as a rectangular groove.

[0012] The groove has a length and width of 500 μm and a depth of 30 μm.

[0013] The device layer includes a connection portion, an actuation portion, and an electrode portion. The connection portion and the electrode portion are fixedly connected to the first substrate and / or the second substrate. The actuation portion is coupled to the connection portion. The electrode portion is disposed adjacent to the actuation portion and is electrically connected to the control chip to drive the actuation portion.

[0014] The connecting portion and the electrode portion are bonded to the first substrate and / or the second substrate via anchor point eutectic bonding.

[0015] The encapsulation body is configured as an epoxy encapsulant, a silicone encapsulant, a polyurethane encapsulant, an ultraviolet-curable encapsulant, or a combination thereof.

[0016] The beneficial effects of this application are: the above-mentioned microelectromechanical system packaging structure has a limiting structure between the package body and the device chip to resist the deformation of the device chip, thereby reducing the shrinkage force of the package body on the device layer and reducing the stress deformation of the device layer. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0018] Figure 1 This is a cross-sectional schematic diagram of the packaging structure of a microelectromechanical system (MEMS) in the prior art;

[0019] Figure 2 This is a cross-sectional schematic diagram of the microelectromechanical system packaging structure according to the first embodiment of this application;

[0020] Figure 3 This is a cross-sectional view of the microelectromechanical system (MEMS) packaging structure according to the second embodiment of this application. Figure 1 ;

[0021] Figure 4 This is a cross-sectional view of the microelectromechanical system (MEMS) packaging structure according to the second embodiment of this application. Figure 2 ;

[0022] Figure 5 This is a cross-sectional view of the microelectromechanical system (MEMS) packaging structure according to the second embodiment of this application. Figure 3 ;

[0023] Figure 6 This is a cross-sectional schematic diagram of the microelectromechanical system packaging structure according to the third embodiment of this application. Figure 1 ;

[0024] Figure 7 This is a cross-sectional schematic diagram of the microelectromechanical system packaging structure according to the third embodiment of this application. Figure 2 ;

[0025] Figure 8 This is a cross-sectional schematic diagram of the microelectromechanical system packaging structure according to the third embodiment of this application. Figure 3 ;

[0026] Figure 9 This is a partial schematic diagram of a microelectromechanical system (MEMS) packaging structure in one embodiment of this application;

[0027] Figure 10 This is a deformation diagram of the first gap plane in the microelectromechanical system packaging structure in the prior art and various embodiments of this application;

[0028] Figure 11 This is a deformation diagram of the second gap plane in the microelectromechanical system packaging structure in the prior art and various embodiments of this application;

[0029] Figure 12 This is a diagram showing the warping deformation of the first gap in the microelectromechanical system packaging structure in the prior art and various embodiments;

[0030] Figure 13 This is a diagram showing the warping deformation of the second gap in the microelectromechanical system packaging structure in the prior art and various embodiments. Detailed Implementation

[0031] 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 a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] It should be noted that the terms "first," "second," etc., used below are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of the stated features.

[0033] The terminology used in this specification is for illustrative purposes and is not intended to limit the invention. It should also be noted that, unless otherwise explicitly stated and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection via an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art will readily understand the specific meanings of the above terms within the context of this invention.

[0034] Please see Figure 1 , Figure 1 This is a cross-sectional schematic diagram of a microelectromechanical system (MEMS) packaging structure according to an embodiment of the prior art.

[0035] The existing microelectromechanical system (MEMS) package structure 800 includes a substrate 81, a control chip 82 (CMOS Die), a device chip 83 (MEMS Die), and a package body 84. The control chip 82 is stacked on top of the substrate 81 and bonded to the top of the substrate 81 with an adhesive (e.g., conductive epoxy resin). The device chip 83 is stacked on the side of the control chip 82 facing away from the substrate 81. The device chip 83 comprises a first substrate 830 (wafer I), a device layer 831 (Device Layer), and a second substrate 832 (wafer II). The first substrate 830 and the second substrate 832 are spaced apart and opposite each other, with the device layer 831 located between the first substrate 830 and the second substrate 832.

