Method of fabricating microelectronic device package structures

Abstract

The application provides a preparation method of a microelectronic device packaging structure, which can realize real-time in-situ monitoring of the vacuum degree inside a micro-hermetic vacuum cavity in the microelectronic device packaging structure by integrating a micro vacuum gauge in the micro-hermetic vacuum cavity, and has simple process and high compatibility. Further, by integrating the micro vacuum gauge, a vacuum degree regulating part and a temperature monitoring part in the micro-hermetic vacuum cavity, real-time in-situ monitoring of the vacuum degree in the micro-hermetic vacuum cavity can be realized based on the micro vacuum gauge and the temperature monitoring part, and when the vacuum degree changes, the vacuum degree regulating part is activated to keep the vacuum degree in a required interval of the microelectronic device, thereby ensuring the reliability of the performance of the microelectronic device, and the microelectronic device can accurately obtain the real value of the measured physical quantity, thereby prolonging the service life of the microelectronic device.

Description

Technical Field

[0001] This invention relates to the field of integrated design and manufacturing of microelectronic devices, and in particular to a method for preparing a microelectronic device packaging structure. Background Technology

[0002] For many semiconductor sensors, especially microelectromechanical systems (MEMS) sensors, their performance is affected by the vacuum level in which they operate, typically requiring a high vacuum environment (~10⁻² Pa) to achieve the desired sensitivity and quality factor. These MEMS devices include inertial sensors such as MEMS gyroscopes and MEMS accelerometers, as well as other types of sensors such as pressure sensors, MEMS micromirrors, and microbolometers. For gyroscopes, increasing the vacuum level within their sealed cavity reduces air damping during operation by decreasing the number of gas molecules inside, thus achieving a high quality factor and low noise. For accelerometers, changes in vacuum level are a key factor affecting their dynamic response performance; a high vacuum level keeps the air damping of the accelerometer's diaphragm at a low level, thereby improving sensitivity. For pressure sensors, a high vacuum environment ensures high sensitivity and a high quality factor in device measurements. For MEMS micromirrors, collisions of gas molecules on the micromirror surface significantly affect the device's quality factor, while a high vacuum environment can reduce energy loss by the micromirror, thus improving the quality factor. For microbolometers, which absorb infrared energy to cause temperature changes, a vacuum environment results in a longer average molecular free path for particles, which helps suppress gas heat conduction, allowing heat to be primarily conducted through thermal radiation, thereby improving device sensitivity.

[0003] The Q-factor of a MEMS sensor depends not only on the sensor design but also, to a large extent, on the pressure level of the sealed MEMS. To ensure the sensor operates at an ideal state, it is necessary to monitor the vacuum level within it. However, in practical applications, because the packaged sensor is in a sealed state, it is difficult to monitor its internal vacuum level without damaging the sensor. Consequently, the decrease in internal vacuum is only detected after the sensor malfunctions, by which time it is often too late.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for preparing a microelectronic device packaging structure, which solves the problem of real-time in-situ monitoring of the vacuum level inside the vacuum cavity in the prior art microelectronic device packaging structure.

[0006] To achieve the above and other related objectives, the present invention provides a method for fabricating a microelectronic device packaging structure, characterized in that the fabrication method includes:

[0007] S1 provides a first structural unit and a second structural unit; a miniature vacuum gauge is integrated in the first structural unit or the second structural unit;

[0008] S2, the first structural unit and the second structural unit are bonded together to form a miniature sealed vacuum cavity. The miniature vacuum gauge is located inside the miniature sealed vacuum cavity and is used to monitor the vacuum level inside the miniature sealed vacuum cavity.

[0009] Optionally, the micro vacuum gauge includes one or more combinations of MEMS Pirani vacuum gauge structure and diode-type vacuum gauge structure.

[0010] Optionally, the material of the micro vacuum gauge includes one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, tantalum, chromium, titanium nitride, polycrystalline silicon, monocrystalline silicon, carbon nanotubes, and graphene.

[0011] Optionally, the fabrication method further includes the step of forming a MEMS sensor, wherein the MEMS sensor is disposed in the micro-sealed vacuum cavity, and the MEMS sensor includes one or more combinations of MEMS gyroscope, MEMS accelerometer, MEMS pressure sensor, MEMS resonator and MEMS micromirror.

[0012] Optionally, the miniature sealed vacuum cavity formed by the bonding connection of the first structural unit and the second structural unit further integrates a vacuum degree control part and / or a temperature monitoring part. The vacuum degree control part is used to control the vacuum degree in the miniature sealed vacuum cavity, and the temperature monitoring part is used to monitor the temperature in the miniature sealed vacuum cavity and perform temperature compensation for the miniature vacuum gauge.

[0013] Furthermore, the temperature monitoring section includes one or more combinations of diodes, thermistors, thermocouples, thermopile, and resonators.

[0014] Further, in step S1, the first structural unit integrates the micro vacuum gauge and the temperature monitoring part, and the second structural unit integrates the vacuum degree control part; wherein,

[0015] The preparation method of step S1 includes:

[0016] S10 provides a first structural unit and a second structural unit; wherein...

[0017] The first structural unit includes a first substrate, the first substrate having a first surface and a second surface opposite to each other, and the temperature monitoring part, the first cavity and the micro vacuum gauge suspended on the top of the first cavity are formed on the first surface of the first substrate;

[0018] The second structural unit includes a second substrate, the second substrate having a first surface and a second surface opposite to each other, and a second cavity, a third cavity and the vacuum control portion suspended on the top of the second cavity are formed on the first surface of the second substrate;

[0019] The preparation method of step S2 includes:

[0020] S20, the first bonding portion on the first surface of the first substrate of the first structural unit and the second bonding portion on the first surface of the second substrate of the second structural unit are bonded together, wherein the second cavity of the second structural unit corresponds to the position of the temperature monitoring portion of the first structural unit, and the third cavity of the second structural unit corresponds to the position of the first cavity of the first structural unit, so as to form a micro-sealed vacuum cavity. The micro-sealed vacuum cavity includes a first vacuum cavity, a second vacuum cavity, and a gas molecule channel connecting the first vacuum cavity and the second vacuum cavity. The first vacuum cavity is composed of the second cavity, and the second vacuum cavity is composed of the first cavity and the third cavity.

[0021] Furthermore, the orthographic projection shape of the gas molecule channel onto the plane of the first substrate is circular, rectangular, or polygonal, and the height of the gas molecule channel is 0.1µm to 100µm.

[0022] Further, the first substrate includes one or more combinations of silicon substrate, SiC substrate, quartz substrate, sapphire substrate and glass substrate; the second substrate includes one or more combinations of silicon substrate, SiC substrate, quartz substrate, sapphire substrate and glass substrate.

[0023] Furthermore, the method for preparing the first structural unit includes:

[0024] The first substrate is provided, and a first support layer is formed on a first surface of the first substrate;

[0025] The temperature monitoring section is formed by ion implantation into a predetermined area on the first surface of the first substrate.

[0026] The miniature vacuum gauge is formed on the first support layer;

[0027] A first etching window is formed through the first support layer to expose the first surface of the first substrate; the first substrate is etched through the first etching window to obtain the first cavity; and a portion of the first support layer is suspended on top of the first cavity as the first support structure of the micro vacuum gauge. The first support structure includes a first support body and a first support arm, one end of the first support arm is connected to the first support body, and the other end is connected to the rigid portion of the first substrate.

[0028] Furthermore, the method for forming the temperature monitoring portion by ion implantation into a predetermined region on the first surface of the first substrate includes:

[0029] A predetermined area on the first surface of the first substrate is subjected to N-type doping to a predetermined depth to form an N-type doped first portion. A predetermined area of ​​the N-type doped first portion is subjected to P-type doping to a predetermined depth to form a P-type doped first portion. A predetermined area of ​​the N-type doped first portion is subjected to N-type doping to a predetermined depth to form an N-type doped second portion. A predetermined area of ​​the P-type doped first portion is subjected to P-type doping to a predetermined depth to form a P-type doped second portion. The N-type doped second portion is disposed around and spaced apart from the P-type doped first portion. The doping concentration of the N-type doped second portion is greater than that of the N-type doped first portion, and the doping concentration of the P-type doped second portion is greater than that of the P-type doped first portion. The N-type doped first portion, the P-type doped first portion, the N-type doped second portion, and the P-type doped second portion constitute the temperature monitoring portion.

[0030] Furthermore, forming the micro vacuum timer on the first support layer also includes the steps of forming a first lead-out portion electrically connected to the micro vacuum timer and a second lead-out portion electrically connected to the temperature monitoring portion;

[0031] A first etching window is formed through the first support layer to expose a first surface of the first substrate; the first substrate is etched through the first etching window to obtain the first cavity; and a portion of the first support layer is suspended above the first cavity as a first support structure for the micro vacuum gauge, the first support structure including a first support body and a first support arm, one end of the first support arm being connected to the first support body and the other end being connected to a rigid portion of the first substrate. The method includes:

[0032] A first covering layer is formed to cover the first support layer and the micro vacuum gauge, and to expose the temperature monitoring part, the first lead-out part and the second lead-out part;

[0033] A first wire bonding pad electrically connected to the first lead-out portion, a second wire bonding pad electrically connected to the vacuum degree control portion after step S20, and a third wire bonding pad electrically connected to the second lead-out portion are formed; after the bonding connection in step S20, the first wire bonding pad, the second wire bonding pad, and the third wire bonding pad are all located outside the micro sealed vacuum cavity.

