Method for manufacturing MEMS packaging structure

Abstract

A method for manufacturing a MEMS packaging structure, the method comprising: respectively forming a micro vacuum gauge (300) and a vacuum degree control unit (400) on first and second substrates (100, 200), and respectively forming first and second recesses (103, 104) and third and fourth recesses (203, 204) in the first and second substrates (100, 200), wherein the micro vacuum gauge (300) is suspended above the first recess (103), and the vacuum degree control unit (400) is suspended above the fourth recess (204); and then bonding the first and second substrates (100, 200) to form a sealed micro vacuum cavity (500), wherein the sealed micro vacuum cavity (500) comprises a first vacuum cavity (501), a gas molecule flow channel (502) and a second vacuum cavity (503) which are in communication in sequence, and the micro vacuum gauge (300) and the vacuum degree control unit (400) are respectively located in the first and second vacuum cavities (501, 503) and are respectively configured to monitor and regulate the internal vacuum degree of the sealed micro vacuum cavity (500). By means of the manufacturing method, the micro vacuum gauge and the vacuum degree control unit are integrated in the same micro vacuum cavity, such that the internal vacuum degree of the micro vacuum cavity where microelectronic devices are located can be simultaneously monitored and controlled in real time; and the manufacturing method involves a simple process and achieves high compatibility.

Description

Manufacturing method of MEMS packaging structure TECHNICAL FIELD

[0001] The present application belongs to the field of MEMS device integrated design and manufacturing, and relates to a manufacturing method of MEMS packaging structure. BACKGROUND

[0002] Micro-Electro Mechanical System (MEMS) is a technology for processing in micro-nano scale, and is a high value-added element by integrating micro-mechanical parts, electronic circuits, traditional sensors, actuators and the like on a circuit board. Different packaging processes can integrate multiple sensors with different functions, different sensitivities or actuating directions into one, form a micro-sensor array, and even integrate devices with multiple functions together to form a complex micro system. The integration of micro sensors and micro electronic devices can manufacture a series of MEMS devices with strong reliability and stability. Nowadays, the MEMS manufacturing process tends to integrate more functions in a single MEMS chip to achieve higher integration.

[0003] The development direction of MEMS sensors is array, intelligence and integration. MEMS integrated devices are extremely sensitive to the packaging environment, and the dramatic changes of some key indicators will cause the frequency drift of MEMS devices and then cause failure. In practice, the internal vacuum degree of the vacuum microcavity formed by packaging MEMS devices will decrease with time, which often leads to the decline of the performance indicators of the packaged devices, that is, the output signal of such devices will change from time to time, so that the measurement results of the devices cannot well reflect the measured physical quantity; at the same time, the service life of the devices will also decrease.

[0004] Therefore, how to provide a manufacturing method of MEMS packaging structure to simultaneously meet the real-time monitoring and control of the internal vacuum degree of the micro vacuum cavity when vacuum packaging the MEMS device has become an important technical problem to be solved by the person skilled in the art.

[0005] It should be noted that the above introduction to the technical background is only to facilitate the clear and complete description of the technical scheme of the present application, and to facilitate the understanding of the person skilled in the art. The above technical scheme cannot be considered as known to the person skilled in the art only because it is described in the background section of the present application.

[0006] SUMMARY

[0007] In view of the above-mentioned defects of the prior art, the purpose of the present application is to provide a manufacturing method of a MEMS packaging structure, which is used to solve the problem that the real-time monitoring and control of the internal vacuum degree of the micro-vacuum cavity cannot be simultaneously satisfied when the MEMS device is vacuum packaged in the prior art.

[0008] To achieve the above-mentioned purpose and other related purposes, the present application provides a manufacturing method of a MEMS packaging structure, comprising the following steps:

[0009] A first substrate and a second substrate are provided, the first substrate has a first main surface and a second main surface arranged oppositely, and the second substrate has a first main surface and a second main surface arranged oppositely;

[0010] A micro-vacuum gauge is formed on the first main surface of the first substrate, and a vacuum degree control unit is formed on the first main surface of the second substrate;

[0011] A first recessed cavity and a second recessed cavity are formed on the first main surface of the first substrate and are spaced from each other, and the micro-vacuum gauge is suspended above the first recessed cavity; a third recessed cavity and a fourth recessed cavity are formed on the first main surface of the second substrate and are spaced from each other, and the vacuum degree control unit is suspended above the fourth recessed cavity;

[0012] The first main surface of the second substrate and the first main surface of the first substrate are arranged to face each other and are bonded to form a sealed micro-vacuum cavity, the sealed micro-vacuum cavity comprises a first vacuum cavity, a gas molecule flow passage and a second vacuum cavity which are sequentially communicated, the first vacuum cavity is composed of the first recessed cavity and the third recessed cavity, the second vacuum cavity is composed of the second recessed cavity and the fourth recessed cavity, the first substrate and the second substrate are spaced apart by a certain distance in the region between the first vacuum cavity and the second vacuum cavity to define the gas molecule flow passage, the micro-vacuum gauge is used to monitor the internal vacuum degree of the sealed micro-vacuum cavity, and the vacuum degree control unit is used to adjust the internal vacuum degree of the sealed micro-vacuum cavity.

[0013] Optionally, the following steps are included:

[0014] A first insulating layer is formed on the first main surface of the first substrate;

[0015] The micro-vacuum gauge is formed on the first insulating layer;

[0016] A first etching window and a second etching window penetrating through the first insulating layer are formed;

[0017] etching the first substrate via the first etching window and the second etching window to obtain the first cavity and the second cavity, wherein a portion of the first insulating layer is suspended above the first cavity as a first support layer, the first support layer comprising a first support main body and at least one first support arm, one end of the first support arm being connected to the first support main body and the other end being connected to a rigid portion of the first substrate, the micro vacuum gauge being arranged on a side of the first support main body facing away from the first cavity.

[0018] Optionally, the method comprises the following steps:

[0019] forming a vacuum gauge circuit material layer on the first insulating layer;

[0020] patterning the vacuum gauge circuit material layer to obtain the micro vacuum gauge and a first lead-out portion electrically connected to the micro vacuum gauge, the first lead-out portion extending through a region where the first support arm is located and beyond a region where the sealed micro vacuum cavity is located;

[0021] forming a second insulating layer covering the micro vacuum gauge and the first lead-out portion;

[0022] forming a first contact hole exposing the first lead-out portion in the second insulating layer;

[0023] forming a first electrode material layer on the second insulating layer, the first electrode material layer being filled into the first contact hole;

[0024] patterning the first electrode material layer to obtain a first wire-bonding pad electrically connected to the first lead-out portion and a second wire-bonding pad for electrical connection with the vacuum degree control unit, the first wire-bonding pad and the second wire-bonding pad both being arranged beyond the region where the sealed micro vacuum cavity is located;

[0025] forming a third insulating layer covering the first wire-bonding pad and the second wire-bonding pad on the second insulating layer;

[0026] forming the first etching window and the second etching window penetrating through the third insulating layer, the second insulating layer and the first insulating layer;

[0027] etching the first substrate via the first etching window and the second etching window to obtain the first cavity and the second cavity;

[0028] removing the third insulating layer.

[0029] Optionally, the first bonding portion for bonding with the second substrate is obtained when the first electrode material layer is patterned to obtain the first wire-bonding pad electrically connected with the first lead-out portion and the second wire-bonding pad for electrically connecting with the vacuum degree control unit.

