MEMS packaging structure and forming method thereof, vehicle-mounted chip and vehicle

Abstract

The invention relates to an MEMS packaging structure and a forming method thereof, a vehicle-mounted chip and a vehicle, the MEMS packaging structure comprises a first MEMS device, a second MEMS device and a combination structure, the second MEMS device is combined with the first MEMS device, the combination structure is located between the first MEMS device and the second MEMS device, the first MEMS device is connected with the second MEMS device, and the second MEMS device is connected with the combination structure. And a first cavity is formed between the combination structure and the first MEMS device. Therefore, the first MEMS device and the second MEMS device can be stacked up and down through the combination structure, so that the occupied area of the packaging structure can be reduced.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a MEMS packaging structure and a method for forming the same, an on-board chip and a vehicle. Background Art

[0002] Microelectromechanical system (MEMS) devices are microscopic devices that integrate mechanical and electrical components to sense physical quantities and / or act according to the surrounding environment. In recent years, MEMS devices have become increasingly common. For example, MEMS accelerometers and motion sensors are commonly found in airbag deployment systems (ADS), tablet computers, and smartphones.

[0003] Nowadays, the development of sensors is becoming more and more diversified, and the integration of multiple chips has become the mainstream development direction of chips, such as integrating gyroscopes and accelerometers into one. When the two chips are manufactured on wafers, they are usually packaged in a left-right two-in-one arrangement after the first chip and the second chip are manufactured separately, resulting in a larger packaging structure area. Summary of the invention

[0004] The embodiments of the present application provide a MEMS packaging structure and a method for forming the same, an on-board chip and a vehicle, which can reduce the area of ​​the MEMS packaging structure to at least partially solve the above-mentioned technical problems.

[0005] In order to achieve the above object, according to a first aspect of the present application, a MEMS packaging structure is provided, comprising:

[0006] The first MEMS device;

[0007] a second MEMS device, combined with the first MEMS device;

[0008] The bonding structure is located between the first MEMS device and the second MEMS device, and a first cavity is formed between the bonding structure and the first MEMS device.

[0009] In some embodiments, the bonding structure includes a first bonding layer, the first bonding layer includes a first surface and a second surface opposite to each other, the first surface contacts a surface of the second MEMS device, and the second surface and the first MEMS device form the first cavity.

[0010] In some embodiments, the first bonding layer has a groove recessed relative to the second surface, and the groove constitutes a part of the first cavity.

[0011] In some embodiments, it also includes:

[0012] The first sealing structure is located between the first bonding layer and the first MEMS device. The first sealing structure, the second surface and the first MEMS device form the first cavity.

[0013] In some embodiments, the bonding structure further includes a second bonding layer bonded to the first bonding layer, and the second bonding layer is located between the first bonding layer and the second MEMS device.

[0014] In some embodiments, the first MEMS device includes a first device structure, the first device structure includes a first sensitive surface and a first non-sensitive surface opposite to each other, and the first cavity is formed between the first sensitive surface and the bonding structure.

[0015] In some embodiments, the first device structure includes a first sensitive region and a first lead-out region, and the first cavity is disposed corresponding to the first sensitive region.

[0016] In some embodiments, the first MEMS device further includes a first pad, and the first pad is located on the first sensitive surface and in the first lead-out region.

[0017] In some embodiments, an integrated circuit structure is further included, and the integrated circuit structure is electrically connected to the first pad.

[0018] In some embodiments, it also includes:

[0019] a cover plate, located at a side of the second MEMS device away from the first MEMS device;

[0020] The second sealing structure is located between the second MEMS device and the cover plate, and a second cavity is formed between the cover plate, the second sealing structure and the second MEMS device.

[0021] In some embodiments, the method further includes: an integrated chip, wherein the integrated chip is located on a side of the cover plate away from the first MEMS device, and the integrated circuit structure is located within the integrated chip.

[0022] In some embodiments, it also includes:

[0023] a third bonding layer, located on the first non-sensitive surface of the first device structure;

[0024] A substrate is bonded to a side of the third bonding layer away from the first device structure.

[0025] In some embodiments, the integrated circuit structure is located within the substrate.

[0026] In some embodiments, the first device structure further comprises:

[0027] A first sensitive structure, wherein the first sensitive structure has a first connecting through hole, and a side surface of the first sensitive structure is the first sensitive surface;

[0028] a first sacrificial layer, located on a side of the first sensitive structure away from the second MEMS device, and having a third cavity in the first sacrificial layer, wherein the third cavity is connected to the first cavity through the first connecting through hole;

[0029] The first barrier layer is located on a side of the first sacrificial layer away from the first sensitive structure.

[0030] In some embodiments, the first MEMS device further includes a first redistribution layer located on the first non-sensitive surface, and the first redistribution structure includes a first connection layer and a conductive plug connected to the first connection layer;

[0031] The first connection layer is located on the first non-sensitive surface, the conductive plug penetrates the first barrier layer and the first sacrificial layer, and the conductive plug is electrically connected to the first sensitive structure.

[0032] In some embodiments, the third bonding layer is located on a side of the substrate close to the first redistribution layer, and the third bonding layer includes a second connection layer and a filling layer connected to the second connection layer;

[0033] The second connection layer is located on the surface of the first rewiring layer, the filling layer penetrates the first connection layer, and the filling layer is connected to the first barrier layer.

[0034] In some embodiments, the second MEMS device includes a second device structure, the second device structure includes a second sensitive surface and a second non-sensitive surface opposite to each other, and the second cavity is formed between the second sensitive surface and the cover plate.

[0035] In some embodiments, the second device structure includes a second sensitive region and a second lead-out region adjacent to each other, and the second cavity is disposed corresponding to the second sensitive region.