[0034] A second cover layer is formed covering the first cover layer, the first wire bonding pad, the second wire bonding pad, and the third wire bonding pad;

[0035] A first etching window is formed that penetrates the second cover layer, the first cover layer, and the first support layer to expose the first surface of the first substrate;

[0036] The first substrate is etched through the first etching window to obtain the first cavity; and a portion of the first support layer is suspended on top of the first cavity as the first support structure of the micro vacuum gauge. The first support structure includes a first support body and a first support arm. One end of the first support arm is connected to the first support body, and the other end is connected to the rigid portion of the first substrate.

[0037] Remove the second overlay.

[0038] Further, the method for forming the first wire bonding pad electrically connected to the first lead-out portion, the second wire bonding pad electrically connected to the vacuum degree control portion after step S20, and the third wire bonding pad electrically connected to the second lead-out portion includes:

[0039] A first electrode material layer is formed to cover the first cover layer, and the first electrode material layer fills the contact holes that expose the temperature monitoring portion, the first lead-out portion and the second lead-out portion;

[0040] The first electrode material layer is patterned to form the first wire bonding pad, the second wire bonding pad, and the third wire bonding pad, and the first bonding portion is formed simultaneously.

[0041] Furthermore, the method for preparing the second structural unit includes:

[0042] The second substrate is provided, and a second support layer is formed on a first surface of the second substrate;

[0043] The vacuum control portion is formed on the second support layer, and the vacuum control portion includes a micro heater and a getter film.

[0044] A second etching window is formed that penetrates the second support layer; the second substrate is etched through the second etching window to obtain the second cavity; and a portion of the second support layer is suspended above the second cavity as a second support structure for the micro heater. The second support structure includes a second support body and a second support arm, one end of the second support arm is connected to the second support body, and the other end is connected to the rigid portion of the second substrate.

[0045] Furthermore, the material of the micro heater includes one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, tantalum, chromium, titanium nitride, polycrystalline silicon, monocrystalline silicon, carbon nanotubes, and graphene.

[0046] Furthermore, the method for preparing the second structural unit includes:

[0047] The micro heater and a third lead-out portion electrically connected to the micro heater are formed on the second support layer;

[0048] A third covering layer is formed to cover the second support layer and the micro heater, and to expose the third lead-out portion;

[0049] A connection pad is formed that is electrically connected to the third lead-out portion. After bonding in step S20, the connection pad is located outside the micro-sealed vacuum cavity.

[0050] The third cavity is formed by extending from the surface of the third cover layer away from the second substrate to a predetermined depth in the second substrate;

[0051] A fourth cover layer is formed, covering the third cover layer, the connecting pads, and the third cavity;

[0052] A second etching window is formed that penetrates the fourth cover layer, the third cover layer, and the second support layer to expose the first surface of the second substrate;

[0053] The second substrate is etched through the second etching window to obtain the second cavity; and a portion of the second support layer is suspended above the second cavity as the second support structure of the micro heater. The second support structure includes a second support body and a second support arm. One end of the second support arm is connected to the second support body, and the other end is connected to the rigid portion of the second substrate.

[0054] Remove the fourth overlay layer;

[0055] The getter film is formed on the third cover layer, and the getter film is located above the side of the micro heater away from the second substrate; the getter film and the micro heater constitute the vacuum control part.

[0056] Furthermore, the method for forming the connection pad electrically connected to the third lead, and after bonding in step S20, having the connection pad located outside the micro-sealed vacuum cavity includes:

[0057] A second electrode material layer is formed to cover the third cover layer, and the second electrode material layer fills the contact hole that exposes the third lead-out portion;

[0058] The second electrode material layer is patterned to form the connection pads and simultaneously form the second bonding portion.

[0059] Furthermore, after the third cover layer extends from the surface away from the second substrate to a predetermined depth in the second substrate to form the third cavity, the method further includes forming a plurality of diced through holes penetrating the third cover layer, the second support layer, and the second substrate. After step S20, the diced through holes expose the first wire bonding pad, the second wire bonding pad, and the third wire bonding pad.

[0060] Further, the method of forming the getter film on the third covering layer includes:

[0061] A mask is provided and the mask is placed over the surface of the structure on which the third capping layer is formed, wherein a deposition window for the getter film is formed in the mask;

[0062] Based on the deposition window, the getter film is deposited on the third capping layer to form the getter film;

[0063] Remove the mask.

[0064] Furthermore, the material of the getter film includes one or more combinations of Ti-based non-evaporable getter materials, Zr-based non-evaporable getter materials, Hf-based non-evaporable getter materials, V-based non-evaporable getter materials, Nb-based non-evaporable getter materials, Ta-based non-evaporable getter materials, Pd-based non-evaporable getter materials, Cr / Ni alloy-based non-evaporable getter materials, and rare earth-based non-evaporable getter materials.

[0065] As described above, the fabrication method of the microelectronic device packaging structure of the present invention has the following beneficial effects: By integrating a micro vacuum gauge into the micro-sealed vacuum cavity of the microelectronic device packaging structure, real-time in-situ monitoring of the vacuum level inside the micro-sealed vacuum cavity in the microelectronic device packaging structure can be achieved. This manufacturing method has the advantages of simple process and high compatibility. Furthermore, by integrating the micro vacuum gauge, vacuum level control part, and temperature monitoring part together inside the micro-sealed vacuum cavity, real-time in-situ accurate monitoring of the vacuum level inside the micro-sealed vacuum cavity can be performed based on the micro vacuum gauge and temperature monitoring part. When the vacuum level inside the micro-sealed vacuum cavity changes, the vacuum level control part can be heated and activated to keep the vacuum level inside the micro-sealed vacuum cavity within the required range of the relevant microelectronic device, thereby ensuring the reliability of the microelectronic device performance and enabling the relevant microelectronic device to accurately obtain the true value of the measured physical quantity, thereby extending the service life of the microelectronic device. Attached Figure Description

[0066] Figure 1 The diagram shows a flow chart of the fabrication method of the microelectronic device packaging structure of the present invention.

[0067] Figure 2 The diagram shows a process flow diagram of a method for fabricating a microelectronic device packaging structure, which is an example of the present invention.

[0068] Figures 3 to 18 The diagram shows a cross-sectional structure of each step in the preparation method of the first structural unit, which is an example of the present invention.

[0069] Figures 19 to 34 The diagram shows a cross-sectional structure of each step in the preparation method of the second structural unit as an example of the present invention.

[0070] Figure 35 The diagram shows a cross-sectional structure of a first structural unit and a second structural unit bonded together as an example of the present invention.

[0071] Figure 36 The diagram shown is a top view of a micro heater, a third lead-out portion, and a second support layer, as an example of the present invention.

[0072] Figure 37 The diagram shown is a top view of a micro heater, a second support structure, a third lead-out portion, and a second support layer, as an example of the present invention.

[0073] Figure 38 The diagram shown is a top view of the temperature monitoring section, which is an example of the present invention.

[0074] Figure 39 The diagram shown is a top view of the temperature monitoring section, which is another example of the present invention.

[0075] Figure 40 The diagram shown is a cross-sectional structural schematic of the temperature monitoring section as an example of the present invention.

[0076] Component labeling: 100 First substrate, 101 First side of the first substrate, 102 Second side of the first substrate, 103 First support layer, 104 N-type doped first portion, 105 P-type doped first portion, 106 N-type doped second portion, 107 P-type doped second portion, 108 Miniature vacuum gauge circuit material layer, 109 Miniature vacuum gauge, 110 Second lead, 111 First cover layer, 112 Second contact hole, 113 First bonding portion, 114 First wire bonding pad, 115 Second wire bonding pad, 116 Third wire bonding pad, 117 Temperature monitoring section electrical lead layer, 118 Second cover layer, 119 First etched window, 120 First cavity, 121 First lead, 122 First contact hole, 123 Fourth contact hole, 124 Temperature monitoring section, 125 Third contact hole, 126 First electrode material layer, 200 Second substrate, 201 First side of the second substrate, 202 Second surface of the second substrate, 203 Second support layer, 204 Micro heater circuit material layer, 205 Third lead-out portion, 2051 Lead-out pad, 2052 Lead-out wire, 206 Micro heater, 207 Third cover layer, 208 Fifth contact hole, 209 Second electrode material layer, 210 Second bonding portion, 211 Connecting pad, 212 Third cavity, 213 Dicing via, 214 Second etching window, 215 Second cavity, 216 Mask, 217 Getter film, 218 Vacuum degree control portion, 219 Fourth cover layer, 220 Deposition window, 300 Micro sealed vacuum cavity, 301 First vacuum cavity, 302 Second vacuum cavity, 303 Gas molecule channel, 304 Electrical connection wire, 305 Packaging substrate, 306 Micro heater film area, 307 Second support structure, 3071 Second support arm, 3072 Second support body. Detailed Implementation

[0077] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0078] Please see Figures 1 to 40It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0079] This embodiment provides a method for fabricating a microelectronic device packaging structure, such as... Figure 1 As shown, the preparation method includes:

[0080] S1 provides a first structural unit and a second structural unit; a miniature vacuum gauge is integrated in the first structural unit or the second structural unit;

[0081] S2, the first structural unit and the second structural unit are bonded together to form a miniature sealed vacuum cavity. The miniature vacuum gauge is located inside the miniature sealed vacuum cavity and is used to monitor the vacuum level inside the miniature sealed vacuum cavity.