[0030] Optionally, the method further comprises the following steps:

[0031] forming a fourth insulating layer on the first main surface of the second substrate;

[0032] forming the vacuum degree control unit on the fourth insulating layer;

[0033] forming a third etching window and a fourth etching window through the fourth insulating layer;

[0034] etching the second substrate through the third etching window and the fourth etching window to obtain the third cavity and the fourth cavity, wherein a portion of the fourth insulating layer is suspended above the fourth cavity as a second support layer, the second support layer comprises a second support main body portion and at least one second support arm, one end of the second support arm is connected to the second support main body portion, and the other end of the second support arm is connected to a rigid portion of the second substrate, and the vacuum degree control unit is arranged on a side of the second support main body portion away from the fourth cavity.

[0035] Optionally, the method further comprises the following steps:

[0036] forming a thin-film heater material layer on the fourth insulating layer;

[0037] patterning the thin-film heater material layer to obtain a thin-film heater and a second lead-out portion electrically connected with the thin-film heater, the second lead-out portion passes through a region where the second support arm is located and extends to a region outside the sealed micro-vacuum cavity;

[0038] forming a fifth insulating layer covering the thin-film heater and the second lead-out portion;

[0039] forming a second contact hole exposing the second lead-out portion in the fifth insulating layer;

[0040] forming a second electrode material layer on the fifth insulating layer, the second electrode material layer being filled into the second contact hole;

[0041] patterning the second electrode material layer to obtain a connection pad electrically connected with the second lead-out portion;

[0042] forming a sixth insulating layer covering the connection pad on the fifth insulating layer;

[0043] forming the third etching window and the fourth etching window through the sixth insulating layer, the fifth insulating layer and the fourth insulating layer;

[0044] etching the second substrate through the third etching window and the fourth etching window to obtain the third cavity and the fourth cavity;

[0045] removing the sixth insulating layer;

[0046] forming a getter film above the thin-film heater, the getter film and the thin-film heater being separated by the fifth insulating layer.

[0047] Optionally, when the second electrode material layer is patterned to obtain a connection pad electrically connected with the second lead-out part, a second bonding part for bonding with the first substrate is also obtained.

[0048] Optionally, forming a getter film above the thin-film heater comprises the following steps:

[0049] covering the second substrate with a metal mask, the metal mask being provided with a deposition window above the fourth cavity;

[0050] depositing the getter film on the fifth insulating layer based on the deposition window;

[0051] removing the metal mask.

[0052] Optionally, the micro vacuum gauge comprises a MEMS Pirani vacuum gauge.

[0053] Optionally, the gas molecule flow channel has a shape of a circle or a polygon in a normal projection on a plane in which the first substrate is located, and a height of the gas molecule flow channel ranges from 1.5 microns to 50 microns.

[0054] Optionally, the method further comprises the step of forming a MEMS sensor, the MEMS sensor being arranged in the first vacuum cavity or the second vacuum cavity, and the MEMS sensor comprising one or more of a MEMS accelerometer, a MEMS pressure sensor and a MEMS gyroscope.

[0055] As described above, the manufacturing method of the MEMS packaging structure of the present application forms a micro vacuum gauge on the first main surface of the first substrate, forms a vacuum degree control unit on the first main surface of the second substrate, and forms a first recessed cavity and a second recessed cavity spaced apart from each other on the first main surface of the first substrate, and forms a third recessed cavity and a fourth recessed cavity spaced apart from each other on the first main surface of the second substrate, wherein the micro vacuum gauge is suspended above the first recessed cavity, the vacuum degree control unit is suspended above the fourth recessed cavity, and then the first main surface of the second substrate and the first main surface of the first substrate are arranged to face each other and bonded to form a sealed micro vacuum cavity, which includes a first vacuum cavity, a gas molecule flow passage and a second vacuum cavity connected in sequence, the micro vacuum gauge is located in the first vacuum cavity for monitoring the internal vacuum degree of the sealed micro vacuum cavity, and the vacuum degree control unit is located in the second vacuum cavity for adjusting the internal vacuum degree of the sealed micro vacuum cavity. The manufacturing method of the MEMS packaging structure of the present application integrates the micro vacuum gauge and the vacuum degree control unit in the same micro vacuum cavity, which can realize the real-time monitoring and real-time control of the internal vacuum degree of the micro vacuum cavity where the microelectronic device is located at the same time, and the manufacturing method has the advantages of simple process and high compatibility. BRIEF DESCRIPTION OF DRAWINGS

[0056] FIG. 1 shows a process flow diagram of the manufacturing method of the MEMS packaging structure of the present application.

[0057] FIG. 2a shows a schematic diagram of the first substrate provided in an embodiment of the manufacturing method of the MEMS packaging structure of the present application.

[0058] FIG. 2b shows a schematic diagram of the second substrate provided in an embodiment of the manufacturing method of the MEMS packaging structure of the present application.

[0059] FIG. 3 shows a schematic diagram of the structure obtained after forming a first insulating layer on the surface of the first substrate in an embodiment of the manufacturing method of the MEMS packaging structure of the present application.

[0060] FIG. 4 shows a schematic diagram of the structure obtained after forming a vacuum gauge circuit material layer on the first insulating layer in an embodiment of the manufacturing method of the MEMS packaging structure of the present application.

[0061] FIG. 5 shows a schematic diagram of the structure obtained after patterning the vacuum gauge circuit material layer to obtain a micro vacuum gauge and a first lead-out part in an embodiment of the manufacturing method of the MEMS packaging structure of the present application.

[0062] FIG. 6 shows a schematic diagram of the structure obtained after forming a second insulating layer covering the micro vacuum gauge and a lead-out part in an embodiment of the manufacturing method of the MEMS packaging structure of the present application.

[0063] Figure 7 shows a schematic diagram of the structure obtained after forming a first contact hole in the second insulating layer to expose the first lead-out portion in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0064] Figure 8 shows a schematic diagram of the structure obtained after forming a first electrode material layer on the second insulating layer in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0065] Figure 9 shows a schematic diagram of the structure obtained after patterning the first electrode material layer to obtain a first wire-bonding pad, a second wire-bonding pad and a first bonding portion in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0066] Figure 10 shows a schematic diagram of the structure obtained after forming a third insulating layer on the second insulating layer to cover the first wire-bonding pad and the second wire-bonding pad in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0067] Figure 11 shows a schematic diagram of the structure obtained after forming a first etching window and a second etching window through the third insulating layer, the second insulating layer and the first insulating layer in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0068] Figure 12 shows a schematic diagram of the structure obtained after etching the first substrate to obtain a first cavity and a second cavity in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0069] Figure 13 shows a schematic diagram of the structure obtained after removing the third insulating layer in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0070] Figure 14 shows a schematic diagram of the structure obtained after forming a fourth insulating layer on the surface of the second substrate in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0071] Figure 15 shows a schematic diagram of the structure obtained after forming a thin-film heater material layer in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0072] Figure 16 shows a schematic diagram of the structure obtained after patterning the thin-film heater material layer to obtain a thin-film heater and a second lead-out portion in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0073] Figure 17 shows a schematic diagram of the structure obtained after forming a fifth insulating layer in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0074] Figure 18 shows a schematic diagram of the structure obtained after forming a second contact hole in one embodiment of the method of fabricating the MEMS package structure of the present application.