[0036] In some embodiments, the second MEMS device further includes a second pad, and the second pad is located on the second sensitive surface and in the second lead-out region.

[0037] In some embodiments, the second device structure further comprises:

[0038] A second sensitive structure, wherein the second sensitive structure has a second connecting through hole, and a side surface of the second sensitive structure is the second sensitive surface;

[0039] A second sacrificial layer is located on a side of the second sensitive structure close to the first device structure, and the second sacrificial layer has a fourth cavity therein, and the fourth cavity is connected to the second cavity through the second connecting through hole;

[0040] The second blocking layer is located on a side of the second sacrificial layer away from the second sensitive structure.

[0041] In some embodiments, the first MEMS device is a gyroscope sensor, and the second MEMS device is an acceleration sensor.

[0042] In some embodiments, the number of the first pads is greater than the number of the second pads.

[0043] According to a second aspect of the present application, a method for forming a MEMS packaging structure is provided, comprising:

[0044] forming a first MEMS device;

[0045] forming a second MEMS device;

[0046] forming a bonding structure on one side of the second MEMS device;

[0047] The second MEMS device is bonded to a side of the bonding structure away from the first MEMS device, and a first cavity is formed between the bonding structure and the first MEMS device.

[0048] In some embodiments, a method of forming a bonding structure on one side of the second MEMS device includes:

[0049] forming a second bonding layer on one side of the second MEMS device;

[0050] A first bonding layer is bonded to a side of the second bonding layer away from the second MEMS device.

[0051] In some embodiments, the method of bonding the first bonding layer on a side of the second bonding layer away from the second MEMS device includes:

[0052] Bonding an initial first bonding layer on a side of the second bonding layer away from the second MEMS device;

[0053] Thinning the initial first bonding layer;

[0054] A side of the initial first bonding layer away from the second bonding layer is etched to form the first bonding layer having a groove.

[0055] In some embodiments, a method of forming the first MEMS device includes:

[0056] Providing a substrate, and forming a first device structure on one side of the substrate;

[0057] forming a substrate on a side of the first device structure away from the substrate;

[0058] After forming the substrate, removing the base plate;

[0059] After removing the base plate, a first sub-sealing structure and a first pad are formed on a side of the first device structure away from the substrate.

[0060] In some embodiments, a method of bonding the second MEMS device to a side of the bonding structure away from the second MEMS device includes:

[0061] forming a second sub-sealing structure on a side of the first bonding layer close to the groove;

[0062] The first sub-sealing structure is bonded to the second sub-sealing structure to form a first cavity surrounded by the first sub-sealing structure, the second sub-sealing structure, the first bonding layer and the first device structure.

[0063] In some embodiments, a method of forming a first device structure on one side of the substrate includes:

[0064] forming an initial first sensitive structure, a first sacrificial layer and a first barrier layer stacked in sequence on the substrate;

[0065] Etching the first barrier layer and the first sacrificial layer to form a via hole exposing the initial first sensitive structure;

[0066] A first rewiring layer connected to the initial first sensitive structure is formed in the via hole and on the first barrier layer.

[0067] In some embodiments, the method of forming the first device structure further includes:

[0068] After removing the substrate, etching the initial first sensitive structure to form a first sensitive structure having a first connecting through hole;

[0069] The first sacrificial layer is etched through the first connecting through hole to form a third cavity, and the third cavity is connected with the first cavity through the first connecting through hole.

[0070] In some embodiments, the substrate includes a base and a stop layer, and the method of forming an initial first sensitive structure on the substrate includes:

[0071] A silicon-on-insulator is provided, the silicon-on-insulator comprising bottom silicon, top silicon and an insulating layer located between the top silicon and the bottom silicon, the bottom silicon serving as the substrate, the insulating layer serving as the stop layer, and the top silicon serving as the initial first sensitive structure.

[0072] In some embodiments, a method of forming a substrate on a side of the first device structure away from the substrate includes:

[0073] Forming a third bonding layer on a side of the first device structure away from the substrate, wherein the third bonding layer fills the routing pattern of the first rewiring layer;

[0074] performing a planarization process on the third bonding layer;

[0075] The substrate is bonded to a side of the third bonding layer away from the first redistribution layer.

[0076] In some embodiments, it also includes:

[0077] forming a third sub-sealing structure and a second pad spaced apart from each other on a side of the second MEMS device away from the first MEMS device;

[0078] providing a cover plate, and forming a fourth sub-sealing structure on one side of the cover plate;

[0079] The fourth sub-sealing structure is bonded to the third sub-sealing structure to form a second cavity surrounded by the cover plate, the third sub-sealing structure, the fourth sub-sealing structure and the second MEMS device.

[0080] According to a third aspect of the present application, there is provided a vehicle-mounted chip comprising the MEMS packaging structure described in any of the above embodiments.

[0081] According to a fourth aspect of the present application, a vehicle is also provided, comprising the MEMS packaging structure as described above.

[0082] The MEMS packaging structure of the embodiment of the present application includes a first MEMS device, a second MEMS device and a bonding structure, wherein the second MEMS device is bonded to the first MEMS device, the bonding structure is located between the first MEMS device and the second MEMS device, and a first cavity is formed between the bonding structure and the first MEMS device. Therefore, the first MEMS device and the second MEMS device can be stacked up and down through the bonding structure, thereby reducing the occupied area of ​​the packaging structure.

[0083] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0085] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings, wherein the same figure numbers represent the same parts in the following description.