[0082] The fabrication method of the microelectronic device packaging structure in this embodiment integrates a micro vacuum gauge into the micro sealed vacuum cavity of the microelectronic device packaging structure, which enables real-time in-situ monitoring of the vacuum level inside the micro sealed vacuum cavity of the microelectronic device packaging structure. This manufacturing method has the advantages of simple process and high compatibility.

[0083] As an example, the micro vacuum gauge includes one or more combinations of MEMS Pirani vacuum gauge structures and diode-type vacuum gauge structures.

[0084] As an example, the materials of the micro vacuum gauge include one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, tantalum, chromium, titanium nitride, polycrystalline silicon, monocrystalline silicon, carbon nanotubes, and graphene.

[0085] As a further preferred example, the miniature sealed vacuum cavity formed by the bonding connection of the first structural unit and the second structural unit also integrates a vacuum degree control part and / or a temperature monitoring part. The vacuum degree control part is used to control the vacuum degree in the miniature sealed vacuum cavity, and the temperature monitoring part is used to monitor the temperature in the miniature sealed vacuum cavity and perform temperature compensation for the miniature vacuum gauge.

[0086] As an example, the temperature monitoring section includes one or more combinations of diodes, thermistors, thermocouples, thermopile, and resonators.

[0087] Preferably, in step S1 of this embodiment, the first structural unit integrates the micro vacuum gauge and the temperature monitoring part, and the second structural unit integrates the vacuum degree control part. By integrating the micro vacuum gauge, the vacuum degree control part, and the temperature monitoring part into the same micro sealed vacuum cavity, real-time in-situ precise monitoring and online precise control of the vacuum degree within the micro sealed vacuum cavity where the microelectronic device is located can be achieved simultaneously, realizing closed-loop control of the vacuum degree within the cavity.

[0088] At this point, as a specific example, such as Figure 2 As shown, the preparation method in step S1 includes:

[0089] S10 provides a first structural unit and a second structural unit; wherein...

[0090] The first structural unit includes a first substrate, the first substrate having a first surface and a second surface opposite to each other, and the temperature monitoring part, the first cavity and the micro vacuum gauge suspended on the top of the first cavity are formed on the first surface of the first substrate;

[0091] The second structural unit includes a second substrate, which has a first surface and a second surface facing each other. A second cavity, a third cavity, and the vacuum control portion suspended on the top of the second cavity are formed on the first surface of the second substrate.

[0092] The preparation method of step S2 includes:

[0093] S20, the first bonding portion on the first surface of the first substrate of the first structural unit and the second bonding portion on the first surface of the second substrate of the second structural unit are bonded together, wherein the second cavity of the second structural unit corresponds to the position of the temperature monitoring portion of the first structural unit, and the third cavity of the second structural unit corresponds to the position of the first cavity of the first structural unit, so as to form a micro-sealed vacuum cavity. The micro-sealed vacuum cavity includes a first vacuum cavity, a second vacuum cavity, and a gas molecule channel connecting the first vacuum cavity and the second vacuum cavity in sequence. The first vacuum cavity is composed of the second cavity, and the second vacuum cavity is composed of the first cavity and the third cavity.

[0094] The following detailed description, in conjunction with the accompanying drawings, illustrates the fabrication method of the microelectronic device packaging structure integrating the temperature monitoring section, the micro vacuum gauge, and the vacuum degree control section of this embodiment.

[0095] First, proceed to step S1, providing the first structural unit (see reference). Figure 19 ) and the second structural unit (reference) Figure 35 );in,

[0096] refer to Figures 3 to 19 The first structural unit includes a first substrate 100, which has a first surface 101 and a second surface 102 facing each other. The temperature monitoring portion 124, the first cavity 120 and the miniature vacuum gauge 109 suspended on the top of the first cavity 120 are formed on the first surface 101 of the first substrate 100.

[0097] refer to Figures 20 to 35 The second structural unit includes a second substrate 200, which has a first surface 201 and a second surface 202 facing each other. A second cavity 215, a third cavity 212 and the vacuum control portion 218 suspended on the top of the second cavity 215 are formed on the first surface 201 of the second substrate 200.

[0098] For a specific example, see Figures 3 to 19 The method for preparing the first structural unit includes:

[0099] S11, such as Figure 3 and Figure 4 As shown, a first substrate 100 is provided, and a first support layer 103 is formed on a first surface 101 of the first substrate 100.

[0100] As an example, the first substrate 100 includes one or more combinations of silicon substrate, SiC substrate, quartz substrate, sapphire substrate and glass substrate.

[0101] As an example, the first support layer 103 can be a thin film made of a single material, a composite thin film made of multiple materials, or a composite thin film formed by stacking multiple thin films of single materials. In one embodiment, the first support layer 103 can be a single-layer thin film made of silicon nitride with a thickness of 0.7µm. In another embodiment, the first support layer 103 can be a single-layer thin film made of aluminum nitride with a thickness of 0.7µm. In one embodiment, the first substrate 100 can be a silicon substrate, and the first support layer 103 can be formed on the surface of the first substrate 100 using processes including but not limited to low-pressure chemical vapor deposition (LPCVD) or magnetron sputtering. Furthermore, the first support layer 103 can be formed on both the first surface 101 and the second surface 102 of the first substrate 100. The first support layer 103 has two main functions: first, to achieve mutual shielding between the subsequently formed micro vacuum gauge 109 and the material of the first substrate 100; and second, to support the micro vacuum gauge 109. The specific material and thickness of the first support layer 103 can be designed according to the performance requirements of the micro vacuum gauge 109 circuit, and no excessive restrictions are imposed here.

[0102] S12, as Figure 8 As shown, the temperature monitoring portion 124 is formed by ion implantation in a predetermined area of ​​the first surface 101 of the first substrate 100.

[0103] refer to Figures 5 to 8 The method for forming the temperature monitoring portion 124 by ion implantation on a predetermined region of the first surface 101 of the first substrate 100 includes:

[0104] like Figure 5 As shown, an N-type doping depth is applied to a predetermined region on the first surface 101 of the first substrate 100 to form an N-type doped first portion 104; as Figure 6 As shown, the N-type doped first portion 104 is subjected to P-type doping at a predetermined depth in a predetermined region to form the P-type doped first portion 105; as Figure 7 As shown, the N-type doped first portion 104 is subjected to N-type doping to a predetermined depth in a predetermined region to form the N-type doped second portion 106; as Figure 8As shown, a preset depth of P-type doping is performed on a preset region of the first P-type doped portion 105 to form a second P-type doped portion 107; wherein, the second N-type doped portion 106 is arranged around and spaced apart from the periphery of the first P-type doped portion 105, the doping concentration of the second N-type doped portion 106 is greater than the doping concentration of the first N-type doped portion 104, and the doping concentration of the second P-type doped portion 107 is greater than the doping concentration of the first P-type doped portion 105.

[0105] The N-type doped first portion 104, the P-type doped first portion 105, the N-type doped second portion 106, and the P-type doped second portion 107 constitute the temperature monitoring portion 124. The N-type doped first portion 104, the P-type doped first portion 105, the N-type doped second portion 106, and the P-type doped second portion 107 can all be formed using conventional ion implantation, annealing, and related processes.

[0106] As an example, the temperature monitoring section 124 includes one or more combinations of diodes, thermistors, thermocouples, thermopile and resonators.

[0107] As an example, the first N-type doping portion 104 may use, but is not limited to, group V element phosphorus as an impurity atom. The first P-type doping portion 105 may use, but is not limited to, group III element boron as an impurity atom. The second N-type doping portion 106 may use, but is not limited to, group V element phosphorus as an impurity atom. The second P-type doping portion 107 may use, but is not limited to, group III element boron as an impurity atom.

[0108] For example, please refer to Figure 38 and Figure 39 ,in, Figure 38 The diagram shown is a top view of the temperature monitoring section 124 as described in one embodiment. Figure 39 The diagram shown is a top view of the temperature monitoring section 124 in another embodiment, which is composed of the N-type doped first portion 104, the N-type doped second portion 106, the P-type doped first portion 105, and the P-type doped second portion 107. The short distance between the N-type doped second portion 106 and the P-type doped second portion 107 reduces the bulk equivalent resistance, which helps to improve the linearity and accuracy of temperature monitoring. A cross-sectional view of the temperature monitoring section 124 is shown below. Figure 40As shown, a PN junction is formed at the interface between the N-type doped first portion 104 and the P-type doped first portion 105. Its forward bias voltage under constant current drive changes linearly with temperature, thus it can be used for temperature monitoring. The doping concentration of the N-type doped second portion 106 is greater than that of the N-type doped first portion 104, and the doping concentration of the P-type doped second portion 107 is greater than that of the P-type doped first portion 105, reducing the bulk equivalent resistance in the circuit and thus serving as an electrical lead-out. The positions of the N-type doped portions (the N-type doped first portion 104 and the N-type doped second portion 106) and the P-type doped portions (the P-type doped first portion 105 and the P-type doped second portion 107) can be flexibly interchanged, and can be selected as needed, and are not limited to the examples listed here.