[0075] Figure 19 shows a schematic diagram of the structure obtained after forming a second electrode material layer in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0076] Figure 20 shows a schematic diagram of the structure obtained after patterning the second electrode material layer to obtain a connection pad and a second bonding portion in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0077] Figure 21 shows a schematic diagram of the structure obtained after forming a sixth insulating layer in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0078] Figure 22 shows a schematic diagram of the structure obtained after forming a third etching window and a fourth etching window in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0079] Figure 23 shows a schematic diagram of the structure obtained after etching the second substrate to obtain a third cavity and a fourth cavity in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0080] Figure 24 shows a schematic diagram of the structure obtained after removing the sixth insulating layer in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0081] Figure 25 shows a schematic diagram of the structure obtained after depositing a getter film through a metal mask in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0082] Figure 26 shows a schematic diagram of the structure obtained after removing the metal mask in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0083] Figure 27 shows a schematic diagram of the structure obtained after bonding the first and second substrates in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0084] Figure 28 shows a schematic diagram of the structure obtained after etching the second substrate after bonding is completed in an embodiment of the method of fabricating a MEMS package structure of the present application.

[0085] Figure 29 shows a plan layout of the first support layer, the micro vacuum gauge, the first lead-out portion and the structures therearound in an embodiment.

[0086] Figure 30 shows a plan layout of the first support layer, the micro vacuum gauge, the first lead-out portion and the structures therearound in another embodiment.

[0087] Legend of reference signs

[0088] S1-S4 step

[0089] 100 first substrate

[0090] 101 first main surface

[0091] 102 second main surface

[0092] 103 first cavity

[0093] 104 second cavity

[0094] 105 first insulating layer

[0095] 105a first support layer

[0096] 1051a first support main body portion

[0097] 1052a first support arm

[0098] 106 vacuum gauge circuit material layer

[0099] 107 first lead-out portion

[0100] 1071 lead-out wire

[0101] 1072 lead-out disc

[0102] 108 second insulating layer

[0103] 109 first contact hole

[0104] 110 first electrode material layer

[0105] 111 first wire-bonding pad

[0106] 112 second wire-bonding pad

[0107] 113 first bonding portion

[0108] 114 third insulating layer

[0109] 115 first etching window

[0110] 116 second etching window

[0111] 200 second substrate

[0112] 201 first main surface

[0113] 202 second main surface

[0114] 203 third cavity

[0115] 204 fourth cavity

[0116] 205 fourth insulating layer

[0117] 205a second support layer

[0118] 206 thin-film heater material layer

[0119] 207 thin-film heater

[0120] 208 second lead-out portion

[0121] 209 fifth insulating layer

[0122] 210 second contact hole

[0123] 211 second electrode material layer

[0124] 212 connection pad

[0125] 213 Second bonding portion

[0126] 214 Sixth insulating layer

[0127] 215 Third etching window

[0128] 216 Fourth etching window

[0129] 217 Alignment bolt

[0130] 218 Suction agent film

[0131] 219 Metal mask

[0132] 220 Deposition window

[0133] 300 Micro vacuum gauge

[0134] 400 Vacuum degree control unit

[0135] 500 Closed micro vacuum cavity

[0136] 501 First vacuum cavity

[0137] 502 Gas molecule flow passage

[0138] 503 Second vacuum cavity DETAILED DESCRIPTION

[0139] The present application is herein described, by way of example only, with the

[0140] It should be emphasized that the term "comprises / comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0141] Features described and / or illustrated for one implementation can be used in the same or similar manner in one or more other implementations, in combination with or in place of features in the other implementations.

[0142] As described in the detailed description of embodiments of the application, to facilitate an understanding of the present application, illustrative views are shown in partial section, which are not necessarily to scale, and are shown in schematic form. The illustrative views are not intended to limit the scope of the present application as it is to be limited only by the claims. Furthermore, the actual dimensions of the various components can be different from that shown in the figures.

[0143] To facilitate an understanding of the present application, various illustrative embodiments are described and / or illustrated in the detailed description of embodiments of the application. It should be understood that features of the various embodiments described and / or illustrated in the detailed description of embodiments of the application can be combined with each other, unless specifically stated otherwise.

[0144] In the context of this application, a structure described as being "on" another structure can comprise embodiments in which the structures are in direct contact, and embodiments in which one or more further structures are interposed between the structures.

[0145] It should be noted that the drawings provided herein are merely schematic and are not drawn to scale. Certain features of the drawings can be exaggerated for the purpose of illustration and description.

[0146] Referring to FIG. 1, a process flow diagram of a method for manufacturing a MEMS packaging structure is shown, including the following steps:

[0147] S1: providing a first substrate and a second substrate, the first substrate having a first main surface and a second main surface arranged opposite to each other, and the second substrate having a first main surface and a second main surface arranged opposite to each other;

[0148] S2: forming a micro vacuum gauge on the first main surface of the first substrate, and forming a vacuum degree control unit on the first main surface of the second substrate;

[0149] S3: forming a first cavity and a second cavity spaced apart from each other on the first main surface of the first substrate and suspending the micro vacuum gauge above the first cavity, and forming a third cavity and a fourth cavity spaced apart from each other on the first main surface of the second substrate and suspending the vacuum degree control unit above the fourth cavity;

[0150] S4: disposing and bonding the first main surface of the second substrate and the first main surface of the first substrate to face each other to form a sealed micro vacuum cavity, the sealed micro vacuum cavity comprising a first vacuum cavity, a gas molecule flow passage and a second vacuum cavity connected in sequence, the first vacuum cavity being composed of the first cavity and the third cavity, the second vacuum cavity being composed of the second cavity and the fourth cavity, the first substrate and the second substrate being spaced apart by a distance in the region between the first vacuum cavity and the second vacuum cavity to define the gas molecule flow passage, the micro vacuum gauge being used to monitor the internal vacuum degree of the sealed micro vacuum cavity, and the vacuum degree control unit being used to adjust the internal vacuum degree of the sealed micro vacuum cavity.

[0151] It should be noted that the order of the above steps S2 and S3 is not limited in the present application, for example, the second substrate can be processed at the same time when the first substrate is processed.

[0152] The above steps will be described in detail below in combination with the drawings.

[0153] First, refer to FIGS. 2a and 2b, the step S1 is performed: providing a first substrate 100 (as shown in FIG. 2a) and a second substrate 200 (as shown in FIG. 2b), the first substrate 100 has a first main surface 101 and a second main surface 102 disposed opposite to each other, and the second substrate 200 has a first main surface 201 and a second main surface 202 disposed opposite to each other.

[0154] As an example, the first substrate 100 and the second substrate 200 can be selected from wafers commonly used in the field of semiconductor manufacturing, such as silicon wafers, silicon on insulator (SOI), germanium silicon wafers, germanium wafers, gallium nitride wafers, SiC wafers, etc., or insulating wafers such as quartz, sapphire, glass, etc.

[0155] In some embodiments, the first substrate 100 and the second substrate 200 include wafers and semiconductor devices fabricated on the surface of the wafers, and include various thin films and various structures required for MEMS devices.

[0156] In a specific example, the first substrate 100 and the second substrate 200 are both selected from silicon substrates with a thickness greater than 200 microns and less than 700 microns, and a diameter of about 200 millimeters.

[0157] Next, the step S2 and the step S3 are executed. For the convenience of description, the processing part related to the first substrate 100 and the processing part related to the second substrate 200 will be described separately.