[0086] Figure 1 is a schematic cross-sectional structure diagram of a MEMS packaging structure provided by some embodiments of the present application;

[0087] Figure 2 is a schematic diagram of a three-dimensional structure of a MEMS packaging structure provided by some embodiments of the present application;

[0088] Figure 3 is a schematic flow chart of a method for forming a MEMS packaging structure provided in some embodiments of the present application;

[0089] Figure 4 to Figure 25 is a schematic diagram of the structure of the MEMS packaging structure provided in some embodiments of the present application during the preparation process;

[0090] Fig.26 It is a schematic flow chart of a method for forming a first MEMS device provided in some embodiments of the present application. DETAILED DESCRIPTION

[0091] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0092] This application provides a MEMS packaging structure, please refer to Figure 1 , Figure 1 It is a schematic diagram of the cross-sectional structure of the MEMS packaging structure provided in some embodiments of the present application.

[0093] The MEMS packaging structure 100 includes a first MEMS device 10, a second MEMS device 20 and a bonding structure 30. The second MEMS device 20 is bonded to the first MEMS device 10. The bonding structure 30 is located between the first MEMS device 10 and the second MEMS device 20, and a first cavity C1 is formed between the bonding structure 30 and the first MEMS device 10. Therefore, the first MEMS device 10 and the second MEMS device 20 can be stacked up and down through the bonding structure 30, thereby reducing the occupied area of ​​the packaging structure.

[0094] The first MEMS device 10 and the second MEMS device 20 can both be capacitive (this application does not limit this) inertial sensors, and the capacitive inertial sensors can mainly include an electrode layer (including a fixed electrode and a movable electrode) and a wiring layer, the fixed electrode is used to detect the movement of the object, and when the object moves, the capacitance between the movable electrode and the fixed electrode will change, and the wiring layer is used to connect the electrical signal between the fixed electrode and the movable electrode. Since the capacitance value is proportional to the displacement, the change of the external environment can be inferred by measuring the change of capacitance. The first MEMS device 10 and the second MEMS device 20 can use the change of capacitance to detect and measure physical quantities such as acceleration, tilt, impact, vibration, rotation, etc.

[0095] In some embodiments, the bonding structure 30 may include a first bonding layer 31, the first bonding layer 31 includes a first surface 311 (i.e., the upper surface in the figure) and a second surface 312 (i.e., the lower surface in the figure) opposite to each other, the first surface 311 is in contact with the surface of the second MEMS device 20, and the second surface 312 and the first MEMS device 10 form the first cavity C1. The first cavity C1 can provide sufficient activity and movable space for the movable part of the first MEMS device 10, and can ensure that the device has sufficient degrees of freedom to move when working. The first cavity can be used to protect the first MEMS device 10 and prevent it from being affected by the external environment.

[0096] The first bonding layer 31 may have a groove C11 recessed relative to the second surface 312, and the groove constitutes a part of the first cavity C1. Specifically, the groove may constitute the upper part of the first cavity C1. Therefore, the design of the groove C11 may increase the space of the first cavity C1.

[0097] The MEMS packaging structure 100 may further include a first sealing structure 40, wherein the first sealing structure 40 is located between the first bonding layer 31 and the first MEMS device 10, wherein the second surface 312, the first sealing structure 40 and the first MEMS device 10 enclose the first cavity C1. The first sealing structure 40 may not only serve as a sealing member for the first cavity C1, but also as a bonding member for the second surface 312 and the first MEMS device 10.

[0098] The second surface 312 may be a flat surface, or may have a Figure 1 The opening of the groove is shown.

[0099] In some embodiments, the first sealing structure 40 may be made of metal or glass.

[0100] In some embodiments, the first sealing structure 40 may include a first sub-sealing structure 41 and a second sub-sealing structure 42, wherein the first sub-sealing structure 41 is located between the first MEMS device 10 and the second sub-sealing structure 42. The first sub-sealing structure 41 and the second sub-sealing structure 42 may be combined by bonding to achieve bonding between the first MEMS device 10 and the second surface 312.

[0101] The bonding structure 30 may further include a second bonding layer 32 bonded to the first bonding layer 31, and the second bonding layer 32 is located between the first bonding layer 31 and the second MEMS device 20. That is, the first MEMS device 10 and the second MEMS device 20 may be bonded by bonding the first bonding layer 31 and the second bonding layer 32. Specifically, the material of the first bonding layer 31 may include silicon, and the material of the second bonding layer 32 may include silicon oxide.

[0102] The first MEMS device 10 may include a first device structure 11, the first device structure 11 includes a first sensitive surface 101 and a first non-sensitive surface 102 opposite to each other, and the first cavity C1 is formed between the first sensitive surface 101 and the bonding structure 30. That is, the first sensitive surface 101 is in direct contact with the first cavity C1, so as to sense the movement of the object.

[0103] The first device structure 11 may include a first sensitive region 10a and a first lead-out region 10b, and the first cavity C1 is disposed corresponding to the first sensitive region 10a. Therefore, the first sensitive region 10a is used to sense the change of the motion state, and the first lead-out region 10b located outside the first cavity C1 may be used to lead out the pad.

[0104] The first sensitive region 10a and the first lead-out region 10b can be arranged adjacent to each other in the extension direction of the membrane layer (ie, the lateral direction shown in the figure). The first lead-out region 10b can be exposed on one side of the second MEMS device 20 (ie, extend beyond the second MEMS device 20) to facilitate the lead-out of electrical signals.

[0105] In a specific example, the first MEMS device 10 further includes a first pad 12, and the first pad 12 is located on the first sensitive surface 101 and in the first lead-out area 10b. Therefore, the first pad 12 can transmit electrical signals to the outside.

[0106] In some embodiments, the MEMS packaging structure 100 may include an integrated circuit structure (described in detail below), and the integrated circuit structure is electrically connected to the first pad 12 , so that the electrical signal of the first pad 12 is transmitted to the integrated circuit structure.