[0109] S13, as Figure 10 As shown, the miniature vacuum gauge 109 is formed on the first support layer 103.

[0110] Furthermore, such as Figure 10 As shown, when forming the miniature vacuum gauge 109 on the first support layer 103, the method further includes forming a first lead-out portion 121 electrically connected to the miniature vacuum gauge 109 and a second lead-out portion 110 electrically connected to the temperature monitoring portion 124.

[0111] As a specific example, the method for forming the miniature vacuum gauge 109, the first lead-out portion 121, and the second lead-out portion 110 includes the following steps:

[0112] refer to Figure 9 First, a micro vacuum gauge circuit material layer 108 is formed on the first support layer 103. The material of the micro vacuum gauge circuit material layer 108 includes one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, titanium nitride, polysilicon, single-crystal silicon, carbon nanotubes, and graphene. The specific material can be selected as needed and is not limited to the examples listed herein. In this embodiment, the micro vacuum gauge circuit material layer 108 is a 0.15 μm thick molybdenum layer, formed using conventional magnetron sputtering and related processes.

[0113] refer to Figure 10Next, the micro vacuum gauge circuit material layer 108 is patterned to form the micro vacuum gauge 109, the first lead-out portion 121, and the second lead-out portion 110. As an example, conventional photolithography, metal etching, and related processes can be used to pattern the micro vacuum gauge circuit material layer 108 to form a composite series micro vacuum gauge circuit structure. The metal etching process includes, but is not limited to, ion beam etching (IBE) technology.

[0114] As an example, the micro vacuum gauge 109 includes one or more combinations of MEMS Pirani vacuum gauge structure and diode type vacuum gauge structure.

[0115] As an example, the materials of the micro vacuum gauge 109 include one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, tantalum, chromium, titanium nitride, polycrystalline silicon, monocrystalline silicon, carbon nanotubes, and graphene.

[0116] S14, as Figure 16 As shown, a first etched window 119 is formed through the first support layer 103 to expose the first surface 101 of the first substrate 100; as Figure 17 As shown, the first substrate 100 is etched through the first etching window 119 to obtain the first cavity 120; and a portion of the first support layer 103 is suspended on top of the first cavity 120 as the first support structure of the micro vacuum gauge 109. The first support structure includes a first support body and a first support arm. One end of the first support arm is connected to the first support body, and the other end is connected to the rigid portion of the first substrate 100.

[0117] As a specific example, see [reference] Figures 11 to 18 The preparation method of step S14 includes the following steps:

[0118] like Figure 12 As shown, a first covering layer 111 is formed to cover the first support layer 103 and the micro vacuum gauge 109, and to expose the temperature monitoring part 124, the first lead-out part 121 and the second lead-out part 110.

[0119] Further, as an example, a method for forming a first covering layer 111 that covers the first support layer 103 and the miniature vacuum gauge 109, and exposes the temperature monitoring portion 124, the first lead-out portion 121, and the second lead-out portion 110 includes the following steps:

[0120] like Figure 11As shown, a first covering layer 111 is first formed to cover the first support layer 103, the micro vacuum gauge 109, the first lead-out portion 121 and the second lead-out portion 110.

[0121] As an example, the first capping layer 111 can be a thin film made of a single material, a composite thin film made of multiple materials, or a composite thin film formed by stacking multiple thin films of single materials. In one embodiment, the first capping layer 111 can be a single thin film made of silicon nitride with a thickness of 0.2µm. In another embodiment, the first capping layer 111 can be a single thin film made of aluminum nitride with a thickness of 0.2µm. In one embodiment, the first capping layer 111 can be prepared using processes including but not limited to PECVD, magnetron sputtering, and related processes. The main function of the first capping layer 111 is to prevent the suspended thin film structure from being damaged due to excessive stress during the subsequent etching of bulk silicon. The specific material and thickness of the first capping layer 111 can be designed according to the performance requirements of the micro vacuum gauge 109 circuit.

[0122] like Figure 12 As shown, conventional photolithography, etching, and related processes are used to pattern the first cover layer 111 to form the first contact hole 122, the second contact hole 112, the third contact hole 125, and the fourth contact hole 123. For example, when the material of the first cover layer 111 is silicon nitride, the etching process can be performed using a silicon nitride etching machine; when the material of the first cover layer 111 is aluminum nitride, the etching process can be performed using an aluminum nitride etching machine. The first contact hole 122 exposes the first lead-out portion 121, the second contact hole 112 and the third contact hole 125 expose the second lead-out portion 110, and the fourth contact hole 123 exposes the temperature monitoring portion 124.

[0123] like Figure 14 As shown, a first wire bonding pad 114 electrically connected to the first lead-out portion 121, a second wire bonding pad 115 electrically connected to the vacuum degree control portion 218 after step S20, and a third wire bonding pad 116 electrically connected to the second lead-out portion 110 are then formed; after the bonding connection in step S20, the first wire bonding pad 114, the second wire bonding pad 115, and the third wire bonding pad 116 are all located outside the miniature sealed vacuum chamber 300.

[0124] For a specific example, see Figure 13 and Figure 14The method for forming a first wire bonding pad 114 electrically connected to the first lead-out portion 121, a second wire bonding pad 115 electrically connected to the vacuum degree control portion 218 after step S22, and a third wire bonding pad 116 electrically connected to the second lead-out portion 110 includes:

[0125] like Figure 13 As shown, a first electrode material layer 126 is formed covering the first cover layer 111, and the first electrode material layer 126 fills the contact holes that expose the temperature monitoring portion 124, the first lead-out portion 121, and the second lead-out portion 110 (see reference). Figure 12 The first contact hole 122, the second contact hole 112, the third contact hole 125, and the fourth contact hole 123.

[0126] like Figure 14 As shown, the first electrode material layer 126 is patterned to form the first wire bonding pad 114, the second wire bonding pad 115, and the third wire bonding pad 116, and simultaneously forms the first bonding portion 113. In addition, a temperature monitoring electrical lead-out layer 117 is also formed. As an example, conventional photolithography, etching, and associated processes can be used to pattern the first electrode material layer 126; for example, aluminum etching can be performed using a metal etching machine.

[0127] like Figure 15 As shown, a second cover layer 118 is then formed covering the first cover layer 111, the first wire bonding pad 114, the second wire bonding pad 115, and the third wire bonding pad 116.

[0128] The second capping layer 118 has two main functions: first, to prevent the first wire bonding pad 114, the second wire bonding pad 115, the third wire bonding pad 116, and the first bonding portion 113 from chemically reacting with the etching solution during subsequent silicon etching; and second, to prevent the first wire bonding pad 114, the second wire bonding pad 115, the third wire bonding pad 116, and the first bonding portion 113 from being oxidized during subsequent processing. The specific material and thickness of the second capping layer 118 can be designed according to the performance requirements of the micro vacuum gauge 109 circuit.

[0129] As an example, the second capping layer 118 can be a thin film made of a single material, a composite thin film made of multiple materials, or a composite thin film formed by stacking multiple thin films of single materials. In one embodiment, the second capping layer 118 is a single thin film made of silicon nitride with a thickness of 0.5 µm. In another embodiment, the second capping layer 118 is a composite thin film made of silicon oxide and silicon nitride with thicknesses of 0.5 µm and 0.3 µm, respectively. In one embodiment, the second capping layer 118 can be prepared using a conventional PECVD process.

[0130] like Figure 16 As shown, a first etched window 119 is then formed through the second cover layer 118, the first cover layer 111, and the first support layer 103 to expose the first surface 101 of the first substrate 100.

[0131] As an example, conventional photolithography, etching, and associated processes can be used to etch the second cover layer 118, the first cover layer 111, and the first support layer 103 to obtain the first etched window 119. For example, silicon nitride etching can be performed using a silicon nitride etching machine, and silicon oxide etching can be performed using a silicon oxide etching machine.

[0132] like Figure 17 As shown, the first substrate 100 is then etched through the first etching window 119 to obtain the first cavity 120; and a portion of the first support layer 103 is suspended on top of the first cavity 120 as the first support structure of the micro vacuum gauge 109. The first support structure includes a first support body and a first support arm. One end of the first support arm is connected to the first support body, and the other end is connected to the rigid portion of the first substrate 100.

[0133] As an example, when the first substrate 100 is a silicon substrate, the first substrate 100 can be etched using a gas or plasma that has an etching effect on silicon. In this case, the gas or plasma reaches the first surface 101 of the first substrate 100 through the first etching window 119 to achieve etching. Etching gases include, but are not limited to, xenon difluoride (XeF2) or sulfur hexafluoride (SF6), and etching plasmas include, but are not limited to, sulfur hexafluoride (SF6).

[0134] Alternatively, a liquid that etches silicon can be used to etch the first substrate 100. In this case, the etching solution also reaches the first surface 101 of the first substrate 100 through the first etching window 119 to achieve etching. Etching solutions include, but are not limited to, potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH).