[0158] As an example, referring to FIGS. 3 to 13, the process of forming a micro vacuum gauge 300 on the first main surface 101 of the first substrate 100 and forming a first recessed cavity 103 and a second recessed cavity 104 spaced apart from each other on the first main surface 101 of the first substrate 100 and suspending the micro vacuum gauge 300 above the first recessed cavity 103 in an embodiment is shown as follows:

[0159] (1) As shown in FIG. 3, a first insulating layer 105 is formed on the first main surface 101 of the first substrate 100.

[0160] Specifically, the first insulating layer 105 has two main functions: one is to shield the material of the micro vacuum gauge test circuit formed subsequently from the material of the first substrate 100; and the other is to support the micro vacuum gauge test circuit. The specific material and thickness of the first insulating layer 105 can be designed according to the required performance of the micro vacuum gauge test circuit.

[0161] As an example, the first insulating layer 105 can be a single-material thin film, a composite thin film composed of multiple materials, or a composite thin film formed by laminating multiple single-material thin films.

[0162] In an embodiment, the first insulating layer 105 is a single thin film composed of silicon nitride, and the thickness is 0.5 microns.

[0163] In an embodiment, the first substrate 100 is a silicon substrate, and the first insulating layer 105 is formed on the surface of the first substrate 100 by using a conventional low pressure chemical vapor deposition (LPCVD) and its supporting process, wherein the first main surface 101 and the second main surface 102 of the first substrate 100 are both deposited with an insulating layer.

[0164] (2) As shown in FIG. 4, a vacuum gauge circuit material layer 106 is formed on the first insulating layer 105.

[0165] As an example, the vacuum gauge circuit material layer 106 is a 0.2-micron-thick metal Ti layer formed by using a conventional magnetron sputtering and its supporting process.

[0166] (3) As shown in FIG. 5, the vacuum gauge circuit material layer 106 is patterned to obtain the micro vacuum gauge 300 and a first lead-out part 107 electrically connected to the micro vacuum gauge 300.

[0167] In some embodiments, the micro vacuum gauge 300 comprises a MEMS Pirani vacuum gauge, which utilizes the Pirani effect and the principle of thermoelectric coupling to realize pressure monitoring of a vacuum environment. The working principle of the MEMS Pirani vacuum gauge is that a heating component, such as a heating wire or a thin film, is heated to a high temperature by using a bridge circuit, for example. When the density of gas molecules changes, the heat transfer from the metal wire to the gas is affected, and this heat loss depends on the gas type and pressure, so that the energy required to keep the metal wire at a certain temperature also changes accordingly. Therefore, the amount of energy depends on the vacuum pressure and can be converted into a pressure value. Compared with traditional vacuum pressure gauges, the MEMS Pirani vacuum gauge has the advantages of small size, low energy consumption, low working temperature, fast thermal response time, and wide measurement range.

[0168] As an example, the vacuum gauge circuit material layer 106 is patterned by using conventional photolithography and metal etching and supporting process to form a test circuit in a composite series structure. The metal etching process can use an ion beam etching (IBE) method, for example.

[0169] (4) As shown in FIG. 6, a second insulating layer 108 is formed to cover the micro vacuum gauge 300 and the first lead-out part 107.

[0170] Specifically, the main function of the second insulating layer 108 is to prevent the suspended thin film structure from being damaged due to excessive stress during the subsequent etching of the bulk silicon. The specific material and thickness of the second insulating layer 108 can be designed according to the required performance of the micro vacuum gauge test circuit.

[0171] As an example, the second insulating layer 108 can be a single-material thin film, a composite thin film composed of multiple materials, or a composite thin film formed by stacking multiple single-material thin films.

[0172] In an embodiment, the second insulating layer 108 is a single thin film composed of silicon nitride, and the thickness is 0.5 microns.

[0173] In an embodiment, the second insulating layer 108 is prepared by using a conventional plasma enhanced chemical vapor deposition (PECVD) method.

[0174] (5) As shown in FIG. 7, a first contact hole 109 is formed in the second insulating layer 108 to expose the first lead-out portion 107, the first lead-out portion 107 passing through a region where a first support arm to be formed later and extending to a region where a sealed micro vacuum cavity to be formed later.

[0175] As an example, the second insulating layer 108 is processed to form the first contact hole 109 by using conventional photolithography and etching and supporting processes, for example, a silicon nitride etching process can be performed by using a silicon nitride etching machine.

[0176] (6) As shown in FIG. 8, a first electrode material layer 110 is formed on the second insulating layer 108, the first electrode material layer 110 being filled into the first contact hole 109.

[0177] Specifically, the specific material and thickness of the first electrode material layer 110 can be designed according to the performance required by the micro vacuum gauge test circuit.

[0178] In some embodiments, the material of the first electrode material layer 110 can be selected from one or more than one of Pt, W, Au, Al, Cu, Ni, Ta, Ti and Cr.

[0179] In other embodiments, the material of the first electrode material layer 110 can also be selected from a semiconductor, for example, polysilicon. When the material of the first electrode material layer 110 is polysilicon, the polysilicon can be doped according to the requirement to adjust its conductivity.

[0180] In other embodiments, the material of the first electrode material layer 110 can also be selected from a metal compound.

[0181] In an embodiment, the first electrode material layer 110 is a single thin film composed of metal Al, and the thickness of the first electrode material layer 110 is 0.6 microns.

[0182] In an embodiment, the first electrode material layer 110 is prepared by using a conventional physical vapor deposition (PVD) method.

[0183] (7) As shown in FIG. 9, the first electrode material layer 110 is patterned to obtain a first wire-bonding pad 111 electrically connected with the first lead-out portion 107 and a second wire-bonding pad 112 for electrically connecting with a vacuum degree control unit (to be described in the subsequent part based on a second substrate), the first wire-bonding pad 111 and the second wire-bonding pad 112 being both disposed outside a region where a sealed micro vacuum cavity to be formed later.

[0184] As an example, the patterning of the first electrode material layer 110 can be performed using conventional photolithography and etching and supporting processes, for example, a metal Al etching process can be performed using a metal etching machine.

[0185] In some embodiments, the patterning of the first electrode material layer 110 to obtain the first wire-bonding pad 111 and the second wire-bonding pad 112 also obtains a first bonding part 113 for bonding with the second substrate 200.

[0186] (8) As shown in FIG. 10, a third insulating layer 114 covering the first wire-bonding pad 111 and the second wire-bonding pad 112 is formed on the second insulating layer 108.

[0187] Specifically, the third insulating layer 114 has two main functions: one is to prevent the first wire-bonding pad 111, the second wire-bonding pad 112 and the first bonding part 113 (if any) from chemically reacting with the etching solution during the subsequent etching of the bulk silicon; the other is to prevent the first wire-bonding pad 111, the second wire-bonding pad 112 and the first bonding part 113 (if any) from being oxidized during the subsequent processing. The specific material and thickness of the third insulating layer 114 can be designed according to the required performance of the micro vacuum gauge test circuit electrode.

[0188] As an example, the third insulating layer 114 can be a single-material thin film, a composite thin film composed of multiple materials, or a composite thin film formed by laminating multiple single-material thin films.

[0189] In an embodiment, the third insulating layer 114 is a single thin film composed of silicon nitride, and the thickness is 0.5 microns.

[0190] In an embodiment, the third insulating layer 114 is prepared using a conventional PECVD method.

[0191] (9) As shown in FIG. 11, the first etching window 115 and the second etching window 116 are formed through the third insulating layer 114, the second insulating layer 108 and the first insulating layer 105.