[0107] In some embodiments, the first pad 12 and the first sub-sealing structure 41 are made of the same material, for example, metal, so the first pad 12 can be manufactured together with the first sub-sealing structure 41 to reduce the process.

[0108] The MEMS packaging structure 100 may further include a third bonding layer 50 and a substrate 60. The third bonding layer 50 is located on the first non-sensitive surface 102 of the first device structure 11. The substrate 60 is bonded to a side of the third bonding layer 50 away from the first device structure 11. Therefore, the substrate 60 can play a supporting or bearing role in the entire packaging structure.

[0109] In some embodiments, the material of the third bonding layer 50 may include silicon dioxide, and the material of the substrate 60 may include silicon. Of course, the substrate 60 may also be other semiconductor substrates, which is not limited in the present application.

[0110] In some embodiments, the integrated circuit structure may be located within the substrate 60 , so that the substrate 60 may serve as an integrated chip and also serve as a carrier for the substrate 60 .

[0111] The MEMS packaging structure 100 may further include a cover plate 70 and a second sealing structure 80, wherein the cover plate 70 is located on a side of the second MEMS device 20 away from the first MEMS device 10, the second sealing structure 80 is located between the second MEMS device 20 and the cover plate 70, and a second cavity C2 is enclosed between the cover plate 70, the second sealing structure 80 and the second MEMS device 20. Therefore, the second cavity C2 serves as an active cavity of the second MEMS device 20.

[0112] That is, the cover plate 70 and the second MEMS device 20 may be combined via the second sealing structure 80 to form a second cavity C2. The cover plate 70 may have a groove C21 on one side close to the second sealing structure 80 to increase the volume of the second cavity C2.

[0113] In some embodiments, the second sealing structure 80 may be made of metal or glass.

[0114] In some embodiments, the second sealing structure 80 may include a third sub-sealing structure 81 and a fourth sub-sealing structure 82, wherein the third sub-sealing structure 81 is located between the second MEMS device 20 and the fourth sub-sealing structure 82. The third sub-sealing structure 81 and the fourth sub-sealing structure 82 may be combined by bonding to achieve bonding of the second MEMS device 20 to the cover plate 70.

[0115] The second MEMS device 20 may include a second device structure 21 . From the perspective of film layer stacking, the second device structure 21 includes a second sensitive surface 201 and a second non-sensitive surface 202 opposite to each other, and a second cavity C2 is formed between the second sensitive surface 201 and the cover plate 70 .

[0116] From the perspective of the film layer extension direction, the second device structure 21 may include adjacent second sensitive regions and second lead-out regions, and the second cavity C2 is disposed corresponding to the second sensitive region.

[0117] In some embodiments, the second sensitive area and the second lead-out area may be disposed adjacent to each other in the extension direction of the film layer (ie, the lateral direction shown in the figure). The second lead-out area may be exposed on one side of the cover plate 70 (ie, extend beyond the cover plate 70) to facilitate the lead-out of electrical signals.

[0118] Specifically, the second lead-out region can extend to the right side (in the direction shown in the figure) of the second MEMS device 20 beyond the cover plate 70, and the first lead-out region 10b can extend to the left side (in the direction shown in the figure) of the second MEMS device 20 beyond the second MEMS device 20, that is, the first lead-out region 10b and the second lead-out region are located on opposite sides of the cover plate 70. Therefore, signal lead-out can be performed on opposite sides respectively, so as to realize signal lead-out of the first MEMS device 10 and the second MEMS device 20 separately.

[0119] The second MEMS device 20 may further include a second pad 22 . The second pad 22 is located on the second sensitive surface 201 and in the second lead-out region. The second pad 22 may transmit the sensed electrical signal to the outside.

[0120] The specific structures of the first device structure 11 and the second device structure 21 will be described below.

[0121] The first device structure 11 further includes a first sensitive structure 111, a first sacrificial layer 112 and a first barrier layer 113. The first sensitive structure 111 has a first connecting through hole C12, and one side surface of the first sensitive structure 111 is the first sensitive surface 101. The first sacrificial layer 112 is located on a side of the first sensitive structure 111 away from the second MEMS device 20, and the first sacrificial layer 112 has a third cavity C13, and the third cavity C13 is connected to the first cavity C1 through the first connecting through hole C12, and the cavity formed by the connection serves as a complete active cavity of the first MEMS device 10. The first barrier layer 113 is located on a side of the first sacrificial layer 112 away from the first sensitive structure 111, and the first barrier layer 113 serves as a stop layer for etching the third cavity C13.

[0122] In some embodiments, the first sensitive structure 111 includes a fixed electrode and a movable electrode, such as Figure 1 As shown, a plurality of movable electrodes are arranged opposite to each other, and a first connecting through hole C12 is formed between two adjacent movable electrodes.

[0123] The first MEMS device 10 may further include a first rewiring layer 13 located on the first non-sensitive surface 102, the first rewiring layer 13 including a first connection layer 131 and a conductive plug 132 connected to the first connection layer 131. The first connection layer 131 is located on the first non-sensitive surface 102, the conductive plug 132 penetrates the first barrier layer 113 and the first sacrificial layer 112, and the conductive plug 132 is electrically connected to the first sensitive structure 111. Therefore, the first rewiring layer 13 can connect the internal signal of the first sensitive structure 111. Since the first pad 12 is also located on the first sensitive structure 111, the first rewiring layer 13 can lead the internal signal to the first pad 12.

[0124] The first connection layer 131 includes wiring patterns, and the wiring patterns are filled with insulating layers.