[0135] Specifically, the first etching window 119 is used not only to provide an etchant through the window, but also to define the shape of the first support body and the first support arm.

[0136] As an example, the shape of the first support body can be adjusted according to usage requirements without changing the longitudinal structure of its heating structure. The shape of the first support arm includes, but is not limited to, effective connection methods such as straight line, broken line, or arc. The number of the first support arms can be adjusted as needed.

[0137] Specifically, the first cavity 120 obtained after etching makes the main structure of the micro vacuum gauge 109 float, connected to the first substrate 100 only through a cantilever beam (the first support arm). As an example, when the first support arm is a polygonal shape, its corners are preferably rounded to help improve stress concentration.

[0138] like Figure 18 As shown, the second cover layer 118 is then removed.

[0139] As an example, the second cover layer 118 can be removed using conventional etching and associated processes. For instance, silicon nitride etching can be performed using a silicon nitride etching machine, and silicon oxide etching can be performed using a silicon oxide etching machine.

[0140] This completes the fabrication of the first structural unit.

[0141] As a specific example, the method for preparing the second structural unit includes:

[0142] like Figure 19 and Figure 20 As shown, a second substrate 200 is provided, and a second support layer 203 is formed on the first surface 201 of the second substrate 200.

[0143] As an example, the second substrate 200 includes one or more combinations of silicon substrate, SiC substrate, quartz substrate, sapphire substrate and glass substrate.

[0144] As an example, the second support layer 203 can be a thin film made of a single material, a composite thin film made of multiple materials, or a composite thin film formed by stacking multiple thin films of single materials. In one embodiment, the second support layer 203 is a single thin film made of silicon nitride with a thickness of 0.5µm. In one embodiment, the second substrate 200 is a silicon substrate, and the second support layer 203 is formed on the surface of the second substrate 200 using conventional LPCVD process and corresponding supporting processes. Furthermore, the second support layer 203 can also be formed on both the first surface 201 and the second surface 202 of the second substrate 200. (Reference) Figure 34 The second support layer 203 has three main functions: first, to provide electrical insulation between the material of the vacuum control section 218 and the material of the second substrate 200; second, to support the micro heater 206 in the vacuum control section 218; and third, to provide thermal insulation between the micro heater 206 and the second substrate 200, so that the heat generated by the micro heater 206 after being energized can effectively flow towards the subsequently formed getter film 217. The specific material and thickness of the second support layer 203 can be designed according to the required performance of the vacuum control section 218.

[0145] like Figure 34 As shown, the vacuum control portion 218 is formed on the second support layer 203, and the vacuum control portion 218 includes a micro heater 206 and a getter film 217.

[0146] like Figure 34 As shown, a second etching window 214 is formed through the second support layer 203; the second substrate 200 is etched through the second etching window 214 to obtain the second cavity 215; and a portion of the second support layer 203 is suspended above the second cavity 215 as a second support structure for the micro heater 206. The second support structure includes a second support body and a second support arm. One end of the second support arm is connected to the second support body, and the other end is connected to the rigid portion of the second substrate 200.

[0147] As a further specific example, see [reference] Figures 19 to 34 The method for preparing the second structural unit includes the following steps:

[0148] like Figure 22 As shown, the micro heater 206 and the third lead-out portion 205 electrically connected to the micro heater 206 are formed on the second support layer 203.

[0149] As a specific example, the method for forming the micro heater 206 and the third lead-out portion 205 includes the following steps:

[0150] refer to Figure 21First, a micro-heater circuit material layer 204 is formed on the second support layer 203. The material of the micro-heater circuit material layer 204 includes one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, titanium nitride, polysilicon, single-crystal silicon, carbon nanotubes, and graphene. The specific material can be selected as needed and is not limited to the examples listed herein. In this embodiment, the micro-heater circuit material layer 204 is a 0.2µm thick titanium nitride layer, formed using conventional magnetron sputtering and associated processes.

[0151] refer to Figure 22 Next, the micro heater circuit material layer 204 is patterned to form the micro heater 206 and the third lead-out portion 205. As an example, conventional photolithography, metal etching, and related processes can be used to pattern the micro heater circuit material layer 204 to obtain the micro heater 206 and the third lead-out portion 205. The metal etching process includes, but is not limited to, the IBE process.

[0152] As an example, the material of the micro heater 206 includes one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, tantalum, chromium, titanium nitride, polycrystalline silicon, monocrystalline silicon, carbon nanotubes, and graphene.

[0153] like Figure 24 As shown, a third cover layer 207 is formed that covers the second support layer 203 and the micro heater 206, and exposes the third lead-out portion 205.

[0154] As a specific example, a method for forming a third covering layer 207 that covers the second support layer 203 and the micro heater 206 and exposes the third lead-out portion 205 includes the following steps:

[0155] like Figure 23 As shown, a third covering layer 207 is first formed to cover the second support layer 203, the micro heater 206, and the third lead-out portion 205.

[0156] As an example, the third capping layer 207 can be a thin film made of a single material, a composite thin film made of multiple materials, or a composite thin film formed by stacking multiple thin films of single materials. In one embodiment, the third capping layer 207 is a single thin film made of silicon nitride with a thickness of 0.5 µm. In another embodiment, the third capping layer 207 is a composite thin film made of silicon nitride and silicon oxide with thicknesses of 0.2 µm and 0.3 µm, respectively. In one embodiment, the third capping layer 207 is prepared using a conventional PECVD process. (Reference) Figure 34 The third cover layer 207 has two main functions: first, to provide electrical insulation between the microheater 206 and the subsequently formed getter film 217; and second, to effectively conduct the heat generated by the microheater 206 to the getter film 217, so that the temperature of the getter film 217 reaches its activation temperature. The specific material and thickness of the third cover layer 207 can be designed according to the required performance of the microheater 206.

[0157] like Figure 24 As shown, conventional photolithography, etching, and related processes are used to etch the third cover layer 207 to form the fifth contact hole 208, which exposes the third lead-out portion 205. For example, silicon nitride etching can be performed using a silicon nitride etching machine, and silicon oxide etching can be performed using a silicon oxide etching machine.

[0158] like Figure 26 As shown, a connection pad 211 electrically connected to the third lead-out portion 205 is then formed, referencing... Figure 35 After the bonding connection in step S20, the bonding pad 211 is located outside the micro sealed vacuum chamber 300.

[0159] For a specific example, see Figure 25 and Figure 26 The method for forming the connection pad 211 electrically connected to the third lead-out portion 205 includes:

[0160] like Figure 25 As shown, a second electrode material layer 209 is formed to cover the third cover layer 207, and the second electrode material layer 209 fills the contact hole (specifically the fifth contact hole 208) that exposes the third lead-out portion 205.

[0161] Specifically, the material and thickness of the second electrode material layer 209 can be designed according to the required performance of the vacuum degree control section 218.

[0162] In some embodiments, the material of the second electrode material layer 209 may be one or more combinations of platinum, tungsten, gold, aluminum, germanium, copper, nickel, tantalum, titanium, and chromium.

[0163] In other embodiments, the material of the second electrode material layer 209 may also be a semiconductor material, such as polysilicon. When polysilicon is used as the material of the second electrode material layer 209, the polysilicon can be doped as needed to adjust its conductivity.

[0164] In some other embodiments, the material of the second electrode material layer 209 may also be a metal compound.

[0165] In one embodiment, the second electrode material layer 209 is a single thin film made of metallic germanium with a thickness of 0.4 µm.

[0166] In one embodiment, the second electrode material layer 209 is prepared using a conventional PVD process.

[0167] like Figure 26 As shown, the second electrode material layer 209 is patterned to form the connection pad 211, and preferably the second bonding portion 210 can also be formed at the same time.

[0168] As an example, the second electrode material layer 209 can be patterned using conventional photolithography, etching, and associated processes. For instance, the germanium etching process can be performed using a metal etching machine.

[0169] like Figure 27 As shown, the third cavity 212 is formed by extending from the surface of the third cover layer 207 away from the second substrate 200 to a predetermined depth in the second substrate 200.

[0170] The main function of the third cavity 212 is to serve as a heat sink for the micro vacuum gauge 109 after the micro sealed vacuum cavity 300 is fabricated. The structure and depth of the third cavity 212 are designed according to the required performance of the micro vacuum gauge 109.

[0171] As an example, the third cavity 212 can be fabricated using conventional photolithography, etching, and related processes. For instance, silicon nitride etching can be performed using a silicon nitride etching machine, and bulk silicon etching can be performed using a deep silicon etching machine.

[0172] In one embodiment, the third cavity 212 has a rectangular top view and a depth of 10µm.

[0173] After the third cover layer 207 extends from the surface away from the second substrate 200 to a predetermined depth in the second substrate 200 to form the third cavity 212, the method further includes forming a plurality of dicing through holes 213 penetrating the third cover layer 207, the second support layer 203 and the second substrate 200. After step S20, the dicing through holes 213 expose the first wire bonding pad 114, the second wire bonding pad 115 and the third wire bonding pad 116.