[0192] As an example, the third insulating layer 114, the second insulating layer 108 and the first insulating layer 105 can be processed to obtain the first etching window 115 and the second etching window 116 using conventional photolithography and etching and supporting processes, for example, a silicon nitride etching process can be performed using a silicon nitride etching machine.

[0193] (10) As shown in FIG. 12, the first substrate 100 is etched via the first etching window 115 and the second etching window 116 to obtain the first cavity 103 and the second cavity 104, wherein a portion of the first insulating layer 105 is suspended above the first cavity 103 as a first support layer 105a, the first support layer 105a includes a first support body and at least one first support arm, one end of the first support arm is connected to the first support body, and the other end is connected to a rigid portion of the first substrate 100, and the micro vacuum gauge 300 is arranged on the side of the first support body away from the first cavity 103.

[0194] As an example, the first substrate 100 is etched by using a gas or plasma that has etching effect on silicon, at this time, the gas or plasma reaches the surface of the first substrate 100 through the first etching window 115 and the second etching window 116 to achieve etching. The etching gas may, for example, include XeF2, SF6, etc., and the etching plasma may, for example, include SF6 plasma, etc.

[0195] As an example, the first substrate 100 can also be etched by using a liquid that has etching effect on silicon. At this time, the etching liquid also reaches the surface of the first substrate 100 through the first etching window 115 and the second etching window 116 to achieve etching. In some embodiments, the etching liquid may, for example, include KOH, TMAH, etc.

[0196] Specifically, the first etching window 115 is not only used to provide an etchant passing window, but also used to define the shape of the first support body and the first support arm.

[0197] As an example, the first support body is in a circular shape, a polygonal shape or other suitable shape, the first support arm is in a straight line type, a broken line type or other suitable shape, and the number of the first support arm can be adjusted as needed.

[0198] Specifically, the first cavity 103 obtained after etching makes the main body structure of the micro vacuum gauge 300 in a suspended state, and only the cantilever beam (the first support arm) is connected to the first substrate 100.

[0199] As an example, please refer to Figure 29, which shows a plan view of the first support layer 105a, the micro vacuum gauge 300, the first lead-out portion 107 and surrounding structures in one embodiment. The first support body 1051a is rectangular, and the first support arm 1052a is zigzag-shaped, such as "L". There are four first support arms 1052a arranged in a swastika-like shape. The micro vacuum gauge 300 is located on the surface of the first support body 1051a. There are two first lead-out portions 107, one of which is connected to the positive terminal of the micro vacuum gauge 300, and the other is connected to the negative terminal of the micro vacuum gauge 300. The first lead-out portion 107 includes a lead wire 1071 and a lead-out disk 1072. The first support arm 1052a serves as a channel for laying the lead wire 1071 and provides a certain support strength for the first support body 1051a supporting the micro vacuum gauge 300 to prevent collapse.

[0200] As an example, please refer to Figure 30, which shows a plan view of the first support layer 105a, the micro vacuum gauge 300, the first lead-out portion 107 and the surrounding structure in another embodiment, wherein the first support body portion 1051a is rectangular, the first support arm 1052a is linear, and there are 4 first support arms 1052a distributed at the four apex corners of the first support body portion 1051a.

[0201] As an example, when the first support arm 1052a is a polygonal shape, it is preferable to use rounded corners at its corners, which helps to improve stress concentration.

[0202] (11) As shown in FIG13, the third insulating layer 114 is removed to expose the first wire bonding pad 111, the second wire bonding pad 112 and the first bonding portion 113 (if any).

[0203] As an example, the third insulating layer 114 can be removed using conventional etching and associated processes, such as silicon nitride etching using a silicon nitride etching machine.

[0204] The processing of the second substrate 200 will now be described. As an example, please refer to Figures 14 to 25, which show, in one embodiment, the process of forming a vacuum control unit 400 on a first main surface 201 of the second substrate 200, and forming mutually spaced third cavities 203 and fourth cavities 204 on the first main surface 201 of the second substrate 200, with the vacuum control unit 400 suspended above the fourth cavity 204:

[0205] (1) As shown in Fig. 14, a fourth insulating layer 205 is formed on the first main surface 201 of the second substrate 200.

[0206] Specifically, the fourth insulating layer 205 has three main functions: one is to electrically insulate the material of the vacuum degree control unit 400 from the material of the second substrate 200; the second is to support the thin film heater in the vacuum degree control unit 400; and the third is to thermally insulate the thin film heater from the second substrate 200, so that the heat generated by the thin film heater after being powered on can effectively flow to the direction of the getter film. The specific material and thickness of the fourth insulating layer 205 can be designed according to the required performance of the vacuum degree control unit.

[0207] As an example, the fourth insulating layer 205 can be a single material film, a composite film composed of multiple materials, or a composite film formed by stacking multiple single material films.

[0208] In an embodiment, the fourth insulating layer 205 is a single film composed of silicon nitride, and the thickness is 0.5 microns.

[0209] In an embodiment, the second substrate 200 is a silicon substrate, and the fourth insulating layer 205 is formed on the surface of the second substrate 200 using conventional LPCVD and corresponding supporting processes, wherein the first main surface 201 and the second main surface 202 of the second substrate 200 are both deposited with an insulating layer.

[0210] (2) As shown in Fig. 15, a thin film heater material layer 206 is formed on the fourth insulating layer 205.

[0211] As an example, the thin film heater material layer 206 is a 0.2 micron thick metal Ti layer formed using conventional magnetron sputtering and supporting processes.

[0212] (3) As shown in Fig. 16, the thin film heater material layer 206 is patterned to obtain a thin film heater 207 and a second lead-out portion 208 electrically connected to the thin film heater 207, and the second lead-out portion 208 extends to an area outside the subsequent to be formed sealed micro vacuum cavity through the subsequent to be formed second support arm area.

[0213] As an example, the thin film heater material layer 206 is patterned to obtain the thin film heater 207 using conventional photolithography and metal etching and supporting processes. The metal etching process can be performed using the IBE method.

[0214] (3) As shown in Fig. 17, a fifth insulating layer 209 is formed covering the thin film heater 207 and the second lead-out portion 208.

[0215] Specifically, the fifth insulating layer 209 has two main functions: one is to achieve electrical insulation between the thin-film heater 207 and the getter film formed subsequently; the other is to effectively conduct the heat generated by the thin-film heater 207 to the getter film, so that the temperature of the getter film reaches its activation temperature. The specific material and thickness of the fifth insulating layer 209 can be designed according to the required performance of the thin-film heater 207.

[0216] For example, the fifth insulating layer 209 can be a single-material thin film, a composite thin film composed of multiple materials, or a composite thin film formed by stacking multiple single-material thin films.

[0217] In an embodiment, the fifth insulating layer 209 is a single thin film composed of silicon nitride, and the thickness is 0.5 microns.

[0218] In an embodiment, the fifth insulating layer 209 is prepared by using a conventional PECVD method.

[0219] (4) As shown in FIG. 18, a second contact hole 210 exposing the second lead-out portion 208 is formed in the fifth insulating layer 209.

[0220] For example, the fifth insulating layer 209 is processed to form the second contact hole 210 by using conventional photolithography and etching and supporting processes, such as a silicon nitride etching process which can be performed by using a silicon nitride etching machine.

[0221] (5) As shown in FIG. 19, a second electrode material layer 211 is formed on the fifth insulating layer 209, and the second electrode material layer 211 fills into the second contact hole 210.