[0125] In some embodiments, the third bonding layer 50 is located on the side of the substrate 60 close to the first rewiring layer 13, that is, the first rewiring layer 13 is bonded to the substrate 60 through the third bonding layer 50. The third bonding layer 50 includes a second connection layer 51 and a filling layer 52 connected to the second connection layer 51. The second connection layer 51 is located on the surface of the first rewiring layer 13, the filling layer 52 penetrates the first connection layer 131, and the filling layer 52 is connected to the first barrier layer 113. Therefore, the third bonding layer 50 (specifically the second connection layer 51) can not only play the role of bonding the first connection layer 131 and the substrate 60, but also the third bonding layer 50 (specifically the filling layer 52) can fill the routing pattern of the first connection layer 131, playing the role of filling and insulation.

[0126] The second device structure 21 may include a second sensitive structure 211, a second sacrificial layer 212, and a second barrier layer 213. The second sensitive structure 211 has a second connecting through hole C22, and one side surface of the second sensitive structure 211 is the second sensitive surface 201. The second sacrificial layer 212 is located on a side of the second sensitive structure 211 close to the first device structure 11, and the second sacrificial layer 212 has a fourth cavity C23, and the fourth cavity C23 is connected to the second cavity C2 through the second connecting through hole C22, and the connected cavity serves as a complete active cavity of the second MEMS device 20. The second barrier layer 213 is located on a side of the second sacrificial layer 212 away from the second sensitive structure 211, and the second barrier layer 213 serves as a stop layer for etching the fourth cavity C23.

[0127] The second MEMS device 20 may further include a second rewiring layer 90, the second rewiring layer 90 being located on a side of the second barrier layer 213 away from the second sacrificial layer 212, the surface of the second rewiring layer 90 away from the second sensitive structure 211 being the second non-sensitive surface 202, and the second rewiring layer 90 being connected to the second sensitive structure 211. The connection method of the second rewiring layer 90 and the second sensitive structure 211 may be the same as the connection method of the first rewiring layer 13 and the first sensitive structure 111.

[0128] See also Figure 2 , Figure 2 It is a three-dimensional structural schematic diagram of a MEMS packaging structure provided in some embodiments of the present application.

[0129] The MEMS packaging structure 100 may further include an integrated chip 110 . The integrated chip 110 is located on a side of the cover plate 70 away from the first MEMS device 10 , and the integrated circuit structure is located inside the integrated chip 110 .

[0130] In some embodiments, the integrated chip 110 may include an Application-Specific Integrated Circuit (ASIC).

[0131] The first MEMS device 10 and the second MEMS device 20 are responsible for sensing signals and converting the measured quantities into changes in resistance, capacitance and other signals, while the integrated chip 110 is responsible for reading and processing these signals to eliminate interference and improve accuracy.

[0132] In some embodiments, the integrated chip 110 may include a third pad 110a and a fourth pad 110b, wherein the third pad 110a is connected to the first pad 12 through the first metal line (not shown), and the fourth pad 110b is connected to the second pad 22 through the second metal line (not shown).

[0133] In some embodiments, the first MEMS device 10 is a gyroscope sensor, and the second MEMS device 20 is an acceleration sensor.

[0134] It should be noted that the present application may also stack other different types of sensors, and the present application does not limit the type of MEMS devices.

[0135] In some embodiments, since the electrode structure of the gyroscope sensor is more complex than that of the acceleration sensor, the number of the first pads 12 is greater than the number of the second pads 22 .

[0136] According to a second aspect of the present application, a method for forming a MEMS packaging structure is provided. Figure 3 , Figure 3 1 is a flow chart of a method for forming a MEMS packaging structure provided in some embodiments of the present application, the forming method comprising:

[0137] Step S1: forming a first MEMS device 10 .

[0138] Step S2: forming a second MEMS device 20 .

[0139] Step S3 : forming a bonding structure 30 on one side of the second MEMS device 20 .

[0140] Step S4 : combining the second MEMS device 20 on a side of the combining structure 30 away from the first MEMS device 10 , so that a first cavity C1 is formed between the combining structure 30 and the first MEMS device 10 .

[0141] In the method for forming the MEMS packaging structure 100, the first MEMS device 10 and the second MEMS device 20 are first formed separately, and then the second MEMS device 20 is combined with the first MEMS device 10 through the bonding structure 30 to achieve up and down stacking, thereby reducing the area of ​​the packaging structure.

[0142] Please also see Figure 4 to Figure 25 , Figure 4 to Figure 25 1 is a schematic diagram of the structure of the MEMS packaging structure provided in some embodiments of the present application during the preparation process. This embodiment takes the preparation of the above-mentioned MEMS packaging structure 100 as an example to illustrate the formation method, so it can be combined with reference to Figure 1-2The method for forming the MEMS packaging structure 100 includes the following steps S1-S4.

[0143] Step S1: forming a first MEMS device 10 .

[0144] Step S2: forming a second MEMS device 20 .

[0145] For details, please see Figures 4 to 18 , Figures 4 to 18 The method for forming the first MEMS device 10 and the second MEMS device 20 separately is shown. The method for forming the first MEMS device 10 and the second MEMS device 20 is the same. The specific process of the MEMS device is described below by taking the formation of the first MEMS device 10 as an example.

[0146] In some embodiments, when the first MEMS device 10 is a gyroscope sensor and the second MEMS device 20 is an acceleration sensor, the first MEMS device 10 is formed as follows: Fig.17 As shown, the second MEMS device 20 finally formed is as shown in FIG. Fig.18 As shown (for the specific structure, see the description above), because Fig.17 The structure of the pads in the structure of the middle electrode layer is more.

[0147] See also Fig.26 , Fig.26 It is a schematic flow chart of a method for forming a first MEMS device provided in some embodiments of the present application. The method for forming the first MEMS device 10 includes steps S11 to S14.