[0036] The package 84 encapsulates a substrate 81, a control chip 82, and a device chip 83 therein, with at least the bottom of the substrate 81 exposed to allow for electrical connection between the microelectromechanical system package structure and an external circuit.

[0037] In the aforementioned microelectromechanical system (MEMS) packaging structure, the deformation of device layer 831 is only affected by the second substrate 832. Using device layer 831 as the interface, the lower first substrate 830 is integrated with the control chip 82 and the substrate 81, jointly resisting the lower shrinkage deformation of the package 84. The second substrate 832 is covered by the upper part of the package 84, and the shrinkage deformation of the upper part of the package 84 is mainly resisted by the second substrate 832. Therefore, the shrinkage deformation of the upper part of the package 84 is resisted by thickening the second substrate 832. As the thickness of the second substrate 832 increases, the thickness of the package 84 also increases accordingly. At this time, the increase in the volume shrinkage force of the package 84 will exceed the increase in the rigidity of the second substrate 832, resulting in increased deformation of the second substrate 832, which in turn leads to increased deformation of device layer 831, affecting the normal operation of device layer 831.

[0038] Therefore, it is necessary to improve the packaging structure of microelectromechanical systems (MEMS) by incorporating a limiting structure between the package and the device chip to resist deformation of the device chip. This reduces the contractile force exerted by the package on the device layer, minimizes the stress deformation of the device layer, and ensures its normal operation.

[0039] Specifically, please refer to the first embodiment. Figure 2 , Figure 2 This is a schematic diagram of the microelectromechanical system packaging structure according to the first embodiment of this application.

[0040] The microelectromechanical system (MEMS) package structure 100 includes a substrate 1, a control chip 2, a device chip 3, and a package body 4. The control chip 2 is stacked on top of the substrate 1 and is bonded to the top of the substrate 1 by an adhesive (e.g., conductive epoxy resin). The device chip 3 is stacked on the side of the control chip 2 facing away from the substrate 1. The substrate 1, control chip 2, and device chip 3 are electrically connected to each other.

[0041] The device chip 3 includes a first substrate 30 (wafer Ⅰ), a device layer 31 (Device Layer), and a second substrate 32 (wafer Ⅱ), wherein the first substrate 30 and the second substrate 32 are positioned opposite each other with a vertical gap, and the device layer 31 is located between the first substrate 30 and the second substrate 32. The device layer 31 is electrically connected to the control chip 2.

[0042] Device layer 31 includes a connection portion 310, an actuation portion 311, and an electrode portion (not shown in the figure). The connection portion 310 and the electrode portion are fixedly connected to the first substrate 30 and the second substrate 32, and the connection portion 310 and the actuation portion 311 are coupled to each other. The electrode portion is disposed adjacent to the actuation portion 311 and is electrically connected to the control chip 2 to drive the actuation portion 311. Preferably, a gap is left between the electrode portion and the actuation portion 311.

[0043] Of course, the connecting part 310 and the electrode part may also be fixedly connected only to the first substrate 30 or the second substrate 32.

[0044] Device layer 31 can be configured as a micromechanical structure such as a resonator, beam, arm, or electrostatic motor. The first substrate 30 and the second substrate 32 can have various dielectric materials used to form integrated circuits. Chemicals can be degassed from the dielectric materials and enter the cavity. Gases can alter the environment surrounding the microelectromechanical system package structure and affect its operation.

[0045] The connecting portion 310 and the electrode portion are eutectic bonded to the first substrate 30 and the second substrate 32 via anchor points. Eutectic bonding is a bonding method between two specific metals, and commonly used metal configurations include, but are not limited to, Al-Ge (aluminum germanium), Au-Ge (gold germanium), and Au-Si (gold silicon).

[0046] A groove 320 is formed on the top surface of the second substrate 32 facing away from the device layer 31. That is, the opening direction of the groove 320 is on the top surface of the second substrate 32 away from the device layer 31. The number of grooves 320 can be one or more.

[0047] The package 4 is made of plastic encapsulation material, which encapsulates the substrate 1, the control chip 2, and the device chip 3, and the package 4 fills the recess 320. The substrate 1 has at least its bottom exposed to allow for electrical connection between the microelectromechanical system package structure and external circuitry.