[0174] By forming the dicing through-hole 213, after the micro-sealed vacuum chamber 300 is prepared, there is no need to open the dicing channel by etching; dicing and wire bonding testing can be performed directly, further reducing the risk of chipping and damage during the process. The shape of the dicing through-hole 213 is designed according to actual needs. In one embodiment, the cross-sectional shape of the dicing through-hole 213 is rectangular.

[0175] As an example, the dicing via 213 can be prepared using conventional photolithography, etching, and related processes. For instance, silicon nitride etching can be performed using a silicon nitride etching machine, and bulk silicon etching can be performed using a deep silicon etching machine.

[0176] like Figure 29 As shown, a fourth cover layer 219 is then formed covering the third cover layer 207, the connecting pads 211, and the third cavity 212.

[0177] The fourth capping layer 219 has two main functions: first, to prevent the connecting pads 211, the second bonding portion 210, and the third cavity 212 from chemically reacting with the etching solution during subsequent silicon etching; and second, to prevent the connecting pads 211 and the second bonding portion 210 from being oxidized during subsequent processing. The specific material and thickness of the fourth capping layer 219 can be designed according to the required performance of the vacuum degree control section 218 electrode.

[0178] As an example, the fourth capping layer 219 can be a thin film made of a single material, a composite thin film made of multiple materials, or a composite thin film formed by stacking multiple thin films of single materials. In one embodiment, the fourth capping layer 219 is a single thin film made of silicon nitride with a thickness of 0.5 µm. In another embodiment, the fourth capping layer 219 is a composite thin film made of silicon oxide and silicon nitride with thicknesses of 0.5 µm and 0.3 µm, respectively.

[0179] In one embodiment, the fourth capping layer 219 is prepared using a conventional PECVD process.

[0180] like Figure 30 As shown, a second etched window 214 is then formed through the fourth cover layer 219, the third cover layer 207 and the second support layer 203 to expose the first surface 201 of the second substrate 200.

[0181] As an example, conventional photolithography, etching, and associated processes can be used to etch the fourth cover layer 219, the third cover layer 207, and the second support layer 203 to obtain the second etched window 214. For example, silicon nitride etching can be performed using a silicon nitride etching machine, and silicon oxide etching can be performed using a silicon oxide etching machine.

[0182] like Figure 31 As shown, the second substrate 200 is then etched via the second etching window 214 to obtain the second cavity 215; Reference Figure 37 And a portion of the second support layer 203 is suspended above the second cavity 215 as the second support structure 307 of the micro heater 206. The second support structure 307 includes a second support body 3072 and a second support arm 3071. One end of the second support arm 3071 is connected to the second support body 3072, and the other end is connected to the rigid portion of the second substrate 200.

[0183] As an example, such as Figure 36 The image shows a top view of the microheater 206, the third lead-out portion 205, and the second support layer 203 in one embodiment. The microheater 206 includes a microheater thin film region 306. The third lead-out portion 205 includes a lead wire 2052 and a lead-out disk 2051, and there are two third lead-out portions 205. The shape of the microheater thin film region 306 can be adjusted according to usage requirements without changing the longitudinal structure of its heating structure. The specific internal wiring can be freely designed as needed, and no excessive restrictions are imposed here. For example, please refer to... Figure 37The image shows a top view of the micro heater 206, the second support structure 307, the third lead-out portion 205, and the second support layer 203 in one embodiment. The second support body 3072 of the micro heater 206 is rectangular, and the second support arms 3071 of the micro heater 206 are polygonal. There are four second support arms 3071. The micro heater 206 is located on the surface of the second support body 3072. There are two third lead-out portions 205, which are respectively connected to the positive and negative electrodes of the micro heater 206. The second support arms 3071 serve as channels for laying the lead-out wires 2052 and also provide a certain amount of support strength to the second support body 3072 supporting the micro heater 206 to prevent collapse.

[0184] As an example, the second substrate 200 can be etched using a gas or plasma that has an etching effect on silicon. In this case, the gas or plasma reaches the first surface 201 of the second substrate 200 through the second etching window 214 to achieve etching. The etching gas includes, but is not limited to, xenon difluoride (XeF2) or sulfur hexafluoride (SF6), and the etching plasma can include, but is not limited to, plasmas containing sulfur hexafluoride (SF6).

[0185] As an example, a liquid that etches silicon can also be used to etch the second substrate 200. In this case, the etching solution also reaches the first surface 201 of the second substrate 200 through the second etching window 214 to achieve etching. In some embodiments, the etching solution may include, for example, potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH).

[0186] Specifically, the second etching window 214 is used not only to provide an etchant passage window, but also to define the shape of the second support body 3072 and the second support arm 3071.

[0187] As an example, the second support body 3072 can be adjusted according to usage requirements without changing the longitudinal structure of its heating structure. The shape of the second support arm 3071 includes, but is not limited to, straight, broken, or arc-shaped effective connection methods. The number of the second support arms 3071 can be adjusted as needed. When the second support arm 3071 is broken, rounded corners are preferred at its corners to help improve stress concentration.

[0188] Specifically, the second cavity 215 obtained after etching makes the main structure of the vacuum control part 218 float, and is connected to the second substrate 200 only through the cantilever beam (the second support arm 3071).

[0189] like Figure 32 As shown, the fourth cover layer 219 is then removed.

[0190] As an example, the fourth cover layer 219 can be removed from the entire surface using conventional etching and associated processes. For instance, silicon nitride etching can be performed using a silicon nitride etching machine, and silicon oxide etching can be performed using a silicon oxide etching machine.

[0191] like Figure 34 As shown, a getter film 217 is then formed on the third cover layer 207, and the getter film 217 is located above the side of the microheater 206 away from the second substrate 200; the getter film 217 and the microheater 206 constitute the vacuum control portion 218. The getter film 217 and the microheater 206 are isolated from each other by the third cover layer 207, and the planar area of ​​the getter film 217 is smaller than the planar area of ​​the third cover layer 207.

[0192] As an example, the material of the getter film 217 includes one or more combinations of Ti-based non-evaporable getter materials, Zr-based non-evaporable getter materials, Hf-based non-evaporable getter materials, V-based non-evaporable getter materials, Nb-based non-evaporable getter materials, Ta-based non-evaporable getter materials, Pd-based non-evaporable getter materials, Cr / Ni alloy-based non-evaporable getter materials, and rare earth-based non-evaporable getter materials.

[0193] As an example, the thickness of the getter film 217 can be 0.5µm, and is not limited to this embodiment.

[0194] As a specific example, the method of forming the getter film 217 on the third cover layer 207 includes:

[0195] like Figure 33 As shown, a mask 216 is provided and is used to cover the surface of the structure on which the third cover layer 207 is formed. The mask 216 has a deposition window 220 of the getter film 217.

[0196] like Figure 33 As shown, based on the deposition window 220, the getter film 217 is deposited on the third capping layer 207 using, for example, a magnetron sputtering process.

[0197] like Figure 34 As shown, the mask 216 is removed.

[0198] The method of forming the getter film 217 using the mask 216 eliminates the need for etching the getter film 217, avoiding potential contamination of the getter film 217 during etching. Furthermore, the formation process is simple, and the mask 216 can be reused, reducing manufacturing costs.

[0199] This completes the fabrication of the first structural unit and the second structural unit.

[0200] like Figure 35 As shown, step S2 is then performed, whereby the first bonding portion 113 on the first surface 101 of the first substrate 100 of the first structural unit and the second bonding portion 210 on the first surface 201 of the second substrate 200 of the second structural unit are bonded together. The second cavity 215 of the second structural unit corresponds to the temperature monitoring portion 124 of the first structural unit, and the third cavity 212 of the second structural unit corresponds to the first cavity 120 of the first structural unit, thereby forming a miniature sealed vacuum cavity 300. The miniature sealed vacuum cavity 300 includes a first vacuum cavity 301, a second vacuum cavity 302, and a gas molecule channel 303 connecting the first vacuum cavity 301 and the second vacuum cavity 302. The first vacuum cavity 301 is composed of the second cavity 215, and the second vacuum cavity 302 is composed of the first cavity 120 and the third cavity 212.

[0201] The first substrate 100 and the second substrate 200 are spaced a certain distance apart in the region between the first vacuum chamber 301 and the second vacuum chamber 302 to define the gas molecule channel 303. The micro vacuum gauge 109 is used to monitor the internal vacuum level of the micro sealed vacuum chamber 300. The vacuum level control part 218 is used to adjust the internal vacuum level of the micro sealed vacuum chamber 300. The temperature monitoring part 124 is used to monitor the temperature inside the micro sealed vacuum chamber 300 and the temperature of the micro heater 206, so as to realize the precise monitoring and control of the vacuum level and complete the closed-loop control.

[0202] As an example, such as Figure 35 As shown, after step S2, the process further includes attaching the obtained overall package structure to the package substrate 305 and electrically leading out the first wire bonding pad 114, the second wire bonding pad 115 and the third wire bonding pad 116 through the electrical connection wire 304.

[0203] As a preferred example, the first bonding portion 113 fabricated on the first substrate 100 and the second bonding portion 210 fabricated on the second substrate 200, one of which includes an aluminum layer and the other includes a germanium layer, and the first bonding portion 113 and the second bonding portion 210 are bonded to each other to form an aluminum-germanium eutectic bonding layer.