[0222] Specifically, the specific material and thickness of the second electrode material layer 211 can be designed according to the required performance of the vacuum degree control unit.

[0223] In some embodiments, the material of the second electrode material layer 211 can be selected from one or more than two metals including Pt, W, Au, Al, Cu, Ni, Ta, Ti, and Cr.

[0224] In other embodiments, the material of the second electrode material layer 211 can also be selected from a semiconductor, such as polysilicon. When the material of the second electrode material layer 211 is polysilicon, the polysilicon can be doped as needed to adjust its conductivity.

[0225] In other embodiments, the material of the second electrode material layer 211 can also be selected from a metal compound.

[0226] In one embodiment, the second electrode material layer 211 is a single thin film composed of metal Ge, and has a thickness of 0.4 microns.

[0227] In one embodiment, the second electrode material layer 211 is prepared by using a conventional PVD method.

[0228] (6) As shown in FIG. 20, the second electrode material layer 211 is patterned to obtain a connection pad 212 electrically connected with the second lead-out portion 208.

[0229] As an example, the patterning of the second electrode material layer 211 can be performed by using a conventional photolithography and etching method and a supporting process. For example, the metal Ge etching process can be performed by using a metal etching machine.

[0230] In some embodiments, when the second electrode material layer 211 is patterned to obtain the connection pad 212, a second bonding portion 213 for bonding with the first substrate 100 is also obtained.

[0231] For example, in some embodiments, one of the first bonding portion 113 made on the first substrate 100 and the second bonding portion 213 made on the second substrate 200 comprises an Al layer, and the other comprises a Ge layer. After the first bonding portion 113 and the second bonding portion 213 are bonded with each other, an Al-Ge eutectic bonding layer is formed.

[0232] (7) As shown in FIG. 21, a sixth insulating layer 214 covering the connection pad 212 is formed on the fifth insulating layer 209.

[0233] Specifically, the sixth insulating layer 214 has two main functions: one is to prevent the connection pad 212 and the second bonding portion 213 (if any) from chemically reacting with a corrosion solution in a subsequent etching silicon process; and the other is to prevent the connection pad 212 and the second bonding portion 213 (if any) from being oxidized in a subsequent processing process. The specific material and thickness of the sixth insulating layer 214 can be designed according to the required performance of the vacuum degree control unit electrode.

[0234] As an example, the sixth insulating layer 214 can be a thin film composed of a single material, a composite thin film composed of multiple materials, or a composite thin film formed by stacking multiple thin films composed of single materials.

[0235] In one embodiment, the sixth insulating layer 214 is a single thin film composed of silicon nitride, and has a thickness of 0.5 microns.

[0236] In one embodiment, the sixth insulating layer 214 is prepared by using a conventional PECVD method.

[0237] (8) As shown in FIG. 22, third and fourth etching windows 215 and 216 are formed through the sixth insulating layer 214, the fifth insulating layer 209, and the fourth insulating layer 205.

[0238] As an example, the third and fourth etching windows 215 and 216 can be formed by using conventional photolithography and etching and supporting processes, for example, a silicon nitride etching process can be performed by using a silicon nitride etching machine.

[0239] In some embodiments, an alignment pin 217 for fixing a metal mask for depositing a getter film (to be described in detail later) is also formed, the alignment pin 217 passes through the sixth insulating layer 214, the fifth insulating layer 209, and the fourth insulating layer 205, and extends into the second substrate 200.

[0240] As an example, the alignment pin 217 can be formed by using conventional photolithography and etching and supporting processes, for example, a silicon surface processing etching process can be performed by using a deep silicon etching machine.

[0241] As an example, the alignment pin 217 is formed first, and then the third and fourth etching windows 215 and 216 are formed.

[0242] (9) As shown in FIG. 23, the second substrate 200 is etched through the third and fourth etching windows 215 and 216 to form the third and fourth cavities 203 and 204, wherein a portion of the fourth insulating layer 205 is suspended above the fourth cavity 204 as a second support layer 205a, the second support layer 205a includes a second support main body portion and at least one second support arm, one end of the second support arm is connected to the second support main body portion, and the other end is connected to a rigid portion of the second substrate 200, and the thin-film heater material layer 206 is arranged on a side of the second support main body portion away from the fourth cavity 204.

[0243] As an example, the second substrate 200 is etched by using a gas or plasma that has etching effect on silicon, at this time, the gas or plasma reaches the surface of the second substrate 200 through the third and fourth etching windows 215 and 216 to achieve etching. The etching gas can include XeF2, SF6, etc., and the etching plasma can include SF6 plasma, etc.

[0244] As an example, the second substrate 200 can also be etched using a liquid that etches silicon. In this case, the etching liquid also reaches the surface of the second substrate 200 through the third etching window 215 and the fourth etching window 216 to achieve etching. In some embodiments, the etching liquid can include KOH, TMAH, or the like, for example.

[0245] Specifically, the fourth etching window 216 is used not only to provide a passage for the etching agent, but also to define the shape of the second support body portion and the second support arm.

[0246] As an example, the second support body portion can be circular, polygonal, or other suitable shape, the second support arm can be linear, zigzag, or other suitable shape, and the number of second support arms can be adjusted as needed. When the second support arm is zigzag, the corners thereof are preferably rounded to help improve stress concentration.

[0247] Specifically, the fourth cavity 204 obtained after etching causes the main body structure of the vacuum degree control unit to be in a suspended state, and only the cantilever beam (the second support arm) is connected to the second substrate 200.

[0248] (10) As shown in FIG. 24, the sixth insulating layer 214 is removed.

[0249] As an example, the sixth insulating layer 214 can be removed using conventional etching and supporting processes. For example, a silicon nitride etching process can be performed using a silicon nitride etching machine.

[0250] (11) As shown in FIGS. 25 and 26, a getter film 218 is formed above the thin-film heater 207, and the getter film 218 and the thin-film heater 207 are separated from each other by the fifth insulating layer 209.

[0251] Specifically, the area of the getter film 218 is smaller than the area of the fifth insulating layer 209, the getter film 218 and the thin-film heater 207 constitute part of the vacuum degree control unit 400, and the getter film 218 is located on the side of the thin-film heater 207 away from the second support layer 205a and is separated from the thin-film heater 207 by the fifth insulating layer 209.

[0252] As an example, the getter film 218 includes at least one of a Ti-based non-evaporable getter material and a Zr-based non-evaporable getter material, but is not limited thereto.

[0253] In an embodiment, the thickness of the getter film 218 is about 0.5 micrometers.

[0254] In some embodiments, forming the getter film 218 above the thin film heater 207 comprises the following steps:

[0255] (11-1) As shown in FIG. 25, a metal mask 219 is overlaid on the second substrate 200, the metal mask 219 is provided with a deposition window 220 above the fourth cavity 204;

[0256] (11-2) As shown in FIG. 25, the getter film 218 is deposited on the fifth insulating layer 209 based on the deposition window 220, and the deposition method can be, for example, a magnetron sputtering method;

[0257] (11-3) As shown in FIG. 26, the metal mask 219 is removed.

[0258] Specifically, the use of a metal mask has the advantage that etching processing of the getter film is not required, avoiding possible contamination of the getter film during etching processing. Another advantage of using a metal mask is that the getter film formation process is simple, and the metal mask can be reused, reducing manufacturing costs.

[0259] At this point, the processing of the first substrate 100 and the second substrate 200 is completed.