[0048] With device layer 31 as the boundary, when the temperature changes, especially when the temperature changes drastically, the entire microelectromechanical system (MEMS) package structure is prone to downward bending deformation relative to device layer 31. This is mainly because the lower volume of package 4 is larger, generating a greater contraction force. This bending deformation is transmitted to the top second substrate 32. Therefore, if the package 4 in the upper local area of ​​the second substrate 32 is appropriately enlarged, the reverse contraction force at the top of package 4 can be increased.

[0049] Therefore, at least one groove 320 is formed on the top surface of the second substrate 32 facing away from the device layer 31, and the package 4 fills the groove 320, thereby increasing the package 4 in the upper local area of ​​the second substrate 32.

[0050] In this embodiment, there is one groove 320, which is located at the middle of the top surface of the second substrate 32. The thickness of the first substrate 30 is 100 μm, and the thickness of the second substrate 32 is 100 μm. The groove 320 is rectangular, with a length and width of 500 μm and a depth of 30 μm.

[0051] The groove 320 and the package 4 form the aforementioned defined structure. The groove 320 is filled with the encapsulation material of the package 4, which appropriately increases the volume of the package 4 in the upper part of the second substrate 32. When the temperature changes, especially when the temperature changes drastically, the reverse contraction force on the upper part of the package 4 can be increased, thereby reducing the deformation of the device chip 3.

[0052] Common encapsulants mainly include epoxy encapsulants, silicone encapsulants, polyurethane encapsulants, UV-curable encapsulants, or combinations thereof. Encapsulants can be transparent or colorless, or made in almost any color as needed. Epoxy encapsulants are generally rigid and inflexible; most are two-component and require mixing before use, while a small number are single-component and require heat to cure. Silicone encapsulants are almost all soft and elastic, similar to epoxy. Most are two-component and require mixing before use, while a small number are single-component and require heat to cure.

[0053] It is understood that the rectangular groove 320 has a length and width of 500µm and a depth of 30µm. The length, width, and depth of the groove 320 can also be other suitable dimensions. The groove 320 can also be set to a circular, elliptical, or irregular shape; there is no limitation here.

[0054] Please see Figure 3 , Figure 3 This is a cross-sectional view of the microelectromechanical system (MEMS) packaging structure according to the second embodiment of this application. Figure 1 .

[0055] The second embodiment further improves upon the structure of the first embodiment. The improvement lies in that the package 4 includes a first package 40 and a second package 41. The first package 40 encapsulates the substrate 1, the control chip 2, and the device chip. The second package 41 protrudes from the top surface of the first package 40, is located directly above the device chip 3, and encapsulates the device chip 3. The periphery of the second package is within the edge of the first package 40.

[0056] Both the first package 40 and the second package 41 are rectangular, with the bottom surface of the second package 41 coplanar with the top surface of the first package 40. The first package 40 and the second package 41 are stepped, and the side surface of the second package 41 is perpendicular to the top surface of the first package 40. A thickness difference exists between the portion of the top surface of the first package 40 surrounding the second package 41 and the second package 41, reducing the thickness of this portion and thus appropriately thinning the top perimeter of the first package 40. The second package 41 fills the groove 320.

[0057] The second package 41 fills the groove 320, thereby increasing the package 4 in the upper local area of ​​the second substrate 32. In addition, when the temperature changes, especially when the temperature changes drastically, the contractile force of the second package 41 on the device chip 3 decreases, that is, the contractile force of the package 4 on the device chip 3 decreases, thereby reducing the deformation of the device chip 3 and not affecting the normal operation of the device chip.

[0058] In this embodiment, the thickness of the first substrate 30 is 100 μm, the thickness of the second substrate 32 is 100 μm, and the thickness of the second package 41 is 50 μm (the distance between the surface of the second package 41 facing away from the first package 40 and the top surface of the first package 40 is the thickness of the second package 41). The second package 41 is rectangular, with a length and width of 1000 μm. Of course, the second package 41 can also be circular, elliptical, or other shapes, as long as the thickness of the second package 41 is 50 μm. The groove 320 is rectangular, with a length and width of 500 μm and a depth of 30 μm.