[0204] Specifically, in the bonding region, the first structural unit and the second structural unit are in airtight contact, surrounding the micro-sealed vacuum cavity 300 and isolating it from the surrounding environment.

[0205] Specifically, the area, depth, and other structural parameters of the second cavity 215 constituting the first vacuum cavity 301 can be determined based on the structure of the vacuum degree control part 218 and the temperature monitoring part 124 housed within it. The main function of the first vacuum cavity 301 is to provide space for the vacuum degree control part 218 and the temperature monitoring part 124, allowing the circuit resistance of the micro heater 206 to become a suspended thin film, providing space for the movement of gas molecules and ensuring real-time control of the vacuum degree inside the micro-sealed vacuum cavity 300. The size, area, and other structural parameters of the micro heater 206 and the temperature monitoring part 124 can be determined based on the required vacuum degree control range and temperature monitoring range.

[0206] Specifically, the structural parameters such as the area and depth of the first cavity 120 and the third cavity 212 that make up the second vacuum chamber 302 can be determined according to the structure of the miniature vacuum gauge 109 it houses. The main function of the second vacuum chamber 302 is to provide a space for the miniature vacuum gauge 109, allowing it to levitate, providing conditions for its operation, and providing space for the movement of gas molecules, thereby ensuring real-time monitoring of the vacuum level inside the miniature sealed vacuum chamber 300. The size, area, and other structural parameters of the miniature vacuum gauge 109 can be determined according to the range of vacuum levels to be monitored within the miniature sealed vacuum chamber 300.

[0207] Specifically, the first vacuum chamber 301 and the second vacuum chamber 302 are interconnected through the gas molecule channel 303, which is formed by the gap between the film layers on the surfaces of the two substrates. This ensures that the vacuum level inside the miniature sealed vacuum chamber 300 remains consistent, removes many limitations, makes the structure more compact, reduces costs, and is suitable for more microelectronic devices.

[0208] In some embodiments, the orthographic projection shape of the gas molecule channel 303 onto the plane of the first substrate 100 is circular, rectangular, or polygonal, and the height of the gas molecule channel 303 ranges from 0.1µm to 100µm.

[0209] In some embodiments, in the region where the gas molecule channel 303 is located, the film layer on the first surface 101 of the first substrate 100 and the film layer on the first surface 201 of the second substrate 200 may not be etched. In other embodiments, in the region where the gas molecule channel 303 is located, at least one of 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 is etched to a certain depth so that the final gas molecule channel 303 has a greater height.

[0210] As an example, the fabrication method further includes the step of forming a MEMS sensor, which is formed in the micro-sealed vacuum cavity 300. The MEMS sensor includes one or more combinations of a MEMS gyroscope, a MEMS accelerometer, a MEMS pressure sensor, a MEMS resonator, and a MEMS micromirror. The MEMS sensor can be fabricated based on the first structural unit or the second structural unit.

[0211] Thus, a microelectronic device package structure integrating the temperature monitoring part 124, the micro vacuum gauge 109, and the vacuum degree control part 218 has been manufactured.

[0212] The method for fabricating a microelectronic device packaging structure integrating the temperature monitoring section 124, the micro vacuum gauge 109, and the vacuum degree control section 218 integrates the micro vacuum gauge 109, the vacuum degree control section 218, and the temperature monitoring section 124 inside the micro sealed vacuum cavity 300. This method is simple and highly compatible. While the micro vacuum gauge 109 measures the vacuum degree inside the micro sealed vacuum cavity 300, the vacuum degree control section 218 can also be activated, thereby controlling the vacuum degree inside the micro sealed vacuum cavity 300. Furthermore, the temperature monitoring section 124 monitors the temperature inside the micro sealed vacuum cavity 300 in real time to perform temperature compensation for the micro vacuum gauge 109 and monitors the temperature of the micro heater 206 to determine whether the getter film 217 has reached the required activation conditions. This provides strong support for the subsequent design and manufacturing of microelectronic devices.

[0213] Specifically, the vacuum levels inside the first cavity 120, the second cavity 215, and the third cavity 212 are positively correlated with the vacuum level inside the miniature sealed vacuum chamber 300. The vacuum level of the miniature sealed vacuum chamber 300 can be reflected by monitoring the reading of the miniature vacuum gauge 109, and the miniature vacuum gauge 109 is compensated for in real-time by monitoring the temperature inside the miniature sealed vacuum chamber 300 through the temperature monitoring section 124, thus obtaining an accurate measurement of the vacuum level inside the chamber. Specifically, when the vacuum level inside the miniature sealed vacuum chamber 300 differs from the vacuum level of the external environment where the chip is located, the reading of the miniature vacuum gauge 109 will change, enabling real-time monitoring of the vacuum level inside the miniature sealed vacuum chamber 300. When the reading of the miniature vacuum gauge 109 changes, it indicates that the vacuum level inside the miniature sealed vacuum chamber 300 has begun to change. At the same time, based on the vacuum level monitoring results, it can be determined whether the vacuum level control section 218 should be activated. If it is determined that it needs to be activated, the miniature heater 206 of the vacuum level control section 218 is energized to raise its temperature, and the getter film 217 starts to work, adsorbing gas molecules inside the miniature sealed vacuum chamber 300, so that the inside of the miniature sealed vacuum chamber 300 is restored to the required vacuum level, thereby providing the best working environment for the microelectronic device to ensure operational reliability and service life.

[0214] In summary, the fabrication method of the microelectronic device packaging structure of the present invention, by integrating a micro vacuum gauge into the micro-sealed vacuum cavity of the microelectronic device packaging structure, enables real-time in-situ monitoring of the vacuum level inside the micro-sealed vacuum cavity. This manufacturing method has the advantages of simple process and high compatibility. Furthermore, by integrating the micro vacuum gauge, vacuum level control part, and temperature monitoring part together inside the micro-sealed vacuum cavity, real-time in-situ accurate monitoring of the vacuum level inside the micro-sealed vacuum cavity can be performed based on the micro vacuum gauge and temperature monitoring part. When the vacuum level inside the micro-sealed vacuum cavity changes, the vacuum level control part can be heated and activated to maintain the vacuum level inside the micro-sealed vacuum cavity within the required range for the relevant microelectronic device, thereby ensuring the reliability of the microelectronic device performance and enabling the relevant microelectronic device to accurately obtain the true value of the measured physical quantity, thereby extending the service life of the microelectronic device. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0215] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for fabricating a microelectronic device packaging structure, characterized in that, The preparation method includes: S1 provides a first structural unit and a second structural unit; a miniature vacuum gauge is integrated in the first structural unit or the second structural unit; S2, the first structural unit and the second structural unit are bonded together to form a miniature sealed vacuum cavity. The miniature vacuum gauge is located inside the miniature sealed vacuum cavity and is used to monitor the vacuum level inside the miniature sealed vacuum cavity.

2. The method for fabricating a microelectronic device packaging structure according to claim 1, characterized in that: The micro vacuum gauge includes one or more combinations of MEMS Pirani vacuum gauge structure and diode-type vacuum gauge structure.

3. The method for fabricating a microelectronic device packaging structure according to claim 1, characterized in that: The materials of the micro vacuum gauge include one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, tantalum, chromium, titanium nitride, polycrystalline silicon, monocrystalline silicon, carbon nanotubes, and graphene.

4. The method for fabricating a microelectronic device packaging structure according to claim 1, characterized in that: The fabrication method further includes the step of forming a MEMS sensor, wherein the MEMS sensor is disposed in the micro-sealed vacuum cavity, and the MEMS sensor includes one or more combinations of MEMS gyroscope, MEMS accelerometer, MEMS pressure sensor, MEMS resonator and MEMS micromirror.

5. The method for fabricating a microelectronic device packaging structure according to claim 1, characterized in that: The miniature sealed vacuum cavity formed by the bonding connection of the first structural unit and the second structural unit also integrates a vacuum degree control part and / or a temperature monitoring part. The vacuum degree control part is used to control the vacuum degree in the miniature sealed vacuum cavity, and the temperature monitoring part is used to monitor the temperature in the miniature sealed vacuum cavity and perform temperature compensation on the miniature vacuum gauge.

6. The method for fabricating a microelectronic device packaging structure according to claim 5, characterized in that: The temperature monitoring component includes one or more combinations of diodes, thermistors, thermocouples, thermopile, and resonators.

7. The method for fabricating a microelectronic device packaging structure according to claim 5, characterized in that, In step S1, the first structural unit integrates the micro vacuum gauge and the temperature monitoring part, and the second structural unit integrates the vacuum degree control part; wherein, The preparation method of step S1 includes: S10 provides a first structural unit and a second structural unit; wherein... The first structural unit includes a first substrate, the first substrate having a first surface and a second surface opposite to each other, and the temperature monitoring part, the first cavity and the micro vacuum gauge suspended on the top of the first cavity are formed on the first surface of the first substrate; The second structural unit includes a second substrate, the second substrate having a first surface and a second surface opposite to each other, and a second cavity, a third cavity and the vacuum control portion suspended on the top of the second cavity are formed on the first surface of the second substrate; The preparation method of step S2 includes: S20, the first bonding portion on the first surface of the first substrate of the first structural unit and the second bonding portion on the first surface of the second substrate of the second structural unit are bonded together, wherein the second cavity of the second structural unit corresponds to the position of the temperature monitoring portion of the first structural unit, and the third cavity of the second structural unit corresponds to the position of the first cavity of the first structural unit, so as to form a micro-sealed vacuum cavity. The micro-sealed vacuum cavity includes a first vacuum cavity, a second vacuum cavity, and a gas molecule channel connecting the first vacuum cavity and the second vacuum cavity. The first vacuum cavity is composed of the second cavity, and the second vacuum cavity is composed of the first cavity and the third cavity.