[0148] Step S11: Provide a substrate 120, and form a first device structure 11 on one side of the substrate 120. Figures 4 to 9 .

[0149] In some embodiments, step S11 may include the following steps.

[0150] 1) An initial first sensitive structure 111', a first sacrificial layer 112 and a first barrier layer 113 are sequentially stacked on the substrate 120. For details, see Figures 4 to 6 First, an initial first sensitive structure 111 ′ is formed on the substrate 120 , and then a first sacrificial layer 112 and a first barrier layer 113 are sequentially formed on the initial first sensitive structure 111 ′ by a deposition process.

[0151] In some specific embodiments, the substrate 120 includes a base 120a and a stop layer 120b. The method of forming the initial first sensitive structure 111' on the substrate 120 includes: providing a silicon on insulator (SOI), the silicon on insulator including a bottom silicon, a top silicon and an insulating layer located between the top silicon and the bottom, the bottom silicon serving as the base 120a, the insulating layer serving as the stop layer 120b, and the top silicon serving as the initial first sensitive structure 111'. That is, the top silicon in the SOI can be used as the initial first sensitive structure 111'.

[0152] In some specific embodiments, the first sacrificial layer 112 may be formed by thermally oxidizing top silicon, and the material of the first sacrificial layer 112 includes silicon dioxide.

[0153] 2) Etching the first barrier layer 113 and the first sacrificial layer 112 to form a via hole 114 exposing the initial first sensitive structure 111'. Figure 7 The first barrier layer 113 and the first sacrificial layer 112 may be self-aligned and etched by an etching process to form a via hole 114 penetrating the first barrier layer 113 and the first sacrificial layer 112 .

[0154] 3) A first rewiring layer 13 connected to the initial first sensitive structure 111' is formed in the via hole 114 and on the first barrier layer 113. Figure 8-Figure 9 The initial first rewiring layer 13' can be deposited by a deposition process, and then an etching process is used to form a wiring pattern, that is, the first rewiring layer 13 is formed, so that the first rewiring layer 13 fills the via 114 and is connected to the initial first sensitive structure 111'. The material of the initial first rewiring can include low-resistance doped polysilicon, such as boron-doped polysilicon.

[0155] In the following text Fig.16 In the description, after the initial first sensitive structure 111' is prepared into the first sensitive structure 111, the first device structure 11 is formed.

[0156] Step S12: forming a substrate 60 on a side of the first device structure 11 away from the substrate 120. Figure 10 to Figure 12 .

[0157] In some embodiments, step S12 may include the following steps.

[0158] 1) A third bonding layer 50 is formed on a side of the first device structure 11 away from the substrate 120, and the third bonding layer 50 fills the wiring pattern of the first redistribution layer 13. For details, see Fig.10First, a third bonding layer 50 (eg, silicon dioxide) is deposited on the surface of the first redistribution layer 13 , and the initial third bonding layer 50 fills the routing pattern of the first redistribution layer 13 .

[0159] 2) The third bonding layer 50 is planarized. Fig.11 , the third bonding layer 50 may be planarized by using a chemical mechanical polishing process.

[0160] 3) Bonding the substrate 60 on the side of the third bonding layer 50 away from the first redistribution layer 13. Fig.12 , the substrate 60 can be bonded to the third bonding layer 50 by bonding.

[0161] Step S13: After forming the substrate 60, remove the base plate 120. Figure 13-14 .

[0162] Specifically, you can first Fig.12 The structure in the embodiment is flipped over, and then a chemical mechanical polishing process is first used to remove the substrate 120a and stop on the stop layer 120b, and then an etching process can be used to remove the stop layer 120b to expose the initial first sensitive structure 111'.

[0163] Step S14: After removing the substrate 120, a first sub-sealing structure 41 and a first pad 12 are formed on the side of the first device structure 11 away from the substrate 60. Fig.15 .

[0164] Specifically, the first sub-sealing structure 41 and the first pad 12 can be formed together by sputtering metal on the surface. When the first sub-sealing structure 41 and the first pad 12 are formed separately, the first sub-sealing structure 41 can be formed by sputtering glass paste, and the first pad 12 can be formed by sputtering metal.

[0165] In some embodiments, the steps of forming the first MEMS device 10 may further include: 1) referring to Fig.16 After removing the substrate 120, the initial first sensitive structure 111' is etched to form a first sensitive structure 111 having a first connecting through hole C12, thereby forming a first device structure 11; 2) See Fig.17 The first sacrificial layer 112 is etched through the first connecting through hole C12 to form a third cavity C13, and the third cavity C13 is connected to the first cavity C1 formed subsequently through the first connecting through hole C12.

[0166] like Fig.17As shown, the first MEMS device 10 is formed, and can also be referred to Figures 1 to 16 form Fig.18 The second MEMS device 20 shown in FIG. 1 is a schematic diagram of a second MEMS device 20. For a structural description of the second MEMS device 20, refer to FIG. Figure 1 , and will not be repeated here.

[0167] Step S3 : forming a bonding structure 30 on one side of the second MEMS device 20 .

[0168] In some embodiments, step S3 may include: 1) referring to Fig.18 , forming a second bonding layer 32 on one side of the second MEMS device 20; 2) referring to Fig.18 , bonding the initial first bonding layer 31' on the side of the second bonding layer 32 away from the second MEMS device 20; 3) referring to Fig.23 , the initial first bonding layer 31' is thinned; 4) see Fig.25 , etching the side of the initial first bonding layer 31 ′ away from the second bonding layer 32 to form the first bonding layer 31 having the groove C11.