[0059] While ensuring that the thickness of the second package 41 is 50um, a thickness difference is formed between the portion of the top surface of the first package 40 surrounding the second package 41 and the second package 41, which reduces the thickness of the portion of the top surface of the first package 40 surrounding the second package 41, thereby appropriately thinning the top perimeter of the first package 40.

[0060] Alternatively, the second package 41 can be formed by a raised top surface of the first package 40, located directly above the device chip 3 and encapsulating the device chip 3 therein, with the second package 41 filling the groove 320. The first package 40 and the second package 41 are transitioned by a slope or curved surface, such as... Figure 4 and Figure 5 As shown.

[0061] The groove 320 and the second package 41, the second package 41 and the portion of the second package 41 surrounding the top surface of the first package 40 together form the above-mentioned limiting structure. The groove 320 is filled with the encapsulation material of the package 4, which appropriately increases the volume of the package 4 in the upper local area of ​​the second substrate 32. When the temperature changes, especially when the temperature changes drastically, the reverse contraction force on the upper part of the package 4 can be increased, which, together with the second package 41, reduces the deformation of the device chip 3.

[0062] Furthermore, the overall microelectromechanical system (MEMS) packaging structure is axially symmetric with its central axis as the axis of symmetry.

[0063] Please see Figure 6 , Figure 6 This is a cross-sectional schematic diagram of the microelectromechanical system packaging structure according to the third embodiment of this application. Figure 1 .

[0064] The third embodiment further improves upon the structure of the second embodiment described above. The improvement lies in the elimination of the recess 320. The package 4 is still configured with the same structure as in the second embodiment.

[0065] The package 4 includes a first package 40 and a second package 41. The first package 40 encapsulates the substrate 1, the control chip 2, and the device chip. The second package 41 protrudes from the top surface of the first package 40, is located directly above the device chip 3, and encapsulates the device chip 3. The periphery of the second package is within the edge of the first package 40.

[0066] Both the first package 40 and the second package 41 are rectangular, with the bottom surface of the second package 41 coplanar with the top surface of the first package 40. The first package 40 and the second package 41 are stepped, with the side surface of the second package 41 perpendicular to the top surface of the first package 40. A thickness difference exists between the portion of the top surface of the first package 40 surrounding the second package 41 and the second package 41, reducing the thickness of this portion. This results in a slightly thinner top perimeter of the first package 40. When the temperature changes, especially drastic changes, the contractile force exerted by the second package 41 on the device chip 3 is reduced, thereby minimizing the deformation of the device chip 3 and ensuring its normal operation.

[0067] In this embodiment, the thickness of the first substrate 30 is 100 μm, the thickness of the second substrate 32 is 100 μm, and the thickness of the second package 41 is 50 μm (the distance between the surface of the second package 41 facing away from the first package 40 and the top surface of the first package 40 is the thickness of the second package 41). The second package 41 is rectangular, with a length and width of 1000 μm. Of course, the second package 41 can also be circular, elliptical, or other shapes, as long as the thickness of the second package 41 is 50 μm.

[0068] While ensuring that the thickness of the second package 41 is 50um, a thickness difference is formed between the portion of the top surface of the first package 40 surrounding the second package 41 and the second package 41, which reduces the thickness of the portion of the top surface of the first package 40 surrounding the second package 41, thereby appropriately thinning the top perimeter of the first package 40.

[0069] Alternatively, the second package 41 can be formed by a raised top surface of the first package 40, located directly above the device chip 3 and encapsulating the device chip 3 therein, with the second package 41 filling the groove 320. The first package 40 and the second package 41 are transitioned by a slope or curved surface, such as... Figure 7 and Figure 8 As shown.

[0070] The second package 41 and the portion of the first package 40 surrounding the second package 41 together form the aforementioned limiting structure. When the temperature changes, especially when the temperature changes drastically, the reverse contraction force on the upper part of the package 4 can be increased, and together with the second package 41, the deformation of the device chip 3 is reduced.

[0071] Preferably, the second substrate 32 is provided with at least one through-silicon via 321 (TSV), and the control chip 2 forms a signal connection with the electrode through the TSV 321 to control the operation of the actuator 311.

[0072] Furthermore, the overall microelectromechanical system (MEMS) packaging structure is axially symmetric with its central axis as the axis of symmetry.