[0260] Next, referring to FIG. 27, the S4 is performed: the first main surface 201 of the second substrate 200 and the first main surface 101 of the first substrate 100 are arranged to face each other and bonded to form a sealed micro vacuum cavity 500, the sealed micro vacuum cavity 500 comprises a first vacuum cavity 501, a gas molecule flow passage 502 and a second vacuum cavity 503 which are sequentially connected, the first vacuum cavity 501 is composed of the first cavity 103 and the third cavity 203, the second vacuum cavity 503 is composed of the second cavity 104 and the fourth cavity 204, the first substrate 100 and the second substrate 200 are spaced apart by a certain distance in the area between the first vacuum cavity 501 and the second vacuum cavity 503 to define the gas molecule flow passage 502, the micro vacuum gauge 300 is used to monitor the internal vacuum degree of the sealed micro vacuum cavity 500, and the vacuum degree control unit 400 is used to adjust the internal vacuum degree of the sealed micro vacuum cavity 500.

[0261] Specifically, in the bonding area, the film layer on the first main surface 101 of the first substrate 100 and the film layer on the first main surface 201 of the second substrate 200 are in airtight contact, enclosing the sealed micro vacuum cavity 500 and making it airtight from the surrounding environment.

[0262] In some embodiments, the first substrate 100 and the second substrate 200 are bonded to each other through the first bonding portion 113 and the second bonding portion 213.

[0263] Specifically, the area, depth and other structural parameters of the first recessed cavity 103 and the third recessed cavity 203 constituting the first vacuum cavity 501 can be determined according to the structure of the micro vacuum gauge 300 accommodated therein. The main function of the first vacuum cavity 501 is to provide accommodation space for the micro vacuum gauge 300, so that the circuit resistance of the micro vacuum gauge 300 becomes a suspended thin film, to provide space for the movement of gas molecules and to ensure real-time monitoring of the vacuum degree inside the micro vacuum cavity. The size, area and other structural parameters of the micro vacuum gauge 300 can be determined according to the range of the vacuum degree to be measured.

[0264] Specifically, the area, depth and other structural parameters of the second recessed cavity 104 and the fourth recessed cavity 204 constituting the second vacuum cavity 503 can be determined according to the structure of the vacuum degree control unit 400 accommodated therein. The main function of the second vacuum cavity 503 is to provide a certain accommodation space for the vacuum degree control unit 400, so that the thin film heater of the vacuum degree control unit 400 becomes a suspended thin film, to provide conditions for the operation of the vacuum degree control unit 400 and to control the vacuum degree inside the micro vacuum cavity. The size, area and other structural parameters of the vacuum degree control unit 400 can be determined according to the range of the vacuum degree inside the micro vacuum cavity to be controlled.

[0265] Specifically, the first vacuum cavity 501 and the second vacuum cavity 503 are in communication with each other through the gas molecule flow passage 502, which is arranged on the surface of the substrate and is formed by the gap between the film layers of the two substrate surfaces, solving the problem of consistency of the vacuum degree inside the micro vacuum cavity, removing many limitations, making the structure more compact and the cost more low, and being suitable for more microelectronic devices.

[0266] In some embodiments, the gas molecule flow passage 502 has a circular or polygonal shape in the orthographic projection shape on the plane of the first substrate. The height of the gas molecule flow passage ranges from 1.5 microns to 50 microns.

[0267] In some embodiments, the first main surface 101 of the first substrate 100 and the first main surface 201 of the second substrate 200 in the area where the gas molecule flow passage 502 is located can not be etched. In other embodiments, at least one of the first main surface 101 of the first substrate 100 and the first main surface 201 of the second substrate 200 in the area where the gas molecule flow passage 502 is located is etched to a certain depth, so that the final gas molecule flow passage 502 has a greater height.

[0268] As an example, referring to FIG. 28, in order to ensure the successful completion of the subsequent packaging process, the second substrate 200 after the completion of the bonding is subjected to etching treatment to expose the first wire bonding pad 111 and the second wire bonding pad 112 on the first substrate 100 for subsequent wire bonding packaging. This processing process can be performed using conventional etching and supporting processes. One specific example of the etching process can use a deep reactive ion etching method.

[0269] As an example, the manufacturing method of the MEMS packaging structure of the present application, on the basis of forming the micro vacuum gauge 300 and the vacuum degree control unit 400, further includes the step of forming other microelectronic devices, for example, in some embodiments, one or more of a MEMS accelerometer, a MEMS pressure sensor, a MEMS gyroscope or other types of MEMS sensors can be formed, which can be based on the first substrate 100 or the second substrate 200, and after packaging, located in the sealed micro vacuum cavity 500, for example, in the first vacuum cavity 501 or the second vacuum cavity 503.

[0270] So far, a MEMS packaging structure has been manufactured. The manufacturing method of the MEMS packaging structure of the present application integrates the micro vacuum gauge 300 and the vacuum degree control unit 400 inside the sealed micro vacuum cavity 500, which has a simple process and high compatibility. It can measure the vacuum degree inside the sealed micro vacuum cavity 500 using the micro vacuum gauge 300 while starting the work of the vacuum degree control unit 400, thereby completing the control of the vacuum degree inside the sealed micro vacuum cavity 500, providing strong support for the design and manufacture of subsequent MEMS inertial devices.

[0271] Specifically, the internal air pressure of the four cavities, i.e., the first cavity 103, the second cavity 104, the third cavity 203 and the fourth cavity 204, is positively correlated with the internal air pressure of the sealed micro vacuum cavity 500. The air tightness of the sealed micro vacuum cavity 500 can be reflected by monitoring the reading of the micro vacuum gauge 300. Specifically, when the internal air pressure of the sealed micro vacuum cavity 500 is different from the external environmental air pressure where the chip is located, the reading of the micro vacuum gauge 300 will change, realizing real-time monitoring of the vacuum degree in the micro vacuum gauge 300. When the reading of the micro vacuum gauge 300 changes, it indicates that the internal vacuum degree of the sealed micro vacuum cavity 500 starts to change. At the same time, it can be determined according to the vacuum degree measurement result whether the vacuum degree control unit 400 should be activated. If it is determined that the vacuum degree control unit 400 should be activated, the thin film heater 207 of the vacuum degree control unit 400 is powered on to make its temperature rise, and the getter thin film 218 starts to work to adsorb the gas molecules in the sealed micro vacuum cavity 500, so that the air pressure in the sealed micro vacuum cavity 500 returns to the required vacuum degree, thereby providing a good working environment for the microelectronic devices in the sealed micro vacuum cavity 500, ensuring the working reliability of the microelectronic devices, making the microelectronic devices accurately obtain the real value of the measured physical quantity, and thereby prolonging the service life of the MEMS device.