8. The method for fabricating a microelectronic device packaging structure according to claim 7, characterized in that: The orthographic projection of the gas molecule channel onto the plane of the first substrate is circular, rectangular, or polygonal, and the height of the gas molecule channel is 0.1µm to 100µm.

9. The method for fabricating a microelectronic device packaging structure according to claim 7, characterized in that: The first substrate includes one or more combinations of silicon substrate, SiC substrate, quartz substrate, sapphire substrate and glass substrate; the second substrate includes one or more combinations of silicon substrate, SiC substrate, quartz substrate, sapphire substrate and glass substrate.

10. The method for fabricating a microelectronic device packaging structure according to claim 7, characterized in that, The method for preparing the first structural unit includes: The first substrate is provided, and a first support layer is formed on a first surface of the first substrate; The temperature monitoring section is formed by ion implantation into a predetermined area on the first surface of the first substrate. The miniature vacuum gauge is formed on the first support layer; A first etching window is formed through the first support layer to expose the first surface of the first substrate; the first substrate is etched through the first etching window to obtain the first cavity; and a portion of the first support layer is suspended on top of the first cavity as the first support structure of the micro vacuum gauge. The first support structure includes a first support body and a first support arm, one end of the first support arm is connected to the first support body, and the other end is connected to the rigid portion of the first substrate.

11. The method for fabricating a microelectronic device packaging structure according to claim 10, characterized in that, The method for forming the temperature monitoring portion by ion implantation in a predetermined area on the first surface of the first substrate includes: A predetermined area on the first surface of the first substrate is subjected to N-type doping to a predetermined depth to form an N-type doped first portion. A predetermined area of ​​the N-type doped first portion is subjected to P-type doping to a predetermined depth to form a P-type doped first portion. A predetermined area of ​​the N-type doped first portion is subjected to N-type doping to a predetermined depth to form an N-type doped second portion. A predetermined area of ​​the P-type doped first portion is subjected to P-type doping to a predetermined depth to form a P-type doped second portion. The N-type doped second portion is disposed around and spaced apart from the P-type doped first portion. The doping concentration of the N-type doped second portion is greater than that of the N-type doped first portion, and the doping concentration of the P-type doped second portion is greater than that of the P-type doped first portion. The N-type doped first portion, the P-type doped first portion, the N-type doped second portion, and the P-type doped second portion constitute the temperature monitoring portion.

12. The method for fabricating a microelectronic device packaging structure according to claim 10, characterized in that: The process of forming the micro vacuum timer on the first support layer further includes the steps of forming a first lead-out portion electrically connected to the micro vacuum timer and a second lead-out portion electrically connected to the temperature monitoring portion; A first etching window is formed that penetrates the first support layer to expose the first surface of the first substrate; the first substrate is etched through the first etching window to obtain the first cavity; The method of suspending a portion of the first support layer at the top of the first cavity as the first support structure of the micro vacuum gauge, wherein the first support structure includes a first support body and a first support arm, and one end of the first support arm is connected to the first support body and the other end is connected to the rigid portion of the first substrate includes: A first covering layer is formed to cover the first support layer and the micro vacuum gauge, and to expose the temperature monitoring part, the first lead-out part and the second lead-out part; A first wire bonding pad electrically connected to the first lead-out portion, a second wire bonding pad electrically connected to the vacuum degree control portion after step S20, and a third wire bonding pad electrically connected to the second lead-out portion are formed; after the bonding connection in step S20, the first wire bonding pad, the second wire bonding pad, and the third wire bonding pad are all located outside the micro sealed vacuum cavity. A second cover layer is formed covering the first cover layer, the first wire bonding pad, the second wire bonding pad, and the third wire bonding pad; A first etching window is formed that penetrates the second cover layer, the first cover layer, and the first support layer to expose the first surface of the first substrate; The first substrate is etched through the first etching window to obtain the first cavity; and a portion of the first support layer is suspended on top of the first cavity as the first support structure of the micro vacuum gauge. The first support structure includes a first support body and a first support arm. One end of the first support arm is connected to the first support body, and the other end is connected to the rigid portion of the first substrate. Remove the second overlay.

13. The method for fabricating a microelectronic device packaging structure according to claim 12, characterized in that, The method for forming the first wire bonding pad electrically connected to the first lead-out portion, the second wire bonding pad electrically connected to the vacuum degree control portion after step S20, and the third wire bonding pad electrically connected to the second lead-out portion includes: A first electrode material layer is formed to cover the first cover layer, and the first electrode material layer fills the contact holes that expose the temperature monitoring portion, the first lead-out portion and the second lead-out portion; The first electrode material layer is patterned to form the first wire bonding pad, the second wire bonding pad, and the third wire bonding pad, and the first bonding portion is formed simultaneously.

14. The method for fabricating a microelectronic device packaging structure according to claim 7, characterized in that, The method for preparing the second structural unit includes: The second substrate is provided, and a second support layer is formed on a first surface of the second substrate; The vacuum control portion is formed on the second support layer, and the vacuum control portion includes a micro heater and a getter film. A second etching window is formed that penetrates the second support layer; the second substrate is etched through the second etching window to obtain the second cavity; and a portion of the second support layer is suspended above the second cavity as a second support structure for the micro heater. The second support structure includes a second support body and a second support arm, one end of the second support arm is connected to the second support body, and the other end is connected to the rigid portion of the second substrate.

15. The method for fabricating a microelectronic device packaging structure according to claim 14, characterized in that: The materials of the micro heater include one or more combinations of titanium, nickel, molybdenum, tungsten, rhodium, platinum, iridium, aluminum, copper, gold, tantalum, chromium, titanium nitride, polycrystalline silicon, monocrystalline silicon, carbon nanotubes, and graphene.

16. The method for fabricating a microelectronic device packaging structure according to claim 14, characterized in that, The method for preparing the second structural unit includes: The micro heater and a third lead-out portion electrically connected to the micro heater are formed on the second support layer; A third covering layer is formed to cover the second support layer and the micro heater, and to expose the third lead-out portion; A connection pad is formed that is electrically connected to the third lead-out portion. After bonding in step S20, the connection pad is located outside the micro-sealed vacuum cavity. The third cavity is formed by extending from the surface of the third cover layer away from the second substrate to a predetermined depth in the second substrate; A fourth cover layer is formed, covering the third cover layer, the connecting pads, and the third cavity; A second etching window is formed that penetrates the fourth cover layer, the third cover layer, and the second support layer to expose the first surface of the second substrate; The second substrate is etched through the second etching window to obtain the second cavity; and a portion of the second support layer is suspended above the second cavity as the second support structure of the micro heater. The second support structure includes a second support body and a second support arm. One end of the second support arm is connected to the second support body, and the other end is connected to the rigid portion of the second substrate. Remove the fourth overlay layer; The getter film is formed on the third cover layer, and the getter film is located above the side of the micro heater away from the second substrate; the getter film and the micro heater constitute the vacuum control part.

17. The method for fabricating a microelectronic device packaging structure according to claim 16, characterized in that, The method for forming the connection pad electrically connected to the third lead, and after bonding in step S20, having the connection pad located outside the micro-sealed vacuum cavity, includes: A second electrode material layer is formed to cover the third cover layer, and the second electrode material layer fills the contact hole that exposes the third lead-out portion; The second electrode material layer is patterned to form the connection pads and simultaneously form the second bonding portion.

18. The method for fabricating a microelectronic device packaging structure according to claim 16, characterized in that: After the third cover layer extends from the surface away from the second substrate to a predetermined depth in the second substrate to form the third cavity, the method further includes the step of forming a plurality of diced through holes penetrating the third cover layer, the second support layer and the second substrate. After step S20, the diced through holes expose the first wire bonding pad, the second wire bonding pad and the third wire bonding pad.

19. The method for fabricating a microelectronic device packaging structure according to claim 16, characterized in that, The method of forming the getter film on the third cover layer includes: A mask is provided and the mask is placed over the surface of the structure on which the third capping layer is formed, wherein a deposition window for the getter film is formed in the mask; Based on the deposition window, the getter film is deposited on the third capping layer to form the getter film; Remove the mask.

20. The method for fabricating a microelectronic device packaging structure according to claim 16, characterized in that: The material of the getter film includes one or more combinations of Ti-based non-evaporable getter materials, Zr-based non-evaporable getter materials, Hf-based non-evaporable getter materials, V-based non-evaporable getter materials, Nb-based non-evaporable getter materials, Ta-based non-evaporable getter materials, Pd-based non-evaporable getter materials, Cr / Ni alloy-based non-evaporable getter materials, and rare earth-based non-evaporable getter materials.

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