[0073] Please see Figure 9 , Figure 9 This is a partial schematic diagram of the microelectromechanical system packaging structure in one embodiment of this application.

[0074] The actuator 311 is configured as a ring resonator, and the electrode part includes a drive electrode 312 and a sensing electrode 313. The sensing electrode 313 is placed inside the ring resonator and has a first gap 3111 between it and the ring resonator. The drive electrode 312 surrounds the ring resonator and has a second gap 3112 between it and the ring resonator.

[0075] The driving electrode 312 is connected to the driving circuit to induce the ring resonator to oscillate or vibrate, wherein the oscillation or vibration has one or more resonant frequencies.

[0076] The sensing electrode 313 is connected to the sensing circuit to sense, sample, and / or detect signals having one or more resonant frequencies.

[0077] The driving electrode 312 and sensing electrode 313, the driving circuit and the sensing circuit, can be of conventional and well-known types, or can be electrodes of any type and / or shape now known or developed in the future. Furthermore, the physical electrode structure can include, for example, capacitors, piezoresistors, piezoelectrics, inductors, magnetoresistors, and thermals.

[0078] Thus, the microelectromechanical system (MEMS) package structure is configured as a MEMS oscillator, and this is used as the simulation object. The material parameters are shown in Table 1.

[0079] Table 1 shows the material parameters of the microelectromechanical system (MEMS) packaging structure.

[0080] Si 162 0.27 <![CDATA[2.6e -6 ]]> <![CDATA[SiO2]]> 73 0.17 <![CDATA[4e -7 ]]> Cu 110 0.34 <![CDATA[1.8e -5 ]]> Epoxy resin 24.6 0.136 <![CDATA[1.55e -5 ]]>

[0081] In the packaging structure of microelectromechanical systems (MEMS), the entire component is subjected to a high temperature of 130°C to solidify the colloid used as the encapsulation body (at which point the colloid can be considered to be in a state of zero stress), and then returned to room temperature. After that, it undergoes a 260°C SMT soldering process. SMT (Surface Mount Technology) is an abbreviation or short for surface mount technology, which refers to the process of mounting surface mount devices (SMDs) onto the surface of a PCB (or its board surface) using certain processes, equipment, and materials, and then performing soldering, cleaning, and testing to finally complete the assembly.

[0082] The elastic modulus is calculated as stress divided by strain in a uniaxial stress state. Generally, when an external force is applied to an elastic body, the body will change shape (called "deformation"). During the elastic deformation stage, the stress and strain of a material are directly proportional (i.e., they conform to Hooke's Law), and this proportionality constant is called the elastic modulus. The elastic modulus is a physical quantity that describes the elasticity of a material; it is a general term and can be expressed as "Young's modulus," "shear modulus," "bulk modulus," etc.

[0083] Poisson's ratio is the ratio of the transverse normal strain to the axial normal strain when a material is subjected to uniaxial tension or compression. It is also called the transverse deformation coefficient and is an elastic constant that reflects the transverse deformation of a material.

[0084] The coefficient of thermal expansion is a physical quantity that measures the degree of thermal expansion of solid materials. It is the relative change in length or volume of an object per unit length or volume when the temperature increases by 1°C. It can be expressed by the average linear expansion coefficient α or the average volumetric expansion coefficient β.

[0085] Simulation calculation conditions: The overall temperature drops from 130℃ to 25℃, a decrease of 105℃. Simulation refers to setting specific parameters in a particular model, then detecting relevant indicator values ​​and analyzing their changes. It is a type of production process, mainly including real-time visualization of complex processes and real-time processing of complex geometric models.

[0086] Table 2 is a table of electrode deformation values ​​in the prior art and various embodiments of the microelectromechanical system packaging structure; Figure 10 This is a deformation diagram of the first gap plane in the microelectromechanical system packaging structure in the prior art and various embodiments of this application; Figure 11 This is a deformation diagram of the second gap plane in the microelectromechanical system packaging structure in the prior art and various embodiments of this application; Figure 12 This is a diagram showing the warping deformation of the first gap in the microelectromechanical system packaging structure in the prior art and various embodiments; Figure 13 This is a diagram showing the warping deformation of the second gap in the microelectromechanical system packaging structure in the prior art and various embodiments.