[0272] In summary, the manufacturing method of the MEMS packaging structure of the present application forms a micro vacuum gauge on the first main surface of the first substrate, forms a vacuum degree control unit on the first main surface of the second substrate, and forms a first cavity and a second cavity spaced from each other on the first main surface of the first substrate, and forms a third cavity and a fourth cavity spaced from each other on the first main surface of the second substrate. The micro vacuum gauge is suspended above the first cavity, and the vacuum degree control unit is suspended above the fourth cavity. Then, the first main surface of the second substrate and the first main surface of the first substrate are arranged to face each other and bonded to form a sealed micro vacuum cavity. The sealed micro vacuum cavity includes a first vacuum cavity, a gas molecule flow passage and a second vacuum cavity connected in sequence. The micro vacuum gauge is located in the first vacuum cavity for monitoring the internal vacuum degree of the sealed micro vacuum cavity, and the vacuum degree control unit is located in the second vacuum cavity for adjusting the internal vacuum degree of the sealed micro vacuum cavity. The manufacturing method of the MEMS packaging structure of the present application integrates the micro vacuum gauge and the vacuum degree control unit in the same micro vacuum cavity, which can realize real-time monitoring and real-time control of the internal vacuum degree of the micro vacuum cavity where the microelectronic devices are located at the same time. The manufacturing method has the advantages of simple process and high compatibility. Therefore, the present application effectively overcomes the shortcomings of the prior art and has high industrial utilization value.

[0273] The above embodiments are only illustrative of the principles of the present application and its efficacy, and are not intended to limit the present application. Any modification or change made by any person skilled in the art without departing from the spirit and scope of the present application shall be covered by the claims of the present application.

Claims

1. A method of manufacturing a MEMS package structure, characterized by, The method comprises the following steps: providing a first substrate and a second substrate, the first substrate having a first main surface and a second main surface arranged oppositely, and the second substrate having a first main surface and a second main surface arranged oppositely; forming a micro vacuum gauge on the first main surface of the first substrate and a vacuum degree control unit on the first main surface of the second substrate; forming a first cavity and a second cavity spaced apart from each other on the first main surface of the first substrate and suspending the micro vacuum gauge above the first cavity, and forming a third cavity and a fourth cavity spaced apart from each other on the first main surface of the second substrate and suspending the vacuum degree control unit above the fourth cavity; arranging the first main surface of the second substrate and the first main surface of the first substrate to face each other and bonding to form a sealed micro vacuum cavity, the sealed micro vacuum cavity comprising a first vacuum cavity, a gas molecule flow channel and a second vacuum cavity connected in sequence, the first vacuum cavity being composed of the first cavity and the third cavity, the second vacuum cavity being composed of the second cavity and the fourth cavity, the first substrate and the second substrate being spaced apart by a distance in the region between the first vacuum cavity and the second vacuum cavity to define the gas molecule flow channel, the micro vacuum gauge being used for monitoring the internal vacuum degree of the sealed micro vacuum cavity, and the vacuum degree control unit being used for adjusting the internal vacuum degree of the sealed micro vacuum cavity.

2. The method of manufacturing a MEMS package structure according to claim 1, wherein The method comprises the following steps: forming a first insulating layer on the first main surface of the first substrate; forming the micro vacuum gauge on the first insulating layer; forming a first etching window and a second etching window penetrating through the first insulating layer; etching the first substrate through the first etching window and the second etching window to obtain the first cavity and the second cavity, wherein a part of the first insulating layer is suspended above the first cavity as a first support layer, the first support layer comprising a first support body part and at least one first support arm, one end of the first support arm being connected to the first support body part, and the other end being connected to a rigid part of the first substrate, and the micro vacuum gauge being arranged on the side of the first support body part away from the first cavity.

3. The method of manufacturing a MEMS package structure according to claim 2, wherein The method comprises the following steps: forming a vacuum gauge circuit material layer on the first insulating layer; patterning the vacuum gauge circuit material layer to obtain the micro vacuum gauge and a first lead-out part electrically connected to the micro vacuum gauge, the first lead-out part extending through the region where the first support arm is located and extending to the region outside the sealed micro vacuum cavity; forming a second insulating layer covering the micro vacuum gauge and the first lead-out part; forming a first contact hole exposing the first lead-out part in the second insulating layer; forming a first electrode material layer on the second insulating layer, the first electrode material layer being filled into the first contact hole; patterning the first electrode material layer to obtain a first wire-bonding pad electrically connected to the first lead-out part and a second wire-bonding pad for electrically connecting to the vacuum degree control unit, the first wire-bonding pad and the second wire-bonding pad being arranged outside the region of the sealed micro vacuum cavity. forming a third insulating layer covering the first wire-bonding pad and the second wire-bonding pad on the second insulating layer; forming the first etching window and the second etching window through the third insulating layer, the second insulating layer and the first insulating layer; etching the first substrate through the first etching window and the second etching window to obtain the first cavity and the second cavity; removing the third insulating layer.

4. The method of claim 3, wherein: In the process of patterning the first electrode material layer to obtain the first wire-bonding pad electrically connected with the first lead-out part and the second wire-bonding pad for electrically connecting with the vacuum degree control unit, a first bonding part for bonding with the second substrate is also obtained.

5. The method of claim 1, wherein comprising the following steps: forming a fourth insulating layer on a first main surface of the second substrate; forming the vacuum degree control unit on the fourth insulating layer; forming a third etching window and a fourth etching window through the fourth insulating layer; etching the second substrate through the third etching window and the fourth etching window to obtain the third cavity and the fourth cavity, wherein a part of the fourth insulating layer is suspended above the fourth cavity as a second support layer, the second support layer comprising a second support main part and at least one second support arm, one end of the second support arm being connected with the second support main part and the other end being connected with a rigid part of the second substrate, the vacuum degree control unit being arranged on a side of the second support main part facing away from the fourth cavity.

6. The method of manufacturing a MEMS package structure according to claim 5, wherein comprising the following steps: forming a thin-film heater material layer on the fourth insulating layer; patterning the thin-film heater material layer to obtain a thin-film heater and a second lead-out part electrically connected with the thin-film heater, the second lead-out part passing through the area where the second support arm is located and extending to an area outside the sealed micro-vacuum cavity; forming a fifth insulating layer covering the thin-film heater and the second lead-out part; forming a second contact hole exposing the second lead-out part in the fifth insulating layer; forming a second electrode material layer on the fifth insulating layer, the second electrode material layer filling into the second contact hole; patterning the second electrode material layer to obtain a connecting pad electrically connected with the second lead-out part; forming a sixth insulating layer covering the connecting pad on the fifth insulating layer; forming the third etching window and the fourth etching window through the sixth insulating layer, the fifth insulating layer and the fourth insulating layer; etching the second substrate through the third etching window and the fourth etching window to obtain the third cavity and the fourth cavity; removing the sixth insulating layer; forming a getter thin-film above the thin-film heater, the getter thin-film and the thin-film heater being isolated from each other by the fifth insulating layer. In the process of patterning the second electrode material layer to obtain the connecting pad electrically connected with the second lead-out part, a second bonding part for bonding with the first substrate is also obtained.

7. The method of claim 6, wherein: forming a getter thin-film above the thin-film heater comprises the following steps:

8. The method of claim 6, wherein covering a metal mask on the second substrate, the metal mask being provided with a deposition window above the fourth cavity; ​ Depositing the getter film on the fifth insulating layer based on the deposition window; Dismounting the metal mask.

9. The method of claim 1, wherein: The micro vacuum gauge comprises a MEMS Pirani vacuum gauge.

10. The method of claim 1, wherein: The gas molecule flow channel has a shape of a circle or a polygon in a shape of a normal projection of the gas molecule flow channel on a plane in which the first substrate is located, and a height of the gas molecule flow channel ranges from 1.5 microns to 50 microns.

11. The method of claim 1, wherein: Further comprising a step of forming a MEMS sensor, the MEMS sensor being arranged in the first vacuum cavity or the second vacuum cavity, the MEMS sensor comprising one or more of a MEMS accelerometer, a MEMS pressure sensor, and a MEMS gyroscope.

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