[0169] In some embodiments, the method for forming the MEMS packaging structure 100 may further include: 1) referring to Fig.19 , providing a cover plate 70, and forming a fourth sub-sealing structure 82 on one side of the cover plate 70; 2) see Fig. 20 , the cover plate 70 is etched to form a groove C21; 3) see Figure 21-22 , the fourth sub-sealing structure 82 is bonded to the third sub-sealing structure 81 to form a second cavity C2 , and a portion of the cover plate 70 is removed to expose the second pad 22 .

[0170] Step S4 : combining the second MEMS device 20 on a side of the combining structure 30 away from the first MEMS device 10 , so that a first cavity C1 is formed between the combining structure 30 and the first MEMS device 10 .

[0171] In some embodiments, step S4 may include: 1) referring to Fig.24 , a second sub-sealing structure 42 is formed on one side of the first bonding layer 31 close to the groove C11; 2) see Figure 1 The first sub-sealing structure 41 is bonded to the second sub-sealing structure 42 to form a first cavity C1 surrounded by the first sub-sealing structure 41 , the second sub-sealing structure 42 , the first bonding layer 31 and the first device structure 11 .

[0172] The method for forming a MEMS packaging structure provided in the embodiment of the present application can stack the first MEMS device 10 and the second MEMS device 20 up and down through the bonding structure 30, thereby reducing the area of ​​the packaging structure.

[0173] According to the third aspect of the present application, a vehicle-mounted chip is provided, which includes the MEMS packaging structure in any of the above embodiments. The vehicle-mounted chip has all the beneficial effects of the above MEMS packaging structure, which will not be described in detail in the present application.

[0174] According to a fourth aspect of the present application, a vehicle is provided, which includes the on-board chip in any of the above embodiments. The vehicle has all the beneficial effects of the above-mentioned on-board chips, which will not be described in detail in the present application.

[0175] The vehicle may be a fuel vehicle, a plug-in hybrid vehicle or a new energy vehicle, etc., and this application does not make any specific limitation on this.

[0176] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0177] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0178] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0179] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A MEMS packaging structure, characterized in that: include: The first MEMS device; a second MEMS device, combined with the first MEMS device; The bonding structure is located between the first MEMS device and the second MEMS device, and a first cavity is formed between the bonding structure and the first MEMS device.

2. The MEMS packaging structure according to claim 1, characterized in that: The bonding structure includes a first bonding layer, the first bonding layer includes a first surface and a second surface opposite to each other, the first surface contacts the surface of the second MEMS device, and the second surface and the first MEMS device form the first cavity.

3. The MEMS packaging structure according to claim 2, characterized in that: The first bonding layer has a groove recessed relative to the second surface, and the groove constitutes a part of the first cavity.

4. The MEMS packaging structure according to claim 2 or 3, characterized in that: Also includes: The first sealing structure is located between the first bonding layer and the first MEMS device. The first sealing structure, the second surface and the first MEMS device form the first cavity.

5. The MEMS packaging structure according to claim 2, characterized in that: The bonding structure further includes a second bonding layer bonded to the first bonding layer, and the second bonding layer is located between the first bonding layer and the second MEMS device.

6. The MEMS packaging structure according to claim 1, characterized in that: The first MEMS device includes a first device structure, the first device structure includes a first sensitive surface and a first non-sensitive surface opposite to each other, and the first cavity is formed between the first sensitive surface and the bonding structure.

7. The MEMS packaging structure according to claim 6, characterized in that: The first device structure includes a first sensitive region and a first lead-out region, and the first cavity is arranged corresponding to the first sensitive region.

8. The MEMS packaging structure according to claim 7, characterized in that: The first MEMS device further includes a first pad, which is located on the first sensitive surface and in the first lead-out region.

9. The MEMS packaging structure according to claim 8, characterized in that: Also included is an integrated circuit structure electrically connected to the first pad.

10. The MEMS packaging structure according to claim 9, characterized in that: Also includes: a cover plate, located at a side of the second MEMS device away from the first MEMS device; The second sealing structure is located between the second MEMS device and the cover plate, and a second cavity is formed between the cover plate, the second sealing structure and the second MEMS device.

11. The MEMS packaging structure according to claim 10, characterized in that: Also includes: An integrated chip is located on a side of the cover plate away from the first MEMS device, and the integrated circuit structure is located in the integrated chip.

12. The MEMS packaging structure according to claim 9, characterized in that: Also includes: a third bonding layer, located on the first non-sensitive surface of the first device structure; A substrate is bonded to a side of the third bonding layer away from the first device structure.

13. The MEMS packaging structure according to claim 12, characterized in that: The integrated circuit structure is located within the substrate.

14. The MEMS packaging structure according to claim 12, characterized in that: The first device structure further includes: A first sensitive structure, wherein the first sensitive structure has a first connecting through hole, and a side surface of the first sensitive structure is the first sensitive surface; a first sacrificial layer, located on a side of the first sensitive structure away from the second MEMS device, and having a third cavity in the first sacrificial layer, wherein the third cavity is connected to the first cavity through the first connecting through hole; The first barrier layer is located on a side of the first sacrificial layer away from the first sensitive structure.

15. The MEMS packaging structure according to claim 14, characterized in that: The first MEMS device further includes a first rewiring layer located on the first non-sensitive surface, the first rewiring layer including a first connection layer and a conductive plug connected to the first connection layer; The first connection layer is located on the first non-sensitive surface, the conductive plug penetrates the first barrier layer and the first sacrificial layer, and the conductive plug is electrically connected to the first sensitive structure.