[0087] Table 2 shows the electrode deformation values ​​in the prior art and various embodiments of the microelectromechanical system packaging structure.

[0088]

[0089] See Table 2. Figure 10 , Figure 11 , Figure 12 and Figure 13 Therefore, we can conclude that:

[0090] 1. Compared with the prior art, the in-plane deformation of the first gap 3111 in the first embodiment is reduced by 7%, and the in-plane deformation of the second gap 3112 is reduced by 5%; the warping deformation of the first gap 3111 is reduced by 12%, and the warping deformation of the second gap 3112 is reduced by 10%.

[0091] 2. Compared with the prior art, the in-plane deformation of the first gap 3111 in the second embodiment is reduced by 32%, and the in-plane deformation of the second gap 3112 is reduced by 29%; the warping deformation of the first gap 3111 is reduced by 16%, and the warping deformation of the second gap 3112 is reduced by 19%.

[0092] 3. Compared with the prior art, the in-plane deformation of the first gap 3111 in the third embodiment is reduced by 14%, and the in-plane deformation of the second gap 3112 is reduced by 13%; the warping deformation of the first gap 3111 is reduced by -3%, and the warping deformation of the second gap 3112 is reduced by 2%.

[0093] Compared with the prior art, the first, second, and third embodiments significantly reduce the in-plane deformation of the first gap and the in-plane deformation of the second gap; compared with the prior art, the first and second embodiments also significantly reduce the warping deformation of the first gap and the warping deformation of the second gap.

[0094] Compared with the prior art, the first, second, and third embodiments all show significantly reduced overall deformation.

[0095] In summary, by optimizing the shape of the package 4 in the microelectromechanical system (MEMS) packaging structure, especially the portion of the package 4 above the device layer 31, the deformation impact of the package 4 on the device layer 31 can be better reduced, and the deformation of the device layer 31 can be significantly reduced. The specific technical solution is as described above.

[0096] In the description of this specification, the terms "one embodiment," "another embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0097] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A microelectromechanical system (MEMS) packaging structure, comprising a substrate, a control chip, and a device chip stacked from top to bottom and electrically connected to each other, and a package encapsulating the substrate, control chip, and device chip, characterized in that, The device chip includes a first substrate and a second substrate that are spaced apart vertically, and a device layer disposed between the first substrate and the second substrate, wherein the first substrate is fixedly connected to the top surface of the control chip away from the substrate, and the device layer is electrically connected to the control chip; The second substrate has at least one groove on its top surface facing away from the device layer, and the package fills the groove.

2. The microelectromechanical system packaging structure as described in claim 1, characterized in that, The package includes a first package and a second package. The first package encapsulates the substrate, the control chip, and the device chip. The second package protrudes from the top surface of the first package and is located directly above the device chip, encapsulating the device chip. The periphery of the second package is within the edge of the first package.

3. The microelectromechanical system packaging structure as described in claim 2, characterized in that, The distance between the surface of the second package facing away from the first package and the top surface of the first package is the thickness of the second package, which is 50 μm thick.

4. The microelectromechanical system packaging structure as described in claim 1, characterized in that, The groove is configured as a rectangular groove.

5. The microelectromechanical system packaging structure as described in claim 4, characterized in that, The groove is 500µm long and wide, and 30µm deep.

6. The microelectromechanical system packaging structure as described in claim 1, characterized in that, The device layer includes a connection portion, an actuation portion, and an electrode portion. The connection portion and the electrode portion are fixedly connected to the first substrate and / or the second substrate. The actuation portion is coupled to the connection portion. The electrode portion is disposed adjacent to the actuation portion and is electrically connected to the control chip to drive the actuation portion.

7. The microelectromechanical system packaging structure as described in claim 6, characterized in that, The connecting portion and the electrode portion are eutectic bonded to the first substrate and / or the second substrate via anchor points.

8. The microelectromechanical system packaging structure as described in claim 1, characterized in that, The encapsulation is configured as an epoxy encapsulant, a silicone encapsulant, a polyurethane encapsulant, an ultraviolet-curable encapsulant, or a combination thereof.

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