16. The MEMS packaging structure according to claim 15, characterized in that: The third bonding layer is located at a side of the substrate close to the first rewiring layer, and the third bonding layer includes a second connection layer and a filling layer connected to the second connection layer; The second connection layer is located on the surface of the first rewiring layer, the filling layer penetrates the first connection layer, and the filling layer is connected to the first barrier layer.

17. The MEMS packaging structure according to claim 10, characterized in that: The second MEMS device includes a second device structure, the second device structure includes a second sensitive surface and a second non-sensitive surface opposite to each other, and the second cavity is formed between the second sensitive surface and the cover plate.

18. The MEMS packaging structure according to claim 17, characterized in that: The second device structure includes a second sensitive region and a second lead-out region adjacent to each other, and the second cavity is arranged corresponding to the second sensitive region.

19. The MEMS packaging structure according to claim 18, characterized in that: The second MEMS device further includes a second pad, which is located on the second sensitive surface and in the second lead-out area.

20. The MEMS packaging structure according to claim 17, characterized in that: The second device structure further includes: A second sensitive structure, wherein the second sensitive structure has a second connecting through hole, and a side surface of the second sensitive structure is the second sensitive surface; A second sacrificial layer is located on a side of the second sensitive structure close to the first device structure, and the second sacrificial layer has a fourth cavity therein, and the fourth cavity is connected to the second cavity through the second connecting through hole; The second blocking layer is located on a side of the second sacrificial layer away from the second sensitive structure.

21. The MEMS packaging structure according to claim 1, characterized in that: The first MEMS device is a gyroscope sensor, and the second MEMS device is an acceleration sensor.

22. The MEMS packaging structure according to claim 19, characterized in that: The number of the first pads is greater than the number of the second pads.

23. A method for forming a MEMS packaging structure, characterized in that: include: forming a first MEMS device; forming a second MEMS device; forming a bonding structure on one side of the second MEMS device; The second MEMS device is bonded to a side of the bonding structure away from the first MEMS device, and a first cavity is formed between the bonding structure and the first MEMS device.

24. The method for forming a MEMS packaging structure according to claim 23, characterized in that: The method of forming a bonding structure on one side of the second MEMS device includes: forming a second bonding layer on one side of the second MEMS device; A first bonding layer is bonded to a side of the second bonding layer away from the second MEMS device.

25. The method for forming a MEMS packaging structure according to claim 24, characterized in that: The method of bonding the first bonding layer on a side of the second bonding layer away from the second MEMS device includes: Bonding an initial first bonding layer on a side of the second bonding layer away from the second MEMS device; Thinning the initial first bonding layer; A side of the initial first bonding layer away from the second bonding layer is etched to form the first bonding layer having a groove.

26. The method for forming a MEMS packaging structure according to claim 25, characterized in that: The method of forming the first MEMS device includes: Providing a substrate, and forming a first device structure on one side of the substrate; forming a substrate on a side of the first device structure away from the substrate; After forming the substrate, removing the base plate; After removing the base plate, a first sub-sealing structure and a first pad are formed on a side of the first device structure away from the substrate.

27. The method for forming a MEMS packaging structure according to claim 26, characterized in that: The method of bonding the second MEMS device to a side of the bonding structure away from the second MEMS device includes: forming a second sub-sealing structure on a side of the first bonding layer close to the groove; The first sub-sealing structure is bonded to the second sub-sealing structure to form a first cavity surrounded by the first sub-sealing structure, the second sub-sealing structure, the first bonding layer and the first device structure.

28. The method for forming a MEMS packaging structure according to claim 27, characterized in that: The method of forming a first device structure on one side of the substrate includes: forming an initial first sensitive structure, a first sacrificial layer and a first barrier layer stacked in sequence on the substrate; Etching the first barrier layer and the first sacrificial layer to form a via hole exposing the initial first sensitive structure; A first rewiring layer connected to the initial first sensitive structure is formed in the via hole and on the first barrier layer.

29. The method for forming a MEMS packaging structure according to claim 28, characterized in that: The method of forming the first device structure further includes: After removing the substrate, etching the initial first sensitive structure to form a first sensitive structure having a first connecting through hole; The first sacrificial layer is etched through the first connecting through hole to form a third cavity, and the third cavity is connected with the first cavity through the first connecting through hole.

30. The method for forming a MEMS packaging structure according to claim 28, characterized in that: The substrate comprises a base and a stop layer, and the method for forming an initial first sensitive structure on the substrate comprises: A silicon-on-insulator is provided, wherein the silicon-on-insulator comprises bottom silicon, top silicon and an insulating layer located between the top silicon and the bottom silicon, wherein the bottom silicon serves as the substrate, the insulating layer serves as the stop layer, and the top silicon serves as the initial first sensitive structure.

31. The method for forming a MEMS packaging structure according to claim 28, characterized in that: The method of forming a substrate on a side of the first device structure away from the substrate includes: Forming a third bonding layer on a side of the first device structure away from the substrate, wherein the third bonding layer fills the routing pattern of the first rewiring layer; performing a planarization process on the third bonding layer; The substrate is bonded to a side of the third bonding layer away from the first redistribution layer.

32. The method for forming a MEMS packaging structure according to claim 28, characterized in that: Also includes: forming a third sub-sealing structure and a second pad spaced apart from each other on a side of the second MEMS device away from the first MEMS device; providing a cover plate, and forming a fourth sub-sealing structure on one side of the cover plate; The fourth sub-sealing structure is bonded to the third sub-sealing structure to form a second cavity surrounded by the cover plate, the third sub-sealing structure, the fourth sub-sealing structure and the second MEMS device.

33. A vehicle-mounted chip, characterized in that: It comprises the MEMS packaging structure as described in claims 1 to 22.

34. A vehicle, characterized in that: Including the vehicle-mounted chip as described in claim 33.

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